EP3390030A1

EP3390030A1 - Drum for building and shaping a tyre carcass

Info

Publication number: EP3390030A1
Application number: EP16826102.2A
Authority: EP
Inventors: Henri Hinc; Jean-Marie Dettorre
Original assignee: Compagnie Generale des Etablissements Michelin SCA
Current assignee: Compagnie Generale des Etablissements Michelin SCA
Priority date: 2015-12-18
Filing date: 2016-12-15
Publication date: 2018-10-24
Also published as: US20200269533A1; CN108472898A; WO2017103501A1; FR3045455B1; FR3045455A1

Abstract

This drum (1000) for building and shaping a tyre carcass, comprises: - a surface (1106, 1506, 1206) for building a tyre carcass that is generally cylindrical in shape, having a main axis of rotation, - first and second movable surface supports, - adjustment members (1980, 1600, 1400, 1450) for adjusting a diameter of the surface, - adjustment members for adjusting an axial distance between the first and second supports. The drum further comprises first means (1700, 1800) for sealed connection between the surface and at least one of the first or second supports, and second means for sealed connection between the first and second supports.

Description

Drum for making and shaping a tire carcass

The invention lies in the technical field of tire manufacturing. It relates in particular to the manufacture and conformation of a tire carcass. According to a known method, the manufacture of a tire blank mainly comprises two steps.

The first step corresponds to the manufacture of the carcass of the future tire. This carcass generally comprises one or more sealing layers, one or more carcass plies, two circular rods, and various other rubber products intended, for example, to reinforce the flanks and the lower zone of the future tire. These elements are assembled flat, on top of each other, on a so-called manufacturing drum. On this manufacturing drum, the carcass constituted by the assembly of these different elements is cylindrical. At the end of this first step, a bending is usually carried out consisting in turning the ends of the carcass around the rods.

The second step is finishing. In a first step, a conformation is carried out consisting in passing the carcass from a cylindrical shape to the toroidal shape of the future tire. For this purpose, the carcass is mounted on a drum called "finishing" or "conformation" to inflate the carcass, for example through a flow of air, and at the same time decrease the distance between the rods of the carcass, called "inter-rod distance". In a second step, once the carcass has been shaped, the components of the crown of the future tire are assembled on the shaped carcass. These components include in particular one or more crown plies and the tread of the future tire. These components can be assembled one after the other directly on the shaped carcass. Alternatively, these components are preassembled to a cylindrical shape and this pre-assembly is then transferred to the shaped carcass via a transfer ring.

Once the vertex components are assembled to the toroidal casing, the tire blank is ready to be placed in a baking mold where the various rubber components of the future tire will be vulcanized. The vulcanization step leads to the finished tire.

The present invention is more particularly concerned with the manufacture of the carcass and with the conformation of this carcass with a view to finishing the tire blank. These steps are generally carried out on respectively making and finishing drums whose diameters preferably correspond substantially to the diameter, at a bead formed by the bending, of the future tire, also called "Seat diameter". This also corresponds to the inside diameter of the tire, or in other words to the diameter of the rim of the future wheel comprising the tire. In what follows, only the diameter of the tire will be referred to to denote this dimension. Different types of tires may have different diameters, different crown widths, and different sidewall heights, and therefore different inter-rod distances. However, each garment drum and finishing drum is generally used for the manufacture of a tire blank to a given single diameter. Therefore, to manufacture tires of different diameters, it is necessary to design, manufacture, store and maintain a plurality of packaging drums and a plurality of finishing drums.

Already known in the state of the art, in particular according to EP1674249, a drum adapted to perform both the manufacture and conformation of a tire carcass but it is also adapted to a single type of tire. It has means for adjusting the diameter, but these adjustment means can only slightly modify the diameter of the drum in its central portion. Indeed, these adjustment means allow to slightly extend the diameter of the central portion of the drum for the manufacture of the lower part of the flanks of the future tire at the rods, or to retract slightly this central portion to allow extract the blank. The drum is therefore adapted only to a given tire diameter. The means for adjusting the distance of between-rods can vary this distance only to achieve the conformation of the blank, without allowing to make carcasses with different distances between-rods. The conformation of the carcass is achieved by blowing air.

