Abstract:
The corduroy fabric includes a plurality of transverse weft yarn sets. Each consists of at least three yarns and includes a plurality of pile yarn warp loops consisting of yarns having yarn forming at least one pile end, and a plurality of binding yarn warp loops consisting of at least two yarns. Each of the binding yarn warp loops is located respectively at two sides of a selected number of the pile yarn warp loops and has one common yarn winding a selected number of the pile yarn warp loops to form a binding yarn cross with the pile end. The pile yarn warp loops and the binding yarn warp loops of one transverse weft yarn set are crossly woven consecutively with longitudinal neighboring pile yarn warp stitches and the binding yarn warp loops of a next transverse weft yarn set to form a plurality of longitudinal warp loop pile zones.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a fabric formed by crocheting yarns through knitting needles and particularly to a corduroy fabric fabricated by a circular knitting machine. 
   BACKGROUND OF THE INVENTION 
   Corduroy fabrics generally have a greater thickness and a desirable warm-keeping characteristic, thus are suitable for making autumn and winter overcoats, and ornamental articles such as outer layers of shoes and hats, draperies, curtains, surface fabrics of sofas, and the like. There are many types of corduroy fabrics. Depending on the size of pile strips, they can be divided into extra fine strip, fine strip, medium strip, coarse strip, and broad strip. Other types also are available, such as with coarse strips and fine strips spaced alternatively, without cutting piles on a portion of the strips, or having the piles cut in a bias manner to form alternative heights on the strips, or the like. In general, the corduroy fabric is formed by weaving medium yarns. The ground fabric can adopt plain weave, twill weave, altered weft plain weave or the like. 
   The conventional corduroy fabric is fabricated by shuttle weaving. The fabric consists of one set of warp yarns and two sets of weft yarns woven manually or through semi-automatic machines. Referring to  FIGS. 1A and 1B  for a conventional V-shaped corduroy fabric fabricated by shuttle weaving with the pile yarns cut in a V-shape. It has a ground fabric formed by weaving one set of weft yarns (or called ground wefts  11  and  12 ) and warp yarns  21  and  22  to fasten piles, and another set of weft yarns (or called pile wefts  911  and  912 ) and the warp yarns  21  and  22  woven to form regular float wefts  971  and  972 . The float wefts  971  and  972  are cut to form V-shaped piles  921  and  922 . Then the pile wefts  911  and  912  are cut and the V-shaped piles  921  and  922  direct upwards in V-shape. Hence the fabric surface forms a plurality of longitudinal pile strips  2912  which have a cross section like lamp wicks to become a corduroy fabric. 
   The fabric shown in  FIG. 1A  adopts a 1:2 plain weaving ground. The ground fabric is formed by weaving consecutively two pile wefts  911  and  912  for every woven ground weft  11 , and the warp yarns  21  and  22 , and the ground wefts  11  and  12  are woven to form the ground fabric so that the pile wefts  911  and  912  have a regular length (generally at a length of 5-6 warp yarns) floating on the fabric surface. Referring to  FIG. 1B , after the pile wefts  911  and  912  have been cut, the piles  921  and  922  are formed in a V-shape and fastened by the ground fabric (formed by the warp yarns  21 ,  22 , and weft yarns  11  and  12 ). As the V-shaped piles  921  and  922  are fastened to the ground fabric at a few cross weaving spots formed by the warp yarns  21  and  22 , the V-shaped piles  921  and  922  are easily loosened off. Hence such a weaving method is generally adoptable to a broad strip corduroy fabric with a high weft density. Ii usually is woven manually or through semi-automatic machines. As a result, production efficiency is lower. 
   Refer to  FIG. 2  for another type of conventional corduroy fabric with a W-shaped pile structure. It also adopts a 1:2 plain weaving ground. It has a ground fabric formed by weaving one weft yarn  13  and two consecutive pile wefts  23  and  24  (no mark in the drawing), and weaving warp yarns  23 ,  24 ,  25  and  26  and ground wefts  13  and  14  so that the pile weft has a regular length (generally at a length of 4-5 warp yarns) floating on the fabric surface. After cut, the pile wefts form W-shaped piles  981  and  982  clipped by the ground fabric (formed by the warp yarns  23 ,  24 ,  25  and  26 , and the ground wefts  13  and  14 ). The W-shaped piles  981  and  982  and the warp yarns are woven with a greater number of crossed spots, thus can form a more secured fastening than the V-shaped piles. It generally is suitable for fabricating medium strip or fine strip corduroy fabrics. But fabricated by the conventional shuttle weaving, the resulting W-shaped piles  981  and  982  still could loosen off, and production efficiency still is not desirable. 
