Abstract: An optical fibre unit having a sheath and a plurality of optical fibre elements loosely housed in the sheath. The sheath is coated with particles of an adherence reducing substance and has a radial thickness that is not substantially greater than 0.3 mm. The coating of adherence reducing particles is applied as a liquid coating. The liquid coating is a dispersion of the particles and heat is applied to evaporate the liquid content of the liquid coating to produce a dry coating of particles on the sheath.

Abstract: The apparatus has a feed mechanism engageable with the optical fibre cable for feeding the cable toward the duct, a mechanism for directing a gaseous flow into the duct for propelling the optical fibre cable along the duct and a drying mechanism disposed upstream of the cable feed device for removing moisture that may be present on an exterior surface of the duct.

Abstract: An optical fibre drop cable for suspension installation includes sheathing having a first portion containing a strengthening arrangement for supporting the cable in a suspension installation and a second portion that is separable from the first portion. The second sheathing portion contains a plurality of electrical conductors. The first sheathing portion defines at least one passage for optical fibers.

Abstract: An aerial cable installation having an aerial cable suspended from a suspension point through a suspension device. This device has a clamp having two saddle members engaging the cable on diametrically opposite sides thereof and a plurality of nut and bolt assemblies extending through aligned holes in flanges of said saddle members for resiliently biasing the saddle members toward each other to clamp against the cable with a selected clamping force. To this end, each nut and bolt assembly includes a helical spring mounted on the bolt thereof between said flanges and the nut of the assembly and the springs are compressed a predetermined amout which is adjustable by tightening or loosening said assemblies.

Abstract: An optical fiber cable for blown installation has a tubular central strength member about which tubes loosely housing optical fibers are stranded. The jacket is preferably formed from a high density polyethylene material and is extruded over the core on which rip cords are positioned. A water blocking compound is provided in each tube in any spaces therein which would otherwise be void. Also a water blocking material is provided between the sheath and the layer defined by the helically wound wrapping tape or binding yam in any spaces between the tubes which would otherwise be void.

Abstract: An apparatus (12) is provided for use in determining a length at least representative of the length of a tube that defines a passage in an optical fibre cable (10) along which an optical fibre unit can be installed by blowing. The apparatus (12) comprises a pressure reservoir (32) in which a gas at a known pressure can be stored, outlet piping (34) connected with the pressure reservoir (32) and having an outlet end spaced from the reservoir for connection to a tube of the optical fibre cable (10). The apparatus has a pressure detecting arrangement (42) for detecting gas pressure in a tube connected with the outlet end of the outlet piping (34).

Abstract: An assembly for use in connecting optical fibers includes a housing (12) for optical fiber joints and a fiber routing device (70) associated with the housing. The housing has a first inlet (41) for receiving optical fibers from a primary side of an optical fiber network and a second inlet (13) for receiving optical fibers from a customer side of an optical fiber network. The fiber routing device (70) has an outlet (78) for feeding fibers from the customer side of the optical fiber network into the second inlet (13) and two inlets (72, 74) for receiving the customer-side optical fibers for feeding to its outlet.

Abstract: An apparatus for and method of installing a cable in ducting from a location intermediate the length of the ducting. The cable is provided in a coil at the location and some cable is passed from one end of the coil into a first portion of the ducting extending from the location to one end of the ducting. The remaining cable is passed from the other end of the coil into a second portion of the ducting extending from the location to the other end of the ducting.

Abstract: The present invention provides an assembly for use in connecting optical fibers. The assembly may comprise a plurality of housings for housing connections between optical fibers and a guide arrangement for guiding optical fibres into the housings. The guide arrangement may comprise a plurality of guide devices each having one inlet port for the passage of optical fibres into the guide arrangement and one outlet port for guiding optical fibers into the housing. The guide arrangement may also include one further inlet port for receiving optical fibres from another guide device and one further outlet port for guiding optical fibres to another guide device.

Abstract: A take up apparatus 10 for drawn optical fiber comprises: a take-up stand 22 supporting a first, storage bobbin 12 about a first axis 20; a motor 32 for rotating this first bobbin about that axis; a supporting means 36 supporting a second, sampler bobbin 14 about a second, different axis 34; a second motor 38 for rotating this second bobbin about the second axis; and means for controlling the relative rates of rotation provided by the motors. In use drawn fiber is guided about the first bobbin to the second bobbin and the bobbins are rotated to wind the fiber about the first bobbin and onto the second bobbin during initial drawing of the fiber. Subsequently the fiber between the bobbins is cut and the drawn fiber is wound onto the first bobbin.

