Patent ID: 7506581

Claim:
A press machine comprising: a frame; a crankshaft having a crankshaft axis and two eccentric portions rotatably borne on said frame; an elevatable slide disposed under said crankshaft and characterized by an elevating stroke length; two sets of levers provided directly on both sides of said crankshaft and supporting said slide, each set of the levers including a first lever swingably borne about an axis parallel to said crankshaft axis, and a second lever connected to said first lever through a first pin parallel to said crankshaft; a displacing mechanism operatively connected to said frame for displacing said first pins and thereby providing an adjustment to the elevating stroke length of the slide; a linear approximation mechanism for exerting a horizontal force to each of said first pins so as to convert a rotation of each of the eccentric portions of said crankshaft into an elevating stroke motion of said slide, wherein said linear approximation mechanism includes said first lever; connections swingably connected to each of the eccentric portions of said crankshaft, wherein said frame is provided with a first groove extending horizontally relative to said crankshaft and slidably supporting said second pin; third levers connected to said connections through second pins parallel to said crankshaft; fourth levers connected to said third levers through third pins parallel to said crankshaft, wherein each of said first pins penetrates one of said fourth levers.