GB802268A - Improvements in or relating to pneumatic tyres - Google Patents

Abstract

802,268. Pneumatic tyres. DUNLOP RUBBER CO., Ltd. June 21, 1956 [July 5, 1955], No. 19341/55. Class 144 (2). To reduce the tendency to " break away " of the tyres during cornering of a vehicle, a pneumatic tyre is provided with smoothly rounded shoulders 6 which in cross-section provide a continuous smooth curve with the tyre crown 7, and a circumferential knife cut, or series of knife cuts 9, are formed in each shoulder, the or each cut 9 being inclined for the major portion of its length at an angle of from 30 to 60 degrees to the mid circumferential plane of the tyre. As shown, the shoulders 6 each have a series of cuts 9 which extend from their axially outer portions to the adjacent grooves 3 separating the shoulders from the inner tread ribs 2 at an angle of 60 degrees to the circumferential, each cut 9 being linear except for a central V-shaped portion. In an alternative arrangement, a single circumferential zig-zag cut may be provided, the branches of which extend at 45 degrees to the circumferential and the corners of which are rounded. Fig. 4 shows a further arrangement wherein the shoulder cuts are arranged in a repeating series, each series comprising alternating long, intermediate and short cuts 13, 15, 14 respectively with the cuts 15 connecting into the adjacent rounded peak portions 11c of a 45-degree zig-zag circumferential cut 11.