1. Using an air hose, blow out the upper telescope system Part II consisting of the second, third, and fourth inner tube sections (Figure 4-21).

2. Screw the threaded periphery of the upper part of the fourth inner tube section upper end coupling (5) into the internal threaded section in the lower part of the fifth inner tube section (34, Figure 4-20) of the upper telescope system Part I.

3. Insert and secure the four lockscrews (35), inserting them in countersunk clearance holes in the lower part of the fifth inner tube section (34) and screw them into tapped holes in the upper alignment support section of the fourth inner tube section upper end coupling (5, Figure 4-21). This secures the upper telescope system Part I and Part II together.

4V2. Reassembly of the lower telescope system. The lower telescope system is reassembled in the following manner:

1. Connect the eyepiece skeleton assembly (Figure 4-28) to the lower part of the first inner tube section assembly (Figure 4-27).

3. Insert and secure the four lockscrews (37, Figure 4-28), inserting them in countersunk clearance holes in the counterweight bearing section of the eyepiece skeleton (42) and screw them into tapped holes in the spider bearing lower alignment support section (3, Figure 4-27).

4. Connect the objective operating mechanism assembly (Figure 4-23) to the first inner tube section assembly (Figure 4-27).

5. Screw the internal threaded section in the lower part of the track sleeve (2, Figure 4-23) on the threaded periphery located in the upper part of the first inner tube section upper end coupling (11, Figure 4-27).

6. Insert and secure the four lockscrews (23, Figure 4-23), inserting them in countersunk clearance holes in the lower part of the track sleeve (2) and screwing them into tapped holes in the upper alignment support section of the first inner tube section upper end coupling (11, Figure 4-27). This secures the objective operating mechanism assembly and the first inner tube section assembly together.

8. Place the objective operating mechanism assembly and the eyepiece skeleton assembly attached to the first inner tube section assembly in two V-blocks on the optical I-beam bench.

9. Unscrew the eyepiece lens mount (19, Figure 4-28), carrying with it the eyepiece lens (52), eyepiece lens clamp ring (16), and its lock screw (41). The removal of the above outward projecting assembly is necessary for the assembly of the eyepiece box (11, Figure 4-29) to the eyepiece skeleton (42, Figure 4-28).

10. Check the base of the eyepiece box (11, Figure 4-29) to ascertain that the eyepiece skeleton centering screw (12) is not secured in place.

11. Assemble the outer tube and eyepiece box rubber gasket (8) on the upper alignment support section of the eyepiece box (11), resting it against the sealing shoulder located preceding the threaded periphery. Check the eyepiece box and eyepiece skeleton assembly to ascertain the elimination of all inward and external projecting parts and to make sure that nothing restricts the assembly of the eyepiece box (11).

12. Place the eyepiece box (11) over the eyepiece skeleton assembly (Figure 4-28), guiding it on slowly and carefully. It is carried on the narrow alignment shoulder of the large shoulder flange of the eyepiece skeleton (42). Engage the reamed dowel pin holes of the eyepiece box upper face over the downward protruding dowel pins (36) in the eyepiece skeleton large shoulder flange.

13. Insert and secure the eight lockscrews (31). These lockscrews are inserted with the counterweight (25) at its extreme upward position. The lockscrews are inserted in the clearance holes in the eyepiece skeleton (42) large shoulder flange and screwed into tapped holes in the upper face of the eyepiece box (11, Figure 4-29).

14. Place the stadimeter transmission shaft (22, Figure 4-27) in the stuffing box section of the eyepiece box face (11, Figure 4-29).

15. Place the lower thrust collar (4, Figure 4-27) on the stadimeter transmission shaft (22) and carry the shaft through the bearing hole in the spider (2).

16. Place the upper thrust collar (4) on the stadimeter transmission shaft, (22) and carry the shaft upward through the clearance hole in the soldered bracket (23) located on the central part of the first inner tube section periphery (1).

17. Line up the position of the taper pin holes in the stadimeter transmission shaft coupling (14, Figure 4-23) and the stadimeter transmission shaft (22, Figure 4-27). Insert two temporary lockscrews in tapped holes in the coupling until completion of procedure stated in Section 4V11.

18. Place the two thrust collars (4) next to the side faces of the cast bearing projection of the spider (2) and secure them with two taper pins (10).

19. Place the eyepiece drive packing gland assembly stuffing box body gasket (11, Figure 4-35) on the counterbored face of the eyepiece box (11, Figure 4-29) for this assembly.

20. Place the counterweight (25, Figure 4-28) at the extreme upward limit of its travel (the plus position).

21. Place the female coupling section (3, Figure 4-39) of the focusing knob assembly on the square section of the eyepiece drive actuating shaft (12, Figure 4-35) of the eyepiece drive packing gland assembly. Check the reference punch mark on the eyepiece drive actuating shaft (12) and the corresponding reference mark on the female coupling section (3, Figure 4-39) for proper alignment.

22. Check the +1 1/2 diopter setting with the stationary zero reference line of the knob bracket hub (7). The +1 1/2 diopter setting should be turned to a slight overtravel of the stationary zero diopter reference line.

23. Place the eyepiece drive packing gland assembly together with the attached focusing

24. The eyepiece drive mechanism bevel gear (1) attached to the eyepiece drive actuating shaft (12) should engage into mesh correctly with the eyepiece prism shift bevel gear (11, Figure 4-28) of the eyepiece skeleton assembly.

25. Remove the focusing knob assembly (Figure 4-39) from the eyepiece drive packing gland assembly (Figure 4-35).

26. Rotate the stuffing box body of the eyepiece drive packing gland assembly so that reference numerals on the stuffing box body flange face coincide with the reference numerals on the eyepiece box recess face (11, Figure 4-29).

27. Insert and secure the six lockscrews (3, Figure 4-35) inserting them into countersunk clearance holes in the stuffing box body flange (6) and screwing them into tapped holes in the eyepiece box counterbored seat.

28. Replace the focusing knob assembly (Figure 4-39) on the square section of the

Figure 4-50. Special eyepiece alignment jig diagram.

29. Check the rectangular flange of the knob bracket (7, Figure 4-39) to ascertain that the two dowel pins (8) engage in the dowel pin holes in the eyepiece box recess face.

30. Insert and secure the four lockscrews (10). These lockscrews are inserted in countersunk clearance holes in the knob bracket rectangular flange (7) and screwed into tapped holes in the eyepiece box.

31. Place the eyepiece skeleton centering screw lead washer (13, Figure 4-29) on the shoulder of the centering screw (12), inserting the centering screw in the base of the eyepiece box (11). The centering screw extends into the reamed hole in the eyepiece skeleton base (42, Figure 4-28) and screws into a tapped hole in the eyepiece box base. Secure the centering screw with a large screw driver blade, using a small wrench on the blade, to insure the hermetical seal of this opening.

32. Using a special wrench attached to the male tang section of the stadimeter transmission shaft (22, Figure 4-27) rotate the shaft, placing the objective operating mechanism at the observing position.

4V3. Alignment of the 90 degrees rotation of the objective operating mechanism. The 90 degrees rotation of the objective operating mechanism is aligned in the following manner:

1. Place the lower telescope system described in Section 4V2 in two V-blocks on the optical I-beam bench. Face the objective operating mechanism toward the end of the optical I-beam bench.

2. With the two special clamp brackets attached to the V-blocks, line up the eyepiece end of this assembly with the horizontal and perpendicular plane of the optical I-beam bench.

3. Place the threaded periphery of the special eyepiece alignment jig (Figure 4-50) in the internal threaded section in the eyepiece prism front retaining plate (24, Figure 4-28) of the eyepiece skeleton assembly. Screw the jig into this front retaining plate until the shoulder of the

Figure 4-51. Lining up the eyepiece jig with machinist's square.

jig attains a tight metal to metal contact with the projecting cylindrical shoulder of this retaining plate.

4. Using a large machinist square, line up the special eyepiece jig to a true horizontal plane. The outer face of the alignment jig is aligned vertically with the vertical blade of the square in the following-manner:

5. Rotate the complete assembly in the V-blocks until the outer face of the alignment jig is parallel to the vertical blade of the square (Figure 4-51). The base of the square is placed on the I-beam surface with the 90 degrees blade extending upward vertically.

6. Secure the V-block clamps by turning the adjusting knobs as shown on the above illustration. These clamp the lower telescope system tight in the V-blocks. Check the face of the alignment jig note and correct any change which may have taken place while clamping.

7. When the special eyepiece jig is in a true horizontal plane and well clamped] determine the parallelism of the observing position of the sliding track (3, Figure 4-23) in the following manner:

8. Rotate the special wrench attached to the male tang section of the stadimeter

transmission shaft (22, Figure 4-27) until the peripheries of the mounting plates (5, Figure 4-23) of the objective operating mechanism are in coincidence.

9. Insert the 90 degrees alignment straight-edge (Figure 4-52) with the four extension lugs of the straight-edge a push fit in the opposite elongated slots of the sliding track large shoulder flange (3, Figure 4-23). The straight-edge of this device locks the mounting plates (5) and the operating mechanism to provide only the 90 degrees rotation.

10. Using a dial indicator attached to a surface gage, determine the parallelism of the straight-edge with the horizontal surface of the optical I-beam bench.

