Multidimensional drum for retreading process

Abstract

The present invention relates to a multidimensional drum (100) for holding a retreaded tire (200) and comprising at least two pluralities of segments (2) axially offset from each other, at least one plurality of segments (2) comprising a first shoulder (6) and at least one plurality of segments (2) comprising a second shoulder (7). According to the invention, the variable distance Lv between the first and second shoulders (6, 7) is axially variable, and the outside diameters Dv of at least one plurality of segments (2) comprising a first shoulder (6) and of at least one plurality of segments (2) comprising a second shoulder (7) are radially variable, the variations in the variable distance Lv and the variable diameter Dv allowing a wide variety of retreaded tires (200) to be mounted and inflated on the multidimensional drum (100).The invention also relates to a method implementing the multidimensional drum (100) of the invention. Figure 8.

Description

Title of the invention: Multidimensional drum for retreading process

[0001] The present invention relates to a multidimensional drum for inflating and rotating tires, and more specifically to a multidimensional drum for performing different operations on tires for the purpose of retreading them.

[0002] Tires usually have, at their periphery, a tread designed to wear down during rolling, comprising one or more components made of rubber materials of varying thicknesses. A tread most often includes a molded pattern with cutouts separating raised elements, designed to improve the tire's grip on the road.

[0003] During tire rolling, the tread wears down and its thickness decreases. When the tread thickness is no longer sufficient to properly perform the various functions of the tire, it must then be replaced.

[0004] So-called "retreading" processes and devices exist and allow only the tread of the worn tire to be replaced in order to extend its lifespan.

[0005] One of the first steps in retreading processes often consists of removing the tread from the worn tire. This tread removal step is usually carried out by known processes, such as, for example, machining or grinding processes.

[0006] In such processes, the machines used most often include: - a frame intended to support either a hub at the end of which a cylindrical drum is fixed, or a system comprising two cylindrical flanges, of diameters substantially equivalent to the diameters of the beads of the worn tire, and coming to rest on each side of said worn tire to grip it and form a sealed chamber with said worn tire, - a motorization system allowing the hub and the cylindrical drum to be rotated around the central axis of the cylindrical drum.

[0007] In what follows, the circumferential or longitudinal direction refers to the direction of rotation of a cylindrical drum, the axial or transverse direction refers to the direction parallel to the axis of rotation of the cylindrical drum, and the radial direction refers to a direction perpendicular to the axis of rotation of the cylindrical drum. An external axial direction corresponds to a direction from the hub supporting the cylindrical drum towards the cylindrical drum itself. Conversely, an internal axial direction corresponds to a direction from the cylindrical drum towards the hub.

[0008] The cylindrical drum usually comprises a cylindrical surface having at each end a cylindrical shoulder to form a rim. The cylindrical surface is generally covered with a membrane made of rubbery material.

[0009] The cylindrical drum thus reproduces the rim of the wheel on which the tire to be retreaded is usually mounted, that is to say that, when the tire to be retreaded is mounted on said cylindrical drum, the inner diameter of the tire to be retreaded corresponds to the diameter of the cylindrical surface of said cylindrical drum, and the distance between the two shoulders of the cylindrical drum corresponds to the distance between the outer surfaces of the two beads of said tire to be retreaded, said outer surfaces being the surfaces intended to come into contact with the rim edges of the wheel.

[0010] The inside diameter of the tire to be retreaded refers to the "seat diameter," that is, the diameter of the rim of the wheel on which the tire to be retreaded is intended to be mounted. This diameter is referred to, more simply, in what follows, as the bead diameter.

[0011] The distance between the outer surfaces of the two bead ribs of the tire to be retreaded corresponds to the distance between the contact faces of said bead ribs with the rim edges when the tire to be retreaded is mounted on a rim adapted to receive it. This distance is referred to, more simply, in what follows, as the distance between bead ribs.

[0012] As known to those skilled in the art, the cylindrical drum also includes an inflation device for pressurizing the tire to be retreaded to a predetermined pressure. Inflating the tire to be retreaded makes the outer surface of the tread of said cylindrical tire concentric with the axis of rotation of the cylindrical drum, thus facilitating retreading operations that require rotating the tire.

[0013] Most cylindrical drums used on retreading machines have a device allowing radial extension of the diameter of the cylindrical drum in order to be able to adapt to the different inner diameters of the tires to be retreaded, hence the name multidimensional drum, i.e. adapted to the mounting of tires of various dimensions.

[0014] These multidimensional drums do not have systems allowing for axial extension combined with radial extension. In order to be able to To accommodate varying bead spacing, different multi-dimensional drums are used, requiring lengthy and time-consuming drum changes on the retreading machine. To minimize downtime associated with these drum changes, retreading machines are organized into campaigns, each corresponding to the retreading of tires with a defined bead spacing. Furthermore, the large number of multi-dimensional drums needed to cover all tire dimensions represents a significant manufacturing and storage cost.

[0015] Document CN103600504B discloses a multidimensional drum used on a retreading machine. This multidimensional drum consists of several radially moving elements, said moving elements having a cylindrical external surface and being distributed circumferentially around the center of rotation of the multidimensional drum to form a substantially cylindrical surface that best fits the external surfaces of said moving elements. An elastic sealing membrane covers the substantially cylindrical external surfaces of the moving elements. Depending on the radial position of the moving elements, the diameter of the substantially cylindrical surface formed by the external surfaces of the moving elements varies. It is thus possible to adapt the diameter of the multidimensional drum to the tires to be retreaded.However, such a multidimensional drum does not allow for adaptation to the distance between the beading of the tires to be retreaded.

[0016] The object of the present invention is therefore to propose a multidimensional drum, for a retreading machine, allowing adaptation to tires to be retreaded whose inner diameter and distance between beads can vary within defined dimensional ranges.

