Knit anti-slip device for pneumatic tire and process for manufacturing such device

Abstract

Anti-skid device (1) and related production process for a wheel of a vehicle wherein the anti-skid device (2) comprises: a belt (2) having a closed circumferential line of development (100), the belt (2) being shaped to fit on a tyre (99) of the wheel for enclosing and covering at least one tread of the tyre (99); a fastening system (9) associated with the belt (2) for fixing the belt to the wheel wherein the belt (2) is made of a warp knitting fabric (3) having a main knitting direction (101) arranged substantially parallel to the circumferential development line (100).

Description

TECHNICAL FIELD

[0001] The present invention relates to an anti-slip device for vehicle wheels and a related production process. BACKGROUND ART

[0002] Known anti-slip devices for vehicle wheels include a woven belt assembled on the tire of the wheel.

[0003] Such anti-slip devices are typically used, for example, as an alternative to chains to facilitate the grip of the wheel on the rolling surface in specific road surface conditions, such as in the case of snow and / or ice, as well as in the case of mud, gravel, and sand.

[0004] The document EP1888353B2 in the name of the same applicant describes an anti-slip device for vehicle wheels, which includes a belt made of a woven material, the belt having a plurality of rib portions arranged in relief, and when the device is assembled on the tire, these rib portions are substantially perpendicular to the rolling direction of the tire. SUMMARY OF THE INVENTION

[0005] "Substantially orthogonal" with respect to geometric elements (such as straight lines, lines, planes, surfaces, etc.) means that these elements (or their tangents) form an angle within the range of 90° ± 15°, preferably 90° ± 10°, including the extreme values.

[0006] "Substantially parallel" with respect to the said geometric elements means that the angle formed by the said elements (or their tangents) is within the range of 0° ± 15°, preferably 0° ± 10°, including the extreme values.

[0007] The terms "radial" and "axial" respectively refer to directions that are (substantially) perpendicular and (substantially) parallel to the central axis of the closed circumferential development line of the belt, and in use, this central axis substantially coincides with the rotation axis of the tire on which the device is assembled.

[0008] The applicant has found that it is advantageous to produce the anti-slip device by a warp knitting process compared to a weft knitting process (in the weft knitting process, for example, the fabric is made of a single yarn, and the yarn is substantially perpendicular to the fabric growth direction in the fabric), and in the warp knitting process, for example, a plurality of individual yarns are fed into the knitting area, the yarns are substantially parallel to each other, and the paths of the individual yarns in the fabric are on average substantially parallel to the main knitting direction.

[0009] The "main knitting direction" refers to the growth direction of the warp knitted fabric during warp knitting (i.e., the direction in which the warp yarns of the fabric grow and develop simultaneously). Generally, the fabric is wound up parallel to the main knitting direction during the production process. When the fabric forms a non-flat shape (such as the tubular shape of the anti-slip device), the main knitting direction is a curve (such as a circumference).

[0010] The applicant has also realized that the production process of the anti-slip device can be improved in certain aspects.

[0011] For example, the applicant has observed that in the anti-slip device described in EP1888353B2, the raised ribs made of the fabric itself are arranged according to (i.e., substantially parallel to) the main knitting direction after the warp knitting process (more generally, the knitting warp). This means that in order to achieve a device in which raised ribs (or more generally, the device for knitting the warp) are arranged such that when the device is assembled on a tire, the raised ribs are substantially perpendicular to the rolling direction of the tire, it is necessary to cut the fabric roll in the height direction of the roll, i.e., perpendicular to the main knitting direction, to obtain the maximum size of the fabric strip.

[0012] In addition, the applicant has also found that further restrictions related to the process (technology) and / or the product must be observed, such as the need to produce fabric strips of different lengths to cover the entire size range of the tire (with different circumferential developments) in a cycle, to limit the waste of the fabric and / or to limit the maximum height of the roll according to the maximum size manageable by various machines used in the production of the strip, such as the thermal stabilization furnace of the fabric and the cutting machine of the fabric roll.

[0013] Therefore, in order to optimize the process conditions according to all the above constraints, a plurality of fabric rolls of different heights have been produced.

