GB2376002A

GB2376002A - Tyre wear indicator

Info

Publication number: GB2376002A
Application number: GB0112902A
Authority: GB
Inventors: James Pibworth; Catherine Anne Jessup; Sarah Jane Markham
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-05-29
Filing date: 2001-05-29
Publication date: 2002-12-04
Also published as: GB0112902D0

Abstract

A pneumatic tyre 2 has an indicator means 14 embedded in a tread portion 10 below the surface. The indicator is made of rubber and brightly coloured in contrast to the tread to enable a visual warning once exposed by tread wear. The indicator extends around the circumference of the tyre and may be in the form of a band, a number of strips, or a number of plugs, all positioned across the tread portion. The depth of the indicator may be located at the minimum legal tread depth or before the minimum to provide a safety margin.

Description

AN IMPROVEMENT TO TYRES The present invention relates to an improvement to tyres, in particular an improvement to the safety thereof.

The tread on a tyre is important in wet conditions. The tread allows for the dispersal of water ensuring that the tyre is in constant contact with the road.

The tread of pneumatic tyres gets worn down with use. When the tread has reached its minimum legal limit, the tyres become unsafe on the road. The tread can no longer maintain the traction required in wet conditions and aquaplaning may occur. A number of road accidents every year are the result of worn tyres.

At present, one way of telling if a tyre has reached its legal limit in terms of tread wear is by way of wear bars. The wear bars are raised strips of rubber that are positioned within the tread at several points around the tyre. The height of the strips is that of the legal minimum for tread wear. When the tread has worn down to the legal limit, the top of the wear bar will be flush with the surface of the tyre. This indicates that the tyre should be replaced. A disadvantage of this method of telling if the tyre tread has reach its legal limit is that it can be difficult to see the wear bars without inspecting the tyre carefully. The wear bars cannot be seen when the vehicle is in motion.

It is an object of the present invention to provide an improvement to a tyre that mitigates the afore-mentioned problem.

According to the present invention there is provided a tyre having a tread portion including an indicator means, said indicator means being of a contrasting colour to the tread portion and embedded within the tread portion below the surface thereof, such that the indicator means is visible only when the tread portion has been worn away sufficiently to expose the indicator means.

The invention provides an easy way of assessing tyre wear and seeing when a tyre is in need of replacement. The contrasting colour of the indicator means is easily seen, with the result that individuals or companies would not be able to run a vehicle with worn tyres without law enforcement agents and other road users being able to see that the vehicle has worn

tyres, not only when the vehicle is stationary but also when it is moving. This would encourage individuals and companies to replace tyres as soon as they become excessively worn. This may help to reduce the number of worn tyres on the roads, and assist in making the roads safer.

Preferably, the indicator means is provided round the circumference of the tread portion.

Preferably, the indicator means includes a band extending across the tread portion, or a number of strips or plugs positioned across the tread portion.

Preferably, the indicator means is visible when the tread portion has been worn away to the minimum legal tread depth.

Advantageously, the indicator means is made of rubber.

Preferably, the tyre is pneumatic.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a cross-section through a tyre showing a colour band inserted into the tread portion; Figure 2 is a cross-section through a tyre showing colour strips inserted into the tread portion; and Figure 3 is a cross-section through a tyre showing colour plugs inserted into the tread portion.

A pneumatic tyre 2 has an inner carcass covered by a natural or synthetic rubber material, forming a circumferential wall 4, two sidewall portions 6, and two bead portions 8 that in use engage the wheel rims. A thick rubber tread portion 10 is provided on the outer surface of the circumferential wall 4. The tread portion 10 includes a tread pattern for water dispersal. The tread pattern comprises a number of grooves 12 that extend into the tread portion.

The tyre includes an indicator means 14 that is embedded in the tread portion 10. The indicator means 14 comprises a rubber layer that is of a contrasting colour to that of the tread portion 10.

On a new tyre, the indicator means 14 is not visible. The indicator means is covered by the tread portion and is not exposed in the grooves 12. As the tyre tread wears, the indicator means is eventually exposed. The indicator means can then be easily seen, owing to its contrasting colour.

The indicator means 14 is positioned in the tread portion 10 so that it is exposed when the tread reaches the height of legal tread wear. When the height of the tread reaches its minimum legal limit, the indicator will be exposed, clearly indicating that the tyre needs to be replaced.

Alternative embodiments of the invention are shown in figures 2 and 3.

In figure 2, the indicator means 214 comprises a number of strips of rubber that are embedded into the tread portion 214 between the grooves 12.

In figure 3, the indicator means comprises a number of plugs of rubber that are embedded at various positions into the tread portion 314.

A number of possible modifications of invention are envisaged. For example, the indicator means may be embedded a little less deeply within the tread, so that it is exposed before the tyre reaches the legal limit, thereby providing a safety margin.

Claims

CLAIMS: 1. A tyre having a tread portion including an indicator means, said indicator means being of a contrasting colour to the tread portion and embedded within the tread portion below the surface thereof, such that the indicator means is visible only when the tread portion has been worn away sufficiently to expose the indicator means.
2. A tyre according to claim 1, wherein the indicator means is brightly coloured.
3. A tyre according to claim 1 or claim 2, wherein the indicator means is provided round the circumference of the tread portion.
4. A tyre according to claim 3, wherein the indicator means includes a band that extends across the tread portion.
5. A tyre according to claim 3, wherein the indicator means includes a number of strips positioned across the tread portion.
6. A tyre according to claim 3, wherein the indicator means includes a number of plugs positioned across the tread portion.
7. A tyre according to any one of the preceding claims, wherein the indicator means is visible when the tread portion has been worn away to the minimum legal tread depth.
8. A tyre according to any one of the preceding claims, wherein the indicator means is made of rubber.
9. A tyre according to any one of the preceding claims, wherein the tyre is pneumatic.