Patent ID: 7637139

Claim:
A continuous working system of a press machine, comprising: a ram; an operation shaft which vertically moves the ram; and a servo motor which operates as a power source of the ram and which generates ram pressure using a torque based on at least one speed-torque characteristic of the servo motor; wherein the operation shaft is directly driven using the servo motor, wherein the operation shaft is continuously reciprocated and turned through an angle range corresponding to a distance between a predetermined lower end position required for press working by the ram and an upper end position such that the ram vertically moves between these positions by the servo motor, thereby subjecting a work to a continuous press working, wherein the upper end position is set to a position slightly below a medium height of an entire vertically possible stroke of the ram, and wherein the lower end position is set to a position slightly above a bottom dead center of the entire vertically possible stroke of the ram.