Patent ID: 6131497
Filing Date: 2000-10-17
Classification: B21D,Y10T

Abstract:
In 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, the improvement wherein said at least one gas cylinder comprises:a piston reciprocable within a vertical cylinder body,the piston having an upwardly extending piston rod for engaging the lower die portion and the cylinder body having a lower portion beneath the piston connected to the gas under pressure,first passage means connecting an upper portion of the cylinder body above the piston to the lower portion of the cylinder body beneath the piston,a tank for containing gas cylinder system operating gas to provide a reservoir supply of the gas under pressure,second passage means comprising said lower portion of the cylinder body below the piston to said tank,third passage means connecting the upper portion of the cylinder body above the piston to said tank such that said tank provides an operating source of the gas under pressure and is operably coupled by said second and third passage means in series gas flow relationship between and to said upper and lower portions of the cylinder body, andfirst, second and third valve means for controlling gas flow in said respective first, second and third passage means.