PROCESS AND APPARATUS FOR PRODUCING TYRES FOR VEHICLE WHEELS

Abstract

In the production of tyres for vehicle wheels in which at least one colored label (200) is provided on at least one of the sidewalls of the tyre, a green tyre is arranged inside a vulcanization mold comprising a first half-shell (50), a second half-shell opposite to the first half-shell (50) and a crown of circumferential sectors configured to air-tightly couple with the first half-shell (50) and with the second half-shell when the vulcanization mold is closed. Each label (200) comprises a layer of colored cross-linkable elastomeric material. Each label (200) is arranged in a predetermined position on a first support surface (50a) defined in at least one of the aforementioned first and second half-shell. The green tyre is arranged inside the vulcanization mold so that one of the sidewalls of the green tyre rests on such a support surface (50a). The mold is then closed and the co-vulcanization of the green tyre and of the label(s) (200) inside the vulcanization mold starts, holding in position the labels (200) on the first support surface (50a) during at least one initial part of the vulcanization.

Claims

1-21. (canceled)

22. A process for producing tyres for vehicle wheels comprising: building a green tyre comprising a carcass structure, a tread band arranged in a radially outer position with respect to the carcass structure and a pair of sidewalls associated with the carcass structure on opposite sides with respect to an equatorial plane (M-M) of the green tyre; providing a vulcanization mold comprising a first half-shell, a second half-shell opposite the first half-shell, and a crown of circumferential sectors, wherein the circumferential sections are configured to air-tightly couple with the first half-shell and second half-shell when the vulcanization mold is closed; arranging one or more label in a predetermined position on a first support surface defined in at least one of the first half-shell and second half-shell, wherein the first support surface having a predetermined first surface profile and the one or more label comprises a layer of colored cross-linkable elastomeric material; holding in position the one or more label on the first support surface; arranging the green tyre inside the vulcanization mold wherein the sidewalls of the green tyre rests on the first support surface; closing the vulcanization mold; and co-vulcanizing the green tyre and the one or more label inside the vulcanization mold, wherein at least one initial part of the co-vulcanization is carried out while the one or more label is held in position on the first support surface.

23. The process according to claim 22, wherein the one or more label comprises a support film of plastic material associated with the layer of colored cross-linkable elastomeric material.

24. The process according to claim 23, wherein the one or more label comprises a bi-adhesive film associated with the support film on the opposite side with respect to the layer of colored cross-linkable elastomeric material, and wherein holding in position the one or more label on the first support surface comprises attaching the one or more label to the first support surface through the bi-adhesive film.

25. The process according to claim 22, wherein the vulcanization mold comprises a first label holding device acting on the first support surface, and wherein holding in position the one or more label on the first support surface comprises activating the first label holding device.

26. The process according to claim 25, further comprising deactivating the first label holding device when a pressure greater than, or equal to, 1 bar has been reached inside the vulcanization mold.

27. The process according to claim 22, wherein arranging the one or more label on the first support surface comprises: arranging the one or more label on a second support surface defined in a label transfer member, wherein the second support surface has a second surface profile with a shape matching the shape of the first surface profile; holding in position the one or more label on the second support surface through a second label holding device associated with the label transfer member and acting on the second support surface; moving the label transfer member towards the first support surface while the second label holding device is active; coupling the label transfer member with the first support surface with a shape coupling between the first surface profile and the second surface profile; deactivating the second label holding device; and moving the label transfer member away from the first support surface leaving the one or more label on the first support surface.

28. The process according to claim 27, wherein the second label holding device comprises a second vacuum suction device.

29. The process according to claim 27, wherein the vulcanization mold comprises a first label holding device acting on the first support surface and wherein holding in position the one or more label on the first support surface comprises activating the first label holding device, wherein the process comprises, after having coupled the label transfer member with the first support surface and before deactivating the second label holding device, activating the first label holding device.

30. The process according to claim 29, further comprising, before ending the co-vulcanization of the green tyre and of the one or more label, deactivating the first label holding device.

31. The process according to claim 27, wherein the vulcanization mold comprises a first label holding device acting on the first support surface, and wherein holding in position the one or more label on the first support surface comprises activating the first label holding device, wherein the first label holding device comprises a first vacuum suction device.

