Hill US005085252A United States Patent (19) 11) Patent Number: 5,085,252 Mohamed et al. 45) Date of Patent: Feb. 4, 1992

(54) METHOD OF FORMING VARIABLE CROSS-SECTIONAL SHAPED OTHER PUBLICATIONS THREE-DMENSONAL FABRICS M. Mohamed and Z. Zhang, " of 3-D Pre forms', Fibertex Conference, Greenville, S.C., (Sep. (75) Inventors: Mansour H. Mohamed, Raleigh, 13-15, 1988). N.C.; Zhong-Huai Zhang, Shanghai, M. Mohamed, Z. Zhang, "Manufacture of Multi-Layer China Woven Preforms', The American Society of Mechani (73) Assignee: North Carolina State University, cal Engineers, 81-99 (Nov.-Dec., 1988). Raleigh, N.C. M. Mohamed, Z. Zhang and L. Dickinson, "3-D Weav ing of Net Shapes”, The Japaneses International Sampe (21) Appl. No.: 574,693 Symposium, 1487-1494 (Nov. 28-Dec. 1, 1989). 22 Filed: Aug. 29, 1990 Primary Examiner-Andrew M. Falik 5ll Int. Cl...... D03D 41/00; D03D 47/04; Attorney, Agent, or Firm-Richard E. Jenkins DO3D 13/OO 57 ABSTRACT 52 U.S. C...... 139/22; 139/11; Method of weaving a variable cross-sectional shaped 139/DIG. 1 three-dimensional fabric which utilizes different weft (58) Field of Search ...... 139/22, 11, 457, DIG. 1, insertion from at least one side of the warp layers 139/408, 411 for selectively inserting weft into different por (56) References Cited tions of the fabric cross-sectional profile defined by the warp yarn layers during the weaving process. If in U.S. PATENT DOCUMENTS serted from both sides of the warp yarn layers, the weft 3,834,424 9/1974 Fukuta et al. . yarns may be inserted simultaneously or alternately 3,884,429 5/1975 Dow ...... 39/DIG. 1 from each side of the warp yarn layers. The vertical 3,993,817 11/1976 Schultz yarn is then inserted into the fabric by reciprocation of 4,001,478 1/1977 King . 4,03,922 6/977 Trost et al...... 139/11 a plurality of harnesses which separate the vertical yarn 4,066,104 1/1978 Halton et al. .. 139/DIG. into a plurality of vertical yarn systems as required by 4,526,026. 7/1985 Knauland, Jr...... 139/22 the shape of the three-dimensional fabric being formed. 4,615,256 10/1986 Fukuta et al. . 4,712,588 12/1987 Sainen ...... 39/309 14 Claims, 10 Drawing Sheets

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5,085,252 2 yarn ends to the arms of subsequent carriers. In this METHOD OF FORMING WARIABLE fashion, the two component yarns transferred by the CROSS-SECTIONAL SHAPED carrier arms are suitably displaced and zig-zagged rela THREE-OMENSIONAL FABRICS tive to the remaining component yarn so as to facilitate the selection of weaving patterns to form the fabric in GOVERNMENT INTEREST the shape of cubes, hollow angular columns, and cylin This invention was made with Government support ders. under Grant No. NAGW-1331 awarded by the Na Another type of orthogonally woven reinforcing tional Aeronautics and Space Administration (NASA). structure is disclosed by U.S. Pat. No. 3,993,817 to The Government has certain rights in this invention. 10 Schultz et al. The apparatus disclosed by Schultz et al. fabricates a woven structure from axial, radial, and TECHNICAL FIELD circumferential sets of threads. The radial threads are The present invention relates to three-dimensional drawn from and passed through aligned woven fabric formed of warp, weft and vertical yarns, guides in successive disks which are arranged about a and more particularly to a method for forming three-di 15 common central axis and slightly spaced from each mensional woven fabrics of different cross sections and other axially. A circumferential thread is drawn from a the fabric produced thereby. and passed in a loop between each of two disks outside of the radial threads, and several turns of it are BACKGROUND ART thus wrapped and the loop tightened to draw the radial The use of high-performance composite fiber materi 20 threads inwardly. When the desired number of circum als is becoming increasingly common in applications ferential threads in a given layer have been wrapped such as aerospace and aircraft structural components. between each pair of disks, axial threads are then As is known to those familiar with the art, fiber rein threaded between adjacent radial threads by leading forced composites consist of a reinforcing fiber such as them through with a needle, and further wraps carbon or KEVLAR and a surrounding matrix of ep 25 of circumferential threads may be applied. In this partic oxy, PEEK or the like. Most of the composite materials are formed by laminating several layers of fabric, ular orthogonal structure, the axial threads are straight by filament winding, or by cross-laying of tapes of con and axially extending while the radial threads lie partly tinuous filament fibers. However, all of the structures normal to and partly parallel to the axial threads. The tend to suffer from a tendency toward delamination. 