1. Part I: First, second, and third inner tube section assembly.

2. Part II: Eyepiece skeleton assembly.

a. " "	Eyepiece box and miscellaneous assemblies.
b. " "	Four packing gland assemblies.
c. " "	Eyepiece window assembly.
d. " "	Bottom plug assembly.
e. " "	Focusing knob assembly.
f. " "	Rayfilter housing, and plate assembly.
g. " "	Rayfilter eye buffer, blinder, and stowage case assemblies.
h. " "	Variable density polaroid filter assembly.

The lower telescope system comprises numerous assemblies end is divided principally to permit familiarization as to nomenclature, description, disassembly, and reassembly. It is composed of two lenses and a dioptric prism, namely: A lower objective lens air-space doublet, and eyepiece prism (dioptric prism), and an eyepiece lens doublet.

7G2. Description of Part I. The first, second, and third inner tube section assembly is shown in Figure 7-10. All bubble numbers in Sections 7G2, 3, and 4, refer to Figure 7-10 unless otherwise specified.

1. Lower objective lens. The lower objective lens (2 and 3) is made of two optical elements. It consists of a double convex crown element separated with a spacer ring (7) from a divergent meniscus flint element, forming an air space doublet. Both the crown and flint elements have a flat 50 degrees minor chord section ground off, similar to the upper objective lens. It is mounted in the lower objective lens mount (5) and is secured in the mount with a clamp ring (6). The clamp ring is secured in the mount with four lockscrews (12).

3. Lower objective lens spacer ring. The lower objective lens spacer ring (7) is placed between the crown and flint elements. Refer, to the upper objective lens spacer ring (84, Figure 7-6) of Section 7F1, Part I, as it is identical in design and purpose.

4. Lower objective lens clamp ring. The lower objective lens spacer ring (6) clamps the lower objective lens (2 and 3) to the shoulder of the mount with sufficient tension to hold it there after the insertion of four lockscrews (12). Refer to the upper objective lens clamp ring (84, Figure 7-6) of Section 7F1 Part I, as it is identical in design.

5. Head prism drive shaft section continuation. The head prism drive shaft section continuation (4) is an extension of the head prism drive shaft section (61, Figure 7-6) of the eighth inner tube section (60). This shaft continuation extends downward through clearance holes in the four bearing flanges of the third inner tube section (1) to the left of the rectangular waveguide slots.

6. Waveguide section continuation. The waveguide section continuation (8) is an extension of the waveguide section (7, Figure 7-6) of the fifth reduced tube section (1). This extension extends the entire length of the third inner tube section and fits in the four rectangular slots in its bearing flanges.

7. Lower air line section continuation. The lower air line section continuation (13) is an extension of the lower air line section (34, Figure 7-7) of the lower part of the fifth inner tube section (19). This continuation extends the entire length of the 3rd inner tube section (1).

b. Second inner tube section. The second inner tube section (14) is made of the same

material and design as the eighth inner tube section (60, Figure 7-8) except that it has an overall length of 21.500 inches. Its upper part is secured to the lower alignment support section of the second inner tube section upper end coupling (17) while at its lower part it is secured to the upper alignment support section

1. Second inner tube section upper end coupling. The second inner tube section upper end coupling (17) is identical to the eighth inner tube section lower end coupling (63, Figure 7-6). This upper end coupling forms a joint between the lower part of the third inner tube section and the upper part of the second inner tube section.

2. Head prism drive shaft section continuation. The head prism drive shaft section continuation (15) is an extension of the head prism drive shaft section (61, Figure 7-6) of the eighth inner tube section (60). This shaft continuation extends the entire length of the second inner tube section (14). One head prism drive shaft noise eliminator (16) is placed on the shaft continuation and is located in the central part of the second inner tube section (14). The lower end of this shaft continuation is undercut to receive the upper part of the head prism drive shaft universal coupling (34) which is secured with a taper pin (36). One head prism drive shaft guide (22A) is located in the central part of the second inner tube section to support the shaft continuation. It is soldered to the flat 50 degrees minor chord wall of this inner tube section.

3. Lower air line section continuation. The lower air line section continuation (29) is an extension of the lower air line section (34, Figure 7-7) of the fifth inner tube section (19). This continuation extends the entire length of the second inner tube section (14). It is soldered to an air line coupling (40) at the upper part of the first inner tube section (31). It is secured to the second inner tube section (14) with a soldered airline strap (28) located in the central part.

4. Waveguide clamp bracket. They waveguide clamp bracket (25) is secured to the upper part of the second inner tube section (14) flush with its upper face. The clamp bracket is retained on the flat 50 degrees minor chord wall with two lockscrews (22). Refer to the waveguide clamp brackets (73, Figure 7-6) of the eighth inner tube section (60) as the waveguide clamp

5. Tape strap. The tape strap (30) is soldered to the periphery of the second inner tube section (14) and is located in the central part. It is placed in the vertical centerline of the tape slots of the bearing flanges. This provides vertical guidance to the change of power shifting wire tapes (35, Figure 7-11).

6. Reducing coupling. The reducing coupling (18) is identical to the eighth inner tube section reducing coupling (64, Figure 7-6), with some exceptions. The reducing coupling is reversed, which necessitates various changes in the bearing flange, such as the various clearance holes and tape slots.

a) Two shifting wire tape slots are located in the flange to the right of the rectangular waveguide slot.

b) The clearance hole located to the left of the rectangular slot is provided for the lower part of the head prism drive shaft section continuation (15).

c) An air line clearance hole is provided for the lower air line section continuation (29), located on the left side of the rectangular wave guide slot.

d) The relative position of six tapped holes and one dowel pin hole in the bearing flange are changed.

Refer to the eighth inner tube section reducing coupling (64, Figure 7-6) of Section 7F1, Part I, for detail concerning the alignment support sections. The upper alignment support section is secured in the lower part of the second inner tube section with 24 lockscrews (20).

c. First inner tube section. The first inner tube section (31) is made of cast phosphor bronze material with an overall length of 18.970 inches. It is provided with an upper bearing flange and a lower flange, with the thickest part of the offset provided with a rectangular waveguide slot in similar manner to the first reduced tube section (51, Figure 7-6). The upper flange is provided with six clearance holes and an inserted dowel pin (38), and is secured to the

The lower flange is provided with seven tapped holes for lockscrews (35) and a dowel pin hole for the insertion of a dowel pin (37). Two cored rectangular slots are provided 180 degrees apart at right angles to the rectangular waveguide slot. The slot on the right side provides clearance for the power shifting wire tapes, while the slot on the left side serves no particular purpose other than to provide the flange with a symmetrical design.

The periphery of this reduced tube section tapers inward from the upper bearing flange down to its lower flange. The upper part is bored straight a sufficient distance to allow for the undercut alignment support section of the reducing coupling (18). The lower part is provided with an undercut alignment support section, which is a sliding fit in the counterbored section in the upper part of the eyepiece skeleton (42, Figure 7-11). The bore is tapered from the straight bored section in the wiper part, in similar manner to the periphery, maintaining a uniform wall thickness to the lower flange. The inside shoulder of the lower flange bore is chamfered. The tapered bore is provided with anti-reflection threads. The wall of this inner tube section is tapered to conform to the convergence of the marginal or oblique cone of light rays extending downward from the lower objective lens (2 and 3).

The upper part of the head prism drive shaft universal coupling (34) couples with the stub section of the lower part of the head prism drive shaft section continuation (15), and is secured together with a taper pin (36) at the upper part of the first inner tube section (31) . The lower part of the universal coupling couples with the head prism drive shaft section (33) and is secured together with a taper pin (36).

The lower part of the lower air line section (39) is coupled to a 2-foot air line section by

7G3. Disassembly of Part I. The lower telescope system assembly Part I is disassembled in the following manner:

1. Separate the third inner tube section (1) from the second inner tube section upper end coupling (17). Remove the 24 lockscrews (10) from the lower part of the third inner tube section. These lockscrews are unscrewed from tapped holes in the upper part of the second inner tube section upper end coupling, and carried out of countersunk clearance holes in the lower part of the third inner tube section. Remove the third inner tube section with the assembled lower objective lens (2 and 3), the lower objective lens mount (5), the lower objective lens clamp ring (6), its lockscrews (12), the lower objective lens spacer ring (7), and the lower objective lens mount lockscrews (9).

