MEANS FOR ACCEPTING HYDRAULIC OIL IN AND THEN DISCHARGING THE SAME FROM HYDRAULIC SYSTEM

摘要

PURPOSE: To prevent generation of any problem following leak of gas and eliminate a low pressure accumulator by providing a receiving cylinder and a high pressure cylinder axially arranged to cooperate with each other and form a functional unit. CONSTITUTION: When a piston rod 3 is making a quick stroke, a valve 32 in a discharge conduit 16 is opened, while a valve 10 in a bypass pipe 9 is closed. Hydraulic fluid flows in an arrow direction to be forcedly sent from a supply conduit 8 into a work cylinder 1, but it is also mechanically sent from a high pressure cylinder 13 into the cylinder 1 by a device 30 mutually and alternately powered mechanically by a piston 19 of a receiving cylinder 12 and a piston rod 31, and by the force of hydraulic fluid pressure to a piston 19 supplied simultaneously from the side 5 of the cylinder 1. As the rod 3 of the cylinder 1 reaches an upper end position, the valve 32 is closed, and the valve 10 is opened, so a direction is changed to make a slow stroke. At this time, a surface of a piston 2 is larger on the side 5 than on the side 4, so it is moved downward.