30 circumferential threads are wrapped normal to the axial Thus, efforts have been made to develop three-dimen threads and in an interlaced relationship between and sional braided, woven and knitted preforms as a solution around the radial threads and upon and beneath the to the delamination problems inherent in laminated axial threads. composite structures. Other known methods for forming three-dimensional For example, U.S. Pat. No. 3,834,424 to Fukuta et al. 35 structures include the AUTOWEAVE BR900 and discloses a three-dimensional woven fabric as well as BR2000 systems developed by Brochier in France and method and apparatus for manufacture thereof. The installed at Avco Specialty Materials/Textron facility Fukuta et al. fabric is constructed by inserting a number in Lowell, Mass. The computerized process entails in of double filling yarns between the layers of warp yarns serting radial rods into a foam mandrel machined to and then inserting vertical yarns between the rows of 40 conform to the inside shape of the final product and warp yarns perpendicularly to the filling and warp yarn forming helical tapered corridors therein. Axial yarns directions. The resulting construction is packed to are fed into the axial corridors by a shuttle and circum gether using a reed and is similar to traditional weaving ferential yarns are wound into the circumferential corri with the distinction being that "filling" yarns are added dors to anchor the previously positioned axial yarns so in both the filling and vertical directions. Fukuta et al. 45 that the alternating axial yarn and circumferential yarn essentially discloses a three-dimensional orthogonal placement produces layers which are used to build up woven fabric wherein all three yarn systems are mutu the preformed wall thickness. U.S. Pat. No. 4,001,478 to ally perpendicular, but it does not disclose or describe King discloses yet another method to form a three-di any three-dimensional woven fabric having a configura mensional structure wherein the structure has a rectan tion other than a rectangular cross-sectional shape. This 50 gular cross-sectional configuration as well as a method is a severe limitation of Fukuta et al. since the ability to of producing cylindrical three-dimensional shapes. form a three-dimensional orthogonal weave with differ ently shaped cross sections (such as , , , and II) is DISCLOSURE OF THE INVENTION very important to the formation of preforms for fibrous In accordance with the present invention, applicants composite materials. Applicants have overcome this 55 provide a three-dimensional weaving method for pro shortcoming of Fukuta et al. by providing a three-di duction of orthogonal fabrics having a variety of prede mensional weaving method which provides for differ termined and variable cross-sectional shapes. A desired ential weft insertion from both sides of the fabric forma predetermined cross section three-dimensional fabric is tion zone so as to allow for an unexpectedly and surpris formed by repeating a cycle of operation which com ingly superior capability of producing three-dimen prises the steps of providing a plurality of layers of sional fabric constructions of substantially any desired warp yarns which are in horizontal and vertical align cross-sectional configuration. ment and maintained under tension, said layers of warp Also of interest, Fukuta et al. U.S. Pat. No. 4,615,256 yarns defining a variable predetermined cross-sectional discloses a method of forming three-dimensionally lat shape; selectively inserting a plurality of weft yarns ticed flexible structures by rotating carriers around one which are connected by a loop at the respective fore component yarn with the remaining two component ends thereof into spaces between said layers of warp yarns held on bobbins supported in the arms of the yarn, said weft yarns being inserted a predetermined carriers and successively transferring the bobbins or and non-uniform horizontal distance from at least one 5,085,252 3 4. side of said warp yarn cross-sectional shape in accor FIG. 8 is a schematic top view showing the reed dance with the shape of the fabric being formed; thread moving forwardly to the fell of the three-dimensional ing binder or selvage yarn through the loops at the fore fabric and the fabric