TM-9-2320-428-10
TRUCK, CARGO, 8X8, M977
TECHNICAL MANUAL; OPERATOR'S MANUAL
JUNE 2009
TM-9-2320-428-10 - Page 142 of 1072
CRANE OVERVIEW - Continued
Individual control panels, boom-hydraulic cylinder arrangements, and lifting capacities are
different.
All cranes are powered from the vehicle's hydraulic system.
All are equipped with outriggers for stability during operation.
All cranes use a combination of hinged joints and telescoping members to give them their
motions.
The hydraulic-powered hoisting winch has an automatic brake to prevent accidental
lowering of the load.
CRANE OPERATING INSTRUCTION PLATE LOCATIONS
NOTE
Refer to stowage and decal/data plate guide for more information on plate
locations.
The crane operating instruction plates are located on the heater compartment cover in the
cab at each of the fixed operating stations.
The outrigger leg signs are located on each of the outrigger cylinders.
The load capacity signs are located at the main and auxiliary control panels, and on M984A
they are located on the wrecker body rear stowage box doors.
CRANE ELECTRICAL SYSTEM
Material handling cranes for models M977, M984A, and M985 all have overload shutdown
and/or tilt warning (unstable) systems.
When M977, M985, and M984A cranes are overloaded, the overload system will
automatically shut off power to telescope boom out, raise boom, or hoist load higher. The
M977 and M984A overload system will also prevent lowering the boom. An overload
condition can be corrected by lowering the boom. An overload condition can be corrected
by lowering load to ground or other supporting surface. All functions will be restored in
approximately six seconds.
The crane electrical system is supplied with power by the vehicle 24 VDC system.
The junction box on the crane connects and distributes the various control circuits of the
crane.
Tilt warning, outrigger extended warning, and remote control systems are electronically
controlled.
END OF WORK PACKAGE
TM 9-2320-428-10
0016
0016-2
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