GB2472991A

GB2472991A - Tread wear indicator

Info

Publication number: GB2472991A
Application number: GB0914795A
Authority: GB
Inventors: Christopher Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-08-25
Filing date: 2009-08-25
Publication date: 2011-03-02
Also published as: GB0914795D0

Abstract

Tread wear indicators are disclosed, for use on a tyre of a vehicle. A number of studs are provided, each containing three different coloured pellets, welded together and to the stud. The pellets are arranged in the same colour configuration, such as red, yellow and then green. The stud exterior has corrugated sides, including slanted portions and horizontal portions. The slanted portions allow the stud to be easily inserted in the tyre, and the horizontal portions help the stud be retained in the tyre.

Description

Patent Application of Christopher Johnson for Tread Wear Indicator

Background of the Invention

[1] The present invention relates to a system for seeing when the tread of vehicle tyres has worn down, making the tyres less safe.

[2] Tread wear indicators are well known in the art for measuring how worn a tyre is. Tyres are built with tread marks to a certain depth, and this gives the tyre traction. With time, the tread gets worn down and the grooves shallower. Tread wear indicators present a solution for car owners to know when to change or retread their tyres.

[31 US Patent Application 20090095388 to Cuny et al. is directed to a tire tread for a vehicle tire with a plurality of tread elements extending radially outwardly from a tread base to a radially outer surface. Each tread element is defined by adjacent grooves. The tread has at least one tread element projecting from the tread base and having one or more tread wear indicators. Each tread wear indicator is located at the intersection of two grooves adjacent or integral to the at least one tread element.

[4] US Patent Application No. 20070163691 to Cuny et al. is directed to a tire that has at least one tread wear indicator.

Each wear indicator is a single mark that provides continuous information to the consumer, while changing its presentation based upon the amount of tread wear. The mold blade employed to form the ear indicator has a series of stacked portions, each portion having a different configuration, the configuration being constant for the length of each portion.

[5] US Patent Application No. 20070295432 to Posada et al. is directed to a pneumatic tire that has a tread with at least one groove having a groove depth Dg extending from an initial tread surface to the base of the groove. The tread has at least one tread wear indicator having at least two different colored portions. The tread wear indicator is a strip inclined at an angle relative to the tread surface and extending to a depth Dr at least equivalent to the groove depth Dg. In manufacturing the tire, the tread wear indicator is applied to a splice cut edge of the tread rubber such that, after splicing the tread rubber, the tread wear indicator strip is located within the tread splice.

[6] US Patent Application No. 20030205076 to Shimura, Kazuhiro November 6, 2003 is directed to an invention that provides a measuring method of a tread wear amount by using a pneumatic tire in which a mark portion is formed on a part of a tread surface, the mark portion changing its surface shape as wear progresses. Image data of the mark portion is detected, the detected data is inputted in processor means, and then the tread wear amount is determined by use of either ratio referential data of the mark portion inputted in advance and corresponding to the wear amounts of the tread surface, or a formula inputted in advance for computing the wear amount, thereby facilitating automatic measurement of the tread wear amount.

[7] US Patent Application No. 20060213594 to Kemp et al. is directed to a tire tread comprising a rolling surface and at least one wear indicator formed by at least one cavity which opens onto the rolling surface, wherein the geometrical shape of the trace of the cavity on the rolling surface changes as a function of the wear level of the tread and wherein the geometrical shape of said trace is an analogical expression of the tread's wear level.

[8] US Patent No. 5704999 is directed to a wear indicator strip for a pneumatic tire having a multiply carcass, such as a military aircraft tire, is located preferably between the two radially outermost carcass plies. The wear indicator strip is of a contrasting color and comprises and elastomeric compound of natural or polyisoprene rubber reinforced with silica.

[9] Us Patent No. 4,074,742 to Charnblin is directed to a multilayer adhesive strip is adhered to the tread of an automobile or other vehicle tire transversely of the tread and generally axially of the wheel. Each layer has a different color, and wear on one part of the strip faster than another will expose a different color or colors that will indicate the wear pattern.

Thin easily worn material may indicate the pattern in a mile or two of driving whereas thicker or tougher strips give results over a longer period of use. For example, differential wear in the center indicates over-inflation, differential wear at both ends indicates under-inflation, and differential wear at one end of the strip indicates wheel misalignment.

[10] US Patent No. 7,291,237 to O'Brien, et al. is directed to a tire in which a tire manufacturer has determined the tractive capacity at numerous levels of tread wear, the tire having at least one visual warning indicator located at a tread depth corresponding to a percentage loss of tractive capacity. It also teaches a method of making the tire and a method improving traffic safety through use of such a tire combined with educating the consumer as to proper use of the tire.