beat-up motion; ends of said weft yarns; bringing a reed into contact FIG. 9 is a schematic side view corresponding to with the fell of the fabric being formed; and inserting FIG. 8 and prior to the reciprocation of the harnesses vertical yarns into spaces between vertically aligned and to the fabric being taken-up and the reed moving rows of warp yarns in a direction substantially perpen back to its original position so as to complete the weav dicular to both said yarns, said vertical ing cycle; and yarns being selectively threaded through a plurality of FIG. 10 is a schematic view of selvage yarn being harnesses so as to be separated into a predetermine d 10 inserted into the fore end loops formed by the weft plurality of vertically movable yarn systems by said yarns during the fabric formation process of the present harnesses in accordance with the shape of the fabric invention. being formed, and said yarn systems being selectively BEST MODE FOR CARRYING OUT THE vertically moved by said harnesses to insert said vertical 15 INVENTION yarns into said fabric being formed. Three-dimensional woven fabrics are presently It is therefore the object of this invention to provide formed by arranging warp yarns in multiple layers de a method of weaving a variable cross section three-di fining sheds therebetween. A plurality of needles con mensional fabric in accordance with a desired predeter taining doubled filling or weft yarns are simultaneously mined cross-sectional shape. inserted a uniform distance into the warp sheds fron It is another object of the present invention to pro one side thereof. The filling yarns are held on the oppo vide a method for weaving a three-dimensional woven site side of the warp sheds by a catch yarn which passes fabric which is not limited to a rectangular cross-sec through the loops of the doubled weft or filling yarns tional shape. and thus forms the fabric selvage. The weft needles are It is another object of the present invention to pro- 25 then returned to their original position at one side of the vide a method for weaving a three-dimensional woven warp yarn sheds after inserting the doubled filling fabric with improved vertical yarn insertion. yarns, and a reed is urged forwardly to beat-up and pack It is another object of the present invention to pro the yarns into a tight structure at the fell of the fabric. vide a method for weaving three-dimensional woven Next, a layer of vertical yarns is inserted into the fell of fabrics from carbon fibers with pneumatic actuators in 30 the three-dimensional fabric, and the reed is returned to lieu of electric motors so as to prevent electrical short its original remote position so that the entire weaving ing-out problems associated with electric motors in cycle may be repeated. Unfortunately, this type of proximity to carbon fibers being constructed into a three-dimensional fabric formation does not allow for fabric. the formation of integrally woven fabric constructions It is yet another object of the present invention to 35 with variable cross-sectional shapes. provide a method for differential length weft yarn by Applicants have overcome the limitations of the prior inserting weft yarns from either or both sides of the art in forming integral variable cross-sectionally-shaped fabric formation zone during three-dimensional weav three-dimensional fabrics through the method of the ing so as to form a three-dimensional woven fabric present invention which provides for insertion of a having a predetermined and variable complex cross-sec plurality of different length weft yarns from one or both tional shape. sides of the warp yarn sheds. This weft insertion feature Some of the objects of the invention having been when combined with applicants' provision of warp yarn stated, other objects will become evident as the descrip layers in horizontal and vertical alignment so as to de tion proceeds, when taken in connection with the ac fine the predetermined desired cross-sectional shape of 45 the fabric provides for unique flexibility in forming companying drawings described hereinbelow. multiple and complex cross-sectional shapes for three BRIEF DESCRIPTION OF THE DRAWINGS dimensional woven fabrics. Moreover, applicants' use of harnesses in order to insert the vertical yarn into the FIG. 1 is a computer timing diagram of the weaving fabric provides for a tight insertion of vertical yarn steps of a method for forming three-dimensional fabrics whether extending for a long or short vertical portion according to the present invention; of the