HYDRAULIC SYSTEM OPERATION (Contd)
SHEAVES - Grooved wheels that guide hoist cable through boom.
HOIST MOTOR ASSEMBLY - Converts hydraulic power back into mechanical power needed to turn the hoist
UPPER ROLLER ASSEMBLY - Prevents cable from contacting inner boom during winding/unwinding.
CRANE HOIST CABLE DRUM - Is turned by the worm gear in hoist motor assembly. Drum unwinds cable when
turning toward front of vehicle. Drum winds cable when turning toward rear of vehicle.
HOIST CONTROL LEVER - Manual control attached to the control valve that determines hydraulic oil flow for the
raising and lowering action of the crane hoist cable and hook. Lever is pulled back to raise cable and hook and
pushed forward to lower cable and hook.
HOIST CONTROL VALVE - Two-way hydraulic valve located under the hoist control lever directs fluid from the
hydraulic pump to the hoist motor assembly and back through the valve to the hydraulic oil reservoir.