Patent Description:
A tread of a known pneumatic tyre is indicated in <FIG>. A pneumatic tire is known to include a tread which has circumferential and transversal grooves on its outer surface, said grooves defining a number of tread blocks. The tread is meant for a rolling contact against a ground surface, such as road. The grooves are meant for draining water and/or slush that is possibly located on the ground surface away from the tread, so that the contact between the tread and the ground surface is as good and consistent as possible. Referring to <FIG>, some tires are provided in the tread with a number of sipes (S<NUM>, S<NUM>, S<NUM>, S<NUM>) at various angles with respect to a motion direction of the tire. The sipes not only serve a better tire-ground contact in the rain, but also improve traction, braking and lateral stability on snow by trapping snow as well as providing more gripping edges. The sipes also make the rubber material to deform more easily, in effect making the tire appear softer. This also improves friction. A purpose of the invention is to improve grip, stability, and handling of the tire.

Lamella plates are commonly used in the manufacturing process of a pneumatic tire for making said sipes. The lamella plate is included in a mould, in which the tire is made. After vulcanizing the tire, the tire is removed from the mould, and the lamella plates are removed from the tread. The locations where the lamella plates were arranged define the sipes of the tread. A purpose of the invention is to present a lamella plate that can be used to manufacture the tire with improved grip.

For example, the document <CIT> discloses a tire having a sipe having a first surface area and an opposite facing second surface area, and each surface area has a plurality of recesses or protrusions. A blade (i.e. a lamella plate) insertable into a cast for the purpose of forming the sipe is also disclosed. The document <CIT> discloses blade (i.e. a lamella plate) for forming a sipe. To affect rigidity, in the blade uneven parts are formed on a blade frame and lateral protrusion parts are formed on lower portions of the sipe-forming uneven parts. The document <CIT> discloses a sipe having a crank portion, which is cranked so as to protrude in a trapezoidal shape in the middle of the tire radial direction, is provided on one end of a sipe in a block. The crank portion is formed in such a way that the protruding portion of the crank shape becomes smaller gradually from the one end of the sipe toward the tire width direction. The document <CIT> discloses sipes formed as sipe grooves. Protrusions are formed at sipe groove. Some protrusions protrude in reverse direction so that a rubber volume becomes substantially equal at both sides of the sipe groove.

For improved traction, the opposing walls of a sipes should lock to each other properly particularly during breaking and acceleration and in presence of lateral forces. While some degree of locking is known to occur in some special sipes, the locking of the sipes is not always optimal. An object of the invention is to improve the properties of a tire provided with sipes in the tread blocks so that the sipes can work more efficiently in the sense of improved gripping, improved stability, and improved handling, because of the more efficient locking of the sipe walls. A tire according to the invention is defined in more specific terms in claim <NUM>. The dependent claims <NUM> to <NUM> define preferred embodiments of the tire and other parts of specification define embodiments of the tire.

It is also an object of the invention to provide a lamella plate that is able to make the sipe according to the present invention. A lamella plate according to the invention is defined in more specific terms in claim <NUM>. The dependent claims <NUM> to <NUM> define preferred embodiments of the lamella plate and other parts of specification define embodiments of the lamella plate.

The embodiments relate to a tire having tread blocks and a lamella plate for manufacturing a tire. The tire is preferably a pneumatic tire. At least some tread blocks are provided with sipes. To improve locking of sipe walls, opposite walls of a sipe, preferably opposite walls of many sipes, are provided with an indentation and a protrusion. Herein the term sipe refers to a narrow groove provided in a tread block of a tire. In between two parallel sipes, a lamella may be arranged. The term lamella refers to a narrow piece of tread block material in between two sipes. As an example, <FIG> shows a lamella LAM in between the sipes S<NUM> and S<NUM>. A lamella plate is a plate that is usable for forming a sipe in a moulding process. When a lamella plate is embedded to uncured rubber, and removed therefrom after curing the rubber, the sipe is formed.

In the present case, novel features of the tire <NUM> are derivable from the shape of the lamella plate <NUM> used for forming the sipe(s). Therefore, embodiments of a lamella plate <NUM> are defined first. As well known, because of the moulding process, a shape of the sipe formed by the lamella plate is geometrically congruent with the part of the lamella plate that is arranged in the tread of the tire during moulding.

<FIG> shows, in a side view, a lamella plate <NUM> for forming a sipe to a tire. Somewhat similar lamella plate <NUM> is shown in <FIG> in a perspective view; in <FIG> in a side view; and in <FIG> in a top view. <FIG> shows the cross section A-A of <FIG>. Thus, referring to <FIG>, and <FIG>, the lamella plate <NUM> comprises a first surface <NUM> and a second surface that is opposite <NUM> to the first surface <NUM>. The first surface <NUM> is provided with a first primary plate indentation PI<NUM> and a first primary plate protrusion PP<NUM>. The first primary plate indentation PI<NUM> may have been made to a plate by pressing the indentation PI<NUM> thereto. Alternatively, the plate <NUM> may have been made by additive manufacturing. When manufacturing the tire <NUM>, a part of the lamella plate <NUM> is arranged in a tread <NUM> of the tire such that the direction SR of <FIG> is parallel to a radial direction SR of the tire (see <FIG>) at the point of the lamella plate <NUM>. The directions SS and ST in <FIG> are orthogonal to SR, and ST is a direction of a thickness of the lamella plate. This concerns also <FIG>.

As detailed above, a purpose of the invention is to lock walls of a sipe to each other during braking, acceleration, and/or driving on a curve. Braking and acceleration cause circumferential forces to the tire, and driving on a curve causes lateral forces to the tire. In this way, the locking of the walls of the sipes improves grip, stability, and handling of the tire. Therefore, and referring to <FIG>, the second surface <NUM> is provided with a second primary plate protrusion PP<NUM> that is opposite to the first primary plate indentation PI<NUM>. The second surface <NUM> is also provided with a second primary plate indentation PI<NUM> that is opposite to the first primary plate protrusion PP<NUM>.

In the lamella plate <NUM>, the first surface <NUM> defines a first primary lamella plate surface LPS<NUM>. In the embodiments shown e.g. in <FIG> and <FIG>, the first primary lamella plate surface LPS<NUM> has the shape of a planar surface. However, in the embodiment shown in <FIG>, the first primary lamella plate surface LPS<NUM> has the shape of a curved surface. The first surface <NUM> defines the first primary lamella plate surface LPS<NUM> such that the first surface <NUM> comprises the first primary lamella plate surface LPS<NUM>.

The first primary plate protrusion PP<NUM> protrudes from the first primary lamella plate surface LPS<NUM> and the first primary plate indentation PI<NUM> descends into the first primary lamella plate surface LPS<NUM>. Preferably, an area of the first primary lamella plate surface LPS<NUM> is at least <NUM> %, more preferably at least <NUM> %, of an area of the first primary plate protrusion PP<NUM>. Preferably, an area of the first primary lamella plate surface LPS<NUM> is at least <NUM> %, more preferably at least <NUM> %, of an area of the first primary plate indentation PI<NUM>.

In the lamella plate <NUM>, the second surface <NUM> defines a second primary lamella plate surface LPS<NUM>. In the embodiments shown e.g. in <FIG> and <FIG>, the second primary lamella plate surface LPS<NUM> has the shape of a planar surface. However, in the embodiment shown in <FIG>, the second primary lamella plate surface LPS<NUM> has the shape of a curved surface.

The second surface <NUM> defines the second primary lamella plate surface LPS<NUM> such that the second surface <NUM> comprises the second primary lamella plate surface LPS<NUM>.

The second primary plate protrusion PP<NUM> protrudes from the second primary lamella plate surface LPS<NUM> and the second primary plate indentation PI<NUM> descends into the second primary lamella plate surface LPS<NUM>.

