| 摘要 |
960,558. Pneumatic tyres. PIRELLI S.p.A. Dec. 5, 1962 [Jan. 25, 1962], No. 46023/62. Heading B7C. A pneumatic tyre of the readily replaceable tread type comprises a tread ring 10 having an inextensible reinforcement 11, and a casing 12 having a carcass 13 and a breaker structure formed from two plies 14, 15 of parallel cords, the radially outer surface of the casing 12 being provided with a tread seating formed by a pair of circumferentially continuous grooves 16 which define therebetween an uninterrupted central portion of the casing to accommodate at least the radially outermost ply 14 and having an axial width equal to that of the ply 14, the radially inner surface of the tread ring 10 having a profile complementary to that of the radially outer surface of the casing 12. The radial depth of the grooves 16 does not substantially exceed the " thickness " of the ply 14, the " thickness " being the thickness of the ply 14 plus the rubber layer superimposed thereon to form the radially outer surface of the casing. In a modification the whole breaker structure is contained within the central portion of the casing, the grooves 16 being located at the axially outer edges of the structure and having a radial depth which does not substantially exceed the " thickness " of the whole structure. The grooves 16 and the corresponding ridges 17 on the tread ring 10 are symmetrically disposed with respect to the mid-circumferential plane of the tyre. |
