WARP KNITTED TAPES

Abstract: A warp knitted tape including a ground knitted fabric comprising a plurality of knitted wales (18) formed from ground warp yarns and a plurality of weft yarn loops (19) extending across and being anchored by said knitted wales (18) a plurality of loops (2) projecting from one surface of the ground fabric, the loops being created from loop forming yarns (16) which are repeatedly knitted in with warp yarns along selected wales for a preselected number of courses and then floated across a preselected number of courses or wales before being knitted in again with the warp yarns along selected wales.

Description: WARP KNITTED TAPES The present invention relates to warp knitted tapes including a looped pile suitable for use in tape fasteners of the touch and close type. In touch and close tape fasteners, such for example VELCRO (RTM) type fasteners, one tape is provided with a pile comprising a plurality of protruding hook members and the other tape is provided with a pile comprising a plurality of projecting loops with which the protruding hook members can engage. It is known from UK Patent 2177597 to use a touch and close fastening tape for the hanging of draperies such as curtains. The present invention is particularly concerned with the provision of a warp knitted tape having a loop pile which can be used to enable the drapery to be hung as envisaged in UK patent 2177597. It will be appreciated that in addition the knitted tape of the present invention could be used in other fastening applications. According to one aspect of the present invention there is provided a warp knitted tape including a ground knitted fabric comprising a plurality of knitted wales formed from ground warp yarns and a plurality of weft yarn loops extending across and being anchored by said knitted wales, and a plurality of loops projecting from one surface of the ground fabric, the loops being created from loop forming yarns which are repeatedly knitted in with warp yarns along selected wales for a preselected number of courses and then floated across a preselected number of courses or wales before being knitted in again with the warp yarns along selected wales. The loop forming yarns may be extended when being floated across said preselected number of courses or wales in order to produce upstanding loops. Preferably, elasticated yarns are anchored to selected wales on the opposite face of the tape in order to cause the tape to contract on leaving the knitting machine and thereby cause said loops to project above said face. Preferably, each loop forming yarn is knitted in a single associated wale. According to another aspect of the invention there is provided a warp knitted tape including a ground fabric formed from a plurality of wales knitted from ground warp yarns and a plurality of ground weft yarn loops extending across and being anchored by said wales, and a plurality of loops projecting above one face of the ground fabric. Preferably, the plurality of loops are defined by loop forming yarns each of which is repeatedly knitted in with a warp yarn along a selected wale for a preselected number of courses and then floated across to a neighbouring wale to be knitted in with the warp yarn of said neighbouring wale for a predetermined number of courses. Preferably, the warp knitted tape is provided with one or more draw cords to enable the tape to be contracted into pleats. Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which :- Figure 1 is a schematic side view of a tape according to the present invention showing the front face of the tape Figure 2 is a schematic stitch diagram of the back face of the tape shown in Figure Figure 3 is a schematic stitch diagram of the front face of the tape shown in Figure 1 Figure 4 is a schematic side view of a tape according to another embodiment of the present invention Figure 5 is a plan view of the tape shown in Figure 4 Figure 6 is a schematic stitch diagram of portion VI of the tape shown in Figure IV Referring initially to Figure 1 there is shown a tape 10 formed from a ground warp knitted fabric 11 having a front face from which a plurality of loops 14 project. The loops 14 are of a size and project above the front face of the ground fabric by a sufficient amount to enable hook projections of a touch and close tape fastener to engage therewith. The loops 14 extend generally in the warp direction and are formed from loop forming yarns 16 (Figure 3) which are knitted in with the ground fabric 11. In Figures 2 and 3 an illustrative example of a ground fabric 11 is shown wherein a plurality of wales 18 are provided each of which is knitted from a ground warp yarn (not shown for clarity) . One or more weft yarns 19 (shown schematically by broken lines) extend across and are anchored to the wales 18 to form the ground fabric. A loop forming yarn 20 is knitted in with the ground warp yarn of selected wales for a preselected number of courses forming a first group of courses A and is then floated across a preselected number of courses forming a second group of courses B and the sequence is then repeated. A given loop forming yarn 20 preferably extends along a single wale 18. The number of courses forming group A is selected to provide adequate anchorage for the loops 14 to resist pulling forces created when detaching the associated velcro-type tape having hook projections. In the illustrated embodiment, group A is composed of two courses but it will be appreciated that the number of courses in Group A may be more or less than two. The number of courses in group B determines the length and thus the height of loops 14. Accordingly, the number of courses in group B are chosen to provide the desired height of loop. In the illustrated embodiment the number of courses in group B is five. In order to make the loops 14 pronounced the ground fabric 11 is preferably elasticated so as to be contractable in the warp direction. This is preferably achieved as schematically illustrated along selected wales 18 on the rear face of the ground fabric. The elasticated yarn 25 associated with a given wale is anchored at selected courses and is laid-in under a stretched condition so that on leaving the knitting machine the fabric is caused to contract in the wale-wise direction thereby bringing adjacent courses closer together and causing loops 14 to stand pronounced from the front face of the ground fabric. The loop forming yarn 20 is preferably a multi- filament yarn having a relatively high Decitex value, for example 1000 Dtex but a relatively low filament count, for example 50. Preferably the yarn 20 is a bulk continuous filament yarn so that each projecting loop 14 is defined by a plurality of individual filamentary loops. Preferably the multi-filament yarn is a polyamide yarn such as nylon (RTM) . In the tape illustrated in Figure 1, the loops 14 are arranged so as to cover substantially the entire front face of the ground fabric. It is envisaged that, if desired, the area of coverage of the loops 14 can be varied either across the width and/or length of the tape by appropriately varying the number of wales to which loop forming yarn is fed and/or number of courses in successive groups A. For example at regular intervals a selected group A of courses may be arranged to contain a large number of courses in order to create regions devoid of loops occuring at regular spacings along the length of the tape. The density of loops per unit area may be varied by suitable selection of the spacing between adjacent wales 18. If desired one or more draw cords may be incorporated in the ground fabric; the draw cords being used to create pleats and/or render the elasticated tape inextensible. A second embodiment according to the present invention is illustrated in Figures 4 to 6. The warp knitted tape 50 shown in Figure 4 is suitable for use as a curtain header and includes a ground fabric 51 which is formed from wales of knitted ground yarns 53 (not shown in Figure 4 and 5) across which weft yarns (not shown) extend and are anchored to the wales of warp yarns in a conventional manner. In the embodiment illustrated in Figure 4, three draw cords 58 are provided; each draw cord 58 extending freely across foldable regions F and being captively located in the intermediate non-foldable region S. Thus pulling of the draw cords 58 causes the foldable regions F to fold and thereby define pencil pleats P as schematically illustrated in Figure 5. Upstanding loops 60 are provided, at least in the regions S. The upstanding loops 60 are produced from loop forming yarns 62 (Figure 6) which are knitted along selected wales 53 throughout regions F and are knitted on alternating selected neighbouring wales throughout regions S. Thus, in Figure 6 an illustrative embodiment is shown wherein throughout each region S a loop forming yarn 62 is knitted in with the ground yarn on a first wale 53 for 2 consecutive courses, is then transferred to a second wale which in the illustration is the immediately adjacent wale, to be knitted in during the next 2 consecutive courses and is then transferred back to the first wale for knitting in with the next 2 consecutive courses; the sequence then being repeated. Each loop 60 is defined by the portion of yarn 66 which extends between the adjacent wales. During transfer the yarn portion 66 is laid across a loop forming finger in order to draw sufficient yarn to produce a loop of the desired height. The number of consecutive courses knitted inbetween the points of transfer from one wale to another is chosen in order to provide sufficient anchorage for each loop 60. The distance between adjacent first and second wales 58 is chosen to provide a desirable size of loop; in the illustrative embodiment the distance between adjacent wales is chosen to be approximately 3mm. As indicated above the loop forming yarn 62 is knitted in with selected warp yarns. For certain ground fabrics, for example the ground fabric 51 which is to be used as a curtain header tape, it is undesirable to incorporate a loop forming yarn having a relatively high decitex value since to do so causes the wales to become bulky in those regions where the loop forming and warp yarns are knitted together. This can cause undesirable distortions in the fabric. Accordingly, in order to avoid this type of deformation it is desirable to use a loop forming yarn having a decitex value which is sufficiently low to avoid undesirable deformation but yet when projecting above the surface provides sufficient density of loops 60 for co- operation with the hook-pile tape. To achieve this aim it is desirable to use a flat multi-filament yarn of about 220 dtex having about 10 filaments. This type of yarn also ensures that the loops 60 have sufficient rigidity to stand proud of the ground fabric. In order to ensure separation of the filaments making up each loop 60 it is envisaged that the loop pile is mechanically treated, for instance by brushing to create such separation. The multi-filament yarn is preferably a polyamide yarn. If desired the tape may be knitted without drawcords and may be knitted with the loops 60 extending continuously along the length of the tape.

