Patent ID: 8833126
Filing Date: 2014-09-16
Classification: B21D

Abstract:
1. A stretching device comprising: a housing; a first clamping member attached to a first portion of said housing; a second clamping member attached to a second portion of said housing; wherein said first clamping member comprises a plurality of jaws each positioned adjacent and parallel to each other; wherein each of said jaws comprises: a cam profile forming a gripping angle between said each of said jaws and a workpiece to be gripped, and a pivot end which is moved up or down by hydraulic cylinders such that said gripping angle remains the same for various thicknesses of the workpiece, wherein gripping angle results in a gripping force on the workpiece being proportional to a stretching force wherein a ratio of said gripping force to said stretching force remains the same regardless of the thickness of the workpiece.