Concerning the both the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM>, both these surfaces may be planar surfaces. In the alternative, both these surfaces may be curved surfaces. Herein a curved surface refers to a planar surface that is obtainable by bending a plane about (i) an axis, (ii) axes that are parallel with each other and lying on only one side of the planar surface, or (iii) (iii,a) at least one primary axis, which is/are parallel with a primary direction and lying on a same side of the plane and (iii,b) at least one secondary axis, which is/are parallel with a secondary direction that is different from the primary direction, the secondary axes/axis lying mutually on a same side of the plane. The secondary axes may be arranged on a different side than the primary axes. Preferably, the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM> are planar or curved such that they are obtainable from a planar surface by bending about only one axis or by bending about only such axes that are parallel with each other and that are on a same side of the planar surface. Even more preferably, the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM> are planar or curved such that they are obtainable from a planar surface by bending about one axis or by bending about only such axes that are parallel with each other such that a radius of curvature about the axis/axes is constant throughout the lamella plate surfaces LPS<NUM>, LPS<NUM>.

It is noted that the lamella plate may be, but need not be, manufactured from a planar plate. As an alternative, a lamella plate may be manufactured using an additive manufacturing technique (including e.g. rapid prototyping and various sintering techniques). Thus, the shape of the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM> as disclosed above does not restrict the manufacturing method to a method comprising bending a plate.

In <FIG>, the lamella plate surfaces LPS<NUM>, LPS<NUM>, LPS<NUM>, and LPS<NUM> have such a curved shape that is obtainable from a planar surface by bending about only one axis, and the radius of curvature is constant. Naturally, when forming the plate, a planar plate may be bent in multiple process steps, but the resulting plate has a shape of being bent about only one axis such that the resulting radius of curvature is constant. Preferably, the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM>, are either planar or curved surfaces in such a way that they are obtainable from a planar surface by bending about only one axis or axes that are parallel with each other. With reference to <FIG>, the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM> may be planar even if the whole surfaces <NUM>, <NUM> are not.

The surfaces <NUM>, <NUM> having both a protrusion and an indentation has the effect that the walls of the sipe manufactured by the lamella plate <NUM> lock to each other well irrespective of the direction of the forces (forward or backward; or transversal forces to left or right). Correspondingly, the sipes function well both during acceleration and braking, and improve handling also when driving on a curve, curved to either direction.

In an embodiment, a thickness of the lamella plate <NUM> is constant at least in the regions defining the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM>. This has the effect that the second primary plate protrusion PP<NUM>, which is opposite to the first primary plate indentation PI<NUM>, is geometrically congruent with the first primary plate indentation PI<NUM>. Moreover, the second primary plate indentation PI<NUM>, which is opposite to the first primary plate protrusion PP<NUM>, is geometrically congruent with the first primary plate protrusion PP<NUM>. This improves the locking of the sipe walls to each other. More preferably, a thickness of the lamella plate <NUM> is constant at least in the regions defining the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, the second primary plate indentation PI<NUM>, the first primary lamella plate surface LPS<NUM>, and the second primary lamella plate surface LPS<NUM>. Naturally, the thickness of the whole lamella plate <NUM> may be constant. This is beneficial for manufacturing reasons. The thickness of the lamella plate <NUM> may be e.g. <NUM> to <NUM>; preferably <NUM> to <NUM>.

It has been found that the locking functions particularly well when the first primary plate indentation PI<NUM> is arranged close to the first primary plate protrusion PP<NUM>. They may even contact each other, as shown in <FIG>. Therefore, in an embodiment, a minimum distance dPI between the first primary plate protrusion PP<NUM> and the first primary plate indentation PI<NUM> is at most <NUM>. The minimum distance dPI is preferably at most equal to a thickness of the lamella plate <NUM>. The minimum distance dPI may be at most <NUM> or zero. These distances have the effect that the projection functions together with the closely neighbouring indentation in this way improving the locking effect. In an embodiment, the minimum distance dPI is arranged in a direction that is parallel to a projection line PR. The projection line PR is a projection of a of a line that remains between a centre of the first primary plate protrusion PP<NUM> and a centre of the first primary plate indentation PI<NUM>, the projection being a normal projection to the first primary lamella plate surface LPS<NUM>. Such a projection line PR is shown e.g. in <FIG>. The minimum distance dPI may be zero as in <FIG>. However, the protrusion PP<NUM> and the indentation PI<NUM> need not contact each other, whereby the distance may be greater, as shown in <FIG>. It is noted that <FIG> shows a protrusion and an indentation that do not incline towards each other, as detailed below. A somewhat similar shape is shown also in <FIG>.

Referring to <FIG>, preferably, the first primary plate protrusion PP<NUM> is symmetric with the second primary plate protrusion PP<NUM> about an axis AXS. More precisely, in an embodiment, the first primary plate protrusion PP<NUM> is symmetric with the second primary plate protrusion PP<NUM> about an axis AXS such that, upon a rotation of <NUM> degrees about the axis AXS of symmetry, the first primary plate protrusion PP<NUM> coincides with the second primary plate protrusion PP<NUM> (unrotated). Herein the angle of <NUM> degrees is given with an accuracy of only two significant figures, because the curved surface (see <FIG>) may have the effect that the angle is not precisely <NUM> degrees.

Having this type of symmetry in the lamella plate <NUM> relates to the effect of locking the sipes in all directions that are parallel to the tread <NUM>.

In case the first primary plate protrusion PP<NUM> is symmetric with the second primary plate protrusion PP<NUM> about an axis AXS, preferably, the axis AXS of symmetry is parallel or at least substantially parallel to a direction that, in the tire, is a radial direction. More specifically, preferably, [i] a direction of the axis AXS is parallel to a direction dR that is directed from a lower edge <NUM> of the lamella plate <NUM> to an opposite upper edge <NUM> (see <FIG>) or [ii] a direction of the axis AXS forms first angles (α<NUM>, α<NUM>) with a direction dR that is directed from a lower edge <NUM> of the lamella plate <NUM> to an opposite upper edge, wherein a minimum α<NUM> of the first angles (α<NUM>, α<NUM>) is at most <NUM> degrees (see <FIG>). The direction dR is directed from the lower edge <NUM> of the lamella plate <NUM> to the opposite upper edge <NUM> along shortest possible path. A hole <NUM> may be arranged closer to the upper edge <NUM> than the lower edge <NUM> (see <FIG>).

As for other characteristics of preferable shapes for the indentation PI<NUM> and protrusion PP<NUM>, it is noted that the first primary plate protrusion PP<NUM> and the first primary plate indentation PI<NUM> define a projection line PR (see <FIG>) as defined above.

Preferably, the indentation PI<NUM> and protrusion PP<NUM> are arranged side-by-side rather than on top of each other. This improves handling of the tire under transversal load, e.g. driving in a curve. Referring to <FIG>, preferably, a direction of the projection line PR forms second angles β<NUM>, β<NUM> with the direction dR, wherein a minimum β<NUM> of the second angles β<NUM>, β<NUM> is at least <NUM> degrees. Referring to <FIG>, the minimum β<NUM> of the second angles β<NUM>, β<NUM> may be <NUM> degrees (one significant figure).

Referring to <FIG>, according to the invention, the first primary plate protrusion PP<NUM> is antisymmetric about all such planes LAS that have a normal that is parallel to the projection line PR. In other words, the first primary plate protrusion PP<NUM> is not symmetric about any such plane LAS that has a normal that is parallel to the projection line PR. It has been found that this improves handling of the tire under transversal load, e.g. driving in a curve. For similar reasons, in an embodiment, the first primary plate indentation PI<NUM> is antisymmetric about all such planes LAS that have a normal that is parallel to the projection line PR.

