Chassis Tilt Indicator System; Drive Orientation System; Transport Position Sensing System; Beyond Transport - Drive Speed Cutback System - JLG 600AJ Service And Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE

3.7 CHASSIS TILT INDICATOR SYSTEM

The Chassis Tilt Indicator System measures the turntable angle
with respect to level ground. The control system compares the
reading to a pre-set turntable tilt angle value. When the
machine is in transport position refer Transport Position Sens-
ing System procedure for detail, it can travel at up to maximum
speed until it tilts more than 8.0 degree, then the system will
limit the drive speed to maximum displacement mode (slow
drive speed).
However, when the machine is out of transport position and
the turntable tilts more than the pre-set value, the boom func-
tions can only run in creep speed mode and with the drive
function disabled. The operator must return the machine into
transport mode to continue drive the machine.
By factory default, the tilt sensor pre-set value for 660AJ (8 ft.)
is 4 degree, but it need to select between 4.0 degree, and 3.0
degree by JLG hand held Analyzer. By factory default, the tilt
sensor pre-set value for 660AJ (7 ft.) is 3 degree.
Previously, it could be selected by JLG hand held analyzer so
that the machine could drive at maximum displacement mode
(slow speed) when out of transport position and tilted beyond
pre-set turntable tilt angle value. By regulations, this will not
have allowed for ANSI or CE markets.

3.8 DRIVE ORIENTATION SYSTEM

The Drive Orientation System (DOS) is intended to indicate to
the operator conditions that could make the direction of
movement of the chassis different than the direction of move-
ment of the drive/steer control handle.
The system indicates to the operator the need to match the
black and white directional arrows on the platform control
panel to the arrows on the chassis. The system uses a proximity
switch mounted on the hydraulic swivel, an indicator light and
a spring return override switch on the platform display panel.
The proximity switch trips when the turntable is swing +/- 45
degrees off center of the normal driving position. This occurs
roughly when the main boom is swing past a rear tire.
When the turntable is in the normal drive position with the
boom between the rear tires, no indications or interlocks are
made. When the machine is actively driving when the turnta-
ble is swing past the switch point, the system is ignored until
drive/steer is released. When drive is initiated with the boom
swing past the switch point, the DOS indicator will flash, and
the drive/steer functions will be disabled. The operator must
engage the DOS override switch to enable Drive/steer (high
drive will remain disabled). When the DOS is enabled, the DOS
indicator will be illuminated continuously, and a 3-second
enable timer will be started and will continue for 3 seconds
after the end of the last drive/steer command. If the timer
expires, the DOS override switch must be re-engaged to
enable drive/steer.
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3.9 TRANSPORT POSITION SENSING SYSTEM

The transport position sensing system consists of two limit
switches capable of recognizing position of the tower and
main boom. The tower elevation switch is activated when the
tower upright is raised 40 in. to 42 in. from stowed position
and reset when lowered 25 in. to 30 in. from activated position.
The main boom elevation switch is activated when the main
boom reaches 0 to 5 degree above horizontal and reset when
the main boom is lowered 4 to 9 degree below horizontal.
This system uses switches with "positive opening" contacts.
These switches are used in a way that requires switch contacts
to be physically broken to the open position when the
machine is in the "unsafe" condition. When the machine is in
the "safe" condition, the switch must be allowed to return to
the closed state. This requires switch arm cams to be posi-
tioned in a way that the switch arm is actuated while the
machine is in the "unsafe" condition and the switch arm is free
while the machine is in the "safe" condition.
The position of the articulated jib not considered. This system
used to control the following systems:
1.

Beyond Transport - Drive Speed Cutback System

2.

Drive/Steer - Boom Function Interlock System

3.10 BEYOND TRANSPORT - DRIVE SPEED CUTBACK
SYSTEM
When the boom is positioned beyond the transport position
as described in Transport Position Sensing System, the drive
motors are automatically restricted to their maximum dis-
placement position (slow speed). See the Tilt Indicator System
for interaction with the tilt sensor.
3.11 DRIVE/STEER – BOOM FUNCTION INTERLOCK
SYSTEM
The Drive/Steer - Boom Function Interlock System uses the
Transport Position Sensing System to sense when the boom is
out of the transport position. All controls are simultaneously
functional when the booms are within the transport position
as on the standard machine.
When the boom is beyond the transport position, the control
functions interlocked to prevent simultaneous operation of
any boom function with drive/steer. The first function set to be
operated while in this mode, becomes the master function set.
In other words, while operating drive/steer functions the
boom functions are inoperable. Likewise, while operating
boom functions drive/steer functions are not in operation.
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