[0017] The objects assigned to the invention are therefore aimed at remedying the aforementioned drawbacks and are achieved by means of a multidimensional drum intended for holding a tire to be retreaded, comprising: - a hub with axis of rotation XX' intended to support the multidimensional drum, - at least two plurality of segments, each plurality of segments being axially offset from one another, each plurality of segments comprising segments distributed circumferentially along a circumferential direction YY' tangent to the multidimensional drum, each segment being radially movable, along a radial direction ZZ' perpendicular to the axis of rotation XX', each segment having an external surface, the set of external surfaces forming an external surface of general cylindrical shape, - at least a plurality of segments forming a first outer surface of general cylindrical shape and variable outer diameter and comprising a first shoulder having a variable first shoulder diameter DI, - at least a plurality of segments forming a second outer surface of general cylindrical shape and variable outer diameter and comprising a second shoulder having a second variable shoulder diameter D2, said second shoulder being distant from the first shoulder by a variable distance Lv, - a sealing membrane extending from the first shoulder to the second shoulder, said sealing membrane covering the outer surface, said sealing membrane being deformable radially and axially, said sealing membrane comprising first and second rings of thickness Ea, said first ring cooperating with the first shoulder to form a first retaining zone intended to receive a first bead of the tire to be retreaded, said second ring cooperating with the second shoulder to form a second retaining zone intended to receive a second bead of the tire to be retreaded,said first and second holding zones having respectively first and second cylindrical surfaces of variable diameter Dv, , - at least one radial displacement means allowing variation of the variable diameters Dv, - a pneumatic system for inflating a sealed chamber, said sealed chamber being formed by the tire to be retreaded and by the sealing membrane, said multidimensional drum being characterized in that at least a plurality of segments comprising a first or a second shoulder is axially mobile and in that at least one axial displacement means allows to axially move the at least a plurality of segments comprising a first or a second shoulder to adjust the variable distance Lv.

[0018] Essentially, the multidimensional drum of the invention makes it possible to hold, pressurize, and rotate a wide variety of tire sizes to be retreaded. The number of multidimensional drums required to cover all tire sizes to be retreaded is thus greatly reduced.

[0019] When using retreading machines, it is no longer necessary to proceed by dimensional campaigns and the number of multidimensional drum changes is limited. The costs associated with these changes are thus reduced.

[0020] Advantageously, the waterproofing membrane has a hardness of at least 50 Shore A and at most 60 Shore A. This hardness allows the waterproofing membrane to remain flexible, thus ensuring a good seal between the waterproofing membrane and the first and second ribs of the tire to be retreaded when inflating the airtight chamber.

[0021] Preferably, the thickness Ea of the first and second ring is at least equal to 10 mm and at most equal to 20 mm, which makes it possible to avoid too much faceting of the outer surface of the multidimensional drum and to maintain good cylindricity of the variable diameter Dv of the sealing membrane even when said diameters Dv increase during the radial expansion of said multidimensional drum.

[0022] Preferably, the axial displacement means is driven by an electric, pneumatic, hydraulic or electromagnetic actuator.

[0023] In an advantageous embodiment, the axial displacement means comprises: - at least one flange connected to each segment of a plurality of segments comprising a first or a second shoulder, the connection to each segment of a plurality of segments being made via a radial sliding connection, said at least one flange having a thread concentric with the axis of rotation XX', - a circular spindle having an external thread concentric with the axis of rotation XX' and intended to cooperate with the tapping of at least one flange, - a brake enabling the circular spindle to be locked in rotation when the entire multidimensional drum including the flange is set in rotation, the rotation of the flange carried out simultaneously with the locking of the circular spindle generating an axial displacement of at least one flange and of the plurality of segments connected to at least one flange.

[0024] In this embodiment, the axial displacement system does not require the addition of an additional rotary or linear actuator; only the rotation of the entire multidimensional drum associated with a brake system allows the variable distance Lv to be modified.

[0025] Preferably, the plurality of segments comprising the first shoulder and the plurality of segments comprising the second shoulder are both axially mobile. The mobility of the plurality of segments comprising the first and second shoulders respectively allows for faster modification of the distance Lv and thus reduces cycle time.

[0026] Advantageously, at least one synchronization means allows the axial displacement of the plurality of segments comprising the first shoulder in a direction opposite to the direction of axial displacement of the plurality of segments comprising the second shoulder, the axial displacement of the plurality of segments comprising the first shoulder and the axial displacement of the plurality of segments comprising the second shoulder taking place at the same linear speed.

[0027] The synchronization means allows the median circumferential plane of the tire to be retreaded to always be positioned at the same axial position relative to a reference frame external to the multidimensional drum. This simplifies the axial movements of the tools external to the multidimensional drum used during the retreading operations. The axial movement of these tools does not necessarily need to be large to cover the entire width of the tire being retreaded.

[0028] Preferably, the synchronization means is of the mechanical, hydraulic or electrical type.

[0029] In certain embodiments, three pluralities of segments are radially mobile and cooperate to form the outer surface, such that: - a first plurality of segments is axially mobile and includes the first shoulder cooperating with the outer surface to form the first retaining area intended to receive the first bead of the tire to be retreaded, - a second plurality of segments is axially mobile and includes the second shoulder cooperating with the outer surface to form the second retaining area intended to receive the second bead of the tire to be retreaded, - a third plurality of segments is axially interposed between the first and second plurality of segments, said third plurality of segments being axially fixed.

[0030] The use of three pluralities of segments with a third plurality of segments interposed axially between the first and second pluralities of segments makes it possible to obtain a simple axial displacement system with a limited number of pluralities of segments.

[0031] Preferably, the radial displacement means is a pneumatic, hydraulic, electrical or electromagnetic system.

[0032] Advantageously, the radial displacement system comprises: - a movable part having a conical outer surface, said conical outer surface having a cone axis that is concentric with the axis of rotation XX', said movable part performing a displacement along an axial direction, - a plurality of mobile sectors distributed circumferentially along a circumferential direction YY', each mobile sector being able to move radially, each segment being connected via an axial sliding link to at least one mobile sector, each mobile sector having an inclined surface cooperating with the conical outer surface to allow the transmission of an identical radial movement to each segment, the radial movement being able to be an extension or retraction movement depending on the direction of the axial movement carried out by the moving part.

[0033] The use of an axially movable conical part transmitting radial motion to the various moving sectors eliminates the need for a radial actuator for each moving sector. The radial movement system is thus simplified and does not require a multitude of radial actuators.

