WO1989009306A1 - Tracks for equestrian use - Google Patents

Abstract

An all-weather synthetic surface or track for equestrian use comprises elastomeric granules bonded together to form a coherent resilient and yet rapidly water-draining and porous body (14). Above this body is provided a layer of loose elastomeric granules (12) which synergistically interact with the coherent resilient body (14) to simulate a grass/turf combination. Below the coherent body (14) is provided a rapidly-draining base of washed limestone chippings (16, 18), or equivalent material, separated therefrom by a layer of open-textured tarmac (22), with a one-way membrane (24) between the limestone (16, 18) and the ground (20) on which the track is laid.

Description

TRACKS FOR EQUESTRIAN USE

This invention relates to tracks or synthetic surfaces for equestrian use.

Synthetic surfaces or tracks for equestrian use have been proposed in a variety of forms to meet the considerable need for such surfaces. Some of these proposals have included the use of elastomer ic materials and others involve mixtures of sand and lubricating oils. However, all such proposals known to the Applicants have been subject to significant shortco ings, including the fact that in winter the track freezes and is thereby rendered unsuitable for use, or else the surface requires repeated harrowing and rolling, or otherwise makes excessive maintenance requirements, or both. Moreover, previous proposals often provide too much "give" allowing the hoof of a horse to move forward after initial impact, which can lead to joint and shin problems. Other shortcomings include a tendency to produce dust and particulate matter which can be inhaled by a horse or may adhere to its coat.

In US 3,272,098 there is disclosed a track for equestrian use as defined in the pre-characterising portion of claim 1 hereof. In this prior publication there is disclosed a track in the form of a paving material and paving surfacing for use in the construction of race tracks for horses. A self -hardening screedable fluid paving material is disclosed which hardens to a tough all-weather rubbery urethane pavement. However, although such a material may have certain uses it does not meet present day requirements for horse racing tracks and gallops, and these shortcomings are even more marked in relation to a synthetic track incorporating jumps for the horses. Thus, for example, we have found that a material as disclosed in this prior specification falls short of requirements in terms of simulating the dynamic performance of natural turf at the instant of hoof take-off and landing. Though the material cushions, it produces too rapid deceleration as compared with natural turf, which permits a critical degree of hoof slip. It has been stated that when a horse is running, each hoof goes into the track with its bottom flat. There is generally little rotation. The hoof slides downward and forward, and then it stops. The track surface must slow and stop the hoof with uniform and minimum deceleration. Moreover, there is a considerable doubt that the material disclosed in the US patent would escape freezing under winter conditions.

In short, previous proposals in relation to tracks for equestrian use have not provided a satisfactory combination of weather resistance and provision of satisfactory dynamic characteristics for equestrian use, and an object of the present invention is to provide a track for equestrian use offering improvements in relation to one or more of the matters discussed above, or generally.

According to the invention there is provided a track for equestrian use, as defined in the accompanying claims.

In an embodiment described below a track providing a synthetic surface for equestrian use comprises a discrete upper layer having an appreciable layer depth of loose and unbonded elastomeric granules. Below this layer is provided a layer in the form of a coherent body comprising elastomeric granules bonded together. The coherent body thus formed is completely porous to water and very rapidly draining. The bonding means does not form an impervious or partially impervious layer as is the case with synthetic tracks for equestrian use as previously proposed.

In a preferred embodiment, the coherent granular body is very rapidly self-draining and is capable of draining 75 per cent, preferably 90 per cent, of its own volume of water in 20 seconds, and preferably in 10 seconds, whereby water does not stay long enough in contact with it to solidify in its interstices. Moreover, ice formation is inhibited by the thermal insulation effect of the elastomeric material and any ice film that does form around the granules is readily broken by hoof impact.

Below the coherent resilient body is provided a rapidly draining zone, for example, of limestone chippings or like rapidly draining material. The limestone chippings are provided in two discrete layers. The chippings in these layers are of different particle sizes. A layer of open-textured tarmac separates the limestone from the coherent resilient body. A one-way membrane separates the limestone from the land on which it is laid.

In the preferred embodiment, the layer of loose and unbonded elastomeric granules provide extra resilience for the synthetic track, over and above those of the coherent resilent body. Moreover, due to their unbonded condition, a degree of slip or slide is permitted between the particles. As a result, the loose layer simulates the presence of grass on turf, while the coherent resilient body corresponds to the firm turf base present below the grass in natural turf. The combination of loose and bonded granules provides the necessary resilient characteristics, avoiding bottoming even under jumping loads, while retaining the limited slip characteristics provided by natural turf and which are so important to the simulation of same by an artificial material.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

Fig 1 shows a vertical section through a track for equestrian use; and

Fig 2 shows a perspective view of a coherent resilient body and associated upper layer of loose elastomeric granules which provide the upper two layers in the track of Fig 1.

