WAISTBAND INTERLINING

Abstract: Waistband interlinings are made by weaving or knitting a fabric (10) having warp threads (1) and weft threads (2) of a thermoplastics material, and cutting the fabric along lines parallel to the warp threads, wherein the fabric is cut by pass­ ing it between a stationary pressing element (14) and the horn (13) of an ultrasonic generator, such that the weft threads are melted as they pass between the pressing element and the horn and are caused to fuse into adjacent weft threads to form a con­ tinuous edge (3) along the length of the cut fabric. The con­ tinuous edge may be reinforced by introducing an ancillary thermoplastics thread between the pressing element (14) and the horn (13). This ancillary thread also melts and fuses to the molten weft thread ends.

Description: WAISTBAND INTERLINING. The present invention is concerned with the production of waistband interlinings. It is conventional to produce waistband interlinings by cutting strips of appropriate length from relatively wide lengths, for example continuous lengths, of woven or non-woven material. The interlinings are suitably cut from full width piece goods in the warp (or wale) direction by cold shearing or by the use of a hot knife. A disadvantage associated with this method of producing interlinings is that the cut edges of the fabric are rough. In the case of hot cutting a strip containing nylon or other thermoplastics material in the weft, the edges become even more rough and brittle. When such a strip is inserted wholly or partially round the garment waistband, the weft threads, normally monofilaments, tend to protrude through the waistband shell fabric and may cause irritation to the wearer. When the interlining is a strip woven on a narrow loom the return bights of the weft, i.e. the selvedge, tend to break, with the same undesirable protrusion of points which may penetrate the shell waistband fabric, abrade the same and cause irritation to the wearer. These disadvantages are overcome to a considerable extent by the process described in U.K.Patent Specification 1,213,957, according to which a continuous bead is applied to each cut edge of the interlining. One method for applying the continuous bead described in patent Specification 1,213,957 comprises continuously extruding a plastics composition onto the moving interlining strip. The continuous bead forms a finished edge which prevents the needle-like ends of the weft threads from penetrating or abrading the waistband shell fabric, which prevents displacement of the weft threads, and the material of which flows into the interstices of the interlining strip to unite the bead, warp and weft into an integrated whole. Whilst the method of the above-mentioned Specification works well, the production of an interlining strip in accordance with that method from a full-width fabric involves two distinct operations, namely cutting the strip from the full width piece goods and then extruding the edge bead onto it. It is an object of the present invention to provide a method of producing a waistband interlining having a "smooth edge" wherein the cutting of the interlining strip and the provision of smooth edges thereon are carried out in a single operation. According to the invention a method of producing a waistband interlining comprises weaving or knitting a fabric comprising warp threads and weft threads of which the weft threads are formed of a thermoplastics material, and cutting the fabric along lines parallel to the warp threads, wherein the fabric is cut by passing the fabric between a stationary pressing element and the horn of an ultrasonic generator whereby the weft threads are melted as they pass between said element and said horn and are caused to fuse into adjacent weft threads and/or adjacent warp threads and/or an ancillary thermoplastics thread introduced between said element and said horn to form a continuous edge along the length of the cut fabric. In its simplest form, the invention involves the melting of the weft threads and the fusing or "smearing" of their molten ends into each other to form a continuous edge. Additional strength can be obtained by causing the molten weft ends also to fuse into the adjacent o .4 warp, at least in plaves, or to the adjacent wale or course in the case of a knitted fabric. Fusing of the weft ends to the warp can be of benefit when it is desired to keep the number of weft threads low, either for reasons of cost or to reduce the stiffness of the fabric in the weft direction. In another embodiment of the invention the weft thread ends are fused into an ancillary thermoplastics thread introduced between the pressing element and the