The present invention relates to a tyre supporting system. TECHNICAL FIELD

In the tyre industry, handling and storing tyres both green tyres for curing, and cured tyres for distribution, processing, or retreading - pose numerous problems . This applies in particular to green tyres, but also to others in proportion to the size and weight of the tyres, and the problems posed derive from harmful deformation of the carcasses caused by handling and storing the tyres on edge or laid flat in stacks. To solve these problems, tyre supporting systems have been proposed, as, for example, in JP-A-11123773 and JP-A-2007098935, comprising a tubular support which is inserted through a toroidal body of a tyre comprising two beads a given distance apart, and comprises a tubular body; two mechanical bead locking devices located said distance apart on the tubular body, and each of which acts on a radially inner surface of a respective bead to lock the tyre axially and radially to the tubular body; and pneumatic means for feeding air into the tyre . BACKGROUND ART

Known supporting systems of this type employ segmental mechanical bead locking devices which, besides being complicated and expensive in themselves, fail to keep the tyre sealed and must be equipped with an additional sealing device. The inflation device is located inside the tyre, normally comprises two bladders designed to cooperate with the inner surface of the tyre and equipped with an inflation system, and so makes the supporting system even more complicated and expensive.

Mainly in view of the fact that, pending curing and/or assembly, each tyre on the production line must be equipped with a respective supporting system, attempts have been made to reduce cost by proposing a supporting system, as for example in JP-A-59081156, in which the bead locking device is pneumatic and comprises two bladders, each of which is positioned radially inwards of a respective bead, and, when inflated, locks the bead radially and at the same time keeps the tyre sealed.

This type of supporting system however, is extremely unstable, is totally unsuitable for use on large tyres, and is never used, except for short periods of time, without an outer support for supporting and holding the tyre in a stable position on the supporting system. DISCLOSURE OF INVENTION It is an object of the present invention to provide a tyre supporting system that is structurally stable, relatively cheap to produce, and designed to eliminate the aforementioned drawbacks . According to the present invention, there is provided a tyre supporting system as claimed in Claim 1 and preferably in any one of the following Claims depending directly or indirectly on Claim 1. BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a schematic, partly sectioned side view of a preferred embodiment of the tyre supporting system according to the present invention;

Figure 2 shows a schematic, larger-scale axial section of a detail in Figure 1;

Figures 3 and 4 show respective variations of the Figure 1 supporting system, each comprising the Figure 2 detail. BEST MODE FOR CARRYING OUT THE INVENTION

IA in Figure 1 indicates as a whole a tyre supporting system comprising a tubular support 2 for supporting a toroidal body 3, which, in the example shown, is defined by a green tyre and comprises a central tread portion 4; two sidewalls 5 on opposite sides of central tread portion 4; and two beads 6, each defining a free end portion of the relative sidewall 5. As shown more clearly in Figure 2, tubular support 2 comprises a cylindrical sleeve 7 bounded internally by a cylindrical surface 8 with an axis 9, and externally by a cylindrical surface coaxial with axis 9 and having two annular recesses 10a, 10b, which define a central annular rib 11 on sleeve 7, and are closed axially outwards by respective rings 12 fixed removably to sleeve 7. At one end, sleeve 7 has an annular inner flange 13 that acts as an axial supporting surface for an air dispenser 14 comprising a tube 15 fitted coaxially with axis 9 inside sleeve 7. Tube 15 has a cylindrical outer surface 16 mating in fluidtight manner with cylindrical surface 8 of sleeve 7, and has an annular axial end surface resting against inner flange 13, to which tube 15 is connected integrally by a number of screws 17 fitted through inner flange 13 and parallel to axis 9.

At least some of screws 17 have respective rings 18 projecting outwards of inner flange 13 and for the purpose explained below.

Air dispenser 14 comprises an air circuit 19 in turn comprising a conduit 20 parallel to axis 9, formed in the thickness of tube 15, and extending from an inlet valve 21 at the opposite end of tube 15 to that connected to inner flange 13. The inner end of conduit 20 is connected to a radial conduit 22 connecting air circuit 19 in fluidtight manner to a further radial conduit 23 formed through sleeve 7 at central rib 11. Air dispenser 14 comprises two further air circuits 24, 25, each of which comprises a conduit 26 parallel to axis 9, formed in the thickness of tube 15, and extending from a respective inlet valve 27 at the opposite end of tube 15 to that connected to inner flange 13. The inner end of each conduit 26 is connected to a respective radial conduit connecting relative air circuit 24, 25 in fluidtight manner to a further radial conduit 28 formed through sleeve 7 and which comes out at the bottom of a respective annular groove 29 formed in the bottom of relative recess 10a, 10b and extending about axis 9, between two seals.

Recesses 10a and 10b are engaged by respective tubular slides 30a and 30b, which are shorter in length than recesses 10a and 10b, are mounted to slide along sleeve 7, and are fixed adjustably to sleeve 7 by respective radial pins, so as to be symmetrical with respect to a central plane 31 perpendicular to axis 9. Each tubular slide 30a, 30b is bounded externally by a cylindrical surface 32, in which are formed two annular grooves 33 and 34. Groove 33 is located substantially centrally, whereas groove 34 is deeper than groove 33 and formed in an end portion of groove 33 facing a respective axial end of tubular body 2. The respective bottom surfaces of annular grooves 33 and 34 have respective annular seats for respective fasteners of respective bladders 35, each of which communicates with respective annular groove 29 via a respective radial conduit 36 formed through the centre of tubular slide 30a, 30b, at respective annular groove 33.