11. Place the surface gage on the surface of the optical I-beam bench, with the dial indicator, set with sufficient tension on the straight-edge (Figure 4-53).

12. Keep a firm pressure on the base of the surface gage while checking throughout the length of the straight-edge.

13. Note the dial indicator for any variation while traveling the length of the straight-edge (Figure 4-54).

14. If variation is noticed, it indicates that wear has taken place at the detent pawl rest stop, which is the end of the circumferential slot of the track sleeve (2, Figure 4-23) for the observing position.

15. Remove the six lockscrews (26), unscrewing them from the tapped holes in the opposite raised mounts of the track sleeve (2). Remove the detent pawl spring (6), and swing the detent pawl (7) clear for the removal of the detent pawl rest (8)

16. Remove the two long and two short lockscrews (9 and 1-0), unscrewing then from the tapped holes in the sliding track (2). Remove the detent pawl rest (8).

17. The detent pawl rest (8) can be built up by welding or it can be renewed. If built up by welding, it can be worked down on a grinding wheel, using a trial and error checking method.

18. After building up the detent pawl rest (8), grind it down until it contacts the end of the track sleeve circumferential slot (2), leaving the straight-edge parallel with the surface of the optical I-beam. Use the dial indicator each time in the same manner as directed in step (13), and secure the detent pawl rest (8) each time with the long and short lockscrews (9 and 10).

Figure 4-54. Dial indicator attached to surface gage on 90 degrees straight-edge at the right side for range position.

19. The opposite stop, or end, of the circumferential slot in the track sleeve (2) is the contact stop position of the opposite face of the detent pawl rest (8) in the course-angle position.

20. The course-angle stop position of the circumferential slot in the track sleeve (2) has minor usage in the service. Therefore, no building up of the detent pawl rest (8) should be required.

21. Turn the special wrench attached to the male tang section of the stadimeter transmission shaft (22) clockwise until the course angle of the detent pawl rest ( 8) is against the end of the circumferential slot in the track sleeve (2).

22. Place the machinist square on the surface of the optical I-beam bench and slide the blade of the square in contact with the straight-edge (Figure 4-55). Check the parallelism of the straight-edge with the 90 degrees vertical blade of the square.

23. Build up and grind down this contact face of the detent pawl rest (8, Figure 4-23) for the course-angle position by following the procedure stated under Step 18; in this case, however, the square is used each time.

25. Swing the detent pawls (7) inward, and check their engagement in the 90 degrees V-groove notch in the detent pawl rest (8) for the observing and course-angle positions. The detent pawls should retain the detent pawl rest against the opposite circumferential slot stops for either position. Should the detent pawls (7) require building up for proper engagement, they can be repaired in the same manner as the detent pawl rest (8).

26. Swing the detent pawls (7) inward and place the spring (6) so that it overlaps both detent pawls. Secure it to the opposite raised mounts of the track sleeve (2) with six lockscrews (26).

27. Remove the straight-edge from the sliding track (3), and rotate the special wrench attached to the male tang section of the stadimeter transmission shaft (22, Figure 4-27) counter-clockwise, placing the objective operating mechanism in the observing position.

28. Attach the lower (split) objective lens and mount assembly (Figure 4-22) to the objective operating mechanism assembly (Figure 4-23).

29. Place each assembled mount half on its respective mounting plate (S), and secure each temporarily with two stadimeter collimating screws (13, Figure 4-22) and washers (14). The collimating screws extend through clearance holes in the washers and elongated slots in each mount half (1 and 2) and screw into tapped holes in each mounting plate half (5, Figure 4-23).

4V4. Primary collimation of the upper and lower telescope systems. The upper and lower telescope systems are primarily collimated in the following manner:

1. Assemble the necessary spacer thickness on each V-block face and finder the upper telescope system Parts I and II inner tube section bearings, except the second inner tube section lower end coupling (26, Figure 4-21).

This is necessary to lift the center axis of the upper telescope system in coincidence with the center axis of the lower telescope system coupling bearings which are larger in diameter.

2. Place the lower telescope system assembly described in Section 4V2 in two V-blocks, resting the large bearing flange periphery of the track sleeve (2, Figure 4-23) in one, and the large shoulder flange periphery of the eyepiece skeleton (42, Figure 4-28) and the upper alignment support section periphery of the eyepiece box (11, Figure 4-29) in the other.

3. Rotate the lower telescope system in the two V-blocks for vertical collimation, with the eyepiece end of the eyepiece box facing upward.

4. The special eyepiece alignment jig (Figure 4-50) inserted in Section 4V3, Step 3, remains

5. With the use of a dial indicator attached to a surface gage, determine the parallel position of the outer face of the alignment jig, hence the true vertical position of the emerging light rays in the following manner:

6. The surface gage is used on the surface of the optical I-beam bench (Figure 4-58), with the dial indicator set with sufficient tension on the outer face of the alignment jig.

7. Keep a firm pressure on the base of the surface gage, while checking opposite sides of the outer face of the alignment jig (Figure 4-59).

8. Rotate the lower telescope system on the two V-blocks until both outer faces opposite the

9. Secure the V-block clamps by turning the adjusting knobs of the clamp brackets, as shown on Figure 4-58. Check the face of the alignment jig again to detect any variation and make corrections in the same manner as before.

10. Slide the upper telescope system down on the optical I-beam until it is near the aligned lower telescope system assembly.

11. Line up the reference marks of the second inner tube section lower end coupling (26, Figure 4-21), checking it by the coupling sleeve

(34, Figure 4-23) in its proper coincidence relationship with the track sleeve (2) reference marks.

12. Holding the coupling sleeve (34) on the undercut alignment support sections of the track sleeve (2) and the second inner tube section lower end coupling (26, Figure 4-21), slide the upper telescope system Parts I and II downward snugly against the coupling sleeve. This permits the coupling sleeve to fit snugly between the bearing shoulders of the track sleeve (2, Figure 4-23) and the second inner tube section lower end coupling (26 Figure 4-21). Remove the coupling sleeve and place it in a convenient place until it is required again for distance measurement or for reassembly.

13. Remove the eyepiece alignment jig (Figure 4-50) and replace the assembled eyepiece lens mount (19, Figure 4-28) by screwing it into the eyepiece prism front retaining plate

14. Remove the four lockscrews (12, Figure 4-20) from the upper part of the reducing coupling (2), unscrewing them from the tapped holes in the lower alignment support section of the first reduced tube section (1).

15. Unscrew the first reduced tube section (1) from the internal upper part of the reducing coupling (2).

16. Screw the temporary mechanical crosswire adapter (Figure 4-56) into the threaded counterbored section in the lower part of the first reduced tube section (1, Figure 4-20).

17. Replace the first reduced tube section (1), screwing its lower threaded periphery into the internal threaded upper section in the reducing coupling (2). The lower part of the temporary

Figure 4-58. Dial indicator determination of true vertical position on the left side face of the eyepiece alignment jig.

18. The purpose of the temporary mechanical crosswise adapter (Figure 4-56) is to establish a target on which the upper objective lens is focused; it also provides a reference point from which the correct position of the collective lens (21, Figure 4-20) is found.

19. The collective lens (21) is located 52 mm from the focal plane toward the upper eyepiece lens (20). This distance establishes the proper lens separation of 394 mm between the upper eyepiece lens and the collective lens and results in the correct EFL of this eyepiece combination.

20. The EFL of the upper eyepiece lens must be 432 mm to have the correct image size so that

Figure 4-59. Dial indicator determination of true vertical position on the right side face of the eyepiece alignment jig.

21. The EFL of the upper eyepiece lens (20, Figure 4-20) in the Type II is changed from 451 mm to 432 mm by the proper spacing of the collective lens (21). The equivalent focal length is found by using the following formula:

(F₁ X F₂) / (F₁ + F₂ - S) = EFL

F₁ = 451 mm
F₂ = 1326 mm
S = 394 mm

(451 X 1326) / (451 + 1326 - 394) = 432.3 mm

22. The primary collimation of the lower telescope system is accomplished by the axial movement of the upper objective lens and its mount (41, 42, and 38). This brings the eyepiece prism mount arrangement of the eyepiece skeleton assembly (4-28) into focus with the temporary crosswise adapter (Figure 4-56) to obtain the minus and plus diopter settings.

23. In checking the essential travel of the eyepiece prism mount (20, Figure 4-28) which should be 25 mm, diopter lenses are used. Minus and plus lenses must be inserted in the auxiliary telescope adapter to obtain the minus and plus diopter settings. This adapter is attached to the objective end of the auxiliary telescope.

24. Insert a -1 1/2 diopter lens in the auxiliary telescope adapter (Figure 4-57), moving the counterweight up to its stop for full travel; the stop is the spider bearing (3, Figure 4-27). This causes the eyepiece prism mount to move downward. Check the definition of the temporary crossline adapter to be sure that it fades slightly at the end of eyepiece prism travel. It is necessary to move the upper objective lens mount (38) and the lens (41 and 42, Figure 4-20) axially to make this definition check.

25. Insert the +3 diopter lens in the auxiliary telescope adapter (Figure 4-57), and bring the counterweight downward to the lower stop, the two lockscrews opposite each other in the eyepiece skeleton flange (42, Figure 4-28). These lockscrew heads are longer than the other six lockscrews in the eyepiece skeleton flange.

