AU777930B2 - Warp knitting - Google Patents

Description

P/00/01i1 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Applicant: WARP KNITTING DA'V'lD WIAMA~ KOST Gce t~~c -ke~ The following statement is a full description of this invention, including the best method of performing it known to me: 2 WARP KNITTING The present invention relates generally to warp knitting, and in particular to a process for warp knitting a fabric and a fabric so knitted. The fabric is applicable for use as a canopy in a covering structure, for example, in a net form as bird netting, hail netting or shade cloth. It will be convenient to hereinafter disclose the invention in relation to that exemplary application, although it is to be appreciated that the invention is not limited thereto.

In a typical application, a canopy fabric such as bird netting, hail netting or shade cloth is supported by a structure which covers a crop to be protected or an area to be shaded. These structures take a varieiy of forms, but have in common that it is desirable to stretch the fabric over the structure. However, it will be appreciated that a warp knitted fabric changes dimension when stretched out to its full extent. For example, a 12 needle to the inch warp knitted fabric typically has a length of 150m and width of 2m but when opened out has a width of 10m and a length of 100m.

In order to facilitate positioning of the fabric over a covering structure, heavy cords of steel wires have been hand threaded through specially formed eyelet holes spaced apart along the edges of such fabrics and then fixed to anchoring points during the installation process. However, hand threading such 20 cords is a time consuming and difficult process, and one which may result in damage to the fabric or below optimum performance if the cord is threaded roughly or incorrectly.

loll An object of the present invention is to provide a process for warp knitting a fabric incorporating at least one draw string and thereby obviate the *25 need for such a draw string to be subsequently threaded through the knitted fabric.

According to one aspect of the present invention there is provided a process for warp knitting a fabric incorporating at least one drawstring, including: feeding a plurality of warp threads to a warp knitting machine in accordance with a predetermined knit pattern; knitting the warp threads together in the predetermined knit pattern to form a fabric with an array of thread connections; feeding at least one drawstring to the warp knitting machine; and, W:*BtetSPECNRN64B077.doc progressively laying in the drawstring through the warp threads during knitting thereof in a manner which avoids capture at the thread connections so that the draw string extends through the fabric in a general direction of the warp threads and can be moved longitudinally relative to the fabric.

Preferably, the warp thread connections include loops and underlaps, and the drawstring is laid in through the warp threads to avoid capture between the loops and underlaps.

Preferably, the drawstring is laid in through the warp threads so as to pass between opposite sides of the knitted fabric. Moreover, preferably the drawstring is lai in through the warp threads so as to extend along at least one side of the knitted fabric.

In one preferred form, the drawstring is laid in so as to extend alternatively along opposite sides of the knitted fabric for a predetermined number of courses of thread connections. In another preferred form, the drawstring is laid in so as to extend substantially along one side of the knitted fabric but intermittently loop to the opposite side thereof. In one form, laying in the drawstring includes passing the drawstring between thread underlaps so that the drawstring passes between opposite sides of the knitted fabric.

Preferably, the warp threads are fed to at least a front bar of the warp 20 knitting machine for knitting, and the drawstring is fed to at least a back bar of the warp knitting machine for laying in. In one preferred form, knitting the warp threads includes repetitively moving the bar(s), to which the warp threads are fed, across needles in the warp knitting machine, and laying in the drawstring includes selectively moving the bar to which the drawstring is fed. With this O oooo arrangement, the drawstring bar is moved with the warp thread bar(s) the drawstring is placed on top of an underlap of a warp thread and so lies on one side of the knitted fabric. However, when the drawstring bar is held against movement while the warp thread bar(s) moves then the drawstring is placed under an underlap of a warp thread and so lies on an opposite side of the knitted fabric.

In one preferred form, the drawstring is laid in along an edge region of the fabric.

W: e~a SPECIRN4O0?7dc In one preferred form, the warp threads are knitted in a predetermined knit pattern which produces a netting fabric having holes therethrough and the drawstring is laid in so as to pass through some of the holes.

According to another aspect of the present invention, there is provided a warp knitted fabric manufactured using the above process.

According to a further aspect of the present invention, there is provided a warp knitting machine when used in the above process.

According to still another aspect of the present invention there is provided a warp knitting machine when used to manufacture the above warp knitted fabric.

It will be understood that the terms "fabric" and "fabrics" as used herein include any warp knitted fabric and, in particular includes netting.

It will be further understood that the term "thread" as used herein includes mono- and multi- filament threads, and also two or more threads which are twisted or drawn together for knitting with other threads.

It will also be understood that the term "drawstring" as used herein includes a line, cord, thread, filament or narrow strip of any material which can be laid into the fabric and suitable for the intended application of the fabric.

The following description refers to preferred embodiments of the knitting 20 process and knitted fabric of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the process and fabric are illustrated. It is to be understood that the invention is not limited to the embodiments as hereinafter described and as illustrated.

