Adapter, Yoke and Fixture Assemblies

TM 55-4920-201-14

cable, discrepancies have no affect on the balance

normal and should not be interpreted as incipient

indications. Stabilize the suspended assembly and

failure.

5-10. Dial Indicator (7HELO55 Kit). Check

note the indicator bushing position in relation to the

indicator and mounting stand parts for mutilation

black indicator disc. An arbor that exhibits balance

or corrosion. Check stand assembly for proper

eccentricity to the point of tangency illustrated in

functioning and security of indicator positioning.

view C, figure 1-28, is acceptable and completely

Check indicator head for smoothness and con-

serviceable. However, overlapping circles as shown

tinuity of indicating action.

in view D, figure 1-28, are an indication that the

5-11. Scope Support Assembly (7HEL056 Kit).

arbor is out-of-balance beyond acceptable limits

Visually check scope support assembly for

(providing indicator bushing interference and dash-

mutilation or corrosion. Raise index pin and check

pot oil descrepancy possibility have been

rotation of scope support on index plate for

eliminated). Out-of-balance arbors shall be

smoothness and security. Check indexing action of

removed from service and forwarded to the

index pin in 0-, 90-, 120-, 180-, 240-, and 270-

manufacturer for repair.

degree positions. Insert scope in scope wheel and

5-4. Adapter, Yoke and Fixture Assem-

check tilting action of scope wheel for smoothness

blies. Visually check all surfaces for nicks, burrs,

and security. Check locking action of scope lock

scratches or corrosion; particularly, make sure

screw.

pilot and mating surfaces are free of surface defects.

If necessary, check snug slip fit of an assembly in

5-12. Alignment Scopes (7HEL056 Kit). Visually

question on the balancing arbor (mating surfaces

check for mutilation or corrosion. Check fits in

shall be thoroughly cleaned). If an assembly is

scope wheel for smoothness and security. Visually

suspect due to tampering or inadvertent damage,

check lenses for cleanliness, mutilation, and

security of mounting.

accomplish a routine balance check of the assembly

5-13. MAINTENANCE.

on a serviceable arbor assembly. All adapter, yoke

5-14. General. Careful preservation of pre-

and fixture assemblies are precisely balanced by the

cision-finished piloting surfaces of kit compo-

manufacturer prior to shipment and should retain

nents against corrosive attack or accidental

thin precise balance unless parts are misused. Refer

surface damage constitutes the most effective

to section VII for increasing the sensitivity setting

preventive maintenance.

(vertical height) of the adapter, yoke or fixture

5-15. Correction of Minor Mutilation or Corrosion.

assembly on the arbor, if a balance check is being

Local stoning and polishing of arbor and adapter

made.

piloting surface, to remove raised portions of minor

5-5. Cones, Bushings, Spacers, Etc. Make sure all

nicks, dents, burro, or scratches may be performed

parts are free of superficial surface defects such as

in most cases without seriously affecting accuracy

burrs, nicks, scratches and corrosion, especially at

of piloting fits. Complete blending out of larger

the pilot and mating surfaces.

nicks and dents or removal of large areas of

5-6. Quick-Disconnect Couplings. Install coupling

corrosion having a perceptible depth is not

on suspension rod end and check for freedom of

recommended. Individual parts that require more than

action and positive locking. Check release action.

correct ion of minor mutilation or corrosion should be

(Refer to section IV for operation). If binding or

interference is found, carefully inspect assembly for

returned to next higher echelon for inspection and

evaluation.

possible foreign matter. (For corrective in-

structions, refer to paragraph 5-16).

WARNING

Cleaning may be toxic. Use in well-

5-7. Suspension Cables. Visually check cables for

ventilated area. Avoid prolonged inhala-

fraying, kinks, mutilation, and security of swaged

tion of fumes or direct contact with skin.

fittings.

Do not, use solvent near open flame or in

5-8. Hydraulic Pump Assembly. With pump in

area where very high temperatures prevail.

horizontal position, check for proper functioning.

5-16. Quick-disconnect Couplings (7A050 and

(Refer to section IV for operation). If malfunction

7HEL053 Kits). Binding or erratic action of the

of assembly is indicated, check reservoir fluid level.

(Refer to paragraph 5-22).

quickdisconnect coupling due to presence of dirt or

chips may usually be corrected by agitation of the

5-9. Stand and Hoist Structure. Visually check

complete coupling assembly while immersed in

stand and hoist structure for free fits of all mating

solvent, Specification P-D-680, or equivalent.

parts. If interference is found check for mutilation

Following such immersion, allow assembly to drain

or deformation of affected parts. Check wood case

for 15 minutes, then immerse complete assembly in

for splits, cracks, or loosening of component parts.

a medium lubricating oil, Military Specification

Visible deflection of hoist structure under load is

5-2 Change 1