FR2793445A1 - Pneumatic tire for all types of vehicle, has wear indicator formed in layer(s) beneath tread and providing contrasting color when tire about to reach dangerous condition - Google Patents

Abstract

A pneumatic tire has a wear indicator formed in layer(s) beneath the tread and providing a contrasting color when the tire is about to reach a dangerous condition. The indicator may be diagonal (dis)continuous colored band(s) of symbols, e.g. circles, triangles, and located between two layers of the carcass or belts of the tire. The bands are included during manufacture of the tire. The degree of color may indicate the wear of the tire.

Description

The present invention relates to a tire intended to equip all types of vehicles, that is to say automobile, motorcycle, airplane, truck, industrial machine, etc.

In known manner, the tires fitted to these vehicles consist of a tire comprising: an internal coating, a multilayer carcass, at least one belt layer, and a tread.

It has often been noticed that the control of the tires is not done regularly enough by the user of the vehicle.

At best, it is done by the mechanic during an engine oil change or any other intervention on the vehicle.

This is not enough when you know that the changes of a vehicle can be carried out every 7,500 km.

It is clear that the time to complete such a route is relatively long and that during this period may occur either a lack of parallelism, or an accidental blow in the tire on its tread in contact with the ground or on the interior or exterior flank. This is very dangerous and can, in some cases, cause the tire to burst, which will cause the vehicle to lose control. This then becomes an uncontrollable projectile which, according to statistics, is the cause of many road accidents.

In this situation, the object of the present invention is to allow easy control of the condition of the tires of a user's vehicle, not only without necessarily having recourse to a professional but also by a simple visual observation, which can even be carried out at distance, each time you take your vehicle.

To this end, the invention relates to a tire for all types of vehicle of the type constituted by a tire comprising at least one multilayer carcass, at least one belt layer, a tread, characterized in that it comprises an indicator d 'integrated wear, consisting of a coloration of all or part of the thickness formed by the constituent elements of the tire located under the tread and producing an effect contrasting with the color of the latter when its wear reaches a safety threshold.

The present invention also relates to the characteristics which will emerge during the description which follows and which should be considered in isolation or according to all their possible technical combination.

This description given by way of nonlimiting example will make it easier to understand how the invention can be produced with reference to the attached drawings in which - FIG. 1 is a partial view of a tire in perspective, in a cross section, - FIG. 2 is a schematic view in cross section of the thickness of a tire according to an alternative embodiment.

The tire 1 shown in the figures comprises in a known manner at least one carcass 3 formed from a plurality of layers 3a, a belt 4 also formed from at least one, or even a plurality of layers 4a, and a tread 5. An internal coating 2 is possibly provided under said carcass 3.

According to the invention, this tire comprises an integrated wear indicator 6 generally constituted by a coloration of all or part of the thickness formed by the constituent elements 3, 4 of the tire, located under the tread 5, in particular between this last and the inner lining 2.

The purpose of this coloration is to produce a contrasting effect with the color of the tread 5 when the wear thereof reaches a safety threshold.

Thus, when the wear of the authorized thickness of the tire has reached its maximum, it will reveal a different white or other color.

It is in this way that the visual control can be carried out easily by anyone.

This part of the tire which must be colored, will receive all the chemical or organic additives necessary to make it the desired color: for example to obtain a white color, titanium dioxide and a reinforced mineral filler such as silica will be added to the rubber. or chalk.

 Also, by this visual means, everyone will be able to see on a vehicle whether the tire is worn or dangerous and that whether the vehicle is stopped or running.

The color change which indicates the visual wear of the tire can be achieved in a multitude of ways, and using a multitude of colors. Several different colors can be used for the same tire.

