摘要 |
A pneumatic tire bead is formed into a spiral coil consisting of a plurality of convolutions or turns of wire. The wire may be round, square, oval or hexagonal in cross section. A crimp or offset bend is made in each of the convolutions a distance of one wire width or a fraction of the wire width in each full 360 degree wire turn such that the ends of the bead wire permit the bead side walls to remain in flat parallel planes. This offset relationship reduces nonuniformity in the tire heretofore produced by spirally wound wire beads. The bead wire can be wound in a vertical plane or in a radial spiral clock-like spring fashion. In another embodiment a pair of mirror image offset coils are joined together to form a composite bead preferably for use in heavy duty applications. In still another embodiment a single flat hoop may be placed between a pair of mirror image offset coils to increase resistance to circumferential distortion.
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