POLYMER STUD AND A TIRE COMPRISING A POLYMER STUD

Abstract

In a first aspect of the invention, an anti-skid tire stud is provided, the stud having a body made of polymer-based material, wherein the stud body comprises a top portion comprising polymer-based material having a first color, a bottom portion comprising polymer-based material having a second color, and wherein the stud further comprises a pin extending out of the top portion for contacting the road. In a second aspect of the invention, the invention relates to a tire comprising such anti-skid tire studs.

Claims

1. An anti-skid tire stud which is comprised of a stud body and a pin, wherein the stud body is comprised of a top portion which is comprised of a polymeric material having a first color and a bottom portion which is comprised of a polymeric material having a second color which is different from the first color, and wherein the pin extends out of the top portion.

2. The anti-skid tire stud of claim 1, wherein the stud has an elongated shape with two ends wherein the top portion is arranged at a first end and the bottom portion is arranged at the second end.

3. The anti-skid tire stud of claim 1, wherein the pin extends into the stud body in the direction of the bottom portion, and wherein the pin extends more than 5% of the length of the stud body out of the stud.

4. The anti-skid tire stud of claim 1, wherein the bottom portion comprises a circumferential projection which is adapted for securing the stud in a hollow space for receiving the stud in a tire tread.

5. The anti-skid tire stud of claim 1, wherein the stud comprises an intermediate portion between the top portion and the bottom portion, and wherein the intermediate portion has a smaller diameter than the maximum diameter of at least one of the top portion and the bottom portion.

6. The anti-skid tire stud of claim 1, wherein the stud body comprises an intermediate portion between the top portion and the bottom portion, the intermediate portion comprising a polymer-based material having a third color, and wherein the intermediate portion extends to a laterally outer surface of the stud such that the laterally outer surface of the intermediate portion has the third color.

7. The anti-skid tire stud of claim 1, wherein the pin has at least one projection for securing the pin in the body of the stud, and wherein the projection is located at an end of the pin anchored in the body of the stud.

8. The anti-skid tire stud of claim 1, wherein the top portion has a maximum diameter which is at least 5% larger than the diameter of an intermediate portion arranged between the top portion and the bottom portion, and wherein a maximum diameter of the bottom portion is at least 10% larger than the maximum diameter of the top portion.

9. The anti-skid tire stud of claim 1, wherein the top portion and the bottom portion extend to laterally outer surfaces of the stud such that the laterally outer surface of the top portion has the first color and the laterally outer surface of the bottom portion has the second color.

10. The anti-skid tire stud of claim 1, wherein the pin is comprised of a metal or a ceramic material and is optionally made of tungsten carbide.

11. The anti-skid tire stud of claim 1, wherein the polymeric material is a thermoplastic material, and wherein the pin is comprised of tungsten carbide.

12. The anti-skid tire stud of claim 1, wherein the polymeric material is colored with one or more of pigments or dyes.

13. The anti-skid tire stud of claim 1, wherein the top portion has a green color or a black color, and wherein the bottom portion has a red color.

14. The anti-skid tire stud of claim 1, wherein the stud has an intermediate portion between the top portion and the bottom portion having an orange color or yellow color.

15. The anti-skid tire stud of claim 1, wherein the pin extends in parallel to a length of the stud along a central axis of the stud, wherein the pin has a polygonal cross section or a bow-shaped cross section, and extends over at least a third of the length of the stud.

16. The anti-skid tire stud of claim 1, wherein the pin extends through the entire top portion into the bottom portion.

17. The anti-skid tire stud of claim 1, further comprising an intermediate portion between the top portion and the bottom portion, the intermediate portion having a section having a third colo, wherein the pin extends through the top portion having the first color and the intermediate portion having the third color into a part of the bottom portion having the second color, and wherein at least 5% of the pin extends into the bottom portion having the second color.

18. A tire comprising tread blocks, wherein a plurality of said tread blocks include the anti-skid tire studs as specified in claim 1.

19. The tire of claim 18, wherein a top surface of the top portion of the stud is essentially flush with the tread block surface and wherein the pin extends in an outer radial direction of the tire.

20. The tire of claim 18, wherein the pin extends through the top portion into the bottom portion and wherein the colors of the top portion and the bottom portion indicate the wear of the stud as the stud and the tread blocks wear upon driving.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The structure, operation, and advantages of the invention will become more apparent upon contemplation of the following description taken in conjunction with the accompanying drawings, wherein:

[0052] FIG. 1 represents a schematic side view of an example tire stud;

[0053] FIG. 2 represents a schematic top view of the tire stud of FIG. 1;

[0054] FIG. 3 represents a schematic side view of another example tire stud;

[0055] FIG. 4 represents a schematic top view of the tire stud shown in FIG. 3;

[0056] FIG. 5 is a schematic cross section through a tire's crown portion including a tread with tread blocks comprising studs in accordance with an example of the invention;

[0057] FIG. 6 is a schematic cross section of an essentially unworn tread block with two adjacent circumferential tread grooves, with the tread block comprising a stud in accordance with an example of the invention;

[0058] FIG. 7 is a schematic cross section of the tread block of FIG. 6 but in a further worn state; and

[0059] FIG. 8 is a schematic cross section of the tread block shown in FIG. 6 and

[0060] FIG. 7 but in a further worn state than in FIG. 6 and FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

