US3490110A - Slide-fastener stringers for bed linen and the like - Google Patents

Description

A. FRbHLlCH Jan. 20, 1970 NEW AND THE L125:

SLIDE-FASTENER STRINGEFLS FOR BED LI 3 Sheets-Sheet 1 Filed Jan. 22, 1968 Alfons Frihlich m VEN TOR A. FRC'JHLICH Jan. 20, 1970 5 Sheets-Sheet 2 Filed Jan. 22, 1968 'Asfans Frdhiich [1\ VEN TOR Jan. 20, 1970 A. FRCHLICH 3,490,110

SLIDE-FASTENER STRINGERS FOR BED LINEN AND THE LIKE Filed Jan. 22, 1968 3 Sheets-Sheet 3 Alfons Fr'o'hlich INVENTOR.

Attorney United States Patent 3,490,110 SLlDE-FASTENER STRINGERS FOR BED LINEN AND THE LIKE Alfons Frtihlich, Essen, Germany, assignor to Opti- Holding A.G., Glarus, Switzerland, a corporation of Switzerland Filed Jan. 22, 1968, Ser. No. 699,583 Claims priority, application Germany, Jan. 21, 1967, 0 12,245 Int. Cl. A44b 19/04, 19/22 US. Cl. 24-2051 10 Claims ABSTRACT OF THE DISCLOSURE My present invention relates to a slide-fastener stringer for bed linen and other fabric articles of a shrinkable material.

The use of slide fasteners in garments and other fabric articles and in upholstery, pillow covers and the like has had widespread acceptance although similar use of closures of this nature has hardly entered the field of bed linen. It has indeed been proposed to make use of modern types of slide fasteners, i.e. closures using continuous coupling elements of meandering or helical configuration on respective support tapes, but considerable difficulties were presented when conventional slide fastener stringers where applied to bed linen and the like. Bed linen is generally characterized by a high cotton content and is for the most part woven so as to withstand rigorous cleaning treatments. During fabrication processes, the fabric is treated at elevated temperatures in such manner as to give rise to a 10% or more shrinkage in the length or Width of the fabric. Where attempts were made to mount conventional slide fastener stringers on fabrics for use in contoured sheets, mattress covers, pillow slips and blanket covers, for example, it was found that the thermoplastic slide fastener, once stitched in place, produced considerable wrinkling and stressing of the fabric as a result of such shrinkage.

Moreover, conventional methods of making the slidefastener assemblies have required that the coupling heads formed on the meandered ribs or the successive turns of a helicoidal filament be laid in practically contacting relationship so that no clearance or play is found between the interengaged head. Only in this manner, has it been possible to insure a sufficient tight junction between coupling elements and to provide the necessary transverse strength resisting separation of the coupling elements.

It is, therefore, the principal object of the present invention to provide a slide-fastener stringer which is especially suitable for use in bed linen and other fabric articles which may be subjected to high shrinkage phenomena.

Another object of this invention is to provide improved slide-fastener stringers for fabric articles with relatively high transversed or shear strength resisting separation of the interengaged coupling elements.

Still another object is to provide an improved method of making a slide-fastener assembly.

I have now found that it is possible to fabricate articles of a shrinkable fabric with slide-fastener stringers whose chains or rows of coupling heads are formed from a continuous thermoplastic monofilament with an interhead spacing exceeding the normal spacing necessary for proper interfitting of the coupling heads and dimensioned such that, upon shrinkage of the fabric band carrying the coupling elements, the gap between heads is reduced to the desired tolerance for tight fit. It has been found, for example, that the slide-fastener stringers for bed linen and the like can comprise a pair of support or carrying bands or tapes, advantageously composed of a fabric shrinkable to the same extent as that of the bed linen in the direction in which these bands extend, the tapes being provided along their approaching longitudinal edges with continuous coupling elements whose heads are spaced upon by an amount exceeding the normal head width but such that, with shrinkage up to about 10% in the overall length of the band (preferably about 5% shrinkage), the gap between heads is shortened such that the heads of the other coupling element are engaged in a tight-fitting manner.

In accordance with a preferred embodiment of this invention, the coupling elements are-coupled of syntheticresin rnonofilaments (e.g. a nylon polyamide) with a filament diameter of 0.2 to about 0.6 mm., the shrinkage step reading to a decrease in a gap width of about 0.1 mm. so that the overall shrinkage of the coupling chain 0.1 N mm. where N is the number of coupling heads and the shrinkage is 0.1 mm. per coupling head. I have chosen the term foreshortening play to indicate the amount by which the interhead width exceeds the width of the head and, therefore, the amount by which each gap must be reduced to bring the heads defining it into tight-fitting engagement with the head of the other coupling element received in this gap.

