Hydraulic press without conventional side slabs and cross-head

Abstract

A 2000 ton hydraulic press is designed to eliminate the side slabs and substantial cross-head associated with conventional presses. The press simply has a base that includes a lower platen and bolster plate. Four vertical posts extend upwardly through the lower platen bolster plate, and guide structure beneath the lower platen bolster plate constrains the posts to move vertically while bearing horizontal forces and bending moments which may be applied to posts for example during compression of a mold containing a molding charge. Four large-bore, short-stroke hydraulic cylinders are attached to the base below the lower platen bolster plate, and serve to raise and lower the posts during compression phases of operation. An upper platen is interfitted with and guided exclusively by the posts for vertical movement, and a pair of small-bore, long stroke cylinders operating between the lower and upper platens serve to raise and lower the platen in a rapid manner in preparation for and following compression-phase operations. Hydraulically actuated locking mechanisms carried by the upper platen permit the upper platen to be fixed to the posts so that the four large bore cylinders can be actuated to draw both the posts and the upper platen downwardly, as during compression of a work-piece between the platens.