| 摘要 |
893,414. Tyre treads. DUNLOP RUBBER CO. Ltd. Sept. 16, 1959 [Sept. 23, 1958], No. 31536/59. Class 144 (2). A pneumatic tyre tread 1 comprises a central groundcontacting surface of transversely smooth convex curvature flanked on each side by a shoulder region 3 comprising at least a pair of side-by-side circumferential ribs 4, 5 or rows of blocks, or one of each, each rib or row having lateral projections 4a, 5a, respectively, which extend towards corresponding indentations 5b, 4b in the other, and the ground-contacting surface of the rib or row of blocks nearer the sidewall 2 in each shoulder lying either radially inwardly or outwardly of the line of curvature of the smoothly-curved central portion. For singletrack vehicles, such as motor-cycles, the rib 4 (or row of blocks) immediately adjacent the sidewall 2 lies radially outwardly, whereas for double-track vehicles it lies radially inwardly as shown. The pair of ribs or rows may be bridged as at 10b and the axially inner rib 5 (or row of blocks) may be connected to the smoothly curved crown by bridging-portions 10. The projections of the ribs or rows of blocks may be irregularly spaced to reduce running noise, and stepped or shouldered formations may be provided on the radially outer surface of a rib or row. Notches and/or knife cuts may be provided in a rib or row to improve road grip. Three such side-by-side circumferential ribs or rows of blocks may be provided in each shoulder, the radial height thereof successively increasing from the sidewall towards the crown. |
