GB2347384A

GB2347384A - Sports playing surfaces

Info

Publication number: GB2347384A
Application number: GB0005134A
Authority: GB
Inventors: John Anthony Hessey
Original assignee: VERDE SPORTS Ltd
Current assignee: VERDE SPORTS Ltd
Priority date: 1999-03-04
Filing date: 2000-03-06
Publication date: 2000-09-06
Anticipated expiration: 2020-03-06
Also published as: GB0005134D0; GB2347384B; GB9904966D0

Abstract

A sports playing surface such as for flat or crown green bowls comprises a stable scrim (20) sandwiched between respective layers (22, 24) of polypropylene fibres and bonded thereto by needle punching. The scrim is of open mesh structure and of a weight less than 160gm<SP>-2</SP>. The scrim may be woven of flat polypropylene, or it may be woven or formed by non-woven techniques from a mixture of such tape and other fibres. A suitable minimum mesh size is 1mm x 1mm. Adjacent lengths may be joined together by overlapping their edges, stitching the lengths together along the edges applying a flexible polyurethane adhesive to the edges and moving the lengths from an overlapping relationship to an abutting relationship.

Description

IMPROVEMENTS IN OR RELATING TO SPORTS PLAYING SURFACES The present invention relates to a sports playing surface and a method of manufacturing such a surface. In particular, though not exclusively, the invention relates to a playing surface for flat or crown green bowls.

A playing surface for playing flat or crown green bowls is required to be laid upon a level and smooth base. In the case of outdoor use the base should be surfaced with porous macadam or concrete provided with adequate drainage grids. The playing surface itself is usually manufactured in panels up to 6 metres in width. Requirements for the playing surface are as follows: -it needs to be porous to allow the passage of rainwater to the drainage grids in the base construction; -it needs to be resilient to prevent compaction from foot traffic or weathering; -it needs to be hard wearing to give a life of approximately 10 years or more under normal usage; -it needs to be surfaced with weather and ultra-violet light resistant fibres to counter degradation; -it needs to be capable of being joined to give an overall size up to 40 metres by 40 metres approximately, with the joints secured under tension and smooth to prevent deflection of bowls; and -it needs to be capable of being tensioned and fixed so that it is held flat upon the base but will allow for expansion and contraction due to changes in temperature and humidity.

An underlay between the playing surface and the base can be fitted if required. The underlay has to meet similar requirements to that of the playing surface i. e. be porous to allow the passage of rainwater, be resilient to prevent compaction from foot traffic or weathering and be joined to give a smooth surface.

To meet the above requirements, the applicant has hitherto been supplying a sports playing surface material comprising a tough, dimensionally stable scrim of flat, woven polypropylene tape and a layer on each side of the scrim of polypropylene fibres, the three layers being bonded together by needle punching.

This has proved satisfactory, but is expensive to produce compared to competing products which are woven or comprise tufted artificial grass.

An object of the present invention is to provide a comparable product which is both less expensive and easier to manufacture, and has improved properties in use.

According to the invention a sports playing surface comprises a stable scrim layer sandwiched between respective layers of polypropylene fibres, the three layers being bonded together by needle punching characterised in that the scrim has an open mesh structure and a weight of less than 160gm2. In this respect, a scrim weight of between 50 and 100/m2 is probably most suitable.

Preferably the scrim has a mesh aperture size of at least 1mm x 1mm.

Preferably the needle punching is effected predominantly from one surface, which is to be the undersurface when the material is installed for use. This results in a smoother, non-directional top surface when the material is laid.

The scrim may be woven entirely of flat polypropylene tape, or it may have a warp or weft of polypropylene tape, with the other strand being of another type, for example, a yarn of natural jute fibres. In either case, less than 40 x 30 ends per 10cm will conveniently produce a suitable mesh aperture size.

Alternatively, the mesh scrim may be produced as a non-woven fabric, e. g. by spinbonding, meltblowing, or hydroentanglement techniques, using a fibrous yarn or fibres for at least one part of the material.

Use of the open mesh scrim, according to the invention, minimises break-up of the scrim and minimises the frequency with which the scrim is pushed to the surface during the needle punching operation. Thus, it provides a better surface finish than hitherto. Also, while such a scrim provides adequate dimensional stability it is much less expensive than that used hitherto-often less than 10% of the previous cost.

The invention further provides a sports playing surface comprising two or more layers of material according to the present invention in which adjacent lengths are joined together by laying said two adjacent lengths over one another so that two longitudinal edges coincide, stitching the lengths together along the said edges, applying a flexible polyurethane adhesive to the edges of the lengths and moving the lengths into an abutting relationship so that the edges of adjacent lengths abut one another.

