PROCESS AND APPARATUS FOR HANDLING GREEN TYRES FOR BICYCLES

Abstract

A green tyre (2) for bicycles is built, comprising at least one carcass ply (4) having axially opposite end flaps (4a) engaged with respective bead cores (5) and a tread band (6) applied in a radially outer position around said at least one carcass ply (4). The green tyre (2) removed from the building drum, is profiled so as to translate the tread band (6) in a radially outer direction with respect to the bead cores (5), so as to impart a cross-sectional convex profile to the tyre (2) in a radially outer direction. The profiled tyre is engaged by means of a transfer member (31) while the tyre itself is mechanically restrained so as to maintain at least partly said cross-sectional convex profile in the radially outer direction.

Claims

1-41. (canceled)

42. A process for handling green tyres for a bicycle, comprising: building a green tyre, wherein the green tyre comprises at least one carcass ply with axially opposite end flaps engaged with respective bead cores and a tread band applied in a radially outer position around the at least one carcass ply; arranging the green tyre around a profiling unit; profiling the green tyre by translating the tread band in a radially outer direction with respect to the bead cores to impart a cross-sectional convex profile to the tyre in a radially outer direction; and engaging the tyre by a transfer member with the green tyre mechanically restrained to at least partly maintain the cross-sectional convex profile in a radially outer direction.

43. The process as claimed in claim 42, wherein during the profiling, restoring the development of the tyre to a circular configuration around a geometric axis of rotation (X) thereof.

44. The process as claimed in claim 42, wherein during the profiling, centering the tyre with an axis of rotation (X) thereof coincident with a central geometric axis (Y) of a centring mandrel.

45. The process as claimed in claim 42, wherein profiling the green tyre comprises: positioning the tyre around a central geometric axis (Y) of a centring mandrel; and expanding a profiling member inside the tyre extending circumferentially around the central geometric axis (Y).

46. The process as claimed in claim 45, wherein profiling the green tyre further comprises: expanding the profiling member from a radially contracted condition, wherein the profiling member has at least one portion distant from a radially inner surface of the tire, to a radially expanded condition, wherein the profiling member operates against the radially inner surface of the tyre by exerting a thrust action in a substantially radial direction form the inside towards the outside.

47. The process as claimed in claim 45, wherein the profiling member comprises an expandable membrane concentrically fixed to the central geometric axis (Y).

48. The process as claimed in claim 45, wherein the profiling member comprises a plurality of sectors radially movable with respect to the central geometric axis (Y).

49. The process as claimed in claim 45, wherein profiling the green tyre further comprises, after expanding the profiling member, contracting the profiling member.

50. The process as claimed in claim 49, wherein following contracting the profiling member, separating the profiling member from a radially inner surface of the tyre.

51. The process as claimed in claim 50, wherein during profiling, expanding and contracting of the profiling member are cyclically repeated at least twice.

52. The process as claimed in claim 45, further comprising repeating the expanding step with progressively increasing intensity of the profiling member inside the tyre.

53. The process as claimed in claim 52, wherein repeating expanding and following one another within a time of less than about 30 seconds.

54. The process as claimed in claim 47, wherein expanding comprises feeding an operating fluid at a first pressure value in the expandable membrane.

55. The process as claimed in claim 54, wherein expanding further comprises feeding the operating fluid at a second pressure value, higher than the first pressure value, in the expandable membrane.

56. The process as claimed in claim 55, wherein the first pressure value ranges from about 10 kPa to about 150 kPa.

57. The process as claimed in claim 54, wherein expanding comprises feeding the operating fluid at the first pressure value, for a time ranging from about 1 second to about 25 seconds.

58. The process as claimed in claim 55, wherein the second pressure value ranges from about 10 kPa to about 150 kPa.

59. The process as claimed in claim 55, wherein expanding further comprises feeding the operating fluid at the second pressure value, for a time ranging from about 1 second to about 25 seconds.

60. The process as claimed in claim 42, wherein engaging the tyre by the transfer member comprises: coaxially positioning a gripping device carried by the transfer member around the tyre; and expanding the profiling member.

61. The process as claimed in claim 60, wherein the gripping device comprises gripping elements circumferentially distributed around a gripping axis (Z) and operatively activated against a radially outer surface of the tread band.

