EP0683836B2 - Synthetic tennis surface element and method for producing same - Google Patents

Abstract

The present invention relates to an element suitable for constructing permanent tennis courts and for repairing old tennis courts of the blaize (dirt) type, characterised in that it comprises a structured textile backing (1) forming a carpet having an open structure and composed of non-rotting synthetic fibres (4), which is successively filled with a first layer (6 and 7) essentially consisting of sand having a particle size ensuring suitable drainage and with a second, surface, layer (8) consisting of ground brick having a smaller particle size than the particle size of the underlying layer. <IMAGE>

Description

The present invention relates to an element allowing the production of a synthetic tennis court similar to clay courts (crushed bricks) allowing more particularly the practice of outdoor tennis.

The invention also extends to a method of producing such terrain.

The invention relates in practice to the construction of permanent clay tennis courts and to the rehabilitation of old tennis courts, in particular tennis courts made of porous concrete or any other hard surface.

Currently, the construction of a so-called "clay" tennis surface involves the installation of at least three successive layers of constituent elements.

First of all, it is necessary to have a foundation layer which will constitute the solid base of the system capable of supporting loads and which has the required quality of flatness. It is most generally of compacted grave.

The second layer consists of a layer of limestone or a layer of equivalent material and which is provided in particular to ensure good drainage, as well as for flexibility of play.

Finally, a red covering layer is produced, which is generally obtained from finely pulverized crushed brick.

Then, the drawing of the lines of play is generally carried out with painting or by installation of prefabricated plastic lines.

This type of surface called "clay" has become traditional for the practice of outdoor tennis.

The major interest of a surface of this type is the comfort of play which protects the muscles and the joints of the player. This comfort results on the one hand from the flexibility in depth which makes it possible to absorb the vertical impact of the foot during the race and on the other hand, from the controlled slip of the tennis shoe on the surface, which prevents the blocking of the foot in its horizontal movements.

However, this classic construction of clay playing surfaces has two fundamental drawbacks:

First of all, in the event of frost, the water which is suspended in the intermediate layer (generally a limestone layer) freezes and causes the limestone / clay complex to swell. During the thaw, the whole collapses, losing all cohesion and the lines of play are destroyed. As a result, the surface is unusable and requires repair which can only be undertaken when the risk of freezing is eliminated. This results in several months of neutralization of the ground.

Another drawback is observed in the event of heavy rain, when the limestone / clay complex no longer ensures sufficiently rapid drainage. Indeed, this surface is greatly weakened when it is too wet and this necessarily results in a waiting time before being able to reuse it after heavy rain.

It is known to produce "synthetic turf" intended for football, hockey or tennis fields and which consist in particular of tufted or needled products.

Several documents, and in particular documents EP-A-263566, US-A-4044179, US-A-4396653 and DE-A-3703866, describe examples of execution of such synthetic turf. In all these documents, it is proposed to add one or more layers of sand in order to improve the properties in particular of rebound of these synthetic turf. In most documents, it is proposed to successively arrange in the tufted product two layers of sand of different particle size.

Document DE-A-3204215 describes a synthetic turf loaded with layers of sand, the particle size of which decreases from bottom to top. This document also mentions the use of non-angular sand grain shapes.

In document WO-A-8909306, it is proposed to add granules of elastomeric materials in products of this type in order both to improve the draining properties and to avoid the formation of ice.

In general, all of these coatings allow some of the elements constituting the tuft or the needlework to remain in the air (bristles, strips, etc.).

Furthermore, document EP-A-0 373 282 describes an element for the construction of permanent tennis courts of the clay type and for the rehabilitation of old tennis courts of the clay type comprising a structured textile support with an open structure. and composed of a base and fibers into which are successively loaded a first layer of sand and a second surface layer consisting of crushed brick.

The present invention aims to offer in particular an element suitable for both the construction of permanent clay tennis courts as well as for the rehabilitation of such tennis courts, even on a concrete support or on any hard surface, and which avoids the disadvantages notably mentioned due to frost and heavy rain.

The invention also aims to provide a product with the same playing comfort as traditional products.

Finally, the solution proposed by the invention also makes it possible in the long term to avoid the significant costs, linked to the renovation or the restoration which is necessary with conventional grounds, as regards both the support surface and the game lines.

The present invention relates to an element according to claim 1.

Preferably, the height of the second crushed brick layer is between 1/5 and 1/10 of the total height of the complex comprising the two layers of sand and crushed brick.

The height of the textile fibers constituting the open structure carpet is advantageously between 18 and 25 mm, preferably between 20 and 23 mm in order to ensure sufficient vertical stability for the complex. The textile fibers are preferably made of polypropylene.

Advantageously, use is made of a loose structure tuft associated with the perforated base which preferably consists of a canvas support impregnated with a layer of latex.

The present invention also relates to a method according to claim 6.

In practice, a carpet of this type is laid on an adequate bottom structure, for example a compacted grave, but also in the case of a restoration of a concrete tennis court, on a conventional concrete base, preferably superficially flattened and regenerated.

A first layer, essentially of sand, is loaded into the textile support to a height such that a vacuum of the order of 3 mm is left relative to the upper surface of the carpet.

According to a preferred embodiment, a tuft 23 mm high, for example, is loaded with a first sub-layer of sand having a particle size of 0.2 / 0.8 mm over a height of approximately 15 mm and a second sand sub-layer having a particle size of 0.2 / 0.3 mm over a height of approximately 5 mm.

The particle size of the first sand sub-layer is chosen so as to ensure both good penetration into the mat and its complete permeability, while the particle size of the second sub-layer is chosen so that it can serve as a base for the subsequent layer of crushed brick.

