This invention relates to roof tiles and in particular is concerned with a novel type of tile, and a process and apparatus for manufacturing the same. Roof tiles are conventionally made of concrete and are produced in many colours and profiles. Such tiles are generally provided with contoured interlocking regions along their side edges whereby when laid on a roof each tile is laterally interlocked with the neighbouring tiles in the same row. Considerable effort has been expended on developing new colours and new profiles, e.g. with pronounced "rolls", to improve the visual appearance of the tiles. Nevertheless it has been found difficult, using e.g. concrete as a material, to simulate the appearance of other materials such as wood or slate. This is desirable if wishing to provide a concrete substitute, e.g. for wooden shingles. ^' The use of contours is not significant in this regard, and indeed will be avoided if wishing to simulate wooden shingles for example. The use of colour. echniques has not been found adequate. Thus, viewed from one aspect the present invention provides a roof tile including contoured interlocking region along its side edges and having over at least the major part of the upper surface thereof a plurality of relatively shallow closely spaced, longitudinally extending grooves.

The effect of the grooves will be to provide relatively closely spaced ridges and valleys across the upper surface of the tile. It has been found that this produces a visible effect superior to that obtainable with colouring techniques. Thus, the ridges and valleys can, when viewed from a distance, simulate e.g. the grain in wood in a manner which could not be achieved merely by streaks of colour. The addition of streaks of colour enhances the effect, however. A preferred tile therefore has the grooves together with random streaks of colour on

its upper surface, such as streaks of dark brown to contrast with a light brown base. The streaks could be obtained for example using the method of U.K. Patent 1,577,321 or by any other suitable method. A further advantage of having ridges and valleys extending longitudinally down the tile is that they will promote the flow of rainwater down the tiles and inhibit flow across the tiles.

The appearance of the tile may be further enhanced by having upwardly extending grooves in the lower end face of the tile. The upper end face need not be so treated as it will hot be visible in use. The appearance may also be enhanced by varying the lateral spacing between the grooves, preferably in a random manner. Thus between 3 and 12 grooves may for example be provided per inch. In combination with random colour streaking, this provides a particularly advantageous visual effect. The grooves are preferably no more than a quarter of an inch deep and this depth_ ay.vary _e.g...randomly. The tile will generally be made from concrete although other materials might be used. The tile can be manufactured by means of a modification- of the conventional process and thus viewed from another aspect the invention provides a process for manufacturing roof tiles wherein tile forming material is discharged onto a succession of pallets to form a base ribbon, the ribbon is compressed by means of a slipper and is subsequently cut into individual tiles , wherein the tiles are provided over at least the major part of the upper surface thereof with a plurality of relatively shallow, closely spaced, longitudinally extending grooves by means of ridges provided on the sl-ipper contacting the ribbon.

Apparatus in accordance with the invention may comprise means for transporting a succession of pallets in a longitudinal direction, means for discharging tile

forming material onto the pallets to form a ribbon, a slipper for. compressing the ribbon, and means for cutting the ribbon into individual tiles, wherein the slipper is provided over the major part of the surface thereof which contacts the ribbon with a plurality of relatively small, closely spaced, longitudinally extending ridges.

The means for .cutting the ribbon into individual tiles, such as a guillotine or the like, may be shaped so as to form grooves in at least one end face of the tile. These grooves may be aligned .with those in the upper surface and in any event may be of. a similar spacing and depth.

Streaks of colouring may be provided by introducing a secondary, colouring material into a hopper o the like for the tile forming material, e.g. concrete mortar, at randomly timed ^• intervals. Such processes are generally such that the streaks are formed mainly in the upper surface region of the tile. The action of the cutting means may cause the colouring to be pulled down the end face to add to the visual effect.

It will be appreciated that a significant advantage of the invention is that whilst an improved visual effect is obtained, and water control made possible, conventional techniques can be used with the exception that the slipper is modified in a simple yet effective manner.

The apparatus may include a roller, positioned before the slipper, to compress the tile forming material and this could also be provided with ^' ridges corresponding to those on the slipper and, of course, preferably aligned therewith.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings in which:-

Fig. 1 is a diagrammatic view of apparatus in accordance with the invention;

Fig. 2 is a view of part of the slipper in the direction of arrow II on Fig. 1; Fig. 3 is a view of part of the guillotine in the direction of arrow III on Fig. 1; and

Fig. 4 is a perspective view of a tile in accordance with the invention.

Referring now to Fig. 1, tile forming apparatus consists of a plurality of pallets 1 linked together and driven in the direction of arrow A. A hopper 2 is supplied with concrete mortar 3 through a feed chute 4. Rotating paddles 5 urges the mortar towards a roller 6 which compresses the mortar down onto pallets 1. The mortar then passes under a slipper 7 which finally compresses the mortar and shapes the upper surface. The mortar emerges as a continuous ribbon 8 and is cut into individual tiles 9 by the blade 10 of a guillotine lϊ. A secondary colouring material is supplied to hopper 2 by means of a feed pipe 12 positioned over roller 6.

The supply of colouring material is random and streaks of colour appear on the upper surface of the ribbon 8 and hence the tiles 9.

As shown in Fig. 2, the slipper 7 has a bottom surface 13 which contacts the upper surface of the ribbor. This has substantial contours 14 to mould the interlocking region of the tile. In accordance with the invention however, the surface 13 is also provided with a series of relatively closely spaced, longitudinally extending parallel small ridges 15. These ≤re positioned randomly across the slipper surface. The ridges are about a quarter of an inch high and vary in spacing between 3 and 12 per inch. They are exaggerated in size in Fig. ^* 2. The tiles themselves can be of any required size, e.g. having standard widths of say 6 % or 13 inches. These small rid es roduce corres ondin shallow rooves

tiles 9.

As shown in Fig. 3 the blade 10 of the guillotine 11 has its upstream face 16 provided with, ridges 17. Thus as the tiles 9 are cut from ribbon 8 by blade 10, grooves are formed in one end face, being that which will face down the roof in use. At the same time, streaks of colour are pulled down the end face.

Further handling of the tiles 9 is conventional. A finished tile is shown in Fig. 4. This has moulded contours on its bottom face 18, in accordance with the shape of pallets 1. The upper surface 19 is generally flat although it has an interlocking region 20 along one edge. Both the upper surface 19 and the lower end face 21 have grooves and streaks of colour thereon, produced in accordance with the invention. It has been found that dark brown streaks on a lighter brown background, in combination with the parallel grooves, provides a good simulation of wood grain.