GB892654A - Reinforced flexible conduit - Google Patents

Abstract

892,654. Flexible conduits. DAYCO CORPORATION. March 29, 1960 [April 20, 1959], No. 11073/60. Class 99(2). A reinforced flexible conduit, Fig. 8, particularly for use in vacuum cleaners, respiratory devices or cooling systems, comprises a helical reinforcement 11 having disposed concentrically therewith a tube 15 of elastomeric material and an unstressed, longitudinally stretchable tubular fabric reinforcing member 17. A further tube 18 of elastomeric material may be inserted on the member 17. The tubes 15, 18 may be of vinyl or polyethylene. The reinforcement 11 consists of plastic coated wire. The member 17, in the form of a knitted, woven or braided stockinet, may be made of cotton, rayon, nylon, acetate, acrylic or polyester fibres or of a mixture of these fibres. The fibres may be treated with a vinyl compound. As shown in Fig. 3, the conduit is made by winding the reinforcement 11 on a perforated mandrel 12, introducing the mandrel in a vacuum box 13, as described in Specification 867,836, in which the tube 15 has been expanded and releasing the vacuum force so that the tube is made to closely envelop the reinforcement. The tube 15 may be coated with an adhesive and the stockinet 17 is then pulled over the assembly which is again introduced in the vacuum box for the application of the tube 18 thereon. The conduit is then placed in a hot air curing oven 19, Fig. 6, where corrugations are formed by applying a vacuum to the hollow interior of the mandrel 12 through a vacuum line 22 connected thereto. Depending on the temperature and also whether adhesive has been applied to the tube 15 or whether the stockinet is coated completely or on one surface, the tubes and the stockinet are bonded to each other and to the reinforcement 11 only at the areas of contact between the coils and the stockinet, or a complete bond occurs along the contacting surfaces of the tubes and stockinet, or again all components are fused into a unitary mass. In other forms of the invention the tube 18 is dispensed with and the stockinet 17 is applied either over the tube 15 or directly over the reinforcement 11. In an alternative method of manufacturing the conduit of Fig. 8, the stockinet 17 and the tubes 15, 18, Fig. 14, are placed on the mandrel 12 so that their ends extend beyond the ends of the reinforcement 11 and air is blown by means of an air hose 26 into the interior of the mandrel so as to raise the assembly of tubes and stockinet from the mandrel, allowing them to shrink until their ends are in alignment with the ends of the reinforcement. Specifications 761,212 and 782,541 also are referred to.