4J1. General description. The periscope has an
internal range finding device of the stadimeter
type capable of giving both ranges and course
angles. The change from direct observation to
range reading or course measuring is quickly and
positively effective.
The range and course-angle finding device
is of the duplicate image type; the distance
between the images may be varied at will, so
that, for example, the water line of one image
may be brought into contact with the masthead
or funnel top of the other image. If the length
98
of the vessel is known or estimated and set on the
length of the target scale dial, the angle subtended is indicated in yards on the range scale
dial, against the known height of the vessel
on the height scale dial.
The device may be rotated 90 degrees in a plane
normal to the optical axis of the periscope.
This is done by continuing the clockwise motion
of the operating gear beyond the limit of the
vertical position of the separating mechanism;
thus the whole divided lens unit rotates 90 degrees.
In this position, the two images of the target
are at opposite edges of the field and the mechanism is in contact with its stops. Turning the
handwheel counterclockwise makes the two
images approach each other. Since the known
length of the target has been set on the length of
target scale dial opposite the stationary index
mark on the bottom of the stadimeter housing,
when the bow of one image touches the stern of
the other, the course angle is indicated on the
length of target scale dial against the previously
found range on the range scale dial.
The duplicate images are obtained in the following manner: The lower objective lens is divided into two substantially equal parts and
mounted in such a manner that the parts may be
moved against each other in a plane normal to
the vertical optical axis of the periscope and also
may be rotated in the same plane through 90 degrees.
The mechanism for these movements
is operated by a handwheel on the right-hand
side of the lower end of the periscope at a height
convenient for the operator.
Ordinary observation is obtained when each
half of the divided lens supplements the other
and thus forms a complete circle; then a single
image is visible in the eyepiece, and the joint
between the two halves of the lens lies in the vertical centerline. The stops of the mechanism are
in contact in this position.
When the lens halves are in the position for
ordinary observation, clockwise rotation of the
handwheel causes the halves to slide against each
other in opposite directions; this causes duplicate
images to appear in the eyepiece. The separation
of the images increases until a maximum is
reached, when further clockwise rotation causes
the divided lens unit to rotate through 90 degrees.
Counterclockwise rotation of the handwheel
then causes the two images to approach each
other until the two halves of the objective supplement each other and produce a single image. Further counterclockwise rotation of the handwheel
causes the divided lens unit to rotate and return
to the ordinary observing position, ready for the
next range and course angle finding operation.
The device gives readings independent of the
focus setting of the individual observer. It is
capable of bringing into coincidence two points
of the image that subtend an angle of from 0 degrees to
not more than 2 degrees of the field at high power. It is
provided with duplicate scale dials of Bakelite
attached to the outside of the periscope so that
range and course angle data may be read by an
assistant, if desired. One set of scale dials is located under the eyepiece at the lower end of the
eyepiece box, and the other set diametrically
opposite on the back of the periscope. Such scale
dials are not less than 2-inch outer diameter in
the case of the smallest scale dial, and so located
as to be easily readable. The graduations and
numbering on each scale dial are clear and
legible and each scale dial occupies as great an
angular portion on the dial on which it is engraved as is practicable. The angular movement
of the scale dial or scale dials connected to the
handwheel is directly proportional to the angular
movement of the handwheel.
Each device is adjusted to suit the exact
magnification of the periscope in which it is
incorporated.
The indicating scale dials are circular, arranged concentrically, and engraved in Arabic
numerals as follows:
1. Outer ring. Outside graduated 100 to 1,000
feet and inscribed Length of Target in Feet;
inside graduated 30 minutes to 85 degrees and
inscribed Course angle.
2. Intermediate ring. Outside and inside
graduated 2.2 to 110 and inscribed Range in 100
Yards.
3. Inner ring. Outside graduated 15 to 130,
feet and inscribed Height in Feet.
The range and course-angle finder consists
chiefly of three main assemblies:
99
1. Lower (split) objective lens and mount assembly (Figure 4-22).
3. Stadimeter housing assembly (Figure 4-24).
These three assemblies are not in contact with
each other for actuation in direct series. The
objective operating mechanism assembly and the
lower (split) objective lens and mount assembly
connect directly with each other. However, the
three assemblies are so connected by shafts and
couplings that they act as a unit. Three other
assemblies are placed between the objective
operating mechanism assembly and the stadimeter housing assembly for mechanical and optical
reasons. These three assemblies are:
1. First inner tube section assembly (Figure
4-27).
2. Eyepiece skeleton assembly (Figure 4-28).
3. Eyepiece box and miscellaneous assemblies
(Figure 4-29).
The stadimeter housing assembly contains
gearing which is connected to the internal mechanism of the eyepiece box (11, Figure 4-29) and
eyepiece skeleton assembly by a female tang
coupling (68, Figure 4-24) that projects upward
from the stadimeter housing assembly and engages on a milled tang at the lower end of the
stadimeter transmission shaft (22, Figure 4-27)
in the eyepiece box 11, Figure 4-29).
The stadimeter housing assembly, by means of
the stadimeter transmission shaft (22, Figure
4-27) and the stadimeter transmission shaft
coupling (14, Figure 4-23), is coupled with the
operating gear pinion shaft (13) of the objective
operating mechanism assembly. The stadimeter
transmission shaft (22, Figure 4-27) extends
through a bearing hole in the spider (2) where its
thrust is restrained by two thrust collars (4)
secured with taper pins (10). These two thrust
collars (4) restrain the axial thrust of the shaft
on either side of the spider (2), thereby restricting axial movement of the shaft. The eyepiece
skeleton (42, Figure 4-28) has a clearance hole
in its large shoulder flange to accommodate the
stadimeter transmission shaft (22, Figure 4-27).
The lower (split) objective lens and mount
assembly is secured to the objective operating
mechanism assembly by means of four stadimeter collimating screws (13, Figure 4-22). The
stadimeter housing assembly (Figure 4-24) is
secured to the eyepiece box (11, Figure 4-29) by
means of four stadimeter housing bolts (30, Figure 4-24).
4J2. Description of the lower (split) objective lens
and mount assembly. Figure 4-22 shows the
Ill. No.
Drawing Number
Num- ber Re- quired
Nomenclature
1
P-1158-1
1
Right mount half
2
P-1158-2
1
Left mount half
3
P-1158-9
4
Tension plugs
4
P-1158-10
4
Tension plug springs
5
P-1158-13
2
Half ring clamps
6
P-1158-13A
12
Variable thickness washers
7
P-1159-7
2
Large side clamps
8
P-1159-8
2
Small side clamps
9
P-1159-9
4
Mount keys
10
P-1179-25
12
Half ring clamp lockscrews,
11
P-1179-26
12
Large and small clamp lockscrews
12
P-1179-31
8
Tension plug spring lockscrews
13
P-1179-34
4
Stadimeter collimating screws
14
P-1179-34A
4
Washers for stadimeter collimating screws
15
P-1179-189
4
Mount dowel pins
16
P-1418-12A
2
Crown halves
17
P-1418-12B
2
Flint halves
18
P-1418-12C
6
0.001 inch tin foil, to separate the lower objective split lens halves
lower (split) objective lens and mount assembly.
All bubble numbers in Sections 4J2, 3, and 4
refer to Figure 4-22 unless otherwise specified.
a. Lower (split) objective lens. The lower
(split) objective lens is made of two optical
elements; one is a double convex crown element
(16) while the other is a concave plano flint element (17) separated with 0.001-inch tin foil (18)
forming an air-space doublet.
Both elements are split individually and when
assembled in the mount halves have an approximate gap of 0.055 inch between the split. The
lens halves are carried by the objective operating
mechanism to a maximum displacement of both
halves of 9/16 to 5/8 inch.
Each half is separated with three strips of
0.001-inch tin foil (18) equally spaced and placed
100
Figure 4-22. Lower (split) objective lens and mount assembly.
near the periphery. This provides spacing sufficiently uniform to keep color constant over the
outer surface where the lens halves are separated,
thereby preventing newton rings. Lenses of large
diameter cannot be cemented because of the difference in the thermal expansion coefficients of
crown and flint glasses.
The plano surface of the flint element rests
against the lower shoulder seat of each mount,
while the inner circumference is scraped to a true
bearing seat with the periphery of the lens doublet. The opposite corners of the split section of
the doublet halves are beveled at a 45 degrees angle.
These beveled faces are clamped sufficiently radially
by the scraped 45 degrees angle contact seats of the
large and small side clamps (7 and 8).
The split lens doublet of each assembled
mount is clamped snugly, without restricting the
movement of the lens under constant spring pressure applied to the tension plugs. Changes in the
relative position of the split halves of the doublet
caused by expansion and contraction of the lens
mount are sufficient to destroy its collimation.
Therefore, the angle of the beveled contact surfaces of the lens and their angular relation to the
movement of the tension plugs, centralizes the
split halves of the doublet against the 45 degrees angle
contact seats of the side clamps, thus maintaining
101
the proper, relation of the split lens doublet
halves.
b. Right and left mount halves. The right
and left mount halves (1 and 2) are made of
cast aluminum. Each is provided with eccentric
flanges with an offset of 0.197 inch from the original axis. The mounts are not a complete half
circle, as a part is cut away to provide clearance
for the attachment of large and small side clamps
(7 and 8) secured with lockscrews (11) to the
split faces of the mounts. The lens walls project
upward from the eccentric flange with a nominal
wall thickness. A narrow shoulder is provided
next to the bottom of the inner circumference
of the lens wall, to which the plano surface of
each split flint element is retained.
Each lens wall has two radial slotted openings
of appropriate length, separated at a 90 degrees angle
for the insertion of two tension plugs (3). These
are retained by tension plug springs (4) which
are secured with two lockscrews each (12).
Each eccentric flange has two elongated holes
to provide the necessary adjustment over the
inserted stadimeter collimating screws (13). The
outer face of each elongation is countersunk for
the stadimeter collimating screw washers (14).
The lower face of each eccentric has two key recesses for the mount keys (9). The elongations
and keys are parallel in each mount half. In
the right mount half (1) the elongations and
keys are located perpendicular to the split
of the lens halves. The inserted mount keys are a
sliding fit in keyways of the same perpendicular
location in the right mounting plate (5, Figure
4-23) of the objective operating mechanism assembly. This mount half can be adjusted at perpendicular plane to the split of the lens halves,
moving it away from the axis and increasing the
gap between the split lens halves, or moving it
toward the axis and decreasing the gap.
The left mount half (2) has the elongations and
keys located parallel to the split of the lens
halves. The inserted mount keys are a sliding fit
in keyways of the same parallel location in the
left mounting plate (5, Figure 4-23) of the objective operating mechanism assembly. This mount
half can be adjusted parallel to the split lens
halves, moving it to either side of the axis as is
necessary.
The split lens doublet halves are retained radially in the mount halves by the large and small
side clamps (7 and 8). The clamps are secured to
each side of the split faces of the mount with
lockscrews (11). The split lens doublet halves are
retained axially in the mount halves by the half
ring clamps (5). The clamps fit over the six variable thickness washers and are secured to the face
of each lens wall with six lockscrews (10).
Each mount is secured to each mounting plate
half (5, Figure 4-23) with two stadimeter collimating screws (13) and two dowel pins (15) after
collimation of the stadimeter.
e. Half ring clamps. The half ring clamps
(5) are made of brass tubing of one solid ring having an outside diameter of 4.900 inches which
conforms to the contour of the lens wall of the
mount halves (1 and 2). The inner circumference
is bored with a counterbore of shallow depth, its
counterbored diameter conforming to the inner
circumference of the lens wall of the mount
halves. The ring is chamfered at a 30 degrees angle from
the bore. The ring is split after machining with a
3/16-inch cutter, thus forming a half ring clamp
for each split lens doublet half. Each half ring
clamp has six equally spaced clearance holes for
lockscrews (10). These lockscrews screw into
tapped holes of each lens wall of the mount
halves. The half ring clamps are assembled to
the face of each lens wall of the mount halves (1
and 2) over six variable thickness washers (6).
The shoulder face of the counterbore fits snugly
against the shortest radius surface of the split
crown element of the doublet half. The adjustment of these half ring clamps is of sufficient
tension only to allow the tension plugs under
spring pressure to centralize the split lens doublet
halves against each beveled contact surface of
the large and small side clamps (7 and 8).
d. Large and small side clamps. The large
and small side clamps (7 and 8) are made of
phosphor bronze 0.125 inch thick. These clamps
are shaped to conform to each part of the split
contact faces of each mount half and are secured
with three lockscrews each (11). The lockscrews
are inserted into countersunk clearance holes in
the clamps and screwed into tapped holes in their
large and small split contact faces respectively.
Each side clamp projects 1/8 inch inward of the
inner circumference of the lens wall. The lower
102
face of this projecting section is beveled at a 45 degrees
angle and serves as a contact seat for the 45 degrees
angle beveled split face of the right and left side
of the split lens doublet halves. A 1/32-inch slot
of nominal depth in the beveled 45 degrees angle seat is
provided at the intersection of the crown and
flint elements, to allow clearance for the variance
of thermo coefficients of expansion of the crown
and flint elements. The large and small clamps
on each side of the split lens doublet halves retain the lens from radial displacement in the
mount halves (1 and 2).
e. Tension plugs. The four tension plugs (3)
are made of brass and are 0.625 inch in length
and 5/16 inch in width. Both ends of each tension
plug have the corners rounded off. Two tension
plugs are inserted in the radial slotted openings
of the lens wall of each mount half (1 and 2) and
fit loosely. The inner face of each tension plug
conforms to the contour of the periphery of the
split lens doublet halves. They are held against
the periphery of the lens doublet halves by the
spring pressure of tension plug springs (4)
mounted to the periphery of the lens walls of the
mount halves (1 and 2) and are secured with
lockscrews (12).
f. Tension plug springs. The tension plug
springs (4) are made of spring steel of 22 gage,
and blued. The contact surface of each spring is
bent with a 38-inch radius inward to contact the
tension plug (3) from the remaining contour of
the spring a distance of 0.093 inch. Each has two
clearance holes to accommodate lockscrews (12)
securing the two tension plug springs to the lens
wall of each mount half (1 and 2). These to screws are inserted into clearance holes in each
spring and screwed into the tapped holes in the
lens wall. The springs have sufficient applied tension on the tension plugs to centralize the split
lens doublet halves, with their contacting 45 degrees
beveled seats against the 45 degrees beveled seat faces
of the large and small side clamps (7 and 8).
4J3. Disassembly of the lower (split) objective
lens and mount assembly. The lower (split) objective lens and mount assembly is disassembled in
the following manner:
1. Remove the four stadimeter collimating
screws (13), holding each lower, (split) objective
lens and mount assembled half while unscrewing
the two collimating screws (13). Remove each
assembled lower (split) objective lens and mount
carefully, as the two dowel pins (15) are a push
fit in the mounting plates (5, Figure 4-23) of the
objective operating mechanism assembly.
2. Remove the two lockscrews (12) from the
two tension plug springs (4). These lockscrews
are unscrewed from tapped holes in the lens wall
of each mount half (1 and 2). Remove the four
tension plug springs (4) and the four tension
plugs (3).
3. Before removing the six lockscrews (10) of
each mount half, construct a wooden fixture with
six wire nails with reference marks. This is necessary for each mount half (1 and 2) because of the
variable thickness washers, and it enables the repairman to assemble them correctly.
4. Remove the six lockscrews (10) from each
of the half ring clamps (5). These lockscrews are
unscrewed from tapped holes in each lens wall of
the mount halves (1 and 2). Lift away the half
ring clamps and place the variable thickness
washers on the wire nails of each wooden fixture
in their respective order.
5. Remove the three lockscrews (11) from the
small side clamp (8). These lockscrews are unscrewed from tapped holes in the split center con
tact face of the small section of the mount half.
Remove the small side clamp.
6. Carefully remove the split lens doublet
half by pressing downward radially on the lens
next to the large side clamp (7) on the split center section rotating the lens out of the mount half.
This permits the lens halves to be freed. Handle
the split lens doublet half with lens tissue.
7. Place pencil marks on the periphery of the
split lens doublet halves and on the inner circumference of the mount half to provide a proper
reference for reassembly. Place the three strips
of 0.001-inch tin foil (18) in a small box to prevent damage or loss. Place the crown and flint
elements of this half to one side to prevent
scratches or breakage.
8. Follow the procedure stated in Steps 5, 6,
and 7 for the other mount half.
9. Remove the three lockscrews (11) from
each large side clamp (7) of both mount halves
103
(1 and 2). These lockscrews are unscrewed from
tapped holes in the split center contact face of
the large section of each mount half, removing
the large side clamps.
10. Check the lacquered split center flat sections of each split lens doublet half, and re-lacquer them if necessary. Slack lacquer is used
to prevent light from entering or escaping from
the split flat center section of the split lens doublet halves (16 and 17).
