GB2046829A

GB2046829A - Slide fastener stringer and method and apparatus for its manufacture

Info

Publication number: GB2046829A
Application number: GB8007128A
Authority: GB
Original assignee: HEILMANN OPTILON; Optilon W Erich Heilmann GmbH
Current assignee: HEILMANN OPTILON; Optilon W Erich Heilmann GmbH
Priority date: 1979-03-01
Filing date: 1980-03-03
Publication date: 1980-11-19
Also published as: JPS55151906A; DE2907902A1; FR2450076A1; GB2046829B

Abstract

The stringer 1 comprises a textile support tape 5 carrying a series of U-shaped thermoplastics fastener members 2, the limbs of each member 2 being welded at least partially to each other through apertures positioned between an edge bead 3 and a parallel longitudinal bead 4, and also being at least partially welded to elements 11 of the support tape 5 disposed between these apertures. The fastener members are initially formed as a ladder-like structure comprising straight fastener members 2 with opposite ends interconnected either by permanent textile support strands or a removable support strip. This structure is bent into U- shape by apparatus comprising a blade held in a forming die in a driven forming wheel. Welding studs between the limbs of the fastener members are heated to welding temperature through contact with the heated blade and are pressed, by the combined action of the blade and forming die, against the opposite sides of the support tape 5. <IMAGE>

Description

SPECIFICATION Slide fastener stringer and method and apparatus for its manufacture This invention relates to a slide fastener stringer of the type comprising a textile support tape carrying a series of generally Ushaped fastener members made of thermoplastics material, the support tape including an edge bead which serves as a longitudinal core extending along coupling eyes defined between the limbs of the fastener member which are mounted astride this longitudinal core. The invention also relates to a method of, and apparatus for, manufacturing such a slide fastener stringer and to a slide fastener incorporating such slide fastener stringers.

With known slide fastener stringers of this type (German OLS 27 22 054), the textile core is an independent component on which the fastener members, bent into U-shape, are mounted. There are also provided four support strands embedded in the limbs, with two strands embedded in the limbs, with two strands in each limb of the individual members. The series of members thus constructed comprise an independent string which is combined with the support tapes during the weaving or knitting thereof, with the filler cores and support strands covered only by tape weft yarns. No tape warp yarns run between the member limbs. This construcion presents difficulties from the manufacturing aspect, since the series of members with their filler core and support strands must be fed into the loom or knitting machine during the weaving or knitting of the support tape.When such a 'foreign body' is introduced, the loom or knitting machine can only operate at a reduced working rate. There are also functional disadvantages. For instance, if the finished fastener is subjected to transverse tension, the core and the support strands must withstand the entire transverse tensile forces, and these are applied at individual points where they cause very high shear loads. In relation to the considerable transverse tensile strength of the tape considered per se, the transverse tensile forces that can be accepted by the fastener are relatively small. The structure of the tapes and the binding-in can also be changed under lateral tension. For these and other reasons, with known slide fasteners of the type described, the individual members in the series can be twisted relative to the plane of the tape about an axis parallel to the longitudinal axis of the fastener.The bond of the fastener members with the tapes is not sufficiently torsion resistant. If such twists occur when the fastener is open, for instance while an attached garment is being cleaned, it can no longer be properly opened by operating the slider. If the twist is permanent, the transverse tensile strength is seriously affected through bending out of the fastener plane. Known fasteners of the type described are therefore very sensitive to transverse tension and torsion. With fasteners of this type, proposals have of course been made to improve the torsion resistance of the members in relation to the tapes, for example by arranging a groove at the feet of the members, with a separate foot filament laid into the grooves.

However this merely increases manufacturing problems and does not result in sufficiently improved torsion resistance for the slide fastener to withstand considerable transverse tensile forces.

In addition it has long been known in practice to use injection moulding machines and dies to mould slide fastener members onto, or astride, a support tape which for this purpose is fed through the dies. This has not hitherto affected the development of slide fasteners of the kind to which this invention relates, and can also only be carried out if the actual fastener members are themselves relatively coarse sized. However in practice slide fasteners are required to be as delicate as possible, especially in the clothing trade, and this also necessitates slide fasteners having fastener members which are as delicate as possible.