   In short, the conventional corduroy fabrics fabricated by shuttle weaving, either with V-shaped or W-shaped piles, still have common problems remained to be overcome, notably: 
   1. the piles easily loosen off; and 
   2. production efficiency is too low. 
   SUMMARY OF THE INVENTION 
   Therefore the primary object of the present invention is to solve the aforesaid problems by providing a corduroy fabric that has piles fastened more securely and can be fabricated at a higher production efficiency. 
   To achieve the foregoing object the corduroy fabric according to the invention is fabricated through a circular knitting machine. Its structure includes a plurality of transverse weft yarn sets consisting of at least three yarns. Each of the transverse weft yarn sets includes a plurality of pile yarn warp loops consisting of at least two yarns in which at least one yarn in the pile yarn warp loops has at least one pile end, and a plurality of binding yarn warp loops consisting of at least two yarns. Each binding yarn warp loop is located at two sides of a selected number of the pile yarn warp loops. At least one common yarn winds around the selected number of pile yarn warp loops to form a binding yarn woven with the pile end in a staggered fashion. The pile yarn warp loop and the binding yarn warp loop of the transverse weft yarn set further are woven consecutively with the pile yarn warp loop and the binding yarn warp loop of a longitudinal neighboring transverse weft yarn set to form a plurality of longitudinal warp loop pile zones. 
   The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a schematic view of a conventional V-shaped corduroy fabric structure fabricated by shuttle weaving. 
       FIG. 1B  is schematic view according to  FIG. 1A  with the pile yarns cut in a V-shape. 
       FIG. 2  is a schematic view of another conventional corduroy fabric structure with the piles formed in a W-shape. 
       FIG. 3A  is a fragmentary schematic view of a first type structure of the corduroy fabric of the invention. 
       FIG. 3B  is a fragmentary enlarged view according to  FIG. 3A . 
       FIG. 4A  is a fragmentary schematic view of the knitting fabric structure of a corduroy fabric of the invention. 
       FIG. 4B  is a fragmentary schematic view according to  FIG. 4A  showing a cutting pattern. 
       FIG. 5A  is a fragmentary schematic view of a second type structure of the corduroy fabric of the invention. 
       FIG. 5B  is a fragmentary enlarged view according to  FIG. 5A . 
       FIG. 6  is a fragmentary schematic view of a third type structure of the corduroy fabric of the invention 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The corduroy fabric of the present invention is fabricated through a circular knitting machine. The operation principle and techniques of the circular knitting machine is known in the art, and form no part of the invention. Thus their details are not shown in the drawings and also not marked or discussed hereinafter. 
   Refer to  FIGS. 3A and 3B  for the fragmentary schematic view of a first type structure of the corduroy fabric of the invention. In the drawings only a fabric consisting of two sets of transverse weft yarn sets  3  and  6  is marked with numerals for discussion. 
   As shown in the drawings, the transverse weft yarn set  3  includes three yarns  31 ,  32  and  33 , and is crocheted separately by needles of a circular knitting machine to form a plurality of pile yarn warp loops  4312  and  5312 , and a plurality of binding yarn warp loops  4323  and  5323 . In one longitudinal warp loop pile zone  9  one pile yarn warp loop  4312  and another pile yarn warp loop  5312  have two yarns  31  and  32 . The two yarns  31  and  32  of the pile yarn warp loop  4312  is obtained by two crochets of one needle, while the two yarns  31  and  32  of the pile yarn warp loop  5312  is obtained by two crochets of another needle. The yarn  31  has a pile end  311 . The binding yarn warp loops  4323  and  5323  also have two yarns  32  and  33  located respectively on the left side of the pile yarn warp loop  4312  and the right side of another pile yarn warp loop  5312 . The two yarns  32  and  33  of the binding yarn warp loop  4323  are obtained by two crotches of a needle different from the one of the pile yarn warp loops  4312  and  5312 . And the two yarns  32  and  33  of another binding yarn warp loop  5323  are obtained by two crotches of one needle different the ones previously discussed. The binding yarn warp loops  4323  and  5323  have a common yarn  33 , winding the pile yarn warp loops  4312  and  5312  to form a binding yarn  333  cross with its own pile end  311 . 
