Abstract: Apparatus for measuring the length of a moving elongate element (1), such as a cable, comprises first and second rotative members (2), (3), rotatable by frictional contact with the element. The second member (3) responds to changes in the velocity of the element (1) to a differing extent to that of the first member (2). The rotation of each member is measured by detectors (11), (12), and data fed to a microprocessor (13) which compares the rotation of the two members to give an indication of the amount of slippage between one or both members and the element (1). The slippage is taken into account in determining the length of the moving element. The differing response to changes in velocity can be achieved by the second member (3) being of a different inertia to that of the first member (2). Alternatively the members frictionally contact the element to a different extent.

Abstract: An electric conductor suitable for use in an overhead electrical and optical transmission system comprises a layer or layers of helically wound wires, at least one elongate compartment within and extending throughout the length of the conductor and, loosely housed in the elongate compartment, at least one optical fibre ribbon structure comprising a plurality of optical fibres and flexible elongate reinforcing elements of resilient material arranged side by side and embedded in an elongate body of plastics material, each resilient reinforcing element being set in such a form that the ribbon structure follows a path of smoothly curved undulations whose axes of curvature lie parallel to one another and normal to the longitudinal axis of the ribbon structure.

Abstract: An optical fibre ribbon structure suitable for use in an optical cable or other application where there is a risk that optical fibres will be subjected to a tensile force comprises a plurality of optical fibres and flexible reinforcing elements of resilient material arranged side by side and embedded in an elongate plastics body. Each resilient reinforcing element is set in such a form that the ribbon structure follows a path of smoothly curved undulations whose axes of curvature lie parallel to one another and normal to the longitudinal axis of the ribbon structure. When the undulting ribbon stucture is subjected to a tensile force, the ribbon structure straightens in a lengthwise direction against the action of the resilient reinforcing elements thereby reducing the tensile force otherwise applied to the optical fibres. When the tensile force is removed, the ribbon structure returns towards its original undulating form.

Abstract: In an overhead electric traction system for railways, a simple and inexpensive cantilever structural assembly includes a pole (1) comprising a lower part (3), an upper part (4) which is separately formed with respect to and is mounted on the lower part and to which a cantilever structure (21) is attached and, inter-connected between the upper end of the lower part and the lower end of the upper part, a tubular insulator (3) of plastics insulating material. The insulator (3) will withstand any normal mechanical loading to which the pole (1) will be subjected while it is in service and is of such a shape as to provide the necessary minimum creepage path between neighboring ends of the lower part (3) and upper part (4) of the pole.

Abstract: A signal generator which can inject an optical signal into all the fibers of a cable, and so be left unmanned during jointing operations, uses a tungsten-halogen or other incandescent light source. This is collimated by conventional optical elements and pulsed by a mechanical chopper. All the fiber ends are aligned with and positioned within the chopped collimated beam.

Abstract: A hand tool for providing an optical fibre with an end face which is flat and lies in a plane radial to the fibre axis comprises four elongate members extending side by side. The first member is of tubular form and surrounds the other three members and has, mounted near one of its ends, jaws of two pairs of jaws transversely spaced on opposite sides of the longitudinal axis of the member and, between the jaws, a table having a curved surface. The second member is pivotally connected to the first member at its end remote from the table about an axis extending transversely of the members, is urged away from an internal surface of the first member by a leaf spring and carries, near its other end, the other jaws of the transversely spaced pairs of jaws. The jaws of one pair of jaws are mounted to exert a tensile force on the fibre.

Abstract: A low-tack, non-cell-filling filling medium for telecommunication cables comprises 70-98% liquid base, 1-15% of a block copolymer and 1-15% of a dispersed phase former. The base may consist of a hydrocarbon or hydrocarbon mixture whose molecules are substantially incapable of diffusing into polyethylene, polypropylene or (with or without wax) other cellular insulating material at temperatures of up to 80.degree. C. or it may be a mixture of a mineral oil with a hydrocarbon or hydrocarbons satisfying the foregoing condition and also being soluble in the oil and having a low enough (number average) molecular weight to reduce significantly the osmotic pressure of the medium. The block copolymer includes at least one block tending to confer solubility in the base and at least one block tending to inhibit such solubility, so as to have a strong tendency to form a gel with the base.