[0014] Furthermore, if the length of the strip exceeds the maximum height allowed by the roll, it is necessary to join two (or more) pieces of fabric obtained from different rolls, each roll having a height equal to the length of the strip.

[0015] However, the use of fabric rolls of different heights first brings complexity to the warehouse management, such as in the storage and / or handling of the rolls, and for the rolls with lower heights, the utilization efficiency of the fabric knitting machine (such as the entire available front part where the machine is not used) and the fixed furnace is lower, but the working hours and / or consumption are the same.

[0016] Nevertheless, joining pieces of different lengths to form a fabric strip also involves at least one additional seam along the strip with respect to the seam that tends to close the strip itself (to achieve the circumferential development of the anti-slip device), thus making the subsequent processing more complex.

[0017] Therefore, the applicant has solved the problem of manufacturing an anti-slip device for vehicle wheels in an industrially efficient and / or simple and / or economical way, while maintaining the required anti-slip quality imparted to the tire and / or the structural strength of the anti-slip device itself.

[0018] According to the applicant, the above problem is solved by the anti-slip device and the related production process according to the appended claims and / or having one or more of the following features.

[0019] According to one aspect, the present invention relates to an anti-slip device for a wheel of a vehicle. The anti-slip device comprises:

[0020] - a belt having a closed circumferential development line, the belt being shaped to be adapted to be fitted on a tyre of a wheel for enclosing and covering at least the tread of the tyre;

[0021] - a fastening system associated with the belt, the fastening system being configured to fix the belt to the wheel;

[0022] wherein the belt is made of a warp knitted fabric having a main knitting direction,

[0023] and wherein the main knitting direction is arranged substantially parallel to the circumferential development line (circumferential forming line) of the belt.

[0024] According to another aspect, the present invention relates to a process for producing an anti-slip device for a wheel of a vehicle. The process comprises:

[0025] - warp knitting a warp knitted fabric having a main knitting direction;

[0026] - cutting out a belt from the warp knitted fabric, the belt having a main development direction substantially parallel to the main knitting direction;

[0027] - joining opposite ends of the belt relative to the main development direction of the belt to achieve a closed circumferential development line of the belt, the belt being shaped to be fitted onto a tyre of a wheel for enclosing and covering at least one tread of the tyre;

[0028] - associating the belt with a fastening system configured to fix the belt to the wheel.

[0029] In fact, the applicant has surprisingly found that by arranging the main knitting direction of the fabric substantially parallel to the rolling direction of the tyre (as opposed to the orthogonal arrangement in the prior art), the anti-slip device imparts the required anti-slip performance to the tyre while allowing the production process to be modified such that, in the cutting step, a fabric strip can be cut from a fabric roll such that the maximum dimension of the strip is arranged (substantially) parallel to the main knitting direction, i.e. (substantially) perpendicular to the height of the roll, thereby reducing or even eliminating the above-mentioned problems.

[0030] In fact, in this way, the height of the fabric roll is no longer a limitation on the longitudinal length of the belt, and thus, regardless of the required longitudinal length, the belt can be extended in one piece parallel to the knitting direction, thereby avoiding further stops in the sewing of different pieces.

[0031] Furthermore, by arranging the width (instead of the length) of the belt according to the height of the roll, the number of types of fabric rolls provided in the warehouse can be limited (divided by height), and even the possibility of only producing and storing rolls with the same height can be achieved, which simplifies warehouse management while increasing the utilization and / or cutting benefits (such as limiting waste) of the machines used (e.g., weaving machines and / or fixing furnaces).

[0032] For example, in fact, when the tire size changes, the change in the tread width relative to the corresponding circumferential length changes to a lesser extent, so a smaller number of belt width categories (i.e., groups) are usually sufficient to cover all different tire sizes. Therefore, the height of the roll must take into account the smaller variation range of the belt width. In addition, for a given fabric roll height, the small size of the belt width relative to the longitudinal length enables more width combinations to be achieved, thus optimizing the placement of different belts within the roll surface extension and limiting fabric waste.

[0033] The present invention may have one or more of the following preferred features in one or two of the above aspects.