Thus, the drum described in EP1674249 only halves the number of drums required for the manufacture and finishing of tires. For each tire having a specific diameter and / or inter-linkage distance, a different drum must be used.

The object of the invention is to limit the number of drums for manufacturing tires of different diameters and inter-linkage distances.

For this purpose, according to the invention there is provided a drum for making and shaping a tire carcass, comprising:

a manufacturing surface of a generally cylindrical tire carcass having a main axis of rotation,

first and second movable supports of the surface,

- adjustment devices of a diameter of the surface,

- Adjusters for an axial distance between the first and second supports, further comprising first sealing means between the surface and at the least one of the first or second supports, and second sealing means between the first and second supports.

Thus, the first and second sealing means partially delimit an air chamber to perform the conformation of the carcass by blowing the central portion of the latter with the air of the air chamber. In the invention, the diameter adjustment members make it possible to adapt the drum to the different diameters of the tires to be manufactured. Moreover, the axial distance adjusting members between the first and second supports make it possible to adapt the drum to the inter-linkage distance of the tire to be manufactured. Thus, this drum is adaptable to the manufacture of different types of tires having different seat diameters and different crown widths (thus different inter-rail distances). It allows more both the making and the conformation of the carcass. The number of drums to be manufactured, stored and maintained is therefore considerably reduced.

Advantageously, the drum comprises first and second sets of end segments forming end portions of the surface, each segment of the first assembly being mounted radially movable on the first support, the first support being common to the segments of the first together, each segment of the second set being radially movably mounted on the second support, the second support being common to the segments of the second set. Thus, the end segments support the tire carcass, and their adjustable radial positioning makes it possible to adjust the diameter of the surface of the drum so as to adapt it to the diameter of the tire to be manufactured.

Preferably, the first sealing connection means comprise at least one radially elastically deformable radial sealing membrane in accordance with an adjustment of the diameter of the surface, the membrane sealingly connecting the end segments of one sets of end segments to the support which is common to the end segments of this set. Thus, the membrane adapts to the adjustment of the diameter of the surface of the drum and performs for all diameters its sealing function.

Advantageously, the membrane comprises annular bellows folds and radial folds distributed around the annular folds and extending to a periphery of the membrane. Thus, the annular folds make it possible to extend the membrane radially while the radial folds make it possible to extend the perimeter of the membrane as a function of its radial expansion.

Preferably, the second sealing connection means comprise an axially deformable axial sealing member as a function of a distance adjustment. between the first and second supports and sealingly connecting the first and second supports. Thus, the axial sealing member makes it possible, at least in part, to provide the seal required for shaping the blank while adapting to the adjustment of the inter-rod distance relating to the width of the tire to be manufactured. .

Advantageously, the axial sealing member comprises telescopic tubes sliding axially between them as a function of the adjustment of the distance between the first and second supports.

Preferably, the distance adjusting members between the first and second supports and the surface diameter adjusting members each comprise a worm, the two screws extending axially through the axial sealing member. Thus, the worms allow, independently of one another, to adjust the diameter of the surface and the distance between the rods of the drum and thus to adapt to the dimensions of the tire to be manufactured.

Advantageously, the surface diameter adjustment members comprise first and second cam profiles intended to cooperate with respectively first and second members for tracking these profiles carried by the first and second sets of end segments, respectively. and second cam profiles being carried respectively by first and second cams, the two cams being movable in a direction parallel to the axis, the first and second cam profiles respectively transforming a displacement of the first and second cams into a radial displacement respectively first and second end segment sets. Thus, both cams operate symmetrically and, depending on their axial positioning, adjust the diameter of the drum surface.

Preferably, the distance adjustment members between the first and second supports comprise relative axial displacement members of the first and second supports.

Advantageously, the drum further comprises a set of central segments forming a central portion of the surface, each central segment being carried by at least one axial rod slidably mounted on two end segments. Thus, when the distance between the drum-links varies, that is to say when the distance between the first and second supports varies, the end segments move by sliding at the rod, and particularly of on each side of each central segment, while each central segment remains in the same position relative to the rod. When the diameter of the surface varies, all the central and end segments move radially synchronously.

