GB433829A - The production of tubular metal cases such as cartridge cases - Google Patents

Abstract

433,829. Making cartridge cases. BIGINELLI, O., 30, Rue Bonnabaud, Clermont- Ferrand, Puy-de-Dome, France. Aug. 22, 1934, No. 24216. Convention date, Aug. 22, 1933. [Classes 83 (ii) and 83 (iv)] A cartridge-case, or like tube with a thickened closed end, is produced by applying axial pressure to a portion at one end of a tube, which portion is supported over its whole outer surface, but is free on its internal surface, the pressure being confined to this end portion of the tubing by an abutment member. Drawing; tube-expanders.-A drawn tube of cylindrical form is supported between a guide member 3, Fig. 9, and a matrix 4 having a bore 11 which is partly conical at the inner end, and the end of the tube projecting from the matrix is expanded by the enlarged portion of a mandrel 1. The abutment 5 and the mandrel 1 are retracted, and a series of balls 18, Fig. 11, are introduced through an inlet 10 and successively forced through the tube to expand the portion within the matrix against the wall of the bore, and then to draw out the tube in length. Alternatively, a long mandrel having a series of enlarged portions corresponding in size to the series of balls may be used. Forging; pipe-end closing.-The tube so formed is transferred to a press comprising a rotary matrix 31 having a gear 38 for engaging a driving pinion, a forming-tool 32 and countertools 34, 35, the portion of the tube of enlarged thickness then being acted on by the tool 32 to weld up the opening and to shape the base 23 to the required form. The matrix may be non-rotary and the counter-mandrel and the work rotated. The mandrel 32 may be advanced by a screw, a hydraulic press, or other means. The space 48 between the heads is filled with oil. The tube 50 after removal from the press is trimmed and shaped to the final form shown in Fig. 24.