Abstract: A plurality of die cylinders adapted to contain gas under pressure are mounted on a manifold. Each cylinder comprising a cylinder body having an axially inner cylinder portion and an axially outer cylinder portion. A piston has an axially inner end portion extending into the inner cylinder portion and an axially outer end portion surrounded by the outer cylinder portion. A seal is provided between the inner end portion of the piston and the inner cylinder portion. There is a removable sealing cartridge between the outer end portion of the piston and the outer cylinder portion. A snap ring removably retains the cartridge on a shoulder between the inner and outer cylinder portions. The piston is capable of full axially outward retraction and separation from the cylinder when the cartridge is removed. The cylinder is free of any obstruction which would interfere with the axially outward retraction and separation of the piston when the cartridge is removed.

Abstract: A die stamping system in which an upper die moves downwardly toward and upward away from a lower die to stamp a workpiece, and in which a portion of the lower die is supported by at least one gas cylinder coupled to gas under pressure to cushion downward movement of the lower die portion and delay upward movement of the lower die portion. Each gas cylinder has a piston reciprocable within a vertical cylinder body. The piston has an upwardly extending piston rod for engaging the lower die portion. The cylinder body has a lower portion beneath the piston connected to the gas under pressure. A first passage connects an upper portion of the cylinder body above the piston to the lower portion of the cylinder body beneath the piston. A second passage connects the lower portion of the cylinder body to a tank. A third passage connects the upper portion of the cylinder body to the tank. First, second and third valves in the respective first, second and third passages control gas flow.