4J4. Reassembly of the lower (split) objective lens
and mount assembly. The lower (split) objective lens and mount assembly is reassembled in
the following manner:
1. Assemble the large side clamps (7) to their
respective mount halves. Insert and secure the
lockscrews (11), screwing them into the tapped
holes of the large section of the split contact surfaces of each mount half.
2. Clean the crown and flint elements (16 and
17) of the split lens doublet halves with clean lens
tissue. All surface dirt, grease, or foreign matter
must be removed with alcohol. Wipe each surface
dry with a clean untouched lens cloth or lens tissue. Specks of dirt which have a tendency to adhere may be removed with a sable brush which
has been cleaned with ether. A vacuum brush
with ether is also effective. All lens elements must
be cleaned in the same careful manner. A rubber
air bulb removes most of the surface dust.
3. Place the three strips of 0.001-inch tin foil
(18) at three equally spaced places near the periphery, to separate the crown and flint elements.
The strips of tin foil are placed on the concave
surface of the flint element, and the crown element having the longest radius is place on the
three strips of tin foil.
4. Holding the split lens do let halves
(crown and flint) together with lens tissue, place
them in the mount half (1), with the large side
clamp (7) in place. Press downward from the split
flat center section on the opposite side until the
lens is rotated up tight against the 45 degrees angle contact seat face of the large side clamp.
5. Proceed to fit the small side clamp (8)
until the lockscrews (11) inserted in the tapped
holes in the small section of the split contact face
of the mount half are within 1/8-turn of being
tight. The lapped 45 degrees angle contact surface of the
small side clamp (8) to the 45 degrees angle contact
beveled face of the split lens doublet halves
should be fitted to allow only 1/8-turn of the lockscrews (11), to prevent angular movement, and
to allow sufficient clamping without placing any
strain in the crown and flint elements.
6. Follow the procedure stated in Steps 4 and
5 for the mount half (2).
7. Place the six variable thickness washers
(6) from the reference fixture at their respective
places on the face of the lens wall of the mount
half (1). Place the half ring clamp (5) over the
variable thickness washers (6) and line up the
holes of the half ring clamp and the washers.
Insert the six lockscrews (10) through the clearance holes in the half ring clamp and the washers,
and screw them into tapped holes in the lens wall
of the mount half. Using a 0.001-inch piece of
shim stock, tighten the lockscrews maintaining
0.001-inch clearance between the half ring clamp
and the face of the crown element. The half
ring clamp prevents axial displacement of the
split lens doublet halves, and is tightened sufficiently that it does not restrict the free movement of the tension plugs (3). A strain testing
device using polarized light should be used to
ensure that there is no strain in the assembled
lens element.
8. Follow the procedure stated in Step 6, for
the opposite mount half (2).
9. Insert the four tension plugs (3) in the two
radial slotted openings of each mount half, placing the concave surface of the tension plug to
ward the periphery of the split lens doublet
halves. Assemble the tension plug springs (4)
securing each with two lockscrews (12) placing
the tension plugs (3) under spring pressure. The
lockscrews are inserted into clearance holes in
the tension plug spring and screwed into tapped
holes in the lens wall of each mount half.
10. Assemble both mount halves (1 and 2) to
the mounting plates (5, Figure 4-23) after the 90 degrees
rotation is adjusted and checked.
4J5. Description of the objective operating mechanism assembly. This mechanism consists of the
necessary parts which transmit the displacement of the lower (split) objective lens and
mount assembly, and is described in the following manner: Figure 4-23 shows the objective
operating mechanism assembly. All bubble numbers in Section 4J5, 6, and 7 refer to Figure 4-23
unless otherwise specified.
Ill. No.
Drawing Number
Num- ber Re- quired
Nomenclature
1
P-1156-1
1
Operating gear
2
P-1156-2
1
Track sleeve
3
P-1156-3
1
Sliding track
4
P-1156-4
2
Cam shoes
5
P-1158-3
2
Mounting plates
6
P-1158-5
1
Detent pawl spring
7
P-1158-6
2
Detent pawls
8
P-1158-7
1
Detent pawl rest
9
P-1158-8(a)
2
Long detent pawl rest lockscrews
10
P-1158-8(b)
2
Short detent pawl rest lockscrews
11
P-1158-12
2
Sliding track lock rings
12
P-1159-1
1
Operating gear pinion
13
P-1159-2
1
Operating gear pinion shaft
14
P-1159-3
1
Stadimeter transmission shaft coupling
15
P-1159-4
2
Mounting plate guide key with integral shafts
16
P-1159-5
2
Detent pawl shafts
17
P-1159-6
2
Mounting plate guide keys
18
P-1159-10
2
Mounting plate guides
19
P-1163-4
1
Operating gear stop
20
P-1163-5
2
Maximum displacement stop and observation position stop
21
P-1172-15
1
Operating gear pinion key
22
P-1179-23
4
Coupling sleeve lockscrews (upper end)
23
P-1179-24
4
First inner tube section upper end coupling lockscrews
24
P-1179-27
2
Operating gear pinion lock screws
25
P-1179-28
4
Operating gear retaining ring lockscrews
26
P-1179-29
6
Detent pawl spring lockscrews
27
P-1179-30
15
Coupling sleeve lockscrews (lower end)
28
P-1179-32
2
Mounting plate guide key lockscrews
29
P-1179-33
6
Mounting plate guide lockscrews
30
P-1179-73
6
Operating gear stop, observation position stop and maximum displacement stop lockscrews
31
P-1179-177
2
Mounting plate guide key shaft taper pins
32
P-1179-178
2
Detent pawl shaft taper pins
33
P-1179-179
2
Stadimeter transmission shaft coupling taper pins
34
P-1205-5
1
Coupling sleeve
35
P-1205-8
1
Operating gear retaining ring
36
P-1310-15
1
Sliding track lock ring lockscrew
105
a. Sliding track. The sliding track (3) is
made of cast phosphor bronze and is 12.574
inches in length. It is machined cylindrical, with
a large shoulder flange of nominal thickness at
the upper part. Its internal diameter is machined
for light transmission and has anti-reflection
threads throughout.
A brass plate spacer 1/16 inch thick and 1/4 inch
wide is inserted and soldered in the slots cut
directly in the centerline in each side of the bore
of the large shoulder flange. The spacer when
assembled is flush with the face of the large
shoulder flange. It prevents stray light from
entering the gap between the two split lens
doublet halves of the lower (split) objective
lens (16 and 17, Figure 4-22).
Two longitudinal T-slots are milled parallel
to the horizontal centerline, at an appropriate
center distance from the vertical centerline on
each side; there are two more 180 degrees apart on
the opposite side in the large shoulder flange.
These longitudinal T-slots project inward horizontally on each side an appropriate distance,
to correspond to an appropriate center distance from the vertical centerline, to receive
two mounting plate guide keys with integral
shafts (15) and mounting plate guide keys (17).
The large shoulder flange face has two shallow
recesses 1 5/16 inches wide located an appropriate
distance from the horizontal centerline, and parallel with it. The remaining part of the face
serves as a bearing for the lower surfaces of two
mounting plates (5) retained with two mounting
plate guides (18). The mounting plate guides are
mounted parallel to the horizontal centerline, on
opposite sides, and are secured with three lockscrews (29) each. The mounting plates (5) are
moved against each other over the bearing faces
of the large shoulder flange of this sliding track
with their sides under the mounting plate guides
(18).
The sliding track has a cylindrical tube section of about 1 foot below the large shoulder
flange. Next to the large shoulder flange is a
small shoulder to receive the small counterbored
section in the operating gear (1). Sections of the
external diameter are undercut to provide only
the necessary bearing surface for the operating
gear (1) and the track sleeve (2) over this tube
section. The lower part is threaded a short distance to receive two lock rings (11).
b. Operating gear. The operating gear (1)
is made of cast phosphor bronze and is 2.687
inches in length. It is machined cylindrical with
a large shoulder flange in the upper part. It is
counterbored in the center part of the bore to
provide only sufficient bearing surface over the
bearing section shoulders of the sliding track (3).
The large shoulder flange is counterbored a shallow depth, and is a sliding fit over the small
shoulder next to the shoulder flange of the sliding
track (3).
The large shoulder flange has two cam grooves
of appropriate depth and width in its face, which
extend 1 degree beyond the vertical centerline. This 1 degree
extension provides sufficient clearance for the
cam shoes (4) which have centers in the vertical
centerline of the operating gear (1) at zero displacement of the lower (split) objective lens (16
and 17, Figure 4-22). Using the vertical centerline as a reference, these two cam grooves are
machined 153 degrees circumferentially on opposite
sides starting 180 degrees apart.
The operating gear fits over the bearings of the
sliding track (3) with its large shoulder flange
making a metal-to-metal bearing contact with
the lower face of the sliding track large shoulder
flange. It is retained from axial displacement on
the sliding track by an operating gear retaining
ring (35) which is secured with four lockscrews
(25).
The periphery section below the large shoulder
flange has two shoulders, one near the center
inch wide and the other at the lower part. The
center shoulder has 160 teeth of 32 pitch cut
around its periphery, which engage with an assembled operating gear pinion (12) that projects
upward from the bearing projection of the track
sleeve (2) on the operating gear pinion shaft (13).
The operating gear stop (19) is assembled to
the lower shoulder of the operating gear (1) so
that its centerline is 22 degrees from the reference line,
and is secured with two lockscrews (30) in tapped
holes in the lower shoulder of the operating gear
(1). When the cam shoes (4) are at the limit of
their travel, the operating gear is reversed 0.125
inch. At this position of the operating gear (1),
a line is scribed on the operating gear retaining
ring (35). At this line, the maximum displacement stop (20) is secured to the retaining ring
with two lockscrews (30). The scribed line is the
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point of contact of the operating gear stop (19)
and the maximum displacement stop (20).
The observation position stop (20) is secured
during the process of collimation. (Refer to Section 4V11 Step, 25.)
c. Track sleeve. The track sleeve (2) is made
of cast phosphor bronze and is 11.827 inches in
length. The upper part has a cast rectangular
bearing projection that extends upward from
the shoulder flange, and is provided with a
reamed hole in its center axis which serves as a
bearing for the operating gear pinion shaft (13).
The main body is machined cylindrical with
two cast hinge projections located 180 degrees apart,
a short distance from the upper shoulder flange.
One raised section of appropriate size, at a perpendicular plane to the two hinge projections,
serves as a mount for the detent pawl spring (6).
A circumferential slot 128 degrees long and 3/8 inch wide
is located in the center of this raised section, with
the slot running 64 degrees on each side of the vertical
centerline. This circumferential slot receives the
detent pawl rest (8) attached to the sliding track
(3) with two long and short lockscrews (9 and
10), secured in tapped holes in the sliding track.
The hinge projections have a 1/4-inch slot
through their center located in the same plane
as the 128 degrees circumferential slot, and reamed
holes perpendicular to this slot through the center of the hinge projections on both sides of the
1/4-inch slot. The hinge projections receive the
hinge section of two detent pawls (7), with two
detent pawl shafts (16) forming the hinge pins,
secured with a taper pin (32) each.
The track sleeve is bored and ground with
bearings in the upper and lower internal part, a
sliding fit over the bearings on the periphery of
the sliding track tube section (3). One inch from
the upper face it has a counterbore of shallow
depth a distance of 6 3/8 inches, allowing a 1-inch
bearing in the lower part near the lower end and
also in the upper part. The track sleeve is counterbored below the lower bearing a distance of
2.187 inches, to accommodate two sliding track
lock rings (11) that secure the sliding track
axially. It serves as an alignment support section
also with the lower end threaded a 3/4-inch distance, to receive the alignment support section
and the threaded periphery of the first inner tube
section upper end coupling (11, Figure 2-27) and
is secured with four lockscrews (23). These lockscrews are inserted into countersunk clearance
holes in the lower part of the track sleeve (2)
and screwed into tapped holes in the upper alignment support section of the first inner tube section upper end coupling (11).
The lower external part of the track sleeve (2)
has a cylindrical shoulder flange, which projects
upward with a cored inner wall 1 1/2 inches in
length. This wall section is turned to serve as an
alignment support section or the lower part of
the lower (split) objective lens coupling sleeve
(34) fitting up to a shoulder in the lower part.
The coupling sleeve is secured to this alignment
support section with 15 lockscrews (27). These
lockscrews are inserted into countersunk clearance holes in the coupling sleeve and screwed
into tapped holes in the alignment support section. A section of the cored section is solid with a
reamed hole, having its centerline in the same
axis as the extended projection of the upper cast
bearing flange, located 180 degrees opposite to the centerline of the raised mount and the radial slot
for the detent pawl spring; this reamed hole
serves as a bearing for the operating gear pinion
shaft (13).
Four tape slots are provided in the bearing
flange of the track sleeve (2), two opposite the
others, for the prism tilt and change of power
shifting wire tapes (38, Figure 4-28). An air line
slot is provided at assembly at a perpendicular
plane to the tape slots, for the air line section
(29, Figure 4-21) extending downward from the
second inner tube section (22).
d. Mounting plates. The two mounting
plate halves left and right (5) are made of cast
phosphor bronze and are 1/2 inch wide. Each is
of eccentric design with the inner circumference
0.197 inch offset from the outer diameter, and
is bored for light transmission. The design of
each complies to the eccentric flange and lower
face of the right and left mount halves (1 and 2,
Figure 4-22). Each half has a 50 degrees minor chord
section removed from the outer circumference
and is provided with a narrow shoulder to slide
on the bearing face of the sliding track large
shoulder flange under the parallel shoulder of
the mount guide (18) which is secured with three
107
lockscrews (29) in the large shoulder flange of the
sliding track (3).
The mounting plates are assembled to the
bearing faces of the large shoulder flange of the
sliding track (3) for operation with the operating
gear (1) in the following manner: The large part
of the right mounting plate has a reamed hole to
receive the integral long shaft section of the
mounting plate guide key (15) inserted from the
lower face, and is secured with a taper pin (31)
from the periphery of this part. The T design of
the mounting plate guide fits in the elongated
T-slot in the sliding track large shoulder flange.
The integral stub shaft located in the lower part
of the mounting plate guide key (15)fits into the
reamed hole in the cam shoe (4) located in the
cam groove of the operating gear (1) to provide
for operation of this half.
The narrow eccentric part of this mounting
plate half located on the opposite side, has a
tapped hole to receive the lockscrew (28). This
lockscrew is inserted into the countersunk clearance hole in the mounting plate guide key (17)
and screwed into the tapped hole in this narrow
eccentric part. The mount guide keys (15 and
17) located in the sliding track large shoulder
flange elongated T-slots provide parallel guidance for this mounting plate half.
The upper face of this mounting plate has two
horizontal keyways at a perpendicular plane to
vertical movement of this mounting plate to receive the two inserted mount keys (9) of the
right mount half (1, Figure 4-22) a sliding fit in
the keyways. These keyways provide a positive
movement in two directions of the axis, INWARD and OUTWARD, for collimation of the
right half of the lower (split) objective lens and
mount assembly. This mounting plate half has
two tapped holes to receive the stadimeter collimating screws (13) securing the above assembled
lens half also with two drilled holes for two dowel
pins (15, Figure 4-22) after collimation. The
dowel pins provide the factory collimation setting of this collimated lens half.
The upper face of the left mounting plate has
one vertical keyway located in the same plane as
its movement, to receive the two inserted mount
keys (9, Figure 4-22) of this mounting plate half
(2) a sliding fit in the keyway. This keyway provides a positive movement in two directions parallel
to the vertical centerline, INWARD and
OUTWARD of the horizontal centerline, for collimation of this mounting plate half.
The left mounting plate half is assembled and
secured to the sliding track (3) and operates in
similar manner in the opposite direction with the
use of the second cam groove of the operating
gear (1).
e. Mounting plate guide keys and integral
shafts. The two mounting plate guide keys and
integral shafts (15) are made of monel metal and
are 1.031 inches in length. The long shaft section
is integral with the milled T-shaped section. This
shaft section fits into each reamed hole in the
large part of each eccentric mounting plate and
is secured with a taper pin (31). The T-shaped
section is 3/8 inch in length and is a sliding fit
in the elongated T-slots on opposite sides in the
sliding track large shoulder flange.
The stub shaft section is an integral part of
the lower part of the T-shaped section and fits
into the reamed hole in the cam shoe (4) assembled in the cam groove of the operating gear.