62. The process as claimed in claim 60, wherein the gripping device is axially positioned for arranging the gripping elements in a predetermined axial gripping position with respect to the tyre.

63. The process according to claim 61, wherein engaging the tyre with the transfer member is by attracting circumferentially along a radially outer surface of the tread band.

64. The process as claimed in claim 63, wherein attracting is exerted by a pneumatic suction action.

65. The process as claimed in claim 60, wherein attracting is exerted by a pneumatic suction and the pneumatic suction action is exerted by the gripping elements.

66. The process as claimed in claim 65, wherein the pneumatic suction action is activated when the tread band and the gripping elements are in mutual contact.

67. The process as claimed in claims 44, wherein the tyre is removed from the centring mandrel and transferred to a subsequent working station.

68. An apparatus for handling green tyres for a bicycle, wherein each green tyre comprises at least one carcass ply having axially opposite end flaps engaged with respective bead cores and a tread band applied in a radially outer position on the carcass ply, comprising: a profiling unit operatively engageable with the green tyre and activated for translating the tread band in a radially outer direction with respect to the bead cores to impart a cross-sectional convex profile to the green tyre in a radially outer direction; and a transfer member configured for engaging the green tyre while the green tyre is mechanically restrained by the profiling unit while at least partly maintaining the cross-sectional convex profile in a radially outer direction.

69. The apparatus as claimed in claim 68, wherein the profiling unit comprises: a centring mandrel having a central geometric axis (Y); and a radially expandable profiling member extending circumferentially around the central geometric axis (Y).

70. The apparatus as claimed in claim 69, wherein the centring mandrel comprises a coupling shank arranged concentrically to the central geometric axis (Y).

71. The apparatus as claimed in claim 69, wherein the profiling member comprises an expandable membrane.

72. The apparatus as claimed in claim 69, wherein the profiling member comprises a plurality of sectors radially movable with respect to the central geometric axis (Y).

73. The apparatus as claimed in claim 69, wherein the central geometric axis (Y) is arranged transversely with respect to a horizontal geometric plane.

74. The apparatus as claimed in claim 69, wherein the profiling unit further comprises axial positioning devices of the green tyre positioned along the central geometric axis (Y) of the centring mandrel.

75. The apparatus as claimed in claim 74, wherein each axial positioning device comprises a circumferential support with a circumferential supporting surface protruding in a radially outer direction with respect to the profiling member, and configured for supporting the tyre in laying relation at an axially outer edge thereof.

76. The apparatus as claimed in claim 75, wherein the circumferential support and the profiling member are reciprocally positionable along a direction parallel to the central geometric axis (Y).

77. The apparatus as claimed in claim 75, wherein the circumferential support comprises: a support ring slidably engaged with respect to the centring mandrel along the central geometric axis (Y); and elastically movable sheets fixed to the support ring and circumferentially distributed around the central geometric axis (Y) configured for defining the circumferential supporting surface.

78. The apparatus as claimed in claim 77, wherein the sheets are spaced apart from the central geometric axis (Y) by a greater extent than a maximum radius of the profiling unit with respect to the central geometric axis (Y) itself.

79. The apparatus as claimed in claim 77, wherein each sheet comprises an attachment portion fixed to the support ring and extending away from the latter parallel to the central geometric axis (Y), and a supporting portion extending transversely from one end of the attachment portion.

80. The apparatus as claimed in claim 68, wherein the transfer member comprises a driving group with a gripping device and the gripping device comprises gripping elements circumferentially distributed around a gripping axis (Z).

81. The apparatus as claimed in claim 80, wherein the gripping device comprises a tailstock coaxial to the gripping axis (Z) and engageable in shape coupling with a coupling shank.

82. The apparatus as claimed in claim 80, wherein the gripping elements comprise suction members activated to exert a pneumatic suction action against the green tyre engaged on the centring mandrel.

