Snorkel TB125J - Manual (Page 51)

Chapter 8 – Operation
T125J/TB125J – 0192214 51
Driving and Steering
Danger
The aerial platform can tip over if it becomes un-
stable. Death or serious injury can result from a
tip-over accident. Do not drive an elevated aerial
platform on soft, uneven, or sloping surfaces. Do
not drive four wheel drive machines on grades that
exceed 30 percent.
For operation of four wheel drive machines on grades
up to 30 percent, it is recommended that the main boom
be near horizontal and the jib elevated just enough to
provide adequate ground clearance.
A 30 percent grade is a 36″ (0.91 m) vertical rise in 10′
(3.05 m) horizontal length.
Avoid driving with the platform over the front (steer) end
of the chassis. In this position the machine is difficult to
control because:
drive and steer control movements and their result-
ing machine movements are reversed.
when driving fast, sudden turns or stops produce
more severe reactions to platform occupants.
more turning space is required to prevent the
platform from colliding with obstacles several feet
beyond the path of the tires.
Warning
Death or serious injury can result from improperly
driving or steering the aerial platform. Read and
understand the information in this manual and on
the placards and decals on the machine before op-
erating the aerial platform on the job.
The blue and yellow arrows on the chassis indicate the
direction the chassis will move when the drive or steer
control is moved toward the corresponding color.
When the machine is in the stowed position, with the
booms centered between the rear wheels, the direction
of drive and steer control movement corresponds with
the direction of chassis movement.
When the turntable is rotated from the stowed position,
with the booms to either side of or in front of the chassis,
the direction of control movement does not correspond
with the direction of chassis movement.
To avoid confusion, always drive to the work area or
move between work areas with the turntable and booms
in the stowed position. After arriving at the work area,
the booms may be positioned to the side or the front
of the chassis for final positioning. Always look in the
direction of movement as indicated by the directional
arrows on the chassis.
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Use the following procedure to operate the drive and
steer functions.
1. Determine the desired drive range for the specific
driving conditions.
Use high range when traveling across firm, flat,
level surfaces. High range can only be activated
when the booms are stowed. High range is for
high speed, low torque operation.
Use low range for driving on loading ramps or
other steep grades and when safety consider-
ations demand slow deliberate machine move-
ment. Low range is for low speed, high torque
operation.
2. Step down on the platform foot switch.
3. Push the drive joystick forward to move the chas-
sis forward, the direction of the blue arrow. Pull the
joystick backward to move the chassis backward,
the direction of the yellow arrow. The drive speed
is proportional to the joystick position.
4. To stop drive motion, return the joystick to neu-
tral.
5. Push the drive joystick to the right to steer to the
right, the direction of the yellow arrow. Push the
joystick to the left to steer to the left, the direction
of the blue arrow.
Note
The steering wheels are not self-centering. The machine
must be driving to steer the wheels and must be driving
fast enough to release the brakes for steering to work.
Set the steering wheels straight ahead after complet-
ing a turn.
6. After driving to the desired location, release the
foot switch, or push the emergency stop button to
apply the parking brakes.
Drive Speeds
The drive speed is proportional to the joystick position.
The farther the joystick is moved, the faster the travel
speed.
Always slow down and shift the drive system to low
range before traveling over rough terrain or any sloped
surface.
Drive speed ranges are interlocked through a limit switch
that senses the main boom position. When the boom
is elevated up to midway, only the low drive speed will
work. When the boom is elevated to midway or above,
only the creep drive speed will work.
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