GB1364426A - Pneumatic tyres - Google Patents

Abstract

1364426 Pneumatic tyres DUNLOP HOLDINGS Ltd 7 Sept 1971 [11 Sept 1970 17 Nov 1970] 43475/70 and 54520/70 Heading B7C A pneumatic tyre has a breaker assembly including a breaker 10 with folded edges; the breaker 10 consisting of one or, as shown in Figs. 1 and 3, two folded strips 11, 12 of rubberized parallel cord fabric and individual stiffening strips, e.g. 13-16, for the folded edge regions only of the breaker 10, each stiffening strip having a width substantially less than that of the breaker 10 and being made of a material whose modulus of elasticity is greater than that of the cord fabric of the breaker 10. The cords of the strips 11, 12 may be of rayon and disposed at a cord angle of 10-25 degrees. Each folded edge region of the breaker 10 may be provided with two layers of stiffening strip, the two layers either being provided by two separate stiffening strips, e.g. 13, 14, of cord fabric, as shown in Fig. 1, or by a single folded strip, e.g. 19, of cord fabric which may be located outside, as shown in Fig. 3, or inside (Fig. 2, not shown) the fold of the associated folded edge of the breaker 10. In the above described cases of two stiffening strip layers at each edge of the breaker 10, the axially inner edge of one layer may lie axially inwardly of that of the other layer, the cords of the two layers may be of steel or glass and cross-laid at a cord angle equal to or less than that of the strips 11, 12, and, in each layer, the cords may cross, or lie parallel to, the cords in the adjacent part of the respective strip 11, 12. The breaker 10 may alternatively have a single unfolded strip (21) of woven nylon mesh at each edge (Fig. 4, not shown), the cords or fibres of the mesh being disposed at a cord angle of 45 degrees. The stiffening strips may together occupy up to 70% of the axial width of the breaker 10, and one edge of the breaker 10 may be provided with a stiffening strip of different width or stiffness to a stiffening strip provided at the other breaker edge so as to create a tyre with asymmetrical properties. The breaker assembly may comprise further breakers consisting of single plies of reinforcing cords, and the tyre carcass may be of radial-ply construction and formed of metal, rayon, polyester or nylon cord fabric.