Abstract: A crawler crane having identical left and right crawler assemblies. The left and right crawler assemblies each comprise an identical crawler drive assembly to power the individual crawlers. Each crawler drive assembly comprises a hydraulic drive motor connected to the crawler. Both crawler drive assemblies utilize identical mounting configurations for connecting the hydraulic drive motor to the frame of the crawler.

Abstract: A control system for a liftcrane that utilizes a closed loop hydraulic system that utilizes feed back and feed forward control architecture to provide responsiveness normally associated with systems that do not require feedback.

Abstract: A drum drive assembly for cranes which use a load hoist line reeled onto a load hoist line drum to lift loads allows the load hoist line drum to be disconnected from the drum drive motor to permit the load hoist line drum to rotate independent of the drum drive motor. The drum drive assembly comprises one or more motors for rotating the load hoist line drum to either pay out or reel in the load hoist line; a brake for slowing, stopping or preventing the rotation of the load hoist line drum; and a jaw clutch which may be disengaged to permit the load hoist line drum to rotate independently of the motor.

Abstract: A crane has a boom with a rotatable boom section connection system. The crane has an upper works rotatably mounted on a lower works, the upper works including a load hoist winch. The boom comprises at least a first and second boom section each with a longitudinal axis and a first and second end, the second end of the first section being coupled to the first end of the second section. At least one male connector on the second end of the first section is coupled to a female connector on the first end of the second section. The male connector comprises a base and a protrusion, the base and protrusion each have an extension in a direction generally perpendicular to the longitudinal axis of the first boom section. The extensions and protrusion define a socket. The female connector comprises two protrusions spaced apart at a distance such that the protrusion of the male connector fits between the two protrusions.

Abstract: An apparatus for powering the crawlers of a crawler vehicle. The apparatus comprises one or more hydraulic drive motors mounted on the vehicle, car body, a track drive gear box mounted on the crawler, and one or more mechanical drive shafts connected between the hydraulic drive motors and the track drive gear box to transmit power from the drive motors to the track drive gear box. The mechanical drive shafts are disconnectable from between the hydraulic drive motors and the track, drive gear box so as to permit the disassembly and removal of the crawlers from the car body.

Abstract: A crane having an upper works rotatably mounted on a lower works and a boom pivotally mounted on the upper works, wherein the crane further comprises an apparatus and method for lifting, positioning, and assembling a counter weight to the upper works. The apparatus and method includes pivotally connecting a counter weight pivot frame between the counter weight and the upper works and lifting the counter weight into position with the hydraulic boom hoist cylinder. The crane further comprises a boom parking device.

Abstract: A crane having an upper works rotatably mounted on a lower works, a boom pivotally mounted on the upper works, and a hydraulic boom hoist cylinder to control the angle of the boom. The crane further comprises a mast and a hydraulic cylinder pivotally connected to the upper works. The connection of the mast to the upper works is at a location separate from, and at an elevation below, the elevation of the connection of the hydraulic cylinder to the upper works. The hydraulic cylinder is pivotally connected to the mast and pendently connected to the boom.

Abstract: A swing lock mechanism for machines having an upper works rotatably mounted on a lower works by a swing bearing is connected to the drive shaft of a swing bearing drive assembly and comprises a swing lock plate, an annular pin support, and a plurality of locking pins. The swing lock plate is affixed to the drive shaft and has at least one hole disposed about the axis of the drive shaft. The annular pin support is fixed against rotation relative to the drive shaft is disposed about the axis of the drive shaft. The locking pins are supported by the annular pin support and are also disposed about the axis of the drive shaft. The locking pins are arranged in such a manner so as at least one pin may engage a hole in the swing lock plate irrespective of the angular orientation of the swing lock plate relative to the annular pin support.

Abstract: A ring-supported lift crane is provided with a counterweight handling system to facilitate repositioning of the crane. The ring-supported crane includes a ring, a crane upper works and a crane lower works, a boom supported on rollers on the ring and a counterweight assembly also supported on rollers on the ring. The counterweight assembly preferably includes a counterweight carrier on which at least one stack of counterweight boxes or units are placed. A counterweight holder is interposed between the at least one stack of counterweight units and the counterweight carrier with a friction reduction device, such as rollers or slider pads, interposed between the counterweight holder and the counterweight carrier. When the ring-supported crane is to be repositioned for a second lift at a construction site, the counterweight holder with the stack of counterweight units is moved off of the counterweight carrier onto a separate counterweight support member, which may be mobile or stationary.

Abstract: A crane boom and luffing jib assembly have an offsetting link to allow the luffing jib to fold back and under the main boom for assembly of the boom and luffing jib assembly on a construction site where the entire length of the boom and luffing jib cannot be laid out during assembly.