HK1119748A - Synthetic turf system having an infill trapping structure - Google Patents

Description

Artificial turf system with infill capture structure

RELATED APPLICATIONS

The present invention claims benefit of the priority date of U.S. patent application No.60/594,267 filed 24/3/2005 and is incorporated herein by reference.

Technical Field

The present invention relates to artificial turf systems and, more particularly, to artificial turf playing surfaces. The present invention utilizes an artificial turf system having infill material on top of a support and interspersed between upwardly projecting monofilament ribbons simulating grass blades having improved appearance and performance.

Background

Artificial turf systems have been in use for over forty years to provide an alternative where actual turf is not possible, practical, or simply undesirable. The artificial turf system that is more desirable in the market comprises infill material between the upstanding synthetic fibre blades that mimic grass blades. The filler material enables various features and characteristics to be imparted to the actual playing surface while at the same time enabling the synthetic fibers to maintain a grass-like appearance. Thus, improved drainage, resiliency, predictability of motion, reduction of injuries, and other advantages can be imparted to the artificial turf surface while maintaining an appealing appearance.

One particular function of the infill in an artificial turf system is in relation to the stabilizing forces for the synthetic fibre blades. The synthetic blades in the infill-type artificial turf system are relatively long (compared to the non-infill system); for example, between 1 * and 2 * inches in length-to provide an optimal surface "feel" and appearance. Thus, to maintain these types of fibers in a generally upright orientation, the height of the filler material relative to the fibers has been applied up to a predetermined depth (or thickness). Also, the filling provides, among other things, a supportive foundation for the synthetic fibers.

However, the presence of the thickness of the filler material incorporates its own problems. The filler material preferably comprises a combination of particulate materials, such as hard particles, a mixture of resilient and hard particles, or resilient particles alone. Also, particulate materials can interfere with the enjoyment of the artificial surface by moving when pedalled by foot, playing a ball, or by direct contact with the player. The movement of the filler is generally referred to as "filler sputtering". The synthetic fibre blades contribute to the diffusion and/or elimination of the filler splash by acting in particular as a barrier for moving the filler material and by stabilizing the filler between the blades.

Traditionally, the combination of fiber positioning and filler retention has been accomplished in part through the use of relatively soft slit-film-type (slit-film-type) polymeric blades. Such blades are typically woven or tufted into a support layer of the artificial grass surface and then formed into a fibrillar network structure to maximize infill support and retention of the infill by the blade. In addition, the free ends of these fibers are bent over the top of the fill to create a fill capture effect. Unfortunately, this has led to problems in certain artificial turf fields, including the tendency of these fibers to flatten into a smooth surface without proper modification.

As an alternative to the slit film type blade, a monofilament blade may be utilized. Monofilament blades for artificial grass are manufactured by extruding a resulting mono-polymeric (or similar) blade from a device such as a spinneret into a long polymeric strand, trimming the strand, and then cutting a single monofilament sheet from the strand. Typically, a plurality of monofilament elements are bundled together at their bases to form a single bundle of blades, which are then tufted to create a supporting layer of artificial grass surface and fibrillated outwardly.

However, a significant problem with using monofilament fibers in this manner is the balance between the fiber characteristics required for proper installation of the surface, and the fiber characteristics that ensure the best surface conditions for game play and/or surface use. Typically, in order to properly install the infill on the artificial grass surface, relatively rigid/stiff monofilament fibers must be utilized so that the monofilament bundles are not buried under the infill when the infill is being applied.

After the filling has been applied to the desired depth, the free ends of the monofilament fibers (those ends extending above the top of the filling) stand substantially upright. While this type of fiber positioning does provide certain benefits-such as balls rolling closer to the way they roll or bounce on the natural turf surface-it unfortunately also leads to certain undesirable side effects. In particular, unlike the free ends of softer fibers, which fold or bend as the ball rolls over them, such an effect is not as prevalent when using stiffer fibers. Accordingly, as the ball rolls over the top surface of a synthetic playing surface using such stiffer fibers, the filler material becomes more mobile, resulting in significant amounts of filler splattering during game play.

