Title of Invention	"RUBBER COMPOSITION USABLE IN THE VULCANISED STATE AS A TYRE SAFETY SUPPORT AND SUCH A SUPPORT"
Abstract	A rubber composition, usable in the vulcanised state as a safety support (1) intended to be mounted on a wheel rim inside a tyre, so as to be capable of supporting a tread of said tyre in the event of a drop in inflation pressure, wherein said support (1) consists of a vulcanised rubber composition characterised in that said composition comprises: (phr: parts by weight per 100 parts of diene elastomer(s)): natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr, more than 60 phr of a reinforcing white filler, and from 3 to 8 phr of sulphur.

Title of Invention

"RUBBER COMPOSITION USABLE IN THE VULCANISED STATE AS A TYRE SAFETY SUPPORT AND SUCH A SUPPORT"

Abstract

A rubber composition, usable in the vulcanised state as a safety support (1) intended to be mounted on a wheel rim inside a tyre, so as to be capable of supporting a tread of said tyre in the event of a drop in inflation pressure, wherein said support (1) consists of a vulcanised rubber composition characterised in that said composition comprises: (phr: parts by weight per 100 parts of diene elastomer(s)): natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr, more than 60 phr of a reinforcing white filler, and from 3 to 8 phr of sulphur.

Full Text	The present invention relates to a safety support (1) intended to be mounted on a wheel rim inside a tyre, wherein said support (1) consists of a vulcanised rubber composition comprising (phr means parts by weight per 100 parts of diene elastomer(s)): natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr, more than 60 phr of a reinforcing white filler, and from 3 to 8 phr of sulphur.The present invention relates to a rubber composition usable in the vulcanised state as a safety support intended to be mounted on a wheel rim within a tyre, to such a support capable of supporting a tread of said tyre in the event of a drop in inflation pressure and to a mounted assembly comprising this support. In known manner, safety supports for vehicle tyres are intended to be mounted on a rim within the tyre for the purpose of being capable of supporting the tread of this tyre in the event of a loss of inflation pressure. These supports in particular comprise a base which is intended to conform to the rim and a crown which is intended to come into contact with the tread in the above-stated event and which leaves a clearance relative thereto at nominal pressure. Japanese patent specification JP-A-3782601 proposes such a support, the base and crown of which are substantially cylindrical and which moreover comprises an annular body connecting said base and said crown. This annular body comprises a supporting element which is continuous circumferentially and which comprises: • a plurality of partitions extending axially on each side of said circumferential median plane and distributed around the circumference of said support, and • joining elements extending substantially circumferentially, each joining element connecting the respective ends of two adjacent partitions which are arranged on the same side of the support, said joining elements being arranged alternately in succession on each side of said partitions; in which the partitions and joining elements are substantially rectilinear and the difference between the maximum and minimum values of the area of an axial section of the support element as a function of the azimuth, relative to the sum of these same areas, is preferably less than 0.3. As a consequence, as a function of the azimuth, the area of an axial section of the support element varies at most by a factor of two in order to ensure good uniformity of loading capacity and to limit vibration when running on the support. This support is essentially produced using a hard polymeric material and the whole supporting element is designed to withstand compressive loads. Such supports may be produced in conventional manner, for example by injection moulding. The object of the present invention is to provide & rubber composition, usable in the vulcanised state as a safety support intended to be mounted on a wheel rim inside a tyre, which composition is such that, at a comparable flat running service life, the weight reduction performance for said support is further improved. To this end, a rubber composition according to the invention is such that it comprises (phr: parts by weight per 100 parts of diene elastomer(s)): - natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr, - more than 60 phr of a reinforcing white filler, and - from 3 to 8 phr of sulphur. It will be noted that the invention relates to rubber compositions in both the non-vulcanised state and the vulcanised state. With regard to said elastomer(s), a diene elastomer is taken to mean an elastomer obtained at least in part (i.e. a homopolymer or copolymer) from diene monomers (conjugated or unconjugated monomers bearing two double carbon-carbon bonds). Preferably, it will be noted that said elastomers are constituted by at last one essentially unsaturated diene elastomer. An essentially unsaturated diene elastomer is taken to mean a diene elastomer which is obtained at least in part from conjugated diene monomers having a content of moieties or units of diene origin (conjugated dienes) which is greater than 15% (mol%) and, for example: a) any homopolymer obtained by polymerisation of a conjugated diene monomer, such as 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-di(Cl to C5 alkyl)-1,3-butadiene, such as for example 2,3-dimethyl-l,3-butadiene, 2,3-diethyl-l,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene. b) any copolymer obtained by copolymerisation of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds, such as styrene, ortho-, para- or meta-methylstyrene. Butadiene-styrene copolymers, or butadiene-isoprene copolymers may be mentioned by way of example. According to one embodiment of the invention, said composition also comprises a homopolymer obtained by polymerisation of a conjugated diene monomer having 4 to 12 carbon atoms, or a copolymer obtained by copolymerisation of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms, in a quantity of less than or equal to 40 phr. Said composition accordingly comprises, for example, a blend of natural rubber and polybutadiene. According to another embodiment of the invention, said composition comprises a single diene elastomer entirely consisting of natural rubber or synthetic polyisoprene. A reinforcing white filler is taken to mean a white filler which is capable, on its own, without any intermediate means other than a white filler/elastomer bonding agent, of reinforcing a rubber composition intended for the manufacture of tyres, in other words which is capable of replacing the reinforcement action of a conventional filler of tyre-grade carbon black. Such a reinforcing white filler may, for example, consist of silica and is advantageously present in said composition in a quantity between 60 and 80 phr and, still more preferably, in a quantity between 65 and 75 phr. Suitable silicas which may be used are any precipitated or pyrogenic silicas known to the person skilled in the art, the BET or CTAB surface area values of which are both within a range from 50 m2/g to 200 m2/g, with highly dispersible precipitated silicas being preferred. "Highly dispersible silica" is understood to mean any silica having a very substantial ability to disagglomerate and to disperse in an elastomeric matrix, which can be observed in known manner by electron or optical microscopy on thin sections. Non-limitative examples of such highly dispersible silicas usable for the invention which may, for example, be mentioned are silicas BV 3370 and BV 3380 from Degussa, silicas Zeosil 1165 MP and 1115 MP from Rhodia, silica BXR 160 from PPG or silica Zeopol 8745 M from Huber. Preferably, a silica is used, the BET or CTAB surface area values of which are both in the range between 110 and 200 m2/g and, still more preferably, between 140 and 195 m2/g. The physical state of the silica is immaterial, whether it be in the form of a powder, microbeads, granules, balls. Silica is, of course, also taken to mean blends of different silicas. The silica may be used alone or in the presence of other white fillers. The CTAB specific surface area value is determined in accordance with the method of Standard NFT 45007 of November 1987. The BET specific surface area value is determined in accordance with the method of BRUNAUER, EMMETT and TELLER, which is described in "The Journal of the American Chemical Society, vol. 60, p. 309 (1938)" and corresponds to Standard NFT 45007 of November 1987. The following are non-limiting examples of reinforcing white fillers which may also be used: - aluminas (of the formula Al2O3), such as the high dispersibility aluminas which are described in European Patent Specification EP-A-810 258 or alternatively - aluminium hydroxides, such as those described in international patent specification WO-A-99/28376. It will be noted that the composition of the invention could comprise carbon black in addition to said reinforcing white filler, for example in the form of a carbon/silica blend. The rubber composition according to the invention moreover conventionally comprises a reinforcing white filler/elastomer bonding agent (also known as a coupling agent), the purpose of which is to provide an adequate chemical and/or physical bond (coupling) between said white filler and said elastomer(s) while facilitating dispersion of this white filler within the latter. Such a bonding agent, which is at least bifunctional, has, for example, the simplified general formula "Y-T-X", in which: -Y represents a functional group ("Y" function) which is capable of bonding physically and/or chemically with the white filler, such a bond being able to be established, for example, between a silicon atom of the coupling agent and the hydroxyl (OH) surface groups of the filler (for example, surface silanols in the case of silica), -X represents a functional group ("X" function) which is capable of bonding physically and/or chemically with the elastomer, for example by means of a sulphur atom; -T represents a hydrocarbon group making it possible to link Y and X. These bonding agents must in particular not be confused with simple agents for coating the filler in question which, in known manner, may comprise the Y function which is active with respect to the filler but are devoid of the X function which is active with respect to the elastomer. Such bonding agents, of variable effectiveness, have been described in a very large number of documents and are well-known to the person skilled in the art. In fact, it is possible to use any bonding agent which is known to or likely to ensure, in the diene rubber compositions usable for the manufacture of tyres, effective bonding between the silica and diene elastomer, such as, for example, organosilanes, in particular polysulphurised alkoxysilanes or mercaptosilanes. In particular polysulphurised alkoxysilanes are used, such as are described, for example, in patent specifications US-A-3 842 111, US-A-3 873 489, US-A-3 978 103, US-A-3 997 581, US-A-4 002 594 or, more recently, US-A-5 580 919, US-A-5 583 245, US-A-5 663 396, US-A-5 684 171, US-A-5 684 172 and US-A-5 696 197, which describe such known compounds in detail. Particularly suitable for the composition of the invention, without the definition below being limitative, are so-called "symmetrical" polysulphurised alkoxysilanes which satisfy the following general formula (I): (I) Z-A-Sn-A-Z, in which: - n is an integer from 2 to 8 (preferably from 2 to 5); - A is a divalent hydrocarbon radical (preferably C1-C18 alkylene groups or C6-C12 arylene groups, more particularly C1-C180 alkylenes, in particular C2-C4 alkylenes, in particular propylene); - Z corresponds to one of the formulae below: (Formula Removed) in which: - the radicals R1, which may or may not be substituted, and may be identical or different, represent a C1-C18 alkyl group, a C5-C18 cycloalkyl group, or a C6-C18 aryl group (preferably C1-C6 alkyl groups, cyclohexyl or phenyl, in particular C1-C4 alkyl groups, more particularly methyl and/or ethyl); - the radicals R2, which may or may not be substituted, and may be identical or different, represent a C1-C18 alkoxyl group or C5-C18 cycloalkoxyl group (preferably C1-C8 alkoxyl groups or C5-C8 cycloalkoxyl groups, more particularly methoxyl and/or ethoxyl). In the case of a mixture of polysulphurised alkoxysilanes corresponding to the formula (I) above, in particular conventional commercially available mixtures, it will be understood that the mean value of "n" is a fractional number, preferably varying between 2 and 5. Polysulphurised alkoxysilanes which may more particularly be mentioned are polysulphides (in particular tetrasulphides) of bis(alkoxyl(C1-C4)silylpropyl), in particular of bis(trialkoxyl(C1-C4)silylpropyl), in particular polysulphides of bis(3-trimethoxysilylpropyl) or of bis(3-triethoxysilylpropyl). Among these compounds, bis(3-triethoxysilylpropyl) tetrasulphide, abbreviated TESPT, of the formula [(C2H5O)3Si(CH2)3S2]2, is preferably used, which is sold, for example by Degussa under the name Si69 (or X50S when supported at a content of 50 wt.