EP0358209B1 - Tennis court surfacing - Google Patents

Description

The invention relates to a tennis court covering according to the preamble of claim 1.

The classic tennis court, which consists of broken brick, is still considered by most tennis players because of its elastic properties and its non-slip properties for the player. However, it has the disadvantage that it requires very intensive care and has to be prepared practically every year. This is extremely costly, especially with today's masses of players, so that new solutions were sought which, on the one hand, have the properties of the brick flour tennis court, but on the other hand require as little maintenance as possible.

For example, a sports field is known in which an elastic plastic layer is applied to a solid surface and solidified by means of an adhesive. After peeling off this elastic layer, a color layer (red or green) is then applied in order to visually improve the black rubber particles of the elastic layer, which are usually colored with carbon black.

A tennis court produced in this way is easy to maintain, but has the disadvantages that it is not slip-friendly, ie it becomes smooth after some time and also has an irregular and too elastic ball bounce behavior. The latter behavior is partly due to bumps in the elastic surface, but also partly due to the elastic particles that act directly on the ball.

In order to improve the slip behavior of such a tennis court, it has been proposed according to DE-A-28 26 206 to provide the non-sliding surface of the rubber covering with rubber-elastic grains, with smaller, smaller rubber-elastic grains being provided between the grains to fill up the spaces.

Such a place is also easy to maintain, but again has the disadvantage that the loosely sprinkled particles have an abrasive effect on the fixed particles. As a result, such a covering becomes smooth after some time and has to be removed again.

Another covering is known from DE-A 32 31 231. In addition to the ease of maintenance already mentioned, such a court has a relatively good and long-lasting playability, although it should be noted that such a court is not suitable for tennis tournaments, since it has an unfavorable ball bounce behavior in relation to the conventional brick meal court. This ball bounce behavior is essentially due to the fact that the unevenness in the rubber body layer cannot be compensated to a sufficient degree by the layer of broken brick, ie the thickness of the layer of broken brick is relatively inconsistent. In this respect there is a more or less strong direct contact of the tennis ball with the rubber bodies, which is different due to their elastic properties Bounce behavior of the tennis ball produce than the conventional brick breakage layer.

DE-AS 22 58 566 relates to a floor covering for tennis courts, the lower layer of which consists of an elastic polymeric material (expanded polystyrene), on which an upper open-pore plate layer of a hard mineral (granular fired clay) is applied, which is solidified by a weather-resistant binder and is bound to the lower layer. Soft fired clay powder is sprinkled on this clay layer, the interface area between the hard and soft clay powder should be connected to the soft clay powder via the binder that is present in the hard clay powder.

However, the tennis court covering described here does not meet the desired requirements that are gentle on the musculoskeletal system of the player, since the hard mineral layer is too thick and therefore too inelastic.

The invention is therefore based on the object of providing a tennis court surface which, on the one hand, is easy to maintain and, on the other hand, has practically the same ball bouncing behavior as in a conventional brick meal tennis court.

The problem is solved by the characterizing features of claim 1.

According to the invention, a tennis court covering is provided which has practically the same positive properties as the conventional broken brick flour tennis court, however practically no longer has to be maintained. A tennis court that has been produced according to the method according to the invention only has to be sprinkled in now and then with loose broken brick. Otherwise, it does not need any further care for years. It absorbs all precipitation and, due to its permeability, transfers it to an artificial or natural drainage system provided in the ground, ie it is independent of wind and weather. Even the marking lines can be permanently applied to the sports field surface with plastic paint so that the boundary lines do not have to be renewed over the years.

The covering according to the invention is expediently applied to a solid base layer, which can be of natural or artificial origin. An asphalt or concrete layer, which is expediently water-permeable, is advantageously used as the base layer. This solid surface is of course the size of a playing field.

According to the invention, a granulate made from a first elastic polymeric material is first applied to this solid base, which has previously been mixed with a binder in the not yet cured state. Suitable polymeric materials are rubber-elastic polymeric materials, which include polyolefins, polyurethanes, possibly in a foamed state, and rubber (vulcanized rubber). Of this material, rubber is preferred which has been comminuted in the usual way (grinding and the like). Such rubber materials include not only natural rubbers, but also the artificial rubber components.

It is particularly advantageous to use recycled rubber products, which are produced, for example, by processing rubber waste materials from car tires and the like. or obtained from waste products.

The particle size of the irregularly shaped particles of the first layer can be up to about 4 mm, with about 80% by weight of the particles having a grain size of about 2-4 mm.

The thickness of the first layer, consisting of the rubber-like particles and the binder, is on average about 0.7-1.5, in particular about 1 cm.

