Patent GB-397947-A (GB)
Title: An improved machine for bunching, twisting and covering multi-stranded flexible electric cables
IPC: H01B13/02
Filed: 1932-03-24
Abstract: 397,947. Cables. RIST, D. A. V., Red House, Mettingham, near Bungay, Suffolk. March 24, 1932, No. 8859. [Class 36.] A machine for.making multi-stranded flexible insulated cables comprises a device for twisting a plurality of wires together to form a conductor, a rotary device for applying a covering of yarn insulation to the conductor, means for driving both said devices from a common source of power, and automatic stop means for arresting the machine in the event of interruptions in the supply of any of the wires or of interruption or inadequacy of the yarn covering. In the construction shown in Figs. 1 and 2, the wiretwisting device comprises a horizontal table 2 carrying peripherally arranged spools 3 of wire, the wires 4 of which are drawn upwardly in converging formation to a pulley 6 where the wires are twisted by. rotation of the table 2 which is secured to a vertical shaft 8 driven from the main shaft 16 of the machine through a belt drive 14 in combination with bevel gearing 9, 10. The twisted wires 4, which form a conductor 4a, are led over the pulley 6 and under a jockey pulley 7 and pass through a hollow spindle 28 of a yarn covering device, the covered conductor 4b being then taken through a tube 49 and over a pulley 44 to a capstan 45, whence the covered conductor passes under a pulley 46 and is finally wound on a take-up drum 47. The yarn covering device comprises a table 29 mounted on the upper end of the hollow spindle 28 and above which is supported, on standards 32, a bar 31, the table 29 and bar 31 carrying respectively a vertical tube 29a, Fig. 13, and a guide tube 33 through both of which the conductor 4a passes. A bobbin 30 of yarn is freely rotatable on the tube 29a and the yarn 35 thereof is fed through a bushing 34 in the bar 31 to a notch 33b in the guide tube 33, at which point the yarn is wound on the conductor 4a by rotation of the yarn covering device as a whole. To facilitate removal and replacement of the bobbin 30, the bar 31 and guide tube 33 are slotted laterally so that they may be moved clear of the conductor. Reserve bobbins 30a may he carried on the tube 49. The yarn covering device is rotated by a pulley 36 secured to the hollow spindle 28 and connected by a belt or rope 37 to a pulley 38 on a shaft 39 which is driven bv a chain drive 43 from a vertical shaft 40. The shaft 40, which also turns the capstan 45, is driven by a chain drive 61 from the shaft 8. The means for stopping the machine in event of interruption in the supply of wire from any of the spools 3, comprise a ring 5 of fibre or other insulating material supported from and above the table 2 and through which the wires 4 pass. The wires 4 are fed individually through eyes 18a, Figs. 6 and 7, of feelers 18 which are pivoted at their outer ends 18b to a metal annulus 19 secured on the ring 5. Each feeler is normally held, by its associated wire 4, in the position shown in Fig. 6, but if the wire breaks or the spool from which it is drawn becomes exhausted, the feeler falls into a horizontal position and contacts with a second metal annulus 22 on the ring 5 thereby closing a circuit which operates through a relay to move the main belt drive 14 of the machine on to a loose pulley 12 and to bring the machine quickly to rest by applying a brake 84 to a drum 85 which is mounted on the shaft 8 below the table 2. The means for stopping the machine in the event of inadequacy of the yarn covering comprise a feeler arranged at the mouth of the tube 49, Figs. 2 and 8, immediately above the yarn covering device, the feeler, through which the covered conductor 4b passes, consisting of an eye 52a, Fig. 8, formed at the lower end of a resilient wire 52 secured to a tube 53 which is supported by insulation in the tube 49. An uncovered portion of the conductor reaching the eye 52a completes a circuit connected to the eye and operates, in the manner already described, to bring the machine quickly to rest. In a modified construction the wires 4 are are stranded around a core of untwisted wires, the core being passed to the stranding pulley 6 through a boring in the shaft 8 and table 2.