Abstract: To enable sequential fusion splicing of the optical fibers of two lengths of optical fiber ribbon, the fusion splicer has, on each side of the fusion station, means for arranging the exposed end portions of the optical fibers of each ribbon, over a limited length between the position at which they are lightly clamped and the cut back end of the ribbon, to follow a curved path whose centers of curvature lie on a line extending transversely of the ribbon. Preferably, one of these means is an externally screw threaded rod which extends under and transversely of the optical fibers of one of the ribbons and in the grooves of which the optical fibers are arranged to lie. By unscrewing the rod, each lightly clamped optical fiber in turn drops from the rod and straightens so that its end to be fusion spliced protrudes beyond the ends of the other optical fibers of the ribbon. Fusion splicing of the pair of aligned optical fibers is then effected.

Abstract: An edge connector (1) comprises a housing (2) having an aperture (3) in which an edge (6) of a circuit board (7) is received. One or more connector pins (12) (13) extending from the housing each have a sharp-edged contact region (19), plated with a ductile metallic material such as tin or lead, and capable of penetrating and deforming a similarly plated contact pad (20) to establish a low resistance electrical connection therebetween. The housing (2) and the circuit board (7) are pivotable with respect to one another between a first position in which there is clearance between the connector pins (12) (13) and the contact pads (20) present on the circuit board, and a second position in which they are in electrical contact one with the other. Securing means such as resilient clips (25) (26) (30) (34) hold the circuit board with respect to the housing (2) in the second position.

Abstract: Cable is wound on to a spool (2) comprising a longitudinally extending barrel (3) and a flange (4) extending from the barrel at one end thereof. At an ejection station the spool (2) is separated from the wound cable to leave a coil of cable (1). A removable flange (5), of a larger diameter than the spool flange (4), is placed over the barrel of the spool prior to winding. Subsequent removal of the spool (2) leaves a coil of cable (1) resting on the flange (5). An ejection station for separating the spool (12) from the wound cable is also described.

Abstract: An electric cable joint (including a termination) comprises at least one inner component heat-shrunk onto a cable or on to at least one part of a cable and at least one outer component of resilient material which is an interference fit with the inner component(s). The heat-shrink component takes up considerable variation in the size of the underlying cable (or part thereof) so that a range of cable sizes can be accommodated by a much smaller number of inner component sizes than in a purely "slip-on" range.

Abstract: A non-metallic flexible elongate strengthening member suitable for use as a strengthening member of an optical cable comprises a plurality of non-metallic flexible elements helically laid around a central non-metallic flexible element, each of which flexible elements comprises a multiplicity of filaments of non-metallic reinforcing material, e.g. non-optical glass or an aromatic polyamide, bonded together by a heat-softenable organic material, e.g. polypropylene or nylon, and is coated with a release agent, e.g. a film of silicone oil. The flexible elements of the assembly are so deformed and compacted together that any tendency for the flexible elements to spring apart is substantially eliminated.

Abstract: A gelled oil filling compound primarily intended for optical cables which meets the standard drainage test at 70.degree. C. and is stable to prolonged exposure at -40.degree. C. consists essentially of a low aromatic hydrocarbon oil and a block copolymer with a molecular weight in the range 200,000 to 2,000,000. The block copolymer comprises at least one segment tending to confer solubility in the oil and at least one segment tending to inhabit it, the preferred example being the polymer sold under the trade mark KRATON G1651 which has a center segment which is a random copolymer of ethylene and butylene and two end segments consisting essentially of styrene units.

Abstract: Apparatus for winding cable on to a spool comprises a movable table (11) on which at least three spools may be located. The table is mounted substantially horizontally such that the spools may be located thereon with their longitudinal axes substantially vertically upright. The table is movable between three positions; a loading position (12) where an empty spool is loaded on to the table; a winding position (13) where a spool is rotated and cable (2) is wound on to the spool; and an unloading position (14) where a wound spool is removed from the table. There is also provided first lifting means (15) for loading a spool on to the table, second lifting means (16) for removing a spool from the table, means (30) for loading the cable on to a spool, means (38) for cutting the cable, and a programmable controller adapted to control the sequence of operations.

