GB2114771A - Optical cable manufacture - Google Patents

Optical cable manufacture Download PDF

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Publication number
GB2114771A
GB2114771A GB08304093A GB8304093A GB2114771A GB 2114771 A GB2114771 A GB 2114771A GB 08304093 A GB08304093 A GB 08304093A GB 8304093 A GB8304093 A GB 8304093A GB 2114771 A GB2114771 A GB 2114771A
Authority
GB
United Kingdom
Prior art keywords
optical
reinforcing member
grooves
circumferential wall
elongate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08304093A
Other versions
GB8304093D0 (en
GB2114771B (en
Inventor
Edward Zbigniew Kaczmarski
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Balfour Beatty PLC
Original Assignee
BICC PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BICC PLC filed Critical BICC PLC
Priority to GB08304093A priority Critical patent/GB2114771B/en
Publication of GB8304093D0 publication Critical patent/GB8304093D0/en
Publication of GB2114771A publication Critical patent/GB2114771A/en
Application granted granted Critical
Publication of GB2114771B publication Critical patent/GB2114771B/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4479—Manufacturing methods of optical cables
    • G02B6/4489—Manufacturing methods of optical cables of central supporting members of lobe structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/05—Filamentary, e.g. strands
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/06—Rod-shaped
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/15—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
    • B29C48/156—Coating two or more articles simultaneously

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

An optical cable is manufactured by causing a reinforcing member 10 to travel through the extrusion orifice of the extruder (1) and by extruding about the advancing wire a circumferential plastics wall 14 having in its internal surface circumferentially spaced, longitudinally extending grooves. Those parts of the internal surface of the wall 14 between the grooves are bonded to the external surface of the wire 10 so that the grooves are closed by the reinforcing member to form elongate compartments and optical fibres 17 are fed into the grooves as the wall is formed; each optical fibre having such a diameter having regard to the size of its associated groove that it is loosely housed in the elongate compartment. Preferably, the advancing member 10 has an inner metallic core and an outer layer of plastics material. The die 2 forming the grooves in the internal surface of the wall 14 and through which the optical fibres 17 are fed may be oscillated so that the grooves have a continuously reversing lay. <IMAGE>

