WARP-KNIT TAPE FOR HOOK-AND-LOOP FASTENERS

Abstract: A warp-knit tape (10) for hook-and-loop fasteners comprises a pile portion (11) and selvage portions (12) extending on opposite longitudinal edges thereof, the pile portion (11) being constructed with pile threads (14), foundation threads (15) and laid-in weft threads (16). The pile threads (14) are knitted into a continuous chain of pile loops (P) each having a rise portion (P′) and a horizontally extending flat portion (P″) and linking in interlaced relation with adjacent loops (P).

Description: This invention relates to a hook-and-loop fastener comprising two layers of fabric which are releasably interengageable. One of the fabric layers carries hook- or mushroom-shaped male elements engageable with loop female elements on the other fabric layer. The present invention is concerned more particularly with the latter type of fabric which is formed by warp-knitting into a tape carrying thereon a multiplicity of pile-loops or female elements. Numerous hook-and-loop fasteners commonly known as velvet clasp fastener or more recently termed "surface-type fasteners" have been introduced in the art. A typical hook-and-loop fastener having a warp-knit support tape structure is disclosed in Japanese Patent Publication No. 57-381, in which threads are formed into individual, discrete pile-loops extending over or between rows of stitches and aloof from a foundation web as shown in Figure 5 of the accompanying drawings wherein the pile-loops are designated at P and the foundation web at F. A similar warp-knit surface-type fastener tape is disclosed in Japanese Patent Publication No. 55-38121, which tape comprises warp threads, weft threads, pile-loop threads P and elastic threads E, as shown in Figure 9 of the accompanying drawings. The elastic threads E serve to make the tape stretchable with pile-loops extending in floating relation to the foundation web in a manner similar to the tape disclosed in Japanese Patent Publication No. 57-381. Both of the above prior art warp-knit female tapes have a common drawback in that since the pile-loops are independent one from another and kept in free disposition, they are prone to tilt or otherwise become deformed; that is, they fail to retain the desired shape and position that have been afforded upon fabrication of the tape, resulting in insufficient or defective coupling engagement with the hook elements on the mating male tape. With the foregoing drawbacks of the prior art female or loop fastener tapes in view, the present invention seeks to provide an improved warp-knit female tape for a hook-and-loop fastener which is capable of retaining the shape and position best fit for its engagement with a male counterpart thereby providing a maximum of opportunity and strength of engagement of the loop elements with the hook elements on the respective tapes. The present invention further seeks to provide an improved warp-knit female fastener tape which is capable of fullest engagement with its male counterpart even in stretched condition. According to the present invention, a warp-knit tape for hook-and-loop fasteners, comprising a pile portion constructed with pile threads, foundation threads and laid-in weft threads, said pile threads being knitted into a continuous chain of pile loops each having a rise portion and a horizontally extending flat portion and linking in interlaced relation with adjacent loops. These and other objects and features of the invention will be better understood from the following detailed description taken in connection with the accompanying drawings which illustrate by way of example certain preferred embodiments of the invention. Figure 1 is a diagrammatic perspective view of a warp-knit loop or female fastener tape embodying the invention; Figure 2 schematically illustrates the construction of the warp-knit tape of Figure 1; Figures 3a, 3b and 3c are schematic diagrams of individual stitches constituting the system of the warp-knit tape of Figure 1; Figure 4 is a schematic side elevational view showing the pile-loops of the tape; Figure 5 shows a prior art fastener tape; Figure 6 is a diagrammetic perspective view of a modified form of warp-knit tape embodying the invention; Figu re 7 is a schematic diagram of the construction of the tape in Figure 6; Figures 8a - 8d are schematic diagrams of individual stitches constituting the system of the warp-knit tape of Figure 6; and Figure 9 shows another prior art fastener tape. Referring now to the drawings and Figure 1 in particular, there is shown on englarged scale a warp-knit tape 10 to be used as a loop or female part of a hook-and-loop fastener. The system of the tape 10 is diagrammatially illustrated in Figure 2 as consisting of a pile portion 11 and selvage portions 12 and 13 as extending longitudinally or warpwise on opposite edges of the pile portion 11, the tape system being formed suitably by a double Russel machine having front needles F and back needles B alternating over every other course. The pile portion 11 of the tape 10 shown in Figures 1 and 2 is constructed with pile threads 14 (Figure 3a), foundation threads 15 (Figure 3b) and laid-in weft threads 16 (Figure 3c). The pile threads 14 are knitted in the form of chain stitches of Link No. 2-0/0-2/2-0/0-2 or Link No. 2-0/0-2/0-2/2-0 as shown in Figure 3a. The pile threads 14 are knitted by back needles B together with weft threads 16 and foundation threads 15 to form a foundation web 17. The pile threads 14 are further knitted by front needles F into loops P of uniform size which are interlaced successively with ensuing loops P1, P2, P3 and so on to form a continuous chain of pile-loops extending over and along the wales 18 of the tape 10 as better shown in Figures 1 and 4, as a result of interlacing on intercrossing successive adjacent pile-loops P - P3, each of these pile-loops assumes substantially a form of double chain stitch having a rise portion P′ and a horizontally extending flat portion P″ and linking supportedly with adjacent pile-loops to provide a mechanically strong loop chain structure which is highly positionally stable and resistant to crushing out of shape. The resulting pile-loops P - P3 are further protected against dislocation or pluck-out by the foundation web 17 of the tape 10 in which the stitches of pile threads 14 and foundation threads 15 are interlaced with weft threads 16 which are in turn urged into place by the sinker loops of foundation threads 15. This knit structure precludes the necessity of resin coatings over the reverse face of the tape which is otherwise applied to prevent the pile-loops from falling off. Figures 6, 7 and 8a - 8d inclusive show another embodiment of the invention which is identical to the first embodiment described above in connection with Figures 1 - 4 except for the use of elastic threads 19 to make the tape system 10 stretchable as a whole. Each of the elastic threads 19, which may be of a synthetic rubber, spandex and other covered yarn, is formed by idle-swing into a laid-in warp of Link No. 0-0/0-0/2-2/2-2 without being knitted into any stitch as shown in Figure 8d. The elastic threads 19 may be laid in over each wale or every other wale, but should be stretched to some extent during knitting of the tape 10 and released upon take-off from the knitting machine to their original condition thereby holding the tape system shrunk as desired. There may be used a crimped yarn for the foundation thread 15, if desired, to provide increased stretchability of the tape 10. The selvages 12 and 13 extend over three wales on opposite longitudinal edges of the tape 10 as shown in Figures 2 and 7, and are adapted to be sewn or otherwise attached onto a garment article in a manner will known in the art. To prevent curl or deformation of the tape 10 along its selvages 12, 13, the latter may be thickened or reinforced further with chain stitches or tricot stitches.

