Patent GB-651437-A (GB)
Title: Improvements in or relating to machines for casting sliding clasp fastener elements on stringer tapes
Filed: 1948-06-26
Abstract: 651,437. Casting fastener elements. PLASCO, Ltd. June 26, 1948, No. 17257. Convention date, Oct. 11, 1947. [Class 83 (i)]  A. machine for casting sliding clasp fastener elements on to a stringer tape, including means for spacing the stringer lengths one from the other along the tape, which has spliced portions where two tape ends are joined, is characterized by electric feeler mechanism in front of the casting dies and operating to produce a wide spacing of the stringer lengths at a spliced portion. At the upper part of the machine frame are dies 18, 18<SP>1</SP>, Fig. 1, carried by rods 17 and 171 and moved towards and away from each other by air cylinders 16, 16<SP>1</SP>. Below the dies is a driven shaft 20 which drives through gearing  a rotary valve 25 controlling the supply of compressed air for operating various parts of the machine and also drives a gear 33, Fig. 2, so that the valve 25 and its shaft 75 rotate thirty times for one revolution of the gear 33 which is rotatably mounted on a shaft 30 which may be driven therefrom by a clutch 34. On the polygonal end 46' of the shaft 30 is a disc 47 formed with an arcuate channel 48 co-operating with a port 44 in a fixed member 42 so that as the disc rotates, air may pass from a supply pipe 51 to an outlet pipe 45 leading to the gooseneck of the casting apparatus during the greater portion of the revolution of the shaft. During this portion, the fastener elements are cast on to the tape, the non-channelled portion of the disc 47 corresponding to a space of four cast elements. On the energizing of a solenoid 41, an arm 40 actuates a catch allowing the shaft 30 to be driven for one complete revolution, after which the clutch is again disengaged. The shaft 78 carries two cams 76 and 77 which operate valves 74 and 75, (Fig. 12) inserted in the air supply line between the rotary valve 25 and the disc 47 and also carries a worm 85 serving to drive through a ratchet device, an endless chain 63, Fig. 10, to which pairs of trip blocks 84 may be secured. The end of the shaft 30 opposite the disc 47 carries a cam 57 operating a valve 58 controlling the supply of compressed air to one side or the other of a piston 60 secured to a finger 62 which is adapted to engage beneath a pair of blocks 84 and move the chain 63 against its ratchet device from the full to the dotted line position shown in Fig. 10. In the latter position, the blocks actuate a link 82 so as to move an arm 80 out of a slot 81 in the valve 74 so that the valve may move into closed position and into engagement with the cam 76. The stringer tape 19 on which the elements are to be cast passes through feeler mechanism 101 on its way to the die members 18, 18<SP>1</SP>. Lengths o. tape are joined by means of a splicing 92 which is slotted as at 111, Fig. 13. The feeler mechanism comprises two rollers 109, 110 adapted to bear on the upper surface of the tape, one, 109, being in such a position that it will project through any slot 111 and actuate the pin 107 of a switch 103, while the other roller 110 will actuate the pin 108 of a switch 104 when a tape end is reached. In operation, assuming the machine to be casting elements on to the tape when a spliced portion passes the feeler mechanism, the roller 109 will operate switch 103 and solenoid 41 to engage clutch 31 to begin the rotation of the shaft 30. Casting of the elements continues for another twenty-four elements until the blank portion of the disc 47 cuts off the passage of air from pipe 51 to the pipe 45 leading to the gooseneck. At this instant the cam 57 moves valve 58 to admit air to the plunger 60 so that the finger 62 moves two blocks 84 into the upper position shown in Fig. 10, thus shutting off air from the gooseneck for two complete cycles of the shaft 30 by closing valve 74. The clutch is then disengaged to stop the shaft 30 and the operation of the machine continues normally. The actuation of the roller 110 by the end of a tape length serves to stop the machine. Specification 605,203 is referred to.