Referring to <FIG>, in an embodiment, the first primary plate protrusion PP<NUM> is symmetric about a plane LS. As shown in <FIG>, a normal of the plane LS of symmetry may be parallel to the direction dR as defined above. However, it need not be parallel, as shown in <FIG>. In an embodiment, the first primary plate indentation PI<NUM> is symmetric about a plane. It may be symmetric about the same plane LS. This type of symmetry has the effect that an outer part of the tread locks to a neighbouring sipe as well as an inner part of the tread. This has beneficial properties for handling the tire. More preferably, the first primary plate protrusion PP<NUM> is symmetric about a plane LS and the first primary plate indentation PI<NUM> is symmetric about the plane LS. The plane LS of symmetry may comprise the projection line PR as defined above and a normal of the primary lamella plate surface LPS<NUM> as defined above.

It has also been found that the locking improves when there is a smooth transition from the protruding region of the first surface <NUM> to the declining region of the first surface <NUM>. Therefore, and with reference to <FIG>, in an embodiment a part of a surface of the first primary plate protrusion PP<NUM> is inclined such that a height hP<NUM>(r) of the first primary plate protrusion PP<NUM>, measured from the first primary lamella plate surface LPS<NUM>, decreases towards the first primary plate indentation PI<NUM>. Herein the height hP<NUM>(r) refers to the height as measured in a location r. Thus, the height hP<NUM>(r) decreases as the location r moves towards the first primary plate indentation PI<NUM> as shown in <FIG>. In contrast, the height hP<NUM>(r) could decrease to zero abruptly (within the limits of manufacturing tolerances of the lamella plate <NUM>) as indicated in <FIG> and <FIG>. A maximum of the height hP<NUM>(r) of the first primary plate protrusion PP<NUM> is, in an embodiment, from <NUM> to <NUM>.

When the height hP<NUM>(r) of the first primary plate protrusion PP<NUM> decreases towards the first primary plate indentation PI<NUM> the height hP<NUM>(r) preferably decreases such that a first inclination IN1 (see <FIG> and <FIG>) defines a first inclination angle γ1 less than <NUM> degrees. The first inclination angle γ1 is an angle that remains between (i) a primary first line that remains between the point r of maximum height of the height hP<NUM>(r) of the first primary plate protrusion PP<NUM> and a center of the projection line PR as defined above and (ii) a secondary first line that is projection of the primary first line, the projection being a normal projection to the first primary lamella plate surface LPS<NUM>. Reference is made to <FIG>. It has been found that if the first inclination angle γ1 was more, the locking effect would not be as good. Clearly, by the nature of the protrusion, the first inclination angle γ1 is greater than zero. Preferably, the first inclination angle γ1 is at least <NUM> degrees. The first inclination angle γ1 is shown in <FIG>.

As for an abrupt decrement of the height, an abrupt decrement can be quantified by a third inclination angle (not shown), which is for the abrupt change almost <NUM> degrees, e.g. at least <NUM> degrees.

Preferably, also the inclination of different sides of the protrusion PP<NUM> makes it antisymmetric as indicated above. Thus, in a preferable embodiment (see <FIG>), a first part R1 of a surface of the first primary plate protrusion PP<NUM> is inclined such that a height hP<NUM>(r) of the first primary plate protrusion PP<NUM> decreases from a maximal height towards the first primary plate indentation PI<NUM> by a first inclination IN1. As previously, the height hP<NUM>(r) is defined from the first primary lamella plate surface LPS<NUM>. Moreover, a second part R2 of the surface of the first primary plate protrusion PP<NUM> is inclined such that the height hP<NUM>(r) of the first primary plate protrusion PP<NUM> decreases from the maximal height away from the first primary plate indentation PI<NUM> by a second inclination IN2. Moreover, the second inclination IN2 is different from the first inclination IN1. Preferably, the second inclination IN2 is steeper than the first inclination IN1, as depicted in <FIG>. This applies also to the second primary plate protrusion PP<NUM> mutatis mutandis (see <FIG>).

The second inclination IN2 defines a defines a second inclination angle γ2. The second inclination angle γ2 is an angle that remains between (i) a primary second line that remains between the point r of maximum height of the height hP<NUM>(r) of the first primary plate protrusion PP<NUM> and a point that is on a line that comprises the projection line PR the point being located at such a boundary of the first primary plate protrusion PP<NUM> that is opposite to a center of the projection line PR and (ii) a secondary second line that is projection of the primary second line, the projection being a normal projection to the first primary lamella plate surface LPS<NUM>. Reference is made to <FIG>. Preferably, the second inclination angle γ2 is greater than the first inclination angle γ1. Preferably, also the second inclination is not abrupt. Thus, preferably, the second inclination angle γ2 is less than <NUM> degrees. The second inclination angle γ2 is shown in <FIG>.

Preferably a height of the lamella plate (i.e. a distance between the lower edge <NUM> and the upper edge <NUM>) is more or less constant at least for the part that comprises the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM>. However, in case the lamella plate is for manufacturing a sipe for a shoulder are of the tire, the height of the lamella plate at one end may be less that the height of the lamella plate at another, opposite, end.

The height of the lamella plate <NUM> may decrease locally e.g. because of a taper <NUM> (see <FIG>). Such a taper may be arranged according to needs. A taper <NUM> may, e.g., ease bending of a plate. In a preferable embodiment, the lower edge <NUM> extends without a taper <NUM> for at least a portion overlapping each one of the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM>. Herein the term overlapping refers to overlapping in the direction dR as defined above. Moreover, the lower edge <NUM> is configured to be inserted into a tread <NUM> of a tire <NUM>, while typically the opposite upper edge <NUM> is not configured to be inserted in to the tread at all. As two examples, the neither the taper <NUM> of <FIG> nor the taper <NUM> of <FIG> overlaps any protrusion or indentation in the direction dR.

Herein the term "taper" refers to a groove limited by the lamella plate, the groove extending in the thickness of the lamella plate. Thus, the taper tapers the lamella plate, i.e. reduces locally its height.

The lamella plate <NUM> may also comprise a taper <NUM>, e.g. when it has more protrusions. Referring to <FIG>, <FIG>, <FIG>, and <FIG>, in an embodiment the lower edge <NUM> comprises a taper <NUM>. However as shown in the figures, preferably the taper <NUM> does not overlap any one of the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM>. Referring to <FIG>, preferably, a length Lftb of the portion of the lower edge <NUM> that is free from a taper <NUM> is at most <NUM> % greater than a length Lppi of projection of the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM> to the lower edge <NUM>. The lengths Lppi and Lftb may be substantially equal, as readable from <FIG>.

Preferably, at least a part of the first primary lamella plate surface LPS<NUM> is arranged between the upper edge <NUM> of the lamella plate <NUM> and both of the first primary plate indentation PI<NUM> and the first primary plate protrusion PP<NUM>. This has the effect that a reasonably large portion of a wall of a sipe that is the outermost part of the tread has the shape of a plane or a curved surface. This improves traction of the tire, sine the edges of such sipes have an improved grip on the road.

Preferably, also at least a part of the first primary lamella plate surface LPS<NUM> is arranged between the lower edge <NUM> and both of the first primary plate indentation PI<NUM> and the first primary plate protrusion PP<NUM>.

The projection line PR as defined above defines a direction SS of a length of the lamella plate <NUM>, at least at the location of the projection PR line. Referring to <FIG>, in an embodiment, a length RPI<NUM> of the first primary plate indentation PI<NUM>, as measured in the direction SS of a length of the lamella plate <NUM> is greater than a width WPI<NUM> of the first primary plate indentation PI<NUM>, as measured in a direction that is perpendicular to the direction SS of the length of the lamella plate and perpendicular to a norm of the first primary lamella plate surface LPS<NUM>. This has the effect that the first primary plate indentation PI<NUM> can be made relatively large, which improves the locking of the sipe walls. Preferably, the length RPI<NUM> of the first primary plate indentation PI<NUM> is at least <NUM> % greater than the width WPI<NUM> of the first primary plate indentation PI<NUM>. This applies also to the first primary plate indentation PP<NUM>. Thus, in an embodiment, a length RPP<NUM> of the first primary plate protrusion PP<NUM> is greater than a width WPP<NUM> of the first primary plate protrusion PI<NUM>, wherein the direction of length and width are defined as in the context of the indentation PI<NUM>. Preferably, the length RPP<NUM> of the first primary plate protrusion PP<NUM> is at least <NUM> % greater than the width WPP<NUM> of the first primary plate protrusion PP<NUM>.