% on carbon black) or alternatively by Witco under the name Silquest A1289. The person skilled in the art will be able to adjust the content of coupling agent in the compositions of the invention, according to the intended application, the elastomer(s) used and the quantity of reinforcing white filler used. In the rubber compositions according to the invention, the content by weight of coupling agent may be within a range from 2 to 15% relative to the mass of reinforcing white filler, and, preferably, within a range from 5 to 12%. With regard to the sulphur content in the composition according to the invention, it will be noted that it may preferably vary from 4 to 6 phr. The rubber compositions according to the invention contain, apart from said elastomer(s), said reinforcing filler, sulphur and one or more reinforcing white filler/elastomer bonding agent(s), all or part of the other constituents and additives usually used in rubber mixtures, such as plasticisers, pigments, antioxidants, vulcanisation accelerators, extender oils, one or more agents for coating the reinforcing white filler, such as alkoxysilanes, polyols, amines etc.. According to another feature of the invention, said rubber composition exhibits an M10 elasticity modulus at 10% deformation which is greater than 10 MPa, advantageously greater than 12 MPa and is preferably between 13 and 20 MPa. The vulcanised rubber composition according to the invention is prepared using three successive preparation stages in accordance with a procedure familiar to person skilled in the art: - a first thermomechanical working or kneading stage (sometimes known as the "non productive" stage) at elevated temperature, up to a maximum temperature between 130°C and 200°C, preferably between 145°C and 185°C, during which all the necessary constituents including the coupling system according to the invention, any optional filler coating agents or complementary processing agents and various other additives, with the exception of the vulcanisation system, are introduced, for example, into an appropriate mixer, such as a conventional internal mixer; - a second mechanical working stage (sometimes known as the "productive" stage) at lower temperature, typically below 120°C, for example between 60°C and 100°C, the finishing phase during which the crosslinking or vulcanisation system is incorporated; such stages are described, for example, in patent specification EP-A-0 501 227, and - a third vulcanisation stage of the mixture obtained on completion of the second stage. A safety support according to the invention is such that it consists of said rubber composition of the invention. This support according to the invention is, for example, of the type comprising: - a substantially cylindrical base, intended to conform to the rim, - a substantially cylindrical crown intended to come into contact with the tyre tread in the event of a drop in pressure and to leave a clearance relative to said tread at nominal pressure, and - an annular body connecting said base and said crown together, said body comprising a circumferentially continuous supporting element with a circumferential median plane, said supporting element comprising a plurality of partitions extending axially on each side of said circumferential median plane and distributed around the circumference of said support. According to a first embodiment of this example of a support according to the invention, said annular body also comprises, on one of said sides of the support, joining elements extending substantially circumferentially, each joining element connecting the respective ends of two adjacent partitions which are arranged on the said side of the support, said joining elements being arranged alternately in succession on each side of said partitions. In this first embodiment, said joining elements are mutually supported between two adjacent partitions by a rib extending from said crown to said base of the support such that said joining elements form a continuous joining wall in the form of a gusset all along said side of said support. More precisely, said joining wall comprises a plurality of cells, each of which is delimited by two adjacent ribs, the bottom of each cell substantially exhibiting a dihedral shape, the ridge of which is formed by one of said partitions and the faces of which are respectively formed by said alternate joining elements. According to a second embodiment of this example of a support according to the invention, said annular body also comprises, on both sides of the support, joining elements extending substantially circumferentially, each joining element connecting the respective ends of two adjacent partitions which are arranged on the same side of the support, said joining elements being arranged alternately in succession on each side of said partitions. In this second embodiment, said partitions are modified in the central portion thereof relative to the lateral ends thereof such as to increase the buckling resistance of the annular body under radial load. In fact, the central portion of the supporting element is moved away from the joining elements and may be destroyed during running on the support by the occurrence of a repeated buckling deformation. In the case of supports essentially manufactured with an elastomeric material, such repeated buckling deformation during running initiates and propagates cracking on the side of the walls subjected to extension. On the other hand, in the case of supports essentially manufactured with plastic materials, buckling deformation results in plastic deformation. Such irreversible deformation considerably reduces the stiffness and the loading capacity of the structure, progressively rendering it incapable of fulfilling its function. The ratio between the thickness of the partitions in the central portion thereof and the lateral ends thereof is greater than 1.1 and preferably greater than 1.5. The variation in thickness very substantially increases the buckling resistance of the central portion of the partitions, which means that, for a given radial load, the thickness of the joining elements may be limited and the total weight of the support may be reduced. From one lateral end to the other, these partitions exhibit at least one reversal and, preferably, three reversals in the direction of the curvature thereof. These partitions exhibit, for example, a central portion extending substantially axially between two lateral portions, these lateral portions meeting the joining elements and forming an angle y relative to the circumferential direction ranging from 20 to 40 degrees. According to another embodiment, the partitions exhibit, in the central zone thereof, two portions extending substantially axially and offset circumferentially relative to each other, together with a third joining portion. The mean variation a in orientation between this third joining portion and the two substantially axially oriented portions is preferably greater than 20 degrees. Each joining element may be supported on only one side or on both sides of the supporting element by at least one wall extending substantially axially towards the outside of the annular body. These axial walls are relatively insensitive to buckling because they are integral with the supporting element and relatively short. At a given constant width of the support, these axial walls make it possible to reduce the width of the supporting element and thus to increase the buckling resistance thereof. In a preferred embodiment, each joining element forms with a supporting axial wall and the lateral ends of the two adjacent partitions a three-branched star structure, and the axial width of one axial wall is less than or equal to half the axial width of the two adjacent partitions of the supporting element. The supporting elements according to the invention may also comprise a web which is substantially cylindrical and coaxial with the support, which web is, for example, arranged radially at half height of the supporting element. This web is made from the same material as the rest of the annular body. When arranged at half height, said web allows the height of the partitions to be divided by two, so approximately quadrupling the limit buckling load. In order to facilitate manufacture of the supports according to the invention, the various geometries of the supporting elements are adjusted so as to comprise no undercut portions obstructing axial demoulding of the support. Preferably, a mounted assembly according to the invention for a motor vehicle is of the type comprising a wheel rim, a tyre mounted on said rim and said support according to the invention, said rim comprising on each of the peripheral edges thereof a rim seat intended to receive a bead of said tyre, said rim comprising between the two seats thereof, on the one hand, a bearing surface and, on the other, a mounting groove connecting said bearing surface to an axially internal lip of one of said seats, or first seat. It will be noted that the flat structure which is imparted to said rim by said bearing surface is such that, during flat running, the entire width of the support bears the load, unlike "hollow" type rims. The aforementioned characteristics of the present invention, as well as others, will be better understood on reading the following description of several examples of embodiment of the invention, which are given by way of illustration and not of limitation in comparison with other examples not according to the invention. The above-stated three embodiments relating to examples of architecture of the support according to the invention will moreover be illustrated below by the attached drawings which show: - Fig. 1 is a side view of a safety support according to one embodiment of the invention, - Fig. 2 is an axial section of a mounted assembly according to the invention, in which the support of Fig. 1 is mounted on a wheel rim and is in supporting position against a tyre, - Fig. 3 is a section along line AA in Fig. 1 of a supporting element according to a first embodiment of the invention, - Fig. 4 is a section along line AA in Fig. 1 of a supporting element according to a second embodiment of the invention which comprises partitions connected together by alternate circumferential joining elements, - Fig. 5, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element, the partitions of which are of variable thickness, - Fig. 6, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element, the partitions of which comprise a central connecting portion which is oriented circumferentially, - Fig. 7, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element, the circumferential joining elements of which are of variable length, - Fig. 8, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element, the partitions of which exhibit three reversals of curvature across the width thereof, - Fig. 9, similar to Fig. 4, is a section along line AA in Fig. 1 of an annular body including another embodiment of a supporting element, the partitions of which exhibit three reversals of curvature across the width thereof, - Figs. 10 and 11, similar to Fig. 4, are respectively sections according to line AA in Fig. 1 of annular bodies according to the invention including supporting elements, the partitions of which are of variable thickness and having axial supporting walls, - Fig. 12 is a side view of a support according to said second embodiment of the invention, the annular body of which comprises a central web, and - Fig. 13 is a perspective view illustrating a known support architecture. In these examples, flat running tests were performed on supports according to the invention and "control" supports which differ, on the one hand, with regard to the composition of the rubber from which they are made and, on the other hand, by the selected architecture for these supports. With reference to Figs. 1 and 2, each of the supports 1 tested essentially comprises three parts: - a base 2, of generally annular shape; - a, substantially annular, crown 3, (optionally) having longitudinal grooves 5 on the radially external wall thereof, and - an annular body 4 connecting the base 2 and crown 3. Fig. 2 in particular illustrates the function of a support 1, namely of supporting the tyre tread in the event of severe loss of inflation pressure of the tyre. Each of these tested supports was incorporated into a mounted assembly intended to equip a motor vehicle sold under the name "PEUGEOT 806". The rim used for this mounted assembly was that as is shown in Fig. 2, which has been described above with reference to the preferred mounted assembly of the invention (this rim is also described in detail in French patent specification FR-A-2 720 977). More precisely, the characteristic dimensions (respectively tyre width, tyre diameter, rim diameter) of each mounted assembly which was tested are, in mm: 205 - 650 - 440. The characteristic dimensions (respectively width, internal diameter, height) in mm of each support which was tested are 135 - 440 - 50. For each flat running test (control tests and tests according to the invention), care was taken to ensure that the same relative crushing of the support in the radial direction thereof was obtained (this constant relative crushing being defined as the ratio of deflection to the height of the support). The running conditions for each of the tests were as follows: - load on wheel: 530 kg; - running speed: 100 km/h; - running temperature: between 20°C and 25°C. - running on a motorway type circuit. CONTROL EXAMPLES; 1) Control example 1; A first control support which was incorporated into the above-stated mounted assembly for the purposes of the flat running test consists of a vulcanised rubber composition as defined below: - elastomer: natural rubber 100 phr; - reinforcing filler: "ZEOSIL 1165 MP" silica 54 phr (silica sold by Rhodia exhibiting BET and CTAB surface area values of at least 150 to 160 m2/g); - coupling agent: Si69/carbon black N330 8.5 phr (of which, 4.25 phr Si69 and 4.25 phr carbon black N330); - "6PPD": 2 phr; - ZnO: 4 phr; - stearic acid: 1 phr; - vulcanisation accelerator: "CBS": 3 phr; - sulphur: 4.5 phr; where "6PPD" is N-(l,3-dimethylbutyl)-Nl-phenyl-p-phenylenediamine and "CBS" is N-cyclohexylbenzothiazyl sulphenamide. This first control support is characterised by an Ml0 elasticity modulus of 9 MPa (M10 being the standard abbreviation for a secant elongation modulus obtained at a deformation of approx. 10%, at room temperature and on the third loading cycle, in accordance with Standard ISO 3 7-1977). This support is of a known architecture, which is shown in Fig. 13, in relation to Figs, land 2. The section of Fig. 2 shows a first solid portion 4a of the annular body 4 together with a second portion 4b consisting of recesses (c.f. also Fig. 1) extending axially over substantially more than half the annular body 4 and opening on the outside in a substantially axial direction. These recesses 4b are distributed regularly around the entire circumference of the annular body 4 and they define partitions 6, which provide a direct radial connection between the crown 2 and the base 3 of the support 1. This geometry has the advantage of subjecting the partitions 6 to flexural rather than compressive loads when said partitions are crushed. The recesses 4b and thus the partitions 6 are sufficient in number to ensure regular support during running on the support. More precisely, this first control support 1 which was tested comprises, around its circumference, 38 partitions 6, each of which exhibits a thickness of 18 mm and which are spaced two by two at a distance of 38 mm. Furthermore, the base 2 and crown 3 exhibit a thickness of 7 mm and 8 mm respectively. The annular body of this first control support 1 exhibits a thickness (in the axial direction) of 35 mm. The mass of this first control support is 8 kg. The results of the running test under the above-stated conditions for said mounted assembly comprising this first control support revealed a service life of greater than 200 km. 2) Control example 2: A second control support which was incorporated into the above-stated mounted assembly for the purposes of the flat running test consists of a vulcanised rubber composition which differs from that of the first control support solely in that it comprises a blend of natural rubber (60 phr) and polybutadiene (40 phr); the architecture, dimensions and mass of this support are identical to those of said first control support. This second control support is characterised by substantially identical M10 modulus values relative to said first control support. The results of the running test under the above-stated conditions for this mounted assembly comprising this second control support also revealed a service life of greater than 200km. Testing was also performed on other control supports consisting of control compositions according to said control examples 1 or 2, but exhibiting an architecture as described below with reference to Figs. 3 to 12. The results of the running test under the above-stated conditions revealed a service life in this case of less than 100 km. EXAMPLES OF SUPPORTS ACCORDING TO THE INVENTION; A series of supports according to the invention was tested, all the supports consisting of the same vulcanised rubber composition and respectively exhibiting the architectures illustrated in Figs. 3 to 12. For the sake of clarity in the present description, these tested support architectures will be presented at the end of said description. Each support according to the invention is characterised by the following vulcanised rubber composition of which it consists: - elastomer: natural rubber 100 phr, - reinforcing filler: "ZEOSIL 1165 MP" silica 70 phr; - coupling agent: Si69/carbon black N330 11 