2. Remove the four lockscrews (9). These lockscrews are unscrewed from the tapped holes in the lower objective lens mount (5) and carried out of countersunk clearance holes in the third inner tube section.

3. Place a special lower objective lens mount removal jig in the holes provided in the lower part of the lower objective lens mount (5), to allow the lower objective lens mount to be removed.

4. Remove the four lower objective lens clamp ring lockscrews (12). These lockscrews are unscrewed from tapped holes in the lower objective lens clamp ring (6) and carried out of countersunk clearance holes in the objective lens mount (5).

5. Remove the lower objective lens clamp ring (6), sliding it out of the lower objective lens mount (5).

6. Place the lower objective lens mount (5) with the upper face downward, resting the flint element of the lower objective lens (2) on a special padded wooden block (Figure 7-9). The mount will slide down over the padded block with the lower objective lens and

7. Wrap the crown and the flint elements (2 and 3) of the lower objective lens in clean lens tissue and store them in a dry container to prevent scratches and breakage.

8. Remove the two lockscrews (22) from the waveguide clamp bracket (25). These lockscrews are unscrewed from tapped holes in the upper part of the second inner tube section (14) flat 50 degrees minor chord wall and the lower alignment support section of the second inner tube section upper end coupling (17).

9. Separate the second inner tube section upper end coupling (17) from the second inner tube section (14). Remove the 24 lockscrews (21) from the upper part of the second inner tube section. There lockscrews are unscrewed from tapped holes in the lower alignment support section of the second inner tube section upper end coupling, and carried out of countersunk clearance holes in the upper part of the second inner tube section. Remove the coupling from the upper part of the second inner tube section.

10. Separate the second inner tube section (14) from the upper part of the reducing coupling (18). Remove the 24 lockscrews (20) from the lower part of the second inner tube section. These lockscrews are unscrewed from tapped holes in the upper alignment support section of the reducing coupling and carried out of countersunk clearance holes in the lower part of the second inner tube section. Remove the reducing coupling and the attached first inner tube section from the lower part of the second inner tube section.

11. Separate the lower part of the reducing coupling (18) from the upper part of the first inner tube section (31). Remove the six lockscrews (35) from the, upper flange of the first inner tube section. These lockscrews are unscrewed from tapped holes in the reducing coupling flange and carried out of clearance holes in the upper flange of the first inner tube section. Remove the reducing coupling from the upper flange of the first inner tube section.

7G4. Reassembly of Part I. The lower telescope system, Part I is reassembled in the following manner:

2. Reassemble the reducing coupling (18) in the upper flange of the first inner tube section (31). The alignment dowel pin (38) of the first inner tube section upper flange should engage in a reamed hole in the lower flange of the second inner tube reducing coupling to reestablish the factory alignment. Secure them together by the insertion of six lockscrews (35). These lockscrews are inserted in clearance holes in the upper flange of the first inner tube section and screwed into tapped holes in the lower flange face of the reducing coupling.

3. Reassemble the lower part of the second inner tube section (14) on the upper alignment support section of the reducing coupling (18). Secure the coupling to the inner tube section with 24 lockscrews (20). These lockscrews are inserted in countersunk clearance holes in the lower part of the second inner tube section and screwed into tapped holes in the upper alignment support section of the reducing coupling.

4. Reassemble the lower part of the second inner tube section upper end coupling (17) in the upper part of the second inner tube section (14). Secure the coupling of the inner tube section with 24 lockscrews (21). These lockscrews are inserted in countersunk clearance holes in the upper part of the second inner tube section and screwed into tapped holes in the lower alignment support section of the second inner tube section upper end coupling.

5. Reassemble the waveguide clamp bracket (25) to the upper part of the second inner tube section on the flat 50 degrees minor chord wall and secure it with two lockscrews (22). These lockscrews are inserted in countersunk clearance holes in the bracket and screwed into tapped holes in the upper part of the second inner tube section and lower alignment support section of the second inner tube section upper end coupling.

6. Clean the lower objective lens (2 and 3) in similar manner to that noted under Step, 9 of Section 7F4.

7. Place the crown element of the lower objective lens (2) on the padded wooden block

8. Place the lower objective lens spacer ring (7) with the filed flat radius facing downward.

9. Place the flint element of the lower objective lens (3) on the lower objective lens spacer ring with the concave surface resting on the lower objective lens spacer ring. Line up the irregular circumference of the lenses with the spacer ring.

10. Place the lower objective lens mount (5) over the assembled lower objective lens (2 and 3) and the padded wooden block. Turn the complete assembly with the padded block over so that the flint element (3) of the lower objective lens is resting on the shoulder seat in the lower objective lens mount (5).

11. Place the lower objective lens clamp ring (6) in the lower objective lens mount (S) with the flat 50 degrees minor section having a slight radius resting against the crown element face. Secure the upper objective lens clamp ring with four lockscrews (12).

12. Place the assembled lower objective lens mount (5) in the third inner tube section (1) with the lower objective lens clamp ring (6) facing upward.

14. The four lower objective lens mount lockscrews (9) are not inserted in the lower objective lens mount until after final collimation. Place these lockscrews in a small box until ready for securing.

15. Reassemble the lower part of the third inner tube section (1) on the upper part of the second inner tube section upper end coupling (17). Secure the coupling to the inner tube section with 24 lockscrews (10). These lockscrews are inserted into countersunk clearance holes in the lower part of the third inner tube section and screwed into tapped holes in the upper alignment support section of the second inner tube section upper end coupling.

16. Place a canvas boot over the upper end of the third inner tube section (1) and over the lower flange of the first inner tube section (31) to prevent dirt and dust settling on the lenses and inner surface of the cleaned lenses and inner tube sections.

Ill. No.	Drawing Number	Num- ber Re- quired	Nomenclature
1	P-1183-9	2	Shifting wire spindles
2	P-1133-10	2	Shifting wire clamps
3	P-1133-11	2	Shifting wire clamp nuts
4	P-1133-12	4	Shifting wire spindle adjusting nuts
5	P-1160-1	2	Ball bearings for rayfilter drive gear
		2	Ball bearings for eyepiece prism shift gear
		2	Ball bearings for training handle rack gear (right)

Ill. No.	Drawing Number	Num- ber Re- quired	Nomenclature
12	P-1161-5	2	Eyepiece prism actuating gears
13	P-1161-6	2	Eyepiece prism actuating gear shafts
14	P-1163-11	1	Eyepiece prism shift bevel gear key
15	P-1173-3	1	Eyepiece lens clamp ring
16	P-1173-4	1	Eyepiece prism upper clamp ring
17	P-1173-5	1	Eyepiece prism upper retaining plate
18	P-1173-7	1	Eyepiece prism mount
19	P-1173-7A&B	8	B 2 Eyepiece prism mount stem gear racks
20	P-1173-7C	5	Eyepiece prism mount stem gear rack lockscrews
21	P-1173-7A1	4	Eyepiece prism mount stem gear rack dowel pins
22	P-1173-8	1	Eyepiece prism front retaining plate
23	P-1177-7	2	Counterweight strap retaining plates
24	P-1318-1	1	Training handle rack gear and shaft
25	P-1318-8	1	Rayfilter drive male coupling half section
26	P-1403-3	1	Power shifting rack right
27	P-1403-4	1	Power shifting rack left
28	P-1409-1	1	Retaining plate for power shift racks
29	P-1417-2	1	Nipper eccentric eyepiece prism centering ring
30	P-1417-3	1	Front eccentric eyepiece prism centering ring
31	P-1417-4	1	Eyepiece prism front clamp ring
32	P-1475-10	1	Eyepiece prism
33	P-1475-11	1	Eyepiece lens
34	P-1482-2	1	Spiral pinion gear shaft bracket
35	P-1482-6	2	Shifting wire tapes
36	P-1494-1	2	Counterweight straps
37	P-1494-2	1	Counterweight half
38	P-1494-3	6	Counterweight lockscrews
39	P-1494-4	1	Counterweight half
40	P-1495-5	14	Eyepiece skeleton and eyepiece box lockscrews and eyepiece skeleton and first inner tube section lockscrews
41	P-1495-9	1	Eyepiece prism shift bevel gear
42	P-1496-1	1	Eyepiece skeleton

a. Eyepiece skeleton frame. The eyepiece skeleton frame (42) is made of cast phosphor-bronze material with an over-all length of 22.747 inches. It is cast with various cored projections and recesses to accommodate the eyepiece drive mechanism, rayfilter drive mechanism, power shifting mechanism and the prism tilt mechanism.

