GB2132903A

GB2132903A - Improvements in or relating to sports and playing surfaces

Info

Publication number: GB2132903A
Application number: GB08400415A
Authority: GB
Inventors: Colin Havelocke Triffitt Brown; Ralph James Sumner
Original assignee: En Tout Cas PLC
Current assignee: En Tout Cas PLC
Priority date: 1983-01-11
Filing date: 1984-01-09
Publication date: 1984-07-18
Also published as: GB8400415D0; GB2132903B

Abstract

A playing surface comprises a levelled foundation layer (2), an intermediate layer comprising an open mesh fabric mat (4) formed from convoluted stiffly resilient filamentary or strip material intertwined to form a skeletal configuration so as to provide interstices in which are received particles of resilient material (8), and a pile fabric (10) having a flexible backing (12) with an upstanding pile resembling grass in appearance. Preferably the intermediate layer (4) has a backing layer (6) which is porous, but forms a barrier to mud and clay permeating from below. <IMAGE>

Description

SPECIFICATION Improvements in or relating to sports and playing surfaces The invention is concerned with improvement in or relating to sports and playing surfaces.

Because of the disadvantages associated with the maintenance of grassed playing areas, especially those subject to heavy use, several attempts have been made to produce a synthetic playing surface which simulates the appearance of grass, has acceptable resilience characteristics to minimise the risk of injury to players, and aims to reproduce the ball bounce characteristics to which players are accustomed. Many of these attempts have involved the incorporation of a resilient underlay beaneath a mat having a pile surface, but such underlays if sufficiently durable may be unduly expensive and often contribute to abnormal ball bounce characterics and/or give an unacceptable "spongy" feel to the surface, making it difficult for a player safely to judge his movements.

The present invention provides a playing surface comprising a levelled foundation layer an intermediate layer comprising an open mesh fabric mat formed from convoluted stiffly resilient filamentary or strip material intertwined to form a skeletal configuration so as to provide interstices in which are received particles of resilient material, and a pile fabric having a flexible backing with an upstanding pile resembling grass in appearance.

Preferably a top dressing layer of sand or other suitable particulate material is applied in situ to the pile fabric so as to be interspersed between filaments of the pile to a substantially uniform level below that of the free ends of the pile filaments.

In an example of a playing surface to be described, the intermediate layer is provided with a backing layer of porous sheet material, preferably secured to the filaments or strip material of the intermediate layer. It is preferable that the sheet material of the backing layer has characteristics similar to filtration material in order to minimise the amount of mud or clay which might permeate from below.

It has been found in tests carried out on playing surfaces according to the invention that the resilient granules are effectively trapped within the interstices of the open mesh fabric mat and do not migrate, thus avoiding the formation of undesirable depressions at positions of particularly heavy usage.

Moreover, the openness of the construction permits adequate drainage through to the foundation layer.

Suitable materials from which the granules may be formed may include various natural and synthetic rubbers, plastics materials, cork chippings and the like selected for their properties of energy absorbing resilience.

Even with the porous backing provided in the example of the invention, it has been found that the presence of the open mesh fabric mat will to a large extend stabilise the surface of the foundation layer, as any loose material will be trapped by the inter sticesofthe lower surface of the fabric mat since the construction of the latter is open enough to cause deformation of the porous backing to conform at least partially to the contours of said lower surface to create a multiplicity of hollowed-out receses in which loose foundation layer material is held captive.

There will now be described an example of a playing surface according to the invention. It will be understood that the description which is to be read with reference to the drawing, is given by way of example only and not by way of limitation.

The drawing shows a section through a playing surface, including a fragmentary portion thereof to an enlarged scale.

The playing surface depicted in the drawing comprises foundation layer 2 which in the present example is consitituted by crushed rock, but which may have a surface dressing of stone dust or may be any level, reasonably compacted substrate which is free-draining and resistant to disruption by frost.

Laid directly upon the layer 2 is an open mesh fabric mat 4 having deformable backing sheet comprising a porous membrane 6. The mat is formed from stiffly resilient polyamidefilaments having similar characteristics to that of wire, which filaments are intertwined and subjected to heat to form welds where filaments are in contact. The mesh is thus formed into a three-dimensional skeletal configuration such that it will return to its unstressed condition after compression by the action of a footfall. Although the mat 4 is acceptabley durable it may be found that additional stability is achieved by the provision of the porous membrane 6. Received in interstices between the intertwined filaments are granules 8 of rubber.These may, as in the present example, be e.p.d.m. (ethylene propylene diene modified) granules, or where higher "bounce" is required, fragments of tyres will be found suitable.

However it will be understood that any resilient natural or synthetic rubber or plastics material in granular form, solid or foamed, may be found suitable according to the desired "feel" of the playing surface and the degree of hard wear to which it is subjected.

The pile fabric 10, laid upon the layer 4, comprises a woven backing 12 into which are implanted U-shaped lengths of filamentary material 14 so as to simulate the appearance of blades of grass. A top-dressing of fine sand 16 is then applied up to a level 18, that is, below the level of the free ends of the pile 14, so that these free ends protrude from the dressing.

Various modifications may be made within the scope of the invention as defined in the following

claims.

