The tire bead core of a pneumatic tire is substantially inextensible and ensures that the tire is retained on a wheel rim. Typically a tire bead core is produced by winding bead wire, e.g. steel wire, in several layers around a former. When the filamentary material comprises several strands which have previously been brought together and passed through a rubber-coating device to form a "tape" of filamentary material, such "tapes" of filamentary material are wound helically a number of convolutions on to a former to form an annular bead wire core of a desired strength. Prior to wrapping tire ply material around the bead wire core, a ring of elastomeric filler material is wrapped around the annular bead wire core to produce a tire bead core assembly.
The manufacture of the annular bead wire core and the fitting of the ring of filler material onto the bead wire core are presently carried out as separate operations resulting in considerable time being taken and extra labour being required.
The present invention aims to provide apparatus and a method for the manufacture of an assembly of an annular bead wire core and ring of filler material as a semi-finished component for use in the tire industry. It is also an aim of the present invention to ensure that, in the semi-finished component, the wound bead wire, i.e. the wound rubber-coated strand or strands which form the tire bead core, are correctly positioned from the inner to the outer convolutions since, if the strands are placed incorrectly, there is a risk that the semi-finished component could not be further processed on tire making machines and that air would become trapped within the tire bead core assembly with disastrous consequences in the characteristics of the finished shaped tire. A further aim of the invention is to ensure that the ring of filler material is virtually seamless lying in one whole piece circumferentially against the wound rubber-clad strands around the circumference.
USPTO Backgrounds
USPTO Backgrounds