Lift crane with moveable counterweight

A lift crane comprising:

• a) a carbody;
• b) ground engaging members elevating the carbody off the ground;
• c) a rotating bed rotatably connected to the carbody about an axis of rotation, the rotating bed having a fixed rearmost portion;
• d) a boom pivotally mounted on the front portion of the rotating bed and including a load hoist line for handling a load;
• e) a mast connected to the rotating bed, and adjustable-length boom hoist rigging connected between the mast and the boom that allows the angle of the boom relative to the plane of rotation of the rotating bed to be changed;
• f) a counterweight support beam moveably connected to the rotating bed;
• g) a counterweight support beam movement device connected between the counterweight support beam and the rotating bed such that the counterweight support beam can be moved with respect to the length of the rotating bed away from the rotational connection of the rotating bed and the carbody, and extend rearwardly of the fixed rearmost portion of the rotating bed;
• h) a tension member connected between the mast and the counterweight support beam;
• i) a counterweight unit supported on the counterweight support beam in a moveable relationship with respect to the counterweight support beam;
• and
• j) a counterweight unit movement device connected between the counterweight support beam and the counterweight unit so as to be able to move the counterweight unit toward and away from the boom;
• k) wherein the counterweight unit may be moved to and held at a position in front of the top of the mast and moved to and held at a position rearward of the top of the mast.

A mobile lift crane comprising, when set up, a carbody having moveable ground engaging members;

• a rotating bed rotatably connected to the carbody such that the rotating bed can swing about an axis of rotation with respect to the ground engaging members;
• and a boom pivotally mounted on a front portion of the rotating bed, with a hoist line extending there from;
• wherein the crane is configured to be set up with two different counterweight set-up configuration options:
• i) a first counterweight set-up configuration option wherein a first counterweight movement system can move a first counterweight unit between a first position and a second position, wherein the first position is a position in which the first counterweight unit is as near as possible to the axis of rotation for the first counterweight set-up configuration option, constituting a first distance from the axis of rotation, and where the second position is a position in which the first counterweight unit is as far as possible from the axis of rotation for the first counterweight set-up configuration option, constituting a second distance from the axis of rotation;
• and ii) a second counterweight set-up configuration option wherein a second counterweight movement system can move a second counterweight unit between a third position and a fourth position, where the third position is a position in which the second counterweight unit is as near as possible to the axis of rotation for the second counterweight set-up configuration option, constituting a third distance from the axis of rotation, and where the fourth position is a position in which the second counterweight unit is as far as possible from the axis of rotation in the second counterweight set-up configuration option, constituting a fourth distance from the axis of rotation;
• and further wherein the fourth distance is greater than the second distance, and wherein the difference between the third and fourth distances is greater than the difference between the first and second distances.

A lift crane comprising:

• a) a carbody having moveable ground engaging members mounted on the carbody allowing the crane to move over the ground;
• 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 moveable ground engaging members;
• c) a boom pivotally mounted on the front portion of the rotating bed and including a load hoist line for handling a load;
• d) a mast pivotally mounted on the rotating bed at a first end;
• e) a boom hoist system comprising pendants connected between the mast and the boom, the boom and mast being connected together with a fixed length of rigging between the boom and the mast, and a boom hoist system mounted between the mast and the rotating bed, the boom hoist system allowing the angle of the boom relative to the plane of rotation of the rotating bed to be changed;
• f) a moveable counterweight unit supported on the rotating bed;
• and
• g) a counterweight movement system connected between the rotating bed and the counterweight unit so as to be able to move the counterweight unit toward and away from the boom.