The present invention is based upon the fact that coupling elements of the continuous type, i.e. formed with a continuous chain of coupling heads molded by heat and pressure in the respective turns of a couplingelement coil of thermoplastic synthetic resin, is able to be subjected to elastic deformation in the longitudinal direction because the successive turns constitute in effect a coil spring. Thus the shrinkage of the fabric upon which the coils are mounted can be used directly or indirectly to condense the coils through the clearance or play originally provided between the heads, thereby bringing each pair of coupling heads into tight-fitting or hugging engagement with the coupling head of the opposing element which previously was only loosely received in the interhead space. When reference is made hereinafter to an indirect shrinkage effect upon the coupling coils, it will be understood that reference is intended to the use of a support band or tape between the coupling elements which, in a direct-action system, are mounted upon the fabric of the article without an intermediate band. When the band is used, however, I prefer to constitute it of a shrinkable material adapted to sustain at least the same degree of shrinkage as the fabric article to which it is attached. The shrinkage of the band and fabric article, during the usual fabric-handling treatments which give rise to such shrinkage in the longitudinal direction of the coil, mechanically condenses the coil and brings each coil into tight-fitting engagement with the heads of the opposing coil. When the fabric-handling treatment involves heat of a sufficient degree to set the thermoplastic elements, the latter are locked in their tight-fitting engagement during (i.e. concurrently with) the fabric-handling shrinkage treatment. Thus, within the principles of the present invention, the slide-fastener elements may be fixed directly or indirectly along opposite edges of a shrinkage-fabric article (e.g. bed linen and the like composed of cotton or mixtures of cotton with other fibers) and need not interfit tightly; the resistance of the slide fastener to separation and its transverse strength are both minimum. When, however, after the fabric article is subjected to its first washing, (ie a fabric-handling treatment producing shrinkage), the coupling heads are drawn together by the fabric shrinkage and hug the heads of the opposing element therebetween.

According to a more specific feature of this invention, the coupling element is composed of a nylon-type monofilamentary polyamide having a circular cross-section and shaped into generally flat coils whose opposite longitudinal sides run parallel to the juxtaposed edges of the fabric band or the fabric article upon which the coupling elements are mounted. The coupling heads are formed by plastic deformation (i.e. underheat and pressure) of the turns of the flattened coil along the corresponding edge as has been described in application Ser. No. 651,757 and the host of prior patents dealing with helicoidal and meandering coupling chains; to provide the clearance or play between each pair of heads and the interfitting head of the opposing coupling element, I coil the circular cross-section monofilament thread with an interturn spacing or pitch in excess of the cross-sectional diameter of the thread or filament, the amount which the turn spacing exceeds the thread diameter being the play.

Alternatively, the longitudinal extent of the deformed portions or heads of the turns may be less than the corresponding gap between the heads whereby th diameter of the receiving portions of the coupling elements is larger than the length of the coupling surfaces of the coupling head to form thereby the play mentioned earlier. It is possible to provide a structure of this nature by a one-sided deformation of the coupling elements, ie by pressing the flattened turns in the plane of their major diameters transversely to the longitudinal direction with heat and pressure. The resulting coils may be of pearshaped cross-section. It has also been found advantageous to provide coupling elements which are composed of monofilamentary threads of thermoplastic synthetic resin with elliptical or sickle (crescent) shaped configuration, the turns being designed such that the individual coupling heads are inclined in the longitudinal direction and interengage, the heads being spaced such that shrinkage of the engageable slide fastener, upon the fabric-handling treatment discussed earlier, permits the interengaged heads to penetrate deeper into the interhead spaces.

It has been found that a variety of methods can be used effectively to secure the coupling elements to the fabric article or the support bands, typical methods including stitching, interweaving or interknitting of the coupling elements, or simply inserting the coupling heads or turns through a ladderlike array of openings previously formed in the fabric at the spacing of the heads prior to shrinkage. Generally, in the latter case, the turns will not be materially deformed. It has been observed that, with shrinkage of the fabric formed with th ladderlike array of openings, each turn is positively positioned by the web of material between the openings with the shanks of the flattened coils being practically contiguous with one another. When stitching techniques are employed, double-chain stitches may be used with a single continuous thread row or a plurality of parallel rows, the threads for the stitching operation having a shrinkage corresponding to that of the band and the article. The shrinkage of the stitching threads can be selected by proper choice of the yarn and fiber content, by adjustment of the thread tension or by selection of an appropriate spinning or twisting degree. It has also been found to be important to prevent the shrinkage force applied by the support band to the fabric articles at a value less than that developed by the fabric articles during their own shrinkage process. In other words, the shrinkage of the coils should be limited by the fabric of the article rather than the fabric of the hand. To this end, I may provide syntheticresin monofilamentary warp threads in the band which limit shrinkage thereof or which are shrinkable to establish, at the temperature of the first fabric treatment subsequent to attachment of the stringer, to a point such that further shrinkage of the band is limited at about the shrinkage of the fabric article. We have also found it to be highly advantageous to provide the band as a loose Weave or knit mesh which can condense upon shrinkage of the fabric article but which is not itself shrunk by the fabric treatment so that the band, like the coils, mechanically condenses upon shrinkage of the fabric. This latter arrangement has the significant advantage that a single stringer may be used on fabric articles with a wide range of shrinkage potential and on fabric articles of widely differing materials. The stringer should be provided with an ironable slider of the type described and claimed in my copending application Ser. No. 651,757 of July 7, 1967 or my application Ser. No. 698,226 (attorneys docket No. 5674) filed on or about Jan. 16, 1968 and entitled Slider with Cantilevered Guide Formations for Slide-Fastener Closures.