In an embodiment, the length RPI<NUM> of the first primary plate indentation PI<NUM> is from <NUM> to <NUM>, such as from <NUM> to <NUM>. In an embodiment, the length RPP<NUM> of the first primary plate protrusion PP<NUM> is from <NUM> to <NUM>, such as from <NUM> to <NUM>. In an embodiment, the length RPP<NUM> of the first primary plate protrusion PP<NUM> is equal to the length RPI<NUM> of the first primary plate indentation PI<NUM>. In an embodiment, the width WPP<NUM> of the first primary plate protrusion PP<NUM> is equal to the width WPI<NUM> of the first primary plate indentation PI<NUM>.

In an embodiment, a maximum of the width WPI<NUM> of the first primary plate indentation PI<NUM> is from <NUM> to <NUM>. In an embodiment, a maximum of the width WPP<NUM> of the first primary plate protrusion PP<NUM> is from <NUM> to <NUM>.

As for the width WPI<NUM> of the first primary plate indentation PI<NUM>, preferably the first primary plate indentation PI<NUM> is narrower closer to the protrusion PP<NUM> than away from it. More specifically, and referring to <FIG>, in an embodiment, the width WPI<NUM>(r) of the primary plate indentation PI<NUM> decreases towards the first primary plate protrusion PP<NUM>. Referring to <FIG>, the width WPI<NUM>(r<NUM>) of the first primary plate indentation PI<NUM> at a first location r<NUM>, which is further away from the first primary plate protrusion PP<NUM> than a second location r<NUM>, is greater than the width WPI<NUM>(r<NUM>) of the primary plate indentation PI<NUM> at the second location r<NUM>.

In an embodiment, this applies also to the first primary plate protrusion PP<NUM> mutatis mutandis. Thus, in an embodiment, a width WPP<NUM>(r) of the primary plate protrusion PP<NUM> decreases towards the first primary plate indentation PI<NUM>. Referring to <FIG>, the width WPP<NUM>(r<NUM>) of the first primary plate protrusion PP<NUM> at a third location r<NUM>, which is further away from the first primary plate indentation PI<NUM> than a fourth location r<NUM>, is greater than the width WPP<NUM>(r<NUM>) of the first primary plate protrusion PP<NUM> at the fourth location r<NUM>.

Referring to <FIG>, <FIG>, and <FIG>, the whole lamella plate <NUM>, excluding the protrusions and the indentations, need not have a shape of a plane or a curved surface. As indicated in <FIG>, <FIG>, <FIG>, the lamella plate <NUM> may comprise multiple bend points BP. In this case, the first primary lamella plate surface LPS<NUM> and the first secondary lamella plate surface LPS<NUM> may be arranged between two neighbouring bend points, and the protrusions PP<NUM>, PP<NUM> may protrude therefrom and the indentations PI<NUM>, PI<NUM> may descend thereto, as indicated in <FIG> and <FIG>. Moreover, lengthwise, the protrusions PP<NUM>, PP<NUM> and the indentations PI<NUM>, PI<NUM> may use the whole length between the bend points BP. However, they need not. In this sense, the bend point BP may affect the length of the lower edge <NUM> in a similar way as a taper <NUM>. Reference is made also to <FIG> and what has been said about the length of the lower edge <NUM>. Thus, in an embodiment the lower edge <NUM> comprises a bend point BP. However, preferably the bend point BP does not overlap any one of the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM>. Preferably, a length Lftb of the portion of the lower edge <NUM> that is free from a bend point BP is at most <NUM> % greater than a length Lppi of projection of the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM> to the lower edge <NUM>. The lengths Lppi and Lftb may be substantially equal.

In particular, if the lower edge <NUM> comprises bend points BP, it may comprise a taper <NUM> that overlaps the first primary plate indentation PI<NUM> or the first primary plate protrusion PP<NUM>. Even in such a case, a length Lftb of the portion of the lower edge <NUM> that is free from a bend point BP is, in an embodiment, at most <NUM> % greater than a length Lppi of projection of the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM> to the lower edge <NUM>. The lengths Lppi and Lftb may be substantially equal.

As indicated in <FIG>, not even a part of the first primary lamella plate surface LPS<NUM> or the first secondary lamella plate surface LPS<NUM> needs to be arranged in between a bend point BP and a the protrusion PP<NUM> or the indentation PI<NUM>. As indicated in <FIG>, in such a case, at least a part of the first primary lamella plate surface LPS<NUM> may be arranged between the upper edge <NUM> and the protrusion/indentation and/or between the lower edge <NUM> and the protrusion/indentation.

Referring to <FIG> and <FIG>, the lamella plate <NUM> may comprise another protrusion and indentation. Thus, in an embodiment, the first surface <NUM> is provided with a first secondary plate indentation PI<NUM> and a first secondary plate protrusion PP<NUM>. Correspondingly, the second surface <NUM> is provided with a second secondary plate protrusion PP<NUM> that is opposite to the first secondary plate indentation PI<NUM> and a second secondary plate indentation PI<NUM> that is opposite to the first secondary plate protrusion PP<NUM> (see <FIG>).

Moreover, the first surface <NUM> defines a first secondary lamella plate surface LPS<NUM> having the shape of a planar surface or a curved surface, from which the first secondary plate protrusion PP<NUM> protrudes and into which the first secondary plate indentation PI<NUM> descends. In addition, the second surface <NUM> defines a second secondary lamella plate surface LPS<NUM> having the shape of a planar surface or a curved surface, from which the second secondary plate protrusion PP<NUM> protrudes and into which the second secondary plate indentation PI<NUM> descends. What has been said about the area of the primary lamella plate surface LPS<NUM> applies, mutatis mutandis, to an area of the first secondary lamella plate surface LPS<NUM>.

Referring to <FIG> and <FIG>, both the first primary lamella plate surface LPS<NUM> and the first secondary lamella plate surface LPS<NUM> may be a part of the same planar or curved surface. In a similar manner, both the second primary lamella plate surface LPS<NUM> and second secondary lamella plate surface LPS<NUM> may be a part of the same planar or curved surface. However, referring to <FIG> and <FIG>, they need not be. In the embodiment of <FIG>, the lamella plate <NUM> comprises such bend points that the first primary lamella plate surface LPS<NUM> and the first secondary lamella plate surface LPS<NUM> are not part of the same curved surface in the conventional meaning of the term "curved surface". For a detailed definition of a curved surface, see above wherein the term is defined in connection with the first primary lamella plate surface LPS<NUM> and second primary lamella plate surface LPS<NUM>. In the embodiment of <FIG>, the lamella plate <NUM> comprises such bend points that the first primary lamella plate surface LPS<NUM> and the first secondary lamella plate surface LPS<NUM> are planar, but not part of the same plane.

