Patent GB-602853-A (GB)
Title: Improvements in or relating to riveting
IPC: B21J15/04
Filed: 1946-02-14
Abstract: 602,853. Riveting. BRITISH UNITED SHOE MACHINERY CO., Ltd., COOPER, B. P., and HENSHAW, J. N. Feb. 14, 1946, No. 4582. [Class 43] A mandrel for use in blind riveting is such that when it has been pulled sufficiently to set the rivet, it is slightly indented so that it breaks under the continued pull. Use is made of a tool wherein the rivet is held up to the work by means pivotally mounted in such' a way that reaction between the rivet and said means causes the latter to indent the mandrel stem at a predetermined stage in the riveting operation. The tool is somewhat similar to that described in Specification 348,818, but in the present case the lower end of the casing 1, Fig. 2, is internally threaded, and has secured to it a bored member 49 through which the lower end of the sleeve 3 projects. The lower end of the member 49 is bifurcated, each bifurcation providing two ears 51, and each opposing pair of ears having secured to them a pin 53 on which is mounted a lever 55 having a serrated lower edge to which a serrated steel jaw 57 is adjustably secured by screws. The jaws 57 approach one another when the magnitude of the setting pull reaches a predetermined degree, but normally small clearances 65 exist between the front and back edges of the jaws, and tapering recesses 67 therein together form an opening for the mandrel stem; the jaws thus support substantially the whole of the rivet head during setting. To maintain the clearances 65 each lever 55 has upwardly extending bifurcations 69 carrying a pin 71 upon which is mounted a roll 73; slidingly mounted on part of the member 49 is a circular member 75 having lugs 77, which extend downwards between the bifurcations 69 and have inclined surfaces 79, which contact the rolls 73 and tend to move them towards one another but are prevented by the engagement of the ends of the pins 71 with faces 81 on the member 49. The member 75 is urged downwards by a rubber ring 82 compressed between it and a thin metal disc 87 backed by an adjustable nut 83 threaded on the member 49. In operation, as a setting pull is applied to a mandrel (such as that described in Specification 602,652) reaction between the rivet head and jaws 57 tends to rock the levers 55 about the pins 53 to make the jaws approach one another; this movement is resisted until the magnitude of the pull is such that the action of the rubber ring 82 is overcome, whereupon the levers rock and the rolls 73 travel along the inclines 79 moving the member 75 upwards to compress the ring 82 still further. The initial clearances 65 are such that, before the jaws 57 completely engage, the edges of the recesses 67 slightly indent the mandrel stem, after which further pull causes immediate breaking of the mandrel. By adjusting the nut 83, and so varying the initial compression of the rubber ring 82. the magnitude of the pull necessary to effect fracture of the mandrel may be varied. When rivets are to be set in relatively confined spaces the end portions of the lever 55 serve the purpose of the jaws 57; these levers extend downwards further than before, and have clearances between, and tapering recesses in, their lower ends as the jaws had; their lower surfaces together provide a small approximately circular, flat face for engaging a rivet head. If the setting operation is to be terminated when the mandrel has been pulled through a predetermined distance, the modified tool of Fig. 7 is used. A cylindrical rod 107 replaces the sleeve 3 and collar of the previous tools, and has in its lower end an axial hole 108 for a mandrel stem held by a set screw 109. Secured in the base of the casing 1 is a member 111 similar to the member 49; levers 117, having lower ends similar to those of the levers used in the second type of tool described, pivot on pins 115 as before, but the levers 117 have upwardly extending arms 119 in which are recesses for the ends of compression springs 121, the open ends of which engage in recesses in the member 111; the springs tend to rock the lower ends of the levers towards one another, but normally surfaces 123 on the levers engage with a reduced part 125 of the rod 107. A constant forward position for the rod 107 is determined by the engagement of a stud 127 thereon with the lower end of a slot 129, in the casing 1. In operation, when sufficient axial movement,has been imparted to the rod 197 and mandrelstem to move the reduced part 125 clear of the surfaces 123 the lower ends of the levers 117 approach to indent the mandrel stem as before. Specifications 504,928 and 564,383 also are referred to.