[0034] Advantageously, the inclined surface of the moving sectors cooperates with the conical outer surface via a sliding joint. The use of a sliding joint between the inclined surface of the moving sectors and the conical outer surface makes it easy to obtain a reversible system; that is, an axial movement of the moving part in one direction allows for an extension of the moving sectors, and an axial movement of the moving part in the opposite direction allows for the retraction of the moving sectors without the use of an additional system.

[0035] Advantageously, the inclined surface of the movable sectors cooperates with the conical outer surface via a contact joint. The radial retraction of the movable sectors is achieved through the elasticity of the sealing membrane, which presses radially on the segments of the various pluralities of segments. The contact joint between the inclined surface of the movable sectors and the conical outer surface allows for a simple and inexpensive system, thanks in particular to the return function of the movable sectors, which is achieved through the elasticity of the sealing membrane.

[0036] The invention also relates to a retreading process using the multidimensional drum defined above, said retreading process comprising the following steps: - transport of tires to be retreaded, said tires to be retreaded being of different types and sizes, - Determination of the diameter of the beads Db and the distance between the beads Lb of a tire to be retreaded, - activation of the axial displacement means to achieve an axial extension movement until the variable distance Lv is greater than the distance between the ridges Lb, - activation of the radial displacement means to perform a radial retraction movement until the first and second shoulder diameters are smaller than the diameters of the first and second beads of the tire to be retreaded, - placement of the tire to be retreaded on the multidimensional drum, the axis of rotation of the tire to be retreaded being substantially parallel to the axis of rotation XX', the first and second beads resting on the sealing membrane, - activation of the axial displacement means to achieve an axial retraction movement of the multidimensional drum until the variable distance Lv is equal to the distance between the ridges Lb, - activation of the radial displacement means to achieve a radial extension movement of the diameter Dv until the first and second beads press on the sealing membrane with a pressure Pb, - activation of the pneumatic system to inject air into the sealed chamber to inflate the tire to be retreaded to a pressure P, - rotation of the multidimensional drum to perform the retreading work on the tire to be retreaded, - activation of the pneumatic system to remove some of the air contained in the sealed chamber in order to deflate the tire to be retreaded, - activation of the axial displacement means to achieve an axial retraction movement of the multidimensional drum to obtain a variable distance Lv less than the distance between the ridges Lb, - activation of the radial displacement means to achieve a radial retraction movement of the multidimensional drum until the first and second shoulder diameters D1, D2 are smaller than the diameters of the first and second bead of the tire to be retreaded, - Removal of the tire to be retreaded from the multidimensional drum.

[0037] The implementation of the method of the invention makes it possible to perform retreading operations on a wide variety of tire sizes without changing the multidimensional drum. Furthermore, the mounting of the tire to be retreaded onto the multidimensional drum is simplified thanks to the variable distance Lv, which can be greater than the distance between the beads Lb.

[0038] Preferably, the pressure P is at least 1 bar and at most 1.5 bar. The ability to vary the pressure in the sealed chamber allows the pressure to be adapted to the mechanical resistance requirements of the tire being retreaded during the retreading operations. Some operations require the application of a tool to the tread of the tire being retreaded, which must nevertheless maintain good cylindricality during rotation.

[0039] Preferably, the bearing pressure Pb is at least 3 bar and at most 8 bar, and more preferably at least 4 bar and at most 7 bar. The bearing pressure Pe, combined with the elasticity of the sealing membrane material and the respective thickness Ea of the first and second rings, ensures good sealing of the airtight chamber with any diameter value Dv.

[0040] Other objects, features and advantages of the invention will become apparent in more detail from the following description and from the accompanying drawings, provided purely for illustrative and non-limiting purposes, among which: -[Fig.1]: Cross-sectional view along a radial plane of a tire to be retreaded. -[Fig.2]: Partial view, without the sealing membrane and in perspective of a multidimensional drum according to the invention, said multidimensional drum being in the most retracted position possible. -[Fig.3]: Partial view, without the sealing membrane and in perspective of a multidimensional drum according to the invention, said multidimensional drum being expanded in an intermediate position. -[Fig.4]: Perspective view of an example of a mechanical synchronization system for the multidimensional drum, with some parts of said multidimensional drum removed. -[Fig.5]: Front view of a tire to be retreaded placed on the multidimensional drum before the dimensional adaptation steps of the multidimensional drum. -[Fig.6]: Cross-sectional view of a tire to be retreaded placed on the multidimensional drum before the dimensional adaptation steps of the multidimensional drum, the cross-sectional view being taken according to the cutting plane AA as defined on [Fig.5]. -[Fig.7]: Overview and perspective view of a tire to be retreaded after the dimensional adaptation steps of the multidimensional drum. -[Fig.8]: Cross-sectional view of a tire to be retreaded, inflated and held by the multidimensional drum, the cross-sectional view being taken along a plane radial to the axis of rotation of the multidimensional drum.

[0041] The present invention relates to a multidimensional drum 100 intended for holding a tire to be retreaded 200.

[0042] As can be seen in [Fig.1], a retreaded tire 200 comprises a first and a second bead 10, 11 separated axially by a distance between the beads Lb corresponding to the greatest distance between the lateral faces of the first and second beads 10, 11. Furthermore, the first and second beads 10, 11 also comprise an inner diameter called the bead diameter Db.

[0043] The multidimensional drum 100 comprises, as can be seen in [Fig. 6] and [Fig. 8], a hub 1 with axis of rotation XX' and intended to support the multidimensional drum 100. The hub 1 cooperates with a fixed frame of a retreading machine and with a rotation system, enabling said hub 1, and consequently the multidimensional drum 100, to rotate at a rotational speed predetermined. The fixed frame of a retreading machine and the rotation system are conventional systems as known to those skilled in the art and are not shown in the figures.

[0044] The multidimensional drum 100 also comprises at least two plurality of segments 2, and as can be seen in [Fig.2] and in Figures 6 and 8, each plurality of segments 2 is axially offset from one another, each plurality of segments 2 comprises segments 3 distributed circumferentially along a circumferential direction YY' tangent to the multidimensional drum 100, each segment 3 being radially movable, along a radial direction ZZ' perpendicular to the axis of rotation XX', each segment 3 having an external surface 4, the set of external surfaces 4 forming an external surface 5 of generally cylindrical shape.