26. Continue the procedure outlined in steps 24 and 25 until a slight overtravel is observed at -3 and +1 1/2 diopters.

27. Upon completion of the collimation of the lower telescope system, secure the upper objective lens mount (38) in the fifth inner tube section (34) with six lockscrews (36).

28. Now obtain the true zero diopter reading of the diopter ring of the focusing knob assembly (Figure 4-39). Using the auxiliary telescope minus the adapter (Figure 4-57), focus the eyepiece prism mount until sharp definition of the temporary crosswire adapter is noted. The diopter ring (9, Figure 4-39) should read -3/4 diopter at atmospheric pressure. This allowance is compensated for when nitrogen of 7 1/2 psi is introduced. Refer to Section 4V7.

29. Unscrew the first reduced tube section (1, Figure 4-20) from the reducing coupling (2). Remove the temporary crosswire adapter (Figure 4-56), unscrewing it from the lower part of the first reduced tube section.

30. Screw the diaphragm (13, Figure 4-20) into the lower internal threads, of the first reduced tube section (1) until its lockscrew hole coincides with the tapped hole in the alignment support section tapped hole in the first reduced tube section.

31. Insert and secure the lockscrew (7). The lockscrew is inserted into a countersunk clearance hole in the lower alignment support section of the first reduced tube section (1) and screwed into a tapped hole in the diaphragm, (13).

32. Screw the first reduced tube section lower threaded periphery (1) into the internal threaded part of the reducing coupling (2).

33. Insert and secure the four lockscrews (12). These lockscrews are inserted in countersunk clearance holes in the reducing coupling (2)

34. Move the upper eyepiece lens mount (6) axially until a clear well-defined image of the collimator reticule or target is apparent. Secure the upper eyepiece lens mount with two lockscrews (10). Do not move the upper eyepiece lens mount (6) in final collimation as this destroys the correct lens separation between the upper eyepiece lens (20) and the collective lens (21).

4V5. Reassembly of the auxiliary upper and lower telescope system assemblies to the upper telescope system assembly. The auxiliary upper and lower telescope systems are reassembled to the upper telescope system assembly in the following manner:

1. Screw the threaded periphery of the lower part of the second reduced tube section (19, Figure 4-19) into the internal threaded section in the first reduced tube section upper part (1, Figure 4-20). Support the attached auxiliary upper telescope system assemblies while making the connection of the auxiliary lower telescope system assembly to the upper telescope system assembly Part I.

2. Secure the first and second reduced tube sections (1 and 19, Figures 4-20 and 4-19 respectively) with four lockscrews (8). These lockscrews are inserted in countersunk clearance holes in the first reduced tube section upper part and screwed into tapped holes in the second reduced tube section lower alignment support section.

3. Place a support under the auxiliary upper telescope system (Figure 4-18). This is necessary because of the weight of the auxiliary upper and lower telescope system assemblies. The support is adjusted until the auxiliary upper telescope system appears in the center axis of the other telescope system assemblies. This is determined by measurement from the surface of the optical I-beam bench and by knowing the measurement previously taken with a special cylindrical disk. The disk diameter should coincide with the diameter of the second tube section lower end coupling (26, Figure 4-21).

4. Assemble the skeleton head assembly to a special adapter (Figure 4-60). The adapter is a

4V6. Final collimation of the four telescope systems in high power. Final collimation of the four telescope systems in high power is accomplished in the following manner:

1. The auxiliary upper and lower telescope systems have been primarily collimated at assembly. This primary step enables the repairman to arrive at the focal distance adjustments in a much shorter time with the assurance that the individual telescope systems have been collimated.

2. Final collimation consists of coordinating the various telescope systems into a telescope combination; this requires minor fine adjustments.

3. Place an auxiliary telescope at the eyepiece end and set the periscope for -3/4, diopter at atmospheric pressure.

4. Check the series of telescope systems on the telemeter lens for clear definition. If necessary, move the auxiliary lower eyepiece lens mount (13, Figure 4-19) axially to improve the definition on the telemeter lens.

6. Secure the auxiliary lower eyepiece lens mount (13) with two lockscrews (17). These lockscrews are inserted into countersunk clearance holes in the third reduced tube section (12) and screwed into tapped holes in the mount.

7. Replacement of parts of the mechanical or optical system necessitates a change in the screw hole alignment. If no mechanical or optical parts have been required during overhaul, little difficulty should be experienced in arriving at the original screw alignment of the manufacturer.

8. Temporary squaring of the telemeter lens is required for the collimation of the lower (split) objective lens with the Kollmorgen universal collimator range reticle and the telemeter lens.

9. Displace the lower (split) objective lens to the maximum displacement of the range position. In this maximum displacement, the telemeter lens line should be apparent to the observer as a solid line. If this vertical line appears double or faded, it is necessary to rotate the telemeter lens mount. Continue until the telemeter lens line appears as a solid line.

In the ordinary sense the term collimator implies that a target is placed in the focal plane of an objective lens so that an image is formed at infinity. This image, then, acts as an infinitely distant object for the periscopic system that is to be collimated.

The collimation of a periscope is complicated, however, by the fact that the highly important separations between the various lenses are established with the lenses surrounded by air at normal atmospheric pressure, whereas in actual use the lenses are surrounded by nitrogen at about 22.2 psi (absolute) pressure (atmospheric pressure plus 7.5 psi). The introduction of this denser gas causes a relative decrease in the index of refraction of the glass, effecting a decrease in the refracting power of each lens and an increase in the focal length of each lens in the periscope.

If we understand that periscope collimation means farming on the telemeter an image of an infinitely distant object without parallax, we may consider the effect of this denser gas on a) all the lenses following the telemeter lens and b) all the lenses preceding the telemeter lens. It has been computed that the increase in focal length of all lenses following the telemeter lens can be compensated after gassing by moving the eyepiece lens 3/4 diopter in a plus direction. It is only necessary before collimating in air to set the eyepiece at minus 3/4 diopter. After the periscope is gassed and the eyepiece lens is moved to the zero diopter setting, all change in

The lenses preceding the telemeter lens, however, cannot be precompensated so easily, and the problem may be approached in the following manner: In the Type II periscope (in high power) there is only one lens preceding the telemeter lens, that is, the auxiliary upper eyepiece lens with an equivalent focal length of plus 168.1 mm in air. Figure 4-61 shows the auxiliary upper eyepiece lens focused on an infinity target in air. The focal length of this same lens in nitrogen at 7.5 psi above atmospheric pressure is lengthened to plus 168.177 mm, or an increase of 0.077 mm. This is the same as saying that the focal length of the lens in dense nitrogen is 1.00046 times that in air. In order to adjust the lens in air so that there is no parallax caused by the dense gas, a target distance, which is less than infinity and causes the image to be formed 0.077 mm farther from the lens, exactly in the plane which becomes the back focal plane when the lens is surrounded by the nitrogen, should be chosen. This distance is found to be 1,200 feet.

The method of determining the conjugate object-distance is calculated as follows:

The equivalent focal length (EFL) of the image-forming lens or auxiliary upper eyepiece lens (Type II, high power) taken from the optical detail drawing equals 168.1 mm. The increase in EFL caused by gas pressure is found by multiplying the 168.1 mm by 1.00046 and then subtracting 168.1 mm from the result. A shorter method is to multiply the 168.1 by 0.00046 and find the increase directly.

Desired object-distance = (168.1)
X (168.1) = increase in EFL

or in the present example:

Object distance =
((168.1) X (168.1) / 0.077) =
28258 / 0.077 =
366,987 mm

Next, 366,987 mm is converted to feet by dividing by 304.8 mm (the number of mm in one foot). Thus, the desired object distance equals 1,204 feet, or as stated above, 1,200 feet.

Summary: If the distance between the auxiliary upper eyepiece lens and the telemeter lens is adjusted so that a target 1,200 feet distant is imaged exactly in the plane of the telemeter lens when the lens is surrounded by air, when the lens is surrounded by nitrogen at the above

What has actually been done, then, while the auxiliary upper eyepiece lens is still surrounded by air, is to shift the back focal point of that lens exactly 0.077 mm (= 0.003 in.) upward. Since the telemeter lens is 2.75 mm thick (= 0.110 in.), it is apparent that the back focal point of the auxiliary upper eyepiece in air will lie approximately 0.107 inch behind the curved surface and 0.003 inch ahead of the plane surface of the telemeter lens, that is, inside the lens itself. Figure 4-62 shows the ray diagram of this action.

With the distance between the two lenses thus adjusted in air, the introduction of nitrogen at plus 7.5 psi lengthens the equivalent focal length of the auxiliary upper eyepiece lens exactly enough to cause its back focal point

Obviously, this adjustment should not be made by moving the telemeter lens (for there already has been made a 3/4 diopter adjustment of the periscope eyepiece lens which is based on maintaining a fixed position of the telemeter lens, to compensate for the effect of the denser nitrogen on focal lengths of lenses following the telemeter); therefore, the only possible adjustment is to move the auxiliary upper eyepiece. Since the manufacturers of the periscope are aware of these facts, they have designed the instrument so that only the ninth reduced tube section (which carries the auxiliary (upper eyepiece lens) is capable of adjustment.

It might be possible to move the auxiliary upper eyepiece, 0.003 inch away from the telemeter lens; however, since this distance is small, it is much more accurate to measure this distance optically (that is, by using a target or object-distance at 1,200 feet) than to measure it mechanically.

