Process for the manufacture of radial tires
AssigneeSocieta' Pneumatici Pirelli S.p.A.
InventorRenato Caretta
Life of this patent
Estimating the term…
Abstract
A process for manufacturing radial type motor vehicle pneumatic tires is provided in which an annular reinforcing structure is disposed on a toric carcass. The reinforcing structure is built up of two layers of metallic cords crossed with each other, and an additional third layer of heat shrinkable textile cords that form, with the longitudinal direction of the tire, an angle which is not zero and is a smaller angle than that of the underlying cords. The third textile layer is applied by butt-joining its respective opposite ends along a straight line parallel to the metallic cords of the underlying metallic layer.
Claims8
A process for making radial tires comprising a radial carcass, a tread, an annular reinforcing structure inserted between the carcass and the tread, the said annular reinforcing structure comprising at least two layers of metallic cords, and in a radially outermost position, a third layer of textile cords that shrink in length under the effects of heat, said metallic cords, of each layer being disposed parallel to each other and crossed with the cords of the adjacent layer, and forming an angle with the longitudinal direction of the tire, said textile cords being disposed parallel to each other and forming with the longitudinal direction of the tire an angle which is not zero but is smaller than the angle formed by the metallic cords of the second metallic layer, said process comprising the steps of:
- (a) constructing the radial carcass on a tire building drum;
- (b) shaping the carcass in its unvulcanized state into a toric configuration;
- (c) placing the reinforcing annular structure and the tread band on the toric shaped carcass;
- and
- (d) molding and vulcanizing the tire, said method being characterized by the fact of joining the opposite ends of the third layer of the annular reinforcing structure along a line which extends in the direction of and at substantially the same angle as of the metallic cords of the second metallic layer.
In a process for making a pneumatic tire comprising forming a cylindrical radial carcass, transforming the cylindrical radial carcass into a first toroidal shape, assembling with the resulting first toroidal shaped carcass an annular reinforcing member, transforming the resulting assembly into a second toroidal shaped carcass and annular reinforcing member, assembling with said second toroidal assembly an elastomeric band from which a tread will be formed, and molding and vulcanizing the resulting toroidal shaped assembly under pressure to form a tire, the improvement which comprises the steps of assembling with said first toroidal shaped radial carcass an annular reinforcing member comprising first and second layers of metallic cords parallel to each other in each layer, the metallic cords of the first layer being disposed on a bias with respect to the longitudinal direction of the tire, the cords in the second layer being biased in a direction opposite from those of the first layer, and a third layer of heat shrinkable textile cords disposed radially outwardly of the said first and second layers, the said heat shrinkable cords being parallel to each other and biased in a direction corresponding to the bias of the cords of said first layer, said third layer being a band wound around the carcass and underlying layers with its ends abutting along a line, across the width of the layer, which is disposed in a plane substantially parallel to the plane of the cords of the said second layer, and along a direction parallel to the direction of the metallic cords of said second layer.
A pneumatic tire for a motor vehicle wheel comprising a radial carcass, a tread and an annular reinforcing member disposed between the tread and carcass having first and second layers of metallic cords, the cords of the first layer being disposed at an angle with respect to the longitudinal direction of the tire and the cords of the second layer being disposed at an angle with the longitudinal direction of the tire in a direction opposite to the direction of the cords of the first layer, and a third radial outer layer of cords consisting essentially of heat shrinkable textile cords parallel to each other and disposed at an angle which is not zero but is smaller than the angle of inclination of the cords in the immediately adjacent layer of cords, whereby the cords in the second layer cross the cords of the first and third layers, said third layer being a band of cords wound around the carcass with its ends abutting in a line which is disposed across the width of the third layer in the same direction and at substantially the same angle as the cords are disposed in the said second layer.
Dependencies are inferred from the claim text.