Slide fastener with thermoplastic end stops

Abstract: A slide fastener 10 includes an end stop (18) which is made of a thermoplastic material and allowed on melting by ultrasonic or high-frequency fusion to permeate yarns (11a) of fastener tapes (11), penetrate the interstices or openings (11b) in the tapes and fuse together at the confronting ends (18a′, 18b′) of the end stop with the tape (11) sandwiched therebetween thereby firmly anchoring the same in place against movement even under increased stresses.

Description: The present invention relates to a slide fastener according to the preamble of claim 1. DE-A-2 309 624 discloses a slide fastener of this type having coupling elements including upper and lower legs disposed on opposite sides of the corresponding stringer tape. These pairs of upper and lower legs have respective one end portions fused together and extending through pores in the stringer tape. An upper end stop of a non-metallic material may be secured to the corresponding stringer tape in a similar way. It is to be noted, however, that the end stop is placed between adjacent coupling elements. Such conventional end stops are, however, not entirely satisfactory in that their bondage to the fastener is reduced particularly where the fastener tapes are formed by different, relatively long filament yarns which present a slippery tape surface. Other difficulties of the prior art devices are found in that when end stops are attached to woven or knitted tapes having surface irregularities, the thermoplastic resin of the end stops tends to produce objectionable burrs or fins which would not only mar the product value but also present a fear for physical injury to the user, and in that when end stops are applied only to one side of the tape, their anchorage thereto is insufficient to withstand impinging forces exerted by the slider. DE-A-27 52 703 discloses a slide fastener of the type according to the preamble of claim 1. In this conventional slide fastener the upper and lower wings of the end stop serves to protect the serving thread and do not extend beyond the connecting portions of the coupling elements. The present invention seeks to provide improved end stops for slide fasteners which will eliminate or alleviate the foregoing difficulties of the prior art devices. This object is realized by the basic concept of the invention set forth in the characterizing portion of claim 1. Further developments of the invention will now be described in more detail with reference to some preferred embodiments thereof illustrated in the accompanying drawings, in which Figure 1 is a fragmentary perspective view on enlarged scale of a slide fastener stringer to which a top end stop embodying the invention is applied at its top end; Figure 2 is a plan view partly cut away of the slide fastener stringer of Figure 1; Figure 3 is a plan view of a slide fastener having end stops of the invention applied at both its top and bottom ends; Figure 4 is a perspective view of a starting form of a top end stop according to the invention; Figure 5 is a perspective view of another form of a top end stop according to the invention; Figure 6 is a fragmentary plan view of a modified slide fastener tape to which the top end stop of the invention is applied; Figure 7 is a view similar to Figure 6 but showing another form of tape to which the inventive top end stop is applied; Figure 8 is a transverse cross-sectional view of a knit fastener tape to which the inventive top end stop is applied; Figure 9 is a fragmentary plan view showing the top end stop applied to a modified form of fastener stringer; and Figure 10 is a transverse cross-sectional view taken on the line X-X of Figure 9. Referring now to the drawings and firstly to Figure 3, there is shown a slide fastener 10 which comprises a pair of identical stringer tapes 11, 11 each carrying a continuous row of coupling elements 13 along its inner longitudinal edge 14, the coupling elements 13 being secured to the tape edges as by sewing threads 15 as better shown in Figures 1 and 2. A slider 16 has a pull tab 17 with which the slider is normally moved along the rows of coupling elements 13 in one direction to open and the other direction to close the slide fastener 10 in a manner well known in the art. The reciprocal movement of the slider 16 in a direction to close the fastener 10 is limited or stopped at the top end of the fastener 10 by a pair of top end stops 18, 18 as the slider flanges 16a (shown in Figure 2) are brought into abutting engagement with the respective end stops 18. Movement of the slider 16 in a direction to open the fastener 10 is limited or stopped at the bottom end of the fastener 10 as it comes into contact with a bottom end stop 20. Figure 4 shows a starting form of the top end stop 18 made of a thermoplastic resin such as polyester, polyamide or the like which initially assumes an elongated monofilamentary strip 19 of predetermined width and thickness. This elongated strip is cut to a predetermined length as along the dotted-line and centrally folded on itself to provide a substantially U-shaped staple-like end stop blank 18′ having an upper leg 18a and a lower leg 18b interconnected by a rounded corner 18c. Another starting form of top end stop 18 is shown in Figure 5 as designated at 19′, which is a profile cut to provide a U-shaped end stop blank 18′ identical to that of Figure 4. The U-shaped blank 18′, as shown in Figures 1 and 2, is mounted astride the edge 14 of a woven tape 11 in close proximity to a terminal one of the coupling elements 13, and anchored in place by ultrasonic or high-frequency fusion of the material of the blank 18′ while the latter is molded into a final shape free of burrs or fins, in which instance the upper leg 18a is deformed with its end portion 18a′ pressed against confronting end portion 18b′ of the lower leg 18b which lies straight against and in parallel with the plane of the tape 11. The blank 18′ envelops therein the sewing threads 15 together with the tape edge 14 when it is mounted on the latter. This deforming action causes individual yarns 11a of the tape 11 to spead apart to provide openings 11b of widened interstices or pores through which the molten resin material of the blank 18′ penetrates and adhesively join the confronting ends 18a′, 18b′ of the respective legs 18a,18b to provide the top end stop 18. Ultrasonic processing as applied in Figures 1 and 2 creates a hammering action which is transmitted through the blank 18′ to the woven tape 11, to cause woven yarns 11a to spread apart thereby to provide desired openings 11b. Figure 6 shows a fastener stringer tape 11 having bores 11c which are preformed as by punching and which should be peripherally fused to avoid frays, the bores 11c being utilized for the passage of molten resin of the blank 18′. The openings 11 b for the same purpose may be formed by providing the weave of the tape 11 with a coarse interstice portion 11d as shown in Figure 7 or by inserting heated pin tools into the interstices to spread permanently the same. Figure 8 shows a top end stop 18 mounted on a knitted tape 11 having alternate wales 21a and grooves 21b in which instance the ends 18a′ and 18b′ of the end stop blank 18′ are confronted across the groove 21b which has coarse interstices serving as openings 11 b for the penetration of the molten resin of the staple 18′. Figure 9 shows the top end stop 18 mounted directly over the coupling elements 13 and fused in place together therewith as shown in Figure 10. According to the invention, the top end stops 18, 19 and the bottom end stops 20 alike can be securely anchored in place on the fastener tapes 11, 12 against displacement on impinging contact with the slider 16, this being accomplished by the adhesive system in which the thermoplastic resinous material constituting the end stops is allowed on melting to permeate the yarns of the tapes, penetrate through their interstices or openings 11b and fuse together at the confronting ends of the end stops.

