Patent GB-1182128-A (GB)
Title: Method of and Apparatus for Stranding Flexible Materials
Inventor: HARVEY PETER
IPC: H01B13/02
Filed: 1967-06-30
Abstract: 1,182,128. Stranding wires &c. BRITISH INSULATED CALLENDER'S CABLES Ltd. 28 June, 1968 [30 June, 1967], No. 30338/67. Heading D1T. A cable comprising portions of reversed direction of lay is made by feeding a group of wires 1 into a variable capacity accumulator 4 which rotates unidirectionally about the axis of the wires and twists them in one direction. The strand 11 thus formed is withdrawn from the accumulator 4 in the same direction as the wires were fed into it whereby the strand 11 is twisted in the opposite direction to the originally applied twist. The instantaneous relationship between the linear speeds at which the wires enter and leave the accumulator 4 is varied so that the length of strand in the accumulator is varied and a reversing lay is applied to the strand. In Fig. 1 the speed at which the strand leaves the accumulator 4 is varied by a programmed or manually controlled capstan 7. The take up speed of reel 19 is varied in accordance with the output of capstan 7. In Fig. 2 (Figs. 2-9 not shown) the strand leaving speed is varied by passing the strand around two pulleys (or groups thereof) and varying the distance between the pulleys. In Fig. 3 the input speed of the wires is varied by passing them between a varying speed belt and pulley device. In this embodiment the speed of the strand leaving the accumulator remains constant. In Fig. 4 the input speed of the wires is varied by a varying speed capstan (34), and, optionally, varying capacity accumulators (36 and 37) are used to keep the speed and tension of supply of the wires to the capstan (34) constant. In Fig. 5 the strand speed is varied by two intercoupled variable capacity accumulators (38 and 39) inserted in the path of the strand, one before the twisting accumulator 4 and one after the twisting accumulator 4. In Fig. 6 the strand is withdrawn at a varying speed from a first twisting accumulator (44) and fed into a second twisting accumulator which rotates in a direction opposite to the first. The strand is withdrawn from the second twisting accumulator with a modified twist and is wound up. The twisting accumulator(s) are preferably bucket-shaped with the inner surface impart tapering toward the strand inlet, the part near the strand outlet being of uniform diameter. The bucket may, however, be of uniform diameter or tapered from end-to-end. The inner surface can be lubricated with a water spray, see Fig. 7. The bucket can be fitted with photoelectric detectors to give an indication of the amount of strand therein. This detected amount of strand or an amount of strand calculated revolution counters can be used to vary the strand speed, see Fig. 8. The strand speed varying capstan can be driven by a hydraulic motor driven by a variable capacity swash plate pump, see Fig. 9. In an alternative arrangement the twisting accumulator can be formed by two moving pulleys, or groups thereof, which move towards and away from each other. The wires can be fed to the twisting accumulators direct from extruders or via haul-off capstans. The wires may be pretwisted before entering the twisting accumulators. A lapping head or adhesive applicator to hold the twisted strand in position may be provided. The strands can be metallic or non- metallic and may be a cellular polytheneinsulated telephone cable.