[0045] As is always represented on [Fig.2] and on figures 6 and 8, each segment 3 comprises, in any circumferential plane YZ perpendicular to the axis of rotation XX', an external surface 4 in the form of an arc of a circle, the set of external surfaces 4 of each plurality of segments 2 cooperating to form the external surface 5 of general cylindrical shape and variable external diameter.

[0046] As can be seen in [Fig. 2] and [Fig. 3], and as is known to those skilled in the art, each segment 3 also includes edges parallel to the axis of rotation XX', each parallel edge being comb-shaped. The comb shape is a succession of "teeth" and "hollows," and each tooth of an edge of segment 3 cooperates with a hollow of the edge of the adjacent segment 3. As shown in [Fig. 2], when the diameter is minimal, the teeth and hollows are contiguous, i.e., there is no clearance between them. As can be seen in [Fig. 3], when the diameter increases, i.e., when the segments 3 move radially outwards, clearance appears between the teeth and hollows, but the outer surface 5 retains a general cylindrical shape circumscribed by the various outer surfaces 4 of the different segments 3.

[0047] The multidimensional drum 100 further comprises: - at least a plurality of segments 2 forming a first external surface 61 of generally cylindrical shape and variable external diameter and comprising a first shoulder 6 having a variable first shoulder diameter DI, - at least a plurality of segments 2 forming a second outer surface 62 of general cylindrical shape and variable outer diameter and comprising a second shoulder 7 having a second variable shoulder diameter D2, said second shoulder 7 being distant from the first shoulder 6 by a variable distance Lv.

[0048] As can be seen in [Fig.2] and [Fig.3], the first and second shoulders 6, 7 can be circumferentially continuous when the multidimensional drum 100 is retracted to the maximum or can be circumferentially discontinuous when the multidimensional drum 100 extends radially.

[0049] The first and second shoulder diameters D1, D2 correspond to the diameters of a cylinder circumscribed to the different most radially external surfaces of the first and second shoulders 6, 7 respectively.

[0050] The multidimensional drum 100 further comprises a sealing membrane 14 extending from the first shoulder 6 to the second shoulder 7, said sealing membrane 14 covering the outer surface 5, said sealing membrane 14 being deformable radially and axially, said sealing membrane 14 comprising first and second rings 31, 32 of thickness Ea, said first ring 31 cooperating with the first shoulder 6 to form a first retaining zone 8 intended to receive a first bead 10 of the tire to be retreaded 200, said second ring 32 cooperating with the second shoulder 7 to form a second retaining zone 9 intended to receive a second bead 11 of the tire to be retreaded 200, said first and second retaining zones 8, 9 having respectively first and second cylindrical surfaces 11, 12 of variable diameter Dv.

[0051] The variable diameter Dv corresponds to the diameter of a circle circumscribed about the first and second cylindrical surfaces 11, 12.

[0052] The sealing membrane 14 is made of an elastic material allowing radial and axial deformation of said sealing membrane 14.

[0053] The portions of the sealing membrane 14 covering the first and second outer surfaces 61, 62 are fixed axially and can only expand radially. The fixing can be achieved, for example, by shrink-fitting using the elasticity of the sealing membrane 14. Fixing by spot bonding, riveting, or bolting can also be used.

[0054] The sealing membrane 14 may have a shape of revolution with axis of rotation XX', said shape of revolution being smooth between the first and second rings 31, 32 as shown in [Fig.6] and [Fig.8], or may, as is known to those skilled in the art, have an "accordion" shape allowing the sealing membrane 14 to more easily follow the axial evolution of the distance Lv between the first and second shoulders 6, 7.

[0055] The sealing membrane 14 can be monobloc or made in several parts assembled together by sealing fastening means.

[0056] The sealing membrane 14 can be manufactured, for example, by molding, extrusion or calendering processes, some of these processes being able to be combined with assembly processes using watertight fixing means to obtain a sealing membrane 14 having the desired shape.

[0057] The multidimensional drum 100 includes at least one radial displacement means 17 allowing the variable diameters Dv to be varied.

[0058] The at least one radial displacement means 17 allows all segments 3 of the pluralities of segments 2 comprising the first and second shoulders 6, 7 to be moved radially and simultaneously in order to maintain the outer surface 5 of general cylindrical shape.

[0059] The multidimensional drum 100 further includes a pneumatic system 15 for inflating a sealed chamber 16, said sealed chamber 16 being formed by the tire to be retreaded 200 and by the sealing membrane 14.

[0060] When the first and second beads 10, 11 of the tire to be retreaded 200 are positioned in the first and second holding zones 8, 9 near the first and second shoulders 6, 7, the inflation of the sealed chamber 16 makes it possible to press said first and second beads 10, 11 against the first and second shoulders 6, 7 and to pressurize the tire to be retreaded 200 under conditions similar to pressurizing said tire to be retreaded 200 mounted on the rim of a wheel.

[0061] The seal between the sealing membrane 14 and the tire to be retreaded 200 is achieved by means of the support of the first and second beads 10, 11 against said sealing membrane 14, said support being made in the first and second holding zones 8, 9.

[0062] The first and second ridges 10, 11 are held in axial position by means of the first and second shoulders 6, 7 which have first and second shoulder diameters D1, D2 sufficiently large to serve as an axial stop and prevent the separation of said first and second ridges 10, 11.

[0063] The pneumatic system 15, partially shown in the various figures, may include, by way of example and as known to those skilled in the art: - a pneumatic rotary joint located at one end of the hub 1 and connected to a compressed air generation device such as a piston compressor, - at least one compressed air delivery channel connected on one side to the rotary joint and on the other side to the sealed chamber 16. The compressed air delivery channel may be, by way of example, a flexible polyamide 11 hose of the "rilsan" type running through different cavities to connect the rotary joint to the sealed chamber 16.

[0064] The multidimensional drum 100 is characterized in that at least a plurality of segments 2 comprising a first or second shoulder 6, 7 is axially movable and in that at least one axial displacement means 18 allows movement axially at least a plurality of segments 2 including a first or second shoulder 6, 7 to adjust the variable distance Lv.

