GB2090995A - Pressure-resistant Cable Strength Member - Google Patents

Abstract

A communication cable to be used in a hostile environment needs to be protected from that environment, this being especially the case for an optical fibre cable for use in submarine conditions. To provide such protection, an optical fibre package, which may include one or more optical fibres is layed within a hollow tubular member which acts as a pressure-resistant and load-carrying member. This member is made from at least one layer of stranded wires, which layer may include alternate round cross-section wires (1) and waisted cross-section wires (2). The fibre package is in the central tunnel (3), and may be of such length relative to the tubular member as to be slack. It is noted that other cross-sections for the wires can be used as long as each layer is a complete tube, and that adjacent wire layers can be wound helically with opposite lays. <IMAGE>

Description

SPECIFICATIONCable Strength MemberThis invention relates to a pressure-resistant and load-carrying tubular member, such as may be used to carry a communication cable, such as an optical fibre package.

Where a communication cable is required to withstand a hostile environment, e.g. when it is a submarine cable, it is usual to provide the cable with strength members so that the cable proper is not subject to excessive strain. Although this may be important in the case of metallic conductors, it is even more important in the case of optical fibres.

An object of the invention is to provide such a tube for use in conjunction with a communication cable, such as (but not limited to) an optical fibre cable package.

According to the invention there is provided a pressure-resistant load-carrying tubular member, for use for supporting a communication cable which includes at least one stranded layer formed of adjacently-arranged wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported.

According to the invention there is also provided a pressure-resistant load-carrying tubular member, for use for supporting a communication cable such as an optical fibre package, which includes at least one stranded layer formed of alternately-arranged roundsection and waisted-section wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported.

An embodiment of the invention will now be described with reference to the accompanying drawing, which is a cross-section of a tubularmember embodying the invention.

The drawing shows a tube made up of twolayers each of which consists of alternatelyarranged round-section wires such as 1 and waisted-section wires such as 2. With a suitable cross-section for the waisted wires, which as shown differ for the two layers, each layer when stranded up, is a substantially complete cylinder.

The tubular member thus formed has a hollowcentral tunnel 3 which extends throughout itslength in which the cable to be supported isreceived.

It will be appreciated that the layers of wiresused to form the cylinder could have other crosssections, but the arrangements shown are thepreferred ones. Further, the layers can each havetheir wires arrangement helically, the wires thenbeing given alternate left-hand and right-handlays. This results in the tube thus produced beinga torsionally-balanced strand.

When the tubular member is used to support and contain an optical fibre package, which may contain one or more optical fibres, the fibre or fibres may be so arranged as to be slack. That is the fibres are each somewhat longer than the tubular member to ensure that they are not subjected to any strain.

The outer-layer may be surrounded by one or more layers of water-resistant material, if desired.

Claims

1. A pressure-resistant load-carrying tubular member, for use for supporting a communication cable, which includes at least one stranded layer formed of adjacently-arranged wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported.

2. A pressure-resistant load-carrying tubular member, for use for supporting a communication cable such as an optical fibre package, which includes at least one stranded layer formed of alternately-arranged round-section and waistedsection wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported.

3. A member as claimed in claim 1 or 2, and which has at least two layers of stranded wires.

4. A member as claimed in claim 3, and in which adjacent layers of stranded wires have their wires arranged helically with opposite lays.

5. A pressure-resistant loadcarrying tubular member, for use for supporting a communication cable, substantially as described with reference to the accompanying drawing.

New Claims or Amendments to Claims filed on 21 May1981 Superseded ClaimsNew Claims: 6. A pressure-resistant load-carrying member for use for supporting an optical fibre cable package, which member includes two stranded layers each formed of alternately-arranged roundsection and waisted-section trapezoidal wires stranded together to form a complete hollow tubular member, in which the round-section wires in the two layers are staggered with respect to each other, and in which the internal crosssection of the inner one of said two tubular members is such as to accommodate the optical fibre cable package to be supported.

