GB1577813A

GB1577813A - Slide fastener stringer

Info

Publication number: GB1577813A
Application number: GB2527677A
Authority: GB
Original assignee: Textron Inc
Current assignee: Textron Inc
Priority date: 1976-07-19
Filing date: 1977-06-16
Publication date: 1980-10-29
Also published as: AU2635477A; JPS5311645A; AU508211B2; CA1069279A; DE2730540A1; BE856833A

Description

(54) SLIDE FASTENER STRINGER (71) We, TEXTRON INC., a corporation organised and existing under the laws of the State of Delaware, United States of America, of 40 Westminster Street, Providence, Rhode Island, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us. and the method by which it is to be performed, to be particularly described in and by the following state ment:- In commercially available slide fastener stringers utilising a continuous coupling element such as a spiral coupling element secured to one edge of a carrier or support tape, the continuous coupling element is usually secured to the edge of the tape by sewing or by weaving the coupling element to the tape.

Slide fasteners have been proposed having continuous coupling elements secured within a folded support tape wherein head portions of the coupling element extend from slits between straps forming the folded edge of the tape, but such fasteners have not been used significantly commercially despite the obvious cost advantage of using low-cost strips such as synthetic polymer or paper strips for the support tape compared to woven textile tapes. This lack of commerical use can be due for example to breakage or tearing of the straps, poor support for or instability of the coupling element, inability of the stringer to withstand high slider forces, and excessively difficult slider operation.

This invention relates to slide fastener stringers of the type (herein referred to as stringers of the type specified) comprising a support tape folded to provide a folded edge and formed with a plurality of spaced slits transverse to and extending from the folded edge to define a series of straps, and a continuous filament coupling element comprising a plurality of coupling sections each with a head extending from a respective slit in the tape and an interconnecting portion connecting the section to an adjacent coupling section, the interconnecting portions extending within-the straps, and the folded portions of the tape being secured together on the side of the interconnecting portions remote from the folded edge.

Examples of such stringers are described and claimed in our Patent Specifications Nos.

1492908 and 1492909. The inventions described and claimed in these specifications may be utilised in conjunction with the present invention.

According to this invention, in a stringer of the type specified the coupling element has a thickness to form a bead along the folded edge of the tape, and further has a bearing for engagement by a slider for the fastener formed by securing a cord or cords to the external surface of the folded tape to extend longitudinally alongside the bead.

The invention enables a low cost and reliable slide fastener to be produced which has a reduced tendency for tearing of the straps. Also easier operation of the slider of a fastener having stringers as set forth may be obtained.

An advantage of the stringer of this invention is that the provision of the cord or cords on the outside of a folded tape increases the ability of the stringer to withstand high slider loadings, eases slider operation and increases the life of the slide fastener.

Other objects, advantages and features of the invention will be apparent from the following description of a preferred embodiment taken in conjunction with the accompanying drawings.

In the drawings, Fig. l is a partial plan view of a slide fastener in accordance with the invention.

Fig. 2 is an enlarged plan view of a portion of one stringer broken away from the slide fastener of Fig. 1.

Fig. 3 is a cross-section view of the stringer portion of Fig. 2 Fig 4 is a side view with parts broken away of the stringer portion of Figs. 2 and 3.

Fig. 5 is a view similar to Fig. 2 of a stringer portion of a modified slide fastener in accordance with the invention.

Fig. 6 is a plan view of an unfolded strip for forming the folded tapes in the fasteners.

Fig. 7 is a cross section view of the modified stringer portion of Fig. 5.

Fig. 8 is a cross section view of another modified stringer portion in accordance with the invention.

Fig. 9 is a cross section view of still another modified string portion of a slide fstener in accordance with the invention.

As illustrated in Fig. 1, the invention is embodied in a slide fastener having planarly disposed support members such as tapes indicated generally at 10 and 12 and having continuous coupling elements such as spiral coupling elements indicated generally at 14 and 16 along with a slider indicated generally at 18 which is is slidable along the coupling elements 14 and 16 for opening and closing the slide fastener. The tape 10 and the coupling element 14, as viewed in Fig. 1, form a left stringer while the tape 12 and the coupling element 16 form a right stringer. The right stringer is substantially a mirror image of the left stringer.

The spiral coupling elements 14 and 16 are formed into successive convolutions or sections from a continuous filament, such as a nylon or polyester filament, which has an oblong cross section, such as a D-shaped cross section. As shown in Fig. 2 and 3 each convolution of the coupling element 14 includes a head portion 20, an upper leg portion 22 extending from the upper side of the head portion 20, a lower leg portion 24 extending from the lower side of the head portion 20, and a connecting or heel portion 26 interconnecting the lower leg portion 24 to the upper leg portion of an adjoining convolution.