This invention is primarily concerned with the problem of further developing slide fasteners of the type described to improve their transverse tensile strength by improving the attachment of the fastener members to the support tapes, whilst additionally providing a fastener construction which is capable of highspeed manufacture by a simple method and using a simple apparatus.

To solve this problem the invention teaches that the core comprises an eddge bead of the support tape, the support member comprises a longitudinal bead of the support tapes with a gap separating the edge bead and the support member, at least in this separation gap the support tape has welding apertures, and the limbs are at least partially welded to each other through the welding apertures in the separtion gap between the edge bead and the longitudinal bead on the tapes, and are at least partly welded to elements of the support tape lying between the welding apertures.

The invention is based on the recognition that the sensitivity to transverse tension associated with known slide fasteners of the type described, together with the deficient torsion strength of individual members, can both be avoided if the core and the support member are both completely integrated with the tape from the weaving and knitting aspects, that is they constitute an edge bead and a longitudinal bead of the support tape.

This means that the support tapes thus constructed must be pre-manufactured. Additionally, the fastener member limbs are not only joined to each other but also to elements of the support tape disposed between the welding apertures. As a result, the transverse tensile forces no longer occur as localised forces jointly stressing the core and the support strands in shear; instead they are distributed over the tapes as a whole, and as a whole stabilise the fastener members against torsional movement.

Particularly high transverse tensile strength and torsional stability are achieved with an embodiment of the invention in which the fastener members have portions of their limbs projecting beyond the support members away from the side of the support tape. With this embodiment the area of the support tape covered by projecting limb portions also has -welding apertures,- and the projecting limb portion are at least partly welded to each other through these welding apertures and also to the tape elements disposed between these welding apertures. "At least partly welded" means a positive bond between the climb sections and/-or with the support tape, which might also be considered as a weldedon, or laminated, construction.To ensure the weld joint is particularly effective and at the same time to provide extra support for the core when subjected to transverse forces, the limbs preferably have welding studs between which the support member recesses are disposed, and the welding studs also constitute transverse stress abutments for the core positioned in the coupling eyes As regards the forrn of the support tapes, there are various possibilities swithin the scope of the invention. Thus the tapes -can consist of veryn finely woven or knitted fabrics wherein the welding apertures are stamped out.However, in one preferred embodiment of the invention, the welding apertures comprise the stitchloop interstices in a correspondingly coarse-looped -woven of knitted fabric, with the size of the interstice for example being about one fifth of the width of the members longitudinally of the support tape. With this embodiment an adequate band is obtained between the fastener members and tape -ele- ments dying between the welding apertures merely if one warp member or a row of stitches is positioned approximately centrally in the gap separating the edge bead and the longitudinal bead and/or -in the area of the projecting portions.

The series of fastener members can be made in known manner, for instance as taught by German OLS 2722054 or German 01L5 1610325, with the result that at least one iongitudinally-extending auxiliary tensile member is also embedded in the limbs, preT- erably above the gap between the edge bead and the tlongitudinal bead. lziowever, the con necting strands together with the fastener member blanks may also be formed from thermoplastic material, with the fastener .mem- ber blanks divided into fastener members ei- ther during or after the bending process, with the auxiliary strands preferably formed on the fastener -members at the foot side.

The advantages achieved in a slide fastener according to the invention are that, due to the distribution of transverse tensil forces and due to the co-operation of the tapes, very high transverse tensile forces can be suppoorted, and harmful twisting of the individual fastener members relative to the plane of the tape is prevented. This applies especially when using tapes having both longitudinally and transversely extending synthetic yarns and/or edge and longitudinal beads having synthetic yarns, with these synthetic yarns shrunk by heatseting. The heat-setting can be used for fur ther -improving the transverse tensile strength and torsion resistance.To achieve this, the heat-setting is performed on the finished slide fastener stringers equipped with their series of coupling members, and in the area of the attached fastener members the tape components are consequently braced in relation to the fastener members. It is especially advantageous that slide fasteners in accordance with the invention can be very easily produced, since it is no longer subsequently linked with the tapes in the course of a tape weaving or knitting process.

