DOUBLE ACTION PRESS HAVING FLOATING PUNCH

摘要

A double action mechanical press, especially for performing a blanking operation and a forming operation on each cycle thereof, having a first slide and a second slide, wherein the slides have separate strokes. The slides are reciprocated by means of a crankshaft and connecting rod assembly comprising a single crankshaft and a plurality of connecting rods wherein the throws of the crankshaft can be differently dimensioned and angularly offset relative to each other so as to provide different stroke lengths for the slides and to cause one slide to lead the other. A guide bushing assembly is connected to one of the press slides, and a blanking punch is received in the guide bushing for reciprocating movement relative to the bushing along the same direction of reciprocating movement as the slides. A preloaded antifriction bearing is positioned between the punch and bushing assembly, and serves to maintain the proper clearance between the punch and the corresponding cutting edge on the lower die half. A forming die is received in the guide bushing assembly for reciprocating movement relative thereto and is connected to the other press slide. The other portion of the punch is formed as a piston and is urged downwardly by pressurized air. The travel of the punch against the pressurized air enables the punch to abut the top of the strip material until the blanking slide strikes it and causes it to blank out the part. Meanwhile, the forming die draws the blanked out part, which is continued to be held by the pressure of the punch against the liftout ring. Thus, the action of the floating punch simulates the dwell provided by a cam driven punch.