4V8. Basic principles of the Kollmorgen universal collimator. The basic principles of the Kollmorgen universal collimator are described as follows:

Since the introduction of nitrogen under pressure necessitates collimating the periscope on targets that are not at infinity, when the lenses are in air (see target table under the first function), and since targets at 4,800 feet, 3,110 feet, and even 1,200 feet are not possible aboard a repair tender, the distance collimator is used to reproduce these object-distances optically.

If the target is placed less than one focal length away from the collimator objective, the ray bundles diverging from each point of the target have more divergence than the converging lens is able to neutralize, and the ray bundles emerging from the collimator lens are still diverging slightly. For example, if the equivalent focal length of the objective of the collimator equals 481.7 mm = 19.27 in. and if the target is moved 0.025 inch from the focal plane toward the objective, a virtual image is formed at a distance of 1,200 feet from the collimator lens and on the same side of the lens as the target (Figure 4-65). Thus, the rays from each point of the target, after emerging from the collimator lens, are still diverging at exactly the same rate as though they had originated at a real target 1,200 feet distant.

Taking another example, it is desired to adjust the distance between target and collimator objective so that the virtual image lies 35 feet in front of the collimator lens (on the same side as the target). If the collimator objective lens has the same focal length as in the preceding example, and if the target is moved 0.819 inch from the focal plane toward the objective, the image is virtual and is 35 feet from the collimator objective, as indicated in Figure 4-66.

Thus it is seen that by suitably controlling the distance between the target and the collimator

This, however, is only one of the three main functions of the Kollmorgen universal collimator. The three functions are as follows:

1. It is an optical means of producing distant targets in a limited space for shipboard use, as outlined above. The distances that are necessary for the different types of periscopes (to compensate for the introduction of nitrogen under pressure) are:

If the collimator objective lens has an equivalent focal length of 481.7 mm (= 19.268 in.), in order to place the virtual target at the desired distances listed in the foregoing table, it is necessary to move the actual target from the focal plane of the collimator objective toward the objective lens by the amounts shown in the table on page 237.

It must be remembered that the figures in this table apply only when the collimator objective lens has an equivalent focal length

equal to the above value. Since the factory tolerance of lenses for this collimator is held to plus or minus 1 percent of the specified focal length, no sensible variation results.

2. The Universal collimator is an optical means for checking accurate displacement of the lower (split) objective lens halves with calibrated range dials of the stadimeter at a known height on a graduated reticle lens set at infinity.

It consists of a graduated reticle lens used with a collimator objective lens of effective focal length of exactly 481.7 mm (Figure 4-67). The reticle lens (Figure 4-68) is provided with etched vertical and horizontal lines forming a crossline. The lower right quarter of the reticle has six etched graduated lines, each line being of alternate height to distinguish it clearly. The graduated lines are etched on the plano-surface of the reticle, while the curved surface is fine ground. The reticle, being in the focal plane of objective lens, produces parallel light, thereby forming an infinity target.

The reticle lines (Figure 4-68) are spaced consecutively in the following manner: All six graduated lines are located 2.0 mm from the vertical line of the crossline.

a. The first graduated line of 2.5 mm length is located 0.290 nun from the horizontal line of the crossline.

b. The second graduated line of 5.0 mm length is located 0.430 mm from the horizontal line of the crossline.

Figure 4-67. Collimator objective lens, detail drawing.

c. The third graduated line of 2.5 mm length is located 1.285 mm from the horizontal line of the crossline.

d. The fourth graduated line of 5.0 mm length is located 3.210 mm from the horizontal line of the crossline.

e. The fifth graduated line of 2.5 mm length is located 6.425 mm from the horizontal line of the crossline.

f. The sixth graduated line of 5.0 mm length is located 8.030 mm from the horizontal line of the crossline.

The angle formed by the distance between the first graduation and the horizontal line of crossline forms the base relative to effective focal length of objective lens hypotenuse, and is found by dividing:

1) 0.290 mm by 481.7 mm which equals 0.0062 radians or 2 minutes 4 seconds of arc.

2) 0.430/481.7 = 0.00088 radians or 3' 4" of arc

3) 1.285/481.7 = 0.00266 radians or 9' 10" of arc

4) 3.210/481.7 - 0.00666 radians or 22' 55" of arc

5) 6.425/481.7 = 0.01333 radians or 45' 51" of arc

6) 8.030/481.7 = 0.01666 radians or 57' 18" of arc

The above angles correspond to a target angle of 20-foot height at the following ranges:

1) 11,000 yards	4) 1,000 yards
2) 7,500 yards	5) 500 yards
3) 2,500 yards	6) 400 yards

3. As its third function, the Universal collimator provides a means of checking the vertical displacement of the line of sight in changing from high to low power. Two graduations which intersect the vertical line are incorporated in the upper half of the reticle. These provide accurate graduations in degrees for checking this displacement. Both graduations are placed in the reticle as follows:

a. The large graduation intersects the vertical line, and is located 8.410 mm from the horizontal crossline. This distance represents 1 degree of arc in high power or 4 degree in low power. This line extends on each side of the vertical crossline a distance of 7.0 mm.

b. The small graduation intersects the vertical line, and is located 2.100 mm from the horizontal crossline. This distance represents 15' of arc in high power or 1 degree in low power. This line extends on each side of the vertical crossline a distance of 4.5 mm.

4V9. Description of the Sperry-Kollmorgen collimator. The Sperry-Kollmorgen collimator consists of the Sperry attachments which hold the Kollmorgen universal collimator. Figure 4-69 shows the Sperry-Kollmorgen collimator. All bubble numbers in Section 4V9 refer to Figure 4-69 unless otherwise specified.

Ill. No.	Drawing Number	Num- ber Re- quired	Nomenclature
1	P-1641-1	1	Collimator base plate bracket
2	P-1641-2	1	Height adjusting bearing
3	P-1641-3	1	Height adjusting bearing lock ring
4	P-1641-4	2	Collimator base plate shaft lock nut washers
5	P-1641-5	1	Collimator base plate shaft
6	P-1641-6	1	Azimuth disk plate
7	P-1642-1	1	Collimator base plate
8	P-1642-2	2	Collimator base plate shaft, outer lock nuts
9	P-1642-3	1	Collimator base plate shaft, inner lock nut
10	P-1642-4	1	Wedge lock
11	P-1642-5	1	Wedge lock bolt
12	P-1642-6	2	Azimuth disk plate clamp arms
13	P-1642-8	1	Reticle light shield
14	P-1642-10	1	Wing nut stud
15	P-1642-11	2	Azimuth disk plate outer clamp arm washers
16	P-1642-12	1	Azimuth disk plate clamp arm spacer washer
17	P-1642-14	1	Azimuth disk plate clamp arm wing nut
18	P-1642-15	1	Collimator tube bracket height adjusting cap screw
19	P-1642-16	4	Collimator base plate bracket and optical bench bracket cap screws
20	P-1642-17	4	Collimator base plate bracket and optical bench bracket cap screw nuts
21	P-1642-18	2	Reticle light shield lockscrews
22	P-1642-19	2	Filter mount lockscrews
23	P-1642-20	4	Collimator tube bracket cap screw
24	P-1642-20	4	Collimator base plate bracket and optical bench bracket cap screw washers
25	P-1642-21	4	Collimator tube bracket clamp screws
26	P-1642-22	1	Candelabra mazda bulb
27	P-1642-23	1	Keyless socket
28	P-1642-24	1	Brass tubing section
29	P-1642-25	1	Feed-thru cord switch
30	P-1642-26	1	Finger grip plug cap
31	P-1642-27	1	Rubber covered wire cord
32	P-1642-27A	1	Wire cord plug
33	P-1643-1	1	Collimator tube bracket
34	P-1643-2	2	Collimator tube bracket clamps
35	P-1643-3	1	Collimator tube thrust collar
36	P-1644-1	1	Objective lens mount end bushing

Ill. No.	Drawing Number	Num- ber Re- quired	Nomenclature
37	P-1644-2	1	Objective lens mount
38	P-1644-3	1	Objective lens clamp ring
39	P-1644-4	1	Collimator tube
40	P-1644-5	1	Reticle lens mount retaining ring
41	P-1644-6	1	Reticle lens clamp ring
42	P-1644-7	1	Reticle lens mount
43	P-1644-8	1	Reticle lens mount axial alignment key
44	P-1644-9	1	Objective lens mount lockscrew
45	P-1644-10	1	Reticle lens mount alignment key lockscrew
46	P-1644-11	1	Objective lens clamp ring lockscrew
47	P-1644-12	2	Collimator tube and reticle lens mount end bushing also objective lens mount end bushing lockscrews
48	P-1644-13	1	Reticle lens clamp ring lockscrew
49	P-1645-1	1	Filter mount
50	P-1645-2	1	Filter clamp ring
51	P-1645-3	1	Reticle lens mount lock ring
52	P-1645-4	1	Reticle lens mount end bushing
53	P-1645-5	1	Reticle lens mount actuating sleeve
54	P-1645-6	1	Name plate
55	P-1645-7	2	Name plate lockscrews
56	P-1645-8	6	Reticle lens mount retaining ring lockscrews
57	P-1645-9	1	Micrometer vernier arm
58	P-1645-9A	4	Micrometer vernier, arm lockscrews
59	P-1646-1	1	Objective lens
60	P-1646-2	1	Reticle lens
61	P-1646-3	1	Filter, Corning sextant green

a. Collimator base plate bracket. The collimator base plate bracket (1) is made of cast bronze. It has a large rectangular base flange with two supporting webs below the base flange. The base flange is attached to a welded plate at the end of the optical I-beam bench with four cap screws (19), washers (24), and nuts (20). The four holes in the base flange are elongated, thus allowing for the adjustment of the bracket during the alignment of the Sperry-Kollmorgen collimator to the optical I-beam bench.