The embodiment of <FIG> shows a taper <NUM> that is arranged at a location L<NUM>. The embodiment of <FIG> shows a bend point BP that is arranged at a location L<NUM>. As indicated in these figures, the location L12 of the taper <NUM> or bend point BP does not overlap a protrusion or an indentation in the meaning discussed above. In contrast, the location L<NUM> of the bend point BP or the taper <NUM> is arranged between [A] that one of the first secondary plate indentation PI<NUM> and the first secondary plate protrusion PP<NUM> that is closer to the first primary plate indentation PI<NUM> and [B] that one of the first primary plate indentation PI<NUM> and the first primary plate protrusion PP<NUM> that is closer to the first secondary plate indentation PI<NUM>. However, in addition, the plate may comprise taper that overlaps a protrusion or an indentation in the meaning discussed above. However, preferably, a lamella plate does not comprise a taper that would overlap a protrusion or an indentation in the meaning discussed above.

Referring to <FIG>, if the lamella plate comprises multiple protrusions/indentations, they are preferably arranged such that a direction of a line LLP12 that runs (i) from a centre of a locking form defined by the first primary plate indentation PI<NUM> and a first primary plate protrusion PP<NUM> (ii) to a centre of a locking form defined by the first secondary plate indentation PI<NUM> and the first secondary plate protrusion PP<NUM> is substantially parallel to such a part of the lower edge <NUM> of the lamella plate <NUM> that comprises neither a taper <NUM> nor a bend point BP. In other words, the locking forms are preferably not arranged on top of each other in the direction that would be radial in the corresponding tire. The line LLP12 may be parallel to the such a part of the lower edge <NUM> of the lamella plate <NUM> that comprises neither a taper <NUM> nor a bend point BP. In an embodiment, the smaller of the angles formed by the line LLP12 with such a part of the lower edge <NUM> of the lamella plate <NUM> that comprises neither a taper <NUM> nor a bend point BP is at most <NUM> degrees.

Moreover, preferably the protrusions PP<NUM>, PP<NUM> and the indentations PI<NUM> and PI<NUM> are arranged subsequently such that a protrusion is only arranged between two indentations and vice versa as in the Figures. Therefore, in an embodiment, [i] provided that a distance between the first primary plate indentation PI<NUM> and the first secondary plate indentation PI<NUM> is smaller than a distance between the first primary plate protrusion PP<NUM> and the first secondary plate indentation PI<NUM>, a distance between the first primary plate indentation PI<NUM> and the first secondary plate protrusion PP<NUM> is smaller than a distance between the first primary plate indentation PI<NUM> and the first secondary plate indentation PI<NUM>, and [ii] otherwise, a distance between the first primary plate protrusion PP<NUM> and the first secondary plate indentation PI<NUM> is smaller than a distance between the first primary plate protrusion PP<NUM> and the first secondary plate protrusion PP<NUM>. However, the protrusions PP<NUM> and PP<NUM> may be arranged without any indentation in between them and/or the indentations PI<NUM> and PI<NUM> may be arranged without any protrusion in between them (not shown).

The lamella plate <NUM> as described above may be used to form a sipe of a tire <NUM>. Multiple lamella plates may be used to form multiple sipes to a tread block or a sipe to multiple tread blocks or multiple sipes to multiple tread blocks, which is the most common way for making the sipes.

<FIG> shows a tire <NUM> comprising a tread <NUM>. The tread <NUM> is formed of multiple tread blocks forming an arrangement <NUM> of tread blocks. The tire <NUM> is configured to form a rolling contact against a base <NUM> such as a road. Referring to <FIG> the arrangement <NUM> of tread blocks comprises a first tread block TB<NUM> and a second tread block TB<NUM>. In general, the tread blocks define a groove <NUM> (and also other grooves) which are configured to guide water and slush away from a contact area of the tire <NUM>. Thus, the first tread block TB<NUM> is separated from the second tread block TB<NUM> (and another tread block TB<NUM>, TB<NUM>) by a portion of the groove <NUM>. <FIG> shows half of a cross section of a tire <NUM> and indicates the radial direction SR and the axial direction, i.e. the transversal direction (AX, ST) of the tire. The axial direction AX forms an axis of rotation of the tire <NUM>.

The tread of the tire is formed of multiple tread blocks, including a first tread block TB<NUM> and a second tread block TB<NUM>. Each tread block may comprise a number of sipes, such as a primary sipe and a secondary sipe. Thus e.g. a first tread block TB<NUM> may limit a primary first sipe S<NUM> and a secondary first sipe S<NUM>, the "first" referring to an index of the tread block. Moreover, a (primary, secondary, etc.) sipe is arranged between two walls, the walls being comprised by the (first, second, etc.) tread block. These walls are called as first and second walls. When they concern e.g. a primary first sipe S<NUM>, they are called a first primary first wall W<NUM> and a second primary first wall W<NUM>.

Thus, referring to <FIG> and <FIG>, the first tread block TB<NUM> is provided with sipes, including a primary first sipe S<NUM>. The first tread block TB<NUM> may also limit a secondary first sipe S<NUM>. A lamella LAM is arranged in between the sipes S<NUM> and S<NUM>. The sipes are limited by side walls. Particularly, the primary first sipe S<NUM> is limited by a first primary first wall W<NUM> and an opposite second primary first wall W<NUM> as indicated in <FIG>. These walls are provided in the first tread block TB<NUM>. As readable from above, the walls W<NUM> and W<NUM> have been made by a lamella plate <NUM> as detailed above. Referring to <FIG> and <FIG>, the first primary first wall W<NUM> may have been made by the first surface <NUM> of a lamella plate <NUM>. Correspondingly, referring to <FIG> and <FIG>, the second primary first wall W<NUM> may have been made by the second surface <NUM> of a lamella plate <NUM>. Moreover, outside the location of a lamella plate, the tread block may be integral (i.e. without a sipe). This is shown by the text "no sipe here" in <FIG>. As indicated in <FIG>, in use, an upper edge <NUM> of a lamella plate <NUM> may protrude from the tread <NUM> partly formed by the tread block TB<NUM>. Moreover, a lamella plate <NUM> may be provided with holes <NUM> close to the upper edge <NUM> to help the removal of the lamella plate from the tread <NUM>. Such holes are also shown in <FIG>. Also other embodiments of lamella plates may comprise similar holes <NUM>.

Therefore, referring to <FIG>, the first tread block TB<NUM> comprises a first primary first wall W<NUM> and a second primary first wall W<NUM> such that a primary first sipe S<NUM> is arranged between the first primary first wall W<NUM> and the second primary first wall W<NUM>. Because of the shape of the lamella plate <NUM>, the first primary first wall W<NUM> is provided with a first primary first wall indentation WI<NUM> and first primary first wall protrusion WP<NUM> as shown in <FIG>. These correspond to the first primary plate protrusion PP<NUM> and the first primary plate indentation PI<NUM> of the lamella plate <NUM>, respectively (see <FIG> and <FIG>). Moreover, the second primary first wall W<NUM> is provided with a second primary first wall indentation WI<NUM> and second primary first wall protrusion WP<NUM>. These correspond to the second primary plate protrusion PP<NUM> and the second primary plate indentation PI<NUM> of the lamella plate <NUM>, respectively (see <FIG> and <FIG>).

Moreover, the first primary first wall W<NUM> comprises (i.e. defines) a first primary first wall surface WS<NUM> having the shape of a planar surface or a curved surface, from which the first primary first wall protrusion WP<NUM> protrudes and into which the first primary first wall indentation WI<NUM> descends (see <FIG> and <FIG>). This corresponds to the first primary lamella plate surface LPS<NUM> of the lamella plate <NUM>. The second primary first wall W<NUM> comprises (i.e. defines) a second primary first wall surface WS<NUM> having the shape of a planar surface or a curved surface, from which the second primary first wall protrusion WP<NUM> protrudes and into which the second primary first wall indentation WI<NUM> descends (see <FIG>). This corresponds the second primary lamella plate surface LPS<NUM> of the lamella plate <NUM>.

