Process for injection molding a tire having a crown and sidewalls of different compositions
AssigneeIndustrie Pirelli S.p.A.
InventorsAchille Gallizia, Giorgio Tangorra
Life of this patent
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Abstract
A process for injection molding a crown of a vehicle tire from one composition and the sidewalls from a different composition involves the steps of shaping the reinforcing structure in the mold, injecting a first composition over one side of the reinforcing structure to form a crown with a tread and injecting a second composition to form the sidewalls with an interface within the proximity of the edges of the reinforcing structure. In a preferred embodiment, the tire has the configuration of the one disclosed in U.S. Pat. No. 3,805,868. The annular reinforcing structure is shaped to be generally convex but concave towards the tread along its edges.
Claims15
A process for the manufacture of tires comprising a crown made of a first compound and including an annular reinforcing structure and sidewalls made of a second compound, including the steps of preparing the reinforcing structure, introducing the same into a mold defining the desired final shape of the complete tire, injecting separately but substantially simultaneously the first compound and the second compound into the mold to fill the free space in said mold so that said first and second compounds flow the one towards the other at least in the delimiting zone between the crown and each sidewall, controlling the relative volumes of the said first and second compounds so injected into the mold to define the delimiting surface between the crown and each sidewall.
A process for making a vehicle tire having beads, sidewalls, crown, and a crown-reinforcing member, which comprises:
- providing two mold cavities having surfaces respectively defining the crown portion and the sidewalls and beads portion of the tire, except at the junction of the crown to the sidewalls, said mold cavities communicating in correspondence to said junction;
- disposing an annular reinforcing member for the crown having laterally spaced edges in the first of said cavities defining the crown portion of the tire;
- injecting a measured volume of a first compound into said first cavity;
- and
- separately and substantially simultaneously injecting a measured volume of a second compound which is different from the first compound, into the second of said cavities, defining the sidewalls and beads portion of the tire;
- the ratio of said two measured volumes determining the surface at which the junction of the crown to the sidewalls is formed.
Dependencies are inferred from the claim text.