Textile antiskid device for a pneumatic tire and manufacturing process of such a device

Abstract

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

Description

[0001] DESCRIPTION

[0002] TEXTILE ANTISKID DEVICE FOR A PNEUMATIC TIRE AND MANUFACTURING PROCESS OF SUCH A DEVICE

[0003] Technical field of the invention

[0004] The present invention concerns an anti-skid device for wheels of a vehicle and a relative production process.

[0005] Prior art

[0006] Anti-skid devices for vehicle wheels, comprising a textile band to be fitted on the tyre of the wheel, are known.

[0007] Such anti-skid devices are typically used, for example as an alternative to chains, to favour the grip of the wheels to the rolling surface in particular road surface conditions, such as in the case of snow and / or ice, but also in the case of mud, gravel, sand.

[0008] Document EP1888353B2, in the name of the same Applicant, describes an anti-skid device for wheels of a vehicle comprising a band made of textile material having a plurality of ribs in relief arranged, when the device is fitted on the tyre, substantially perpendicular to the rolling direction of the tyre.

[0009] Summary of the invention

[0010] By ‘substantially orthogonal’ relatively to geometric elements (such as straight lines, lines, planes, surfaces etc.) it is meant that these elements (or the tangents thereof) form an angle within the range of 90°+ / -15°, preferably 90°+ / -10°, extremes included.

[0011] By ‘substantially parallel’ relatively to said geometric elements it is meant that said elements (or the tangents thereof) form an angle comprised in the range 0°+ / -15°, preferably 0°+ / -10°, extremes included.

[0012] The terms "radial" and "axial" are used with reference respectively to a direction (substantially) orthogonal to and to a direction (substantially) parallel to a central axis of the closed circumferential line of development of the band, which in use substantially coincides with the axis of rotation of the tyre on which the device is fitted.

[0013] The Applicant has found it advantageous to produce the anti-skid devices by means of a warp knitting process, e.g. where a plurality of individual yarns are fed to the knitting zone with the yarns substantially parallel to each other and where the path of the individual yarns in the knitted fabric is on average substantially parallel to the main knitting direction), compared to a weft knitting process, e.g. where the fabric is made by means of a single yarn and where the yarn develops in the fabric substantially perpendicular to the direction of fabric growth). ‘Main knitting direction’ means the direction of growth of the warp knitted fabric during warp knitting (i.e. the direction along which the warps of the fabric are simultaneously grown and developed). Typically, the fabric is rolled, as it is produced, parallelly to the main knitting direction. The main knitting direction, when the fabric is formed into non-flat shapes (such as the tubular shape of the anti-skid device), is a curved line (e.g. a circumference).

[0014] The Applicant has also realised that the production process of the anti-skid devices can be improved in some aspects.

[0015] For example, the Applicant has observed that in the anti-skid device described in EP1888353B2, the ribs in relief made by means of the fabric itself following the warp knitting process (and more generally the knitting warps) are arranged according to (i.e. - substantially - parallelly to) the main knitting direction. This entails that in order to realize a device in which the ribs in relief (or more generally the knitting warps) are arranged, when the device is fitted on the tyre, substantially perpendicularly to the rolling direction of the tyre, it is necessary to cut the rolls of fabric in such a way that the largest dimension of the textile band is obtained in the direction of the height of the roll, i.e. perpendicularly to the main knitting direction.

[0016] In addition to this, the Applicant has also found that further constraints relating to the process and / or the product must be respected, such as the need to produce textile bands having different lengths in order to cover the entire range of sizes of tyres in circulation (having different circumferential developments), to limit the scrap of fabric and / or to limit the maximum height of the rolls as a function of the maximum dimensions manageable by the various machines used in the realization of the bands, such as for example the thermal stabilisation furnaces of the fabric and the cutting machines of the fabric rolls.