T:he invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which Figure 1 is an enlarged plan view of a section of slide fastener in accordance with the invention; Figure 2 is a transverse section taken along the line A-A in Fig. 1; Figure 3 is an enlarged plan view into the same scale as Figs. 1 and 2 of a ladder-like structure for use in manufacturing a slide fastener stringer in accordance with the invention; Figure 4 is a section taken along the line B-B in Fig. 3; Figure 5 is a transverse section similar to Fig. 2 but illustrating the assembly of the ladder structure of Figs. 3 and 4 with a preformed support tape; ; Figure 6 is a side elevation of apparatus for performing the method in accordance with the invention, and fires 7-9 are sections taken respectively along the lines G-C, D--D, E-E in Fig. 6.

The slide fastener shown in Figs. 1 and 2 -'comprises a pair of fastener stringers 1 which each consists basically of a row of thermoplastic fastener members 2 bent into U-shape, a longitudinal textile core 3, at least one support member 4 formed as a textile strand, and a support tape 5 of woven {or knitted) con Struction Each fastener -member 2 has a cou pling h-ead 6 with a coupling eye 7 between a pair.of iLirnbs 18 The textile core 3 is positioned in the coupling eyes 7, with the sup port member 4 between the limbs 8. Obviously the slide fastener will include a slider, for opening and closing the fastener stringers in the normal manner, but this forms no part of the invention and hence is not shown.

Similarly the fastener stringers would be provided with the usual top and bottom stops.

From Figs. 1 and 2 it will be seen that the textile core 3 is formed as an edge bead separated by a gap A from the support member 4 which is formed as a longitudinal bead along each support tape 5. At least in the area of this gap A, the support tapes 5 have interstices forming welding apertures 9. The support members 4 are disposed in corresponding recesses 10 on the inner faces of the limbs 8. The limbs 8 are at least partly welded to each other through the welding apertures 9 in the gap A separating the edge bead 3 from the longitudinal bead 4 in the tapes 5, and are at least partly welded to support tape elements 11 disposed between the welding apertures 9.

The illustrated embodiment of slide fastener stringer therefore has sections of limbs 1 2 projecting on the tape side from the individual members 2 or their limbs 8. In the area of these projecting limb sections 1 2 the tapes 5 are also provided with interstices forming welding apertures 9, and the projecting limb sectins 1 2 are also at least partially welded to each other through the welding apertures 9, in the manner described, and also to support tape elements lying between the welding apertures 9.The embodiment also shows the construction of a slide fastener stringer in accordance with the invention (see Fig. 4 also) wherein the limbs 8 have welding studs 1 3 between which lie the support strand recesses 10; these welding studs 1 3 also act as transverse abutments for the cores 3 disposed in the coupling eyes 7.

Fig. 2 in particular shows that the welding apertures 9 may be stitch interstices in a correspondingly coarse-looped woven or knitted fabric, with the size of the interstices in this embodiment about one fifth of the width B of the fastener members 2 longitudinally of the stringers 1. The support strand 4 is positioned approximately centrally in the gap A between edge bead 3 and the bead 4 and/or in the area of the projecting limb sections 1 2.

Fig. 5 shows that at least one longitudinal auxiliary support member, in the form of a textile strand 14, can also be embedded in the limbs 8, preferably above the already mentioned gap A separating the edge bead 3 and longitudinal bead 4.

The support tapes 5 can also be of the type in which both the longitudinal and transverse elements comprise synthetic yarns and/or edge and longitudinal beads 3, 4 including synthetic yarns, so that these synthetic yarns can be shrunk by heat-setting. The finished tapes 5 equipped with the series of fastener members 1 are then heat-set with the result that, in the area of the attached members 2, the tape elements are braced against the fastener members thereby increasing their transverse members thereby increasing their transverse tensile strength and resistance to torsion.

