PNEUMATISCHE ODER HYDRAULISCHE KOLBEN-ZYLINDER-EINHEIT MIT SERVOSTEUERUNG

摘要

A pneumatic or hydraulic piston-cylinder unit, for example the drive of a pneumatic or hydraulic straightening press, has a cylinder (1) containing a piston (3) connected to a press ram (7). The piston (3) divides the cylinder (1) into a return stroke chamber (5) and a propulsive stroke chamber (4). A servo control valve (11) inside the piston (3) is actuated by an adjusting rod (20) and, in function of the piston movement and of the movement of the adjusting rod (20), connects the propulsion chamber (4) to a return line (19) or to the return stroke chamber (5), which is connected permanently to a source of pneumatic or hydraulic pressure. Follow-up control of the piston (3) and the press ram (7) to which it is connected is thereby achieved.