The upper part of the eyepiece skeleton is provided with small and large shoulder flanges with sufficient bearing surface between flanges to carry the assembled halves of the counter weight (37 and 39) in the optical centerline. The outer circumferences of both flanges are eccentric with the optical axis 0.125 inch. defer to the offset provision in the preceding bearing flanges of the inner tube section couplings, as it offers the same provision for the rectangular waveguide section continuation (43).

The small flange is provided with rectangular slots 180 degrees apart and perpendicular to the rectangular waveguide slot. The slots of the small flange provide the necessary clearance for the counterweight straps (36) while the right rectangular slot also furnishes clearance for the power shifting wire tape (35). The elongated

The large shoulder flange is provided with seven clearance holes and two inserted alignment dowel pins (76). An air line clearance hole is located on the right side of the rectangular waveguide slot to carry the lower part of the lower air line section continuation (39, Figure 7-10). It matches with the air line hole in the eyepiece box (11, Figure 7-12). This lower flange provides the necessary support to carry the upper part of the eyepiece box and is secured to the above flange with seven lockscrews (40).

The upper part of the eyepiece skeleton is provided with two counterbored sections. The small counterbored section provides the necessary clearance for light transmission and is provided with anti-reflection threads. The large counterbored section provides sufficient clearance for the lower alignment support section of the lower part of the first inner tube section (31, Figure 7-10). Both counterbored sections are concentric with the optical axis, as is also the periphery bearing surface between the two flanges for the counterweight's vertical travel. A reamed hole is provided in the base of the eyepiece skeleton frame in the center of a shallow counterbored section, to receive the eyepiece skeleton centering screw (24, Figure 7-12) which extends upward from the eyepiece box base. The centering screw stabilizes the lower part of the eyepiece skeleton in the eyepiece box.

The eyepiece drive mechanism is composed of numerous mechanical internal parts to actuate the eyepiece prism vertically to any diopter

b. Eyepiece prism mount, upper retaining plate, front retaining plate, and prism. 1. Eyepiece prism mount. The eyepiece prism mount (18) provides the necessary body to retain the eyepiece prism (32) and the eyepiece lens (33) in a fixed vertical moving position in the optical axis. The mount has two side walls which prevent the eyepiece prism from sideward motion. Each side wall is provided with four tapped holes in the upper and front faces to retain the eyepiece prism upper retaining plate (17) and the eyepiece prism front retaining plate (22) with four lockscrews each (69).

Each side wall is provided with two raised rail bearings which are a sliding fit into the rail bearings in each inner wall of the eyepiece skeleton frame. The mount is provided with a stem which projects downward from the center part of its rear body. On each side of the mount, the stem gear racks (19) are assembled to the stem projection. Both stem gear racks are maintained in alignment on the stem projection with two alignment dowel pins each (21) The left gear rack is secured with three lockscrews (20), while the right gear rack is secured with two lockscrews (20). The stem gear racks (19) engage with two eyepiece prism actuating gears (12) assembled on the eyepiece prism actuating gear shafts (13). The shafts extend into the front of the center wall through the bearing hole in the gear in the center section and into the rear wall. Each shaft is secured with a lockscrew (65)

2. Eyepiece prism upper retaining plate. The eyepiece prism upper retaining plate (17) is a rectangular plate with a cylindrical projecting. shoulder. The bore is threaded to receive an eyepiece prism upper clamp ring (16) secured with a lockscrew (70). The side facing toward the front is beveled at 45 degrees to form a miter joint with the beveled upper side of the plate.

3. Eyepiece prism front retaining plate. The eyepiece prism front retaining plate (22) is a rectangular plate with a cylindrical projecting shoulder. The bore is threaded to receive an eyepiece prism front clamp ring (31) and the eyepiece lens mount (78).

4. Eyepiece prism. The eyepiece prism (32) is a crown element, with a curvature ground on

c. Eyepiece lens mount and lens. 1. Eyepiece lens mount. The eyepiece lens mount (78) provides an outer wall to retain the eyepiece lens (33) in a concentric position in the eyepiece prism front retaining plate (22). The mount is cylindrical with the lower part undercut and threaded to engage in the internal threads in the eyepiece prism front retaining plate. The threaded shoulder has sufficient length that when the large shoulder of the mount is in a metal to metal contact with the projecting shoulder of the front retaining plate, it also serves to lock the front eyepiece prism clamp ring (31). The mount is bored with a counterbored beveled section with a shallow shoulder remaining as the front wall. The counter bored beveled section conforms to the angle of the eyepiece lens with the outer surface following the same pattern to provide a uniform wall thickness. The lower part of the inside surface of the mount is provided with two additional counterbored sections, one for the periphery of the eyepiece lens (33) and the other threaded for an eyepiece lens clamp ring (15). The clamp ring engages in the internal threaded section in the mount to hold the eyepiece lens and is secured with a lockscrew (70).

d. Counterweight. The counterweight is made up of two halves (37 and 39) of cast brass composition material. It is provided with cored sections, for the insertion of lead. The amount of lead added should conform to the weight of the assembled eyepiece prism mount. The counterweight serves to counterbalance the assembled eyepiece prism mount, and to stabilize the mount in any position of the allowed diopter setting the observer desires. Both halves are assembled together with six lockscrews (38). Body clearance holes are provided in the counterweight half (39) for the lockscrews (38) and their extension into the tapped holes in the counterweight half (37). The counterweight half section (37) is provided with tapped holes to receive the lockscrews (38), a rectangular waveguide slot, a radius clearance provision cut through, and an additional part of the rectangular slot for the head prism drive shaft section continuation (48). An air line clearance hole is provided to the right of the rectangular waveguide slot for the lower air line section continuation (39, Figure 7-10). Each counterweight half is stepped 180 degrees apart, and when assembled it forms a rectangular slot 180 degrees apart. Each rectangular slot carries a counterweight strap (36) secured with four lockscrews (69). The bore of the counterweight is eccentric 0.125 inch with the outer circumference. The offset is necessary for a similar provision as indicated in each preceding bearing flange of the inner tube section couplings. The counterweight slides vertically on the bearing section of the eyepiece skeleton, between the small and large shoulder flanges.

e. Counterweight straps. The two counterweight straps (36) are made of casts phosphor-bronze material with an over-all length of 16.400 inches. The upper part of each counterweight strap is attached to a rectangular slot in each side of the counterweight halves. The lower part of each is provided with a raised gear rack that meshes with each eyepiece prism actuating gear (12) projecting through slots in each side of the

f. Eyepiece prism actuating gears, shift gear, and shift bevel gear. 1. Eyepiece prism actuating gears. The eyepiece prism actuating gears (12) are perpendicular to the optical centerline of the eyepiece skeleton center framework. Both gears are retained with two eyepiece prism actuating gear shafts (13) and secured with lockscrews (65). The actuating gears revolve on the shafts, and are meshed with gear racks of the counterweight straps (36) and the gear teeth of the eyepiece prism mount stem gear racks (19). The right actuating gear is meshed with the teeth of the eyepiece prism shift gear (56) in its upper part, while in its lower part, it is meshed with the teeth of the rayfilter drive gear (11).

2. Eyepiece prism shift gear. The eyepiece prism shift gear (56) has gear teeth cut integral with the shaft in its large shoulder part, while the stub end of the shaft is supplied with a recess keyway. The prism shift gear is mounted in two ball bearings (5) which are mounted in a ball bearing housing (9). An eyepiece prism shift bevel gear (41) fits on the stub end of the shaft over the inserted key (14), and is secured with a lockscrew (68). The complete assembly is assembled into a clearance hole and counterbored recess seat in the right side of the eyepiece skeleton frame rear wall and is secured with four lockscrews (64). Two dowel pins (10) provide a rapid alignment reference for reassembly. The eyepiece prism shift gear extends into the center section of the eyepiece skeleton frame and meshes with the right eyepiece prism actuating gear (13) in its upper part.

3. Eyepiece prism shift bevel gear. The eyepiece prism shift bevel gear (41) attached to

g. The rayfilter drive mechanism. It is composed of numerous mechanical parts forming an internal assembly to synchronize the movement of the rayfilter attachment with the eyepiece drive mechanism-.