phr; (of which, 5.5 phr Si69 and 5.5 phr carbon black N330); - "6PPD": 2 phr; - ZnO: 4 phr; - stearic acid: 1 phr; - vulcanisation accelerator: "CBS": 3 phr; - sulphur: 4.5 phr; Advantageously, each support of the invention has a mass of 5 kg, which is substantially reduced by one third, relative to the mass of 8 kg of each of the control supports. It will consequently be noted that such a support according to the invention exhibits a reduced mass relative to these said "control" supports. Furthermore, the results of the running test under the above-stated conditions for mounted assemblies respectively comprising supports according to the invention also revealed a service life of greater than 200 km Additionally, each support according to the invention is characterised by an M10 modulus of 16 MPa, a modulus higher than that of said "control" supports. It will be noted that the reinforcing white filler, such as silica, which is used in the rubber composition of each support according to the invention imparts to this composition, on the one hand, improved uncured processing characteristics and, on the other hand, likewise improved cured properties, such as cohesion, in addition to the above-mentioned rigidity. Architectures tested in each case for the supports according to the invention; - A first preferred design of architecture for the support according to the invention is illustrated in Fig. 3. As has been stated above in general terms, with reference to Figs. 1 and 2, a safety support 1 according to Fig. 3 is of the type comprising said base 1, said crown 3 and said annular body 4. Fig. 3 shows a circumferentially continuous supporting element 7 of this preferred support 1, said supporting element comprising a plurality of partitions 6 extending axially on each side of said circumferential median plane P of the support 1 and being distributed around the circumference of said support 1. It may be seen in Fig. 3 that this supporting element 7 comprises, on one of said sides of the support 1, joining elements 8 extending substantially circumferentially. Each joining element 8 connects the respective ends 6a of two adjacent partitions 6 which are arranged on said side of the support 1, and said joining elements 8 are arranged alternately in succession on each side of said partitions 6. More precisely, the joining elements 8 are mutually supported between two adjacent partitions 6 by a rib 8a extending from said crown 3 to said base 2 of the support 1, such that said joining elements 8 form a continuous joining wall 9 in the form of a gusset all along said side of said support 1. More precisely, said joining wall 9, comprises a plurality of cells 9a, each delimited by two adjacent ribs 8a. The bottom of each cell 9a substantially exhibits a dihedral shape, the ridge of which is formed by one end 6a of the partition 6 and the faces of which are respectively formed by said alternate joining elements 8. In this preferred tested example of architecture, there are 40 partitions 6 of the support 1 around the circumference of said support 1, each partition exhibits a thickness of 8 mm and they are 40 mm apart. As has been stated above, each support 1 tested exhibits a width of 135 mm, a diameter of 440 mm and a height of 50 mm. Furthermore, the base 2 and crown 3 of said support 1 exhibit a thickness of 6 mm and 7 mm respectively. Moreover, the distance in the axial direction between a plane P, which is axially median for said joining elements 8, and the respective free ends of said ribs 8a, is 20 mm in this preferred example. - A second design of architecture for the support 1 according to the invention is illustrated in Fig. 4, with Figs. 5 to 12 illustrating variants of this second design (the structural elements analogous to those of Fig. 4 are hereinafter identified by reference numerals incremented by 10 for each Fig., starting from Fig. 5). As in the stated first design, the supports 1 relating to these Figs. 4 to 12 are all of the type comprising said base 2, said crown 3 and an annular body 10. * Fig. 4 shows such an annular body 10. This annular body consists of a circumferentially continuous supporting element 11 which comprises a set of partitions 12 connected two by two by joining elements 13. The partitions 12 extend laterally on each side of the circumferential median plane P of the support 1 and they are regularly distributed around the circumference of said support 1. They have an angle of inclination A, relative to the circumferential direction, which approaches 90 degrees. The thickness H thereof is constant. Furthermore, two adjacent partitions 12 have an opposing angle of inclination relative to the axial direction. These joining elements 13 have a thickness e, they are oriented circumferentially and each connects the respective ends of two adjacent partitions 12 which are arranged on the same side of the support 1 (these two ends are the ones closest to each other). The joining elements 13 are thus arranged alternately in succession on each side of the partitions 12. It will be noted that, in order to facilitate manufacture of the support 1 with axial demoulding, the supporting element 11 comprises no undercut elements. * Fig. 5 shows a variant embodiment of a supporting element 21, with reference to the supporting element 11 of Fig. 4. The partitions 22 of this supporting element 21 have a thickness H in the central portion thereof which is greater than the thickness h thereof at the lateral ends of the partitions. In this example, H is approximately twice the size of h. This variation in thickness imparts very good buckling resistance to the central portions of the partitions 22. The lateral ends are connected to the joining elements 23 in continuous manner, which imparts good buckling resistance thereto. It will be noted that a variation in thickness of as little as 10% may have appreciable effects for the purpose of postponing the onset of overload buckling. * Fig. 6 shows another variant embodiment of a supporting element 31. As previously, this supporting element comprises partitions 32 which are connected by joining elements 33. The partitions 32 comprise two lateral portions 34 of the same angle of inclination A relative to the circumferential direction, which are offset circumferentially and are connected in the central portion of said supporting element 31 by a third portion 35 oriented substantially circumferentially. The mean variation a in orientation between lateral portions 34 and the central portion 35 is of the order of 80 degrees in this case. Since the portions 35 are oriented circumferentially, the angles a and A are equal. This presence of this third central portion 35, which has a mean orientation differing greatly from that of the two lateral portions, increases the buckling resistance of the central portion of the partitions 22. It will be noted that, in order to be effective, this variation a must be greater than 20 degrees. In this embodiment, the partitions 32 comprise, from one lateral end to the other, one reversal in the direction of the curvature thereof. * Fig. 7 shows another variant embodiment of a supporting element 41. In this case, the joining elements 43 which are arranged on one side of the supporting element 41 have a circumferential length which is less than that of the joining elements 44, which are arranged on the other side of the supporting element 41. It will be noted that the substantially doubled length of the joining elements 44 increases the compressive stiffness of the supporting element 41 on this side of the support 1. This latter side should be arranged towards the interior side of the vehicle, where the loads borne by the support 1 while in operation are the greatest. * Fig. 8 shows another variant embodiment of a supporting element 51. In this case, the joining elements 53 are virtually reduced to the contact surface between the two lateral ends 54 as an arc of a circle of the partitions 52. The partitions 52 also comprise a central connecting portion 55. It will be noted that the variation a in mean orientation between the two lateral portions 56 and the central portion 55 is greater than 90 degrees and is of the order of 110 degrees, which increases the mean supporting density of the supporting element 51 in the central portion thereof. From one lateral end to the other, these partitions 52 comprise three reversals in the direction of the curvature thereof. * Fig. 9 shows another variant embodiment of a supporting element 61, a variant similar to that of Fig. 8 with the following modifications. The partitions 62 comprise rectilinear segments and exhibit three reversals in the direction of the curvature thereof. The partitions comprise two axially oriented lateral portions 64, which are connected, on the one hand, by a central portion 65 and, on the other hand, to the joining elements 63 by lateral ends 66 of a mean orientation y approaching 30 degrees, relative to the circumferential direction. The mean variation a in orientation between the two axially oriented portions 64 of the partitions 62 and the central joining portion 65 is of the order of 40 degrees. These joining elements 63 may in this case be defined as elements of a substantially triangular cross-section which are arranged between two adjacent lateral ends 66. On both sides of the supporting element 61, the annular body 60 comprises a series of substantially axially oriented walls 67 which extends each joining element 63 towards the outside of the support 1. As may be seen in Fig. 9, the meeting of each joining element 63, of the said adjacent lateral ends 66 and of said axial wall 67 accordingly forms a three-branched star, which is highly resistant to buckling. * Fig. 10 shows another variant embodiment of a supporting element 70 and, consequently, of a supporting element 71. This latter element comprises partitions 72 with axially oriented central portions 74 which are extended on each side by a lateral end 75, which exhibits an orientation y approaching 30 degrees relative to the circumferential direction. On one side of the annular body 70, the joining elements 73 are reduced to the contact surface between the two adjacent lateral ends 75. On the other side, the annular body 70 comprises lateral walls 76 which support the joining elements 77 on this side, said joining elements being of a substantially triangular shape. It will be noted that on this latter side, the compressive stiffness of the supporting element is greater. The length of the lateral walls 76 is in particular less than half the length of the central portions 74 of the partitions 72, so that they are not liable to buckle. The side of the supporting element 71 having the highest radial compressive stiffness should preferably be arranged on the interior side of the vehicle. It has, in fact, been observed that the loads are highest on this interior side of the vehicle. The partitions 72 have a thickness H in the central portion 74 thereof which is greater than the thickness h of the lateral portions 75 thereof, so as to increase the buckling resistance of this central portion 74. * Fig. 11 shows another variant embodiment of a supporting element 80, a variant very similar to said annular body 70 of Fig. 10. This annular body 80 comprises axial lateral walls 86 and 87 which support the supporting element 81 on both sides, said supporting element also being structurally very similar to said supporting element 71. For a given width of the annular body 80, these lateral walls 86 and 87 exhibit the advantage of reducing the axial width of the partitions 82 of the continuous supporting element 81 and thus of improving the buckling resistance of the overall structure. The axial lengths of said walls 86 and 87 may differ, as illustrated in Fig. 11. * Fig. 12 shows an axial view of a support 1 including a supporting element 91 as described in Fig. 11, but additionally comprising a circumferential web 94 which is arranged at half height of the annular body 90. This circumferential web 94, of cylindrical shape, exhibits the advantage of bringing about a very substantial increase, of the order of a factor of four, of the limit buckling load of the structure of the support 1. Each of the supports 1 described with reference to Figs. 4 to 12 exhibits the following dimensional characteristics. There are 40 partitions 12, ..., 92 around the circumference of each support 1, each partition exhibits a thickness of 8 mm and they are 40 mm apart. As has been stated above, each support 1 tested exhibits a width of 135 mm, a diameter of 440 mm and a height of 50 mm. Furthermore, the base 2 and crown 3 of said support 1 exhibit a thickness of 6 mm and 7 mm respectively. All the supporting elements 7, 11, ...,91 and the annular bodies 4, 10,..., 90 presented above may be manufactured by moulding techniques. In order to facilitate axial demoulding, they preferably comprise no undercut portions. It will be noted that it would also be possible to use, as a support architecture according to the invention, a support consisting of two or more rings connected together in the axial direction of said support, the overall structure thereof remaining unchanged. It could, for example, be possible to provide for such a support a first ring of a substantially rectangular axial section, and one or more annular elements comprising a plurality of recesses and extending substantially axially across the entire width thereof and distributed substantially regularly around the circumference thereof. Such a ring-type support is easier to introduce into a tyre, due to the lower flexural rigidity of the various annular elements thereof. WE CLAIM : 1) A safety support (1) intended to be mounted on a wheel rim inside a tyre, wherein said support (1) consists of a vulcanised rubber composition comprising (phr means parts by weight per 100 parts of diene elastomer(s)): natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr, more than 60 phr of a reinforcing white filler, and from 3 to 8 phr of sulphur. 2) A safety support as claimed in claim 1, wherein said reinforcing white filler consists of silica in a quantity ranging from 60 to 80 phr. 3) A safety support as claimed in claim 1 or 2, wherein said silica exhibits BET or CTAB surface area values which are both in a range from 50 m2/g to 200 m2/g. 4) A safety support as claimed in claim 3, wherein said silica exhibits BET or CTAB surface area values which are both in a range from 110 m2/g to 200 m2/g. 5) A safety support as claimed in one of the preceding claims, wherein said composition comprises a reinforcing white filler/elastomer bonding agent which is of the poly sulphurised alkoxysilane type. 6) A safety support as claimed in one of the preceding claims, wherein said composition also has a homopolymer obtained by polymerisation of a conjugated diene monomer having 4 to 12 carbon atoms, or a copolymer obtained by copolymerisation of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms, in a quantity of less than or equal to 40 phr. 7) A safety support as claimed in claim 6, wherein said composition has a blend of natural rubber and polybutadiene. 8) A safety support as claimed in one of claims 1 to 5, wherein said composition has a single diene elastomer consisting of natural rubber or synthetic polyisoprene. 9) A safety support as claimed in one of the preceding claims, wherein said composition exhibits an M10 elasticity modulus at 10% deformation which is greater than 10 MPa. 10) A safety support substantially as herein described with reference to the accompanying drawings.

