DERRICKING CYLINDER LOAD REDUCING DEVICE FOR MOBILE CRANE

摘要

PROBLEM TO BE SOLVED: To provide a derricking cylinder load reducing device for a mobile crane that can reduce the load acting on a derricking cylinder and is easily variable in the number of wire windings for a load lifting hook. SOLUTION: A mobile crane has a telescopic boom supported pivotally so as to be freely raised and laid on a revolving base of the mobile crane, and a derricking cylinder interposed between the telescopic boom and the revolving base. A base boom tip of the telescopic boom has an upper auxiliary sheave and the revolving base top has a lower auxiliary sheave. A wire rope unwound from and rewound about a winch mounted on the revolving base is entrained between the upper auxiliary sheave and the lower auxiliary sheave before being suspended via an upper and a lower sheave arranged on the boom head of the telescopic boom and furthermore entrained between the lower boom head sheave and a load lifting hook, and the wire rope end is locked to the boom head or the load lifting hook.