[0017] It therefore follows, in order to optimize the process conditions in compliance with all the aforesaid constraints, the production of a plurality of fabric rolls having different heights between them.

[0018] Furthermore, in the event that a band has a length exceeding the maximum height allowed for the rolls, 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 band piece.

[0019] However, the use of fabric rolls with different heights first of all brings about a complication in the management of the warehouse, for example in terms of storage and / or handling of the rolls, as well as, for rolls with lower heights, a lower yield of use of the fabric knitting machines (in which for example the entire available front of the machine is not used), as well as of the fixing furnaces, with the same working times and / or consumption.

[0020] Still, joining pieces of different length to create a single band of fabric also involves the presence, along the band, of at least one additional seam with respect to that intended to close the band on itself (to realize the circumferential development of the anti-skid device), with consequent greater processing.

[0021] The Applicant has therefore addressed the problem of making an anti-skid device for wheels of a vehicle with an industrially efficient and / or simple and / or economical process, while maintaining the desired anti-skid qualities conferred on the tyre and / or the structural robustness of the anti-skid device itself.

[0022] According to the Applicant, the aforesaid problem is solved by an anti-skid device and a relative production process in accordance with the appended claims and / or having one or more of the following characteristics.

[0023] According to one aspect the invention concerns an anti-skid device for a wheel of a vehicle. The anti-skid device comprises:

[0024] - a band having a closed circumferential line of development, said band being shaped to be fitted on a tyre of said wheel, for enclosing and covering at least a tread of said tyre;

[0025] - a fastening system associated with said band and structured for fixing said band to said wheel; wherein said band is made of warp knitted fabric having a main knitting direction, and wherein said main knitting direction is arranged (substantially) parallelly to said circumferential line of development of said band.

[0026] According to another aspect the invention concerns a process for producing an anti-skid device for a wheel of a vehicle. The process comprises:

[0027] -warp knitting a warp knitted fabric having a main knitting direction;

[0028] - cutting from said warp knitted fabric a band having a main development direction substantially parallel to said main knitting direction;

[0029] - joining mutually opposite ends of said band with reference to said main development direction of the band for realizing a closed circumferential line of development of said band, said band being shaped to be fitted onto a tyre of said wheel and for enclosing and covering at least one tread of said tyre;

[0030] - associating with said band a fastening system structured for fixing said band to said wheel.

[0031] The Applicant has in fact surprisingly found out that by arranging the main knitting direction of the fabric substantially parallelly to the rolling direction of the tyre (contrary to an orthogonal arrangement like in the prior art), the anti-skid device confers on the tyre the desired qualities of resistance to skidding, at the same time allowing to modify the production process in such a way that, in the cutting step, the band of fabric can be cut from the fabric roll so that the largest dimension of the band is arranged (substantially) parallelly to the main knitting direction, that is (substantially) orthogonally to the height of the roll, allowing to reduce, even eliminate, the problems described above.

[0032] In fact, in this way the height of the fabric roll is no longer a limit to the longitudinal length of the band, which can therefore extend in single piece parallelly to the knitting direction regardless of the desired longitudinal length, thus avoiding further stops of sewing of distinct pieces.

[0033] Furthermore, by arranging the width (instead of the length) of the band according to the height of the roll, it is possible to limit the number of types of fabric rolls (divided by height) to be provided in the warehouse, even attaining the possibility of producing and storing only rolls having the same height, simplifying the management of the warehouse and at the same time improving the yield of use of the machines used (e.g. weaving machines and / or fixing furnaces), and / or the cutting yield (e.g. limiting scraps).

[0034] For example, in fact, when the tyre size varies, the tread widths vary to a lesser extent with respect to the variation of the respective circumferential lengths, and therefore a smaller number of classes (i.e. groups) of band widths is generally sufficient to cover all the different tyre sizes. Therefore, the heights of the rolls must be made taking into account a smaller range of variability of the widths of the bands. In addition, the small dimensions of the widths of the bands with respect to the longitudinal lengths make it possible to realize, for a given height of the fabric roll, more combinations of widths, allowing to optimize the placement of the different bands within the surface extension of the roll, limiting the scrap of fabric.