On the other hand, the use of soft fibers also creates problems. While fibers may help reduce filler splatter during game play, they may make filler application more difficult during installation and may result in less than desirable resistance to ball rolling and ball bounce during use. Similar to traditional carpet-type surfaces, rolling or bouncing balls experience "slippage" problems on soft fiber surfaces. Slip problems include unexpected frequent jumps, lack of grass-like rolling response, and slippage on the spinning balls as they contact the artificial grass surface.

It is therefore an object of the present invention to overcome these and other problems associated with conventional artificial turf systems. These and other objects will become apparent to those skilled in the art from the present specification, claims, and drawings appended thereto.

Disclosure of Invention

The object of the invention is an artificial turf system comprising a support member and a layer of granular material spread over the support member. A plurality of monofilament ribbons, preferably in bundles, are operatively connected to the support member. Each bundle may comprise only a plurality of soft or hard ribbons, or may comprise a combination of soft and hard ribbons. The bundles of monofilament ribbons may be configured in various geometric patterns within the artificial turf system; including but not limited to parallel and/or intersecting straight or curved rows, circles, rectangles, and the like. The soft ribbon and the hard ribbon each include a free end that extends out of and over the layer of particulate material, wherein the hard ribbon is substantially less upstanding over the layer of particulate material than the soft ribbon.

Another aspect of the invention is directed to an artificial turf system comprising a support member and a layer of granular material disposed over the support member. A relatively stiff monofilament ribbon having free ends is operatively connected to the support member with the free ends of the stiff monofilament ribbon extending through and over the layer of particulate material. The relatively soft monofilament ribbon, as compared to the stiff monofilament ribbon, includes a free end and is operatively connected to the support member with the free end of the soft monofilament ribbon extending through and over the layer of particulate material. The soft monofilament ribbon further comprises means for capturing the particulate material such that the soft monofilament ribbon is substantially less upstanding above the layer of particulate material than the stiff monofilament ribbon.

Yet another aspect of the invention is directed to a method of installing an artificial turf system. Wherein a support member comprising a relatively soft monofilament ribbon and a relatively stiff monofilament ribbon is positioned above the support base. A layer of particulate material is interspersed over the support member such that the soft monofilament ribbon and the stiff monofilament ribbon extend through and over the layer of particulate material. The soft monofilament ribbon comprises means for capturing particulate material wherein application of the external element thereto causes the soft monofilament ribbon to stand substantially less upright above the layer of particulate material than the stiff monofilament ribbon.

The means for capturing the particulate material may comprise a material integral with or coated onto the soft monofilament ribbon such that its response to an external element causes shrinkage, curling, coiling, bending, etc. Alternatively, the means for capturing the particulate material may also comprise a monofilament ribbon having a geometric structure, such as cross-section (trilobal, star, etc.) and texture; the soft monofilament ribbon may thus be formed into a captured form.

A particular type of soft monofilament ribbon may comprise a multi-stranded monofilament ribbon, including two or more monofilament ribbons having an extruded spider web or net-like structure therebetween. Another type of geometry utilized in soft monofilament ribbons may include fault lines therein. In addition, the soft monofilament ribbons may be configured such that the structural integrity of at least the free ends (the area above the fill material) facilitates folding, or bending-to cover portions of the fill material.

In yet another aspect of the invention, six to eight monofilament fibers or ribbons (it being understood that the terms "ribbon" and "fiber" are interchangeable) are bundled together and include at least three stiff monofilament ribbons and at least three soft monofilament ribbons within the bundle.

Another aspect of the present invention is directed to an artificial turf system that utilizes a micro-fiber material attached to a support member and/or embedded within a layer of granular material to aid in the stabilization or capture of the infill material.

