FR2537060A1 - Equipment for a wheel of a self-propelled vehicle intended to increase the adherence of this wheel over slippery, black-iced, snowy or viscous road surfaces, method of manufacturing and installing such an item of equipment. - Google Patents

Abstract

The invention essentially relates to a non-skid system 40 intended to ensure contact with a high coefficient of friction when it is applied with a certain pressure P against a slippery road surface 25 covered with a surface material which is either hard (film 65 of ice 66) or snowy (film of snow 27) or viscous (mud), along a bearing zone of the said slippery surface 25. The strip 40 is noteworthy in that it comprises : - a succession of elastic protuberances 41-42... making between them, and along the length of the strip 40, a hollow reinforcement portion 51-52, - and, moreover, a plurality of hard asperities, especially studs 6, arranged in the said hollow portions 51 of the strip 40. This strip is previously fitted to the tyre 1 of the wheel of a self-propelled vehicle in order to allow movement in winter over all road surfaces. Its advantage is essentially to allow better adherence on not very deep snow whilst preserving the same characteristics on another type of road surface.

Description

The present invention is in the field of devices intended to equip the treads of wheels, in particular driving, of self-propelled vehicles, in order to increase their grip and their road holding on pavements covered on the surface with a slippery material, such as snow, ice or mud
It is customary to equip the treads of automobile tires, using various systems intended to promote the handling of these automobiles.

 Indeed, although on perfectly dry and smooth road the most adherent tires are those which have the smoothest tread, on the contrary, when the roadway is covered with a slippery surface material such as water , snow, ice, mud ..., this tread should be provided with an elaborate structure to maintain a satisfactory grip coefficient of the tire on the road. These wheel equipment are currently very differentiated.

 In this way, when Ilion wishes to obtain a coefficient of adhesion of the wheels on different types of pavement with a different surface finish, it is necessary to change this equipment frequently, as appears in car racing (especially in winter rallies) .

 The most common system consists of the tread of the tires itself, presenting surface sculptures of their rubber very studied to facilitate the flow of the underlying water on wet road, in order to avoid the phenomenon of " 'aquaplanning ".

The tire treads are currently perfectly suited for very high speed use on dry or wet roads.

However, from the moment we move on soils covered with a more viscous surface substrate, everyone has already noticed that conventional tires quickly become ineffective. This is the reason why tire manufacturers have developed:
- on the one hand, tire variants for winter with sculptures
enlarged gum. These tires have enough grip
satisfactory on snow due to the crampon phenomenon
that ensures the intimate cooperation between the erased crenellations
of their tread updated by the sculptures
and the level soil.

- on the other hand, an auxiliary treatment to be subjected to one or
the other of the previous tire categories, consisting
to equip them with a plurality of nails forced into
the gum of the crenellations and whose point protrudes from the envelope
tire tire.

This differentiation between types of tires is extremely painful for users, especially in winter on pavements of different types that change rapidly. Thus an automobile fitted with standard tires with fine tread
- is almost uncontrollable on icy ground,
- loses a large part of its grip on snow-covered soils
and almost instantly gets stuck on loose soil or
muddy.

In addition, the use of specialized tires for snow or mud is unpleasant on open pavement because
- on the one hand, it causes a loss of grip due to a
less surface area of the tire caused by
sculptures themselves, which limits their maximum speed
- on the other hand, it induces hectic vibrations and assour
dissants caused by major discontinuities,
- moreover, it has resistance to good progress
higher blow than conventional tires
- finally studded tires increase these inconveniences and are
of a use to practically proscribe, on cleared road because
. excessively intense vibrations they occasion
come to the car,
damage that it provides to the road,
. of considerable advancement resistance they
impose on the vehicle. As a rule, it is practi
only impossible to drive with an equipped vehicle
studded tires at speeds above 90 km / h.

 In all cases, specialized tires for snow, mud or ice cause an increase in the consumption of the vehicle from 10 to 200%.

Finally, the domestic use of such specialized tires is very painful because it requires, to be versatile, the storage inside the vehicle of one, or even two sets of additional tires. This is both
- very bulky and limits the useful volume of the lockers
vehicle storage,
- and very heavy, which also induces increases in
fuel consumption.

Finally, the exchange of a set of tires
- in the countryside is extremely painful and long because
that it requires lifting the vehicle wheel by wheel and,
moreover, to handle very heavy wheels
- and in the resort, is extremely expensive for the same spoke
sounds.

 To solve these problems, manufacturers have tried to develop more versatile systems. They are auxiliary equipment to be removably adapted to the wheels of vehicles to increase grip under specific road conditions. These are of two different types, but quite similar in their configuration.

 The first type commonly called "chain" is constituted by a series of tortuous metal links, joined by their two ends on two metal hoops to be placed on either side of the wheel; at least one of these hoops being of variable geometry so as to be able to arrange the various links around the periphery of the tread of the tire.

This device is very effective on snow-covered roads. However, as soon as the road clears, it is practically impossible to keep them on the wheels because
- on the one hand, this causes a new intense noise due to the fact
that the various links are not linked to each other,
- on the other hand, it causes unbearable vibrations to
both for the passenger and for the vehicle due to the dice
moment of inertia centers that this causes to
wheels,
- moreover, this induces a considerable increase in the
resistance to vehicle advancement and loss of then
important sance
- finally, the extremely hard protuberances that constitute
the links of the links exceeding very substantially by
the tread cause significant damage
aunts on the floor.

 The second type of more recent use is in a way the variant of "chain" in which the links are replaced by rubberized thongs on the surface of which are planted nails.

 This type of device has exactly the same disadvantages as the above chains, in terms of comfort and road degradation. It certainly provides a very satisfactory grip on icy roads, on the other hand, it is practically ineffective on snow-covered roads.

 In addition, whether it is a chain or removable studs, their structure generally adapted to two circular lateral holding chains is heavy and bulky as well - well in the trunk of a vehicle, as in the garage during storage. 'summer.

In addition, these predominantly metallic structures, rubbing on the ground and in contact with moisture, have a very reduced service life due to rust or wear. Finally, although their structure is adaptable to a certain extent on several types of wheel diameter, by modifying the length of the lateral circular chains, this modularity is very limited by the difficulties in terms of comfort of use which it causes because of
- dangling chains which it requires and which cause
an increase in the noise level and often damage
vehicle wing datings
- and balancing modifications on the road causing
an increase in the vibration rate.