[0034] Preferably, the warp knitted fabric includes a plurality of first knitted fabric strands and a plurality of second knitted fabric strands woven together.

[0035] Preferably, each first knitted fabric strand and / or second knitted fabric strand is a continuous strand of synthetic material, and the synthetic material is more preferably polypropylene (PP) or polyethylene terephthalate (PET). In this way, for example, compared with the use of natural fibers that degrade over time, the service life of the equipment is increased.

[0036] Preferably, each first knitted fabric strand and / or second knitted fabric strand is a multi-filament knitted fabric strand, more preferably including (at least) 100 filaments, and even more preferably (at least) 120 filaments (and not exceeding 120 filaments). In this way, they are provided with the required robustness.

[0037] Preferably, the fineness (i.e., the ratio of length to weight) of each first knitted fabric strand is greater than or equal to 700 denier, more preferably greater than or equal to 800 denier, and / or less than or equal to 1300 denier, and most preferably less than or equal to 1200 denier.

[0038] Preferably, the fineness of each second knitted fabric strand is greater than or equal to 1200 denier, more preferably greater than or equal to 1300 denier, and / or less than or equal to 1800 denier, and most preferably less than or equal to 1700 denier.

[0039] Preferably, the breaking strength of each first textile thread is greater than or equal to 2 grams per denier, more preferably greater than or equal to 3 grams per denier, and / or less than or equal to 6 grams per denier, more preferably less than or equal to 5 grams per denier.

[0040] Preferably, the breaking strength of each second fabric strand is greater than or equal to 3 grams per denier, more preferably greater than or equal to 4 grams per denier, and / or less than or equal to 7 grams per denier, more preferably less than or equal to 6 grams per denier.

[0041] The applicant has found that the above characteristics of the first fabric strand and the second fabric strand enable a fabric material with desired properties to be obtained, such as in terms of light weight, robustness, wear resistance, etc.

[0042] In a particularly preferred embodiment, the warp knitted fabric (and / or the other fabric and / or the single fabric, further described below) is woven in a "tricot (warp knitting)" manner, more preferably non - run - off, preferably in a "raschel" type weaving, preferably non - run - off, made by means of a raschel type straight weaving mechanism, which weaving machine has a loom that includes (at least) two binding rods, more preferably each binding rod includes a reed hook, and the fineness of the reed hook is equal to (at least) six needles per inch. This way of realizing the fabric has proven to be particularly advantageous, for example, in terms of process efficiency and / or the properties of the fabric obtained for anti - slip purposes.

[0043] Preferably, the warp knitted fabric is heat - stable. Preferably, the process includes heat - stabilizing the warp knitted fabric (for example, by means of a stenter), more preferably before cutting the tape from the fabric. In this way, the dimensional stability of the fabric is improved, making it easier to cut into the appropriate size.

[0044] Preferably, the warp knitted fabric includes a plurality of raised ribs, and the raised ribs are arranged (substantially) parallel to the main weaving direction.

[0045] Preferably, the plurality of ribs are made (directly) by means of the warp knitted fabric, more preferably, one or more first fabric strands are woven with one or more second fabric strands.

[0046] Generally, the ribs are only present on the first side of the warp knitted fabric. Preferably, the second side of the warp knitted fabric opposite to the first side is substantially flat. Preferably, the first side is arranged radially inwards (i.e., facing the tire when the assembly device is used). In other words, contrary to the prior art, in use, the ribs preferably do not contact the rolling surface. In fact, the applicant has surprisingly found that the substantially flat second side effectively performs the anti - slip function.

[0047] Preferably, the thickness of the belt (preferably in the area without ribs) is greater than or equal to 0.2 mm, more preferably greater than or equal to 0.25 mm and / or less than or equal to 0.4 mm, even more preferably less than or equal to 0.35 mm. In this way, the belt is very light while being sufficiently strong.

[0048] Preferably, the fastening system is arranged at (at least) one (more preferably, two) axial end edges of the belt. Preferably, the fastening system comprises (at least) an elastic element having a circumferential development (more preferably, a pair of elastic elements arranged on axially opposite parts of the belt).

