Abstract:
A process and device for inflating a tire by forming, within an enclosure in which there are enclosed the rim and the beads of the tire, an inflation orifice between a first seat of the rim and a first bead, then introducing compressed air into said orifice and closing it such that the tire is inflated and mounted hermetically on the rim. Before forming this orifice, the first bead of the tire is located axially to the outside of the first seat and the second bead is mounted hermetically on the second seat, then, to form the orifice, points on the first bead are pressed. The device for implementing the process includes a bell formed of a fixed part and a mobile part intended to slide relative thereto to tightly surround the tire on the rim for its inflation, and including, within the bell, a finger for pressing at points on said bead.

Description:
BACKGROUND OF INVENTION 
     The present invention relates to a process and device for inflating a tire. The invention applies to the inflation of a tire, the beads of which are respectively intended to be mounted on peripheral seats of a special rim, this inflation being effected without using the valve of said rim. 
     The structure of this rim is described in detail in U.S. Pat. No. 5,836,366. 
     As can be seen in FIG. 1, to which reference will be made hereafter, said rim  10  comprises, starting from its peripheral edges formed of two projections  11  and  12 , a first and a second seat  13  and  14  inclined towards the outside and intended respectively to receive a first and a second bead  21  and  22  of the tire  20 . Between the seats  13  and  14  there is provided, firstly, a bearing surface  15  intended to receive a bearing support  23  for the tread  24  and, secondly, a mounting groove  16  connecting the bearing surface  15  to an axially inner flange  17  of said first seat  13 . 
     In the Test of the present description, by convention the seat which is adjacent to the groove  16  will be referred to as the first seat  13 , and the seat which is on the opposite side from said groove  16  will be referred to as the second seat  14 . 
     As for the axially outer flange of each seat  13 ,  14 , it is formed by the corresponding peripheral projection  11 ,  12 . 
     In known manner, the tire  20  is mounted on this special rim  10  in the following manner. 
     The first bead  21  is presented on the rim  10 , on the side of the second seat  14 , then this first bead  21  is slid axially over the bearing surface  15  so as to introduce it into the groove  16 . Then the second bead  22  is mounted on the second seat  14 . 
     Then, in an extraction step, the first bead  21  is extracted from the groove  16  so as to bring it axially against the outside of the projection  11  of the first seat  13 . 
     Finally, in a mounting stage, this first bead  21  is mounted on the first seat  13 . 
     Among the devices for inflating without using a valve which are known to date, mention may be made in particular of the device described in German Patent Specification DE-A-3 411 433, which comprises a bell formed of a cover of an upturned U-shaped cross-section. This bell is intended to be mounted hermetically in one of the sidewalls of a tire which has beforehand been mounted on the seats of a rim and which lies with its other sidewall flat on a horizontal support, also hermetically. 
     This rim comprises said seats on its inner face, and these seats are connected together by a planar central portion which is extended by two kinked sections directed towards the inside of the rim. Each seat is axially delimited, on the inner face of the rim, by one of said kinked sections and by a peripheral projection which forms an axial end of the rim and which is also directed towards the inside thereof, such that these seats are symmetrical to each other relative to said central portion. 
     When the tire is wedged between said support and said bell, the beads of the tire are thus mounted on said seats. 
     The bell is provided, within its internal space and close to its side wall, with four sliding means which may possibly also be pivoting means, such as levers, which are provided to bear on the upper bead located opposite the bell, so as to bring it towards the lower bead and thus to form an annular space between this upper bead and the rim, around the entire periphery of said bead. 
     Following the formation of this space, the tire is inflated by injecting compressed air into the bell and, consequently, between the tire and the rim via said space. Then said bearing means are caused to slide in the opposite direction, the effect of which is to reposition said upper bead on the corresponding seat, and the injection of compressed air into the bell is terminated, such that the tire is in the inflated state. 
     Mention may also be made, among the valve-less mounting devices, of those described in German Patent Specification DE-A-3 423 307 and in Belgian Patent Specification BE-A-888 537, which differ essentially from the former in that the bearing means which each of them comprises are formed by the cylindrical side wall itself of the corresponding bell, which is provided to be able to slide axially, that is to say, parallel to the axis of revolution of the tire. 
     One major disadvantage of these known inflation devices is that they are not suitable for inflating a tire mounted on a rim, such as the special rim described in the aforementioned U.S. Pat. No. 5,836,366, because, once said first bead of the tire has been mounted on said first seat of this special rim, the axially inner flange of this first seat and the aforementioned inclination of the latter towards the outside would hinder the circumferential deformation of this first bead towards said second bead, for creating said annular space. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to propose a process for inflating a tire and a device for implementing this process, which, in good conditions and in a reduced time, permit a tire to be inflated in relation with said special rim, which are thus defined: 
     this tire comprises beads respectively intended to be mounted on seats of a rim, there being provided between said seats, on one hand, a bearing surface intended to receive a bearing support for a tread and, on the other hand, a mounting groove connecting said bearing surface to an axially inner flange of one of said seats, or first seat, each seat being provided axially to the outside with a peripheral projection. 
