Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B21/00—Warp knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes
  • D04B21/14—Fabrics characterised by the incorporation by knitting, in one or more thread, fleece, or fabric layers, of reinforcing, binding, or decorative threads; Fabrics incorporating small auxiliary elements, e.g. for decorative purposes
  • D04B21/16—Fabrics characterised by the incorporation by knitting, in one or more thread, fleece, or fabric layers, of reinforcing, binding, or decorative threads; Fabrics incorporating small auxiliary elements, e.g. for decorative purposes incorporating synthetic threads
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
  • A01G20/00—Cultivation of turf, lawn or the like; Apparatus or methods therefor
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2401/00—Physical properties
  • D10B2401/12—Physical properties biodegradable
• • D—TEXTILES; PAPER
  • D10—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B—INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES
  • D10B2505/00—Industrial
  • D10B2505/20—Industrial for civil engineering, e.g. geotextiles
  • D10B2505/202—Artificial grass
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C13/00—Pavings or foundations specially adapted for playgrounds or sports grounds; Drainage, irrigation or heating of sports grounds
  • E01C13/08—Surfaces simulating grass ; Grass-grown sports grounds
  • E01C2013/086—Combination of synthetic and natural grass

Definitions

• the present invention is directed to an improved surface for sports and other uses
• Natural turf surfaces were used for most outdoor sports, for example, soccer, football, field hockey, cricket, rugby, etc. Natural turf surfaces are
• a natural turf surface is generally preferred for its comfort, feel, grip, and appearance.
• the surface is unsightly and often pockmarked, uneven, and
• the painted areas of the playing surface can create slippery spots within the playing surface, possibly leading to slips and falls by athletes using the playing surface.
• the painted areas can increase the possibility of injury to the athlete and create hard spots that can be uncomfortable or painful to an athlete who falls upon the
• Synthetic surfaces have been used as an alternative to natural turf surfaces.
• Synthetic surfaces generally come in two types, i.e., conventional and sand filled.
• Conventional synthetic is a dense synthetic material that has the appearance of dense grass blades.
• Sand-filled synthetic is a synthetic material similar to conventional synthetic turf, but with greater spacing between the blades, to accommodate a silica sand filling.
• Both the conventional and sand-filled synthetics are placed indoors or outdoors, upon a foundation that may include an asphalt, concrete, wood, or other supporting subsurface along with cushioning mats, water drainage, and water irrigation.
• synthetic turf surfaces are more durable than well-established natural turf surfaces, they are only moderately successful for sports and other uses.
• the most notable disadvantages of synthetic turf surfaces are the discomfort for the players and -3- an increased number of injuries.
• synthetic turf surfaces are generally expensive to put in place and have a life expectancy of 8 to 15 years, if properly maintained, and less if poorly maintained.
• Outdoor synthetic turf surfaces also remove large areas from the ecosystem, reducing natural processes including ground water recharge, oxygen and carbon monoxide balance, temperature modulation, and dust filtration. For these and other reasons, a number of synthetic turf surfaces are currently being converted back to natural turf surfaces.
• the surface includes a foundation and a synthetic turf base that is positioned atop the foundation.
• the synthetic turf base is filled with a layer of growth medium, and includes synthetic fibers mounted in a permeable backing material.
• the synthetic fibers are constructed of a flexible, synthetic material and extend generally vertically upward from the backing material. Natural grass is planted in the layer of growth medium.
• the backing material is formed of a woven material.
• the woven material is provided with some in-plane stability by having the strands of the woven material fused along the edges of the synthetic turf base.
• the woven material may be formed of nonbiodegradable strands, or may be partially or completely formed of biodegradable strands.
• the backing material is formed of a knitted or multi-ply knitted material.
• One, two, or more layers of knitted material may be used together to provide in-plane stability, while at the same time providing a sufficiently porous backing to allow passage of water and grass roots.
• a secondary backing may be applied to the underside of the knitted backing to further secure attachment of the synthetic fibers to the knitted backing.
