Method for recovering the material making up the outer layer of a tyre by radially hollowing out the equatorial region of the tyre and then axially machining the hemispheres of the tyre

Abstract

The present invention relates to a method for machining a tyre (1) having a wall (3) comprising at least one outer layer (4) made of an elastomer and at least one reinforcing ply (5) located beneath the outer layer (4) containing a plurality of reinforcing wires (6), the method comprising a step of hollowing out a trench (27) in the equatorial region of the tyre, followed by a material removal step during which a first cutting sequence is performed from the trench (27) in the first hemisphere (H1) of the tyre, and a second cutting sequence is then performed in the second hemisphere of the tyre (H2), to remove material from the outer layer (4).

Description

METHOD FOR RECOVERING THE CONSTITUENT MATERIAL OF THE OUTER LAYER OF A BANDAGE BY RADIAL EXCAVATION OF THE EQUATORIAL ZONE OF THE BANDAGE FOLLOWED BY AXIAL MACHINING OF THE HEMISPHERES OF SAID BANDAGE

[0001] The present invention relates to the field of machining of tires, in particular pneumatic tires based on rubber, which have a wall which includes at least one outer layer based on elastomer and at least one reinforcing layer which is located under said outer layer and which contains a plurality of reinforcing threads, the machining operation having as its purpose the removal from the tire of at least a part of the material constituting the outer layer, for example in order to retread said tire or to recycle said material.

[0002] More specifically, with a view to increasing the recycling rate of the raw materials that make up the tires, the inventors wanted to develop a versatile machining process that would allow the recovery, from a tire that has definitively reached the end of its life and whose casing can therefore no longer be repaired or reused, of the largest possible quantity of rubber-based material constituting the tread of the tire, regardless of the origin of the tire, and without risk of causing the reinforcing wires to break off, which could damage the machining installation or compromise the machining process.

[0003] The objects assigned to the invention are achieved by means of a method for machining a bandage, said bandage having a wall which comprises at least one outer layer based on elastomer and at least one reinforcing layer which is located under said outer layer and which contains a plurality of reinforcing threads, said method being characterized in that it comprises: - a trenching step, during which the tire is fixed to a rotating support having an axis of rotation called the "main axis", and by means of said support the tire is rotated about itself, around said main axis, in a chosen direction of rotation, a cutting tool is positioned opposite the tire at an axial abscissa within an axial range called the "equatorial zone" which, on the one hand, represents less than 35% of the axial range covered by the tire, preferably less than 30% of the range axial covered by the bandage, more preferably less than 25% of the axial area covered by the bandage, or even less than 20%, less than 15% or even less than 10% of the axial area covered by the bandage, and which on the other hand contains the fictitious plane called the "equatorial plane" which is normal to the main axis and which passes through the middle of the axial area occupied by the bandage, said equatorial plane thus dividing the bandage into a first hemisphere and a second hemisphere, then, while the bandage is driven in rotation around the main axis, the cutting tool is engaged in the inner layer, according to a centripetal radial penetration movement directed towards the reinforcement layer, so as to dig in the outer layer a circumferential trench located at the chosen axial abscissa, in the equatorial zone; - then a material removal step during which a first cutting sequence is executed in which the bandage is rotated on itself, around the main axis, in a chosen direction of rotation, and a cutting tool is made to follow a first cutting path in which said cutting tool travels axially through the first hemisphere, from the trench, in order to remove material from the outer layer in said first hemisphere, and a second cutting sequence in which the bandage is rotated on itself, around the main axis, in a chosen direction of rotation, and a cutting tool is made to follow a second cutting path in which said cutting tool travels axially through the second hemisphere, from the trench, in order to remove material from the outer layer in said second hemisphere.

[0004] The fact of engaging the tire, and more particularly the tread, in the equatorial zone, by digging, through a dressing operation in which the cutting tool progresses radially in the outer layer, an equatorial trench which will then serve as a starting point for carriage operations, in which the cutting tool progresses this time axially in the outer layer, to cover the hemisphere concerned, has several advantages.

[0005] Firstly, in the equatorial zone, the reinforcing threads are relatively invulnerable to tearing, and the reinforcing web is relatively invulnerable to perforation, because on the one hand the bandage exhibits, in said equatorial zone, a relative flexibility in bending, which allows the reinforcing threads to bend elastically under the stress of the tool, and on the other the portions of the reinforcing wires which are in the equatorial zone are still held firmly against tearing by the constituent material of the outer layer which temporarily remains on either side of the trench, and are located axially away from the lateral edges of the reinforcing layer, and therefore away from the free ends of the reinforcing wires, which form points more vulnerable to peeling than the said central portions of the said reinforcing wires.

[0006] Next, since in the vast majority or even all cases the equatorial zone contains the radially outermost ridge line of the bandage wall, and more particularly the ridge line of the reinforcement layer where the reinforcing threads reach their radially outermost position, while the shoulders, and more particularly the portions of the reinforcing layer located in the shoulders, are generally closer radially to the axis of the bandage than the ridge line located in the equatorial zone, an approach via the equatorial zone allows us to take a reference on said ridge line, and thus to define suitable cutting trajectories, which will not risk perforating the reinforcing layer or tearing the reinforcing threads.

[0007] Furthermore, a starting point for the cutting path from inside a trench dug in the equatorial zone allows the cutting tool to grip, at the starting point of the cutting path, a relatively thick layer of material, which corresponds to the side of the trench, and is relatively rigid, since it is supported, against the axial advance force of the cutting tool, by the entire outer layer that still remains in the hemisphere concerned, so that an effective cut can be obtained, since the material does not evade the action of the cutting tool, unlike what might possibly happen if the bandage were approached laterally by a shoulder, in an area where the outer layer would be thinner and / or rounded.

[0008] Finally, the trench allows, if necessary, the implementation of two separate cutting tools, each responsible for machining one hemisphere, in masked time relative to the other, each starting from the inside of the same trench, and axially from the same starting point located in the equatorial zone, which reduces the cycle time and therefore increases efficiency.

[0009] Other objects, features and advantages of the invention will become apparent in more detail from the following description, as well as from the accompanying drawings, which are provided for illustrative purposes only and are not intended to be limiting, including:

[0010] Figure 1 illustrates, from a perspective view, an example of an installation for implementing a process according to the invention, here more particularly an installation comprising two robotic arms carrying respectively a first cutting tool and a second cutting tool arranged on either side of the rotating support which carries the band to be machined, and each dedicated to the machining of a distinct hemisphere.

[0011] Figure 2 is a front view of the installation in Figure 1, in a plane normal to the main axis.

[0012] Figure 3 illustrates, according to a schematic cutaway perspective view, an example of a bandage carcass. The said bandage includes here, by way of non-limiting example, a first reinforcement layer, radially the outermost, which has a first set of reinforcing wires arranged parallel to each other, according to a first oblique orientation with respect to the equatorial circumferential direction of the bandage, and a second reinforcement layer, radially more internal than the first reinforcement layer, which is partially covered by the first reinforcement layer and which extends axially beyond the axial limits of the first reinforcement layer, and which includes a second set of reinforcing wires, arranged parallel to each other, and having a second oblique orientation of the same sign as the first orientation of the reinforcing wires of the first reinforcement layer.

[0013] Figure 4 is a cross-sectional view, in a radial plane containing the principal axis, and before any material removal operation, of the bandage of Figure 3.

[0014] Figures 5A and 5B illustrate, in schematic perspective and radial cross-sectional views respectively, the bandage of Figure 4 subjected to a trenching step according to the invention, during which a circumferential trench is excavated in the equatorial region of said bandage. Here, the trenching exposes the first reinforcement layer at the bottom of said trench, thus allowing identification of the orientation of the reinforcing wires of the first reinforcement layer, as well as the radial distance, referred to as the "radial envelope distance," at which it is located, relative to the axis main support, the radially external limit of the reinforcing wires of the reinforcing layer which lies immediately below the outer layer.