Full Text

The present invention relates to a safety support (1) intended to be mounted on a wheel rim inside a tyre, wherein said support (1) consists of a vulcanised rubber composition comprising (phr means parts by weight per 100 parts of diene elastomer(s)):
natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr,
more than 60 phr of a reinforcing white filler, and
from 3 to 8 phr of sulphur.The present invention relates to a rubber composition usable in the vulcanised state as a safety support intended to be mounted on a wheel rim within a tyre, to such a support capable of supporting a tread of said tyre in the event of a drop in inflation pressure and to a mounted assembly comprising this support.
In known manner, safety supports for vehicle tyres are intended to be mounted on a rim within the tyre for the purpose of being capable of supporting the tread of this tyre in the event of a loss of inflation pressure. These supports in particular comprise a base which is intended to conform to the rim and a crown which is intended to come into contact with the tread in the above-stated event and which leaves a clearance relative thereto at nominal pressure.
Japanese patent specification JP-A-3782601 proposes such a support, the base and crown of which are substantially cylindrical and which moreover comprises an annular body connecting said base and said crown.
This annular body comprises a supporting element which is continuous circumferentially and which comprises:
• a plurality of partitions extending axially on each side of said circumferential
median plane and distributed around the circumference of said support, and
• joining elements extending substantially circumferentially, each joining element
connecting the respective ends of two adjacent partitions which are arranged on the same
side of the support, said joining elements being arranged alternately in succession on each
side of said partitions;
in which the partitions and joining elements are substantially rectilinear and the difference between the maximum and minimum values of the area of an axial section of the support element as a function of the azimuth, relative to the sum of these same areas, is preferably less than 0.3. As a consequence, as a function of the azimuth, the area of an axial section of the support element varies at most by a factor of two in order to ensure good uniformity of loading capacity and to limit vibration when running on the support.
This support is essentially produced using a hard polymeric material and the whole supporting element is designed to withstand compressive loads.
Such supports may be produced in conventional manner, for example by injection moulding.
The object of the present invention is to provide & rubber composition, usable in the vulcanised state as a safety support intended to be mounted on a wheel rim inside a tyre, which composition is such that, at a comparable flat running service life, the weight reduction performance for said support is further improved.
To this end, a rubber composition according to the invention is such that it comprises
(phr: parts by weight per 100 parts of diene elastomer(s)):
- natural rubber or synthetic polyisoprene in a quantity of greater than or equal to
60 phr,
- more than 60 phr of a reinforcing white filler, and
- from 3 to 8 phr of sulphur.
It will be noted that the invention relates to rubber compositions in both the non-vulcanised state and the vulcanised state.
With regard to said elastomer(s), a diene elastomer is taken to mean an elastomer obtained at least in part (i.e. a homopolymer or copolymer) from diene monomers (conjugated or unconjugated monomers bearing two double carbon-carbon bonds).
Preferably, it will be noted that said elastomers are constituted by at last one essentially unsaturated diene elastomer.
An essentially unsaturated diene elastomer is taken to mean a diene elastomer which is obtained at least in part from conjugated diene monomers having a content of moieties or units of diene origin (conjugated dienes) which is greater than 15% (mol%) and, for example:
a) any homopolymer obtained by polymerisation of a conjugated diene monomer, such as 1,3-butadiene, 2-methyl-1,3-butadiene (or isoprene), 2,3-di(Cl to C5 alkyl)-1,3-butadiene,
such as for example 2,3-dimethyl-l,3-butadiene, 2,3-diethyl-l,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene.
b) any copolymer obtained by copolymerisation of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds, such as styrene, ortho-, para- or meta-methylstyrene. Butadiene-styrene copolymers, or butadiene-isoprene copolymers may be mentioned by way of example.
According to one embodiment of the invention, said composition also comprises a homopolymer obtained by polymerisation of a conjugated diene monomer having 4 to 12 carbon atoms, or a copolymer obtained by copolymerisation of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms, in a quantity of less than or equal to 40 phr.
Said composition accordingly comprises, for example, a blend of natural rubber and polybutadiene.
According to another embodiment of the invention, said composition comprises a single diene elastomer entirely consisting of natural rubber or synthetic polyisoprene.
A reinforcing white filler is taken to mean a white filler which is capable, on its own, without any intermediate means other than a white filler/elastomer bonding agent, of reinforcing a rubber composition intended for the manufacture of tyres, in other words which is capable of replacing the reinforcement action of a conventional filler of tyre-grade carbon black.
Such a reinforcing white filler may, for example, consist of silica and is advantageously present in said composition in a quantity between 60 and 80 phr and, still more preferably, in a quantity between 65 and 75 phr.
Suitable silicas which may be used are any precipitated or pyrogenic silicas known to the person skilled in the art, the BET or CTAB surface area values of which are both within a range from 50 m2/g to 200 m2/g, with highly dispersible precipitated silicas being preferred.
"Highly dispersible silica" is understood to mean any silica having a very substantial ability to disagglomerate and to disperse in an elastomeric matrix, which can be observed in known manner by electron or optical microscopy on thin sections. Non-limitative examples of
such highly dispersible silicas usable for the invention which may, for example, be mentioned are silicas BV 3370 and BV 3380 from Degussa, silicas Zeosil 1165 MP and 1115 MP from Rhodia, silica BXR 160 from PPG or silica Zeopol 8745 M from Huber.
Preferably, a silica is used, the BET or CTAB surface area values of which are both in the range between 110 and 200 m2/g and, still more preferably, between 140 and 195 m2/g.
The physical state of the silica is immaterial, whether it be in the form of a powder, microbeads, granules, balls.
Silica is, of course, also taken to mean blends of different silicas. The silica may be used alone or in the presence of other white fillers. The CTAB specific surface area value is determined in accordance with the method of Standard NFT 45007 of November 1987. The BET specific surface area value is determined in accordance with the method of BRUNAUER, EMMETT and TELLER, which is described in "The Journal of the American Chemical Society, vol. 60, p. 309 (1938)" and corresponds to Standard NFT 45007 of November 1987.
The following are non-limiting examples of reinforcing white fillers which may also be used:
- aluminas (of the formula Al2O3), such as the high dispersibility aluminas which are
described in European Patent Specification EP-A-810 258 or alternatively
- aluminium hydroxides, such as those described in international patent specification
WO-A-99/28376.
It will be noted that the composition of the invention could comprise carbon black in addition to said reinforcing white filler, for example in the form of a carbon/silica blend.
The rubber composition according to the invention moreover conventionally comprises a reinforcing white filler/elastomer bonding agent (also known as a coupling agent), the purpose of which is to provide an adequate chemical and/or physical bond (coupling) between said white filler and said elastomer(s) while facilitating dispersion of this white filler within the latter.
Such a bonding agent, which is at least bifunctional, has, for example, the simplified general formula "Y-T-X", in which:
-Y represents a functional group ("Y" function) which is capable of bonding physically and/or chemically with the white filler, such a bond being able to be established, for example,
between a silicon atom of the coupling agent and the hydroxyl (OH) surface groups of the filler (for example, surface silanols in the case of silica),
-X represents a functional group ("X" function) which is capable of bonding physically and/or chemically with the elastomer, for example by means of a sulphur atom;
-T represents a hydrocarbon group making it possible to link Y and X.
These bonding agents must in particular not be confused with simple agents for coating the filler in question which, in known manner, may comprise the Y function which is active with respect to the filler but are devoid of the X function which is active with respect to the elastomer.
Such bonding agents, of variable effectiveness, have been described in a very large number of documents and are well-known to the person skilled in the art. In fact, it is possible to use any bonding agent which is known to or likely to ensure, in the diene rubber compositions usable for the manufacture of tyres, effective bonding between the silica and diene elastomer, such as, for example, organosilanes, in particular polysulphurised alkoxysilanes or mercaptosilanes.
In particular polysulphurised alkoxysilanes are used, such as are described, for example, in patent specifications US-A-3 842 111, US-A-3 873 489, US-A-3 978 103, US-A-3 997 581, US-A-4 002 594 or, more recently, US-A-5 580 919, US-A-5 583 245, US-A-5 663 396, US-A-5 684 171, US-A-5 684 172 and US-A-5 696 197, which describe such known compounds in detail.
Particularly suitable for the composition of the invention, without the definition below being limitative, are so-called "symmetrical" polysulphurised alkoxysilanes which satisfy the following general formula (I):
(I) Z-A-Sn-A-Z, in which:
- n is an integer from 2 to 8 (preferably from 2 to 5);
- A is a divalent hydrocarbon radical (preferably C1-C18 alkylene groups or C6-C12
arylene groups, more particularly C1-C180 alkylenes, in particular C2-C4 alkylenes, in particular
propylene);
- Z corresponds to one of the formulae below:

(Formula Removed)
in which:
- the radicals R1, which may or may not be substituted, and may be identical or
different, represent a C1-C18 alkyl group, a C5-C18 cycloalkyl group, or a C6-C18 aryl group
(preferably C1-C6 alkyl groups, cyclohexyl or phenyl, in particular C1-C4 alkyl groups, more
particularly methyl and/or ethyl);
- the radicals R2, which may or may not be substituted, and may be identical or
different, represent a C1-C18 alkoxyl group or C5-C18 cycloalkoxyl group (preferably C1-C8
alkoxyl groups or C5-C8 cycloalkoxyl groups, more particularly methoxyl and/or ethoxyl).
In the case of a mixture of polysulphurised alkoxysilanes corresponding to the formula (I) above, in particular conventional commercially available mixtures, it will be understood that the mean value of "n" is a fractional number, preferably varying between 2 and 5.
Polysulphurised alkoxysilanes which may more particularly be mentioned are polysulphides (in particular tetrasulphides) of bis(alkoxyl(C1-C4)silylpropyl), in particular of bis(trialkoxyl(C1-C4)silylpropyl), in particular polysulphides of bis(3-trimethoxysilylpropyl) or of bis(3-triethoxysilylpropyl). Among these compounds, bis(3-triethoxysilylpropyl) tetrasulphide, abbreviated TESPT, of the formula [(C2H5O)3Si(CH2)3S2]2, is preferably used, which is sold, for example by Degussa under the name Si69 (or X50S when supported at a content of 50 wt.% on carbon black) or alternatively by Witco under the name Silquest A1289.
The person skilled in the art will be able to adjust the content of coupling agent in the compositions of the invention, according to the intended application, the elastomer(s) used and the quantity of reinforcing white filler used.
In the rubber compositions according to the invention, the content by weight of coupling agent may be within a range from 2 to 15% relative to the mass of reinforcing white filler, and, preferably, within a range from 5 to 12%.
With regard to the sulphur content in the composition according to the invention, it will be noted that it may preferably vary from 4 to 6 phr.
The rubber compositions according to the invention contain, apart from said elastomer(s), said reinforcing filler, sulphur and one or more reinforcing white filler/elastomer bonding agent(s), all or part of the other constituents and additives usually used in rubber mixtures, such as plasticisers, pigments, antioxidants, vulcanisation accelerators, extender oils, one or more agents for coating the reinforcing white filler, such as alkoxysilanes, polyols, amines etc..
According to another feature of the invention, said rubber composition exhibits an M10 elasticity modulus at 10% deformation which is greater than 10 MPa, advantageously greater than 12 MPa and is preferably between 13 and 20 MPa.
The vulcanised rubber composition according to the invention is prepared using three successive preparation stages in accordance with a procedure familiar to person skilled in the art:
- a first thermomechanical working or kneading stage (sometimes known as the "non
productive" stage) at elevated temperature, up to a maximum temperature between 130°C and
200°C, preferably between 145°C and 185°C, during which all the necessary constituents
including the coupling system according to the invention, any optional filler coating agents or
complementary processing agents and various other additives, with the exception of the
vulcanisation system, are introduced, for example, into an appropriate mixer, such as a
conventional internal mixer;
- a second mechanical working stage (sometimes known as the "productive" stage) at
lower temperature, typically below 120°C, for example between 60°C and 100°C, the finishing
phase during which the crosslinking or vulcanisation system is incorporated; such stages are
described, for example, in patent specification EP-A-0 501 227, and
- a third vulcanisation stage of the mixture obtained on completion of the second stage.
A safety support according to the invention is such that it consists of said rubber composition of the invention.
This support according to the invention is, for example, of the type comprising:
- a substantially cylindrical base, intended to conform to the rim,
- a substantially cylindrical crown intended to come into contact with the tyre tread in
the event of a drop in pressure and to leave a clearance relative to said tread at nominal
pressure, and
- an annular body connecting said base and said crown together, said body comprising
a circumferentially continuous supporting element with a circumferential median plane, said
supporting element comprising a plurality of partitions extending axially on each side of said
circumferential median plane and distributed around the circumference of said support.
According to a first embodiment of this example of a support according to the invention, said annular body also comprises, on one of said sides of the support, joining elements extending substantially circumferentially, each joining element connecting the respective ends of two adjacent partitions which are arranged on the said side of the support, said joining elements being arranged alternately in succession on each side of said partitions.
In this first embodiment, said joining elements are mutually supported between two adjacent partitions by a rib extending from said crown to said base of the support such that said joining elements form a continuous joining wall in the form of a gusset all along said side of said support.
More precisely, said joining wall comprises a plurality of cells, each of which is delimited by two adjacent ribs, the bottom of each cell substantially exhibiting a dihedral shape, the ridge of which is formed by one of said partitions and the faces of which are respectively formed by said alternate joining elements.
According to a second embodiment of this example of a support according to the invention, said annular body also comprises, on both sides of the support, joining elements extending substantially circumferentially, each joining element connecting the respective ends of two adjacent partitions which are arranged on the same side of the support, said joining elements being arranged alternately in succession on each side of said partitions.
In this second embodiment, said partitions are modified in the central portion thereof relative to the lateral ends thereof such as to increase the buckling resistance of the annular body under radial load.
In fact, the central portion of the supporting element is moved away from the joining elements and may be destroyed during running on the support by the occurrence of a repeated buckling deformation. In the case of supports essentially manufactured with an elastomeric material, such repeated buckling deformation during running initiates and propagates cracking on the side of the walls subjected to extension. On the other hand, in the case of supports essentially manufactured with plastic materials, buckling deformation results in plastic deformation. Such irreversible deformation considerably reduces the stiffness and the loading capacity of the structure, progressively rendering it incapable of fulfilling its function.
The ratio between the thickness of the partitions in the central portion thereof and the lateral ends thereof is greater than 1.1 and preferably greater than 1.5. The variation in thickness very substantially increases the buckling resistance of the central portion of the partitions, which means that, for a given radial load, the thickness of the joining elements may be limited and the total weight of the support may be reduced.
From one lateral end to the other, these partitions exhibit at least one reversal and, preferably, three reversals in the direction of the curvature thereof.
These partitions exhibit, for example, a central portion extending substantially axially between two lateral portions, these lateral portions meeting the joining elements and forming an angle y relative to the circumferential direction ranging from 20 to 40 degrees.
According to another embodiment, the partitions exhibit, in the central zone thereof, two portions extending substantially axially and offset circumferentially relative to each other, together with a third joining portion. The mean variation a in orientation between this third joining portion and the two substantially axially oriented portions is preferably greater than 20 degrees.
Each joining element may be supported on only one side or on both sides of the supporting element by at least one wall extending substantially axially towards the outside of the annular body.
These axial walls are relatively insensitive to buckling because they are integral with the supporting element and relatively short. At a given constant width of the support, these axial walls make it possible to reduce the width of the supporting element and thus to increase the buckling resistance thereof.
In a preferred embodiment, each joining element forms with a supporting axial wall and the lateral ends of the two adjacent partitions a three-branched star structure, and the axial width of one axial wall is less than or equal to half the axial width of the two adjacent partitions of the supporting element.
The supporting elements according to the invention may also comprise a web which is substantially cylindrical and coaxial with the support, which web is, for example, arranged radially at half height of the supporting element.
This web is made from the same material as the rest of the annular body. When arranged at half height, said web allows the height of the partitions to be divided by two, so approximately quadrupling the limit buckling load.
In order to facilitate manufacture of the supports according to the invention, the various geometries of the supporting elements are adjusted so as to comprise no undercut portions obstructing axial demoulding of the support.
Preferably, a mounted assembly according to the invention for a motor vehicle is of the type comprising a wheel rim, a tyre mounted on said rim and said support according to the invention, said rim comprising on each of the peripheral edges thereof a rim seat intended to receive a bead of said tyre, said rim comprising between the two seats thereof, on the one hand, a bearing surface and, on the other, a mounting groove connecting said bearing surface to an axially internal lip of one of said seats, or first seat.
It will be noted that the flat structure which is imparted to said rim by said bearing surface is such that, during flat running, the entire width of the support bears the load, unlike "hollow" type rims.
The aforementioned characteristics of the present invention, as well as others, will be better understood on reading the following description of several examples of embodiment of
the invention, which are given by way of illustration and not of limitation in comparison with other examples not according to the invention.
The above-stated three embodiments relating to examples of architecture of the support according to the invention will moreover be illustrated below by the attached drawings which show:
- Fig. 1 is a side view of a safety support according to one embodiment of the
invention,
- Fig. 2 is an axial section of a mounted assembly according to the invention, in which
the support of Fig. 1 is mounted on a wheel rim and is in supporting position against a tyre,
- Fig. 3 is a section along line AA in Fig. 1 of a supporting element according to a
first embodiment of the invention,
- Fig. 4 is a section along line AA in Fig. 1 of a supporting element according to a
second embodiment of the invention which comprises partitions connected together by
alternate circumferential joining elements,
- Fig. 5, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element,
the partitions of which are of variable thickness,
- Fig. 6, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element,
the partitions of which comprise a central connecting portion which is oriented
circumferentially,
- Fig. 7, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element,
the circumferential joining elements of which are of variable length,
- Fig. 8, similar to Fig. 4, is a section along line AA in Fig. 1 of a supporting element,
the partitions of which exhibit three reversals of curvature across the width thereof,
- Fig. 9, similar to Fig. 4, is a section along line AA in Fig. 1 of an annular body
including another embodiment of a supporting element, the partitions of which exhibit three
reversals of curvature across the width thereof,
- Figs. 10 and 11, similar to Fig. 4, are respectively sections according to line AA in
Fig. 1 of annular bodies according to the invention including supporting elements, the
partitions of which are of variable thickness and having axial supporting walls,
- Fig. 12 is a side view of a support according to said second embodiment of the
invention, the annular body of which comprises a central web, and
- Fig. 13 is a perspective view illustrating a known support architecture.
In these examples, flat running tests were performed on supports according to the invention and "control" supports which differ, on the one hand, with regard to the composition of the rubber from which they are made and, on the other hand, by the selected architecture for these supports.
With reference to Figs. 1 and 2, each of the supports 1 tested essentially comprises three parts:
- a base 2, of generally annular shape;
- a, substantially annular, crown 3, (optionally) having longitudinal grooves 5 on the
radially external wall thereof, and
- an annular body 4 connecting the base 2 and crown 3.
Fig. 2 in particular illustrates the function of a support 1, namely of supporting the tyre tread in the event of severe loss of inflation pressure of the tyre.
Each of these tested supports was incorporated into a mounted assembly intended to equip a motor vehicle sold under the name "PEUGEOT 806".
The rim used for this mounted assembly was that as is shown in Fig. 2, which has been described above with reference to the preferred mounted assembly of the invention (this rim is also described in detail in French patent specification FR-A-2 720 977).
More precisely, the characteristic dimensions (respectively tyre width, tyre diameter, rim diameter) of each mounted assembly which was tested are, in mm:
205 - 650 - 440.
The characteristic dimensions (respectively width, internal diameter, height) in mm of each support which was tested are 135 - 440 - 50.
For each flat running test (control tests and tests according to the invention), care was taken to ensure that the same relative crushing of the support in the radial direction thereof was obtained (this constant relative crushing being defined as the ratio of deflection to the height of the support).
The running conditions for each of the tests were as follows:
- load on wheel: 530 kg;
- running speed: 100 km/h;
- running temperature: between 20°C and 25°C.
- running on a motorway type circuit.
CONTROL EXAMPLES; 1) Control example 1;
A first control support which was incorporated into the above-stated mounted assembly for the purposes of the flat running test consists of a vulcanised rubber composition as defined below:
- elastomer: natural rubber 100 phr;
- reinforcing filler: "ZEOSIL 1165 MP" silica 54 phr
(silica sold by Rhodia exhibiting BET and CTAB surface area values of at least 150 to
160 m2/g);
- coupling agent: Si69/carbon black N330 8.5 phr
(of which, 4.25 phr Si69 and 4.25 phr carbon black N330);
- "6PPD": 2 phr;
- ZnO: 4 phr;
- stearic acid: 1 phr;
- vulcanisation accelerator: "CBS": 3 phr;
- sulphur: 4.5 phr;
where "6PPD" is N-(l,3-dimethylbutyl)-Nl-phenyl-p-phenylenediamine and "CBS" is N-cyclohexylbenzothiazyl sulphenamide.
This first control support is characterised by an Ml0 elasticity modulus of 9 MPa (M10 being the standard abbreviation for a secant elongation modulus obtained at a deformation of approx. 10%, at room temperature and on the third loading cycle, in accordance with Standard ISO 3 7-1977).
This support is of a known architecture, which is shown in Fig. 13, in relation to Figs, land 2.
The section of Fig. 2 shows a first solid portion 4a of the annular body 4 together with a second portion 4b consisting of recesses (c.f. also Fig. 1) extending axially over substantially
more than half the annular body 4 and opening on the outside in a substantially axial direction. These recesses 4b are distributed regularly around the entire circumference of the annular body 4 and they define partitions 6, which provide a direct radial connection between the crown 2 and the base 3 of the support 1.