In the drawings, where the same reference numerals designate the same or similar components: Fig. 1 is a back side view of a piece of a warp knitted fabric manufactured using a process according to a preferred embodiment of the present invention; Fig. 2 is a back side view of a piece of another warp knitted fabric manufactured using a process according to a preferred embodiment of the present invention.

W kakeSPECIRN646077.doc Fig. 3 is a schematic layout of a plurality of warp threads of a piece of a knitted fabric and a drawstring showing how the drawstring is laid in the threads using a process according to a preferred embodiment of the present invention; Fig. 4 is a schematic layout of a plurality of warp threads of a piece of another knitted fabric and a drawstring showing how the drawstring is laid in the threads using a process according to a preferred embodiment of the present invention; and Fig. 5 is a schematic layout of a plurality of warp threads of a piece o yet another knitted fabric and a drawstring showing how the drawstring is laid in the threads using a process according to a preferred embodirneni of the present invention.

Referring initially to Fig. 1 of the drawings, there is shown a small piece of fabric formed by warp knitting together a plurality of threads 2 b, c, etc.) in a warp knitting machine (not shown). The fabric 1 is in the form of netting having an array of holes H.

The warp threads 2 extend in the general direction of arrow A, and knit together at thread connections 3. The knitting produces loops 4 and underlaps 5 in the threads 2, in a manner well understood by those skilled in the relevant art. Although each thread 2 is represented by a monofilament, it will be 20 appreciated that two or more threads may be twisted or drawn together to form each such thread 2. The threads 2 are composed of any material suitable for the intended application of the fabric, for example plastic.

A drawstring 6 is laid in the fabric 1. In this embodiment, the drawstring 6 extends along the fabric in the general direction of the warp threads 2, and t weaves from one side to the other side of the fabric 1. Thus, as shown, the drawstring 6 has a length 6' which floats along on the one (front) side of the fabric 1 for several courses of thread connections 3, a short transitional length 6" which passes through a hole H between two adjacent thread underlaps and a successive length that floats or lays along the opposite (back) side of the fabric 1 for several further courses of thread connections 3, before another transitional section 6" passes through a hole H to the front side of the fabric 1 to commence repetition of the weave.

The drawstring 6 lies loosely on the fabric sides and passes freely through the fabric 1. In particular, the drawstring 6 is not captured between the W:*ake SPEC RNB48077 .doc loops 4 and underlaps 5, and does not form part of the thread connections 3.

As a result, the drawstring 6 can slide longitudinally relative to the fabric 1.

The drawstring lengths 6' and can vary depending upon the application to which the fabric 1 is to be put.

In this embodiment, the drawstring lengths 6' and are approximately the same. However, in alternative embodiments those lengths 6' and may differ so that, for example, the drawstring 6 is substantially entirely laid on one side of the fabric with occasional loops through the fabric 1 to the other side and about an underlap Fig. I, only one drawstring 6 is shown. However, two or more drawstrings 6 may be laid in the fabric 1, either together or in spaced apart relation.

In manufacturing the fabric 1 of Fig. 1, the warp threads are knitted together, and the drawstring 6 is laid in the threads 2, using a multi-bar warp knitting machine. The threads 2 are fed to the first (front) bars for knitting in the knit pattern shown, whilst the drawstring 6 is fed to the last (back) bar. The warp threads 2 may be loaded onto a beam section for feeding to the bars, or fed directly from their creels.

In machine operation, the thread bars move or "slog" across knitting 20 needles in a conventional knitting machine action. If the back bar carrying the drawstring 6 follows that movement of the thread bars, then the drawstring 6 will evade the adjacent thread overlap 5 being laid and will thus be placed over the top of that overlap. That in turn will cause the drawstring 6 to remain on the "back" (upper side as shown in Fig. 1) of the fabric 1, so that the fabric 1 will float or lay along the back side of the fabric 1. However, when the back bar does not slog with the thread bars then a thread underlap 5 will be laid over the drawstring 6, which will then be positioned on the "front" or "loop side" (lower side as shown in Fig. 1) of the fabric 1.

Fig. 2 of the drawings shows a fabric 1 in which the warp threads 2 are knitted together in a different knit pattern to the fabric of Fig. 1. Otherwise, the fabrics 1 are essentially the same, with a drawstring 6 being laid along the threads 2 so as to weave through holes H and avoid capture between the loops 4 and underlays W :Xk ekSPEC URN846077.d0c Referring now to Figs. 3 to 5, inclusive, there is shown schematic layouts of a plurality of warp threads 2 b, c etc.) in different knit patterns. For the sake of clarity, the threads 2 are arranged in spaced apart relation rather than being knitted together. In this way, it is possible to clearly see the relationship between the drawstring 6 and associated threads 2. Each thread 2 shows the loops 4 and underlaps 5 formed during knitting.

