Hydraulic drive for a punch of forming machine has an active surface acting in the driving direction and delimiting an annular chamber which is connected to a switching valve

摘要

Hydraulic drive has an active surface (30) acting in the driving direction and delimiting an annular chamber (32) which is connected to a switching valve (10). The annular chamber is impinged with a supply pressure in the original position of the switching valve and with a lower supply pressure when a predetermined loading pressure is exceeded. An independent claim is also included for a switching valve for the hydraulic drive. Preferred Features: The switching valve prevents the connection of the annular chamber with a tank line (16) and permits a pressure flow in the counter direction. A tank line damper is provided in the tank line.