32. The process according to claim 22, further comprising, before arranging the one or more label on the first support surface, partially pre-vulcanizing the at one or more label.

33. An apparatus for producing tyres for vehicle wheels, comprising: a vulcanization mold comprising a first half-shell, a second half-shell opposite to the first half-shell, and a crown of circumferential sectors, wherein the circumferential sections are configured to air-tightly couple with the first half-shell and second half-shell when the vulcanization mold is closed, wherein at least one of the first half-shell and second half-shell comprises a first support surface configured to receive the one or more label and the one or more label comprises a layer of colored cross-linkable elastomeric material, and wherein the first support surface has a predetermined first surface profile; and a first label holding device configured to hold the one or more label on the first support surface.

34. The apparatus according to claim 33, wherein the first label holding device is connected to the first support surface.

35. The apparatus according to claim 34, wherein the first support surface comprises a plurality of first holes and the first label holding device comprises a first vacuum suction device connected to the plurality of first holes.

36. The apparatus according to claim 35, wherein the first support surface comprises a plurality of first label positioning areas, each for a respective label and each comprising a plurality of respective first holes, and wherein the first label holding device comprises a plurality of first vacuum suction devices, each connected to a predetermined number of holes of the respective first holes.

37. The apparatus according to claim 33, further comprising: a label transfer member comprising a second support surface having a second surface profile with a shape matching the shape of the first surface profile, wherein the label transfer member is movable between a position distal from the first support surface and a position proximal to the first support surface; wherein the label transfer member comprises a second label holding device configured to hold the one or more label on the second support surface (60a) during the movement of the label transfer member from the distal position to the proximal position.

38. The apparatus according to claim 37, wherein the second support surface comprises a plurality of second holes and the second label holding device comprises a second vacuum suction device.

39. The apparatus according to claim 38, wherein each of the second holes is connected to a respective second vacuum suction device.

40. The apparatus according to claim 38, wherein the second support surface comprises a plurality of second label positioning areas, each for a respective label and each comprising a plurality of respective second holes.

41. The apparatus according to claim 37, further comprising a coupling device configured to define a single mutual coupling position between the label transfer member and the first support surface.

42. The apparatus according to claim 41, wherein the coupling device comprises a pin associated with the label transfer member and the vulcanization mold, and a recess formed on the label transfer member and the vulcanization mold and configured to receive the pin.

Description

DESCRIPTION OF THE FIGURES

[0132] Further features and advantages of the present invention will become clearer from the following detailed description of a preferred embodiment thereof, made with reference to the attached drawings.

[0133] In such drawings:

[0134] FIG. 1 is a schematic view in partial half cross section of a portion of a tyre produced with the process and the apparatus of the present invention;

[0135] FIG. 2 is an example schematic side view of a tyre produced in accordance with the present invention;

[0136] FIG. 2a is an enlarged example schematic side view of a colored label provided in the tyre of FIG. 2;

[0137] FIG. 3 is a schematic view of a cross section of an apparatus for producing tyres in accordance with the present invention, in an operative configuration thereof;

[0138] FIG. 4 is a schematic view of a cross section of two constructive components of the apparatus of the present invention in a first operative position;

[0139] FIGS. 5 and 6 are schematic half cross section views of the constructive components of FIG. 4 in two different operative positions;

[0140] FIG. 7 is a schematic perspective view of one of the two constructive components of FIG. 4;

[0141] FIG. 8 is a schematic perspective view of the other of the two constructive components of FIG. 4.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0142] For the sake of simplicity, FIG. 1 shows only a part of an embodiment of a tyre 100 in accordance with the present invention, the remaining part, which is not shown, being substantially identical and being arranged symmetrically with respect to the equatorial plane M-M of the tyre.

[0143] The tyre 100 shown in FIG. 1 is, in particular, an embodiment of a tyre for four-wheeled vehicles.

[0144] Preferably, the tyre 100 is an HP or UHP tyre for sports and/or high or ultra-high performance automobiles.

[0145] In FIG. 1 “a” indicates an axial direction, “c” indicates a radial direction, “M-M” indicates the equatorial plane of the tyre 100 and “R-R” indicates the rotation axis of the tyre 100.

