AU2008224347A1 - Natural turf replacement system - Google Patents

Description

00 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT

APPLICANT:

INVENTION TITLE: WINTER, Richard; DARBY, Gavin; SNOW, Anthony.

NATURAL TURF REPLACEMENT SYSTEM The following statement is a full description of this invention, including the best method of performing it known to me: -2- 00 NATURAL TURF REPLACEMENT SYSTEM 5 Field of the Invention The invention relates to turf surfaces and more particularly to sports turf surfaces.

Whilst the invention may be applied to any particular turf application, for convenience sake it shall be described herein in terms of a natural turf replacement system which is designed for use where constant maintenance and replacement of the turf surface is necessary such as athletic fields and sports stadiums.

00 Background SGenerally, in applications where a stable, maintenance free surface is required for a variety of uses particularly where the turf surface Will undergo a large degree of wear and stress, artificial turf surfaces are employed. The surfaces are comprised of an artificial mat with synthetic fibres extending upwardly from the mat to give the appearance of natural grass but provide a more resistant and stronger alternative.

The disadvantages with these synthetic surfaces is that they fail to provide the feel and playing characteristics of natural grass and can be quite uncomfortable to play on.

As a result composite turf surfaces have been designed to provide sufaces which have a more natural-look and feel. These composite turf surfaces comprise a planar 2-dimensional artificial mat with a plurality of synthetic upright fibres extending upwardly from the mat to. provide stability for the natural turf-and natural grass plants which are interspersed between these fibres and grown in sand fill layer. The synthetic fibres are slightly higher than height of the grass plants to ensure that the crowns of the grass plants are protected and the turf surface will recover quickly.

The disadvantage of these systems is that when additional layers of top dressing are applied, the uptight fibres become buried meaning that the upright fibres would not be able to perform their intended purpose. In addition, the 2-dimensional artificial mats provide an inhibitive backing which fail to promote root development and allow moisture and nutrient penetration.

Further, the plurality and proximity to the surface of the upright fibres creates a hard surface which detracts from player comfort. As a sports season progresses, there is 0 destruction of portions of a turf surface which causes the playing conditions to deteriorate as the season goes on.

Accordingly, it is an object of the present invention to overcome or substantially ameliorate the disadvantages of the prior art.

Summary of the Invention In accordance with the invention there is provided a replaceable natural sports turf surface which provides a stabilized reinforced natural turf surface that encourages (N 10 integration with the existing growing medium and can be easily harvested,

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00 Otransported and laid wherein the natural sports turf surface is based on an artificial 3cNi dimensional reinforcement layer.

The present invention also provides a natural turf replacement system including: a flexible 3-dimensional reinforcement layer; at least one fill layer; and a plurality of natural grass plants whereby the natural turf surface provides a replaceable stabilized reinforced natural turf surface that encourages integration with the existing sub-surface and can be easily harvested, transported and laid.

It is preferred that a first fill layer comprises a growth media which is adapted to encourage growth of the natural grass plants and root development and allow immediate playability.

It is further preferred that a second fill layer comprises a growth mrnedia which is adapted to encourage growth of the natural grass plants and root development that may be the same of different material to the first fill layer.

It is preferred that the flexible 3-dimensional reinforcement layer comprises a plurality of crossed monofilaments which are thermally welded at specific contact points in a 3-dimensional arrangement which preferably comprises a plurality of pyramid-like mounds.

It is preferred that plurality of natural grass plants are adapted to be seeded within the second fill layer located directly over the reinforcement layer.

The invention also provides a flexible 3-dimensional reinforcement layer for use in forming a stable natural turf replacement wherein the layer extends in a planar -4- 0 arrangement and includes a plurality of spaced peaks to provide 3-dimensional reinforcement of growth media and grasses grown thereon.

The flexible 3-dimensional reinforcement layer can include a means for allowing 5 growth through the reinforcement layer. This can include an open structure of the reinforcement layer or a deterioration or decomposition of the layer.

It can be seen that the invention provides a replaceable natural turf replacement system which provides a stabilized reinforced natural turf surface that encourages S 10 integration with the existing sub-surface and can be easily harvested, transported 00 Oand laid during the sports season to allow for immediate and uncompromised use of Sthe turf surface.

Brief Description of the Drawings In order that the invention can be more readily understood an embodiment will be described by way of non-limiting example with reference to the drawings wherein: Figure 1 shows a top plan view of the 3-dimensional reinforcement layer of a preferred embodiment of natural turf replacement system.

Figure 2 shows a perspective view of the 3-dimensional reinforcement layer of a preferred embodiment of the natural turf replacement system.

Figure 3 shows a side cross-sectional view of the natural turf replacement system according to a preferred embodiment of the invention.