     The inflation process according to the invention consists in forming an airtight enclosure, part of the wall of which is formed by said tire and within which there are enclosed said rim and said beads, then forming within said enclosure an inflation orifice between said first seat and one of said beads, or first bead, then introducing compressed air into said inflation orifice via said enclosure, then closing said orifice at the end of the inflation such that said tire is inflated and mounted hermetically on said rim. 
     According to the invention, said inflation process is characterized in that it consists, before forming said inflation orifice, in using said tire such that said first bead occupies an extraction position in which it is axially to the outside of said first seat and that the other bead, or second bead, is mounted in airtight manner on the other seat, or second seat, then, for forming said inflation orifice, pressing within said enclosure on a pinpoint location of the circumference of said first bead, then, for closing said orifice, ceasing pressure on said pinpoint location. 
     A device according to the invention for performing said process comprises a bell intended to be supplied with compressed air and formed of a fixed part and a mobile part intended to slide relative to the former, said parts being intended, respectively, to surround tightly in hermetically manner the sidewalls of said tire which is provided with said rim for its inflation. 
     According to the invention, said device is characterized in that it comprises, within said bell, a finger which is intended to exert an axial force at points on said first bead by means of its free end, in order to form an inflation orifice between said first bead and said first rim seat. 
     According to another characteristic of the invention, said inflation device is such that said finger is mounted to be mobile on the side of said fixed part and in translation parallel to the axis of sliding of said mobile part, under the control of a control element, such as a piston-cylinder unit. 
     Preferably, said finger has set back from its free end a shoulder, which is intended to bear on the outer face of said peripheral projection of the rim, such that the maximum amplitude of said translation is predetermined. 
     Preferably, said fixed part has a geometry of revolution which is concentric to said axis of sliding of said mobile part, and it is intended to bear with its peripheral edge on a circular zone of said sidewall. 
     Advantageously, said peripheral edge of said fixed part has, on an arc of its circumference, a portion slightly extending said edge by kinked sections beyond the remainder of said circumference, in the direction of said mobile part. 
     In this case, said finger is provided in an angular sector defined by a dihedron having said axis as its ridge and the faces of which pass respectively through said kinked sections. 
     According to another characteristic of the invention, said mobile part is provided with two annular, concentric wedges which are intended respectively to bear on the rim and on the tire. 
     In this manner, said fixed part can tightly surround said envelope in hermetic manner. 
     According to another characteristic of the invention, said inflation device comprises, within said bell, a mounting roller which is intended to bear on at least one arc of the circumference of said first bead, at the end of said inflation, so as to mount it on said first seat. 
     According to one example of embodiment, said mounting roller is mounted on the free end of an arm which is mobile in planar rotation about said axis, at various heights relative to said axis. 
     The aforementioned characteristics of the present invention, as well as others, will be better understood from reading the following description of an example of embodiment of the invention, which is given by way of illustration but not of limitation, said description being given in relation with the attached drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic section of an inflation device according to the invention in a first phase of the corresponding process, 
     FIG. 1 a  is an inset view showing an elevation of a detail of the device of FIG. 1, 
     FIG. 2 is a diagrammatic section of said inflation device in a second phase of said process, 
     FIG. 3 is a diagrammatic section of said inflation device in a third phase of said process, and 
     FIG. 4 is a diagrammatic section of said inflation device in a fourth phase of said process. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     As can be seen in FIG. 1, an inflation device  30  according to the invention comprises a frame  31 , a bell  32  which is mounted on the frame  31  and which is intended to cooperate with the tire  20  and the special rim  10 , and means  33  which are mounted within the bell  32  and which are intended to cooperate with the first bead  21  of the tire  20 . 
     The wall of the frame  31  is provided with an air inlet (not shown) which is connected hermetically to a compressed-air supply system. 
     In this example of embodiment, the bell  32  is formed of a fixed part  34  which is mounted on the frame  31  and a mobile part  35  which is provided to slide relative to the former by means of a control means  36 . 
     These parts  34  and  35  are intended, respectively, to surround the sidewalls  25  and  26  of the casing  20  hermetically for the purpose of inflation thereof, when said tire is provided with said rim  10 . 
     The fixed part  34  has a geometry of revolution, for example of cylindrical shape extended at a right-angle by a base  34   a , for fixing it to the frame  31 . 