cross-sectional shape of the fabric. FIG. 2 is a key to the numbered steps shown in the Applicants contemplate that all mechanical motions timing diagram of FIG. 1; of the process other than fabric take-up should most FIG.3 shows a schematic side view of the process of suitably be pneumatically actuated so as to minimize the present invention at the beginning of the fabric problems associated with weaving carbon fibers in the formation cycle; presence of conventional electric motors. The take-up FIG. 4 shows a schematic top view corresponding to motion in the instant process may most suitably be ac FIG. 3; complished by an electrical stepper motor and worm FIG. 5 shows a schematic front view corresponding gear which positions the electric motor at a safe remote to FIG. 3; SO position from the fabric weaving process. Given the FIG. 6 shows a schematic top view of the process of general description of the applicants' invention set forth the present invention with weft insertion simulta above and with reference now to FIGS. 1-10 of the neously occurring from both sides of the fabric forma drawings, applicants now will describe the specific tion zone; details of the invention which will be clearly under FIG. 7 shows a schematic top view of the weft yarn 65 standable to one skilled in the art of three-dimensional insertion needles withdrawing to their original positions fabric formation. on each side of the yarn formation zone and thereby Referring to FIG. 1 of the drawings which diagram forming fore end loops; natically shows a timing diagram of a three-dimen 5,085,252 5 6 sional weaving process according to the present inven locked so that the filling yarn and selvage yarn will be tion, a cycle of the weaving process is divided into properly tensioned during the weaving process. several different motions. The key to the numeral desig Next, two opposing sets of filling needles 2 insert nated motions shown in the timing diagram of FIG. 1 is filling yarns Y1 and Y2 between the warp yarn layers. shown in FIG. 2 and is also set forth below for a better 5 One set of needles carrying the Y1 weft yarns goes understanding of the invention. It should be noted that through the flange portion of the warp yarn defined applicants prefer that the weaving process be controlled design and the other set of needles carrying the Y2 weft by a suitably programmed personal computer, but other yarns goes through the web portion (see FIGS. 5 and 6). control mechanisms can be utilized and would be appar Subsequent to filling yarn insertion, two selvage needles ent to one skilled in the art. The timing numeral key O 3 are raised up to the position shown in phantom line in (and timing sequence) is as follows: FIG. 3, and selvage hoid rod 4 is moved inwardly to the position shown in FIG. 6. (Selvage hold rod 4 serves to Number Motion the space between selvage needles 3 and the Filling Lock and Selvage Lock selvage yarns, Sa and Sb, after beat-up reed 5 moves to Filling Insertion 15 the fell of the fabric to ensure adequate space for the Selvage Needles insertion of latch needles 9 as described further below). Selvage Hold Rod Beat-Up As these motions are completed, filling needles 2 Filling Tension I withdraw to their original positions on each side of the Filling Tension II inverted T shape formed by the warp yarn layers so as Loop Forming Rods 20 Selvage Latch Needles to form fore end weft loops (see FIG. 7). O Selvage Tension Reed 5 is now linearly moved forwardly (carrying Harness 1 and 2 the weft insertion system therewith) toward the fell of 12 Harness 3 and 4 the fabric and filling tensioning devices 6 and 7 also 13 Take-Up begin to act so that the filling yarns (Y1 and Y2, respec 25 tively) are tensioned to keep the weft fore end loops The beginning position of the fabric formation cycle is tight. The timing of filling tensioning devices 6 and 7 shown in FIGS. 3-5 of the drawings. The three-dimen (associated with filling yarns Y1 and Y2, respectively) sional fabric to be formed can best be appreciated with and the duration of the tensioning period are dependent reference to FIG. 5 wherein the inverted T cross-sec on such variables as the fabric width, yarn type, and tional shape can be clearly seen as defined by five layers 30 other factors such as the air pressure of the two-way air of warp yarns X. Warp yarns X are most suitably drawn cylinders (not shown) which, preferably, are used to under tension from a creel (not shown) and between the pneumatically actuate all motions of the weaving pro heddles (not show) of