Description

[0118] Further features and advantages will become more apparent from the detailed description of a preferred but non-exclusive embodiment of a process and apparatus for handling green tyres for bicycle according to the present invention. Such a description is given hereinafter with reference to the accompanying drawings, provided only for illustrative and, therefore, non-limiting purposes, in which:

[0119] FIGS. 1 to 4 schematically show cross-sectional views of some operating steps designed to build a green tyre for bicycle;

[0120] FIG. 5 shows a perspective bottom view of a handling apparatus according to the invention;

[0121] FIG. 6 schematically shows a perspective top view of a profiling unit forming part of the apparatus according to the present invention;

[0122] FIG. 7 schematically shows a cross-sectional view of the profiling unit with a green tyre fitted around a profiling member in contracted condition;

[0123] FIG. 8 schematically shows a cross-sectional view of the profiling unit with a green tyre fitted around a profiling member in semi-expanded condition;

[0124] FIG. 9 shows the detail in FIG. 7 during the introduction of a gripping device of the green tyre;

[0125] FIG. 10 shows the detail in FIG. 9 during the engagement of the green tyre with the gripping device;

[0126] FIG. 11 shows the green tyre engaged with the gripping device and removed from the profiling unit;

[0127] FIG. 12 schematically shows a radial section view of a finished tyre for bicycle.

[0128] An apparatus for handling green tyres for bicycle according to the present invention is globally denoted with reference numeral 1. The present invention is designed for processing tyres 2 for bicycle, of the type schematically exemplified in FIG. 12, for example for use on road, track, mountain bikes, e-bikes, etc.

[0129] A radially inner surface 2a, substantially facing towards a geometric axis of rotation X of tyre 2, and a radially outer surface 2b substantially facing away from the geometric axis of rotation X, can be identified in tyre 2.

[0130] Tyre 1 for bicycle has a carcass structure 3 comprising at least one carcass ply 4 having mutually parallel cords embedded in an elastomeric matrix.

[0131] Axially opposite end flaps 4a of the carcass ply or plies 4 are engaged to respective bead cores 5, that is, annular anchoring structures integrated in the regions usually identified by the name of beads at which the mechanical engagement between tyre 2 in use conditions and a respective mounting rim takes place.

[0132] A tread band 6, made of elastomeric material, is applied in a radially outer position with respect to the carcass structure 3. Preferably, at least two layers of cords having a cross pattern, respectively, can be identified in the carcass structure 3. The cords belonging to each layer have an inclined development according to a predetermined angle, approximately between about 35 and about 65 with respect to a circumferential development direction of tyre 2. For example, the presence of two carcass plies 4 may be provided, radially superimposed on top of each other, each with the respective cords extending along an inclined direction with respect to the circumferential development of tyre 2 and according to an inclined orientation with respect to the cords belonging to the other carcass ply 4. Alternatively, as shown in FIG. 12, a single carcass ply 4 may be provided, the end flaps 4a whereof, turned up around bead cores 5, extend at least up to an axial centreline plane M of tyre 2, so as to define each a further radially outer layer of cords having crossed orientation with respect to the cords present in the radially inner layer.

[0133] Unlike the tyres typically designed to be used on motor vehicles, tyre 2 for bicycle is generally devoid of a belt structure, that is, of reinforcement belt layers radially interposed between the carcass structure 3 and the tread band 6. In tyres for motor vehicles, these belt layers contribute to increasing the structural strength of tyre 2 and to stabilising the geometry thereof, especially in the crown region, i.e. in the radially outer regions closer to the tread band 6.

[0134] In tyre 2 for bicycle, however, at least one circumferential protective layer 7 may be provided, interposed between the tread band 6 and the carcass structure 3. Where present, said at least one circumferential protective layer 7, the task whereof is essentially to protect tyre 2 from puncture, may have a textile structure or be made in the form of continuous layered tape of synthetic material, and preferably has a thickness not larger than about 0.5 mm, preferably not smaller than about 0.2 mm. Unlike a real belt structure, the circumferential protective layer or layers optionally present in tyre 2 for bicycle do not significantly influence the structural strength, geometric stability and/or dynamic behaviour of tyre 2 itself.

[0135] Preferably, on the radially outer surface 2b of tyre 2 for bicycle, portions of carcass ply 4 directly exposed towards the external environment can be identified between the axially outer edges of the tread band 6 and the bead cores 5. Tyre 2 for bicycle is in fact typically not provided with sidewalls, i.e. layers of elastomeric material applied laterally outside the carcass structure 3, each extending between one of the beads and the respective axially outer edge of the tread band.