Abstract: An overhead electric conductor comprises a central tubular metal core, at least one layer of helically wound bare metal wires surrounding the core and, loosely housed in the bore of the core, at least one optical fibre element. The optical fibre element comprises a flexible tube of elongate transverse cross-section in which is loosely housed an optical fibre ribbon structure and which is resiliently set in such a form that it follows a path of smoothly curved undulations, the axes of curvature of which lie parallel to one another and normal to the axis of the tube.

Abstract: Apparatus for locally abstracting light from the core of a buffer coated optical fibre, especially a buffer coated single mode optical fibre, suitable for use when monitoring the fusion splicing of optical fibres comprises a body of perspex having at least three faces, an arcuate contact face adapted to bear against a smoothly curved length of buffer coated optical fibre, an exit face through which light entering the body through the contact face can emerge and a reflecting face which will reflect light entering the body through the contact face in a direction towards the exit face. Light emerging from the smoothly curved length of buffer coated optical fibre and passing through the contact face into the body will be directed and reflected towards the exit face from where it can pass into a light detector.

Abstract: Apparatus for injecting light into the core of a buffer coated optical fibre, especially a buffer coated single mode optical fibre, suitable for use when monitoring fusion splicing of optical fibres comprises a body of perspex having at least three faces, an arcuate contact face adapted to bear against a smoothly curved length of buffer coated optical fibre, an entry face through which light emitted by a light source is injected into the body in a direction towards the contact face, and a reflecting face which reflects injected light in a direction towards the contact face. Light injected through the entry face is directed and reflected towards the smoothly curved contact face from where it will pass through the buffer coating and cladding of an optical fibre against which the body bears into the core of the optical fibre. The body is inexpensive and operates efficiently with an inexpensive light emitting source.

Abstract: A pressure regulating device for fluidtight, fluid-filled apparatus comprises a solid body with a shallow recess in a surface enclosed by a flexible diaphragm. A narrow passage, preferably of capillary dimensions, connects the recess to the interior of the apparatus and the diaphragm is flexible enough to be deformed without injury so as to enter the recess and reduce its volume substantially and preferably practically to zero. The recess contains a volume of air which for optimum performance should be equal to the amount by which the volume can be reduced by movement of the diaphragm and also equal to the volume expansion of the fluid (or if more than one device is fitted its share of the fluid) from atmospheric conditions to mean working temperature (less the volume of any air occluded elsewhere in the apparatus). By this means, the diaphragm is substantially unstressed both under atmospheric conditions and under mean working conditions, since the gas will be compressed to a negligible volume.

Abstract: In an optical fibre element comprising a flexible tube in which optical fibres are loosely housed, the tube is resiliently set in such a form that it follows a longitudinally extending path which, between any two longitudinally spaced positions, is greater in length than the rectilinear distance between the two positions. Preferably, the tube is resiliently set to follow a path of smoothly curved undulations, the axes of curvature of which lie parallel to one another and normal to the axis of the tube. When the resiliently set tube is subjected to a longitudinally applied tensile force, the tube will tend to straighten against the action of its resilient set, thereby to reduce the tensile force applied to the optical fibres.

Abstract: An enclosure for housing sub-racks carrying circuit boards and modules carrying other electricalcomponents comprises two separately formed identical bodies, each of which constitutes an end wall and a part of each of a pair of oppositely disposed side walls and which are secured together to form an enclosure having two oppositely disposed open faces. Adjacent one of the open faces of the enclosure, means is provided on which sub-racks and modules can be detachably mounted in the enclosure either with the front faces of the sub-racks and modules flush with the open face of the enclosure or with the faces of the sub-racks and modules set back from the open face. Preferably, inner parts of the end walls of the bodies adjacent the other open face of the enclosure are so shaped that sub-racks and modules can be trapped in the enclosure between the inner parts of the end walls when the enclosure is assembled.

Abstract: A simple and inexpensive optical fibre joint comprises an elongate core consisting of an assembly of rods defining between their adjacent radially outer surfaces a plurality of interstices; an elastomeric sleeve tightly surrounding the core; and two optical fibres aligned in one of the interstices with their neighboring end faces abutting or closely spaced apart. The depth of the interstice and the degree of expansion of the elastomeric sleeve having regard to the diameters of the aligned optical fibres are such that the optical fibres are tightly held in the interstice. The rods constituting the elongate core may be of rigid material or of an elastomeric material.