As shown in the drawings, a track 10 for equestrian use comprises an upper layer 12 of loose and elastomeric granules. Below layer 12 there is provided a layer 14 in •the form of a coherent resilient and porous (water permeable) elastomeric body. Below the layer 14 there are provided two layers 16 and 18 of washed limestone. The latter layer is provided above an area 20 of properly drained land. A layer of textured tarmac or bitumastic emulsion 22 (such as eolac brand - trade mark) , is provided between the upper chalk layer and the coherent resilient body 14. A one-way membrane 24 is provided between limestone layer 18 and the land 20.

The preparation of a track for equestrian use 10 in accordance with the invention is carried out as follows. First, the land 20 is dug out and suitable drains are provided to tak.e away surface moisture and rain.

Then, the one-way membrane 24 is laid upon the drained land. Such a membrane provides a one-way draining action. A suitable membrane is available under the trade mark Tera from Imperial Chemical Industries.

Above the membrane 24 is provided a layer of washed limestone particles or chippings. This layer may be of depth 1 to 6 inches, and preferably about 3 inches, the particle sizes being in the range 1 to 6 inches. Above limestone layer 18 there is provided a second limestone layer 16 of washed particles, the particle sizes being somewhat smaller than those of the layer 18 and the depth of the layer 16 being from 1 to 4 inches.

The layers 16 and 18 provide a solid and self-draining base for the track 10, the draining action being enhanced by the one-way action of membrane 24.

Above the upper limestone layer 16 there is provided a layer 22 of textured tarmac. This layer is of thickness 1.57 to 2.36 inches (40 to 60 millimetres), and comprises a conventional tarmac base material having mixed therewith an aggregate material of small stones or chippings in an amount such that the stones or chippings are coated but do not form a continuous tarmac layer. The openings between the particles provide porosity.

The layer 14, which is in the form of a coherent porous elastomeric body, comprises granules of pure natural or synthetic rubber. In this embodiment, these particles are of SBR (synthetic butyl rubber) available in the UK from Rushden Granulation Limited under the code 2060. These granules have a mean particle size from 0.075 to 1.0 inches (1.91 to 25.4 millimetres), and preferably 0.125 to 0.5 inches (3.18 to 12.7 millimetres). The particular preferred mean size is 0.25 inches (6.35 millimetres).

The depth of layer 14 may be from 0.5 to 6.0 inches (12.7 to 152.4 millimetres) and preferably 0.75 to 3.0 inches (19.05 to 76.2 millimetres).

The elastomeric granules may be obtained from shredded tyre treads or other shredded rubber goods. Preferably, the elastomeric granules should have somewhat flat side faces. Individual particles are of irregular angular shape. The flat side faces enhance inter-granule bonding.

The bonding means for forming the granules into the coherent resilient body may comprise a urethane elastomer, or other suitable bonding agent capable of providing the required coherent nature of the body in combination with the indicated porosity, without compromising the requirement for resilience.

With regard to resilience, it should be noted that the layers 12 and 14 together provide a surface for hoof impact which retains its inherent resilience, without bottoming, at loads of up to 12 tons per square inch, as often arise during equestrian use of the kind concerned.

For the purpose of laying the layer 14, the elastomeric granules are placed in a rotary mixer and to them is added the bonding agent in the ratio (by volume) of ten parts of the granules to one part of bonding agent. This ratio may be varied from, for example, 5 to 20 to one, according to the bonding agent employed, subject always to the requirement for adequate porosity, as defined. The bonding agent employed in this embodiment is -Desmodur code 0307 available from Bayer AG. This material is mixed with the granules until the rubber granules are thoroughly coated. The coated granules can then be applied to the layer of textured tarmac. They are raked out to form a layer of thickness from 0.75 to 6.0 inches (19.05 to 152.44 millimetres), preferably about 2.5 inches (63.50 millimetres) , which is then rolled flat by means of a roller of weight about 0.75 tons so that the layer 14 then has a thickness of approximately 1.25 inches (31.75 millimetres). The bonding agent sets in approximately 2 hours. It is to be noted that the granules employed in layers 12 and 14 are cut with flat surfaces. In layer 14 this assists in the bonding process. In layer 12 the loose granules permit a degree of relative inter-granular bodily movement under the action of hooves thereon. The generally flat surfaces of the granules and their somewhat angular profiles inhibits an unduly free rolling action of the granules while permitting the necessary slide/slipping characteristics which simulate the action of grass in natural turf.