[0035] The present invention in one or both of the above aspects may have one or more of the following preferred features.

[0036] Preferably said warp knitted fabric comprises a plurality of first textile threads and a plurality of second textile threads knitted together.

[0037] Preferably each first and / or second textile thread is a continuous thread in synthetic material, more preferably in polypropylene (PP) or in polyethylene terephthalate (PET). In this way, the useful life of the device is improved, for example compared to the use of natural fibres that can degrade over time.

[0038] Preferably each first and / or second textile thread is a multi-filament textile thread, more preferably comprising (at least) 100 filaments, even more preferably (at least) 120 filaments (and no more than 120 filaments). In this way, they are provided with the desired robustness.

[0039] Preferably each first textile thread has fineness (i.e. length to weight ratio) 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, more preferably less than or equal to 1200 denier.

[0040] Preferably each second textile thread has fineness 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, more preferably less than or equal to 1700 denier.

[0041] Preferably each first textile thread has tenacity greater than or equal to 2 g / denier, more preferably greater than or equal to 3 g / denier, and / or less than or equal to 6 g / denier, more preferably less than or equal to 5 g / denier.

[0042] Preferably each second textile thread has tenacity greater than or equal to 3 g / denier, more preferably greater than or equal to 4 g / denier, and / or less than or equal to 7 g / denier, more preferably less than or equal to 6 g / denier.

[0043] The Applicant has found that the aforesaid characteristics referred to the first and second textile threads make it possible to obtain a textile material having the desired properties, for example in terms of lightness, robustness, wear resistance, etc.

[0044] In a particularly preferred embodiment said warp knitted fabric (and / or said further fabric and / or said single fabric, described further below) is made with a "tricot' -type weave, more preferably run-proof, preferably by means of a "Raschel”-type weave, preferably run-proof, by means of a Raschel-type linear weaving machine having a loom comprising (at least) two tying bars, more preferably each tying bar comprising reed hooks having a fineness equal to (at least) six needles / inch. This type of realization of the fabric has proved to be particularly advantageous, for example in terms of process efficiency and / or properties of the fabric obtained for the purpose of anti-skid.

[0045] Preferably said warp knitted fabric is thermally stabilized. Preferably said process comprises thermally stabilizing (e.g. through stenter) said warp knitted fabric, more preferably prior to said cutting from said fabric said band. In this way, the dimensional stability of the fabric is improved, making it easier to cut to size.

[0046] Preferably said warp knitted fabric comprises a plurality of ribs in relief arranged (substantially) parallel to said main knitting direction.

[0047] Preferably said plurality of ribs is made (directly) by means of said warp knitted fabric, more preferably by means of one or more second textile threads knitting one or more first textile threads.

[0048] Typically the ribs are present only on a first face of the warp knitted fabric. Preferably a second face of the warp knitted fabric, opposite the first face, is substantially flat. Preferably said first face is arranged radially internally (i.e. facing the tyre when the device is fitted). In other words, contrary to the prior art, in use the ribs are preferably not in contact with the rolling surface. In fact, the Applicant has surprisingly found out that the second face, substantially flat, effectively performs the anti-skid function.

[0049] Preferably, said band has a thickness (preferably at a region without ribs) 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, plus preferably less than or equal to 0.35 mm. In this way, the band is light and at the same time sufficiently robust.

[0050] Preferably said fastening system is arranged at (at least) one (more preferably both) axial end edge of said band. Preferably said fastening system comprises (at least) an elastic element having circumferential development (more preferably a pair of elastic elements arranged on axially opposite parts of the band).