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 plan view, somewhat in diagrammatic form, of a slide-fastener stringer in a preliminary stage of manufacture and prior to shrinkage of the fabric article upon which it is provided;

FIG. 2 is a view similar to FIG. 1 showing the stringer after such shrinkage;

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1;

FIG. 4 is a view similar to FIG. 1 of another type of slide-fastener assembly showing the position of the interengaged coupling elements prior to shrinkage in solid lines and subsequent to shrinkage in dot-dash lines;

FIG. 5 is a cross-sectional view along the lines VV of FIG. 4; and

FIG. 6 is a plan view similar to FIG. 1 showing another embodiment of the instant invention.

In my copending applications Ser. No. 619,833 and Ser. No. 624,647, filed Mar. 1, 1967, and Ser. No. 653,402, filed July 14, 1967, l have pointed out the advantages of ladderlike arrays of openings for receiving the individual heads of a continuous coupling element for a slide-fastener stringer of the general character described above. In those applications and in the present case, similar principles are involved, namely, the coupling elements are in part anchored in place by shrinkage of a fabric material. In this connection, reference is directed to FIG. 6 which provides the ladderlike array of openings analogous to those illustrated and described in connection with application Ser. No. 619,833.

In FIG. 1 of the present case, I show a fabric support comprising a pair of bands la and 1b which represent a shrinkage fabric to which a pair of continuous coupling elements 2 and 3 are attached by parallel rows of doublechain stitches 9 whose paths are shown in broken lines in FIG. 1. The stitches are represented in structural terms in FIG. 3. The support 1a, 1b may represent the fabric article (e.g. bed linen, pillow slips, etc.) or support tapes which are to be secured to the fabric article subsequently as described above. As is apparent from FIG' 1, the interengageable coupling heads 6a and 6b are formed on respective turns of a pear-shaped cross-section monofilarnentary synthetic-resin thread by deforming these turns in the direction of arrow A and A under heat and pressure to create lateral protuberances 6a and 61;, respectively. The heads are each located along the outer longitudinal side of the shanks 7a and 7b forming the turns, the shanks being attached to the bands 1a and 112 by the row of double-chain stitches 9 (FIG. 3).

The spacing D between the turns of the coupling elements 2 and 3 exceeds the diameter d of the monofilamentary material by amounts represented at 5 which correspond to the play between each pair of heads of one coupling element and the head of the other coupling element received between them. The gaps 4 are designed to amount to up to of the overall length of the coupling element and preferably about 5% thereof with about 0.1 mm. per interhead space. Consequently, the interengaged coupling elements of FIG. 1, prior to shrink age, fit with considerable looseness. It is desirable, moreover, that the protuberances 6a and 6b project outwardly from the respective heads in the longitudinal direction by approximately 0.1 mm. The cross-section of the coupling-element threads is substantially similar while each turn is deformed into a pear-shaped cross-section (FIG. 3) such that the diameter of the socket 8 of the coupling members at 4 is greater than the length of the coupling protuberances 6a and 6b. The one-side pressures upon the coupling turns in the direction of arrows A and A causes an inward bowing of the shanks 7a and 7b of each turn toward one another, thereby permitting the diameter of the receptacle 8 to be larger than that possible when the shanks will bend away from one another. When the fabric support 10, 1b is subjected to its first washing after the attachment of the coupling elements to the fabric article, the fabric shrinks substantially (FIG. 2), (preferably about 5%) to mechanically condense the couplingelement coils 2 and 3 and thereby provide the tight fit shown in FIG. 2.