The cam shoes on the mounting plate guide keys
and integral shafts operating in the cam grooves
in the operating gear (1) displace the mounting
plate halves laterally.
f. Mounting plate guide keys. The two
mounting plate guide keys (17) are made of
monel metal and are 3/8 inch in length. They are
milled of a T-shape with a countersunk clearance
hole in their axis for a lockscrew (28). The lockscrew secures them to the narrow eccentric
part of the eccentric mounting plate, extending
into the tapped hole in this narrow eccentric
part. These guide keys are a sliding fit in
the elongated T-slots in the sliding track large
shoulder flange and by means of the operating
guide keys (15) provide a parallel guidance to
the mounting plate halves (5) which carry the
lower (split) objective lens and mount assembly
halves (Figure 4-22) in the same vertical plane
for displacement from minimum to maximum
displacement and vice versa.
g. Mounting plate guides. The mounting
plate guides (18) are made of monel metal and
are 1.750 inches in length. It is a step design
with the narrow shoulder having a nominal fit
on the shoulder section of each mounting plate
108
half (5). They are held to the large shoulder
flange face of the sliding track (3) with three
lockscrews (29) each. These lockscrews are inserted into countersunk clearance holes in the
mounting plate guides (18) and screwed into
three tapped holes in opposite sides of the sliding
track large shoulder flange (3). These guides
allow free movement to each mounting plate half
and retain them axially.
h. Cam shoes. The two cam shoes (4) are
made of hardened drill rod steel and are 5/16 inch
in length. The ends are rounded off to conform
to the width of 0.218 inch. A reamed hole in their
axis accommodates the integral stub shaft section of the mounting plate guide keys and integral shafts (15). The cam shoes are a sliding fit
in each cam groove in the operating gear large
shoulder flange (1). The cam shoes operate the
mounting plate guide keys (15)-for displacement
of the assembled lower (split) objective lens and
mount assembly halves (Figure 4-22).
i. Operating gear retaining ring. The operating gear retaining ring (35) is made of old
rolled steel and is 1/2 inch in width. It is cylindrical with a nominal wall thickness, and fits over
the sliding track tube section (3) up to the lower
face of the operating gear (1) and is secured with
four lockscrews (25). These lockscrews are
inserted into countersunk clearance holes in
the retaining ring and screwed into tapped
holes in the sliding track (3). It serves to retain
the operating gear (1) axially and also serves
as a stationary support for the maximum
displacement and observation position stops (20)
secured with two lockscrews (30).
j. Maximum displacement stop. The maximum displacement stop (20) is made of cold
rolled steel 3/4 inch wide and 7/8 inch long. It is a
step radius design, with the seat of the stop conforming to the contour of the operating gear
retaining ring (35) and secured to it with two
lockscrews (30). These lockscrews are inserted
in countersunk clearance holes in the thick section of the stop and screwed into tapped holes in
the retaining ring (35) and the sliding track. The
radius step projects over the lower shoulder of
the operating gear with sufficient clearance.
The maximum displacement stop serves to relieve the torque from the two cam shoes (4) in
the ends of the cam grooves in the operating
gear (1) for the necessary additional torque required to rotate the sliding track (3) simultaneously with the operating gear (1) for the 90 degrees
rotation from the range position to the course
angle position. It also serves to overcome the
locking device of the sliding track (3), namely,
the detent pawl (7) engaged in the 90 degrees V-groove
in the detent pawl rest (8).
k. Observation position stop. The observation position stop (20) is identical to the maximum displacement stop, and is located on the
retaining ring (35) during collimation. It serves
to relieve the torque from the two cam shoes (4)
in the ends of the cam grooves in the operating
gear (1) for the necessary additional torque required to rotate the sliding track (3) simultaneously with the operating gear (1) for the 90 degrees
rotation from the course angle position back to
the range position. It is fitted during collimation
(refer to Section 4V11 Step 25) to restrict the
movement of the lens halves to zero displacement, that is, to form a single image.
l. Operating gear stop. The operating gear
stop (19) is of similar design and material to the
maximum displacement and observation position
stops (20). The seat of the stop conforms to the
contour of the lower shoulder of the operating
gear (1) and is secured with two lockscrews (30).
These lockscrews are inserted into countersunk
clearance holes in the thick section of the stop
and screwed into tapped holes in the lower
shoulder of the operating gear. The radius step
projects over the operating gear retaining ring
(35) with sufficient clearance. This stop is secured to the operating gear with its centerline
located 22 degrees from the reference line of the cam
groove. This allows sufficient movement of the
operating gear for minimum and maximum displacement of the lower (split) objective lens.
This stop overlaps the maximum displacement
stop (20) for clockwise rotation to carry the sliding track (3) simultaneously with the operating
gear (1) through the 90 degrees rotation from the range
position to the course angle position. It overlaps
the observation position stop (20) for the counterclockwise rotation to carry the sliding track (3)
simultaneously with the operating gear (1)
through the 90 degrees rotation from the course angle
position back to the range position.
m. Operating, gear pinion. The operating
gear pinion (12) is made of phosphor bronze and
109
is 1.531 inches in length. It is cylindrical in design
with a large hub section in the upper part which
is filleted at a radius of 1.750 inches in a distance
of 5/16 inch to conform to the circumference of the
gear cutter used in cutting the teeth in the lower
large diameter. The large diameter of the pinion
section has 20 teeth of 32 diametral pitch, cut in
a pinion section 0.718 inch long. The lower part of
this pinion section is undercut to the root of the
gear teeth and chamfered.
The axis is provided with a reamed hole, a
push fit over the upper part of the operating
gear pinion shaft (13). The reamed hole has an
undercut groove 1/16 inch wide located above the
upper end of the pinion section, to serve as a relief for the insertion of a keyseat 0.063 inch wide
and 0.036 inch deep. This keyseat allows the
pinion to slide over the inserted woodruff key
(21) in the upper part of the operating gear
pinion shaft (13). The hub section is provided
with two tapped holes directly on opposite sides
for two lockscrews (24). These lockscrews are
inserted in tapped holes in the pinion and extend
into spotted recesses in the operating gear pinion
shaft (13) at assembly to secure the pinion.
The operating gear pinion teeth mesh with the
teeth in the operating gear (1) for its operation.
n. Operating gear pinion shaft. The operating gear pinion shaft (13) is made of cold
rolled steel rod and is 14.625 inches in length and
5/16 inch in diameter. It is provided with a woodruff keyseat located near the upper end, for a
number 10 woodruff key (21). The operating gear
pinion (12) with a keyseat is a push fit on the
upper part of this shaft and is secured with two
lockscrews (24). This shaft fits through the
reamed hole in the cast projection located in the
upper part of the track sleeve (2) and the reamed
hole in the solid section in the cored alignment
support section of the lower part.
The lower part of the shaft receives the upper
part of the stadimeter transmission shaft coupling (14) secured with a taper pin (33) during
collimation.
o. Stadimeter transmission shaft coupling. The stadimeter transmission shaft coupling (14) is made of phosphor bronze and is 1.812
inches in length. It is 5/8 inch in diameter, with
the axis provided with two reamed holes. The
upper part is reamed to fit on the lower part of
the operating gear pinion shaft (13) and is secured with a taper pin (33). The lower part is
reamed to receive the upper part of the stadimeter transmission shaft (22, Figure 4-27) and is
secured with a taper pin (33) during collimation.
The lower part is provided with three irregular
tapped holes at assembly for the insertion of
8-36 setscrews used primarily to secure the coupling to the stadimeter transmission shaft (22,
Figure 4-27) during collimation, and the taper
pin provision is made upon completion of
collimation.
p. Detent pawl rest. The detent pawl rest
(8) is made of tool steel and is 1 5/8 inches in
length. Its bottom face conforms to the contour
of the sliding track periphery (3), while the upper
faces on each side of the horizontal centerline
are beveled to 27 1/2 degrees. It is a sliding fit in the
milled 128 degrees circumferential slot in the track.
sleeve (2). A 90 degrees V-groove is provided in the
horizontal centerline to a depth of 0.407 inch,
for the engagement of the detent pawls (7) for
the range and course angle positions. The opposite ends of the detent pawl rest are finished to
approximately 38 degrees or 19 degrees on each side of the
horizontal centerline to contact each end in the
128 degrees circumferential slot, when the operating
gear (1) and the sliding track (3) have rotated
90 degrees. The opposite ends of the detent pawl rest
are finished off at assembly and the collimation
procedure of the 90 degrees rotation. A dowel pin of a
body fit is inserted in the hole in the center of the
90 degrees V-groove and fitting into the snug hole in
the sliding track, is inserted for proper location
of the four tapped holes. The detent pawl rest is
secured to the periphery of the sliding track (3)
through the circumferential slot with two long
and short lockscrews (9 and 10). These lockscrews are inserted into countersunk clearance
holes in the detent pawl rest (8) and screwed into
tapped holes of the sliding track (3).
q. Detent pawls. The detent pawls (7) are
made of tool steel and are 2 1/2 inches in length.
The arms of each detent pawl are 1/4 inch wide
and 5/32 inch thick. The detent section is enlarged to 3/8 inch in width and inclined at an
angle of 22 degrees of the arm section. Its engaging
detent section of 90 degrees engages in the 90 degrees V-groove
in the detent pawl rest (8), to maintain it at the
90 degrees rotation position under spring tension.
110
The lower part of the detent pawl arm section
is enlarged inward, thus forming a partial circle
of 7/16-inch diameter, with a reamed hole to receive the detent pawl shaft (16). The circle section fits in the milled slot between both hinge
projections, with the shaft inserted in the reamed
holes in the hinge projections and the circular
section. Each of the two shafts is secured with a
taper pin (32) in the lower hinge projections.
The detent pawls for the range and course
angle positions are retained in the 90 degrees V-groove
under spring pressure by the detent pawl spring
secured to the raised mount section on each side
of the 128 degrees circumferential slot with six lockscrews (26).
r. Detent pawl shafts. The detent pawl
shafts (16) are made of cold rolled steel and are
0.812 inch in length. These shafts fit into reamed
holes in the two sets of hinge projections of the
track sleeve (3) and are secured with a taper pin
(32) after assembly. These shafts serve as a pivot
pin on which the circular section of the detent
pawls pivot for engagement and disengagement
in the detent pawl rest (8).
s. Detent pawl spring. The detent pawl
spring (6) is made of 17-gage blued spring steel.
The center part is 1 inch in width, to extend over
the width of the raised mount section on each
side of the circumferential slot. Each side of the
spring starting from 3/4 inch of the center is filleted to 14 inch width, a proportional amount on
each side. The spring is bent from the filleted
point inward to a radius of 1.500 inch, on each
side with an outward radius bend of 3/16 inch.
It is oil hardened in this form, and when assembled it overlaps to contact the 22 degrees angle outer
section of both detents. It is secured on this section of the detent pawls (7) to the raised mounts
on each side of the circumferential slot with three
lockscrews (26). These lockscrews are inserted in
clearance holes in this spring and screwed into
tapped holes in the raised mount on opposite
sides of the 128 degrees circumferential slot.
t. Sliding track lock rings. The two sliding
track lock rings (11) are made of cast phosphor
bronze 5/16 inch wide. The rings are cylindrical,
and are a sliding fit in the counterbore of the
track sleeve. The inner surface is threaded to
screw can the threaded periphery of the sliding
track (3). These rings preserve the axial thrust
clearance of the sliding track (3) in the track
sleeve (2). Each is provided with opposite slots
in the lower side face for insertion of a special
wrench. The lower of the two lock rings (11) is
secured against the upper by a lockscrew (36).
This lockscrew screws into the tapped hole in
the threaded intersection of the lower face of the
lock ring and the sliding track, and thus prevents
axial displacement of the sliding track (3) in the
track sleeve (2).
u. Coupling sleeve. The coupling sleeve (34)
is made of brass tubing material 14.875 inches in
length. The inner and outer diameters of this
coupling sleeve are uniform throughout its length.
This sleeve section forms the outer wall to enclose the lower (split) objective lens and mount
assembly (Figure 4-22) and the objective operating mechanism assembly. It also connects the
upper telescope system assembly Part II (Figure 4-21) with the lower main telescope system.
Connection is made after primary and final collimation of the periscope.
The upper part has an internal threaded section 1 1/4 inches in length to screw on the threaded
periphery and lower alignment support section
of the second inner tube section lower end coupling (26, Figure 4-21) and is secured with four
lockscrews (22). These lockscrews are inserted in,
countersunk clearance holes in the upper part
of the coupling sleeve (34) and screwed into
tapped holes in the lower alignment support
section of the second inner tube section lower end
coupling (26, Figure 4-21).
The inner wall is provided with an 11-inch
axial recess groove with a 3/4-inch radius. This
axial recess groove starts at the lower end of
the coupling sleeve. The center of the radius is
located 19 degrees 30' from the horizontal centerline of the prism tilt shifting wire tape slots. The
radius is cut to a depth of 0.050 inch in the
inner wall. This axial recess groove provides
clearance for the operating gear pinion (12)
which is necessary to permit the lower telescope
system to be pulled axially clear of the coupling
sleeve for disassembly or vice versa.
Four vertical tape slots are provided in the
outer circumference, two opposite the others for
the entire length, for the prism tilt and change
of power shifting wire tapes (38, Figure 4-28). An
air line slot is provided its entire length at a
111
perpendicular plane to the tape slots for the air line
section (29, Figure 4-21) extending downward
from the second inner tube section (22).
The lower part is a push fit over the alignment
support section of the lower shoulder flange of the
track sleeve (2) and is secured with 15 lockscrews
(27). These lockscrews are inserted into countersunk clearance holes in the lower part of the
coupling sleeve and screwed into tapped holes in
the alignment support section of the lower shoulder flange of the track sleeve (2).
4-16. Disassembly of the objective operating
mechanism assembly. The objective operating
mechanism is disassembled in the following
manner:
1. Remove the six lockscrews (26) from the
detent pawl spring (6). These lockscrews are
unscrewed from tapped holes in the raised
mount of the track sleeve (2). Remove the detent
pawl spring.
2. Remove the taper pins (32) from the
lower two hinge projection sets of the track
sleeve (2) to free the detent pawl shafts (16).
Drive these shafts upward through the clearance
hole in the upper shoulder flange of the track
sleeve, removing the detent pawl shafts (16)
and the detent pawls (7).
3. Remove the two long and two short lockscrews (9 and 10) from the detent pawl rest (8)
and remove the detent pawl rest from its insertion in the circumferential slot of the track
sleeve (2). The lockscrews are unscrewed from
tapped holes in the periphery wall of the sliding
track (3).
4. Remove the lockscrew (36) from the
tapped hole in the threaded intersection of the
lower face of the lower sliding track lock ring
(11) and the sliding track (3). Unscrew the lower
lock ring (11) which is a tap fit, using a special
wrench. Then unscrew the upper of the two lock
rings (11) in the same manner.
5. Remove the sliding track (3) from the
track sleeve (2). At the same time, remove the
assembled operating gear pinion (12) and shaft
(13). The operating gear pinion and shaft must
be removed with the sliding track to prevent
damage to these parts.
6. Remove the two lockscrews (24) from
opposite sides of the operating gear pinion (12).
Pull the operating gear pinion off the operating
gear pinion shaft (13). The woodruff key (21)
remains in the shaft.
7. Remove the two lockscrews (30) from the
maximum displacement stop (20). These lockscrews are unscrewed from tapped holes in the
operating gear retaining ring (35) and the
sliding track (3).
8. Remove the two lockscrews (30) of shorter
length from the observation position stop (20).
These lockscrews are unscrewed from tapped
holes in the operating gear retaining ring (35).
9. Remove the four lockscrews (25) from the
operating gear retaining ring (35). These lockscrews are unscrewed from tapped holes in the
sliding track (3). Remove the retaining ring.
10. Remove the operating gear (1) from the
tube section of the sliding track (3).
11. Remove the two lockscrews (30) from the
operating gear stop (19). These lockscrews are
unscrewed from tapped holes in the lower
shoulder of the operating gear (1).
12. Remove the two cam shoes (4) from the
stub shaft of the two mounting plate guide keys
and integral shafts (15), or lift them from the
cam grooves in the operating gear (1).
13. Remove the two lockscrews (29) from
each, of the two mounting plate guides (18).
These lockscrews are unscrewed from tapped
holes in the large shoulder flange on opposite
sides of the sliding track (3). Remove the two
mounting plate guides.
14. Remove the two lockscrews (28) from the
two mounting plate guide keys (17). These
lockscrews are unscrewed from tapped holes in
the narrow eccentric section of the two mounting
plate halves (5). Remove the mounting plate
guide keys from the T-slots on opposite sides
of the sliding track (3).
15. Carefully slide out each mounting plate
half (5) with the mounting plate guide keys and
integral shafts (15), moving them outward in
opposite directions from the T-slots on opposite
sides of the sliding track (3).
112
16. Remove the two taper pins (31) from the
large eccentric section of the two mounting plate
halves (5). Drive out the two mounting plate
guide keys and integral shafts (15) from both
mounting plate halves.
