Press for hydrostatic extrusion of tubes

Abstract

A press for hydrostatic extrusion of tubes includes a high pressure cylinder axially displaceable in a press stand with a die insertable into the cylinder and a pressure generating punch insertable into the cylinder to generate the pressure for extrusion. A mandrel is carried by a rod which passes through the pressure generating punch. Seals are provided between the mandrel and the pressure generating punch and between the pressure generating punch and the pressure cylinder. These seals are so located that during the actual extrusion they are arranged in the same transverse plane.

I claim: 
     
       1. Press for hydrostatic extrusion of tubes, comprising a press stand, a pressure chamber constituted by a high-pressure cylinder axially displaceable in the press stand, a die insertable into the cylinder and a pressure-generating punch insertable into the cylinder to generate the pressure necessary for the extrusion process in a pressure medium enclosed in the pressure chamber, said pressure medium surrounding a billet to be extruded, a mandrel part which shapes the hole through the tube, which includes a rod part passing slidably through the pressure-generating punch, said mandrel part being supported by said rod part, a first seal .Iadd.fixedly arranged at the end of the pressure chamber remote from the die .Iaddend.sealing between the high pressure cylinder and the pressure generating punch and a second seal sealing between the pressure generating punch and the mandrel, said second seal being .Iadd.carried by said rod and .Iaddend.axially stationary in relation to the first seal during the extrusion period of an operating cycle and approximately in the same radial plane as said first seal. 
     
     
       2. Press according to claim 1, comprising an operating cylinder and an operating piston slidable in the operating cylinder operatively connected to the rod part. 
     
     
       3. Press according to claim 1, the axial distance between said seals being less than the radial distance between these seals when the rod part and the cylinder are fully advanced. .Iadd. 
     
     
       4. Press according to claim 1, the second seal being at substantially the same distance from the die end of the mandrel as the distance of the first seal from the die end of the pressure chamber..Iaddend.