Patent Description:
Studs for winter tires have been known for decades and have helped to significantly improve traction characteristics on snow and particularly ice-covered surfaces to improve the grip of the tire to icy roads and other icy pavements. However, conventional tire studs also have some drawbacks which have limited their use in winter tires. For example, conventional tire studs typically have a body which is made of a metal material, such as aluminum, and have a pin extending from the body for ensuring non-skid behavior of the tire on icy roads. Recently studs based on polymeric material have been developed, an example of a polymer stud is given in <CIT>.

In any case, the use of polymeric material in tire studs is not very well-established and there is still a need for improvement in stud design. In particular, there is always a need to improve stud retention in the tire tread for polymeric stud body. In this regard, with the tire stud of the present invention, it was found that by adapting the design of the polymeric stud body of a tire stud it was possible to improve its durability compared to tire studs known in the art.

Further tire studs with a stud body having anchoring means to improve stud retention in the tread portion are known from <CIT>, <CIT> and <CIT>. However these documents fail to disclose a polymeric material of the stud body.

The invention relates to a tire stud in accordance with claim <NUM>, to a tire in accordance with claim <NUM> and to a method in accordance with claim <NUM>.

In a preferred aspect of the invention, a tire stud is provided comprising a stud body comprising at least one polymer and a pin; wherein the stud body comprises a top portion PT, an intermediate portion P, and a bottom portion PB, PT being adjacent to PI being adjacent to PB; and wherein, in PB, the tire stud further comprises n foldable anchoring elements EB(n), with n = <NUM> or more, attached to the stud body, wherein each foldable anchoring element extends axially outward, i.e. away, from the stud body.

Due to the one or more foldable anchoring elements of the tire stud, the tire studs according to the present invention are better retained in the borehole of the tread of the pneumatic tire increasing greatly the durability of the tire stud and their efficacy for winter, snow and/or ice pneumatic tires.

Furthermore, the present invention relates to a pneumatic tire comprising at least one tire stud according to the present invention.

In the context of the present invention, the expression "each foldable or bendable anchoring element extends radially outward from the stud body" means that said element extends at an angle > <NUM>°, preferably in the range of from <NUM>° to <NUM>°, more preferably in the range of from <NUM>° to <NUM>°, outward from the stud body.

In the context of the present invention, the term "inserted position" for the tire stud refers to the position of the tire stud once it is embedded in a pneumatic tire (tread).

In the context of the present invention, the term "pre-insertion position" or "expansion position" for the tire stud refers to the position of the tire stud as produced and not embedded into a pneumatic tire (tread).

In the context of the present invention, the term "radial" or "radial direction" refers to a length or distance that is parallel to the axis from the top of the pin of the tire stud to the bottom of the stud body. Hence, the radial direction is parallel to the axis of rotation or to the symmetry axis of the tire stud, if any. "Radial" also refers to the direction when the tire stud is inserted into the tread of a tire, i.e., in accordance with its intended use. Hence, a "radial" direction of the tire stud is also a radial direction of the tire.

In the context of the present invention, the term "axial" or "axial direction" refers to a length or distance that is perpendicular to the radial direction. "Axial" also refers to the direction when the tire stud is inserted into the tread of a tire, i.e., in accordance with its intended use. Hence, an "axial" direction of the tire stud is also an axial direction of the tire, i.e., parallel to the axis of rotation of the tire.

A tire stud is disclosed comprising a stud body comprising at least one polymer and a pin; wherein the stud body comprises a top portion PT, an intermediate portion PI and a bottom portion PB, PT being adjacent to PI being adjacent to PB; and wherein, in PB, the tire stud further comprises n foldable anchoring elements EB(n), with n = <NUM> or more, attached to the stud body, wherein each foldable anchoring element extends axially outward from the stud body.

Preferably, each anchoring element is foldable at the junction between said anchoring element and the stud body.

Preferably, n = <NUM> or more, such that the tire stud comprises two or more foldable anchoring elements EB(n).