4J7. Reassembly of the objective operating
mechanism assembly. The objective operating
mechanism is reassembled in the following
manner:
1. Apply Lubricate No. 110 lightly to all
rotating parts as the reassembly procedure is
followed.
2. Assemble the mounting plate guide keys
and integral shafts (15) in the reamed holes in the
large eccentric art of the two mounting plate
halves (5) checking their corresponding reference
marks for proper assembly. The long section of
the integral shaft sections is inserted from the
lower face. Each is secured with a taper pin (31).
3. Stand the sliding track (3) in a vertical
position resting it on its lower face. Place one
and then the other of the two mounting plate
halves on the large shoulder flange face of the
sliding track (3). Carefully slide the mounting
guide keys of the assembled integral shafts into
the elongated T-slots in opposite directions, noting the reference marks for correct reassembly.
4. Assemble one and then the other of the
mounting plate guide keys (17) in the elongated
T-slots on opposite sides of the sliding track
large shoulder flange face (3). Secure each with a
lockscrew (28) screwing them into the tapped
holes in the narrow eccentric part of the two
mounting plate halves (5).
5. Place one and then the other of the two
mounting plate guides (18) over the side shoulder
of each mounting plate half (5), noting their
reference marks on the sliding track large
shoulder flange face (3). Secure each with three
lockscrews (29) screwing them into tapped holes
in the large shoulder flange on opposite sides.
The mounting plate guides are placed 180 degrees
apart.
6. Place the two cam shoes (4) on the two
mounting plate guide keys and integral stub
shafts (15), placing the thinner wall of the cam
shoe outward on each side.
7. Place the operating gear (1) over the
tube section of the sliding track (3). The upper
face of the operating gear large shoulder flange
contacts the lower face of the sliding track
large shoulder flange, and the two cam shoes
(4) are fitted into the cam grooves in the operating gear (1). The proper position of the operating
gear (1) for its contact with the sliding track
shoulder large flange (3) is obtained from corresponding reference marks on the sliding track.
8. Place the operating gear retaining ring (35)
on the tube section of the sliding track (3).
Check to ascertain that the 10 degrees rotation scribe
lines coincide with similar scribe lines on the
operating gear shoulder, and that lockscrew
holes coincide. Secure the retaining ring with
four lockscrews (25) which screw into tapped,
holes in the sliding track (3).
9. Assemble the operating gear stop (19) to
the operating gear lower shoulder section and
secure it with two lockscrews (30). These lockscrews are screwed into tapped holes in this
lower shoulder section.
10. To assemble the maximum displacement
stop (20) to the retaining ring (35), first rotate
the operating gear (1) until the cam shoes (4)
are at the limit of their travel; scribe a line on
the operating gear lower shoulder section and the
retaining ring (35). Reverse the operating gear
0.125 inch and note the tapped holes in the
retaining ring (35). Secure this stop with two
lockscrews (30) screwing them into the tapped
holes in the retaining ring (35) and the sliding
track (3).
11. The observation position stop (20) is
located and secured to the retaining ring (35)
during the procedure of collimation. (Refer to
Section 4Vll, Step 25.)
12. Place the operating gear pinion (12) on
the operating gear pinion shaft (13) sliding it
over the inserted woodruff key (21) located in
the upper part of this shaft. Secure the pinion
with two lockscrews (24), screwing them into
tapped holes in opposite sides of the pinion and
into spotted recesses in the shaft.
13. Check the reference marks of the operating
gear pinion teeth (12) for corresponding reference marks on the operating gear teeth (1) and
engage the pinion in mesh with the teeth of the
113
Figure 4-24. Stadimeter housing assembly.
114
operating gear. Holding, the pinion in mesh,
place the operating gear (1) and the operating
gear pinion (12) together in the track sleeve (2).
The operating gear pinion shaft enters the
reamed hole of the bearing projection before
the tube section of the sliding track enters the
track sleeve. This method permits correct
alignment for the assembly of the stadimeter
transmission shaft coupling (14) so that the
taper pins (33) can be inserted correctly in
relation to the position of the upper part of
the stadimeter transmission shaft (22, Figure
4-27).
14. Place the sliding track lock rings (11)
in the counterbore of the track sleeve. The upper
ring has a slight counterbore. Screw this lock
ring on the threaded periphery of the sliding
track (3) and between the overlapping section
of the track sleeve (2) using a special wrench
until it comes up tight. Tap it lightly. Place the
lower lock ring (11) on in the same manner.
When this lock ring is tightened sufficiently
against the upper lock ring, the tapped recesses
of the lock ring and sliding track intersection
(3) should coincide, forming a tapped hole. Insert
the lockscrew (36) in this tapped hole in the
threaded intersection. If the tapped recesses do
not coincide, the upper ring requires further
tightening.
15. Place the detent pawl rest (8) in the 128 degrees
circumferential slot. A dowel pin fits into its
aligning hole in the sliding track (3) and will
fit only one way. Secure the detent pawl rest
to the periphery of the sliding track (3) with
two long and two short lockscrews (9 and, 10).
These lockscrews are inserted into countersunk
clearance holes in the detent pawl rest and
screwed into tapped holes in the sliding track.
The true 90 degrees rotation of this objective operating
mechanism assembly must be checked on the
V-blocks of an optical I-beam bench before
collimation.
16. Place the detent pawls (7) which have
reference marks to correspond to hinge projections of the track sleeve (2) at their respective
places. Insert the detent pawl shafts with similar
reference marks, through the reamed holes in
the track sleeve shoulder flange, and carry
them into the reamed holes in the hinge projections and the detent pawls. Secure each shaft
with a taper pin (32) inserted in the lower part
of each set of hinge projections.
17. Place the detent pawl spring (6) over both
detent pawls (7). Secure it with six lockscrews
(26), screwing three of these lockscrews into
tapped holes in each raised mount on opposite
sides of the circumferential slot.
18. Check the 90 degrees rotation before reassembly
of the lower (split) objective lens and mount
assembly halves (Figure 4-22) to the objective
operating mechanism assembly.
4J8. Description of the stadimeter housing assembly. The stadimeter housing assembly is
constructed as follows. (Figure 4-24 shows the
stadimeter housing assembly.) All bubble numbers in Sections 4J8, 9, and 10 refer to Figure
4-24 unless otherwise specified.
Ill. No.
Drawing Number
Num- ber Re- quired
Nomenclature
1
P-1159-11
1
Handwheel key
2
P-1159-12
1
Transmission gear pinion
3
P-1159-13
1
Handwheel shaft bevel gear
4
P-1159-14
1
Long transmission shaft
5
P-1159-17
1
Transmission shaft bevel gear
6
P-1159-18
1
Handwheel bracket
7
P-1163-10
8
Length of target scale mount retaining screws
8
P-1169-2
2
Scale ball bearing housings
9
P-1169-3
2
Scale housings
10
P-1169-4
2
Range scale actuating bevel gear pinions (front and rear)
11
P-1169-8
2
Range scale actuating bevel gears (front and rear)
12
P-1170-2
1
Handwheel
13
P-1170-13
2
Spring handle hinge screws
14
P-1171-1
4
Scale and transmission ball bearings
15
P-1171-16
2
Index line plates
16
P-1171-17
2
Length of target scale clamp screws
17
P-1171-18
4
Length of target scale knobs
18
P-1172-1
2
Length of target scale clamp screw retaining collars
19
P-1172-2
2
Length of target scale clamp screw retaining collar rivets
20
P-1172-3
5
Transmission ball bearings
21
P-1172-4
2
Transmission ball bearing housings
22
P-1172-5
2
stadimeter housing dowel pins
23
P-1172-6
1
Handwheel shaft
115
Ill. No.
Drawing Number
Num- ber Re- quired
Nomenclature
24
P-1172-7
1
Spring handle stud
25
P-1172-8
1
Spring handle
26
P-1172-9
1
Spring handle plunger
27
P-1172-10
1
Spring handle plunger nut
28
P-1172-11
1
Spring retaining nut
29
P-1172-12
1
Plunger spring
30
P-1172-13
4
Stadimeter housing bolts
31
P-1172-15
1
Transmission shaft pinion bevel gear key
32
P-1172-17
2
Front and rear range scale actuating bevel gear ball bearings
33
P-1179-37
4
Star wheel lock plunger housing lockscrews
34
P-1179-46
6
Stadimeter housing cover plate lockscrews
35
P-1179-50
1
Handwheel lockscrew
36
P-1179-60
1
Transmission shaft pinion bevel gear lockscrew
37
P-1179-68
4
Handwheel bracket lockscrews
38
P-1179-69
4
Index line plate lockscrews
39
P-1179-70
8
Height scale mount lockscrews
40
P-1179-71
8
Range scale mount lockscrews
41
P-1179-72
8
Ball bearing housing lockscrews
42
P-1179-73
16
Scale housing lockscrews
43
P-1179-74
32
Various dial lockscrews
44
P-1179-197
4
Transmission gear pinion, handwheel shaft bevel gear, star wheel, and star wheel key taper pins
45
P-1179-198
2
Front and rear range scale actuating gear pinion taper pins
a. Stadimeter housing. The stadimeter
housing (67) is made of cast phosphor bronze.
It consists of a cored rectangular box section
called the center section, with front and rear
projections forming a part of the casting. These
are called the front and rear scale housings.
The center section carries the transmission
mechanism to operate the scale dial mechanisms
of the front and rear housings simultaneously
with the various interconnecting shafts and
couplings to operate the objective operating
mechanism assembly (Figure 4-23) and the lower
(split) objective lens and mount assembly (Figure 4-22) as a single unit called the stadimeter.
The walls of the center section are of rectangular design and have their outer four
corners beveled. The inner four corners of this
section are filleted inward sufficiently to accommodate clearance holes for the four stadimeter
housing bolts (30). These bolts, inserted from
the four spot faced corners of the base, secure
the stadimeter housing to the eyepiece box (11,
Figure 4-29). There are two dowel pins (22)
inserted in the upper wall face which are located
116
diagonally to insure a rapid reference for reassembly of this housing. These dowel pins are
a force fit into the reamed holes in the eyepiece
box base (11, Figure 4-29).
An inward projecting semi-circular lug of
sufficient thickness provides the necessary support for the transmission shaft pinion (65) and
its perpendicular, supporting parts, for interconnection with the stadimeter transmission
shaft (22, Figure 4-27), of the first inner tube
section assembly. Directly below this semicircular lug, in the base of the center section, a
semi-circular raised section accommodates the
lower supporting parts of the transmission shaft
pinion (65).
A raised section shaped like the letter G,
0.937 inch in height, is supported by a narrow
rib from the front filleted corner, extending
forward from the inner rear wall of the center
section. This part, having ample wall thickness,
accommodates the three way interconnection
of the transmission, by means of four mounted
ball bearings (14 and 20).
The lower part of the stadimeter housing is
cored inward to the center part, with supporting
ribs to the front and rear scale housing section
walls. The center section and lower face are
bored, faced, and threaded. The lower fate of
this section contacts the bumper located in
the well of the submarine. At various times it
is necessary, because of the construction of a
submarine, to insert a filler piece in the threaded
section in the lower center part of the stadimeter
housing base.
The front, rear, and right side walls of the
center section have openings to accommodate
ball bearings for the operation of the transmission and the front and rear scale housing
mechanisms. The lower wall of each scale housing
section has a tapped hole to receive alemite
fittings (82) for the introduction of grease.
b. Handwheel. The handwheel (12) is made
of cast phosphor bronze. It is of sufficient.
diameter to permit easy operation of the
stadimeter, with the periphery scalloped. The
inner scalloped circumference is cored and
allows only sufficient wall thickness for six of
the scallops. Three of the scallops of one section
are solid for the assembly of a spring handle.
This assembly is swung vertically or horizontally
at will by the observer, and is locked in either
position by means of a plunger under spring
pressure, extending into clearance holes in the
inner wall of the remaining wall of the machined
scallop. This spring handle when swung horizontally, provides the observer with a means
for rapid turning of the handwheel if desired.
One scallop opposite the spring handle assembly
is solid to balance the handwheel for the increased weight.
The inner wall of the handwheel is scored with
four flat spokes which project inward to the hub
section and have a square appearance. The hub
section is filleted toward its diameter, and has a
reamed hole and a keyseat to receive the outer
part of the handwheel shaft (23) with an inserted
key (1). The handwheel is secured to the handwheel shaft with a lockscrew (35). This lockscrew
is inserted into a tapped hole in the handwheel
hub section and extends into a spotted recess,
thus preventing the handwheel from coming
off the shaft.
The center of the three solid scallops is
machined out to receive the hinge section of
the spring handle stud (24) and its cylindrical
shoulder. This milled out section is provided
with sufficient clearance to allow the spring
handle stud (24) to rotate 90 degrees. It is secured
in the handwheel by two spring handle hinge
screws (13). These screws fit into countersunk
tapped holes located on opposite sides of the
machined scallop in the periphery, with their
centerline offset from the scalloped periphery
wall 1/16 inch. Two clearance holes are provided
in this machined scallop, located 90 degrees apart,
for the spring handle plunger (26). This allows
the spring handle assembly to be locked in
either the extended or folded position.
c. Spring handle stud, plunger, plunger
spring, spring retaining nut, and spring
handle. 1. Spring handle stud. The spring
handle stud (24) is made of rolled bronze and
is nickel plated. The hinge section is square
with the corners rounded off to provide 90 degrees
rotation in the milled section of the handwheel
(12). Two opposite reamed holes in this section
serve as pivot bearings for the spring handle
hinge screws (13) which extend from countersunk tapped holes in the scalloped periphery
117
into reamed holes in each wall of the hinge
section. The undercut section of the screws
fits into the reamed holes. The outer surface
of the main body carries the spring handle (25)
up to "the narrow shoulder. The diameter of the
shoulder conforms to the diameter of the contacting part of the spring handle.
The inner surfaces are provided with two
reamed holes, the smaller of which receives the
shorter stem of the spring handle plunger (26),
and the larger receives the narrow shoulder section of the spring handle plunger and the plunger
spring (29). The outer part of the large reamed
hole is threaded 1/8 inch deep to receive the
spring retaining nut (28) to compress the
plunger spring.
2. Spring handle plunger. The spring
handle plunger (26) is made of monel metal
and is 2 5/8 inches long. The shorter stem which
is 1 5/16 inch long is rounded off at the end; this
section extends from the reamed hole in the
spring handle stud (24) under tension of the
plunger spring (29) to snap into either of the 90 degrees
clearance holes in the handwheel (12) to retain
the assembled spring handle in the extended or
folded position.
The narrow shoulder section of the handle is
a sliding fit in the large reamed hole in the spring
handle stud (24) with the plunger spring (29)
fitting over the long stem section against the
narrow shoulder section. The plunger spring
under tension carries this shoulder to the bottom
of the large reamed hole. The outer part of the
long stem section is undercut and threaded, and
carries the small reamed and countersunk outer
part of the spring handle, securing it with a
plunger nut (27).
3. Plunger spring. The plunger spring (29)
is made of No. 16 gage music wire and is 3/4-inch
free length. The spring fits over the long section
of the spring handle plunger (26) and is placed
under a nominal tension by the spring retaining
nut (28) to retain the narrow shoulder section of
the plunger against the bottom shoulder of
the large reamed hole. Sufficient compression
of the spring allows the short section of the
plunger to be released from the locking clearance
holes in the handwheel (12).
4. Spring retaining nut. The spring retaining nut (28) is made of rolled bronze and is
1/8-inch thick. It is cylindrical and has a threaded
periphery to screw into the threaded outer part
of the spring handle stud (24). It has a reamed
hole in its axis to allow the long section of the
plunger a sliding fit. Two shallow drilled holes
are provided in the side face for a special wrench.
The retaining nut compresses the plunger spring
(29) normally and is secured tightly in the
bottom of the threaded outer part of the spring
handle stud.
5. Spring handle. The spring handle (25)
is made of rolled bronze and is nickel plated.
It is of sufficient length with the outer corners
rounded off. The outer surface has a 1/2-inch
knurled band to offer a firm grip to the observer.
The inner surface has a reamed hole which is
countersunk in the outer part. The reamed hole
is a sliding fit over the long section of the spring
handle plunger (26). It is counterbored a sliding
fit over the main body of the spring handle stud
(24), and is secured with nominal clearance by
a plunger nut (27). The plunger nut is a sliding
fit in the outer countersunk reamed hole in the
outer part, and is slotted in its side face for a
special wrench. The upward movement of
the spring handle against spring tension causes
its countersunk face to contact the plunger nut
(27) which is attached to the spring handle
plunger (26) thus carrying the plunger outward,
compressing the plunger spring (29), and removing the short stem section of the plunger from
its locked position in the handwheel (12). Once
the plunger is released from its locked position,
it automatically snaps into the opposite locked
position upon rotation and when lined up for
proper engagement.
d. Handwheel bracket and shaft. 1.
