Patent ID: 6085520
Filing Date: 2000-07-11
Classification: B30B

Abstract:
A slide driving device for a press comprising:means for generating pressure in a hydraulic fluid;said means for generating pressure includes an accumulator;means for controlling said pressure to maintain said pressure within said accumulator within a prescribed range;said pressure being substantially constant during changes in a load on said press;rotating means, responsive to said pressure, for converting energy from said hydraulic fluid into rotational power;said rotating means including means for absorbing rotational drive force from said slide through said means for applying rotational power, and for converting said rotational drive force into stored energy for said hydraulic fluid, said stored energy being stored temporarily in said accumulator;said rotating means includes at least one variable displacement pump/motors and at least one fixed volume pump/motors;means for applying said rotational power to a slide driving mechanism of said press;means for varying a displacement volume of said rotating means; andmeans for controlling said displacement volume, thereby controlling a drive torque applied to said slide driving mechanism.