HYDRAULIC DRIVE Russian patent published in 1995 - IPC

FIELD: mechanical engineering. SUBSTANCE: line of a distributing unit is connected with a power source and the output line of the unit is connected with the drain. Two actuating lines are in communication with above-piston and under-piston spaces of the hydraulic cylinder through corresponding hydraulic lines provided with controlled check valves. The control spaces of the valves are in communication with the third actuating line of the distributing unit. The unit is constructed as a four-position five-line distributor. At two working positions, the inlet and outlet lines are connected with corresponding two first actuating lines. and the third actuating line is connected with the outlet line. At the third working position, the first two actuating lines are connected with the outlet line and the third actuating line is connected with the inlet line. At the neutral position, the inlet and third actuating lines are connected with the outlet line. The first two actuating lines are cut off. The inlet line of the unit is connected with its outlet line through a normally closed pressure valve whose spring space is connected to the spaces of the hydraulic cylinder through the OR valve. EFFECT: expanded functional capabilities. 2 cl, 1 dwg