 The object of the present invention is to globally remedy these drawbacks by proposing a new type of tread for self-propelled vehicles, ensuring remarkable grip on pavement as well snowed, icy or muddy.

 A second object of the invention is to provide such a tread formed by the rapid and simple adaptation of a removable anti-slip strip on the tread of conventional tires.

 A third object of the invention is to provide a removable non-slip strip having a very modular character so that it can be mounted on many types of tires regardless of their diameter and their width.

 A fourth object of the invention is to propose various methods of fitting and securing such anti-slip strips on the wheel which ensure perfect support and allow the self-propelled vehicle to run at high speed in comfort of use. maximum.

 A fifth object of the invention is to propose a structure of such an anti-slip strip which considerably limits their weight and their bulk inside the vehicle storage box or during screwing.

 A sixth object of the invention is to propose a particular mode of installation by extremely simple, rapid and effective tensions, and moreover, showing by its simplicity the durability of the anti-slip strips which it equips.

Finally, a seventh object of the invention is to propose an improvement in treads which, while proposing
- smooth advancement in soft snow,
- excellent slip resistance on surfaces
icy or snow-like,
- remarkable flow of fluids on surfaces
wet or muddy.

also allow driving on pavements, especially dry, limiting the damage caused to surface coatings.

 To this end, the invention essentially provides an anti-slip strip intended to ensure contact with a high coefficient of friction when it is applied with a certain pressure against a slippery surface, covered with a surface material as hard, level as viscous. The contact takes place along a bearing zone moving longitudinally on said strip and along a bearing line of the sliding surface. This support zone also has a significant development along the support line.

This non-slip strip is remarkable for the fact that it comprises in combination over its length.
- a succession of elastic protuberances (or at least
vertically), with some trans development
versally to the axis of the anti-slip and sparing strip
between them along the anti-slip strip, a series of
hollow recessed portions, placed opposite said
slippery surface,
- and moreover, a plurality of hard asperities fixed on the
strip, arranged in the hollow parts separating the
protrusions and a height with respect to said points
your troughs lower than those of adjacent protuberances.

 It is easily understood that when this non-slip strip is applied and developed against a hard and slippery surface, such as ice or ice, the pressure of support of the strip on the slippery surface causes successive crushing of each of the protrusions and this makes a projection of the asperities of the envelope of the protuberances which, being freed, from their hollow parts, come to hang against the surface and increase the adhesion of the sliding strip on the latter.

 It is also understood that when this non-slip strip is developed and applied against a surface with a level or viscous appearance, the pressure on the strip causes the material to form and compact, inducing intimate cooperation between the entire support zone of the stressed strip and the surface material. A crampon effect is thus provided by said protuberance.

 Admittedly, one could argue that this structure is close to that constituted by studded tires or removable studs adapted on studded tires. But in fact, it is not.

 On the one hand, it will be noted that within a studded tire or a removable stud, the studs are fixed on the protrusions of the tire or the protrusions formed by the removable crews on the tire and not like the recommends the invention, in the grooves or indentations formed by the tire tread or the removable equipment.

 It is therefore clear that the invention is new in its object.

 On the other hand, the applicant has noticed that the usual arrangement above has a defect on lightly snow-covered roads. In this case, once compacted by the tire pressing pressure on the road, the snow often has a thickness close to that of the studs protruding from the protuberances of the tire or of the removable member adapted to the tire, except that the end of the nails comes to rest on the road and limits the pressure of the conformations of the protuberances or streaks with the snow.

The result
- both degradation of the roadway, especially
starting, nails lightly planted on the surface of the sub
tarred stratum coming into the road,
- and a reduced grip of the tire due to the fact that the effect
protuberance crampon is mitigated by lack of
conformational pressure with snow.

On the contrary, it will be noted that, under these conditions and according to the invention, the pressure on the sliding strip being uniformly distributed both on the crest of the support protuberances, and the function of these protuberances; this is not sufficient to cause the nails to spring from their recess and cause them to spring weakly, so that
- the nails do not reach the roadway, and therefore do not
can degrade it
- and moreover, the compaction of snow in the renfons
cement and between the protrusions, is such that it ensures a
excellent crampon effect and gives perfect grip
of the wheel on the snow-covered road.

The invention therefore provides an indisputable industrial result and
5 new.

To increase the industrial result referred to above, it will be readily understood that it is preferable, according to the invention, to choose a material constituting the elastic protrusions, in such a way that
- when the anti-slip strip is applied under its pres
nominal load against a compact surface, such as a shoe
dry or icy, so that this pressure
nominal either -only applied to the protrusions
bérances, the crushing of the elastic protuberances either
greater than the height which initially separates the envelope
protrusions of 'free extremist nails, so that the
nails get into the ice.

- whereas on the contrary, when the anti-slip strip is
found applied with this nominal pressure against a
muddy or snow-like surface against which pressure no
minale -is distributed at the same time on the crest of the protu
elastic berries and against indentations, crushes
protrusions is less than the recess of the
nails relative to the envelope of the protrusions, this so
that the nails do not come to rest on an underlying pavement.

This provision can, frankly, be implemented
- either by choosing the elasticity of the material accordingly
elastic constituting the protuberances,
- either by playing on the relative surfaces of the protrusions and
recesses, according to a simple rule of three. This
dispositon is within the reach of ordinary skill in the art and will not be
developed
It will also be understood that it is preferable that the distance between two elastic protrusions, along the strip, is less than the development of the support zone 1 in the direction of the line, when the nominal pressure is applied to the strip. This arrangement makes it possible in fact to have two protuberances bearing on the ground when one of the roughness is facing the road.

 Of course, the main use of the anti-slip strip of the invention is to be adapted on at least one wheel of a self-propelled vehicle to facilitate its grip, mainly in winter on pavements whose state of surface is variable, as well icy, snowy as muddy.

 According to a first aspect of the invention, the non-slip strip is produced in a removable modular circular shape, so as to be removably adapted to the circumference of the tread of a wheel.

In this case, it comprises in combination
- a series of adherent modules, arranged side by side such
so that one of their mediating axis, said longitudinal, is
found aligned to constitute the band;
- a set of studs protruding from each attached module
rent, arranged obliquely to the longitudinal axis
of the latter and having a development in the sense
longitudinal of the module which it exceeds, less than the length
as this module so as to spare on one of their
sides at least, a recess.

- a series of asperities made of a hard material exceeding
of each adherent module inside the recess
close to a stud of this module.

and, finally, means of securing the adhered modules
rent relative to each other and subsequently screw
opposite the tread of the wheel on which they
are intended to be adapted.