harnesses 11a, 11b and 12a, 12b cess with the exception of the take-up motion which is (see FIGS. 3 and 4) and then through reed 5 in layers of preferably actuated by a suitable electric stepper motor warp yarn which are in horizontal and vertical align 35 and worm gear. Similar tensioning devices (not shown) ment. The cross section of three-dimensional fabric to are also used to apply tension to the selvage yarns, Sa, be woven as defined by warp yarns X can be divided Sb. Preferably, spring force is used to apply and main into two portions: 1) the horizontal bottom portion or tain a relatively low tension on the filling Y and selvage flange; and 2) the vertical raised portion or web of the Syarns. inverted T shape. The positioning of warp yarns X can clearly be seen in FIGS. 3-5. As beat-up reed 5 is linearly forced to the fell of the Two groups of filling yarns, Y1 and Y2, are used for fabric (see FIGS. 8 and 9), the yarns are packed into a weft or filling insertion with one weft group (Y1) being tight structure. Selvage loops are formed by rod 4 to inserted from one side for the flange and the other weft ensure that latch needles 9 are inserted between selvage yarn group (Y2) being inserted from the other side for needles 3 and selvage yarns Sa, Sb (see FIGS. 9 and 10). the web portion of the inverted T cross-shape (as best Two rods 8 are brought to pass by the selvage loops seen in FIG. 5). Two selvage yarns, Sa and Sb, are that are on latch needles 9 and which can hold the loops required to hold the fore end loops formed by the two formed on the needles during the previous cycle and different lengths of filling inserted by the two groups of further serve to help open the latches of needles 9 dur filling yarns, Y1 and Y2, respectively. Preferably, four 50 ing the latch needle motion (see FIGS. 8-10). harnesses, 11a, 11b, 12a, 12b, are used to control two After insertion of latch needles 9, rod 4 is pulled away sets of vertical Z yarns, Za-Zd. One set of Z yarns, Za, and the selvage falls onto latch needles 9 between the Zb, is inserted for the flange portion of the inverted T hook and latch. Selvage insertion needles 3 are then shape fabric, and the other set of Z yarns, Zc, Zd, is lowered and the selvage tensioning devices are actuated inserted for the web portion of the inverted T cross-sec 55 to apply tension on the so as to pull the sel tional shape fabric (see FIG. 5). Vertical yarns Z are vages tight. Rods 8 move away from latch needles 9, most suitably drawn under tension from the same creel and as latch needles 9 are withdrawing the loops formed (not shown) as warp yarns X and through harnesses by the last weaving cycle close the latch and slide off 11a, 1b, 12a, 12b and reed 5. the needles so as to form new loops. Harnesses 11a, 11b, With reference again to the computer timing diagram and 12a, 12b are then crossed so as to place the vertical of FIG. 1, a complete cycle of the weaving process will or Z yarns into the fabric and thus lock-in and form a now be described in sequence. As the computer control new series of weft picks with doubled filling yarns. program starts, the computer (not shown) sends a signal Finally, the take-up device (preferably an electric step to actuate solenoids (not shown) controlling double per motor and worm gear) moves the formed structure action air cylinders (not shown) which actuate filling 65 a distance equal to the repeating cycle length of the lock devices 1 and selvage lock devices (not shown). fabric formation, and reed 5 is moved back to its origi The lock devices are actuated, and then both the filling nal position with filling and selvage locking devices 1 yarns, Y1 and Y2, and selvage yarns, Sa and Sb, are being released. Most suitably, extra filling and Selvage 5,085,252 7 8 yarns are then withdrawn and stored in the associated It will be understood that various details of the inven tensioning devices, and locking devices 1 then lock the tion may be changed without departing from the scope yarns in place again so that the aforementioned cycle of the invention. Furthermore, the foregoing descrip may be again repeated in order to continuously produce tion is for the purpose of illustration only, and not for the three-dimensional fabric in accordance with the the claims. method of the invention. What is claimed is: Applicants wish to emphasize that the principles for 1. A method for weaving a three-dimensional fabric the formation of other shapes of fabric cross section are having a variable predetermined cross-sectional shape the same with necessary