Patent GB-633963-A (GB)
Title: Improvements in machines and methods for making slide fasteners
IPC: B21D53/50
Filed: 1947-07-28
Abstract: 633,963. Making sliding-clasp fasteners. CONMAR PRODUCTS CORPORATION. July 28, 1947, No. 20251. Convention date. March 28, 1939. [Classes 83 (ii) and 83 (iv)] Apparatus for the manufacture of slide fasteners from a strip 128 comprises a device for intermittently and longitudinally feeding the strip over a spring pad 120 and on to a stationary die portion 124, a device for intermittently feeding a tape 50 in such a manner that each feed movement of the strip brings the foremost element to a position in which its spread jaws are astride the edge of the tape, a device for clamping said jaws on the tape, and a timing mechanism controlling a reciprocating severing punch 118, arranged above the spring pad and having a part mating with the stationary die portion to complete a cutting stroke after each operation of the strip feeding device, and causing clamping of the element on to the tape, followed by at least a partial operation of the tape feeding device between successive strip feeding operations, the spring pad restoring the strip, on return retraction of the punch, to its original position. Shearing; angular bending.-The punch 118 is carried by a ram 196 reciprocated by a U- shaped rocker 78, Figs. 9, 10, operated by a cam-shaft 72, the stroke being adjusted by a screw 198. The element 122 rests on the stationary die portion 124 and may be held by a spring-pressed pad 126, and the descent of the punch forces the strip 128 and spring pad 120 downwards, Fig. 15, the element being sheared from the strip 128. When the punch again rises, the strip is lifted by the pad 120, the jaws 42 at the end of the strip encompassing the head 40 of the severed element. Fins 38, which may be left on the strip are preferably removed by the shearing punch which is suitably shaped, the scrap being blown away by compressed air supplied by flexible tubes 170 and directed downwardly at the die, Fig. 11. The endmost element is clamped on to the tape by clamping plates 212 secured to levers 214, pivoted at 216 and carrying cam followers 218 running between cylindrical cams, Fig. 11, carried on the cam-shaft 72. The strip may be of the form described in Specification 540,605 and may be formed from round or flat wire by rolling as in Specification 539,525, or plain fiat strip may be used, in which case the apparatus includes a forming punch to provide the projections and recesses. A finishing punch 182 (Fig. 15) may form part of the punch assembly, and forces the severed elements into a recessed portion 184 of the stationary die part, to round the corners of the head. The manner in which the shearing punch 118, holding pad 126 and finishing punch 182 nest together is shown in Fig. 24. Feeds.-The tape 50 is fed intermittently upward by a drum 86 moved by a ratchet mechanism operated by the cam-shaft 72, which also operates a reciprocating feed pawl 130 by which the strip 128 is fed intermittently toward the tape 50. When the spring pad 120 and strip 128 are depressed by the punch 118, the strip is disengaged from the pawl 130, Fig. 15, the timing of the cam-shaft being such that the pawl moves forward when the punch is elevated and backward when the punch is down. The pawl is pivotally mounted in a reciprocable slide 141 normally retracted by springs 142. The feed may be interrupted to produce a gap between stringers by a counter mechanism 112 which after a predetermined number of operations, energizes a solenoid 116, which moves a block beneath the end of the rocker 78, thus locking the punch in its down position, so that the pawl reciprocates idly.