[0049] Preferably, the fastening system comprises (at least) one flexible strip (more preferably, a pair of flexible strips for each system), which has a corresponding closed circumferential development line. Preferably, the (each) flexible strip is joined to the belt at the (corresponding) axial end edge of the belt. Preferably, the elastic element is fixed to the flexible strip at the free edge of the flexible strip. This facilitates the fixing of the device to the wheel, for example by causing the flexible strip to contract under elastic action against the tyre.

[0050] Preferably, the (each) flexible strip is made of another woven fabric.

[0051] Preferably, the other fabric has a visual appearance different from that of the fabric. In this way, even if there is a seamless fabric between the belt and the (one or more) strips and there is no circumferential seam (as described below), it is convenient for the correct positioning of the anti-slip device on the tyre because, due to the different visual appearances of the belt and the strips, i.e. they are distinguishable from each other, the user can easily identify the dividing line between the belt and the (each) strip and can verify the correct positioning of the belt and / or the strips relative to the tread and / or the sidewall of the tyre.

[0052] In one embodiment, the other fabric has a color different from that of the fabric. For example, the other fabric comprises one or more woven strands, the color of which is different from the corresponding color of each woven strand of the fabric. In this way, the above-mentioned difference in visual appearance between the belt and the (one or more) strips is achieved in a simple and effective manner.

[0053] In one embodiment, as an alternative or in combination with the previous embodiment, the other fabric has a structure different from that of the fabric. For example, the other fabric has a wider mesh structure than the fabric, such as a large-mesh network structure provided with through openings, and / or includes one or more woven strands, and these woven strands have a fineness different from that of the corresponding woven strands in the fabric, more preferably a higher fineness (for example, the fabric of the belt and the other fabric of the strip also have the same weaving type, that is, the same weaving process). In this way, the above-mentioned difference in visual appearance between the belt and the strip(s) is achieved in a simple and effective manner. In addition, the large-mesh network structure and / or the lightweight network structure make the strip-shaped other fabric lighter and / or softer than the belt-shaped fabric, thus facilitating the curling of the strip under the action of elasticity and being conducive to resistance.

[0054] Preferably, the other fabric has another main weaving direction (substantially) parallel to the main weaving direction. Preferably, the other warp knitted fabric of the (each) flexible strip and the warp knitted fabric of the belt form a single piece (for example, there is no circumferential seam between the belt and the strip). Preferably, the process includes warp knitting the other warp knitted fabric and the warp knitted fabric into a single piece, more preferably, by weaving together a single warp knitted fabric including a part made of the warp knitted fabric and a part made of the other warp knitted fabric, and these two parts alternate with each other along a direction orthogonal to the main weaving direction. Preferably, the cutting of the belt includes cutting out two strips in the other fabric from the single fabric, and the two strips are arranged on opposite parts of the belt, for example, by performing corresponding cuts substantially parallel to the main weaving direction along two parts of the other fabric. The arrangement of the main weaving direction along the circumferential development part of the belt also allows different processed parts to be realized with the same structurally integrated and continuous warp knitted fabric, and / or includes woven strands of different colors and / or finenesses for different functions (for example, functions for the belt and the strip(s) respectively), without interrupting the weaving process (avoiding fixing the other fabric to the woven fabric, such as by sewing). In this way, the process is universal while remaining simple, fast, and / or inexpensive.

[0055] Preferably, the mesh structure of the other fabric includes rectangular through openings, more preferably square through openings. In this way, it is easily achieved, especially by warp knitting.

[0056] Preferably, the main development dimension (main forming dimension) of one or more (more preferably, each) of the through openings (for example, the long side of a rectangle or the side of a square) is greater than or equal to 2 mm, more preferably greater than or equal to 4 mm, and / or less than or equal to 7 mm, more preferably less than or equal to 5 mm. This balances the firmness and vacuum degree of the mesh structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematically shows an anti-slip device according to the present invention mounted on the tire of a wheel;

[0058] Figure 2 Schematically shows Figure 1 details of the device;

[0059] Figure 3 Shows a photograph of details of a warp knitted fabric that can be used for an anti-slip device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0060] With reference to the accompanying drawings, the features and advantages of the present invention will be further clarified by the following detailed description of some embodiments, which are presented by way of example and not limitation of the present invention.

