GB1349059A - Production of deep drawn pressings - Google Patents

Abstract

1349059 Making hollow-ware; cupping ALCAN RESEARCH & DEVELOPMENT Ltd 24 May 1971 [2 June 1970] 26662/70 Headings B3A and B3Q [Also in Division B6] A punch - and - die set for drawing tapered shells from metal sheet or foil comprises a die with a tapered recess and a punch with a compliant end the nose of which has substantially the same dimensions as the diemouth. Aluminium or aluminium alloy, which may be lacquered or laminated with polyethylene or polypropylene, may be used to form cylindrical or oblong shells or shells having recessed walls. In one form of punch, Fig. 1, a tapered ring 16 of elastomeric material (e.g. rubber or a polyurethane) forms the compliant end which may be compressed into an inner space 18 as it enters the die, the depth of the ring being approximately the same as that of the die-recess. The diameter of the ring 16 may be less rearwardly of its nose 17a; the ring may alternatively be formed of a series of parts separated by metal spacers. In another form, Fig. 2, an elastic envelope 22 bonded to a carrier 20 is filled with oil which is pressurized, e.g. by a gas accumulator. Other forms of punch keep the compliant ring, when may be in segments, under pressure with springs (48, 49<SP>1</SP>, Fig. 5). In another form, Fig. 6, which the envelope is connected by passages 67 to an hydraulic accumulator its diameter approximately equals that of the die mouth. A bolt 68 for clamping the nose of the envelope has a vent passage 72 and is biased by springs 70. A recessed form of compliant member (Fig. 7) is secured by a central bolt. The punch 11, Fig. 4, is surrounded by a trimming cutter 34, a clamping ring 32 and a outting-out ring 31. The die 1 has a resilient backing 37 and an ejector 38 and is surrounded by a cutting-out punch and a spring-loaded stripper 39.