Abstract: A length of filament, such as wire or optical fiber, is loosely coiled on a flat carrier, in the form of a figure of eight coil, the lobes of which are laid respectively in clockwise and anticlockwise directions, by feeding the filament downwards through a gimbal mounted guide member attached to reciprocating means whereby the guide member is oscillated about two horizontal axes at right angles, corresponding to the transverse and longitudinal axes of the figure of eight coil produced. The guide member preferably incorporates a compressed air injection gun, to assist in maintaining the downward travel of the filament at a desired constant speed, the relationship between the filament travel speed and the oscillation frequencies being controlled to produce a figure of eight coil of a desired size.

Abstract: In an optical fibre cable having a core of one or more straight optical fibre waveguides, with or without a textile sleeve, the protective sheat surrounding the core consists of a plastic tube incorporating reinforcing tensile material in its wall, the relative proximity of the fibres, the sleeve if present, and the sheath being such as to permit freedom of movement of the fibres in relation to the sheath, in both radial and axial directions. The preferred form of reinforcement consists of elongate tensile members, such as steel wires, embedded in the sheath wall, equally spaced apart and lying parallel to the core. The reinforced sheath is formed by a single continuous extrusion step, the reinforcing members being fed into the extruded plastic material simultaneously with the feeding of the cable core into the bore of the extruded sheath.