Die changing system including moving bolsters

摘要

A die changing system for a press includes a single push-pull drive system and a double push-pull drive system which move roller supported bolsters along a T-shape track system. Each bolster includes a stationary set of rollers to roll along one section of the T-shaped track system and a retractable set of rollers to roll along the other section of the T-shaped track system. The retractable rollers are moved utilizing a pressurized hydraulic fluid system. Each drive system includes a two speed oil-shear drive which operates at high speed to rapidly move the bolster to a near-final position and then switches to low speed to provide an accurate final positioning for the bolster and its associated die set.