| 摘要 |
1407354 Pneumatic tyre breakers MICHELIN & CIE (COMPAGNIE GENERALE DES ETAB MICHELIN) 23 Feb 1973 [25 Feb 1972] 9105/73 Heading B7C A breaker 3 for a pneumatic tyre comprises a cord ply 8 having one or, as shown, both of its edge portions 11 folded about a respective circumferentially extending cord 10 which is provided in addition to the cords of the breaker ply or plies. The or each cord 10 may be of elastic material, e.g. polyamide, and may be wound round the breaker for more than one turn such that its ends overlap one another, e.g. over 10-20 cm., as indicated at the right-hand side of Fig. 1. The breaker may comprise a further, non- folded, ply 9 whose edge portions are encompassed by the ply 8. The cords of the plies 8 and 9 may cross one another, the cord angle of the ply 8 being, e.g. 26 degrees, and that of the ply 9 being, e.g. 20 degrees. The breaker may, as shown, be incorporated in a tyre having a radial ply carcass 5. The breaker shown in Fig. 1, may be made by wrapping the ply 8 and then the ply 9 around a deflated inflatable sleeve 21 on a building drum 20, laying the cords 10 on the ply 8 adjacent the edges of the ply 9, inflating the sleeve 21, as shown in Fig. 2, to tension the cords 10 and plies 8, 9, pivoting rocker arms 22 on the drum 20 in the direction shown by the arrows in Fig. 2, to initiate folding back of the ply portions 11 about the cords 10, advancing plates 31 having projecting fingers 32 up to the ends of the drum, as shown in Fig. 4, to complete folding back of the portions 11, and finally stitching the portions 11 before removing the breaker from the drum. |