Abstract: In an overhead electric traction system a simple and inexpensive mid-point anchor comprises a mast and, mounted on the upper part of the mast, a cantilever structure comprising a pair of rigid elongate members which lie in a common plane and extended transversely with respect to and lie spaced apart in a direction lengthwise of the track, and which at their ends nearer the track are connected to the mast by a third transversely extending elongate member inclined at an acute angle to the common plane. The ends of the members remote from the track are connected to opposite ends of a rigid bar which extends lengthwise of the track, which is pivotally connected to the mast about a vertical axis and which, at each of its end portions, is connected to the mast by a flexible tie. In the event of an unbalanced load on the catenary, pivotal movement of the cantilever structure about the vertical axis is prevented by one of the flexible ties and the out of balance load is transferred to the mast as a torsional load.

Abstract: An optical fibre element suitable for loosely housing in a bore of an optical cable comprises a plastics tape having transversely spaced on and secured to one of its major surfaces two plastics insulated electric conductors extending lengthwise of the tape and a second plastics tape overlying and secured to the plastics insulated conductors to form between the pair of plastics insulated conductors an elongate compartment. Loosely housed in the elongate compartment is an optical fibre ribbon comprising a plurality of optical fibres arranged side by side and embedded in an elongate plastics body. Each conductor may be of a resilient metal and/or each plastics tape may be of a resilient plastics material and each conductor and/plastics tape may be resiliently set in such a form that the optical fibre element follows a path of smoothly curved undulations whose axes of curvature lie transverse to the longitudinal axis of the element.

Abstract: An optical fibre ribbon structure suitable for loosely housing in a bore of an optical cable comprises an optical fibre ribbon which comprises a plurality of optical fibres arranged side by side and embedded in a plastics body and which extends lengthwise on and is secured to one surface of a plastics tape and two plastics insulated conductors, one of which insulated conductors extends lengthwise on and is secured to the surface of the tape on one side of the optical fibre ribbon and one of which insulated conductors extends lengthwise on and is secured to the surface of the tape on the other side of the optical fibre ribbon. Each insulated conductor has an overall diameter substantially greater than the overall thickness of the optical fibre ribbon.

Abstract: A honing tool for sharpening an end of an electrode to be employed in the fusion splicing of optical fibres includes a rotatably mounted honing wheel of frusto-conical shape and a rotatably mounted bush whose axis is parallel to that of the honing wheel and is so coupled to the honing wheel that, when the honing wheel is rotated with respect to the body of the tool, the bush will be rotatably driven in the same rotational direction. An electrode is so mounted coaxially within the bush that an end of the electrode will bear against the frusto-conical surface of the honing wheel and that, when the honing wheel is rotated, rotation of the electrode with respect to the bush is prohibited and the abrasive frusto-conical surface of the honing wheel will form a sharp point at the end of the electrode.

Abstract: A station for testing one or more electric conductors (8) covered in insulating material (9) includes one or more contact probes (14) movable to pierce the insulation and contact the conductors (8). Additionally one or more contact pins (12), resiliently mounted in a mounting (11) are movable to engage and electrically connect with one free end of the exposed conductors (8). A voltage set up between the contact probes (14) and the one or more contact pins (12) provides an indication of whether the contact probes have made an electrical connection with their respective conductor. The probes (14) are circular with a circumferential cutting edge (15). They may conveniently be moved to pierce the insulating material (9) by rotation of their mounting (16) about the axis of the conductor under the action of a cam follower (17) on a cam profile (18).

Abstract: An improved coil package comprises a closable carton formed from a folded blank of cardboard and having a pair of oppositely disposed major side walls, each of which has an aperture in axial alignment with the aperture of the other major side wall and, removably housed in the carton, a reel on which is carried a coil of wire. The flanges of the reel have apertures of diameters less than the apertures in the major side walls of the carton and end parts of a rigid hollow hub formed of a transversely folded metal strip protrude from the reel flanges and are so rolled radially outwardly that their extreme edges bite into the outer faces of the reel flanges, no portions of the rolled over end parts of the hub protruding beyond the planes containing the outer faces of the major side walls.