Patent GB-158881-A (GB)
Title: A machine for the manufacture of bolts of annular spring clasps more especially usedin jewellery
IPC: B21F45/00
Filed: 1921-02-04
Abstract: 158,881. Lemaitre, G. Feb. 10, 1920, [Convention date]. Fastenings; jewellery.-In a machine for making the bolts of annular spring clasps for jewellery &c. of the kind shown in Fig. 19, consisting of wire of semicircular section curved to the required diameter and bent at both ends so that the plane faces fit against each other and with the operating knob formed by a fold in the wire, the wire is fed by a reciprocating gripper, a length is cut off, and bending is effected first by a punch engaging a removable ribbed former to form the fold for the operating knob, then by a slide carrying levers for curving the wire on the former and bending down the ends over the edges thereof, then by a second vertically movable punch to bend the ends against the underside of the former, next by the levers which are operated by a wedge when the former is withdrawn and operate in conjunction with the second punch, and finally by fixed and horizontally movable recessed blocks, all the movements being controlled by cams on a single continuously rotated shaft. The wire is fed from a reel by a slide 3, Fig. 3, pushed forward against the action of a spring by a cam and lever, the wire being' clamped to the slide by a plate 11 pressed down during the forward motion bv a roller on a lever 14 operated by a cam 17 and rod 16. The wire is guided during the forward motion in the channel in two-part rod 18, Fig. 4, secured in a block 19 adjustably mounted in a support 20, and is held stationary during the rearward motion by a pin 21 carried by a plunger 22 pressed by a spring 24 against a cam 23. A notched punch 41, Fig. 9, carried by a slide 42, Fig. 6, pressed by a spring 44 against a cam 45, now moves down to form a form a fold in the wire on a curved ribbed former 33, Fig. 9, and to hold the wire while it is severed by a cutter 25 mounted on a slide 26, which is operated by a lever pressed by a spring against a cam-operated rod. A second slide 43 carrying levers 48 pressed apart by a spring is next forced down by a cam against the action of a spring, together with a wedge 51 on a separate cam-operated slide 51<a>. In this movement the wire is bent by the levers to the shape of the former and the ends are bent over the edges of the former. The punch 41 now rises and a spring-controlled punch 57 is pushed up by a lever pressed against a cam-operated rod so as to bend back the overlapping ends against the underside of the former as shown in Fig. 11. The former is now withdrawn by cam-operated levers 38, Fig. 6, against the action of a spring 37 and the wedge 51 moves relatively to the slide 43 and so engages rollers 66 secured to the levers 48 to press them together so that in conjunction with the punch 57 the plane surfaces of the wire are pressed together and the neck of the knob partly formed. The punch 57 now recedes and the slide 43 and wedge 51 move down together to place the blank opposite the recess 68 and upper portion of a circular groove 67 in a block 69. A hollow grooved block 70, Fig. 6, is now pushed forward by a cam 75 and lever 74. A pair of pins 72. normally projected by a spring through the end of the block, serve to support the blank when the levers 48 are opened. The blank is forced by the block 70 into the recessed block 69 to complete the bolt and on withdrawal of the block 70 the completed article drops out.