| 摘要 |
<p>613,178. Wheel tyres. FIRESTONE TIRE & RUBBER CO. June 14, 1946, No. 17902. Convention date, July 30, 1945. [Class 144 (ii)] A tyre tread comprises continuous circumferential ribs 13 ... 17 spaced by zig-zag grooves 18, the angles of the recesses 20 being different from those of the projections 24 so that, under load, the wider portions of the grooves in the ground-engaging zone of the tread are prevented from completely closing. As will be seen from Figs. 4 and 5, any surface water &c. under the actual tread can escape through the open portions 9 and the bottoms of the grooves 18.</p> |