Drawings

FIG. 1 is a side cross-sectional view of an artificial grass surface comprising monofilament bundles of the present invention;

FIGS. 2a-2c are perspective views of a monofilament bundle in accordance with one of several aspects of the present invention;

FIG. 3 is a side cross-sectional view of an alternative embodiment of an artificial turf system according to the present invention;

FIG. 4a is a perspective view of a spinneret for extruding a plurality of monofilaments according to the present invention;

FIG. 4b is a side view of a multi-stranded monofilament in accordance with the present invention;

FIG. 5a is a perspective view of a fault-line monofilament in accordance with the present invention;

FIG. 5b is a side view of a bundle comprising at least one fault line monofilament;

FIG. 6 is a side cross-sectional view of an alternative embodiment of an artificial turf system according to the present invention; and

figures 7a-7c are schematic diagrams of top views of portions of an artificial turf system depicting several layouts of fiber bundles.

Detailed Description

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one or more embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.

Referring to fig. 1, there is shown an artificial turf system 10 of the present invention comprising a flexible support member 12 and a plurality of monofilament bundles 14 projecting upwardly through a bottom side 16 and upwardly from a top side 18 of the support member 12. Between the monofilament bundles 14 and on the noted top side 18 of the support member 12 is a filler material 20 that helps support at least some of the monofilament bundles 14 in a relatively upright position relative to the support member 12. These elements cooperate to form an improved artificial turf system having optimal aesthetic and functional properties.

The support member 12 of the artificial turf system 10 can comprise one or more layers of flexible material that can function as a support structure for the artificial turf system 10. With respect to conventional support materials, the support member may be extruded, woven, non-woven, or a combination thereof.

The monofilament bundles 14 are operatively connected through and to the support members 12 by any number of means known to those of ordinary skill in the art. For example, the monofilament bundles 14 may be woven, knitted, or tufted into the support member 12, leaving a top portion 22 of the bundles 14 above the top side 18 of the support member 12 and a bottom portion 24 of the bundles below the bottom side 16 of the support 12. Thereafter, the bottom portion 24 uses known mechanisms. Such as but not limited to adhesive or stitching.

Generally, the monofilament bundles 14 are secured to the support member 12 in generally straight, parallel rows; and may then be fibrillated to fill the voids between the rows. Alternatively, a support moving device or moving needle bar may be used to move the bundles from a straight tufting, knitting, or weaving, thereby offsetting one or more bundles within a row.

A filler material 20 is placed on the top side 18 of the support member 12 and between the monofilament bundles 14. The filler material 20 may include any number of combinations of conventional particulate materials including hard particles, elastomeric particles, and combinations thereof. Some typical hard particulate materials include sand, rock, and hard and heavy plastics; and typical elastomeric particulate materials may include: rubber (including low temperature), cork, styrene, epdm rubber, used tires, and neoprene.

One embodiment of the monofilament bundle 14 is shown in isolation in fig. 2 a. As can be seen, the monofilament bundle 14 comprises a bundle 30 of monofilament polymeric fibers, the bundle 30 of monofilament polymeric fibers comprising at least one stiff fiber 32, and at least one soft fiber 34. In other words, each bundle 30 may include only soft fibers 34 or only hard fibers 32 as shown in fig. 2b and 2 c. The monofilament fibers 30 are bundled together around one end using a binder 36.

The terms "hard" and "soft" are used to describe the relative flexibility of each of the monofilament fiber types. The stiff strap comprises a strap having a free end positioned above the top of the infill, the free end remaining generally upright without additional supportive infill. Soft straps, on the other hand, comprise straps that are easily bendable so that they do not stand upright like stiff straps without supportive padding. The stiff ribbons can be made of a polymer having higher stiffness, tensile strength, toughness, durability, or structural integrity, or the polymer results in an artificial turf field having higher abrasion resistance than the soft ribbons. For example, the stiff ribbon can be made from a polymer having a high molecular weight, or the polymer can comprise a particular geometry extruded from a spinneret having a particular cross-section, such as round, star, trilobal, or the like. Similarly, the stiff tapes may comprise a plurality of individual monofilaments that are tied or otherwise bonded together to form a stiffer monofilament element.