Abstract: A composite connector for use with a circuit board is formed from a folded sheet metal preform and has, at one end, a socket in which a terminal pin of a circuit component can be resiliently gripped and, at the other end, a tubular end portion including two bifurcated contacts for displacing the insulating covering of an insulated wire when it is introduced between their limbs. The longitudinally extending free edges of the folded preform in the socket are circumferentially spaced with respect to the longitudinally extending free edges of the folded preform in the tubular end portion. Integral resilient tongues in the socket for effecting electrical contact with a terminal pin of a circuit component are circumferentially spaced with respect to the slots bounded by the limbs of the bifurcated contacts.

Abstract: In an overhead electric traction system, an overhead contact wire is enclosed throughout its length within an elongate protective cover of resilient electrically insulating material. The cover is secured to the contact wire, is symmetrical about a longitudinally extending vertical plane passing through the axis of the contact wire and includes a pair of transversely extending base walls which underlie and are spaced from the contact wire and abut in the vertical plane. When engaged by a transversely extending elongate current collector carried by a travelling vehicle, the base walls are deflected upwardly and outwardly away from one another to expose the running surface of the contact wire and permit the current collector to effect electrical contact with and collect current from the contact wire; after passage of the current collector, the base walls return to their original undeflected positions so that the contact wire is again enclosed within the cover.

Abstract: In a method of continuously casting unrefined electrodes in quantity for use in the electrolytic refining of metal in which a metal e.g. copper, strip is continuously cast and cut at spaced positions along its length to form electrodes, a substantial saving in metal is effected by casting the strip in such a way that, in longitudinally spaced minor portions of its length, the strip has at least one hole, recess in at least one of its side edges, or region of substantially reduced thickness as compared with that of the major portion of its length.

Abstract: In a bandoleer of composite insulation displacement connectors, the tubular end portion of each composite connector incorporating diametrically opposed bifurcated insulation displacement contacts is joined to a side edge of a metal strip by a fracturable link so folded out of the plane of the strip that the common axis of the slots of the bifurcated contacts lies at an acute angle to the longitudinal axis of the strip. This acute angle is such that, when composite connectors are fitted into adjacent holes in a circuit board, the positions of the bifurcated contacts of each composite connector are such that a length of insulated conductor introduced between the limbs of the bifurcated contacts of the composite connector will extend between neighboring composite connectors with negligible risk of rendering difficult connection of a length of insulated conductor to a neighboring composite connector.

Abstract: Conform machinery for continuous friction-effected extrusion having a wheel comprising two cheek members, a central hub which forms the base of the working passageway and two separate ring members which form the side walls of the working passageway and provide slip surfaces between the cheek members and the rings. The abutting slip surfaces of the cheek members and rings are shaped to allow thermal expansion of the rings relative to the cheek members with the slip surfaces in driving engagement but to limit radial movement in a radial direction at any particular place on the circumference to a distance less than the relative expansion in the diameter of the ring between ambient temperatures and the expected working conditions of the machine.

Abstract: A separable electric connector for use "downhole" in the oil industry or else where when large pressure changes are encountered comprises a socket part which, prior to the assembly of the part, can be filled with a viscous insulating fluid. The corresponding plug part has a tubular member which is closed at one end and surrounds the socket part with a clearance when the connector is assembled. A male member which forms or carries contacts is upstanding from the closed end of the tubular member to enter the socket part and make the required contact or contacts. A passage is provided to allow flow of the fluid from the socket member into the space within the tubular member. A sleeve member subsequently enters the tubular member, whereupon the fluid flows mainly between the sleeve member and the tubular member until a seal is formed, for instance by a sealing ring. An escape path is formed, as between the socket member and the sleeve member, to allow the subsequent escape of excess fluid.

