Abstract: The back hitch assembly for a lift or tower crane includes a tension sensing device which regulates the pressure delivered to the boom stop or hold back cylinders such that as the boom hoist line and back hitch become slack when the load line is relieved more pressure is delivered to the cylinders to counteract the rearward pull on the boom or tower due to the suspended weight of the masts and equalizer assemblies.

Abstract: A load handling crane is disclosed having a demountable self-propelled transport assembly including a central car body portion and detachable transverse beams, side beams, crawler assemblies and power source. Hydraulic jacks and push cylinders are mounted on the beams to facilitate detaching the components of the assembly. The power source includes an internal combustion engine and a pair of hydraulic pumps.

Abstract: A rotatable bed for a load handling device including yoke-shaped side frames each having an integral jaw member depending therefrom to which is detachably connected an arcuate beam carrying a plurality of hook rollers adapted to roll on the underside of a roller path on the device. Each end of the arcuate beam is slidably carried on link spanning one of the jaws and is adjustable thereon.

Abstract: A power lowering system for a hoist drum including a hydraulic motor for rotating the drum in a lowering direction and hydraulic feedback means connected to a modulated torque converter for automatically applying opposing torque to the drum when heavy loads are lowered. A variable displacement pump supplies hydraulic fluid to the motor so that the load is lowered at a rate determined by the displacement of fluid supplied to the motor. A flow restriction is provided in the feedback means to the torque converter actuator to dampen cyclical variations in the application of opposing torque. Multiple hoist drums may be automatically clutched to the hydraulic motor and torque converter when separate manual control levers are initially moved in either the hoisting or lowering direction and an automatic brake release may also be employed.

Abstract: A mobile crane with rotating bed, mast, gantry and gantry backhitch is arranged for disassembly and ease of transport without unreeving the boom hoist rigging by collapsing the backhitch, folding the gantry back onto the backhitch, pinning together the backhitch, gantry and boom hoist assembly -- which includes the boom hoist drum and motor, and releasing the gantry, backhitch and boom hoist assembly from the rotating bed. A bracket is fixed to the gantry to provide an anchoring point for the equalizer assembly normally secured to the boom.

Abstract: A rotational drive assembly including a pair of pinion gears journalled on idler shafts disposed laterally on either side of a drive shaft and meshing with the teeth of a drive gear and a ring gear. The drive shaft is universally journalled for rotation and for permitting a limited range of movement of the drive gear toward and away from the ring gear to substantially equalize tooth contact between the drive gear and each of the pinion gears as the drive shaft is rotated. A slotted bearing may be provided to preclude excess lateral movement of the drive shaft.