Abstract: A lift crane includes a carbody and movable ground engaging members mounted on the carbody. A rotating bed is rotatably connected to the carbody and includes a counterweight support frame including a rack coupled directly to a lower surface of the rotating bed. A boom is pivotally mounted to the rotating bed. A counterweight unit includes a trolley, the counterweight unit being in a movable relationship with respect to the rotating bed. A counterweight unit movement device is configured to move the counterweight unit toward and away from the boom. Other embodiments include a counterweight support beam movably connected to the rotating bed, the counterweight support beam including another rack coupled to a lower surface of the counterweight support beam. A counterweight support beam movement device is connected between the counterweight support beam and the counterweight support frame.

Abstract: A connector for a column segment, such as a boom segment, of a crane includes n extensions, where n is a positive integer. Each extension has a first base and an aperture extends through the extension from a first side to a second side. The first connector also includes at least (n+y) plates, where y is selected from the group consisting of (?1, +1) such that the sum of (n+y) is a positive integer. The plate or plates are positioned in and coupled to the extensions in an alternating arrangement. Each plate includes a plate base aligned substantially in a plane with the first base of the extension to form a first connector mounting surface. A plurality of welds couple the plates to the extensions and the fabricated connector is then welded to the column segment. At least one extension is formed of steel having a grain structure elongated in a direction of rolling that is substantially perpendicular to the first base.

Abstract: A mobile lift crane includes a carbody; a rotating bed; a boom; a moveable counterweight unit; at least one linear actuation device; and at least one arm pivotally connected at a first end to the rotating bed and at a second end to the linear actuation device. The arm and linear actuation device are connected between the rotating bed and the counterweight unit such that extension and retraction of the linear actuation device changes the position of the counterweight unit compared to the rotating bed. In one method of operation, the counterweight unit is never supported by the ground during crane pick, move and set operations other than indirectly by the ground engaging members on the carbody.

Abstract: A mobile lift crane includes a carbody; a rotating bed; a boom; and a moveable counterweight unit. The crane is configured such that the counterweight unit is never supported by the ground other than indirectly by moveable ground engaging members on the carbody throughout a pick, move and set operation. In a first aspect, the crane is operable to move the counterweight unit to at least a first position in front of a fixed rearmost portion of the rotating bed and a second position behind the fixed rearmost portion of the rotating bed. In a second aspect, the crane also includes a first linear actuation device operable to move the counterweight unit toward and away from the front portion of the rotating bed by extending and retracting the linear actuation device. The counterweight unit may be moved a greater distance than a stroke of the first linear actuation device.

Abstract: A connector for a column segment, such as a boom segment, of a crane includes n extensions, where n is a positive integer. Each extension has a first base and an aperture extends through the extension from a first side to a second side. The first connector also includes at least (n+y) plates, where y is selected from the group consisting of (?1, +1) such that the sum of (n+y) is a positive integer. The plate or plates are positioned in and coupled to the extensions in an alternating arrangement. Each plate includes a plate base aligned substantially in a plane with the first base of the extension to form a first connector mounting surface. A plurality of welds couple the plates to the extensions and the fabricated connector is then welded to the column segment. At least one extension is formed of steel having a grain structure elongated in a direction of rolling that is substantially perpendicular to the first base.

Abstract: A lift crane includes a carbody; ground engaging members elevating the carbody off the ground; a rotating bed rotatably connected to the carbody; a boom pivotally mounted at a first end to the rotating bed with a load hoist line extending adjacent a second end of the boom; a boom hoist mechanism that can be used to change the angle of the boom relative to the rotating bed during crane operation; and a boom raising assist structure connected to the boom. The boom raising assist structure preferably includes at least one ground engaging member in contact with the ground; and a boom elevating member extending between the assist structure ground engaging member and the boom. The boom elevating member supports at least a part of the weight of the boom.