The rectangular base flange has a projecting arm, which has a 45 degrees inclination. The width

The wall thickness of the projecting arm is uniform, except for a supporting web in the center extending upward to the hub section from the base flange, located on the outer side following the pattern of projecting arm inclination. The hub section extends outward 1 inch from the outer wall of the projecting arm.

The collimator base plate bracket holds the complete collimator attachment with provision for swinging the collimator base plate (7) through elevation of 95 degrees and depression of 25 degrees as noted by the graduations on the azimuth disk plate (6).

A tapped hole is provided in the wall of the projecting arm at an appropriate center distance below the center axis of the hub section for the azimuth disk plate wing nut stud (14). The stud carries the washer (15) next to the inner projecting arm wall, two azimuth disk plate clamp arms (12) separated with a spacer washer (16), and another washer (15) backed up by the wing nut (17).

b. Height adjusting bearing. The height adjusting bearing (2) is made of brass and is 3 3/16 inches in length. It is cylindrical and is blued. It has a large narrow shoulder flange with an undercut shoulder a sliding fit in the bore of the collimator base plate bracket (1) projecting arm hub section. Outward from this undercut shoulder section, a thread relief and a threaded periphery to carry a height adjusting bearing lock ring (3) are provided. A small undercut shoulder section is provided on the outer part of the threaded periphery.

The height adjusting bearing is provided with an offset 1 1/2-inch diameter hole running through

The large hole carrying the collimator base plate shaft (5) permits a variance of eccentricity to the height adjusting bearing, and is secured temporarily with the lock ring (3) upon its

c. Height adjusting bearing lock ring. The height adjusting bearing lock ring (3) is made of 1/4-inch thick brass and is cylindrical. The periphery is medium diamond knurled, with the bore threaded a free turning fit when engaged on the threaded periphery of the height adjusting bearing (2). The lock ring serves to carry the height adjusting bearing (2) snugly against the inner surface of the hub section of the collimator base plate bracket projecting arm (1).

d. Azimuth disk plate. The azimuth disk plate (6) is made of 1/4-inch brass plate having a diameter of 9 inches. The center axis of the plate is bored a sliding fit on the large shoulder flange of the collimator base plate shaft (5). The projecting shoulder of 1/64-inch width allows sufficient free movement of the disk plate when in close contact with the collimator base plate (7) and the shoulder flange face of the height adjusting bearing (2). The projecting shoulder is provided on the inner face and is 3 7/8 inches in diameter.

The inner face of the plate is graduated in degrees covering 120 degrees. Each degree marking between the interval of 5 degrees is 3/16 inch in length, starting on a diameter of 8 inches. Every fifth degree interval is 1/4 inch in length. Starting with the sixth interval from the right, the 0 numeral is engraved. Each 10-degree interval is engraved additive to and including the 90 degrees for elevation. The same pattern is followed for the 10-degree intervals in depression.

The azimuth disk plate is secured with the two azimuth disk plate clamp arms (12). Each arm has a piece of green beige glued to its inner contact face, which secures the plate by the tightening of the wing nut (17).

e. Collimator base plate shaft. The collimator base plate shaft (5) is made of plain carbon

The square shoulder section carries the square broached hole in the collimator base plate. (7). The square shoulder section has an undercut shoulder on its outer face to carry a lock nut washer (4). The small undercut stub section has the periphery threaded to carry the hexagon lock nut (9) to secure the collimator base plate (7) tight against the large shoulder flange section.

The thickness of the large narrow shoulder flange is sufficient to allow the azimuth disk plate (6) a snug sliding clearance between the attached collimator base plate (7) rear face and the face of the large shoulder flange of the height adjusting bearing (2).

The main body section is a sliding fit in the large offset hole in the height adjusting bearing (2), and retains the collimator base plate (7) at the desired degree of azimuth by means of a wedge lock (10) clamped snugly by the wedge lock bolt (11). The outer part is provided with a threaded periphery to carry a locknut washer (4) and two hexagon locknuts (8). The washer rests against the outer face of the height adjusting bearing (2) and the shaft is secured by the two hexagon locknuts (8).

f. Wedge lock and wedge lock bolt. 1. Wedge lock. The wedge lock (10) is made of plain carbon steel and is 2 1/8 inches in length. The outside diameter is a sliding fit in the eccentric counterbored section in the narrow shoulder section hole in the height adjusting bearing (2). It has a concave radius located 1 1/2 inches from the solid end face. The concave radius conforms to the contour of the collimator base plate shaft main body (5).

The center axis has a tapped hole to receive the threaded section of the wedge lock bolt (11). The tightening of the wedge lock bolt shoulder against the spot face in the height adjusting bearing narrow shoulder (2) causes the concave radius to secure the main body of the collimator base plate shaft (5), thus maintaining the collimator base plate (7) in the desired azimuth setting.

g. Azimuth disk plate clamp arms. The two azimuth disk plate clamp arms (12) are made of 1/8-inch brass and are 3 inches in length. Both are provided with elongated slots to allow them to slide axially away from the azimuth disk plate (6). The inner face of each pointed clamp arm is provided with a piece of glued green beige for clamping of the azimuth disk plate (6) and the prevention of scratches to it while clamping. The clamp arms are carried on the projecting wing nut stud (14). The inner clamp arm rests against a washer (15) and is separated from the outer clamp arm with a spacer washer (16). The securement of both arms is accomplished by the tightening of a wing nut (17) on the outer washer (15).

h. Collimator base plate. The collimator base plate (7) is made of 3/8-inch steel plate and is 35 inches in length. The axial section is provided with a square broached hole, a sliding fit over the square section shoulder of the collimator base plate shaft (5), and is secured to it by the locknut washer (4) and locknut (9).

The axial section is 8 inches in diameter and forms a concave junction on opposite sides of the centerline with the arm 4 5/8 inches wide. The arm is uniform in width from the concave junctions in a distance of 21 1/4 inches. Beyond this point the arm forms a concave junction on opposite sides with a handle 1 1/2 inches in width and 6 3/4 inches in length.

The axial section is beveled at 30 degrees covering a 60 degree minor chord area with an engraved line intersecting its centerline. The engraved line serves as an index line to designate the position of the collimator in azimuth when in coincidence with the graduations of the azimuth disk plate (6).

The outer 1-inch part of the handle section is undercut to carry the reticle light shield (13) secured on opposite side with two lockscrews (21). A 1/8-inch pipe tapped hole is provided near the end of the handle to receive a brass tubing section (28). It carries the keyless socket (27), and a candelabra mazda bulb (26).

i. Collimator tube bracket, thrust collar, and tube. 1. Collimator tube bracket. The collimator tube bracket (33) is made of cast bronze and is rectangular shaped. Its width conforms to the width of the collimator base plate (7) arm section, and the length is sufficient to carry the collimator tube (39).

The base of the bracket is provided with a 1 1/2-inch raised boss section on each end the entire width, with a cored section connecting the raised boss sections. These sections are secured to the arm section of the collimator base plate (7) with four cap screws (23) which are inserted into clearance holes in the base plate and screwed into tapped holes in the raised boss sections to secure the bracket to the base plate.

The bracket is provided with end walls which are reinforced with 45 degrees angle webs from the main body, and has a center web connecting each end wall. A semicircular clamp (34) is fitted on each end wall upper lace and secured with two Allen head cap screws (25) each. The cap screws are inserted into clearance holes in the clamps (34) and screwed into tapped holes in the end walls. The end walls and the clamps are bored together, to carry the collimator tube (39)

A rectangular name plate (54) is secured to the main body with two lockscrews (55).

2. Collimator tube thrust collar. The collimator tube thrust collar (35) is made of brass and is cylindrical. It has an outside

3. Collimator tube. The collimator tube (39) is made of brass and is 15 inches in length. The external surface is uniform its entire length with the bore having a nominal wall thickness. The bore is provided with blued anti-reflection threads.

The opposite ends of the tube are provided with threaded counterbored sections of equal depth. One end carries the threaded periphery section of the objective lens mount end bushing (36) secured with a lockscrew (47), while the opposite end carries the threaded periphery section of the reticle lens mount end bushing (52) secured with a lockscrew (47).

j. Objective lens mount end bushing, lens mount, lens, and clamp ring. 1. Objective lens mount end bushing. The objective lens mount end bushing (36) is made of brass and is 3 inches in length. The large external diameter conforms to the diameter of the collimator tube (39). The undercut section is threaded to engage in the threaded counterbored section in the collimator tube and is secured with a lockscrew (47).