Claims: CT.ATMS 1. A warp knitted tape including a ground knitted fabric comprising a plurality of knitted wales formed from ground warp yarns and a plurality of weft yarn loops extending across and being anchored by said knitted wales, a plurality of loops projecting from one surface of the ground fabric, the loops being created from loop forming yarns which are repeatedly knitted in with warp yarns along selected wales for a preselected number of courses and then floated across a preselected number of courses or wales before being knitted in again with the warp yarns along selected wales. 2. A warp knitted tape according to Claim 1, wherein the ground fabric is elasticated to cause the tape to contract in the warp direction on leaving the knitting machine and thereby cause said loops to project above said one surface. 3. A warp knitted tape according to Claim 2, wherein each loop forming yarn is knitted in a single associated wale. 4. A warp knitted tape according to Claim 1,2 or 3 wherein each loop forming yarn is a multi-filament yarn. 5. A warp knitted tape according to Claim 4, wherein the multi-filament yarn is a bulk continuous filament yarn. 6. A warp knitted tape according to Claim 1, wherein the plurality of loops are defined by loop forming yarns which in selected regions of the tape are each repeatedly knitted in with a warp yarn along a selected wale for a preselected number of courses, then floated across to a neighbouring wale to be knitted in with the warp yarn of said neighbouring wale for a predetermined number of courses and then floated across to the selected wale. 7. A warp knitted tape according to Claim 6 , wherein the loop forming yarn is a multi-filament yarn. 8. A warp knitted tape according to Claim 7 wherein the multi-filament yarn is a flat multi-filament yarn. 9. A warp knitted tape according to any preceding claim including one or more draw cords extending longitudinally of the tape. 10. A process for knitting a warp knitted tape comprising knitting a ground fabric including a plurality of knitted wales formed from ground warp yarns and a plurality of weft yarn loops extending across and being anchored by said knitted wales, and during knitting of said ground fabric creating a plurality of loops projecting from one surface of the ground fabric by knitting in loop forming yarns, each loop forming yarn being repeatedly knitted in with a warp yarn along a selected wale or course for a predetermined number of courses and then floated across a preselected number of courses or wales before being knitted in again with the warp yarn along a selected wale.

Inventors: ALLEN KENNETH ALFRED, ALLEN, KENNETH, ALFRED
Applicants: BRIGHTWAKE LTD, BRIGHTWAKE LIMITED
Application year: 1990
Main classification: D04B21
IPC codes: D04B21