GB969891A - Improvements in resilient diaphragm manufacture - Google Patents

Abstract

969,891. Resilient diaphragms. DUNLOP RUBBER CO. Ltd. Jan. 10, 1961 [Jan. 19, 1960; May 14, 1960], Nos. 1819/60 and 17106/60. Heading F2S. In a method of manufacturing a resilient diaphragm of the rolling- lobe type a cord 33 of textile material, e.g. nylon, is wound alternately over axially-aligned notches 31 in end and guide plates 13, 15 on end members 11 urged apart by a spring 24 and mounted coaxially on a central rod 12 of a forming spool 10 to form a cylindrical sock, the end members 11 are twisted relative to each other through a predetermined angle so that they approach each other against the action of the spring 24 and produce a neck in the sock, and the latter is treated, e.g. by dipping into latex or rubber solution, so that it remains in a twisted condition on removal from the spool. In one process a ply of uncured rubber 32 is first applied to the end members 11 so that the cord 33 beds into it when the neck is formed a further ply 34 of cured rubber being added and the plies then being rolled. After rolling the cords 33 are either cut, or unhooked from, the ends 11 and the sock is pulled off the spool 10 one half 35 being fitted over a first former (Fig. 6) and the other half 36 being drawn down over a bead wire 38 the space 39 being filled with a rubber strip and the halves 35, 36 being consolidated by rolling. The member 35, 36 is removed from the former 37 and inserted in a cavity 40 in a second former 41, Fig. 7, the members 35, 36 then being drawn down over a ridge 42 and the free ends folded back over a bead wire 43 and rolled. The space 44 is filled with a strip of rubber and the member 35, 36 is then removed from the former 41 and placed into a mould for curing by heating. The two end members 11 each consist of a pair of end and guide plates 13, 15, cylindrical and tapering members 14, 16 all secured together by screws 18 the lower end member 11 being non- rotatably located by a pin 46 on the lower end of the rod 12 the upper end of which carries a locking mechanism 28, 29 which frictionally engages the surface of a bore 26 in the upper member 11 when a nut 20, engaging the threaded upper end of the rod 12, is tightened. Release of the nut 20 allows the upper end member 11 to rotate the spring 24 urging the members axially apart. The number of cords may be increased to be as close as required at the neck of the sock.