[0015] Figures 6A, 6B and 6C illustrate, respectively according to a partial schematic view from above, a perspective view, and a schematic cross-sectional view in a radial plane, the bandage of Figures 4 and 5A and 5B, after a first cutting sequence during which the bandage was rotated in a first direction of rotation and the outer layer was removed by axially moving a cutting tool, in contact with the first reinforcement layer and then the second reinforcement layer, from the equatorial trench towards a first axial end of the bandage, on a first axial cutting area which covers a first hemisphere of the bandage.

[0016] Figures 7A and 7B illustrate, respectively in a schematic partial top view and a schematic radial cross-sectional view, the bandage of Figures 4 and 5A and 5B, after a second cutting sequence which followed the first cutting sequence of Figures 6A, 6B and 6C, and during which the outer layer was removed by rotating the bandage in a second direction of rotation, opposite to the first direction of rotation, and by axially moving a second cutting tool, distinct from the first cutting tool used for the first cutting sequence, in contact with the first reinforcement layer and then the second reinforcement layer, from the equatorial trench towards the second axial end of the bandage, on a second axial cutting area which covers the second hemisphere of the bandage.

[0017] Figures 8A and 8B illustrate, respectively in a schematic partial top view and a schematic radial cross-sectional view, the bandage of Figures 4 and 5A and 5B, after a variant of the second cutting sequence, which was preferably performed simultaneously with the first cutting sequence of Figures 6A, 6B, and 6C. During this variant of the second cutting sequence, the outer layer is removed in the second hemisphere of the bandage, maintaining the same first direction of rotation of the bandage as that used for the first cutting sequence to remove the outer layer in the first hemisphere of the bandage, and moving axially a second cutting tool, distinct from the first cutting tool used for the first cutting sequence, in the axial range corresponding to said second hemisphere, towards the second axial end of the bandage, but maintaining said second cutting tool over at least part or even all of the second hemisphere, at a radial distance from the main axis which is strictly greater than that used for the first cutting tool in the first hemisphere of the bandage, in order to retain in the second hemisphere, for safety, a residual thickness of outer layer which protects the reinforcing threads from tearing.

[0018] Figure 9 illustrates, in a detailed perspective view, the end of a robotic arm of the installation of Figures 1 and 2 which carries a cutting tool formed by a rotating cylindrical knife as well as the sharpening system for maintaining the circular edge of said knife.

[0019] Figure 10 illustrates, in a schematic view in a radial plane, the principle by which, to ensure that the cutting tool comes into contact with the reinforcing layer and then slides along the layer while remaining in contact with the reinforcing wires, in order to remove as much thickness as possible from the outer layer, the cutting tool is brought to a starting position, here in the equatorial plane, which is radially closer to the principal axis by a value called the "nominal deflection value," than the reinforcing layer, whose outermost face, in the absence of a cutting tool, is located at a radial distance from the principal axis called the "radial envelope distance." Thus, the cutting tool is advantageously pre-stressed against the reinforcing layer by locally creating a slight centripetal radial deformation of the reinforcing wires through elastic bending.

[0020] The present invention relates to a method for machining a tire 1.

[0021] The machining process according to the invention can be used for example for the stripping of a tire 1, that is to say for removing from the tire the remains of a used tread, with a view to retreading said tire, when the carcass of said tire 1 is reusable.

[0022] However, preferably, the machining process according to the invention will be part of a process for recycling a rubber-based material present on the tire 1, preferably a process for recycling the rubber-based material constituting the tread, and will therefore aim to recover the largest possible quantity of said material relative to the total quantity of said material that is present on said tire 1.

[0023] Such a recycling process will be particularly applicable to end-of-life bandages, whose casing can no longer be repaired or reused, and which must therefore be dismantled to recover the raw materials.

[0024] As can be seen in particular in Figures 4, 5B, 6C and 10, the bandage 1 has a wall 3 which includes at least one outer layer 4 based on elastomer and at least one reinforcing layer 5 which is located under said outer layer 4 and which contains a plurality of reinforcing threads 6.

[0025] We will denote E4 the thickness of the outer layer 4, and in particular the residual thickness of said outer layer, which separates the outer surface of the wall 3 from the surface of the reinforcement layer 5, 5' closest to said outer surface of the wall 3.

[0026] In a manner known per se, the reinforcing layer 5, 5' is preferably formed by a thin layer of a matrix-forming material which extends along two principal directions which define the surface of the reinforcing layer, and in the thickness of which the reinforcing wires 6, 6' are embedded.

[0027] In particular, we may have a 5, 5' reinforcing layer whose matrix is ​​formed on the basis of elastomer, preferably on the basis of rubber, and containing reinforcing wires 6 metallic, or possibly in polymer such as aramid.

[0028] Alternatively, the reinforcement layer 5, 5' may have a resin matrix reinforced by fiberglass reinforcing threads 6, 6'.

[0029] Within the same reinforcement layer 5, 5', the reinforcement wires 6, 6' will preferably be arranged side by side, parallel to each other, although other arrangements are conceivable without going out of the scope of the invention.

[0030] The said reinforcing wires 6, 6' are arranged according to an implantation scheme, which is specific to bandage 1.

[0031] The layout diagram defines the path of the reinforcing wires 6, 6' within the reinforcing layer 5, 5', and therefore in particular the orientation A6, A6' of said reinforcing wires 6, 6', or the spacing between neighboring reinforcing wires 6, 6'.

[0032] As an example, we can consider a first layout scheme, as illustrated in Figures 3, 4 and 7A, which in this case includes a first reinforcement layer 5, radially the outermost, which has a first set of reinforcing wires 6, called "first reinforcing wires 6", arranged parallel to each other, according to a first orientation A6 oblique to the circumferential equatorial direction of the bandage 1, and a second reinforcing layer 5', radially more internal than the first reinforcing layer 5, which is partially covered by the first reinforcing layer 5 and which extends axially beyond the axial limits, or "edges" 51, 52, of the first reinforcing layer 5, and which includes a second set of reinforcing wires 6', called "second reinforcing wires 6'", arranged parallel to each other, and having a second oblique orientation A6', forming here an angle Aô'ang on figure 6A, second orientation A6' which is of the same sign as the first orientation A6 of the reinforcing wires 6 of the first reinforcing layer 5.We note 5' 1 and 5'_2 the axial ends, or "edges", of the second reinforcement layer 5'.

[0033] Such an initial layout scheme may be frequently found within a tire 1 intended for heavy goods vehicles.

[0034] The first reinforcing wires 6 of the first reinforcing layer 5, installed according to this first layout, will preferably be metallic. Similarly, the second reinforcing wires 6' of the second reinforcing layer 5', installed according to this first layout, will preferably be metallic.

[0035] Of course, the invention is applicable to other types of reinforcement wire layout schemes.

[0036] For the sake of convenience of description, when it is not necessary to distinguish specifically between the first reinforcing layer 5 and the second reinforcing layer 5', respectively between the first reinforcing wires 6 and the second reinforcing wires 6', and in particular when characteristics can apply indifferently to a bandage 1 in which only one reinforcing layer would be concerned by the machining operation or to a bandage in which several reinforcing layers would be concerned by the machining operation, one may refer generically to a "reinforcing layer 5, 5'" or to a "reinforcing layer 5", and respectively to "reinforcing wires 6, 6'" or "reinforcing wires 6".

[0037] Furthermore, it should be noted that the invention is applicable to a wide variety of types of tires, including toroidal tires intended for use on vehicle wheels, among These include pneumatic tires, or airless tires suspended by flexible spokes, as well as tires forming tracks intended, for example, for construction equipment, agricultural machinery, or snowmobiles, or even tires forming reinforced belts such as transmission belts or conveyor belts. The support 20, designed to receive the tire 1 for machining operations, can of course be adapted according to the type of tire 1 being processed.

[0038] Preferably, the process can be applied to tires 1 intended for heavy goods vehicles, typically vehicles whose total authorized weight exceeds 3.5 tonnes, said tires being sized to be mounted on rims with dimensions between 16.5 inches and 24 inches.

[0039] The process can also be applied to tires 1 intended for passenger vehicles, and therefore adapted to rims with a diameter between 13 inches and 24 inches.