Preferably, when n = <NUM> or more, the junction between the anchoring elements and the stud body is located in the upper part of the bottom portion PB of the stud body.

Preferably, when n = <NUM> or more, in PB, the foldable anchoring elements are positioned in the same horizontal plan.

Preferably, n is in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>.

Preferably, in PB, the tire stud comprises three foldable anchoring elements EB(<NUM>), EB(<NUM>) and EB(<NUM>) or four foldable anchoring elements EB(<NUM>), EB(<NUM>), EB(<NUM>) and EB(<NUM>), which are spaced from one another, more preferably equally spaced from one another.

Preferably, when n = <NUM> or more, at least one anchoring element EB(<NUM>) of the n foldable anchoring elements EB(n), more preferably each element EB(n), has a length LEB in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, the length LEB being the axial distance between the most outward end point of the element and the end point of the element in contact with the stud body.

Preferably, when n = <NUM> or more, one foldable anchoring element, more preferably each of the n foldable anchoring elements EB(n) has a maximal width WEB in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>.

Preferably, when n = <NUM> or more, the foldable anchoring elements EB(n) have a substantially rectangular shape, substantially triangular shape, half-moon shape or trapezoidal shape, more preferably a substantially rectangular shape.

Preferably, when n = <NUM> or more, the n foldable anchoring elements are foldable anchoring wings.

Preferably, when n = <NUM> or more, in PI, the tire stud further comprises m foldable anchoring elements EI(m), with m = <NUM> or more, attached to the stud body, wherein each foldable anchoring element EI(m) extends axially outward from the stud body.

Preferably, m is in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>.

Preferably, in PT, there is no foldable anchoring element.

Preferably, in PI, there is no foldable anchoring element.

Alternatively, preferably, in PI, the tire stud comprises three foldable anchoring elements EI(<NUM>), EI(<NUM>) and EI(<NUM>) or four foldable anchoring elements EI(<NUM>), EI(<NUM>), EI(<NUM>) and EI(<NUM>) which are spaced from one another, more preferably equally spaced from one another.

Preferably, in PI, the foldable anchoring elements EI(m) are positioned in the same horizontal plan.

Preferably, the foldable anchoring elements EI(m) of PI are located in a plan parallel to the plan, wherein the foldable anchoring elements EB(n) of PB are located, with n = <NUM> or more.

Preferably, in PI, at least one anchoring element, more preferably each element, of the m foldable anchoring elements EI(m) has a length LEI in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, the length LEI being the axial distance between the most outward end point of the element and the end point of the element in contact with the stud body. Preferably, LEI = LEB.

Preferably, in PI, one foldable anchoring element, more preferably each element, of the m foldable anchoring elements EI(m) has a maximal width WEI in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>. Preferably, WEI = WEB.

Preferably, in PI, the foldable anchoring elements EI(m) have a substantially rectangular shape, substantially triangular shape, half-moon shape or trapezoidal shape, more preferably a substantially rectangular shape. More preferably, the foldable anchoring elements EI(m) have the same shape as the foldable anchoring elements EB(n).

Preferably, the m foldable anchoring elements EI(m) are foldable anchoring wings.

In the context of the present invention, preferably, in PB, the foldable anchoring elements EB(n) comprise at least one polymer, more preferably the anchoring elements are made of the same at least one polymer of the stud body.

Preferably, the foldable anchoring elements EB(n) are at least partially flexible. Preferably, the foldable anchoring elements EI(m) are at least partially flexible.

Preferably, in PI, the foldable anchoring elements EI(m) comprise at least one polymer, more preferably the anchoring elements are made of the same at least one polymer of the stud body.

Preferably, all foldable anchoring elements of the tire stud are made of the same material as the material used for the stud body.

Preferably, the tire stud has an inserted position and a pre-insertion position, wherein, when n = <NUM> or more, at the inserted position, the foldable anchoring elements are folded and adjacent to the stud body, and, at the pre-insertion position, the foldable anchoring elements are unfolded at an angle, in the range of from <NUM> to <NUM>°, more preferably in the range of from <NUM> to <NUM>°, outward from the stud body.