The composition of the soft tape may comprise the same or similar polymer as the hard tape, but for example at a lower molecular weight. Similarly, the soft band may be formed of an entirely different geometry, or include entirely different polymers together, such as polyethylene, polypropylene, or nylon. In fact, the relative flexibility of the "soft" and "hard" bands may be altered by any number of conventional means, including increasing or decreasing the polymerization of the material, the reactivity toward mating components, the addition of flexible or rigid additives, copolymerization, or the like.

By using a combination of soft and stiff straps within the bundle 14, it is possible to vary the playing and aesthetic characteristics of the field as desired. Thus, the slippage or rolling of the ball on the playing surface can be reduced by adding more "hard" bands to the field (at least relative to their "free" ends), while the undesirable sputtering effects can be reduced by adding more "soft" bands to the field. Furthermore, the field characteristics may also be varied by increasing or decreasing the number of monofilament fibers in each monofilament bundle, by increasing or decreasing the number of monofilament bundles in the artificial grass surface, or by increasing or decreasing the spacing between each monofilament bundle.

It may be desirable to have more than two levels of blade stiffness within the surface so that at least one extremely stiff monofilament ribbon or at least one extremely soft monofilament ribbon may be included in the artificial surface. By adding multiple levels of firmness to the monofilament ribbons within the surface, various playing characteristics can be imparted. Indeed, due to the adaptive configuration of the present invention, specific playing characteristics may be imparted to specific areas of the artificial surface, if desired. That is, the dedicated soft leash, the dedicated stiff leash, and the combination of soft and stiff leash may be configured in various patterns and geometries within the artificial turf system, as desired; some examples of which are shown in fig. 7a-7 c.

In order to minimize infill splash during actual use of the artificial turf system, an alternative embodiment of the present invention, which aims to minimize infill splash during actual use, is shown in fig. 3 and depicts a monofilament bundle 40 comprising at least one stiff (vertical) ribbon 42, and at least one soft (capture) ribbon 44; both of these straps include ends that are crimped onto the support member 12 and respective opposite free ends that extend above the upper surface 46 of the filler 48. In this embodiment, the vertical stiff strips 42 extend over the infill 48 to create a grass-like appearance for the artificial surface, while the soft strips 44 act as catches or stabilizers for the infill to generally retain the infill within the artificial grass surface.

The vertical strips 42 may comprise standard artificial grass blades, or the stiff blades described above, which extend through and over the infill 48 to create a grass-like appearance. The capture zone 44, on the other hand, comprises an artificial grass band having a structure that facilitates "capturing" or stabilizing the surrounding infill 48. For example, the capture band 44 may comprise an artificial grass band that includes inherent or extrinsic structures or characteristics, wherein the band has a tendency to lean, curl, coil, wind, or bend after installation or as a result of the action of an external element, such as heat, cold, light, fluid; this may be achieved by the selection of certain temperature, chemical, or photosensitive materials, for example polymers or resins, such as nylon, or by the selection of certain coatings or additives for the polymeric tape.

In addition, the soft capture zone 44 may facilitate capturing or stabilizing the filler 48 by a particular geometric configuration or shape of the zone. For example, the band may have a cross-sectional shape (such as the trilobal embodiment described above) that restricts movement of the filler 48 around the monofilament band. The belt is shaped or textured by processes such as steaming or gear crimping, etc. Further, the capture belt 44 may comprise entangled fibers, such as a loose continuous filament type belt, that comprise an entangled extrusion of a plurality of micro-fibers or smaller extruded polymeric fibers.

On the other hand, the stiff strap 42 may include inherent or extrinsic structures or properties that promote its rigidity as compared to the soft strap 44, wherein the stiff strap may have a tendency to strengthen, harden, strengthen, etc. after installation as a result of application of external elements, such as heat, cold, light, fluid; this may be achieved by selection of a temperature, chemical, or photosensitive component.