1. Rayfilter drive gear. The rayfilter drive gear (11) has gear teeth cut integral with the shaft in its large shoulder part. It is mounted in two ball bearings (5) which are mounted in a ball bearing housing (6). The rayfilter drive male coupling half section (25) fits on the stub end of the rayfilter drive gear shaft and is secured with a taper pin (74). The complete assembly is assembled into a clearance hole in the right side of the eyepiece skeleton frame front center wall, and the flange is secured with four lockscrews (64). Two dowel pins (7) provide a rapid alignment reference for reassembly. The rayfilter drive gear extends into the center section of the eyepiece skeleton frame, and meshes with the right eyepiece prism actuating gear (12) in its lower part. It is located 180 degrees opposite the eyepiece prism shift gear (12). The male coupling half section (25) serves as a thrust collar and couples with the rayfilter drive female coupling section (1, Figure 7-13) attached to the rayfilter drive actuating shaft (8, Figure 7-13) extending inward from the rayfilter drive packing gland assembly in the eyepiece box.

h. The change of power mechanism. The change of power mechanism is composed of numerous mechanical parts forming the internal assemblies for connection with an external attachment for change of power.

1. Right training handle rack gear and shaft. The right training handle rack gear and shaft (24) has gear teeth cut integral with the shaft in the large shoulder part. It is mounted in two ball bearings (5) which are mounted in a ball

The complete assembly is assembled into a clearance hole and counterbored section seat in the right side of the eyepiece skeleton frame and is secured with four lockscrews (64). The training handle rack gear is provided with a milled recess in the form of an inside male coupling section. The male coupling section is recessed to provide clearance for the female coupling section (1, Figure 7-16) attached to the actuating shaft (4, Figure 7-16). The training handle rack gear meshes with the right and left power shifting racks (26 and 27) to provide actuation to the power shifting racks for change of power.

2. Power shifting racks right and left. The power shifting racks (26 and 27) are made of cast phosphor bronze material, each rack having an overall length of 7.375 inches. Both racks are provided with offset arms and hubs to establish the center axis of each hub with proper clearance on each side of the optical centerline, and to provide sufficient clearance for both shifting wire spindle assemblies. The left power shifting rack (27) is provided with gear teeth in the lower straight section in the right side face to mesh with the training handle rack gear (24). The right power shifting rack (26) has gear teeth in the lower straight section in the left side that mesh as in the left power shifting rack.

The arm of the right power shifting rack is offset to the right of the lower straight section and slightly outward. The hub section is offset to the left and slightly outward, with a reamed hole in the center of the hub to carry the shifting wire spindle assembly. The arm of the left power shifting rack is offset to the right and outward. The hub section is offset to the right and slightly outward, with a reamed hole in the center of the hub to carry the shifting wire spindle assembly. Both power shifting racks are carried in the vertical grooves in the right side of the eyepiece skeleton frame. Both racks are, retained in the vertical recess slots with a retaining plate (28) and secured with eight lockscrews (66). The retaining plate is provided with a clearance hole in its central part to accommodate the female

3. Shifting wire spindles. The two shifting wire spindles (1) are made of phosphor-bronze rod material with an overall length of 2 inches. The outer circumference is threaded to carry two shifting wire spindle adjusting nuts (4) on the lower part. The upper part has a 16 degrees countersunk section in its center axis, to receive a 14 degrees tapered shifting wire clamp (2) and the shifting wire clamp nut (3) on its threaded periphery. The center axis of the spindle has a clearance hole for the phosphor-bronze wire extension of the shifting wire tape (35). Each shifting wire spindle fits in the reamed hole in either power shifting rack hub section and has an adjusting nut on its upper and lower part in contact with the upper and lower faces of the shifting rack hub section.

4. Shifting wire clamps. The two shifting wire clamps (2) are made of corrosion-resisting steel material. A clearance hole is provided through the center axis of each, with a sawed slot the depth of which corresponds to the length of the tapered part. The upper part is undercut and forms an alignment support section in the clamp nut. The tapered slotted section when assembled in the upper countersunk section in the spindle, closes as the clamp nut is tightened and in this manner clamps the phosphor bronze wire extension of the power shifting wire tape (35).

5. Shifting wire clamp nuts. The two shifting wire clamp nuts (3) are made of phosphor-bronze material. The center axis of each has a clearance hole for the phosphor bronze wire extension of the shifting tape (35). In the upper part a small counterbore is provided as an alignment support section with the 1arge counterbored section threaded to engage on the threaded periphery of the shifting wire spindles (1).

i. The prism tilt mechanism. It is composed of numerous mechanical internal parts, to operate the head prism for all degrees of elevation and depression. This is accomplished with internal connecting linkage and a suitable connecting external attachment.

1. Spiral drive housing. The spiral drive housing (44) is made of cast phosphor-bronze material. This housing carries the spiral drive

2. Spiral pinion gear shaft. The spiral pinion gear shaft (47) is made of corrosion-resisting steel material with an over-all length of 7 inches. The upper stub section carries the lower part of a head prism drive shaft universal coupling (59) secured together with a taper pin (72). The upper part of the universal coupling with a keyseat, is a sliding fit on the lower stub section of the head prism drive shaft section continuation (48) over an inserted woodruff key (46). The upper part of the spiral pinion gear shaft is supported with a bracket (34) at an angle of 9 degrees. The bracket is secured to the rear wall of the eyepiece skeleton with three lockscrews (60).

The lower undercut part of the spiral pinion gear shaft extends through a large spiral drive housing ball bearing clamp ring (51), and two large ball bearings (58) mounted in the large projection of the spiral drive housing (44) at a 9 degrees angle. The spiral pinion gear shaft is provided with an inserted woodruff key (46) which extends into the spiral pinion gear keyway and axis hole (49). The long hub of the pinion gear is secured snugly against the center ball bearing race with a taper pin (73). The stub section of this shaft has a small straight shoulder and a small threaded section. The small straight shoulder extends into a small ball bearing (57) mounted in the small projection of the spiral drive housing (44) at a 9 degrees angle. Two thrust nuts (54) engage on the threaded periphery of the shaft, an provide a means of eliminating the axial play of the small ball bearing (57).

3. Spiral pinion gear. The spiral pinion gear (49) is made of corrosion-resisting steel material with an overall length of 1.218 inches. Its center axis is reamed to slide on the spiral pinion gear shaft (47) with an inside keyway its entire length. The external part is provided with a small and large hub, separated with a shoulder. The shoulder is provided with right-hand spiral

4. Large spiral drive housing ball bearing clamp ring. The large spiral drive housing ball bearing clamp ring (51) is a cylindrical ring of nominal wall thickness, threaded on its outer circumference, to engage in the internal threaded section in the upper part of the large projection of the spiral drive housing (44). Two shallow slots are provided in the upper face 180 degrees apart for the insertion of a special wrench. This clamp ring retains both large ball bearing races (58) against a counterbored shoulder seat in the large ball bearing projection of the spiral drive housing and is secured with a lockscrew (61).

5. Spiral bull gear shaft. The spiral bull gear shaft (45) is made of corrosion-resisting sting steel material, with an overall length of 2.150 inches. A large shoulder is provided with two projecting lugs to form a male coupling section to connect with a female coupling section (1, Figure 7-15) of the left training handle packing gland assembly extending inward from the eyepiece box. The main body section of this shaft fits in two large ball bearings mounted in the outer wall of the spiral drive housing (44). An inserted woodruff key (46), in the shaft fits into the spiral bull gear (50) with a keyseat. A small straight shoulder is threaded to carry a retaining nut (53). The stub end of the shaft fits into a small ball bearing (57) mounted in the inner wall of the spiral drive, housing. The stub end of the shaft extends through a clearance hole beyond the ball bearing counterbored seat into a reamed hole in the offset side wall of the eyepiece skeleton.

6. Spiral bull gear. The spiral bull gear (50) is made of phosphor-bronze material. Its center

7. Small spiral drive housing ball bearing clamp rings. The two small spiral drive housing ball bearing clamp rings (52) are cylindrical with nominal wall thickness, with their outer circumference threaded to engage in the internal threaded section in the outer side wall of the spiral drive housing (44). Each ring is provided with two shallow slots in the outer face 180 degrees apart for the insertion of a special wrench. The inner clamp ring secures the large ball bearing races against the counterbored shoulder seat in the spiral drive housing, while the outer clamp ring serves as a lock ring to maintain the adjustment of the inner ring.