The crushed brick layer is then placed over a height of approximately 3 mm so as to fill the void remaining on the surface of the textile support.

After the completion of this surface, the assembly is compacted by the means usually used for the preparation of clay tennis courts.

The use of the traditional surface material constituted by crushed brick makes it possible to obtain a non-freezing complex having the characteristics of flexibility comparable to traditional products.

It should be noted that the profile, that is to say the surface appearance of the sand used, is selected to avoid damaging the textile fibers of the carpet. Non-angular shapes both prevent this deterioration while ensuring excellent permeability.

This permeability is further enhanced by the existence of holes drilled in sufficient quantity in the base of the latex-coated textile support.

The use of additional draining structures arranged below the product of the invention naturally also falls within the scope of the present invention.

It should be noted that in addition to its qualities of flexibility and slipperiness, the carpet / sand / clay complex can immediately absorb a significant amount of water while waiting for it to infiltrate the foundation layer. Thus, the layer will be quickly removed from standing water and the time of immobilization of the ground after a downpour will be reduced.

The rebound qualities of the ball are equivalent to those obtained on traditional clay courts.

The present invention also offers considerable advantages for the restoration of old tennis courts made of porous concrete and of all hard surfaces on which the product according to the invention can be used after restoration (planing, leveling and drilling ) in order to achieve permeabilization of the surface of this foundation layer.

It thus becomes possible to transform hard worn and expired surfaces into flexible clay surfaces.

The present invention will be described using a particular embodiment which is shown in the single accompanying figure.

This figure represents a textile support bearing the general reference 1 consisting of a base comprising a canvas support 3 impregnated with a layer of latex 2 in which are fixed by conventional fiber tufting techniques 4 made of polypropylene and having a height about 25 mm, and in a relatively loose structure.

The base of the textile support is pierced with openings 5 in order to present adequate drainage.

This textile support 1, after having been placed on a flat surface, is loaded with a first sand sublayer 6 having a particle size of 0.2 / 0.8 mm over a height of 15 mm and then a second under layer of sand 7 having a smaller particle size 0.2 / 0.3 mm over a height of 5 mm.

Finally the last millimeters are filled with crushed brick 8.

Preferably, a carpet will be chosen whose fibers are "clay" color so as to blend with the crushed brick.

The ball rebound qualities are equivalent to those obtained on traditional tennis courts.

Regarding the design of the game lines two possibilities can be envisaged for products according to the present invention.

On the one hand, it is possible to prepare lines in white carpet which will be encrusted according to the official routes before the installation of the sand in the carpets. These lines will be made using a textile structure much tighter and slightly higher than the adjacent carpet serving as a textile support in order to move the general level of the lines by a few millimeters when the whole is covered with clay.

Another possibility is to prepare lines in plastic profile and arrange them on the locations of the official routes. These plastic profiles have the appearance of tubes having a rectangular section of 50 x 23 mm and are glued to the textile support before the sand is placed.

Claims (10)

1. Element for the construction of permanent clay tennis courts and for the reconditioning of old clay tennis courts, including a structured textile support (1) forming an open-structured carpet and composed of a base (2, 3) and of rotproof synthetic fibres (4) into which have been successively filled a first layer (6 and 7), essentially consisting of sand and having a particle size which ensures a suitable drainage, and a second surface layer (8) consisting of crushed brick, characterized in that the particle size of the crushed-brick layer is less than that of the underlying sand layer, the particle size of this latter ensuring a suitable drainage, in that the sand used in said first layer (6 and 7) has non-angular grains and in that the base (2, 3) is pierced with holes (5) in order to further heighten the permeability.
2. Element according to Claim 1, characterized in that the second layer has a height between 1/5 and 1/10 of the total height.
3. Element according to Claim 1 or 2, characterized in that the first layer essentially consisting of sand is composed of two underlayers with a particle size of respectively 0,2/0,8mm (6) and 0,2/0,3mm (7).
4. Element according to any of the preceding claims, characterized in that the textile support consists of a loose-structured tufted product.
5. Element according to Claim 4, characterized in that the height of the textile fibres (4) constituting the open-structured carpet (1) lies between 18 and 25mm and preferably between 20 and 23mm.
6. Method for producing new permanent clay tennis courts and for reconditioning old clay tennis courts, characterized in that a structured textile support (1) forming an open-structured carpet composed of a base (2, 3) and of rotproof synthetic fibres is laid on a plane surface, in that the textile support is successively filled with a first layer (6 and 7) essentially consisting of sand and having a particle size which ensures a suitable drainage, and with a second surface layer (8) consisting of crushed brick with a particle size less than that of the underlying layer, the sand used in said first layer (6 and 7) having non-angular grains and the base (2, 3) of the textile support (1) being pierced with holes (5) in order to further heighten the permeability.
7. Process according to Claim 6, characterized in that the step in which the layer essentially consisting of sand is filled, is broken down into two steps in which a first underlayer (6) consisting of sand and having a particle size of 0,2/0,8mm is filled, and a second underlayer (7) consisting of sand and having a particle size of 0,2/0,3mm is filled.
8. Process according to Claim 6 or 7, characterized in that the plane surface is obtained by compacting earth or gravel in the case of a new construction of permanent clay tennis courts.
9. Process according to Claim 6 or 7, characterized in that the plane surface is obtained by levelling, surface finishing and piercing a concrete base in the case of reconditioning old tennis courts.
10. Use of an element according to any of the claims 1 to 5 for obtaining permanent clay tennis courts.