GB2111106A - Synthetic sports surface - Google Patents

Abstract

A synthetic sports surface comprises side-by-side strips of cover layer material (e.g. artificial grass) secured to a base layer, typically of resilient porous material, by means of electrically activatable adhesive tape. If any of the surface covering strips become damaged selected adhesive tapes can be electrically energised to heat and weaken the adhesive bond thereby to permit removal of the damaged strip. The tape is laid on the resilient base layer in a grid formation, the longitudinal tapes being so positioned that they also serve to hold the edges of adjacent cover strips together.

Description

SPECIFICATION Synthetic sports surface This invention relates to a synthetic sports surface and in particular, though not exclusively, to a surface which may provide a large playing area, such as for example that the size of a tennis court or a football pitch.

One common construction of a large area synthetic sports surface comprises a layer of porous synthetic grass material laid over a consolidated porous sub-base, typically comprising a clay and stone mix. Optionally a shock absorbing base layer of apertured rubber sheet material is provided between the synthetic grass material and the sub-base.

In contrast to relatively small playing areas such as selected areas of a cricket pitch, it is not practical to provide a single sheet of synthetic grass material sufficiently large to cover a large playing area such as that of a football pitch or even a tennis court. Instead it is necessary to provide the synthetic grass material in strip form, each strip extending either the length or width of the area to be covered, and the required number of strips being laid side-by-side until the area is covered.

A problem then arises, however, due to the need to adequately secure the individual strips in position to ensure that the playing surface remains smooth and is not prone to localised movement or bagginess. Conventionally this is achieved by the use of long nails inserted through the ends of the strips and located in the sub-base material to maintain the strips under tension. However, said tensioning tends to result in separation of adjacent edges of the successive strips as originally laid, and an unacceptable non-uniformity of smoothness of the resulting playing area. Nails cannot be used to secure the strip edges within the playing area because impact at or near to the nails would tend to cause them to dislodge and present a safety hazard. The established practice is to sew together adjacent strips edges, in situ, but this operation is time consuming and expensive.

The present invention seeks to provide an improved sports surface suitable for a large playing area, and a method for its construction, in which the aforedescribed difficulties are mitigated or overcome.

In accordance with one aspect of the present invention a method of constructing a synthetic sports surface comprises preparing a substantially smooth sub-base, laying on said sub-base a base layer (optionally of resilient porous material), forming on said base layer a synthetic surface covering comprising a plurality of strips of synthetic surface material, and securing neighbouring edges of successive strips to the base layer by means of electrically activatable adhesive tape positioned between the cover and base layers.

The electrically activatable adhesive tape may be of a kind comprising a resistive member extending the length of the tape. When a current is caused to flow through said member the tape becomes heated thereby to result in activation of the adhesive which provides a bond when subsequently cooled.

Preferably the adhesive is of a kind which is re-activatable by electrical heating so that the adhesive bond between the surface cover and the base layer may be released over selected areas of the sports surface to assist in effecting any repairs which become necessary subsequent to installation.

In addition to securing the edges of cover layer strips to the base layer the electrically activatable adhesive tape may be used to secure together the cover and base layers at positions remote from the edges of the strips of the cover layer.

Preferably a grid arrangement of adhesive tape is provided between the base and cover layers, with at least some or all of the tapes which extend in one direction coinciding with a respective edge of a cover layer strip. Preferably a single adhesive strip serves to secure to the base layer each of the edges of a neighbouring pair of cover layer strips.

The invention provides in accordance with another of its aspects a synthetic sports surface constructed as described above and comprising a plurality of strips of synthetic surface material laid side-by-side, the neighbouring edges of successive strips being secured to a base layer by means of electrically activatable adhesive tape.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing which is a plan view of a sports surface, successive layers being shown part cut away.

A synthetic grass tennis court surface 10 is constructed over an existing shale surfaced court 11 and comprises a shock absorbing base layer 1 2 applied over the shale and in turn covered by a layer of synthetic grass material 1 3.

To construct the synthetic grass surface 10 the existing shale court 11 is levelled and compacted. It is then given a dressing of brick dust or like material which is relatively fine compared with the shale and thus results in a very smooth and firm surface.

Strips 14 of resilient porous material, such as crumb rubber urethane, of a width 1.22 metres and thickness in the order of 4 to 1 2mm are laid side-by-side to cover the required area. A gap of in the range approximately 3 to 1 8mm is left between the neighbouring edges of successive strips to allow for transverse expansion of the strips which are then secured to the shale. Securing is effected by means of 1 Ocm long rough galvanised nails 1 5 driven through the strips 1 4 and arranged at 45cm intervals in two staggered rows 1 6 extending, 40cm apart, along the centre of each strip.