• a secondary backing may be formed of, for example, a needle-punched biodegradable material or a light application of a biodegradable or nonbiodegradable latex material.
• the backing is a mesh having the synthetic fibers tufted into the backing.
• the backing may be formed of a nonbiodegradable material or may be partially or completely formed of biodegradable material.
• the layer of growth medium may be filled to a level that is below, at, or above the top of a first or second group of fibers of varied lengths.
• Natural grass is planted in the growth medium so that the roots grow downward through the growth medium, through the backing material, and into the foundation. The blades of the grass grow upward from the top of the growth medium to form a playing surface.
• the playing surface of the present invention improves the durability and visual appearance of natural grass playing surfaces.
• the playing surface of the invention helps to protect the crowns of the natural grass plants, thus helping to prevent damage to the natural grass. This allows the present invention to produce a playing surface that recovers more quickly than natural grass playing surfaces.
• the playing surface of the present invention is formed substantially of natural grass blades, thus providing the comfort and appearance of a natural grass playing surface.
• FIGURE 1A is a cross-sectional view of an embodiment of an improved
• FIGURE IB is an enlarged cross-sectional view of a portion of the
• FIGURE 2 is a partial cutaway view showing the construction of the
• FIGURE 4 is a cross-sectional view of another embodiment of the invention.
• FIGURE 3 is a cross-sectional view of still another embodiment of the
• FIGURE 4 is a top plan view of a knitted backing suitable for use in the
• FIGURES 1 A An improved surface 100 according to the invention is illustrated in FIGURES 1 A.
• the improved surface 100 includes a foundation 102 upon which is mounted a
• the foundation 102 is constructed of a subgrade 106 and a subbase
• the subgrade 106 is constructed for providing a structural base.
• the subgrade 106 may -6- be formed of earth and rock existing on the site as is known in the art. Further, piping (not
• subbase 108 may be placed in or on the subbase 108 to provide drainage and/or irrigation to the subbase 108.
• a subgrade for use with the invention may be readily provided by those skilled
• the subbase 108 is positioned atop the subgrade 106 and is constructed
• the subbase 108 is further constructed to provide structural support
• the subbase 108 may be constructed of any combination of materials known to those skilled
• the subbase 108 may be readily constructed by those skilled in the art.
• a first filter (optional) 109 is positioned
• the first and second filters 109 and 111 may each comprise a fabric or other material constructed to
• the first and second filters 109 and 111 are further constructed
• Adequate filters 109 and 111 may readily be selected by those skilled in the
• the present invention is intended, among other uses, for use as a sports
• subgrade 106 and subbase 108 may be modified to suit the particular
• subbase 108 (or alternatively, a modified subgrade 106) upon which the synthetic turf
• base 104 can be supported.
• the synthetic turf base 104 includes a multiplicity of synthetic fibers 110 that are tufted, or otherwise secured, to a flexible, porous backing 112 having a plurality
• the synthetic fibers 110 are constructed of a synthetic material that is
• the synthetic fibers 110 each extend generally upward from one
• the synthetic grass fibers 110 are of sufficient length that the top portions 114 are
• one alternative embodiment uses -8- synthetic fibers that are 33 millimeters in length and have a density of 13 synthetic grass fibers per 10 centimeters, and another uses synthetic grass fibers that are 15 millimeters in length and have a density of 8 to 10 synthetic grass fibers per 10 centimeters.
• the synthetic turf base 104 is of a type similar to
• backing material have sufficient openings, and that the density of the synthetic fibers be
• the flexible backing 112 is provided for positioning the synthetic fibers
• the flexible backing 112 provides structural support to the improved surface 100 by distributing the force of impact upon the
• the flexible backing 112 includes a plurality of openings 116 through which grass roots and water may pass.
• the openings 116 may be holes punched or otherwise formed in the
• the synthetic turf base 104 further includes a surface layer of growth
• the surface layer of growth medium 118 fills the synthetic turf base 104 from the
• the improved surface 100 further includes natural grass 120 that is planted in the surface layer of growth medium 118.
