GB381658A - Improvements in or relating to the manufacture of pneumatic tyre covers - Google Patents

Abstract

381,658. Cores for moulding tyres. VIDALE, G. and SOC. ITALIANA PIRELLI, 21, Via Fabio Filzi, Milan, Italy. Aug. 14, 1931, No. 23013. [Class 87 (ii).] In the manufacture of covers for pneumatic tyres of the super-balloon type wherein the cover is built up on a removable core, the core is rigid and readily disintegratable and is cast or moulded from a plastic mix. It may be made of a waterdispersible inorganic colloid such as a water-dispersible chalk or clay, e.g. smectic or smectitic clays, kaolins, bentonite or argill aceous sands such as moulding sand. A sawdust &c. filler may be used, together with a binding agent unaffected by the vulcanizing temperature, such as an emulsoid colloid, as gum arabic or casein. The core 1 is first moulded from the plastic mix, if necessary with reinforcing wires 2 incorporated. A metal annulus 3 may be provided to form a sheathing and support for the tyre beads. The core is then removed from its mould, dried, and covered with flexible material such as paper or thin textile fabric. The core is then placed on a support 4 and layers of fabric and rubber built up on it. The core and cover may be dismounted from their support and immersed in water to effect the disintegration and removal of the core. The cover may then be distended by air bags and vulcanized, as within a mould in an autoclave press, or the cover may be vulcanized in situ on the core. Specification 350,227 is referred to.