Hydraulic overload safety arrangement for a lifting appliance

摘要

A hydraulic overload safety arrangement (10) for a jib (11), actuated by a hydraulic cylinder (18), of a loading crane is proposed in which a pump (37) can be switched off via a relief valve (49) in order to limit the load moment, the change in the working position increasing the load moment being automatically taken into account as a function of the the position of the controlled jib part (15) relative to the horizontal (21). Arranged on the jib part (15) are hydromechanical load sensors (58) which, in a control-line system (72), lie in series with a safety valve (54) piloting the relief valve (49). The position sensors (58) control the pressure signals allocated to the relief valve (49) in such a way that pivoting movements reducing the load moment can be carried out irrespective of the positive or negative setting angle of the jib part (15), whereas the pump (37) is relieved in working positions increasing the load moment. <IMAGE>