Patent Publication Number: US-6991690-B2

Title: Composite camouflage construction and method for manufacturing composite camouflage construction

Description:
This application is a Divisional of U.S. application Ser. No. 10/365,252, filed Feb. 12, 2003 which issued as U.S. Pat. No. 6,787,212. 

   BACKGROUND OF THE INVENTION 
   Camouflaged materials are used to conceal objects, personnel, and equipment in natural terrain. Camouflaged materials may be provided in the form of drapable sheets or net structures of varying shapes and sizes. Camouflaged materials in some instances may be a solid color. In other applications, such materials may be dyed or printed in multiple patterns to simulate the coloration or texture of the terrain in which the camouflage is utilized. Typical examples of colors that may be employed include various patterns of black, brown, and green. 
   The disclosure of U.S. Pat. No. 5,486,385 describes a composite product including an open mesh net substrate which is bonded to a sheet material such as a woven fabric, non-woven fabric, knit fabric, or the like. The sheet is colored in a desired camouflage pattern, bonded to the substrate along spaced lines of attachment, and cut to simulate the appearance of natural objects of the terrain. Separate lobes are formed in the sheet to simulate the appearance of natural objects in the terrain, such as leaves or foliage. Then, the lobes are heated as much as 400 degrees Fahrenheit to wrinkle and deluster the camouflage lobes. 
   To improve the camouflage characteristics of such composites, it is desirable to introduce three-dimensional effects to the materials. That is, wrinkling or gathering of the materials is desirable, and results in a visual effect that more closely simulates natural terrain. Methods and products that result in a more highly wrinkled and a greater three-dimensional effect upon the structure are desirable. 
   Robinson Laboratories, Inc. of 110 North Park Drive, Cannon Falls, Minn. 55009 distributes commercially a camouflaged product designated “3D REAL LEAF”™. This product is said to provide a layered composition having a first backing layer and a second leafy layer that is stitched to the backing layer. It is believed that a differential feed rate is employed in the construction of this product to provide a bunching of material along stitched seams. 
   The durability and tightness of the stitching in camouflage composite constructions is an important factor in the overall effectiveness of the camouflage composite. Camouflaged materials typically are used outdoors in rugged environments. Therefore, a construction that is physically strong, durable, and provides maximum three-dimensional effect is highly desirable. The durability of the three-dimensional effect depends upon the stitch or thread maintaining its position relative to other layers of the construction. A stitched seam of thread preferably should provide a high degree of structural integrity to maintain its physical form during use, thereby providing maximum three-dimensional effects to the composite fabric construction. It is therefore desirable to provide a thread for stitching that will exhibit superior strength and resist elongation of the composite construction along the seam. A thread for stitching that is adapted to maintain or enhance three-dimensional gathering effects along a seam also is desirable. A seam that will show a high degree of resistance to breakage when opposed fabric layers are subjected to a separating force also would be desirable. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A full and enabling disclosure of this invention, including the best mode shown to one of ordinary skill in the art, is set forth in this specification. The following Figures illustrate the invention: 
       FIG. 1  shows a plan view of a first embodiment of the composite construction of the invention which employs a net mesh backing material as a first textile substrate in the camouflage construction, the construction including spaced parallel seams running vertically in the machine direction of the construction; 
       FIG. 2  shows an end view of the camouflage construction seen in  FIG. 1 ; 
       FIG. 3  depicts a second embodiment of the invention which employs a solid first textile substrate backing material, also containing vertically oriented parallel seams; 
       FIG. 4  shows an end view of the camouflage construction seen in  FIG. 3 ; 
       FIG. 5  is a side elevation view depicting schematically some of the principal components of the apparatus for producing the camouflage construction of the invention; 
       FIG. 6  is an enlarged side sectional elevation view of the cutting head of the cutting station of the apparatus of  FIG. 5 ; 
       FIG. 7  is a front elevation view of a portion of the cutting head station of the apparatus of  FIGS. 5 and 6 , looking generally in the direction of arrows  7 — 7  of  FIG. 6 ; and 
       FIG. 8  is a top plan view of a portion of the cutting head of the cutting station of the apparatus of  FIG. 5  taken generally along line  8 — 8  of  FIG. 6 , and looking in the direction of the arrows; 
       FIG. 9  illustrates properties of one preferred thread that may be used in the present invention, in which shrinkage % versus draw ratio of this particular cold drawn thread is presented; 
       FIG. 10  shows breaking elongation of the thread presented in  FIG. 9 ; 
       FIG. 11  illustrates breaking strength of the thread previously presented in relation to  FIGS. 10–11 ; and 
       FIG. 12  graphically depicts breaking tenacity versus draw ratio for the same cold drawn thread of  FIGS. 9–11 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference now will be made to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not as a limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in this invention without departing from the scope or spirit of the invention. 