As an alternative to the above, preferably, n = <NUM> such that the tire stud comprises one foldable anchoring element EB(<NUM>).

Preferably, when n = <NUM>, the foldable anchoring element is a foldable anchoring collar.

Preferably, when n = <NUM>, the junction between the anchoring element and the stud body is located in the lower part of the bottom portion PB of the stud body.

Preferably, the foldable anchoring collar has a maximal width is in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>.

Preferably, the foldable anchoring collar has a regular circular shape or an irregular circular shape. When the collar has an irregular circular shape, it means that it can comprise one or more protrusions. Preferably, the foldable anchoring collar is attached all around the stud body and is foldable at the junction of the stud body and the collar.

Preferably, the foldable anchoring collar comprises at least one polymer, more preferably the foldable anchoring collar is made of the same at least one polymer of the stud body.

Preferably, the foldable anchoring collar is at least partially flexible.

Preferably, the foldable anchoring collar is made of the same material as the material used for the stud body.

Preferably, the tire stud has an inserted position and a pre-insertion position, wherein, when n = <NUM>, at the inserted position, the foldable anchoring element is folded at an angle in the range of from <NUM> to <NUM>°, more preferably in the range of from <NUM> to <NUM>°, outward from the stud body, and, at the pre-insertion position, the foldable anchoring element is unfolded at an angle, of more than <NUM>°, more preferably in the range of from <NUM> to <NUM>°, more preferably in the range of from <NUM> to <NUM>°, outward from the stud body.

In the context of the present invention, the stud body may have any shapes. Examples of shapes are illustrated in the figures of the present invention.

Preferably, the at least one polymer comprised in the stud body is selected from the group consisting of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polypropylene (PP), polyethylene (PE), polycarbonate (PC), polysulfone (PSU), polyetherimide (PEI), polyphenylene sulfone (PPSU), polyarylamide (PARA), polyamine (PA), syndiotactic <NUM>,<NUM>-polybutadiene (SPBD), phenolic resin, melamine resin, epoxy resin, benzoxazine-based polymer, cyanate ester resin, polyurethane (PU), polyacrylic ester, a polyimide and a mixture of two or more thereof.

In the context of the present invention, SPBD offers the advantage of becoming securely bound to the rubber of the tire tread. It is believed that the syndiotactic <NUM>,<NUM>-polybutadiene (SPBD) co-cures with the rubber of the tire tread during the curing of the tire, resulting in a strong adhesion between the SPBD and the tire tread. SPBD can be prepared in an inert organic solvent utilizing the technique described in <CIT> or in an aqueous medium utilizing the process described in <CIT>. The latter more specifically reveals a process for producing polybutadiene composed essentially of SPBD comprising the steps of:.

Preferably, the SPBD utilized for preparing the stud body comprised in the tire stud of the present invention has a melting point of <NUM> or less, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>. The melting points referred to herein are the minimum endotherm values determined from DSC ( differential scanning calorimetry) curves.

It is conceivable that the stud body comprises a blend of polymers, including SPDB (from <NUM> to <NUM> weight - percent based on the weight of the blend) and at least one rubber (from <NUM> to <NUM> weight - percent based on the weight of the blend) which is curable with the SPBD. The rubber component used in such blends can be virtually any type of elastomer which contains unsaturation that allows for sulfur curing. Typically, the elastomer will be one or more polydiene rubbers. Some representative examples of suitable polydiene rubbers include cis-<NUM>,<NUM>-polybutadiene, natural rubber, synthetic polyisoprene, styrene butadiene rubber, EPDM (ethylenepropylene- diene monomer) rubbers, isoprene-butadiene rubbers, and styreneisoprene-butadiene rubbers. In many cases it will be desirable to utilize a combination of diene rubbers in the blend. For instance, the rubber portion of the blend can be a combination of chlorobutyl rubber, natural rubber, and EPDM rubber. Preferably, a the rubber component comprises from <NUM> to <NUM> weight - percent, more preferably from <NUM> to <NUM> weight - percent, chlorobutyl rubber, from <NUM> to <NUM> weight - percent, more preferably from <NUM> to <NUM> weight - percent, natural rubber, and from <NUM> to <NUM> weight - percent, more preferably from <NUM> to <NUM> weight - percent, EPDM, the weight percent being based on the weight of the rubber component.

