IE35935B1 - Improvements in or relating to pneumatic tyres - Google Patents

Abstract

1366300 Pneumatic tyre treads DUNLOP HOLDINGS Ltd 16 Nov 1971 [21 Nov 1970] 55457/70 Heading B7C A pneumatic tyre has a tread comprising two undulating endless circumferential grooves 2, 3 each of which has a proportion, e.g. 10-50% of its length lying substantially normal to the mid-circumferential plane of the tyre, a tread element, e.g. a rib, or, as shown, tread elements, e.g. blocks 4, between the grooves 2, 3, and a tread element, e.g. a rib, or, as shown, tread elements, e.g. blocks 5, located between each groove 2, 3 and the adjacent shoulder of the tyre and disposed to form an interlock pattern with the element or elements between the grooves 2, 3, at least the or each tread element between the grooves being provided with generally axially disposed slots or slits 10 whereby, in use, the element or elements is or are more readily flexed circumferentially than axially of the tyre. In the illustrated embodiment each block 4 is defined by a complete undulation in the groove 2, an adjacent complete undulation in the groove 3, and grooves 6 connecting the grooves 2, 3. The blocks 5, which are separated by grooves 9, each have a portion 7 whose axially outer edge tapers to merge into the associated tyre shoulder. Generally axially disposed slots or slits 8, 11 are also provided in the blocks 5, and there may be sipes 12 in both the blocks 4 and 5. Some of the blocks 4 or 5 may be linked by tie-bars. The grooves 2, 3 may be in phase with one another, as shown, or out of phase, e.g. of exactly opposite phase, and may merge into one another at spaced points. Each groove 2, 3 may be of wholly or partly curved configuration or of multi-faceted form. Holes may be provided in the tread for the insertion of ice-studs, and the tyre may have a radial carcass with a braced tread. [GB1366300A]