[0065] Advantageously, the sealing membrane 14 has a hardness of at least 50 shore A and at most 60 shore A, this hardness being obtainable by making said sealing membrane 14 in a material such as silicone, rubber, or elastomeric thermoplastic.

[0066] Advantageously, the thickness Ea of the first and second ring 31, 32 is at least equal to 10 mm and at most equal to 20 mm.

[0067] Preferably, the axial displacement means 18 is driven by an electric, pneumatic, hydraulic, or electromagnetic actuator, which may be, for example, a linear or rotary actuator. In the case of a rotary actuator, the rotational motion is converted into radial linear motion by screw / nut systems.

[0068] In certain embodiments, the axial displacement means 18 comprises: - at least one flange 19 connected to each segment 3 of a plurality of segments 2 comprising a first or a second shoulder 6, 7, the connection to each segment 3 of a plurality of segments 2 being made by means of a radial sliding connection 20, said at least one flange 19 having a thread 21 concentric with the axis of rotation XX', - a circular spindle 23 having an external thread 22 concentric with the axis of rotation XX' and intended to cooperate with the tapping 21 of at least one flange 19, - a brake 24 allowing the circular spindle 23 to be locked in rotation when the entire multidimensional drum 100 including the flange 19 is set in rotation, the rotation of the flange 19 carried out simultaneously with the locking of the circular spindle 23 generating an axial displacement of at least one flange 19 and of the plurality of segments 2 connected to at least one flange 19.

[0069] The addition of a radial sliding link 20 between at least one flange 19 and each segment 3 of a plurality of segments 2 allows axial movement of all said segments 3 regardless of their radial positioning.

[0070] As illustrated in [Fig. 2], the radial slide connection 20 can be achieved, for example, by a U-shaped part cooperating by radial sliding with the circular flange 19. Other slide systems, such as rod systems cooperating with bushings, can also be used.

[0071] The brake 24, which allows the circular spindle 23 to be locked in rotation, is fixed with respect to the rotational movement of the multidimensional drum 100. This brake 24 can, for example, be fixed to the frame of the retreading machine on which the multidimensional drum 100 is mounted or connected to any other fixed element external to the multidimensional drum 100.

[0072] Some unclaimed embodiments include, instead of the brake 24, a manual actuation system, such as a handwheel or a crank, connected to the circular spindle 23 and allowing the circular spindle 23 to be rotated to achieve the axial displacement of at least one flange 19 and of the plurality of segments 2 connected to at least one flange 19.

[0073] As can be seen in Figures 6 and 8, the external thread 22 of the circular spindle 23 cooperates with the tapped hole 21 of the flange 19 to form a screw / nut type system allowing axial movement of the flange 19 when the multidimensional drum 100 is rotated and when the brake 24 is activated.

[0074] Preferably, the plurality of segments 2 comprising the first shoulder 6 and the plurality of segments 2 comprising the second shoulder 7 are both axially mobile.

[0075] In embodiments comprising an axial displacement means 18 comprising: - a first flange 19 connected to each segment 3 of the plurality of segments 2 comprising a first shoulder 6, - a second flange 19 connected to each segment 3 of the plurality of segments 2 comprising a second shoulder 7, the tapping 21 of the first flange 19 has a reverse pitch compared to the tapping 21 of the second flange 19. Thanks to these reverse steps, the variable distance Lv can be reduced or increased when the multidimensional drum 100 is rotated and when the brake 24 is activated.

[0076] Advantageously, at least one synchronization means 25 allows the axial displacement of the plurality of segments 2 comprising the first shoulder 6 in a direction opposite to the direction of axial displacement of the plurality of segments 2 comprising the second shoulder 7, the axial displacement of the plurality of segments 2 comprising the first shoulder 6 and the axial displacement of the plurality of segments 2 comprising the second shoulder 7 taking place at the same linear speed.

[0077] Preferably, the synchronization means 25 is of the mechanical, hydraulic or electrical type.

[0078] As can be seen in [Fig. 4], the mechanical synchronization means 25 may comprise a pinion 31 cooperating with two racks 32, one of the racks 32 being linked to a first sliding rod 33 fixed to at least one of the segments 3 of the plurality of segments 2 comprising the first shoulder 6, the other rack 32 being linked to a second sliding rod 34 fixed to at least one of the segments 3 of the plurality of segments 2 comprising the second shoulder 7. The first and second sliding rods 33, 34 slide in an axial direction and the pinion 31 is mobile in rotation so that any axial displacement of the first sliding rod 33 causes, via the first rack 32, the rotation of the pinion 31 which in turn causes the displacement of the second sliding rod 34 via the second rack 32, the displacement of the second sliding rod 34 being in the opposite direction to the displacement of the first sliding rod 33 and with the same linear speed.

[0079] Electrical synchronization systems may include, for example, position sensors and a servo system for controlling electric linear actuators to move simultaneously and in opposite directions the plurality of segments 2 comprising the first and second shoulders 6, 7.

[0080] Hydraulic synchronization systems may include, for example, servovalves and positioning sensors to control hydraulic linear actuators to move simultaneously and in opposite directions the plurality of segments 2 comprising the first and second shoulders 6,7.

[0081] In an embodiment illustrated by [Fig.6] and [Fig.8], three pluralities of segments 2 are radially mobile and cooperate to form the outer surface 5, such that: - a first plurality of segments 51 is axially mobile and includes the first shoulder 6 cooperating with the outer surface 5 to form the first retaining zone 8 intended to receive the first bead 10 of the tire to be retreaded 200, - a second plurality of segments 52 is axially mobile and includes the second shoulder 7 cooperating with the outer surface 5 to form the second retaining zone 9 intended to receive the second bead 11 of the tire to be retreaded 200, - a third plurality of segments 53 is interposed axially between the first and second plurality of segments 51, 52, said third plurality of segments 53 being fixed axially.

[0082] In this embodiment, as shown in [Fig. 6] and [Fig. 8], the first, second, and third pluralities of segments 51, 52, 53 form at least partially overlapping cylindrical tubes that can slide at least partially within one another. As can be seen in [Fig. 6] and [Fig. 8], the diameters of the cylindrical tubes formed by the first, second, and third pluralities of segments 51, 52, 53 are close enough to form an outer surface 5 of generally cylindrical shape and the sealing membrane 14, extending from the first shoulder 6 to the second shoulder 7. can rest on said outer surface 5 without undergoing significant changes in diameters.

