GB952714A - Improvements in and relating to flexible conduits - Google Patents

Abstract

952,714. Flexible conduits. ACME-HAMILTON MANUFACTURING CORPORATION. Oct. 16, 1962 [Oct. 18, 1961], No. 39171/62. Heading F2P. A flexible conduit comprises a helical reinforcement having longitudinally-spaced convolutions and an enclosing cover therefore consisting of braided, contractile, plastic monofilaments, the cover being shrunk in situ to provide helical wall portions extending radially inward between successive convolutions of the reinforcement, the latter being in unbonded relation to the cover and non-displaceable relative to the cover upon flexure and twisting of the conduit. As shown, the precoiled reinforcement is of aluminium, steel or coppercoated steel wire, or a plastic such as polypropylene, and the cover monofilaments are of linear polyethylene, polypropylene, nylon or other tough plastic material having a high modulus. There may be an inner and/or outer sheath, of vinyl copolymer or polyvinyl chloride pigmented to a selected colour, or colourless and transparent; a helical space 32, Fig. 5, is provided between the braided cover and the sheath. The braided cover 13 may be rendered impervious to fluids by applying to the inner surface thereof a plastic coating in the form of a plastisol or organosol of vinyl copolyer, polyvinyl chlorides or polyvinyledene chloride or the monofilaments may be close braided and fused together. The reinforcement may comprise a pair of electrical conductors coiled helically in side-by-side relation and retained in insulated relation by the corrugation of the cover; alternatively, the wires are coated with polyvinyl chloride. The spacing between the braided monofilaments may be increased so that upon heating of the conduit assembly the sheaths 36, 37, Fig. 8, may be adhered together. In making the conduit, the helix 11 is moved upwardly from a coiler 15 to a braider 17 to pass through a nipple 19 on which the monofilaments are braided, the resultant braided covering passing through a stabilizing ring 19A. The assembly of helix and cover is passed through a hot-air-circulating oven to produce contraction of the braided covering and the helical wall portion 25.