Description of a Preferred Embodiment of the Invention The invention provides a natural turf replacement system 1 which provides a stabilized reinforced natural turf surface 1 that encourages integration with the existing growing medium and can be easily harvested, transported and laid. The natural turf replacement system 1 is preferably adapted to be utilized where constant maintenance and replacement of a turf surface is required such as in a sports stadium or the like. The natural turf replacement system 1 is designed to be installed over a sand or soil field which has been prepared and/or compacted with preinstalled drainage and/or irrigation components. However, it is envisaged that the natural turf 1 could also be used where the subsurface has not be prepared and/or where there are no preinstalled drainage or irrigation components.

The natural turf replacement system 1 of the invention may preferably have provided at least one fill layer. Provided on top of the subsurface may preferably be a first fill 00 layer (not shown) which is preferably comprised of growth media such as sand or soil Sor the like which is adapted to encourage integration with the existing growth medium e and enable immediate playability once it has been laid utilizing specialized machinery Sand experienced operators. The depth of the fill layer may be varied as desired t depending on the particular application.

The natural turf replacement system 1 may preferably have provided a base reinforcement layer 3. The reinforcement layer 3 is preferably in the form of a flexible t' 3-dimensional matting/backing which is adapted to provide reinforcement and N 10 stabilization for the natural turf surface. The 3-dimensional reinforcement layer 3 00 preferably includes a plurality of crossed monofilaments 4 made of a polypropylene Smaterial. It is envisaged that any other suitable material may also be employed provided that the requirements of the invention are met. The length and dimensions of the crossed monofilaments 4 may also vary to produce different types of backings for different turf applications. Reinforcement for the layer may be increased by increasing the thickness of the monofilament strands 4.

The crossed monofilaments 4 are preferably joined together by being thermally welded at specific contact points. The monofilaments4 are preferably joined -together in a 3-dimensional arrangement which is preferably in the form of pyramid-like mounds. Previous turf surfaces are either unreinforced or have provided 2dimensional backing surfaces. Testing of 3-dimeisional synthetic matting structures has shown that there are increased flow rates and root reinforcement for erosion control for both vegetated and unvegetated soil systems. The 3-dimensional arrangement of the crossed monofilaments 4 is preferably adapted to provide an open structured mat where more than 90 percent of the mat is open space to encourage root development through the matting whilst still ensuring that the roots and natural turf 1 has suitable reinforcement.

In an alternate embodiment of the invention, the reinforcement layer 3 may be made of a biodegradable material which is adapted to decompose over time. As the reinforcement layer 3 decomposes it provides further space for the roots to grow and develop and provides additional room for aeration and irrigation of the turf surface.

This may be particularly useful where the natural turf surface 1 of the invention is used for a permanent application rather than a replaceable application. Alternatively, the reinforcement layer 3 may be treated with a decomposition agent to promote 00 acceleration of its decomposition depending on the material of the reinforcement layer 3.

A second fill layer 2 may preferably be provided above the reinforcement mat 3. The 5 second fill layer2 may comprise the same growth media as the first fill layer such as sand or soil, or may comprise another particulate material which is adapted to promote plant growth and provide stabilization. The depth of the second fill layer 2 may vary as desired dependent on the particular application of the turf surface 1 and may be such that, there is provision for an ongoing application of at least one layer of N 10 top dressing provided thereon.

00 SThe natural turf replacement system 1 preferably has provided a plurality of natural grass plants 6 which are adapted to provide a natural grass surface for the invention.

The natural grass plants 6 are preferably grown within the second fill layer 2 provided on top of the flexible reinforcement mat 3 whereby the top portion 7 of the grass plants are preferably adapted to extend upwardly from the second fill layer, whilst the roots 5 of the grass plants preferably extend downwardly .through the flexible reinforced backing 3 and both the second 2 and/or first fill layer. It is envisaged that the second fill layer 2 may be inoculated with microbes to establish a population of micro-organisms which are adapted to encourage growth of the grass plants prior to sodding the natural turf surface 1 and sand is often sterile.

In practice, the natural turf replacement system 1 is preferably initially grown at a sod farm. The natural turf 1 is preferably constructed on compacted slightly sloped land which is covered by a non-porous film such as a polyethylene material 8 or any other suitable material. It is envisaged that the natural turf could also be grown on a full sand profile instead of on plastic film. The 3-dimenisonal layer 3 is then laid onto the film. The second fill layer 2 is then applied over the flexible reinforcement layer to a depth of 35mm using a premium grade turf sand material. The second fill layer 2 is preferably laser graded to ensure there is consistent depth across the entire length of the turf surface. The natural grass plants 6 are then seeded onto the second fill layer 2 and grown to establish a natural grass turf surface.