[0040] The method according to the invention can of course be applied without restriction to tires of very varied dimensions, including very large tires, for example civil engineering tires intended to be mounted on rims up to 63 inches.

[0041] Preferably, in a manner known per se, and as can be seen in particular in figures 1, 2 and 4, the bandage 1 has a first annular heel 7 and a second annular heel 8, provided respectively with a first rod and a second rod (not shown), and the wall 3 of the bandage forms a radially external apex 10, as well as a first flank 11 which connects said apex 10 to the first heel 7 and a second flank 12 which connects the apex 10 to the second heel 8.

[0042] As is known in itself, the first and second heels 7, 8 allow the mounting of the tire onto a rim.

[0043] The outer layer 4 will preferentially correspond to the tread of the tire 1, which extends over the top 10 of said tire 1.

[0044] Preferably, wall 3 of the bandage has a toroidal shape of revolution, convex outwards, and can more preferably delimit in this way, in the case where bandage 1 is a pneumatic bandage, an inflation cavity which allows the inflation gas of said pneumatic bandage to be contained.

[0045] According to the invention, the method includes a trenching step, during which the tire 1 is fixed on a rotating support 20 having an axis of rotation called the "main axis" Z20, and by means of said support 20 the tire 1 is driven in rotation about itself, around said main axis Z20, in a chosen direction of rotation R20+, R20-, a cutting tool 2 is positioned opposite the tire 1 at an axial abscissa included in an axial range called the "equatorial zone", then, while the tire 1 is driven in rotation R20 around the main axis Z20, the cutting tool 2 is engaged in the inner layer 4, according to a centripetal radial penetration movement directed towards the reinforcement layer 5, so as to dig in the outer layer 4 a circumferential trench 27 located at the chosen axial abscissa, in the equatorial zone.

[0046] Preferably, the rotating support 20 is arranged to hold the bandage 1, preferably in a non-inflated state, by the first heel 7 and second heel 8, while leaving the top 10 free, and more particularly free to deform elastically under the pressure of the cutting tool 2.

[0047] The inventors have indeed found that it was thus possible to hold the bandage 1 by the heels 7, 8, while maintaining sufficient firmness of said bandage 1 for the machining operation, without it being necessary to inflate said bandage 1 or to support said bandage 1 by tiles which would come to be placed under the top 10 of said bandage 1.

[0048] It is therefore advantageous to machine bandages 1 which are no longer waterproof, because they have perforations or lacerations, which is common on bandages that have reached the end of their life.

[0049] Preferably, the process, and more particularly the material removal step, will therefore be carried out on an uninflated bandage 1, that is to say a bandage 1 whose radially internal face of the wall 3 is at ambient atmospheric pressure, without overpressure relative to said ambient atmospheric pressure which bathes the support 20 and more generally the workshop in which the installation 40 which allows the process to be carried out is located.

[0050] In addition, the support by the heels 7, 8 allows the same support 20 to easily adapt to bandages 1 of very varied dimensions, and in particular to bandages 1 with very different internal diameters from one bandage 1 to another.

[0051] In this respect, it should be noted that, as illustrated in Figures 1 and 2, the rotary drive support 20 can, for example, be formed by a radially expanding drum 21, having jaws 22 which are able to alternately expand radially centrifugally to engage with the heels 7, 8, thus adopting a diameter corresponding to the internal diameter of the band 1, and retract radially centripetally to release the band 1 after the machining operation.

[0052] Here again, the fact that the bandage 1 does not need to be inflated to implement the process according to the invention allows the use of a particularly simple and inexpensive support 20, capable of easily adapting to many dimensions of bandage 1, since it is not necessary to provide on the support 20 means which would ensure a seal of the cavity of the bandage 1, and which would therefore be very dependent on the dimensions of each bandage.

[0053] As a guideline, the rotational speed of the support 20, and therefore of the tire 1, during the trenching 27 and subsequent material removal operations, can be between 1 rpm and 5 rpm, for example, 3 rpm. Higher rotational speeds, such as 10 rpm, could of course be considered. However, the aforementioned speeds offer a favorable compromise between the power required for accelerating and braking the support 20, the reliability of process control, and cycle time.

[0054] In practice, the main axis Z20 will coincide with the central axis of the tire 1, around which the tire 1 forms a toroidal ring, and which therefore corresponds to the axis around which the tire rotates when said tire 1 is in service on a vehicle wheel and rolls on the ground.

[0055] By convention, we will designate as "axial" a direction parallel to the axis considered, here more particularly a direction parallel to the axis of rotation Z20, and as "radial" a direction perpendicular to said axis.

[0056] We will designate by "circumferential" direction a direction of the bandage which is orthoradial with respect to the central axis of the bandage, here therefore orthoradial with respect to the principal axis Z20, that is to say a direction which is contained in a plane normal to the central axis of the bandage and which is, at a point considered of the bandage, perpendicular to the radius which joins the central axis of the bandage to said point considered, or in other words, a direction which, at a point considered of the bandage, is normal to the radial plane which contains the central axis of the bandage and which passes through said point considered.

[0057] We will designate by "radial plane", or "meridian plane", a plane which contains the central axis of the bandage, here therefore which contains the principal axis Z20, and which therefore extends on the one hand along the central axis of the bandage, and on the other hand along a radius of the bandage, perpendicular to the central axis.

[0058] By analogy with the Earth, we will conventionally designate as "equatorial plane" P_EQ the plane which is normal to the central axis of the band, here therefore which is normal to the principal axis Z20, and which passes through the middle of the axial range W1 occupied by the band 1. Said equatorial plane P_EQ thus divides said band 1 into a first hemisphere H1 and a second hemisphere H2, said second hemisphere H2 being located opposite the first hemisphere H1 with respect to said equatorial plane P_EQ.

[0059] The axial width of the band corresponds to the distance that separates two fictitious gauge planes which are normal to the central axis of the band, here the principal axis Z20, and which are each tangent to the wall 3, respectively at a first axially outermost point of the wall 3, generally located on the outer surface of the first flank 11, and forming a first axial end 11 of the band, and at a second axially outermost point of the wall 3, located axially opposite the first point, and generally located on the surface of the second flank 12, and forming a second axial end 12 of the band 1. The axial range occupied by the band 1, which we will denote "W1", will correspond to the portion of the space delimited axially by, and therefore included between, the two aforementioned fictitious gauge planes.

[0060] By convention, the term "equatorial zone" will be defined as an axial area of ​​bandage 1 which, on the one hand, represents less than 35% of the axial area W1 covered by bandage 1, preferably less than 30% of the axial area W1 covered by bandage 1, more preferably less than 25% of the axial area W1 covered by bandage 1, or even less than 20%, less than 15% or even less than 10% of the axial range W1 covered by bandage 1, and which on the other hand contains the equatorial plane P_EQ of the bandage.

[0061] By convention, we will consider that the direction of rotation R20- is negative when it corresponds to a clockwise direction on figures 1 and 2, and is therefore oriented from bottom to top on figures 6A and 8A.

[0062] Conversely, we will consider that the direction of rotation R20+ is positive when it corresponds to an anti-clockwise direction, or narrow tri-gonomic direction, on figures 1 and 2, and is therefore oriented from top to bottom on figure 7A.

[0063] After the trenching stage, the process includes a material removal stage during which the following operations are performed: - a first cutting sequence during which the bandage 1 is rotated on itself, around the main axis Z20, in a chosen direction of rotation R20+, R20-, and a cutting tool 2 is made to follow a first cutting trajectory T2_l according to which said cutting tool 2 travels axially through the first hemisphere Hl, from the trench 27, in order to remove material from the outer layer 4 in said first hemisphere Hl, - and a second cutting sequence during which the bandage (1) is rotated about itself, around the main axis Z20, in a chosen direction of rotation R20+, R20-, and a cutting tool 2, 2' is made to follow a second cutting trajectory T2_2 according to which said cutting tool 2, 2' travels axially through the second hemisphere H2, from the trench 27, in order to remove material from the outer layer 4 in said second hemisphere H2.