[0146] The tyre 100 comprises at least one support structure 100a and, in radially outer position with respect to the support structure 100a, a tread band 109 in elastomeric material.

[0147] The support structure 100a comprises a carcass structure 101, in turn comprising at least one carcass layer 111.

[0148] Hereinafter, for the sake of simplicity of presentation, reference will be made to an embodiment of the tyre 100 comprising a single carcass layer 111. However, it should be understood that what is described has analogous application in tyres comprising more than one carcass layer.

[0149] The carcass layer 111 has axially opposite end edges engaged with respective annular anchoring structures 102, called bead cores, optionally associated with an elastomeric filler 104. The area of the tyre 100 comprising the bead core 102 and the possible elastomeric filler 104 forms an annular reinforcing structure 103 called “bead structure” and intended to allow the tyre 100 to be anchored on a corresponding mounting rim, not shown.

[0150] The carcass layer 111 comprises a plurality of reinforcing cords 10′ coated with an elastomeric material or incorporated in a matrix of cross-linked elastomeric material.

[0151] The carcass structure 101 is of the radial type, i.e. the reinforcing cords 10′ are on planes comprising the rotation axis R-R of the tyre 100 and substantially perpendicular to the equatorial plane M-M of the tyre 100.

[0152] Each annular reinforcing structure 103 is associated with the carcass structure 101 through folding back (or turning) of the opposite end edges of the at least one carcass layer 111 around the bead core 102 and the possible elastomeric filler 104, so as to form the so-called turnings 101a of the carcass structure 101.

[0153] In an embodiment, the coupling between carcass structure 101 and annular reinforcing structure 103 can be made through a second carcass layer (not shown in FIG. 1) applied in a radially outer position with respect to the carcass layer 111.

[0154] An anti-abrasion strip 105 is arranged at each annular reinforcing structure 103 so as to surround the annular reinforcing structure 103 along the axially inner, axially outer and radially inner areas of the annular reinforcing structure 103, thus being arranged between the latter and the rim of the wheel when the tyre 100 is mounted on the rim. Such an anti-abrasion strip 105 may, however, not be provided.

[0155] The support structure 100a comprises, in a radially outer position with respect to the carcass structure 101, a crossed belt structure 106 comprising at least two belt layers 106a, 106b arranged radially juxtaposed over one another.

[0156] The belt layers 106a, 106b comprise a plurality of reinforcing cords 10a, 10b, respectively. Such reinforcing cords 10a, 10b have an orientation inclined with respect to the circumferential direction of the tyre 100, or to the equatorial plane M-M of the tyre 100, by an angle comprised between 15° and 45°, preferably between 20° and 40°. For example, such an angle is equal to 30°.

[0157] The support structure 100a can also comprise a further belt layer (not shown) arranged between the carcass structure 101 and the radially innermost belt layer of the aforementioned belt layers 106a, 106b and comprising a plurality of reinforcing cords having an orientation with respect to the circumferential direction of the tyre 100, or to the equatorial plane M-M of the tyre 100, inclined by an angle equal to 90°.

[0158] The support structure 100a can also comprise a further belt layer (not shown) arranged in a radially outer position with respect to the radially outermost belt layer of the aforementioned belt layers 106a, 106b and comprising a plurality of reinforcing cords having an orientation with respect to the circumferential direction of the tyre 100, or to the equatorial plane M-M of the tyre 100, inclined by an angle comprised between 20° and 70°.

[0159] The reinforcing cords 10a, 10b of one belt layer 106a, 106b are parallel to one another and have a crossed orientation with respect to the reinforcing cords of the other belt layer 106b, 106a.

[0160] In ultra-high performance tyres, the belt structure 106 may be a turned crossed belt structure. Such a belt structure is made by arranging at least one belt layer on a support element and turning the opposite lateral end edges of said at least one belt layer. Preferably, at first a first belt layer is arranged on the support element, then the support element is radially expanded, then a second belt layer is arranged on the first belt layer and finally the opposite axial end edges of the first belt layer are turned on the second belt layer to at least partially cover the second belt layer, which is the radially outermost one. In some cases, a third belt layer can be arranged on the second belt layer. Advantageously, the turning of the axially opposite end edges of a belt layer on another belt layer arranged in a radially outer position imparts greater reactivity and responsiveness to the tyre when entering a bend.

