US3423803A - Multi-strand slide fastener - Google Patents

Description

Jan. 28, 1969 A. FRC'JHLICH 3,423,803

' MULTI-STRAND SLIDE FASTENER 1 l Filed July 14, 1967 Sheet of 2 -INVENTOR.

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Filed July 14, 1967 Sheet -2 Jan. 2 1969 v A. FRHL|H 3,423 803 MULTI-STRAND SLIDE FASTENER INVENTOR.

FIG. 8 I

United States Patent 0 11,874 US. Cl. 24--205.13 5 Claims Int. Cl. A44b 19/00 ABSTRACT OF THE DISCLOSURE A coupling element adapted to be affixed to a support tape to form one half of a slide-fastener stringer, the coupling element consisting of a coil of a number of intertwined synthetic-resin thermoplastic monofilamentary strands, the turns of which have mutually parallel and coplanar shanks terminating at a respective flattened head (along one side of the coil) with protuberances extending in the direction of the coil axis and transversely to the plane of the turn. The heads are spaced apart while the bight connecting each of the shanks with the shank of the next turn of the same strand extend at an angle to the axis of the coil (i.e. at the pitch angle) and in contiguous fiank-to-flank contact with the corresponding bight of the adjacent turns of the other strands.

My present invention relates to slide-fastener assemblies and, more particularly, to coupling elements for slide fasteners of the helicoidal-coil type.

While earlier slide-fastener systems have generally employed a multiplicity of spaced-apart coupling elements individually affixed to a support tape, it has been found that a high degree of coupling effectiveness can be obtained in slide fasteners when the coupling elements along the confronting edges of the stringer tape are constituted as continuous coils of thermoplastic filament which interengage upon movement of the slider in one direction and disengage upon movement of the slider in an opposite direction along the coupling element. Such systems are described and claimed in the commonly assigned copending applications Ser. No. 472,953, (US. Patent No. 3,355,256) Ser. No. 473,002 (US. Patent No. 3,353,233) and Ser. No. 473,003 (US. Patent No. 3,340,594) filed July 19, 1965; Ser. No. 591,753 filed Nov. 3, 1966; Ser. No. 619,768, Ser. No. 619,833 and Ser No. 624,647 filed Mar. 1, 1967; and Ser. No. 620,972 filed Mar. 6, 1967.

In general, such coupling elements can be described as helicodial coils deformed along one longitudinal side into a plurality of spaced-apart heads which are interfittable with the correspondingly spaced heads of a complementary coupling element. It has already been proposed to form such coupling elements by coiling a monofilamentary thermoplastic strand upon a mandrel or core wire and to deform the turns by rollers, plungers and the like so as to impart a flattening at the heads and form projections in the direction of slider movement. These p-rojections engage between the turn of the complementary coupling element when the slide fastener is to be closed. In general, difliculties are encountered with respect to the maintenance of the desired interturn spacing and with the rate of production of the coupling element since small pitches are required and close spacing tolerances are necessary when fine slide fasteners are to be made.

It is, therefore, the principal object of the present invention to provide improved coupling elements of the character described whereby the rate of production can be increased and fine slide-fastener assemblies (i e. with thin filaments) can be made without encountering the difficulties mentioned earlier. A further object of this in- 3,423,803 Patented Jan. 28, 1969 vention is to provide an improved coupling element for the purposes described.

I have now found that it is possible to increase the rate of production of coupling elements for slide fasteners without increasing the tolerances thereof and to produce relatively fine coupling elements with close fixed spacing, by helicoidally winding a plurality (e.g. two or three) of synthetic-resin monofilamentary thermoplastic strands about a mandrel or other support in close-contacting relatacting relationship so that, at least along one longitudinal side of the coil, the adjacent turns of the several strands are in contacting relationship. Thereafter, or concurrently, the coil may be deformed along its opposite longitudinal side so as to impart the desired head configuration and separation to the adjacent turns while the bight portions between these turns remain in contacting relationship along their flanks and have a scale-like overlapping appearance. According to a more specific feature of this in vention, the mutually contacting bight portions of the plural strands maintain the spacing of the respective heads while the pitch of each of the strands may be two or more times the pitch of earlier helicoidal coupling elements With corresponding head spacing.

Advantageously, the contacting bight portions are deformed so as to be interfitting, thereby providing relative shifting of the strands making up the coil. I have found, moreover, that the formation of the head can be improved by shaping each turn so that each head is coplanar with a pair of mutually parallel shanks joining the head with the bight portions of the adjacent turns of the same strand. The mutual and direct contact of the bight portions rigidly maintains the shanks and the heads in the desired spaced relationship and a relatively rigid coupling element is constituted without danger of distortion and dislocation when the bight portions have a scale-like and overlapping configuration.

