Apparatus for hydraulic deep-drawing of sheet metal

Claim 1

A DRAWING PRESS FOR HYDRAULICALLY DEEP-DRAWING SHEET MATERIAL FROM BLANK OR PRE-SHAPED WORKPIECES, COMPRISING A CONTAINER DEFINING A SPACE FOR HOLDING LIQUID UNDER PRESSURE, SAID CONTAINER HAVING A SURFACE FOR SUPPORTING THE WORKPIECE SO THAT THE WORKPIECE FORMS A CLOSURE FOR SAID CONTAINER, SAID CONTAINER BEING PROVIDED WITH A GROOVE IN ITS UPPER PORTION, AND A RESILIENT SEALING MEMBER OF SOFT MATERIAL WITHIN SAID GROOVE TO FORM SAID WORKPIECE SUPPORTING SURFACE, RETAINER MEANS MOVABLE TOWARD AND AWAY FROM SAID CONTAINER SURFACE FOR SEALINGLY HOLDING THE WORKPIECE THEREAGAINST, A MALE DIE MOVABLE TOWARD AND AWAY FROM SAID CONTAINER FOR PRESSING THE WORKPIECE AGAINST THE LIQUID CONTAINER THEREIN, AND PROGRAM CONTROL MEANS FOR CONTROLLING THE PRESSURE AND FLOW OF SAID LIQUID INTO SAID SPACE IN DEPENDENCE UPON THE WORKING STROKE TRAVEL OF SAID MALE DIE.