Load hook control device for a crane

#The present invention relates to a crane, in particular to a lattice mast crane; having a bottom hook block with a load suspension means, in particular a load hook.

#When raising large loads at great heights, the robustness of the hoisting system toward external influences, in particular attacking wind forces, plays a decisive role. The large loads to be raised have a large surface and consequently offer a large exposed surface to the wind forces. The engaging forces result in a swaying of the load or an oscillating of the hook, which can have the consequence of an unstable hoist system. For safety reasons, limits are defined for maximum permitted wind speeds up to which a planned hoist may be carried out at all.

#The robustness of the system with respect to the attacking wind forces is also a decisive criterion in the installation of the suspended load at a great height since an alignment of the load at the installation height which is as precise and as stable as possible is desirable here.

#Further features, details and advantages of the invention will be explained in more detail with reference to an embodiment shown in the drawings. There are shown:

#FIG. 1: a side view of a crane having a lattice boom in an aligned position with a bottom hook block in accordance with the invention;

#FIG. 2: two detail views of the bottom hook block in accordance with the invention;

#The lattice mast crane 1 shown in FIG. 1 has, in a known manner, a two-part boom 11 which can be luffed about a horizontally lying luffing axis with the aid of a luffing mechanism. The reference numerals used in the following relate exclusively to FIGS. 1 to 3. A rearwardly directed derrick boom is installed behind the main boom 11. The guying of the boom 11 is realized with the aid of the guying rods 2.

#At least one hoist rope 12 is guided over one or more pulley blocks of the roller head 10 over the tip of the boom 11 and is reeved several times into the pulley blocks 50 of the bottom hook block 51. To be able to better take up the forces caused by the load and its alignment about a vertical axis, the roller head 10 is configured as widened at the tip of the boom 11. In accordance with the design of the roller head 10, the pulley blocks 50 of the bottom hook block 51 are also accordingly arranged spaced apart from one another so that an almost perpendicular extent of the hoist rope 12 is ensured. A configuration of the crane 1 in accordance with the invention in multirope operation is generally also conceivable. There is a large resistance per se to a rotation of the load and of the bottom hook block 51 with respect to the roller head due to the large spacing of the two outer pulley blocks 50 of the bottom hook block 51.

#For the further stabilizing of the position of the bottom hook block 51 and of the load or for the realizing of an actively adjustable positioning of the bottom hook block 51, this is equipped in accordance with the invention with the two control winches 52.