Long life homogeneous tyre carcass - has inner layer of porous e.g. butyl rubber made by extrusion so that it has no spliced joints to form stress concns.

摘要

A tyre carcass is coated on the inner side and its outer side is coated on the centre section and has tread and side faces. The inner side coating is cylindrical rubber tube which is free from any joints circumferentially. Pref. a tubing of butyl rubber G is extruded and is cut off into a length so as to form a cylinders for use as the inner layer concerned. This is then coated on the inner side with a release agent and fitted on to a drum, making an unjointed layer (16a). A sheet (17) of the carcass is next wrapped round it and jointed along its overlapping edges to form a cylinder (18). Its ends are pressed inwards to make necks (19) and bead-like rings are fitted on. The edges are folded over the raw tyre is formed. The rubber used for this cylinder is preferably highly porous to air-hence butyl rubber. A further advantage of the absence of overlapping spliced joints in the inner layer (16a) is that the carcass filaments are not displaced when the raw tyre is taken to the mould by moulding bags. ADVANTAGE - The construction is uniform as it is free from joints on the inside. It has a good service life as it is free from risk of peeling off and/or breaking caused by joints on the inner layer.