GB127699A - Improvements in and relating to the Forming and Stamping of Metallic Cartridge Cases and like Containers. - Google Patents

Abstract

127,699. Curran, C. J. May 27, 1918. Cupped articles.-To economize power and enable mechanically-operated presses to be used in heading and tapering metal bases of cartridges &c., the head portion of a plain cupped blank is first pressed, within a restricted die space, to produce a plurality of thickened and indented zonal areas within the circumference of the cylindrical part of the blank, and is then pressed, in an unrestricted die space, to produce the final form having a rim or bead extending beyond the circumference of the cylinder, the cylinder at the same time receiving the required taper. The plain blank a, Fig. 1, is placed within a socket d on a die of tapering form, the diameter being least at its upper end. The upper surface is provided with a recess k and may also have a slight annular depression o. The upper die c has a projecting nose h, annular projection m, shoulder r, and circumferential lip t. These dies bring the blank to the form shown in Fig. 3, which also shows the dies for effecting the completion of the process. The lower die is of tapering form, the diameter being greatest at its upper end, which is level with the socket Z. The upper die W has a nose 5, stepped portion 11, and depending portion 12 to restrict outward flow of metal. The action of these dies brings the head to the final form shown in Fig. 5, and at the same time the wall b is caused to contract into contact with the tapered inner die, spring out again, but not to its original diameter, when the pressure of the upper die is removed. Modified forms of the die W are described, in one of which the die is bounded by a set-back portion in place of the lip 12. A modified form of the die c is also described in which the shoulder r is replaced by a rib only slightly less prominent than the projection m.