[0136] In tyre 2 for bicycle, thickness S of the bead core 5 corresponds to a half of the difference between an outer circumferential diameter De and the seating diameter Dc of bead core 5 itself. As schematized in FIGS. 1 to 4, the building of tyre 2 for bicycle in fact provides that, using suitable application devices (not shown) forming part of a building unit, the carcass ply or plies 4 are deposited according to a cylindrical configuration, such as by wrapping around an outer surface of a building drum 9.

[0137] By means of bead core application devices (not shown), a pair of bead cores 5, for example made of composite material based on natural or synthetic fibres and/or metallic material, is applied at a fixed mutual axial distance D, each around one of the axially opposite end flaps 4a of the carcass ply 4.

[0138] In particular, in the example shown, it is provided that each bead core 5, previously made in the form of finished component, is first fitted around the carcass ply or plies 4 in an axial position corresponding to a circumferential recess 10 formed on the building drum 9 A slight radial expansion of the building drum 9, for example by lever mechanisms forming part of said bead core application devices, causes the application of the bead cores 5 against the carcass ply or plies 4, each at the respective circumferential recess 10.

[0139] Alternatively, the bead core application devices may be configured to make each bead core 5 directly on the building drum 9, wrapping one or more continuous cords around the carcass ply or plies 4 according to a plurality of coils axially juxtaposed and/or radially superimposed on each other.

[0140] Turning up devices (not shown) operating at the building drum 9 then turn up the end flaps 4a of the carcass plies 4 around the respective bead cores 5. During the turning up, the end flaps 4a may be at least partially superimposed on each other and optionally joined in mutual direct contact.

[0141] Tread band application devices (not shown) aid the application of a tread band 6 around the carcass ply 4, in an axially centred position with respect to the bead cores 5. The tread band 6 may be applied in radial superimposition with respect to the turned up end flaps 4a. Once the application has been completed, the turned up end flaps 4a may therefore be partly arranged in an axially inner position with respect to axially opposite edges of the tread band.

[0142] On occurrence, the application of the tread band 6 may be preceded by the application of said at least one circumferential protective layer 7.

[0143] During the application of the tread band 6, an axially central portion of said at least one carcass ply 4, extending axially through an axial centreline plane M equidistant from the bead cores 5, lies against the building drum 9 (FIG. 4).

[0144] The tread band 6 is preferably applied maintaining the mutual axial distance D of the bead cores 5 virtually unchanged. More in particular, the mutual axial distance D between the bead cores preferably remains unchanged during the entire building process, including the application of the tread band 6.

[0145] Once the building has been completed, the green tyre 2 is removed from the building drum 9 to be subjected to other process steps, for example to be transferred to a vulcanisation press.

[0146] To this end, the building drum 9 is radially contracted so as to facilitate the axial removal of the built tyre 2. Being devoid of belt structure and having generally bead cores 5 made from natural or synthetic fibres (carbon, aramid, etc.), tyre 2 for bicycle tends to deform spontaneously or very easily, for example under the effect of its own weight, as soon as it is removed from the building drum 9. In other words, upon removal from the building drum 9, tyre 2 loses its shape with circular development, taking a deformed development in a random and uncontrolled manner.

[0147] Moreover, any residual elastic tensions resulting for example from the radial expansion imposed during the application of the bead cores 5 induce the carcass ply or plies 4 to resume their original diameter, especially at the axially central portion. As a result, tyre 2 initially built according to a cylindrical shape, tends to take a cross-sectional profile substantially convex towards a radially inner direction.

[0148] The present invention aims to allow a reliable handling of the built tyre 2 for bicycle, for the transfer thereof to a vulcanisation press or other working station subsequent to said building unit.

[0149] To this end, a profiling unit 11 is provided, comprising a centring mandrel 12 having a central geometric axis Y, preferably oriented transversely to a horizontal plane, for example according to a direction perpendicular thereto (vertical).

[0150] The centring mandrel 12 comprises a support structure 13 supporting a central upright 14 to which a support plate 15 is fixed, preferably circular in shape, having a peripheral edge extending concentrically on the central geometric axis Y.