The planes of the shanks and the respective heads are perpendicular to the plane of the support tape and to the direction of movement of the slider while the bight portions are oblique to these planes. The separation between the heads is thus readily maintainable at its original tolerance. Furthermore, a core wire or member can be inlaid within the coil which, moreover, can be deformed so as to be of elliptical configuration as described and illustrated in some of the aforementioned copending applications. Attachment of the coupling elements to the respective support tape can be accomplished without difficulty by any conventional means as described in these copending applications. Thus, the coupling elements can be affixed by thermal bonding, adhesives, chain stitching or the like to a foil or fabric band or mounted therein by insertion of the heads through spaced-apart openings in a sleeve-like formation of the fabric band. Relatively fine strands may be wound at high rate to produce the coupling elements according to this invention.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a side-elevational view of a pair of coupling elments simultaneously formed by the coiling of a pair of monofilamentary strands according to this invention;

FIG. 2 is a cross-sectional view taken generally along the line II-II of FIG. 1;

FIG. 3 is an end view of the turns of the coupling element taken generally in the direction of arrow III of FIG. 1;

FIG. 4 is a View similar to that of FIG. 1 of a step of the process of forming coupling elements by the concurrent coiling of three strands;

FIG. 5 is a cross-sectional view taken generally along the line VV of FIG. 4;

FIG. 6 is a view taken in the direction of arrow VI of FIG. 4;

FIG. 7 is a view similar to FIG. 3 representing a modification of the coiling system of FIGS. 1 through 3;

FIG. 8 is a diagrammatic elevational view, partly in section, of an apparatus for carrying out the present invention; and

FIG. 9 is an enlarged cross-sectional view representing a detail of the region IX of FIG. 8.

In FIGS. 1 through 3, I show a stage of the formation of the coiling elements of a slide-fastener assembly which Coupling elements are adapted to be afiixed to the respective support tapes or bands to form a coupling half. As described in my copending applications mentioned earlier, as well as the cases referred to therein, these coupling elements maybe inset in the fabric tapes, woven into the latter, stitched, thermally bonded or otherwise fastened to the tapes or cemented thereto in a substantially continuous process. I have found it to be particularly desirable to insert the coupling elements into sleeve-like formations along the support tapes and to shrink this fabric around the shanks and bight portions of the coupling elements thereby exposing the heads thereof. As pointed out in the aforementioned copending applications, the coupling elements, upon their respective support tapes, form slide-fastener halves which may be interconnected and pass continuously through a finishing station at which end-stop members are formed from the thermoplastic coupling elements and a foil applied thereto by heat and pressure, while severing of the individual lengths of slide fasteners occurs concurrently or thereafter in the region of molding of the end-stop members. The slide-fastener band may be provided with a slot in the region of the foil strap and the respective slider inserted onto the individual length at such slot.

Each of the coupling elements is a continuous chain of a molecularly oriented monofilamentary synthetic resin, e.g. nylon-type polyamide, coiled in a generally helicoidal sense and provided with spaced-apart coupling heads 3. According to an improved feature of this invention, the coupling element 2 of each slide-fastener half comprises a plurality of monofilamentary strands 4a and 4]) (also 4c in the system of FIG. 6) intertwined and wound together (see FIGS. 2 and 3). As can be seen from FIG. 3, the heads 3 of the strands 4a and 4b are formed identically and alternated along the coupling element with a spacing S equal generally to the width W of the shanks. The heads 3 are deformed so as to have flattened portions 3:: and lateral projections 31) and 3c respectively engageable beneath the corresponding heads of the coupling element of the other slide-fastened half.

The heads 3 are formed as loops connecting the shanks 6a and 6b of each turn, the shanks being generally parallcl to one another and being interconnected along the strands by arcuate bight portion 6 remote from the heads. These bight portions 6 run at the pitch angle of the helix along the respective helix lines of the coil whereas the shanks 6a and 6b and the heads 3 extend generally along diameters of the helix. The coils are so deformed that the heads 3 are spaced apart as indicated earlier while the bight portions 6 of the two strands 4a and 4b are in mutual flank-contacting relationship, i.e. the bight portions lie one against the other in a generally contiguous arrangement and are mutually parallel so that the spacing between the bight portions of successive turns of one strand is equal only to the diameter d of the other strand whose bight portion forms a spacer between the successive turns of the first-mentioned strand. In the system of FIGS. 1 through 3, the couplingelement chain 1 is constituted as a two-strand helix whereby both helical strands along the support-tape side (20) lie against one another in a scalelike and overlapping relationship (see especially FIG. 3).