   Surprisingly, it has been discovered that by modifying certain commercially available yarn, a new high-shrink material may be formed which shrinks upon application of heat. This material may be used as a yarn, or as a thread. In the application of the invention, it has been found that use as a thread is very useful, to connect two or more textile substrates, as further described herein. Such a thread may be employed in a stitch to connect a number of textile substrates, thereby forming a connected composite textile construction. Upon the application of heat to the composite construction with shrinkable thread, a shrink-hardened seam may be formed along the stitch. Shinkage amounts of such thread may be as much as 70% of the actual thread length, as further described below. The number of stitches per linear inch in the composite construction upon heating may increase as well (due to thread shrinkage, primarily), by as much as 10–20%. 
   Conventional textile and sewing applications employ a thread or yarn which exhibits very little shrinkage after it is applied in a stitch. That is, shrinkage of thread typically is intentionally avoided in the manufacture of textile articles. 
   However, in the application of the invention, a high degree of shrinkage is desirable to form a shrink-hardened seam connecting at least two textile substates. Upon forming a layered composite by stitching with the high-shrink thread, and subsequently heating the composite construction, the thread length decreases and therefore tightens against the joined substrate layers, which serves to maximize the amount of bunching or gathering of such mated textile substrates. 
   A maximum amount of bunching or gathering increases the visual three-dimensional effect of the fabric. Thus, high shrink thread may be employed to achieve a shrink-hardened seam in camouflage fabrics to maximize the visual performance of such fabrics. 
   For purposes of this specification, materials used for stitching two separate pieces of textile to each other shall be referred to herein as “thread” and not “yarn”. However, the invention may be applied in the use of such high shrink materials in “yarn” applications as well as in thread applications. In general, for purposes of this description, a yarn is described as a textile useful for manufacture of a sheeted material, while a thread is used as a connecting mechanism for one or more sheeted materials. Furthermore, the use of the “textile” shall not be limited to sheet or woven materials, and may include as well flexible films, such as for example, urethane films and the like. 
   In one application of the invention, it is possible to provide a multi-layered camouflage construction having three-dimensional qualities with reduced luster and increased gathering or wrinkling. The camouflage construction may closely approximate the visual appearance of terrain. The construction may comprise two substrates mated to each other and stitched along their length using high-shrink thread. The thread subsequently may be heated to bunch or gather the fabric along the stitched seam, thereby forming a shrink-hardened seam. Thus, a gathered three-dimensional appearance may be formed in either or both of the first or second substrate, depending upon the particular application, and the amount of gathering necessary in the particular composite being manufactured. 
   This bunching or gathering effect also may be achieved in two directions which are perpendicular to each other (i.e. cross and machine direction) upon the substrate, using techniques further described below. Furthermore, in the application of the invention it is not necessary or desirable to use different running speeds of the first substrate relative to the second substrate to achieve gathering or bunching in the final composite construction. 
   A first textile substrate, also known as a “base” fabric, may be stitched to a second textile substrate. The second textile substrate may comprise leaf-shaped nodes as further described below. The so-called base fabric may be heatset fabric, or non-heatset fabric, depending upon whether or not it is desired to shrink the base fabric further using heat once the composite is manufactured. That is, the base fabric itself also may be made to shrink, and this effect is especially pronounced in the applications which use non-heatset base fabric. Shrinkage of thread along a seam is desired, in many applications. Other applications of the invention, however, may employ elastic or elastic-containing materials to achieving bunching or gathering along a seam, including for example materials such as LYCRA™ (believed to be a trademark of the DuPont Company of Wilmington, Del.). 
   The second textile substrate from which nodes or leaf-shaped material is to be cut can be dyed, printed, or greige fabric. A lightweight 100% polyester woven fabric is believed to be very advantageous, but other fabrics and fibers may be employed as well, including poly/cotton blends, knits, non-wovens, and the like. 
   The thread employed to stitch together and form a shrink-hardened seam connecting the above referenced two textile substrate layers may be selected from many different thread types. One particularly advantageous thread type is a high shrink solution dyed polyester thread. 