A drawstring 6 extends along one of the threads 2, avoiding the loops 4 so as to not be captured between the loops 4 and underlaps 5. As shown, the drawstring 6 has alternating lengths 6' which extend over the underlaps (representing movement of the drawstri.ng back bar with the warp thread bars in the knitting machine), and lengths which extend under the underlaps (representing movement of the thread bars along in the knitting machine). The drawstrings 6 have transitional lengths 6" which weave between adjacent underlaps 5, but are not connected to or caught by the threads 2. In Fig. 3, the transitional length 6" weaves three times between successive underlaps whilst in Figs. 4 and 5 the length 6" weaves once between adjacent underlaps In use, the fabric will undergo substantial stretching. In particular, the fabric 1 will stretch laterally of the warp thread direction, and contract in the 20 general direction of the warp threads. The drawstring 6 will move relative to the fabric 1 in order to accommodate that stretching.

The fabric 1 can be used as a canopy fabric in a covering structure. In that application, the drawstring 6 can be used in the support and tension of the fabric 1 on a frame. In that regard, the drawstring 6 can be retained in the fabric 1 and connected to the frame to achieve fabric support and tensioning.

Alternatively, the drawstring 6 can be used to draw a wire, cable or other heavier line through the fabric 1, which can then be used for support and tensioning of the fabric 1.

The process of the present invention provides for accurate and cost effective placement of a drawstring in warp knitted fabric during manufacture thereof.

Finally, it is to be understood that various alterations, modifications and/or additions may be made to the process and fabric without departing from the ambit of the present invention as defined in the claims appended hereto.

W:WateSPECrNRN846077C.d

Claims (17)

1. A process for warp knitting a fabric incorporating at least one drawstring, including: feeding a plurality of warp threads to a warp knitting machine in accordance with a predetermined knit pattern; knitting the warp threads together in the predetermined knit pattern to form a fabric with an array of thread connections; feeding at least one drawstring to the warp knitting machine; and, progressively laying in the drawstring through the warp threads during knitting thereof in a manner which avoids capture at the thread connections so that the draw string extends through the fabric in a general direction of the warp threads and can be moved longitudinally relative to the fabric.

2. A process as claimed in claim 1, wherein the warp thread connections include loops and underlaps, and the drawstring is laid in through the warp threads to avoid capture between the loops and underlaps.

3. A process as claimed in claim 1 or 2, wherein the drawstring is laid in through the warp threads so as to pass between opposite sides of the knitted *fabric.

4. A process as claimed in claim 3, wherein the drawstring is laid in through 20 the warp threads so as to extend along at least one side of the knitted fabric.

A process as claimed in claim 3 or 4, wherein the drawstring is laid in through the warp threads so as to extend alternatively along opposite sides of the knitted fabric for a predetermined number of courses of thread connections.

6. A process as claimed in claim 3 or 4, wherein the drawstring is laid in 0 0. 0 25 through the warp threads so as to extend substantially along one side of the 0..0 knitted fabric but intermittently loop through the fabric to the opposite side thereof. 0:060:

7. A process as claimed in claim 2 or any claim appended thereto, wherein laying in the drawstring through the warp threads includes passing the drawstring between thread underlaps so that the drawstring passes between opposite sides of the knitted fabric.

8. A process as claimed in any preceding claim, wherein the warp threads are fed to at least a front bar of the warp knitting machine for knitting, and the drawstring is fed to at least a back bar of the warp knitting machine for laying in. W:"e SPECJRNS46077.doc

9. A process as claimed in claim 8, wherein the warp threads are fed to at least two bars of the warp knitting machine.

A process as claimed in claim 8 or 9, wherein knitting the warp threads includes repetitively moving the bar(s), to which the warp threads are fed, across needles in the warp knitting machine, and laying in the drawstring includes selectively moving the bar to which the drawstring is fed, whereby when the drawstring bar is moved with the warp thread bar(s) the drawstring is placed on top of an underlap of a warp thread and so lies on one side of the knitted fabric, and when the drawstring bar is held against movement while the warp thread bar(s) moves then the drawstring is placed under an underlap of a warp thread and so lies on an opposite side of the knitted fabric.

11. A process as claimed in any preceding claim, wherein the drawstring is laid in along an edge region of the fabric.

12. A process as claimed in any preceding claim, wherein the warp threads are knitted in a predetermined knit pattern which produces a netting fabric having holes therethrough and the drawstring is laid in so as to pass through some of the holes.

13. A process for warp knitting a fabric incorporating at least one drawstring, substantially as hereinbefore described with reference to any one of the 20 embodiments illustrated in the accompanying drawings.

14. A warp knitted fabric incorporating at least one drawstring, manufactured using a process as claimed in any preceding claim.

A warp knitted fabric incorporating at least one drawstring, substantially as hereinbefore described with reference to any one of the embodiments illustrated in the accompanying drawings.

16. A warp knitting machine when used in a process according to any one of claims 1 to 13.

17. A warp knitting machine when used to manufacture a warp knitted fabric as claimed in claim 14 or DATED: 16 July 2001 PHILLIPS ORMONDE FITZPATRICK Attorneys for: 0f4B fe/^e, DAVID I LIAM KE V T W:kaTeSPECNIRN46077I. doc