Handwheel bracket. The handwheel bracket
(6) is made of phosphor bronze and is 5/8 inch
in length. The large diameter of the shoulder
flange is of nominal thickness and is filleted
to the hub section. It is secured to the right side
wall of the stadimeter housing center section
with four lockscrews (37). These lockscrews
are inserted in countersunk clearance holes and
screwed into tapped holes in the center section
wall. The inner surface has a reamed hole for
the handwheel shaft (23) and a shallow counterface to allow clearance over the ball bearing
(20) extending from the alignment counterface
118
of the center section wall. The small raised
alignment shoulder of the bracket is a push fit
into the alignment counterface. The bracket
serves as a support for the weight of the handwheel (12) and the protruding part of the
handwheel shaft (23). It also prevents foreign
matter from entering the ball bearing (20).
2. Handwheel shaft. The handwheel shaft
(23) is made of corrosion-resisting steel rod and
is 7 1/8 inches in length. The outer part of the
shaft is provided with a keyway for the insertion
of a handwheel key (1), and receives the handwheel (12) which is secured with a lockscrew
(35) that protrudes from the tapped hole in
the handwheel hub and extends into a spotted
recess in the shaft. This shaft is mounted in
three ball bearings (20), with the first ball
bearing in the right side wall of the center section.
The shaft protrudes into the center section from
the right side wall of the stadimeter housing.
In the center section, a nominal distance from
the inner right wall, a star wheel (59) is secured
to the handwheel shaft (23) with a taper pin (44)
inserted through the hub section. This section
faces the inner wall. A star wheel lock plunger
housing (64) is provided between the star wheel
(59) and the next ball bearing (20).
The second ball bearing (20) is a push fit
over the handwheel shaft (23) and is mounted
in a transmission ball bearing housing (21).
The housing is secured to the lower part of the
raised G-wall in the center section with two
lockscrews (41). These lockscrews are inserted
into countersunk clearance holes in the housing
and screwed into tapped holes in the raised
G-wall section.
Directly inward of this mounted ball bearing
(20), a handwheel shaft bevel gear (3) is attached
to the handwheel shaft with a taper pin (44)
inserted through the hub section. This section
faces the second ball bearing (20).
The shaft is mounted a push fit in the third
ball bearing (20) mounted in a housing (21)
which is secured to the upper part of the raised
G-wall section in the center section. The housing
is secured to this wall face with two lockscrews
(41). These lockscrews are inserted into countersunk clearance holes in the housing and screwed
into tapped holes in this raised G-wall section
face.
Directly outward of this ball bearing on the
opposite end of the handwheel shaft, a woodruff
keyway is cut in this stub section, to accommodate a No. 10 woodruff key (31). This woodruff key is inserted in the stub section to receive
the transmission shaft bevel gear (5). This
bevel gear is secured to the handwheel shaft
(23) by means of a lockscrew (36). The lockscrew is inserted into a tapped hole in the bevel
gear hub section and extends into a spotted
recess in the shaft.
The handwheel shaft mounted in three ball
bearings, operates the front and rear scale
housing mechanisms by means of the handwheel
shaft bevel gear (3) which engages with the
front and rear transmission gear pinions (2 and
54). It also operates the objective operating
mechanism assembly by means of the transmission shaft bevel gear (5) which engages with
the transmission gear pinion (65). Both of the
scale housing mechanisms and the transmission
shaft pinion are rotated simultaneously as the
handwheel (12) operates the handwheel shaft
(23) for clockwise or counterclockwise rotation.
e. Transmission shaft pinion. The transmission shaft pinion (65) is made of corrosion resisting steel and is 2.933 inches in length.
The pinion is cut as an integral part of the shaft.
It has 26 bevel teeth of 32 diametral pitch
which mesh at right angles with 54 bevel teeth
of the transmission shaft bevel gear (5). This
transmission shaft pinion is mounted vertically
in the center section at right angles to the handwheel shaft (23) and parallel to its centerline.
A part of the long section of the pinion shaft
is undercut below the pinion to allow clearance
for cutting of the bevel teeth. The lower part
of the pinion shaft is a push fit in a ball bearing
(20) which in turn is a push fit in the raised
semicircular section in the lower wall of the
center section. The upper part of the stub shaft
section above the pinion is mounted a push fit
in a ball bearing (20), which in turn is mounted
a push fit into the semicircular lug section of
the center section projecting inward. The face
of this semicircular lug section is provided with
a ball bearing retainer (70) secured with four
lockscrews (57).
The upper part of the stub shaft section is
cut away a depth of 3/8 inch forming a male tang
119
section far the assembly of a female tang
coupling (68) secured snugly against the race
of the ball bearing with a taper pin (58). This
stub shaft section projects upward with the
assembled female tang coupling from the upper
face of the stadimeter housing center section.
The lower part of the long shaft section of the
pinion shaft is provided with a thrust collar
(66). This thrust collar is secured to this part
of the shaft in contact with the lower ball bearing
race with a taper pin (58). The thrust collar is
adjusted before securing, so that the pinion
teeth are engaged with the transmission shaft
pinion bevel gear (5) at operating depth,
with no lost motion in the pinion or its mating
bevel gear.
f. Star wheel. The star wheel (59) is made
of corrosion-resisting steel 1/2 inch wide. It is
provided with a large shoulder section in which
22 teeth of non-standard design are cut for the
engagement of a star wheel key (60). The inner
surface has a reamed hole which is a sliding fit
on the handwheel shaft (23). It is secured to this
shaft with a taper pin (44) inserted through the
hub section of the star wheel, with the hub
section facing the inner right side wall of the
stadimeter housing center section. The face
of the star wheel is fitted close to the star wheel
lock plunger housing (64), and receives the star
wheel key (60) which is secured in a star wheel
key holder (61) with a taper pin (44) under
tension of a star wheel lock plunger spring (63).
g. Handwheel and transmission shaft
bevel gears. 1. Handwheel shaft bevel gear.
The handwheel shaft bevel gear (3) is made
of phosphor bronze with a reamed hole in its
center axis, a sliding fit on the handwheel
shaft (23). The large diameter is provided with
40 bevel teeth of 32 diametral pitch, which
mesh at right angles with a transmission gear
pinion (2) of 20 beveled teeth on the front
side of the handwheel shaft (23). It also meshes
with a transmission gear pinion (54) on the
opposite (or rear) side for actuation of the front
and rear scale housing mechanisms. This bevel
gear is provided with a hub section into which
the taper pin (44) is secured, with this section
facing away from its mating pinions.
2. Transmission shaft bevel gear. The
transmission shaft bevel gear (5) is made
of phosphor bronze with a reamed hole in its
center axis, and is provided with a keyseat.
It is a push fit over the inserted woodruff
key (31) on the stub section of the handwheel
shaft (23). The large diameter is provided with
54 bevel teeth of 32 diametral pitch, which
mesh with the 20 bevel teeth of the transmission
shaft pinion (65) located vertically at right
angles. It is provided with a hub section which
faces the shoulder of the handwheel shaft (23)
and is secured with a lockscrew (36). This
lockscrew is inserted in a tapped hole in the hub
section of this bevel gear and extends into a
spotted recess in the handwheel shaft (23).
h. Transmission ball bearing housings,
ball bearing retainer, and ball bearings.
1. Transmission ball bearing housings. The
transmission ball bearing housings (21) are
made of cast phosphor bronze and are 1 5/8 inches
long. They are of proportional thickness to
provide a rigid foundation for the ball bearings
(20) and actuation of the transmission. Each
is bored to accommodate the handwheel shaft
(23) and to permit the rapid removal of each
ball bearing. A counterbore 1/4 inch deep is
provided in each housing for the assembly of
two ball bearings (20), a press fit in each of the
counterbores. The height of the housings is
proportional to the establishment of a parallel
transmission centerline, with each upper part
having a radius to accommodate sufficient wall
thickness. Each housing is provided with two
dowel pins, for rapid alignment upon reassembly.
These dowel pins fit into shallow holes in the
face of the raised G-wall section face. Each
housing is secured to this raised G-wall section
face with two lockscrews (41) located in tapped
holes in the wall. These lockscrews are inserted
in countersunk clearance holes of appropriate
center distance in the housing and screwed into
tapped holes in the raised G-wall section. The
bored holes in the assembled housings face each
other at assembly.
2. Ball bearing retainer. The ball bearing
retainer (70) is made of 1/16-inch thick brass.
It is cylindrical with a clearance hole in the
center axis. It is secured in contact with the
ball bearing (20) to the face of the semi-circular
lug section with four lockscrews (57). These
lockscrews are inserted in four equally spaced
countersunk clearance holes in the retainer and
120
screwed into tapped holes in the semi-circular
lug section. This retainer prevents the transmission shaft pinion (65) from being displaced
axially. A recess is provided in the periphery,
where it overlaps the clearance holes for the
stadimeter housing bolt (30).
3. Ball bearings. The ball bearings (20)
for the transmission shaft pinion (65) are
mounted a push fit in the bored holes of the
semicircular lug section and the semicircular
raised section, a part of the lower base wall of
the center section. Each ball bearing is a push
fit over the lower part of the long shaft section
of the transmission shaft pinion (65) and also
over the stub section of the upper part.
i. Female tang coupling. The female tang
coupling (68) is made of phosphor bronze- and
is 0.812 inch in length. The outer surface is
cylindrical with a broached hole of a partially
circular design in the center axis. This broached
hole fits over the transmission shaft pinion
(65) male tang to contact the ball bearing (20)
and is secured with a taper pin (58). The
remaining part of the coupling receives the
stadimeter transmission shaft male tang section
(22, Figure 4-27) for actuation, and is a sliding
fit in this part. The coupling projects above
the face of the stadimeter housing center
section and is connected to the stadimeter
transmission shaft tang section (22, Figure 4-27)
upon assembly of the stadimeter housing
assembly to the base of the eyepiece box (11,
Figure 4-29).
j. Star wheel lock plunger housing,
plunger, key holder, and key. 1. Star
wheel lock plunger housing. The star
wheel lock plunger housing (64) is made of
cast phosphor bronze and is 2 3/4 inches in length.
The outer surface is cylindrical, with a rectangular flange in the lower part. The inner
surface has a reamed hole and two counterbored sections; the small counterbored section
and reamed hole receive the lock plunger (62)
which is a loose fit. The large counterbored
section receives the keyholder (61) which is
also a loose fit. Both sides of the housing perpendicular to the narrow rectangular part of the
flange are slotted to allow the protruding
parts of the star wheel key (60) vertical guidance
and also to fit over the handwheel shaft (23). The
rectangular base is secured to the machined
center section boss over the handwheel shaft
(23) with four lockscrews (33). These lockscrews are inserted into counterfaced clearance
holes in the housing flanges and screwed into
tapped holes in the center section boss. The
periphery of the housing on the slotted sides
is filed off for clearance between the ball bearing
housing (21) and the star wheel (59).
2. Star wheel lock plunger. The star wheel
lock plunger (62) is made of phosphor bronze
and is 1 1/2 inches in length. It is cylindrical, with
a small undercut section a loose fit in the
reamed hole in the plunger housing (64), while
the large periphery is a loose fit in the small
counterbored section in the same housing.
The larger diameter is slotted to a distance of
3/4 inch, to allow its free vertical movement
over the handwheel shaft in the housing. The
lower part rests in the counterfaced upper
part of the keyholder (61). This plunger, in
contact with the keyholder (61) under tension
by the plunger spring, is carried to its upper
extreme position, and the star wheel key (60)
is engaged with the star wheel (59) locking
the handwheel shaft (23) and the transmission.
3. Star wheel key holder. The star wheel
key holder (61) is made of phosphor bronze
and is 0.781 inch in length. Its outer surface is
cylindrical, a loose fit in the large counterbore
of the lock plunger housing (64). The upper
part is counterfaced a shallow depth to provide
a seat for the lower part of the lock plunger (62),
while the lower part is counterbored 3/16 inch
to provide clearance and guidance for the
plunger spring (63). A reamed hole is provided
perpendicular to its axis a short distance from
the upper part to receive the star wheel key (60)
which is secured with a taper pin (44) in its
center axis. The rear side of the key extends
beyond the periphery 1/32 inch to provide vertical guidance of the assembled key holder and
key in the vertical slots of the plunger housing
(64).
4. Star wheel key. The star wheel key (60)
is made of corrosion-resisting steel material
and is 1 1/8 inches in length. The key section is
0.281 inch in length and is a true profile of
the star wheel non-standard teeth. The supporting body of the key is a push fit in the
121
reamed hole in the key holder (61) and is
secured with a taper pin (44).
k. Automatic stop. The automatic stop
prevents rotation of the handwheel (12) when
the stadimeter housing is not in place, and insures correct reassembly. The locking device
consists of a star wheel (59) mounted on the
handwheel shaft (23) which is secured with a
taper pin (44), and with the following parts
enclosed in a star wheel lock plunger housing
(64): star wheel lock plunger (62), star wheel
key (60), its holder (61), and a plunger spring
(63).
The star wheel key (60) in the locked position
is engaged in the teeth of the star wheel (59)
by means of the tension placed against the key
holder (61) by the plunger spring (63). In this
position the lock plunger (62) is carried to its
upward position by the key holder (61). When
the stadimeter housing assembly is attached
to the base of the eyepiece box (11, Figure 4-29)
and secured with four stadimeter housing bolts
(30), the screw head (6, Figure 4-29) projecting
from the base of the eyepiece box (11, Figure
4-29) contacts the lock plunger (62) and pushes
it downward, disengaging the star wheel key
(60) from the star wheel (59) compressing the
plunger spring (63). This automatic device locks
the handwheel (12) and the transmission that the
broached tang hole of the female tang coupling
(68) couples with the stadimeter transmission
shaft male tang section (22, Figure 4-27) for
proper relation to the proper position of the
lower (split) objective lens and the stadimeter
dials.
l. Long transmission shaft and gear
pinion. 1. Long transmission shaft. The
long transmission shaft (4) is made of corrosion-resisting steel and is 3 3/8 inches in length. It is
mounted in two ball bearings (14). One is
located in the center section front wall, while
the other is located in the scale ball bearing
housing (8) located on the face of the raised
G-wall sections and perpendicular to the ball
bearing housings (21). On the inner end of
this shaft a transmission gear pinion (2) is
secured with a taper pin (44), while the opposite
end extends into the front scale housing section
to receive the range scale actuating bevel gear
pinion (10) which is secured with a taper pin
(45). This shaft operates the front scale housing
mechanism by means of the attached pinions.
2. Transmission gear pinion. The transmission gear pinion (2) is made of phosphor
bronze with a reamed hole in its center axis
a push fit on the inner end of the long transmission shaft (4). The large diameter is provided
with 20 bevel teeth of 32 diametral pitch, to
mesh at right angles with the 54 bevel teeth of
the handwheel shaft bevel gear (3). It is provided
with a hub section which faces toward the
mounted ball bearing (14) in the scale ball
bearing housing (8) and is secured with a taper
pin (44). This gear pinion transmits motion
to the long transmission shaft (4) for actuation
of the front scale housing mechanisms.
m. Short transmission shaft and gear
pinion. 1. Short transmission shaft. The
short transmission shaft (53) is made of corrosion-resisting steel and is 1 1/2 inches in length.
It is mounted in two ball bearings (14). One
is located in the center section rear wall, while
the other is located in the scale ball bearing
housing (8) located on the face of the raised
G-wall section and perpendicular to the transmission ball bearing housings (21). The inner
part of this shaft is provided with a keyway
for the insertion of a key (56). It is provided
with a tapped hole in the center axis of this
end for a lockscrew (55).
On the inner end of this shaft a transmission
gear pinion (54) is secured over the inserted key
(56) by means of a lockscrew (55). The lockscrew
screws into the tapped hole in the center axis
of the shaft. The opposite end of this shaft
extends into the rear scale housing section to
receive the range scale actuating gear pinion
(10) secured with a taper pin (45). This shaft
operates the rear scale mechanism by means of
attached pinions.
2. Transmission gear pinion. The transmission gear pinion (54) is made of phosphor
bronze with a reamed hole in its center axis,
and is provided with a keyseat. This pinion is a
push fit over the inserted key (56) located in
the inner end of the short transmission shaft
(53) and is secured against the race of the ball
bearing (14) snugly by means of the lockscrew
(55). This lockscrew screws into the tapped hole
in the inner end of the shaft. The large diameter
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of this pinion is provided with 20 bevel teeth
of 32 diametral pitch which mesh at right angles
with the 54 bevel teeth of the handwheel shaft
bevel gear (3) for actuation of the rear scale
housing mechanism.
n. Scale ball bearing housings and ball
bearings. 1. Scale ball bearing housings.