   In one preferred application, the thread is applied in a chain stitch at a rate of about 5 to about 20 stitches per inch, most preferably about 10 stitches per inch. The size or denier of the thread plays an important role in the practice of the invention. A greater thread size used in a composite is believed to provide an enhanced gathering strength within the composite. Therefore, thread shrinking is directly related to the amount of bunching or gathering of material that may be achieved along a seam. Thus, thread size may affect the overall three-dimensional textile appearance and performance of a camouflage composite construction. 
   Referring to the drawings,  FIG. 1  shows a first embodiment of the invention which comprises a multi-layered camouflage construction  21 . The camouflage construction  21  is comprised of a first textile substrate  22  and a second textile substrate  23  which overlays the first textile substrate  22 . The first textile substrate  22  comprises a first end  30  and a second opposite end  31 . In this particular embodiment, the first textile substrate  22  is of an open mesh type, as seen in  FIG. 1 . The second textile substrate  23  provides a plurality of transversely orientated lobes  24  which are aligned along first line of attachment  25 , second line of attachment  26 , third line of attachment  27 , and fourth line of attachment  28 , as examples.  FIG. 1  shows only a partial view of the entire fabric that could be manufactured, and the number of separate lines of attachment which could be used will vary depending on the particular application. Each lobe  24  includes a base portion  33  which is connected to a line of attachment  25 , and an outer wrinkled in portion  34  which is directed towards an opposite line of attachment. In this way, the lobes are oriented towards each other, and in alternating sequence, so they substantially cover, but do not completely cover, the first textile substrate  22 . 
     FIG. 1  illustrates the bunching or gathering of the first textile substrate  22  and the second textile substrate  23  which may be effected in several ways, at least one of which is described herein. The bunching or gathering of the first textile substrate  22  provides advantageous three-dimensional visual characteristics that contributes to the effectiveness of the camouflage construction  21  in sumulating terrain. In the particular embodiment of  FIG. 1 , the bunching or gathering of the first textile substrate  22  is provided along the length of the first thread  35  along the first line of attachment  25  into a shrink-hardened seam  29   a , and by a second thread  36  along the second line of attachment  26 , which runs along shrink-hardened seam  29   b . Further, a third thread  37  is provided along the third line attachment  27  to form shrink-hardened seam  29   c , and the fourth thread  38  along the fourth line of attachment  28  forms a shrink-hardened seam  29   d.    
     FIG. 2  illustrates an end view of the first embodiment of the invention previously seen in  FIG. 1 . In  FIG. 2 , the multi-layered camouflage construction  21  is a multi-layered composite. The first textile substrate  22  is seen underneath, while the first thread  35 , second thread  36 , third thread  37 , and fourth thread  38  are shown in cross section at the point at which they attach the first textile substrate  22  to the second textile substrate  23 . This attachment occurs at the lines of attachment  25 – 28 , respectively. Furthermore, the second textile substrate  23  is seen projecting upwards to provide a three-dimensional effect upon the overall camouflage construction  21 . The shrink-hardened seams  29   a–d  are seen in cross-section in the  FIG. 2 . 
     FIG. 3  illustrates a second embodiment of the invention in which a multi-layered camouflage construction  50  is comprised of a first textile substrate  51  (with first end  62  and second end  63 ) that is solid in form (as opposed the mesh net configurations of  FIG. 1–2 ), and a second textile substrate  52 . In the particular example of  FIG. 3 , the first textile substrate comprises a solid poly-cotton material, but other solid sheets of material can also be used, as further described herein. A plurality of lobes are provided, including for example lobe  54  having a base portion  55  connected to third line of attachment  60 , and a outer wrinkled end portion  56  which projects above the first textile substrate  51 . 
   From left to right as seen in  FIG. 3 , a first line of attachment  58 , a second line of attachment  59 , a third line of attachment  60 , and a fourth line of attachment  61  extend parallel to each other from the first end  62  of the first textile substrate  51  to the second end  63  of the first textile substrate  51 . Furthermore, the lines of attachment are formed by first thread  65  (which forms shrink-hardened seam  49   a ), second thread  66  (which forms shrink-hardened seam  49   b ), third thread  67  (which forms shrink-hardened seam  49   c ), and fourth thread  68  (which forms shrink-hardened seam  49   d ), respectively. 
     FIG. 4  illustrates an end view of the second embodiment of the invention of  FIG. 3 , showing the above recited features in end view. 
     FIGS. 5–8  illustrate manufacturing procedures employed to produce the multi-layered composite construction of the invention. U.S. Pat. Nos. 5,486,385; 5,281,451; 5,013,375; 5,476,561; and 4,931,320; each relate to constructions and methods of making various embodiments of camouflage construction materials. Reference is therefore made to these granted patents for general information regarding the manufacture of such articles. 
