GB577417A - Production of cupped articles with walls of tapered section - Google Patents

Abstract

577,417. Making projectiles. PRESSED STEEL CO., Ltd., KELLEY, G. L., and PETHER, A. H. Oct. 9, 1941, No. 13044. [Classes 83 (ii) and 83 (iv)] Cupping.-A cupped article with tapered walls, such as the end of a shell case or bomb, is made from a radially tapered disc 23, Fig. 4, by drawing between a die 31, Fig. 7, and punch 33, at least a part of the annular tapering zone of the disc being engaged by holding means throughout the draw. The holding means may comprise a ring or rings 40, 41 carried by the usual blank holding mechanism 36 so as to be capable of limited vertical movement and backed by a cushion 42 of rubber, pneumatic or hydraulic cylinders, springs or spring- loaded wedges. If the disc is placed on the die 31 with its flat face up, the die face is formed, as shown, to correspond to the conical or convex face 123, Fig. 4, of the disc and, if this face is up, the ring or rings 40, 41 may have their lower face somewhat inclined. Deep cups may require a series of draws increasing in depth. The cup, if for a bomb end, is then trimmed, machined, drilled and tapped..An inverted press may also be used. A nose 13, Fig. 1, and base 15 made in this way may be welded to a body 11 made from a flat sheet by bending and welding at 12. The Provisional Specification describes the replacement of the blank-holding ring 40 by others of successively smaller diameter in multi-stage drawing.