8. Spiral bull gear guard. The spiral bull gear guard (55) is placed over the front face of the spiral bull gear (50) and centered. It is secured to the upper and lower walls of the spiral drive housing (44) with two lockscrew (71). The guard prevents the gear teeth of the spiral bull gear from damage when removing the eyepiece box from the eyepiece skeleton or vice versa.

7H2. Disassembly of the eyepiece skeleton assembly Part II. This procedure is performed in the following manner:

1. Remove the eyepiece prism mount (18) by pulling it out vertically clear of the rail bearings in the inner side walls of the eyepiece skeleton (42).

2. Remove the lockscrew (70) from the eyepiece prism upper retaining plate (17). This lockscrew is unscrewed from a tapped hole in the

3. Remove the four lockscrews (69) from the eyepiece prism upper retaining plate (17). These lockscrews are unscrewed from tapped holes in the upper side walls of the eyepiece prism mount (18). Remove the eyepiece prism upper retaining plate with the eyepiece prism upper clamp ring (16). Remove the upper eccentric eyepiece prism centering ring (29) and unscrew the eyepiece prism upper clamp ring (16) from the above retaining plate.

4. Remove the assembled eyepiece lens mount (78) with the eyepiece lens (33), eyepiece lens clamp ring (15), and its lockscrew (70) by unscrewing the eyepiece lens mount from the eyepiece prism front retaining plate (22).

5. Remove the lockscrew (70) from the eyepiece lens mount (78) and the eyepiece lens clamp ring (15). This lockscrew is unscrewed from the tapped hole in the eyepiece lens clamp ring and carried out of the countersunk clearance hole in the eyepiece lens mount.

6. Remove the eyepiece lens clamp ring (15) unscrewing it from the eyepiece lens mount (78).

7. Remove the eyepiece lens (33) from the eyepiece lens mount (78) and wrap the eyepiece lens in clean lens tissue. Place it in a dry container to prevent scratches and breakage.

8. Use clean lens tissue to remove the eyepiece prism {32) slicing it out of the eyepiece prism mount (18) from the upper end. Wrap the eyepiece prism in clean lens tissue and store it in a dry container to prevent scratches and breakage.

9. Remove the four lockscrews (69) from the eyepiece prism front retaining plate (22). These lockscrews are unscrewed from tapped holes in the front side walls of the eyepiece prism mount (18). Unscrew the eyepiece prism clamp ring (16) from the eyepiece prism front retaining plate (22). Remove the front eccentric eyepiece prism centering ring (30).

10. Remove the three lockscrews (20) from the left prism stem gear rack (19) removing the rack. These lockscrews are unscrewed from tapped holes in the stem of the eyepiece prism mount (18).

12. Remove the eight lockscrews (66) from the power shifting rack retaining plate (28). These lockscrews are unscrewed from the center raised portion on the power shift side of the eyepiece skeleton. Remove the retaining plate.

13. As the power shifting rack retaining plate (28) is removed, the power shifting racks ( 26 and 27) are removed from the right side of the eyepiece skeleton frame (42).

14. Remove the two shifting wire spindle adjusting nuts (4). Unscrew them from the lower part of the shifting wire spindles (1) of the power shifting racks (26 and 27). The shifting wire spindle assemblies consist of two shifting wire spindles (1), two shifting wire clamps (2), two shifting wire clamp nuts (3), and four shifting wire spindle adjusting nuts (4).

15. Remove the head prism drive shaft universal coupling taper pin (72) from the head prism drive shaft universal coupling (59) and the spiral pinion gear shaft (47). Remove the head prism drive shaft universal coupling (59) from the upper part of the spiral pinion gear shaft (47).

16. Remove the three lockscrews (60) from the spiral pinion gear shaft bracket (34). These lockscrews are unscrewed from tapped holes in the rear wall of the eyepiece skeleton frame. Remove the spiral pinion gear shaft bracket (34) sliding it off the upper part of the spiral gear shaft (47).

17. Remove the three short and two long lockscrews (62 and 63) from the spiral drive housing (44). These lockscrews are unscrewed from tapped holes in the left side of the eyepiece skeleton frame. Remove the assembled spiral drive housing from the left side of the eyepiece skeleton frame (42).

18. The spiral drive housing (44) is disassembled by following the procedure of Steps 19 to 29 inclusive. Remove two spiral bull gear guard lockscrews (71). These lockscrews are

19. Remove the spiral bull gear retaining nut lockscrew (67). It is unscrewed from a tapped hole in the spiral bull gear retaining nut (53).

20. Remove the spiral drive housing large ball bearing clamp ring lockscrew (61). The lockscrew is unscrewed from a tapped hole in the large bearing projection in the rear part of the spiral drive housing (44).

21. Remove the taper pin (73) by driving it out of the spiral pinion gear (49) and the spiral pinion gear shaft (47).

22. Remove the taper pin (73) from the spiral bull gear (50) and its shaft (45).

23. With the use of a special wrench, remove the two spiral drive housing small ball bearing clamp rings (52). These clamp rings are unscrewed from the left side face of the spiral drive housing (44).

24. With the use of a special wrench, remove the spiral drive housing large ball bearing clamp ring (51). This ball bearing clamp ring is unscrewed from the large ball bearing projection in the rear part of the spiral drive housing (44). Carry the large ball bearing clamp ring off over the spiral pinion gear shaft (47).

25. Remove the two spiral pinion gear thrust nuts (54). Unscrew these thrust nuts from the lower end of the spiral pinion gear shaft (47).

26. Release the spiral buff gear retaining nut (53) and tap the spiral bull gear shaft (45) toward the left side wall in a series of steps allowing the retaining nut to touch the inner side wall of the spiral drive housing (44) each This procedure is followed until the retaining nut is removed from the threaded periphery of the spiral bull gear shaft. This method prevents the spiral bull gear teeth from becoming damaged. 27. Tap the spiral bull gear shaft (45) out of the spiral drive housing a center punch in the center of the small end of the shaft. Remove the spiral bull gear shaft with the two assembled large ball bearings (58) and a spiral gear key (46) remaining in the spiral bull gear shaft. Remove the spiral bull gear (50) and the spiral

28. Remove the spiral pinion gear shaft (47), pulling it out carefully from the spiral pinion gear (49) and the small spiral pinion gear shaft ball bearing (57). Remove the spiral pinion gear. The large spiral pinion gear shaft bail bearings (58) and the spiral pinion gear key (46) remain on the shaft.

29. The spiral bull gear and the spiral pinion gear shaft small ball bearings (57) remain in the spiral drive housing.

30. Remove the six lockscrews (66) from each counterweight strap retaining plate (23). These lockscrews are unscrewed from the raised shoulder on each side of the eyepiece skeleton. Remove each of the retaining plates.

31. Remove the four lockscrews (69) from the upper part of each counterweight strap (26). These lockscrews are unscrewed from tapped holes in the rectangular slots in each counterweight half (37 and 39). Remove each counterweight strap.

32. Remove the six lockscrews (38) from the counterweight half (39). These lockscrews are unscrewed from the tapped holes in the counterweight half. (37). Remove both counterweight halves (37 and 39) from between the large and small flanges of the upper part of the eyepiece skeleton (42).

33. Remove the four lockscrews (64) from the eyepiece prism shift gear ball bearing housing (9). These lockscrews are unscrewed from the tapped holes in the counterbored section seat in the rear wall of the eyepiece skeleton. Remove the assembly consisting of the following: eyepiece prism shift gear ball bearing housing (9), two eyepiece prism shift gear ball bearings (5), eyepiece prism shift gear and integral shaft (56), eyepiece prism shift bevel gear key (14), its lockscrew (68), eyepiece prism shift bevel gear (41), and two dowel pins (10).

34. In case the assembly is damaged or corroded, it will require disassembly. This is accomplished by following the disassembly procedure of Steps 34 to 37 inclusive. Remove the lockscrew (68) from the eyepiece prism shift bevel gear (41). This lockscrew is unscrewed from a

35. Remove the eyepiece prism shift bevel gear (41) from the eyepiece prism shift gear integral shaft (56) and remove the inserted eyepiece prism shift bevel gear key (14) from the integral shaft.

