A level-controllable crawler crane includes two crawler supports with rotating crawlers, which crawler supports are connected by a transversal bridge. A superstructure of the crawler crane includes a crane jib pivotable about a vertical axis and connected to the transversal bridge. A pivotable articulation connects the transversal bridge to the crane superstructure. At least one of the crawler supports is connected to the transversal bridge by a double link having a lower and an upper link. The lower link is articulated on the crawler support by a crawler support lower pivotable axis and on the transversal bridge by a transversal bridge lower pivotable axis. The upper link is articulated on the crawler support by a crawler support upper pivotable axis and on the transversal bridge by a transversal bridge upper pivotable axis. A drive pivots the links about the pivotable axis associated therewith.

The invention relates to a method of operating a crane having a luffable crane boom and having a trolley travelable at the crane boom, wherein the crane can be operated in a luffing mode, on the one hand, and in a trolley mode, on the other hand. In accordance with the invention, a switch is made between a luffing mode and a trolley mode by varying the hoist rope reeving. The invention further relates to such a crane for carrying out the method.

The invention relates to a method of operating a crane having a luffable crane boom and having a trolley travelable at the crane boom, wherein the crane can be operated in a luffing mode, on the one hand, and in a trolley mode, on the other hand. In accordance with the invention, a switch is made between a luffing mode and a trolley mode by varying the hoist rope reeving. The invention further relates to such a crane for carrying out the method.

A crane for lifting and transporting loads includes a base frame, for transferring the loads of the crane onto a support surface by a plurality of wheels having two steering wheels; and a steering system. The steering system includes a linear steering actuator, which is hinged, on one side, to the base frame and, on the other side, to a bar having two ends. Each end of the bar is hinged to a respective rotary element around a respective hinging axis. Each rotary element rotates around a respective rotation axis and is constrained in rotation to the respective steering wheel to steer it.

A crane for lifting and transporting loads includes a base frame, for transferring the loads of the crane onto a support surface by a plurality of wheels having two steering wheels; and a steering system. The steering system includes a linear steering actuator, which is hinged, on one side, to the base frame and, on the other side, to a bar having two ends. Each end of the bar is hinged to a respective rotary element around a respective hinging axis. Each rotary element rotates around a respective rotation axis and is constrained in rotation to the respective steering wheel to steer it.

An excavator (1) having a lifting device (2) for lifting a pallet comprising a chassis (3) having a boom (4) mounted thereon and a dipper arm (5) pivotally coupled to a distal end of said boom to which an implement, such as a bucket, may be attached, said lifting device comprising a mast (12) upon which is slideably mounted a carriage (20), a pair of spaced tines (21, 22) being provided on said carriage for supporting a pallet thereon, wherein said mast is mounted on said dipper arm of said excavator to be arranged in a vertical or substantially vertical operative orientation such that, in use, said carriage can be moved between lowered and raised positions on said mast when the mast is mounted on said boom, wherein at least one ground engaging load bearing member (28, 29) is provided at a lower end of said mast.

A vehicle crane system includes a vehicle crane having a detachable attachment part, in particular a main jib, and an attachment part transporting unit which is designed to receive the attachment part when the latter is detached from the vehicle crane and comprises a mobile transporting device for transporting the attachment part. To remove and mount the attachment part of the vehicle crane and to transport it, the transporting device is equipped with at least one loading arm, the free supporting end of which is provided for at least indirect temporary coupling to an attachment part which is to be received or is already received. The loading arm is mounted pivotably on the transporting device such that an attachment part to be loaded or unloaded can be moved down onto the transporting device or from the transporting device.

A method for securing an angular position of a crane jib displaceable in lifting and in lowering by a winch integrating a motor driving a drum on which is wound a rope and secured to a platen provided with arcuate oblong locking holes, the method including measuring a speed parameter representative of an angular speed of the jib, controlling the motor to displace the jib with a limitation of the speed parameter to a first maximum value and a limitation of a motor torque to a first limit value, until reaching an angular position in which a lock is aligned with and locked into the locking hole, and controlling the motor to displace the jib in lowering with a limitation of the speed parameter to a second maximum value and a limitation of the motor torque to a second limit value, until the speed parameter is null for a predetermined time period to stop the motor.

A height adjustment assistance device includes an initial state determination part for determining whether a suspended cargo has been lifted from a ground at a start of lifting work, a height detection part for detecting a height of a counterweight from the ground, a storage part for storing an initial height, a calculation part for calculating a target value for correcting the height of the counterweight from the ground based on the initial height and a post-work height, a notification part for notifying an operator of information regarding the target value, and a length adjustment device for adjusting a length of a hanging member by operating in a manner to change the length of the hanging member extending from a tip of a mast to the counterweight.

A height adjustment assistance device includes an initial state determination part for determining whether a suspended cargo has been lifted from a ground at a start of lifting work, a height detection part for detecting a height of a counterweight from the ground, a storage part for storing an initial height, a calculation part for calculating a target value for correcting the height of the counterweight from the ground based on the initial height and a post-work height, a notification part for notifying an operator of information regarding the target value, and a length adjustment device for adjusting a length of a hanging member by operating in a manner to change the length of the hanging member extending from a tip of a mast to the counterweight.