Figs. 3-5 also serve to indicate a method for making a slide fastener stringer in accordance with the invention. A ladder-like structure is first made in known manner, with straight fastener members 2 not yet bent into U-shape, comprising the rungs, and with connecting strips 1 5 attached to their limbs 8.

the straight members 2 are subsequently bent into U-shape and, during this bending, the longitudinal core 3 is inserted into the coupling eyes 7. The connecting strips 1 5 may consist of the same material as the members 2 themselves, or may be textile strands embedded in the limbs 8 of members 2.

In any case, the straight members 2 are heated to welding temperature on their inside face, at least in the area of the limbs 8, and are then forced into a bending die 16, which is preferably heated, along a bending track 23 as shown in Figs. 7-9. Along the bending track 23 the die 1 6 progressively forces the limbs 8 into a U-shape and finally welds then together. In the region of the bending track 23, the tape 5 is inserted between the limbs 8 of the fastener members and is gripped thereby and onwardly conveyed (under slight tension) during the welding operation.

In general, the fastener members 2 are inserted ino the bending die 1 6 by a heated bending blade 17, whose thickness decreases along the bending track 23. The support tape 5 is progressively fed between the limbs 8 as the thickness of the bending blade 1 7 reduces. For this purpose it may be desirable to pre-heat the support tape 5.

The re-forming device 18, shown in Figs.

6-9 for performing the described method also forms a subject of the invention. Firstly an unshown worm press extrusion press and a forming wheel generate the ladder-like structure. The reforming device 1 8 includes a heating roller 1 9 and a shaping roller 20 with a grooved peripheral forming die 1 6. The two rollers 19, 20 have a transfer zone 21 formed between them so that the ladder-like structure is fed along an arcuate heating track 22 around the heating roller 19, and through the transfer zone 21 to the shaping track 23 on the shaping roller 20.

The bending blade 1 7 is positioned next to the transfer zone 21 and has a beinding face 24 which is arcuate and enters the forming die 16. The back face 25 of blade 17 has a tape feeder 26 mounted thereon so that the support tape 5 can be fed tangentially into the forming die 16.

The heating roller 1 9 preferably has a plain cylindrical heating surface, ie it is not pro vided with recesses for the fastener members or the rungs of the ladder-like structure, though it may be roughened. The heating roller 1 9 does not need a separate drive, and can be entrained by the movement of the ladder-like structure, whilst the shaping roller 20 is positively driven. Preferably the temper ature of the shaping roller 20 and the tape feeder 26 can be controlled to enable the welding process to proceed without difficulty.

The forming die 1 6 may also constitute the welding tool, if as represented it is so designed that during bending operations the limbs 8 of the fastener members 2, or else the welding studs 1 3 formed thereon, can be forced together at a pressure suitable for welding. The shaping roller 20 is preferably followed directly by a standard heat-setting device.

Claims

1. A slide fastener stringer comprising a textile support tape carrying a series of generally U-shaped fastener members made of ther moplastics material, the support tape includes an edge bead which serves as a longitudinal core extending along coupling eyes defined between the limbs of the fastener members, the support tape also includes at least one support member defining a longitudinal bead separated from the edge bead by a gap, the support tape has welding apertures at least in the region of said gap, and the limbs of each fastener member are mounted astride the edge bead and the longitudinal bead and are at least partially welded to each other through the welding apertures in the region of said gap and are also at least partially welded to elements of the support tape disposed between the welding apertures.

2. A slide fastener stringer, according to Claim 1, in which the limbs of each fastener member are provided with recesses for receiving the support member of members.

3. A slide fastener stringer, according to Claim 1 or 2, in which sections of the limbs project beyond the support member away from the edge bead, the support tape has weld apertures positioned between these projecting limb sections, and the projecting limb sections are at least partially welded to each other through these welding apertures and are also at least partially welded to elements of the support tape disposed between these welding apertures.

