GB958367A - Closed moulds for casting gaskets on pipe ends - Google Patents

Abstract

958,367. Pipe couplings; non-metallic pipes. MINNESOTA MINING & MANUFACTURING CO. June 28, 1960, No. 22649/60. Headings F2G and F2P. [Also in Division B5] A mould for casting annular gaskets in situ on the ends of pipe sections comprises an expansible body for insertion into the end of a pipe section, mechanism for expanding the body into engagement with the pipe section and releasing it, an annular gasket forming member disposed concentric with but spaced from the pipe section and held in position by the expansible body, and injection and vent openings for the admission of a gasket forming heat curing resin and to permit the escape of air. In the case of the spigot end 34 of a pipe section 36 (Fig. 3), the expansible body may be a rubber disc 14 mounted between plates 22, 28 on an axial stud 16, the inner end 18 of which is threaded and carries an adjusting nut 20. The annular gasket forming member 30 has an inturned flange 32 which is held between the spigot end 34 and the plate 28, the disc 14 being expanded radially to centre and hold the annular member 30 by the plates 22, 28 being drawn together on operation of the cam 24. Cam 24 is pivotally mounted on the end of stud 16 and operated by means of lever 26, and the initial diameter of the disc 14 may be controlled by means of the adjusting nut 20 prior to the operation of the cam 24. The mould cavity 48 between the pipe section 36 and the annular member 30 is sealed by means of an O- ring 46. For moulding gaskets in the socket end 54, a similar mould is used (Fig. 4) but in this case the expansible body 56 has a flange 70 at its outer end which seals the mould cavity 82 formed between the annular gasket forming member 78 and the pipe section 36, the injection and vent openings 86, 88 passing through this flange. The annular member 78 is spaced axially from the socket shoulder as at 84, so providing a resin surface to offset dimensional differences which often occur between interfitting spigot and socket ends. In place of a rubber expansible body, a vacuum contractible body which expands upon release of the vacuum, an inflatable bladder, or a mechanical expansible assembly carried by the mould structure could be used. An advantage of using closed moulds over the commonly used open moulds is that vitrified clay pipes are normally stacked in horizontal layers as they are removed from the kiln and the above-described moulds can be mounted on such pipes without disturbing them. They are also useful with fittings such as Y's, T's and elbows as the angular positions of the pipe ends is immaterial.