Claims: A slide fastener (10) comprising: a pair of slide fastener stringers each having a stringer tape (11) and a continuous row of coupling elements (13) mounted with serving threads (15) on and along an inner longitudinal edge (14) of each stringer tape, a slider (16) slidably mounted on the two rows of coupling elements (13) to take them into and out of interdigitating engagement with each other to close and open the slide fastener (10); and an end stop (18,20) of thermoplastic synthetic resin including upper and lower wings (18a, 18b), each disposed on an opposite face of one of said stringer tapes (11) and enveloping at least one end of said row of coupling elements, said end stop (18,20) being attached to at least one of said stringer tapes by fusion enveloping thereby one end of said row of coupling elements (13) including said serving threads (15), characterized in that said stringer tape (11) has a porous structure, and in that said wings have respective end portions (18a′, 18b′) extending through pores (11b) in said stringer tape (11) and fused together. A slide fastener according to claim 1, wherein said stringer tapes (11) include coarse interstice portions (11d) extending along the respective inner longitudinal edges (14), and said end portions (18a′, 18b′) of said wings (18a, 18b) are disposed on said coarse interstice portions (11d). A slide fastener according to claim 1, wherein said stringer tape (11) is a knit tape, and said one end portions of said wings are fused together through openings of said knit tape at grooves (21b) disposed between adjacent pairs of wales (21a) of the same.

Inventors: FUJISAKI YOSHINORI, KONDO NAOKI, FUJISAKI, YOSHINORI, KONDO, NAOKI
Applicants: YOSHIDA KOGYO KK, YOSHIDA KOGYO K.K.
Application year: 1987
Main classification: A44B19
IPC codes: A44B19