[0061] An anti-slip device for a wheel (not shown) of a vehicle is denoted in the figures by the reference numeral 1.

[0062] The anti-slip device 1 includes a belt 2, the belt 2 having a closed circumferential development line 100 which is shaped to be adapted to be mounted on the tire 99 of a wheel for at least enclosing and covering the tread of the tire. Exemplarily, the belt 2 only completely covers the tread of the tire.

[0063] Exemplarily, in use, the circumferential development line 100 of the belt substantially follows the circumference of the tire and thus is substantially parallel to the rolling direction 200 of the tire (represented by the double arrow).

[0064] The belt 2 is made of a warp knitted fabric 3 which has a main knitting direction 101 arranged, exemplarily, parallel to the circumferential development line 100 (i.e., parallel to the rolling direction of the tire 99).

[0065] The present invention contemplates both belts made entirely of warp knitted fabric and belts that include a warp knitted fabric and one or more inserts attached to the fabric (e.g., the extension of the warp knitted fabric does not necessarily continue along the entire circumferential development line).

[0066] Figure 3 Exemplarily shows a photograph of a warp knitted fabric suitable for manufacturing the belt 2 of an anti-slip device according to the present invention. Exemplarily, Figure 3 the shown warp knitted fabric 3 is made of a "tricot (warp knitting)" anti-run-off knitting structure. In operation, this type of fabric can be advantageously manufactured by using a "Raschel" type straight loom which has a loom consisting of two binding bars, each binding bar including a reed hook with a fineness equal to six needles per inch.

[0067] Other examples of warp knitted fabrics are "Milanese" type woven fabrics and "Raschel" type woven fabrics.

[0068] Exemplarily, the warp knitted fabric 3 includes a plurality of first knitted fabric strands 4 and a plurality of second knitted fabric strands 5 knitted together. In Figure 3 the photograph, the first knitted fabric strands 4 are exemplarily shown in a light color, while the second knitted fabric strands 5 are exemplarily shown in a dark color. Exemplarily, the main knitting direction 101 is substantially consistent with the direction in which the second knitted fabric strands 5 develop on average.

[0069] Exemplarily, each first knitted fabric strand and second knitted fabric strand is a continuous strand of a synthetic material (such as polypropylene (PP)), and is a multi-filament knitted fabric strand exemplarily including 120 filaments.

[0070] Exemplarily, the first knitted fabric strands are different from the second knitted fabric strands. Specifically, each first knitted fabric strand 4 exemplarily has a fineness equal to about 1000 denier and a breaking strength of about 4 grams / denier. Exemplarily, the fineness of each second knitted fabric strand 5 is equal to about 1500 denier, and the breaking strength is equal to about 5 grams / denier.

[0071] Exemplarily, in Figure 2 the warp knitted fabric 3 includes a plurality of raised ribs 6 arranged parallel to the main knitting direction 101. Exemplarily, after the warp knitting production process, the plurality of ribs 6 are directly formed by means of the warp knitted fabric 3. More specifically, each rib 6 is exemplarily realized by knitting the second knitted fabric strands 5 of the plurality of first knitted fabric strands 4. Exemplarily, the ribs 6 are only present on the first side 7 of the warp knitted fabric 3 (usually the side corresponding to the "reverse" side of the fabric), as Figure 2 shown.

[0072] Exemplarily, the belt 2 includes a second side 8 opposite to the first side 7 (as shown in the photograph of Figure 3 ). Exemplarily, the second side 8 is substantially flat. In fact, exemplarily, the undulations at the second side 8 of the warp knitted fabric realized by the first knitted fabric strands and / or the second knitted fabric strands and due to the interweaving have ridges, and the heights of all the ridges are substantially the same and are arranged in a substantially uniform manner in space, ensuring that the overall second side is substantially flat (different from the first side 7, in which the ribs protrude above the remaining part of the fabric).

[0073] Exemplarily, the first side 7 is arranged to face radially inward, that is, when the device is assembled, it faces the tire 99. In other words, the ribs 6 do not contact the rolling surface, but contact the tread of the tire.