variations in the fabric forma comprising the steps of tion process being within the ability of one skilled in the a. providing a plurality of layers of warp yarns which art of three-dimensional fabric weaving and within the are in horizontal and vertical alignment and main contemplated scope of the instant invention. tained under tension, said layers of warp yarns Also, applicants wish to emphasize that although the defining a variable predetermined cross-sectional fabric formation process described above would utilize shape; only one pneumatic actuator on each side of the shape 15 b. selectively inserting a plurality of parallel weft defined by the layers of warp yarn to simultaneously yarns which are connected by a loop at the respec actuate the plurality of weft insertion needles 2 (see tive fore ends thereof into spaces between said FIG. 5), other techniques are possible and within the layers of warp yarn, said parallel weft yarns being scope of the invention including differential length weft inserted a predetermined and differential horizon insertion from only one side as well as alternative inser tal distance from at least one side of said warp yarn tion of weft yarns from first one side and then the other cross-sectional shape in accordance with the shape side during the weaving process. Also, it is possible that of the fabric being formed; two or more blocks of weft needles 2 may be indepen c. threading selvage yarn through the loops at the dently pneumatically actuated for uniform or differen fore ends of said weft yarns; tial length weft insertion from each side of the shape 25 d. bringing a reed into contact with the fell of the formed by the warp layers in order to form certain fabric being formed; complex cross-sectional fabric shapes for use as pre e. inserting vertical yarns into spaces between verti forms and the like. By way of example and not limita cal rows of said warp yarns in a direction substan tion, an I cross-sectional shape could utilize simulta tially perpendicular to both said warp and said neous weft insertion from both sides with a single block parallel weft yarns, said vertical yarns being selec of needles on one side serving to insert weft in the web tively threaded through a plurality of harnesses so of the I and two independent blocks of needles actuated as to be separated into a predetermined plurality of by two independent pneumatic actuators on the other vertically movable yarn systems by said harnesses side serving to insert weft yarn into the top and bottom in accordance with the shape of the fabric being flange of the I shaped profile formed by the layers of 35 formed, and said yarn systems being selectively warp yarn in the reed. Thus, weft insertion can be either vertically moved by said harnesses to insert said simultaneous from both sides or from alternating sides, vertical yarns into said fabric; and and the number of pneumatic actuators can vary on f, forming a three-dimensional fabric by repeating the each side from one to a plurality of actuators each serv steps (a)-(e) after insertion of said vertical yarns. ing to motivate a block of weft insertion needles. 40 2. A method according to claim 1 wherein an integral The commonality of the aforementioned variations is I shaped fabric is formed. that the method of the present invention provides for 3. A method according to claim 1 wherein an integral differential length weft insertion from one or both sides T shaped fabric is formed. of a three-dimensional fabric being formed in order to 4. A method according to claim 1 wherein said weft traverse the complex fabric profile defined by the hori 45 yarns are simultaneously inserted from both sides of said zontally and vertically aligned layers of warp yarn ex warp yarn cross-sectional shape. tending through the reed. Although applicants prefer 5. A method according to claim 1 wherein said weft the use of pneumatic actuators for all yarn formation yarns are alternately inserted from opposing sides of motions (other than fabric take-up) for the manufacture said warp yarn cross-sectional shape. of fabrics from materials such as carbon fibers, appli SO 6. A method according to claim 4 or 5 wherein said cants contemplate that other apparatus could also be weft yarns from one side of said warp yarn cross-sec utilized by one skilled in the art and familiar with the tional shape are inserted different horizontal distances novel fabric formation method of applicants' invention. than said weft yarns from the other side of said warp The yarn lock and tensioning