 According to this variant, the modules have the general shape of a plate, of width greater than that of the tread so as to completely cover it. The sum of the lengths of each module, in their longitudinal direction, is at most equal to that of the perimeter of the circumference of the rolling strip in order to be able to be placed side by side without being uncovered.

 Furthermore, each stud protruding from a module is made of an elastic material allowing it to be crushed frequently without losing its mechanical characteristics.

 Preferably, each adherent module is produced in one piece by molding both the studs and the recesses which they provide between them, using a thermoformable material such as rubber or plastics.

 Asperities are, in turn, preferably made up of conventional "nails", the head of which is included in the material constituting the recesses.

 In general; the establishment of a circular non-slip strip of this type on the tread of a wheel consists in adapting the various modules, spaced apart from each other on the tread, then using means of which various variants will be developed further, to bring them one into the other along their longitudinal axis so that they perfectly fit the tread and are blocked with respect to it.

 According to another aspect of the invention, the anti-slip strip, also removable, intended to be adapted on a wheel, is produced in a monolithic, continuous manner, closed on itself and of diameter slightly less than that of the wheel on which it is intended to be adapted.

 In this case, two particularly quick and simple processes, which will be developed later, can be implemented to perfectly secure the anti-slip strip of the wheel.

 Other characteristics of the invention will emerge from the description which follows with reference to the appended drawings, which description and drawings are given by way of nonlimiting examples.

On these drawings
- Figures 1 and 2 show an evolving ciassic studded tire
tion
. on a snow-covered road (fig. 1)
. and on an icy road (fig. 2)
- similarly Figures 3 and 4 represent in palallíele with the
previous figures, and under the same conditions, the evolutions
a tread conforming to the teachings of the invention
. on a lightly snow-covered road (fig. 3)
. and on an icy road (fig. 4)
- Figure 5 shows a top view, partially broken away,
a variant of adherent modules to make an anti tape
removable circular modular sliding to adapt on the
wheel bearing.

- Figures 6 and 7 respectively represent a sectional view
longitudinal and a transverse lateral view of the anti modules
slip shown in Figure 4.

- Figures 8 and 9 show the essential elements of a dispo
adaptable on the inside (fig. 8) and outside (fig. 9) side
of a wheel to perfectly and quickly secure one by
compared to the other, the various member modules as represented
felt in Figure 4, a modular anti-slip strip according to the in
vention
- Figure 10 shows a continuous monolithic variant of a
circular anti-slip strip to be fitted on the running strip
ment of the tire and shows diagrammatically two processes for perfecting
quickly and quickly adapt it to the tread of a
automobile wheel.

- Figure 77 shows a common tire whose strip of
normal rolling is carried out according to the invention.

- Figure 12 shows an embodiment of modules of the
FIG. 5, the internal face of which (opposite the tire) is provided with
protrusions to mesh on symmetrical protrusions
attached to the tire.

- Figure 13 shows a wheel-tread assembly
according to the invention, in which the wheel-strip connection of
bearing is partially achieved by a gear system
protuberances (sculptures).

 In FIG. 1, we can schematically recognize, in section, a conventional snow tire 1 mounted on a rim 3. Furthermore, it is studded in the usual way using various nails 6 - 7 and 8 ... 12 , distributed around the periphery of its tread 14 and forced into crenellations 16 - 17 - 18 - 22, formed on the tread 14 by updating the tread 24.

 This tire is changing (fig. 1) on a roadway 25 covered with a small film of snow 27. Of course, the tire 1 is turned upside down at a vertical force P resulting from the weight of the vehicle it occupies.

This force P induces a result of pressure applied to the bearing area A of the tire 1 on the roadway 25. Since the tire is rotating along r around its rim 3 secured to a hub (not shown) of the wheel- of an automobile, it is understood that the bearing zone A moves along f longitudinally on the tread 14 of the tire and along a bearing line of the surface of the roadway 25.

 It is noted that under the conditions represented in FIG. 1, the intensity of the pressure is such that it caused sufficient compaction according to t of the thickness of snow 27 so that the nails 6 - 7 - 8 come to bear on the pavement 25. As a result, it can be seen that the pressure caused by pressing the tire 1 on the snow 27 is not maximum in the recesses 26 - 28 - 29 formed by the sculptures 24 between the notches 16-17-18-22 . This disadvantageously limits the grip of the tire 1 on the roadway 25. Furthermore, it can be seen that the ends 36 of the studs 6 come to plow the surface 37 of the roadway 25.

 It is also noted in FIG. 1 that, as is common in tires intended for mixed use, the width and depth of the recesses 26 - 18 - 29 is very small. As a result, there is a slight movement of the studs with respect to the tire 1 during walking and a slight compression and shaping effect of the snow 27 inside the recesses 26 - 28 - 29.

 On the contrary, in Figure 3, we recognize a conventional tire 1 'equipped with a removable non-slip strip 40 according to the invention. The tire 1 'mounted on the rim 3' has extremely fine scultures 42.

 On the other hand, the non-slip strip 40 comprises a succession of high elastic protuberances 41 - 43 ... 45. Between each of these protuberances 41 - 42 develops a deep recess 51 - 52 55. Inside each recess 51 ,, we notice the presence of a nail 58. When this nail is located by rotation of the tire 1 ′, outside of zone A, it appears that the latter is located inside the virtual envelope E of the protrusions 41 - 43 - 45. It is also noted that also inside the bearing area on the snow 27, the protrusions 41 - 43 - 45 are very flattened and therefore strongly compress the snow which is in their recess 51 - 52.

The bearing pressure is distributed both over the surface 62 of the protrusions 41 and that 63 of the recesses 52.

 It will be noted in FIG. 3, that the elasticity of the protuberances 41, their height h, and their surface 62 relative to that 63 of the recesses 52 are such that in the support zone, the nails 6 are nevertheless still in their recess - 52, inside the virtual envelope E of the protrusions 41 and in any case are not in contact with the roadway 25. As a result, i1 clearly appears that the pressure on the snow caused by the transmission of the forces of the force P and the constrictions due to the crushing of the protrusions 42 cause a hardening of the snow and a conformation inside the recesses 52 which induce a very intense crampon effect between the layer of snow 27 and the anti-slip strip 40. 'follows a very effective adhesion of the tread 40 on the snow film 27.

 In FIG. 2, the studded tire 1 is evolving on a roadway 25 covered with a film 65 of ice 66.

