AU3907199A - Inflatable ground cover - Google Patents

Description

r S F Ref: 471640

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

9 9t* 99 Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: ASSOCIATED PROVISIONAL [31] Application No(s) PP4543 PP4798 Freeform Fabric Structures Pty Ltd 9 Aylesbury Street Botany New South Wales 2019

AUSTRALIA

Paul Gregory McNeill Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Inflatable Ground Cover APPLICATION DETAILS [33] Country

AU

AU

[323 Application Date 7 July 1998 22 July 1998 The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5815 INFLATABLE GROUND COVER Technical Field The present invention relates to devices for covering sections of ground, such as race tracks and sporting fields, to protect the same from inclement weather.

Background of the Invention Race courses are exposed to the elements and consequently can be greatly effected by rainfall which softens the surface and reduces its rating from fast, to good, slow, heavy, and with sufficient rainfall to washed out resulting in the cancellation of events. Heavier and softer tracks present greater safety risks to both the horse and see.

10 rider, and bias the chances of success of different horses. Racing on a soft, heavy track oi also increases the damage to the track surface. No viable covering systems for protecting the track surface are currently available.

~Other sporting field surfaces such as cricket pitches, tennis courts and football fields are also effected by rain softening and damaging the playing surface and 15 increasing the risks to competitors and of play cancellation. Various covers have been employed on such sporting fields. The simplest form of cover is a single skin waterproof sheet which is rolled out onto the surface allowing rain to collect on the surface. The weight of the cover and water lying thereon, which does not readily drain off, can create a significant pressure on the playing surface damaging the same. To reduce the pressure on the surface, air blowers have been used to blow air under the covers, however the edges of such covers need to be sealingly secured to the ground to entrap the air and keep the covers off the ground.

Similar problems also exist in maintaining surfaces being prepared for outdoor events such as concerts and parties.

Object of the Invention It is the object of the present invention to overcome or substantially ameliorate at least some of the above disadvantages.

[N:\LIBLL]01848:GJG:TCW Summary of the Invention There is disclosed herein an inflatable ground cover comprising: a body formed of an upper sheet of flexible, light transmissive substantially water impermeable material and a lower sheet of flexible, light transmissive material, said upper and lower sheets being sealingly secured around edges thereof to form a cavity therebetween, an air inlet communicating with said cavity for inflating said body, and means for securing said body to a ground surface, wherein said lower sheet is adapted to enable air to pass from said cavity through said lower sheet to a ground surface therebeneath.

Preferably said lower sheet material is air permeable.

Alternatively or additionally said lower sheet may be provided with a plurality of apertures for passage of said air from said cavity to said ground surface therebeneath.

Said lower sheet may be formed as a lattice of strips forming said apertures therebetween.

Preferably said apertures constitute between 30% and 60% of the surface area a~.

of said lower sheet.

Preferably said upper and lower sheet materials have a light transmissivity of at least Preferably said upper and lower sheet materials have a UV factor of less than Preferably said upper and lower sheet materials have a mass of less than 300 grams per square metre.

Preferably said upper and lower sheet materials are a fabric.

Preferably said upper and lower sheet materials are a polypropylene fabric.

Preferably said means for securing said body to a ground surface comprises a plurality of eyelets each for receiving an elongate securing element.

Preferably a gutter is provided along an edge of said body.

[N:\LIBLL]01848:GJG:TCW Preferably said gutter is formed by an elongate inflatable lip defining a channel at a junction between said lip and said body at said edge.

Preferably said body is configured to cover a section of race track.

There is further disclosed herein an inflatable ground cover comprising: a body formed of an upper sheet of flexible, substantially water impermeable material and a lower sheet of flexible material, said upper and lower sheets being sealingly secured around edges thereof to form a cavity therebetween, an air inlet communicating with said cavity for inflating said body, .oo.oi S.means for securing said body to a ground surface, and S 10o a gutter provided along an edge of said body.

