Improvements in or relating to the production of resilient rubber rings and articles embodying same

摘要

A ring of rubber or like elastomer reinforced with an embedded annular spring is made by supporting the spring in an annular mould, injecting rubber or the like, at least partially vulcanizing the rubber, and subsequently inserting the coated spring in a mould of larger dimensions, injecting more rubber and finally vulcanizing the whole. The ring may be supported centrally in the first mould on grooved projections, the second moulding operation covering inter alia those parts left uncovered in the first operation. Alternatively, the spring may be supported by rubber supports which are embedded in the covering by the moulding operations. The spring may be of flat section coiled into an annulus or may be a helical spring bent into a circle and secured. If of the latter form the spring may be supported on a spigot in the first mould and rubber injected into its interior, the rubber exuding through the turns to fill the mould. Either type of spring may also be supported in the first mould by rubber tape would round it in an open helix, rubber being injected into the centre of the spring when this is of helical form. Articles incorporating reinforced rubber rings are made by disposing the coated ring from the first operation in that part of a mould of the required shape corresponding to the part of the moulded article requiring reinforcement. The rubber mix for the second operation may be faster curing than that for the first, so that in the second operation both may be fully cured in the same time.