Description

SPECIFICATION Optical cable manufacture This invention relates to optical cables for the transmission of the ultra-violet, visible and infrared regions of the electromagnetic spectrum, which regions, for convenience, will hereinafter all be included in the generic term "light" and especially, but not exclusively, to optical cables for use in the communications field adapted for transmission of light having a wavelength within the range 0.8 to 2.1 micrometres.
The invention is particularly concerned with an optical cable of the kind comprising an extruded elongate body of rubber or plastics material having embedded therein and extending lengthwise thereof a central flexible elongate reinforcing member and having, extending lengthwise in and arranged in at least one substantially circumferential layer around the longitudinal axis of the body, a plurality of separate elongate compartments in at least one of which is loosely housed at least one separate optical fibre and/or at least one optical bundle as hereinafter defined.
By the expression "optical bundle" is meant a group of optical fibres or a group of fibres including one or more optical fibres and one or more non-optical reinforcing fibres or other reinforcing elongate elements.
It is an object of the present invention to provide an improved method of manufacturing an optical cable of the aforesaid kind, which method is simple and inexpensive and enables the optical cable to be manufactured in a single operation.
According to the invention the improved method comprises causing a flexible elongate reinforcing member to travel in the direction of its length through the extrusion orifice of an extrusion machine; extruding about the advancing reinforcing member a circumferential wall of rubber or plastics material having in its internal surface a plurality of circumferentially spaced, longitudinally extending grooves and causing those parts of the internal surface of the circumferential wall between said grooves to be contiguous with the external surface of the reinforcing member so that the grooves are closed by the external surface of the reinforcing member to form elongate compartments; and feeding into at least one of the grooves in the said circumferential wall as the wall is being formed at least one separate optical fibre and/or at least one optical bundle as hereinbefore defined, the overall diameter of the or each optical fibre and/or optical bundle having regard to the cross-sectional area of the groove into which it is being fed being such that the optical fibre and/or optical bundle is loosely housed in the elongate compartment.
Preferably, at least a circumferential outer part of the flexible elongate reinforcing member is of rubber or plastics material to which those parts of the inernal surface of the circumferential wall between the grooves may be caused to bond to form a monolithic body of rubber or plastics material. Where the rubber or plastics circumferential outer part of the flexible elongate reinforcing member is a separately formed circumferential layer on the reinforcing member, this layer may be extruded on to the reinforcing member upstream of, and in tandem with, extrusion of the circumferential wall.
The reinforcing member may be of metal or metal alloy or of a non-metallic material. In the former case, it may be a plurality of wires stranded together or a single wire; in the latter case, it may be a bundle of carbon fibres or fibres of other suitable material, e.g. non-optical flass fibres or fibres of aromatic polyamide sold under the Trade Mark "Kevlar".
An outer protective sheath of rubber or plastics material may be extruded about the circumferential wall and, if desired, the outer protective sheath may be extruded downstream of, and in tandem with, extrusion of the circumferential wall.
Preferably, the extrusion orifice is defined by an outer die and, surrounded by and co-axial with the outer die, and inner die or point having a throughbore for passage of the reinforcing member and a plurality of circumferentially spaced, longitudinally extending, outwardly projecting ribs which form the longitudinally extending grooves in the circumferential wall and in at least one of which is a bore for passage of a separate optical fibre and/or optical bundle.
The inner die is preferably caused to oscillate about its axis so that each longitudinally extending groove follows a helical path about the longitudinal axis of the reinforcing member, the direction of lay of each groove reversing at spaced positions along the length of the cable.
Alternatively, the inner die may be caused to rotate about the longitudinal axis of the reinforcing member but, in this case, preferably the reels from which optical fibres are fed are mounted at circumferentially spaced positions around an input unit which is rotatably driven about the axis of the advancing cable in the same rotational direction and at the same speed as the inner die (along the lines of a planetary de-torsioning stranding machine head) to compensate for any torque or twist imparted into the optical fibres.
To avoid risk that an optical fibre and/or optical bundle may stick to a boundary surface of a groove, the optical fibre and/or optical bundle may be dusted with a dusting power such as French chalk or talc upstream of extrusion of the circumferential wall.
At least one elongate electric conductor may be fed into at least one of the grooves in the circumferential wall as the wall is being formed, the overall diameter of the or each electric conductor having regard to the cross-sectional area of the groove into which it is being fed being such that the electric conductor is loosely housed in the elongate compartment.
During manufacture of the cable, a waterimpermeable medium of a grease-like nature may be introduced into at least those elongate compartments of the elongate body loosely housing at least one optical fibre and/or optical bundle to fill at least partially those parts of said compartments not occupied by optical fibres and/or optical bundles.
The invention also includes an optical cable made by the improved method hereinbefore described.
The invention is further illustrated by description, by way of example, of the preferred method of and apparatus for manufacturing an optical cable with reference to the accompanying drawings, in which:~ Figure 1 is a sectional side view of the extrusion head of an extrusion machine illustrating extrusion of a circumferential wall of plastics material about an advancing flexible reinforcing member; Figure 2 is the front end view of the inner die of the extrusion head shown in Figure 1 , drawn on an enlarged scale; Figure 3 is a transverse cross-sectional view of the reinforcing member, drawn on an enlarged scale, and Figure 4 is a transverse cross-sectional view of the extruded circumferential plastics wall, drawn on an enlarged scale.
Referring to Figures 1 and 2, the apparatus for manufacturing an optical cable comprises an extrusion machine having an extrusion head in which is an extrusion orifice defined by an outer die 1 and, surrounded by and co-axial with the outer die, an inner die or point 2. The inner die 2 has a throughbore 3 and a plurality of circumferentially spaced, longitudinally extending outwardly projecting ribs 4 in each of which is a bore 6. The inner die 2 is rotatably driven about its axis through gearing 7 and, by periodic reversing of the drive motor (not shown), can be caused to oscillate about its axis.
In using the apparatus shown in Figures 1 and 2 to manufacture an optical cable, a reinforcing member (Figure 3) comprising a single metal wire 1 1 having a circumferentially continuous covering layer 12 of plastics material is drawn through the bore 3 of the inner die 2 as a circumferential wall 14 of plastics material is extruded through the extrusion orifice on to the advancing reinforcing member.The outwardly projecting ribs 4 on the inner die 2 form a plurality of circumferentially spaced longitudinally extending grooves in the internal surface of the circumferential wall 14 and parts 16 of the internal surface of the circumferential wall between the grooves are contiguous with and bond to the plastics covering layer 12 of the reinforcing member 10 to form a monolithic body of plastics material having a plurality of circumferentially spaced, longitudinally extending compartments. Optical fibres 17 are fed through the bores 6 in the inner die into the grooves 1 5, the overall diameter of each optical fibre having regard to the cross-sectional area of the groove into which it is being fed being such that the optical fibre is loosely housed in an elongate compartment. During extrusion of the circumferential wall 14, the inner die 2 is caused to oscillate about its axis so that each longitudinally extending groove 1 5 follows a helical path about the longitudinal axis of the reinforcing member 10, the direction of lay of each groove reversing at spaced positions along the length of the cable.