[0161] The support structure 100a comprises, in a radially outer position with respect to the crossed belt structure 106, at least one zero-degree reinforcing layer 106c, commonly known as “zero degrees belt”. It comprises reinforcing cords 10c oriented in a substantially circumferential direction. Such reinforcing cords 10c thus form an angle of a few degrees (typically less than 10°, for example comprised between 0° and 6°) with respect to the equatorial plane M-M of the tyre 100.

[0162] The tread band 109 made of elastomeric material, like other semi-finished products making up the tyre 100, is applied in a radially outer position with respect to the zero-degree reinforcing layer 106c. Respective sidewalls 108 made of elastomeric material are also applied onto the opposite side surfaces of the carcass structure 101, in an axially outer position with respect to the carcass structure 101 itself. Each sidewall 108 extends from one of the lateral edges of the tread band 109 up to the respective annular reinforcing structure 103.

[0163] The anti-abrasion strip 105, if provided, extends at least up to the respective sidewall 108.

[0164] In some specific embodiments, such as the one illustrated and described here, the rigidity of the sidewall 108 can be improved by providing a stiffening layer 120, generally known as “flipper” or additional strip-shaped insert, which has the function of increasing the rigidity and integrity of the annular reinforcing structure 103 and of the sidewall 108.

[0165] The flipper 120 is wound around a respective bead core 102 and the elastomeric filler 104 so as to at least partially surround the annular reinforcing structure 103. In particular, the flipper 120 surrounds the annular reinforcing structure 103 along the axially inner, axially outer and radially inner areas of the annular reinforcing structure 103.

[0166] The flipper 120 is arranged between the turned end edge of the carcass layer 111 and the respective annular reinforcing structure 103. Usually, the flipper 120 is in contact with the carcass layer 111 and the annular reinforcing structure 103.

[0167] In some specific embodiments, like the one illustrated and described here, the annular reinforcing structure 103 may also comprise a further stiffening layer 121 that is generally known with the term “chafer”, or protective strip, and which has the function of increasing the rigidity and integrity of the annular reinforcing structure 103.

[0168] The chafer 121 is associated with a respective turned end edge of the carcass layer 111 in an axially outer position with respect to the respective annular reinforcing structure 103 and extends radially towards the sidewall 108 and the tread band 109.

[0169] The flipper 120 and the chafer 121 comprise reinforcing cords 10d (in the attached figures those of the flipper 120 are not visible) coated with an elastomeric material or incorporated in a matrix of cross-linked elastomeric material.

[0170] The tread band 109 has, in a radially outer position, a rolling surface 109a intended to come into contact with the ground. Circumferential grooves (not shown in FIG. 1) are formed on the rolling surface 109a, said grooves being connected by transversal notches (not shown in FIG. 1) so as to define a plurality of blocks of various shapes and sizes (not shown in FIG. 1) on the rolling surface 109a.

[0171] An underlayer 107 is arranged between the crossed belt structure 106 and the tread band 109.

[0172] In some specific embodiments, like the one illustrated and described here, a strip 110 consisting of elastomeric material, commonly known as “mini-sidewall”, can optionally be provided in the connection area between the sidewalls 108 and the tread band 109. The mini-sidewall 110 is generally obtained through co-extrusion with the tread band 109 and allows an improvement of the mechanical interaction between the tread band 109 and the sidewalls 108.

[0173] Preferably, an end portion of the sidewall 108 directly covers the lateral edge of the tread band 109.

[0174] In the case of tubeless tyres, a layer of elastomeric material 112, generally known as “liner”, can also be provided in a radially inner position with respect to the carcass layer 111 to provide the necessary impermeability to the inflation air of the tyre 100.

[0175] As shown in FIG. 2, on the outer surface of at least one of the two sidewalls 108 a plurality of colored labels 200 is provided. In the specific case illustrated here, the tyre 100 comprises four labels 200, each one being arc-shaped; two of such labels are identical and diametrically opposite, one has a circumferential dimension smaller than that of the aforementioned two and another has a circumferential dimension which is intermediate with respect to those of the aforementioned labels.