Moreover, to provide for the locking of the walls W<NUM>, W<NUM> together during braking or acceleration or driving on a curve, the first primary first wall indentation WI<NUM> is geometrically congruent with the second primary first wall protrusion WP<NUM> and the first primary first wall protrusion WP<NUM> is geometrically congruent with the second primary first wall indentation WI<NUM>. They are also arranged such that upon compressing the first primary first wall W<NUM> and the second primary first wall W<NUM> to each other, the second primary first wall protrusion WP<NUM> penetrates into the first primary first wall W<NUM>; and the first primary first wall protrusion WP<NUM> penetrates into the second primary first wall indentation WI<NUM>. This can be achieved at least when a thickness of the lamella plate <NUM> is constant at least in the regions defining the first primary plate indentation PI<NUM>, the first primary plate protrusion PP<NUM>, the second primary plate protrusion PP<NUM>, and the second primary plate indentation PI<NUM>; as discussed above.

As for the term sipe, a width of the sipe corresponds to a thickness of the lamella plate <NUM>. Therefore, in an embodiment, a width of the primary first sipe S<NUM> is from <NUM> to <NUM>, preferably from <NUM> to <NUM>. A readable from <FIG>, the width of the primary first sipe S<NUM> remains between the first primary first wall W<NUM> and the second primary first wall W<NUM>.

As indicated in connection with the lamella plate, in an embodiment, a minimum distance between the first primary first wall indentation WI<NUM> and the first primary first wall protrusion WP<NUM> is at most <NUM>. This corresponds the distance dPI of the lamella plate (see <FIG> and <FIG>). The minimum distance between the first primary first wall indentation WI<NUM> and the first primary first wall protrusion WP<NUM> may be e.g. at most equal the width of the primary first sipe S<NUM>, such as at most <NUM> or zero; i.e. the protrusion WP<NUM> may start at a location where the indentation WI<NUM> ends.

As indicated in connection with the lamella plate, therein the first primary plate protrusion PP<NUM> may be symmetric with the second primary plate protrusion PP<NUM> about an axis AXS. If so, this shows also in the walls W<NUM>, W<NUM> of the first tread block TB<NUM>. Thus and with reference to <FIG>, in an embodiment, a first form FWP that is symmetric with the first primary first wall protrusion WP<NUM> about a first symmetry plane SP<NUM> is symmetric with the first primary first wall indentation WI<NUM> about a second symmetry plane SP<NUM>, the second symmetry plane SP<NUM> being perpendicular to the first symmetry plane SP<NUM>. The first symmetry plane SP<NUM> intersects the second symmetry plane SP<NUM>. The intersection of these planes forms a line, which is parallel to the axis AXS; at least when a part of the lamella plate <NUM> has been inserted into the tread to form the wall protrusions and indentations as detailed above.

Referring to <FIG>, the first primary first wall protrusion WP<NUM> the first primary first wall indentation WI<NUM> of the first primary first wall W<NUM> define a projection line PRW on the wall (i.e. a wall projection line PRW), the projection line PRW on the wall being a projection of a line that remains in between a centre of the first primary first wall protrusion WP<NUM> and a centre of the first primary first wall indentation WI<NUM>, the projection being a normal projection to the first primary first wall surface WS<NUM>.

As shown in <FIG>, the first primary wall W<NUM> is a wall of the first tread block TB<NUM>, which defines a part of the tread <NUM> (see <FIG> and <FIG>). Referring to <FIG>, in an embodiment, the projection line PRW on the wall is parallel to the tread <NUM>. However, it need not be. Considering <FIG> and its effects on the tire <NUM>, in an embodiment, the projection line PRW on the wall forms a minimum angle with the tread <NUM>, and the minimum angle is at most <NUM> degrees. This relates to the angle α<NUM> defined above. It is noted that the tread <NUM> is a surface, and, as conventional, an angle between a line (e.g. PRW) with a plane is defined as the minimum angle between these.

As indicated in connection with the lamella plate, according to the invention, the first primary first wall protrusion WP<NUM> is antisymmetric about all such planes WAS that have a normal that is parallel to the projection line PRW on the wall (i.e. the wall projection line PRW) as defined above. Reference is made to <FIG>. This may apply also to the primary first wall indentation WI<NUM> mutatis mutandis. Therefore, in an embodiment, the first primary first wall indentation WI<NUM> is antisymmetric about all such planes WAS that have a normal that is parallel to the projection line PRW on the wall (i.e. the wall projection line PRW) as defined above.

Referring still to <FIG>, in an embodiment, the first primary first wall protrusion WP<NUM> is symmetric about a plane. In an embodiment, the first primary first wall indentation WI<NUM> is symmetric about another plane or the same plane. In an embodiment, both the first primary first wall protrusion WP<NUM> and the first primary first wall indentation WI<NUM> are symmetric about a plane. Referring to <FIG>, the plane of symmetry may comprise the wall projection line PRW. The plane of symmetry is not shown in <FIG>; instead, reference is made to <FIG> and the plane LS.

Referring particularly to <FIG>, the first primary plate protrusion PP<NUM> may comprise inclined areas. This concerns also the indentations PI<NUM>, PI<NUM> of the lamella plate and, correspondingly, the protrusion PP<NUM> the lamella plate (see <FIG>) mutatis mutandis.

This shows also in the protrusions/indentations of the tire, as reproduced in <FIG>. Referring to <FIG>, in an embodiment, a part of a surface of the first primary first wall protrusion WP<NUM> is inclined such that a height hWP<NUM>(r) of the first primary first wall protrusion WP<NUM>, measured from the first primary first wall surface WS<NUM>, decreases towards the first primary first wall indentation WI<NUM>. A maximum of the height hWP<NUM>(r) of the first primary first wall protrusion WP<NUM> is, in an embodiment, from <NUM> to <NUM>.

Correspondingly, a maximum of a depth of the first primary first wall indentation WI<NUM> is, in an embodiment, from <NUM> to <NUM>. The depth is defined from the first primary first wall surface WS<NUM>.

More preferably, a first part of a surface of the first primary wall protrusion WP<NUM> is inclined such that a height hWP<NUM>(r) of the first primary wall protrusion WP<NUM>, measured from the first primary first wall surface WS<NUM>, decreases from a maximal height towards the first primary first wall indentation WI<NUM> by a third inclination. In addition, a second part of a surface of the first primary wall protrusion WP<NUM> is inclined such that a height hWP<NUM>(r) of the first primary wall protrusion WP<NUM>, measured from the first primary first wall surface WS<NUM>, decreases from a maximal height away from the first primary first wall indentation WI<NUM> by a fourth inclination, wherein the fourth inclination is different from the third inclination. Even more preferably, the fourth inclination is steeper than the third inclination, as depicted in <FIG>. This applies also to the second primary first wall protrusion WP<NUM> of the other wall W<NUM> of the sipe mutatis mutandis.

As readable from above, in an embodiment, the third inclination corresponds to the first inclination IN1 of the lamella plate <NUM>. In an embodiment, the fourth inclination corresponds to the second inclination IN2 of the lamella plate <NUM>. Thus, an inclination angle of the third inclination may be <NUM> to <NUM> degrees as disclosed in connection with the lamella plate and the first inclination angle γ1. Moreover, an inclination angle of the fourth inclination may be greater than the inclination angle of the third inclination and less than <NUM> degrees as disclosed in connection with the lamella plate and the second inclination angle γ2. What has been said about the definition of the inclination angles γ1 and y2 in connection with the lamella plate <NUM> applies to inclination angles of the walls of the sipe mutatis mutandis.

As for preferable measures of the wall protrusion/indentation, in an embodiment and with reference to <FIG>, a length LWP<NUM> of the first primary first wall protrusion WP<NUM>, as measured in the direction of wall projection line PRW is greater than a width of the first primary first wall protrusion WP<NUM>. The width is defined in a direction that is perpendicular to the direction of wall projection line PRW and perpendicular to a norm of the first primary first wall surface WS<NUM>. In <FIG>, the width would be defined in the direction SR which is perpendicular to the tread <NUM>. However, the wall projection line PRW needs not be parallel to the tread <NUM>.