Claims: 1. A warp-knit tape (10) for hook-and-loop fasteners, comprising a pile portion (11) constructed with pile threads (14), foundation threads (15) and laid-in weft threads (1 6), said pile threads (14) being knitted into a continuous chain of pile loops (P) each having a rise portion (P′) and a horizontally extending flat portion (P″) and linking in interlaced relation with adjacent loops (P). 2. A warp-knit tape for hook-and-loop fasteners according to claim 1, wherein said pile threads (14) are knitted in the form of chain stitches of Link No. 2-0/0-2/2-0/0-2 or Link No. 2-0/0-2/0-2/2-0. 3. A warp-knit tape for hook-and-loop fasteners according to claim 1, wherein stitches of said pile threads (14) and stitches of said foundation threads (15) are interlaced with said weft threads (16), said weft threads (16) being urged into place by sinker loops of said foundation threads (15). 4. A warp-knit tape for hook-and-loop fasteners according to claim 1, further including elastic threads (19) laid in said pile portion (11). 5. A warp-knit tape for hook-and-loop fasteners according to claim 4, wherein each of said elastic threads (19) is a laid-in warp of Link No. 0-0/0-0/2-2/2-2. 6. A warp-knit tape for hook-and-loop fasteners according to claim 4, wherein said elastic threads (19) extend in and along each wale at said pile portion (11). 7. A warp-knit tape for hook-and-loop fasteners according to claim 4, wherein said elastic threads (19) extend in and along every other wale at said pile portion (11). 8. A warp-knit tape for hook-and-loop fasteners according to claim 4, wherein said foundation threads (15) are crimped yarns.

Inventors: MATSUDA, YOSHIO
Applicants: YOSHIDA KOGYO K.K.
Application year: 1987
Main classification: D04B21
IPC codes: D04B21, A44B18