The scale ball bearing housings (8) are similar
to the two transmission ball bearing housings
(21) except for the diameter of the clearance
holes, the counterbored sections, and the radius
of the upper wall. They are used to mount
each ball bearing (14) a press fit into each
counterbored, section. Both of these housings
are located on the raised G-wall section and
perpendicular to the two transmission ball
bearing housings. They are secured with two
lockscrews (41) each, which are inserted into
countersunk clearance holes in the housing
and screwed into tapped holes in the raised
G-wall section. Both housings provide a rigid
support for the transmission gear pinions (2
and 54) for their actuation with the handwheel
shaft bevel gear (3).
2. Ball bearings. The four ball bearings
(14) provide smooth actuation to the long and
short transmission shafts (4 and 53) in the center
section mounted in scale ball bearing housings
(8) for the inner parts of these shafts. Two ball
bearings are mounted, a press fit into the counterbored sections in the front and rear walls of the
scale housing sections. They are inserted from
the scale housing side with a clearance hole
of sufficient size for their removal. These two
ball bearings support the outer part of the long
and short transmission shafts (4 and 53) for the
free actuation of each scale housing mechanism.
o. Range scale actuating bevel gear pinions. The two range scale actuating bevel gear
pinions (10) are made of phosphor bronze with a
reamed hole in each center axis. The large
diameter of each is provided with 20 bevel
teeth of 32 diametral pitch, with a pitch cone
line angle of 17 degrees 4', which mesh with 80 bevel
teeth of a range scale actuating bevel gear (11)
having a pitch cone line angle of 72 degrees 56'. Each
is provided with a hub section which faces
toward the assembled ball bearing (14) located
in the wall of each scale housing section. The
gear pinions are a push fit on each long and short
transmission shaft (4 and 53) and are secured
with a taper pin (45). Both pinions operate the
range scale actuating bevel gears (11) of the
front and rear scale housing mechanisms.
p. Scale housings. The scale housings (9)
are made of cast phosphor bronze and are
1 13/16 inches in length. Both housings are
provided for the front and rear scale housing
sections of the stadimeter housing (67). The
outer and inner walls are beveled at 45 degrees forming
a conical shape, and have equal wall thickness.
This conical wall is undercut on the outer surface
to form a shoulder flange, and is a sliding fit in
the bored and counterbored section of the scale
housing section. It is secured with eight lockscrews (42) which are inserted in countersunk
clearance holes in the scale housing shoulder
flange and screwed into tapped holes in the
counterbored face of the scale housing section.
The lower part of the conical wall is flat with
a diameter of 2 9/16 inches, with the conical
wall and lower part conforming to the inner cored
conical and flat walls of the scale housing section.
A clearance hole of sufficient size is provided
in the conical wall to accommodate the long
transmission shaft (4) and the range scale
actuating gear pinion (10) of the front scale
housing section. The same provision allows
clearance for the protrusion of the short transmission shaft (53) and the range scale actuating
gear pinion (10) of the rear scale housing section.
The inner lower wall face is provided with two
raised shoulders of varying diameter, wall thickness, and depth. The space between the two
shoulders allows clearance for the small chamfered shoulder of the range scale actuating bevel
gear (11) and serves as a grease cell. The large
shoulder is a contact face with the inner side
face of the range scale actuating bevel gear (11),
thereby providing the height or thrust adjustment to this bevel gear. The counterbored section
of the small shoulder receives the lower face
of the height scale mount (51), and is secured
with four equally spaced lockscrews (39). These
screws are inserted in countersunk clearance
holes in the height scale mount (51) and screwed
into tapped holes in this counterbored face.
A tapped hole in the center axis of this counterbored face is provided for the insertion of a
jacking screw for the removal of the scale
housing.
123
The inner surface of the shoulder flange section
has two counterbored sections to carry the
length of target scale mount (47). The smaller
of the two counterbored sections has four
equally spaced tapped holes, countersunk in
the periphery to receive four length of target
scale mount retaining screws (7), thus retaining,
the length of target scale mount (47). These
screws project into an undercut groove in the
mount periphery, to retain it in the scale housing
and also to allow its free actuation.
The shoulder flange of this scale housing is
provided with a clamp screw (16) which screws
into the countersunk tapped hole in the shoulder
flange. It is secured from backing out of the
tapped hole with a retaining collar (18) which
in turn is secured with a rivet (19). The clamp
screw shoulder (16), when in contact with the
assembled length of target scale dial (48),
clamps it with the mount at any desired length
of target suitable for obtaining the course angle
of an enemy ship by the observer. The counterbored shoulder of each scale housing section is
slotted to provide clearance for the clamp screw
assembly located in the right side of the scale
housing outer face, at right angles to the conical
wall clearance hole.
An index line plate (15) is attached to the
scale housing face located opposite the conical
wall clearance hole and is secured with two
lockscrews (38).
q. Length of target scale mounts. The
two length of target scale mounts (47) are made
of cast phosphor bronze, and are provided for
the stadimeter housing front and rear scale
housing sections. The mounts are cylindrical,
of single step design, with small and large
diameter shoulders which are a sliding fit in
the small and large counterbores in the scale
housings (9). The small periphery shoulder is
provided with an undercut groove to accommodate the protrusion of four retaining screws
(7). These screws extend inward from four
equally spaced countersunk tapped holes in the
scale housings (9) for their protrusion in this
groove, to retain the mount in its seat, and to
offer free actuation to the mount.
The inner surface is bored for operational
clearance over the range scale mount (49),
and is provided with a chamfer to break off
the inside shoulder. The mount face carries a
length of target scale dial (48) secured with six.
lockscrews (43) and two lengths of target scale
knobs (17). The lockscrews are equally spaced
and are inserted in countersunk clearance holes
in the scale dial and screwed into tapped holes
in the mount. The knobs are located on opposite
sides and are secured in tapped holes in the
mount. They serve to allow the observer to
rotate and set the assembled mount to the
reference line of the index line plate (15) to
any desired length of an enemy ship.
r. Range scale actuating bevel gears,
ball bearings, and mounts. 1. Range scale
actuating bevel gears. The two range scale
actuating bevel gears (11) are made of phosphor
bronze and are used for the front and rear scale
housing mechanisms. The large diameter has
80 bevel teeth of 32 diametral pitch, with a
pitch cone line angle of 72 degrees 56' which mesh with a
range scale actuating gear pinion (10) of 20 bevel
teeth having a pitch cone angle of 17 degrees 4'.
The lower face has a chamfered shoulder
which forms a sufficient wall for the counterbored
section to receive the ball bearing (32), a press
fit in this part against the inner shoulder seat.
The shoulder is bored for the protrusion of the
lower part of the height scale mount (51).
The large lower face revolves in contact with
the large raised shoulder of the scale housing
(9) to maintain its axial height adjustment.
The upper face has a shallow counterfaced
recess serving as an alignment seat for the range
scale mount (49) which is secured with four
lockscrews (40). The lockscrews are inserted
into clearance holes located in the small counterbored face of the range scale mount and screwed
into tapped holes in this bevel gear. The bevel
gear carries the range scale mount (49) and its
attached range scale dial (50) for all ranges of
its engraved graduations.
2. Range scale actuating bevel gear ball
bearings. The two range scale actuating
bevel gear ball bearings (32) are of a torque
tube type. Both ball bearings are used for the
front and rear scale housing mechanisms. They
are mounted a press fit into the counterbored
sections in each range scale actuating bevel gear
(11) and the other races rest against the counterbored shoulder seat The height scale mount
124
(51) lower part is a push fit in its center race.
These ball bearings offer smooth actuation to
the range scale actuating bevel gears.
3. Range scale mounts. The two range
scale mounts (49) are made of cast phosphor
bronze and are used for the front and rear scale
housing mechanisms. The mounts are cylindrical
with a large diameter shoulder flange section of
nominal thickness. The outer surface of the
shoulder flange is chamfered at 30 degrees, while
the remaining outer wall is beveled conical. The
lower part of the conical wall is provided with a
small shoulder, which serves as an alignment
support section and is a push fit into the alignment recess seat in the range scale actuating
bevel gear (11).
The inner surface is a three step design; it
has a bore of sufficient size for operational
clearance of the ball bearing center race (32),
and the protrusion of the height scale mount
lower part (51). It has small and large counterbored sections. The smaller counterbored section
lightens the mount with sufficient clearance to
carry the four lockscrews (40). These lockscrews
are inserted into four equally spaced clearance
holes in the lower shoulder and screwed into
tapped holes in the range scale actuating bevel
gear (11).
The large counterbored section provides
clearance for the large periphery of the height
scale mount (51) and also lightens it. The outer
face of the mount is provided with two dowel
pins (46), a drive fit into opposite drilled holes,
which are not both located in the centerline for
reassembly alignment of the range scale dial
(50). This outer face carries the range scale dial
secured with six lockscrews (43). These lockscrews are inserted into equally spaced countersunk clearance holes in the range scale dial and
screwed into tapped holes in the range scale
mount flange.
s. Height scale mount. The two height scale
mounts (51) are made of phosphor bronze and
are used for the front and rear scale housing
mechanisms. The periphery of the mount is a
solid shoulder of nominal thickness and serves to
carry the height scale dial (52). It is provided
with two small shoulders, the smaller a push fit
in the ball bearing (32) with the larger shoulder
seat resting against the face of the ball bearing
center race. The mount is secured to the ball
bearing race with four lockscrews (39). The
mount does not actually touch the small counterbored face of the scale housing (9), but is a
sliding fit in the small counterbored section in
the scale housing raised shoulder.
Four equally spaced countersunk clearance
holes extend the entire length of this mount
for the lockscrews (39). These lockscrews secure
the mount to the ball bearing race by their
protrusion into tapped holes in the scale housing
lower wall. The outer face of the mount is
provided with two dowel pins (46), a drive fit
into opposite drilled holes, which are not both
located in the centerline for reassembly alignment of the height scale dial (52). This outer
face carries the height scale dial (52) secured
with four lockscrews (43).
In the center axis of both mounts tapped
holes are provided for pointer shoulder screws
(75) to retain pointer assemblies. These mounts
are stationary in the scale housings (9).
t. Length of target scale dials, index line
plates, range and height scale dials. 1.
Length of target scale dials. The two lengths
of target scale dials (48) are made of 1/16-inch
bakelite and are cylindrical. These dials are
provided for the front and rear scale housing
mechanisms. The inner and outer surfaces
conform with their mounts, to which they are
secured with six lockscrews (43) each. These
lockscrews are inserted into equally spaced
countersunk clearance holes and screwed into
tapped holes in the length of target scale mounts
(47).
Two clearance holes directly opposite are
provided for each set of length of target scale
knobs (17) which extend into tapped holes in
the mount. It is graduated as before mentioned.
2. Index line plates. The two index line
plates (15) are made of brass and are 5/8 inch
in length. They are used for the front and rear
scale housings (9). The width is proportional
to the scale housing outer face, with the inner
and outer radius conforming to the contour
of its inner circumference and periphery. The
inner radius is chamfered at 45 degrees and is provided
with an index line 0.025 inch deep. The plates
are secured with two lockscrews (38) to the
125
scale housing outer faces with the index line
located in the centerline opposite the conical
wall clearance hole.
3. Range scale dials. The two range scale
dials (50) are made of 1/16-inch bakelite and
are cylindrical. These dials are provided for the
front and rear scale housing mechanism. The
inner and outer surfaces conform to their mounts,
to which they are secured with six lockscrews
(43) each. These lockscrews are inserted into
equally spaced countersunk clearance holes in
the scale dials and screwed into tapped holes
in each range scale mount (49).
Two opposite clearance holes in each dial
not directly in the centerline fit over inserted
dowel pins (46) in each mount for proper
reassembly. Both dials are graduated as before
mentioned.
4. Height scale dials. The two height scale
dials (52) are made of 1/16-inch bakelite and are
cylindrical. These dials are provided for the
front and rear scale housing mechanisms.
The periphery of the dials conforms to the
periphery of their mounts. The dials have
opposite clearance holes not directly in the
centerline to fit over the inserted dowel pins
(46) of their mounts. Each is secured to its
respective height scale mount face (51) with
four lockscrews (43). These lockscrews are
inserted into countersunk clearance holes in
each dial and screwed into tapped-holes in each
mount.
The clearance hole in each dial center axis
receives the lower pointer collar (76) of the
pointer assemblies. The dials are graduated as
before mentioned.
u. Factors governing the graduations.
The factors governing the graduation of the
height, range, and length of target scale dials
are: 1) focal length of the whole optical system
(that is, the magnification or power), 2) angular
displacement of the lower (split) objective lens,
and 3) equivalent focal length of the upper
eyepiece lens.
v. Pointer assemblies. The two pointer
assemblies are provided for the front and
rear scales. They consist of two pointers each
located on the center of the height scale dials.
The lower pointer is used for the height scale
dials (52), while the upper is used for the course
angle graduation of the length of target scale
dials (48).
1. Lower pointers. The two lower pointers
(78) are made of 1/16-inch clear lucite and are
2 3/32 inches in length. They are provided with
clearance holes in their axis point to rotate
over the lower pointer collars (76). The long
and short sections on each side of their axis
taper to 1/4-inch width, with rounded corners.
The long section lower face of each is provided
with an engraved groove of shallow depth in the
centerline which projects inward 1/2 inch and is
filled with red lacquer. The short section of
each is provided with a clearance hole near the
end, countersunk from the lower face to accommodate a lockscrew (71). These lockscrews are
inserted in countersunk clearance holes in each
to attach to a lower pointer knob (79) to their
upper face. The lower pointers are assembled
to the height scale dials over the lower pointer
collars (76), each on a felt friction washer
(81).
2. Upper pointers. The two upper pointers
(73) are made of 1/16-inch clear lucite and are
1.530 inches in length. The wider parts are
1 5/32 inch, with a clearance hole located in the
center of a 5/16-inch radius. They are provided
with three equally spaced countersunk clearance
holes in each lower face for lockscrews (72).
These lockscrews are inserted into tapped holes
in the upper pointer knobs (74) and secured to
each upper face of the pointers.
The upper pointers taper from their wider part
to a 1/4-inch width, with rounded corners. These
wider parts have an engraved groove of shallow
depth in their centerline located in the lower
faces, which projects inward 1/2 inch and is filled
with red lacquer.
The periphery of the upper pointer knob is
knurled to offer a firm grip. It has countersunk
clearance holes in the axis to receive spring
washers (77) and the pointer shoulder screws
(75).
3. Pointer shoulder screws. The two pointer
shoulder screws (75) are made of brass and are
0.700 inch in length. The large diameter forms
the heads, with screw driver slots of appropriate
depth. The medium shoulders fit into the clearance
126
holes in the upper pointer knobs (74) with
assembled spring washers (77) below the heads.
The medium shoulders are provided with
0.030-inch depth tangs to fit into the broached
tang clearance holes of the 1/32-inch brass friction
washers (80). The brass friction washers (80)
remain stationary between the upper pointers
(73) and the lower pointers (78), thus separating
the pointers, and providing sufficient friction to
maintain the setting of the pointers. These
shoulder screws extend into the tapped holes
in the height scale dials' center axis to retain
the complete pointer assemblies.
w. Housing cover plate. The housing cover
plate (69) is made of 1/16-inch brass plate. Its
outer surface conforms to cover the stadimeter
housing center section. Each of the four corners
has a clearance hole that coincides with the
clearance holes for the stadimeter housing
bolts (30). Two clearance holes diagonally
opposite are provided for the inserted dowel
pins (22) projecting upward from the front
and rear side walls.
A clearance hole of appropriate size is provided
at a proper location for the star wheel lock
plunger (62) projecting above the face of the
center section. A large clearance hole of 1 11/32
inches in diameter is provided to fit over the
periphery of the ball bearing retainer (70).
The cover plate is secured to the center section
face with six lockscrews (34). These lockscrews
are inserted into countersunk clearance holes,
properly located in all four sides and screwed
into tapped holes in the four side walls of the
center section. The cover plate covers the transmission center section of the stadimeter housing
(67) after it is filled with mineral grease grade II
medium.
4J9. Disassembly of the stadimeter housing assembly. The stadimeter housing assembly is
disassembled in the following manner:
1. Remove the two alemite fittings (82)
from the front ands rear scale housing section
of the stadimeter housing (67).
2. Remove the six lockscrews (34), unscrewing them from the tapped holes in the four
walls of the center section. Remove the housing
cover plate (69). Check the stadimeter dials;
they should be located at the observing position
referred to by the stamped numerals on the
stadimeter housing.
3. Clean out all grease and wash out the
transmission center section with a grease solvent.
