Tire building system

Apparatus for building a radial ply tire having a given bead diameter and a given toroidal crown diameter comprising a solitary band building drum having a fixed non-collapsible continuous cylindrical surface;

• means permanently fixed mounting said band building drum for rotation about an axis fixed in space, said band building drum having a plurality of closely spaced orifices distributed in rows and columns along and around said cylindrical surface, and airflow means mounted within said drum connected to flow air under pressure through said orifices between the inner surface of a cylindrical precarcass band on said drum and the outer cylindrical surface of said drum;
• solitary carcass-shaping means providing three diametral conditions including a first condition being of less diameter than said bead diameter and an intermediate condition providing an axially and circumferentially firm and continuous cylindrical support surface having a diameter materially larger than the diameter of said band building drum and having a radially inwardly extending shoulder at each axial end of said support surface, means mounting said carcass-shaping means for coaxial alignment and axially spaced apart relation with respect to said band building drum;
• and band transfer means cooperable with said orifices and said airflow means to release a precarcass band from said drum and operable to carry said precarcass band between said drum and said carcass-shaping means without change in its cylindrical form and size as built on said drum and having three predetermined positions, said band transfer means comprising a pair of coaxial rings, means mounting the respective said rings for movement symmetrically toward and away from each other, each ring having a plurality of radially movable plungers spaced angularly about and extending radially through the respective ring and movable inwardly and outwardly thereof, a piston means mounted on each plunger and responsive to air pressure thereon to urge said plungers radially inwardly relatively of said rings, yieldable cup means secured on the radially inner end of each plunger for engagement with the exterior surface of said precarcass band, adjustable stop means on each said plunger outwardly of the respectively associated ring limiting radially inward travel of said plungers to dispose said cup means in fixed closely spaced radial relation with said drum, said cup means being sufficient in number and in location to support said precarcass band in cylindrical shape and size substantially identical to its cylindrical shape and size when on said band building drum while being moved from the first to the intermediate and from the intermediate to the third of said three positions, said plungers being displaceable radially outwardly in response to expansion of said carcass-shaping means from said first condition to said intermediate condition thereby to expand a central portion of a band placed by the transfer means around the shaping means.