Drive Speeds; Motion Warning Alarm; Four Wheel Drive; Gradeability - Snorkel TB66JRT Operator's Manual

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 indi-

cated by the directional arrows on the chassis.
Use the following procedure to operate the drive and
steer functions.
1. Determine the desired drive range for the specific
driving conditions. Place the switch in the appro-
priate position to achieve the desired drive wheel
operation.
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 oth-

er steep grades and when safety considerations
demand slow deliberate machine movement. Low
range is for low speed, high torque operation.
2. Step down on the platform foot switch.
3. The drive speed is proportional to the joystick posi-
tion.
• 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.
4. To stop drive motion, return the joystick to neutral.
5. The drive joystick controls the two front wheels to
steer the aerial platform.
• Push the drive joystick to the right to steer to the
right, the direction of the yellow arrow.
TB66J – 0083740
• Push the drive joystick to the left to steer to the
left, the direction of the blue arrow.
Note
The steering wheels are not self-centering. Set the steer-
ing wheels straight ahead after completing 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

Drive speed ranges are interlocked through a limit switch
that senses the main boom position.
When the boom is elevated, only the slowest drive

speed will work regardless of the drive range switch
position.
To avoid a sudden speed change from high to low el-

evated boom speed, always bring the machine to a stop
before raising the booms from the stowed position.
Warning
The potential for an accident increases when safety
devices do not function properly. Death or serious
injury could result from such accidents. Do not alter,
disable, or override any safety device.
Do not use the aerial platform if it drives faster than
1 mph (1.6 km/h), or 44 feet (8 m) in 30 seconds, when
the booms are elevated from the stowed position.

Motion Warning Alarm

The optional motion warning alarm sounds loud intermit-
tent beeps when the drive joystick is in the forward or
reverse position.

Four Wheel Drive

The machine may be equipped with a four wheel drive
system. This system operates full time and requires no
action by the operator.
Four wheel drive machines have a "4x4" decal on each
side of the chassis and all four of the wheel hubs are
drive hubs and look the same.

Gradeability

Machine gradeability refers to the maximum slope that
the aerial platform is capable of travel under practical
conditions. It is based on mathematical calculation, but
it also takes into account the practical application.
At any given moment when driving the machine on a
slope, at least one, if not all, of the factors contributing
to achieving theoretical gradeabilty will not be at opti-
mal performance. For example, tire contact may not be
the same at each drive wheel or the slope conditions
may not be optimal, which would then allow for loss of
traction.
Chapter 8 – Operation
53