[0151] A coupling shank 16 tubular in shape, having a truncated-cone upper end, is preferably fixed on an upper surface of the support plate 15, concentrically to the central geometric axis Y. The centring mandrel 12 is operatively coupled to a radially expandable profiling member 17, extending circumferentially around the central geometric axis Y and preferably arranged peripherally on the upper surface of the support plate 15. Preferably, the profiling member 17 comprises an expandable membrane 18 extending around the central geometric axis Y. The expandable membrane 18 is preferably fixed around a support collar 19 fixed to the support plate 15 concentrically to the central geometric axis Y. The expandable membrane 18 is adapted to be inflated through the controlled introduction of air or other operating fluid under pressure through one or more passages formed, for example, through the support collar 19, to radially expand away from the central geometric axis Y.

[0152] In a possible alternative embodiment not shown, the profiling member 17 may optionally comprise, in addition to or in replacement of the expandable membrane 18 and the support collar 19, a plurality of sectors radially movable with respect to said central geometric axis Y.

[0153] The profiling unit 11 is adapted to operatively engage the built green tyre 2, which can be fitted around the profiling member 17, for example by manual intervention of an operator.

[0154] The profiling unit 11 is further preferably provided with axial positioning devices 20 of the green tyre 2 along the central geometric axis Y of the centring mandrel 12.

[0155] Such axial positioning devices 20 may for example comprise a circumferential support 21 having at least one circumferential supporting surface 21a concentric to the central geometric axis Y and protruding in a radially outer direction with respect to said profiling member 17, for supporting tyre 2 in supporting relation at an axially outer edge thereof, for example defined by one of the beads arranged inferiorly.

[0156] The circumferential support 21 and the centring mandrel 12 are mutually positionable along a direction parallel to the central geometric axis Y, so as to facilitate the adaptation of the profiling unit 11 to the processing of tyres 2 having respectively different widths.

[0157] To this end, it may for example be provided that the circumferential supporting surface 21a of the circumferential support 21 is defined by a plurality of elastically movable sheets 22 peripherally borne by a support ring 23 so as to be circumferentially distributed around the central geometric axis Y. Each sheet 22 may for example comprise an attachment portion 22a fixed to the support ring 23 and extending away from the latter parallel to the central geometric axis Y, and a supporting portion 22b extending transversely from one end of the attachment portion 22a, in a spaced apart position with respect to the support ring 23.

[0158] Preferably, the support ring 23 engages the centring mandrel 12 slidably along a direction parallel to the central geometric axis Y. To this end, the circumferential support 21 may be provided with one or more runners 24, for example borne by a radial structure 25 integral with the support ring 23. Runners 24 are operatively engaged along respective guide rods 26 protruding inferiorly from the support plate 15 of the centring mandrel 12. An interchangeable calibrated insert 27, removably engaged between the radial structure 25 and an abutment 28 inferiorly borne by the support plate 15, stops the descent of the centring mandrel 12 at a predetermined height with respect to the circumferential support 21. The availability of a plurality of calibrated inserts 27 may be provided, having different dimensions and selectively usable as a function of the axial dimension of the green tyre 2 being processed.

[0159] The presence of the correct calibrated insert 27, pre-selected as a function of the axial dimension of the tyres being processed, makes the green tyre 2 fitted around the centring mandrel 12, coming into contact with the circumferential supporting surface 21a, arrange itself with respect to the profiling member 17 in a predetermined axial position along the central geometric axis Y. More precisely, the green tyre 2 is stopped and supported in a position such that the axial centreline plane M thereof coincides with an axial centreline plane M of the expandable membrane 18, or other type of profiling member 17.

[0160] Preferably, sheets 22 are spaced apart from the central geometric axis Y by a greater extent than a maximum radius of the profiling member 17 with respect to the central geometric axis Y itself, at least in the radially contracted condition. It is therefore possible to prevent mechanical interference between sheets 22 and the profiling member 17, during a mutual axial handling thereof. The profiling member 17 is adapted to be activated, for example by introducing operating fluid in the expandable membrane 18, when the green tyre 2, previously fitted around the profiling member 17, is supported by the circumferential supporting surface 21a.

[0161] To this end, it may be provided that the activation control of the profiling member 17 takes place by an electronic control unit (not shown), upon receipt of an enabling signal emitted by sensor members 29 designed to detect the presence of tyre 2 around the profiling member 17 itself. Such sensor members 29 may for example comprise an optical detector oriented towards the profiling member 17. The optical detector is configured to emit a presence signal when tyre 2 is interposed between the profiling member 17 and the optical detector itself.