 Under the effect of the pressure, the nails 10 - il - 12 successively penetrate into the film 65 of ice 66, until the envelope stops E of notches 16 comes to rest on the surface 70 of the film 65. The driving nails 10 - 11 - 12 into this film causes an effective connection between the tire 1 and the ice film 65.

 A similar result is obtained using an anti-slip strip 40 according to the invention (fig. 4). In this case, we notice that, unlike what happened in a film 27 of snow (fig.

3), 7'pressure force in the support area A is transmitted only on the surface 62 of the protrusions 42 and not on that 63 of the recesses 52. As a result, the crushing of the protrusions 41 is more intense, which causes a spurt of the nails .6 from their recess 52 outside the virtual envelope E of the protrusions 41. In fact, the nails 6 also penetrate into the film 65 of ice 66. The effect of an anti-slip strip according to the invention on ice 66 is therefore exactly the same as that of a studded tire.

It will be noted incidentally that the distance d between two protuberances
successive rances is such that a nail located opposite the roadway 25 in the support zone A, is always located between the two successive protrusions which ensure the effect of "nail sheath" of the invention.

 In FIG. 5 there is a non-slip module 70 intended to constitute by juxtaposition side by side of modules of the same type, a modular modular non-slip strip 72 to be removably adapted to a tire 1 as shown in FIG. 8 and 9 ..

 The structural characteristics of this module 70 will now be detailed.

This has the general shape of a rectangular plate of width
I interior to that I ′ of the tread of the tire 1 on which it is intended to be adapted. According to its axis xx ', the module 70 successively comprises a crampon 75 arranged transversely along yy' then a series of strips 77, 78, 79 arranged parallel along xx 'and adapted by one end 80 on the crampon 75 and by the other end 81 on a crampon 76 parallel to the first.

 Referring to Figures 6 and 7, it appears that the thickness H of the studs 76 is much greater than that of the longitudinal strips 77 - 78 and 79. Because the latter are fixed to the studs 75 - 76 at their lower part 90, the studs 75 therefore protrude from the strips 77 by a height h.

 On each of the strips 77 - 78 - 79 is planted an alignment of nails 6, along the axis xx '. Each of these nails 6 protrudes from its strip 76 - 77 inside the height reinforcement hl. The strips 77 - 78 79 are separated from each other by a recess 95 - 96, made along xx '.

 Furthermore, between each of the nails 6 - 7 is made along yy 'a groove 98, at the upper part of the strip 77. Finally, each of the studs 75 - 76 is extended at each of its ends constituting the corners of the module 70 d 'A strap 100 protruding laterally and provided at its end with a sliding member 102 constituted by a recess 103 of the strap in the longitudinal direction xx' surrounded by a bulge of the strap.

 The cut-away parts 110 - 112 of FIG. 5 and the section of FIG. 6 reveal the internal structure of the module 70. It first appears that each of the nails 6 'pierces a core 116 made of glass fibers. So that the head 117 of the nail is trapped below this core. The module 70 was produced by molding the protrusions 70 and 76 and strips 77 to 79 around the core 116 and the nails 6 'which it supported.

 It will be noted incidentally that the material 120 injected inside the mold to produce the protuberance 76 is different from that 121 injected to produce the strips 79.

 The advantage of this manufacturing method is clearly apparent.

- on the one hand, the core 116 reinforces the modules 70, which are very stressed
during rolling, and secures the various nails 6 - 7
6 '.

- On the other hand we understand that the material 120 is preferred
due to wear and tear against the pavement 25 plus
tenacious as that 121 constituting the strips 79 and in front
very intimately surround the 6 'nails.

 The establishment of a modular tread 72 according to the invention, produced from adherent modules 70, appears in FIGS. 8 and 9. We begin by juxtaposing one next to the other and longitudinally on the strip bearing 14 of the tire 7, a set of six similar modules 70 Then, a metal cable 125 along i is successively introduced inside the recesses 103 of the sliding members 102 of each module 70 located on the rear side of the zone, this cable 125 is terminated at its ends by two rings 126 and 127. Then, the two rings 126 and 127 are joined together and they are brought towards one another by means of a spring 128.

 Furthermore, to secure the various dens 100 located on the front face of the zone, two cables 130 and 131 are used, each terminated by two rings respectively 132 - 133 and 134 - 135. All of the modules 70 which adhere to the tread 14, in two contiguous sections, S1 and 52, comprising approximately the same number of modules, then one passes, using one of the two cables 130 - 131, successively each of the recesses 103 of the sliding members 102 strips 100 belonging to the modules of the same section 51. Crossing in opposite directions with the two ends 132 and 134 of the cables 130 and 131 terminating therein, the sliding members 141 and 142 of the contiguous strips 143 and 144 belonging to the contiguous modules of each section 51 and S2.

Finally, we cross the free ends 132 to 135 of the cables and Iton
thus connects the end 133 of a cable 130 with that 134 of the other by interposing each time a spring 145 - 146. It will be noted
- on the one hand, that the sum of the length L of the modules 70
constituting the modular anti-slip strip 72 surrounding the
tire 1 is slightly less than the perimeter of the tread
ment 14 on which they are adapted,
- on the other hand, that the tightening of cables 125 - 130 and 131
has the effect of bringing one relative to the other, according to
the tread 14 the various modules 70.

 It will also be noted that the extreme edges of each module 70 formed by the studs 75 are raised relative to the average thickness of each module 70 so that two contiguous studs 75 form a stop against each other when their modules 70 are solicited against each other during operation or joining. It appears that this method of joining is at the same time fast, simple, light and resistant. In addition, the various modules 70 each made of reinforced plastic are also excessively resistant and do not fear rust.

 In addition, once disassembled, the anti-slip strip is divided into numerous sub-modules which can be easily stacked and threaded in a box in a reduced footprint to facilitate transport and storage.

 Finally, it appears that once put in place according to these methods, the various modules are both blocked under tension against the tread 14 and blocked against each other, which prevents them from moving around and limits the vibrations- and wear.

 Although this does not appear in FIGS. 8 and 9, it will be understood that the effect of the longitudinal grooves 85 as well as those of the transverse ridges 98 is to promote the flow of fluids in the support zone A. This flow is moreover increased by the fact that the tire tread appears through the recess formed by the longitudinal groove 95. In FIG. 0, a second alternative embodiment of a removable non-slip anti-slip strip is described, but in the monolithic form 150 .This monolithic circular anti-slip strip is in the form of a kind of second tire with an internal diameter of i almost equal to that of the tread of the wheel on which it is intended to be adapted.

