Abstract:
In a needle tufting operation in which at least one needle is caused to penetrate a backing material and tuft synthetic yarn therethrough to form a surface thereon comprising the synthetic yarn, the improvement comprising delivering a plurality of synthetic yarns of differing texture to the same needle for simultaneous insertion through the backing material such that the tuft formed thereby comprises the plurality of yarns of differing texture and the articles produced thereby.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to synthetic sports surfaces and to a method of manufacturing an artificial turf as well as other types of surfaces constructed of synthetic fibers.  
         [0003]     2. Description of the Prior Art  
         [0004]     Tufted surface coverings are employed indoors as floor coverings in the form of carpeting, area rugs, floor, gym, barrier and crash mats, as well as outdoors, in the form of carpeting, artificial turf, cushioned sport and play surfaces and sport mats. Surface coverings for sporting use are generally constructed by stitching into a preformed fabric backing layer to form tufts, and then bonding the primary backing layer to an impact-absorbing resilient lower layer or shock pad, by means of a thin, laminating layer.  
         [0005]     Conventional tufting machines employ rows of needles, which are threaded with a suitable yarn fed from a ball or creel through an aperture adjacent the tip of each needle. The tufting machine forces the rows of needles through a backing fabric. The needles pierce the fabric from back to front, pushing the yarn through the backing. Looping tools catch the yarn loops on the face of the backing as the needles are withdrawn. Once tufting of the primary backing is completed, the loops of face yarn are generally cut to form a pile surface or “face”. While the loops may be left uncut for indoor carpet surfaces, the loops of surfaces intended for outdoor usage are generally cut in order to produce a covering more closely resembling grass. The diameter of the yarn, the number of yarn strands in each tuft, and the spacing of the tufts determine the density of the final surface.  
         [0006]     Conventional tufting machines use a reciprocating needle bar carrying a plurality of aligned needles of a predetermined gauge, the needles being constructed and arranged to reciprocally penetrate a backing material passing beneath the needle bar and over a bedrail. As the needles penetrate the backing materials they each carry a separate yarn which yarn is caught either by a looper to create a looped pile article, or by a hook moving, in timed relationship with a knife to create a loop of tufted material which is then cut to create a cut pile article. It is by these well known processes, that loop pile and cut pile carpeting is made. Typical of the tufting machines currently employed in the art are those disclosed in U.S. Pat. Nos. 2,057,920; 3,026,830; 3,142,276; 3,361,096; 3,645,219 4,132,182; 4,173,192; 4,419,944; 4,440,102; 4,586,445; 4,665,845; 4,829,917; 5,513,586; 5,224,434; 5,706,745; 5,979,344 and British Patents Nos. 1,507,201 and 1,304,151.  
         [0007]     Synthetic turf was originally developed in response to a need for a sports playing surface which could overcome some of the limitations of natural grass turf. The advent of the covered, multipurpose stadium was the impetus of the original development. In its infancy the artificial grass market was almost exclusively limited to textured nylon yams constructed into a carpet like material. The advantages of these systems were as follows:  
         [0008]     (1) Provided excellent traction for the athletes.  
         [0009]     (2) Extremely durability to wear and tear from sports activities.  
         [0010]     (3) Lower maintenance costs compared to traditional grass fields.  
         [0011]     However, these systems also had several major disadvantages as follows:  
         [0012]     (1) Extremely abrasiveness to skin surfaces, requiring athletes to wear special padding and equipment.  
         [0013]     (2) The systems did not have the appearance of natural grass.  
         [0014]     (3) Athletes performing on the surfaces typically required special shoes.  
         [0015]     These disadvantages eventually led to the development of artificial turf systems that consisted of high pile, non-textured polyethylene (PE) yarn which were filled at the job sight with sand and/or rubber particles [U.S. Pat. No. 5,958,527]. The advantage of these systems are as follows:  
         [0016]     (1) The systems have more of an appearance of a real grass playing field.  
         [0017]     (2) The yarn was thought to be less abrasive and typically, it was surmised, did not require special padding for the individual athletes. This misapprehension was based on the misconception that the construction of the nylon fibers in the first generation systems made them abrasive. It was later learned that the lack of texture in the PE fiber lowered their abrasive characteristics more than the change in fiber composition.  