Abstract: A mobile lift crane includes a carbody; a rotating bed; a boom; a moveable counterweight unit; at least one linear actuation device; and at least one arm pivotally connected at a first end to the rotating bed and at a second end to the linear actuation device. The arm and linear actuation device are connected between the rotating bed and the counterweight unit such that extension and retraction of the linear actuation device changes the position of the counterweight unit compared to the rotating bed. In one method of operation, the counterweight unit is never supported by the ground during crane pick, move and set operations other than indirectly by the ground engaging members on the carbody.

Abstract: A mobile lift crane includes a carbody; a rotating bed; a boom; a moveable counterweight unit; at least one linear actuation device; and at least one arm pivotally connected at a first end to the rotating bed and at a second end to the linear actuation device. The arm and linear actuation device are connected between the rotating bed and the counterweight unit such that extension and retraction of the linear actuation device changes the position of the counterweight unit compared to the rotating bed.

Abstract: A mobile lift crane includes a carbody; a rotating bed; a boom; and a moveable counterweight unit. The crane is configured such that the counterweight unit is never supported by the ground other than indirectly by moveable ground engaging members on the carbody throughout a pick, move and set operation. In a first aspect, the crane is operable to move the counterweight unit to at least a first position in front of a fixed rearmost portion of the rotating bed and a second position behind the fixed rearmost portion of the rotating bed. In a second aspect, the crane also includes a first linear actuation device operable to move the counterweight unit toward and away from the front portion of the rotating bed by extending and retracting the linear actuation device. The counterweight unit may be moved a greater distance than a stroke of the first linear actuation device.

Abstract: A crawler has a track tensioning system. The crawler includes a crawler frame having a bottom; at least one drive tumbler supported on the frame; a track made of a plurality of connected track shoes and is wrapped around the drive tumbler so that a plurality of the shoes are in contact with the drive tumbler. The track tensioning system, mounted to the frame, includes a roller engaging the inside surface of the track; and a roller positioning structure attached to the frame that can raise the roller relative to the bottom of the frame to thereby increase the tension of the track.

Abstract: A mobile lift crane includes a carbody made from two side members and two end cross members connected to each other with a carbody connection that can be disconnected such that the side members and end cross members can be individually transported between job sites and reassembled at a new job site. Preferably the two side members are interchangeable with each other when making the carbody, and the two end cross members are also interchangeable with each other. Further, each of the side members and end cross members preferably has a section of a roller path and section of a ring gear attached to them while being transported and assembled.

Abstract: A method of connecting sections of a crane suspension assembly together includes attaching a frame to a member of a first section; connecting a tension member between the frame and a connector used in the assembly; moving the tension member so that the connector pivots about a pin to a position where a second hole in the connector is in alignment with a hole in a second section member; putting a second pin through the hole in the connector and the hole through the second section member; and disconnecting the tension member from the connector. The method may also include attaching a frame with a winch to a section of the crane suspension assembly; connecting a line from the winch to the connector; activating the winch to move the connector so that it pivots about a pivot axis; and securing the connector in its second position.

Abstract: A combination of a drive tumbler and a track includes a track made of a plurality of connected track shoes and a plurality of driven surfaces. The track is wrapped around the drive tumbler so that a plurality of the shoes are in contact with the drive tumbler. The drive tumbler has a plurality of drive surfaces and a circumferential rim surface that includes a plurality of shoe contact surfaces that each contact the inside surface of one of the track shoes that are in contact with the tumbler. The shoe contact surface has a shape such that a line normal to the tangent of the shoe contact surface does not pass through the axis of rotation of the drive tumbler, thereby allowing the shoe contact surfaces on the rim of the drive tumbler to transmit a tractive force to the track. A preferred drive tumbler comprises a center hub and a plurality of individual tooth members connected to the center hub by welds.

Abstract: A mobile lift crane includes a carbody; a rotating bed; a boom; a moveable counterweight unit; at least one linear actuation device; and at least one arm pivotally connected at a first end to the rotating bed and at a second end to the linear actuation device. The arm and linear actuation device are connected between the rotating bed and the counterweight unit such that extension and retraction of the linear actuation device changes the position of the counterweight unit compared to the rotating bed. In one method of operation, the counterweight is never supported by the ground during crane pick, move and set operations other than indirectly by the ground engaging members on the carbody. The linear actuation device can include at least one rack and pinion assembly or hydraulic cylinder.

