Abstract: The invention relates to a tower crane having a slewing platform, an adjustable boom articulated in a derricking manner on the slewing platform and counter-ballast mounted on the slewing platform, characterized in that an adjusting mechanism is provided that permits a positional change to the counter-ballast independent of the luffing angle of the adjustable boom.

Abstract: The invention relates to a method for operating multiple cranes (1, 2), the movements of which are monitored for imminent collisions by anti-collision devices of the cranes, and to cranes comprising at least one movement device for moving a crane element, a control unit (13) for actuating the movement device, and an anti-collision device (17, 18) for monitoring the crane movements of the crane element for possible collisions with another crane.

Abstract: The invention relates to a method of weathervaning a work machine in out-of-operation mode, in particular of weathervaning a revolving crane/revolving tower crane or a concrete spreader mast, wherein the work machine comprises at least one slewing part that is rotatable about a substantially vertical axis by means of a slewing gear, and wherein in a first step one or more wind data are measured by means of a measurement system arranged at the work machine; an optimum position of the slewing part is determined for an optimum weathervaning in dependence on the detected wind data; and the slewing gear drive is subsequently correspondingly actuated to bring the slewing part into the determined position.

Abstract: The present invention relates to a method for weathervaning of a crane which has a boom which can rotate about a vertical axis, a slewing gear motor and a slewing gear service brake for securing the boom in a rotational position with a securing torque in the crane mode, wherein in the case of a crane which has been out-of-operation, the boom is braked against rotation with an out-of-operation mode braking torque which is less than said securing torque in the crane mode. In this respect, the invention also relates to such a crane itself, in particular in the form of a revolving tower crane. In accordance with the invention, the out-of-operation mode braking torque is kept at least approximately constant over the range of the speed of rotation and over the range of the angle of rotation of the boom.

Abstract: The invention relates to a method of weathervaning a work machine in out-of-operation mode, in particular of weathervaning a revolving crane/revolving tower crane or a concrete spreader mast, wherein the work machine comprises at least one slewing part that is rotatable about a substantially vertical axis by means of a slewing gear, and wherein in a first step one or more wind data are measured by means of a measurement system arranged at the work machine; an optimum position of the slewing part is determined for an optimum weathervaning in dependence on the detected wind data; and the slewing gear drive is subsequently correspondingly actuated to bring the slewing part into the determined position

Abstract: The invention relates to a method for operating multiple cranes (1, 2), the movements of which are monitored for imminent collisions by anti-collision devices of the cranes, and to cranes comprising at least one movement device for moving a crane element, a control unit (13) for actuating the movement device, and an anti-collision device (17, 18) for monitoring the crane movements of the crane element for possible collisions with another crane.

Abstract: The invention relates to a tower crane comprising a tower of at least one tower element, in particular a lattice piece, and a structural guying device having at least one guying rod for the horizontal anchorage of the tower at a structure. In accordance with the invention, the tower has a vertically adjustable guide frame, wherein at least one positioning rope is adjustably fastened to the guide frame. The invention furthermore relates to a method of mounting a wind turbine rotor blade.

Abstract: The invention relates to a tower crane comprising a tower of at least one tower element, in particular a lattice piece, and a structural guying device having at least one guying rod for the horizontal anchorage of the tower at a structure. In accordance with the invention, the tower has a vertically adjustable guide frame, wherein at least one positioning rope is adjustably fastened to the guide frame. The invention furthermore relates to a method of mounting a wind turbine rotor blade.

Abstract: The device enables a switch from the pulley blocks being rigged with one strand to the pulley blocks being rigged with two strands and vice versa. The jib tip has a pulley moveable along its axle between a central position, when the blocks are rigged with one strand, and a lateral position, when the blocks are rigged with two strands. The lifting block, with housing of symmetric shape, comprises a pulley and retractable guide means for the lifting cable. When the blocks are rigged for two strands, the end of the cable is connected to a point of attachment situated on the jib tip, on the opposite side to the lateral position of the pulley. When the blocks are rigged with one strand, the end of the cable is connected to a point of attachment situated on the pulley block. This device for changing the rigging of the blocks applies mainly to luffing cranes.

Abstract: The device enables a switch from the pulley blocks being rigged with one strand to the pulley blocks being rigged with two strands and vice versa. The jib tip has a pulley moveable along its axle between a central position, when the blocks are rigged with one strand, and a lateral position, when the blocks are rigged with two strands. The lifting block, with housing of symmetric shape, comprises a pulley and retractable guide means for the lifting cable. When the blocks are rigged for two strands, the end of the cable is connected to a point of attachment situated on the jib tip, on the opposite side to the lateral position of the pulley. When the blocks are rigged with one strand, the end of the cable is connected to a point of attachment situated on the pulley block. This device for changing the rigging of the blocks applies mainly to luffing cranes.