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US 4,288,265 AGranted
Process and apparatus for manufacturing radial tires
AssigneeIndustrie Pirelli S.p.A.
InventorsAntonio Pacciarini, Giorgio Bertoldo
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AssigneeIndustrie Pirelli S.p.A.
InventorsAntonio Pacciarini, Giorgio Bertoldo
Estimating the term…
A process is provided for manufacturing radial tires for a motor vehicle having a radial carcass, a reinforcing structure with at least two layers of criss-crossed symmetrically arranged metallic cords forming a belt, and a tread. The process involves a series of steps which comprise: building up a carcass in a cylindrical configuration on a first expandable building drum and shaping the carcass into a toroidal configuration. A reinforcing belt is also formed by winding two layers of metallic cords on an auxiliary expandable drum with a diameter equal to the external diameter of the toroidal shaped carcass. The belt is maintained in slidable contact on the drum and shaped toroidally by expanding the auxiliary drum. The belt is then removed from the auxiliary drum and transferred with a tread band to the carcass on the first drum. The carcass is toroidal shaped again to assemble the carcass and belt. The assembly is vulcanized under pressure in a mold.
In a process for manufacturing radial tires for a motor vehicle having a radial carcass, a reinforcing structure with at least two layers of metallic cords forming a belt, the cords of adjacent layers being criss-crossed with respect to each other, and symmetrically oriented with respect to the longitudinal direction of the tire, and a tread, the said process comprising the steps of:
A drum for separately shaping a reinforcing belt and a tread band for assembly with a radial carcass in the manufacture of a tire for a motor vehicle, said drum comprising means for expansion thereof and for transforming said belt from a cylindrical configuration into a toroidal configuration, said means having a surface over which said belt will slide when transformed from a cylindrical configuration into a toroidal configuration, said means comprising a plurality of comb shaped support members disposed circumferentially and parallel to the drum axis with void spaces interposed therebetween, a plurality of convex sectors with a total convex surface disposed below the upper surface of said support members in the cylindrical configuration of the said drum, and means for passing the sectors between the said void spaces and for expanding the sectors to a position above the said support members for imparting a toroidal configuration to the auxiliary drum.
A plant for manufacturing radial tires, comprising a radial carcass, a reinforcing structure comprised by at least two layers of metallic cords criss-crossed one with the other for forming the belt and the tread, said plant being characterized by the fact of comprising a main expandable tire building drum for shaping the carcass from a cylindrical configuration to a first toroidal shape, and then to a subsequent toroidal shape having a higher value than the first shape, said auxiliary expandable drum having the structure of claim 25 and being adapted for changing a configuration from cylindrical to toroidal, for changing the said layers of metallic cords from a cylindrical configuration to a toroidal one corresponding to the configuration of the second shaping of the carcass, means for transferring the annular layered-band that is comprised by the reinforcing structure and by the tread, from said auxiliary drum onto said main drum after the first toroidal shaping of the carcass and prior to the second toroidal shaping of the same carcass.
In a process for manufacturing tires for a motor vehicle having a carcass, a reinforcing structure with metallic cords forming a belt, and a tread, the improvement which comprises
Dependencies are inferred from the claim text.