[0083] In this embodiment, the third plurality of segments 53 is axially fixed, but a variant could be envisaged in which this third plurality of segments 53 would be axially mobile.

[0084] Preferably, the radial displacement means 17 is a pneumatic, hydraulic, electrical, or electromagnetic system, which may be, for example, a linear or rotary actuator. In the case of a rotary actuator, the rotational motion is converted into radial linear motion by screw / nut systems.

[0085] In certain embodiments, the radial displacement system 17 comprises: - a movable part 26 having a conical outer surface 27, said conical outer surface 27 having a cone axis which is concentric with the axis of rotation XX', said movable part 26 performing a displacement along an axial direction, - a plurality of movable sectors 28 distributed circumferentially along a circumferential direction, each movable sector being able to move radially, each segment 3 being connected via an axial sliding link 29 to at least one movable sector 28, each movable sector 28 having an inclined surface 30 cooperating with the conical outer surface 27 to allow the transmission of an identical radial movement to each segment 3, the radial movement being able to be an extension or retraction movement depending on the direction of the axial movement carried out by the movable part 26.

[0086] The moving part 26 can be the end of the piston of an electric, pneumatic or hydraulic cylinder as shown in [Fig.6] and [Fig.8].

[0087] The movable sectors 28 can be parts having two parallel radial edges and sliding in grooves made in discs having faces perpendicular to the axis of rotation XX', the discs being located on either side of said movable sectors 28. Other sliding systems, such as rails, rods cooperating with bushings, can be suitable for sliding the movable sectors 28.

[0088] The axial sliding connection 29 can be achieved, for example, by a rod system sliding in a smooth sleeve.

[0089] The addition of an axial sliding link 29 between each movable sector 28 and one of the segments 3 of the at least a plurality of segments 2 allows the radial movement of all said segments 3 regardless of their axial positioning.

[0090] In certain embodiments, the inclined surface 30 of the movable sectors 28 cooperates with the conical outer surface 27 by means of a sliding joint. The use of a sliding joint between the inclined surface 30 of the movable sectors 28 and the conical outer surface 27 makes it easy to obtain a reversible system, i.e. that an axial movement of the moving part 26 in one direction allows an extension movement of the moving sectors 28 and an axial movement of the moving part 26 in the opposite direction allows the retraction of the moving sectors 28 without the use of an additional system.

[0091] As shown in Figures 6 and 8, in a particular embodiment, the inclined surface 30 of the movable sectors 28 cooperates with the conical outer surface 27 by a contact connection, the radial retraction of the movable sectors 28 being achieved thanks to the elasticity of the sealing membrane 14 pressing radially on the segments 3 of the different pluralities of segments 2.

[0092] As can be seen in Figures 6 and 8, when the cone is moved axially and outwards, the inclined surfaces 30 of each moving sector 28 slide on the conical outer surface 27 causing a radial extensional displacement of each moving sector 28. As is known to those skilled in the art, when the angle of the cone of the conical outer surface 27 is known, it is possible to define the value of the radial displacement of each moving sector 28 by determining the value of the axial displacement of the moving part 26.

[0093] Conversely, and as is always represented [Fig.6] and [Fig.8], when the cone is moved axially inwards, the inclined surfaces 30 of each movable sector 28 cooperate with the sealing membrane 14 and, thanks to the elasticity of said sealing membrane 14, slide on the conical outer surface 27 causing a radial retraction displacement of each movable sector 28.

[0094] The invention also relates to a retreading process using the previously defined multidimensional drum 100.

[0095] The retreading process of the invention can be implemented by the control of an industrial programmable logic controller (PLC).

[0096] The retreading process of the invention using the multidimensional drum 100 is characterized in that it includes a first step of conveying the tires to be retreaded 200, said tires to be retreaded 200 being able to be of different types and sizes.

[0097] Thanks to the use of the multidimensional drum 100, it is not necessary to sort the tires to be retreaded 200 according to their sizes and it is not necessary to work in campaigns.

[0098] In retreading workshops implementing the process of the invention, the conveyance of the tires to be retreaded 200 to the retreading machine using the multidimensional drum 100 can be done using, for example, conveyors, manual trolleys or automatic guided vehicles (AGV).

[0099] The retreading process of the invention using the multidimensional drum 100 is characterized in that it includes a second step of determining a diameter of the beads Db and a distance between the beads Lb of a tire to be retreaded 200.

[0100] The determination of the diameter of the beads Db and the distance between the beads Lb of a tire to be retreaded 200 can be done automatically using, for example, optical reading systems such as cameras, to read on the sides of the tire to be retreaded 200 the dimensions and the type of tire to be retreaded 200 or measuring systems, such as lasers, which will measure the dimensions of the tire to be retreaded 200.

[0101] The determination of the diameter of the beads Db and the distance between the beads Lb of a tire to be retreaded 200 can also be carried out manually by an operator by reading the dimensions on the sidewalls of the tire to be retreaded 200 or using measuring devices to determine the dimensions of said tire to be retreaded 200.

[0102] A third step of the process is carried out by activating the axial displacement means 18 to achieve an axial extension movement until the variable distance Lv is greater than the distance between the ridges Lb.

[0103] A fourth step is carried out by activating the radial displacement means 17 to perform a radial retraction movement until the first and second shoulder diameters D1, D2 are smaller than the diameters of the first and second bead 10, 11 of the tire to be retreaded 200.

[0104] As illustrated in [Fig.5] and [Fig.6], a fifth step is carried out by placing the tire to be retreaded 200 on the multidimensional drum 100, the axis of rotation of the tire to be retreaded 200 being substantially parallel to the axis of rotation XX', the first and second beads 10, 11, resting on the sealing membrane 14. As shown in [Fig.6], the first and second beads 10, 11 are positioned axially between the first and second shoulders 6, 7.

[0105] The installation of the tire to be retreaded 200 can be done manually by an operator or automatically using Cartesian or multi-articulated robots equipped with grippers allowing the retreaded tire 200 to be grasped.