Preferably, the membrane has at least one passage opening of the axial rod. Thus, the membrane follows the end segments to which it is connected when move, sliding relative to the axial rod.

Advantageously, the first and second sets of end segments respectively bear first and second annular positioning grooves respectively of first and second rods. Thus, the grooves allow to position the rods of the carcass on the drum. The inter-rod distance therefore corresponds substantially to the distance between these grooves and can vary from one tire to another.

Preferably, within one of the sets of end segments, two circumferentially adjacent segments have tooth and crestal complementary edges. Thus, as the diameter of the drum surface increases, the circumferentially adjacent segments deviate from each other. However, the shape of the separation between the segments comprising slots, no axial rectilinear rupture is generated within the surface of the drum, so that the risk of pinching the carcass on the surface of the drum is limited when the diameter of the surface increases.

An embodiment of the invention will now be described by way of nonlimiting example and with reference to the appended drawings in which:

- Figure 1 is a perspective view of a drum according to the invention, the inter-rod distance and the diameter being retracted;

FIG. 2 is a view of the same drum, the inter-rod distance and the diameter being expanded;

FIG. 3 is a view in median longitudinal section of the drum of FIG. 2;

- Figures 4, 5 and 6 are views of a membrane according to the invention respectively in median section and in perspective while the membrane is retracted, and in perspective while the membrane is expanded;

- Figure 7 is an axial longitudinal sectional view of an axial sealing member according to the invention;

- Figures 8, 9, and 10 are diagrams illustrating steps of a method of making and conforming a tire carcass according to the invention.

In the following, will be designated by carcass a tire in a cylindrical state preceding the shaping, and roughing a shaped tire, not yet cooked. The blank is therefore derived from a manufactured and shaped carcass, on which the vertex shapes were laid.

Figures 1 to 3 illustrate a drum 1000 of manufacture and conformation of a tire carcass according to the invention. It comprises first and second sets 1100 and 1200 of end segments, the assembly 1100 comprising in particular a segment 1106 and the assembly 1200 a segment 1206. These sets of segments 1100 and 1200 form end portions of a manufacturing surface of a generally cylindrical tire carcass having a main axis of rotation X, Referring to FIGS. 2 and 3, each end segment of the first assembly 1100 is radially movably mounted, relative to the X axis, on a first movable support 1310 axially common to the segments of the first set 1100. The visible support 1310 in Figure 3 has a generally cylindrical shape. Similarly, each end segment of the second set 1200 is mounted radially movable on a second movable support 1410 axially common to the segments of the second set 1200.

The drum 1000 further comprises a set 1500 of central segments, including in particular a central segment 1506 forming a central portion of the surface of the drum 1000. Each central segment is carried by at least one axial rod slidably mounted on two end segments. Thus, the central segment 1506 is carried by the rod 1002 slidably mounted on the two end segments 1106 and 1206.

Within one of the sets of end segments, for example within the assembly 1100, all the circumferentially adjacent segments, in particular the segments 1106 and 1108 illustrated in FIG. 2, have complementary edges with teeth and crenellations. This shape of the edges of the segments has the following advantage: as the diameter of the surface of the drum 1000 increases, the segments deviate from each other in the circumferential direction. However, if the segments had straight edges, then the spacing between the segments would cause rectilinear breaks along the surface of the drum, between each segment. The carcass placed on the drum could then be pinched in this type of break. Here, thanks to the teeth and crenels, the breaks in the axial direction are intermittent, so that there is much less risk of pinching the carcass.

The first and second sets of end segments 1100 and 1200 respectively carry first and second annular grooves 1111 and 1112 respectively for positioning first and second carcass rods. These grooves are removable, so that for a given diameter of the drum surface there is a pair of adapted grooves, which can be replaced by another pair when the diameter of the surface evolves to manufacture a tire of different diameter. Alternatively, grooves may not be used. It is indeed possible, for example, to compress the rods between the carcass and the surface of the drum.

The surface of the drum 1000 may change in diameter so as to be suitable for several types of tires to be manufactured, each tire may have a different diameter. As written above, the diameter is the diameter at the bead of the finished tire, corresponding substantially to the rim diameter of the future vehicle wheel. It is also called "seat diameter". It also corresponds to the diameter of the carcass in the cylindrical state.