   Delustering of camouflage net resulting in low degree of reflection makes the composite camouflage construction difficult to observe, and is therefore desirable. Furthermore, the melting and wrinkling of camouflage lobes results in greater air movement being possible through the net, with reference to the embodiment of  FIGS. 1–2 . This is particularly useful in applications of the construction as a drape or covering over large pieces of equipment, in which wind or air resistance may become a significant factor due to the large surface area exposed to wind. In clothing applications, air movement may contribute to comfort for the wearer. One additional means of wrinkling and delustering camouflage lobes is the application of heated pressurized gas streams to the camouflage. 
   Method and apparatus for producing the lightweight camouflage fabric in accordance with the present invention may be described by reference to  FIGS. 5–8 . In  FIGS. 5–8 , the multi-layered camouflage construction of  FIGS. 1–2  is shown, by way of example. As seen in schematic side elevation view in  FIG. 5 , an indefinite length continuous sheet of material, such as a second textile substrate  23 , and an indefinite length web of the first textile substrate  22  (such as a knitted mesh fabric in this instance) are directed from supply rolls  124 ,  126  respectively by suitable guide means, such as rollers or bars  128 . The substrates  22 ,  23  are provided in contiguous facing relation along the desired path of travel, as shown by the arrows in  FIG. 5 . 
   Spaced in the path of travel are bonding means, such as a sewing station  130  containing a plurality of individual sewing heads  131  spaced across the cross direction of the process or pathway. The second textile substrate  23  is stitched to the first textile substrate  22  along first, second, third and fourth lines of attachment  25 – 28  (see  FIGS. 1–2 ). 
   Typically, the sewing means used is a Malimo RTM stitch-bonding machine, which is known in the industry. However, other machines could be employed, including for example straight-line quilting machines. Stitch-bonding of the sheet or second textile substrate  23  and first textile substrate  22  along plural lines of attachment during movement of the multi-layered camouflage construction  21  through the bonding means produces a plurality of continuous open-ended channels  132   a–f  ( FIG. 8 ) in the composite bonded structure. Any number of stitches per inch may be employed, but it has been found that stitches applied at a rate of bout 5–20 stitches per inch are advantageous. Furthermore the width of such open-ended channels  132   a–f  may be between about 1–10 inches, preferably about 2–3 inches. One very useful embodiment employs channels  132   a–f  having a width of about 3 and one-eighth inches. 
   Positioned in the path of travel of the composite bonded sheet and substrate after the sewing station  130  are multiple cutting means, located at a cutting station  134 . As seen in  FIGS. 5–8 , cutting station  134  includes a plurality of generally U-shaped guides  136  mounted in spaced relation across the path of travel of the textile substrates  22 , 23  on cross member  137  of support frame  138 . As the composite web moves in its longitudinal path of travel (see direction arrows in  FIGS. 5 and 6 ), the guides  136  pass into each of the respective channels  132   a–f  (see  FIG. 8 ) formed between adjacent lines of attachment  25 – 28  of the first and second textile substrates  22 , 23 . Each U-shaped guide  136  is of sufficient thickness and height ( FIG. 6 ) to separate and space the face of the second textile substrate  23  at a distance from the face of the first textile substrate  22 . 
   Cutting means are mounted for reciprocating movement and positioned transverse to the path of travel of the substrates  22 , 23 , shown as a plurality of electrically heated wires  140 , each of which is mounted on cutters  142  of an insulator bar  144 . Insulator bar  144  is attached by elevator mechanisms  145   a–c  to cross beam  146  on the support frame  38 . The beam  146  is mounted on rods  147  for transverse reciprocation on frame  138 , across the path (in the cross direction) of web travel. Beam  146  is, therefore, reciprocated by suitable drive means, such as for example pneumatically controlled programmed piston motor  148  (see  FIG. 7 ). 
   As best seen in  FIGS. 6 and 7 , each heated wire  140  extends downwardly to reside and reciprocate within the confines of each U-shaped guide member  136 , moving very quickly to provide a movement that approximates the outline or exterior shape desired for construction of each lobe  24 . Electrical energy is supplied from a suitable supply source to heat the wires  140  to a desired temperature to cut the continuous sheet fabric (or second textile substrate  23 ) without contacting or adversely affecting the supporting first textile substrate  22 , which also is attached. 
   Cross beam  146  is reciprocated by a suitable drive means, such as motor  148  that is coupled to a ball screw  165  by means of a coupler  173 . The ball screw  165  is rotatably attached to support frame  138  by means of a dual attachment members  167 . The ball screw nut  174  is fixed to cross beam  46 . As best seen in  FIGS. 6 and 7 , each electrically heated air cutter  142  extends downwardly to reside and reciprocate slightly above each U-shaped guide member  136 . Electrical energy is supplied from a suitable supply source to electrical wire  162  to heat the inside of air cutter  142  to the desired temperature. In other applications (not shown in the Figures), a laser cutter could be employed. Furthermore, air is supplied from a suitable supply source to air conduit  163 , which injects the air into the air cutter  142  to thereby cut by means of an air stream the continuous woven fabric  23  without cutting the supporting knitted mesh fabric  22 , which is attached. 
