The invention relates to a plastics sheet, particularly but not exclusively for use in a gravity feed dispenser.

In gravity feed dispensers, articles to be dispensed are supported on a surface and encouraged to feed towards a dispensing point under the influence of gravity. Clearly the efficiency of such dispensers depends largely upon the coefficient of friction between the articles to be dispensed and the surface on which they are supported. The lower the coefficient of friction, the more reliable the dispenser. Known surfaces of this type have been specifically designed with regular grooves or ridges arranged in a triangular or corrugated configuration in an attempt to reduce the coefficient of friction by reducing the area of contact between the support surface and the articles. Production of sheets with such surfaces involve the use of special rollers which increase the costs involved and are not always particularly reliable.

An object of the invention is to provide a plastics sheet suitable for use in a gravity feed dispenser, wherein the coefficient of friction between the sheet surface and articles to be supported thereon is

reduced. A further object is to produce such a sheet at reasonable cost.

The invention provides a plastics sheet having a surface upon which articles are intended to be supported and across which the articles are intended to slide, the surface comprising a continuous pattern of irregularly shaped troughs and mounds spaced at irregular intervals over the surface such that the coefficient of friction between the sheet and the articles is reduced. The irregular pattern of troughs and mounds has been found to greatly reduce the coefficient of friction between the sheet surface and virtually any article which is placed thereon. The sheet does not rely on minimal contact surface to reduce the coefficient of friction; indeed the contact surface area is relatively large. It can be maufactured by a standard embossing roller widely used in the industry and therefore does not require special rollers to be made, thus keeping the cost of the sheet to a reasonable level.

Preferably, the pattern of troughs and mounds extends continuously over the entire surface of the sheet, which is preferably planar but could be shaped to provide, for example, _^ separate channels for different products to be dispensed.

The average depth of the troughs is advantageously between lOOμ and 150μm. The average length of the troughs is advantageously between 1mm and 5mm. These

dimensions have been shown to provide a substantial reduction in the coefficient of friction.

The plastics sheet is suitably formed of a synthetic thermoplastic material such as high impact polystyrene. In order to reduce the coefficient of friction of the plastics material itself, it may suitably contain a lubricant such as Dow Corning 200 Silicone Fluid (TM), conveniently in an amount of 0.05 to 5% by weight. The larger the contact surface area, the greater the amount of lubrication of the surface.

The invention also provides a shelf for a gravity feed dispenser, comprising a plastics sheet as described above. The shelf, or a sheet therefor, can be thermo-formed (vacuum-formed) incorporating moulded features such as product divisions or steps if desired without any apparent increase in the coefficient of friction.

The invention will now be described by way of example only with reference to the accompanying drawings wherein;

Figure 1 is an enlarged view of part of a plastics sheet according to the invention; and

Figure 2 is a further enlarged side view of the sheet of Figure 1.

The figures show a sheet 1 formed from high impact polystyrene with a lubricating additive of Dow Corning 200 Silicone Fluid (TM) on whose upper surface is

arranged a continuous pattern of irregularly shaped troughs 3 and mounds 2. The ^* pattern extends over the entire upper surface of the sheet 1. The troughs 3 are all of substantially the same depth 4 relative to the plane of the uppermost points of the mounds 2. This depth 4 is substantially 125μιtι.

The irregular pattern can be moulded into the upper surface of the sheet 1 during formation or can be introduced to the surface after the sheet ^" ! has been formed, for example by means of an embossing roll. The sheet 1 can then be used to form a shelf for a gravity feed device. If required, the shelf can consist solely of a sheet 2 as described above or may comprise a supporting member having selected portions consisting of separate sheets 1. The selected portions could be separated by dividers if desired.

A gravity feed dispenser having such a shelf is highly efficient in that the coefficient of friction between the articles to be dispensed and the shelf upon which they are supported is very low. The articles are thus fed to the dispensing point with very little risk of becoming jammed or stuck due to friction. This means also that the range of products which can be dispensed by that dispenser is increased.