Structural fabric and method for production thereof

Abstract

Formable stitched together precursor fabric made from weft and warp flat tapes of fiber-reinforced polymer on a weft insertion-stitching machine. The weft tape is supplied from a rotatable or stationary package that is pulled by a tension compensator that is driven in synchronism with an indexing carriage that wraps the tapes around continuously moving weft hooks. A constant tension on the tape is maintained. The weft tapes are stitched to the warp tapes, all in plane tapes having edges that abut substantially throughout the fabric.

1 . An elongated structural fabric comprising: 
 a first layer of substantially parallel fiber reinforced plastic warp tapes substantially aligned with the longitudinal axis of said fabric;    a second layer of substantially parallel fiber reinforced plastic weft tapes lying transverse to said axis; and    yarn looped around said warp tapes and said weft tapes so as to maintain said tapes in said aforesaid alignment.    
   
   
       2 . An elongated structural fabric according to  claim 1  wherein said warp and weft tapes are positioned such that at least one of said first layer and said second layer is substantially free of interstices.  
   
   
       3 . An elongated structural fabric according to  claim 2  wherein each of said first and second layers is substantially free of interstices.  
   
   
       4 . An elongated structural fabric according to  claim 3  wherein said edges of said warp tapes in said first layer and edges of said weft tapes in said second layer are in substantial abutment.  
   
   
       5 . An elongated structural fabric according to  claim 3  wherein edges of said warp tapes are in substantial abutment, and said weft tapes cross over themselves in a cross weft pattern.  
   
   
       6 . An elongated structural fabric according to  claim 1  wherein said warp and weft tapes are composed of fibers reinforced with a polymer.  
   
   
       7 . An elongated structural fabric according to  claim 6  wherein said fibers are glass fibers.  
   
   
       8 . An elongated structural fabric according to  claim 7  wherein said warp and weft tapes are positioned such that at least one of said first layer and said second layer is substantially free of interstices.  
   
   
       9 . An elongated structural fabric according to  claim 8  wherein each of said first and second layers is substantially free of interstices.  
   
   
       10 . An elongated structural fabric according to  claim 9  wherein edges of said warp tapes in said first layer and edges of said weft tapes in said second layer are in substantial abutment.  
   
   
       11 . An elongated structural fabric according to  claim 9  wherein edges of said warp tapes are in substantial abutment, and said weft tapes cross over themselves in a cross weft pattern.  
   
   
       12 . An elongated structural fabric according to  claim 1  wherein said weft tapes are substantially perpendicular to said axis.  
   
   
       13 . An elongated structural fabric according to  claim 12  wherein said warp and weft tapes are positioned such that at least one of said first layer and said second layer is substantially free of interstices.  
   
   
       14 . An elongated structural fabric according to  claim 13  wherein each of said first and second layers is substantially free of interstices.  
   
   
       15 . An elongated structural fabric according to  claim 14  wherein edges of said warp tapes in said first layer and edges of said weft tapes in said second layer are in substantial abutment.  
   
   
       16 . An elongated structural fabric according to  claim 14  wherein edges of said warp tapes are in substantial abutment, and said weft tapes cross over themselves in a cross weft pattern.  
   
   
       17 . An elongated structural fabric according to  claim 12  wherein said warp and weft tapes are composed of fibers reinforced with a polymer.  
   
   
       18 . An elongated structural fabric according to  claim 17  wherein said fibers are glass fibers.  
   
   
       19 . An elongated structural fabric according to  claim 18  wherein said warp and weft tapes are positioned such that at least one of said first layer and said second layer is substantially free of interstices.  
   
   
       20 . An elongated structural fabric according to  claim 19  wherein each of said first and second layers is substantially free of interstices.  
   
   
       21 . An elongated structural fabric according to  claim 20  wherein edges of said warp tapes in said first layer and edges of said weft tapes in said second layer are in substantial abutment.  
   
   
       22 . An elongated structural fabric according to  claim 20  wherein edges of said warp tapes are in substantial abutment, and said weft tapes cross over themselves in a cross weft pattern.  
   
   
       23 . A method of forming an elongated structural fabric comprising the steps of: 
 positioning a plurality of warp tapes in a first layer with said warp tapes substantially aligned with the longitudinal axis of said fabric;    locating a plurality of weft tapes in a second layer with said weft tapes lying transverse to said axis; and    looping yarn around said warp and weft tapes to maintain said warp tapes in substantial alignment with said axis and said weft tapes transverse to said axis.    
   
   
       24 . A method according to  claim 23  wherein said positioning step comprises the steps of pulling said warp tapes from a creel and feeding said warp tapes into a stitching head; and said locating step comprises the steps of pulling said weft tapes from a creel, over a tension compensator, and into an indexing carriage which feeds said weft tapes onto hooks which move said tapes into the stitching head.  
   
   
       25 . A method according to  claim 23  wherein said warp and weft tapes are positioned and located such that at least one of said first layer and said second layer is substantially free of interstices.  
   
   
       26 . A method according to  claim 25  wherein each of said first and second layers is substantially free of interstices.  
   
   
       27 . A method according to  claim 26  wherein edges of said warp tapes in said first layer and edges of said weft tapes in said second layer are in substantial abutment.  
   
   
       28 . A method according to  claim 26  wherein edges of said warp tapes are in substantial abutment, and said weft tapes cross over themselves in a cross weft pattern.  
   
   
       29 . A method according to  claim 23  wherein said warp and weft tapes are composed of fibers reinforced with a polymer.  
   
   
       30 . A method according to  claim 23  wherein said weft tapes are substantially perpendicular to said axis.  
   
   
       31 . A method according to  claim 30  wherein said warp and weft tapes are positioned such that at least one of said first layer and said second layer is substantially free of interstices.  
   
   
       32 . A method according to  claim 31  wherein each of said first and second layers is substantially free of interstices.  
   
   
       33 . A method according to  claim 32  wherein edges of said warp tapes are in substantial abutment, and said weft tapes cross over themselves in a cross weft pattern.  
   
   
       34 . A method according to  claim 32  wherein said warp and weft tapes are composed of fibers reinforced with a polymer.