| 摘要 |
1489587 Tyre treads BRIDGESTONE TIRE KK 30 Oct 1974 [22 Nov 1973] 46931/74 Heading B7C A pneumatic tyre tread having blocks arranged in transverely extending, circumferentially spaced rows comprises at least two different tread patterns A, C portions of said at least two patterns being segmentally arranged such that each half of the tyre tread circumference is provided with at least one portion of each of the two patterns. One of the two patterns (i.e. A) has transverse grooves and blocks which are wide in the circumferential direction while the other pattern C has transverse grooves and blocks which are narrow in the circumferential direction. The amount of tread rubber per unilength over at least one tenth of the circumference of the tread is substantially equal to the amount of tread rubber per unit length over any other such part of the tread, Figs. 1 and 3 show a tread comprising three patterns A, B, C with the portions of patterns A, B, C arranged as illustrated, and with # A ># B ># C . Preferably # A =20 degrees, # B = 16 degrees and # C =12 degrees, and l C /l A is in the range 0À4 to 0À8. The Specification discloses other sequences of the portions of patterns A, B, C: and sequence of the portions of the two patterns A, C. |