[0064] It should be noted that one can consider using one cutting tool 2 or several cutting tools 2, 2', for example two cutting tools 2, 2' as illustrated in figures 1 and 2. When it is not necessary to distinguish specifically between several cutting tools 2, 2', one can therefore refer in the following generically to "a cutting tool 2, 2'" or to "the cutting tool 2, 2'".

[0065] Preferably, the same cutting tool 2, 2' is used to dig trench 27 and then perform the first cutting sequence.

[0066] We denote Kl the starting point of the first cutting trajectory T2_l, Ml the arrival point, and W2_l the axial range, called the "first axial cutting range" W2_l, that the The first cutting path T2_l makes the cutting tool 2 travel along the main axis Z20. In practice, the said first cutting range W2_l here covers the first hemisphere Hl.

[0067] Let K2 be the starting point of the second cutting path, M2 the corresponding ending point, and W2_2 the axial range, called the "second axial cutting range" W2_2, which the second cutting path T2_2 makes the cutting tool travel along 2, 2' along the main axis Z20. In practice, said second cutting range W2_2 covers the second hemisphere H2.

[0068] The "axial path direction" S2_l, S2_2 designates the direction in which the cutting tool 2, 2' considered travels, preferably monotonically, the axial range W2_l, W2_2 during the material removal step, in abscissa along the main axis Z20, and therefore moves over the width of the band, transversely to the circumferential direction of the band 1, starting from a starting axial abscissa, which corresponds to the end of the axial cutting range where the cutting path begins, to arrive at an ending axial abscissa, which corresponds to the other end of the axial cutting range, where the cutting path ends.

[0069] By convention, the axial direction of travel can be considered positive, and therefore the cutting tool can be considered to move along increasing abscissas along the principal axis Z20, when the cutting tool moves from the second flank 12 to the first flank 11. This corresponds to a direction of movement from the background to the foreground in Figures 1 and 2, and from left to right in Figures 6A and 8B. For convenience, the positive direction of increasing abscissas of the principal axis Z20 can be denoted Z20+.

[0070] Advantageously, by digging trench 27, in the equatorial zone, and more preferentially at an axial abscissa which coincides with the abscissa of the equatorial plane P_EQ, we attack the bandage 1 by its crest line, and in an area where the reinforcing wires 6 are the least vulnerable to tearing, which secures the cutting operations, both during the digging of trench 27 and during the execution of subsequent cutting sequences.

[0071] The equatorial plane P_EQ can be located by any appropriate means, for example using a tool for measuring the width of the band 1 associated with the support 20 or to the handling system which brings and places the bandage 1 on the support 20. The measuring tool may be optical, or it may use one or more mechanical probes which come into contact with the sides 11, 12.

[0072] Advantageously, the material extracted from the outer layer 4 during the digging of the trench 27 can be advantageously recovered, in the same way as the material which will then be taken during the execution of the first and second cutting trajectories T2_1, T2_2, and can even represent up to 30% or even 35% of the total material recovered by the process according to the invention.

[0073] Furthermore, by fixing the starting points Kl, K2 in the trench 27, and therefore in the equatorial zone, we allow the cutting tool 2 or the cutting tools 2, 2' to be pre-positioned from the outset at the appropriate axial abscissa, and at the appropriate depth of cut, and to effectively attack the outer layer 4, during their respective axial movements in the hemispheres Hl, H2.

[0074] By convention, we can consider that the axial position of the cutting tool 2, and more particularly the axial position of the starting point Kl, K2 of the cutting trajectory T2_l, T2_2, corresponds to the axial position of a reference point which belongs to the cutting tool 2, which corresponds to the point of the cutting edge of the cutting tool 2 which is in contact with the wall 3 of the band, in particular with the reinforcement layer 5, at the instant considered, and which is radially closest to the main axis Z20 (in particular if several points of the cutting tool are in contact with the wall 3 of the band 1).

[0075] Preferably, during the trenching stage, the outer layer 4 is excavated until the bottom of the trench 27 reaches the reinforcement layer 5, as illustrated in Figures 5A and 5B.

[0076] Advantageously, this makes the reinforcing wires 6, 6' visible in the bottom of trench 27.

[0077] This advantageously allows the orientation A6 of the reinforcing wires 6 to be identified by observing the apparent surface of the reinforcing layer 5, which forms the bottom of the trench 27. This identification is preferably carried out automatically, by means of an optical detection device 50, such as a profilometer or a camera associated with a system of image processing, capable of capturing the undulating reliefs created by the reinforcing wires 6, and determining their orientation A6.

[0078] The fact of radially excavating the outer layer 4 down to the reinforcing layer 5 also makes it possible to identify, for example by means of a laser rangefinder which belongs to the optical detection device 50 and which is pointed at the bottom of the trench 27 in a reference angular sector which is distant from the working angular sector in which the cutting tool 2 presses against the wall 3, the radial distance, called the "radial envelope distance" D0_ply, at which, with respect to the main axis Z20, in the absence of radial stress exerted on the wall 3 by a cutting tool 2, 2', lies the radially external limit of the reinforcing wires 6 of the reinforcing layer 5 which is immediately under the outer layer 4.

[0079] This radial envelope distance D0_ply advantageously constitutes a possible reference for defining the cutting trajectories T2_l, T2_2.

[0080] Preferably, the first cutting sequence is executed by bringing the cutting tool 2 into contact with the reinforcing layer 5 and then axially moving the cutting tool 2 by sliding the first cutting tool 2 in contact with the reinforcing layer 5, along the reinforcing wires 6, in the first hemisphere Hl.

[0081] This maximizes the thickness, and therefore the quantity, of material recovered, as can be seen in particular in figures 6A, 6B and 6C.

[0082] The cutting tool 2 may remain in contact with the reinforcement layer 5, and where appropriate successively in contact with the first reinforcement layer 5 and then with the second underlying reinforcement layer 5' which extends axially beyond the edge 5 1 of the first reinforcement layer 5, over at least part, or even over all, of the axial area occupied by the first hemisphere HL. The cutting tool may thus in particular be in contact with the reinforcement layer 5, 5' when it crosses, in its axial movement, in the direction of travel S2_l, the edge 5 1 of the first reinforcement layer 5, and where appropriate the edge 5' 1 of the second reinforcement layer 5'.

[0083] Of course, precautions must then be taken to prevent the cutting tool 2 from accidentally catching, lifting, or tearing the reinforcing wires 6, 6', particularly when the cutting tool reaches an axial end of a layer of reinforcement 5, 5', that is to say a selvage 5 1, 5' 1, at the level of which the reinforcing threads 6, 6' have a free end, and therefore form points potentially vulnerable to peeling.

[0084] Therefore, preferably, when the reinforcing wires 6 have an oblique orientation A6 with respect to the equatorial plane P_EQ and are interrupted at the level of a first edge 51 of the reinforcing sheet 5, which first edge 51 is located in the first hemisphere H1 at an axial distance from the equatorial plane P_EQ, the first cutting sequence is adapted such that, as illustrated in Figure 6A, the relative displacement V2 of the cutting tool 2 with respect to the reinforcing sheet 5 has: - on the one hand, a circumferential displacement component V2_circ, induced by the rotation R20 of the bandage, which has the same sign as the circumferential component Aô circ of the orientation A6 of the reinforcing wires, considered when traversing said reinforcing wires 6 from the equatorial plane P_EQ towards the first edge 5 1 of the reinforcing layer 5, - and on the other hand an axial displacement component V2_ax, which corresponds to the direction in which the cutting tool 2 traverses axially the first hemisphere Hl, which axial displacement component V2_ax has the same sign as the axial component A6_ax of the orientation A6 of the reinforcing wires 6, considered when traversing said reinforcing wires 6 from the equatorial plane P_EQ towards the first edge 5 1 of the reinforcing sheet.

