GB1025174A - Improvements in or relating to the manufacture of pneumatic tyres - Google Patents

Abstract

1,025,174. Making pneumatic tyres. DUNLOP RUBBER CO. Ltd. Jan. 29, 1963 [Feb. 16, 1962], No. 5971/62. Heading B7C. A strip or pocket 6a forming a tread reinforcement and having at least two layers of rubberized parallel cords 7, 8, which cords are to extend, in the crown region of the finished tyre, at a bias angle of 5 to 30 degrees to the mid-circumferential plane, is formed initially with the cords of the layers crossing as shown and running at bias angles substantially equal to the complementary angle to the said finished bias angle, the strip or pocket then being stretched to deflect the cords to the finished bias angle. Figs. 5, 6 (not shown), illustrate the " before " and " after " orientations in the pocket of Fig. 1. A machine as in Fig. 2 (not shown), may be used to partly stretch a pocket 6a prior to fitting it to a tyre carcass, which is then expanded to toroidal shape, or a carcass may be expanded to contact with a fully stretched pocket. In the former case (Fig. 3, not shown), the pocket 6a is secured to the adjoining tyre plies, along the mid-circumferential line only, by " consolidating " locally or by spikes, to enable the cords to deflect during subsequent shaping. More than one such pocket may be used. The initial bias angle may be within 10 degrees either way of the complement of the finished bias angle. The strip or pocket is applied to a carcass on a cylindrical or crown former, but the tyre may then be completed in a diaphragm curing press.