GB491656A - A new or improved process of making tubular members or articles and an apparatus anddie therefor - Google Patents

Abstract

491,656. Making tubular rivets. NATIONAL MACHINERY CO. March 6, 1937, No. 6698. Convention date, April 1, 1936. [Classes 83 (ii) and 83 (iv)] Forging ; drawing.-In making tubular rivets and the like, blanks 11 of solid cross section are placed in a die 12 Figs. 1, 3 and 4, with bores 13, 15 of different diameter connected by a tapered throat 14, the blanks being acted on in succession by a header 20 and punch ejector 16. The punch ejector is at first stationary while the header forms a swelling on the part of the blank outside the bore 13 and a depression is formed in the other end of the blank by pressing against the punch element 18. The inner end of the blank is forced outward to the wall of the bore 15 and when the header is forced still further inward, as shown in Fig. 3, the head 23 is formed and the blank pierced to force the metal outwards against the wall of the bore 15. The heading tool recedes and the punch moves forwardly first to draw the tubular part and subsequently to eject the finished article as shown in Fig. 4. In a modification, the tubular rivet is made with the open end tapered, the die having a correspondingly shaped face, which allows of the ejector being of the same size as the bore of the die in which it slides. The part of the die enclosing the blank may be separate from the other part.