•ze ~Preferably said gutter is formed by an elongate inflatable lip defining a channel at a junction between said lip and said body at said edge.

S:Preferably said material is light transmissive.

There is further disclosed herein a method of covering a race track or sports 15 field surface comprising the steps of: laying said inflatable ground cover over said surface, securing said inflatable ground cover to said surface, and scrn adifaal rudcvrt adsrae n inflating said body via said air inlet.

Brief Description of the Drawings Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 is a perspective view of an inflatable ground cover.

Figure 2 is a cross sectional view of the ground cover of Figure 1 taken at section 2-2.

Figure 3 is a plan view of the lower sheet of an alternate inflatable ground cover.

[N:\LIBLL]01848:GJG:TCW Detailed Description of the Preferred Embodiments With reference to Figures 1 and 2, an inflatable ground cover 100 has a body 101 formed of an upper sheet 102 of flexible, substantially water impermeable material and a lower sheet of flexible material. The upper and lower sheets 102, 103 are sealingly secured around their edges 104, 105, 106, 107 to form a cavity 108 therebetween. Whilst the upper and lower sheets 102, 103 are here formed as separate pieces and joined along the edges, a small cover body could be formed of a single piece of material folded over to form upper and lower sheets and sealed along the remaining free edges of the folded piece of material. The lower sheet 103 is adapted to enable air S.1. 0o in the inflated body to pass therethrough to the ground surface therebeneath, thus aerating the grass to prevent it from burning and turning brown. Here both the upper S* and lower sheets 102, 103 are formed of a fabric, the air permeability of the fabric allowing the air to pass through the lower sheet 103 to aerate the ground.

The ground cover 100 depicted is suitable for covering a section of race track, and measures approximately 100 m long by 15 m wide. Due to the large size, the upper and lower sheets 102, 103 are each formed of several pieces of material sealingly attached to each other along joint lines 109. The number of pieces required to form each sheet will be dependant on the size of available pieces of material and the size of cover required.

The material should be light transmissive, particularly preferably ultraviolet (UV) transmissive to enable grass to grow beneath the cover 100, thereby enabling the cover to remain in place for extended periods between race meets if desired. The material will preferably have a light transmissivity of at least 60%, and a UV factor of less than 70%. The material should also be lightweight, having a mass preferably less than 300 g/m 2 to avoid high pressure loads on the grass beneath the cover.

The currently preferred material is a polypropylene fabric, sold under the name SOLARWEAVE, and has a light transmissivity of 82% and a UV factor of 50%. The fabric is lightweight having a mass of 180 g/m 2 and is further characterised by having a breaking strength of 750 x 750 N/50mm as measured according to Australian [N:\LIBLL]01848:GJG:TCW Standard 2001.2.10 and 180 x 180 N/50 mm as measured according to Australian Standard 2001.2.3. SOLARWEAVE fabric is also resistant to most acids, alkalis, solvents and agricultural chemicals.

Being a polypropylene fabric, SOLARWEAVE can be plastic welded, and the various joins between the individual pieces of fabric and between the upper and lower sheets 102, 103 along the edges 104, 105, 106, 107 are preferably made using a plastic welding process fusing the two pieces of fabric together using heat and compression. A plastic welding device which has been found to be particularly suitable for welding the ooooo fabric is an automatic floor machine imported from Leister Products. Inc of S 0o Switzerland. Other known devices and methods for welding would also be suitable, as o well as other known methods for providing a sealed joint between two pieces of material. To minimise the chance of any major air leakages, the pieces of fabric should be as large as is feasible or available, thereby reducing the number of welds required.