[0085] Thus, if we consider at a given instant, in a plane frame whose origin corresponds to the point of contact of the cutting tool 2, and more particularly of the cutting edge of the cutting tool 2, with the reinforcing sheet 5, and more particularly with a reinforcing wire 6, at the instant considered, and whose base is defined by an axial vector, parallel to the principal axis Z20, and a circumferential vector, perpendicular to the axial vector, then the velocity vector V2 of the cutting tool 2 which characterizes, at the point of contact between the cutting tool 2 and the reinforcing sheet 5, the displacement of the cutting tool 2 with respect to the surface of the reinforcing sheet 5, is located in the same quadrant of said frame as the direction vector tangent to the reinforcing wire 6 passing through the origin of the frame at the instant considered, for example in the Southeast quadrant in Figure 6A, and points in the same direction as said direction vector tangent to the reinforcing wire 6,for example, to the right and downwards in figure 6A.

[0086] More specifically, the invention will allow, through a judicious choice of cutting parameters, and more particularly through a judicious selection of the hemisphere and therefore of the axial direction of travel S2_l, as well as the direction of rotation R20+, R20-, taking into account the identified orientation A6 of the reinforcing wires 6, to ensure that the circumferential components V2_circ and respectively axial V2_ax of the velocity vector V2 representing the displacement of the cutting tool 2 with respect to the reinforcing layer 5 are, at the moment when said cutting tool 2 crosses axially the axial end 5 1 of the reinforcing layer 5 located in the hemisphere considered, and therefore crosses the free ends of the reinforcing wires 6, of the same signs as the circumferential components Aô circ, respectively axial A6_ax, of the direction vector, tangent to the reinforcing wires 6, which characterizes the orientation A6 of said reinforcing wires at the axial end 5 1 of said reinforcing layer 5.

[0087] The invention will therefore make it possible to avoid cutting against the grain of the reinforcing wires 6, 6', and more particularly the extremity points formed by said reinforcing wires 6, 6' at the selvedges 5 1, 5' 1 of the reinforcing layers 5, 5'. On the contrary, the cutting tool 2 will advantageously circulate in a direction which tends to press against the reinforcing layer 5, 5' and the carcass of the bandage the points formed by the ends of said reinforcing wires 6, 6' at the level of the selvedge(s) 5 1, 5' 1 of the reinforcing layer(s) 5, 5' concerned.

[0088] It should be noted that if the direction of rotation R20+, R20- is imposed for the first cutting sequence, for example if, for energy saving, it is not desired to stop the rotation R20 of the bandage completely, nor even more so to reverse the direction of rotation R20+, R20- of the bandage, in the transitional period which separates the completion of the trenching step 27 from the execution of the first cutting sequence, then it will be possible to select, for the execution of the first cutting sequence, the hemisphere which is appropriate in consideration of the direction of rotation R20+, R20- and the identified orientation A6 of the reinforcing wires 6, so that the tool 2 works in the right direction in said hemisphere.

[0089] It should be noted in this regard that, following the digging of trench 27 and during the acquisition, here by the optical detection device 50, of information relating to the orientation A6 of the reinforcing wires and the radial distance of the envelope D0_ply, it will be possible to maintain the bandage 1 in rotation R20, at its nominal speed used for cutting operations, typically between 1 rev / second and 5 rev / second, for example equal to 3 rev / second as indicated above, if the performance of the optical detection device 50 allows it, or by slowing down the support, for example to go down to a speed between 0.5 rev / second and 1 rev / second.

[0090] To ensure that the cutting tool 2 is brought into contact with the reinforcing layer 5, it is preferable to radially pre-stress the cutting tool 2 against said reinforcing layer 5.

[0091] As such, the process preferably includes: - a bandage analysis step during which the radial distance known as the "radial envelope distance" D0_ply is evaluated, preferably by detecting an arrival of the trench 27 at the reinforcement layer 5, at which, with respect to the main axis Z20, in the absence of radial stress exerted on the wall 3 by a cutting tool 2, 2', the radially external limit of the reinforcing wires 6 of the reinforcement layer 5 which is immediately under the external layer 4 is located, - then a cutting path definition step during which the first cutting path T2_l is defined, and preferably also the second cutting path T2_2, from the radial envelope distance D0_ply, by fixing the radial position of the starting point Kl of the first cutting path T2_l, and preferably also the radial position of the starting point K2 of the second cutting path T2_2, at a radial distance from the main axis Z20 which is less than the radial envelope distance D0_ply by a non-zero value called the "nominal deflection value" D bend, as illustrated in Figure 10.

[0092] The said nominal value of deflection D bend is preferably between 1 mm and 5 mm, more preferably between 2 mm and 5 mm, for example equal to 3 mm.

[0093] As illustrated in Figure 10, the application of a nominal deflection value D bend allows the cutting tool 2, 2' to cause a radial indentation of the wall 3 by elastic deformation in centripetal radial bending of the reinforcing wires 6, 6', and thus creates a radial compression prestress of the cutting tool 2 against the outer layer 4 supported by the reinforcing wires 6, 6', which allows the outer layer 4 to be scraped as close as possible to the reinforcing wires 6, 6', and more preferably in contact with said reinforcing wires 6, 6', taking into account where appropriate the degree of sharpness of the cutting tool 2, 2'.

[0094] Such pre-stress also makes it possible to compensate for any defects in centering or roundness of the band 1, and therefore allows the cutting tool 2, 2' to reach the reinforcement layer 5 over the entire circumference of said band 1.

[0095] Advantageously, the starting points Kl, K2 of the cutting trajectories being located in the equatorial zone of the band 1, the nominal value of bend D applies in practice to the radially outermost crest line of the reinforcement layer 5 and the reinforcing wires 6.

[0096] We can generate different types of cutting trajectories T2_l, T2_2, for example straight cutting trajectories parallel to the main axis Z20, allowing the cutting tool 2, 2' to travel its hemisphere Hl, H2 at a constant distance from the main axis Z20, or even curved cutting trajectories, aimed at better following the curvature of the reinforcement layer(s) 5, 5' on the axial width of the band 1.

[0097] According to a preferred implementation possibility, the cutting tool 2 is controlled radially while the said cutting tool 2 is moved axially along the first hemisphere Hl, so as to maintain the cutting tool 2 in sliding contact with the reinforcing sheet 5, along the reinforcing wires 6.

[0098] Such radial force control advantageously allows the cutting tool 2, 2' to remain permanently in contact with the wall 3, and in compression against said wall 3, and more particularly in contact with the reinforcement layer 5, 5', during the rotation R20 of the bandage 1, even in the event of irregularities in curvature or centering causing out-of-roundness, and also allows the cutting tool 2, 2' to automatically accommodate, by dynamically adapting its radial position, the variations in the surface of the reinforcement layer 5, 5', in particular the possible curvature of said reinforcement layer 5, 5' as well as the bumps formed by the edge(s) 51, 5'1 of the reinforcement layer(s) 5, 5' traversed by the cutting tool 2, 2' in the hemisphere considered.

[0099] For example, the cutting tool 2, 2' can be controlled by a radial force so that the cutting tool 2 exerts a constant centripetal radial force against the wall 3, and more particularly against the reinforcement layer 5, 5', while the said cutting tool 2, 2' moves along the main axis Z20.

[0100] The intensity of the radial force may, for example, be chosen to be equal to the intensity which results, at the starting point Kl, K2 of the cutting trajectory, from the sinking of the reinforcement layer 5 under the effect of the forced radial positioning of the tool in application of the nominal value of deflection D bend.

[0101] To achieve radial force control, a pneumatic cylinder can be used, for example, to radially press the cutting tool 2, 2' against the wall 3, and more specifically against the reinforcing layer 5, 5', with the desired radial force intensity. A pneumatic cylinder effectively provides both precise control of the force intensity and a flexible, floating pneumatic suspension of the first cutting tool 2, allowing it to remain constantly in contact with the wall 3, and more specifically with the reinforcing layer 5, 5'.

[0102] According to one possible implementation, the first cutting sequence is executed using a first cutting tool 2, and the second cutting sequence is executed using a second cutting tool 2' distinct from the first cutting tool 2.

[0103] This gives a certain versatility to the installation 40 planned to implement the process, by offering the possibility of optimally treating different types of bandage with very diverse A6, A6' orientations of reinforcing wires, in particular because there is always a possible combination of cutting tool 2, 27 direction of rotation R20+, R20- adapted to the A6, A6' orientation of the 6, 6' reinforcing wires, or by offering the possibility of treating, as the case may be, the two hemispheres H1, H2 sequentially or simultaneously.