Abstract: In a method of manufacturing an optical fiber cable comprising optical fiber units 12 disposed within an extruded sheath 14 with water absorbent powder 16 being provided between the optical fiber unit or units and the sheath, the fiber units pass through an extruder cross-head 36 extruding said sheath 14 together with a tape 22 transporting the water absorbent powder 16. The tape is formed upstream of said extruder crosshead 36 into a channel into which said water absorbent powder is delivered and the tape is adhered to the inside surface 24 of said sheath 14 by fusion thereto.

Abstract: An assembly 10 for use in connecting optical fibers comprising a plurality of housings 12 for housing optical fibre connections. Each housing is pivotally mounted with respect to an associated rigid routing member 14 which has passages for routing fibers to the housing via respective flexible conduit means which extend between the routing member and the housing. Adjacent routing members 14 are push-fittable together such that the housings 12 are in an aligned bank when in stowed positions. Each housing 12 is pivotable from its stowed position out of alignment with the other housings for access.

Abstract: An assembly for use adjacent an earthed suspension region 20 of an all-dielectric self-supporting cable 10 suspended in an electric field at the earthed suspension region from a tower or the like for limiting dry band arcing adjacent the earthed suspension region is disclosed. The assembly includes an electrically conductive device 21 clamped to the cable remote from the earthed suspension region 20 and structure defining a current path having an arc gap connected between the device 21 and the earthed region 20.

Abstract: A device 22 for use adjacent an earthed suspension region 20 of an all-dielectric self-supporting cable 10 suspended in an electric field at the region 20 from a tower or the like for limiting dry band arcing adjacent the region 20 is disclosed. The device includes members 34, 36 for defining a sleeve 26 for fitting to the cable adjacent this region 20 and elements 38, 40, 42, 44 for defining two closures 28, 30 for the sleeve. These closures are engageable with the cable at longitudinally spaced apart locations for forming with the cable and sleeve a closed zone 32 between the closures. Use of the device maintains the outer surface of the cable dry over a portion 24 thereof adjacent the region 20 which would otherwise be susceptible to dry band arcing.

Abstract: In order to install an optical fiber cable 110 in a duct 112 a plurality of vents 130, 132, 134 spaced apart along the duct are operated such that during blowing any vent 130 upstream of the leading end 138 of the cable is closed and when there is at least one vent 132, 134 downstream of the cable leading end at least the downstream vent 132 closest to the cable leading end is open for venting gas from the duct. In this way the pressure decay and pressure gradient profiles are modified during installation to improve installation performance.

Abstract: An assembly comprising a self supporting aerial cable and tension clamp means including gripping means for gripping the cable, the gripping means comprising at least one helically wound rod fitted over the cable's outer sheath, wherein ##EQU1## where C is the outer diameter of the cable, R is the diameter of the or each rod and W.sub.R is the outer diameter of the unstressed winding of the or each rod.

Abstract: The tension in an optical fiber being drawn from a preform is monitored by sensing its motion transverse to the drawing direction and analysing the sensed motion using an autoregressive time-series model to provide a power spectrum. One of the peaks of the spectrum is identified as associated with the fundamental natural frequency of the drawn fiber and the frequency of that peak is used in a calculation of the tension of the fiber.

Abstract: Apparatus for use in applying particles to an external layer of uncured resin material of a coating of an optical fibre unit with at least one optical fibre, said apparatus including means (50) defining an axially extending through-passage (52) through which, in use, such an optical fibre unit is passed, said passage defining means having an inlet (62) for admitting fluidized particles into said through-passage, and said through-passage being provided with means (64) for generating turbulence in such fluidized particles in said through-passage.

Abstract: An assembly 10 for use in connecting optical fibers to an optical fiber device having input and output tails includes a plurality of housings 12 for housing optical fiber connections and a housing 18 for housing at least one passive optical device. The tails of the one or more devices are routed through manifold 16 to the housings 12 via respective routing members 14 and the optical fibers to be connected to the tails are routed to the appropriate housings 12 via these routing members 14. The housings 12 are arranged in an aligned bank adjacent the manifold 16 and each housing 12 is moveable out of such alignment for providing access thereto.

Abstract: An assembly 10 for use in connecting optical fibers to an optical fiber device having input and output tails comprises a plurality of housings 12 for housing optical fiber connections. Each housing 12 is typically mounted to, and supported by a respective routeing member 14. The routeing members are rigidly connected one to another such that the housings are arranged in an aligned bank. Each housing is pivotable for providing access thereto from the stowed position out of alignment with the other housings.