[0176] Each label 200 can cover only a part of the sidewall 108 of the tyre 100, like for example in the case illustrated here in which the label 200 comprises drawings, letters, logos, trademarks, decals, or it can cover almost the totality of the sidewall 108, like for example in the case in which the label 200 comprises a layer arranged, in whole or in part, along the cross section of the sidewall 108.

[0177] With reference to FIG. 2a, each label 200 is prepared by applying a layer of colored cross-linkable elastomeric material 201 to a support film 202.

[0178] The layer of elastomeric material 201 comprises (i) 100 phr of elastomeric polymer comprising from 30 to 70 phr of natural and/or synthetic isoprene rubber, and from 30 to 70 phr of a rubber selected from butyl rubber, halogen-butyl rubber, butadiene rubber, styrene-butadiene rubber and mixtures thereof, (ii) from 5 to 120 phr of at least one reinforcing filler, (iii) at least 0.5 phr of at least one coloring agent, (iv) preferably, a non-staining ozone protection system and v) from 0.5 phr to 10 phr of at least one cross-linking agent.

[0179] The aforementioned layer of elastomeric material 201 has physical-chemical characteristics compatible with those of the elastomeric material of the sidewalls 108. The latter comprises (i) at least one elastomeric diene polymer, and (ii) an ozone protection system.

[0180] The layer of elastomeric material 201 has a thickness preferably comprised between 0.1 mm and 0.8 mm, more preferably between 0.2 mm and 0.6 mm, even more preferably between 0.3 mm and 0.5 mm.

[0181] The support film 202 is made of a plastic material capable of withstanding temperatures between 140° C. and 200° C.

[0182] Such a plastic material is selected from the group comprising polyolefin, like polyethylene (PE) (possibly cross-linked) and polypropylene (PP), polyesters, like polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamides, polyimides, perfluorinated polymers, like polytetrafluoroethylene (PTFE), and polyurethanes (PU), more preferably polyethylene terephthalate (PET) or polyamides, like, for example Nylon 6 or Nylon 66.

[0183] The support film 202 has a thickness preferably comprised between 0.05 mm and 0.70 mm, more preferably between 0.10 mm and 0.50 mm, even more preferably between 0.20 mm and 0.30 mm.

[0184] In some embodiments thereof, like for example the one illustrated schematically in FIG. 2a, the label 200 also comprises a bi-adhesive film 203.

[0185] Such a bi-adhesive film 203 is associated with the support film 202 on the opposite side with respect to the layer of elastomeric material 201 and has a thickness preferably comprised between 0.01 mm and 0.1 mm.

[0186] The bi-adhesive film 203 is such as to maintain an adequate adhesive capability in the aforementioned range of temperatures (140° C.-200° C.).

[0187] For example, a suitable adhesive film 203 can be the one commercialized by Ritrama S.p.A. with the name 4-GL2B-01228 Ultracrystalline Clear AP906 Permanent/AP906 Permanent PET30.

[0188] Each label 200 therefore has a total thickness comprised between 0.15 mm and 1.2 mm.

[0189] Each label 200 can comprise an anti-abrasion protective layer (not shown) arranged between the support film 202 and the layer of elastomeric material 201, such an anti-abrasion protective layer comprising cross-linked aliphatic polyurethanes.

[0190] A production cycle of the tyre 100 described above comprises, after a building process of a green tyre in which the various components of the tyre 100 are made and/or assembled, a molding and vulcanization process of the green tyre, aimed to define the structure of the tyre 100 according to a desired geometry, normally having a particular tread pattern.

[0191] The building of the green tyre can be carried out assembling its respective semi-finished products on a forming support by at least one assembly device.

[0192] In particular, on the forming support it is possible to build and/or assemble an inner sleeve comprising the carcass structure 101 of the tyre 100, the annular reinforcing structures 103 and the sidewalls 108. More in particular, the forming support firstly receives the possible liner 112. Then the carcass structure 101 is formed, by depositing the at least one carcass layer 111 and forming the opposite annular reinforcing structures 103. Thereafter, the sidewalls 108 and the anti-abrasion strip 105, if provided, are positioned.

