Abstract:
Slip-proof cover for vehicle tyres for use in adverse weather conditions, preferably snow or ice, with a configuration that allows a simple mounting. The cover is highly reliable and positionally stable, and has a good mechanical performance with respect to abrasion. The cover has a structure and composition of the cut swath that optimise its slip-proof characteristics and its resistance to abrasion.

Description:
OBJECT OF THE INVENTION  
       [0001]     The present invention relates to a slip-proof cover for vehicle tyres in adverse weather conditions, preferably ice or snow.  
         [0002]     The cover is characterised by a configuration that makes it easy to mount, providing a high reliability and positional stability and good mechanical properties regarding the abrasion implied by its use in its intended conditions.  
         [0003]     The cover is also characterised by a structure and composition of the slit that optimise its slip-proof capacities and its resistance to abrasion.  
       BACKGROUND OF THE INVENTION  
       [0004]     Driving a vehicle provided with inflatable tyres on slippery surfaces such as snow or ice is dangerous, due to the sharp reduction of the coefficient of friction.  
         [0005]     If the coefficient of friction is reduced by the presence of ice, the latter&#39;s stiffness requires the use of solutions based on metal protrusions or the like.  
         [0006]     Tyres are known with studs meant to insert in the ice or snow to improve the grip.  
         [0007]     This type of tyres are used when there are snow or ice conditions at all times, such as for vehicles used in ski resorts.  
         [0008]     In situations where an improved grip is occasionally required, such as when having to cross a snow-covered mountain pass, other auxiliary means are common that are easier to mount and remove, such as snow chains.  
         [0009]     Auxiliary elements of this type use diverse attachment solutions that seek a simple installation.  
         [0010]     Chains are bulky and take up significant space in the vehicle&#39;s luggage compartment. The stiffness of the chain allows it to stick in the snow; however, it also means that considerable stresses are applied on the tyre surface, damaging it.  
         [0011]     This damage is greater when there are areas without snow to cushion the impact of the chain on the ground. These areas are sometimes so short that it is not worth removing and installing the chains again.  
         [0012]     Also known is the use of covers as alternative to chains. In this sense must be cited European Patent with publication number EP1165329, which describes and protects a device that can be fitted on vehicle tyres to increase the friction between the tyre and the road.  
         [0013]     The configuration of this cover consists of a belt that surrounds the tyre with an oversize of 4%, its outer part being fully closed and its inner part having a strip with an elastic peripheral asymmetric tensor.  
         [0014]     The present invention consists of a design of a cover with a fabric specifically conceived to withstand shear stresses, improve the grip and improve positional stability.  
       DESCRIPTION OF THE INVENTION  
       [0015]     The present invention consists of a slip-proof cover for vehicle tyres that consists of a main band made of high-strength textile material and symmetrically-arranged lateral elastic adjusters that facilitate mounting and removing it.  
         [0016]     The high-strength central band consists of a swath of cord fabric made of several strands.  
         [0017]     The presence of several strands allows to increase the strength and thickness of each cord to provide a surface with a better grip on the slippery surface.  
         [0018]     The main textile band includes cords of different thickness, providing the band with protrusions and irregularities that improve its adherence to the ground.  
         [0019]     The fabric incorporates a textile ligament, preferably made of taffeta, which completes the composition of the fabric.  
         [0020]     The main band is a swath cut along an angle from 45° to 90° so that fibres that were originally longitudinal and transverse will be at a 45° angle. Note that angles under 45° result in equivalent configurations, as the longitudinal fibres become transverse fibres.  
         [0021]     The specific case in which the angle is 45° with variations of up to 10° in the orientation of the fibres is of particular interest. This inclination has been compared to the natural orientation of 90° and has been shown to improve the two variables of greatest interest: friction on slippery surfaces such as snow or ice and resistance to wear.  
         [0022]     The reason for this is that the unravelling is minimised, as the forces act identically on all fibres. It must be pointed out that if the longitudinal or transverse fibres suffer greater loads or abrasion than the others the entire fabric is deteriorated. The ideal solution is to balance the external demands on the fibre between the fibres having one orientation and the other, to provide an optimum overall performance.  
         [0023]     Possible cutting means are laser, scissors or heat soldering. In cases in which cutting produces localised fusion, cut ends show a lower tendency to unravelling before they are sewn.  
         [0024]     The cover of the invention can be treated to control the proliferation of mites and bacteria. For this purpose, the cord that forms part of the cover is treated with an anti-mite and antibacterial product. The cover can be stored unused for a long time without developing bad odours and without becoming a source of proliferation of micro-organisms. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0025]     The present descriptive memory is completed with a set of drawings that illustrate the preferred embodiment of the invention without limiting it in any way.  
         [0026]      FIG. 1  is a schematic representation of the fabric constituted by longitudinal and transverse fibres, as well as of the orientation of the cut.  
         [0027]      FIG. 2  is a perspective view of the cover without being folded and its position on the tyre. The tyre is not shown.  
         [0028]      FIG. 3  shows a representation of an embodiment of the seams in the cover. 
     
    
     PREFERRED EMBODIMENT OF THE INVENTION  
       [0029]      FIG. 1  shows a representation of the fabric ( 1 ) with its fibres arranged longitudinally and transversally.  
         [0030]     On this fabric ( 1 ) a band ( 1 . 1 ) is cut along a 45° angle (α), which is considered most advantageous within the admissible range from 45° to 90°, such that with respect to this band the longitudinal and transverse fibres will now be diagonal.  
         [0031]     The fabric is made of a material with a high tenacity spun from several strands (this example uses from 5 to 9 strands) to provide a sufficiently coarse texture to improve adherence and increase its resistance.  
         [0032]     The fabric ( 1 ) has been manufactured with a surface density from 0.3 to 1 Kg/m2 using taffeta ligament.  
         [0033]     On this fabric ( 1 ) a rectangular oblique cut (α) is made at 45° with a length equal to the perimeter of the cover plus the width of the seam strips and a width greater that that of the tyre.  
         [0034]     Elastic adjusting straps ( 2 ) are incorporated on the sides of the cover that are fitted on either side of the tyre to stabilise the installation.  
         [0035]      FIG. 2  shows dashed and dotted lines ( 1 . 2 ,  1 . 3 ) representing the positional references for the tyre edges.  
         [0036]     The fabric used for the cover is preferably polypropylene due to its high tenacity, its water-repelling properties and recyclability.  
         [0037]     Polypropylene has a low density, less than that of water, so that the cover made with this material has a lower weight than covers with the same volume made with higher density materials.  
         [0038]     In a second example of embodiment the material of the cover is para-aramid fibre, which is very strong, fireproof and corrosion proof.  
         [0039]     In a preferred example of embodiment, the cover can be made of a closed annular piece with a seam ( 3 ) that joins the minor ends of the band ( 1 . 1 ).  
         [0040]     This type of seams ( 3 ) are normally made by overlapping one end on the other, as shown in the top of  FIG. 3 , and constitute the principal breaking point of the cover.  
         [0041]     In the cover of the invention the seam ( 3 ) is made by folding the ends outward and sewing at the points of contact of said ends.  
         [0042]     The bottom part of  FIG. 3  shows the position of the ends of the band ( 1 . 1 ), folded outward at the time of constituting the seam so that this union line is reinforced.  
         [0043]     The piece can be constituted as an open rectangular piece with closure means at its ends.  
         [0044]     These closure means are preferably Velcro strips.  
         [0045]     The essence of this invention is not affected by variations of the materials, shape, size and arrangement of the component elements, described in a non-limiting manner that should allow its reproduction by an expert in the field.