The natural turf replacement system 1 is preferably maintained in a fashion which allows the profile to be developed to a thickness of approximately 45mm to achieved via a regular application of top dressing. Over time a thatch layer 9 may build up adjacent to the second fill layer 2. The natural turf replacement system 1 is 00 ideally grown for a period of nine months after which time it can be harvested, transported and installed in the desired location. In order to harvest the natural turf a replacement system 1 it is preferred that specialist machinery and experienced j operators be used to form the sod into a roll which is approximately 900mm in J diameter and approximately 800-900kg in weight. This allows for ease of transportation and laying, and to also ensure that the integrity of the natural turf replacement system 1 is maintained.

While we have described herein a particular embodiment of a natural turf C- 10 replacement system 1, it is further envisaged that other embodiments of the invention 00 could exhibit any number and combination 6f any one of the features previously described. However, it is to be understood that variations and modifications can be made without departing from the spirit and scope of the invention as defined in the following claims.

Claims (19)

1. 2. A natural turf replacement system including: a. a flexible 3-dimensional reinforcement layer; N 10 b. at least one fill layer; and 00 c. a plurality of natural grass plants; Swhereby the natural turf surface provides a replaceable stabilized reinforced natural turf surface that encourages integration with the existing sub-surface and can be easily harvested, transported and laid.
2. 3. A natural turf replacement system according to claim 2 wherein a first fill layer comprises a growth media which is adapted to encourage growth of the natural grass plants and. root development and allow immediate playability.
3. 4. A natural turf replacement system according to claim 3 wherein a second fill layer comprises a second growth media which is adapted to encourage growth of the natural grass plants and -root development that is of different material to the first fill layer.
4. 5. A natural turf replacement system according to claim 2, 3 or 4 wherein the flexible 3-dimensional reinforcement layer comprises a plurality of crossed monofilaments which are thermally welded at specific contact points in a 3- dimensional arrangement.
5. 6. A natural turf, replacement system according to claim 5 wherein the plurality of crossed monofilaments which are thermally welded at specific contact points in a 3-dimensional arrangement forms a plurality of pyramid-like mounds.
6. 7. A natural turf replacement system according to claim 6 wherein the plurality of pyramid-like mounds extend for greater than 40% of the depth of the fill layer. -9-
7. 8. A natural turf replacement system according to claim 6 wherein the plurality of 0 Spyramid-like mounds extend for about 50% of the depth of the fill layer.
8. 9. A natural turf replacement system according to claim 3 wherein a plurality of 5 natural grass plants are adapted to be seeded within the second fill layer located directly over the reinforcement layer. A flexible 3-dimensional reinforcement layer for use in forming a stable natural turf replacement wherein the layer extends in a planar arrangement NC 10 and includes a plurality of spaced peaks to provide 3-dimensional 00 Sreinforcement of growth media and grasses grown thereon. (Ni
9. 11. A flexible 3-dimensional reinforcement layer according to claim 10 wherein the spaced peaks are in an equispaced array.
10. 12. A flexible 3-dimensional reinforcement layer according to claim 10 or 11 wherein the peaks are spaced such as to allow constant angle and the base of each peak meet the base of adjacent peak.
11. 13. A flexible 3-dimensional reinforcement layer according to claim 10, 11 or 12 wherein the flexible 3-dimensional reinforcement layer includes a means for allowing growth through the reinforcement layer.
12. 14. A flexible 3-dimensional reinforcement layer according to claim 13 wherein the means for allowing growth through the reinforcement layer includes an open structure of the reinforcement layer. A flexible 3-dimensional reinforcement layer according to claim 14 wherein the open structure of the reinforcement layer includes holes or openings of more than 50% of the surface area.
13. 16. A flexible 3-dimensional reinforcement layer according to claim 14 wherein the open structure of the reinforcement layer includes holes or openings of more than 90% of the surface area.
14. 17. A flexible 3-dimensional reinforcement layer according to claim 14, 15 or 16 wherein the open structure of the reinforcement layer includes a plurality of 0 crossed monofilaments which are thermally welded at specific contact points Sin a 3-dimensional arrangement. e(N
15. 18. A flexible 3-dimensional reinforcement layer according to claim 13 wherein t the means for allowing growth through the reinforcement layer includes biodegradable material of the reinforcement layer that has a natural decay rate to allow growth through the reinforcement layer.
16. 19. A flexible 3-dimensional reinforcement layer according to claim 13 wherein (N 10 the means for allowing growth through the reinforcement layer includes 00oO decomposition agent included in the reinforcement layer that has a natural Cti decomposition rate to allow growth through the reinforcement layer. A natural turf replacement -system according to any one of claims 2 to 9 using a flexible 3-dimensional reinforcement layer according to any one of claims to 19.
17. 21. A replaceable natural sports turf surface substantially as hereinbefore described with reference to the drawings.
18. 22. A natural turf replacement system substantially as hereinbefore described with reference to the drawings.
19. 23. A flexible 3-dimensional reinforcement layer for use in forming a stable natural turf replacement substantially as hereinbefore described with reference to the drawings.