horn of the ultrasonic generator, this additional thread running parallel to the warp and being coincident with the parts of the weft being melted. The weft ends may be fused simply to this additional thread, or to the additional thread and each other, or to the additional thread, each other, and, at least at some points, to the warp or wale of the fabric. The use of the additional thermoplastics thread is of benefit when it is desired to keep the number of weft threads low, e.g. for the reasons mentioned above, or when for instance the particular desired running speed for the machine makes it difficult for the molten weft thread ends to flow into each other. The weft of the woven or knitted fabric is of a thermoplastics material, and is suitably a thermoplastics monofilament, e.g. a polyamide such as nylon; the warp, of any suitable material, may for example be of cotton or spun polyester, and is preferably of polyester viscose spun staple fibres The precise configuration of the continuous edge formed on the cut fabric is controlled by the speed of traverse of the material past the sonic unit, the shape of the pressing element, the amount of ultrasonic energy applied, and the degree of cooling, both to the horn and above and below the fabric beyond the pressing element. A machine for producing waistband interlinings using the method of the invention suitably comprises one or a number of stationary pressing elements positioned above one or more horns connected to ultrasonic generators. The machine also comprises means for feeding the fabric between the pressing elements and horns, means for drawing off cut fabric, and, where an ancillary thermoplastics thread is to be used, means for introducing such thread between the respective pressing elements and horns. The machine is operated such that the molten thermoplastics material of the weft between each pressing element and associated horn forms a bead which "bridges" one monofilament in the weft to the next, and/or to the ancillary thread, and optionally fuses also into the adjacent warp or wale. Various shapes or pressing elements may be used, depending upon the precise configuration which is required for the continuous edge. Preferably the diameter of the edge will be no greater than the thickness of the fabric, in order that no ridge will appear on the waistband shell fabric during garment wear. The pressing elements are suitably made from steel and subjected to a hardening process. The horn of the ultrasonic generator is suitably manufactured from titanium and carbide-tipped steel. The accompanying schematic drawings are given for the purpose of illustrating the invention. In the drawings Figure 1 is a cross-sectional elevation through an interlining strip of the invention, looking in the warp direction; Figure 2 shows one form of apparatus for the production of interlining strips from full width fabric; Figure 3 is a section on the line III-III of Figure 2; Figure 4 shows part of Figure 3 on an enlarged scale; Figure 5 shows one way of mounting the pressing elements; Figure 6 shows a number of pressing element shapes; and Figure 7 is a view similar to that of Figure 2, showing a modified apparatus for use with an ancillary thermoplastics thread. Referring to the drawings, an interlining fabric strip in accordance with the invention comprises warp yarns 1 interwoven or knitted with weft yarns 2. The ends of the weft yarns 2 merge into continuous edges 3. Referring to Figure 2, full width fabric 10 is fed from a feed-roller 11 around a guide-roller 12 and over the horn 13 of an ultrasonic generator operating at a frequency between 20 and 200, preferably 20 or 40,kHz. As the fabric passes over the top of the horn 13 it is pressed by a series of pressing/cutting elements 14 which cause the thermoplastics material of the weft threads which they engage to soften and, by virtue of the fact that the fabric is moving, to "smear" or merge into the following weft thread or threads. Cooling air is applied to the horn 13 and to the fabric 10 as it emerges from between the horn 13 and the pressing cutting elements 14, in order rapidly to cool the continuous cut and fused edges 3 of the interlining strips. The strips are thereafterpassedover a guide-roller 15 and wrapped around a take-up roll 16. The operation of the pressing/cutting element 14 is best seen in Figure 4. The element 14, which as shown is in the form of a disc, is preferably pivotally mounted, as shown in Figure 5, in order to exert a uniform pressure on the fabric 10. Fine control is possible when the spring is under the control of a pneumatic cylinder. The element 14 may have any desired shape, which is dependent on