[11] US Patent No. 3,578,055 to French, et al is directed to a pneumatic tire having a recess formed in the tread rubber thereof by cutting or moulding a recess shoulder portion formed in the rubber bounding the recess, and a tread wear marker located in the recess having at least a part thereof located radially inwardly of the said shoulder portion and secured in position thereby, the marker comprising, at least in part, material which may be distinguished either visually or audibly upon rotation of the tire on a hard surface for indicating a degree of tread wear which has occurred in the rubber adjacent the marker.

Brief Summary of the Invention

[12] The present invention is directed towards tread wear indicators for a tyre. These include a plurality of studs, for insertion into the tyre, and three different coloured pellets for each stud. The three pellets are welded to one another in a colour configuration, and to the interior of the stud.

[13] The stud has an exterior of the following attributes.

It has a substantially flat base, and corrugated sides. The corrugated sides have slanted portions and horizontal portions.

The slanted portions allow the stud to be easily inserted in the tyre, while the horizontal portions help the stud be retained in the tyre.

[14] In a further embodiment, the tread wear indicators have a colour configuration that is red, yellow and green in the order from innermost pellet to outermost pellet. The tread wear indicators are preferably constructed from plastic. In one embodiment, four studs are applied in a parallel line, along the width of the tyre in each of four circumferential locations around the tyre, such as at 90 degree intervals. In one embodiment, the pellets have an even thickness, ie, all have identical dimensions to one another.

[15] The invention further teaches using a database detailing tyre characteristics of different types of tyres, and a machine for inserting and aligning the studs in a tyre according to tyre characteristics of the tyre, read from the database.

Also, the machine is capable of boring a pilot hole in the tyre in the positions where the tread wear indicators are to be inserted.

[16] In a preferred embodiment, the pellets are friction welded together and into the studs.

Brief Description of the Several Views of the Drawing [17] The invention can be better understood with reference to the following drawings, in which: [18] Fig la shows a cross-sectional view of a stud and pellets of the present invention.

[19] Fig lb shows an exploded view of the stud and pellets of the present invention.

[20] Fig 3 shows a configuration for the arrangement of the studs around a tyre, in an embodiment of the present invention.

Detailed Description of the Invention

[21] Tyres for vehicles are well known in the art. Traction is provided by the tread and grooves of the tyres. As tyres are used, or if they are misaligned, they tend to wear away, and the grooves become less deep. This does not provide adequate traction for the vehicle under wet or slippery conditions. With continued wear, the tyres become unsafe under also dry conditions. It is important for drivers -as well as other road users and the police, to be able to tell if tyres are road-worthy or not.

Otherwise, cars driven with such tyres become a hazard to everyone.

[22] Tread wear indicators are well known in the art. Many tyres are initially built with layers of colours or other marks which are only displayed as the tyres wear down. These include geometrical shapes, words, or even smiley faces that become frowning faces! However, most of the prior art as described above, teaches methods that are applied as the tyre is being built. The present invention is designed to be applied after the tyre is built, perhaps under the authority of a standards' agency.

[23] With regard to Fig la, stud 101 is shown, to be inserted into a tyre. Stud 101 has an exterior with sloping portions 102 and horizontal portions 103. Sloping portions 102 enable stud 101 to be easily inserted into the tyre, while horizontal portions 103 help stud 101 to be retained in the tyre after insertion. Stud has flat base 105 and flat top 107.

[24) As shown in Fig la, which shows a completed stud, and Fig lb, an exploded view of the stud and its three pellet contents, stud 101 houses three pellets 111, 112 and 113. Three pellets 111, 112 and 113 are inserted into stud 101, one above the other. Pellet 111 is innermost, at the base of stud 101, pellet 112 is located above pellet 111, and pellet 113 is the topmost pellet, inserted last. Pellets 111, 112 and 113 are basically thick discs, preferably made of plastic, or similar substrate that can be welded together.

[25J In a first embodiment, it is desired that pellets have a uniform thickness, and as the tyre is worn down, the pellets wear down uniformly with tyre wear. Thus the pellets give graded information of how worn the tyres are. In a second embodiment, it is calculated for each type of tyre how much tyre wear depth is associated with the tyre being less safe (for example, suitable only for driving in dry conditions), and how much tyre wear depth is associated with the tyre being dangerous. The thickness of the pellets is then created according to this, so that second pellet 112 becomes visible when a tread wear is reached that is less safe, and pellet 111 becomes visible when a tread wear is reached that is dangerous.

[261 Preferably three different coloured pellets are used, for example green, yellow and red. The first colour to be visible is the one that has been inserted topmost in the stud. As this is worn down, the second colour becomes visible and then as this is worn down, the third colour becomes visible. In one example, topmost pellet 113 is green, as this is often associated with safety, second pellet 112 is yellow, and base pellet, 111 is red, as this colour is often associated with danger. However, these colours are not mandatory for this invention to work, other colours could be used.