36. Remove the eyepiece prism shift gear integral shaft (56) from the center races of the two ball bearings (5), carrying it out of the small end of the eyepiece prism shift gear ball bearing housing (9).

37. Remove the two eyepiece prism shift gear ball bearings (5) from both ends of the eyepiece prism shift gear ball bearing housing (9).

38. Remove the four lockscrews (64) from the rayfilter drive gear ball bearing housing (6). These lockscrews are unscrewed from tapped holes in the counterbored raised boss face of the eyepiece skeleton center wall. Remove the assembly consisting of the rayfilter drive ball bearing housing (6), two rayfilter drive gear ball bearings (5), rayfilter drive gear and integral shaft (11), rayfilter drive male coupling half section (25), its taper pin (74), and two dowel pins (7).

39. In case the assembly is damaged or corroded, it will require disassembly. This is accomplished by following the disassembly procedure of Steps 39 to 42 inclusive. Remove the taper, pin (74) from the rayfilter drive male coupling half section (25) and the rayfilter drive gear and integral shaft (11).

40. Remove the rayfilter drive male coupling half section (25) from the integral shaft of the rayfilter drive gear (11).

41. Remove the rayfilter drive gear integral shaft (11) from the center races of two ball bearings (5), carrying it out of the small end of the rayfilter drive gear ball bearing housing (6).

42. Remove the two rayfilter drive gear ball bearings (5) from both ends of the rayfilter drive gear ball bearing housing (6).

43. Remove the four lockscrews (64) from the right training handle rack gear ball bearing housing (6). These lockscrews are unscrewed

44. In case the assembly is damaged or corroded, it will require removal. This is accomplished by following the disassembly procedure of Steps 44 to 47 inclusive. Remove the taper pin (75) from the right training handle rack gear retaining collar (8) and the right training handle rack gear integral shaft (34).

45. Remove the right training handle rack gear retaining collar (8) from the right training handle rack gear integral shaft (24).

46. Remove the right training handle rack gear and shaft (24) from the center races of the two ball bearings (5), carrying it out from the large shoulder flange end of the right training handle rack gear ball bearing housing (6).

47. Remove the two training handle rack gear ball bearings (5) from both ends of the right training handle rack gear ball bearing housing (6).

48. Remove the two lockscrews (65) from their contact in the spot faces in two eyepiece prism actuating gear shafts (13). These lockscrews are unscrewed from tapped holes in a raised shoulder on each side of the eyepiece skeleton.

49. Remove the eyepiece prism actuating gear shafts (13) and the eyepiece prism actuating gears (12). The shaft and gears slide out easily.

7H3. Reassembly of the eyepiece skeleton assembly, Part II. his procedure is performed in the following manner.

1. Place both eyepiece prism actuating gears (12) in the center section of the eyepiece skeleton (42). Reference marks on both gears and shaft must be noted for correct reassembly to corresponding reference marks on the eyepiece skeleton frame.

2. Place both eyepiece prism actuating gear shafts (13) in the reamed holes in the center and the rear frame wall of the eyepiece skeleton.

3. Reassemble both counterweight halves (37 and 39) on the bearing surface between the small and large flanges of the eyepiece skeleton (42). The cored part of each counterweight half faces upward. Secure both halves of the counterweight together by inserting six lockscrews (38). These lockscrews are inserted in clearance holes in the counterweight half (39) and screwed into tapped holes in its opposite counterweight half (37).

4. Place each counterweight strap (36) through each elongated slot in the large shoulder flange of the eyepiece skeleton located 180 degrees apart. Secure each counterweight strap to the rectangular slotted face on opposite sides of the counterweight with four lockscrews each (69). These lockscrews are inserted in countersunk clearance holes in each counterweight strap and screwed into tapped holes in the opposite rectangular slotted faces of the assembled counterweight.

5. Engage the lower end of each counterweight strap gear race (36) in mesh with each eyepiece prism actuating gear (1,2) in the grooved section between two rectangular raised bosses.

6. Reassemble the counterweight strap retaining plates (23) over each counterweight strap (36) on the rectangular raised bosses on opposite side walls of the eyepiece skeleton frame. Secure each retaining plate with six lockscrews (66). The lockscrews are inserted into countersunk clearance holes in the retaining plate and screwed into the tapped holes in the rectangular raised bosses of the left and right side-walls of the eyepiece skeleton.

7. Reassemble the eyepiece prism shift gear ball bearings (5) into the eyepiece prism shift gear ball bearing housing (9) from both ends.

8. Reassemble the eyepiece prism shift gear integral shaft (56) into the center races of the

9. Place the eyepiece prism shift bevel gear key (14) in the keyway in the eyepiece prism shift gear integral shaft (56).

10. Reassemble the hub end of the eyepiece prism shift bevel gear (41) on the inserted key (14) and the stub end of the eyepiece prism shift gear integral shaft (56) up against its shoulder. Secure the bevel gear to the shaft by the insertion of a lockscrew (68). This lockscrew is screwed into a tapped hole in the hub of the above bevel gear and extends into a spotted recess in the stub end of the shaft (56).

11. Reassemble the eyepiece prism shift gear mechanism assembly into the clearance hole and the counterbored section seat in the rear wall of the eyepiece skeleton frame. The dowel pins (10) of the housing engage in the reamed holes in the counterbored section seat in the eyepiece skeleton frame. Secure the eyepiece prism shift gear ball bearing housing (9) with four lockscrews (64). These lockscrews are inserted in countersunk clearance holes in the housing and screwed into tapped holes in the counterbored section seat in the eyepiece skeleton frame. Check the reference mark of the eyepiece prism shift gear (56) to engage with a corresponding reference mark on the right eyepiece prism actuating gear (12).

12. Reassemble the rayfilter drive gear ball bearings (5) into both ends of the rayfilter drive gear ball bearing housing (6).

13. Reassemble the rayfilter drive gear integral shaft into the center aces of the rayfilter drive gear ball bearings (5) from the small end of the rayfilter drive gear ball bearing housing (6). The shaft extends through the ball bearing races with the shoulder of the rayfilter drive. gear (11), a metal-to-metal contact with the inner ball bearing race.

14. Reassemble the rayfilter drive male coupling half section (25) on the stub end of the rayfilter drive gear integral shaft (11) and secure the coupling to the shaft with a taper pin (74).

16. Reassemble the right training handle rack gear ball bearings (5) in both ends of the right training handle rack gear ball bearing housing (6).

17. Reassemble the right training handle rack gear integral shaft (24) into the center races of the right training handle rack gear ball bearings (5) from the large end of the ball bearing housing. The shaft extends through the center ball bearing races with the shoulder of the right training handle rack gear a metal-to-metal contact with the inner ball bearing race.

18. Reassemble the right training handle rack gear retaining collar (8) to the stub end of the right training handle rack gear integral shaft (24), and secure the retaining collar to the shaft with a taper pin (75).

19. Reassemble the right training handle rack gear mechanism assembly into the bored hole and counterbored section seat in the right side of the eyepiece skeleton frame. Secure the right training handle rack gear ball bearing housing (6) with four lockscrews (64). These lockscrews are inserted in countersunk clearance holes in the housing and screwed into tapped holes in the counterbored section seat in the right side of the eyepiece skeleton frame.

20. The spiral drive housing is reassembled by following Steps 20 to 29 inclusive. Place the spiral pinion gear (49) between the large and small bearing projection of the spiral drive housing (44) with the large hub of the spiral pinion gear fitting into the large bearing projection.

21. Reassemble the spiral pinion gear shaft (45) with two assembled large ball bearings (58)

22. Reassemble both spiral pinion gear thrust nuts (54). Screw them on the lower threaded periphery of the spiral pinion gear shaft (47). Tighten both thrust nuts. This prevents any axial motion of the spiral pinion gear (49) between the small spiral pinion gear shaft ball bearings (57) and the large spiral pinion gear shaft ball bearings (58).

23. Insert a taper pin (73) into the large hub of the spiral pinion gear (49) and its shaft (47) for its securement.

24. Reassemble the spiral drive housing large ball bearing clamp ring (51), carrying it on over the spiral pinion gear shaft (47). Screw the above ball bearing clamp ring into the internal threaded section of the large bearing projection, using a special wrench. Tighten the clamp ring until no axial motion is noticed in the spiral pinion gear shaft (47).