[0106] The sixth step of the method comprises activating the axial displacement means 18 to perform an axial retraction movement of the multidimensional drum 100 until the variable distance Lv is equal to the distance between the ridges Lb. To determine when the variable distance Lv is equal to the distance between the ridges Lb, various systems can be used, such as pressure sensors, optical systems, or proximity sensors. determine when the first and second ridges 10,11 come into contact with the first and second shoulders 6,7 respectively.

[0107] The method includes a seventh step of activating the radial displacement means 17 to achieve a radial extension movement of the diameter Dv until the first and second beads 10, 11 press on the sealing membrane 14 with a pressure Pb.

[0108] The support pressure Pb can be obtained by using, for example, at least one pressure sensor placed between the sealing membrane 14 and the first and second external surfaces 61, 62.

[0109] Depending on the type and dimensions of the tire to be retreaded 200 and the hardness of the sealing membrane 14, the support pressure Pb can be adjusted. The different Pb pressure values ​​to be applied can be determined by preliminary tests, numerical simulation techniques, machine learning, or artificial intelligence.

[0110] The eighth step is carried out by activating the pneumatic system 15 to inject air into the sealed chamber 16 to inflate the tire to be retreaded 200 to a pressure P. At the end of the eighth step, and as shown in Figures 7 and 8, the tire to be retreaded 200 is inflated and held in position on the multidimensional drum 100.

[0111] The ninth step of the process includes rotating the multidimensional drum 100 to perform the retreading work on the tire to be retreaded 200.

[0112] When the retreading work is completed, the process includes a tenth step in which the pneumatic system 15 is activated to remove some of the air contained in the sealed chamber 16 to deflate the tire to be retreaded 200.

[0113] The method includes an eleventh step in which the axial displacement means 18 is activated to achieve an axial retraction movement of the multidimensional drum 100 to obtain a variable distance Lv less than the distance between the ridges Lb.

[0114] The twelfth step is carried out by activating the radial displacement means 17 to achieve a radial retraction movement of the multidimensional drum 100 until the first and second shoulder diameters D1, D2 are less than the diameters of the first and second bead 10, 11 of the tire to be retreaded 200.

[0115] It is of course possible to carry out the eleventh and twelfth steps simultaneously in order to reduce the cycle time of the process of the invention.

[0116] The thirteenth and final step involves removing the tire to be retreaded 200 from the multidimensional drum 100. As with the fourth step of the process of The invention, the removal of the tire to be retreaded 200 can be done manually by an operator or automatically using Cartesian or multi-articulated robots equipped with grippers allowing to grasp said tire to be retreaded 200.

[0117] The removal of the tire to be retreaded 200 can be done, for example, directly to downstream retreading machines or to storage areas for tires to be retreaded 200. In some workshops and as for the first step of the process of the invention, the removal of the tire to be retreaded 200 can be done using, for example, conveyors, manual or automatic guided vehicle (AGV) trolleys allowing the tire to be retreaded 200 to be transported to, for example, downstream retreading machines or to storage areas.

[0118] Preferably, the pressure P is at least equal to 1 bar and at most equal to 1.5 bar.

[0119] Preferably, the support pressure Pb is at least equal to 3 bars and at most equal to at 8 bars and more preferably at least equal to 4 bars and at most equal to 7 bars.

[0120] Based on the method described above, it would be easy for a person skilled in the art to adapt said method to any other method requiring the use of a multidimensional drum as described in the present invention. By way of example, the method of the invention could be adapted to deconstruction processes requiring the gripping and rotation of a worn tire in order to recover the rubber and metal components.

Claims

1. Demands Multidimensional drum (100) for holding a tire to be retreaded (200) comprising: -a hub (1) with a rotation axis (XX') and intended to support the multidimensional drum (100), -at least two plurality of segments (2), each plurality of segments (2) being axially offset from one another, each plurality of segments (2) comprising segments (3) distributed circumferentially along a circumferential direction (YY') tangent to the multidimensional drum (100), each segment (3) being radially movable, along a radial direction (ZZ') perpendicular to the axis of rotation (XX'), each segment (3) having an external surface (4), the set of external surfaces (4) forming an external surface (5) of generally cylindrical shape, -at least one plurality of segments (2) forming a first external surface (61) of generally cylindrical shape and variable external diameter and comprising a first shoulder (6) having a variable first shoulder diameter DI, -at least a plurality of segments (2) forming a second outer surface (62) of generally cylindrical shape and variable outer diameter and comprising a second shoulder (7) having a second variable shoulder diameter D2, said second shoulder (7) being distant from the first shoulder (6) by a variable distance Lv, -a sealing membrane (14) extending from the first shoulder (6) to the second shoulder (7), said sealing membrane (14) covering the outer surface (5), said sealing membrane (14) being radially and axially deformable, said sealing membrane (14) comprising first and second rings (31, 32) of thickness Ea, said first ring (31) cooperating with the first shoulder (6) to form a first retaining zone (8) intended to receive a first bead (10) of the tire to be retreaded (200), said second ring (32) cooperating with the second shoulder (7) to form a second retaining zone (9) intended to receive a second bead (11) of the tire to be retreaded (200), said first and

2.

3.

4.

