Patent GB-1479997-A (GB)
Title: Manufacture of slide fastener control slide stop studs
IPC: A44B19/60
Filed: 1975-03-06
Abstract: 1479997 Sliding clasp fasteners SOC PRESTIL SA 6 March 1975 [12 March 1974] 9333/75 Heading E2S A method of making stop studs for the control slide of slide fasteners comprising coupling elements 5 in each row made of plastics filament forming a sequence of sinuous configurations such as helices or meanders, said filament being applied according to the type of elements either on a single face of the corresponding carrier tape 2 or straddlewise on both faces thereof, is characterised in that said stop studs are formed on one face of the carrier tapes 2, 2 by combining an additional external supply of plastics material to said one face with a partial flow, through the tapes, of plastics material constituting initially the coupling elements registering with each other on the other face of said tapes, and that, in the case of a helix-type slide fastener, said additional external supply of plastics material is applied to the faces opposite those carrying said elements. According to the invention also the said application is carried out jointly with the application of pressure and localized heating or, instead of said heating, with the action of supersonic vibration in order to cause the plastics material of said coupling elements located on said other faces of said tapes to melt and flow through the texture of said tapes. As shown, a continuous fastener chain 8 with coupling elements 5 in the form of a plastics helical filament 1 secured to one face 2 of each carrier tape 3 of woven form, is fed, at intervals, in the direction F 3 , Fig. 1, with its plain face 4 uppermost, along an anvil 7. During each stationary period of the chain 8 an end portion of a plastics rod 12 is fed from a device 13 across the chain in the direction F 3  whereupon a heated punch 6 is lowered onto the chain, the punch 6 having a sharp ridge 11 adapted to form a slit between the two moulded stop studs, and two cavities 10 into which the rod material is pressed to form the pair of stop studs 14 on the top surfaces 4 of the tapes 3. The tool 6 also melts the turns of the filaments therebeneath which, due to the pressure of the tool, seeps through the interstices, and meshes, of both of the tapes 3 in the form of irregular streamlets 15, Fig. 4, which thoroughly mix with the rod material. The melted turns of filament remaining on the under face 2 of the tapes 3 form small plates 16- which are integral with the streamlets 15 and provide a riveting-type anchorage of the stop studs 14. The descending tool 6 first cuts off the rod end portion and then forms a slit between the two plates 16. The tool ridge 11 may be replaced by a shaped configuration, Fig. 6, to provide an oval recess 20, Fig. 6, which has a duct, not shown, to carry off excess plastics material. The same procedure is carried out for tapes with meander-type filaments (1a, 5a) which straddle the edges of the tapes (3a, 3a) Figs. 11-15, not shown. The localised heating of the tool may be replaced by the action of supersonic vibration; the tape ends may be bone perforations formed therein; and the cutting ridge 15 may be omitted from the tool when the fastener chain is fed across the anvil in an open condition. The melting points of the filaments 1 and the rod 12 should preferably be closely related.