4. Remove the four lockscrews (33) and
remove the star wheel lock plunger housing
(64). This allows the star wheel lock plunger
(62), star wheel key (60), its holder (61), and
the plunger spring (63) to be removed.
5. Remove the four lockscrews (57) and the
ball bearing retainer (70).
6. Remove the transmission shaft pinion
(65), carrying with it vertically the transmission
shaft pinion thrust collar (66), its taper pin
(58), ball bearing (20), female tang coupling
(68), and its taper pin (58). It may be necessary to tap the female tang coupling lightly
with a rawhide mallet around the periphery
to loosen this assembly.
7. Remove the taper pin (58) and the female
tang coupling (68) from the integral stub shaft
section of the transmission shaft pinion (65).
8. Remove the ball bearing (20) from the
integral stub shaft section of the transmission
shaft pinion (65).
9. Remove the taper pin (58) from the transmission shaft pinion thrust collar (66), removing
the thrust collar from the long integral shaft
section of the transmission shaft pinion (65).
Pay particular attention to reference marks
on all gears, as these gears are lapped to make
synchronization of both dial units possible.
10. Remove the taper pin (44) from the star
wheel hub section (59) and remove the lockscrew (36) from the hub section of the transmission shaft bevel tear (5). The woodruff key
(31) remains in the stub section of the handwheel
shaft (23).
11. Remove the taper pin (44) from the hub
section of the handwheel shaft bevel gear. (3),
freeing the handwheel shaft (23) for removal.
12. Remove the handwheel shaft (23) by
grasping the handwheel (12) and pulling it
outward slowly. This allows the transmission
shaft bevel gear (5), handwheel shaft bevel
gear (3), and star wheel (59) to be removed.
127
13. Remove the lockscrew (35) from the hub
section of the handwheel (12), removing the
handwheel from the outer part of the handwheel
shaft (23). The handwheel key (1) can remain
in the shaft.
14. Remove the two spring handle hinge
screws (13) from the countersunk tapped holes
in the scalloped periphery of the handwheel
(12). The spring handle assembly slides out
easily.
15. To disassemble the spring handle assembly, remove the plunger nut (27). Unscrew
this nut from the spring handle plunger (26)
by compressing the plunger spring (29). The
plunger nut can then be removed easily by
hand.
16. Remove the spring handle (25) from the
spring handle stud (24).
17. Using a special wrench, remove the spring
retainer nut (28) from the internal threaded
section in the spring handle stud (24).
18. Remove the plunger spring (29) and the
spring handle plunger (26) from the internal
body section of the spring handle stud (24).
19. Remove the four lockscrews (37) from
the handwheel bracket (6), unscrewing them
from tapped holes in the center section right
side wall. Remove the handwheel bracket.
20. Remove the pointer assembly from the
front scale housing mechanism as follows:
Remove the pointer shoulder screw (75), unscrewing it from the tapped hole axis in the
height scale mount (51). This removes the
pointer assembly of the following: pointer
shoulder screw (75), spring washer (77), upper
pointer knob (74), its lockscrews (72), upper pointer (73), brass friction washer (80), lower
pointer knob (79), its lockscrews (71), lower
pointer (78), lower pointer collar (76), and the
felt friction washer (81).
21. The removal of the pointer assembly
of the rear scale housing mechanism is followed
in similar manner to that described for the front
scale housing mechanism. Refer to Step 20.
22. Remove the front scale housing mechanism as follows: Remove the two length of
target scale knobs (17), unscrewing them from
the tapped holes in the length of target scale
mount (47).
23. Remove the four lockscrews (43) from
the height scale dial (52), six from the range
scale dial (50), and six from the length of target
scale dial (48). A total of 16 lockscrews (43)
is removed.
24. Remove the height scale dial (52),
range scale dial (50), and length of target scale
dial (48).
25. Remove the four lockscrews (39) from
the height scale mount (51). These lockscrews
are unscrewed from the tapped holes in the
scale housing base (9). Precaution must be
taken to observe reference marks on all these
parts upon disassembly in order to reassemble
them correctly later.
26. Insert the pointer shoulder screw (75)
in the tapped hole axis of the height scale
mount (51) tapping the outer wall of the scale
housing section with a light rawhide mallet
and using an outward thrust on the above
screw head and body to remove the height
scale mount.
27. Remove the range scale mount (49),
carrying with it the range scale actuating bevel
gear (11) and the mounted ball bearing (32).
The mount is removed by pulling it out of the
scale housing (9).
28. Remove the four lockscrews (40) from
the small counterbored face of the range scale
mount (49). These lockscrews are unscrewed
from tapped holes in the range scale actuating
bevel gear (11). The ball bearing (32) should
not be removed from the counterbore of the
above bevel gear (11) unless corroded, in which
case it should be pressed out and renewed.
29. Remove the eight lockscrews (42) from
the outer face of the scale housing (9). These
lockscrews are unscrewed from the tapped holes
in the large counterbored face of the scale
housing section.
30. To remove the scale housing (9) it is
necessary to place four fingers of each hand
below the length of target scale mount (47)
and tap the outer wall of the scale housing
section lightly with a small rawhide mallet.
An alternate method is to insert an 8-36 jacking
128
screw in the tapped hole axis in the scale housing,
and slowly jack the scale housing out; it may also
be necessary to use a rawhide mallet to break
the paint seal. The jacking screw rests against
the lower inner wall of the scale housing section.
31. When the scale housing (9) is loosened
from the large counterbore, tip it at an angle,
and follow the first method for its removal.
32. Remove the four retaining screws (7)
from the small periphery shoulder of the scale
housing (9). These retaining screws are unscrewed from countersunk tapped holes in the
scale housing and their protrusion in the undercut groove in the periphery of the length of
target scale mount (47). Remove the length
of target scale mount from the scale housing (9).
33. Remove the two lockscrews (38) from the
index line plate (15). These lockscrews are unscrewed from the tapped holes in the scale
housing outer face (9).
34. The removal of the rear scale housing
mechanism is followed in similar manner to that
described in Steps 22 to 34 inclusive for the front
scale housing mechanism.
35. Remove the taper pin (44) from the
transmission gear pinion (2) and the inner part
of the long transmission shaft (4), and remove
the transmission gear pinion (2).
36. Remove the long transmission shaft (4),
carrying it out of the mounted ball bearing (14)
located in the scale ball bearing housing (8),
carrying with it the range scale actuating bevel
gear pinion (10). It is further carried out of
the ball bearing (14) mounted in the front scale
housing section.
37. Remove the taper pin (45) from the front
range scale actuating bevel gear pinion (10)
and the outer part of the long transmission shaft
(4), and remove the gear pinion (10) from the
shaft.
38. Remove the lockscrew (55) by the
insertion of a long screw driver blade protruding
through the ball bearings (14) mentioned in
Step 37. The lockscrew is unscrewed from
the tapped axis hole in the inner part of the
short transmission shaft (53). Remove the
transmission gear pinion (54).
39. Remove the key (56) from the inner part
of the short transmission shaft (53).
40. Remove the short transmission shaft
(53) carrying it out of the mounted ball bearing
(14) in the scale ball bearing housing (8). It is
further carried out of the ball bearing (14)
mounted in the rear scale housing section,
carrying with it the range scale actuating bevel
gear pinion (10).
41. Remove the taper pin (45) from the rear
range scale actuating bevel gear pinion (10)
and the outer end of the short transmission shaft
(53) and remove the gear pinion (10) from the
shaft.
42. Remove the two lockscrews (41) from
each of the two transmission ball bearing housings (21). Remove the assembled ball bearings
(20) with their housings.
43. Remove the two lockscrews (41) from
each of the two scale ball bearing housings (8).
Remove the assembled ball bearings (14) with
their housings.
44. Remove the two ball bearings (14) from
the front and rear scale housing section walls,
and remove the one ball bearing (20) from the
right side wall of the center section. Remove the
ball bearing (20) from the raised semi-circular
section in the center section base. This ball
bearing is removed by inserting a special pair
of calipers in the center clearance hole of the
center race, allowing the calipers to get below
the center race, and tapping on the stadimeter
housing with a small rawhide mallet while an
upward thrust is maintained with the calipers.
45. The length of target scale clamp screws
(16) are not removed from the retaining collars
(18) mounted in the right side of each scale
housing (9), as this removal would necessitate
drilling out the retaining collar rivets (19).
46. Clean all parts thoroughly with a grease
solvent.
4J10. Reassembly of the stadimeter housing assembly. The stadimeter housing assembly is
reassembled as follows:
1. Apply Lubriplate No. 110 lightly to all
rotating parts as the reassembly procedure is
followed.
129
2. Various parts have reference numerals
with mating numerals stamped in or on the
various parts to establish coincidence of these
parts for correct reassembly.
3. Place the two ball bearings (14) in the
front and rear scale housing section walls of
the stadimeter housing (67).
4. Place one ball bearing (20) in the right
side wall of the center section, and one in the
raised semi-circular section in the center section
base. Tap this bearing all the way in until it
touches the bottom.
5. Place the two transmission ball bearing
housings (21) with the mounted ball bearings
(20) at their respective places on the upper face
of the raised G-wall section in the center section.
The dowel pins of each housing base fit into
aligning holes. Secure these two housings with
two lockscrews (41) each. These lockscrews
are inserted into two countersunk clearance
holes in each housing and screwed into tapped
holes in the raised G-wall section.
6. Place the two scale ball bearing housings
(8) with the mounted ball bearings (14) in
their respective places on the upper face of the
raised G-wall section in the center section.
These two housings are located perpendicular
to the two assembled transmission ball bearing
housings (21). The dowel pins of each housing
base fit into aligning holes. Secure these two
housings with two lockscrews (41) each. These
lockscrews are inserted into two countersunk
clearance holes in each housing and screwed into
tapped holes in the raised G-wall section.
7. Place the rearrange scale actuating bevel
gear pinion (10) on the outer end of the short
transmission shaft (53) and secure it by the
insertion of a taper pin (45). The insertion of
the taper pin should be done with the gear
pinion hub held on a soft metal V-block.
8. Insert the short transmission shaft (53)
from the rear scale housing section side into
the first mounted ball bearing (14), carrying it
farther through the second mounted ball bearing
(14) in the scale ball bearing housing (8). The
shaft is a push fit into both ball bearings.
9. Insert the key (56) in the keyway in the
short transmission shaft inner part (53).
10. Place the transmission gear pinion (54)
on the short transmission shaft (53) over the
inserted key (56). Secure it with a lockscrew
(55), screwing it tight by the use of a long screw
driver blade inserted from the front scale housing
section, and protruding through the two mounted
ball bearings (14).
11. Place the front range scale actuating
bevel gear pinion (10) on the outer end of the
long transmission shaft (4) and secure it by the
insertion of a taper pin (45). The insertion of
the taper pin should be done with the gear pinion
hub held on a soft metal V-block.
12. Insert the long transmission shaft (4)
from the front scale housing section side into
the first mounted ball bearing (14) carrying it
farther through the second mounted ball bearing
(14) of the scale ball bearing housing (8). The
shaft is a push fit into both ball bearings.
13. Place, the transmission gear pinion (2)
on the long transmission shaft inner part (4)
and secure it with a taper pin (44).
14. Place the handwheel bracket (6) on the
alignment recess of the right side wall of
the stadimeter housing center section. Secure the
bracket with four lockscrews (37) which are
inserted into countersunk clearance holes in
the bracket and screwed into tapped holes in
the center section right side wall.
15. Insert the handwheel key (1) in the
outer part of the handwheel shaft (23), and
assemble the handwheel (12) over the inserted
key and this part of the handwheel shaft. Secure
the handwheel (12) with a lockscrew (35). This
lockscrew screws into the tapped hole in the
handwheel hub section and extends into the
spotted recess in the handwheel shaft.
16. Place the handwheel shaft (23) through
the first mounted ball bearing (20) in the transmission center section. The shaft is a push fit
in this ball bearing.
17. Place the star wheel (59) with its hub
section toward the handwheel (12) on the handwheel shaft (23).
18. Push the handwheel shaft (23) through
the second mounted ball bearing (20) of the
transmission ball bearing housing (21). The shaft
is a push fit in this ball bearing.
130
19. Place the handwheel shaft bevel gear (3)
on the handwheel shaft (23) with its hub section
facing toward the handwheel (12).
20. Push the handwheel shaft (23) through
the third mounted ball bearing (20) in the
transmission ball bearing housing (21). The
shaft is a push fit in this ball bearing.
21. Place the transmission shaft bevel gear
(5) on the stub section of the handwheel shaft
(23) over the inserted woodruff key (31) with
its hub section facing toward the handwheel
(12). Secure the bevel gear (5) by the insertion
of the lockscrew (36), which is screwed into a
tapped hole in the hub section and extends into
the spotted recess in the handwheel shaft
(23). The handwheel hub should be in contact
with the hub section of the handwheel bracket
(6).
22. Slide the star wheel (59) on the handwheel
shaft and line up the taper pin holes. Secure
the star wheel with the insertion of the taper
pin (44).
23. Reassemble the front scale housing mechanism as follows: Place the index line plate (15)
on the scale housing (9) opposite the conical
wall clearance hole, and secure it with two
lockscrews (38). These lockscrews are inserted
into countersunk clearance holes in the plate
and screwed into, tapped holes in the scale housing large shoulder flange.
24. Place the length of target scale mount
(47) in the counterbored seat in the scale housing
(9). Secure the mount with four lockscrews (7).
These lockscrews are inserted in countersunk
tapped, holes in the scale housing shoulder
periphery and screwed into the undercut groove
in the mount periphery.
25. Place the scale housing (9) in the front
scale housing section counterbored seat, tipping
it sufficiently to allow the conical wall clearance
hole, adequate clearance over the range scale
actuating bevel gear pinion (10). The scale
housing is a push fit into its counterbored seat.
Secure the scale housing with eight lockscrews
(42) which are inserted into countersunk clearance holes in the scale housing and screwed into
tapped holes in the scale housing section counterbored seat.
26. Assemble the range scale mount to the
range scale actuating bevel gear (11) recess
seat, checking reference marks for proper
coincidence of mating reference marks. Secure
the mount with four lockscrews (40) which
are inserted in clearance holes in the small
counterbored shoulder in the mount and screwed
into tapped holes in the bevel gear.
27. Rotate the front range scale actuating
bevel gear pinion (10) until its reference tooth
is down, so that upon the assembly of the range
scale actuating bevel gear (11) the reference
tooth opening of this bevel gear is upward for
its engagement with the reference tooth of the
gear pinion (10).
28. Place the range scale actuating bevel gear
(11) and the assembled range scale mount (49)
in the scale housing (9) tipping it slightly and
properly meshing it with the front range scale
actuating bevel gear pinion (10) as outlined in
Step 27. Ascertain the central position of this
assembly by checking the coincidence of the
ball bearing race (32) and the small shoulder
counterbore of the scale housing (9).
29. The height scale mount (51) should be
pushed slowly into the range scale actuating
bevel gear ball bearing (32) and farther into
the small shoulder counterbore in the scale
housing (9). The small shoulder seat of the mount
rests against the center ball bearing race and is
secured with four lockscrews (39). These lockscrews are inserted into countersunk clearance
holes in the mount and screwed into tapped holes
in the scale housing lower wall. This retains
the small shoulder seat of the mount snugly
in contact with the center ball bearing race
with sufficient tension to maintain it stationary.
30. Reassemble the rear scale housing mechanism by following Steps 23 to 29 inclusive.
31. Check the reference marks of the range
and height scale mounts for the front and rear
scale housing mechanisms and note their relation.
Should both appear in unison, assemble the
range and height scale dials (50 and 52) to
their respective mounts of the front and rear
scale housing mechanisms over the inserted
dowel pins (46). Check the 2.2 numeral graduation on the range scale dial (50). It should
appear approximately opposite the value 58
131
numeral graduation on the height scale dial
(52). Values opposite the numbers 2.2 and 58
are found on Figure 2-12. Refer to both sets of
dials, noting their proper relation. Should both
appear in unison, further assembly is to be
continued.
32. With both sets of dials in unison, the
handwheel shaft bevel gear (3) is now closely
observed for reference marks. This bevel gear
has two reference marks on opposite sides to
engage with a reference tooth of the transmission gear pinions (2 and 54).
33. Properly engage the handwheel shaft
bevel gear (3) reference marks with the reference
tooth of each transmission gear pinion. Insert a
temporary screw in the hub of the bevel gear
which has a tapped hole for this purpose, and
secure the temporary screw. Rotate the handwheel (12) and check both sets of scale housing
dials through the complete series of range
graduations. Should observations denote the
unison of both sets of dials, observe the taper
pin holes of the handwheel shaft bevel gear (3)
and the handwheel shaft (23). They should be
in coincidence. However, by releasing the
temporary lockscrew and holding the bevel
gear in mesh with the gear pinions, the handwheel shaft (23) is rotated for the insertion of
the taper pin (44). The taper pin secures the
bevel gear to the handwheel shaft.