   Operation of the motor  148  driving the ball screw  165  thus reciprocates the cross beam  146  holding each of the electrically heated air cutters  142  to move transversely back and forth slightly above each of their U-shaped guides  136  as the woven fabric  23  and knitted mesh fabric  22  move through the cutting station  134 . The electrically heated air cutters  142  cut the woven fabric  23 , between the adjacent lines of attachment  25 – 28 , into a plurality of lobes  24 , thus opening each of the channels  132   a–f  formed in the woven fabric  23  and knitted mesh fabric  22  as the multi-layered camouflage construction  21  passes through cutting station  134 . 
   The shape and configuration of lobes  24  prior to heating may be varied, as desired, depending on the speed of movement through the cutting station  134  and the speed of reciprocation of the electrically heated air cutters  142 . The speed of movement of the electrically heated air cutters  142  may be adjusted by adjustment of the servo motor speed. Various programming means well known in the art may be employed to provide varying and various patterns of lobes  24 , as desired. Operation of the cutting station may be computer-controlled, but this is not required. Other embodiments may employ other means for cutting lobes, in which there is no cross beam  146 , but instead each U-shaped cutting guide member  136  is configured for independent movement, thereby providing an opportunity for randomly cut leaf patterns along the composite. However, it should be recognized that other embodiments not specifically shown could employ techniques of cutting lobes or leaf-shaped portions in the second textile substrate prior to joining the second textile substrate to the first textile substrate, and therefore the invention is not limited to only those cutting and assembly methods and apparatus shown herein. 
   As shown in one desirable embodiment, electrically heated air cutters  142  are operated to provide a lobe configuration resembling a simulated leaf shape. The camouflage construction  21  may be suitably dyed or printed in a desired camouflage configuration of random coloration. The woven fabric  20  and knitted mesh fabric  22  preferably each may be dyed or printed prior to bonding to each other, and subsequent cutting. 
   Typically, the knitted mesh fabric  22  forming the net substrate which supports the second (woven) textile substrate  23  in the form of a continuous sheet may be dyed black, or a neutral background shade. It may be formed of essentially common textile material, including knit, polyester, or the like. The continuous sheet or second textile substrate  23  may be patterned in random green, brown, black coloration to conform to terrain in which the camouflage construction is employed. As mentioned, the particular mesh size of the net support substrate may be varied, but preferably it is sufficiently small size as to not snag on objects or equipment to be concealed. Similarly the distance between the lines of attachment of the sheet to the substrate may vary, depending upon the length and the size of the lobe desired for simulation of leaves or foliage, but about 2–6 inches has been found to work well, with about three and one-eighth inches being preferred. 
   The camouflage construction  21  leaving the cutting station  34  (see  FIG. 5 ) is passed through guide rolls  151  and  152  and is directed downwardly to a creasing roll  154 . This allows the lobes  24  to fall freely away from the mesh backing prior to passage through the heater  156 . 
   Importantly, heater  156  applies energy to the underside of the multi-layered camouflage construction. The heater operates preferably in the range of 200–400 degrees. Fahrenheit. In the heater  156  the lobes tend to shrink while they curl away from the mesh  12 , serving to increase the three-dimensional effect. 
   One important function of heating the underside or backside  53  of the multi-layered construction is that the threads  35 – 38  forming the lines of attachment  25 – 29  shrink substantially, thereby forming what is referred to herein as shrink-hardened seams  29   a–d . The threads are particularly susceptible to infared radiation which is incident on the outer thread surface, as shown in  FIG. 5 . However, other heat sources which are not infared also could be employed in the invention. It is preferred that the processing speed be adjusted so that a particular thread portion may spend about 5 seconds at heater temperatures of between 250–400 degrees F. to faciliate full shrinkage effects. The exact temperature that is ideal in any given application will depend upon the materials used, the thread used, the denier of the thread, whether or not the thread is a multi-ply thread, and the like. Thread shrinkage amounts for one particularly useful thread is shown and discussed herein with respect to  FIGS. 9–12 , including both a technical description and a summary of testing of such thread. 
   The fabric  50  passes around the creasing roll  54  (see  FIG. 5 ) with the curved lobes facing the roll so that crease lines  58  are formed in the lobes to produce the fabric  21  shown in  FIG. 1 . As can be seen in  FIG. 1  the crease lines  58  are random so that the exposed portions of the lobes  24  are random. Furthermore, heating of the threads  35 ,  36 ,  37 , and  38  along respective lines of attachment  25 – 28  results in formation of shrink-hardened seams  29   a–d.    
   The multi-layered camouflage construction  21  may be suitable dyed or printed in a desired camouflage configuration of random coloration. The sheet or second textile substrate  23  and the first textile substrate  22  may be dyed or printed prior to bonding and cutting. Typically, the net substrate (first textile substrate  22 ) which supports the continuous sheet is dyed or printed black, partially black, while, tan, green, or a neutral background shade, depending upon is the terrain to be simulated. The second textile substrate  23  may be patterned in random green, brown, and black coloration to conform to terrain in which the camouflage construction is employed. 