devices as well as the yarn cross-sectional shape. selvage hold rod and loop forming rods described 55 7. A method according to claim 4 or 5 wherein the herein are a matter of design choice and may also be weft yarns from each side of said warp yarn cross-sec modified as desired in the practice of the method of the tional shape are inserted non-uniform horizontal dis invention. tances. Finally, applicants wish to note that many materials 8. A method according to claim 1 wherein said sel may be useful for weaving the variable cross-sectional vage yarn is threaded through the fore end loops of said shape three-dimensional fabric according to the present weft yarns by latch needles. invention. These materials include, but are not limited 9. A three-dimensional fabric made in accordance to, organic fibrous material such as cotton, linen, wool, with the method of claim 1. nylon, polyester, and polypropylene and the like and 10. A method for weaving a three-dimensional fabric other inorganic fibrous materials such as glass fibre, having a variable predetermined cross-sectional shape carbon fibre, metallic fiber, asbestos and the like. These comprising the steps of: representative fibrous materials may be used in either a providing a plurality of layers of warp yarns which filament or spun form. are in horizontal and vertical alignment and main 5,085,252 10 tained under tension, said layers of warp yarns a providing a plurality of layers of warp yarns which defining a variable predetermined cross-sectional are in horizontal and vertical alignment and main shape; tained under tension, said layers of warp yarns b. selectively inserting a plurality of weft yarns which defining a variable predetermined cross-sectional are connected by a loop at the respective fore ends shape; thereof into spaces between said layers of warp b. selectively inserting a plurality of weft yarns which yarn, said weft yarns being simultaneously inserted are connected by a loop at the respective fore ends a predetermined and differential horizontal dis thereof into spaces between said layers of warp tance from both sides of said warp yarn cross-sec yarn, said weft yarns being alternatively inserted a tional shape in accordance with the shape of the O predetermined and differential horizontal distance fabric being formed; from opposing sides of said warp yarn cross-sec c. threading selvage yarn through the loops at the tional shape in accordance with the shape of the fore ends of said weft yarns; fabric being formed, said weft yarns from one side d. bringing a reed into contact with the fell of the of said warp yarn cross-sectional shape being in fabric being formed; 15 serted different horizontal distances than weft e. inserting vertical yarns into spaces between verti yarns from the other side; cal rows of said warp yarns in a direction substan c. threading selvage yarn through the loops at the tially perpendicular to both said warp and weft fore ends of said weft yarns; yarns, said vertical yarns being selectively d. bringing a reed into contact with the feel of the threaded through a plurality of harnesses so as to 20 fabric being formed; be separated into a predetermined plurality of ver e. inserting vertical yarns into spaces between verti tically movable yarn systems by said harnesses in cal rows of said warp yarns in a direction substan accordance with the shape of the fabric being tially perpendicular to both said warp and weft formed, and said yarn systems being selectively yarns, said vertical yarns being selectively 25 threaded through a plurality of harnesses so as to vertically moved by said harnesses to insert said be separated into a predetermined plurality of ver vertical yarns into said fabric; and tically movable yarn systems by said harnesses in f. repeating the steps (a)-(e) after insertion of said accordance with the shape of the fabric being vertical yarns. formed, and said yarns systems being selectively 11. A method for weaving a three-dimensional fabric 30 vertically moved by said harnesses to insert said having a variable predetermined cross-sectional shape vertical yarns into said fabric; and comprising the steps of: f repeating the steps (a)-(e) after insertion of said a providing a plurality of layers of warp yarns which vertical yarns. are in horizontal and vertical alignment and main 13. A method for weaving a three-dimensional fabric tained under tension, said layers of warp yarns 35 having a variable predetermined cross-sectional shape defining a variable predetermined cross-sectional comprising the