OP-755 Part 2 Pages 197-401 - Personal Page of GENE SLOVER

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relief valve in the B-end will open to by-pass A-end pressure.
If overtravel occurs at the lower unloading station and the
car comes to rest on safety stop 19, check valve 40 will open
to by-pass motor lines 23 and 41 and thus prevent B-end rotation
and unwinding of the cable. In such contingency, before
lowering can be attempted it is necessary to hoist the car
slightly in order to withdraw the safety stop. If the car
overtravels at the loading station and comes to rest on the
lower buffer, check valve 40 will by-pass the main circuit
lines.
69. System vents. - Air vent 71 enables bleeding of air
from the stroke control cylinder when the unit is started after
it has been drained and refilled. Vent 72 bleeds the brake
cylinder. Vent 73 bleeds air from the dashpot assembly.
MAINTENANCE INSTRUCTIONS
70. The powder' hoist assemblies are to be operated and
ma.lrrt.aLned, including periodic exe r cLs e , adjustment and lubrication,
in accord with the regulations of the Ordnance Manual,
the general instructions as to installation' and maintenance
as given in" chapter XV, and the specific instructions below.
71. Operating precautions. - Before operating the hoist
under load and before attempting, to pass powder bags inspect
and service the hoist assembly as follows:
( a) Observe oil level in the power circuit supply
tank. Replenish if necessary. Use oil specified
in paragraph 72.
(b) Check oil level in the supply tank for the upper
door and dog locking operating system.Use
oil specified in paragraph 72.
(c) Check liquid level in the lower buffer liquid
system. Use liquid specified in paragraph 74.
(d) Verify all lubrication.
(e) Inspect the loading trays, car trays and upper
door, for burr or other def or-ma tion that might
tear powder bags.
(f) Inspect the hoist drum. Remove burrs.
(g) Inspect the condition of the hoist rope and
its fastenings.
(h) Start the motor and operate the car and doors
through a full cycle in servo and then in man-