         [0018]     (3) Most systems were sold under the impression that special shoes would not be required, i.e., that the traditional cleats typically used for real grass could be worn.  
         [0019]     However, these systems also suffered from the following disadvantages:  
         [0020]     (1) The requirement for infill material created additional maintenance costs when compared to non-infilled materials.  
         [0021]     (2) The infill material tends to fragment and be pulverized and/or compact during normal wear.  
         [0022]     (3) The infill material, e.g., sand could be abrasive, or, if it were a rubber like material, it would tend to migrate.  
         [0023]     (4) The PE fiber is less durable to wear and tear when compared to nylon fiber.  
         [0024]     (5) One of the characteristics of PE fiber is lower resiliency when compared to nylon, i.e., as the fibers are worn they tend to lay flat and create a surface that becomes slippery thereby requiring the use of special shoes.  
         [0025]     One solution of the above noted problems is suggested in published U.S. application Ser. No. 20030099787. That application utilizes alternating thread-ups of yarn systems for constructing artificial turf systems. The publication discloses a sports surface made of a flexible backing tufted with a combination of yarns of different final lengths and textures. A first yarn is tufted at spaced intervals in the backing to provide first yam segments extending upwardly from the backing suggestive of blades of grass. A second type of yarn is tufted in the intervals between said first yarn, to provide second yarn segments. The second yam segments may be of a conventional texturized yam having a length under tension approximately equal to that of the first yam segments. In the finished surface the second yam segments return to a sinusoidal or kinked form and constitute an under layer having a lower vertical height than the first yam segments.  
         [0026]     It is an object of the present invention to provide a novel synthetic sports surfaces (artificial turf) or other types of carpet surfaces constructed of synthetic fibers that does not suffer from the disadvantages discussed above.  
         [0027]     It is a further object of the invention to provide a novel method for constructing synthetic sports surfaces (artificial turf) or other types of carpet surfaces utilizing synthetic fibers.  
       SUMMARY OF THE INVENTION  
       [0028]     The foregoing and other objects are realized by the present invention, one embodiment of which relates to an improved method of constructing a synthetic sports surface or other type of carpet surface by means of a needle tufting operation in which at least one needle is caused to penetrate a backing material and tuft synthetic yam therethrough, the improvement comprising delivering a plurality of synthetic yams of differing texture to the same needle for simultaneous insertion through the backing material.  
         [0029]     Other embodiments of the invention relate to the surfaces produced by the above-described method.  
         [0030]     Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]      FIG. 1  is a side elevation of a prior art sports surface based on FIG. 2 of U.S. Pat. No. 5,958,527;  
         [0032]      FIG. 2  is a side elevation of a prior art sports surface based on marketing literature;  
         [0033]      FIG. 3  is a side elevation of a prior art sports surface based on FIG. 3 of U.S. Patent Application, Pub. No. 20030099787;  
         [0034]      FIG. 4  is a side elevation of a prior art sports surface based on FIG. 4 of U.S. Patent Application, Pub. No. 20030099787;  
         [0035]      FIG. 5  is a stylized side elevation of an embodiment of the present invention;  
         [0036]      FIG. 6  is a stylized side elevation of another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
       [0037]      FIGS. 1 and 2  illustrate various prior art sports surfaces using in-fill techniques.  
         [0038]      FIG. 1  is a side elevation of a prior art synthetic grass turf assembly as depicted in FIG. 2 of U.S. Pat. No. 5,958,527. The grass turf assembly  10  includes a flexible open weave backing  12  and upstanding synthetic ribbons  14 , which are tufted in spaced-apart rows. An in-fill layer  16  is disposed between the ribbons. The in-fill is made up of sand granules  18  and resilient rubber granules  20 , arranged in layers of different sand-rubber proportions.  
         [0039]      FIG. 2  is a side elevation of a prior art turf system (AstroPlay™) as depicted in marketing literature for the product. The turf system product  20  includes a fiberglass backing  32  and polyethylene fibers  34 . A 100% particulate rubber in-fill  36  is used. Texturized nylon fibers  38  are said to stabilize the fill.  
