method and tool for the manufacture of an end closed hohlkörpern from sheet with a thickness at the closed end.the thickness of ausgangszuschnittes exceed

摘要

899,438. Making projectile shells; forging; cupping. SVENSKA METALLVERKEN A.B. Nov. 17, 1959 [Nov. 17, 1958], No. 38982/59. Classes 83 (2) and 83 (4). A hollow metal article, particularly a projectile, having a closed end of increased wall thickness, is made by forming a sheet metal disc into a cup 26, Fig. 3, and then upsetting the closed end, Figs. 5, 6, to give it the required profile and increase its wall thickness. A disc of copper-plated iron sheet is deep drawn into a preliminary cup 9, Fig. 1 (not shown), further drawn into an intermediate cup 17 and then drawn through a die 24 into the shape 26. The irregular open end is then removed, preferably on a lathe, Fig. 4 (not shown), and the cup is upset in two stages, Figs. 5, 6, in successive dies 33, 39, by respective punches 30, 40. The dies have air vents 35 and the punches have sharpedged grooves into which the metal is pressed to facilitate withdrawal of the workpiece with the punch.