GB669830A - Improvements in or relating to the manufacture of zip fasteners - Google Patents

Abstract

669,830. Making sliding-clasp fasteners. FLEX FASTENERS, Ltd. Nov. 17, 1949 [Nov. 26, 1948], No. 30723/48. Class 83 (ii). [Also in Group XXV] Shearing.-A punch for use in the manufacture of interlocking elements of sliding- clasp fasteners is provided with one or two lateral shoulders extending longitudinally of the punch for slidably mounting it in a guide member which has a corresponding guide channel or channels. The machine is of the type in which a metal strip 8, Fig. 2, having preformed projections 5 (and corresponding recesses) is fed step-by-step to a working position at which the elements 3 are severed by the punch, while at the same time the tap 1 is fed to the working position and the several elements clamped thereto. The machine comprises generally a single vertical driving shaft 10, Fig. 3, driven by a motor 11 and operating all the cams or eccentrics required for effecting feed of the strip 8 from a spool 12, for feeding tape 1 from a coil 15, for operating the punch and a clamping tool, and for delivering the tape, after application of the elements, to a take-up spool 17. The tape 1 is drawn through the machine by a drum 20, which rotates step-by-step on an axis parallel to shaft 10. Waste from strip 8 falls through a tube 22 to a box 23 from which air is exhausted by a pump 24. As shown in sectional plan, Fig. 5, the tape passes through a feeler device 27 comprising a spring-pressed block 28 connected to a switch 31 and bearing on the tape, which stops the machine if the variation in tape thickness exceeds a permissible amount. Thence the tape is fed horizontally to the working position where it meets metal strip 8, fed vertically upwards. At this position are arranged the punch 32 and a co-operating die 33, a pair of hammers 34 for clamping the leading element on to the tape, an ejector 35 for ejecting the severed element from the die 33, a punch presser 36, Fig. 7, for urging the punch towards an eccentric 40, Fig. 5, on shaft 10, actuating the punch, and a finger 37, Fig. 7, feeding the strip 8 intermittently. The exploded view, Fig. 11, shows the punch 32 and associated parts. The punch has two lateral guide shoulders 43, and the front part 47 is shaped to act as blanking means. Guide means for the punch comprise a support 44 to which two parts 45, with flanges 46 overlying shoulders 43, are secured. A distance-piece 41 bears on eccentric 40, Fig. 5, and acts on punch 32 through a packing and adjusting piece 42. The presser 36 is normally pressed against the front 47 of the punch by a spring 49, Fig. 5, acting on a lever 51, Figs. 5 and 11. The ejector 35 is pressed towards the punch against metal strip 8 by a spring 50 acting through a lever 52. The hammers 34 are actuated by an eccentric 56, Figs. 5 and 7, on shaft 10, which actuates lever arms 58 having set screws 62 at their free ends which engage the hammers. The feed finger 37, Fig. 7, is reciprocated vertically by means of a ball-bearing eccentric 64 on shaft 10, operating through a plunger 67 and a ball-bearing 66, the finger 37 being biased downwardly by a spring 65, and passing through a slot in punch 32. The drum 20, Figs. 16 and 17, for feeding the tape intermittently comprises outer and inner shells 72, 80, mounted on a stationary shaft 59. To inner shell 80 is attached an arm 84 carrying a roller 85 which co-operates with eccentric 40 and spring 88 to impart a rocking movement to the shell. A ratchet wheel 86 on shell 80, and a pawl 91 pivoted to shell 72 co-operate to impart a step-by-step movement to the latter and so to the tape 1 which is pressed against a knurled surface 76 on the outer shell by a spring band 93. To regulate the length of fastener produced, a toothed ring 98, Fig. 10, is driven by teeth 97 on the bottom edge of outer shell 72, and runs over a supporting roller 99 on a lever 100 which is pressed upwardly by a spring 101. Ring 98 has a thickened part 102 which, in the course of the rotation of the ring, depresses roller 99 and lever 100, moving a second lever 103, and a cranked lever 106, and pushing inwardly a rod 108 which blocks downward movement of feed finger 37, so stopping the feed of fastener elements to the tape, while feed of the latter continues. The ridge 102 also operates a feeler 110 which actuates a counter.