The inner surface is bored for light transmission and threaded for anti-reflection. Its outer part is counterbored and threaded a sufficient depth to carry the threaded periphery objective lens mount (37). The threaded counterbored section is of sufficient depth to allow axial movement of the objective lens mount (37) for collimation of the collimator. The mount is secured with a lockscrew (44) after collimation. This lockscrew is screwed into a tapped hole in the objective lens mount end bushing wall (36) and extends into the spotted face in the threaded periphery of the mount.

2. Objective lens mount. The objective lens mount (37) is made of brass and is 3/4 inch in length. The periphery is threaded and screws

3. Objective lens. The objective lens (59) is made of two optical elements, consisting of a double convex crown element cemented to a divergent meniscus flint element, forming a positive doublet. It is mounted in the objective lens mount (37) with the crown element resting against the seat of the mount. It is secured snugly with a clamp ring (38) and a lockscrew (46, Figure 4-67 shows this lens in detail).

4. Objective lens clamp ring. The objective lens clamp ring (38) is made of brass and is of nominal thickness and width. The periphery is threaded to screw into the threaded counterbored section in the objective lens mount (37) to secure the objective lens (59). The clamp ring is chamfered at 15 degrees from its bore, and is provided with opposite slots in the narrow side face for the insertion of a special wrench. The clamp ring As secured with a lockscrew (46) which extends inward from a tapped hole in the objective lens mount (37) into the partially tapped hole in the clamp ring.

k. Reticle lens mount end bushing, mount, lens, and clamp ring. 1. Reticle lens mount end bushing. The reticle lens mount end bushing (52) is made of brass and is 4 13/16 inches in length. The external surface is provided with a large shoulder section of 1 1/2 inches to accommodate sufficient wall thickness for the internal counterbored section. The medium shoulder section diameter conforms to the diameter of the collimator tube (39), while the small undercut shoulder is threaded to engage into the outer end of the collimator tube threaded counterbored section, and is

The end bushing is bored for light transmission and is threaded for anti-reflection. It is provided with two counterbored sections; the smaller of the two has a depth of 3.875 inches and carries the reticle lens mount (42) of an axial sliding fit. The large counterbored section is threaded and has sufficient depth to accommodate the axial movement of the reticle lens mount actuating sleeve threaded periphery (53).

The medium shoulder is provided with an axial slot in a 1 1/16-inch distance. The axial slot serves as a guide for the axial alignment key (43) attached to the reticle lens mount (42). The periphery of the medium shoulder section is engraved at intervals for the various target distances of the present three types of periscopes used in the submarine service, starting from the infinity engraved graduation. These graduations are determined after assembly by calculation and known target distances. The engraved index line on the axial alignment key (43) designates the position of the reticle lens (60).

A micrometer vernier arm (57) is secured on the large shoulder periphery with four lockscews (58) and furnishes the repairman an accurate determination as to the calculated distance the reticle lens mount is moved inward axially for each distance determination.

2. Reticle lens mount. The reticle lens. mount (42) is made of brass and is 4 9/16 inches in length. It is cylindrical, and is provided with a narrow shoulder flange in the outer part. The external diameter is a sliding fit in the small counterbored section in the reticle lens mount end bushing (52) and is carried axially by the reticle lens mount actuating sleeve (53) with its attached axial alignment key (43).

The external diameter is undercut a distance of 2.125 inches to its narrow shoulder flange, thus allowing a nominal bearing surface for the reticle lens mount actuating sleeve (53). The narrow shoulder flange fits into the counterbored section in the reticle lens mount actuating sleeve, and is carried outward axially by means

The mount is bored for light transmission and is threaded for anti-reflection. The inner end has two counterbored sections. The smaller serves as a seat for the reticle lens (60), while the larger is threaded to carry the clamp ring (41) snugly against the reticle lens, and is secured with a lockscrew (48).

3. Reticle lens. The reticle lens (60) is a plano-convex crown element. The convex surface is fine round, and faces the seat of the reticle lens mount (42). It is secured snugly in the seat of the mount with the clamp ring (41) secured with a lockscrew (48). The plano surface of the lens is engraved, and is described under Section 4V8 and 2nd function. Figure 4-68 shows the detailed calibrations of this lens.

4. Reticle lens clamp ring. The reticle lens clamp ring (41) is made of brass and is of nominal thickness and width. The periphery is threaded to screw into the threaded counterbored section in the reticle lens mount (42) to secure the lens. It is bored for light transmission, and has a counterbored section threaded for anti-reflection. The counterbored section leaves a narrow flat shoulder to contact the plano-surface of the reticle lens (60). The narrow side face is provided with two opposite slots for the insertion of a special wrench. The clamp ring tightens the reticle lens snugly and is secured with a lockscrew (48). The lockscrew is screwed into a tapped hole in the reticle lens mount (42) and extends into a partially tapped hole in the clamp ring.

1. Reticle lens mount axial alignment key. The reticle lens mount axial alignment key (43) is made of corrosion-resisting steel and is 0.406 inch in length. It is a sliding fit in the axial slot in the reticle lens mount end bushing (52) and is secured to the reticle lens mount bearing shoulder periphery in the axial slot with a lockscrew (45). The lockscrew is inserted into a countersunk clearance hole located 1/8 inch from its end, and is screwed into a tapped hole in the mount. Both ends of the key have a convex radius to conform to the concave radius ends of the axial slot. An

m. Reticle lens mount actuating sleeve. The reticle lens mount actuating sleeve (53) is made of brass and is 1 15/16 inches in length. It is provided with a large shoulder flange, having its periphery medium diamond knurled. The undercut section is threaded its entire length with 32 threads per inch to carry a lock ring (51) and engages into the threaded counterbored section in the reticle lens mount end bushing (52). It is bored to carry the reticle lens mount (42), a sliding fit with a counterbored section in its large shoulder flange. This counterbored section serves as a thrust stop to carry the reticle lens mount (42) axially in the reticle lens mount end bushing (52). The outer face of the large shoulder flange is provided with a retaining ring (40) secured with six lockscrews (56). This retaining ring serves as a thrust ring to carry the reticle lens mount (42) axially into the reticle lens mount end bushing (52). The six lockscrews (56) are inserted in countersunk

Figure 4-70. Collimator micrometer vernier arm.

n. Reticle lens mount lock ring and retaining ring. 1. Reticle lens mount lock ring. The reticle lens mount lock ring (51) is made of brass and is of nominal thickness and width. Its periphery conforms to the periphery of the reticle lens mount actuating sleeve (53) large shoulder flange, and is knurled in the same manner. The bore is threaded and screws on the actuating sleeve threaded periphery. The lock ring, when screwed up against the shoulder of the reticle lens mount end bushing (52), secures the actuating sleeve from further movement, thus locking it in place.

2. Reticle lens mount retaining ring. The reticle lens mount retaining ring (40) is made of 1/16-inch brass. It is cylindrical, with the outer and inner diameter conforming to the large shoulder flange inner and outer diameters. The retaining ring is provided with six equally spaced countersunk holes for lockscrews (56). The lockscrews are inserted into the countersunk clearance holes in the retaining ring and screwed in tapped holes in the large shoulder flange of the reticle lens mount actuating sleeve (53). The retaining ring serves as a thrust ring to carry the reticle lens mount (42) axially into the reticle lens mount end bushing (52) with the movement of the actuating sleeve (53).

o. Micrometer vernier arm. The micrometer vernier arm (57) is made of brass and is 3 inches in length. It has a rectangular base section with a narrow vernier arm section. The inner circumference of the rectangular base section follows the contour of the reticle lens mount end bushing large periphery and has a nominal wall thickness. Figure 4-70 shows an enlargement of this vernier arm for fleet adaptation.

The inner circumference of the narrow vernier arm section is stepped upward with a chamfer allowing clearance over the periphery of the lock ring (51) and the shoulder flange of the reticle lens mount actuating sleeve (53). The vernier arm is beveled at approximately 20 degrees, and is engraved in 1/32-inch intervals, having a total

Each revolution of the reticle lens mount actuating sleeve (53) represents 1/32-inch axial movement of the reticle lens (60) and mount (42). The knurled periphery of the reticle lens actuating sleeve shoulder flange is undercut a distance of 9/64 inch from the inner shoulder face. This provides a smooth surface for the engraving of micrometer graduations and numerals. This undercut periphery has 31 equal graduations which represent a fraction over one-thousandth inch between each graduation. Starting with 0 as the infinity numeral, every fifth graduation is additive by 5 for each additional numeral up to and including 30. The 31 graduations on the undercut periphery represent 0.03125 thousandths inch or 1/32 inch upon one complete revolution of the reticle lens mount actuating sleeve shoulder face from the 0 graduation until it again reads 0 next to the vernier arm. The vernier graduations designate the number of turns or 1/32 inch the reticle lens (60) and mount (42) are moved, axially from the 0, or infinity, setting of the Kollmorgen universal collimator. The lock ring (51) is secured each time snugly against the face of the reticle lens mount actuating sleeve (53). The securement of the lock ring starting at infinity removes the lost motion in the threads, and places an outward thrust on the reticle lens mount actuating sleeve at each locked setting.