Claims (16)

1. A method of manufacturing an optical cable which comprises causing a flexible elongate reinforcing member to travel in the direction of its length through the extrusion orifice of an extrusion machine; extruding about the advancing reinforcing member a circumferential wall of rubber or plastics material having in its internal surface a plurality of circumferentially spaced, longitudinally extending grooves and causing those parts of the internal surface of the circumferential wall between the said grooves to be contiguous with the external surface of the reinforcing member so what the grooves are closed by the external surface of the reinforcing member to form elongate compartments; and feeding into at least one of the grooves in the said circumferential wall as the wall is being formed at least one separate optical fibre and/or at least one optical bundle as hereinbefore defined, the overall diameter of the or each optical fibre and/or optical bundle having regard to the cross-sectional area of the groove into which it is being fed being such that the optical fibre and/or optical bundle is loosely housed in the elongate compartment.
2. A method of manufacturing an optical cable which comprises causing a flexible elongate reinforcing member of which at least a circumferential outer part is of rubber or plastics material to travel in the direction of its length through the extrusion orifice of an extrusion machine; extending about the advancing rinforcing member a circumferential wall of rubber or plastics material having in its internal surface a plurality of circumferentially spaced, longitudinally extending grooves and causing those parts of the internal surface of the circumferential wall between said grooves to be contiguous with and to bond to the external surface of the reinforcing member to form a monolithic body of rubber or plastics material having a plurality of circumferentially spaced, longitudinally extending elongate compartments; and feeding into at least one of the grooves in the said circumferential wall as the wall is being formed at least one separate optical fibre and/or at least one optical bundle as hereinbefore defined, the overall diameter of the or each optical fibre and/or optical bundle having regard to the cross-sectional area of the groove into which it is being fed being such that the optical fibre and/or optical bundle is loosely housed in the elongate compartment.
3. A method as claimed in Claim 2, wherein a separately formed circumferential layer of rubber or plastics material is extruded on to the reinforcing member upstream of, and in tandem with, extrusion of the circumferential wall.
4. A method as claimed in any one of the preceding Claims, wherein an outer protective sheath of rubber or plastics material is extruded about the circumferential wall.
5. A method as claimed in Claim 4, wherein the outer protective sheath of rubber of plastics material is extruded downstream of, and in tandem with, extrusion of the circumferential wall.
6. A method as claimed in any one of the preceding Claims, wherein the extrusion orifice is defined by an outer die and, surrounded by and co-axial with the outer die, an inner die or point having a throughbore for passage of the reinforcing member and a plurality of circumferentially spaced, longitudinally extending, outwardly projecting ribs which form the longitudinally extending grooves in the circumferential wall and in at least one of which is bore for passage of a separate optical fibre and/or optical bundle.
7. A method as claimed in Claim 6, wherein the inner die is caused to oscillate about its axis so that each longitudinally extending groove follows a helical path about the longitudinal axis of the reinforcing member, the direction of lay of each groove reversing at spaced positions along the length of the cable.
8. A method as claimed in claim 6, wherein the inner die is caused to rotate about the longitudinal axis of the reinforcing member.
9. A method as claimed in Claim 8, wherein the reels from which optical fibres are fed are mounted at circumferentially spaced positions around an input unit which is rotatably driven about the axis of the advancing cable in the same rotational direction and at the same speed as the inner die to compensate for any torque or twist imparted to each optical fibre.
10. A method as claimed in any one of the preceding Claims, wherein at least one elongate electric conductor is fed into at least one of the grooves in the circumferential wall as the wall is being formed, the overall diameter of the or each electric conductor having regard to the crosssectional area of the groove into which it is being fed being such that the electric conductor is loosely housed in the elongate compartment.
11. A method as claimed in any one of the preceding Claims, wherein a water-impermeable medium of a grease-like nature is introduced into at least the or each elongate compartment of the elongate body loosely housing at least one optical fibre and/or optical bundle to fill at least partially those parts of said compartment not occupied by an optical fibre and/or optical bundle.
12. A method as claimed in any one of the preceding Claims, wherein the or each optical fibre a nd/or optical bundle is dusted with a dusting powder upstream of extrusion of the circumferential wall.
13. A method as claimed in any one of the preceding Claims, wherein the reinforcing member is a plurality of wires stranded together or a single wire.
14. A method as claimed in any one of Claims 1 to 12, wherein the reinforcing member is a bundle of non-metallic reinforcing fibres.
15. A method of manufacturing an optical cable substantially as hereinbefore described with reference to the accompanying drawings.
16. An optical cable made by the method claimed in any one of the preceding Claims.
GB08304093A 1982-02-15 1983-02-15 Optical cable manufacture Expired GB2114771B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08304093A GB2114771B (en) 1982-02-15 1983-02-15 Optical cable manufacture