The layer 12 of loose elastomeric granules is then laid on top of layer 14. These granules are of the same material as for layer 14 and preferably have a particle size of from 1 to 10 mm, the preferred range being 2 to 6 mm. Tests have shown that particle sizes above and below this range lead to kicking up of the material during use. The thickness of layer 12 may be from 0.5 to 6.0 inches (12.7 to 152.4 millimetres), and preferably from 1.5 to 3.5 inches (38.1 to 88.9 millimetres).

In use, the track 10 may be provided in a rectangular area surrounding jumps for equestrian use, or could be provided as a continuous track or surface for equestrian use, for example in gallops.

Interestingly, the track 10 provides significant advantages. The coherent body 14 ensures that there is a firm yet resilient base to the track. Due to the porous nature of the body 14, it is self-draining, and this characteristic is supported and enhanced by the washed limestone base. Thus the track itself does not freeze. This characteristic arises in part from the method of bonding the particles and the proportion of bonding agent, which may be from 1 to 20 to 1 to 5 parts of the rubber granules, by volume. The loose rubber granules of the upper layer 12 provide a surface which gives the acceptable feel for horses comparable to that of grass on turf. This surface may be appropriately coloured, for example green. Due to adoption of the defined particle size for the granules in the upper layer, the tendency for such materials to fly up is minimised.

Modifications which could be made in the above embodiment while remaining within the scope of the invention include the use of alternative bonding agents to producethe coherent resilient and porous elastomeric body, and the use of alternative specific types of natural or synthetic elastomer for the elastomeric granules.

Claims

1 A track for equestrian use comprising:

a) a base layer to be laid on the land where the track is required;

b) an elastomeric layer laid on said base and comprising granules of an elastomer together with bonding means for said granules to form a coherent resilient body therefrom;

c) said elastomeric layer providing a resilient cushion for hooves during such equestrian use;

characterised in that

d) said elastomeric layer further comprises a layer of loose elastomeric granules forming a surface layer above said coherent resilient body, said loose granules being substantially unbonded to said coherent resilient body, said loose granules permitting a degree of relative inter- granule bodily movement under the action of hooves thereon.

2 A track for equestrian use having an underlayer comprising a coherent resilient body, characterised by an upper layer comprising loose elastomeric granules.

3 A track according to claim 1 or claim 2 characterised in that said loose elastomeric granules are of a mean size from 1 to 10 millimetres (0.04 to 0.4 inches).

4 A track according to claim 3 characterised in that said loose granules are of a mean size from 2 to 6 millimetres (0.08 to 0.24 inches). 5 A track according to any one of the preceding claims characterised in that said coherent resilient body comprises bonded elastomeric granules of a mean size from 1.91 to 25.4 millimetres (0.075 to 1.0 inches).

6 A track according to any one of the preceding claims characterised by said loose granules comprising a layer of thickness from 12.7 to 152.4 millimetres ( 0 ; 5 to 6.0 inches) .

7 A track according to claim 6 characterised in that said loose granules form a layer of thickness from 38.1 to 88.9 millimetres (1.5 to 3.5 inches).

8 A track according to any one of the preceding claims characte ised in that said coherent resilient body comprises said elastomeric granules bonded by said bonding means, said bonding means being provided in an amount such that in the unstressed condition of the coherent resilient body there are inter-granular openings or spaces through which water can pass, whereby said body is porous.

9 A track according to claim 8 characterised in that the porosity of said coherent resilient body is such that it can drain at least 75 per cent, and preferably 90 per cent, of its own volume of water in 20 seconds, and preferably in

10 seconds.

10 A track according to any one of the preceding claims characterised in that said base layer to be laid on the land where the track is required, is itself porous to water.

11 A track according to claim 10 characterised in that said base layer comprises washed limestone. 12 A track according to claim 10 or claim 11 characte ised in that there is provided a coherent layer of a water-permeable material above said base layer and below said coherent resilient body.

13 A track for equestrian use comprising:

a) a base layer to be laid on the land where the track is required;

b) an elastomeric layer laid on said base and comprising granules of an elastomer together with bonding means for said granules to form a coherent resilient body therefrom;

c) said elastomeric layer providing a resilient cushion for hooves during such equestrian use;

characterised by

d) said coherent resilient body comprising said elastomeric granules bonded by said bonding means, said bonding means being provided in an amount such that, in the unstressed condition of the coherent resilient body, there are inter-granular openings or spaces through which water can pass, whereby said coherent resilient body is porous.