[0162] The expandable membrane 18 or other profiling member 17 is consequently expanded from a radially contracted condition (FIG. 7) to a radially expanded condition (FIG. 10). Preferably, in the contracted condition, the profiling member 17 has a maximum diameter smaller than the seating diameter Dc, so as to have at least one portion distant from the radially inner surface 2a of the built tyre 2. In the expanded condition, the profiling member preferably has, at least in the vicinity of the axial centreline plane M, a maximum diameter greater than the seating diameter, so as to operate against the radially inner surface 2a of tyre 2, exerting a thrust action in a substantially radial direction from the inside towards the outside of tyre 2 itself. On the effect of such a thrust action, the green tyre 2 is therefore subjected to a restoration of the development so as to take again a circular configuration around the geometric axis of rotation X. At the same time, tyre 2 is centred with the geometric axis of rotation X thereof coincident with the central geometric axis Y of the centring mandrel 17 and of the profiling member 17.

[0163] The expansion of the expandable membrane 18, moreover, tends to translate the tread band 6 towards a radially outer direction with respect to the bead cores 5, so as to impart a cross-sectional convex profile to the green tyre 2 towards a radially outer direction.

[0164] In order to facilitate the profiling of tyre 2 in the manner described above, the initial contact between the expandable membrane 18 and the built tyre 2 preferably takes place in the vicinity of the axial centreline plane M of tyre 2 itself.

[0165] Since the green tyre 2 positioned around the profiling member 17 may have a significantly deformed configuration, it is preferable that the profiling of tyre 2 itself is not carried out by a single expansion action, but by two or more expansion actions cyclically repeated and alternating with respective contraction actions. It may further be provided that such cyclically repeated expansion actions follow one another respectively with progressively increasing intensity.

[0166] More in particular, a first expansion action may be carried out by imposing a relatively small expansion to the profiling member 17 with respect to that imposed during a subsequent expansion action. In the example shown, to this end it may be provided that the first expansion action is carried out by feeding operating fluid in the expandable membrane 18 at a first pressure value, suitable for determining a sufficient circumferential stretching of tyre 2. In particular, the tyre may thus be stretched according to a circular configuration coaxially to the central geometric axis Y. For example, the first expansion action may be carried out by feeding the operating fluid at a pressure of between about 10 KPa and about 150 KPa, for a time indicatively of between about 1 s and about 25 s. As a result of the first expansion action, the profiling member 17 is preferably brought to a semi-expanded condition, intermediate between the contracted condition and the expanded condition (FIG. 8).

[0167] The operating fluid is then discharged from the expandable membrane 18 to determine a first contraction, so as to obtain the detachment, preferably complete, from the inner surface of tyre 2.

[0168] Immediately after the contraction, indicatively within a time not exceeding about 30 s, operating fluid is again introduced in the expandable membrane 18 at a higher pressure than the first value, so as to determine a second expansion action and subsequent profiling of tyre 2. For example, the second expansion action may be carried out by feeding the operating fluid at a pressure of between about 10 KPa and about 150 KPa, for a time indicatively of between about 1 s and about 25 s. As a result of the second expansion action, the profiling member 17 can be brought to the expanded condition.

[0169] Since the green tyre 2 is already pre-profiled due to the first expansion action, the action of the expandable membrane 18 during the second expansion action may be more uniform, so as to facilitate the profiling of tyre 2 without causing distortions due to localised stresses.

[0170] On occurrence, more than two expansion action interspersed with respective contraction actions may be provided.

[0171] After or concurrently with the execution of the profiling action, the green tyre 2 is adapted to be engaged by a gripping device 30 borne by a transfer member 31, which removes it from the profiling unit 11 to bring it to a subsequent working station, such as a vulcanisation press.

[0172] Preferably, the transfer member 31, for example comprising a robotic arm, preferably of the anthropomorphic type with at least six axes, or other handling unit, is configured to engage the green tyre 2 by the gripping device 30, while tyre 2 itself is mechanically retained so as to maintain said cross-sectional convex profile in a radially outer direction.

[0173] The gripping device 30 preferably comprises gripping elements 32 circumferentially distributed around a gripping axis Z and defining each a gripping point of tyre 2.