The tape 10 is formed from a strip 27, Fig. 6, which has a longitudinal row of transverse slits 28 formed in an intermediate section thereof to define strap portions 30 extending between opposite strip portions or halves of the strip. As shown in Figs. 2-4, the strip is longitudinally folded along the row of transverse slits with the coupling elements 14 assembled inside of the fold such that the head portions 20 and the leg portions 22 and 24 protrude from the respective slits 28 with the interconnecting portions 26 extending within the fold beneath the strap portions 30.

The opposite portions or halves of the folded strip are secured together by suitable means, such as adhesive, ultrasonic or thermal bonding to secure the coupling element 14 in the folded edge of the support member 10.

The strip 27 forming the tape 10 is preferably a low cost material such as a synthetic polymer resin, paper or the like.

The slits 28 are formed in an oblique angle to the folded edge of the tape 10 so that the leg portions 22 and 24 of each section extend into opposite halves of the respective slit 28 at points spaced longitudinally along the folded edge of the tape 10.

The monofilament forming the spiral coupling element 14 is twisted such that the longest dimensions of the oblong cross sections of each pair of leg portions 22 and 24 are substantially aligned with each other and with the slits 28 where the leg portions 22 and 24 exit from the slits 28. The strap portions 30 are substantially wider than the slits 28 and extend generally perpendicular to the interconnecting portions 26.

As shown in Fig. 3, the thickness of the monofilament forming the coupling element particularly within the interconnecting portions 26 is substantially greater than the thickness of the material forming the tape 10 to produce a substantial bead indicated generally at 32 in the folded edge of the tape 10. Cord means, such as a pair of textile cords 34 and 36 or the like, extends longitudinally on the outside of the tape 10 alongside and in engagement with the bead 32. The textile cords 34 and 36 are illustrated as being secured to the outside of the tape 10 by stitches 38. Other means of securing the textile cords 34 and 36 to the tape may be used such as adhesive, mechanical, or other bonding means; also an overedge stitch may be used as an alternative to the illustrated straight stitch.Where a pair of cords 34 and 36 are employed on opposite sides of the folded tape 10 as shown in Fig. 3, the thickness of the combined cords 34 and 36 with the tape therebetween is selected to be generally about equal to the thickness of the bead 32 and the coupling element 14.

The cords 34 and 36 provide a bearing surface for flanges 42 and 44 of the slider 18 and protect the sheet material forming the bead 32 in the tape 10 from wear due to engagement by the slider flanges 42 and 44.

Additionally the textile cords 34 and 36 provide a smoother and more compliant surface for the slider flanges rendering operation of the slider 18 easier. Also the cords 34 and 36 distribute slider stress over a substantial area of the bead 32 to reduce point stress, such as occurs where the filament engages the tape. Thus, the cords 34 and 36 render possible the manufacture and construction of a slide fastener employing folded synthetic polymer tapes with greatly increased wearability and durability as well as the ability to withstand relatively large crosswise stress from slider operations.

The cords 34 and 36 in conjunction with the wide strap portion 30, the oblique ang]e of the slits 28 over the folded edge of the tape 10, and the aligned longitudinal dimensions of the cross sections of the leg portions with the slit, result in generally the full strength of the strip 27 securing the interconnecting portions 26; the tendency of the strap portions 30 to fail near the ends of the slits 28 or where the leg portions 22 and 24 exit therefrom is reduced by the distribution of forces by the cords 34 and 36.

In the modification shown in Figs. 5 and 7, a cord 50 is disposed within the folded edge of the tape 10 engaging the outside curvatures of the interconnecting portions 26. Preferably the cord 50 is formed from a resilient material such as a textile thus forming suitable seats 52 for the heel portions 26. The cord 50 adds to the stability of the coupling element 14 and allows the strap portions 30 to more securely hold the heel portions 26 to the tape 10 due to the resilience of the cord 50.

As illustrated in Fig. 8, another modification of the stringer is the use of a single external cord 36 on only one side of the tape with the planar portion of the tape 10 being offset with respect to the bead 32 and the coupling element 14. In Fig. 9, still another modification of the stringer includes the internal cord 50 together with the single external cord 36 and the offset planar portion of the tape 10. The asymmetrical version of the stringer would be used with a slider having only flanges on one wing thereof to engage the external cords, the opposite side of the tape presenting a smooth surface.