The materials for this first layer are known from DE-A-21 56 255, to which reference is made for the purposes of disclosure.

From the latter publication, a polyurethane-based binder is also known which can be used to solidify this layer, so that reference is also made to this. However, other binders can also be used, for example based on epoxy, polyacrylate or polymethacrylate. If rubber particles are used, the usual vulcanizing agents can also be used. Furthermore, due to their thermoplastic properties, polymeric materials that soften thermally and can be welded can be treated with heat without the addition of any additional binders and thereby bonded to one another. However, a polyurethane-based adhesive is preferably used, as described, for example, in DE-A 21 56 255.

These adhesives are mixed with the particles of the first layer in the pourable state, for example in a weight amount of 1: 4 - 1: 6, in particular about 1: 5 binder / particles. The latter particles are usually applied in an amount of about 7 kg / m² of sports field area.

It is particularly advantageous to use the binder in an amount of 1.4 kg / m².

After the application, the mass is spread out and leveled using customary methods. After the binder has hardened, a second layer, as explained below, can then be applied.

Due to the average grain size and the irregular shape of the particles and the small amount of binder, it is ensured that sufficient voids or gaps remain between the individual particles, which can make up, for example, 20-70% by volume of the material used. Due to this empty volume, rainwater can flow between the particles and be drained from the sports field area through a drainage system underneath.

Likewise, the formation of pressure points is avoided by the outflow.

Due to the elastic properties that are essentially imparted to the covering by this layer, the musculoskeletal system of the players, in particular the joints, is protected.

After this elastic first layer has hardened, a layer of relatively hard mineral material (sand), in particular quartz sand or clinker powder, is applied as the first leveling layer, which layer is solidified with a further binder. This second binder is the same or different from the first binder, advantageously the same. The use of polyurethane is also particularly preferred here.

According to the invention, about 1-3, advantageously about 2 kg of sand per m² of covering are applied to the elastic first covering. The grain size of the sand is up to 2 mm, preferably about 80-90% by weight of the sand having a grain size of about 1-2 mm. The grain shape should preferably be angular, so that the next finer layer gets better hold.

The sand is mixed with the liquid, subsequently curing binder, preferably polyurethane, before application, the weight mixing ratio of sand / binder being about 30: 1 to 3: 1, in particular about 10: 1.

It is particularly advantageous to use polyurethane in an amount of about 0.1-0.5, in particular about 0.3 kg / m² of sand surface.

This sand / binder mixture is also spread out in the usual way as a layer which is then leveled out. The sand fills the surface unevenness, which is due to the different size and irregular shape of the rubber-like particles.

After hardening, the sand layer has a thickness of about 1-1.5 mm on average over the elastic layer and is essentially completely flat. "On average" means that somewhat larger layer thicknesses can occur due to the unevenness of the elastic layer to be filled. The thickness ratio between the elastic layer (first layer) and the hard mineral layer (second layer) is in a range from 4: 1 to 10: 1.

Due to the leveling of the surface on the one hand and the relatively inelastic, hard properties of the sand on the other hand, excellent ball bounce behavior is ensured, i.e. the ball does not jump irregularly to the side as a result of surface unevenness and does not jump as strongly as would be the case if it hit the rubber-elastic grains directly. As a result, the hard layer of sand exerts a certain damping effect on the ball that bounces, which essentially equates to the bouncing behavior at the clay court.

However, a sand covering produced in this way is not yet suitable for use as it does not slip due to its abrasive properties and also presents an increased risk of injury to the players.

In order to eliminate the latter disadvantages and to further improve the ball bounce behavior and the slip ability of the covering, a third layer is applied as a second leveling layer, which consists of broken brick flour, to which a further binder has been added. This binder is advantageously identical to the two binders used above.

The broken brick flour has a grain size of up to 1 mm, advantageously about 80% having a grain size of about 0.5-1 mm.

According to the invention, about 1-3, preferably 2 kg of broken brick flour / m² of sports field area are applied. Before that, the broken brick flour is advantageously used with liquid polyurethane in the same amounts as for the sand layer, i.e. about 0.3 kg PUR / m² sports field area is used according to the preferred embodiment.

After leveling and drying, this layer adheres to the spaces between the individual grains of sand and is therefore difficult to rub off. On the other hand, due to the relatively small amount of binding agent used, the adhesion of the broken brick particles, which are softer in relation to the sand, is not so strong that this covering would behave like an emery.

A surface produced in this way has practically the same playing characteristics as a conventional tennis court based on broken brick, i.e. it is suitable for tournament games and is also extremely easy to maintain.

As already mentioned above, the boundary lines are applied to the bound brick flour layer with the aid of firmly adhering white paint, for example based on PUR, which can practically not be removed during play.