[0174] On the action of at least one driving actuator (not shown in the drawings), the gripping elements 32 are radially movable with respect to the gripping axis Z, between a rest condition, in which they are radially distanced with respect to the central geometric axis Y (FIG. 9), and a working condition in which they are radially approached with respect to the central geometric axis itself (FIGS. 10 and 11).

[0175] It may be provided that a single driving actuator operates simultaneously on multiple gripping elements 32, preferably all, through a handling mechanism 33 configured to radially move them in a simultaneous and synchronized manner. To this end, it may be provided that the activation control of the gripping elements 32 takes place by an electronic or pneumatic control unit (not shown).

[0176] Each gripping element 32 may for example comprise a support 34, such as plate-shaped, extending parallel to the gripping axis Z and having an upper end constrained to the handling mechanism 33 and a lower end bearing a suction member 35 to which a suction conduit is connected. The suction member 35 can be activated by the effect of a pneumatic suction produced through a suction conduit.

[0177] The transfer member 31 coaxially places the gripping device 30 above the profiling unit 11 with the gripping elements 32 arranged in the rest condition.

[0178] A descent translation of the gripping device 30 is then determined along the gripping axis Z, to obtain the mutual engagement between the coupling shank 16 and a tailstock 36 counter-shaped thereto, coaxially borne by the gripping device 30. The engagement of tailstock 36 with the coupling shank 16 defines a shape coupling configured to determine a precise alignment of the gripping device 30 with the gripping axis Z thereof coaxially aligned with respect to the central geometric axis Y of the profiling member 17 and thus, with respect to the geometric axis of rotation X of the green tyre 2. The engagement of tailstock 36 with the coupling shank 16 also causes the stop of the gripping device 30 in a predetermined axial gripping position with respect to the profiling member 17. As exemplified in FIG. 9, in the axial gripping position, the gripping points defined each concentrically by the respective suction member 35 are arranged in a relation of substantial coplanarity with the axial centreline plane M of the profiling member 17 and of the green tyre 2 fitted around it.

[0179] Preferably, the lowering towards the axial gripping position is carried out by maintaining the gripping elements 32 in the rest condition, thus reducing the risk of sliding and/or interference against the green tyre 2. Upon reaching the axial gripping position, the above driving actuator can be activated, which causes the translation of the gripping elements 32 towards the operating condition, approaching the tread band 6 of tyre 2.

[0180] Moreover, it is further preferably provided that the lowering of the gripping device 30 towards the axial gripping position is carried out after the beginning of the profiling operation of tyre 2, but before such a profiling operation has been completed. More in particular, such a lowering takes place for example when the profiling member 17 has been returned to the contracted condition after carrying out at least one expansion action.

[0181] Upon reaching the operating condition, the gripping elements 32 may be still slightly distanced with respect to tyre 2. In this case, a last expansion action imposed by the profiling member 17 brings the tread band 6 against the suction members 35 of the gripping elements 32.

[0182] Alternatively, it may be provided that the radial contraction of the gripping elements 32 takes place when the profiling member 17 has already reached the expanded condition following the last expansion action. In this case, upon reaching the operating condition, the gripping elements 32 come into contact with tyre 2, bringing the respective suction members 35 against the outer surface of the tread band 6 while the profiling member 17 is in the expanded condition.

[0183] In both cases, the pneumatic suction effect produced by the suction members 35 makes the gripping elements 32 be operatively activated against a radially outer surface of the tread band 6, exerting attraction actions directed in radial distancing of the geometric axis of rotation X of tyre 2, and distributed along the whole circumferential development of the latter.

[0184] The engagement of tyre 2 to the transfer member 31 can thus be obtained while tyre 2 itself is still mechanically retained by the profiling member 17, which imposes at least partially retaining said cross-sectional convex profile in a radially outer direction. Once the engagement has taken place, the profiling member 17 can be returned to the radially contracted condition, so that tyre 2 can be axially removed from the profiling unit 11 by the effect of the lifting of the gripping device 30. The attraction actions exerted on the tread band 6 by the gripping elements 32 mechanically retain tyre 2, thus ensuring the maintenance of the latter in a condition very close to the profiled one even after the disengagement thereof from the profiling member 17. Tyre 2 is therefore adapted to retain a stable geometrical shape for the correct transfer to the next working station. In particular, retaining the profiling condition favours the correct engagement of tyre 2 with the members designed to the treatment thereof in the vulcanisation press or other subsequent working station.