| 摘要 |
1388853 Pneumatic tyres DUNLOP Ltd 28 Feb 1972 [11 March 1971] 6636/71 Heading B7C A radial-ply carcass pneumatic tyre, for heavy goods vehicles, comprises a breaker, and a bead, integral with the carcass and breaker, whose shoulder regions are each divided into circumferentially spaced blocks, e.g. 10, by substantially axial grooves, e.g. 15, connected at their inner ends by a circumferential groove, e.g. 14, such that each block extends inwardly from the associated tread edge to terminate inwardly of the closer edge of the breaker, the tyre being of any size quoted in the table below and having a tread rubber thickness (as measured between the tread ground-contacting surface and the radially outermost surface of the breaker) which is at least of the order of 15% greater than the value given in the table below for that size of tyre. Tyre size Tread rubber thickness (mm.) 7À50 Î 20 18À5 8À25 Î 20 19À5 9À00 x 20 19À5 10À00 Î 20 20À5 11À00 Î 20 23À0 12À00 Î 20 24À0 In the illustrated embodiment the tread has a central circumferential groove 13 dividing the central part of the tread into two ribs 8, 9, all the tread grooves being of zig-zag form, and axial zig-zag slots 17, 18 in the ribs and circumferential zig-zag slots, e.g. 20, in the blocks being provided. Specific examples of suitable thicknesses for the tread and of suitable widths for the substantially axial shoulder grooves are given in the Specification. The tyre carcass may consist of a single ply of steel cords and the breaker may comprise three plies of steel cords. |