We will now explain how the change in diameter of the surface of the drum works. In the following, we will discuss indifferently the diameter of the drum or the diameter of the surface.

The drum diameter adjusting members comprise first and second cam profiles. One of these cam profiles, 1400, is visible in Figure 1, the other being placed symmetrically at the assembly 1100 and not shown. Everything about the 1400 profile is valid for the symmetrical profile.

The cam profile 1400 is revolution about the main axis of rotation of the drum, and comprises several diameter levels, which evolve in the axial direction. These diameter levels make it possible to adjust the diameter of the surface of the drum. Indeed, these first and second cam profiles are intended to cooperate with respectively first and second cam profile monitoring members, only one of these bodies 1450 being visible. They are carried respectively by the first 1100 and second 1200 sets of end segments. These members and in particular the member 1450 comprise a series of bearings capable of rolling on the cam profiles. These bearings are visible in Figures 1 to 3. Thus, for example, when the bearings pass from one diameter of the cam profile 1400 to another, the end segment 1206, carried by one of the bearings, changes position. radial. Since the bearings of the member 1450 are distributed circumferentially around the cam profile 1400, all the end segments of the assembly 1200 move in a radial direction synchronously. This also applies to the segments of the assembly 1100. This is how the diameter of the drum 1000 evolves.

The first and second cam profiles are respectively carried by first and second cams, in particular the visible cam 1600 in FIG. 2 which carries the profile 1400. The two cams are movable in a direction parallel to the main axis X of the drum. The cams operate synchronously and move symmetrically, either toward or away from the central portion of the drum. This displacement generates a rolling of the first and second members, in particular of the member 1450, at the level of the cam profiles. The diameter of the profiles evolving along the X axis, when the cams move axially, the bearings and therefore the end segments supported by the bearings move radially. Thus, the first and second cam profiles respectively transform a displacement of the first and second cams into a radial displacement respectively of the first and second 1100 and 1200 end segment assemblies.

To be displaced, the cams are fixed to a worm 1980, visible in Figures 1 to 3. Depending on the rotation of the screw 1980, the cams move in one direction or the other along the X axis. It is the displacements of the cams due to the rotation of the screw 1980 which thus make it possible to modify the diameter of the drum.

The drum is also able to adapt to the inter-rod distance of the carcass to be made and to conform. This inter-rods distance, also called "inter-rods" in the following, corresponds to the distance between the rods of the future tire.

We will now describe how the modification of the inter-rods works.

The adjustment members of the inter-rods move the two supports 1310 and 1410 axially according to the rotation of an endless screw 1950 visible in Figure 3. The two supports move away or approach one of the the other, depending on the rotation of the screw 1950. Therefore, the end segments common to these supports are moving toward or away from each other. Thus, the end supports 1106 and 1206 move away from or approach the central segment 1506 as a function of the rotation of the screw 1950. The annular grooves 1111 and 1112 being placed on either side of the central segments, on the end segments, they move closer or move away from each other, varying the distance of between-rods. Thus, the drum 1000 can be adapted to several inter-rod distances, depending on the dimensions of the tire to be manufactured.

It is necessary to adjust simultaneously the diameter of the drum and the distance of between-rods. Indeed, when, for example, the supports 1310 and 1410 are brought closer to one another via the screw 1950 without modifying the adjustment of the diameter, then the members 1450 roll on the cam profiles which are fixed, and the diameter of the drum evolved. In contrast, if we act on the screw 1980 to change the diameter without touching the screw 1950, then the inter-rods will vary also. It is therefore necessary to act simultaneously and synchronously on the two adjusting screws 1950 and 1980 if one wants to modify one of the dimensions without modifying the other.

The adjustment members of the inter-rods and drum diameter adjustment members each comprise a worm. These two screws 1950 and 1980 extend axially through a sealing member 1900 described below. The inter-rod adjustment members may also comprise relative axial displacement members of the first and second supports 1310 and 1410, these members taking for example the form of pneumatic or electric cylinders or any other mechanical system providing the required positioning accuracy .