In the context of the present invention, it is believed that the inclusion of high content of SPBD in the stud body results in better adhesion, abrasion, and tear resistance for the cured material. High contents of SPBD also result in increased green strength and stiffness. Additionally, it is believed that the use of high levels of SPBD reduces green tack which makes handling. However, the incorporation of large amounts of SPBD into the blend also results in reduced flexibility and modulus. Accordingly, for the best balance of overall properties, the blend utilized preferably contains from <NUM> to <NUM> weight - percent SPBD and from <NUM> to <NUM> weight - percent co-curable rubbers. More preferably, the blend in the stud body contains from <NUM> to <NUM> weight - percent SPBD and from <NUM> to <NUM> weight - percent of the elastomeric component.

The SPBD used for preparing the blend can be in powder or pellet form. The SPBD powder or pellets can be mixed into the rubber component utilizing standard mixing techniques. However, the mixing is normally carried out at a temperature which is at least as high as the melting point of the SPBD being utilized. During the mixing procedure, the SPBD powder pellets are fluxed into the rubber with additional desired compounding ingredients. Such mixing is typically carried out in a Banbury mixer, a mill mixer or in some other suitable type of mixing device.

Such blends of SPBD and rubber component may further contain other standard rubber chemicals. For instance, such blends may contain sulfur and at least one desired colorant or pigment, e.g. titanium dioxide can be of interest as it can be used as pigment and filler. They will also typically contain other rubber chemicals, such as antioxidants, accelerators, oils, and waxes in conventional amounts. The typical content of sulfur and first and secondary accelerators are disclosed in <CIT>which is incorporated herein.

Alternatively or in addition to SPBD, other polymers, such as those disclosed in the foregoing, can be used for the stud body.

Optionally, the stud body is reinforced with one or more fibers. Preferably, the one or more fibers are glass fibers, woven fibers or staple fibers. The stud body may further comprise one or more of a pigment and a dye.

Preferably, the at least one polymer comprised in the n foldable anchoring elements EB(n) of the tire stud is selected from the group consisting of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polypropylene (PP), polyethylene (PE), polycarbonate (PC), polysulfone (PSU), polyetherimide (PEI), polyphenylene sulfone (PPSU), polyarylamide (PARA), polyamine (PA), syndiotactic <NUM>,<NUM>-polybutadiene (SPBD), phenolic resin, melamine resin, epoxy resin, benzoxazine-based polymer, cyanate ester resin, polyurethane (PU), polyacrylic ester, a polyimide and a mixture of two or more thereof.

Preferably, the at least one polymer comprised in the m foldable anchoring elements EI(n) of the tire stud is selected from the group consisting of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polypropylene (PP), polyethylene (PE), polycarbonate (PC), polysulfone (PSU), polyetherimide (PEI), polyphenylene sulfone (PPSU), polyarylamide (PARA), polyamine (PA), syndiotactic <NUM>,<NUM>-polybutadiene (SPBD), phenolic resin, melamine resin, epoxy resin, benzoxazine-based polymer, cyanate ester resin, polyurethane (PU), polyacrylic ester, a polyimide and a mixture of two or more thereof.

Optionally, the foldable anchoring element(s) of the tire stud is(are) reinforced with one or more fibers. Preferably, the one or more fibers are glass fibers, woven fibers or staple fibers. The foldable anchoring element(s) of the tire stud may further comprise one or more of a pigment and a dye.