         [0040]      FIGS. 3 and 4  are side elevation views of the prior art turf systems depicted in FIGS. 3 and 4 of U.S. Patent Application, Pub. No. 20030099787. The sports surface  100  includes a suitable flexible backing such as the open weave flexible backing  102  of a weight sufficient to withstand forces encountered when the surface is in use and to maintain the sports surface in contact with, for example, an adhesive coated playing field substrate surface. A first yam  104  is tufted at spaced intervals in the backing and provides generally upwardly extending segments suggestive of blades of grass. A second yam  106  (and in the case of the product of  FIG. 4 , a third yam  108 ) provides yarn segments in supporting layer  110  below the tops of the first yam segments. In preferred embodiments, the second yam segments  106  (and third yam segments  108 ) are made of a heavy denier knit-deknit yam and have a length under tension approximately equal to the length L of the first yarn segments. The second (and third) yam segments form a layer having a vertical height less than L. The second (and third) yarn segments are sufficiently numerous and of sufficient bulk to maintain the first yarn segments in an approximately vertical orientation in the layer without requiring the addition of particulate fill.  
         [0041]     In contrast to the above, in the present invention, a synthetic sports surface or other type of carpet surface is constructed by means of a needle tufting operation in which a plurality of synthetic yams of differing texture are delivered to the same needle for simultaneous insertion through the backing material. The sports surface of the present invention can be made on conventional carpet tufting machinery. The general tuft arrangement will now be discussed with reference to the side elevations of  FIGS. 5 and 6  which have been simplified to illustrate the tufting procedure. The sports surface  200  includes a suitable flexible backing such as the open weave flexible backing  201  of a weight sufficient to withstand forces encountered when the surface is in use and to maintain the sports surface in contact with, for example, an adhesive coated playing field substrate surface. A first yarn  202  and a second yarn  203  are tufted simultaneously through a single needle at spaced intervals in the backing and provide generally upwardly extending segments  202  suggestive of blades of grass and shorter segments  203  forming a layer having a vertical height less than that of  202 . The second yarn segments are sufficiently numerous and of sufficient bulk to maintain the first yarn segments in an approximately vertical orientation in the layer without requiring the addition of particulate fill. Upper portions of the first yarn segments may lay over somewhat.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0042]     The invention is predicated on the discovery that the disadvantages of the prior art systems can be overcome by utilizing synthetic fibers of different textures in the construction of the artificial turf surface and that such systems may be constructed by tufting the synthetic fibers of differing textures through a single needle. The fibers preferably comprise a straight yarn and a highly textured yarn. The straight yarn provides a less abrasive fiber for athletes to slide upon while the textured yarn provides superior traction as the cleat of the athlete&#39;s shoe penetrates into the turf. The resiliency of the straight nylon fiber and the texturized nature of the second nylon fiber, which offers additional support to the straight nylon fiber, work together to eliminate the need for a particulate infill.  
         [0043]     Although polypropylene, polyethylene or other synthetic yarns can be employed, it is preferred to utilize nylon fibers due to their superior durability characteristics. It is a critical feature of the invention that one of the yarn components comprises a straight non-textured yarn. This contributes to: (1) the artificial turf having the appearance of real blades of grass (2) a low degree of abrasiveness to human skin and (3) a high degree of resiliency such that the turf surface will not easily deform or lay flat. The second yam component comprises a highly textured yam. It will be understood that the second yam component may comprise fibers having one or more texture configurations. The textured component contributes to (1) additional support for the straight non-textured yarn (2) superior shoe traction and (3) a cushion effect and resistance to downward forces, which does away with the requirement for infill particulate.  
         [0044]     It is a further critical feature of the invention that both yarns, the straight non-textured and the highly textured yarns are tufted through the same needle to form the artificial turf. This unique aspect of the method of the invention permits the construction of a novel turf system wherein the texture yarn is positioned adjacent to the non-textured yarn thereby enhancing the above-noted advantageous characteristics of the mixed-yarn turf product. After being tufted together through the tufting needle and cut, the textured yarn which has a length under tension approximately equal to that of the non-textured yarn segments regains its original textured shape by returning to a sinusoidal or kinked form thereby forming an under layer having a lower vertical height than the non-textured yarn segments and wrapping around the non-textured yarn which retains its original length and remains straight and upright. This re-assumption of its original textured shape by the textured yarn provides added support for the non-textured yarn. The textured yarn segments are sufficiently numerous and of sufficient dimension and texture so as to maintain the bases of the nontextured yarn segments in an approximately vertical orientation without requiring the provision of a particulate fill.  
