This invention relates to an edge-restraining device, which can be used with advantage in place of the conventional kerbstones. In particular the device is for edging roads or pathways made up of small element paving. However, the invention is not limited to this application since it will find use in ornamental gardens, sports complexes, public open spaces, and other situations where an edging of neat appearance, which is also cheap to manufacture and lay, is required.

The conventional kerbstone has been known for hundreds of years and under modern practice is usually maintained in position, before the road surface is laid, by "haunching", that is to say laying concrete or mortar to hold it in position which is then allowed to dry. It would be desirable to avoid this costly extra step. A proposal has been made, see U.S. Patent No. 4,863,307, to use a plastics edging strip which is held in position by a series of vertical headed spikes which extend through the strip and into a compacted aggregate base. This system is claimed to give some restraint at the edge of an area of paving. A similar concept is employed in certain paving systems on offer in U.S.A., known as "BRIC-EDG", "SNAP-EDGE" and "DIAMOND-LOK". Defects of systems which rely on spikes to hold edging in place are that the support against lateral forces is dependent on the characteristics of the material into which the spikes are driven, and extra costs in laying are incurred due to the labour employed to drive in the spikes.

The present invention aims to provide an improved edge-restraining device.

According to the invention, there is provided an edge-restraining device which includes an elongate upstanding edge-restraining member securely connected to a mesh or mat of geogrid material as herein defined.

In use, the edge-restraining member is located where required, and serves in place of conventional kerb-stones, and the mesh or mat is extended as necessary, e.g. in a generally horizontal direction. The road or path surfacing material usually (paving blocks, or occasionally tarmacadam, or any other

desired surfacing material) is then laid so that mesh or mat is trapped between a base course and the laying course (usually sand). Thus, the mesh or mat, and hence the elongate edge-restraining member, is held firmly in position against generally horizontal movement.

The edge-restraining member is preferably of synthetic plastics material, and may be extruded for ease of manufacture.

The connection between the member and the mesh or mat may be made in any suitable way, e.g. by adhesive, by stapling, or by a plastics heat or RF or hot-air welding procedure.

It is an important feature of the present invention that displacement of the edge-restraining member is resisted by tensile forces in the geogrid mesh or mat. The mesh or mat is prevented from making any movement in a generally horizontal direction due to its interengagement with the random material of the base course. The base course is usually broken rock, or chippings, or small size rubble.

This is a contrast with known constructions in which an edge member is maintained in position by spikes or pins driven through the edge member and into , the ground. Such constructions are usually unable to effectively resist lateral forces which are likely to be encountered in normal use.

In the use of the present invention, the mesh or mat becomes an integral part of the pavement or roadway construction, but is not visible, and the use of this invention obviates the need for the "wet trade" of laying newly mixed concrete to hold or "haunch" kerb stones in position. It also obviates the need for spikes to be driven in, at frequent intervals. Hence edge restraint is substantially simpler, quicker and less expensive than with prior art methods and products.

The edge-restraining device may also be used in domestic gardens where durable, easily laid edges of neat appearance are desired.

The invention will be better understood from the following non-limiting description of examples thereof given with reference to the accompanying drawings in which:-

Figure 1 is a perspective view of one example of the invention;

Figure 2 is a cross-sectional view of the arrangement shown in Figure 1, illustrating its edge-restraining relationship with the laid blocks which will provide a paved surface; and

Figure 3 is a perspective view illustrating an arrangement according to the invention and which permits a non-90° configuration of two parts of an edge-restraining member.

Referring firstly to Figures 1 and 2, an edging device according to the invention is illustrated which includes an elongate upstanding edge defining member 10 of synthetic plastics material. This member 10 is L-shaped as seen in cross section, having an upstanding limb 12 and a horizontally extending limb 14. The member 10 may be a plastics extrusion. To the underside of the horizontally extending limb 14 is secured, in a substantially permanent manner, a mesh or mat 16 of geogrid material. The term "geogrid" in this context is used to mean any open mesh or perforated mat of textile, synthetic plastics or other flexible material which can be laid between a laying course 18, which is usually sand, and which immediately underlies the surface paving blocks 20 when they are laid, and a base layer or base course 22 which is usually rubble, aggregate, or broken and chipped rocks or stones. When so laid a geogrid layer as herein described interlocks to some extent with the material of the base layer. Consequently the geogrid is prevented from making any significant lateral movement. Such movement of the edge-restraining member (which is firmly secured to the geogrid) is likewise prevented. The geogrid mesh or mat 16 is connected to the limb 14 in any suitable manner giving adequate strength and permanency of connection, for example by adhesive, by a plastics welding procedure (in the case of a geotextile material incorporating suitable plastics), or by stapling or other fastening methods. The material known by the Registered Trade Mark "NETLON" and available from the Company of that name may be used for the geogrid 16. In some circumstances, it may be possible to dispense with the sand layer.

In use, sand 18 and path or road material 20, e.g. paving blocks as illustrated or tarmacadam or concrete, are laid over the limb 14 see Figure 2, and the geotextile material 16, and one lateral edge thereof is bounded by the

upstanding limb 12. The road or path material when laid securely maintains and anchors the geogrid 16 and the limb 14 in position and so ensures the proper maintenance and location of the edge restraining limb 12.

It is to be noted that a condition of maximum stress on the edge- restraining member 10 arises when a wheel of a heavy vehicle runs on that part of the road surface closely adjacent to the edge restraining member. With prior art constructions such a stress would often result in deformation or dislodgement of the kerb or equivalent member. However, with the arrangement according to the present invention, the heavy weight of the vehicle, transmitted through the wheel and then the paving block and the laying course, enhances the interlock and interengagement between the geogrid mesh or mat and the base layer and so any tendency of the mesh or mat and hence the edge-restraining member to be dislodged is automatically resisted.

The edge restraining member 10 may be made in sections of any desired length, for example it may be made in units of one metre length, or two metre length, or any other convenient size. Although in Figure 1 the limbs 12 and 14 have been shown of approximately equal size, the invention is not considered to be limited to any particular size or shape relationship between these limbs. As seen in Figures 1 and 2, a short flange may be provided at the upper edge of the limb 12.

Referring now to Figure 3, this shows a version of the invention in which the elongate upstanding edge-restraining member is required to define an edge which has straight portions which join each other at various angles.

The edge-restraining member 110 shown in Figure 3 has parts of its horizontal flange 140 cut away prior to the attachment thereto of the geogrid 160. The resulting recesses are illustrated at 162. As a result, the upstanding limb 120 of this member becomes readily deformable by hand and during the laying of an edge-restraining member the member can be bent as desired. In this way the limbs 120 can be made to follow a non-linear or cranked configuration in a horizontal plane. The geogrid 160 is then securely attached to the non-removed parts of the limb 140 in the manner illustrated. As seen at

the middle part of Figure 3, one geogrid portion 160A can overlay another 160B. The laying course, e.g. sand, is then laid over the geogrid and a suitable road or path surface laid thereon.

It will be appreciated that edge-restraining members 10 or 110 of different shape could be employed if particular technical or aesthetic effects are desired. While the road material has been mentioned as paving stones or blocks, it could equally well be other suitable materials, e.g. concrete or tarmacadam. Other variations and improvements, which would be considered within the scope of the invention, will occur to the man skilled in the art.