Patent GB-1390641-A (GB)
Title: Methods and apparatus for manufacturing a transmission medium having an inner conductor and an outer tubular conductor
IPC: H01B13/016
Filed: 1972-03-29
Abstract: 1390641 Making electric cables; bonding metal; drawing WESTERN ELECTRIC CO Inc 29 March 1972 [31 March 1971] 14625/72 Headings B3A B3E and B3P [Also in Divisions H1 and B5] In the manufacture of a coaxial conductor 50 having an outer conductor/shield formed as a laminate of conductive materials (e.g. copper and steel), having different coefficients of thermal expansion and joined by a temperature sensitive adhesive, the laminate has a predetermined three dimensional curvature imparted to it with the material at a predetermined elevated temperature and the adhesive in a flowable state and the laminate is then cooled while removing the curvature to relieve stress in the laminate. The outer conductor, of the coaxial conductor is thus stress free and the impedance of the conductor remains constant with time. General layout, Figs. 1 and 2.-Copper tape 69, steel tape 71 and an intermediate strip 60 of adhesive polymer drawn from supply positions are fed to an aligning and laminating apparatus 74. Simultaneously, wire to form the central conductor for a supply 76 is drawn down in apparatus 78 and then fed to a device 80 where insulating discs 54 are applied to it. The laminate, having been corrugated by a device 81 is then associated with the central conductor and insulating discs to be fed to a tube forming and soldering station 82. The finished cable is drawn through the apparatus by a capstan 84 and is wound up at 86. Laminating device, Figs. 3 and 5.-Copper strip 69, steel strip 71 and adhesive polymer strip 60 are passed to an aligning device 90 and are then passed through three pairs 74 of heated presser rolls for bonding. Each roller pair comprises a fixed, driven lower roller 116 and an upper roller 114 which is mounted in vertically movable bearings subjected to the pressure of air piston-cylinder devices 122 the air pressure in pistons 122 being adjustable. Each roller has internal cavities 124 in which cartridge heaters 130 has placed, connection to the heaters being made through slip rings 134, 136. Gears 142, 144 drivingly connect the rollers to ensure identical speed of each roller. After leaving the last roller pair and while it is still at a temperature such that the plastics adhesive is flowable the laminate is passed over a roller 146 having a surface which is of spherical section. After leaving roller 146 the laminate cools and passes about a roller 147 in flat, stress relieved form. Wire drawing machine. Fig. 9.-An ultrasonically vibrated wire drawing die 156 is mounted in a tank 148 of cleaning and lubricating fluid, e.g. trichlorotrifluoroethane and copper wire is drawn through the die by a tapered capstan 152 also immersed in the cleaning fluid. Application of insulating discs.-After drawing inner conductor 52 passes through insulating disc forming and applying device 80 in which horseshoe shaped discs 54 are punched from tapes 164, 166, e.g. of polyethylene, and applied to the conductor. Conductor 52 passes centrally through the device 80 and through the centre of a die plate 178 which lies at right angles to the path of the conductor. Plate 178 has in its upper surface grooves 168, 170 through which tapes 164, 166 are indexed. Dies 182, 184, 186, 188 are arranged in the grooves and pass through the plate to open into lower grooves 222, 224, 226, 228 which have a cross-section just sufficient to receive a disc 54. Punches on supports 349 punch, in sequence, discs from the tapes and press them into grooves 222, 224, 226, 228 where they are moved by sliding applicators 252, 254, 256, 258 and applied to conductor 52. The punch supports 349 have cam followers 360 which are operated. by a rotating barrel cam 364. Supports 349 also carry lower cam portion 356 which pass snugly through holes 292, 294, 296 298 in sliding applicators 252, 254, 256, 258 to impart the required reciprocation for disc applying. Corrugating device, Fig. 15.-The laminate after cooling is fed to corrugation rollers 390, 391 via an input tension control roller 400 which is movable with varying tension in the laminate. This movement actuates a resistor and as a result the speed of the last roller in the laminating apparatus 74 is adjusted. On leaving the corrugating rollers the laminate is passed about a movable roller 394 which moves in response to varying tension in the laminate and adjusts a potentiometer 396 through a belt and pulley arrangement. The motor 388 driving the corrugating rollers is then adjusted to correct the tension in the corrugated laminate. Tube forming and soldering, Figs. 20, 21, 22.- The inner conductor with insulating discs and the corrugated outer laminate is then brought together at apparatus 82 where they are passed together through a series of rollers 506, 508 which form the laminate about the central conductor and insulating discs. The cable is then passed to a soldering station to seal the outer conductor/shield. Shaft 460 of roller 506 is driven and carries a gear 484 which drives via planet gears 494, 490 a gear 486 on shaft 472 of top roller 508. Planet gear 494 is mounted on links on shaft 460 and planet gear 490 is similarly mounted on shaft 472. Links 504 hold the shafts 492, 502 of the planet gears at constant spacing. This driving arrangement enables the top rollers 508 to be vertically adjusted by calibrated screw devices 478 without interrupting drive between the rollers. In addition a link 496 on shafts 460, 502 engages portions of the casing to limit the movement of the planet gear arrangement, i.e. between the positions of Figs. 21 and 22. This arrangement also enables the two rollers to run at different speeds for a short period which is stated to eliminate unwanted friction effects on the laminate.