 These fundamental characteristics are the same as those developed above; in particular, they comprise a succession of protrusions 41 forming between them - recesses 51 inside which the nails 6 are arranged.

 The variant shown in FIG. 9 uses the same external structural characteristics as that of the module 70. However, it will be noted that this is in no way necessary.

 To promote the maintenance of this strip 150 on the tire 1 mounted on its rim 3, it is nevertheless advisable by the invention to give this strip 150 a longitudinal elasticity allowing it to be stretched circularly. Similarly, it is preferable to provide each of its sides with lateral sidewalls 155 projecting inwards in the direction of the axis zz 'of the strip 150 so as to improve the retention of this strip on the tire 1.

 Two methods are recommended by the invention for adapting the strip 150 on the tire 1 of an inflated vehicle wheel. Both consist first of all in lifting the wheel so as to provide an annular space all around its tread 14.

 According to the first method, the steps of which appear in FIG. 10, the air chamber of the tire 60 is deflated (step a) so as to give the wheel a diameter D 'smaller than that inside D'i of the anti-slip strip 150. Then the wheel is threaded along m (step b) inside the space provided in the anti-slip strip 150 so as to completely cover the tread 14 of the tire using the circular anti-slip strip 150. Finally , the tire inner tube is re-inflated to the correct pressure. According to this process which can be implemented in service stations, the tread 14 of the tire 1 is energetically pinned against the internal face of the non-slip strip stretched radially. This results in an effective joining by friction.

 The second method of fitting the anti-slip strip 150 is shown on the left-hand side of FIG. 9. It consists in biasing radially A according to al, a2, a3 ... the anti-slip strip 150 using spacers. adapted 162 - 163 - 164 ... placed inside and separated from each other circularly. Thus, the non-slip strip 150 is given the inner diameter D 'i greater than the outer diameter D of the tire 1. Then, the tread 14 of the wheel is surrounded by the non-slip strip 150 thus extended. Finally, the anti-slip strip is released so that it applies to the tread. The result obtained is identical to that of the previous process.

 The invention therefore makes it possible, using an excessively simple and inexpensive device, to equip the wheel of a self-propelled vehicle so that it can move under conditions of safety, speed and improved comfort on soils that are snowy, muddy and icy.

We have previously seen two devices for maintaining the tread
- lateral sides projecting 155
- the tread-tire friction resulting from plating
by tensioning the strip on the gong tire.

 Another means can also be used, all of the means proposed by the invention being independent of each other and not exclusive. Thus, according to a variant of the invention, the zone 14 of the tire 1 in contact with the tread 150 can be coated with an anti-slip surface so as to promote the friction force developed between the zone 14 of the band 150. It is in particular advisable to adapt the surface of the strip 150 opposite the zone 14 so as to increase the coefficient of friction.

 This change in overlap of the two surfaces could in particular consist of a coating with a sticky substance or having multiple asperities.

 However, the invention also proposes to use the sculptures in zone 14 to strengthen the maintenance of the tread. To this end, it is necessary to provide, at least in part, the surface of the tread opposite zone 14, with symmetrical treads which, being placed naturally between the corresponding treads of the tire during the plating of the tread against this tire, cause a crampon effect preventing the sliding strip from moving relative to the tire.

 These sculptures on the tread can be produced either on the back of the strips 77 (fig. 7) or by securing part or all of the modules 70 by a surface 166 (fig. 12) in particular of a material commonly used for tires. , surface applied to the face 167 of the module 70 which is not in contact with the ground. This surface 166 is either fixed by various means (riveting bonding) to the face 167, or is optionally an integral part of the module 70.

 FIG. 13 is an example of such an attachment and shows the interlocking of the treads 164 of the tread and 165 of the tire 1 allowing a virtually faultless attachment of the strip to the tire.

 It can therefore be seen that on a tire fitted with such treads, it is possible to adapt very different treads as to their surface in contact with the ground. The invention therefore proposes rather than changing tires as a function of time, to have only a single tire, said to be universal, to which different treads would be applied depending on the state of the roads. In the case of a soil with a viscous or snowy surface, a tread according to the preferred mode of the invention would be necessary. On the other hand, for a dry road, a tread whose external surface would correspond to the surface of the tires used for such a road should be in place.

 Of course, the description of the variants which is made above is not limiting.

 It is in particular possible to produce tires in one piece, the tread of which conforms to the characteristics of an anti-slip strip according to the invention (FIG. 11).

In the same way, although it was advisable according to the invention to overmold the non-slip strip on a reinforcing structure including the nails intended to constitute the asperities, it is also possible
- first of all to conform by injection inside a
mold; the support having a bearing face from which
clears the protrusions, not very wide and arranged to cross
dirty to the support,
- to space these protuberances from each other along the
support so as to provide recesses between them,
- and later plant the nails on the surface of the support
by forcibly introducing their first fixing end in
look of a recess located between two protuberances
neighbors with an intensity such that the other end appears
raises on the surface of said recesses while remaining in
removal of the envelope from the elastic protuberances.

 The invention having now been described and its interest justified in detailed examples, the applicant reserves exclusivity for the entire duration of the patent without limitation other than that of the terms of the claims below.

Claims (33)

