GB808548A - Improvements relating to pneumatic vehicle wheel tyres having a breaker structure - Google Patents

Abstract

808,548. Pneumatic tyres. PIRELLI S.p.A. Feb. 26, 1957 [March 8, 1956], No. 6466/57. Class 144 (2).. In a pneumatic tyre having a substantially circumferentially inextensible breaker structure which is placed under circumferential tension on inflation of the tyre, the breaker structure comprises a strip or a set of superimposed strips, of parallel-cord rubberized fabric, bias cut to provide a cord angle of between 5 and 30 degrees, which is folded upon itself along two circumferential lines spaced apart a distance defining the width of the breaker, the unfolded strip, or set of strips, having a width at least double the width of the formed breaker. The folded strip or set provides a plurality of superposed layers throughout the width of the breaker, at least two of the layers having their respective cords in crossed relation to each other, preferably symmetrically with respect to the circumferential direction. Fig. 2 shows a strip with two lateral portions, each of a width five sixths of that L of the central portion which defines the overall width of the breaker, so that in their folded positions shown the two lateral portions overlap each other for a width S which is two thirds the width L. Two such folded strips may be superposed to form a breaker, the overall folded width of each strip being either the same or different. Fig. 4 shows a breaker formed by folding two superimposed strips and Fig. 5 shows two independent superposed cross-laid strips of parallel-cord fabric disposed between two of the layers of a folded strip. The independent strips may alternatively be disposed adjacent one or both outer faces of the folded strip. In all cases the cords of the strips may comprise metallic or natural or synthetic textile material rubberized with natural or synthetic rubber or rubbery plastic material.