An air inlet 110 communicates with the cavity and is connected in use to a 15 pressure controlled fan or pump for inflating the body 101. The fan/pump will typically S be configured to automatically reinflate the body 101 when the pressure drops below a set level as a result of air permeating through the fabric of the preferred embodiment and/or any leakages. If preferred, the upper sheet 102 could be made from an air impermeable fabric to help minimise pressure loss in the body and the consequent need to reinflate. The preferred pressure will be determined to suit the particular configuration of the body 101. The flow of air into the cavity separating the upper and lower sheets 102, 103 will prevent the upper sheet from contacting the ground surface and allowing water to seep therethrough, and will also avoid a large weight of cover and pooled water from bearing down on the ground surface to damage the same.

Means are provided for securing the body to the track surface, typically prior to inflating the body. As the body is sealed, the body need not be secured to the ground along the entire length of each edge 104-107, but will typically be secured to the ground at the corners of the body and at intervals along at least the longitudinal edges 104, 105.

Here eyelets 114 are provided around the edges of the body (external of the cavity), [N:\LIBLL]01848:GJG:TCW jZlli_ ^~Xli_ i through which eyelets elongate securing elements such as soil anchors or stakes can be screwed or hammered into the ground. The soil anchors/stakes can readily be removed after use to allow the cover 100 to be folded rolled up when not in use.

The body, when secured to the ground and inflated, will have a cross section defined by a generally flat lower sheet 102 and convexly curved upper sheet 102 as depicted in Figure 2. For a cover measuring 15 m in width, the body will typically inflate to a maximum height in the centre of the upper sheet 102 of approximately cm. Any rain falling on the cover 100 will run down the convex surface of the ooi upper sheet 102 toward the longitudinal edges 104, 105 of the body 101. As some race tracks have a gutter formed along the inner rail of the track, the cover 100 can be positioned such that water running off the upper sheet 102 and over the edge 104 will pass directly into the gutter. The convex shape of the upper sheet of the inflated upper sheet 102 also enables any wind to pass freely over the top of the cover 100 without S"significant forces acting to dislodge the cover from its secured position.

15 For water running off the upper sheet 102 toward the opposing edge 105, a gutter 111 is typically provided along the edge 105, integrally formed with the body 101. Here the gutter 111 is formed by an elongate inflatable lip 112 which runs along the length of the edge 105 and defines a channel 113 at a junction between the lip 112 and the body 101 at the edge 105. Water running off the upper sheet 102 toward the edge 105 will thus gather in the channel 113 and can be drained off at its ends and/or part way along its length. Here the lip 112 is formed by an overhanging portion of the upper sheet 102 which extends laterally beyond the lower sheet 103 and is folded over itself to form an inflatable tube. For racecourses which are not provided with a suitable gutter along the inside rail, a gutter 111 could be formed along both longitudinal edges 104, 105.

Whilst the cover 100 depicted has straight longitudinal edges 104, 105 and is thus suited to covering straight sections of track, construction of a cover 100 with curved longitudinal edges will allow covering of the bends in the race track. Several covers of varying configuration will normally be required to cover the entire track. If [N:\LIBLL]01848:GJG:TCW required, gutters could be provided along the end edges 106, 107 between adjacent covers. The covers can be configured to span the entire width of the track, however, depending on conditions, it may be more feasible to merely cover the inner half of the track toward the inner rail which will be subjected to the most wear.

In an alternate embodiment, a plurality of apertures 213 may be provided in the lower sheet 203, as depicted in Figure 3, to increase the airflow from the cavity through the lower sheet 203 to aerate the grass. Here the lower sheet 203 is actually formed of strips 214 of fabric arranged in a lattice type arrangement leaving the apertures 213 9 therebetween. This arrangement results in the apertures 213 constituting approximately 45% of the surface area of the lower sheet. The pressure on the remaining space covered by the strips 214 is minimal as the strips act primarily as a structural support and are not subjected to any significant downward pressure. The larger the total aperture area, the greater will be the need to keep inflating the body, and the greater I9 SI will be the aeration of the grass. The lower sheet 203 should preferably be continuous 15 around its periphery to minimise direct leakage of air at the periphery. If apertures are being employed, a total aperture area of 30% to 60% of the total lower sheet area would be appropriate. The material of the lower sheet need not necessarily be air permeable if such apertures are provided. Rather than forming the lower sheet 203 from a lattice of strips, a single continuous sheet could be used with apertures cut therefrom.

