This invention concerns a method of introducing at least one weft thread into a sheet of warp threads so as to assist in holding the sheet together, the said method comprising employing at least one toothed wheel which is rolled transversely across the sheet periodically to raise and lower predetermined warp threads in a sequence which permits the passage of the weft thread transversely of at least a part of the sheet, and introducing the said weft thread over and under the said predetermined warp threads.
A plurality of generally parallel, side-by-side warp tows of carbonaceous precursor material are interwoven with fill yarns forming a fabric of low density cross weave to facilitate handling of the warp tows for oxidation, carbonization and other processing thereof. A different fill yarn is interwoven with the warp tows from each of the opposite edges of the fabric so as to form a succession of generally V-shaped loops in each warp yarn with the loops of the two different warp yarns being staggered along the length of the fabric. Each loop of warp yarn is comprised of a pair of lengths of warp yarn which enter the fabric from spaced-apart locations along an edge of the fabric and undulate under and over the warp tows in a like sense which is opposite the sense of the undulations of the immediately adjacent loops prior to joining at a point across part but not all of the width of the fabric. When processing of the warp tows is completed, the fill yarns are easily removed simply by pulling on those portions of the fill yarns extending between the successive loops. Methods and apparatus for weaving the fabric employ spaced-apart members such as rotatable rollers for supporting the warp tows and reciprocating, out-of-phase heddle arrangement disposed between the rollers and engaging the warp tows to periodically momentarily lift alternate ones of the warp tows relative to the remaining warp tows and then momentarily lift the remaining ones of the warp tows relative to the alternate warp tows. Each time the warp tows are momentarily separated, a loop from each of the opposite fill yarns is placed between the separated warp tows such as by use of opposite rapier assemblies which employ hollow, elongated members for feeding in the warp yarns to form the loops.
A weave-de-weave process in which a plurality of weft loops are fluidly injected from opposite sides and normal to a plurality of warp yarns to form a composite tape. The tape is deweaved after the warp is space dyed by splitting the interior of the tape to expose the looped ends of the weft.
An apparatus and method for winding a sheet of aligned parallel yarns onto a beam is described. The beam winder utilizes a circularly arced yarn spool rack that feeds each yarn to an alignment comb through associated guide tubes. The distance between each spool of yarn and the alignment comb is substantially the same for all spools of yarn, thereby equalizing the force necessary to pull them to the comb. Next, the aligned sheet of material is preshrunk using heated rollers and wound onto a beam. Multiple speed controlled stepper motors are utilized to maintain a constant low level of tension in the sheet during the shrinking process. After shrinkage, the tension level of the yarn sheet is increased as it is wrapped onto the beam. A turntable that supports two or more beams is provided to facilitate the rapid switching of beams once one beam has become full.
An apparatus and method for winding a sheet of aligned parallel yarns onto a beam is described. The beam winder utilizes a circularly arced yarn spool rack that feeds each yarn to an alignment comb through associated guide tubes. The distance between each spool of yarn and the alignment comb is substantially the same for all spools of yarn, thereby equalizing the force necessary to pull them to the comb. Next, the aligned sheet of material is preshrunk using heated rollers and wound onto a beam. Multiple speed controlled stepper motors are utilized to maintain a constant low level of tension in the sheet during the shrinking process. After shrinkage, the tension level of the yarn sheet is increased as it is wrapped onto the beam. A turntable that supports two or more beams is provided to facilitate the rapid switching of beams once one beam has become full.
An apparatus and method for winding a sheet of aligned parallel yarns onto a beam is described. The beam winder utilizes a circularly arced yarn spool rack that feeds each yarn to an alignment comb through associated guide tubes. The distance between each spool of yarn and the alignment comb is substantially the same for all spools of yarn, thereby equalizing the force necessary to pull them to the comb. Next, the aligned sheet of material is preshrunk using heated rollers and wound onto a beam. Multiple speed controlled stepper motors are utilized to maintain a constant low level of tension in the sheet during the shrinking process. After shrinkage, the tension level of the yarn sheet is increased as it is wrapped onto the beam. A turntable that supports two or more beams is provided to facilitate the rapid switching of beams once one beam has become full.