In order to improve the slip behavior, loose brick powder is finally applied to the bonded brick powder layer, a liquid binder, such as water and the like, being added to reduce the generation of dust.

A covering produced in this way is water-permeable due to the low binder content in the respective layers and the selected relatively large grain sizes of the individual particles and absorbs the rain water quantities in the shortest possible time - provided that there is a functioning drainage system.

The above covering is manufactured in situ and remains connected to the base covering.

In a further embodiment, however, the sports field covering can be factory-made in the form of plates and the like. are produced by the same method, which are then applied to the base covering, the preformed plate being applied to the base surface with the aid of the binder used above. The binder used can be the same or different from the binder used to produce the individual plate layers. Likewise, the binder can be spread over the entire base surface or the like in the form of strips. be applied to the base surface. It should only be noted that the water permeability between the base surface and the underside of the plate is not impaired by the binder layer. Such a procedure is advantageously used when the plates are to be permanently connected to the substrate.

If, however, the plates are to be designed only for a tournament, this plate is fastened to the subsurface using known connection systems which allow the plates to be removed again, for example double-sided adhesive tapes and the like. Here, only the respective plate is fixed in the edge area on the substrate, which is sufficient for fixing the relatively rigid plate on the substrate.

Such plates can be produced in the usual way in a form in which the individual layers are inserted one after the other and are each cured in the usual way. The latter procedure is explained, for example, in DE-A-21 56 255, to the disclosure of which reference is made.

The only drawing shows a surface for sports fields in perspective, with the front cut.

On the base layer 10, which consists for example of concrete or asphalt, the first polymeric layer 12 made of rubber particles 14 is applied, which are solidified with one another with binder in situ. After curing, the second layer 16 of sand particles 18 is applied, which in turn is solidified with binders. Then the third layer 20 is applied, which contains brick powder particles 22, which are solidified again with binder. Finally, in order to improve the slip behavior, loose brick powder 24 is sprinkled on, which may be kept slippery by a further, non-hardening binder, but is essentially kept dust-free.

Claims (10)

1. Tennis court surfacing comprising a first layer (12) of an elastic polymer material (14), a second layer (16) of hard sand (18) consolidated by a bonding-agent as first equalizing layer as well as a layer (24) of non-consolidated brick powder spread onto the surfacing, characterized in that the ratio of thickness of the first layer (12) to the second layer (16) is in the range of 4:1 - 10:1 and that a second equalizing layer of brick powder consolidated by a bonding agent is applied to the second layer.

2. A surfacing according to claim 1, characterized in that the grain size of the sand (18) is up to 2 mm, 80-90 % of the sand preferably comprising a grain size of about 1-2 mm.

3. A surfacing according to claim 1 or 2, characterized in that the thickness of the sand layer (16) is about 1-1.5 mm.

4. A surfacing according to one of the claims 1-3, characterized in that the first layer (12) comprises as polymer material rubber, polyolefines or polyurethanes, foamed if , necessary, in the form of fine-grained particles (14), preferably recycling-products based on rubber.

5. A surfacing according to claim 4, characterized in that the particles (14) of the first layer (12) have a grain size up to about 4 mm, with preferably 80 % by weight of the particles having a grain size of about 2-4 mm and that the thickness of the first layer is about 0.7-1.5, especially 1 cm.

6. A surfacing according to one of the claims 1-5, characterized in that the brick powderk (22) of the third layer (20) has a grain size up to 1 mm, preferably about 0.5-1 mm (about 80 % by weight of the brick powder).

7. A surfacing according to claim 1 or 6, characterized in that the third layer (20) comprises about 1 to 3, preferably about 2 kg brick powder (22) per m².

8. A surfacing according to one of the claims 1 to 7, characterized in that self-drying curing polymeric adhesives on the basis of polyurethanes, epoxyresins, polyacrylate resins or polymethacrylate resins are provided as bonding-agents for the first (12), second (16) and/or third (20) layer.

9. A surfacing according to one of the claims 1 to 8, characterized in that the bonding agent is provided in an amount of about 0,1-1,6, especially about 1.4 kg per m² rubber layer and about 0.3 kg per m² sand and/or brick powder layer and that the weight-ratio of sand/bonding-agent is about 30:1 to 3:1, preferably about 10:1, with a weight-ratio of bonding agent/particles of the first layer (12) being in a range of 1:4 - 1:6, especially about 1:5.

10. A surfacing according to one of the claims 1-9, characterized in that boundary lines of a drying plastic colour of permanent resilience are applied to the bonded layer (20) of brick powder and that unbonded brick powder (24) is applied to the third layer (20) in an amount of about 1-2 kg per m².

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