GB810520A - Metal-tube extrusion press - Google Patents

Abstract

810,520. Extruding; billet piercing. SCHLOEMANN A.G. Sept. 25, 1956 [Oct. 3, 1955], No. 29253/56. Class 83 (4). A metal tube extrusion press has a billetpiercing mandrel 7 mounted in a mandrel holder 18 supported during the piercing stroke against a bush 20 in a mandrel cross-beam 17 but movable independently thereof in the direction of extrusion so as to permit the mandrel to move forwardly with the extruded metal, the support bush 20 being movable axially by means of an adjusting device 23. In the production of aluminium tube, heated aluminium billets 8 are inserted into the bore 5 of the billet container 4 and are first upset against the extrusion die 3 by means of the press ram 6 actuated by a fluid. pressure plunger 10. An extension 12 of the plunger is connected to a withdrawal cross-beam 13 which is in turn connected by adjustable rods 39 to the mandrel cross-beam 17 thus causing the mandrel 7 to move downwardly with the ram 6. The mandrel is then moved downwardly to pierce through the billet by double-acting hydraulic cylinders 33. The ram 6 then extrudes the pierced billet between the mandrel and die to form a tube, the mandrel 7 being permitted to move downwardly by the friction of the extruded metal, until an end member 28 at the end of the mandrel holder 18 engages a stop 41 at the top of the cross-beam 17. The member 28 carries a pair of plungers 50 operating in fluid damping cylinders for damping the independent movement of the mandrel. The adjustable screwed rods 39 determine the downward piercing movement of the mandrel. The mandrel holder 18 has a shoulder 19 which initially abuts against the bush 20 screwed within the mandrel cross-beam 17. This bush is adjusted by a worm and worm-wheel 26, 23. An adjustable stop 30, Fig. 2 (not shown), operates a switch 34 on the mandrel cross-head 17 for stopping the extrusion stroke immediately before the end member 28 engages the stop 41.