GB1424672A - Wire strand - Google Patents

Abstract

1424672 Stranding GKN SOMERSET WIRE Ltd 17 May 1973 [25 April 1972] 19046/72 Heading D1T The invention is concerned with strands made from sector shaped wires 10, Fig. 4, by advancing the wires through a lay plate 18, Fig. 1, to a closing die 20. According to the invention each aperture in the lay plate 18 has a cross-section matching that of a wire 10, and the lay plate 18 is rotated relatively to the closing die 20 to twist and torsionally stress the wires 10 beyond their elastic limit. The twisting is such as to cause the helix angle to be greater than is required in the final product. The strand is then wound under tension onto a reel 29 which is rotated about its own axis 30 and about a second axis 34 aligned with the advancing strand, the rotation about the second axis 34 being such as to remove the elastic torsional stresses and provide a strand of the required helix angle. The apparatus shown in Fig. 1 includes killing rolls 27 arranged to bend and reverse bend the strand to reduce residual stresses; and a power driven capstan 28. Strand traversing means 36, 37 moves the strand back and forth across the reel 29. Each wire 10 has an ultimate tensile strength of at least 90 tons per square inch and its three apices are rounded. Each strand is of medium or high carbon steel. Fig. 3 shows a modified strand comprising a core wire 9 and one outer layer of wires 10, there being, when the strand is unstressed, a circumferential spacing between adjacent wires 10. The fill factor of the strand is at least 85%. As shown in Fig. 2 the lay plate 18 has tungsten carbide guides 21, each formed with a hole 22 corresponding to the cross-section of a wire 10. The centre of the curved edge 23 of each hole 22 is about 5‹ in anti-clockwise direction about the central axis of plate 18 back from the 12 o'clock position. The guides 21 may be angularly adjustable to vary their settings to values other than said 5‹.