GB938797A - Improvements in or relating to the manufacture of vehicle tyres - Google Patents

Abstract

938,797. Tyre curing bags or diaphragms with internal ribs. MACBETH PATENTS Ltd. Sept. 5, 1961 [June 7, 1960; Aug. 12, 1960], Nos. 19899/60 and 27949/60. Class 87(2). Improved heat transfer during vulcanisation of tyres is obtained with a thin walled bag, Fig. 3, or diaphragm member Fig. 1 (not shown), possessing interior ribs or other projections 12 to prevent wrinkling on folding. Joint faces 13 of the bag either in or offset but parallel to the circircumferential plane may have co-acting recesses and projections. Heated pressurised air or other fluid may be circulated through diametrically opposed openings having valves, Fig. 2 (not shown) or oppositely disposed axially extending openings 15, one pair of which on one side of member 10, registers with studs 16 on the ejector or clip ring of the tyre mould; the other pair connected to passages 17 for fluid circulation. The member 10 may be of natural or synthetic rubber and, if the former, the faces 13 may be jointed with solution prior to final cure. During tyre moulding an unvulcanised joint 13 is sustained by the fluid pressure upon projections 18 into the bag. The projections 12 may comprise ribs in two sets, each set in parallel relationship and transverse to the other or ribs formed between holes or studs or other projections. A suitable diaphragm, Fig. 1 (not shown) may be moulded upon a core or jointed from an extruded section to the required ring. Specification 728,160 is referred to.