The drum 1000 is able to achieve the conformation of the blank. For this purpose, he comprises sealing means forming part of an air chamber also delimited by the carcass. Indeed, the conformation is achieved by blowing air from the air chamber to the central part of the carcass, while the inter-rod distance is reduced according to a method described below.

First sealing means, between the surface and the supports 1310 and

1410, comprise two radially elastically deformable membranes 1700 and 1800 radially in relation to a diameter adjustment of the drum. These membranes are identical and have a cylindrical shape. They are made of an elastomeric material that can be reinforced with textile or metal materials. They are located on either side of the central portion of the drum 1000. The diaphragm 1700 sealingly connects the end segments of the end segment assembly 1100 to the first support 1310 which is common to the segments. end of this set. The membrane 1800 sealingly connects the end segments of the end segment assembly 1200 to the second carrier 1410 which is common to the end segments of this assembly. In the following we will describe the membrane 1700, all the characteristics being de facto the same for the membrane 1800.

The membrane 1700, illustrated in greater detail in FIGS. 4 to 7, comprises annular folds 1710 forming bellows and radial folds 1720 distributed around the annular folds and extending to a periphery of the membrane 1700. These folds 1710 and 1720 allow to adapt the radial expansion membrane and circumferential depending on the diameter of the surface of the drum 1000 setting. Indeed, when the diameter of the surface increases, the membrane is able to gain in diameter also thanks to the annular folds 1710. As the diameter increases, the perimeter of the membrane necessarily increases and this is achieved by means of the radial folds 1720. These folds 1710 and 1720 thus act as a reserve of material in order to allow the membrane to be adapted to the diameter of the drum. . In addition, each membrane has orifices for passage axial rods 1002. The membranes therefore slide at these rods when the inter-rods varies. The membranes of Figures 1, 4 and 5 are in the retracted position while the membranes of Figures 2, 3 and 6 are in this case extended radially. The membranes thus make it possible to seal a part of an air chamber, and this for all the dimensions of the drum 1000, especially regardless of the diameter of the surface. Another part of the sealing of the air chamber is performed by the carcass, while the last part of the seal is performed by second sealing means between the first and second supports 1310 and 1410.

These second means of sealing connections comprise a member 1900 axial sealing, shown in detail in Figure 7. It is deformable in the direction of the X axis, depending on a setting of the inter-rods. It tightly connects the first and second supports 1310 and 1410. It comprises six telescopic tubes 1901 to 1906 sliding axially between them depending on the setting of the inter-rods. The number of telescopic tubes can of course vary. It is these slides that allow the body 1900 to deform in the axial direction. This member associated with the two membranes 1700 and 1800 and the carcass therefore makes the sealing of the air chamber to perform the shaping step of the blank. In addition, thanks to the telescopic tubes and thus to its axial deformation, it adapts to the inter-rods of the carcass which evolves according to the distance between-rods of the tire blank to manufacture, the width of the summit of the future tire and the height of the flanks of the future tire.

Thus, the membranes 1700 and 1800 and the body 1900 make it possible to seal the air chamber, and this for different diameters and different interlacing of the carcass to be made and to conform.

With reference to the diagrams of FIGS. 8 to 10, a method of making and shaping a tire carcass in accordance with the invention will now be described.

The diaphragms of FIGS. 8 to 10 show the membranes 1700 and 1800, the supports 1310 and 1410, the cam profile 1400 (and its symmetrical shape on the other side of the drum), the axial sealing member 1900, and that the surface of the drum 1000 formed in particular by the end segments 1106 and 1206 and by one of the central segments 1506. The axial rod 1002, supporting the central segment 1506 and sliding through the membranes 1700 and 1800 and the segments d end 1100 and 1200, is also schematized.

The first step is the making of the carcass. The carcass 2 is placed on the surface of the drum. It includes first gum products, one or more sealing layers, carcass threads, and possibly other products. One or more rolling operations can be performed on the surface so as to bond the layers of the carcass to each other. The rolling is to rotate the drum while rollers come to apply pressure on the different layers of the carcass placed one after the other. The result is thus illustrated schematically in Figure 8, the carcass having at that time a cylindrical shape.

