Gradall 534B (9020-7317) Service Manual - Manual (Page 71)

The inching feature allows the operator, when
carrying a load, to move the handler very slowly for
maneuvering in tight places.
To operate the inching feature, the operator
depresses the brake-inching foot pedal (A)
approximately 1/2" to 1". This creates movement of
the linkage (B) making contact with the low torque
inching switch (D). As this first movement occurs
and physical contact is broken, the switch is
energized and it activates the low torque inching
solenoid valve (E). This sends pilot circuit oil down
to the de-clutch valve (F) on the transmission and
the transmission de-clutches and there is no power
to the front axle.
As the linkage (B) continues to move, the arm on the
inching valve moves. This movement causes pilot
GRADALL LOED MATERIAL HANDLER 534B SYSTEM OPERATION
INCHING
control pressure to bleed off to tank, thereby
metering the Forward/Reverse valve to neutral.
As the operator continues to depress the brake-
inching pedal (A) and the inching valve (C) rotates,
the pressure controlling the Fwd/Rev Valve varies.
Depending on the stroke of the plunger, in the Fwd/
Rev control valve varying, volume of oil is routed
on to the series/parallel valve and to the rear drive
motors.
The further down the operator depresses the brake-
inching pedal, the lower oil volume goes to the
motors.
As the operator continues to depress the brake-
inching pedal, the front axle brakes are applied and
normal braking occurs.
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