Abstract: The back hitch assembly for a lift crane includes hydraulic cylinders for raising the pivotally mounted gantry members and masts. Counterweight lift links are connected between the gantry and the counterweight and the back hitch cylinders may be used to mount and demount the counterweight and the boom hoist winch. The masts, gantry members and back hitch cylinders may be folded back over the bed of the crane for low profile transport or they may be demounted to further reduce weight.

Abstract: A self-propelled drive mechanism for a crawler crane or the like including a variable displacement pump and one fixed and one variable displacement motor for each crawler assembly. The displacement of the variable displacement motor may be regulated to alter the combined driving torque and speed imparted by the motors to the crawler assemblies and includes automatic self-balancing feedback means for maintaining the hydraulic pressure within predetermined limits.

Abstract: A self-erecting mast and boom for a lift crane including self-storing mast cylinders for erecting the mast and rotating a pivoted boom carrier into position to receive the boom which may then be raised by the boom hoist mechanism of the crane. A back hitch assembly including hydraulic cylinders is employed to initially raise the mast and the gantry members which may be lowered into horizontal position to reduce the crane profile for self-propelled transport between job sites.

Abstract: A crane assembly which, in heavy lifting configuration, has a platform with boom carrier and counterweight support rotatably mounted on a ring with the mounting including a king pin removably secured to the ring. For portability, the king pin and sections of the ring are removed and a transporter run within the ring and beneath the platform. The platform will easily accept a variety of hoisting machinery. Not only are the boom, mast and ring suitable for other crane configurations, but also the counterweight support and boom carrier are standard subcombinations held rigid with the platform through links defining triangular frames.

Abstract: A load handling device is disclosed having an improved swing drive assembly including a hydraulically driven pivotally mounted swing drive pinion biased against a segmented ring gear by a hydraulic actuator with a guide roller adjacent the pinion engaging a guide flange concentric with the ring gear to limit the maximum tooth engagement between the pinion and ring gear and thereby provide essentially constant backlash on the pinion gear regardless of eccentricities or other irregularities in the ring gear during swing drive operation. When the swing drive pump is shut down a bypass valve is automatically actuated shunting the flow of hydraulic fluid around the pump and a spring operates to counteract the separating force between the pinion and ring gear due to wind induced rotating force which produces torque on the pinion as a result of the back pressure in the motor and the shunted supply-return lines.

Abstract: A sea crane having a rotatable upper works mounted on a cylindrical pedestal with the upper works having a tiedown to the pedestal including an annular collar on the pedestal and a ring-like structure suspended from the upper works beneath the collar and mounted out of contact with both the collar and the pedestal. Tension links couple the bed of the upper works to the ring-like structure to prevent structural failure from bending the bed, or tilting and pulling the upper works either forward or backward from the pedestal.

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.

Abstract: A load handling device is disclosed having an improved swing drive assembly including a pivotally mounted swing drive pinion biased against a segmented ring gear by an actuator with a guide roller adjacent the pinion engaging a guide flange concentric with the ring gear to limit the maximum tooth engagement between the pinion and ring gear and thereby provide essentially constant backlash on the pinion gear regardless of eccentricities or other irregularities in the ring gear.