Another alternative embodiment of the invention is shown in fig. 4a and b. In fig. 4a, a plurality of filaments 50 are shown as being extruded from a spinneret 52. The multi-strand monofilament 50 includes at least two monofilament strands 54 (and is shown as having three strands), and an ultra-thin slit film extrusion 56 connecting the monofilament strands 54. The slit film extrusion creates thin polymeric bonds between the monofilament strands 54 that separate into a spider web or net-like structure between the monofilament strands after the traditional post extrusion process of stretching and relaxing (as shown in fig. 4 b). These monofilament strands 54, when bundled together, can fulfill both the functionalities of rigid, vertical fibers and capture fibers.

A further embodiment of the invention is shown in fig. 5a and 5 b. In fig. 5a, a fault-line monofilament 60 is shown comprising extruded monofilament fibers 62 having at least one fault line 64 thereon. The fault line 64 provides a fracture or fraying point (fraying point) for the monofilament fibers 62 such that the monofilament fibers 62 fracture and/or fray after installation into an artificial turf field. The fault line monofilaments 60 can be combined into a bundle (as in fig. 5 b) and then frayed or broken to form a stable net or mesh structure for the surrounding fill 48. Generally, only a portion of the fault line monofilament 60 fiber will split or fray in practice, so that the fault line monofilament 60 can be combined with standard, stiff, or vertical monofilament fibers, or can simply serve as a binder for its own handling.

Preferably, each monofilament bundle comprises between six and eight monofilament fibers, comprising one or more that are not bendable, i.e. rigid or vertical, and one or more tapes that facilitate the trapping of the filling, i.e. soft or trapping tapes. The desired combination between the characteristics of the two types of tapes can be determined without undue experimentation, but preferably a bundle comprises at least three soft tapes and three or more stiffer tapes. Of course, other combinations of multiple monofilament fibers, as well as relative rupture of the soft and stiff ribbons within the bundle, may be configured as desired.

Although the above description focuses on the structure and texture of monofilament fibers to achieve the desired balance between playing properties and infill control, the present invention also enables infill control through direct control of the infill material. Thus, in one embodiment of the invention shown in fig. 6, the artificial grass surface 70 comprises: a vertical belt 72 of any conventional type, including a monofilament-type belt; and fillers 74 interspersed between the bands. The filler 74 additionally includes micro fiber strands 76 interspersed between the filler. The micro fiber strands 76 may include any number of micro fiber structures, such as small pieces of a polymer or the like, which may help stabilize and/or hold the filling in place during play. Preferably, the micro fiber strands 76 are made of a material having a relatively low melting point, such as low density nylon, wherein the micro fiber strands 76 may partially melt or deform during use and play; thereby entangling itself with the filler material.

It should be emphasized that the above-described embodiments of the present invention, particularly, any "preferred" embodiments, are possible examples of implementations set forth merely for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiments of the invention without departing substantially from the spirit and principles of the invention. All such modifications are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.

Claims (32)

1. An artificial turf system comprising:

a support member;

a layer of particulate material dispersed over the support member; and

a plurality of artificial bands operatively connected to the support member, the artificial bands comprising soft monofilament bands and stiff monofilament bands, each of the soft and stiff monofilament bands comprising a free end extending outside and over the layer of particulate material, wherein the stiff monofilament bands are substantially more upstanding above the layer of particulate material than the soft monofilament bands.

2. The artificial turf system of claim 1 further comprising a plurality of bundles of artificial ribbons wherein the bundles comprise at least one stiff monofilament ribbon.

3. The artificial turf system of claim 1 further comprising a plurality of bundles of artificial ribbons wherein the bundles comprise at least one soft monofilament ribbon.

4. The synthetic turf system of claim 3 wherein the bundle comprises at least one stiff monofilament ribbon.

5. The synthetic turf system of claim 1 wherein the soft monofilament ribbon includes means for capturing particulate material.

6. The artificial turf system of claim 5 wherein the means for capturing particulate material comprises a multi-monofilament ribbon including an extruded mesh structure therebetween.

7. The artificial turf system of claim 5 wherein the means for capturing particulate material includes a characteristic that is physically sensitive to application of an external element.

