Patent ID: 6401516
Filing Date: 2002-06-11
Classification: B21J

Abstract:
A forging apparatus comprising:a support; at least one tool-bearing slide on said support formed with a piston having a closed end provided with a forging tool and at least partially hollow and open toward an opposite end of said piston; a cylinder on said support in which said piston is guided, said cylinder having a cylinder lid at said opposite end of said piston, said cylinder lid being provided with a passage delivering a hydraulic medium to said cylinder and an interior of said piston, and with an outlet for said hydraulic medium; a valve seat formed in said piston; an axially displaceable tubular valve lifter guided on said cylinder lid, extending into said piston and engageable with said valve seat, said valve lifter forming with said valve seat a valve closing communication between said cylinder and said outlet, said valve lifter being provided with side channels in said cylinder lid for connection with a chamber surrounding said valve lifter and communicating with said outlet, said valve lifter controlling flow between said passage and said outlet, said chamber being maintained without pressure by said outlet; and an actuator connected with said valve lifter for operating same.