     Preferably, the peripheral edge  34   b  of said fixed part  34  which is distal to said base  34   a  has, on a reduced arc of its circumference, a portion  34 b a  slightly extending said edge  34   b  beyond the rest of said circumference in the direction of said mobile part  35  (see the inset view of FIG. 1 a ). It can be seen in this FIG. 1 a  that this portion  34   ba  may be of substantially planar shape, and that it is, for example, connected to the rest of the circumference  34   bb  by two kinked sections  34   bc  which are symmetrical to each other and more of less curved. 
     The mobile part  35  is intended to exert, by means of the fixed part  34 , an axial clamping force on the tire  20  and on the rim  10  (see arrow A), the clamping intensity of which is controlled by the control means  36 . This part  35  has a wall which is overall perpendicular to that of the fixed part  34  and, in this example of embodiment, it is mounted to slide in its axis of symmetry X′X on said control means  36  (it can be seen in FIG. 1 that the fixed part  34  is concentric to said axis X′X). 
     This means  36  is formed here of a piston-cylinder unit, the rod  36   a  of which may be guided in both directions within a sleeve  31   a  extending, on the side of the fixed part  34 , the edge of an opening in the frame  31 , and the shank  36   b  of which is provided on the other side of same frame  31 . The rod  36   a  of the piston-cylinder unit  36  is provided with an element  36   c , such as a bolt, which is provided for locking it at a given stroke. 
     The mobile part  35  is provided, close to the periphery of its face opposite the fixed part  34 , with two concentric annular wedges  37  and  38  of sections which are for example rectangular, which are intended respectively to bear on the rim  10  and on the tire  20 . More precisely, the wedge  37  associated with the rim  10  is intended to bear on the outer face of the peripheral projection  11  of said rim  10 . As for the wedge  38  associated with the tire  20 , it is, firstly, located between said wedge  37  and the periphery of the mobile part  35  and, secondly, it extends said mobile part  35  in the direction of the fixed part  34  slightly beyond the wedge  37 , so as to be able to bear on the sidewall  26  of the tire  20  which ends in the second bead  22 . 
     The means  33  intended to cooperate with the first bead  21  of the tire  20  are formed, firstly, of a finger  33   a  which is intended to exert at points an axial force on the first bead  21  by means of its free end (see arrow B) in order to form an inflation orifice for the tire  20  and, secondly, a mounting roller  39  which is intended to bear on at least one arc of the circumference of said first bead  21 , at the end of said inflation. 
     In the example of FIG. 1, the finger  33   a  is mobile in both directions in translation parallel to the axis X′X, under the control of a control element  33   b , such as a second piston-cylinder unit which is mounted on the frame  31 . This finger  33   a  advantageously has a shoulder  33   c  set back from its free end. This shoulder  33   c  is intended to bear on the outer face of the peripheral projection  12  of the rim  10 , such that the maximum stroke of said second piston-cylinder unit and, consequently, the maximum amplitude of said translation are predetermined. 
     In the event that the peripheral edge  34   b  of the fixed part  34  has the aforementioned kinked section on an arc of the circumference in relation with FIG. 1 a , it will be noted that the finger  33   a  is then provided in the angular sector defined by a dihedron having as its ridge the axis X′X and the faces of which pass respectively through said kinked sections  34   bc.    
     As for the mounting roller  39 , it is mounted on the free end of an arm  39   a  which is mobile in planar rotation about the axis X′X, and at various heights relative to said axis X′X. 
     Advantageously, it will be noted that the inner space of the bell  32  on the outside of which the rim  10  provided with the tire  20  is intended to be mounted may be partially occupied, in order to reduce the volume of air necessary for inflating said tire  20 . According to one example of embodiment, to this end an element of revolution of annular structure (not shown) may be used which is mounted on said frame  31 , centered on the axis X′X. 
     An inflation device  30  according to the present invention function s in the following manner. 
     In a first stage, the result of which is illustrated in FIG. 1, the rim  10  integrally provided with the tire  20  is arranged in the extraction position, flat on the fixed part  34  of the bell  32  and on a predetermined side. 
     More precisely, this flat arrangement is such that the axis of revolution common to the tire  20  and to the rim  10  is merged with said axis of symmetry X′X of the device  30 . 
     As for this extraction position, it was obtained at the end of said extraction stage described above, and it is such that the first bead  21  of the tire is located axially to the outside of the projection  11  of the first seat  13 , the second bead  22 , for its part, being mounted on the second seat  14 . In this position, the first bead  21  bears virtually hermetically on said projection  11   
     As for said predetermined side being arranged flat on the fixed part  34 , this is the side of the tire  20  which comprises the first bead  21  in the extraction position. 
     As can be seen in FIG. 1, the tire  20  is then mounted on the peripheral edge  34   b  of the fixed part  34  by means of a circular zone of its sidewall  25 . 