1. Anti-slip strip intended to ensure 3 coefficient contact  high friction when applied with some  pressure  against a slippery surface covered with a  both hard, snow-like and viscous surface  - and following a support zone, evolving  + longitudinally on said strip  + and along a support line of said glis surface  health  and having an appreciable development according to said  support line,  said anti-slip strip being characterized in that it comprises  wears in combination over its length  on the one hand, a succession of elastic protuberances,  . having a certain development, transversely to  the axis of the anti-slip strip,  and sparing between them and along the anti-slip strip  a hollow recess, placed in  look of said slippery surface,  - and on the other hand, a plurality of hard asperities  . arranged in said hollow parts of the strip  separating the protrusions  . and height with respect to said lower hollow part  greater than that of said adjacent protuberances,  so that  - when said anti-slip strip is applied and developed  against a hard, slippery surface, the contact pressure  of the strip on said surface causes crushing  successive of said protuberances, and the attachment of aspheres  tees, released from their hollow parts against said surface,  - and on the other hand, when said anti-slip strip has become  coiled and applied against a level surface and / or screw  queuse, the pressure on the strip causes, by conformation,  intimate cooperation between the entire support area  of the stressed strip and the surface material constituting  said surface yliss3n1 :: e, a crampon effect being thus  provided by said protuberances. 2. Anti-slip strip, according to claim 1 above,  intended to be applied with a certain nominal pressure against  a surface and characterized in that  - On the one hand, the elastic material constituting said protu  berances  - on the other hand, the ratio of surfaces between its protuberans  these and its recesses  is such that  - when said anti-slip strip is applied and developed  swords against a compact and hard surface in such a way  that the nominal pressure is only applied to the  surface of the ridges of the protuberances in support, the crushing  of said protrusions is greater than the height which separates  initially the envelope of the protrusions of the free end  nails, so that the nails protrude from the protrusions and  penetrate into said surface,  - and on the contrary when said anti-slip strip is  found applied under said nominal pressure against a level or muddy surface in such a way that:  nominal pressure is distributed over both the surface of the  protrusions and indentations, crushing pro  is less than the recess of the nails by  relative to the envelope of the protrusions so that the  nails do not come to rest on the underlying support of the  snow-like or muddy surface material. 3. Anti-slip strip according to one of claims 1 and 2 above  teeth applied with a certain pressure - against a surface  sliding in a bearing area, said non-slip strip  being characterized in that the distance between two of its said  elastic protrusions, along the strip is less than  development of said support zone in the direction of the support line. 4. Removable modular circular anti-slip strip, according to one  of claims 7 to 3 above, intended to be adapted on  the circumference of the tread of a wheel (in particular  drive) of a self-propelled vehicle to facilitate grip  this wheel on slippery roads as well glazed,  snowy than muddy,  said sliding strip being characterized in that it com  door in combination  - a series of member modules,  having the general shape of a plate,  whose sum of lengths is at most equal to  perimeter of the circumference of said rolling strip  is lying  arranged side by side in such a way that one of their  median axes, said longitudinal is aligned, for  constitute said band,  - at least one crampon  made of elastic material  exceeding each said member module,  arranged obliquely (and in particular perpendicularly)  with respect to said longitudinal axis of each module  said spike having a development along said axis  longitudinal less than the length of the adherent module  of which it exceeds, so as to spare at least one ren  darkly on one of its sides along said longitu axis  dinal  - at least asperity  carried out in. hard material  and exceeding  + of each said adherent module, from within a  said recess bordering a spike of this  module,  more than a height, relative to the bottom of said renfon  cement, lower than that of the neighboring stud  - and finally, means for securing said adhered modules  rents-- one relative to another and vis-à-vis the band of  wheel bearing. 5. Modular circular anti-slip strip removable according to the  previous claim 4, characterized in that  - on the one hand, the sum of the lengths of said modules con  stituant is little less than the perimeter of the strip of  bearing on which said anti-slip strip is intended  born to be adapted  - and on the other hand, said member modules are provided with  means of bringing each other together, according to them  longitudinal axis, extreme edges of neighboring modules  so as to allow easy blocking of said modules one by  compared to others on said tread. 6. Modular circular anti-slip strips removable according to one  of preceding claims 4 to S, characterized in that the  extreme edges along said longitudinal axis of each of its said  adherent modules is raised above the average thickness  of each module so that said extreme edges of  two of these adherent modules form a bumper when their  modules are requested from each other during operation  ment and / or solidarity. 7. As a new application of a known means, anti-slip tape  circular, modular, removable according to one of the resi  cations 3 to 5 above, constituted by the juxtaposition end to end  end, closed on itself, of a series of adherent modules,  these modules being each provided,  - at their extreme corners  - straps projecting laterally and fitted at their ends  free of a sliding member,  said anti-slip strip being characterized in that said  means of securing its modules consist of at  minus a strap  - closed on itself,  - introduced successively and freely inside the said  sliding members of successive strips arranged  on the same side of the longitudinal axis of said modules  - and provided at its ends with means for shortening  its perimeter  so that  - said modules can be easily arranged on said  tread, in position separated from each other,  while said approximation means are deactivated  - but that once in place on said tread, these  said modules can be brought together  in the direction of the rolling band, by tightening  of said shortening means. 8. Removable circular anti-slip strip, according to one of the reven  dications 1 to 3 above, characterized in that it is  - monolythic and continuous  - closed in on itself  - and of diameter almost equal to that of the tread  ment of the wheel on which it is intended to be adapted. 9. Removable monolythic circular anti-slip strip, depending on the  previous claim 8 characterized in that it has a  transverse elasticity allowing it to be stretched circularly 10. Anti-slip, circular, monolithic strip removable according to  one of claims 8 and 9 above, characterized in that  that it is provided on each side with lateral flanks projecting  inward towards the winding axis of said  bandaged. 11. Method for installing a non-slip, circular, monoly strip  removable theme according to one of claims 9 to 10 preceding  tes, on the tread of a tire; with inflated air chamber,  mounted on a wheel,  said process being characterized in that  - said wheel is raised so as to provide an anu space  laire all around its said tread,  - the air chamber of the tire is deflated, so as to give  the wheel an outside diameter smaller than that, inside, of  said anti-slip strip,  - Iron completely covers the tread 'of the tire to  using said circular anti-slip strip,  - then the tire inner tube is re-inflated to the pressure  adapted.  secured to the tread by friction.  internal of said non-slip strip thus stretched radially and  so as to press the tread of the tire against the face 12. Method for installing a monolithic circular anti-slip strip  extendable removable according to claim 9,  said process being characterized in that  - we lift said wheel so as to manage an annu space  all around its so-called% oulement strip  - Solicitates radi3; e! nent said anti-slip strip so as to  give it an interior d aneter greater than that, exterior,  .of the wheel,  - said wheel tread is surrounded with the aid of  the anti-slip strip thus extended,  - finally, the anti-slip strip is released so that  that it retracts on said tread. 