[0061] FIG. 1 shows a schematic side view of a first example of a tire stud 3 in accordance with the invention. The stud 3 comprises an elongated pin 33 extending out of the top portion 31 of the stud 3 and extending also through the top portion 31 into a bottom portion 32 as shown by the dashed lines. In general, the stud 3 is supposed to be mounted in the tread of a tire, in particular into ribs and/or tread blocks of a tire such that the top portion 31 is mounted radially outward of the bottom portion 32. In other words, the bottom portion 32 is located radially inwards of the top portion 31 when the stud 3 is mounted in the tire. The bottom portion 32 or the top portion 31 may each comprise at least one protrusion or projection helping to anchor the stud 3 into a mounting hole in a tire tread. Preferably, the bottom portion 32 has a smaller diameter (measured perpendicular to the extension of the pin 33) at an upper end 34 of the bottom portion 32 than in a lower region of the bottom portion 32. Moreover, the maximum diameter of the bottom portion 32 is larger than the maximum diameter of the top portion 31, wherein the diameter of the latter portion 31 is again preferably larger than a diameter of the upper end region 34 of the bottom portion 32. The top portion 31 comprises a first polymer having a first color and the bottom portion 32 comprises a second polymer having a second color, different from the first one. Typically, the top portion 31 could have black or green color whereas the bottom portion 32 may have a red color.

[0062] FIG. 2 is a top view of the stud 3 shown in FIG. 1. In this example, the pin 33 has a hexagonal shape which may improve the anchoring of the pin 33 in the polymer material and/or may also increase the road grip, or in other words the non-skid behavior. Moreover, the bottom portion 32 protrudes or projects beyond the top portion 31 perpendicular to the pin 33. While it may be desirable that the projection of the bottom portion 32 is larger than the projection of the top portion 31, the top portion 31 may essentially extend as far as the bottom portion 32 away from the center line of the pin 33 (the central axis of the pin 33 in parallel to the length of the pin 33).

[0063] FIG. 3 shows a side view of a second example of a tire stud 3. Stud 3 is similar to stud 3 of FIGS. 1 and 2, with the main difference that the stud 3 comprises an intermediate portion 35 arranged between the top portion 31 and the upper end region 34 of the bottom portion 32, wherein the intermediate portion comprises a polymer-based material having a color different from the first and second color mentioned above. Typically, the color of the intermediate portion 35 could be yellow or orange.

[0064] In general, the used polymer-based material may be essentially the same in the whole stud body, with the only difference of including different dyes for achieving different visual appearance in terms of color.

[0065] FIG. 4 is a top view of the stud 3 wherein the top view is the same as for stud 3 as shown in FIG. 2. The same reference signs as in FIG. 2 have been used for stud 3 where applicable.

[0066] FIG. 5 is a schematic partial cross section of a tire 1, showing essentially the tire crown area. For the sake of simplification bead areas of the tire 1 are not shown herein as those are not crucial for the present invention. The person skilled in the art knows how to design such bead areas of the tire 1. As shown in FIG. 5, the tire 1 has also sidewalls 2, a tread 10, belt plies 11, a carcass ply 9 and an inner liner 13. Moreover, the tire tread 10 has four circumferential grooves 15 as well as ribs or tread blocks 14 adjacent said grooves 15. A plurality of tread blocks 14 have studs 3, 3 with the radial top portion of the studs aligned (flush) with the radially outer surface of the tread blocks 14. In this example, the tire 1 is essentially unworn or new. The pins of the studs 3, 3 protrude out of the tread 10, and the tread blocks 14 respectively, such that they increase the non-skid properties of the tire 1, in particular on icy roads or ice.

[0067] FIG. 6 is a schematic cross section of a portion of the tread 10, showing a tread block 14 and two adjacent grooves 15. The tread block 14 comprises a stud 3, with its upper edge of its top portion 31 aligned with the radial outer edge of the tread block 14. Similar to the situation shown in FIG. 5, stud 3 and tread block 14 are still essentially unworn, with the tread block 14 having a radial height d.sub.n. The radial height of the tread block 14 is measured from the bottom of an adjacent groove 15 to the radially outer edge of the tread block 14. The pin 33 has also its initial or original length and extends through the top and intermediate portions into the bottom portion of the stud 3. The user would see a black or green color of the stud 3 when looking at the stud 3 located in the tread 10.

[0068] It is emphasized that the tread blocks shown in the examples of the present invention may have in general also other shapes than shown. In particular, when looking at the tread, said blocks do not need to have rectangular shapes, they may have other polygonal shapes or for instance other shapes known in the art of winter tire treads.

[0069] FIG. 7 shows the tread 10 in a worn state. The tread block 14 has only the radial height d.sub.w which is smaller than the height of the tread block d.sub.n in the unworn state. Consequently, the top portion of the stud 3 is worn and has in this example completely disappeared such that only the intermediate portion 35 is left at the radially outer surface of the tread block 14. The length of the pin 33 has decreased as well. As in aluminum studs, the pin 33 wears at a similar speed as the stud 3 such that the pin 33 extends from the tread block 14 into the outer radial direction of the tire 1. According to the situation depicted in FIG. 7, visual inspection would show a yellow or orange color of the stud 3 when looking at the worn tread 10.

[0070] In FIG. 8, the tread 10 and the particular tread block 14 are further worn compared to the situation depicted in FIG. 7. Tread block height d.sub.r is smaller than tread block height d.sub.w shown in FIG. 7. As a consequence, also the intermediate portion 35 has disappeared due to wear and the only remaining body portion of the stud 3 is the bottom portion 32. The pin 33 has only a relatively small length of extension into stud 3, respectively the bottom portion left. This may mean that stud 3 or its pin 33 may lose its function or may be lost soon. As a warning sign, the stud 3 could visually appear red at the tread surface.

[0071] Variations in the present invention are possible in light of the provided description. The illustrations and corresponding descriptions are not intended to restrict or limit the scope of the appended claims in any way. While certain representative embodiments, examples and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the invention. It is, therefore, to be understood that changes may be made in the particular example embodiments described which will be within scope of the invention as defined by the following appended claims.