34. Secure the front and rear range scale dials
(50) with six lockscrews (43) each. These lockscrews are inserted into countersunk clearance
holes in the dials and screwed into tapped
holes in their mounts.
35. Secure the front and fear height scale
dials (52) with four lockscrews (43) each. These
lockscrews are inserted in countersunk clearance
holes in the dials and screwed into tapped holes
in their mounts.
36. Place the length of target scale dials
(48) on their respective mounts, and secure
each with eight lockscrews (43). These lockscrews
are inserted into countersunk clearance holes
in the dials and screwed into] tapped holes in
their mounts.
37. Place the sets of length of target scale
knobs (17) in opposite sides of each length
of target scale dials (48). These knobs are
inserted into clearance holes in the dials and
screwed into tapped holes in the mounts.
38. Reassemble the front pointer assembly to
the front scale housing mechanism as follows:
Place the spring washer (77) over the medium
shoulder of the pointer shoulder screw (75).
39. Secure the upper pointer (73) to the upper
pointer knob (74) with three lockscrews (72).
40. Place the pointer shoulder screw (75)
with the spring washer (77) in the upper pointer
knob (74).
41. Place the brass friction washer (80) on
the pointer shoulder screw (75) aligning the flat
part of the broached hole on the undercut
shoulder.
42. Place the lower pointer collar (76) on
the pointer shoulder screw (75).
43. Place the lower pointer knob (79) on
the lower pointer (78) and secure it with a
lockscrew (71). Place the lower pointer collar
(76) on the pointer shoulder screw (75).
44. Place the felt friction washer (81) on
the lower pointer collar (76) and the pointer
shoulder screw (75).
45. Place the front pointer assembly at the
axis of the height scale dial, and screw the
pointer shoulder screw into the tapped axis hole
in the height scale mount (51). Check the relation of the upper pointer to the lower pointer.
If the brass friction washer is engaged properly
on the pointer shoulder screw (75), a proper
friction setting for the upper and lower pointers
exists.
46. Reassembly of the rear pointer assembly
to the rear scale housing mechanism is followed
in similar manner to that described in Steps
38 to 45 inclusive for the front scale housing
mechanism.
47. Place the transmission shaft pinion thrust
collar (66) on the long integral shaft section of
the transmission shaft pinion (65) and secure
it by the insertion of a taper pin (58).
48. Place the ball bearing (20) on the integral
stub section of the transmission shaft pinion
(65), allowing the ball hearing to contact the
pinion.
132
49. Place the female tang coupling (68)
over the male tang section of the integral stub
section of the transmission shaft pinion (65),
allowing the female tang coupling to contact
the assembled ball bearing (20), and secure
the coupling with the insertion of a taper pin
(58).
50. With the dials of both front and rear scale
housing mechanisms set to the observing position, place the transmission shaft pinion assembly vertically in the center section. It is
carried through the ball bearing hole in the
semi-circular lug section. The flat tang section
in the female tang coupling (68) faces toward
the handwheel (12), and the pinion is engaged
into the transmission shaft bevel gear (5) as
the long integral shaft section is pushed into
the mounted ball bearing (20) in the raised
semi-circular section of the center section base.
51. Assemble the ball bearing retainer (70) to
the semi-circular lug section face of the center
section over the female tang coupling (68) and
secure with four lockscrews (57).
52. Check the mesh of all pinions and bevel
gears for the detection of backlash or shallow
depth of the teeth. A careful observation readily
determines where shimming is required for a
snug working depth of mating pinions and
bevel gears.
53. Reassemble the automatic stop assembly
into the center section as follows: Place the star
wheel key (60) in the star wheel key holder
(61), and secure it with the insertion of a taper
pin (44).
54. Place the star wheel key (60) and its
holder (61) with the star wheel lock plunger
spring (63) below the handwheel shaft (23),
engaging the key in the star wheel (59).
55. Place the star wheel lock plunger (62)
in the star wheel lock plunges housing (64)
and assemble them over the handwheel shaft
(23). Carefully check the plunger housing as it
is lowered to the center boss section. Secure
the plunger housing with four lockscrews (33).
56. The automatic stop assembly should be
locked at the observing position for its assembly
to the base of the eyepiece box (11, Figure 4-29).
57. Fill the center section with soft mineral
grease grade II medium.
58. Place the housing cover plate (69) on
the center section, and secure it with six lockscrews (34). These lockscrews are inserted in
countersunk clearance holes in the housing
cover plate and screwed into tapped holes in
the four center section walls.
59 Screw both alemite fittings into the lower
part of the front and rear scale housing section
walls, filling the housings with soft mineral
grease grade II medium.
60. Reassemble the spring handle assembly
as follows: Insert the spring handle plunger (26)
in the spring handle stud (24).
61. Place the plunger spring (29) over the
spring handle plunger (26) and into the large
counterbored section in the spring handle stud
(24).
62. Place the spring retainer nut (28) over
the spring handle plunger (26). Using a special
wrench, compress the plunger spring (29) so
that the retainer nut engages in the internal
threaded section in the spring handle stud (24)
until it is flush with the face.
63. Place the spring handle (25) over the
spring handle stud (24).
64. To apply the spring handle plunger nut
(27), press downward on the spring handle
plunger (26), applying pressure with the spring
handle (25). Screw on the spring handle plunger
nut, securing it with a special wrench.
65. Place the spring handle assembly in the
hinge opening in the side wall of the handwheel
(12). Insert the two spring handle hinge screws
(13). These hinge Screws are screwed into
countersunk tapped holes in the handwheel
scalloped periphery and extend into reamed
holes in each side of the spring handle stud (24).
4J11. Description of the operation of the range
and course angle finder. operation of the range
and course angle finder is accomplished in the
following manner:
The clockwise rotation of the handwheel
(12, Figure 4-24) transmits motion to the handwheel shaft (23) to operate the handwheel shaft
bevel gear (3). The clockwise rotation of this
133
handwheel shaft bevel gear (3) transmits counterclockwise rotation to the front transmission
gear pinion (2) and clockwise rotation to the
rear transmission gear pinion (54) in mesh
with this bevel gear at right angles.
The counterclockwise rotation of the front
transmission gear pinion (2) carries the long
transmission shaft (4) in the same direction as
the front range scale actuating bevel gear
pinion (10) on the opposite end of this shaft.
The counterclockwise rotation of the front
range scale actuating bevel gear pinion (10)
in mesh with the front range scale actuating
bevel gear (11) transmits motion to this bevel
gear, causing it to rotate clockwise. It carries
the attached range scale mount (49) and its
range scale dial (50) clockwise.
The rear scale housing mechanism operates
opposite to the front scale housing mechanism
when the observer is located in the front of the
periscope. However, relatively speaking, it
operates similarly to the front scale housing
mechanism, were the observer to be stationed
on the rear side of the instrument.
The clockwise rotation of the handwheel
shaft (23) operates the transmission shaft
bevel gear (5) clockwise. This bevel gear in
mesh with the transmission shaft pinion (65)
and at right angles to it, operates the pinion
clockwise, observing this pinion from the lower
end. The clockwise rotation of the handwheel
shaft (23) simultaneously operates the front
and rear scale housing mechanisms and the
transmission shaft pinion (65).
Clockwise rotation of the transmission shaft
pinion (65) carries its attached female tang
coupling (68) in the same direction. The female
tang coupling (68) coupled with the stadimeter
transmission shaft (22, Figure 4-27) carries
it clockwise, as does also its interconnection
with the operating gear pinion shaft (13, Figure
4-23) and its attached operating gear pinion (12).
The clockwise rotation of they operating gear
pinion (12) in mesh with the operating gear (1),
causes it to rotate counterclockwise. The
cam grooves of the operating gear (1) in the
counterclockwise rotation looking upward from
the lower part of the instrument cause the cam
shoes (4) attached to mounting plate guide
keys and integral shafts (15) to displace the
mounting plate halves (5) and the attached
lower (split) objective lens and mount halves
(see Figure 4-22). The displacement of the lower
(split) objective lens halves causes duplicate
images to be produced, so that, for example, the
waterline of one image may be brought into
contact with the masthead or funnel top of the
other image. The angle subtended is indicated
in terms of yards on the range scale dial (50,
Figure 4-24) and against the known height on
the stationary height scale dial (52).
The grooves in the operating gear are cut so
that the lateral movement of the lower (split)
objective lens halves is proportional to the
logarithm of the tangent of the angle through
which the operating gear is rotated.
With the handwheel (12, Figure 4-24) rotating
clockwise, the operating ear is rotated counterclockwise. The operating gear stop (19, Figure
4-23) moves with the operating gear (1) and
leaves its contact with the observation position
stop (20).
Actuation from the vertical range observing
position is accomplished when the (split)
lens halves function as a single lens, until the
operating gear (1) travels through approximately
147 degrees of rotation and contacts the maximum
displacement stop (20), thereby causing the
optical axis of each half to be displaced from
the periscope axis an amount equal to the movement of each half. The axis of each half remains
parallel to the periscope axis, and the principal
focal plane of each objective lens half remains
in the same plane as before splitting.
Further clockwise rotation of the handwheel
(12, Figure 4-24) causes the sliding track
(3, Figure 4-23) to which the maximum displacement stop (20) is secured by the operating gear
retaining ring (35), to rotate through 90 degrees inside
the track sleeve (2). The maximum displacement stop (20) located on the operating gear
retaining ring (35) absorbs the torque required
to lift the range position detent pawl (7) against
spring pressure of the detent pawl spring (6)
by the movement of the detent pawl rest (8)
attached to the sliding track (3).
The 90 degrees rotation of the sliding track (3, Figure
4-23) counterclockwise is accomplished by the
134
128 degrees circumferential slot of the track sleeve (2).
This 90 degrees rotation ends when the detent pawl
rest (8) comes into contact with the end of the
128 degrees slot in the track sleeve (2), and engages a
locking device for the course angle position
detent pawl (7).
Turning the handwheel (12, Figure 4-24)
counterclockwise causes the operating gear (1)
and its stop (19, Figure 4-23) to rotate clockwise
and make the two lens halves approach each
other. The known length of target having been
set on the length of target scale dial (48, Figure
4-24) opposite the index mark on the scale
housing (9), the course angle is indicated on the
length of target scale dial against the previously
found range on the range scale dial (50), when
the bow of one image touches the stern of the
other.
In clockwise rotation, the operating gear
stop (19, Figure 4-23) loses contact with the
maximum displacement stop (20) and is carried
with the operating gear (1) until it contacts
the observation position stop (20) in which
position the split lens functions again as a single
lens. This return movement is approximately
147 degrees traversed previously in the counterclockwise rotation to obtain maximum displacement but giving the course angle single
image position.
Further counterclockwise rotation of the
handwheel (12, Figure, 4-24) causes the sliding
track (3, Figure 4-23) to which the observation
position stop (20) is secured to the operating
gear retaining ring (35), to rotate through 90 degrees
inside the track sleeve (2). The observation
position stop (20) located on the operating gear
retaining ring, (35) absorbs the torque required
to lift the course angle position detent pawl (7)
against the tension of the detent pawl spring
(6) by the movement of the detent, pawl rest
(8) attached to the sliding track (3).
The 90 degrees return clockwise rotation of the sliding
track (3) is accomplished by the 128 degrees circumferential slot in the track sleeve (2) This 90 degrees
rotation ends when the detent pawl rest (8)
comes into contact with the end of the 128 degrees
slot in the track sleeve (2), and engages a locking
device for the range position detent pawl (7).
Thus the observations are resumed as desired
from the range position again.
Collimation of the lower (split) objective lens
and mount assembly (Figure 4-22), the objective
operating mechanism assembly (Figure 4-23),
and the stadimeter housing assembly (Figure
4-24) is described under Section 4V9.
4J12. Steps necessary to obtain range and course
angle of a vessel. The range and course angle of a
vessel may be found in the following manner:
1. The estimated length and height of the
target must be known.
2. Set the length of target on the length of
target scale dial (48, Figure 4-24) against the
stationary index line mark. Clamp the outer
scale by means of the locking clamp screw (16).
3. Set the estimated height of the target
with a pointer.
4. Starting with the split objective lens as a
whole lens in the observing position, first bring
the target approximately into the center of the
field of view. Rotate the handwheel (12) clockwise until the masthead of the object or target
in one image coincides with the waterline in the
other image.
5. Resume turning the handwheel (12) clockwise to the limit of its travel. At this point, the
lower (split) objective lens is carried through
a 90 degrees rotation.
6. Upon reaching the end of this 90 degrees rotation,
the handwheel (12) is reversed or turned
counterclockwise, stopping when the bow of
the target of one image coincides with the stern
of the other image.
7. Read the course angle on the inner scale
of the length of target scale dial (48) against
the range in yards on the range scale dial (50).
8. Continue counterclockwise rotation until
the lens halves again function as a single lens
at the observing position.
4J13. Operation of the stadimeter. The following
problem illustrates the use of the stadimeter.
Figure 4-25 shows the stadimeter setting for a
target vessel whose height from waterline to
masthead is known to be 60 feet, and whose
length from bow to stern is known to be 375
feet. Find the range and course angle of the
target.
135
First set the length of the target on the length
of target scale dial against the index mark, and
clamp the length of target scale dial and mount
by the locking clamp screw. Then, starting
with the stadimeter at the observing position,
bring the target approximately into the center
of the field of view. Rotate the handwheel
clockwise until the masthead of the target in
one image coincides with its waterline in the
other image. At this point, the scale dials are
shown in Figure 4-25, and the range (2300 yards)
is read on the range scale dial, opposite the
height (60 feet) on the height scale dial.
Turn the handwheel clockwise to the limit
of its travel; then reverse the direction, stopping
when the bow of the target in one image coincides
with the stern in the other image. The position
of the scale dials at this stage is shown in Figure
4-26. The course angle (20 degrees) is read on the inner
scale on the length of target scale dial, against
the range (2300 yards) on the range scale
dial. The angle thus found is measured from the
line of sight of the periscope. Note that the course
angle is measured without regard to the direction
of movement of the target, and may be either
the angle observed, or its supplement, in this
case 160 degrees.
Figure 4-25. Operation of stadimeter for obtaining
the range of an individual problem.
Figure 4-26. Operation of stadimeter for obtaining
the course angle of previous problem.
By continuing the counterclockwise rotation
of the handwheel to the limit of its travel,
restore the periscope to the observing position,
ready for the next observation.
The following hints may be of value:
1. Remember that the stadimeter measures
only angles, and computes the range on the
basis of the known height (and length in
the case of course-angle measurements). If the
height must be assumed, the range reading can
be no more accurate than the estimate of the
height. If both height and length are assumed,
the course-angle reading thus obtained is subject
to a large error.
2. The dimensions selected for these observations should be those which are known, or which
can be estimated, with fair accuracy. In addition,
the reference points, in so far as possible, should
be definite, easy to see, and widely spaced. The
masthead and waterline, for example, while
affording the greatest vertical dimension, might
both be invisible at long range.
3. The stadimeter is graduated up to 11,000
yards. Longer ranges may be obtained by
remembering that the angle subtended by 80
feet, for example, at 20,000 yards, is the same
as that subtended by 40 feet at 10,000 yards.
Thus an object 80 feet high may be set up at
the 40-foot line and the range multiplied by two.
136
4. The stadimeter scale dials are graduated
for use with the periscope in high power. When
necessary to range on an object more than 130
feet high, the stadimeter may be used with the
periscope in low power, and the object set up
on the height scale dial at one-fourth its actual
height. The range reading is then correct.
5. Difficulty may at first be encountered in
centering the eye in order to see the duplicate
images with equal intensity. To a great extent,
practice overcomes this difficulty. On bright
days the use of one of the rayfilters permits the
pupil of the eye to expand and intercept a greater
portion of the divided exit pupil.
6. A stadimeter range may be taken with a
periscope exposure of a few seconds. It is assumed
that the approximate bearing of the target is
known, and that the reference points have been
selected. The known or estimated height between
the reference points should be set in advance on
the height scale dial. Use the pointer if one is
provided, or a crayon mark. The periscope may
be trained approximately on the target, the
power shift placed in high power, and the focus
set for the observer's eye. In addition, the
estimated range may be set up on the stadimeter.
All this may be done with the periscope partially
housed. If the periscope is then exposed, no
time is lost in focusing, and little in centering
the object and bringing the reference points
into coincidence. When this is done the instrument may again be partially housed and the
range reading taken. Practice is essential to
the efficient operation of the stadimeter.