RADIAL TYRE AND TO PROCESSES FOR MANUFACTURING A RADIAL TYRE

摘要

1496517 Pneumatic tyres INDUSTRIE PIRELLI SpA 22 Oct 1974 [6 Nov 1973] 45754/74 Heading B7C A radial tyre comprises two plies 4, 5 of parallel metal cords with the cords of the plies crossing and making cord angles between 10-35 degrees with the mid-circumferential plane x-x, and, radially outwardly of the metal cord plies, a ply 6 of parallel textile, e.g. nylon, cords making a cord angle of 0 degrees with the midcircumferential plane. The material of the textile cords is such that it reduces in length when heated during tyre manufacture. The textile cord ply over at least part of its axial width comprises cords cut transversely of the tyre at intervals along the circumferential length of the cords. Preferably the intervals are not greater than 1/ 10 , and preferably 1/ 100 -4/ 100 , of the circumferential length of the cords. In the embodiment, of Fig. 2 the central region of the textile ply 6 is provided with equi-spaced cuts 9. In an alternative arrangement (Fig. 3, not shown), equi-spaced cuts (12) are also made in the lateral regions of the textile ply. The cuts 9 may be orientated in the range 45-90 degrees to the plane x-x. In the manufacture of tyres of the above type, a rubberized strip of parallel textile cords is prepared in which the cords extend parallel to the length of the strip and are continuous. The strip is attached to an extruded band, of green, tread material. Transverse cuts are made in the strip, each cut only extending across part of the width of the strip. A required length of tread material is then cut from the band and strip assembly and applied to a green tyre carcass already provided with metal cord plies 4, 5. In alternative methods, the cuts may be made in the strip prior to the strip being united with the green, tread band, and the strip and tread band may be cut to length prior to their assembly.