Tread for long life non-skid summer tyre - has circumferential rows of blocks divided by curving transverse grooves and blocks on opposite sides of centre line are offset

摘要

A tyre tread has a number of circumferential rows of profiled blocks sepd. by circumferential grooves, in which the individual blocks of each row are divided also by transverse grooves; in both the left and the right hand halves of the tread these last transverse grooves are aligned with each other in such a way that their centre lines meet the edges of the tread at between 3 and 15 deg to the axes, and the centre lines of those grooves in the centre rows of blocks meet the axes at between 15 and 50 deg, so that the transverse grooves altogether form a pattern of extended "S" lines; the centre rows of blocks consist of a sequence of alternating "S" and "T"-shapes. The figure shows an example, with the blocks in rows (3-10), including those (3,10) at the shoulders. Their shape depends upon whether they are outermost (3,10), intermediate (4) or centre (6,7). The last (19.6, 19.7) alternate together and in their own rows between "S" and "T" shapes. Grooves (12) have half normal depth. Transverse grooves (18) are of full depth but the circumferential grooves (12) are shallower between them (18) and are also bent. The grooves (13) have full depth and twice the width of grooves (12). Along the centre circumferential groove (14) the transverse grooves do not meet but are offset from each other by 20%. A typical transverse line (23) is shown, which meets the edges (22) at 5 deg to the axis but meets the zenith line at about 35 deg to the axis.