SECURING DEFORMABLE SHEET METAL ELEMENTS

摘要

1,041,119. Jointing by forging; riveted joints. METAL BOX CO. Ltd. March 17, 1965 [May 20, 1964], No. 20876/64. Headings B3H and B3U. [Also in Division B8]. A method of securing one portion of ductile sheet metal 1 to another 4 by superimposing one on the other and clamping them around the area thereof to be secured, creating from the clamped area a substantially frusto-conical formation the sloping sides of which extend across a space formed between rigid walls, and by impact extrusion causing metal from the closed end 7, Fig. 3 (not shown), of the frustoconical formation to flow into said sloping sides thereby to effect deformation and interlocking thereof in said space. An apparatus for carrying out the method comprises a base member 10 supported by springs S and a fixed anvil 12 which has a tapered upper end 14, Fig. 6 (not shown). A spring-loaded hold-down 11 is mounted in the ram R of a press and contains a punch 13, connected to an air cylinder AC, and slidable in the hold-down. Operation.-As the ram R descends, the holddown 11 clamps the sheets together and because the springs S1 are stronger than the springs S pushes the base member 10 down, so that the end 14 of the anvil forms the two layers of metal 15, 16, Fig. 8 (not shown), to a frusto conical shape. The impact of the punch against the closed end 7 causes metal to flow into the sloping sides to produce the interlocking formation, Fig. 9 (not shown). In a modification the end 14 of the anvil is of circular cross-section and is smaller in diameter than the body of the anvil. The end 14 may also be of other than circular cross-section. The opposed faces of the anvil and punch may be mating convex or concave surfaces. In a further modification the holddown 11 is split longitudinally and has a recess 17, Fig. 11 (not shown), which together with the anvil forms a space in which the inter-locking occurs. The preferred thickness of the sheets is 0À010-0À025 inch and the preferred diameter of the finished joint is 3/ 16 to 5/ 16 inch.