   The particular mesh size of the first textile substrate or net support backing  22  may be varied, but preferably it is sufficiently small in mesh size as to not snag on objects or equipment which is intended to be concealed. Similarly, the distance between the stitch lines of attachment of the sheet to the substrate may vary, depending upon the length and the size of the lobes desired for simulation of leaves or foliage in the terrain to be simulated. The net support backing  22  may be comprised of many different type of materials, including polyester, nylon, polypropylene, films, polyester copolymers, olefins, polyethylene, and other polymeric materials. 
   A textile substrate may be provided in an overfeed condition due to shinkage of the composite construction  21  in the machine direction as heating progresses. A feeding rate of about 6.9 yards per minute may be employed after the stitching is accomplished, at the point in  FIG. 5  wherein the composite passes roll  151  and roll  152 , and moves towards the above referenced heater  156 . The web output beyond the heater (past the ironing roll  154 ) is typically at a rate of about 5.7 yards per minute. 
   Thus, the overall rate at which ironing roll  154  turns is about 17.4% faster than the rotation of roll  152  to accommodate for shrinkage in the machine direction that is observed when employing a high shrink thread as recited herein. This variation in web processing speed may be referred to as an overfeed. 
   Cold Drawn Thread Preparation 
   In the application of the invention, thread employed in sewing station  130  to produce camouflage construction  21  may be of many different types, and is not limited to any particular thread cited herein. Furthermore, some applications of the invention may use a single ply yarn, while other applications may use a two, three, four or more ply yarn as a base or starting material for thread construction. Yarn materials manufactured and distributed by Kosa, DuPont, Nanya (division of Formosa Plastics in Taiwan) and others could be employed in the practice of the invention. However, one particularly useful yarn which may be used in this application is purchased and then processed as further described below, prior to use. Materials including nylon, polyester, polypropylene, and others may be employed to construct a high strength thread capable of shrinking upon addition of heat, for application in the invention. 
   Two plies of Omara partially oriented polyester yarn (270 denier; 34 filament) may be employed and then modified in the practice of the invention. The Omara yarn employed for the particular examples as discussed herein is a solution dyed partially oriented (POY) polyester material, and it may be purchased from the manufacturer Omara Corporation. 
   The yarn, after purchase, is modified by cold drawning at ambient temperature at a speed of about 400 meters/minute. Two plies of about 150 denier are intertangled to provide a thread for stitching. The thread is applied in sewing station  130 . The stitch applied may be regular, irregular, continuous, or discontinuous. In some applications of the invention, no twist is provided in the thread, while in other applications twist is applied. In a preferred embodiment of the invention, a twist of less than about 1 turn per inch is applied, however, the invention is not limited to any particular amount of twist, or the presence of absence of twist in the thread. The thread then is capable of substantial shrinkage when subsequently exposed to heat, due to having been drawn cold. The substantial shrinkage upon application of heat generates the hardened seam of the invention, which has shown to be particularly useful in this application. 
   The hardened seams which result from the use of such cold drawn thread in the application of the composite construction is referred to herein as a “shrink-hardened” or “shrunk-hardened” seam, regardless of the specific type, size, or manufacturer that supplies the specific thread that is employed to manufacture such a hardened seam. In general, for purposes of this description, a “shrink-hardened seam” or “hardened seam” shall refer to any seam of thread in which the seam is stitched to connect two or more substrates, and then the thread is heated or otherwise energized to shrink the thread in place upon the substrates, resulting in a thread that is in tensioning relation to a substrate. Further, such a hardened seam causes the substate or fabric to which it is attached to become gathered or bunched along the seam. A shrink-hardened seam has been found to be particularly hardened and durable in such camouflage constructions, such a strong seam being configured for long life and low maintenance. 
   Testing of Cold Drawn Thread 
   Various testing was conducted for samples of cold drawn Omara thread as above described.  FIG. 9  shows a shrinkage test to determine total shrinkage of the Omara cold drawn thread, and was accomplished according to ASTM 4031. 
   In general, the results of shrinkage testing of the Omara cold drawn thread indicate that thread run with a draw ratio of between about 1.3 and 1.6 exhibits the greatest degree of shrinkage (as much as 70% as shown in  FIG. 9 ) and is thus the most desirable thread for this particular high-shrink application. Thus, a hardened seam may be produced with a maximum amount of bunching or gathering by use of such thread having such a draw ratio, for maximum three-dimensional effect. 
