IE36940B1 - Improvements in or relating to pneumatic tyres - Google Patents

Abstract

1417968 Pneumatic tyres DUNLOP Ltd 6 Dec 1972 [11 Dec 1971] 57648/71 Heading B7C A pneumatic tyre has on its interior surface, in those regions thereof located radially inwardly of the widest part of the tyre, a layer 8-9 for protecting the tyre carcass formed of a rubber compound having a tear resistance of at least 500 lb. per inch thickness as measured by the A.S.T.M. standard test D624 at 20‹ C. The tear-resistant layer may increase in thickness as it extends radially inwardly from the widest part of the tyre, as shown, and may be extended to form the whole of the interior surface of the tyre (Fig. 1, not shown). The tear-resistant layer may itself be airimpermeable, or may be superposed on a layer of air-impermeable rubber, and in the latter case there may be an intermediate rubber layer between the tear-resistant and air-impermeable layers. Reinforcements of radially disposed steel cords may be provided adjacent the inner side of the tyre carcass 4 in those regions of the tyre located radially inwardly of its widest part. The tear-resistant rubber compound may be based on natural rubber and may include both carbon black and a silica filler, a specific example of a suitable composition being given in the Specification. The tyre may be of radial-ply construction and may have an aspect ratio of 50-75% and a tread width which is greater than the distance between the bead heels of the inflated tyre. The tyre may be provided in the radially outer region of each sidewall with a layer of rubber of a hardness no more than 45‹ B.S. as described in Specification 1,359,464. Specifications 1,359,461; 1,359,467 and 1,408,567 are also referred to. [GB1417968A]