25. Place the spiral bull gear (50) in the spiral drive housing (44) with the longer hub facing the small spiral bull gear shaft ball bearing (57). Check the reference mark of the spiral pinion gear (49) to make sure that the reference tooth of this pinion gear will engage between the two reference teeth of the spiral bull gear (50).

26. Place the spiral bull gear shaft (45) with the assembled large spiral bull gear shaft ball bearings (48) and the inserted spiral bull gear key (46) through the outer wall of the spiral. drive housing (44) in the spiral bull gear and its keyseat (50). Place the spiral bull gear retaining nut (54) between the hub of the spiral bull gear and the inner wall of the spiral drive housing. With the retaining nut held with a pair of tweezers, the spiral bull gear shaft assembly is pushed in to allow the inserted key (46) to engage in the keyseat in the spiral bull gear (40). The retaining nut is screwed on the spiral bull gear shaft in a series of tightening steps. As the retaining nut reaches the hub of the spiral bull gear each time, the assembly is pushed in. The

27. Insert a taper pin (73) into the hub of the spiral bull gear (50) and its shaft (4S). Align the retaining nut tapped hole with the spotted recess in the spiral bull gear shaft. The retaining nut will require a slight further tightening. When the alignment is ascertained, insert the spiral bull gear retaining nut lockscrew (67). The lockscrew is screwed into a tapped hole in the above retaining nut and extends into the spotted recess in the spiral bull gear shaft (45).

28. Place the inner of two small spiral drive housing ball bearing clamp rings (52) in the internal threads in the outer left side wall of the spiral drive housing (44). Tighten the inner clamp ring until there is no axial motion noticeable in the spiral bull gear shaft (45). Reassemble the second small clamp ring in the same manner, as this clamp ring serves to lock the inner clamp ring. A special wrench is required for tightening the clamp rings.

29. Place the spiral bull gear ward (55) over the spiral bull gear (50) and secure it to the front of the spiral drive housing (44) with two lockscrews (71). These lockscrews are inserted in countersunk clearance holes in the guard and screwed into tapped holes in the front walls of the spiral drive housing (44).

30. Reassemble the spiral drive housing assembly the offset face of the left side of the eyepiece skeleton frame. Secure the assembly with three short and a two long lockscrews (62 and 63). These lockscrews are inserted in clearance holes in the spiral drive housing (44) and screwed into tapped-holes in the left side of the eyepiece skeleton frame.

31. Reassemble the spiral pinion gear shaft bracket (34), sliding it on over the upper part

32. Reassemble the lower part of the head prism drive shaft universal coupling (59) to the upper part of the spiral pinion gear shaft (47). Secure the coupling to the shaft with a taper pin (72).

33. Place the power shifting racks (26 and 27) in the vertical slots in the right side wall of the eyepiece skeleton frame. The gear racks are placed with their lower ends even with the base of the eyepiece skeleton frame. The right training handle rack gear and shaft (24) reference mark should coincide with the reference marks on each power shifting rack. Place the shifting rack gear retaining plate (28) over the power shifting racks on the raised center bosses. Secure the shifting rack retaining plate with eight lockscrews (66). These lockscrews are inserted in countersunk clearance holes in the retaining plate and screwed into tapped holes in the raised bosses on the right side of the eyepiece skeleton frame.

34. Reassemble both shifting wire spindle assemblies in the hubs of the power shifting racks (26 and 27). The shifting wire spindle assemblies consist of the following: two shifting wire spindles (1), two shifting wire clamps (2), two shifting wire clamp nuts (3), and four shifting wire spindle adjusting nuts (4). Assemble the two shifting wire spindle adjusting nuts (4) up to the lower hub faces of the power shifting racks by screwing them on the lower part of the shifting wire spindles (1).

35. Reassemble the right eyepiece prism stem gear rack (19) with dowel pins (21) on the right side of the eyepiece prism mount stem (18). Secure it with two lockscrews (20) from the opposite side of the eyepiece prism mount stem (18). These lockscrews are inserted in countersunk clearance holes in the stem and screwed into tapped holes in the right eyepiece prism stem gear rack (19).

36. Reassemble the left eyepiece prism mount stem gear rack (19) with dowel pins (21) on the

37. Reassemble the eyepiece prism front retaining plate (22) on the front face of the eyepiece prism mount (18). Secure it with four lockscrews (69). These lockscrews are inserted in countersunk clearance holes in the retaining plate and screwed into tapped holes in the front face of the eyepiece prism mount side walls.

38. Clean the eyepiece prism (32) in similar manner to the procedure followed for cleaning the lenses in the various reduced and inner tube sections. Place the eyepiece prism in the eyepiece prism mount (18) from the upper end, with the shortest radius toward the eyepiece lens side.

39. Reassemble the eyepiece prism upper retaining plate (17) on the upper face of the eyepiece prism mount (18). Secure it with four lockscrews (69). These lockscrews extend into tapped holes in the upper face of the eyepiece prism mount side walls.

40. Place the upper eccentric eyepiece prism centering ring (29) and the upper eyepiece prism clamp ring (16) in the eyepiece prism upper retaining plate (17). The beveled side of the centering ring should bear to the curvature of the prism. The retaining ring is screwed down on the upper eccentric eyepiece prism centering ring until the lockscrew holes coincide. Insert the lockscrew (70) in a countersunk clearance hole in the eyepiece prism upper retaining plate and screw it into a tapped hole in the upper eyepiece prism clamp ring.

41. Place the front eccentric eyepiece prism centering, ring (30) to bear on the prism in similar manner to the upper centering ring, and assemble the eyepiece prism front clamp ring (31) into the eyepiece prism front retaining plate (22). The clamp ring is screwed down on

42. With the counterweight at the extreme lower position, the assembled eyepiece prism mount (18) is placed in the rail bearings of the eyepiece skeleton and moved downward. Move the counterweight upward to engage the prism actuating gears (12) with the eyepiece prism stem gear rack (19). The upward movement of the counterweight will not cause the engagement of both the eyepiece prism actuating gears (12) with the eyepiece prism stem gear racks (19).

43. Clean the eyepiece lens (33) in similar manner to the procedure followed for cleaning lenses in the various reduced and inner tube sections.

44. Reassemble the eyepiece lens (33) into the eyepiece lens mount (78) with the concave radius facing the shoulder seat in the mount.

45. Place the eyepiece lens clamp ring (15) in the internal threaded section in the eyepiece lens mount (78). Screw the clamp ring into the mount until the lockscrew holes coincide. Secure the clamp ring with a lockscrew (70). This lockscrew is inserted in a countersunk clearance hole in the mount and screwed into a tapped hole in the eyepiece lens clamp ring.

46. Reassemble the assembled eyepiece lens mount (78) into the internal threads in the eyepiece front retaining plate (22). Screw the eyepiece lens mount into the retaining plate until the shoulder of the lens mount is a metal-to-metal contact with the shoulder of the retaining plate.

47. PRECAUTION: a) The essential travel of the assembled counterweight halves (37 and 39) and the eyepiece prism mount (18) is 24 mm.

b) The essential travel of the power shifting racks should be approximately 29 mm.

c) The essential travel of the head prism drive shaft should be 2 1/3 turns or 11.5 mm movement of the head prism actuating rack (65, Figure 7-5) of the skeleton head assembly.

a. Eyepiece box. The eyepiece box (11) is made of cast-phosphor bronze material with an

The upper face has seven tapped holes, two reamed dowel pin holes, and an air line clearance hole to match with holes in the large shoulder flange of the eyepiece skeleton.

The inside diameter of the upper flange section is bored to allow it to slide on the small alignment shoulder provision of the large shoulder flange of the eyepiece skeleton. The inside bore of the upper flange section is provided with three cored recesses, allowing clearance for the waveguide in the rear part and on both sides of the center axis for the counterweight straps (36, Figure 7-11).

The alignment dowel pin reamed holes provide a rapid alignment reference for the reassembly of the eyepiece box to the large shoulder flange of the eyepiece skeleton. The dowel pins maintain the angular alignment of the eyepiece skeleton and the eyepiece box, which is established in similar manner to the Type II periscope.

