GB987321A - Flexible conduit and method of manufacture - Google Patents

Abstract

987,321. Flexible tubes. DAYCO CORPORATION. March 14, 1963 [April 17, 1962], No. 10209/63. Heading F2P. A flexible relatively inextensible externally corrugated conduit comprises an internal reinforcement having axially spaced turns, an elastomeric member embracing the reinforcement and a relatively non-stretchable formedin-place braided fabric cover which embraces said member and exerts a radially inward force against said reinforcement unifying the resulting assembly, the elastomeric member and cover partially surrounding said turns and extending inwardly therebetween. As shown in Fig. 1, elastomeric material 14 is forced from a tube-extruder 13 around a coil 11 of reinforcing material, e.g. rubber-covered metal or plastic, or wholly thermoplastic, and forms the elastomeric tube 16 around a coil 11 driven in the direction of the arrow by known means. The reinforced tube is then led to a braiding machine 17 (the 90 degrees here shown has no special significance) and films, e.g. nylon, cotton &c., wound from spools 18, 19 which are mounted on a rotating ring. Braiding 22 is thus applied to the tube with a compressive force that forces the elastomeric material between the turns of the coil and so produces corrugations. The reinforcement may be helical, as shown, or may be a series of separate rings around a compressible mandrel. Instead of the tube 16 being formed by extrusion an existing tube 26, Fig. 3, may be placed in a vacuum chamber 25, embracing a reinforcing coil 23 on a compressible mandrel 24, and collapsed on the coil, thereby becoming corrugated. As shown in Fig. 6, the ends 30 of two hollow cylinders 27, preferably of the same material as the tube 26, may be inserted in the ends of the reinforcing coil 23 and vacuum applied, after which the tube, so corrugated, and the cylinders 27 are braided, Fig. 7. The product is cut into lengths by severing the cylinders in the middle by a cutter 31. The surface may then be sprayed, from a nozzle 34, with rubber or other plastic material. The inner and outer surfaces of the product may be coated with elastomeric material by dipping, for example. Specifications 761,212, 782,541, 813,700 and 867,836 are referred to.