Gradall 544D-10 (9136-4142) Operation Manual - Manual (Page 25)

Form No. 20220 z z z z z 544D-10 Owner/Operator Manual
General
The Material Handler covered by this Manual is equipped with hydrostatic drive.
From the operator’s standpoint, operation is similar to driving a vehicle equipped
with an automatic transmission.
Major components of the system include a front drive axle with a differential
and planetaries. The differential receives torque from a variable-displacement
piston pump and a motor.
This combination of components eliminates the need for a conventional
mechanical transmission and also provides inching travel.
These handlers also have piston motors to provide torque to rear-wheel drive
hubs, as well as an electrically-controlled valve which functions to restore
tractive effort if conditions cause a wheel to spin.
Operation
Normal Travel. Direction of travel is selected by moving forward/reverse lever
forward for forward travel, backward for reverse travel. Move lever to center
position for “Neutral”. (See Figure 3-1 for layout of controls)
If hydrostatic drive system senses increased travel load, the system will
compensate automatically by reducing travel speed to match load and engine
RPM.
Inching Travel: Inching travel is provided to permit slow travel speed while
maintaining high engine speed for other handler functions.
The service brake/inching travel pedal controls inching travel.
The upper portion of pedal travel actuates a valve which controls travel pump
output. The greater the pedal travel, the less the pump flow; the slower the
travel.
The lower portion of pedal travel actuates the service brake. The greater the
pedal travel, the stronger the brake application. Travel flow is further reduced
when brakes begin to apply. (See Figure 7-1)
Four-Wheel Drive: When required by travel conditions, rear-wheel (four-
wheel) drive can be engaged by moving switch to “4x4” position. Return unit
to two-wheel drive by moving switch to “4x2” position.
Four-wheel drive can be engaged and disengaged while traveling.
When parking brake is applied, four-wheel drive is disabled.
Traction-Lock Switch: This switch (pedal) controls the traction-lock valve
which functions to restore tractive effort when a wheel spins in four-wheel
drive.
When switch pedal is depressed and held, traction-lock valve functions to cause
delivery of full drive pressure to wheels of other axle, regardless of low pressure
at spinning wheel.
DO NOT engage traction-lock function on improved surfaces. Unit must be in
four-wheel drive to engage the traction-lock function.
DO NOT engage traction-lock function while wheels are turning. Return engine
to idle, engage traction-lock and increase RPM. Disengage after traction resumes
while in motion.
DRIVE TRAIN 10.0
WARNING !
Bring handler to a complete stop
before shifting forward/reverse
lever when carrying a load. A
sudden change in direction of travel
could reduce stability and/or cause
load to shift or fall.
WARNING !
Practice inching/braking in a safe,
open area until you are thoroughly
familiar with response of machine
to pedal travel.
Never disengage rear hubs
except when activating tow-
bypass procedure.
CAUTION !