HYDRAULIC DRIVE OF SINGLE-BUCKET FRONT-END LOADER Russian patent published in 1997 - IPC

FIELD: hydraulic drives of load-handling equipment. SUBSTANCE: hydraulic drive has pump-motors of loading attachment, hydraulic control manifold connected by hydraulic lines with working spaces of boom and bucket hydraulic cylinders, two four-way three-position electrically-operated control valves which are interconnected through four-way two-position control valve. Installed in suction line of one of pump-motors is feed-up valve. Similar valve is installed in suction line of other pump-motor. Outlet of this pump-motor is connected through four-line two-position control valve with hydraulic steering unit. Hydraulic pressure line of first pump-motor is connected with hydraulic suction line of second pump-motor by means of pilot-controlled hydraulic check valve. Spaces of aforesaid check valve are connected with outlet of pump-motors. EFFECT: high efficiency. 3 dwg