Patent GB-856728-A (GB)
Title: Improved wire-reinforced hose and method for production thereof
IPC: B29D23/00
Filed: 1958-01-17
Abstract: 856,728. Flexible reinforced hose pipes. GOODRICH CO., B. F. Jan. 17, 1958 [April 11, 1957], No. 1678/58. Class 99(2). A flexible wire reinforced hose comprises a tubular wall having at least two concentric helical wire plies of opposite hand incorporated therein each wire ply being formed of a multiplicity of individual resiliently flexible wires disposed in parallel helical convolutions about the longitudinal axis of the hose, all the wires of at least the outermost wire ply being prestressed so as to engage in resilient gripping contact with the underlying adjacent portions of the tubular wall. As shown the hose structure includes a fluid-tight rubber tube 10 (e.g. neoprene) surrounded by a wall which includes four wire reinforcing plies identified by the reference numerals 12, 13, 14, 15. The wire plies are associated with layers of rubber or rubbertreated non-metallic fabrics 18, 19 and 20. The exterior of the carcass is enclosed by a rubber cover 22. Each of the wire plies is composed of a multiplicity of individual fine high-tensile wires. The wires are preferably standard monofilamentary high-tensile strength cold drawn spring steel wire. The so called " music " quality wire having a tensile strength at the yield point of about 300,000 to 425,000 lbs/sq. in. and ranging from about À010 in. to about - 030 in. in diameter may be used advantageously It may be convenient to use the same number of wires in each ply and in the outermost plies the wires will be spaced apart slightly more than the wires of the innermost plies. Preferably more than about 90% up to 100% of the underlying surface is covered by each ply. The fabric 17 is a coarse cloth. It is slit to a tape and wound helically with its edges abutting. The layer 18 comprises a helically wound tape of cloth impregnated with rubber on both sides. Layers 19 and 20 are of rubber. The outer wire ply 15 may serve as the outer covering of the hose. As shown a serving of textile cords 21 such as cotton or nylon is wound helically about the outer wire ply 15. Preferably these cords are impregnated with a rubber material. The outer rubber cover 22 may be extruded or wound on in the form of a tape. The complete hose may be cured in open steam vulcanisers either exposed or encased in lead or a textile wrapper. The outer wire ply 15 is applied so that it tends to exert a gripping or constructing resilient pressure on the underlying portions of the hose. The pitch of the neutral lay is preferably slightly less than the pitch of the wrapped convolutions. The pitch of the neutral lay should be greater than 50% of the pitch of the wrapped convolutions. In some instances all the plies may be so constructed that all of them will tend to construct the underlying layers either equally or to a lesser extent in the innermost ply on plies. On the other hand it is advantageous under certain conditions to form the innermost ply so that it tends to expand slightly. This is accomplished by shaping the wires so that the length of one complete neutral convolution is slightly longer than the length of one complete wrapped convolution. Fuller details are given of specific constructions of hoses. A hose having two wire plies is described. The hose may have six or eight wire plies. The angles at which the wires of the several plies are wrapped average about 55 degrees. The wires may be washed and dipped in a suitable adhesive to coat the wires in accordance with the usual technique of bonding rubber to the metal before wrapping them on the hose carcass. The term rubber used in the specification includes natural rubber and various synthetic materials which are or may be compounded to impart the characteristic flexibility and extensibility of rubber. The rubber materials used in hydraulic hoses are normally oil-resistant rubbers known as neopene or nitrile rubber compounds. Successive wire plies may be insulated from each other by plastics. The central tube may be of plastic material. The shaping of the wires is effected by bending the converging portions of the wires over suitably contoured surfaces under sufficient tension to cold work the wires and impart the desired permanent helical set to all the wires simultaneously. The machine for making the hose is described. The machine is also described in Specification 848,524 referred to.