TM 10-3950-672-10
SECTION 4
PRINCIPLES OF OPERATION
4-1.
GENERAL.
The Model AP308T hydraulic crane is fully self-contained. All crane functions are either electrically or
hydraulically controlled, and hydraulically operated. The main functions are raising and lowering the boom, extending or
retracting the boom, raising and lowering loads with the hoist, swinging the boom, and extending and retracting the
outriggers. Hydraulic cylinders activate the elevation, telescope, and outrigger systems. The hoist and swing systems
are driven by hydraulic motors.
A diesel engine provides drive power for the main and steering hydraulic pumps and also drives an alternator
which supplies electrical power for control, accessory, and lighting systems. The engine also provides power to the front
drive axle through a transmission, to drive the crane.
Hydraulic flow and electrical power are transferred from the carrier to the superstructure by a hydraulic swivel
with an electrical collector ring located at the center of rotation.
4-2.
MAJOR COMPONENTS AND SYSTEMS.
a. Cab Assembly. The fully enclosed cab is all steel with tinted safety glass windows throughout. The cab contains
all controls and indicators for traveling and craning operations including outrigger control and level indicator.
Access to the enclosed cab is via a hinged left side door which features a keyed lock and lockable sliding glass
window. The crane is equipped with a door holding device which retains the door in the open position. The cab
also contains the heater and defroster, electric windshield wiper, and a 10 BC-rated 2.75 lb (1.25 kg) fire
extinguisher. The operator's seat features a hinged, padded armrest, fore/aft adjustment track, and a three-
position height adjustment lever.
b. Carrier Frame Assembly. The frame assembly is of hi-strength steel, all welded reinforced construction with
integral outrigger boxes front and rear and full width decking. A rear pintle hook is provided.
c. Engine. The diesel engine is housed in the engine compartment located to the rear of the crane. The engine is
used to provide crane mobility, drive the hydraulic pump, supply electrical power to charge the battery, and
provide power for crane control circuits, accessories, and lighting. All controls for the engine are located in the
cab. The on-condition (OC) intervals for changing the engine lubricating oil and filter will be controlled (after the
warranty period), by the Army Oil Analysis Program (AOAP).
d. Fuel Tank. A single 35 gal. (132.4 L) total capacity and 30 gal. (113.5 L) gauge level capacity fuel tank is
mounted on the right side of the crane. The tank is equipped with a lock-type filler cap, a fuel level sender unit,
and a
4-1