In the system of FIGS. 3 through 4, three strands 34a, 34b and 34c are coiled together with free-standing heads 33 of the configuration described in connection with FIGS. l3. Here, too, the heads 33 and the shanks 35 of each turn of each strand are coplanar, i.e. lie in a plane P perpendicular to the axis A of the helix with the projections 33]) and 33c extending transversely to this plane. The bight portions 36a, 36b and 360 of the turns of the individual strands abut one another in a contiguous manner throughout the length of the coupling element 32 and overlap one another in a scale-like arrangement. The bight portions 36a through 360 are mutually parallel and extend along the helicoidal lines determined by the winding pitch and form spacers between alternate strands. It will be evident, therefore, that strand 34b forms a spacer between the bight portions 36:: and 360 whereas strand 340 forms the spacer between bight portions 36b and 36a, and strand 34a forms the spacer between bight portions 360 and 36b.

The shanks 35, moreover, are substantially parallel to the plane of the slide fastener represented as P in FIG. 5 and are orthogonal to the direction of slider movement for opening and closing the slide fastener (arrow B). The projections 33b and 330 of the heads 33 extend in the slider-opening and slider-closing direction represented by this arrow.

As set forth in some of the aforementioned copending applications, a core 7 of elastomeric material, fabric or the like can extend through the helicoidal coils to improve the sealing ability of the slide fastener and the degree at which it is affixed to the respective tape. Furthermore, the fianks of each turn, or some of them, can be deformed to accommodate a chain stitch for affixing the coupling element to the support tape as indicated in some of the copending applications mentioned earlier and the .prior art of this class.

In FIG. 7, I show a modified system wherein the bight portions 46 of the individual turns 44a and 44b are deformed after coiling so that the adjacent turns of the two coils are at least partly received in one another so that a shifting of one of the strands with respect to the other is prevented. The helix is thereby retained with its original open-work dimension (cf. FIGS. 1 and 4). It will be apparent that this arrangement permits the coupling element to be manufactured with well-defined and relatively close spacing and yet with relative large pitch (e.g. as represented at 9), thereby permitting a high manufacturing speed. The mutually interfitting construction of the contaeting sides of the bight productions (FIG. 7) insures retention of the relative positions of the two strands at least until they are affixed jointly to the slide-fastener half.

In FIGS. 8 and 9, I show an arrangement for producing slide-fastener coupling elements of the character described. In this arrangement, a central shaft 12 is provided with a mandrel 13 and rotatably supports a bobbin carrier generally represented at 10. This bobbin carrier is journaled by bearings 10a and 1% upon the shaft 12 and is bolted to a gear 10c which is driven by a pinion 10d of a motor not shown. The bobbins 10c and 10 carrying thermoplastic synthetic resin monofilament, payoff the strands 11 through respective hoods 10g and 10h enclosing the bobbins. The strands 11 pass through the guide apertures 101' and 101' in a plate 10k at the lower end of the bobbin carrier 10 at which the strands are wound in close contact with one another about the mandrel 13. This close winding is represented in enlarged view in FIG. 9. The helicoidal coil of monofilamentary strands is drawn off the end 13' of mandrel 13 into the teeth of a forming wheel 14 which cooperates with a roller 15 to form the shanks 5 and 35 into their spaced-apart relationship under heat and pressure. Alternatively, a coiling wire may be introduced at the end of the mandrel and passed through the forming station 14, 15 with the coils and, thereafter be subsequently removed by chemical solubilization or thermal means (eg. high-temperature destruction). From the forming station 14, 15, the coupling element passes under a further roll 16 at which the heads 3, 33 are flattened to form the protuberances 3b, 3c and 33b, 33c prior to coiling the coupling elements upon a takeup roll 17. The toothed wheel 14 can be heated to a temperature suflicient to thermally fix the coupling elements 2, 32 etc. in their deformed condition. The coupling elements, then having the configuration represented in FIGS. 1-3, 4-6 or 7, can be mounted upon the respective support tape as described in the aforementioned copending applications.

The invention described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the appended claims.

I claim:

1. A coupling element for attachment to a support band to form a slide-fastener half, comprising a generally helicoidal coil of a plurality of intertwined monofilamentary thermoplastic synthetic-resin strands with the turns thereof having bight portions along one longitudinal side of the coil in mutually contacting relationship, and spacedapart coupling heads along the other longitudinal side of the coil for mating interengagement with corresponding coupling heads of a similar coupling element.

2. The coupling element defined in claim 1 wherein 6 said bight portions of said turns overlap in scale-like configuration.

3. The coupling element defined in claim 2 wherein the mutually contacting bight portions of the adjacent turns are at least partly interfitted to prevent relative shifting of said strands.

4. The coupling element defined in claim 2 wherein each of said turns has a head coplanar with a pair of mutually parallel shanks and each head has protuberances projecting transversely to the plane of the head and its shank.

5. The coupling element defined in claim 4, further comprising a core element extending through said coil along said one side.

References Cited UNITED STATES PATENTS 2,643,432 6/1953 English. 3,067,476 12/ 1962 Cromberg. 3,189,964 6/1965 Galonska.

BERNARD A. GELAK, Primary Examiner.

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