The thread used for stitching the lengths together preferably comprise spun stainless steel wire.

The present invention will now be more particularly described with reference to the accompanying drawings in which: Figure 1 is an exploded, partial perspective view of a portion of previously known playing surface material; Figure 2 is an enlarged detail of the encircled area in Figure 1 showing the structure of the scrim; Figure 3 is a fragmentary, exploded side view of the material shown in Figure 1; Figure 4 is a view corresponding to Figure 1 of a portion of playing surface material according to the present invention; Figure 5 is an enlarged detail of the encircled area in Figure 4, again to show the structure of the scrim; Figure 6 is a fragmentary, exploded side view of the material shown in Figure 4; Figure 7 is a diagrammatic end elevation of two lengths of material shown in Figure 4 joined together in an overlapping relationship; and Figure 8 shows the lengths of material shown in Figure 7 in an abutting relationship to form part of a complete playing surface.

Referring to Figures 1 to 3 of the drawings, the previous playing surface material supplied by the applicants is shown to comprise a scrim (10) of woven polypropylene ribbon and two layers (12, 14) of needle punched polypropylene fibres located on opposite sides of the scrim (10). The illustrated example of the scrim material used might have a fabric weight of 330 gm/m2 and a weave construction of about 60 x 60 ends/1Ocm. It will be noted that the woven structure is closely packed, with only small apertures between the warp and weft ribbons. It is also relatively thick, with both warp and weft strands undulating, as is apparent in Figure 3. The polypropylene used is green and it is UV and colour stabilised.

Referring now to Figures 4 to 6 of the drawings, a preferred practical embodiment of the improved playing surface material according to the invention comprises a scrim (20) sandwiched between two layers (22,24) of polypropylene fibres. They are bonded together by needle punching. In this case, the scrim (10) is of a much more open mesh. It comprises a polypropylene warp strand woven with natural jute as weft strand. The size of the apertures is approximately 2mm x 2mm. Actually, the woven construction is roughly 30 x 25 ends per 10cm. The fabric weight is between 55 and 65 gm/m2. As shown in Figure 6, the overall construction is much flatter and thinner, than the previous scrim (10), as well as being lighter and having a much more open structure altogether.

Figures 7 and 8 illustrate the preferred method of joining together two lengths (16,18) of the playing surface.

In Figure 7, the lengths (16,18) are laid one over the other so that the longitudinal edges of the lengths (16, 18) coincide with one another. The lengths (16,18) of material are then stitched together by stainless steel thread e. g. using blanket stitches (26).

A flexible polyurethane adhesive is then applied to the exposed longitudinal edges of the lengths (16, 18) to also cover that part of the stitching in the region of the said exposed edges.

As illustrated in Figure 8, the length (16) is then laid flat so that the lengths (16,18) abut one another along their longitudinal edges and the adhesive assists in bonding the lengths together.

Further lengths of material according to the present invention are added successively to either one or both of the lengths (16, 18) in order to form the complete sports playing surface. The complete sports playing surface fully covers the pre-prepared base, either directly or by the use of an intermediate underlay, and the complete sports playing surface is then tensioned and fixed on the base to provide the appropriate surface, for example, for the playing of flat or crown green bowls.

Claims

CLAIMS 1. A sports playing surface material comprising a stable scrim layer sandwiched between respective layers of polypropylene fibres, the three layers being bonded together by needle punching characterised in that the scrim has an open mesh structure and a weight of less than 160gm-2.
2. A material according to claim 1 wherein the scrim includes flat polypropylene tape.
3. A material according to claim 1 or 2 wherein the scrim is of woven construction.
4. A material according to claim 3 wherein the scrim has less than 40 x 30 ends per 10cm.
5. A material according to claim 1 or 2 wherein the scrim is formed as a non-woven mesh.
6. A material according to any preceding claim wherein the scrim has a mesh aperture size of at least 1mm x 1mm.
7. A material according to any preceding claim wherein the needle punching is effected predominantly from one surface, which is to be the undersurface when the material is installed for use.
8. A sports playing surface comprising two or more lengths of material as claimed in any preceding claim in which adjacent lengths are joined together by laying the adjacent lengths over one another so that two longitudinal edges coincide, stitching the lengths together along the said edges, applying a flexible polyurethane adhesive to the longitudinal edges, and moving the lengths from an overlapping relationship to an abutting relationship.
9. A sports playing surface as claimed in claim 8 in which the stitching thread comprises spun stainless steel wire.
10. A sports playing surface material substantially as herein described with reference to and as illustrated in Figures 4 to 8 of the accompanying drawings.
11. A method of making a sports playing surface as herein described.