To ensure each radial conduit 36 communicates with relative annular groove 29, regardless of the axial position of relative tubular slide 30a, 30b, annular grooves 29 are formed centrally in the bottom of relative recesses 10a and 10b, and are wider than the difference between the width of each recess 10a, 10b and the width of relative tubular slide 30a, 30b.

As shown more clearly in Figure 2, each bladder 35 is an asymmetric controlled deformation bladder, and comprises a portion 37 with an outer annular stiffener

38; and a portion 39 fan-folded onto the bottom surface of relative annular groove 34.

Stiffener 38 is defined in known manner by a ring of rigid axial ribs embedded in a layer of elastomer material .

In actual use, tubular slides 30a and 30b are positioned so the end portions of annular grooves 33 adjacent to respective annular grooves 34 are spaced the same distance apart as beads 6 of toroidal body 3 to be supported; and toroidal body 3 is then fitted on, so beads 6 are positioned radially outwards of the relative said end portions.

Compressed air is then fed into bladders 35, which causes portions 37 to flex outwards; and, being substantially rigid and connected, at its end facing central plane 31, to relative tubular slide 30a, 30b, each portion 37 flexes into a cone shape and cooperates in fluidtight manner with the radially inner surface of relative bead 6. At the same time, the compressed air injected into bladders 35 expands portions 39 outwards, so that each forms a tubular bladder 40 outwards of relative bead 6 and of the wide end of relative cone- shaped portion 37. in other words, each tubular bladder 40 defines an annular projection or stop at the wide end of relative cone-shaped portion 37.

When compressed air is then fed along radial conduit 23 into toroidal body 3, beads 6 move in opposite directions along axis 9, lock onto the annular stops defined by relative tubular bladders 40, and are thus locked radially and axially with respect to relative tubular slides 30a and 30b.

As will be clear from the above description : tubular support 2 described is relatively straightforward and cheap to produce, by locking and sealing toroidal body 3 by means of two asymmetric controlled deformation bladders 35, with no mechanical devices required;

- tubular support 2 described is extremely stable, on account of the air injected into toroidal body 3, once bladders 35 are inflated, causing beads 6 to slide outwards along cone-shaped portions 37, and onto the annular stops defined by tubular bladders 40.

In connection with the above, it should be pointed out that, as they slide axially, beads 6 are pressed progressively more firmly against cone-shaped portions 37, which absorb substantially all the radial loads and large part of the axial loads, so bladders 40 serve simply as stops. And since stiffeners 38 are designed to withstand such stress without deformation, portions 37 prevent any parting movement of tubular bladders 40.

In other words, portions 37 act as axial ties which, ' if designed properly, are capable of locking a toroidal body 3 of any weight, and also ensuring sealing of toroidal body 3 regardless of the pressure of the air injected into it.

Tubular support 2 may either be used on its own as a supporting system for a toroidal body 3, or form part of a complex supporting system such as IA in Figure i, which is particularly suitable for supporting toroidal bodies 3 in the form of relatively large green tyres normally used for farming or earth moving machinery.

Supporting system IA comprises an upright 41, from the top end of which projects a shaft 42 having, and powered to rotate about, a horizontal axis 43. Shaft 42 has two flanges 44 smaller in diameter than the inside diameter of tube 15, and spaced apart by a distance greater than the length of sleeve 7. In actual use, tubular support 2 is fitted onto shaft 42 and kept rotating relatively slowly to prevent static radial deformation of toroidal body 3.

In the Figure 3 embodiment, tubular support 2 forms part of a supporting system IB particularly suitable for supporting toroidal bodies 3 in the form of relatively large green tyres as they are fed to a curing mold (not shown) .

Supporting system IB comprises a hoist 45 with a number of end cables 46, each of which is attached to a respective ring 18 to suspend supporting body 2 vertically from hoist 45 and insert supporting body 2 partly inside a toroidal body 3 resting on a horizontal surface, so that tubular slide 30a engages the top bead 6. When the relative bladder 35 is inflated, tubular support 2 engages toroidal body 3, so this can be lifted into a suspended position for insertion into the bottom half-mold (not shown) or a curing mold (not shown) . In this case, too, performance of portion 37 of bladder 35 as a reinforced tie enables supporting system Ib, if properly designed, to handle toroidal bodies 3 of any weight .

In the Figure 4 embodiment, tubular support 2 forms part of a supporting system 1C particularly suitable for supporting toroidal bodies 3 in the form of cured tyres for retreading.

Supporting system 1C comprises an upright 47, from the top end of which projects a spindle 48, which has a horizontal axis 49, fits inside tube 15, coaxially with axis 9, and is powered to rotate with tubular support 2 about axis 49.

All the supporting systems described may obviously feature a simplified version (not shown) of tubular support 2 designed for one toroidal body 3. In which case, tubular slides 30a, 30b are eliminated; annular grooves 33, 34 are formed directly in sleeve 7 as opposed to recesses 10a, 10b; and air dispenser 14 may be incorporated in sleeve 7 .