Patent ID: 6568547
Filing Date: 2003-05-27
Classification: B66C

Abstract:
A crane, comprising: a base structure; a revolving superstructure mounted on the base structure; a boom and a mast hinged to the superstructure; guying of adjustable length arranged to connect a tip of the mast on one side to a head of the boom; a counterweight; further guying arranged to connect another side of the mast to the counterweight, without provision of a separate superstructure counterweight; a frame arranged so as to permit a distance between the counterweight and the superstructure to be continuously variable within a fixed range, the frame being movable in a vertical plane, mounted on the superstructure and connected to the superstructure in a gravity-actuated nonpositive manner, the frame including an axially stationary frame part; means connected to the frame for directing a resultant of a counterweight force which acts in a direction of gravity and guying force produced by a suspended load into the superstructure, the means for directing the resultant force including at least one vertically acting piston-cylinder unit hinged to the stationary frame part and hinged to the superstructure, the stationary frame part being connected to the superstructure, the frame further including an axially movable frame part which is movable along a longitudinal axis of the stationary frame part; and a load-bearing structure for the counterweight, the axially stationary frame part being arranged to extend beyond a hinge point of the vertically acting piston-cylinder unit so as to have an overhanging area connectable to the load-bearing structure for the counterweight, an end area of the axially movable frame part is connectable to the load-bearing structure carrying the counterweight.