   Another transverse weft yarn set  6  also includes three yarns  61 ,  62  and  63 , and is crocheted separately by needles of the circular knitting machine to form a plurality of pile yarn warp loops  4612  and  5612 , and binding yarn warp loops  4623  and  5623 . As previously discussed, in the same longitudinal warp loop pile zone  9  mentioned above, one pile yarn warp loop  4612  and another pile yarn warp loop  5612  have two yarns  61  and  62 . The two yarns  61  and  62  of the pile yarn warp loop  4612  is obtained by two crochets feeding under the transverse weft yarn set  6  through the same needle which forms the pile yarn warp stitch  4312  previously discussed, while the two yarns  61  and  62  of another pile yarn warp loop  5612  is obtained by two crochets feeding under the transverse weft yarn set  6  through the same needle which forms another pile yarn warp loop  5312  previously discussed. The yarn  61  also has a pile end  611 . The binding yarn warp loops  4623  and  5623  also have two yarns  62  and  63  located respectively on the left side of the pile yarn warp loop  4612  and the right side of another pile yarn warp loop  5612 . The two yarns  62  and  63  of the bind yarn warp stitch  4623  are obtained by two crotches feeding under the transverse weft yarn set  6  through the same needle which forms the binding yarn warp loop  4323  previously discussed. And the two yarns  62  and  63  of another binding yarn warp loop  5623  are obtained by two crotches feeding under the transverse weft yarn set  6  through the same needle which forms the binding yarn warp loop  5323  previously discussed. The binding yarn warp loops  4623  and  5623  have a common yarn  63 , winding the pile yarn warp loops  4612  and  5612  to form a binding yarn  633  cross with its own pile end  611 . 
   It is to be noted that the two yarns  61  and  62  of the pile yarn warp loop  4612  are obtained through the same needle forming the pile yarn warp loop  4312 , that receives yarn feeding while being moved to a yarn outlet of the transverse weft yarn set  6  and crochets two times, then the needle releases the yarns  31  and  32  of the pile yarn warp loop  4312  from a yarn release ring. Hence the yarns  61  and  62  of the pile yarn warp loop  4612  pass through the yarns  31  and  32  of the pile yarn warp loop  4312  to form a consecutive cross weaving fashion. And the two yarns  61  and  62  of the pile yarn warp loop  5612  are obtained by the same needle forming the pile yarn warp loop  5312 , that receives yarn feeding while being moved to a yarn outlet of the transverse weft yarn set  6  and crochets two times, then the needle releases the yarns  31  and  32  of the pile yarn warp loop  5312  from a yarn release ring. Hence the yarns  61  and  62  of the pile yarn warp loop  5612  pass through the yarns  31  and  32  of the pile yarn warp loop  5312  to form a consecutive cross weaving fashion. Thus, the needles are continuously moved to the next yarn outlet to feed the yarns and crochet the yarns separately. As a result, a consecutive cross weaving is proceeded to form a plurality of longitudinal warp pile zones  9  to become the corduroy fabric of the invention. 
   Compared with the conventional techniques the present invention provides the following advantages: 
   1. The pile end of the pile yarn warp loop of the corduroy fabric of the invention is bound by the binding yarn of the binding yarn warp loop, hence the problem of pile loosening occurred to the conventional corduroy fabric does not take place. 
   2. The corduroy fabric of the invention is fabricated through a circular knitting machine, thus production speed is faster and the production efficiency is higher than the conventional shuttle weaving. 
   Refer to  FIG. 4A  for a fragmentary schematic view of the knitting fabric structure of a corduroy fabric of the invention. It is the anterior fabric structure of the corduroy fabric shown in  FIGS. 3A and 3B  after being knitted through the circular knitting machine. It is to be noted that the longitudinal warp loop pile zone  9  of each of the transverse weft yarn sets  3  and  6  has a float yarn  3111  and  6111 . The binding yarn warp loops  4323 ,  5323 ,  4623  and  5623  have a common yarn  63  winding the pile yarn warp loops  4312  and  4612 , and  5312  and  5612  to form the binding yarns  333  and  633 . As the needle foot crocheted to form the pile yarn warp loops  4312 ,  5312 ,  4612  and  5612  and the needle foot crocheted to form the bind yarn warp stitches  4323 ,  5323 ,  4623  and  5623  travel on different tracks of a cam, hence the cam of the needles of the pile yarn warp loops  4312 ,  5312 ,  4612  and  5612  can be designed in a regular cycle on a plain track without crocheting the yarns  33  and  63  to form the binding yarns  333  and  633 . And the cam of the needles of the pile yarn warp loops  4323 ,  5323 ,  4623  and  5623  can be designed in a regular cycle on a plain track without crocheting the yarns  31  and  61  to form the float yarns  3111  and  6111 . The binding yarns  333  and  633 , and the float yarns  3111  and  6111  can be designed to cross each other as shown in  FIG. 4B . After the float yarns  3111  and  6111  are cut to form the pile ends  3111  and  611 , they also are bound by the binding yarns  333  and  633 , thus are fastened securely and less likely to loosen off. 