The manufacture of the carcass also includes the installation of rods. For this purpose, the drum 1000 has grooves 1111 and 1112 which are located under the central tile 1506 when the inter-rods of the drum is minimal. By inter-rods of the drum, one spoke of the distance between the supports 1310 and 1410. This is the case which is illustrated in Figure 8. In order to install the rods, we increase the distance of between-rods by turning the worm 1950 in the direction allowing to separate the supports 1310 and 1410 from one another. The diameter is adjusted synchronously by means of the screw 1980 so that it remains stable. Gorges 1111 and 1112 which were placed under the central tile are then accessible, and the rods are placed there.

In order to get the rods into the grooves and push them in as far as possible, the diameter of the drum is slightly increased, while maintaining the rods. This leads to the arrangement of FIG. 9. To increase the diameter of the drum, it is necessary to rotate the worm 1980 so as to move the cams. Considering only the cam 1600 (the symmetric cam operates synchronously), it approaches the central part of the drum. The bearing 1450 is then moved radially as it traverses the cam profile 1400. This makes it possible to radially move the segment 1206 supported by the bearing 1450. The two cams behaving by symmetry in the same way, the set of segments end move synchronously. The central segments are supported on the rods 1002, which slide in the end segments. These central segments are held in the center of the rods for example by a spring mechanism. The central segments therefore move radially in the same way as the end segments, when the worm 1980 rotates. Simultaneously, it acts on the screw 1950 so as to maintain the entre-rods. Indeed, when the cams are approaching the central part, then the supports 1310 and 1410 also do. It is therefore necessary, to maintain the inter-rods, compensate for this approximation by moving away from one another by means of the screw 1980. In Figure 8, the carcass is placed and the rods are well embedded in the grooves through the slight increase in diameter of the drum 1000. The making of the carcass is therefore performed.

The second step is the conformation of the carcass. It is a question of transforming its cylindrical form into a toroidal form, that of the pneumatic future that it is brought to become. For this purpose it tightens the inter-rods, by rotating the worm 1950 in the direction to bring the supports 1310 and 1410. It also acts on the screw 1980 so as to move the cams one of the other to maintain the diameter of the surface during the reduction of the inter-rods. During this reduction, air is circulated at the central part of the carcass, located between the rods, so as to inflate this part. The means for supplying the air are not illustrated here and can be made by any known means. It is however necessary that the air pressure is exerted between the rods of the blank and inwardly of the blank. To prevent air leakage, an area forming an air chamber is delimited by the membranes 1700 and 1800, by the axial sealing member 1900 and the carcass itself. Sealing means in reality that the leakage rate is negligible in front of the air flow necessary to achieve the conformation of the blank.

Thus, the blank takes on a toroidal shape as illustrated in FIG. 10. During all drum diameter modifications, the first means of sealing connection between the surface and the mobile supports 1310 and 1410, including the waterproofing membranes. 1700 and 1800, are able to maintain the tightness of the air chamber, since they are deformable radially. Similarly, during the changes of the inter-rods, the second means of sealing connection between the movable supports 1310 and 1410, comprising the member 1900, are able to maintain the tightness of the air chamber, since the organ 1900 can be deformed axially by means of its telescopic elements.

At the end of the shaping step, a tread previously prepared on another drum can be deposited on the shaped carcass and still in place on the drum 1000. The blank is then obtained.

In order to extract the blank of the drum 1000, the diameter of the surface of the drum 1000 is reduced. It is then possible to remove the blank, in order to proceed to the vulcanization step (also called "cooking") which will allow the transformation of the blank into a finished tire.

In summary, a drum 1000 for making and shaping a tire carcass, comprising:

a surface, comprising in particular the segments 1106, 1506, 1206, of making a generally cylindrical tire carcass having a main axis of rotation X,

first and second movable supports 1310 and 1410 of the surface,

adjusting members (the worm 1980, the cam 1600, the cam profile 1400, the member 1450) with a diameter of the surface,

adjusting members (the endless screw 1950) having an axial distance between the first and second supports 1310 and 1410,

further comprising first sealing means between the surface and at least one of the first or second supports 1310 and 1410, including the membranes 1700 and 1800, and second sealing means between the first and second supports 1310 and 1410 , comprising the axial sealing member 1900.