CLAIMS 1. A playing surface comprising a levelled foundation layer, a intermediate layer comprising an open mesh fabric mat formed from convoluted stiffly resilient filamentary or strip material intertwined to form a skeletal configuration so as to provide interstices in which are received particles of resilient material, and a pile fabric having a flexible backing with an upstanding pile resembling grass in appear

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to sports and playing surfaces The invention is concerned with improvement in or relating to sports and playing surfaces. Because of the disadvantages associated with the maintenance of grassed playing areas, especially those subject to heavy use, several attempts have been made to produce a synthetic playing surface which simulates the appearance of grass, has acceptable resilience characteristics to minimise the risk of injury to players, and aims to reproduce the ball bounce characteristics to which players are accustomed. Many of these attempts have involved the incorporation of a resilient underlay beaneath a mat having a pile surface, but such underlays if sufficiently durable may be unduly expensive and often contribute to abnormal ball bounce characterics and/or give an unacceptable "spongy" feel to the surface, making it difficult for a player safely to judge his movements. The present invention provides a playing surface comprising a levelled foundation layer an intermediate layer comprising an open mesh fabric mat formed from convoluted stiffly resilient filamentary or strip material intertwined to form a skeletal configuration so as to provide interstices in which are received particles of resilient material, and a pile fabric having a flexible backing with an upstanding pile resembling grass in appearance. Preferably a top dressing layer of sand or other suitable particulate material is applied in situ to the pile fabric so as to be interspersed between filaments of the pile to a substantially uniform level below that of the free ends of the pile filaments. In an example of a playing surface to be described, the intermediate layer is provided with a backing layer of porous sheet material, preferably secured to the filaments or strip material of the intermediate layer. It is preferable that the sheet material of the backing layer has characteristics similar to filtration material in order to minimise the amount of mud or clay which might permeate from below. It has been found in tests carried out on playing surfaces according to the invention that the resilient granules are effectively trapped within the interstices of the open mesh fabric mat and do not migrate, thus avoiding the formation of undesirable depressions at positions of particularly heavy usage. Moreover, the openness of the construction permits adequate drainage through to the foundation layer. Suitable materials from which the granules may be formed may include various natural and synthetic rubbers, plastics materials, cork chippings and the like selected for their properties of energy absorbing resilience. Even with the porous backing provided in the example of the invention, it has been found that the presence of the open mesh fabric mat will to a large extend stabilise the surface of the foundation layer, as any loose material will be trapped by the inter sticesofthe lower surface of the fabric mat since the construction of the latter is open enough to cause deformation of the porous backing to conform at least partially to the contours of said lower surface to create a multiplicity of hollowed-out receses in which loose foundation layer material is held captive. There will now be described an example of a playing surface according to the invention. It will be understood that the description which is to be read with reference to the drawing, is given by way of example only and not by way of limitation. The drawing shows a section through a playing surface, including a fragmentary portion thereof to an enlarged scale. The playing surface depicted in the drawing comprises foundation layer 2 which in the present example is consitituted by crushed rock, but which may have a surface dressing of stone dust or may be any level, reasonably compacted substrate which is free-draining and resistant to disruption by frost. Laid directly upon the layer 2 is an open mesh fabric mat 4 having deformable backing sheet comprising a porous membrane 6. The mat is formed from stiffly resilient polyamidefilaments having similar characteristics to that of wire, which filaments are intertwined and subjected to heat to form welds where filaments are in contact. The mesh is thus formed into a three-dimensional skeletal configuration such that it will return to its unstressed condition after compression by the action of a footfall. Although the mat 4 is acceptabley durable it may be found that additional stability is achieved by the provision of the porous membrane 6. Received in interstices between the intertwined filaments are granules 8 of rubber.These may, as in the present example, be e.p.d.m. (ethylene propylene diene modified) granules, or where higher "bounce" is required, fragments of tyres will be found suitable. However it will be understood that any resilient natural or synthetic rubber or plastics material in granular form, solid or foamed, may be found suitable according to the desired "feel" of the playing surface and the degree of hard wear to which it is subjected. The pile fabric 10, laid upon the layer 4, comprises a woven backing 12 into which are implanted U-shaped lengths of filamentary material 14 so as to simulate the appearance of blades of grass. A top-dressing of fine sand 16 is then applied up to a level 18, that is, below the level of the free ends of the pile 14, so that these free ends protrude from the dressing. Various modifications may be made within the scope of the invention as defined in the following claims. CLAIMS

1. A playing surface comprising a levelled foundation layer, a intermediate layer comprising an open mesh fabric mat formed from convoluted stiffly resilient filamentary or strip material intertwined to form a skeletal configuration so as to provide interstices in which are received particles of resilient material, and a pile fabric having a flexible backing with an upstanding pile resembling grass in appear ance.

2. A playing surface as claimed in claim 1, wherein the filamentary or strip material is of plastics material heat treated to form welds at points where the filamentary or strip material is in contact.

3. A playing surface as claimed in either one of claims 1 and 2 wherein the intermediate layer is provided with a backing layer of porous sheet material beneath the filaments or strip material of the intermediate layer.

4. A playing surface as claimed in claim 3, wherein the backing layer is secured to the intermediate layer.

5. A playing surface as claimed in either one of claims 3 and 4, wherein the backing layer comprises material which acts as a filtration layer to retain mud or clay.

6. A playing surface as claimed in any of the previous claims, wherein the particles of resilient material are in the form of granules of natural rubber or cork.

7. A playing surface as claimed in any one of claims 1 to 5, wherein the particles of resilient material are in the form of granules of synthetic rubber or plastics material.

8. A playing surface as claimed in any one of the preceding claims wherein a top dressing layer of particulate material is applied in situ to the file fabric so as to be interspersed between filaments of the pile to a substantially uniform level below that of the free ends of the pile filaments.

9. A playing surface as claimed in any one of the preceding claims wherein the foundation layer is a level, compacted free drainage substrate of crushed rock.

10. A playing surface constructed and arranged as hereinbefore described with reference to and as shown in the drawings.