The vernier arm rectangular base is secured to the reticle lens mount end bushing (52) periphery perpendicular to the axial slot on the light side. The four tapped holes are spotted from the clearance holes in the rectangular base after the Kollmorgen universal collimator is collimated at infinity by using a Quartermaster glass of 16-power or a transit of 24-power magnification set for sharp definition. The lock ring (51) is

Secure the micrometer vernier arm to the periphery of the reticle lens mount end bushing (52) with four lockscrews (58). These lockscrews are inserted in countersunk clearance holes in the rectangular base and screwed into tapped holes in the reticle lens mount end bushing (52).

p. Reticle light shield. The reticle light shield (13) is made of brass tubing and is 5 inches in length. The lower part of the shield has two opposite 1/2-inch wide lugs for attachment to the outer handle section of the collimator base plate (7) and is secured with two lockscrews (21). The upper end of the shield has a soldered cap to confine the illuminated light rays to the perpendicular exit of the shield.

The shield setting on the side face of the collimator base plate (7) has a short piece of brass tubing soldered to it, forming a spud joint. Two screws (22) are located on opposite sides of this junction section projecting inward to carry the filter mount (49). The shield covers the candelabra mazda bulb (26) screwed in the keyless socket (27).

q. Filter mount. The filter mount (49) is made of brass and is 25/32 inch in length. It consists of a large narrow shoulder and an undercut medium shoulder. The long undercut shoulder of 1/2-inch length is a sliding fit with the junction brass tubing section of the reticle light shield (13) and engages with the two opposite projecting screws (22).

The mount is bored for filtered light illumination, and is counterbored to carry the filter (61) of Corning sextant green. The outer part of the counterbored section is threaded to carry the filter clamp ring (50).

The narrow undercut shoulder carries a cylindrical disk 1/16 inch wide and 3 17/32 inches in diameter, which is soldered to the narrow shoulder. The large diameter of the cylindrical disk serves as a shield to prevent stray light other than the illuminated light from illuminating the reticle lens (60).

The long undercut shoulder section is provided with two bayonet slots to secure the mount in the shield junction upon their engagement with the inward projecting screws (22).

The feed-thru cord switch is an a.c. or d.c. switch having an OFF and ON switch lever.

s. Collimation. 1. The Kollmorgen universal collimator is collimated at infinity with the reticle lens mount axial alignment key (43) near the outer end of the axial slot of the reticle lens mount end bushing (52). The transit is focused on an infinity distant target of 2,000 yards or better, free of any detection of parallax. The transit is transported with this setting for adjustment of the collimator at the transit infinity setting. Remove the lockscrew (44) and turn the objective lens mount axially until observations indicate that no parallax is apparent on the reticle lens crossline. Insert and secure the lockscrew (44) after collimation, placing a new spotted face in the objective lens mount threaded periphery (37).

2. A suitable method to be followed on a repair tender is to place a Quartermaster glass of 16-power magnification (with the eyepiece set at 0 diopter), followed with a 3-power magnification auxiliary telescope (with the eyepiece set for the observer's eye) to check the collimator infinity setting.

The auxiliary telescope is focused from plus diopter to the observer's diopter reading, to ascertain that the reticle crossline and diopter readings are in sharp definition. At this reading there should be no parallax apparent on the reticle lens crossline. A series of observations to determine the correct setting of the objective lens (59) should be taken.

All ranges in feet below the infinity target are calculated in thousandths-inch as per actual target movement table. Refer to Section 4V8, first function.

The Quartermaster glass used should be in collimation.

4V10. Alignment of the Sperry-Kollmorgen collimator to the optical I-beam bench. This procedure

a. General. The Sperry-Kollmorgen collimator is swung through azimuth for checking the elevation and depression angles of the head prism. Since the altiscope mechanism elevates and depresses the line of sight of the periscope without change in azimuth of more than 10 minutes of arc, between an elevation of 10 degrees and depression of 10 degrees of the line of sight, it must be properly aligned to the perpendicular and horizontal plane of the optical I-beam bench. Check the reticle lens mount actuating sleeve (53) to ascertain that its 0 micrometer graduation is located at the 0 graduation as indicated by the micrometer vernier arm (57, Figure 4-71).

It is used with the periscope lying in a horizontal plane in V-blocks on the optical I-beam bench having a true parallel plane. The observer views the collimator reticle lens looking downward into the eyepiece end of the periscope. The Sperry-Kollmorgen collimator used travels in a vertical plane.

b. Alignment. The Sperry-Kollmorgen collimator is aligned to the optical I-beam bench in the following manner:

1. Place the boresight disk of 6.495-inch diameter in the V-block of the optical I-beam bench (Figure 4-72). Secure the boresight disk by turning the adjusting knobs of the V-block attached clamp bracket. These clamp the disk tight in the V-blocks.

2. Insert the boresight telescope, screwing the threaded periphery into the internal threaded axis of the boresight disk. The telescope adjusting screws are to be set truly horizontal and vertical. Tighten the knurled lock ring of the boresight telescope against the disk (Figure 4-72).

3. Place the crossline disk of 6.495-inch diameter in the V-block located at the far end and on the optical I-beam bench.

4. Focus the telescope on the grooved-crossline disk until the crossline of the telescope is observed sharply. Center the crossline inter section on the hole of the grooved disk by means

Figure 4-71. Infinity setting of collimator.

of the telescope adjusting screws. Rotate the grooved crossline disk through 360 degrees. At the same time, observe whether the crossline intersection remains on the distant test point. If the crossline intersection does not shift, the telescope is in collimation.

5. Remove the grooved crossline disk from the V-block. Swing the collimator base plate (7) to a horizontal position, locking it by means of the wedge lock bolt (11, Figure 4-73).

Figure 4-72. Boresight telescope attached in boresight disk and secured in V-block with clamp bracket; crossline disk in V-block at far end of the optical I-beam bench.

7. Release the wing nut (17), holding the azimuth disk plate arms (12). Rotate the azimuth disk plate (6) so that the 90 degrees numeral graduated line is in coincidence with the index line on the beveled 60 degrees minor chord of the axial section of the collimator base plate (7).

8. Secure the wing nut (17) and azimuth disk plate arms (12) after proper setting of the azimuth disk plate (6).

9. Place the checking telescope trunnion bracket on the far end of the optical I-beam

Figure 4-73. Collimator secured in a horizontal position.

Figure 4-75. Collimator in a horizontal position facing toward the boresight telescope for alignment with optical I-beam bench.

Figure 4-77. Alignment of the collimator using the Mark 1 checking telescope attached in the trunnion bracket.

10. Place the Mark 1 checking telescope in the trunnion bracket and screw the adjusting screws inward, allowing the adjusting screw segments to contact the checking telescope (Figure 4-76).

11. With the four outer and inner adjusting screws, align the checking telescope crossline to the collimator reticle crossline. When properly superimposed, the checking telescope is swung through azimuth vertically as the collimator base plate is carried through azimuth vertically.

12. The vertical line of the checking telescope crossline is used as a reference to check the vertical line of the collimator reticle crossline that is carried parallel through the azimuth for all degrees of elevation and depression (Figure 4-77). The collimator base plate bracket (1) should be shifted for any irregularity of parallelism, and properly adjusted for squaring of the vertical line of the collimator reticle crossline by the rotation of the collimator tube. This is followed by the adjustment of the Allen head cap screws in opposite sides of the welded plate of the optical I-beam bench.

13. Remove the Mark 1 checking telescope and the trunnion bracket from the optical I-beam bench.

14. These two checking procedures are followed continuously until the collimator reticle lies in a true horizontal plane and is carried through all degrees of azimuth for true vertical plane.

15. Remove the boresight telescope, boresight disk, and the V-block clamping bracket when the two procedures stated in Step 14 are properly corrected.

16. It is necessary to check the height of the inner tube section axis of the Type II and III periscopes using a boresight and grooved crossline disk having a diameter of 6.495 inches, to parallel the axis of the Sperry-Kollmorgen collimator, and the setting of the azimuth disk plate (6) to 90 degrees.

17. It is necessary to have a boresight and grooved crossline disk having a diameter of

18. It is necessary to have a boresight and grooved crossline disk having a diameter of 6.805 inches for the inner tube section offset optical axis of the Type IV periscope, to parallel the axis of the Sperry-Kollmorgen collimator, and the setting of the azimuth disk plate (6) to 90 degrees. However, when the inner tube sections are assembled in the outer tube, the optical axis is offset 0.125 inch higher than the Type II and III periscope optical axis, and requires a boresight and grooved crossline disk having a diameter of 7.618 inches for final checking.

4V11. Collimation of the lower (split) objective lens to the stadimeter dials, using the telemeter lens and the Sperry-Kollmorgen collimator. This procedure is performed in the following manner:

1. Check the stadimeter dials to determine that the observing position of the dials is correct.

2. Check the objective operating mechanism assembly to determine that the lower (split) objective lens and mount assembly are located in the observing position.

3. Place the stadimeter housing assembly at the base of the eyepiece box (11, Figure 4-29). Check the entrance of the female tang coupling (68, Figure 4-24) to ascertain that it engages on the male tang section of the stadimeter transmission shaft (22, Figure 4-27). Insert the four housing bolts (30) in the clearance holes in the stadimeter housing (67, Figure 4-24), screwing the bolts into tapped holes in the eyepiece box base (11, Figure 4-27), securing them snugly.

4. Swing the Sperry-Kollmorgen collimator to the zero line of sight position. Release the wedge lock bolt (11, Figure 4-69) and wedge lock (10) sufficiently to swing the index line on the collimator base plate (7) into coincidence with the 0 numeral graduation on the azimuth disk plate (6).