[0051] Preferably said fastening system comprises (at least) one flexible strip (more preferably a pair of flexible strips each) having a respective closed circumferential line of development. Preferably said (each) flexible strip is coupled to said band at an (respective) axial end edge of the band. Preferably said elastic element is fixed to said flexible strip, at a free edge of the flexible strip. This facilitates the fixing of the device to the wheel, for example by contraction of the flexible strip against the tyre under the action of the elastic.

[0052] Preferably said (each) flexible strip is made of a further warp knitted fabric.

[0053] Preferably said further fabric has a visual appearance different from a visual appearance of said fabric. In this way, even with a single seamless fabric between band and strip(s) and without circumferential seams (as described below), the correct positioning of the anti-skid device on the tyre is facilitated, as the user easily recognizes, thanks to the different visual appearance between band and strip, i.e. distinguishable from one another, the line of separation between band and (each) strip and can verify the correct positioning of the band and / or strip with respect to the tread and / or sidewalls of the tyre.

[0054] In one embodiment, said further fabric has a colour different from a colour of said fabric, for example said further fabric comprises one or more textile threads having a colour different from a respective colour of each textile thread of said fabric. In this way, the aforesaid difference in visual appearance between the band and the strip(s) is realized in a simple and effective way.

[0055] In an embodiment, alternative to, or in combination with, the immediately preceding embodiment, said further fabric has a structure different from a structure of said fabric, for example said further fabric has a wider-mesh net structure than said fabric, e.g. a large-mesh net structure provided with through openings, and / or comprises one or more textile threads having a different fineness from, more preferably higher than, corresponding textile threads in said fabric (e.g. also with a same type of weave of the fabric of the band and of the further fabric of the strip, i.e. a same knitting process). In this way, the aforesaid difference in visual appearance between the band and the strip(s) is realized in a simple and effective way. In addition, the large- and / or lightweight-mesh net structure makes the additional fabric of the strip lighter and / or more flexible than the fabric of the band, thus facilitating the curling of the strip under the action of the elastic, to the benefit of the resistance.

[0056] Preferably said further fabric has a further main knitting direction (substantially) parallel to said main knitting direction. Preferably said further warp knitted fabric of said (each) flexible strip is in single piece with said warp knitted fabric of said band (e.g. free of circumferential seams between band and strip). Preferably said process comprises warp knitting a further warp knitted fabric in single piece with said warp knitted fabric, more preferably by weaving together a single warp knitted fabric comprising portions made of said warp knitted fabric and portions made of said further warp knitted fabric alternating with each other along a direction orthogonal to said main knitting direction. Preferably said cutting said band comprises cutting from said single fabric also two strips in said further fabric arranged on opposite parts of said band, e.g. by making a respective cut substantially parallel to said main knitting direction along two portions in said further fabric. The arrangement of the main knitting direction along the circumferential development of the band also allows to realize, in a same structurally cohesive and continuous warp knitted fabric, portions with differentiated processing, and / or comprising textile threads of different colour and / or fineness, used for different functions (e.g. respectively the functions of the band and the strip(s)), without interruptions of the knitting process (avoiding the fixing operations, e.g. by sewing, of the additional fabric to the knitted fabric). In this way the process is versatile while remaining simple, and / or quick and / or inexpensive.

[0057] Preferably said mesh net structure of the further fabric comprises rectangular, more preferably square, through openings. In this way it is simple to realize, in particular by warp knitting.

[0058] Preferably one or more (more preferably each) of said through openings has a major development dimension (e.g. larger side of the rectangle, or side of the square) 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 robustness and degree of vacuum of the mesh net structure.

[0059] Brief description of the figures

[0060] Figure 1 schematically shows an anti-skid device according to the present invention fitted on a tyre of a wheel; figure 2 schematically shows a detail of the device of figure 1 ; figure 3 shows a photograph of a detail of a warp knitted fabric usable in the anti-skid device according to the present invention.