5. second holding zones (8, 9) having respectively first and second cylindrical surfaces (11, 12) of variable diameter Dv, -at least one radial displacement means (17) allowing the variable diameters Dv to be varied, -a pneumatic system (15) for inflating a sealed chamber (16), said sealed chamber (16) being formed by the tire to be retreaded (200) and by the sealing membrane (14), said multidimensional drum being characterized in that at least a plurality of segments (2) comprising a first or a second shoulder (6, 7) is axially mobile and in that at least one axial displacement means (18) allows to axially move the at least a plurality of segments (2) comprising a first or a second shoulder (6, 7) to adjust the variable distance Lv. Multidimensional drum (100) according to claim 1 in which the sealing membrane (14) has a hardness of at least 50 shore A and at most 60 shore A. A multidimensional drum (100) according to any one of claims 1 or 2, wherein the thickness Ea of the first and second rings (31, 32) is at least 10 mm and at most 20 mm. A multidimensional drum (100) according to any one of claims 1 to 3, wherein the axial displacement means (18) is driven by an electric, pneumatic, hydraulic, or electromagnetic actuator. A multidimensional drum (100) according to any one of claims 1 to 4, wherein the axial displacement means (18) comprises: - at least one flange (19) connected to each segment (3) of a plurality of segments (2) comprising a first or second shoulder (6, 7), the connection to each segment (3) of a plurality of segments (2) being achieved by means of a radial sliding joint (20), said at least one flange (19) having a thread (21) concentric with the axis of rotation XX', - a circular spindle (23) having an external thread (22) concentric with the axis of rotation XX' and intended to cooperate with the thread (21) of the at least one flange (19), - a brake (24) for locking the circular spindle (23) in rotation when the entire multidimensional drum (100) including the flange (19) is rotated, the rotation of the flange (19) carried out simultaneously with the blocking of the circular spindle (23) generating an axial displacement of the at least one flange (19) and of the plurality of segments (2) connected to the at least one flange (19).

6. Multidimensional drum (100) according to any one of claims 1 to 5 in which the plurality of segments (2) comprising the first shoulder (6) and the plurality of segments (2) comprising the second shoulder (7) are both axially movable.

7. Multidimensional drum (100) according to claim 6 wherein at least one synchronization means (25) permits axial displacement of the plurality of segments (2) comprising the first shoulder (6) in a direction opposite to the direction of axial displacement of the plurality of segments (2) comprising the second shoulder (7), the axial displacement of the plurality of segments (2) comprising the first shoulder (6) and the axial displacement of the plurality of segments (2) comprising the second shoulder (7) occurring at the same linear speed.

8. Multidimensional drum (100) according to claim 7 wherein the synchronization means (25) is of the mechanical, hydraulic or electrical type.

9. Multidimensional drum (100) according to any one of claims 1 to 8 in which three pluralities of segments (2) are radially mobile and cooperate to form the outer surface (5) and in which: -a first plurality of segments (51) is axially mobile and includes the first shoulder (6) cooperating with the outer surface (5) to form the first retaining zone (8) intended to receive the first bead (10) of the tire to be retreaded (200), -a second plurality of segments (52) is axially mobile and includes the second shoulder (7) cooperating with the outer surface (5) to form the second retaining zone (9) intended to receive the second bead (11) of the tire to be retreaded (200), -a third plurality of segments (53) is axially interposed between the first and second pluralities of segments (51, 52), said third plurality of segments 53 being axially fixed.

10. Multidimensional drum (100) according to any one of claims 1 to 9 wherein the radial displacement means (17) is a pneumatic, hydraulic, electrical or electromagnetic system.

11. Multidimensional drum (100) according to claim 10 in which the radial displacement system (17) comprises: - a movable part (26) having a conical outer surface (27), said conical outer surface (27) having a cone axis which is concentric with the axis of rotation XX', said movable part (26) performing a displacement in an axial direction, - a plurality of movable sectors (28) distributed circumferentially in a circumferential direction YY', each movable sector (28) being able to move radially, each segment (3) being connected via an axial sliding joint (29) to at least one movable sector (28), each movable sector (28) having an inclined surface (30) cooperating with the conical outer surface (27) to allow the transmission of an identical radial movement to each segment (3),the radial movement can be an extension or retraction movement depending on the direction of the axial movement performed by the moving part (26).

12. Multidimensional drum (100) according to claim 11 in which the inclined surface (30) of the movable sectors (28) cooperates with the conical outer surface (27) by a sliding connection.

13. Multidimensional drum (100) according to claim 11 in which the inclined surface (30) of the movable sectors (28) cooperates with the conical outer surface (27) by a contact link, the radial retraction of the movable sectors (28) being achieved thanks to the elasticity of the sealing membrane (14) pressing radially on the segments (3) of the different pluralities of segments (2).

14. A retreading method using the multidimensional drum (100) according to claims 1 to 13, characterized in that it comprises the following steps: - conveying the tires to be retreaded 200, said tires to be retreaded 200 being able to be of different types and sizes, - determining a bead diameter Db and a distance between the beads Lb of a tire to be retreaded (200), - activating the axial displacement means (18) to perform an axial extension movement until the variable distance Lv is greater than the distance between the beads Lb, -activation of the radial displacement means (17) to perform a radial retraction movement until the first and second shoulder diameters (D1, D2) are smaller than the diameters of the first and second beads (10, 11) of the tire to be retreaded (200), -placement of the tire to be retreaded (200) on the multidimensional drum (100), the axis of rotation of the tire to be retreaded (200) being substantially parallel to the axis of rotation XX', the first and second beads (10, 11) resting on the sealing membrane (14), -activation of the axial displacement means (18) to achieve an axial retraction movement of the multidimensional drum (100) until the variable distance Lv is equal to the distance between the ridges Lb, -activation of the radial displacement means (17) to achieve a radial extension movement of the diameter Dv until the first and second beads (10, 11) press on the sealing membrane (14) with a pressure Pb, -activation of the pneumatic system (15) to inject air into the sealed chamber (16) to inflate the tire to be retreaded (200) to a pressure P, - rotation of the multidimensional drum (100) to perform the retreading work on the tire to be retreaded (200), - activation of the pneumatic system (15) to remove some of the air contained in the sealed chamber (16) to deflate the tire to be retreaded (200), -activation of the axial displacement means (18) to achieve an axial retraction movement of the multidimensional drum (100) to obtain a variable distance Lv less than the distance between the ridges Lb, -activation of the radial displacement means (17) to achieve a radial retraction movement of the multidimensional drum (100) until the first and second shoulder diameters (D1, D2) are less than the diameters of the first and second bead (10, 11) of the tire to be retreaded (200), -evacuation of the tire to be retreaded (200) from the multidimensional drum (100).

15. Retreading method according to claim 14 wherein the pressure P is at least equal to 1 bar and at most equal to 1.5 bar.

16. Retreading method according to any one of claims 14 or 15 wherein the support pressure Pb is at least equal to 3 bars and at most equal to 8 bars and more preferably at least equal to 4 bars and at most equal to 7 bars.

Images