5. Carry the inner tube sections axially on the optical I-beam bench with the V-blocks until the head prism is spotted centrally over the collimator axis.

6. Place the head prism at zero line of sight, checking the parallel position of its front 90 degrees face in the skeleton head by eyesight, by corresponding its parallelism to the skeleton head frame (Figure 4-78).

7. Unscrew the eyepiece lens mount (19, Figure 4-28), carrying with it the eyepiece lens (52), eyepiece lens clamp ring (16), and its lockscrew (41).

8. Follow the procedure stated in Section 4V4, Steps 1 to 3 inclusive.

9. Slide the lower telescope assembly axially, carrying it with the V-blocks until it is near the lower part of the second inner tube section lower end coupling (26, Figure 4-21).

10. Line up the reference marks of the second inner tube section lower end coupling (26), checking it by the coupling sleeve (34, Figure 4-23) in its proper coincidence relationship with the track sleeve (2) reference marks.

12. Replace the threaded periphery of the special eyepiece alignment jig (Figure 4-50) in the threaded bore of the eyepiece prism front retaining plate (24, Figure 4-28) of the eyepiece skeleton assembly. Screw the jig into this front retaining plate until the shoulder of the jig attains a tight metal to metal contact with the projecting cylindrical shoulder of this retaining plate.

13. Follow the procedure outlined in Section 4V4, Steps 3, 5, 6, 7, 8, and 9 for the alignment of the lower telescope system.

14. Remove the eyepiece alignment jig and replace the assembled eyepiece lens mount (19) by screwing it into the eyepiece prism front retaining plate (24). Check the inner and outer surfaces of the eyepiece lens (52) for cleanliness before replacement.

15. Remove the observing position stop (20, Figure 4-23) from the retaining ring (35) by removing the lockscrews (30). Two factory scribed lines can be seen approximately 27/32 inch apart on the operating gear shoulder (1) and the retaining ring (35). This distance represents 10 degrees on the periphery of the operating gear. When the operating gear is rotated 10 degrees counterclockwise, viewing it from the lower end, the right scribe line on the operating gear coincides with the left scribe line on the retaining ring, and the mounting plates (5) are displaced an amount equal to 2' and 4" of arc.

16. With the operating gear in this position, the range scale dials (50, Figure 4-24) should read 11,000 yards approximately opposite the 20-foot height indication on the height scale dials (52). The collimator reticle should show the horizontal crossline in one image superimposed,

17. If the horizontal crossline of one image shows that the horizontal crossline of the reticle is not superimposed over the first small line of the other image, the sliding half of the lower (split) objective lens and mount assembly (Figure 4-22) which has the elongated holes and recesses parallel to the split of the lens, is moved so that the horizontal crossline of one image is superimposed over the first small horizontal line of the collimator reticle in the other, or the 110/20 graduation. It is necessary to use an offset screwdriver to loosen the stadimeter collimating screws (13) sufficiently to tap the mount lightly with a small rawhide mallet.

18. The stadimeter transmission shaft coupling (14, Figure 4-23) has been previously secured temporarily to the stadimeter transmission shaft (22, Figure 4-27) with two special setscrews inserted for collimation use, with the taper pin holes aligned. Using the offset screwdriver, secure the stadimeter collimating screws (13, Figure 4-22), securing the vertical sliding half of the lower (split) objective lens and mount assembly.

19. Turn the handwheel (12, Figure 4-24) clockwise until the horizontal crossline of the collimator reticle in one image superimposes over the second horizontal graduated line of the collimator reticle in the other image. The range scale dial (50,) should read 7,500 yards approximately opposite the 20-foot height indication value on the height scale dial,(52).

20. Continue turning the handwheel (12) clockwise until the horizontal crossline of the collimator reticle in one image superimposes over the third horizontal graduated line of the collimator reticle in the other image. The range scale dial should read 2,500 yards approximately opposite the 20-foot height indication value on the height scale dial.

21. Continue in like manner with the fourth horizontal line at 1,000 yards approximately opposite the 20-foot height indication value, the fifth horizontal line at 500 yards approximately opposite the 20-foot height indication value, and the sixth horizontal line at 400 yards approximately opposite the 20-foot height value indication.

23. Return the displacement of the lower (split) objective lens images so that the horizontal crossline of the collimator reticle in one image superimposes over the first horizontal graduated line of the collimator reticle in the other image. The range scale dials should read 11,000 yards approximately opposite the 20-foot height indication value on the height scale dial. Check the complete series of ranges, 11,000/20, 7,500/20, 2,500/20, 1,000/20, 500/20, and 400/ 20, noting any error and correcting in the same manner as before.

24. When the range scale dials read correctly, the observation position is determined by turning the handwheel (12, Figure 4-24) counterclockwise slowly until the duplicate images almost close to one image.

25. Replace the observation position stop (20, Figure 4-23) to the retaining ring (35), securing it with two lockscrews (30). Rotate the operating gear (1) and its stop (19) from the observation position stop (20) to the maximum displacement stop (20) with sufficient impact to determine any misalignment which may take place. Check for a double image in the observing position. If one is apparent when the operating ear stop (19) is in contact with the observation position stop (20), it is necessary to manufacture a new observation position stop or build up the present observation position

26. Upon completion of the stadimeter collimation, secure the stadimeter transmission shaft coupling (14) to the stadimeter transmission shaft (22, Figure 4-27) with a taper pin (33, Figure 4-23). It is seldom necessary to redrill and ream a taper pin hole in the coupling and the shaft for a new position of the taper pin (33). Remove the two temporary setscrews from the stadimeter transmission shaft coupling (14).

27. After securing the stadimeter collimating screws (13, Figure 4-22), the parallel moving half of the lower (split) objective lens and mount assembly is secured with two straight dowel pins (15). The dowel pins are also replaced in their original holes in the left mount half and its corresponding mounting plate (5, Figure 4-23).

28. With the optical focus of the instrument at infinity, the etched lines of the telemeter lens should be coincident, or of duplicate height. If it is noted that they are not in correct adjustment, the stadimeter collimating screws (13, Figure 4-22) are loosened sufficiently with an offset screwdriver to tap the perpendicular sliding half of the lower (split) objective lens and mount assembly using a rawhide mallet until the coincident or duplicate height of the etched lines of the telemeter lens are correct. The clockwise rotation of the handwheel (12, Figure 4-24) displaces the lens halves sufficiently to distinguish this adjustment. When corrections have been made, tighten the stadimeter collimating screws (13, Figure 4-22) and insert the two straight dowel pins (15) in their original holes in the same manner as directed under Step 27 of this Section.

29. The range, scale dial (50, Figure 4-24) reading in the observing or single image position should be approximately 2 2/58-foot height indication on the height scale dial (52), as indicated by the numerals stamped on the stadimeter housing (67).

30. After collimation of the lower (split) objective lens and mount assembly (Figure

31. Secure the upper part of the coupling sleeve (34, Figure 4-23) with four lockscrews (22). These lockscrews are inserted in countersunk clearance holes in the coupling sleeve (34) and screwed into tapped holes in the second inner tube section lower end coupling lower alignment support section (26, Figure 4-21).

32. Connect the assembled coupling sleeve (34, Figure 4-23) to the track sleeve (2) of the objective operating mechanism assembly as follows: Take precautions to see that the internal recess in the coupling sleeve is carried over the objective operating mechanism assembly axially in the correct alignment position and that this internal recess is carried over the operating gear pinion (12).

33. The coupling sleeve (34) is carried over the alignment support section of the track sleeve large shoulder flange (2) up against its bearing shoulder. It is secured with 15 lockscrews (27) which are inserted in countersunk clearance holes in the lower part of the coupling sleeve (34) and screwed into tapped holes in the alignment support section of the track sleeve large shoulder flange (2).

34. Check the stadimeter dials and turn the handwheel (12, Figure 4-24) until the dials are at the observing position; the figure 58 on the height scale dial should be approximately opposite the value 2.2 on the range scale dial.

35. Remove the four stadimeter housing bolts (30) from the base of the stadimeter housing (67), removing the stadimeter housing assembly from the base of the eyepiece box (11, Figure 4-29).

36. Overlap system of collimation. A ready means of checking the range scale dials of the stadimeter with the lower (split) objective lens is accomplished by use of the telemeter lens and is called the overlap system. This method is of great importance to a repairman as a rough check of the stadimeter when the periscope is installed in a submarine.

Each large division on the telemeter lens corresponds to an angle of 1 degree at high power, and 4 degrees at low power. Each subdivision corresponds to an angle of 15' at high power and 1 degree at low power.

In high power, the cotangents at these angles are:

Cotangent of 15' = 229.18
Cotangent of 30' = 114.59
Cotangent of 45' = 76.39
Cotangent of 60' or 1 degree = 57.29
Cotangent of 1 degree and 15' = 45.85

When displacing the lower (split) objective lens, and overlapping or superimposing the telemeter lens lines over each other, the range is found as follows:

1. 15 minutes of arc represents a range scale dial reading of 1,500 yards over the 20-foot height scale dial reading.

229.18 X 20 ft = 4,583.60 ft, or 1,527 yd

2. 30' of arc represents a range scale dial reading of 760 yards over the 20-foot height scale dial reading.