Patent GB-817321-A (GB)
Title: Improvements relating to transmission systems
Inventor: FORMBY JOHN ALBERT
IPC: H02P5/49
Filed: 1954-08-27
Abstract: 817,321. Electric selective signalling systems. FORMBY & CO. Ltd., J. Aug. 25, 1955 [Aug. 27, 1954], No. 24973/54. Class 40 (1). A transmission system for imparting motion to a rotary output member comprises a step-type electric motor operative to rotate in response to a sequence of pulses and adapted to execute a sequence of steps in exact numerical correlation with the said sequence of pulses which are derived from a set of pulse-generating means spaced non-uniformly on a medium or member arranged to be moved with uniform speed, whereby the said output member is caused to execute a mode of motion determined by the relative spacing of the pulse generating means on the said uniformly moved medium or member. In the arrangement shown a rotary disc 1 has pins 1a, which are not equally spaced circumferentially, coacting with an amplifier 3, modulator 4 and oscillator 5 to pass pulses over a line L to a detector 6, and via shaping amplifier 7 to a dekatron 8 in which the discharge is stepped along the cathodes operatively connected by resistors 10 to the grids of twelve thyratron type tubes 9a ... 9l forming a distributer arrangement for the sequential combined energizations of the windings 16a, 16e, 16i of an M-type motor 16. The anode circuits of the tubes 9a ... 9l are interconnected by capacitors 12, the corresponding connections being between the tubes 9a, and 9g, 9b and 9h ... 9f and 9l, and a tube rendered conducting cuts off its associated tube. A different distribution of currents is applied to the three windings 16a, 16e, 16i of the motor 16 for each step of the dekatron 8 in response to the sequence of twelve pulses. If, for example, it is assumed that with the reception of the twelfth pulse of the series the tube 9l and also the tubes 9g ... 9k are conducting, with the tubes 9a ... 9f non-conducting, the arrival of the first pulse of the next sequence will make valve 9a conductive and the tube 9g will be cut off. As a result, with tubes 9a, 9b in opposite conditions and contact members 13 engaging opposite contacts, the winding 16a receives no current or is " dead," winding 16e has a negative current and the winding 16i a positive current. The next, or second, impulse of the series will render the tube 9b conducting so that winding 16a receives positive current and windings 16e, 16i, negative and positive current respectively. On the arrival of the third impulse 9c becomes conducting so that the tube 9i is cut off, and winding 16i is " dead," whilst windings 16a, 16e have positive and negative currents respectively, The fourth pulse renders tube 9d conducting so that tube 9j is cut off and with tube 9i already cut off, the winding 16i receives a negative current whilst the windings 16a, 16e receive positive and negative current respectively. For the fifth and. sixth impulses which makes tubes 9e, 9f conducting in sequence so that the tubes 9k, 9l are correspondingly cut off, the currents in the windings 16a, 16i are unchanged, whilst in sequence the winding 16e becomes " dead " and then has a positive current. The irregular pulses fed to the dekatron 8 may be generated by a disc with apertures irregularly spaced in the circumferential direction, in combination with a. light source and a photo-electric cell or photoelectric multiplier, Fig. 2 (not shown), or as in Fig. 3 (not shown), the control medium may be a tape provided with magnetic spots spaced at irregular but predetermined intervals and fed past a pick-up head connected to an amplifier leading to a modulator 4 or transmitter oscillator 5, as in Fig. I.