This geometry has the advantage of subjecting the partitions 6 to flexural rather than compressive loads when said partitions are crushed. The recesses 4b and thus the partitions 6 are sufficient in number to ensure regular support during running on the support.
More precisely, this first control support 1 which was tested comprises, around its circumference, 38 partitions 6, each of which exhibits a thickness of 18 mm and which are spaced two by two at a distance of 38 mm.
Furthermore, the base 2 and crown 3 exhibit a thickness of 7 mm and 8 mm respectively. The annular body of this first control support 1 exhibits a thickness (in the axial direction) of 35 mm.
The mass of this first control support is 8 kg.
The results of the running test under the above-stated conditions for said mounted assembly comprising this first control support revealed a service life of greater than 200 km.
2) Control example 2:
A second control support which was incorporated into the above-stated mounted assembly for the purposes of the flat running test consists of a vulcanised rubber composition which differs from that of the first control support solely in that it comprises a blend of natural rubber (60 phr) and polybutadiene (40 phr); the architecture, dimensions and mass of this support are identical to those of said first control support.
This second control support is characterised by substantially identical M10 modulus values relative to said first control support.
The results of the running test under the above-stated conditions for this mounted assembly comprising this second control support also revealed a service life of greater than 200km.
Testing was also performed on other control supports consisting of control compositions according to said control examples 1 or 2, but exhibiting an architecture as
described below with reference to Figs. 3 to 12. The results of the running test under the above-stated conditions revealed a service life in this case of less than 100 km.
EXAMPLES OF SUPPORTS ACCORDING TO THE INVENTION;
A series of supports according to the invention was tested, all the supports consisting of the same vulcanised rubber composition and respectively exhibiting the architectures illustrated in Figs. 3 to 12.
For the sake of clarity in the present description, these tested support architectures will be presented at the end of said description.
Each support according to the invention is characterised by the following vulcanised rubber composition of which it consists:
- elastomer: natural rubber 100 phr,
- reinforcing filler: "ZEOSIL 1165 MP" silica 70 phr;
- coupling agent: Si69/carbon black N330 11 phr;
(of which, 5.5 phr Si69 and 5.5 phr carbon black N330);
- "6PPD": 2 phr;
- ZnO: 4 phr;
- stearic acid: 1 phr;
- vulcanisation accelerator: "CBS": 3 phr;
- sulphur: 4.5 phr;
Advantageously, each support of the invention has a mass of 5 kg, which is substantially reduced by one third, relative to the mass of 8 kg of each of the control supports. It will consequently be noted that such a support according to the invention exhibits a reduced mass relative to these said "control" supports.
Furthermore, the results of the running test under the above-stated conditions for mounted assemblies respectively comprising supports according to the invention also revealed a service life of greater than 200 km
Additionally, each support according to the invention is characterised by an M10 modulus of 16 MPa, a modulus higher than that of said "control" supports.
It will be noted that the reinforcing white filler, such as silica, which is used in the rubber composition of each support according to the invention imparts to this composition, on the one hand, improved uncured processing characteristics and, on the other hand, likewise improved cured properties, such as cohesion, in addition to the above-mentioned rigidity.
Architectures tested in each case for the supports according to the invention;
- A first preferred design of architecture for the support according to the invention is illustrated in Fig. 3.
As has been stated above in general terms, with reference to Figs. 1 and 2, a safety support 1 according to Fig. 3 is of the type comprising said base 1, said crown 3 and said annular body 4.
Fig. 3 shows a circumferentially continuous supporting element 7 of this preferred support 1, said supporting element comprising a plurality of partitions 6 extending axially on each side of said circumferential median plane P of the support 1 and being distributed around the circumference of said support 1.
It may be seen in Fig. 3 that this supporting element 7 comprises, on one of said sides of the support 1, joining elements 8 extending substantially circumferentially. Each joining element 8 connects the respective ends 6a of two adjacent partitions 6 which are arranged on said side of the support 1, and said joining elements 8 are arranged alternately in succession on each side of said partitions 6.
More precisely, the joining elements 8 are mutually supported between two adjacent partitions 6 by a rib 8a extending from said crown 3 to said base 2 of the support 1, such that said joining elements 8 form a continuous joining wall 9 in the form of a gusset all along said side of said support 1.
More precisely, said joining wall 9, comprises a plurality of cells 9a, each delimited by two adjacent ribs 8a. The bottom of each cell 9a substantially exhibits a dihedral shape, the
ridge of which is formed by one end 6a of the partition 6 and the faces of which are respectively formed by said alternate joining elements 8.
In this preferred tested example of architecture, there are 40 partitions 6 of the support 1 around the circumference of said support 1, each partition exhibits a thickness of 8 mm and they are 40 mm apart. As has been stated above, each support 1 tested exhibits a width of 135 mm, a diameter of 440 mm and a height of 50 mm.
Furthermore, the base 2 and crown 3 of said support 1 exhibit a thickness of 6 mm and 7 mm respectively.
Moreover, the distance in the axial direction between a plane P, which is axially median for said joining elements 8, and the respective free ends of said ribs 8a, is 20 mm in this preferred example.
- A second design of architecture for the support 1 according to the invention is illustrated in Fig. 4, with Figs. 5 to 12 illustrating variants of this second design (the structural elements analogous to those of Fig. 4 are hereinafter identified by reference numerals incremented by 10 for each Fig., starting from Fig. 5).
As in the stated first design, the supports 1 relating to these Figs. 4 to 12 are all of the type comprising said base 2, said crown 3 and an annular body 10.
* Fig. 4 shows such an annular body 10. This annular body consists of a circumferentially continuous supporting element 11 which comprises a set of partitions 12 connected two by two by joining elements 13.
The partitions 12 extend laterally on each side of the circumferential median plane P of the support 1 and they are regularly distributed around the circumference of said support 1. They have an angle of inclination A, relative to the circumferential direction, which approaches 90 degrees. The thickness H thereof is constant. Furthermore, two adjacent partitions 12 have an opposing angle of inclination relative to the axial direction.
These joining elements 13 have a thickness e, they are oriented circumferentially and each connects the respective ends of two adjacent partitions 12 which are arranged on the same side of the support 1 (these two ends are the ones closest to each other).
The joining elements 13 are thus arranged alternately in succession on each side of the partitions 12.
It will be noted that, in order to facilitate manufacture of the support 1 with axial demoulding, the supporting element 11 comprises no undercut elements.
* Fig. 5 shows a variant embodiment of a supporting element 21, with reference
to the supporting element 11 of Fig. 4.
The partitions 22 of this supporting element 21 have a thickness H in the central portion thereof which is greater than the thickness h thereof at the lateral ends of the partitions. In this example, H is approximately twice the size of h.
This variation in thickness imparts very good buckling resistance to the central portions of the partitions 22. The lateral ends are connected to the joining elements 23 in continuous manner, which imparts good buckling resistance thereto.
It will be noted that a variation in thickness of as little as 10% may have appreciable effects for the purpose of postponing the onset of overload buckling.
* Fig. 6 shows another variant embodiment of a supporting element 31.
As previously, this supporting element comprises partitions 32 which are connected by joining elements 33. The partitions 32 comprise two lateral portions 34 of the same angle of inclination A relative to the circumferential direction, which are offset circumferentially and are connected in the central portion of said supporting element 31 by a third portion 35 oriented substantially circumferentially.
The mean variation a in orientation between lateral portions 34 and the central portion 35 is of the order of 80 degrees in this case. Since the portions 35 are oriented circumferentially, the angles a and A are equal.
This presence of this third central portion 35, which has a mean orientation differing greatly from that of the two lateral portions, increases the buckling resistance of the central portion of the partitions 22.
It will be noted that, in order to be effective, this variation a must be greater than 20 degrees.
In this embodiment, the partitions 32 comprise, from one lateral end to the other, one reversal in the direction of the curvature thereof.
* Fig. 7 shows another variant embodiment of a supporting element 41.
In this case, the joining elements 43 which are arranged on one side of the supporting element 41 have a circumferential length which is less than that of the joining elements 44, which are arranged on the other side of the supporting element 41.
It will be noted that the substantially doubled length of the joining elements 44 increases the compressive stiffness of the supporting element 41 on this side of the support 1. This latter side should be arranged towards the interior side of the vehicle, where the loads borne by the support 1 while in operation are the greatest.
* Fig. 8 shows another variant embodiment of a supporting element 51.
In this case, the joining elements 53 are virtually reduced to the contact surface between the two lateral ends 54 as an arc of a circle of the partitions 52.
The partitions 52 also comprise a central connecting portion 55.
It will be noted that the variation a in mean orientation between the two lateral portions 56 and the central portion 55 is greater than 90 degrees and is of the order of 110 degrees, which increases the mean supporting density of the supporting element 51 in the central portion thereof.
From one lateral end to the other, these partitions 52 comprise three reversals in the direction of the curvature thereof.
* Fig. 9 shows another variant embodiment of a supporting element 61, a
variant similar to that of Fig. 8 with the following modifications.
The partitions 62 comprise rectilinear segments and exhibit three reversals in the direction of the curvature thereof. The partitions comprise two axially oriented lateral portions 64, which are connected, on the one hand, by a central portion 65 and, on the other hand, to the joining elements 63 by lateral ends 66 of a mean orientation y approaching 30 degrees, relative to the circumferential direction.
The mean variation a in orientation between the two axially oriented portions 64 of the partitions 62 and the central joining portion 65 is of the order of 40 degrees.
These joining elements 63 may in this case be defined as elements of a substantially triangular cross-section which are arranged between two adjacent lateral ends 66.
On both sides of the supporting element 61, the annular body 60 comprises a series of substantially axially oriented walls 67 which extends each joining element 63 towards the outside of the support 1. As may be seen in Fig. 9, the meeting of each joining element 63, of the said adjacent lateral ends 66 and of said axial wall 67 accordingly forms a three-branched star, which is highly resistant to buckling.
* Fig. 10 shows another variant embodiment of a supporting element 70 and, consequently, of a supporting element 71.
This latter element comprises partitions 72 with axially oriented central portions 74 which are extended on each side by a lateral end 75, which exhibits an orientation y approaching 30 degrees relative to the circumferential direction.
On one side of the annular body 70, the joining elements 73 are reduced to the contact surface between the two adjacent lateral ends 75. On the other side, the annular body 70 comprises lateral walls 76 which support the joining elements 77 on this side, said joining elements being of a substantially triangular shape.
It will be noted that on this latter side, the compressive stiffness of the supporting element is greater.
The length of the lateral walls 76 is in particular less than half the length of the central portions 74 of the partitions 72, so that they are not liable to buckle.
The side of the supporting element 71 having the highest radial compressive stiffness should preferably be arranged on the interior side of the vehicle. It has, in fact, been observed that the loads are highest on this interior side of the vehicle.
The partitions 72 have a thickness H in the central portion 74 thereof which is greater than the thickness h of the lateral portions 75 thereof, so as to increase the buckling resistance of this central portion 74.
* Fig. 11 shows another variant embodiment of a supporting element 80, a
variant very similar to said annular body 70 of Fig. 10.
This annular body 80 comprises axial lateral walls 86 and 87 which support the supporting element 81 on both sides, said supporting element also being structurally very similar to said supporting element 71.
For a given width of the annular body 80, these lateral walls 86 and 87 exhibit the advantage of reducing the axial width of the partitions 82 of the continuous supporting element 81 and thus of improving the buckling resistance of the overall structure. The axial lengths of said walls 86 and 87 may differ, as illustrated in Fig. 11.
* Fig. 12 shows an axial view of a support 1 including a supporting element 91
as described in Fig. 11, but additionally comprising a circumferential web 94 which is arranged
at half height of the annular body 90. This circumferential web 94, of cylindrical shape, exhibits
the advantage of bringing about a very substantial increase, of the order of a factor of four, of
the limit buckling load of the structure of the support 1.
Each of the supports 1 described with reference to Figs. 4 to 12 exhibits the following dimensional characteristics.
There are 40 partitions 12, ..., 92 around the circumference of each support 1, each partition exhibits a thickness of 8 mm and they are 40 mm apart. As has been stated above, each support 1 tested exhibits a width of 135 mm, a diameter of 440 mm and a height of 50 mm.
Furthermore, the base 2 and crown 3 of said support 1 exhibit a thickness of 6 mm and 7 mm respectively.
All the supporting elements 7, 11, ...,91 and the annular bodies 4, 10,..., 90 presented above may be manufactured by moulding techniques. In order to facilitate axial demoulding, they preferably comprise no undercut portions.
It will be noted that it would also be possible to use, as a support architecture according to the invention, a support consisting of two or more rings connected together in the axial direction of said support, the overall structure thereof remaining unchanged.
It could, for example, be possible to provide for such a support a first ring of a substantially rectangular axial section, and one or more annular elements comprising a plurality of recesses and extending substantially axially across the entire width thereof and distributed substantially regularly around the circumference thereof.
Such a ring-type support is easier to introduce into a tyre, due to the lower flexural rigidity of the various annular elements thereof.

