PROCESS AND PLANT FOR BUILDING TYRES

• US 20190210313A1
• Filed: 11/30/2016
• Published: 07/11/2019
• Est. Priority Date: 12/28/2015
• Status: Active Grant

• Current Assignee: Pirelli Tyre SPA (Pirelli & C SPA)
• Original Assignee: Pirelli Tyre SPA (Pirelli & C SPA)
• Inventors: LO PRESTI, Gaetano, MANCINI, Gianni, MARCHINI, Maurizio, PORTINARI, Gianni
• Granted Patent: US 11,298,900 B2
• Time in Patent Office: Days
• CPC Class Codes: B29D 30/20 by the flat-tyre method, i.e. building on cylindrical drums
• CPC Class Codes: B29D 30/36 Expansion of tyres in a flat form , i.e. expansion to a toroidal shape independently of their building-up process, e.g. of tyres built by the flat-tyres method or by jointly covering two bead-rings

Abstract

A carcass sleeve including a carcass ply and a pair of annular anchoring structures is fitted around a toroidal forming drum arranged in a first radially contracted operational condition. The carcass sleeve is toroidally shaped against a radially inner surface of an annular contrast element. The forming drum is positioned inside the carcass sleeve and is concurrently expanded towards a second operational condition. Upon reaching the second operational condition, the toroidally shaped carcass sleeve is coupled to the forming drum. The forming drum, coupled to the carcass sleeve, is adapted to be transferred in proximity of an application device of additional components externally to the carcass sleeve.

Claims

1-44. -44. (canceled)

45. A process for building tyres, including:

arranging a carcass sleeve including at least one carcass ply and a pair of annular anchoring structures;

arranging a toroidal forming drum in a first radially contracted operational condition;

arranging said carcass sleeve in a position radially external to said forming drum;

toroidally shaping said at least one carcass sleeve against at least one radially inner surface of an annular contrast element, while said forming drum is positioned inside the carcass sleeve;

expanding said forming drum up to a second radially expanded operational condition;

coupling the toroidally shaped carcass sleeve to the forming drum in said second operational condition; and

arranging said forming drum, coupled to said carcass sleeve in proximity of at least one application device of additional components externally to said carcass sleeve.

46. The process according to claim 45, further including arranging said annular contrast element in a radially outer position around said carcass sleeve, before the toroidally shaping the carcass sleeve.

47. The process according to claim 45, wherein said annular contrast element is arranged around the carcass sleeve after the forming drum has been coaxially inserted into the carcass sleeve.

48. The process according to claim 45, wherein at least part of an expansion of the forming drum is carried out concurrently with at least part of the toroidally shaping of the carcass sleeve.

49. The process according to claim 45, wherein in said second operational condition, a radially outer surface of the forming drum acts in contact relation against a radially inner surface of the shaped carcass sleeve against the annular contrast element.

50. The process according to claim 45, wherein the outer surface of the forming drum remains spaced from the carcass sleeve during expansion of the forming drum, at least before reaching the second radially expanded operational condition.

51. The process according to claim 45, wherein an outer surface of the forming drum reaches a contact relation against a radially inner surface of the carcass sleeve upon reaching said second operational condition.

52. The process according to claim 45, wherein upon the toroidally shaping, an inner surface of the carcass sleeve reaches a maximum sleeve diameter greater than a maximum drum diameter reached by the outer surface of the forming drum in the second operational condition.

53. The process according to claim 45, wherein upon reaching said second operational condition, a radially outer surface of the forming drum has, at least in an equatorial plane of the drum, a distance not greater than 2 mm from a radially inner surface of the shaped carcass sleeve against the annular contrast element.

54. The process according to claim 45, wherein upon reaching said second operational condition, a minimum distance between a radially outer surface of the forming drum and a radially inner surface of the shaped carcass sleeve against the annular contrast element is detectable at an equatorial plane of the forming drum.

55. The process according to claim 45, further including a radial expansion of the annular contrast element carried out concurrently with the toroidally shaping the carcass sleeve.

56. The process according to claim 45, wherein the radial expansion of the annular contrast element occurs through elastic deformation of the annular contrast element.

57. The process according to claim 45, wherein the radial expansion of the annular contrast element occurs by effect of a radial thrust exerted by the forming drum upon reaching the second operational condition.

58. The process according to claim 45, wherein the annular contrast element includes at least one transfer ring.

59. The process according to claim 58, wherein said transfer ring is movable along a first translation axis and a second translation axis perpendicular thereto.

60. The process according to claim 58, wherein said transfer ring carries internally a plurality of pads circumferentially distributed and radially movable between a release condition and a gripping condition in which the pads are radially contracted.

61. The process according to claim 45, wherein the annular contrast element includes at least one belt layer.

62. The process according to claim 45, wherein the annular contrast element includes at least one belt layer engaged inside a transfer ring.

63. The process according to claim 45, further including arranging said annular contrast element by:

forming at least one belt layer around an auxiliary drum;

engaging a transfer ring around said at least one belt layer; and

translating said transfer ring for removing said at least one belt layer from the auxiliary drum and positioning said annular contrast element around the carcass sleeve.