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8204322 1982-02-15
GB08304093A GB2114771B (en) 1982-02-15 1983-02-15 Optical cable manufacture

Publications (3)

Publication Number Publication Date
GB8304093D0 GB8304093D0 (en) 1983-03-16
GB2114771A true GB2114771A (en) 1983-08-24
GB2114771B GB2114771B (en) 1985-07-31

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Application Number Title Priority Date Filing Date
GB08304093A Expired GB2114771B (en) 1982-02-15 1983-02-15 Optical cable manufacture

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2144559A (en) * 1983-08-05 1985-03-06 Bicc Plc Optical cables
GB2167002A (en) * 1984-11-07 1986-05-21 Telephone Cables Ltd Manufacture of optical cables
EP0248947A2 (en) * 1986-06-13 1987-12-16 Firma Carl Freudenberg Process and apparatus for manufacturing a polymer hose reinforced with threads
US4856266A (en) * 1987-02-10 1989-08-15 Sumitomo Electric Industries, Ltd. Method of producing optical fiber cable
US6189343B1 (en) * 1996-11-13 2001-02-20 Fibre Ottiche Sud F.O.S. S.P.A. Apparatus and method for forming an optical fiber
US7123801B2 (en) * 2004-11-18 2006-10-17 Prysmian Communications Cables And Systems Usa, Llc Optical fiber cable with fiber receiving jacket ducts

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2144559A (en) * 1983-08-05 1985-03-06 Bicc Plc Optical cables
GB2167002A (en) * 1984-11-07 1986-05-21 Telephone Cables Ltd Manufacture of optical cables
EP0248947A2 (en) * 1986-06-13 1987-12-16 Firma Carl Freudenberg Process and apparatus for manufacturing a polymer hose reinforced with threads
EP0248947A3 (en) * 1986-06-13 1988-10-05 Firma Carl Freudenberg Process and apparatus for manufacturing a polymer hose reinforced with threads
US4856266A (en) * 1987-02-10 1989-08-15 Sumitomo Electric Industries, Ltd. Method of producing optical fiber cable
US6189343B1 (en) * 1996-11-13 2001-02-20 Fibre Ottiche Sud F.O.S. S.P.A. Apparatus and method for forming an optical fiber
US6327876B1 (en) * 1996-11-13 2001-12-11 Fibre Ottiche Sud F.O.S. S.P.A. Method for producing a coated optical fiber with reduced polarization mode dispersion
US7123801B2 (en) * 2004-11-18 2006-10-17 Prysmian Communications Cables And Systems Usa, Llc Optical fiber cable with fiber receiving jacket ducts

Also Published As

Publication number Publication date
GB8304093D0 (en) 1983-03-16
GB2114771B (en) 1985-07-31

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PCNP Patent ceased through non-payment of renewal fee