[0074] Exemplarily, the thickness of the belt 2 (for example, in the area without ribs) is equal to about 0.3 mm. Exemplarily, the height of the ribs 6 is equal to about 0.8 mm compared to the rest of the first side 7.

[0075] The anti-slip device 1 further includes a fastening system 9 associated with the belt 2, and the fastening system 9 is configured to fix the belt to the wheel.

[0076] Exemplarily, the fastening system 9 is arranged at two axial end edges 20 of the belt 2. More specifically, the fastening system 9 exemplarily includes a pair of flexible strips 10 ( Figure 1 only one is visible in the figure), and each flexible strip has its own closed circumferential development line. Exemplarily, each flexible strip 10 is joined to the belt 2 at the corresponding axial end edge 20 of the belt 2.

[0077] Exemplarily, the fastening system 9 includes a pair of elastic elements (not shown) arranged on axially opposite parts of the belt 2, and each elastic element is fixed to the corresponding flexible strip 10 at the free edge 21 of the flexible strip (for example, sewn to the flexible strip or inserted into a recess made along the edge of the flexible strip).

[0078] Exemplarily, each flexible strip 10 is made of another warp knitted fabric, and its respective main knitting direction is parallel to the main knitting direction 101, and has a large-mesh net structure with through openings (not shown).

[0079] Exemplarily, the other warp knitted fabric of each flexible strip is made into one piece with the warp knitted fabric of the belt 2.

[0080] Exemplarily, the large-mesh net structure includes substantially square openings of about 4 mm.

[0081] In one embodiment, the other fabric may have the same type of weaving as the warp knitted fabric 3.

[0082] In one embodiment, the other fabric may be made of fabric strands of a different color and / or fineness from the fabric strands of the fabric 3.

[0083] Exemplarily, the production process of the anti-slip device 1 first includes warp knitting a warp knitted fabric 3 with the main knitting direction 101 (for example, by means of the above-mentioned raschel machine).

[0084] Exemplarily, the process further includes warp knitting the other warp knitted fabric and the warp knitted fabric into one piece (i.e., in the same knitting process). More specifically, in a preferred embodiment, the process includes weaving a single warp knitted fabric, which includes a part made of the above-mentioned warp knitted fabric 3 and a part made of the above-mentioned other warp knitted fabric, and these parts are alternately (for example, interwoven) with each other along a direction orthogonal to the main knitting direction 101.

[0085] Exemplarily, a heat-stabilized (for example, by a stenter) warp knitted fabric or a single fabric is then provided.

[0086] Thus, exemplarily, the strip 2 is set to be cut from the warp knitted fabric, and the main development direction of the strip (not shown) is substantially parallel to the main knitting direction 101. In other words, one or more cuts are made substantially along the main knitting direction (usually two cuts for each anti-slip device).

[0087] The cutting of the strip 2 is exemplarily carried out in such a way that the width of the shape to be cut (e.g., rectangular) includes the entire width of the part made of the warp knitted fabric 3 (which will form the strip 2), and the width of each part in another warp knitted fabric, respectively arranged on one side (e.g., about half) of the part made of the warp knitted fabric (which will produce two lateral flexible strips). The length of the shape (arranged parallel to the main knitting direction) is exemplarily determined to vary with the tire size targeted by the anti-slip device.

[0088] Thus, exemplarily, the opposite ends of the strip are connected (e.g., by stitching) with reference to the main development direction of the strip to achieve a closed circumferential development line of the strip. At the same time, exemplarily, the opposite ends of the part made of another warp knitted fabric are also joined (e.g., by stitching) to achieve the flexible strip 10.

[0089] Finally, exemplarily, each elastic element is provided to be coupled to the corresponding flexible strip to complete the fastening system 9.

Claims

1. An anti-slip device (1) for a wheel of a vehicle, the anti-slip device (2) comprising: - a belt (2) having a closed circumferential development line (100), the belt (2) being shaped to be adapted to be assembled on a tyre (99) of the wheel for enclosing and covering at least the tread of the tyre (99); - a fastening system (9) associated with the belt (2), the fastening system being configured to fix the belt (2) to the wheel; wherein the belt is made of a warp knitted fabric (3) having a main knitting direction (101), and wherein the main knitting direction (101) is arranged substantially parallel to the circumferential development line (100) of the belt (2).