Of course, we can bring to the invention many changes without departing from the scope thereof.

Claims

1. Drum (1000) for making and shaping a tire carcass, comprising:

a surface (1106, 1506, 1206) for making a generally cylindrical tire carcass having a main axis of rotation (X),

first (1310) and second (1410) movable supports of the surface,

adjusting elements (1980, 1600, 1400, 1450) with a diameter of the surface,

adjusting members (1950) having an axial distance between the first and second supports,

characterized in that it further comprises first means (1700, 1800) for sealing connection between the surface and at least one of the first (1310) or second (1410) supports, and second connection means (1900) sealed between the first and second supports.

A drum (1000) according to the preceding claim, comprising first and second sets (1100, 1200) of end segments (1106, 1206) forming end portions of the surface (1106, 1506, 1206), each segment (1106) of the first set (1100) being radially movably mounted on the first support (1310), the first support being common to the segments of the first set (1100), each segment (1206) of the second set (1200) being mounted radially on the second support (1410), the second support being common to the segments of the second assembly (1200).

A drum (1000) according to any one of the preceding claims, wherein the first sealing means comprise at least one membrane (1700,

1800) radial elastically deformable radial sealing according to an adjustment of the diameter of the surface, the membrane (1700, 1800) sealingly connecting the end segments (1106, 1206) of one of the sets (1100, 1200) of end segments to the carrier (1310, 1410) which is common to the end segments of this assembly.

4. Drum (1000) according to the preceding claim, wherein the membrane (1700, 1800) comprises annular folds (1710) forming bellows and radial folds (1720) distributed around the annular folds and extending to a periphery of the membrane.

The drum (1000) according to any one of the preceding claims, wherein the second sealing connection means comprise an axially deformable axial sealing member (1900) as a function of an adjustment of the distance between the first (1310) and second (1410) supports and sealingly connecting the first and second supports.

6. Drum (1000) according to the preceding claim, wherein the axial sealing member (1900) comprises telescopic tubes (1901, 1902, 1903, 1904, 1905, 1906) sliding axially between them according to the setting of the distance between the first (1310) and second (1410) supports.

The drum (1000) according to claim 5 or 6, wherein the members (1950, 1310, 1410) for adjusting the distance between the first and second supports and the surface diameter adjusting members (1980, 1600, 1400, 1450) each comprise an endless screw (1950, 1980), the two screws extending axially through the axial sealing member (1900).

A drum (1000) according to any one of claims 2 to 7, wherein the surface diameter adjusting members (1980, 1600, 1400, 1450) (1106, 1506, 1206) comprise first and second profiles Cams (1400) for cooperating respectively with first and second members (1450) for tracking said profiles respectively carried by the first and second sets (1100, 1200) of end segments (1106, 1206), the first and second second cam profiles (1400) being respectively carried by first and second cams (1600), the two cams being movable in a direction parallel to Γ axis (X), the first and second cam profiles (1400) respectively transforming a displacement first and second cams (1600) in radial displacement respectively of the first and second end segment assemblies (1100, 1200) (1106, 1206).

9. Drum (1000) according to any one of the preceding claims, wherein the members (1950) for adjusting the distance between the first (1310) and second (1410) supports comprise relative axial displacement members of the first and second supports.

The drum (1000) according to any one of claims 2 to 9, further comprising a set of central segments (1506) forming a central portion of the surface (1106, 1506, 1206), each central segment (1506) being carried by at least one axial rod (1002) slidably mounted on two end segments (1106, 1206).

11. Drum (1000) according to the preceding claim taken in combination with claim 3, wherein the membrane (1700, 1800) has at least one passage opening of the axial rod (1002).

A drum (1000) according to any one of claims 2 to 11, wherein the first (1100) and second (1200) sets of end segments (1106, 1206) bear respectively first (1111) and second ( 1112) annular grooves respectively positioning first and second rods.

A drum (1000) according to any one of claims 2 to 12, wherein within one of the end segment assemblies (1100, 1200), two circumferentially adjacent segments (1106, 1108) have complementary edges. with teeth and crenels.