Where transverse seams 1 7 are required in the strips 14, the ends of the strips are cut at right angles to the length of the strips, and then secured to the shale by means of additional nails arranged at 30cm intervals in two rows 18 spaced 7.5cm either side of the transverse joint.

The resilient base layer 1 2 so formed is allowed to weather for several days and any residual puckers subsequently revealed are removed by refitting of the strips 14 prior to construction of the synthetic grass covering surface 13.

Construction of the covering 1 3 first requires the laying of a series of electrically activatable adhesive tapes 1 9 arranged parallel with one another and the crumb rubber urethane strips 14, and spaced at 2 metre intervals. The tapes 1 9 are lightly bonded to the resilient strips 1 4 by means of a latex solution in order to retain them in position during subsequent application of the surface covering 1 3. The tapes 1 9 are of a double sided type having adhesive at both surfaces such that when heated and subsequently cooled they become fully adhered to both the resilient strips 1 4 and the surface covering layer.

The covering is then formed by unrolling 4 metre wide bands 20 of synthetic grass material in a direction transverse to that of the strips 14 and the tapes 1 9.

In contrast to the resilient strips 14, adjacent edges of the bands 20 are arranged in butt joined fashion. The neighbouring edges are lifted slightly subsequent to positioning of the bands, and 5cm wide rubberised strengthening tapes 21 are secured with adhesive to the resilient base layer. The strengthening tapes are then overlaid centrally with a single sided electrically activatable adhesive tape 22 arranged with the electrically activatable adhesive side uppermost and the other side secured by means of latex adhesive to the strengthening tape 21.

After covering the resilient base layer 1 2 with bands 1 9 of synthetic grass material and a network of electrically activatable adhesive tapes 19,22, the tapes are energised to effect firm bonding to the surface layer bands 1 9 to the strips 14 of the base layer.

Subsequently the surface is rolled to further ensure good bonding and urge the relatively thicker seamed regions of the surface into the shale thereby to provide an even playing surface.

If subsequently it is necessary to repair a part of the sports surface the electrically activatable adhesive tapes can be selectively reenergised thereby readily permitting removal of selected parts of the surface.

Claims (16)

1. Method for constructing a synthetic sports surface comprising preparing a substantially smooth sub-base, laying on said sub-base a base layer, forming on said base layer a synthetic surface covering comprising a plurality of strips of synthetic surface material, and securing neighbouring edges of successive strips to the base layer by means of electrically activatable adhesive tape positioned between the cover and base layers.

2. Method according to claim 1 wherein there is formed on the sub-base a base layer of resilient porous material.

3. Method according to claim 1 or claim 2 wherein electrically activatable adhesive tape is used to secure together the cover and the base layers at positions remote from the edges of the strips of synthetic surface material.

4. Method according to any one of the preceding claims wherein a grid arrangement of electrically activatable adhesive tape is formed between the base and cover layers.

5. Method according to claim 4 wherein at least some of the tapes extend in a direction parallel with a respective edge of a strip of synthetic surface material.

6. Method according to any one of the preceding claims wherein a single adhesive strip serves to secure to the base layer neighbouring surface material.

7. Method according to any one of the preceding claims wherein electrically activatable adhesive tape is laid on the base layer prior to laying of synthetic surface material.

8. Method according to claim 7 wherein prior to application of the synthetic surface material the electrically activatable adhesive tape is lightly bonded to the base layer.

9. Method for constructing a synthetic sports surface in accordance with claim 1 and substantially as hereinbefore described with reference to the accompanying drawings.

10. A synthetic sports surface constructed by a method in accordance with any one of the preceding claims.

11. A synthetic sports surface comprising a plurality of strips of synthetic surface material laid side-by-side, the neighbouring edges of successive strips being secured to a base layer by means of electrically activatable adhesive tape.

1 2. A synthetic sports surface according to claim 11 wherein the electrically activatable adhesive tape is of a kind comprising a resistive member.

1 3. A synthetic sports surface according to claim 11 or claim 1 2 wherein the adhesive tape is of a kind reactivatable by electrical heating so that the adhesive bond between the surface and cover layers may be selectively released.

14. A synthetic sports surface according to any one of claims 11 to 1 3 wherein the electrically activatable adhesive tape is of a double sided type having heat activatable adhesive at both surfaces.

1 5. A synthetic sports surface according to any one of claims 11 to 14 wherein the base layer comprises resilient porous material.

16. A synthetic sports surface according to any one of claims 11 to 1 5 wherein a single adhesive strip serves to secure to the base layer neighbouring edges of a neighbouring pair of trips of synthetic surface material.

1 7. A synthetic sports surface constructed and arranged substantially as hereinbefore described with reference to the accompanying drawing.