Abstract: In the manufacture of an optical cable element comprising a tube of plastics material loosely housing at least one optical fibre, a water-impermeable medium in a liquid or semi-liquid state is applied to an advancing optical fibre immediately upstream of an extruder in such a way and under such a pressure that the advancing optical fibre with water-impermeable medium therearound passes into the extruder. After a tube of polymeric material has been extruded around the advancing optical fibre and the surrounding water-impermeable medium in such a way that the internal diameter of the tube is greater than the overall diameter of the optical fibre and the extruded tube has been drawn down and so treated that the molecules are longitudinally oriented, the space in the tube not occupied by the optical fibre is filled with water-impermeable medium of a jelly-like nature.

Abstract: Waterproof filling medium, used in telecommunication cables with cellular insulation of polyethylene or polypropylene, is based on a mineral oil (with or without a gelling agent such as microcrystalline wax) and includes two non-polar additives. The first is soluble and of low enough molecular weight to reduce significantly the osmotic pressure of the base, but does not diffuse into the insulation below 80.degree. C.; and the second is polymeric and of high enough molecular weight to increase the resistance to flow to obtain the required non-draining property. Filling of cells in the insulation is inhibited.

Abstract: A method of making insulated wires or cables in which a tube of crystallizable polymeric material is first extruded over size on the wire, cooled until it can be gripped and then reheated and stretched to produce crystalline orientation and to collapse it into contact with the wire is distinguished by first holding the tube at a temperature between its glass transition temperature and its crystalline melting point long enough for the degree of crystallinity to be significantly increased. Physical properties after orientation are considerably improved.

Abstract: In a simple optical fibre duplex coupler of high light-coupling efficiency, two elongate optical guides are so arranged that, over a part of their lengths extending from one end of the coupler, one optical guide surrounds and is coaxial with the other optical guide with their neighboring end faces lying in a substantially common plane. At a position intermediate the ends of the coupler, the optical guides separate into distinct optical channels. The optical guides are surrounded by and enclosed in a body 1 of a transparent plastics material having a refractive index less than that of the outer optical guide. Preferably, the inner optical guide is a composite optical fibre and the outer optical guide is an elongate body of moulded transparent plastics material having a refractive index greater than that of the material of the cladding of the composite optical fibre.

Abstract: In a cable gland comprising two tubular members each wider at one end than at the other and telescopically engageable at their respective wider ends to define an annular chamber around a cable end inserted through the telescoped members with means for urging the tubular members axially together after the chamber has been filled with an appropriate sealing compound, at least one resilient contact finger is in electrical continuity with one of the tubular members and projects inwardly in order to make effective contact with a corrugated sheath or other metallic layer of the cable. The contact finger(s) is/are thus effectively embedded in the sealing compound, and locked in position when it sets, so giving a secure contact as well as an effective fluid-tight seal.

Abstract: In a continuous friction-actuated process for the extrusion of copper, a passageway 3 is formed between an arcuate first member and a second member in the form of a wheel 1 having a circumferential groove 2 formed in its peripheral surface into which groove the first member projects. The wheel is rotated and metal is fed into the passageway at one end and extrudes from the passageway through at least one die orifice 6 located in or adjacent to an abutment member 5 extending across the passageway at the other end thereof. The abutment member is of substantially smaller cross-section than the passageway so as to leave a substantial gap between the abutment member and the groove.

Abstract: A flexible stranded body, such as an electric conductor of an overhead electric transmission or distribution system, comprises at least one stranded layer of elongate elements of metal or metal alloy, at least one elongate compartment within and extending throughout the length of the stranded body and, loosely housed in the elongate compartment, at least one separate optical fibre and/or at least one optical bundle. Preferably, the elongate compartment extends within a circumferentially rigid central core which is surrounded by the stranded layer or layers but it may be a bore in an elongate element of a stranded layer or an elongate space bounded by two adjacent elongate elements.The questions raised in reexamination request No. 90/000,772, filed Apr. 16, 1985, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).