steps of: shape; a. providing a plurality of layers of warp yarns which b. selectively inserting a plurality of weft yarns which are in horizontal and vertical alignment and main are connected by a loop at the respective fore ends tained under tension, said layers of warp yarns thereof into spaces between said layers of warp defining a variable predetermined cross-sectional yarn, said weft yarns being simultaneously inserted shape; a predetermined and differential horizontal dis b. selectively inserting a plurality of weft yarns which tance from both sides of said warp yarn cross-sec are connected by a loop at the respective fore ends tional shape in accordance with the shape of the thereof into spaces between said layers of warp fabric being formed, said weft yarns from one side 45 yarn, said weft yarns being simultaneously inserted of said warp yarn cross-sectional shape being in a predetermined and differential horizontal dis serted different horizontal distances than weft tance from both sides of said warp yarn cross-sec yarns from the other side; tional shape in accordance with the shape of the c. threading selvage yarn through the loops at the fabric being formed, said weft yarns from each side fore ends of said weft yarns; SO of said warp yarn cross-sectional shape being in d, bringing a reed into contact with the feel of the serted non-uniform horizontal distances; fabric being formed; c. threading selvage yarn through the loops at the e, inserting vertical yarns into spaces between verti fore ends of said weft yarns; cal rows of said warp yarns in a direction substan d. bringing a reed into contact with the fell of the tially perpendicular to both said warp and weft 55 fabric being formed; yarns, said vertical yarns being selectively e. inserting vertical yarns into spaces between verti threaded through a plurality of harnesses so as to cal rows of said warp yarns in a direction substan be separated into a predetermined plurality of ver tially perpendicular to both said warp and weft tically movable yarn systems by said harnesses in yarns, said vertical yarns being selectively accordance with the shape of the fabric being threaded through a plurality of harnesses so as to formed, and said yarn systems being selectively be separated into a predetermined plurality of ver vertically moved by said harnesses to insert said tically movable yarn systems by said harnesses in vertical yarns into said fabric; and accordance with the shape of the fabric being f, repeating the steps (a)-(e) after insertion of said formed, and said yarn systems being selectively vertical yarns. vertically moved by said harnesses to insert said 12. A method for wearing a three-dimensional fabric vertical yarns into said fabric; and having a variable predetermined cross-sectional shape f repeating the steps (a)-(e) after insertion of said comprising the steps of vertical yarns. 5,085,252 11 12 14. A method for weaving a three-dimensional fabric c. threading selvage yarn through the loops at the having a variable predetermined cross-sectional shape fore ends of said weft yarns; comprising the steps of: d. bringing a reed into contact with the fell of the a providing a plurality of layers of warp yarns which fabric being formed; are in horizontal and vertical alignment and main- 5 e. inserting vertical yarns into spaces between verti tained under tension, said layers of warp yarns cal rows of said warp yarns in a direction substan defining a variable predetermined cross-sectional tially perpendicular to both said warp and weft shape; yarns, said vertical yarns being selectively b. selectively inserting a plurality of weft yarns which threaded through a plurality of harnesses so as to are connected by a loop at the respective fore ends 10 be separated into a predetermined plurality of ver thereof into spaces between said layers of warp tically movable yarn systems by said harnesses in yarn, said weft yarns being alternately inserted a accordance with the shape of the fabric being predetermined and differential horizontal distance formed, and said yarn systems being selectively from opposing sides of said warp yarn cross-sec- vertically moved by said harnesses to insert said tional shape in accordance with the shape of the 15 vertical yarns into said fabric; and fabric being formed, said weft yarns from each side f. repeating the steps (a)-(e) after insertion of said of said warp yarn cross-sectional shape being in- vertical yarns. serted non-uniform horizontal distances;

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