7. A member as claimed in claim 6, and in which adjacent layers of said stranded wires have their wires arranged helically with opposite lays.

8. A submarine optical fibre cable which includes a pressure-resistant load-carrying member as claimed in any one of claims 1 to 7, and an optical fibre cable package inside the hollow layer or the innermost hollow layer.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Cable Strength Member This invention relates to a pressure-resistant and load-carrying tubular member, such as may be used to carry a communication cable, such as an optical fibre package. Where a communication cable is required to withstand a hostile environment, e.g. when it is a submarine cable, it is usual to provide the cable with strength members so that the cable proper is not subject to excessive strain. Although this may be important in the case of metallic conductors, it is even more important in the case of optical fibres. An object of the invention is to provide such a tube for use in conjunction with a communication cable, such as (but not limited to) an optical fibre cable package. According to the invention there is provided a pressure-resistant load-carrying tubular member, for use for supporting a communication cable which includes at least one stranded layer formed of adjacently-arranged wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported. According to the invention there is also provided a pressure-resistant load-carrying tubular member, for use for supporting a communication cable such as an optical fibre package, which includes at least one stranded layer formed of alternately-arranged roundsection and waisted-section wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported. An embodiment of the invention will now be described with reference to the accompanying drawing, which is a cross-section of a tubular member embodying the invention. The drawing shows a tube made up of two layers each of which consists of alternatelyarranged round-section wires such as 1 and waisted-section wires such as 2. With a suitable cross-section for the waisted wires, which as shown differ for the two layers, each layer when stranded up, is a substantially complete cylinder. The tubular member thus formed has a hollow central tunnel 3 which extends throughout its length in which the cable to be supported is received. It will be appreciated that the layers of wires used to form the cylinder could have other cross sections, but the arrangements shown are the preferred ones. Further, the layers can each have their wires arrangement helically, the wires then being given alternate left-hand and right-hand lays. This results in the tube thus produced being a torsionally-balanced strand. When the tubular member is used to support and contain an optical fibre package, which may contain one or more optical fibres, the fibre or fibres may be so arranged as to be slack. That is the fibres are each somewhat longer than the tubular member to ensure that they are not subjected to any strain. The outer-layer may be surrounded by one or more layers of water-resistant material, if desired. Claims

1. A pressure-resistant load-carrying tubular member, for use for supporting a communication cable, which includes at least one stranded layer formed of adjacently-arranged wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported.

2. A pressure-resistant load-carrying tubular member, for use for supporting a communication cable such as an optical fibre package, which includes at least one stranded layer formed of alternately-arranged round-section and waistedsection wires stranded together to form a substantially complete hollow tubular member, the internal cross-section of the tubular member being such as to accommodate the cable to be supported.

3. A member as claimed in claim 1 or 2, and which has at least two layers of stranded wires.

4. A member as claimed in claim 3, and in which adjacent layers of stranded wires have their wires arranged helically with opposite lays.

5. A pressure-resistant loadcarrying tubular member, for use for supporting a communication cable, substantially as described with reference to the accompanying drawing.

New Claims or Amendments to Claims filed on 21 May1981 Superseded ClaimsNew Claims:

6. A pressure-resistant load-carrying member for use for supporting an optical fibre cable package, which member includes two stranded layers each formed of alternately-arranged roundsection and waisted-section trapezoidal wires stranded together to form a complete hollow tubular member, in which the round-section wires in the two layers are staggered with respect to each other, and in which the internal crosssection of the inner one of said two tubular members is such as to accommodate the optical fibre cable package to be supported.

7. A member as claimed in claim 6, and in which adjacent layers of said stranded wires have their wires arranged helically with opposite lays.

8. A submarine optical fibre cable which includes a pressure-resistant load-carrying member as claimed in any one of claims 1 to 7, and an optical fibre cable package inside the hollow layer or the innermost hollow layer.