4. A slide fastener stringer, according to any preceding Claim, in which the limbs have welding studs between which recesses are provided for receiving the support member of members, and these welding studs constitute transverse stress abutments for the longitudinal core extending along the coupling eyes.

5. A slide fastener stringer, according to any preceding Claim, in which the welding apertures are provided by interstices in a coarse woven or knitted textile support tape, and with the welding aperture being about one fifth of the width of the fastener members longitudinally of the stringer.

6. A slide fastener stringer, according to any preceding Claim, in which a warp member or a row of stitches is disposed substantially centrally in the gap between the bead edge bead and the longitudinal bead.

7. A slide fastener stringer, according to any preceding Claim, in which a longitudinally directed auxiliary support member also interconnects the limbs.

8. A slide fastener stringer, acording to Claim 7, in which the auxiliary support member is positioned above the gap between the edge bead and the longitudinal bead.

9. A slide fastener stringer, according to any preceding Claim, in which the support tape includes both longitudinally-directed and transversely-directed synthetic yarns or threads, and these synthetic yarns or threads are shrunk by heat-setting after the fastener members have been secured to the support tape whereby the support tape is braced against the fastener members.

1 0. A slide fastener stringer substantially as described herein with reference to and as shown in Figs. 1 to 5 of the accompanying drawings.

11. A method of manufacturing a slide fastener stringer in accordance with any of Claims 1 to 10, including producing a ladderlike structure having straight fastener members as the rungs which are interconnected by support members or support strips, continuously bending the straight fastener members into the requisite U-shape, inserting the longitudinal core of the support tape between the limbs of the fastener members as they are being bent so that the longitudinal core is positioned adjacent the coupling eye, heating at least the mutually facing portions of each pair of limbs to welding temperature, and subsequently forcing the limbs against the opposite sides of the support tape to achieve the welding.

1 2. A method, according to Claim 11, including progressively forcing the straight fastener members into a bending die and subjecting the support tape to a slight tension during the welding operation.

1 3. A method, according to Claim 11 or 12, including heating the support tape before its insertion between the limbs of the fastener members.

14. A method of manufacturing a slide fastener stringer in accordance with any of Claims 1 to 10, substantially as described herein with reference to Figs. 3 to 9 of the accompanying drawings.

1 5. A slide fastener stringer manufactured by the method of any of Claims 11 to 14.

1 6. A slide fastener comprising slide fastener stringers according to any of claims 1 to 10 or 15.

1 7. Apparatus for manufacturing a slide fastener stringer in accordance with the method of any of Claims 11 to 14, including means for reforming the ladder-like structure comprising a heating roller and a shaping roller having a peripheral groove defining a forming die, the ladder-like structure being conveyed along an arcuate heating track around the heating roller, then through a transfer zone and along a shaping track around the shaping roller, a bending blade positioned adjacent the transfer zone having a bending face which is generally arcuate and extends into the forming die progressively to bend the fastener members into the requisite U-shape, the bending blade also having a back surface which converges towards the bending surface, and a support tape feeder arranged to insert the support tape generally tangentially along the back surface into the forming die.

18. Apparatus, according to Claim 17, in which the heating roller has a plain cylindrical heating surface and is entrained by the ladderlike structure which is pulled by a driven shaping roller.

1 9. Apparatus, according to Claim 1 7 or 18, in which the shaping roller and the tape feeder are controlled to provide the required degree of welding.

20. Apparatus, according to any of Claims 1 7 to 19, in which the forming die cooperates with the end of the bending blade to serve as a welding tool for pressing the mutually facing surfaces of each fastener member against the support tape.

21. Apparatus, according to any of Claims 1 7 to 20, including a heat-setting device to receive the stringer leaving the forming roller.

22. Apparatus for manufacturing a slide fastener stringer in accordance with the method of any of Claims 11 to 14, substantially as described herein with reference to Figs. 6 to 9 of the accompanying drawings.