GB694862A - Improvements in or relating to electric cables - Google Patents

Abstract

694,862. Drawing. JOHNSON & PHILLIPS, Ltd., and HOLLINGSWORTH, P. M. Aug. 31, 1951 [June 2, 1950], No. 13844/50. Class 83 (iv). [Also in Group XXXVI] A metal-sheathed cable is made by providing a tube, which is to become the cable sheath, at the control end 2 of a track 1, inserting an armature attached to a core tow-line in the forward end of the tube, pulling the tube along the track while generating an electromagnetic field to retain the armature stationary, thus drawing the tow-line into the tube, pulling a cable core from the control end through the tube by means of the tow-line until the forward end of the core extends beyond the forward end of the tube, then drawing the rear end of the tube, with the rear end of the core therein, back through reducing means at the control end to reduce the tube to fit the core, the drawing of the tube along the track and the drawing of the core into the tube, both being effected by drawing-in means at the control end. A hawser 4 lying along the track 1 passes over sheave 5 to capstan 6 at the control end 2. The core towline 12, having an armature 28 at one end, passes along track 1 over sheave 13 to capstan 14. The tube 20 is drawn from drum 21 by means of hawser 4, to which it is secured by connector 22 of the type described in Specification 627,815, through a magnet field element 23, clamp 24, swaging machine 25 in its inoperative position, and straightening device 26 of the type described in Specification 627,815. When the forward end of the tube is in element 23 the armature 28 is placed therein and the element 23 energized, so that as the tube is drawn forward to the position shown the tow-line 12 enters the tube. When the rear end of the tube is in the swaging device 25 it is halted and secured by clamp 24. The cable core 27 is drawn from drum 29 and connected to a wire 28a attached to the armature 28, the element 23 being de-energized. The capstan 14 is operated to draw the tow-line 12 and core 27 through the tube 20, until the forward end of the core is outside the tube 20 and the rear end is flush with the rear end of the tube. The swaging device 25, which may be of the type described in Specification 647,185, is operated to reduce the end of the tube 20 to grip the core 27, and, after releasing clamp 24, the reduced end is drawn through a sinking die 30, round draw drum 32 to cable drum 33, the hawser 4 and tow line 12 being drawn back to the starting position. The element 23 is re-energized, and as the armature 28 enters the field an indication is given, any excess length of the tube 20 is cut off and the core 27 disconnected from the armature 28.