WE CLAIM :
1) A safety support (1) intended to be mounted on a wheel rim inside a tyre, wherein said support (1) consists of a vulcanised rubber composition comprising (phr means parts by weight per 100 parts of diene elastomer(s)):
natural rubber or synthetic polyisoprene in a quantity of greater than or equal to 60 phr,
more than 60 phr of a reinforcing white filler, and from 3 to 8 phr of sulphur.
2) A safety support as claimed in claim 1, wherein said reinforcing
white filler consists of silica in a quantity ranging from 60 to 80 phr.
3) A safety support as claimed in claim 1 or 2, wherein said silica
exhibits BET or CTAB surface area values which are both in a range from
50 m2/g to 200 m2/g.
4) A safety support as claimed in claim 3, wherein said silica exhibits
BET or CTAB surface area values which are both in a range from 110
m2/g to 200 m2/g.
5) A safety support as claimed in one of the preceding claims, wherein
said composition comprises a reinforcing white filler/elastomer bonding
agent which is of the poly sulphurised alkoxysilane type.
6) A safety support as claimed in one of the preceding claims, wherein
said composition also has a homopolymer obtained by polymerisation of
a conjugated diene monomer having 4 to 12 carbon atoms, or a
copolymer obtained by copolymerisation of one or more conjugated

