APPARATUS FOR FORMING METALS BY MEANS OF JET LIQUID

1,131,400. Stamping; angular bending; perforating. TOKYU SHARYO SEIZO K.K. 18 March, 1966 [18 March, 1965; 23 April, 1965; 17 June, 1965; 27 Aug., 1965(2)], No. 12163/66. Headings B3E, B3Q and B3W. Apparatus for stamping, bending or punching holes in sheet metal comprises a chamber containing a liquid into which a plunger is driven for generating a work-forming pressure wave and a passage of decreasing cross-sectional area leading to a nozzle through which issues a jet of the liquid. A blow may be struck on the plunger 3, Fig. 1 by an air-punch for forcing a jet (9) of water against the workpiece (11) to form it into a die (10). Several strokes of the plunger may be required, and the jet-pressure on the work-margin may serve as a hold-down. The die may be in sections and perforated (12), Fig. 3 (not shown), where holes are required in the workpiece. If irregular holes are required (15), Fig. 5 (not shown), the workpiece (11) is held against the die (10) by a clamp (16). The jet (9), Fig. 4 (not shown), may neck a tubular workpiece (11) about dies (13, 14). The workpiece is preferably heated; hardness and workability may be influenced by using quenching oil as the jet liquid. The pressure wave, passing along the convergent passage (20), Fig. 8, may form the workpiece (22) by fluidinflation. In another construction, Fig. 11 and Fig. 12 (not shown), the passages in the chamber 1 and in the die 21 contain steel transmission mediums 31, Fig. 11, and (35) Fig. 12 to accelerate a part of the pressure wave 1 which is thus first to strike the workpiece (29), the remainder of the shock wave completing the forming operation. A plurality of jet nozzles may be provided, Fig. 10 (not shown).