         [0045]     Any conventional tufting machine (such as those disclosed and discussed above) that produces the fibrous face of tufted articles, for example carpets, by tufting individual yarns through a primary backing material or substrate may be used in the practice of the invention. The tufting machine typically has a frame supporting at least one elongate needle bar on which at least one series of spaced tufting needles is disposed. A continuous web of backing material is continuously fed in a warp, i.e., a longitudinal or lengthwise, direction through the tufting machine during the tufting process. Each of the tufting needles is threaded with a suitable combination of yarns to be tufted in the backing material, and the needles are passed together through the backing material by the reciprocating motion of the needle bar as the backing material is moved or carried past the needle bar during machine operation to form tufts in the “face” of the backing material. If so desired, and as known, the tufting machine may be provided with two spaced and parallel needle bars, each of which being provided with a separate series of spaced tufting needles.  
         [0046]     The needle bar is driven through a suitable drive arrangement such that it is reciprocated vertically with respect to the backing material as it is passed beneath the needle bar during a continuous tufting operation. As appropriate, a looper and/or a knife may be placed on the face side of the backing material, in registry with each respective needle, so that loops or cut piles of tufted yarn are formed and remain in the backing material once the tufting needles are drawn by the needle bar back out of the backing material.  
       EXAMPLE  
       [0047]     The yarn used for this trial was 100% nylon and was purchased from Syntec Industries. The yarn is an eight-filament yarn with each filament having a denier [a universal method for measuring and expressing the size of yarn] of 525. Therefore, the entire package has denier of 8×525 or 4200/2 ply.  
         [0048]     The yarn is divided 1) into its natural or untextured state and 2) a textured state. The texture rising was done by processing it through a Dietz. This equipment uses mechanical gears to impact a permanent crimp into the yarn.  
         [0049]     The yarn was put on a creel and fed to a ⅜ gauge tufting machine located at [Intergrated Tufting Center]. The “gauge” of the machine is determined by the number of needles that are positioned on the machine across the width. In this particular case the needles are ⅜ of an inch apart. The width of the machine is 180 inches wide yielding 480 needles. Each needle was fed one texturized fiber and one non-texturized fiber. The fiber pile height was 1-¾ inches. Stitches per inch were 5¼ per inch. Fiber denier, fiber height and the number of stitches per inch equaled 56 ounces per square yard of nylon fiber weight.  
         [0050]     The fibers were tufted into a primary comprising “SportsBac” (Synthetic Industries). This is a woven 15-pic polypropylene. It has a polyester fiber needled into it and an open mesh fiberglass attached also by the needling process.  
         [0051]     The last step consists of coating the backstitches. Approximately 20 ounces per square yard of polyurethane adhesive was used. It was cured and then an 8-millimeter thick polyurethane foam was applied (approximately 80 ounces per square yard) with a non-woven polyester secondary. Holes were drilled in the composite to allow water to pass through the finished synthetic playing surface.  
         [0052]     It will be understood that various combinations of yarn tufts and tuft spacings can be obtained by feeding the appropriate yarn types to selected ones of the tufting needles of a conventional tufting machine.  
         [0053]     Those skilled in the art will be familiar with the types of texturized or textured yarns suitable for use in the present invention. Generally, any texturized yarn suitable for use in the manufacture of carpet or sports surfaces may be used in the practice of the invention. Typical of such textured yarns are those disclosed in U.S. Pats. Nos. 3,298,079; 3,861,133; 4,169,707; 6,076,345 and 4,096,226; European Patent Application, Publication No. EP .0784109 A2; European Patent document EP 485 871B1; German Patent 32 10 784—Japanese Patent Publication No. Showa 45(1970)-24699, Japanese Patent Publication No. Showa 44(1969)-13226, Japanese Patent Application Laid-Open Specification No. Showa 46(1971)-2180 and Japanese Patent Publication No. Showa 46(1971)-23766; German Published Application No. 1,902,213; U.K. Pat. No. 1,170,749; French Pat. No. 1,535,468) and French Pat. No. 1,555,112.  
         [0054]     From the foregoing description, various modifications and changes in the composition and method will occur to those skilled in the art. All such modifications coming within the scope of the appended claims are intended to be included therein. The entire disclosures and contents of each and all references cited and discussed herein are expressly incorporated herein by reference. All percentages expressed herein are by weight unless otherwise indicated.