13. Anti-slip strip according to one of claims 1 to 70 above  teeth characterized in that between two so-called protuberances  neighboring elastics, are placed at least two alignments of  so-called hard asperities,  - sensitively developed along the longitudinal axis of the strip,  - and separated from each other by at least one groove  longitudinal  practiced at the bottom of said recess between the two  protuberances  and substantially oriented along the longitudinal axis of  said strip, almost parallel to said alignments  harsh asperities 14. Anti-slip strip according to claim 13 above, charac  in that it also has transverse ridges  - formed between two asperities of a said alignment  - and joining a said longitudinal groove at a lateral edge  of said anti-slip strip 15. Removable circular anti-slip strip according to one of the reven  dications 13 and 14 above, consisting of a ribbon, closes  on itself, to adapt on the circumference of the strip of  wheel bearing,  said tread being characterized in that its said  lines of hard asperities are arranged on strips  - developed substantially longitudinally between two so-called  neighboring elastic protuberances,  - and separated from each other by at least one recess  substantially longitudinal leaving ;; appear part of the  wheel tread when said anti-slip strip  suitably. 16. Anti-slip strip according to one of claims 7 to 10 and 13 to  15 previous, characterized in that its said protuberances  elastic consist of a material of a different nature than  that constituting the substrate of said underlying recesses  with harsh asperities. 17. Anti-slip strip according to claim 16 preceding character  laughed at in that its said protuberances consist of a  more tenacious material than that constituting the substrate of said  indentations underlying said hard asperities. 18. Tire with a tread conforming to the characteristics  of an anti-slip strip as described in one  of claims 1, 2, 12, 13, 15 and 16. 19. Method for manufacturing a portion of anti-slip strip according to  one of claims 1 to 3 characterized in that  - conform by injection (in particular of rubber material  tee or plastic) inside a mold, a long support  line presenting a bearing face from which one releases  protuberances  not wide  arranged transversely to said support,  - we space these protrusions from each other along  of said support so as to form between them reinforcements  cements,  - we plant a plurality of nails  on the surface of said strip  by forcing  * a first end for fixing these nails in  look of a said recess located between two  neighboring protuberances  + with an intensity such as the other end,  pointed and hard, protrudes from the bottom of said recess  while remaining behind the envelope  said elastic protrusions. 20. Method for manufacturing a portion of non-slip strip according to  claim 1 to 3, characterized in that  - we constitute a soul by overcoming it on one of its  faces, of a plurality of hard asperities1 in particular of nails,  - it is molded around this core and on the same side as said  asperities, the succession of protuberances and indentations  characteristics of said strip, so that  the free ends of at least some of the rough edges  protrudes from the bottom of the bulges but. but remains behind the envelope of the protuberances 21. Process according to one of the preceding claims 19 and 20 of  manufacture by molding of an anti-slip strip according to one of the  claims 15 to 16  said process being characterized in that two mate are injected  rials of different nature inside the conformation mold,  - one facing the imprint of said protuberances  - and the other opposite the imprint of said recesses. 22. Member module intended to constitute, in cooperation with others  modules of the same type, a modu circular anti-slip strip  demountable according to one of claims 4 to 7, to be adapted  on the tread of a wheel, in particular a driving wheel, of a  self-propelled vehicle to facilitate the grip of this wheel on  slippery roads as well glazed, snowy as  muddy, this module having the general shape of a plate of  width 9 greater than that of the tread of said  wheel,  said adherent module being characterized in that it comprises on  one of its so-called adherent faces  - at least one crampon  made of elastic material  protruding from said adherent face of the module  - having an appreciable development, in a  oblique (and in particular perpendicular) direction by  relation to the longitudinal axis of the module,  said spike having a development, according to said  longitudinal axis, less than the module length, c ', e  so as to provide at least one recess on one of  its sides, along said longitudinal axis,  - at least asperity  . made of hard material  and exceeding  + of said adherent face, inside the recess  lying in the vicinity of said spike,  more than a height, relative to the bottom of said renfon  cement, lower than that of the neighboring stud  - means for securing said adherent module vis-à-vis  of module of the same type within said non-slip strip  modular 23.Fixing method on the tread of a wheel, a  circular modular non-slip strip according to claim 7,  using two cables and at least one tensioning system, said  process, consisting first of all in setting up the various  adherent modules on the tread, being characterized by  what  - We divide all the modules of the anti-slip strip  in two junctional sections with approximately the same name  number of modules,  - then we cross each of said sliding members  said strips of modules of the same section with a  of the two cables,  - we cross in opposite direction with the two ends of  cables leading to it, said sliding members of the  two pairs of contiguous straps belonging to the modules  external joints of each section,  - finally we cross the free ends of the cables and connect  the free end of a section cable with the free end  on the other by interposing at least one tension system. 24. Wheel of a vehicle which serves at least in part as contact for  less partial between this vehicle and the ground when said vehicle is  normally travels including the following  in combination  - a rim acting as a junction between said wheel and said  vehicle  a compound tire  an inflatable envelope circularly arranged around  of said rim, integral with it and having a role  air damper vis-à-vis the vehicle  a sufficiently rigid envelope  + which can in particular be said inflatable envelope,  + and which otherwise covers said inflatable envelope and  is integral with said rim.  wheel fitted with a common tire.  The entire semi-rigid envelope in the case of a  bearing in case. wear instead of having to change  . we are able to easily change this so-called strip of  only this so-called tread wears out  rolling  . the role of adhesion by contact is entrusted to said strip  said semi-rigid envelope so that  dariser and to dissociate said tread from  - reversible fastening means allowing soli  ground when the vehicle is moving normally  said semi-rigid envelope is no longer in contact with the  less partially the semi-rigid envelope so that  - a removable tread circularly covers the  said wheel being characterized in that  at least the first three functions are fulfilled,  - a role of grip on the ground by contact surface with the ground  - a role of grip on the ground by stiffening  - a role of shock absorber by the inflatable envelope  - a role of junction of the wheel to the vehicle by the rim  vis-à-vis said vehicle namely  so that among the 4 necessary functions of said wheel  inflatable allows said vehicle to have better adhesion as I know the skilled person  which by at least partially stiffening said envelope 25. Process for intermittent modification of the contact surface with  the ground of a vehicle wheel,  - this wheel being in a main initial composite phase  ment of the following known combination  . a rim  a semi-rigid casing secured to the rim  - the semi-rigid envelope of said wheel being in the phase  initial in contact with the ground by its external face when the  vehicle moves normally, so that in- phase  initial the contact surface of said wheel is the face ex  dull of said semi-rigid envelope  said process being characterized in that,  - when the contact surface with the ground is