Since many variations, modifications, and changes in detail may be made to the described embodiment it is intended that all matter in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

WHAT WE CLAIM IS: 1 A stringer of the type specified, wherein the coupling element has a thickness to form a bead along the folded edge of the tape, and further has a bearing for engagement by a slider for the fastener formed by securing a cord or cords to the external surface of the folded tape to extend longitudinally alongside the bead.

2. A stringer according to claim 1, wherein there are a pair of cords secured to opposite external surfaces of the folded tape.

3. A stringer according to claim 1, wherein there is a single cord secured against one surface of the folded tape and the tape beyond the bead is offset in a plane to one side of the coupling element.

4. A stringer according to any of claims 1 to 3, wherein the tape is of synthetic polymer resin.

5. A stringer according to any of claims 1 to 4, wherein the folded portions of the tape are secured together by a threadless bond.

6. A stringer according to any of claims 1 to 5, wherein the head of each coupling section is joined to the interconnecting portions by legs which extend from opposite sides of the head, and the slits are at an oblique angle to the folded edge, the legs of each coupling section passing through the respective slit on opposite sides of the folded edge.

7. A stringer according to claim 6, wherein the continuous filament coupling element has an oblong cross-section, and the legs of each coupling section are such that their longer cross-sectional dimensions are aligned with each other and with the oblique slit through which the legs pass.

8. A stringer according to any of claims 1 to 7, including a further cord extending longitudinally of the stringer and between the folded portions of the tape in contact with the interconnecting portions remote from the folded edge.

9. A stringer according to claim 8, wherein the further cord is a resilient cord which is deformed by the interconnecting portions.

10. A stringer for a slide fastener substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4, or these Figs. as modified by Figs. 5 and 7 or by Fig. 8 or by Fig. 9 of the drawings.

11. A slide fastener having stringers as claimed in any of claims 1 to 10.

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Claims

**WARNING** start of CLMS field may overlap end of DESC **.

leg portions 22 and 24 exit therefrom is reduced by the distribution of forces by the cords 34 and 36.

In the modification shown in Figs. 5 and 7, a cord 50 is disposed within the folded edge of the tape 10 engaging the outside curvatures of the interconnecting portions 26. Preferably the cord 50 is formed from a resilient material such as a textile thus forming suitable seats 52 for the heel portions 26. The cord 50 adds to the stability of the coupling element 14 and allows the strap portions 30 to more securely hold the heel portions 26 to the tape 10 due to the resilience of the cord 50.

As illustrated in Fig. 8, another modification of the stringer is the use of a single external cord 36 on only one side of the tape with the planar portion of the tape 10 being offset with respect to the bead 32 and the coupling element 14. In Fig. 9, still another modification of the stringer includes the internal cord 50 together with the single external cord 36 and the offset planar portion of the tape 10. The asymmetrical version of the stringer would be used with a slider having only flanges on one wing thereof to engage the external cords, the opposite side of the tape presenting a smooth surface.

Since many variations, modifications, and changes in detail may be made to the described embodiment it is intended that all matter in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

WHAT WE CLAIM IS: 1 A stringer of the type specified, wherein the coupling element has a thickness to form a bead along the folded edge of the tape, and further has a bearing for engagement by a slider for the fastener formed by securing a cord or cords to the external surface of the folded tape to extend longitudinally alongside the bead.
2. A stringer according to claim 1, wherein there are a pair of cords secured to opposite external surfaces of the folded tape.
3. A stringer according to claim 1, wherein there is a single cord secured against one surface of the folded tape and the tape beyond the bead is offset in a plane to one side of the coupling element.
4. A stringer according to any of claims 1 to 3, wherein the tape is of synthetic polymer resin.
5. A stringer according to any of claims 1 to 4, wherein the folded portions of the tape are secured together by a threadless bond.
6. A stringer according to any of claims 1 to 5, wherein the head of each coupling section is joined to the interconnecting portions by legs which extend from opposite sides of the head, and the slits are at an oblique angle to the folded edge, the legs of each coupling section passing through the respective slit on opposite sides of the folded edge.
7. A stringer according to claim 6, wherein the continuous filament coupling element has an oblong cross-section, and the legs of each coupling section are such that their longer cross-sectional dimensions are aligned with each other and with the oblique slit through which the legs pass.
8. A stringer according to any of claims 1 to 7, including a further cord extending longitudinally of the stringer and between the folded portions of the tape in contact with the interconnecting portions remote from the folded edge.
9. A stringer according to claim 8, wherein the further cord is a resilient cord which is deformed by the interconnecting portions.
10. A stringer for a slide fastener substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 4, or these Figs. as modified by Figs. 5 and 7 or by Fig. 8 or by Fig. 9 of the drawings.
11. A slide fastener having stringers as claimed in any of claims 1 to 10.