[0104] Preferably, it is the same cutting tool 2, here the first cutting tool 2, that is used to dig trench 27 and then to perform the first cutting sequence.

[0105] According to one possible implementation, the first cutting sequence and the second cutting sequence are executed one after the other, i.e. the start of the second cutting sequence occurs after the end of the first cutting sequence, and, at the end of the first cutting sequence, the direction of rotation R20+, R20- of bandage 1 is reversed, so as to execute the second cutting sequence, as illustrated in Figures 7A and 7B, using a second direction of rotation R20+ which is of opposite sign to the first direction of rotation R20- which was used during the first cutting sequence, here illustrated in Figures 6A, 6B and 6C.

[0106] Advantageously, this allows each hemisphere H1, H2 to be taken in the correct direction, as said correct direction is defined by the orientation A6, A6' of the reinforcing wires in said hemisphere.

[0107] We can therefore slide the cutting tool 2, 2' in contact with the reinforcing layer(s) 5, 5', along the reinforcing wires 6, 6', in each of the two hemispheres H1, H2, on both sides of the equatorial plane P_EQ, without risk of tearing the said reinforcing wires 6, 6'.

[0108] This will maximize the amount of material recovered, as can be seen in figures 7A and 7B.

[0109] To do this, it will be advantageous to use the first cutting tool 2, in association with the first direction of rotation, here the direction of rotation R20- negative, in the first hemisphere H1, and more preferably to servo said first cutting tool 2 in radial force in said first hemisphere then, after reversing the direction of rotation R20, to use the second cutting tool 2', suitably oriented with respect to the second direction of rotation, here the direction of rotation R20+ positive, to machine the second hemisphere H2, here preferably by servo said second cutting tool 2' in radial force, in a manner analogous to what has been described above.

[0110] According to another possible implementation, the first cutting sequence and the second cutting sequence are executed using the same direction of rotation R20+, R20-, and it is provided for the possibility of introducing into the second cutting trajectory T2_2 which is applied in the second hemisphere H2 a centrifugal radial offset Delta_T2 with respect to the first cutting trajectory T2_l which is applied in the first hemisphere Hl, so as to preserve, in all or part of the second hemisphere H2 a residual overthickness Delta_4 of outer layer 4 which protects the reinforcing wires 6 from tearing in said second hemisphere H2, as illustrated in Figure 8B.

[0111] If necessary, it is even possible, provided that two cutting tools 2, 2' are properly oriented to engage each of the outer layer in view of the direction of rotation R20+, R20- applied, for example if one were to consider a variant arrangement in which a first cutting tool 2 would point upwards on the right part of figure 2 and a second cutting tool 2' would point downwards, rather than upwards, on the left part of figure 2, to execute the first cutting sequence and the second cutting sequence simultaneously, and thus reduce the cycle time.

[0112] Maintaining a single direction of rotation R20+, R20- to process both hemispheres HI, H2 advantageously avoids having to stop the R20 rotation of the support 20, nor a fortiori to restart and re-accelerate support 20 in the opposite direction of rotation, between the two cutting sequences.

[0113] By eliminating these transient regimes, and therefore in particular the corresponding disadvantages due to the inertial behavior of the support 20 carrying the bandage 1, we advantageously reduce the cycle time, and we save energy.

[0114] However, because the direction of rotation R20+, R20- is not reversed between the two cutting sequences, the orientation A6, A6' which places the ends of the reinforcing wires 6, 6' in the right direction in the first hemisphere H1, with regard to the direction of rotation, places the opposite ends of these same wires 6, 6' against the grain in the second hemisphere H2.

[0115] This is why, advantageously, we plan to be able to introduce a centrifugal radial offset Delta_T2 which allows the cutting tool which processes the second hemisphere H2, whether it is the first cutting tool 2 or the second cutting tool 2', to pass radially away from the areas of the second hemisphere in which said cutting tool must not be in contact with the reinforcing wires 6, 6' in order not to tear them out.

[0116] As a guideline, the radial centrifugal shift Delta_T2 will preferably be between 1 mm and 3 mm.

[0117] It is possible to implement an evolving, and more preferably progressive, radial centrifugal offset Delta_T2, for example which will be zero at the abscissa of the equatorial plane P_EQ, at the starting point K2 of the second cutting trajectory T2_2, and which will become positive from a certain axial distance from the equatorial plane P_EQ, which in this case precedes the axial position of the second edge 5 2 of the reinforcement layer 5 in the second direction of axial path S2_2, so that the cutting tool, here the second cutting tool 2', will move away from the reinforcement wires 6, in order to create the overthickness Delta_4, and thus leave a residual thickness of outer layer 4, only when the cutting tool 2' approaches the second edge 5 2 of the reinforcement layer 5 located in the second hemisphere H2 and passes over said second edge 5 2.

[0118] Preferably, the first cutting tool 2 is positioned and moved by a first master positioning system 42 which executes the first cutting path T2_l so as to slide said first cutting tool 2 into contact with the reinforcing layer 5, along Reinforcing wires 6, preferably by servo-controlling the first cutting tool 2 with a radial force, while the second cutting tool 2' is positioned and moved by a second slave positioning system 42', which defers in time the execution of the second cutting path T2_2 relative to the execution of the first cutting path T2_1, so that the lead given to the first positioning system 42 allows the crossing of edges 51, 5'1 of reinforcement layers 5, 5' in the first hemisphere to be revealed and thus detected. Therefore, the second positioning system 42' can servo-control the second cutting tool 2' in a radial position, by applying a second cutting path T2_2 constructed from the first cutting path T2_1, to which are integrated, if necessary, one or more centrifugal radial offsets Delta_T2 allowing the second cutting tool 2' to be radially retracted relative to the reinforcement layers. 5, 5 minutes before, or when,said second cutting tool 2' reaches the corresponding edges 5 2, 5' 2 of the reinforcing layers 5, 5' in the second hemisphere H2.,

[0119] More generally, preferably, we detect a crossing by the cutting tool which processes the first hemisphere of a first edge 5 1 of the reinforcement layer 5 in the first hemisphere H1, and we control the cutting tool which processes the second hemisphere, whether it is the same cutting tool or another cutting tool, so as to introduce into the second cutting trajectory T2_2 a radial centrifugal shift Delta_T2 which allows the cutting tool processing the second hemisphere H2 to pass radially at a distance from the reinforcement layer 5 when said cutting tool passes through an abscissa which is the mirror image, with respect to the equatorial plane P_EQ, of the abscissa of the first edge 5 1 crossed in the first hemisphere H1.

[0120] The centrifugal radial shift Delta_T2 can be introduced in the form of a step or several successive steps, at a given axial abscissa or respectively successive axial abscissas, or in a progressive form, for example by means of a ramp which extends over a given axial range.

[0121] Preferably, the cutting tool processing the first hemisphere, for example the first cutting tool 2, being radially controlled, radial positions are measured during the execution of the first cutting sequence. These radially controlled positions are then successively adopted by the cutting tool 2 along the first cutting path T2_l in contact with the reinforcement layer 5, and the cutting tool handling the second hemisphere is controlled accordingly. hemisphere H2, here for example the second cutting tool 2', in radial position, from the measured radial positions of the first cutting tool 2, so as to be able to introduce a centrifugal radial offset Delta_T2 in the second cutting trajectory T2_2 if we detect, in the first hemisphere H1, a variation in radial position of the cutting tool 2 which is representative of the axial crossing, by said cutting tool 2, of an edge 5 1 of the reinforcement layer 5.

[0122] Thus, it is the first cutting tool 2 itself that will be used to detect the crossing by the first cutting tool 2 of a first edge 5 1, 5' 1 of a reinforcement layer 5, 5' in the first hemisphere Hl, acting like a probe whose radial position is monitored in order to detect the variations in radial position induced by the arrangement of the reinforcement layer(s) 5, 5'.

[0123] The correction of the second cutting trajectory T2_2 will then be triggered in response to the detection of a 5 1 edge in the first hemisphere H1 to preserve the integrity of the reinforcement layer 5, and of the corresponding cutting tool, here for example the second cutting tool 2', when crossing the equivalent 5 2 edge in the second hemisphere H2.

