Patent ID: 6804979
Filing Date: 2004-10-19
Classification: B21D

Abstract:
Apparatus for sealing an end portion of a tubular workpiece placed in a mold for internal high-pressure shaping of the workpiece, said apparatus comprising:a housing having a pressure compartment in fluid communication with an interior space of the workpiece; and a pressure application unit including a pressure source for supply of a hydraulic high-pressure fluid to the pressure compartment; a pressure piston constructed for displacement solely by admission of hydraulic fluid from the pressure source and accompanying increase in pressure within the pressure compartment and defined in the pressure compartment by an effective piston area which is greater than a cross sectional area in the interior space of an end portion of the workpiece, a sealing mandrel at least indirectly connected to the pressure piston and constructed for forced flat engagement against a confronting end face of the tubular workpiece, thereby sealing an interior of the tubular workpiece without projecting into the tubular workpiece, and a check valve disposed in an axial passageway an the pressure piston and the sealing mandrel between the pressure compartment and the interior space of the workpiece for blocking in a direction to the pressure compartment.