Patent ID: 6679164
Filing Date: 2004-01-20
Classification: B30B

Abstract:
A press machine comprising:a base with a table surface for supporting a workpiece; a guide member having one end connected to said base; a support plate connected to another end of said guide member; ball screw arrangement having screw shaft, a nut member and a plurality of balls between said screw shaft and said nut member; a slide plate being movable in a pressing direction toward and away from said base; said support plate rotatably connected to said screw shaft of said ball screw arrangement; a movable device adjusting a distance between said slide plate and said table surface in said pressing direction, said movable device includes a first movable body and a second movable body, said movable device includes a differential member arranged between, and slidably engaging with, said first and second movable bodies, said differential member being movable in an adjusting direction substantially orthogonal to said pressing direction, said first and second movable bodies and said differential member being shaped to have movement of said differential member with respect to said first and second movable bodies cause said first and second movable bodies to expand and contract in said pressing direction, expanding and contracting of said movable bodies adjusting said distance in said pressing direction between said slide plate and said table surface; a press motor connected to said screw shaft and rotatable of said screw shaft; an adjustment motor connected to said differential member and movable of said differential member in said adjusting direction; a control unit controlling said press motor to move said slide plate between a first and second position with respect to said table surface, said control unit also controlling said adjustment motor to move said differential member, said control unit adjusting operation of said pressing motor to maintain said slide plate moving between said first and second positions so that said distance between said first and second positions is kept constant after said adjustment motor moves said differential member.