[27] It is a further embodiment of the invention to establish a set of colours to be uniform throughout a region, such as throughout a country, state, or jurisdiction. In a further embodiment, it would be preferable to provide bright or fluorescent colours that can be easily seen at a distance and will not easily become dull from the dirt of the road. Coloured plastic is well known in the art, as are luminous fills, etc. The number of colours is not limited to three, as two or four colours might work equally well.

[281 In a further embodiment, the stud can be coated in rubber at the top, so that the colours are invisible until the coating rubber begins to wear down.

[29] The pellets are preferably welded or otherwise joined together. Many welding methods may be used, such as ultrasonic welding, friction welding, vibration welding hot plate welding, hot gas welding, resistive and implant welding, and laser welding.

[30] With regard to friction welding, this would be done in stages, and each pellet would be friction welded to the next.

With reference to Figure la, the friction welding has been done at junctions 115. Then the three pellets are assembled into the stud via an interference fit. Methods for friction welding and interference fitting are well known in the art.

[31] Ultra sonic welding is well known in the art. This method uses mechanical vibrations to form a joint. The vibrations are of high frequency. The parts to be assembled are held together under pressure between the oscillating horn and an immobile anvil and are subjected to ultrasonic vibrations of frequency 20 to 40 KHz at right angles to the contact area.

Alternating high frequency stresses generate heat at joint interface to produce a good quality weld. The adjoining surfaces of pellets lii, 112 and 113 are welded together at junctions 115.

They also may be further welded into the stud.

[32] There are many ways that the studs could be installed into the tire. In one embodiment, a small pilot hole is first bored into the tyre, followed by the insertion of the stud.

Methods for inserting studs into tyre like materials are well known in the art and should not be seen as limited to any particular method. As mentioned above, the shape of the stud is designed to help the stud be retained in the tyre.

[33) In one embodiment, it is anticipated that the studs and pellets on the tyre would work well within a set of regulations requiring road users to install studs on their new tyres.

[34] In this embodiment, a new tyre is assessed for its characteristics. These characteristics might include features such as the make of tyre, width of tyre, tyre composition, depth and width of tread and grooves, ply, shoulder, etc. Appropriate positioning for the studs is determined based on the assessed characteristics.

[35] In an example, a customer may decide to buy a new tire and have tread wear indicators fitted. A staff member takes the tire and places it in a tread wear indicator fitting machine. The staff member sets the machine to the specific tyre configuration, via a database. The machine aligns itself, relative to the tyre, and inserts a number of tread wear indicators across the tyre width. The machine then rotates the tyre and repeats the insertion of tread wear indicators.

[36] The stud position is, in one embodiment, according to a general theme. One example of a general theme is shown in Fig 2.

Four studs, of which outermost pellet 113 of each is visible, are positioned in a substantially parallel line, along the tire width, and four such sets are applied, at each of four circumferential locations around the tyre, such as at 90 degree intervals around the tyre. This theme allows the user, other road users, and law enforcement officials and devices to easily see the condition of the tyre, from any viewing angle. It also discloses if the wear is equal across the width of the tyre.

According to this theme, more or less than four sets of four studs could be used, according to need and tyre size. Other examples of general themes could alternatively be applied, such as the studs arranged in zigzags around the tyre.

[37] The invention has been described with many specificities which should not be construed as limiting the invention in any way.

Claims

Claims I claim: 1. Tread wear indicators for a tyre, comprising a plurality of studs, for insertion into the tyre, and three different coloured pellets for each stud, wherein said three pellets are welded to one another in a colour configuration, and to the interior of said stud, wherein said stud has an exterior comprising a substantially flat base, and corrugated sides, wherein said corrugated sides comprise slanted portions and horizontal portions, wherein said slanted portions allow said stud to be easily inserted in said tyre, and wherein said horizontal portions help said stud be retained in the tyre.
2. The tread wear indicators of claim 1 wherein said colour configuration comprises red, yellow and green in the order from innermost pellet to outermost pellet.
3. The tread wear indicators of claim 1 wherein said stud and said pellets are made of plastic.
4. The tread wear indicators of claim 1 wherein four studs are applied in a parallel line, along the width of the tyre in each of four circumferential locations around the tyre.
5. The tread wear indicators of claim 1 further comprising a database for tyre characteristics of different types of tyres, and means for inserting and aligning said studs in a tyre according to tyre characteristics of the tyre, read from said database.
6. The tread wear indicators of claim 1 wherein said coloured pellets are of even thickness.
7. The tread wear indicators of claim 6 further comprising means for boring a pilot hole in said tyre in the positions where the tread wear indicators are to be inserted.
8. The tread wear indicoators of claim 1 wherein said pellets and studs are friction welded together.