• the natural grass 120 includes a
• multiplicity of grass blades 122 each having a crown 123 (FIGURE IB) and roots 124
• the natural grass 120 is planted in the surface layer of growth
• the natural grass 120 is planted in the surface layer of growth medium
• growth medium 118 as is known in the art.
• natural grass seeds are sown
• the seeds germinate and the surface is established. Generally, it is desirable to position
• the crown 123 may be positioned at varying distances from the top of
• the surface layer of growth medium depending upon a variety of factors, e.g., the type of natural grass 120 and the composition of the surface layer of growth medium 118.
• grass that propagate by stolons e.g., Zoysia, bentgrass, etc., sprigs or plugs of natural grass will be inserted into the surface layer of growth medium 118 so that the crowns
• the synthetic fibers 110 provide protection to the crowns 123, which is particularly advantageous during periods of heavy use and/or poor
• the synthetic fibers 110 help to protect the crown 123 and the roots 124 of the natural grass 120, thereby minimizing the time required for the grass blades 122 to regrow at times when the improved surface 100 is -10- being reestablished.
• the synthetic fibers 110 also provide a surface with a smoother
• fibers 110 protects the crown 123 and roots 124 to protect the improved surface 100 from deterioration.
• the subgrade 106 is prepared by forming trenches 400 and adding drainage
• the first perforated filter 109 is added atop the subgrade 106, if desired, and is followed by formation of the subbase 108. If the second perforated filter
• the filters 111 is desired, it is placed upon the subbase 108 followed by the synthetic turf base 104, including a surface layer of growth medium 118. It should be noted that the filters
• filters 109 and 111 are optional and one or the
• crowns 123 and roots 124 can form, as described above.
• the subbase 108 is constructed to provide
• the surface layer of growth medium 118 may comprise a variety of materials for supporting the natural grass 120.
• the -11- surface layer of growth medium 118 is a mixture of sand and rubber particles.
• the surface layer of growth is a mixture of sand and rubber particles.
• the medium may comprise a variety of materials for supporting the natural grass 120.
• the surface layer of growth medium 118 in sufficient quantity to extend from about one
• the selection of adequate materials for the surface layer of growth medium 118 is not as limited as with sand-filled synthetic turf
• the roots 124 of the natural grass 120 provide some resiliency to movement in the synthetic turf base 104, compaction is reduced. Still -12- further, the grass blades 122 of the natural grass 120 protect the user from abrasion
• top portions 114 do not extend substantially beyond the surface
• the synthetic fibers protect the crown
• Another advantage of the invention is that the grass blades 122 of the
• natural grass 120 shield sunlight from the synthetic fibers 110 of the synthetic turf base 104, substantially reducing the breakdown of the synthetic fibers 110 due to ultraviolet
• ultraviolet light breakdown increases the expected life of the improved surface 100
• the size and number of openings can also be used.
• biodegradable fibers to form such material so that, after the
• the roots 124 will provide integration of the synthetic turf base 104 to the subbase 108 beyond any
• the flexible backing 112 is constructed from a knitted or multi-ply knitted
• the synthetic fibers 110 are tufted into a knitted
• FIGURE 4 is a top view of one example of a knitted backing material 802 to be used in this embodiment.
• the knitted backing material 802 is knitted from fibers or
• the knitted backing material 802 includes a plurality of openings 116 that are sufficient in
• One example of a suitable knitted backing material is sold commercially for
• backing materials may be used, as long as they are porous enough to allow the grass roots
• the knitted backing material 802 may suitably
• transverse single-strand fibers 804 knitted to longitudinal multistrand looped fibers 806. It should be understood, however, that a knitted backing material suitable for
• the knitted backing material 802 may include all or a portion
• biodegradable threads or fibers or a biodegradable secondary backing as described
• the knitted backing of the present invention may utilize one or more layers
• a preferred embodiment of a knitted backing 800 utilizes two layers or plies of knitted backing material.