Preferably, the stud body and the n foldable anchoring elements EB(n) of the tire stud are made of the same material.

Preferably, the stud body and the m foldable anchoring elements EI(m) of the tire stud are made of the same material.

Preferably, the stud body and the n foldable anchoring elements are produced in one piece.

Preferably, the stud body and the n foldable anchoring elements are formed/produced by injection molding or the like. Indeed, thanks to the stiffness and elasticity of the used polymer, the element(s) can be folded and unfolded at the junction stud body/element.

Preferably, the stud body and any foldable anchoring elements of the tire stud are produced in one piece. Preferably, the stud body and any foldable anchoring elements of the tire stud are formed/produced by injection molding or the like.

Preferably, the stud body presents one or more constrictions, wherein the width of the stud body in the one or more constriction areas is lower than the width of the stud body in the non-constriction areas.

Preferably, in the intermediate portion PI, the stud body presents one or more constrictions, wherein the width of the stud body in the one or more constriction areas is lower than the width of the stud body in the non-constriction areas.

Preferably, the stud body presents one constriction.

Alternatively, preferably, the stud body presents a constriction at the upper part of PI and a constriction at the lower part of PI with a bead between said constrictions. This is in particular illustrated in <FIG>.

Preferably, in PI, the tire stud further comprises m foldable anchoring elements EI(m), with m = <NUM> or more, attached to the stud body, wherein each of said foldable anchoring elements extend axially, i.e. away, outward from the stud body.

Preferably, the width of the bead is equal to from <NUM> to <NUM> percent, more preferably from <NUM> to <NUM> percent, more preferably from <NUM> to <NUM> percent, of the maximal width of the stud body in the top portion.

Preferably, the width of the bead is equal to from <NUM> to <NUM> percent, more preferably from <NUM> to <NUM> percent, more preferably from <NUM> to <NUM> percent, of the maximal width of the stud body in the bottom portion.

Preferably, in PI, the foldable anchoring elements EI(m) are attached to the bead of the stud body.

Preferably, the foldable anchoring elements EI(m) in PI are as defined in the foregoing.

Alternatively, preferably, the stud body presents no constriction. This is in particular illustrated in <FIG>, <FIG> and <FIG>, wherein there is also no anchoring elements in PI and PT.

In the context of the present invention, it is preferred that the top portion PT, the intermediate portion PI and the bottom portion PB of the stud body have the same or different shapes.

The present invention further relates to a pneumatic tire comprising at least one tire stud according to the present invention.

Preferably, the pneumatic tire further comprises a tread, wherein the tread comprises the at least one tire stud, more preferably a plurality of tire studs according to the present invention, embedded therein. The pin comprised in the at least one stud extends out of the tread.

Preferably, the pneumatic tire is a winter, snow and/or ice pneumatic tire.

The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The tire stud of any one of embodiments <NUM> to <NUM>", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The tire stud of any one of embodiments <NUM>, <NUM> and <NUM>". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

According to embodiment <NUM> of the present invention relating to a tire stud, the tire stud comprises.

The tire stud of embodiment <NUM>, wherein each anchoring element is foldable at the junction between said anchoring element and the stud body.

The tire stud of embodiment <NUM> or <NUM>, wherein, in PB, the tire stud comprises three foldable anchoring elements EB(<NUM>), EB(<NUM>) and EB(<NUM>) or four foldable anchoring elements EB(<NUM>), EB(<NUM>), EB(<NUM>) and EB(<NUM>), which are spaced from one another, preferably equally spaced from one another.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, when n = <NUM> or more, at least one anchoring element EB(<NUM>) of the n foldable anchoring elements WB(n), preferably each element EB(n), has a length LEB in the range of from <NUM> to <NUM>, preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>, the length LEB being the axial distance between the most outward end point of the element and the end point of the element in contact with the stud body.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, when n = <NUM> or more, one foldable anchoring element, preferably each, of the n foldable anchoring elements EB(n) has a maximal width WEB in the range of from <NUM> to <NUM>, preferably in the range of from <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, when n = <NUM> or more, the foldable anchoring element EB(n) have a substantially rectangular shape, substantially triangular shape, half-moon shape, or trapezoidal shape, preferably a substantially rectangular shape.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, when n = <NUM> or more, the n foldable anchoring elements are foldable anchoring wings.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, when n = <NUM> or more, in PI, the tire stud further comprises m foldable anchoring elements EI(m), with m = <NUM> or more, attached to the stud body, wherein each foldable anchoring element EI(m) extends axially outward away from the stud body.