[0193] In an auxiliary forming support it is possible to assemble an outer sleeve comprising the belt structure 106, the possible zero degree reinforcing layer 106c and the tread band 109.

[0194] Thereafter, the aforementioned outer sleeve is arranged in a coaxially centered and radially outer position with respect to the aforementioned inner sleeve and the green tyre thus assembled is shaped according to a toroidal configuration through radial dilation of the inner sleeve, so as to associate the radially outer surface of the inner sleeve against the radially inner surface of the outer sleeve.

[0195] The green tyre thus shaped is subsequently subjected to a molding and vulcanization treatment aimed to determine the structural stabilization of the tyre by cross-linking of the elastomeric material as well as to impress a desired tread pattern on the tread band 109 and to impress the labels 200 at the sidewalls.

[0196] For this purpose, the green tyre is arranged in a molding cavity 1a defined inside a vulcanization mold 1 and shaped according to the geometric configuration of the outer surfaces of the tyre 100 to be obtained.

[0197] FIG. 3 shows the tyre 100 in the final configuration thereof taken up inside the vulcanization mold 1 at the end of the molding and vulcanization operations.

[0198] In the vulcanization mold 1 a geometric axis Y is defined that preferably coincides, as shown in FIG. 3, with the rotation axis of the green tyre when the latter is inserted in the vulcanization mold 1 and with the rotation axis R-R of the tyre 100 obtained at the end of vulcanization.

[0199] The vulcanization mold 1 comprises a base block 2 from which a substantially cylindrical central body 3 having an axis coinciding with the axis Y projects at the top.

[0200] The central body 3 is preferably of the telescopic type, so that it can be adjusted in height so as to adapt it to green tyres of different sizes.

[0201] The base block 2 has a lower annular element 5 fixed to it, centered with respect to the cylindrical central body 3, on which the green tyre is rested when introduced into the vulcanization mold 1, as described hereinafter.

[0202] The vulcanization mold 1 further comprises a closure element 6 arranged above the lower annular element 5 and movable with respect to the latter between an open position of the vulcanization mold 1, at which the introduction of the green tyre in the molding cavity 1a takes place, and a closed position of the vulcanization mold 1, at which the molding and vulcanization operations begin.

[0203] The lower annular element 5 comprises an inner annular element 50, also called lower half-shell, and an outer annular element 51 arranged around the inner annular element 50 coaxially to the latter.

[0204] The lower half-shell 50 is configured to abut on a sidewall of the green tyre when the tyre 1 is rested on the lower annular element 5 of the vulcanization mold 1.

[0205] The closure element 6 has an upper annular element 7, also called upper half-shell, fixed to it. The latter is configured to abut on the other sidewall of the green tyre when the vulcanization mold 1 is closed.

[0206] The vulcanization mold 1 also comprises a plurality of circumferential sectors 8 configured to air-tightly abut to the lower half-shell 50 and to the upper half-shell 7 when the vulcanization mold 1 is closed.

[0207] The circumferential sectors 8 circumscribe the molding cavity 1a and generally carry a plurality of forming projections (not visible in FIG. 3) configured to create in the tread band a series of notches and grooves 109 suitably arranged according to a desired “tread pattern”.

[0208] Preferably, the lower and upper half-shells 50, 7 are removable so as to be possibly replaced with half-shells having different diameter and surface profiles so that the remaining structural components of the vulcanization mold 1 can be used with tyres of different diameters and shapes.

[0209] Similarly, the circumferential sectors 8 are preferably removable so as to possibly be replaced with circumferential sectors having a different shape and tread pattern.

[0210] The surface shape of the lower and upper half-shells 50, 7, at least at a portion thereof, is substantially analogous to that of the sidewalls of the tyre 100.

[0211] As shown in greater detail in FIG. 7, the lower half-shell 50 comprises an upper surface 50a, also indicated here as “support surface” as it is intended to act as support for the labels 200 and for the green tyre during the vulcanization of the tyre 100.

[0212] The support surface 50a has a non-planar shape and a predetermined surface profile.

[0213] In the specific embodiment illustrated here, a plurality of label positioning areas 52 are defined on the aforementioned support surface 50a, each being configured to receive a respective label 200.