2. The device (1) according to claim 1, characterized in that The warp knitted fabric (3) comprises a plurality of first knitted fabric strands (4) and a plurality of second knitted fabric strands (5) knitted to each other, wherein each first knitted fabric strand (4) and / or second knitted fabric strand (5) is a continuous strand made of a synthetic material, preferably made of polypropylene or polyethylene terephthalate, and wherein each first knitted fabric strand (4) and / or second knitted fabric strand (5) is a multi-filament knitted fabric strand comprising at least 100 filaments.

3. The device (1) according to claim 2, characterized in that, The fineness of each first knitted fabric strand (4) is greater than or equal to 700 denier and less than or equal to 1300 denier, and the breaking strength is greater than or equal to 2 grams / denier and greater than or equal to 6 grams / denier, wherein the fineness of each second knitted fabric strand (5) is greater than or equal to 1200 denier and less than or equal to 1800 denier, and the toughness is greater than or equal to 3 grams / denier and less than or equal to 7 grams / denier, and wherein the warp knitted fabric (3) is thermally stable.

4. The device (1) according to any one of the preceding claims, characterized in that, The warp knitted fabric (3) comprises a plurality of raised ribs (6), the ribs being arranged substantially parallel to the main knitting direction (101), wherein the plurality of ribs (6) are made by means of the warp knitted fabric (3), wherein the ribs (6) are present only on a first face (7) of the warp knitted fabric (3), a second face (8) of the warp knitted fabric (3) opposite to the first face (7) being substantially flat, wherein the first face (7) is arranged radially inwards, and wherein the belt (2) has a thickness greater than or equal to 0.2 mm and less than or equal to 0.4 mm.

5. The device (1) according to any one of the preceding claims, characterized in that, The fastening system (9) is arranged at at least one axial end edge (20) of the belt (2), wherein the fastening system (9) comprises at least one elastic element having a circumferential development.

6. The device (1) according to claim 5, characterized in that, The fastening system (9) comprises at least one flexible strip (10) having a corresponding closed circumferential development line, wherein the flexible strip (10) is joined to the belt at the axial end edge (20) of the belt (2), and wherein the elastic element is fixed to the flexible strip at a free edge (21) of the flexible strip.

7. The device (1) according to claim 6, characterized in that, The flexible strip (10) is made of another warp knitted fabric, wherein the other warp knitted fabric of the flexible strip (10) and the warp knitted fabric (3) of the strip (2) form a single piece, wherein the other warp knitted fabric has a large-mesh network structure, the large-mesh network structure is provided with through openings, and another main knitting direction substantially parallel to the main knitting direction (101), wherein the large-mesh network structure includes rectangular openings, and wherein one or more of the through openings have a main development dimension greater than or equal to 2 mm and less than or equal to 7 mm.

8. The device (1) according to any one of the preceding claims, characterized in that, The warp knitted fabric (3) is made by "Tricot" weaving, preferably anti-run-off weaving, using a Raschel-type straight loom, the Raschel-type linear loom having a loom including at least two tying rods, each tying rod including a reed hook, the fineness of the reed hook being equal to at least six needles per inch.

9. A process for producing an anti-slip device (1) for a vehicle wheel, the process comprising: - warp knitting a warp knitted fabric (3) having a main knitting direction (101); - cutting a strip (2) from the warp knitted fabric (3), the strip having a main development direction substantially parallel to the main knitting direction (101); - joining the opposite ends of the strip relative to the main development direction of the strip (2) to achieve a closed circumferential development line (100) of the strip (2), the strip being shaped to fit onto a tire (99) of the wheel to enclose and cover at least the tread of the tire (99); - associating the strip (2) with a fastening system (9), the fastening system being configured to fix the strip (2) to the wheel.

10. The method according to claim 9, wherein including heat stabilizing the warp knitted fabric (3) before cutting the strip (2) from the warp knitted fabric, wherein the process includes warp knitting another warp knitted fabric and the warp knitted fabric (3) into a single piece.

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