     It will be noted that the implementation of this first step requires, firstly, the mobile part  35  of the bell  32  to occupy a position sufficiently distant from said edge  34   b  relative to the latter and, secondly, the means  33  intended to cooperate with the first bead  21  to occupy positions sufficiently distant from said edge  34   b  moving away from said mobile part  35 . 
     In a second stage, the result of which is also illustrated in FIG. 1, first of all the element  36   c  is actuated so as to form a stop for the mobile part  35 . Then the approach of said mobile part  35  is controlled by the means  36  until a given position thereof is reached on the axis X′X, such that the wedges  37  and  38  of said mobile part  35  then bear respectively on the outer face of the peripheral projection  11  of said rim  10  and on said sidewall  26  of the tire  20 . 
     More precisely, action is taken such that at least one of the wedges  37  and  38  bears hermetically on the rim  10  or on the tire  20 . Preferably, this sealing is effected by said wedge  37  on the rim  10 . 
     There has thus been formed an airtight enclosure  20 ,  32 , part of the wall of which is formed by the tire  20  and within which are enclosed the rim and the beads  21  and  22 . 
     In a third stage, the result of which is illustrated in FIG. 2, the translation of the finger  33   a  in the direction of the arrow B is then controlled until its free end bears on the first bead  21 , so as to bring the latter radially towards the outside and axially towards the inside of the projection  11  and thus to form said inflation orifice between the rim  10  and the tire  20 . 
     Then compressed air is injected into the bell  32 , the result of which is to introduce this air between the tire  20  and the rim  10 , via said orifice. 
     It will be noted that the preferred kinked section of the peripheral edge  34   b  in said portion  34   ba  makes it possible, by bearing on an arc of the circumference of the sidewall  25  adjacent to the first bead  21 , to facilitate the formation of this orifice to optimize later inflation. 
     Tests have shown that the action of the finger  33   a  on the first bead  21  makes it possible to increase the air pressure between the tire  20  and the rim  10  practically identically to what is in the remaining inner space of the bell  32 , which minimizes any return of compressed air outside said orifice. 
     In a fourth stage, an initial phase of which is illustrated in FIG. 3, the translation of the finger  33   a  is controlled in the opposite direction to that of the arrow B until it occupies a retracted position similar to that of FIG. 1, where it no longer bears on the bead  21 . The result of this is to close said inflation orifice and, consequently, to keep the compressed air between the rim  10  and the tire  20 . 
     The injection of compressed air into the bell  32  is then terminated, and the roller  39  is actuated in translation so as to make it adopt an initial mounting position (see FIG. 3) where it bears locally on the first bead  21  opposite, so as to mount the latter locally on the corresponding seat  13 . 
     It will be noted that, in the preferred embodiment in which the fixed part  34  has the aforementioned kinked section, said initial mounting position of said roller  39  is such that the latter is then on the inside of the angular sector defined by the aforementioned dihedron, following the example of the finger  33   a.    
     In a fifth stage (see FIG.  4 ), the mounting roller  39  is actuated in rotation about the axis X′X over a given path, in said mounting position. 
     Experience shows that the rotation of the roller  39  in this mounting position over a path equal to or slightly less than one rotation is sufficient to mount the first bead  21  on the seat  13  intended to receive it, perfectly hermetically. 
     In this way, the tire  20  is mounted hermetically on the rim  10 , while being inflated. This result is illustrated on the left-hand side of FIG. 4, where it can also be seen that after having controlled the stoppage of the rotation of the roller  39 , it has been actuated in translation so that it regains on the axis X′X its initial height of retraction relative to the bead  21 . 
     Then the compressed air contained in the bell  32  is withdrawn therefrom. It will be noted that this has no influence on the inflated state of the tire  20 , owing to the hermetic mounting thereof on the rim  10 . 
     The right-hand side of FIG. 4 illustrates the withdrawal of the mobile part  35  of the bell  32 , for extracting from the device  30  the assembly mounted in the inflated state of the tire  20  on the rim  10 . 
     Preferably, this withdrawal of the mobile part  35  is carried out in two stages, by means of the control means  36  and by unlocking the element  36   c.    
     First of all, this part  35  of the mounted assembly  10 ,  20  is slowly removed over only a few millimeters, so as to relax the force exerted thereby progressively. In a second step, the mobile part  35  of the mounted assembly  10 ,  20  can be removed in one operation by a height permitting the extraction of the latter. 
     It will be noted that the initial relaxation inherent in this first withdrawal step makes it possible to eliminate the risk of the beads sliding out of the corresponding seats  13  and  14 , which could have occurred in the case of sudden withdrawal effected in a single stage. 
     It will also be noted that an inflation device  30  in accordance with the present invention makes it possible to inflate a tire  20  located in the non-mounted state on the rim  10  and also, at the end of this inflation, the assembly of said tire  20  on said rim  10 .