Patent ID: 6460396
Filing Date: 2002-10-08
Classification: B21D

Abstract:
A power press comprising:a. a stationary die, b. a movable die movable toward the stationary die along a die closing and opening axis, c. a ram for urging the movable die toward the stationary die along the axis, d. a force modulator operatively connected to exert a force in the direction of the axis between the stationary die and the movable die, the force being variable in response to the position of the movable die relative to the stationary die, the force modulator comprising: e. a base plate, f. a movable plate that is movable relative to the base plate, g. a resilient pneumatic bellows having one end sealingly mounted on the movable plate, said resilient pneumatic bellows having an opposite end sealingly mounted on the base plate, h. a vessel connected to one of said plates, i. a metering cylinder mounted on the same plate as the vessel and being positioned within the vessel, j. a piston assembly slidably mounted in the metering cylinder, k. a piston rod having one end connected to the piston assembly and an opposite end connected to the other of said plates, said metering cylinder having a plurality of orifices along its length to regulate the flow of hydraulic fluid from the metering cylinder into the vessel as the piston assembly moves from a starting position into the metering cylinder and thereby regulate a force on the piston rod in response to the position of the movable plate relative to the base plate and thereby coact with the defined force applied by the ram.