NZ202121A

NZ202121A - Optical fibre duct enclosed by embedded wires

Info

Publication number: NZ202121A
Application number: NZ20212182A
Authority: NZ
Inventors: C E Wilbud; R D Edwards; D D Jones
Original assignee: Int Standard Electric Corp
Priority date: 1981-10-20
Filing date: 1982-10-08
Publication date: 1984-11-09
Also published as: GB2107896A; GB2107896B; ES268012Y; DE3236972A1; ES268012U; AU8937782A

Description

NEW ZEALAND THE PATENTS ACT , 1953 COMPLETE SPECIFICATION "ELECTRIC CABLE" WE, INTERNATIONAL STANDARD ELECTRIC CORPORATION, a Corporation of the State of Delaware, United States of America, of 320 Park Avenue, New York 22, New York, United States of America, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement 202 t 21 This invention relates to electric cables in the form of land lines employing ducted cables and especially to ducts carrying relatively small and fragile optical cables.

Optical cables are installed in ducts for reasons of economy, environmental and mechanical protection. There may co-exist with optical communications links, the need for supervisory communications, and power for feeding repeaters all of which may most readily be supplied by the provision of metallic conductors. It is possible to make composite cables providing these features, but with a penalty in terms of cost, size weight and corresponding reduction in maximum installable lengths. Further the failure of one or more of the components may render the finished cable unsuitable for its intended purpose. These problems may be avoided by the beneficial use of an enhanced flexible duct which provides all or part of the above named functions while at the same time preserving its original usage and benefits.

According to the invention in its broadest aspect, there is provided a cable construction comprising one or more optical cables loosely contained within a flexible tubular duct which is itself surrounded by a binding sheath of plastics material in which are embedded one or more non-optical cables.

The duct so equipped may be laid and spliced separately from any optical cable (thus avoiding the problems of non-similarity in weight and length and also making replacement 202 1 easiest), and teeing off of power or supervisory circuits may be accomplished without interference to any optical cable.

The extra components that may be included for amalgamation with the flexible duct may also provide for enhance-5 ment of the mechanical and environmental parameters for an optical cable included in the flexible duct.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figs. 1, 2 and 3 show respectively three different cable constructions.

Referring to Fig. 1, a protected optical cable 1 is loosely contained within a flexible duct 2. The duct is, in turn, surrounded by a binding sheath 3. In the sheath 3 are 15 embedded two non-optical communications cables 4. These are in the form (in this case) of quad-cables of which all four metallic conductors 5 are separately insulated and surrounded by their own sheath 6.

The flexible duct 2 and the binding sheath 3 are formed 2 0 by extrusion of conventional thermo-plastics materials such as polyethylene.

In the embodiment shown in Fig. 2, four bare conductors are directly insulated by being buried in the binding sheath 3. These conductors could be used for communication purposes 25 or the supply of power. 2 02 t 2 i In Fig. 3 is shown a composite cable construction in which the binding sheath 3 has embedded therein both bare conductors 7 and strength members 8. The latter may be of any high strength material (e.g. steel, glass, aramids or carbon fibres) and may be laid straight or helically and oversheathed to bind the structure).

The binding sheath 3 may itself be protected to exclude liquids or vapours by means of a vapour barrier 9 in the form of an overlapping metal/plastics laminate tape 9 sealed at the overlap 10. Preferably the tape 9 is surrounded by a final sheath 11 which will, of course assist in sealing the overlap 10. The sheath 11 may be of a material selected for its co-efficient of friction or its resistance to abrasion.

Claims

20212t What we claim is:

1. A cable construction comprising one or more optical cables loosely contained within a flexible tubular duct which is itself surrounded by a binding sheath of plastics material in which are embedded one or more non-optical cables.

2. A cable construction as claimed in claim 1 in which the non-optical cables are telecommunications cables or conductors.

3. A cable construction as claimed in claim 1 in which the non-optical cables are power-supply cables or conductors.

4. A cable construction according to any one of the preceding claims in which the sheath is reinforced by the inclusion therein of one or more strength members.

5. A cable construction according to any preceding claim in which a screen of metal tape or laminate is wrapped around the duct in an overlapping manner and held in place by the sheath.

6. A cable construction substantially as described with reference to the accompanying drawings. INTERNATIONAL STANDARD; ELECTRIC CORPORATION P.M. CONRICK Authorized Agent 5/1/1223 - 5 -