[0061] Detailed description of preferred embodiments of the invention

[0062] The features and advantages of the present invention will be further clarified by the following detailed description of some embodiments, presented by way of example and not by way of limitation of the present invention, with reference to the appended figures. An anti-skid device for a wheel of a vehicle (not shown) is indicated in the figures with the number 1 .

[0063] The anti-skid device 1 comprises a band 2, having a closed circumferential line of development 100, shaped to be fitted on a tyre 99 of the wheel, for enclosing and covering at least the tread of the tyre. Exemplarily, the band 2 entirely covers only the tread of the tyre.

[0064] Exemplarily, in use, the circumferential line of development 100 of the band lies substantially along a circumferential development of the tyre, thus being substantially parallel to the rolling direction 200 (represented by a double arrow) of the tyre.

[0065] The band 2 is made of warp knitted fabric 3 having a main knitting direction 101 exemplarily arranged parallelly to the circumferential line of development 100 (i.e. parallelly to the rolling direction of the tyre 99).

[0066] The present invention contemplates both bands made entirely of warp knitted fabric, and bands comprising warp knitted fabric and one or more inserts coupled to the fabric (e.g. with extension of the warp knitted fabric not necessarily continuous along the entire circumferential line of development).

[0067] Figure 3 exemplarily shows the photograph of a warp knitted fabric adapted to make the band 2 of the anti-skid device according to the present invention. Exemplarily, the warp knitted fabric 3 shown in figure 3 is made with a "tricot' -type run-proof weave. Operationally, this type of fabric can be advantageously made by using a "Raschel”-type linear weaving machine having a loom comprising two tying bars, each tying bar comprising reed hooks having a fineness equal to six needles / inch

[0068] Other examples of warp knitted fabric are the "Milanese"-type woven fabric and the "Raschel"-type woven fabric.

[0069] Exemplarily, the warp knitted fabric 3 comprises a plurality of first textile threads 4 and a plurality of second textile threads 5 knitted together. In the photograph of figure 3, the first textile threads 4 are exemplarily shown in light colour, while the second textile threads 5 are exemplarily shown in dark colour. Exemplarily, the main knitting direction 101 substantially coincides with the direction along which the second textile threads 5 develop on average.

[0070] Exemplarily each first and second textile thread is a continuous thread of synthetic material, for example polypropylene (PP), and is a multi-filament textile thread exemplarily comprising 120 filaments.

[0071] Exemplarily, the first textile threads are different from the second textile threads. In detail, each first textile thread 4 exemplarily has fineness equal to about 1000 denier and a tenacity equal to about 4 g / denier. Exemplarily, each second textile thread 5 has fineness equal to about 1500 denier and a tenacity equal to about 5 g / denier.

[0072] Exemplarily, in figure 2, the warp knitted fabric 3 comprises a plurality of ribs 6 in relief, arranged parallel to the main knitting direction 101. Exemplarily the plurality of ribs 6 is made directly by means of the warp knitted fabric 3 following the production process by warp knitting, more in detail each rib 6 being exemplarily realized by means of a second textile thread 5 knitting a plurality of first textile threads 4. Exemplarily, the ribs 6 are present only on a first face 7 of the warp knitted fabric 3 (typically the face corresponding to the "reverse" side of the fabric), shown schematically and partially in Figure 2.

[0073] Exemplarily the band 2 comprises a second face 8 (shown in the photograph of figure 3), opposite to the first face 7. Exemplarily, the second face 8 is substantially flat. Exemplarily, in fact, the corrugations present at the second face 8, realized by the first and / or second textile threads and due to the mutual intertwining to realize the warp knitted fabric, have ridges all having substantially the same height and arranged in a spatially substantially homogeneous manner, ensuring that the second face 8 is substantially planar overall (unlike the first face 7 where the ribs rise above the remaining portion of fabric below). Exemplarily, the first face 7 is arranged radially internally, i.e. it faces the tyre 99 when the device is fitted. In other words, the ribs 6 are not in contact with the rolling surface but are in contact with the tread of the tyre.