8. The artificial turf system of claim 7 wherein the characteristic comprises a thermally sensitive monolithic polymer or resin.

9. The artificial turf system of claim 7 wherein the characteristic comprises a coating of a heat sensitive polymer or resin.

10. The artificial turf system of claim 5 wherein the means for capturing the particulate material comprises a soft monofilament ribbon comprising a geometry such that the soft monofilament ribbon stands substantially less upright above the layer of particulate material than the stiff monofilament ribbon.

11. The artificial turf system of claim 10 wherein the geometry is a cross-section of a soft monofilament ribbon.

12. The synthetic turf system of claim 10 wherein the geometry is a texture of the soft monofilament ribbon.

13. The artificial turf system of claim 10 wherein the geometry comprises a fault line within a soft monofilament ribbon.

14. The artificial turf system of claim 1 further comprising:

a plurality of micro-fiber strands embedded within the layer of particulate material.

15. An artificial turf system comprising:

a support member;

a layer of particulate material dispersed over the support member;

a hard monofilament ribbon having a free end and being operatively connected to the support member, wherein the free end of the hard monofilament ribbon extends through and above the layer of particulate material; and

a soft monofilament ribbon having a free end and being operatively connected to the support member, wherein the free end of the soft monofilament ribbon extends through and over the layer of particulate material, the soft monofilament ribbon further comprising means for capturing the particulate material of the layer such that the soft monofilament ribbon is substantially less upstanding above the layer of particulate material than the stiff monofilament ribbon.

16. The artificial turf system of claim 15 further comprising a bundle comprising a plurality of monofilament ribbons.

17. The synthetic turf system of claim 16 wherein the bundle comprises a soft monofilament ribbon.

18. The synthetic turf system of claim 16 wherein the bundle comprises a stiff monofilament ribbon.

19. The synthetic turf system of claim 18 wherein the bundle comprises a soft monofilament ribbon.

20. The synthetic turf system of claim 19 wherein the bundle comprises a combination of at least six stiff or soft monofilament ribbons.

21. The artificial turf system of claim 15 wherein the means for capturing the particulate material of the layer comprises a multifilament ribbon including an extruded mesh structure therebetween.

22. The artificial turf system of claim 15 wherein the means for capturing the particulate material of the layer includes a characteristic that is physically sensitive to application of an external element.

23. The artificial turf system of claim 22 wherein the soft monofilament ribbon comprises a thermally sensitive integral polymer or resin.

24. The artificial turf system of claim 22 wherein the soft monofilament ribbon comprises a coating of a heat sensitive polymer or resin.

25. The synthetic turf system of claim 15 wherein the means for capturing the particulate material of the layer comprises a soft monofilament ribbon comprising a geometry such that the soft monofilament ribbon is substantially less upstanding above the layer of particulate material than the stiff monofilament ribbon.

26. The synthetic turf system of claim 25 wherein the geometry is a cross section of a soft monofilament ribbon.

27. The synthetic turf system of claim 25 wherein the geometry is a texture of the soft monofilament ribbon.

28. The synthetic turf system of claim 25 wherein the geometry comprises a fault line within the soft monofilament ribbon.

29. The artificial turf system of claim 15 further comprising:

a plurality of micro-fiber strands embedded within the layer of particulate material.

30. A method of installing an artificial turf system comprising the steps of:

placing a support member over a support substrate, the support member comprising a soft monofilament ribbon and a stiff monofilament ribbon operatively connected thereto, the soft monofilament ribbon comprising means for capturing particulate material; and

a layer of particulate material is placed on top of the support member such that a portion of the soft monofilament ribbon and a portion of the hard monofilament ribbon pass through and extend over the layer of particulate material.

31. The method of claim 30, further comprising:

the means for capturing the particulate material of the layer is exposed to the external element so that the soft monofilament ribbon is substantially less erect above the layer of particulate material than the stiff monofilament ribbon.

32. The method of claim 30, further comprising:

the micro-fiber strands are placed within a layer of particulate material.