Then, from this concept, a multitude of exemplary embodiments can be imagined, thus according to a first example, the wear indicator 6 is constituted by a plurality of continuous or discontinuous bands of color which is interposed between two layers 3a constituting the carcass 3 and / or between two layers 4a of the belt 4. This is particularly well illustrated in FIG. 2. Said continuous or discontinuous bands are possibly of different colors, interposed between successive layers 3a of the carcass 3 and / or successive layers 4a of the belt 4, so as to indicate different degrees of wear as a function of the color.

The mode of application of these strips may be carried out in a different manner, that is to say that they may be applied either by peripheral winding during the manufacture of the tire or else they may also be applied diagonally and cross manner during this same manufacturing.

According to an improvement of the invention, the aforementioned bands, whether peripheral or diagonal, also include markings such as circles, squares, triangles, etc. or any other marks, or even inscriptions, indicative of wear.

Preferably, according to the above examples, the bands forming the wear indicator 6 attached between the constituent layers of the bandage are made of an elastomer.

According to a variant of the basic inventive concept, all of the constituent elements 3, 4 of the tire, located under the tread 5, in particular between the latter and the coating 2, are colored in the mass according to a thickness A whose value O, with respect to that of the tread 5 is established according to a predetermined ratio, to constitute a wear indicator of a thick character.

In all the above-mentioned cases, the coloring of the bands constituting the wear indicator 6 or the coloring in the mass formed by the elements 3, 4, located under the tread 5, is carried out according to a width corresponding substantially to the width of said tread 5.

According to an improvement of the invention, the wear indicator 6 is extended to the internal 7a and external 7b sidewalls of the tire, by coloring all or part of the layers 3a forming the carcass 3 and which extend on the sidewalls 7a, 7b tire.

The layers 3a forming the belt 4 cannot be affected by this improvement because, as their name indicates, these are belt layers and which therefore do not extend over the sides.

According to the standards of each country, the wear indicator 6 will be placed at a depth corresponding to an authorized degree of wear.

The wear indicator 6 may be of any color but may also bear the colors of a national flag, for example blue, white, red for France, etc.

Claims (9)

<B> CLAIMS </B> 1. A tire for all types of vehicle of the type constituted by a tire comprising at least one multilayer carcass (3) (3a), at least one belt layer (4a) (4), and a tread (4), characterized in that it comprises an integrated wear indicator (6) constituted by a coloring of all or part of the thickness formed by the constituent elements (3, 4) of the tire located under the tread (5) and producing an effect contrasting with the color of the latter, when its wear reaches a safety threshold. 2. A tire according to claim 1, characterized in that the wear indicator (6) is constituted by a plurality of continuous or discontinuous bands of color, interposed between two layers (3a, 4a) constituting the carcass (3) and / or the belt (4). 3. A tire according to claim 2, characterized in that the wear indicator consists of a plurality of continuous or discontinuous bands of different colors, inserted between successive layers (3a, 4) of the carcass (3) and / or the belt (4), so as to indicate degrees of wear depending on the color. 4. A tire according to claim 2 or 3, characterized in that the strips are applied by peripheral winding during its manufacture. 5. A tire according to claim 2 or 3, characterized in that the strip (s) are applied diagonally and crosswise during its manufacture. 6. A tire according to one of claims 2 to 5, characterized in that the strips also include markings such as circles, squares, triangles, etc. or any other mark indicative of wear. 7. A tire according to claim 1, characterized in that all of the constituent elements (3, 4), of the tire located under the tread (5) are colored in the mass according to a thickness A, the value of which with regard to that of the tread (5), is established according to a predetermined ratio, to constitute a wear indicator of thick character. 8. Tire according to one of claims 1 to 7, characterized in that the coloring of the strips or the coloring in the mass formed by the elements (3, 4), located under the tread (5), is carried out according to a width corresponding substantially thereto. 9. A tire according to claim 8, characterized in that the wear indicator (6) is extended to its internal (7a) and external (7b) sidewalls by coloring all or part of the layers (3a) forming the carcass ( 3) and which extend on said sidewalls (7a, 7b) of the tire.