• a first knitted ply 802 overlies
• one or more layers of knitted backing material 802, 808 may be fused or calendered using a heated roller adjusted in degree of temperature
• the knitted backing 800 itself becomes difficult to warp or deform during tufting. This makes it easier to install and maintain the synthetic turf base 104 that is supported by the
• the present invention includes the use of a single ply that is fused or
• knitted backing material provides greater structural strength and possibly more tuft lock.
• a combination of two layers having different degrees of porosity suitably provides both of these advantages.
• one or more of the layers to be combined may be calendered prior to or after combination, as discussed above.
• a secondary backing (not shown) may be applied on the underside of the knitted backing 800.
• the secondary backing helps to further secure the tufting, or attachment, of the synthetic fibers 110 to the knitted backing 800, i.e., to enhance tuft-lock.
• the secondary backing provides further structural support to the
• One example of a material suitable for forming a secondary backing is
• biodegradable latex material For example, a material made with a medium molecular weight styrene-butadiene rubber (SBR) including 20% starch, 20% urea (nitrogen),
• SBR medium molecular weight styrene-butadiene rubber
• a latex material such as one described above, is sprayed, coated, or
• the application of the secondary backing in this manner cooperates with the -17- knitted backing 800 to assist in positioning the tufted synthetic fibers 110 in place during installation and maintenance of the synthetic turf base 104. Further, the application of a secondary backing material tends to adhere two or more layers of knitted backing material together, to provide additional structural strength to the knitted backing 800. In addition, use of a biodegradable material to form a secondary backing helps the secondary backing to degrade over time, thus allowing more water passage and more dense growth of the natural grass roots through the knitted backing 800, and the secondary backing, over time. It should be understood that materials suitable for use as a secondary backing are not limited to the example described above. Specifically, a secondary backing may be formed of nonbiodegradable material, or may be partially or completely formed of biodegradable material.
• a needle-punched material may be used as a secondary backing to underlie the knitted backing 800.
• a secondary backing formed of a woven material or a mesh or fleece is applied to the underside of the knitted backing 800 before the synthetic fibers 110 are tufted into, or otherwise attached to, the knitted backing 800.
• fleece may be needle punched through the woven backing prior to the tufting of the synthetic fibers 110, as discussed above.
• a needle-punched material may be partially or completely formed of biodegradable material, so that the needle-punched material may degrade over time to allow more water and the grass roots to pass through the secondary backing.
• a needle-punched material may be formed of different biodegradable materials that degrade at different rates to produce a greater degree of porosity in the secondary backing material over time. It should be understood that materials other than a needle-punched material, or -18- a latex material, may also be used to form a secondary backing, all of which serve to further
• the roots 124 of the natural grass 120 grow down into the surface layer of growth medium 118 and through openings in the flexible backing 112
• One advantageous way of installing the improved surface 100 is to
• synthetic turf base may be manufactured in panels of a size readily stored, transported, and
• the synthetic turf base may also be installed, e.g., of approximately 16 inches by 48 inches.
• the synthetic turf base may also be installed, e.g., of approximately 16 inches by 48 inches.
• the synthetic turf base may also be installed, e.g., of approximately 16 inches by 48 inches.
• the synthetic turf base is filled with a surface layer of growth medium that

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• Life Sciences & Earth Sciences (AREA)
• Environmental Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Road Paving Structures (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1999
  • 1999-05-06 AR ARP990102123A patent/AR015071A1/es not_active Application Discontinuation
  • 1999-05-07 EP EP99921806A patent/EP1079679A4/de not_active Withdrawn
  • 1999-05-07 AU AU38919/99A patent/AU3891999A/en not_active Abandoned
  • 1999-05-07 WO PCT/US1999/010137 patent/WO1999056523A1/en not_active Application Discontinuation

Non-Patent Citations (2)

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