ELECTROHYDRAULIC CONTROL SYSTEM OF SELF-PROPELLED BOOM CRANE Russian patent published in 1997 - IPC

FIELD: mechanical engineering; hoisting and transportation facilities; hydraulic control systems. SUBSTANCE: two-position distributor 21 is placed in hydraulic control system in device for unloading the system in case of operation of crane safeguards. Two-position distributor 21 is made in the form of electromagnet and is installed in control main line 23 before control columns 19, 20 for placing the following devices in communication in one of its positions, with tank 46 through throttling device 24: crane operation inhibit relay, interlock relay, two-position distributor cut-in relay and overload safeguard which provides shaping of crane motion enable and inhibit signals depending on signals applied to its inputs and closing and opening of contacts of pressure relays 25-32 installed in control lines 11-18. If crane lifting capacity values are exceeded during the operation, signals from corresponding sensors and pressure relays are converted into inhibit signal at overload safeguard output and crane operation is stopped. To bring the crane out of overload condition, control system provides operations aimed at decreasing the load moment. EFFECT: improved operation reliability and safety. 2 dwg