Mobile lift crane with variable position counterweight
CAFC
First Claim
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1. A method of operating a mobile lift crane, the lift crane comprising a carbody having moveable ground engaging members;
- a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members;
a boom pivotally mounted on a front portion of the rotating bed, with a hoist line extending therefrom;
a mast mounted at its first end on the rotating bed;
at least one linear actuation device; and
a moveable counterweight unit;
the method comprising;
a) performing a pick, move and set operation with a load wherein the moveable counterweight unit is moved toward and away from the front portion of the rotating bed by extending and retracting the linear actuation device during the pick, move and set operation to help counterbalance the load, but wherein the counterweight unit is never supported by the ground other than indirectly by the moveable ground engaging members on the carbody throughout the pick, move and set operation, and wherein the counterweight is moved a greater distance than a stroke of the linear actuation device that causes the counterweight to move.
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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.
61 Citations
24 Claims
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1. A method of operating a mobile lift crane, the lift crane comprising a carbody having moveable ground engaging members;
- a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members;
a boom pivotally mounted on a front portion of the rotating bed, with a hoist line extending therefrom;
a mast mounted at its first end on the rotating bed;
at least one linear actuation device; and
a moveable counterweight unit;
the method comprising;a) performing a pick, move and set operation with a load wherein the moveable counterweight unit is moved toward and away from the front portion of the rotating bed by extending and retracting the linear actuation device during the pick, move and set operation to help counterbalance the load, but wherein the counterweight unit is never supported by the ground other than indirectly by the moveable ground engaging members on the carbody throughout the pick, move and set operation, and wherein the counterweight is moved a greater distance than a stroke of the linear actuation device that causes the counterweight to move. - View Dependent Claims (2, 3, 4, 5, 6)
- a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members;
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7. A mobile lift crane comprising:
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a) a carbody having moveable ground engaging members; b) a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members; c) a boom pivotally mounted on a front portion of the rotating bed; d) a mast mounted at its first end on the rotating bed; e) a backhitch connected between the mast and a rear portion of the rotating bed; f) a moveable counterweight unit; g) at least one linear actuation device; and h) 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 being 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. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A mobile lift crane comprising:
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a) a carbody having moveable ground engaging members; b) a rotating bed rotatably connected about an axis of rotation to the carbody such that the rotating bed can swing with respect to the ground engaging members; c) a boom pivotally mounted on a front portion of the rotating bed; d) a moveable counterweight unit; and e) a counterweight movement structure connected between the rotating bed and the counterweight unit such that the counterweight unit may be moved to and held at both a forward position and a rearward position; f) wherein the counterweight movement structure comprises a rack and pinion assembly having housing and a rack, the rack having a rectangular cross section with first and second sides opposite one another and third and fourth sides opposite one another, and having teeth on the first side and second sides, and at least first and third pinion gears engaged with the teeth on the first side of the rack and second and fourth pinion gears engaged with the teeth on the second side of the rack, and wherein each pinion gear is driven by a separate hydraulic motor, and wherein the motor driving the first pinion gear is mounted on the housing adjacent an opposite side of the rack from the motor driving the third pinion gear, and wherein the motor driving the second pinion gear is mounted on the housing adjacent an opposite side of the rack from the motor driving the fourth pinion gear. - View Dependent Claims (19, 20, 21)
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22. A mobile lift crane comprising:
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a) a carbody having moveable ground engaging members; b) a rotating bed rotatably connected to the carbody such that the rotating bed can swing with respect to the ground engaging members; c) a boom pivotally mounted on a front portion of the rotating bed and including a load hoist line for handling a load; d) a moveable counterweight unit; e) a counterweight movement structure connected between the rotating bed and the counterweight unit such that the counterweight unit may be moved to and held at both a forward position and a rearward position; and f) a counterweight support structure attached to the counterweight unit including at least two counterweight support structure ground engaging members that can provide support to the counterweight unit in the event of a sudden release of the load, the support structure comprising a telescoping structure connected to and between the counterweight support structure ground engaging members such that the lateral distance between the counterweight support structure ground engaging members can be adjusted between at least a first and second position; and
wherein, when the counterweight unit is in its forward position, the counterweight support structure ground engaging members will interfere with a swing operation of the crane in their first position, but will not interfere with a swing operation of the crane in their second position. - View Dependent Claims (23, 24)
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Specification
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Litigation Data
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Current AssigneeGrove US L L C
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Original AssigneeManitowoc Cranes LLC (The Manitowoc Company, Inc.)
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InventorsPorubcansky, Kenneth J., Lanning, John M., Pech, David J., Pleuss, Alan E.
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Primary Examiner(s)Brahan; Thomas J.
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Application NumberUS12/023,902Publication NumberTime in Patent Office1,244 DaysField of Search212/178, 212/270, 212/296US Class Current212/296CPC Class CodesB66C 23/76 and movable to take account...