[0124] Of course, the invention also relates to an installation 40 enabling the implementation of a process as described above.

[0125] The installation 40 thus includes, as can be seen in figures 1 and 2, a rotating support 20 which is arranged to receive the tire 1, which rotating support 20 is mounted in rotation on a frame 30 around a main axis Z20, here horizontal, and associated with a drive system 41, preferably including an electric motor, which allows to drive said rotating support 20, and therefore the tire 1, in rotation R20 on itself around said main axis Z20, according to a determined direction of rotation R20+, R20-.

[0126] The installation 40 also includes a first cutting tool 2, as well as a first positioning system 42 which carries the first cutting tool 2, preferably at the end of a first robotic arm 44, and which allows the positioning and movement of said first cutting tool 2 relative to the frame 30, and more particularly relative to the main axis Z20, so as to make the first cutting tool 2 follow a first trajectory cutting T2_l while the support 20 drives the bandage 1 in rotation R20, so as to remove material from the outer layer 4 of the bandage 1.

[0127] Although it is possible to consider using a single cutting tool 2 to dig the trench and then proceed successively to each of the first and second cutting sequences, it is preferable to have two separate cutting tools.

[0128] Thus, the installation 40 preferably includes a second cutting tool 2', separate from the first cutting tool 2, and a second positioning system 42' which carries the second cutting tool 2', preferably at the end of a second robotic arm 44', and which allows the second cutting tool 2' to be positioned and moved relative to the frame 30, and more particularly relative to the main axis Z20, so as to make the second cutting tool 2' follow a second cutting path T2_2, separate from the first cutting path T2_1, while the support 20 drives the band 1 in rotation R20, so as to remove material from the outer layer 4 of the band 1.

[0129] Preferably, each of the first and second positioning systems 42, 42' can reach and traverse indifferently the first hemisphere H1, the second hemisphere H2, or each of the two hemispheres H1, H2. It will thus be possible to freely select the cutting tool 2, 2' and the hemisphere H1, H2 adapted to a given direction of rotation R20+, R20- and to the observed orientation A6, A6' of the reinforcing wires.

[0130] The first and / or second positioning system 42, 42', and more particularly one and / or the other of the first and second robotic arms 44, 44', may include a pneumatic cylinder to radially press the corresponding cutting tool 2, 2' against the wall 3 of the tire 1, and where appropriate to servo said cutting tool in radial force.

[0131] Preferably, as can be seen in figures 1, 2 and 9, the first cutting tool 2 and the second cutting tool 2' are formed respectively by a first cylindrical knife 25 and a second cylindrical knife 25', whose respective circular edges 25A, 25'A form the cutting edges and are oriented so as to engage the wall 3 in opposition to the chosen direction of rotation R20+, R20-.

[0132] Such cylindrical knives, 25 and 25 inches, advantageously provide a precise, clean, and regular cut, which allows the constituent material of the outer layer to be removed. 4 in the form of chips or strips, and potentially right up to the reinforcing wires 6.

[0133] The generating axis Z25, Z25', around which each cylindrical knife 25, 25' considered rotates in rotation R25 on itself while the tire 1 is itself driven in rotation R20 by its support 20, is advantageously oriented so that said cylindrical knife 25, 25', and more particularly its edge 25A, 25'A, is presented in a substantially tangent manner to the apparent, moving surface of the wall 3, and more preferably slightly oblique with respect to said apparent surface.

[0134] Thus, more preferably, in order to promote the penetration of the edge 25A, 25'A of the cylindrical knife 25, 25' into the wall 3 and to clear the space necessary for the corresponding positioning system 42, 42', the generating axis Z25, Z25' of the cylindrical knife will have, in a plane normal to the main axis Z20, and more particularly in a plane normal to the main axis Z20 passing through the point of the edge 25 A, 25'A which is in contact with the wall 3 and closest to the main axis Z20, an angle of inclination with respect to the tangent to the perimeter of the wall 3, for example an angle of inclination of the order of 15 degrees, as can be seen in the figure 2.

[0135] The orientation of the cylindrical knives 25, 25' will of course depend on how we want to implement the cutting sequences.

[0136] Thus, if we wish to treat each hemisphere H1, H2 with a different knife 25, 25', and using for each a different direction of rotation R20+, R20- of bandage 1, then the first knife 25 will have to point in opposition to the first direction of rotation, here in opposition to the negative direction R20-, therefore upwards on the right part of figure 2, while the second knife 25' will point in opposition to the second direction of rotation, here in opposition to the positive direction of rotation R20+, therefore also upwards but on the left part of figure 2, diametrically opposite to the first knife 25 with respect to the main axis Z20.

[0137] Conversely, if we wish to engage both knives 25, 25' simultaneously, considering a single direction of rotation, here for example the negative direction of rotation R20, then the first and second cylindrical knives 25, 25' must each point in the same circumferential direction, so that, here, in Figures 1 and 2, the first knife cylindrical 25, located to the right of the main axis Z20, points upwards, against the direction of rotation R20- negative, while the second cylindrical knife 25', diametrically opposite, located to the left of the main axis Z20, should point downwards (and no longer upwards as shown in the figures).

[0138] Furthermore, each of the first and second cylindrical knives 25, 25' will preferably be equipped with a sharpening system 45, 45', including for example a sharpening wheel, which will allow the cutting edge to be sharpened automatically during or after the cutting operation.

[0139] For each knife 25, 25' likely to slide in contact with a reinforcing layer 5, 5', the edge 25 A, 25 'A forming the cutting edge will preferably be smooth, appearing as a continuous wall, without indentations, as illustrated in Figure 9 and on the straight parts of Figures 1 and 2. Such a smooth edge 25 A, 25 'A will in particular have the advantage of not having any roughness likely to accidentally catch a reinforcing wire 6.

[0140] Preferably, the cylindrical knife 25, 25' will have a diameter between 100 mm and 300 mm.

[0141] Each of the first and second cylindrical knives 25, 25' can also be associated with a chip evacuation chute 46, 46', as illustrated in Figures 1 and 9, which chute 46, 46' will guide the material removed from the band 1 towards a recovery system, comprising for example a discharge conveyor which may itself open directly above a recovery bin into which said conveyor will discharge the material extracted from the outer layer 4 of the band 1

[0142] Installation 40 also includes a control unit 51 which allows installation 40 to be controlled automatically.

[0143] Said control unit 51 includes a pilot unit 52 arranged to pilot the drive system 41 in order to implement the rotation R20 of the support 20 and to pilot and coordinate the first and second positioning systems 42, 42' in order to execute the first and second cutting path T2_l, T2_2.

[0144] The control unit 51 also includes a bandage analysis system 53 which makes it possible to identify, for example by means of an optical detection device 50 which may include a profilometer, a laser rangefinder, and / or a camera associated with image processing, the radial envelope distance D0_ply, and / or the A6 orientation of the reinforcing wires, as explained above.

[0145] The control unit 51 further includes a cutting sequence adaptation unit 54, which is arranged to define the first cutting trajectory T2_1 and the second cutting trajectory T2_2.

[0146] In particular, the cutting sequence adaptation unit 54 is capable of defining a first and / or a second cutting trajectory T2_l which presses the corresponding cutting tool 2, 2' against the reinforcing layer 5, 5', to slide said cutting tool 2, 2' into contact with the reinforcing wires 6, 6'.

[0147] The cutting sequence adaptation unit 54 can also select the hemisphere H1, H2 adapted to the cutting tool 2, 2' considered, according to the direction of rotation R20+, R20- and the orientation A6 of the reinforcing wires, or, equivalently, adapt the direction of rotation R20+, R20-, and select the cutting tool 2, 2', according to the hemisphere to be treated and the orientation A6 of the reinforcing wires in that hemisphere.

