Hydraulic system for sheet metal press - has one-way valves to connect cylinder chamber, and includes pressure reduction valve

摘要

The hydraulic system is for tools or presses, to process sheet metal. It has two working cylinders (10,11), the chambers of which are in flow connection to charge pistons in the cylinders. One cylinder is formed as a forming cylinder, the other as plate holder cylinder. The rear cylinder chambers (16,21) are connected via two opposite parallel one-way valves (37,38), which permit a hydraulic medium flow in one direction only. The chamber (16) of one cylinder (10) is connected to a pressure accumulator (51), which is at a preset pressure, via one-way pressure reduction valves (44,57), with opposite flow directions. The valves are opened, when a pressure differential arises, which is larger than the set pressure level. Normally, the valves close the connection between accumulator and cylinder chamber.