Radial pneumatic tires having reinforced sidewalls

Claim 1

In a pneumatic tire for vehicle wheels comprising a radial carcass constituted at least by one layer of cords lying on substantially radial planes, a tread and a breaker arranged between the carcass and the tread and comprising at least two superimposed cord layers, said cords being inclined at an angle between 10° and 35° with respect to the equatorial plane of the tire and being parallel to one another in any layer and crossing those of the adjacent layer, said breaker comprising further, in a radially outer position with respect to said layers, at least a strip of cords of textile material which shrinks in length with increase in temperature, said cords being arranged in a position parallel to the equatorial plane of the tire, and in each tire sidewall, a reinforcement of at least one cord layer arranged in an axially outer position to the carcass, the radially innermost edge of said reinforcing layer being disposed substantially adjacent to the bead core of the relative sidewall and axially outer to the turned up portion of the carcass wound about said bead core and a radially outer stretch of said reinforcing layer being disposed in said breaker between said two superimposed cord layers and said cord strip having the cords arranged in a position parallel to the equatorial plane of the tire, each cord of the reinforcing layer being inclined with respect to the circumferential line of the tire at an angle decreasing along the path of the cord from said radially innermost edge toward said stretch and variable in a range whose extreme values, chosen on the ground of the ratio h/c between the height and the maximum width of the tire section (ranging between 0.30 and 0.80), are 55° and 15°, the improvement wherein said cord layer of said reinforcement is folded twice, so as to have a first skirting extending substantially from said radially innermost edge to a first folded edge arranged at the tire shoulder, a second skirting superimposed on the former and extending from said first folded edge to a second folded edge radially innermost to the former, and a third skirting superimposed on the other two and extending from said second folded edge to a position radially outermost to the latter in order to be disposed in said breaker between said two superimposed cord layers and said cord strip having the cords arranged in a position parallel to the equatorial plane of the tire.