In an embodiment, the length LWP<NUM> of the first primary first wall protrusion WP<NUM> is from <NUM> to <NUM>, such as from <NUM> to <NUM>. Preferably, the length LWP<NUM> of the first primary first wall protrusion WP<NUM> is at least <NUM> % greater than the width of the first primary first wall protrusion WP<NUM>.

Preferably, a width of the first wall protrusion WP<NUM> decreases towards the first primary first wall indentation WI<NUM>, the width of the first wall protrusion WP<NUM> being perpendicular to the length of the first wall protrusion WP<NUM>. Preferably, a width of the first wall indentation WI<NUM> decreases towards the first primary first wall protrusion WP<NUM>, the width of the first wall indentation WI<NUM> being perpendicular to the length of the first wall indentation WI<NUM>.

A maximum of the width of the first wall protrusion WP<NUM> may be <NUM> to <NUM>. A maximum of the width of the first wall indentation WI<NUM> may be <NUM> to <NUM>.

As indicated above, the first primary first wall W<NUM> is configured to lock with the second primary first wall W<NUM>. To this end, the protrusion and indentation, in combination, define a locking shape to enable the locking. More precisely, the first primary first wall indentation WI<NUM> and the first primary first wall protrusion WP<NUM> form a first locking form, which is arranged on the first primary first wall W<NUM>; and the second primary first wall protrusion WP<NUM> and the second primary first wall indentation WI<NUM> form a second locking form, which is arranged on the second primary first wall W<NUM>. The second locking form is geometrically congruent with the first locking form to enable a shape-locking mechanism of the second locking form to the first locking form upon pressing the first primary first wall W<NUM> and the second primary first wall W<NUM> together.

As detailed in connection with a lamella plate <NUM>, the lamella plate <NUM> may comprise a bend point BP or a taper <NUM>. It is noted that the lower edge <NUM> of the lamella plate <NUM> defines a bottom of the sipe, particularly the primary first sipe S<NUM>. If the lower edge <NUM> of the lamella plate <NUM> comprises a taper, the bottom of the primary first sipe S<NUM> comprises a corresponding bottom protrusion (not shown). In line with what has been said about the lamella plate <NUM>, in an embodiment, such a part of a bottom of the primary first sipe S<NUM> that is arranged below the first and second locking forms does not comprise a bend point or a bottom protrusion. If the primary first sipe S<NUM> comprises a bend point and/or a bottom protrusion that/they is/are preferably arranged to another place than below the locking forms defined by the wall protrusions/indentations. However, such a part of a bottom of the primary first sipe S<NUM> that is arranged below the first and second locking forms may comprise a bottom protrusion, even if the first and second locking forms are arranged between two bend points.

A shape of a projection of the first locking form to the first primary first wall surface WS<NUM> may resemble one of the following: an infinity sign, a bowtie, a dog bone, a double ended arrow, a rectangle, and a rounded rectangle. As for the locking form of the sipe of the tire <NUM>, this concerns the locking form formed by first primary first wall indentation WI<NUM> and the first primary first wall protrusion WP<NUM>. As for the locking form of the lamella plates, this concerns the locking form formed by the first primary plate indentation PI<NUM> and the first primary plate protrusion PP<NUM>.

The shape of the first and second locking forms are derivable from the shape of the indentations/protrusions of the lamella plate <NUM>. For example, the <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> show a shape that resembles an infinity sign. <FIG> show a shape that resembles a double ended arrow. <FIG> shows a shape that resembles both a bowtie and a double ended arrow. <FIG> shows a shape that resembles a dog bone. <FIG> show shapes that resemble bowties. <FIG> show shapes that resemble rounded rectangles. <FIG> shows a shape that resembles a rectangle.

However, it has been found that the shape of a rectangle does not function as well as the others. Thus, in an embodiment, a shape of a projection of the first locking form to the first primary first wall surface WS<NUM> does not resemble a rectangle or a rounded rectangle. As for the locking form of the sipe of the tire <NUM>, this concerns the locking form formed by first primary first wall indentation WI<NUM> and the first primary first wall protrusion WP<NUM>. As for the locking form of the lamella plates, this concerns the locking form formed by the first primary plate indentation PI<NUM> and the first primary plate protrusion PP<NUM>, and the shape of the locking form as projected onto the first primary lamella plate surface (LPS<NUM>). Thus, in the embodiment, a shape of a projection of the first locking form to the to the first primary first wall surface WS<NUM> resembles one of the following: an infinity sign, a bowtie, a dog bone, and a double ended arrow.

As discussed above, the primary first sipe S<NUM> is producible in a moulding process by using a lamella plate <NUM> as described above. Referring to <FIG>, in an embodiment, first tread block TB<NUM> comprises a secondary first sipe S<NUM> that is producible in a moulding process by using a lamella plate <NUM> as described above. Referring to <FIG>, in an embodiment, the tire <NUM> comprises a second tread block TB<NUM> that comprises a primary second sipe S<NUM> that is producible in a moulding process by using a lamella plate <NUM> as discussed above. Referring to <FIG>, in an embodiment, the second tread block TB<NUM> comprises a secondary second sipe S<NUM> that is producible in a moulding process by using a lamella plate <NUM> as discussed above.

As an example, the lamella plate may comprise at least two protrusions on each surface <NUM>, <NUM>, as detailed e.g. in <FIG>. Corresponding walls are shown in <FIG>. As detailed in <FIG> in an embodiment, the first primary first wall W<NUM>, which is provided with the first primary first wall indentation WI<NUM> and first primary first wall protrusion WP<NUM>, is further provided with a secondary first primary first wall indentation WI<NUM> and secondary first primary first wall protrusion WP<NUM>. In general, a wall may be provided with a wall protrusion WPijkl wherein l is an index of the tread block, k is an index of a sipe in that tread block, j is an index (<NUM> or <NUM>) of a wall of that sipe, and i is an index of the protrusion. In the above only three indexes are used in case a wall is discussed only in connection with one protrusion, whereby the index i=<NUM> has been omitted. However, there may be several protrusions/indentation on a wall, even if the figures who lamella plates with at most two locking forms. As well known, the number of tread blocks in a tire may be huge (corresponding to index I). Typically a tread block, if comprises sipes, comprises <NUM> to <NUM> sipes, but may comprise also any other number of sipes, such as <NUM> to <NUM> (corresponding to index k). In a similar manner a wall may be provided with a wall indentation WIijkl.

Moreover, the first primary first wall W<NUM> defines a secondary first primary first wall surface WS<NUM> having the shape of a planar surface or a curved surface, from which the secondary first primary first wall protrusion WP<NUM> protrudes and into which the secondary first primary first wall indentation WI<NUM> descends (see <FIG>).

As detailed in <FIG> in an embodiment, the second primary first wall W<NUM>, which is provided with a second primary first wall indentation WI<NUM> and second primary first wall protrusion WP<NUM>, is further provided with a secondary second primary first wall indentation WI<NUM> and secondary second primary first wall protrusion WP<NUM>. Moreover, the second primary first wall W<NUM> defines a secondary second primary first wall surface WS<NUM> having the shape of a planar surface or a curved surface, from which the secondary second primary first wall protrusion WP<NUM> protrudes and into which the secondary second primary first wall indentation WI<NUM> descends (see <FIG>).