The upper part of the eyepiece box is a sliding fit in the lower part of the outer tube (2, Figure 7-2). A short keyway with concave corners is provided in the front center axis of the shoulder preceding a threaded shoulder. An outer tube and eyepiece box angular alignment key (17) is a pressed fit in the milled keyway. This alignment key maintains the angular alignment of the eyepiece box, in a vertical inside keyway in the lower part of the outer tube.

The upper face of the threaded shoulder is provided with a triangular annular groove similar to the Type II periscope to allow the rubber gasket (22) to be compressed in this groove, by the triangular annular ridge detail on the outer tube when joining them together by the main coupling (12).

All the various openings will be described under each individual assembly in the following manner:

b. Main coupling. The main coupling (12) is made of cast phosphor bronze and is 2.531 inches

The main coupling connects the lower part of the outer tube to the eyepiece box. A soft rubber gasket (22) fits between the triangular annular ridge detail of the outer tube and the corresponding triangular annular groove in the shoulder joint of the eyepiece box (11).

The compression of the soft rubber gasket (22), by means of the coupling being tightened, joins the two faces together, thus causing the gasket to follow the triangular annular ridge and its corresponding groove to provide a hermetically sealed joint. Two lockscrews (21) usually located on opposite sides of the main coupling, screw into tapped holes in the main coupling and extend into spotted recesses in the outer tube to prevent the coupling from unscrewing, and thus maintain the hermetical seal of this joint.

The main coupling has four sets of twin holes equally spaced of shallow depth. These holes accommodate a special spanner wrench provided with, twin prongs for the breaking or making up of the joint.

c. Air valve bodies. The two air valve bodies (4) are identical to the air valve bodies (15, Figure 4-29) used in the Types II and III periscopes. The two air INLET and OUTLET plugs (3), the two air valve screws (5) and the two 3/16-inch steel balls (6) are also identical, to the bubble numbers 14, 16, and 17, Figure 4-29. Refer to Section 4M1. A soldered air line section (23) 8 1/2 inches long (not shown in Figure 7-12) connects the cylindrical wall seat section in the eyepiece box in the same manner as the 4 3/4-inch length soldered air line section of the Types II and III periscopes.

e. Eyepiece window assembly. The eyepiece window assembly (29) is identical to the eyepiece window assembly (27, Figure 4-29) of the Types II and III periscopes. Refer to Section 4M1.

f. Rayfilter drive packing gland assembly. The rayfilter drive packing gland assembly (25) is assembled to the front bored hole and square recess seat in the front of the eyepiece box (11). It serves the same purpose and function as the rayfilter drive packing gland assembly (24, Figure 4-29) used in the Types II and III periscope except that it is not a spring type. Refer to Section 4M1. Use the rubber gasket and lockscrews (3 and 11, Figure 7-13). The rubber gasket maintains the hermetical seal of this assembly along with its hycar packing.

g. Eyepiece drive packing gland assembly. The eyepiece drive packing gland assembly (26) is secured in the eyepiece box (11) with a sealing rubber gasket and lockscrews (3 and 10, Figure 7-14) in similar manner to the eyepiece drive packing gland assembly used in the Types II and III periscopes. Refer to (25, Figure 4-29) Section 4M1. It is not a spring type. This packing gland provides an internal connection with eyepiece prism shift bevel gear (41, Figure 7-11) of the eyepiece skeleton assembly at the inner part, and an external connection with the focusing knob assembly (Figure 4-39). The rubber gasket maintains the hermetical seal of this assembly along with its hycar packing.

h. Left training handle packing gland assembly. The left training handle packing gland assembly (27) with the rubber gasket and lockscrews (3 and 10, Figure 7-15) is assembled to the eyepiece box (11) in similar manner to the left training handle packing gland assembly used in the Types II and III periscopes. Refer to Figure 4-29, Section 4M1, as it serves the same purpose and function except that it is not a spring type. The rubber gasket maintains the hermetical seal of this assembly along with its hycar packing.

j. Bottom plug assembly. The bottom plug assembly (30) is assembled in the bored hole and counterbored section seat on a rubber gasket (3, Figure 7-17) in the base of the eyepiece box located in the rear part of the center axis. The bottom plug assembly provides an external connection with the electronic device attached to the eyepiece box bottom flange plate (13), and an internal connection with the waveguide section continuation (43, Figure 7-11). The bottom plug housing rubber gasket (3, Figure 7-17) is placed between the bottom plug housing shoulder flange and the counterbored section seat in the eyepiece box (11). The bottom plug housing is secured to the gasket and the counterbored section seat with 12 lockscrews (7, Figure 7-17). The rubber gasket (3, Figure 7-17) maintains the hermetical seal of this assembly along with the bottom plug window (5, Figure 7-17) and the two bottom plug window rubber gaskets (4, Figure 7-17).

k. Angular alignment key. The angular alignment key (17) is made of monel metal, having a nominal length, thickness, and width, with the upper and lower corners rounded. It is a force fit in the machined recess keyway in the front centerline of the eyepiece box (11). This key is a sliding fit in the inside keyway In the lower part of the outer tubs. It provides the angular maintenance of the emerging light rays within the prescribed tolerance of five minutes of arc with the entering light rays.

1. Angular alignment determination of the eyepiece box to the eyepiece skeleton. The correct location of the two inserted dowel pins (76, Figure 7-11) of the eyepiece skeleton (42, Figure 7-11) large shoulder flange and their proper engagement in reamed dowel pin holes of the eyepiece box (11) is determined through the procedure followed under the same subject in Section 4M1.

n. Eyepiece box bottom flange plate. The eyepiece box bottom flange plate (13) is made of cylindrical cast phosphor-bronze material inch thick and has a diameter of 9 inches. It is provided with eight equally spaced clearance holes in a diameter circle of 8.203 inches for eight 3/8 inch X 20 threads per inch hexagon bolts and nuts. The above clearance holes match the corresponding clearance holes in the electronic device flange, with a rubber gasket placed between both flanges. The bottom flange plate is provided with five clearance holes. Each hole has a counterbored recess in the bottom face to provide clearance for the heads of five bolts (16). These bolts extend into tapped holes in the base of the eyepiece box. Two inserted dowel pins (20) fit into the inserted dowel pin bushings (15) in the base of the eyepiece box to reestablish factory alignment upon reassembly.

The upper face of the bottom flange plate is provided with a narrow slot of shallow depth for the insertion of a rubber gasket (14). The narrow slot conforms to the irregular outer circumference of the eyepiece box base. The rubber gasket (14) prevents water from entering the bottom plug assembly.

A clearance hole of 2 1/2 inches in diameter is located in the rear central half of the plate, and provides sufficient clearance for the attachment of an electronic device projection that connects to the bottom plug assembly.

o. Rayfilter stowage case assembly. The rayfilter stowage case assembly (31) rests on the eyepiece box bottom flange plate (13) and is secured to it with one of the bolts and nuts of the eight used in attachment of the electronic device.

p. Name plate. The name plate (9) is of the same dimensions and material as the name plates (20, Figure 4-29) used in the Types II

q. Anchor screw pins. The two anchor screw pins (8) are identical to the anchor screw pins

All four are similar in design, with the exception of the rayfilter drive stuffing box body.

These four packing gland assemblies are of an improved design using hycar synthetic rubber packing and should provide a much longer service life than the flax packing type. However, these glands are carefully run in at the factory and should not be disassembled or the shaft removed unless pressure tests or service experience indicate the need of replacement. The following sections outline the procedure to follow should repacking be found necessary.

7J2. Description of the rayfilter drive packing gland assembly. Figure 7-13 shows this picking gland assembly. All bubble numbers in Sections 7J2, 3, and 4 refer to Figure 7-13 unless otherwise specified.

Ill. No.	Drawing Number	Num- ber Re- quired	Nomenclature
1	P-1318-9	1	Female coupling section
2	P-1318-9A	1	Phosphor-bronze wire
3	P-1405-6	1	Stuffing box body rubber gasket
4	P-1503-2	4	Brass spacer washers (0.020 inch)
5	P-1503-3	4	Hycar packing spacers
6	P-1503-4	1	Stuffing box body
7	P-1503-5	1	Packing retainer
8	P-1503-6	1	Rayfilter drive actuating shaft
9	P-1503-7	1	Rayfilter drive actuating gear
10	P-1506-43	1	Packing retainer lockscrew
11	P-1506-53	4	Stuffing box body lockscrews

Figure 7-13. Rayfilter drive packing gland assembly.