Abstract: A mobile lift crane includes a carbody, a rotating bed, a boom, a moveable counterweight unit, at least one linear actuation device and at least one arm pivotally connected at a first end to the rotating bed and at a second end to the linear actuation device. The arm and linear actuation device are connected between the rotating bed and the counterweight unit such that extension and retraction of the linear actuation device changes the position of the counterweight unit. In one method of operation, the counterweight is never supported by the ground during crane pick, move and set operations other than indirectly by the ground engaging members on the carbody. One embodiment includes a counterweight movement structure having a rectangular rack with at least first and third pinion gears engaged with teeth on one side and second and fourth pinion gears engaged with teeth on the opposing side.

Abstract: A lift crane includes a carbody; a rotating bed comprising a counterweight support frame; a boom; a counterweight unit supported on the counterweight support frame in a moveable relationship with respect to the counterweight support frame; and a counterweight unit movement device connected between the rotating bed and the counterweight unit to move the counterweight unit toward and away from the boom. The crane is configured such that during crane operation, the moment generated by the counterweight unit acts on the rotating bed predominantly through the counterweight support frame. Alternatively, the crane can include a mast. In some embodiments the same basic crane is configured to be set-up with two different counterweight options, i) a counterweight unit directly supported on the counterweight support frame and ii) a counterweight support beam moveably connected to the remainder of the rotating bed and a counterweight unit supported on the counterweight support beam.

Abstract: A lift crane includes a carbody; ground engaging members elevating the carbody off the ground; a rotating bed rotatably connected to the carbody; a boom pivotally mounted at a first end to the rotating bed with a load hoist line extending adjacent a second end of the boom; a boom hoist mechanism that can be used to change the angle of the boom relative to the rotating bed during crane operation; and a boom raising assist structure connected to the boom. The boom raising assist structure preferably includes at least one ground engaging member in contact with the ground; and a boom elevating member extending between the assist structure ground engaging member and the boom. The boom elevating member supports at least a part of the weight of the boom.

Abstract: A mobile lift crane includes a central crane unit, a boom unit and a counterweight unit. The central crane unit has a carbody, moveable ground engaging members and a rotating bed mounted to the ground engaging members with a rotatable connection such that the rotating bed can swing with respect to the ground engaging members. The boom unit has a support member, at least one moveable ground engaging member, and a boom pivotally mounted on the support member. The counterweight unit has counterweight on a support member. Rigging connects the boom and counterweight unit such that a load lifted by the boom can be counterbalanced by the counterweight. The boom unit and counterweight unit are connected to the central crane unit by structural members that carry compressive loads and maintain the boom unit, the rotating bed and the counterweight unit in lateral alignment with each other, but allow relative vertical movement between the boom unit, the rotating bed and the counterweight unit.

Abstract: A mobile lift crane includes a central crane unit, a boom unit and a counterweight unit. The central crane unit has a carbody, moveable ground engaging members and a rotating bed mounted to the ground engaging members with a rotatable connection such that the rotating bed can swing with respect to the ground engaging members. The boom unit has a support member, at least one moveable ground engaging member, and a boom pivotally mounted on the support member. The counterweight unit has counterweight on a support member. Rigging connects the boom and counterweight unit such that a load lifted by the boom can be counterbalanced by the counterweight. The boom unit and counterweight unit are connected to the central crane unit by structural members that carry compressive loads and maintain the boom unit, the rotating bed and the counterweight unit in lateral alignment with each other, but allow relative vertical movement between the boom unit, the rotating bed and the counterweight unit.

Abstract: A mobile lift crane includes a carbody made from two side members and two end cross members connected to each other with a carbody connection that can be disconnected such that the side members and end cross members can be individually transported between job sites and reassembled at a new job site. Preferably the two side members are interchangeable with each other when making the carbody, and the two end cross members are also interchangeable with each other. Further, each of the side members and end cross members preferably has a section of a roller path and section of a ring gear attached to them while being transported and assembled.