Referring to <FIG>, when the first primary first wall W<NUM> comprises the secondary first primary first wall indentation WI<NUM> and the secondary first primary first wall protrusion WP<NUM>, these are preferably arranged such that a direction of a line LWP12 that runs (i) from a centre of the locking form defined by the first primary first wall indentation WI<NUM> and the first primary first wall protrusion WP<NUM> (ii) to a centre of a locking form defined by the secondary first primary first wall indentation WI<NUM> and the secondary first primary first wall protrusion WP<NUM> is substantially parallel to the tread <NUM>. In other words, the locking forms are preferably not arranged on top of each other in the radial direction SR. The line LWP12 may be parallel to the tread <NUM>. In an embodiment, a minimum angle formed by the line LWP12 with respect to the tread <NUM> is at most <NUM> degrees.

This applies, mutatis mutandis, to the lamella plate <NUM>, too, as discussed above.

In an embodiment, the first tread block TB<NUM> is provided with a secondary first sipe S<NUM>. The secondary first sipe S<NUM> is limited by walls W<NUM> and W<NUM> of the first tread block. The wall W<NUM> may be provided with a wall protrusion WP<NUM> and a wall indentation WI<NUM>. The wall W<NUM> may be provided with a wall protrusion WP<NUM> and a wall indentation WI<NUM>. The walls W<NUM> and W<NUM>, the wall protrusions WP<NUM> and WP<NUM> and the wall indentations WI<NUM> and WI<NUM> may have been formed by a lamella plate as disclosed above.

Thus, in between the primary first sipe S<NUM> and secondary first sipe S<NUM>, a narrow piece of rubber material, i.e. a lamella LAM (see <FIG>), is arranged. A thickness of the lamella LAM may be e.g. <NUM> to <NUM>. Because both the sipes S<NUM> and S<NUM> have been provided with the locking shape as discussed above, also the lamella locks to other parts of the first tread block TB<NUM> on both sides of the lamella. This also improves grip, stability, and handling. Such sipes are shown in <FIG> and <FIG>.

In an embodiment, the tire comprises a second tread block TB2 is provided with a primary second S<NUM> and a secondary second sipe S<NUM> (see <FIG>). Both the primary second S<NUM> and a secondary second sipe S<NUM> may have been made by a lamella plate <NUM> as discussed above. Thus, the primary second sipe S<NUM> is limited by walls W<NUM> and W<NUM> of the second tread block TB<NUM>. The wall W<NUM> may be provided with a wall protrusion WP<NUM> and a wall indentation WI<NUM>. The wall W<NUM> may be provided with a wall protrusion WP<NUM> and a wall indentation WI<NUM>. Moreover, the secondary second sipe S<NUM> is limited by walls W<NUM> and W<NUM> of the second tread block TB<NUM>. The wall W<NUM> may be provided with a wall protrusion WP<NUM> and a wall indentation WI<NUM>. The wall W<NUM> may be provided with a wall protrusion WP<NUM> and a wall indentation WI<NUM>. What has been said about the wall protrusion and indentation in connection with the primary first sipe S<NUM> applies.

Thus, in between the primary second sipe S<NUM> and secondary second sipe S<NUM>, a narrow piece of rubber material, i.e. a lamella, is arranged. A thickness of the lamella may be within the same range as disclosed for the lamella LAM. Because both the sipes S<NUM> and S<NUM> have been provided with the locking shape as discussed above, also the lamella locks to other parts of the second tread block TB<NUM> on both sides of the lamella. This also improves grip and handling. Such sipes are shown in <FIG>.

The sipes discussed above may be used in winter tires or in summer tires. A hardness of a tread material of a summer tire is typically in the range <NUM> to <NUM> Sh(A), i.e. hardness of measured by the Shore scale, durometer type A at the temperature <NUM>.

However, sipes are preferably used in wither tires for the reason discussed above. However, in winter tires, preferably also the tread material per se is reasonably soft. A hardness of a tread material of a winter tire is typically in the range <NUM> to <NUM> Sh(A).

Therefore, in an embodiment, the tread blocks (TB<NUM>, TB<NUM>, TB<NUM>, TB<NUM>) of the tread block arrangement <NUM> are made of rubber having the hardness <NUM> to <NUM> Sh(A). Preferably, the tread blocks (TB<NUM>, TB<NUM>, TB<NUM>, TB<NUM>) of the tread block arrangement <NUM> are made of rubber having the hardness <NUM> to <NUM> Sh(A).

A tire <NUM> having the tread block arrangement <NUM> as described above, may comprise a first marking <NUM> (see <FIG>) indicative of the tire <NUM> being suitable for use as a winter tire. A groove pattern of a winter tire is typically such that a direction of rotation of the tire <NUM> is defined for driving forward. Therefore, in an embodiment, the tire <NUM> comprises a second marking <NUM> indicative of a direction of rotation of the tire when driving forward.

A groove pattern refers to a pattern formed by grooves of the tire. Like a sipe, a groove is a valley in the tread, however, a width of a groove is typically much larger than that of a sipe. Grooves define the tread blocks by separating tread blocks from each other. A groove has a depth and a width. Typically, a depth of a groove is at least <NUM>, such as at least <NUM>, such as from <NUM> to <NUM>. However, the depth needs not be constant. Moreover, near sidewalls of a tire, a depth of a groove may be very small. In fact, the depth may decrease to zero towards the sidewall, depending on the shape of the shoulder area of the tire. Typically, a width of a groove is more than <NUM>, such as more than <NUM>. However, at or near a central area of the tread, a width of a groove may be less. In a central area of the tread, a width of a groove may be e.g. <NUM> or more.

Referring to <FIG>, to further improve grip, the tread <NUM> may be provided with studs <NUM>. Such studs <NUM> improve friction on icy roads. However, the tread <NUM> formed by the tread block arrangement <NUM> is also applicable as a tread of a studless tire. A studless tire may be a summer tire or a winter tire. The tread block arrangement <NUM> may limit an indicator <NUM> indicative of depth of the groove <NUM> (i.e. a wear indicator of the tire <NUM>). The indicator <NUM> may also be indicative of the of the groove <NUM> having a depth that is sufficient or insufficient for driving on a snowy road.

Claim 1:
A tire (<NUM>) comprising
- a tread (<NUM>) provided with a first tread block (TB<NUM>) separated from another tread block (TB<NUM>, TB<NUM>, TB<NUM>) by a portion of a groove (<NUM>), wherein
- the first tread block (TB<NUM>) comprises
• a first primary first wall (W<NUM>) and
• a second primary first wall (W<NUM>) such that a primary first sipe (S<NUM>) is arranged between the first primary first wall (W<NUM>) and the second primary first wall (W<NUM>), wherein
- the first primary first wall (W<NUM>) is provided with a first primary first wall indentation (WI<NUM>) and first primary first wall protrusion (WP<NUM>),
- the second primary first wall (W<NUM>) is provided with a second primary first wall indentation (WI<NUM>) and second primary first wall protrusion (WP<NUM>),
- first primary first wall (W<NUM>) defines a first primary first wall surface (WS<NUM>) having the shape of a planar surface or a curved surface, from which the first primary first wall protrusion (WP<NUM>) protrudes and into which the first primary first wall indentation (WI<NUM>) descends,
- the second primary first wall (W<NUM>) defines a second primary first wall surface (WS<NUM>) having the shape of a planar surface or a curved surface, from which the second primary first wall protrusion (WP<NUM>) protrudes and into which the second primary first wall indentation (WI<NUM>) descends,
- the first primary first wall indentation (WI<NUM>) is geometrically congruent with the second primary first wall protrusion (WP<NUM>), and
- the first primary first wall protrusion (WP<NUM>) is geometrically congruent with the second primary first wall indentation (WI<NUM>),
characterized in that
- the first primary first wall protrusion (WP<NUM>) is antisymmetric about all such planes (WAS) that have a normal that is parallel to a wall projection line (PRW), which is a projection of a line that remains in between a centre of the first primary first wall protrusion (WP<NUM>) and a centre of the first primary first wall indentation (WI<NUM>), the projection being a normal projection to the first primary first wall surface (WS<NUM>).