The tire stud of embodiment <NUM>, wherein, in PI, the tire stud comprises three foldable anchoring elements EI(<NUM>), EI(<NUM>) and EI(<NUM>) or four foldable anchoring elements EI(<NUM>), EI(<NUM>), EI(<NUM>) and EI(<NUM>) which are spaced from one another, preferably equally spaced from one another.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, in PB, the foldable anchoring elements comprise at least one polymer, preferably the anchoring elements are made of the same at least one polymer of the stud body.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein the tire stud has an inserted position and a pre-insertion position, wherein, when n = <NUM> or more, at the inserted position, the foldable anchoring elements are folded and adjacent to the stud body and, at the pre-insertion position, the foldable anchoring elements are unfolded at an angle, in the range of from <NUM> to <NUM>°, preferably in the range of from <NUM> to <NUM>°, outward from the stud body.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, when n = <NUM>, the foldable anchoring element is a foldable anchoring collar, preferably wherein the tire stud has an inserted position and a pre-insertion position, wherein, when n = <NUM>, at the inserted position, the foldable anchoring element is folded at an angle in the range of from <NUM> to <NUM>°, more preferably in the range of from <NUM> to <NUM>°, outward from the stud body, and, at the pre-insertion position, the foldable anchoring element is unfolded at an angle, of more than <NUM>°, more preferably in the range of from <NUM> to <NUM> °, more preferably in the range of from <NUM> to <NUM>°, outward from the stud body.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein the at least one polymer comprised in the stud body is selected from the group consisting of polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyphenyl ether (PPE), polypropylene (PP), polyethylene (PE), polycarbonate (PC), polysulfone (PSU), polyetherimide (PEI), polyphenylene sulfone (PPSU), polyarylamide (PARA), polyamine (PA), syndiotactic <NUM>,<NUM>-polybutadiene (SPBD), phenolic resin, melamine resin, epoxy resin, benzoxazine-based polymer, cyanate ester resin, polyurethane (PU), polyacrylic ester, a polyimide and a mixture of two or more thereof.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein the stud body and the n foldable anchoring elements are produced in one piece, preferably by injection molding.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein, in the intermediate portion PI, the stud body presents one or more constrictions, wherein the width of the stud body in the one or more constriction areas is lower than the width of the stud body in the non-constriction areas.

The tire stud of embodiment <NUM>, wherein the stud body presents a constriction at the upper part of PI and a constriction at the lower part of PI with a bead between said constrictions, wherein, in PI, the tire stud further comprises m foldable anchoring elements WI(m), with m = <NUM> or more, attached to the stud body, wherein each of said foldable anchoring elements extend axially outward, i.e. away, from the stud body.

The tire stud of any one of embodiments <NUM> to <NUM>, wherein the stud body presents no constriction.

A pneumatic tire comprising at least one tire stud according to any one of embodiments <NUM> to <NUM>.

The pneumatic tire of embodiment <NUM>, further comprising a tread, wherein the tread comprises the at least one tire stud, more preferably a plurality of tire studs according to any one of embodiments <NUM> to <NUM>, embedded therein, wherein the pin comprised in the at least one stud extends out of the tread.

The pneumatic tire of embodiment <NUM> or <NUM>, being a winter, snow and/or ice pneumatic tire.