[0148] The cutting sequence adaptation unit 54 may also include, where appropriate, a radial centrifugal offset Delta_T2 to radially retract the cutting tool 2, 2' concerned in the portions of one and / or the other of the first and second cutting trajectories T2_1, T2_2 in which the reinforcing wires 6, 6' are in opposition to the action of the cutting tool 2, 2', and more particularly in which the circumferential component Aô circ of the direction vector along which the reinforcing wires 6, 6' extend is of opposite sign to the circumferential component V2_circ of the velocity vector V2 along which the cutting tool 2, 2' moves relative to the wall 3 of the bandage, and therefore in particular relative to the corresponding reinforcing layer 5, 5'.

[0149] The control unit 52, the band analysis system 53 and the cutting sequence adaptation unit 54 will preferably be electronic or computer-based, and will allow for the automatic execution of the trenching, band analysis, and cutting sequence execution steps.

[0150] The control unit 52, the bandage analysis system 53, and the cutting sequence adaptation unit 54 could advantageously be grouped within the control unit 51, which is for example formed by a computer or an industrial programmable logic controller.

[0151] Of course, the invention is by no means limited to the variant embodiments described above, the person skilled in the art being able in particular to isolate or freely combine one or the other of the aforementioned characteristics, or to substitute equivalents for them.

Claims

CLAIMS 1. Method for machining a bandage (1), said bandage (1) having a wall (3) which comprises at least one external layer (4) based on elastomer and at least one reinforcing ply (5) which is located under said external layer (4) and which contains a plurality of reinforcing threads (6), said method being characterized in that it comprises: - a trench digging step, during which the bandage (1) is fixed on a rotating support (20) having an axis of rotation called the "main axis" (Z20), and by means of said support (20) the bandage (1) is driven in rotation on itself, around said main axis (Z20), in a chosen direction of rotation (R20+, R20-), a cutting tool (2) is positioned opposite the bandage (1) at an axial abscissa included in an axial range called the "equatorial zone" which on the one hand represents less than 35% of the axial range (Wl) covered by the bandage (1), preferably less than 30% of the axial range (Wl) covered by the bandage (1), more preferably less than 25% of the axial range (Wl) covered by the bandage 1, or even less than 20%, less than 15% or even less than 10% of the axial range axial (W 1) covered by the bandage (1),and which on the other hand contains the fictitious plane called the “equatorial plane” (P_EQ) which is normal to the main axis (Z20) and which passes through the middle of the axial range (Wl) occupied by the bandage (1), said equatorial plane (P_EQ) thus dividing the bandage (1) into a first hemisphere (Hl) and a second hemisphere (H2), then, while the bandage (1) is driven in rotation (R20) around the main axis (Z20), the cutting tool (2) is engaged in the internal layer (4), according to a centripetal radial penetration movement directed towards the reinforcement ply (5), so as to dig in the external layer (4) a circumferential trench (27) located at the chosen axial abscissa, in the equatorial zone;, - then a material removal step during which a first cutting sequence is executed during which the bandage (1) is rotated on itself, around the main axis (Z20), in a chosen direction of rotation (R20+, R20-), and a cutting tool (2) is made to follow a first cutting path (T2_l) along which said cutting tool (2) axially travels the first hemisphere (Hl), from the trench (27), in order to remove material from the external layer (4) in said first hemisphere (Hl), and a second cutting sequence during which the bandage (1) is rotated on itself, around the main axis (Z20), in a chosen direction of rotation (R20+, R20-), and a cutting tool (2, 2') is made to follow a second cutting path (T2_2) according to which said cutting tool (2, 2') axially travels the second hemisphere (H2), from the trench (27), in order to remove material from the external layer (4) in said second hemisphere (H2).

2. Method according to claim 1 characterized in that during the trench digging step, the outer layer (4) is dug until the bottom of the trench (27) reaches the reinforcement layer (5).

3. Method according to claim 1 or 2 characterized in that it comprises a step of analyzing the bandage during which the radial distance called "radial envelope distance" (D0_ply) at which the radially external limit of the reinforcing wires (6) of the reinforcing ply (5) which is located immediately under the external layer (4) is evaluated, preferably by detecting an arrival of the trench (27) at the reinforcing ply (5), in the absence of radial stress exerted on the wall (3) by a cutting tool (2, 2'), relative to the main axis (Z20), then a step of defining the cutting path during which the first cutting path (T2_l) is defined, and preferably also the second cutting path (T2_2), from the radial envelope distance (D0_ply), by fixing the radial position of the starting point (Kl) of the first cutting path (T2_l),and preferably also the radial position of the starting point (K2) of the second cutting path (T2_2), at a radial distance from the main axis (Z20) which is less than the radial envelope distance (D0_ply) by a non-zero value called “nominal deflection value” (DO bend), said nominal deflection value preferably being between 1 mm and 5 mm, more preferably between 2 mm and 5 mm, for example equal to 3 mm., 4. Method according to one of the preceding claims, characterized in that the first cutting sequence is carried out by bringing the cutting tool (2) into contact with the reinforcing ply (5) and then axially moving the cutting tool (2) by sliding the first cutting tool (2) into contact with the reinforcing ply (5), along the reinforcing wires (6), in the first hemisphere (H1).

5. Method according to claim 4 characterized in that the cutting tool (2) is controlled by radial force while said cutting tool (2) is moved axially along the first hemisphere (Hl), so as to maintain the cutting tool (2) in sliding contact with the reinforcing ply (5), along the reinforcing wires (6).

6. Method according to one of the preceding claims, characterized in that, the reinforcing threads (6) having an orientation (A6) oblique to the equatorial plane (P_EQ) and interrupted at a first edge (5 1) of the reinforcing ply (5) which is located in the first hemisphere (Hl) axially distant from the equatorial plane (P_EQ), the first cutting sequence is adapted so that the relative displacement (V2) of the cutting tool (2) relative to the reinforcing ply (5) has on the one hand a circumferential displacement component (V2_circ), induced by the rotation (R20) of the bandage, which is of the same sign as the circumferential component (Aô circ) of the orientation (A6) of the reinforcing threads, considered when said reinforcing threads (6) are traversed from the equatorial plane (P_EQ) towards the first edge (5 1) of the reinforcing ply, and on the other hand an axial displacement component (V2_ax),which corresponds to the direction in which the cutting tool (2) axially travels the first hemisphere (Hl), which axial displacement component (V2_ax) has the same sign as the axial component (A6_ax) of the orientation (A6) of the reinforcing wires (6), considered when traveling through said reinforcing wires (6) from the equatorial plane (P_EQ) towards the first edge (5 1) of the reinforcing ply., 7. Method according to one of the preceding claims, characterized in that the first cutting sequence is carried out by means of a first cutting tool (2), and the second cutting sequence is carried out by means of a second cutting tool (2') separate from the first cutting tool (2).

8. Method according to one of the preceding claims, characterized in that the first cutting sequence and the second cutting sequence are executed one after the other, and in that, at the end of the first cutting sequence, the direction of rotation (R20+, R20-) of the bandage (1) is reversed, so as to execute the second cutting sequence using a second direction of rotation (R20+) which is of the opposite sign to the first direction of rotation (R20-) which was used during the first cutting sequence.

9. Method according to claim 7 characterized in that the first cutting sequence and the second cutting sequence are executed using the same direction of rotation (R20+, R20-), and in that the possibility is provided of introducing into the second cutting path (T2_2) which is applied in the second hemisphere (H2) a centrifugal radial offset (Delta_T2) relative to the first cutting path (T2_l) which is applied in the first hemisphere (Hl), so as to preserve, in all or part of the second hemisphere (H2) a residual excess thickness (Delta_4) of external layer (4) which protects the reinforcing threads (6) from tearing in said second hemisphere (H2).

10. Method according to one of the preceding claims, characterized in that the bandage (1) has a first annular heel (7) and a second annular heel (8), provided respectively with a first bead wire and a second bead wire, in that the wall (3) of the bandage forms a radially external crown (10), as well as a first flank (11) which connects said crown (10) to the first heel (7) and a second flank (12) which connects the crown (10) to the second heel (8), and in that the rotating support (20) is arranged to hold the bandage (1), preferably in an uninflated state, by the first heel (7) and second heel (8), leaving the top (10) free to deform elastically under the pressure of the cutting tool (2).

Images