dienes with each other or with one or more vinyl aromatic compounds having from 8 to 20 carbon atoms, in a quantity of less than or equal to 40 phr.
7) A safety support as claimed in claim 6, wherein said composition
has a blend of natural rubber and polybutadiene.
8) A safety support as claimed in one of claims 1 to 5, wherein said
composition has a single diene elastomer consisting of natural rubber or
synthetic polyisoprene.
9) A safety support as claimed in one of the preceding claims, wherein
said composition exhibits an M10 elasticity modulus at 10% deformation
which is greater than 10 MPa.
10) A safety support substantially as herein described with reference to
the accompanying drawings.

Documents:

19-del-2001-abstract.pdf

19-del-2001-claims.pdf

19-del-2001-correspondence-others.pdf

19-del-2001-correspondence-po.pdf

19-del-2001-description (complete).pdf

19-del-2001-drawings.pdf

19-del-2001-form-1.pdf

19-del-2001-form-13.pdf

19-del-2001-form-18.pdf

19-del-2001-form-2.pdf

19-del-2001-form-3.pdf

19-del-2001-form-4.pdf

19-del-2001-form-5.pdf

19-del-2001-gpa.pdf

19-del-2001-petition-137.pdf

19-del-2001-petition-138.pdf

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Patent Number

226285

Indian Patent Application Number

19/DEL/2001

PG Journal Number

01/2009

Publication Date

02-Jan-2009

Grant Date

16-Dec-2008

Date of Filing

11-Jan-2001

Name of Patentee

SOCIETE DE TECHNOLOGIE MICHELIN

Applicant Address

23, RUE BRESCHET, FR-63000 CLERMONT-FERRAND, FRANCE.

Inventors:

#	Inventor's Name	Inventor's Address
1	FRANCOIS MASSON	660 HALTON ROAD # 8F, FREENVILLE, SOUTH CAROLINA 29607, UNITED STATES OF AMERICA.
2	FRANCOIS BATAILLE	RANDOL, 63450 ST-AMANT-TALLENDE, FRANCE.
3	SERGE TEISSEYRE	CITOYEN FRANCAIS, 12 PLACE DE LA RODADE, 63100 CLERMONT-FERRAND, FRANCE.

PCT International Classification Number

308L 23/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	00/00426	2000-01-12	France