<FIG> is a schematic cross-sectional view of the assembly of a tire stud according to a preferred embodiment of the present invention into a pneumatic tire tread. In particular, <FIG> shows the tire stud <NUM> according to the present invention in different positions A, B and C during its assembly into a pneumatic tire tread <NUM>. Position A is the pre-insertion or expansion position, at which the anchoring wings EB(<NUM>), EB(<NUM>) numbered as <NUM> a and 4b are unfolded at an angle of about <NUM>° outward from the stud body. Position B is the pre-insertion or expansion position, at which the anchoring wings are unfolded at an angle of about <NUM>° outward from the stud body and position C is the inserted position at which the anchoring wings EB(<NUM>), EB(<NUM>) numbered as 4a, 4b are folded and adjacent to the stud body and the tire stud <NUM> is in the tread <NUM>, with the pin <NUM> extending out of the tread <NUM>. The tire stud <NUM> comprises a stud body <NUM> comprising at least one polymer as defined in the foregoing, the stud body comprising a top portion PT, an intermediate portion PI and a bottom portion PB. The tire stud <NUM> further comprises a pin <NUM> which is inserted at the top of <NUM>. In PB, the tire stud <NUM> further comprises three foldable anchoring wings EB(<NUM>), EB(<NUM>) numbered as 4a, 4b and 4c and EB(<NUM>) not shown in <FIG> which have the same dimensions and are spaced equally from one another in the same horizontal plan. The material of the wings is preferably the same material used for the stud body.

<FIG> is a schematic top view of a tire stud according to a preferred embodiment of the present invention, namely the tire stud <NUM> illustrated in <FIG>. In <FIG>, the three foldable wings EB(<NUM>), EB(<NUM>) and EB(<NUM>), numbered as 4a, 4b and 4c, are visible.

<FIG> is a three-dimensional schematic view of a tire stud according to another preferred embodiment of the present invention. The tire stud <NUM> according to the present invention comprises a stud body <NUM> comprising at least one polymer as defined in the foregoing, the stud body comprising a top portion PT, an intermediate portion PI and a bottom portion PB. The tire stud <NUM> further comprises a pin <NUM> which is inserted at the top of <NUM>. In PB, the tire stud <NUM> further comprises four foldable anchoring wings EB(<NUM>), EB(<NUM>), EB(<NUM>) and EB(<NUM>), numbered as 14a, 14b, 14c and 14d, which have the same dimensions and are spaced equally from one another in the same horizontal plan. The material of the wings EB(<NUM>), EB(<NUM>), EB(<NUM>) and EB(<NUM>) is preferably the same material used for the stud body. In PI, the stud body comprises two constrictions <NUM>, <NUM> forming a bead <NUM> between said constrictions and four foldable anchoring wings EI(<NUM>), EI(<NUM>), EI(<NUM>) and EI(<NUM>), numbered as 114a, 114b, 114c and 114d. <FIG> shows the tire stud in a pre-insertion position.

<FIG> is schematic top view of a tire stud according to a preferred embodiment of the present invention, namely the tire stud <NUM> illustrated in <FIG>. In <FIG>, only the four foldable wings EI(<NUM>), EI(<NUM>), EI(<NUM>) and EI(<NUM>), numbered as 114a, 114b, 114c and 114d, are visible. <NUM> represents the top of the stud body.

Claim 1:
A tire stud, the tire stud (<NUM>) having a stud body (<NUM>) comprising or consisting of at least one polymer and a pin (<NUM>), wherein the stud body (<NUM>) comprises a radially outer top portion (PT), an intermediate portion (PI) and a radially inward bottom portion (PB), the outer portion (PT) being radially adjacent the intermediate portion (PI) and the intermediate portion (PI) being adjacent to the inward bottom portion (PB), and wherein, in the radially inward bottom portion (PB), the tire stud (<NUM>) further comprises at least one foldable or bendable anchoring element (4a, 4b, 4c) attached to the stud body (<NUM>), said anchoring element (4a, 4b, 4c) extending away from the stud body (<NUM>).