SUB-SECTION 4A
HYDRAULlC SYSTEM
this position, the oil in the brake chamber is allowed to
The swing brake is used to lock the swing reducer so that
return to tank and the brake springs set the brake.
the swing motor cannot turn, thus preventing the revolving
upper portion of the machine from turning.
MAIN WINCH CIRCUIT. The main winch control valve
NOTE
directs hydraulic oil from the pump to the winch motor.
The direction in which the valve spool is shifted will deter-
The upper of the machine will swing freely if the
mine whether the winch will lift or lower a load. The speed
swing brake is not applied.
of winch operation is determined by the amount of oil
metered through the control valve to the winch motor.
The swing brake pedal is shown in the released position. In
this position, oil is allowed to enter the brake chamber and
release the brake. When the operator depresses the swing
AUXILIARY WINCH CIRCUIT. The auxiliary winch con-
brake pedal, the oil in the brake chamber is allowed to
trol valve directs hydraulic oil from the pump to the winch
motor. The direction in which the valve spool is shifted
return to tank and the brake springs set the brake.
will determine whether the winch will lift or lower a load.
The speed of winch operation is determined by the amount
The swing brake lock is shown in its normal operating posi-
of oil metered through the control valve to the winch
tion. When the machine is not working or is shut down, the
motor.
swing brake lock should be placed in the locked position. In
4A-12
