Patent ID: 7472897
Filing Date: 2009-01-06
Classification: B21D,F16F

Abstract:
1. A cushion for a ram or bolster of a metal stamping press, said cushion comprising: a manifold comprising fluid-flow passages and a plurality of cylinder mounting locations each in communication with at least one of the fluid-flow passages; a plurality of cushion cylinders located respectively in said plurality of cylinder mounting locations, each cushion cylinder comprising: a body comprising an inner wall that defines a bore having a diameter D; a piston located in said bore and comprising a cylindrical outer surface and opposite inner and outer faces, both said inner and outer faces arranged transverse to said cylindrical outer surface, wherein said outer face is oriented outwardly relative to said bore and said manifolds, and wherein said inner face defines an axially inner most face; a fluid seal supported on said piston and slidably engaged with said inner wall defining said bore; a bearing retainer connected to said piston; first and second axially spaced-apart bearings supported on said piston and slidably engaged with said inner wall defining said bore, said first and second bearings cooperating to support said piston slidably in said bore for reciprocal sliding movement between an extended position, where said piston is located adjacent an outer end of said body, and a retracted position, where said piston is moved axially into said bore away from said outer end of said body, said bearings defining inclusively therebetween a bearing-length L that is less than or equal to 25% of said bore diameter D; wherein said second bearing is located axially inward from said first bearing and is secured to said piston by said bearing retainer with a first part of said second bearing clamped to and covering at least part of said transverse inner face of said piston and a second part of said second bearing projecting outwardly beyond and cantilevered relative to said cylindrical outer surface of said piston and slidably engaged with said inner wall defining said bore such that said second bearing abuts said axially inner most face of said piston, and wherein said fluid seal is located axially between said first and second bearings.