Machine tool hydraulic drive control - has lever operated spool valve controlling flow to cylinder chamber and chamber of inlet pipe receivable in bore of piston rod

摘要

The control system is for the drive of presses or other machine tools. The working stroke is produced by a pressure-medium actuated piston cylinder arrangement. The arrangement (12, 25) contains a hollow piston (25) and has a fixed pressure medium supply inlet (29A). The connection is sealed relative to the piston, and is in a hollow (28), formed by the piston and piston rod (25A). The supply end facing a control unit (35) is open. A transverse recess (32) near the other supply end feeds the pressure medium to the pressure side of the cylinder (16A), when the pressure is sufficiently high, or seals it against a space (30) in the control unit, when insufficient.