[0074] Exemplarily, the band 2 has a thickness (e.g. at a region without ribs) equal to about 0.3 mm. Exemplarily, the ribs 6 have a height, compared to a remaining portion of the first face 7, equal to about 0.8 mm.

[0075] The anti-skid device 1 further comprises a fastening system 9 associated with the band 2 and structured for fixing the band to the wheel.

[0076] Exemplarily, the fastening system 9 is arranged at both axial end edges 20 of the band 2. In more detail, the fastening system 9 exemplarily comprises a pair of flexible strips 10 (only one visible in Figure 1 ), each having a respective closed circumferential line of development. Exemplarily each flexible strip 10 is coupled to the band 2 at a respective axial end edge 20 of the band 2.

[0077] Exemplarily, the fastening system 9 comprises a pair of elastic elements (not shown) arranged on axially opposite parts of the band 2, each elastic element being fixed to a respective flexible strip 10, at a free edge 21 of the flexible strip (e.g. sewn to the flexible strip or inserted into a pocket made along the edge of the flexible strip).

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

[0079] Exemplarily the further warp knitted fabric of each flexible strip is in single piece with the warp knitted fabric of band 2.

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

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

[0082] In one embodiment, the further fabric may be made of textile threads of a different colour and / or fineness than the textile threads of the fabric 3.

[0083] Exemplarily, the production process of the anti-skid device 1 comprises first of all warp knitting (e.g. by means of the aforesaid Raschel machine) the warp knitted fabric 3 having the main knitting direction 101.

[0084] Exemplarily the process further comprises warp knitting the further warp knitted fabric in single piece with the warp knitted fabric (i.e. in the same knitting process). More in detail, in a preferred embodiment, the process comprises weaving a single warp knitted fabric comprising portions made of the aforesaid warp knitted fabric 3 and portions made of the aforesaid further warp knitted fabric alternating with each other (e.g. interleaved) along a direction orthogonal to the main knitting direction 101.

[0085] Exemplarily, it is subsequently provided to thermally stabilize (e.g. through stenter) the warp knitted fabric or the single fabric.

[0086] Exemplarily, it is therefore provided to cut the band 2 from the warp knitted fabric with a main development direction (not shown) of the band substantially parallel to the main knitting direction 101. In other words, one or more cuts (typically two cuts for each antiskid device) are made substantially along the main knitting direction.

[0087] The cut of the band 2 is exemplarily made in such a way as to comprise in the width of the shape (e.g. rectangular) to be cut an entire width of a portion made of warp knitted fabric 3 (which will make the band 2) and a fraction of the (e.g. about half) width of each portion in further warp knitted fabric respectively (which will make the two lateral flexible strips) arranged on the side of the portion made of warp knitted fabric. The length of the shape (arranged parallelly to the main knitting direction) is exemplarily established as a function of the size of the tyre for which the anti-skid device is intended.

[0088] Exemplarily, it is therefore provided to join (e.g. by sewing) mutually opposite ends of the band with reference to the main development direction of the band to realize a closed circumferential line of development of the band. At the same time, it is exemplary provided to join (e.g. by sewing) also opposite ends of the portions made of further warp knitted fabric to realize the flexible strips 10.

[0089] Finally, it is exemplarily provided to couple each elastic element to the respective flexible strip to complete the fastening system 9.

Claims

CLAIMS1 . Anti-skid device (1 ) for a wheel of a vehicle, the anti-skid device (1 ) comprising:- a band (2) having a closed circumferential line of development (100), said band (2) being shaped to be fitted on a tyre (99) of said wheel, for enclosing and covering at least a tread of said tyre (99);- a fastening system (9) associated with said band (2) and structured for fixing said band(2) to said wheel; wherein said band is made of warp knitted fabric (3) having a main knitting direction (101 ), and wherein said main knitting direction (101 ) is arranged substantially parallelly to said circumferential line of development (100) of said band (2).