64. The process according to claim 63, wherein the forming said belt layer includes wrapping a band-like semi-finished product circumferentially around said auxiliary drum and butt-jointing opposite ends of said band-like semi-finished product.

65. The process according to claim 45, wherein said application device of additional components is installed in a green tyre completion line remote with respect to said shaping station.

66. The process according to claim 45, wherein said additional components include at least one belt layer applied in a radially outer position on the carcass sleeve.

67. The process according to claim 66, wherein the belt layer is made by sequential application of a plurality of strip-like elements consecutively adjacently arranged around a circumferential development of the carcass sleeve.

68. The process according to claim 45, wherein said additional components include at least one tread band applied in a radially outer position to the carcass sleeve.

69. The process according to claim 68, wherein the tread band is made by winding with at least one continuous elongated element of elastomeric material according to circumferential covering turns consecutively arranged adjacent around a radially outer surface of said carcass sleeve.

70. The process according to claim 45, wherein said additional components include at least one sidewall applied laterally against the carcass sleeve.

71. The process according to claim 70, wherein the sidewall is made by winding with at least one continuous elongated element of elastomeric material according to circumferential covering turns consecutively and adjacently arranged against a lateral surface of said carcass sleeve.

72. The process according to claim 45, wherein the carcass sleeve is made in at least one building station and subsequently transferred to a shaping station.

73. The process according to claim 45, wherein the shaping of the carcass sleeve is carried out by introducing an inflating operating fluid inside the carcass sleeve.

74. The process according to claim 45, wherein the shaping of the carcass sleeve occurs through mutual approach of a pair of flange elements coaxially facing each other and operationally engaging respective annular anchoring structures carried by respective axially opposite ends of the carcass sleeve.

75. The process according to claim 74, wherein the carcass sleeve is coaxially fitted around the forming drum arranged in the shaping station.

76. The process according to claim 75, wherein fitting the carcass sleeve around the forming drum includes:

positioning the flange elements in a loading/unloading condition in which they are mutually spaced by an extent greater than an axial dimension of the unshaped carcass sleeve;

engaging the forming drum coaxially to one of said flange elements;

positioning the carcass sleeve coaxially between the flange elements;

axially translating the carcass sleeve to arrange the carcass sleeve in an axially centred position with respect to the forming drum.

77. The process according to claim 74, wherein arranging said annular contrast element in a radially outer position around the carcass sleeve includes the following actions:

positioning said annular contrast element coaxially between the flange elements;

axially translating the annular contrast element to move the annular contrast element to a stand-by position laterally arranged with respect to said flange elements.

78. The process according to claim 77, wherein the annular contrast element is positioned coaxially to the flange elements laterally with respect to the forming drum, and axially translated away from the forming drum.

79. A plant for building tyres, including:

a shaping station including engagement devices of a carcass sleeve;

shaping devices operating in the shaping station for shaping the carcass sleeve according to a toroidal configuration;

an expandable toroidal forming drum engageable in the shaping station in a radially inner position in the carcass sleeve;

actuator devices operating in the shaping station for radially expanding the forming drum inside the carcass sleeve;

at least one application device of additional components;

transfer devices configured for transferring the forming drum carrying said toroidally shaped carcass sleeve from the shaping station to said at least one application device of additional components,

at least one annular contrast element positionable around the forming drum and the carcass sleeve in the shaping station and carrying at least one radially inner surface operating against the carcass sleeve itself during the action of the actuator devices or of the shaping devices.

80. The plant according to claim 79, wherein the annular contrast element has an inner diameter smaller than an outer diameter that would be taken by the carcass sleeve on the action of the actuator devices in the absence of the annular contrast element.

81. The plant according to claim 79, wherein the annular contrast element has an inner diameter substantially equal to an outer diameter of the forming drum in an expanded condition, added to twice the thickness of a radially outer portion of the shaped carcass sleeve.

82. The plant according to claim 79, wherein the forming drum in a first radially contracted operational condition has a maximum outer diameter smaller than a minimum inner diameter of the carcass sleeve.

83. The plant according to claim 79, wherein the forming drum includes a central shaft and a plurality of sectors circumferentially distributed around the central shaft and movable from a first operational condition, in which said sectors are adjacent the central shaft, to a second operational condition in which said sectors are moved away from the central shaft.

84. The plant according to claim 79, wherein said engagement devices include a pair of flange elements coaxially facing each other and operationally engageable with respective annular anchoring structures carried by respective axially opposite ends of the carcass sleeve.

85. The plant according to claim 79, further including a carriage carrying one of said flange elements and movable towards the other flange element for switching the shaping station between a loading/unloading condition, in which the flange elements are mutually spaced by an extent greater than an axial dimension of the unshaped carcass sleeve and a working condition in which the flange elements are mutually spaced by an extent substantially corresponding to the axial dimension of the carcass sleeve.

86. The plant according to claim 85, wherein in the loading/unloading condition, the flange elements are mutually spaced by an extent at least twice the axial dimension of the unshaped carcass sleeve.

87. The plant according to claim 79, wherein said annular contrast element is radially movable to fit between the flange elements arranged in the loading/unloading condition.

88. The plant according to claim 86, wherein the annular contrast element is movable coaxially to the forming drum, between a working position axially interposed between the flange elements, and a stand-by position laterally arranged with respect to said flange elements.