Patent ID: 6460589
Filing Date: 2002-10-08
Classification: B60C,Y10T

Abstract:
A tire, comprising at least one radial carcass reinforcement which is formed of at least one ply of inextensible reinforcement elements and is anchored within each bead B to a bead wire to form an upturn, said carcass reinforcement being assembled as a raw blank on a building drum prior to shaping into a torus, the non-upturned part of the carcass reinforcement, in the region of the bead located on either side of the point of inflection where the trace of its meridian profile changes curvature to become rectilinear or concave, being reinforced, at least axially to the inside, by an additional reinforcement armature of at least one ply formed of metal reinforcement elements, the radially lower end of which is radially below a straight line Dâ€² which is parallel to the axis of rotation and passes through that point of the coating layer of the anchoring bead wire which is radially farthest from the axis of rotation, but above a straight line D which is parallel to the axis of rotation and passes through that point of the coating layer of the anchoring bead wire which is radially closest to the axis of rotation, and the radially upper end of which is located at a radial distance from the straight line D which is between a quantity equal to half the radial distance between the straight lines D and Dâ€³ increased by half the radial distance between the straight lines D and Dâ€² and a quantity equal to half the radial distance between the straight lines D and Dâ€² reduced by half the radial distance between the straight lines D and Dâ€², the straight line Dâ€³ being the straight line at the point of greatest axial width, the tire being characterized in that the reinforcement elements of the additional reinforcement armature are lengths or assemblies of lengths of circumferential cables, of a circumferential length of between 0.2 and 0.4 times the average circumferential length of the additional reinforcement armature, as measured upon the laying of said at least one ply of said additional reinforcement armature on the building drum for the carcass reinforcement blank.