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

HOIST
N~
LOWER
SUPPLY
TANK
LEGEND
MAIN SYSTEM-
A-END OlSPLACEMENT_ _ _ _ ~:~:~:~;..v)
RACK LOWERING &ACK PRESSURE
[A-EIIOSUCTICN) ._. __ ~~
CR.ltDLE .ltNDPAWL SYSH':Mo-
CRtDLE OPERAHlG HIGH PRESSURE (~:,;:~~~·.v)
SUPPLYTANKHEAO c--=-~
M G y
Fig. 46 - Hoisting Projectiles.
Lowering Empty Rack. Opening Cradle.
In order to obtain this operating cycle with its high
pressures and at other periods permit the motor and
system to l1idlel1,but at the same time provide for
the pawl operating circuit, the three relief valves
have functional arrangement as follows:
(0) with the pilot and shut-off valve at l1Hoistl1
and the cradle control valve neutral, the pump
and circuit are "idlinfj,". (See fig. 45.) Pressure
flows straight through the 800 and 400
pound relief valves and lifts the 25 pound relief.
The latter valve functions in this arrangement
for purpose of maintaining slight
pressure above the pawl control operating piston
IIJl1 and the tripping cam operating piston IIHl!
to block any possibility of pawl lowering
action. This pressure also operates to hold
p