   Refer to  FIGS. 5A and 5B  for a fragmentary schematic view of a second type structure of the corduroy fabric of the invention. It is substantially the same as the one shown in  FIGS. 3A and 3B . The main difference is as follow: 
   In the drawings the fabric formed by two transverse weft yarn sets  3  and  6  also are marked for discussion. The transverse weft yarn set  3  includes three yarns  31 ,  32  and  33 , and is crocheted separately by needles of a circular knitting machine to form a plurality of pile yarn warp loops  9312  and a plurality of binding yarn warp stitches  4323  and  5323 . In one longitudinal warp loop pile zone  91 , one pile yarn warp loop  9312  has two yarns  31  and  32  formed by two crochets of one needle. One yarn  31  has two pile ends  311 . The bind yarn warp loops  4323  and  5323  also have two yarns  32  and  33  located respectively on the left and right sides of the pile yarn warp loop  9312 . The two yarns  32  and  33  of the binding yarn warp loop  4323  are obtained by two crotches of one needle different from the one of the pile yarn warp loop  9312 . The two yarns  32  and  33  of the binding yarn warp stitch  5323  are obtained by two crotches of one needle different the ones previously discussed. The binding yarn warp loops  4323  and  5323  have a common yarn  33 , winding the pile yarn warp loop  9312  to form a binding yarn  333  cross with the two pile ends  311 . 
   Another transverse weft yarn set  6  also includes three yarns  61 ,  62  and  63 , and is crocheted separately by needles of the circular knitting machine to form a plurality of pile yarn warp loops  9612 , and binding yarn warp loops  4623  and  5623 . Like those previously discussed, in one longitudinal warp loop pile zone  91  one pile yarn warp loop  9612  has two yarns  61  and  62 . The two yarns  61  and  62  of the pile yarn warp loop  9612  are obtained by two crochets feeding under the transverse weft yarn set  6  through the same needle which forms the pile yarn warp loop  9312  previously discussed. One yarn  61  has two pile ends  611 . The binding yarn warp loops  4623  and  5623  also have two yarns  62  and  63  located respectively on the left and right sides of the pile yarn warp loop  9612 . The two yarns  62  and  63  of the binding yarn warp stitch  4623  are obtained by two crochets feeding under the transverse weft yarn set  6  through the same needle of the binding yarn warp stitch  4323  previously discussed. The two yarns  62  and  63  of the binding yarn warp stitch  5623  are obtained by two crochets feeding under the transverse weft yarn set  6  through the same needle of the binding yarn warp loop  5323  previously discussed. The two binding yarn warp loops  4623  and  5623  have a common yarn  63 , winding the pile yarn warp loop  9612  to form a binding yarn  633  cross with the two pile ends  611 . 
   It is to be noted that the two yarns  61  and  62  of the pile yarn warp loop  9612  are obtained by the same needle forming the pile yarn warp loop  9312 , that receives yarn feeding at a yarn outlet of the transverse weft yarn set  6  and crochets two times, then the needle releases the yarns  31  and  32  of the pile yarn warp stitch  9312  from a yarn release ring. Hence the yarns  61  and  62  of the pile yarn warp stitch  9612  pass through the yarns  31  and  32  of the pile yarn warp loop  9312  to form a consecutive cross weaving fashion. Thus, the needles are continuously moved to the next yarn outlet to feed the yarns and crochet the yarns. As a result, a consecutive cross weaving is proceeded to form a plurality of longitudinal warp pile zones  91  to become the corduroy fabric of the invention. 
   Refer to  FIG. 6  for a fragmentary schematic view of a third type structure of the corduroy fabric of the invention. The longitudinal warp loop pile zone  9  is the same as the one shown in  FIG. 3B . Alterations can be seen in  FIG. 6 . The transverse weft yarn set  3  has a spaced yarn warp loop  7323  consisting of two yarns  32  and  33 . The spaced yarn warp loop  7323  is located between the binding yarn warp loops  5323  and  4323 . The other transverse weft yarn set  6  also has a spaced yarn warp loop  7623  consisting of two yarns  62  and  63 , and being located between the binding yarn warp loops  5623  and  4623 . The yarns  62  and  63  of the spaced yarn warp loop  7623  pass through the yarns  32  and  33  of the other spaced yarn warp stitch  7323  to form a consecutive cross weaving fashion. 
   While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. 
   Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.