GB568013A - Rivets and method and apparatus for making the same - Google Patents

Abstract

568,013. Forging rivets. CHERRY, C. W. April 19, 1943, No. 6254. [Classes 83 (ii) and 83 (iv)] [Also in Group XXV] A rivet assembly, of the type wherein the second head on a tubular rivet is formed by pulling a core through the rivet, comprises a rivet 1, preheaded at 3, Fig. 6, and drilled to form the bore 2, together with a core member 6 headed at 7 before insertion in the bore 2 in which it is a sliding fit. The head 8, for the pulling grip, is formed after assembly and during the upsetting the fit between the bore 2 and the part 6 is rendered closer. During heading, the head 7 rests on the bottom of a bore 13, Fig. 8, in a die 9 counterbored at 12 to receive the head 3. The projecting part of the stem passes through an accurately fitting hole in a die 14 counterbored to receive a die 17 shaped at 18 to yield the form of head 8 required. A punch 19 slides in the die 17 to effect the heading. As embodied in a handoperated machine, the die 9 takes the form of a member 24, Fig. 11, flanged at 41 for support in the platen 22 of a press, and vented at 28 to facilitate insertion and removal of the work. The die 29 is in two parts hinged together, handled for closure, and locked in the closed position by cams (not shown). The die 29 is recessed below to receive the flange 41 and at 42 to receive the die part 49 mounted by means of a pin 51 and slot 52 on the upsetting punch 48 that is secured in a ram 43 operated by hand lever and rack and pinion, with a screw stop 'for limiting the stroke. The part 49 first bottoms in the recess 42 and then the spring 53 is compressed during the formation of the head 8. An automatic machine has a dial plate 68, Fig. 19, carrying three sets of dies 64, and provided with notches 101 to receive a spring and cam-controlled index bolt 99. Indexing is effected by a crank 154, Fig. 13, linked to a hooked arm 156 coacting with rollers 153 on bolts connecting discs 152 on the shaft 67. A spring band 77, Fig. 19, surrounds the dial plate and has one end anchored at 78 and the other connected to a bell-crank 81 for adjustable spring loading at 83. The outer part 73 of each die set is hinged at 74 and as the dial carries the die towards the bottom in Fig. 19, a pin 92 in a cross-bar 89 engages a lug 88 causing the die to swing open. A lug 96 on the moving part strips the assembly from the fixed part and a projection 97 on the dial plate effects stripping from the moving part. As the die is indexed to the position A, the spring band 77 effects the reclosing of the die parts, and at this position a fresh blank is inserted either by hand or by an automatic device. Upsetting takes place at position B where a backing-up ram 107, Figs. 13 and 14, is advanced by a cam 136 against a retracting spring 139 to bring a punch 119 against the head 7, the outer and adjustably mounted member 114 having an annular flange 117 that enters a groove in the die 64 ensuring axial alignment. A second cam 134 then advances the heading ram 121 so that an annular flange on the outer spring-pressed slidable die part 126 enters a corresponding groove in the die 64, further ensuring correct location. The necessary float of the die sections is obtained by mounting them with clearance on pins that also secure cover-plates for the recesses in which the dies are mounted. Drive is applied at 144 to the cam-shaft 146, geared at 149 to the shaft 106 carrying the index bolt cam 104 and geared at 151 to the cam-shaft 150.