modified  of said wheel  at least partially covering said semi envelope  rigid by an auxiliary tread so  that said outer face of said semi envelope  rigid is no longer in contact with the ground when the  vehicle is moving normally  said auxiliary tread is secured to  said semi-rigid envelope so that  + during normal movement of the vehicle the belt  auxiliary bearing remains fixed relative to the  tire  + when the vehicle is moving normally the face  external of said semi-rigid tire casing is  pius in contact with the ground  + the new contact surface with the ground of said  wheel is the outer face of said strip of  auxiliary bearing - when changing the contact surface later  with the ground of said wheel, modification resulting in particular  wear of said auxiliary tread  the auxiliary tread is separated from  said wheel  the auxiliary tread is disengaged from said  wheel so that if the vehicle normally rests on  the ground, the external face of said semi-rigid envelope  of said wheel is partly again in contact with  floor  at least partially covering said semi envelope  rigid by an auxiliary tread which can  particular be the old auxiliary tread  so that said outer face of said envelope  semi-rigid frame no longer in contact with the ground  when the vehicle is moving normally  the auxiliary tread is secured to  said semi-rigid envelope so that  + during normal movement of the vehicle the belt  auxiliary bearing remains fixed with respect to  said semi-rigid envelope  + the new contact surface with the soil of said  wheel is the outer face of said strip of  auxiliary bearing - when f'etour'ii the initial ground contact surface of said wheel  the auxiliary tread is separated from  said semi-rigid envelope  disengage the outer tread of said  wheel so that when the vehicle rests normal  lie on the ground the contact surface with the ground of  said wheel is again partly the outer face  of said semi-rigid envelope. 26. Method of manufacturing a wheel and an auxiliary belt of  bearing, suitable for method 25, wheel mainly composed of  the combination, itself known,  - a rim  - a semi-rigid casing secured to said rim  said process being characterized in that  - Protrusions are made integral with the external face of  said semi-rigid envelope,  - protuberances are made integral with the inner face  of said auxiliary tread, face not being  normally in contact with the ground  - we adapt your protrusions of said outer face to  protrusions of said inner face so that they mesh  ent at least in part during the application of method 25 in  so that the joining of said tread  auxiliary and said semi-rigid envelope is made at  less in part  by this meshing  by the resulting crampon effect. 27. Method for manufacturing a suitable auxiliary tread  to the application of the method 25 characterized in that  - at least partially covering the inside of the  auxiliary tread in contact with the outer face  of said semi-rigid envelope, by a layer of  non-slip product and in particular a micro layer  roughness or a layer of adhesive. 28. Method of manufacturing a wheel adapted to the application of  method 25, characterized in that  - at least partially covering the external face of said  semi-rigid envelope, which during a moo'iflcation of the  the ground contact surface of said wheel is covered with  less in part by said auxiliary tread,  a layer of non-slip product and in particular a  layer of micro-roughness or adhesive. 29. Wheel according to claim 24 characterized in that  - protuberances are integral with the external face of said  semi-rigid envelope  - protrusions are integral with the inner face of  said auxiliary tread which covers said face  external of said semi-rigid envelope during application  of method 25,  * and the protrusions of said external face mesh  at least partly in the protuberances of said face  interior during application of process 25  . so that one of the means of securing said  auxiliary tread to said tire is constituted  by said meshing from which a crampon effect results  of solidarity. 30. Wheel according to claim 24 characterized in that  - a layer of non-slip product, in particular made up  a layer of micro-roughness or a layer of adhesive  is integral with the inner face of said rolling strip  auxiliary ment which covers the external face of said  semi-rigid envelope so that one of the means of so  securing said auxiliary tread to said  rigid envelope is constituted by this so-called layer which  prevents said auxiliary tread when it is  solicited by efforts to slide on said envelope  semi-rigid. 31. Wheel according to claim 24, characterized in that  - a layer of non-slip product, in particular consisting of  a layer of micro-roughness or a layer of adhesive,  is integral with said external face of said semi envelope  rigid so that one of the means of securing the  said auxiliary tread to said semi envelope  rigid is constituted by this said layer which prevents said  auxiliary tread when requested by  efforts to smooth it over said semi-rigid envelope. 32. Auxiliary tread adapted to a wheel according to the revenue  dication 28 characterized in that it comprises  - an elastic part  - means of closure, in particular permanent  - a perimeter less than the perimeter of said envelope  rigid so that  by expanding sufficiently as a result of said elas part  ticks said auxiliary tread, its perimeter  becomes at least equal to the outer perimeter of said  semi-rigid envelope  one of the means for securing said strip of  auxiliary bearing to said semi-rigid casing is  constituted by said elastic part which by the force of  elastic reminder that it generates when said strip of  auxiliary bearing covers said semi envelope  rigid, considerably increases the friction forces  ment of said auxiliary tread on said  rigid envelope. 33. Process for intermittent modification of the contact surface with  the ground of a vehicle wheel, a wheel produced in accordance with the claim  tion 24  - the semi-rigid envelope of said wheel being in the phase  initial in contact with the ground by its external face when the  vehicle is moving normally, so that in the phase  initial the contact surface of said wheel is the face ex  dull of said semi-rigid envelope  said process being characterized in that,  - when the contact surface with the ground is modified  of said wheel  at least partially deflate said tire  at least partially covering said semi envelope  rigid by an auxiliary tread so  that said outer face of said semi envelope  rigid is no longer in contact with the ground when the vee  hicule moves normally  said auxiliary tread is secured to  said semi-rigid envelope and said tire is re-inflated,  the solidarity which may in particular result from the recovery  flage so that  + during normal movement of the vehicle the belt  auxiliary bearing remains fixed relative to the  tire  + when the vehicle is moving normally the face  external of said semi-rigid tire casing is  more in contact with the ground  + the new contact surface with the ground of said  wheel is the outer face of said wheel band  auxiliary element - when the contact surface is subsequently changed  with the ground of said wheel, modification resulting in particular  wear of said auxiliary tread  . we deflate said tire  . the auxiliary tread is separated from  said wheel  . the auxiliary tread is disengaged from said  wheel so that if the vehicle normally rests on  the ground, the external face of said semi-rigid envelope  of said wheel is partly in contact again with  floor  . at least partially covering said envelope  rigid by an auxiliary tread which  may in particular be the old tread  auxiliary so that said outer face  of said semi-rigid envelope is no longer in  contact with the ground when the vehicle is moving normally  . said auxiliary tread is secured to  said semi-rigid envelope and we re-inflate said  tire, the connection may in particular result  re-inflation so that  + during normal movement of the vehicle the  auxiliary tread remains fixed by  compared to said semi-rigid envelope  + the new contact surface with the ground of  said wheel is the outer face of said  auxiliary tread - when returning to the initial ground contact surface of  said wheel  . we deflate said tire  . the auxiliary tread is separated from the  said semi-rigid envelope  . disengage the outer tread of said  wheel so that when the vehicle rests normal  lie on the ground the contact surface with the ground of  - said wheel is again partly the outer face  of said semi-rigid envelope.