[0214] The label positioning areas 52 are preferably not recessed with respect to the first support surface 50a and each comprise a plurality of holes 53. In the attached figures, reference numeral 53 is associated with only some of the holes shown in the label positioning areas 52.

[0215] The holes 53 of each of the label positioning areas 52 are grouped so as to provide the respective label positioning area 52 with a shape which is substantially identical to the shape of the label 200 that it has to receive.

[0216] As shown in FIGS. 4-6, all of the holes 53 of each label positioning area 52 are connected to a respective suction device 55 adapted to create the vacuum (herein indicated as “vacuum suction device”).

[0217] With particular reference to FIG. 5, each vacuum suction device 55 comprises a plurality of suction channels 56 that connect the holes 53 of each label positioning area 52 to a respective suction chamber 57, which in turn is connected, through respective suction ducts 58, 59, to a respective vacuum pump (not shown) housed in the base block 2.

[0218] The suction channels 56 can be formed on suitable inserts (not shown) by removal of material. Such channels have a diameter comprised between 0.1 mm and 0.8 mm each and from 3 to 20 channels per cm.sup.2 are provided.

[0219] Alternatively, the aforementioned channels can consist of lamellar microslots having a thickness comprised between 0.05 mm and 0.8 mm and arranged with a pitch comprised between 0.1 mm and 3 mm.

[0220] Preferably, the vacuum suction devices 55, once activated, generate a label holding pressure greater than, or equal to, 1 kPa, preferably greater than, or equal to, 2 kPa, more preferably greater than, or equal to, 5 kPa, even more preferably greater than, or equal to, 10 kPa, even more preferably greater than, or equal to, 20 kPa.

[0221] Preferably, the label holding pressure is lower than, or equal to, about 50 kPa.

[0222] The positioning of the labels 200 in the label positioning areas 52 defined on the support surface 50a of the lower half-shell 50 of the vulcanization mold 1 preferably follows a prior positioning of the labels 200 in suitable label positioning areas 65 provided on a label transfer member 60 movable between a distal position away from the lower half-shell 50 and a proximal position close to the lower half-shell 50.

[0223] The label positioning areas 65 are defined on a support surface 60a defined in the label transfer member 60 and having a profile with a shape matching the shape of the profile of the support surface 50a.

[0224] The label transfer member 60 is configured to couple with the lower half-shell 50 through a shape coupling between support surface 60a and support surface 50a.

[0225] The movement of the label transfer member 60 from the aforementioned distal position to the aforementioned proximal position can take place for example through manual gripping by two operators of four grip elements 80 suitably provided on the label transfer member 60. As shown in FIG. 4, such grip elements 80 extend from an upper surface of the label transfer member 60, such a surface being opposite to the aforementioned support surface 60a.

[0226] When the label transfer member 60 is in the aforementioned distal position, the labels 200 are arranged on respective label positioning areas 65 suitably provided on the support surface 60a defined in the label transfer member 60, whereas when the label transfer member 60 is in the aforementioned proximal position the labels 200 are transferred from the label transfer member 60 to the label positioning areas 52 provided in the lower half-shell 50 of the vulcanization mold 1.

[0227] As shown in FIGS. 4 and 5, the mutual coupling between the label transfer member 60 and the lower half-shell 50 is achieved and guided through a suitable coupling device 90 that, in the embodiment illustrated here, comprises a pin 91 associated with the label transfer member 60 and a recess 92 formed in the lower half-shell 50.

[0228] The pin 91 extends from the label transfer member 60 on the opposite side with respect to the grip elements 80.

[0229] In the embodiment illustrated here, the recess 92 is formed at the interface between the lower half-shell 50 and the base block 2.

[0230] The recess 92 has a top portion 93 that is flared to facilitate the insertion of the pin 91 therein.

[0231] During the movement from the aforementioned distal position to the aforementioned proximal position, the labels 200 arranged in the label positioning areas 65 of the label transfer member 60 are held in position through suitable label holding devices 70.

[0232] In the embodiment illustrated here, such label holding devices 70 comprise vacuum suction devices 71, in particular vacuum pumps, each connected to a respective hole 66 formed on the support surface 60a of the label transfer member 60 at a respective label positioning area 65.

