PRESS HAVING CUSHIONING CYLINDERS EACH HAVING TWO CHAMBERS WHOSE PRESSURE DIFFERENCE IS ADJUSTABLE TO CONTROL BLANK-HOLDING FORCE

摘要

A press wherein a blank-holding force generated by cushioning cylinders is transmitted to a pressure member through cushion pins for holding a blank during a pressing operation by a die and a punch, and is controllable by a pressure adjusting device according to an optimum pattern of control by controlling a difference between fluid pressures in two pressure chambers of each cushioning cylinder whose volumes decrease and increase, respectively, as the cushion pins are lowered.