Deep-drawing press

Claim 1

A deep-drawing press with a multi-state die set consisting of a plurality of successively arranged dies and punches moving telescopically within each other, after performing a predetermined drawing movement the punches exert pressure on an associated die acting as a hold-down ring, a drive consisting of the same number of coaxial annular pistons attached to said punches, the pistons being subjected to the influence of a pressure medium, and a control means that permits all of the said annular pistons to be moved axially in sequence, from the outside inward, characterized by the fact that the control means comprises coaxial plunger type valves (20 and 21) integral with the first, second and penultimate annular pistons (10, 11 and 12), with elements for the flow of pressure medium to the end faces of said annular pistons, said plunger type valves (20 and 21) having elements acting in succession in the manner of a sequence control to control the flow of pressure medium to pressure chambers (30, 31 and 32) in front of the second and penultimate annular pistons, the backs of the first to penultimate annular pistons (10, 11 and 12) are provided with differential piston surfaces (35) so that, after the lifting of stop rings (34), through which adjacent annular pistons engage each other in the inward position, said pressure medium flows on the one hand to the working face and on the other hand to the differential piston surface (35) of the pistons, thereby determining the differential pressure exerted by the respective annular pistons.