   Breaking elongation percentage results are reported in  FIG. 10 . Breaking strength results are reported in  FIG. 11 , and breaking tenacity is shown in  FIG. 12 . 
   Thread having an overall draw ratio of about 1.6 was employed in the construction which is shown in  FIGS. 1–2 ,  FIGS. 3–4 , and in the Samples A, B, and C below, as further described. 
   Samples 
   Product Samples were prepared for testing on the following multi-layered composite textile constructions. Each of the embodiments shown below as Sample A, B, and C differ from each other only with regard to the first textile substrate, or “backing” layer that is employed with each, as described. 
   Product Sample “A” Heat Set Mesh Construction 
   A multi-layered manufactured composite camouflage construction was prepared as described above in connection with the invention, and shown as well in  FIGS. 1–2 . This product includes a first textile substrate (backing layer) of non-heat set printed Rachel knit which may be obtained from Royal Carolina. 
   The thread used along the multiple lines of attachment, or stitches, consisted of two-ply, high shrink Omara brand yarn which had been modified as described above. Thread having an overall draw ratio of about 1.6 was used. 
   The thread was applied as 2/150 denier that was inserted using two ends per needle, at a rate of about 10 stitches per inch. 
   The thread was inserted by stitching as described above in connection with  FIGS. 5–9 , and then shrink-hardened by heating as set forth above. The heater temperature at the heater was about 1100 degrees F., which resulted in a temperature on the fabric (and on the thread) of about 300–400 degrees F. After heating, the stitch count increased to about 11 stitches per seam inch, due to thread shrinkage, and hardening of the seam. 
   A single ply of the thread, when removed from the shrink-hardened seam of the multi-layered construction was found to be about 418 denier. 
   Product Sample “B” Non-Heat Set Mesh Construction 
   A multi-layered manufactured composite camouflage construction as described above in connection with the invention. This product includes a first textile substrate (backing layer) of non-heat set printed Rachel knit (“Royal Carolina”). The fabric is printed and then heat set at 65 inches width prior to mating with a second textile substrate. 
   Thread was used along the multiple lines of attachment, or stitches. The thread was two-ply Omara brand yarn which had been cold drawn modified as described above. Thread having a draw ratio of about 1.6 was applied at 10 stitches per inch. The thread was applied as 2/150 denier that was inserted using two ends per needle. 
   Upon heating to the same temperatures as described above in connection with Sample A, the thread formed a shrink-hardened seam having about 11 stitches per linear inch of seam. 
   A single ply thread, when removed from the multi-layered construction after final heating, was found to be about 421 denier. 
   Product Sample “C” Integral or Solid Base Fabric Construction 
   A multi-layered manufactured composite camouflage construction as described above in connection with the invention, and shown as well in connection with  FIGS. 3–4  was constructed. The first textile substrate, or “base” fabric that is employed is a solid (not mesh) dyed polyester/cotton woven fabric. 
   The thread was used along the multiple lines of attachment, or stitches. The thread was Omara brand yarn described above. Heating was as previously described in connection with Samples A and B. The thread was applied as 2/150 denier and inserted using two ends per needle, resulting in 11 stitches per inch in the final product. A single ply of the thread, when removed from the multi-layered construction after final heating, was found to be about 417 denier. 
   Sample “D”—Commercial Product Manufactured by Robinson Laboratories 
   Robinson Laboratories, Inc. of 110 North Park Drive, Cannon Falls, Minn. 55009 distributes commercially a camouflaged clothing product designated “3D REAL LEAF”™. A men&#39;s large (L) garment was tested. 
   Testing Procedure 
   Tensile Test (Grab): In executing the tensile test of specimens A, B, C and D, specimens were cut from the multi-layered camouflage construction into test strips along the stitched seam (in the machine direction). The seam was in the center of each cut specimen, and the specimen size was about 8 inches long (along the seam) in the machine direction, and 3 inches wide in the cross direction. Specimens were gripped by opposing clamps, and force was applied along the longitudinal length of the seam until breakage of the specimens. The test determined the force required to break the seam in the machine direction, and thus measures the relative strength of the construction along the stitched seam. Results are reported in Table 1. 
   Tensile Test of Thread: Tensile testing was conducted on thread removed from the stitches of manufactured samples A, B, C, and D. The thread was therefore de-stitched from the manufactured products, and then placed in the test apparatus to determine the force required to break the thread alone. Results are shown in Table 2. 
   Seam Failure: This test determines the maximum sewn seam strength which can be achieved when a force is applied perpendicular to the seam. Seam breakage at the stitch line is measured by taking each of the product samples A, B, C, and D and securing the outer leafy lobe (second textile substrate) to one test fixture, and the base fabric (first textile substrate) to a second test fixture. Then, force is applied in the cross-direction (perpendicular to the seam) by the fixtures until failure of the seam. Results are shown in Table 3. 
   