Whilst the above description is directed primarily to a cover for covering race tracks, changes to the length and width of the body as required will make the cover suitable for use to cover other sporting fields such as cricket pitches, tennis courts and football fields to protect the same from inclement weather. The cover is also envisaged to be of use in covering grounds prior to outdoor events.

[N:\LIBLL]01848:GJG:TCW

Claims (19)

1. An inflatable ground cover comprising: a body formed of an upper sheet of flexible, light transmissive substantially water impermeable material and a lower sheet of flexible, light transmissive material, said upper and lower sheets being sealingly secured around edges thereof to form a cavity therebetween, an air inlet communicating with said cavity for inflating said body, and means for securing said body to a ground surface, wherein said lower sheet is adapted to enable air to pass from said cavity 10 through said lower sheet to a ground surface therebeneath.

The inflatable ground cover of claim 1, wherein said lower sheet material is air permeable.

3. The inflatable ground cover of either of claims 1 and 2, wherein said lower sheet is provided with a plurality of apertures for passage of said air from said cavity to said ground surface therebeneath.

4. The inflatable ground cover of claim 3, wherein said lower sheet is formed as a lattice of strips forming said apertures therebetween.

The inflatable ground cover of either of claims 3 and 4, wherein said apertures constitute between 30% and 60% of the surface area of said lower sheet.

6. The inflatable ground cover of any one of claims 1 to 5, wherein said upper and lower sheet materials have a light transmissivity of at least

7. The inflatable ground cover of any one of claims 1 to 6, wherein said upper and lower sheet materials have a UV factor of less than

8. The inflatable ground cover of any one of claims 1 to 7, wherein said upper and lower sheet materials have a mass of less than 300 grams per square metre.

9. The inflatable ground cover of any one of claims 1 to 8, wherein said upper and lower sheet materials are a fabric.

The inflatable ground cover of claim 9, wherein said upper and lower sheet materials are a polypropylene fabric. [N:\LIBLL]01848:GJG:TCW

11. The inflatable ground cover of any one of claims 1 to 10, wherein said means for securing said body to a ground surface comprises a plurality of eyelets each for receiving an elongate securing element.

12. The inflatable ground cover of any one of claims 1 to 11, wherein a gutter is provided along an edge of said body.

13. The inflatable ground cover of claim 12, wherein said gutter is formed by an elongate inflatable lip defining a channel at a junction between said lip and said body at said edge. So

14. The inflatable ground cover of any one of claims 1 to 13, wherein said 10 body is configured to cover a section of race track.

15. An inflatable ground cover comprising: *o°a body formed of an upper sheet of flexible, substantially water impermeable material and a lower sheet of flexible material, said upper and lower sheets being sealingly secured around edges thereof to form a cavity therebetween, 15 an air inlet communicating with said cavity for inflating said body, S means for securing said body to a ground surface, and a gutter provided along an edge of said body.

16. The inflatable ground cover of claim 15, wherein said gutter is formed by an elongate inflatable lip defining a channel at a junction between said lip and said body at said edge.

17. The inflatable ground cover of either of claims 15 and 16, wherein said material is light transmissive. [N:\LIBLL]01848:GJG:TCW

18. A method of covering a race track or sports field surface with the inflatable ground cover of any one of claims 1 to 17, said method comprising the steps of: laying said inflatable ground cover over said surface, securing said inflatable ground cover to said surface, and inflating said body via said air inlet.

19. An inflatable ground cover, substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 of the accompanying drawings. 999* DATED this Seventh Day of July 1999 Freeform Fabric Structures Pty Ltd Patent Attorneys for the Applicant SPRUSON FERGUSON 99 *9OO [N:\LIBLL]01848:GJG:TCW