[0233] In the attached figures, the reference numerals 70 and 71 are associated with only some of the label holding devices and of the vacuum suction devices shown, whereas reference numerals 66 are associated with only some of the aforementioned holes.

[0234] As shown in FIG. 6, each label holding device 70 can also comprise a respective suction cup 71 projecting from the support surface 60a, such a suction cup 71 being arranged at a respective hole 66.

[0235] FIG. 8 shows that each label positioning area 65 comprises a plurality of holes 66, each associated with a respective label holding device 70. In FIG. 8 the suction cups 71 have been removed to make the aforementioned holes 66 easier to see.

[0236] Once the coupling between the label transfer member 60 and the lower half-shell 50 has been achieved, the vacuum suction devices 71 are deactivated so that the labels 200 can pass from the label positioning areas 65 to the label positioning areas 52 provided in the lower half-shell 50.

[0237] In the embodiments in which the labels 200 are not provided with the bi-adhesive film 203, before deactivating the vacuum suction devices 71 the vacuum activation devices 55 are activated.

[0238] In the embodiments in which the labels 200 are provided with the bi-adhesive film 203, the lower half-shell 50 of the vulcanization mold 1 can be without the aforementioned holes 53. In this case indeed the passage of the labels from the label positioning areas 65 to the label positioning areas 52 preferably takes place after having exerted a slight pressure of the label transfer member 60 on the lower half-shell 50 and always after having deactivated the vacuum suction devices 71, by the effect of the adhesive action exerted on the label positioning areas 52 by the bi-adhesive film 203. Such pressure may however not be necessary since it is actually exerted due to the weight of the label transfer member 60.

[0239] In all the embodiments, preferably, the label transfer member 60 is left rested on the lower half-shell 50 for about a couple of minutes.

[0240] Subsequently, the label transfer member 60 can be taken away from the lower half-shell 50, as shown in FIG. 6. For this purpose, the label transfer member 60, without the labels 200, is taken through the grip elements 80 and transferred into a distal position with respect to the lower half-shell 50.

[0241] It is thus possible to proceed to the positioning of the green tyre inside the molding cavity 1a of the vulcanization mold 1.

[0242] The green tyre is arranged by resting its sidewall 108 on which the labels 200 have to be applied on the lower half-shell 50, the closure element 6 is closed by making contact with the other sidewall 108 of the green tyre and the circumferential sectors 8 are brought into contact with the tread band 109 of the green tyre, air-tightly abutting on the low and upper half-shells 50, 7.

[0243] At this point it is possible to proceed with the vulcanization of the tyre 100. During such vulcanization the vulcanization of the elastomeric layer 201 of the labels 200 also takes place.

[0244] An initial part of the vulcanization is carried out while the vacuum suction devices 55 are kept activated, and thus while the labels 200 are held in the respective label positioning areas 52. This happens for a time period no longer than 10 minutes from the start of the co-vulcanization, more preferably no longer than 9 minutes, even more preferably no longer than 8 minutes from the start of the co-vulcanization, and in any case when the pressure inside the vulcanization mold is equal to 1.5 bar, more preferably to 1 bar.

[0245] Once this time period has passed the vacuum suction devices 55 can be deactivated and the vulcanization can proceed until the completion thereof.

[0246] Before being arranged in the label positioning areas 65 the labels 200 can be partially pre-vulcanized and shaped by removal of material so as to give them the desired shape.

[0247] For example, the pre-vulcanization of the labels 200 is carried out for a period of at least 1 hour, preferably at least 2 hours, at a temperature equal to or lower than 120° C., preferably equal to or lower than 110° C., but equal to or greater than 40° C., preferably greater than 50° C., and more preferably greater than 60° C.

[0248] Once the vulcanization is completed, the vulcanization mold 1 is opened and the vulcanized tyre 100 is removed from the vulcanization mold 1.

[0249] Finally, the support films 202 are removed from the sidewall 108 of the tyre 100 at each of the labels 200.

[0250] The present invention has been described with reference to some preferred embodiments. Different modifications can be made to the embodiments described above, whilst still remaining within the scope of protection of the invention, defined by the following claims.