In F165. 4 and 5, the coupling elements 12 and 13 are constituted of a monofilamentary resin with generally elliptical or sickle-shaped cross section (see especially FIG. 5). Here again, the coupling elements may be attached to a shrinkable fabric support 11a or 11b or to a loosely woven tape or band which is secured to the shrinkable bed linen. The individual turns or coupling heads 14 here interfit and are inclined toward the longitudinal direction B. The spacing between the coupling heads 14 is so chosen that, with shrinkage of the bands 11a and 11b, the coupling heads penetrate deeper into the gaps between the coupling heads of the opposing elements by the foreshortening play represented at 15. In FIG. 4, the preshrinkage position of the coupling elements 12 and 13 is represented in solid lines while the postshrinkage position is shown by dotdash lines.

FIG. 6 shows another embodiment of this invention wherein the shrinkage of the band 21a and 21b which are to be stitched to the fabric article, is limited by thermally shrinkable warp threads diagrammatically illustrated at but constituting the entire warp array. The bands 21a and 21b are formed with a ladderlike array of openings 21b through which the coupling heads 24 of the coils 22 and 23 (see FIGS. 1 and 2) extend. The coupling elements are retained in place upon shrinkage of the fabric bands as described in my copending applications Ser. Nos. 619,833 and 624,647. Upon shrinkage, the dot-dash position of the coupling elements is assumed and the foreshortening play is represented at 25. In all of the embodiments, one or more rows of double-chain stitches 9 may be provided to retain the coupling elements upon the band or fabric article as illustrated in FIGS. 15. The thread tension of these stitches is selected such that they permit shrinkage in step with the fabric. The bands 1a, 1b, 11a, 11b and 21a, 21b may be loosely woven or knitted condensable fabric tabs which allow shrinkage of the fabric and the coupling chains of the bed linen during the initial washing process. When the band is shrinkable (FIG. 6) synthetic-resin monofilament threads 10 are provided to limit the total shrinkage of the band approximately to the shrinkage of the fabric.

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 invention.

I claim:

1. A slide-fastener assembly adapted to be mounted upon a shrinkable fabric article and having a shrinkable fabric support and a pair of interchangeable continuous coupling elements with a multiplicity of turns each forming a coupling head receivable between coupling heads of the other coup-ling element and compose of a synthetic resin, the coupling heads of each element being spaced apart to receive the coupling heads of the other element with a play reducible by shrinkage of said support up to 10% of the length of the coupling elements.

2. The assembly defined in claim 1 wherein the support is a respective fabric tape carrying each of said coupling elements and attachable to said fabric article, said play between each pair of coupling heads being about 0.1 mm.

3. The assembly defined in claim 2 wherein said coupling elements are coils of a thermoplastic monofilament of circular cross-section and said heads are formations shaped in the successive turns, the spacing between the turns being greater than the diameter of the monofilament to form said play.

4. The assembly defined in claim 3 wherein the coils forming said coupling elements are generally flattened, said heads being formed by inward deformation of said turns along one longitudinal side of each flattened coil.

5. The assembly defined in claim 3 wherein said bands are formed with ladder arrays of openings at the spacing of said heads and receiving the successive turns of said coupling elements.

6. The assembly defined in claim 3, further comprising respective arrays of stitches securing each of said coupling elements to the respective band, said stitches being formed of a shrinkable thread.

7. The assembly defined in claim 3 wherein said bands are formed with warp threads extending parallel to the respective coupling chains and composed of a thermally shrinkable synthetic resin, the extent of the shrinkage threads defining the degree of shrinkage of said coupling elements in the longitudinal direction.

8. The assembly defined in claim 3 wherein said bands are composed of a fabric with a shrinkage force less than that of said article.

9. A method of making a slide-fastener assembly for a fabric article up to 10% in at least one direction, comprising the steps of forming a pair of coupling-element coils of thermoplastic monofilamentary synthetic resin with respective coupling heads on each turn of the coils receivable between the coupling heads of the other coil and with an interhead spacing forming with the heads of the opposing coil clearances of about 0.1 mm.; mounting said coils upon respective support bands of a fabric shrinkable in the longitudinal direction by an amount of about 10% over the length of the respective coil; securing the respective bands to the fabric article with the bands and said elements extending in said direction; and subjecting said article to a fabric treatment with said bands secured thereto to shrink the article, said bands and said coils, thereby condensing the heads of each coil by said clearance.

10. The method defined in claim 9 wherein said bands and said coils are shrinkable by about 5% in the longitudinal direction, said article being bed linen, said fabric treatment being the initial washing of the bed linen subsequent to the securing of said bands thereto.

References Cited UNITED STATES PATENTS 1,724,311 8/ 1929 Prentice. 1,848,877 3/1932 Gay 26--1 X 3,354,853 11/1967 Haussmann.

BERNARD A. GELAK, Primary Examiner US. or. X.R.

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