the desired configuration of the continuous edge 3. A selection of typical element shapes is shown in Figure 6. The cutting element shown in Figure 6(d) is in the form of a hollow ground "blade". Typically the pressing/cutting elements have "knife edges" of angle 750, 900,1200 or 1400. Figure 7 shows an apparatus, similar to that of Figure 2, but for use with an ancillary thermoplastics monofilament. The apparatus includes a pressing/cutting element 24 of octagonal shape, one pressing edge of which may be used at a time, and the guide roller 12' has one or more circumferential grooves to accommodate the ancillary monofilament(s) 25, the grooves being in alignment with the pressing elements 24. In operation, the ancillary monofilament 25 is fed between the fullwidth fabric 10 and the horn 13, and in alignment with the pressing element 24. Both the weft of the fabric 10 and the ancillary thread 25 are melted, thus "cutting" the fabric, and the ends of the weft threads fuse into each other and into thread 25 to form the continuous edge In an alternative construction the thread 25 may be guided between the element 24 and horn 13 by means of a guide tube situated between guide roller 12 and horn 13. There will naturally be one such guide tube for each ancillary thread 25. A typical operating frequency for the ultrasonic generator is 20 kHz. Typical operating speeds (i.e. feed and draw-off speeds) are lOm/minute for 400 denier woven fabric and 420 denier knitted fabric, 16m/minute for 250 denier knitted fabric. By virtue of the method of this invention it is possible to produce, in one operation, a waistband interlining strip having a flexible continuous thermoplastics edge which assists in the manufacture of garments and which provides protection against weft penetration of the waistband shell fabric throughout the life of the garment.

Claims: CLAIMS 1. A method of producing a waistband interlining comprising weaving or knitting a fabric comprising warp threads and weft threads of which the weft threads are formed of a thermoplastics material, and cutting the fabric along lines parallel to the warp threads, wherein the fabric is cut by passing the fabric between a stationary pressing element and the horn of an ultrasonic generator whereby the weft threads are melted as they pass between said element and said horn and are caused to fuse into adjacent weft threads to form a continuous edge along the length of the cut fabric. 2. A method as claimed in claim 1 wherein the weft of the fabric is a thermoplastics monofilament. 3. A method as claimed in claim 2 wherein the weft of the woven fabric is a nylon monofilament. 4. A method as claimed in any of claims 1 to 3 wherein the warp of the fabric is of cotton or spun polyester. 5. A method as claimed in any of claims 1 to 4 wherein the formed continuous edge has a diameter less than or equal to the thickness of the fabric. 6. A method as claimed in any of claims 1 to 5 wherein an ancillary thermoplastics thread is introduced between the pressing element and the horn, and is melted and fused to the molten weft threads forming the continuous edge. 7. A method of producing a waistband interlining comprising weaving or knitting a fabric comprising warp threads and weft threads of which the weft threads are formed of a thermoplastics material, and cutting the fabric along lines parallel to the warp threads, wherein the fabric is cut by passing the fabric between a stationary pressing element and the horn of an ultrasonic generator whereby the weft threads are melted as they pass between said element and said horn and are caused to fuse into an ancillary thermoplastics thread introduced between said element and said horn to form a continuous edge along the length of the cut fabric. 8. A method as claimed in claim 6 or 7 wherein the ancillary thread is a thermoplastics monofilament. 9. Apparatus for carrying out the method of claim 1, comprising one or more stationary pressing elements positioned above one or more horns connected to ultrasonic generators. 10. Apparatus for carrying out the method of claim 6 or 7 comprising one or more stationary pressing elements positioned above one or more horns connected to ultrasonic generators, and means for introducing one or more ancillary thermoplastics threads between said pressing element(s) and said horn(s). 11. Apparatus as claimed in claim 10 wherein a guide roller having one or more circumferential grooves is used to align the thermoplastic thread or threads with a respective pressing element.

Inventors: WOOD, STEPHEN ARTHUR
Applicants: H.G. GRAHAM & SON LIMITED
Application year: 1985
Main classification: A41F9
IPC codes: B29C65, A41F9, D06H7