Gradall 534B (9103-1390) Service Manual - Manual (Page 62)

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 1/4"
- 1/2". 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 (C) moves. This movement causes pilot
I N C H I N G
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 the oil volume going 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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