2. Device (1 ) according to claim 1 , wherein said warp knitted fabric (3) comprises a plurality of first textile threads (4) and a plurality of second textile threads (5) knitted to each other, wherein each first (4) and / or second textile thread (5) is a continuous thread made of synthetic material, preferably made of polypropylene or polyethylene terephthalate, and wherein each first (4) and / or second textile thread (5) is a multifilament textile thread, comprising at least 100 filaments.

3. Device (1 ) according to claim 2, wherein each first textile thread (4) has fineness greater than or equal to 700 denier and less than or equal to 1300 denier, and tenacity greater than or equal to 2 g / denier and less than or equal to 6 g / denier, wherein each second textile thread (5) has fineness greater than or equal to 1200 denier and less than or equal to 1800 denier, and tenacity greater than or equal to 3 g / denier and less than or equal to 7 g / denier, and wherein said warp knitted fabric (3) is thermally stabilized.

4. Device (1 ) according to any one of the previous claims, wherein said warp knitted fabric(3) comprises a plurality of ribs (6) in relief arranged substantially parallel to said main knitting direction (101 ), wherein said plurality of ribs (6) is made by means of said warp knitted fabric (3), wherein said ribs (6) are present only on a first face (7) of said warp knitted fabric (3), a second face (8) of the warp knitted fabric (3), opposite the first face (7), being substantially flat, wherein said first face (7) is arranged radially internally, and wherein said band (2) has thickness greater than or equal to 0,2 mm and less than or equal to 0,4 mm.

5. Device (1 ) according to any one of the previous claims, wherein said fastening system (9) is arranged at at least one axial end edge (20) of said band (2), wherein said fastening system (9) comprises at least one elastic element having circumferential development.

6. Device (1 ) according to claim 5, wherein said fastening system (9) comprises at leastone flexible strip (10) having a respective closed circumferential line of development, wherein said flexible strip (10) is coupled to said band (2) at said axial end edge (20) of the band (2), and wherein said elastic element is fixed to said flexible strip (10), at a free edge (21 ) of the flexible strip (10).

7. Device (1 ) according to claim 6, wherein said flexible strip (10) is made of a further warp knitted fabric, wherein said further warp knitted fabric of said flexible strip (10) is in single piece with said warp knitted fabric (3) of said band (2), wherein said further warp knitted fabric has large-mesh net structure provided with through openings and a further main knitting direction substantially parallel to said main knitting direction (101 ), wherein said large-mesh net structure comprises rectangular openings, and wherein one or more of said through openings has a main development dimension greater than or equal to 2 mm and less than or equal to 7 mm.

8. Device (1 ) according to any one of the previous claims, wherein said warp knitted fabric (3) is made with a "tricot' -type weave, preferably run-proof, by means of a Raschel-type linear weaving machine having a loom comprising at least two tying bars, each tying bar comprising reed hooks having a fineness equal to at least six needles / inch.

9. Process for producing an anti-skid device (1 ) for a wheel of a vehicle, the process comprising:- warp knitting a warp knitted fabric (3) having a main knitting direction (101 );- cutting from said warp knitted fabric (3) a band (2) having a main development direction substantially parallel to said main knitting direction (101 );- joining mutually opposite ends of said band (2) with respect to said main development direction of the band (2) for realizing a closed circumferential line of development (100) of said band (2), said band (2) being shaped to be fitted onto a tyre (99) of said wheel for enclosing and covering at least a tread of said tyre (99);- associating with said band (2) a fastening system (9) structured for fixing said band (2) to said wheel.

10. Process according to claim 9, comprising thermally stabilizing said warp knitted fabric (3) previously to said cutting from said warp knitted fabric said band (2), and wherein said process comprises warp knitting a further warp knitted fabric in single piece with said warp knitted fabric (3).

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