     
       
         
             
           
             
               TABLE 1 
             
           
          
             
                 
             
             
               Tensile Test (Grab) of Sample Portions of Camouflage 
             
             
               Construction Along Stitched Seam 
             
          
         
         
             
             
             
             
          
             
                 
               Force Required 
                 
                 
             
             
                 
               to Break- 
               Percent 
               Percent 
             
             
                 
               Peak Load  
               Elongation at 
               Elongation at 10 
             
             
               Sample 
               Mean (lbf) 
               Peak Load (%) 
               Lbs (%) 
             
             
                 
             
          
         
         
             
             
             
             
          
             
               A 
               110.312 
               44.736 
               14.286 
             
             
               B 
               90.960 
               46.737 
               14.410 
             
             
               C 
               84.342 
               25.016 
               6.890 
             
             
               D 
               92.037 
               71.252 
               23.517 
             
             
                 
             
             
               Test Method ASTM D5034 
             
             
               Grip Separation 3.000 in. 
             
             
               Test Speed 12.000 in/min. 
             
             
               Five specimens per sample were averaged to obtain mean values set forth above. 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 2 
             
           
          
             
                 
             
             
               Tensile Results of Thread Portions From 
             
             
               Manufactured Camouflage Construction 
             
          
         
         
             
             
             
          
             
                 
               Force Required 
               Percent 
             
             
                 
               to Break- 
               Elongation at 
             
             
                 
               Peak Load 
               Peak Load 
             
             
               Sample 
               lbf (Mean) 
               (%) (Mean) 
             
             
                 
             
          
         
         
             
             
             
          
             
               A 
               1.705 
               34.897 
             
             
               B 
               1.490 
               33.209 
             
             
               C 
               1.537 
               33.888 
             
             
               D 
               1.947 
               15.676 
             
             
                 
             
             
               Test Method ASTM D2256 
             
             
               Gage Length 10.00 in. 
             
             
               Initial Speed 10.0 in/min. 
             
             
               Ten specimens per sample were averaged to obtain mean values set forth above. 
             
          
         
       
     
   
   
     
       
         
             
           
             
               TABLE 3 
             
           
          
             
                 
             
             
               Seam Failure of Manufactured Camouflage Construction by 
             
             
               Forcible Separation of Two Textile 
             
             
               Substrate Layers at the Seam 
             
          
         
         
             
             
             
          
             
                 
               Force Required 
                 
             
             
                 
               to Break 
               Percent 
             
             
                 
               Peak Load 
               Elongation at 
             
             
               Sample 
               lbf (Mean) 
               Peak Load (%) 
             
             
                 
             
          
         
         
             
             
             
          
             
               A 
               48.979 
               43.675 
             
             
               B 
               65.485 
               54.867 
             
             
               C 
               46.464 
               30.618 
             
             
               D 
               21.827 
               33.414 
             
             
                 
             
             
               Testing Method ASTM D1683 
             
             
               Grip Separation 3.000 in. 
             
             
               Test Speed 12.000 in/min. 
             
             
               Five specimens per sample were averaged to obtain mean values set forth above. 
             
          
         
       
     
   
   Brief Summary of Test Results 
   The tensile test results indicate that the various multi-layered camouflage constructions of the invention exhibit surprisingly good results for resisting elongation along the seam. In Table 1, it may be noted that all three examples of the invention (samples A, B, and C) resisted elongation along the seam significantly better than the sample D product. 
   Testing of the integrity of the seam (Table 3) indicated that the three embodiments of the invention exhibit surprisingly good results for seam integrity and strength. That is, the respective seams of samples A, B, and C resisted breakage substantially better than the seam of prior art sample D. All of the samples of the invention showed seam integrity up to at least 46 lbs of force. In fact, Sample B showed seam integrity up to a 65 lbs of force. The prior art sample D, however, failed at a relatively low force reading of only about 21 lbs of force. 
   It is understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions. The invention is shown by example in the appended claims.