Plant husbandry – Miscellaneous
Reexamination Certificate
1997-11-05
2001-10-02
Poon, Peter M. (Department: 3643)
Plant husbandry
Miscellaneous
C047S05810R
Reexamination Certificate
active
06295756
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed toward an improved surface for sports and other uses.
BACKGROUND OF THE INVENTION
For years natural turf surfaces were used for most outdoor sports, for example, soccer, football, field hockey, cricket, rugby, etc. Natural turf surfaces are surfaces constructed with a grass grown in soil, or some other surface layer of material (e.g., sand and organic mixes, etc.), that is constructed upon a suitable foundation. A natural turf surface is generally preferred for its comfort, feel, grip, and appearance.
However, under heavy use and/or poor weather conditions, natural turf surfaces deteriorate rapidly and maintenance is costly. Intense activity on the turf destroys the grass and its root system, leaving mud and/or dirt as the playing surface. Prior to re-establishment of the turf, the surface is unsightly and often pockmarked, uneven, and possibly hazardous to use.
Another problem associated with natural turf surfaces is the use of painted on yardage and boundary lines. Typically, such boundary lines are formed by painting the playing surface. For aesthetic reasons, such lines are generally painted just prior to each official game played on the playing surface. The repeated application of paint to the surface of the playing surface tends to kill the grass that is located under the painted surface. In addition, over time the multiple layers of paint build up forming a surface that is substantially harder than the surrounding natural grass playing surface. Thus, 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. In addition, 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 that falls upon the painted area.
Due to the needs of sports programs, even after destruction of portions of the turf, play usually continues on the playing surface, even when the surface is badly damaged, until the sport's season is over, when the turf can be re-established. Thus, the playing conditions on the playing surface continually decline over the season. At the end of the season, the natural turf surfaces are reseeded, the divots leveled and filled, etc. The natural turf surfaces are not usable during this re-establishment period because use defeats the re-establishment of the turf. The re-establishment period typically takes at least four months, or longer, under ideal weather conditions, during which the natural turf surface should not be used.
Recently, 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 but is manually placed indoors or outdoors, usually upon an asphalt, concrete, wood, or other foundation. 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.
Although 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 disadvantage of synthetic turf surfaces is the discomfort for the players and an increased number of injuries. Additionally, synthetic turf surfaces are generally expensive to put in place and have a life expectancy of 8-15 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 the natural turf surfaces.
As can be seen from the above discussion, there exists a need for an improved surface for sports and other uses, and a method of making the improved surface, wherein the surface provides improved comfort and fewer injuries to the users, while being durable under heavy use and in poor weather conditions. The present invention is directed toward fulfilling this need.
SUMMARY OF THE INVENTION
The present invention provides an improved surface for sports fields and for other high traffic uses. In one embodiment, the surface includes a foundation and a growth medium filled synthetic turf positioned atop the foundation. The synthetic turf base includes synthetic fibers attached to a permeable backing material with a layer of growing medium filled between the synthetic grass fibers. The synthetic fibers are constructed of a flexible, synthetic material and extend generally vertically upward from the backing material.
In one embodiment, the playing surface includes a foundation and a synthetic turf located on top of the foundation. The synthetic turf includes a backing material and a plurality of synthetic fibers extending generally vertically upward from the backing material. The synthetic fibers are formed of at least a first group of fibers having a first length and a second group of fibers having a second length that is longer than the first length so that the second group of fibers extend upward from the backing material a greater distance than the first group of fibers. A layer of growth medium is disposed in the synthetic turf to a depth sufficient to substantially fill the synthetic grass turf. In various embodiments, the layer of growth material may be filled to a level which is below, at, or above the top of the first group of fibers.
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.
In accordance with other aspects of the invention, the second group of fibers are uniformly interspersed throughout the playing surface. The second group of fibers extend upward and are intertwined with the natural grass blades. The first group of fibers protect the crowns of the grass plants, while the second group of fibers help to protect the blades of the grass plants.
In accordance with other features of the invention, the second group of fibers are formed of a color that contrasts with the grass and provides a visual indicator. The second group of fibers are placed in an organized pattern to provide boundary indicators, line indicators, etc. The backing material in the region of the second group of fibers is formed of a material that is root-impervious. The backing material also includes a herbicide to prevent natural grass plants from growing into and through the backing material in the region of the second group of fibers.
In accordance with other aspects of the invention, the backing material is formed of a woven material. The woven material is provided some in-plane stability through the use of fusing the strands of the woven material along the edges of the synthetic grass turf.
In accordance with yet other aspects of the invention, a mesh material is placed beneath the foundation and the synthetic grass turf. The mesh material is located in the region of adjoining edges of the synthetic grass turf and underlies the adjoining edges of the synthetic grass turf. The roots of the grass plants grow through the synthetic grass turf, through the mesh material, and into the foundation, thus binding different pieces of the synthetic grass turf to the mesh material and the foundation. The mesh material can include protrusions extending from either one or both sides of the mesh material. The protrusions extend into the foundation and into the
Nguyen Son T.
Poon Peter M.
Turf Stabilization Technologies Inc.
Wood Herron & Evans L.L.P.
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