Patent GB-338917-A (GB)
Title: Improvements in or relating to traffic control signals
IPC: G08G1/085
Filed: 1929-08-28
Abstract: 338,917. Automatic Telephone Manufacturing Co., Ltd., Paulett, W. H., Rice, T. G., and Williams, M. O. Aug. 28, 1929. Road signals.-In an arrangement for effecting the operation of traffic control signals at predetermined intervals, a separate timing device is provided for controlling the change of signal at the end of each interval in the cycle, each timing device being separately adjustable so that the cycle time is represented by the sum of the intervals separately determined by the various timing devices. When the start key K is operated a circuit is completed for charging the condenser c5 by way of the resistance R.5. When the voltage across the condenser is sufficient to strike the neon lamp N5 the relay P is operated and the contact strip p5 shunts the condenser through the resistance r5. When the voltage falls to a certain value, much below that required to strike the lamp, the latter is extinguished, and the relay falls away. Hence by adjusting the resistances R5, r5, the relay may be made to impulse at a convenient speed, say, of 100 per minute. Upon each operation of the relay P, the condenser c1 is connected across the supply mains 10, 11 through the contact strip rc1, resistance R1 and contact strip p1. The tube N1 is struck in 30 seconds during which the relay X will be operated by way of contact strip b5, and the contact strip x1 will complete the circuit of the " stop " lamps SNS of the north and south arms of the crossing, and the " go'' lamps GEW for the east and west cross. The strip a1 completes a locking circuit for the relay A. At the strip a<3> an intermittent charging circuit is completed for the condenser c2, and at the contact strip a4 a point is opened in the circuit of a clear-down relay CO, and at the strip a5 a circuit is completed for the relay Z which, when operated completes the lighting circuit for the " caution " lamps CNSEW. The " caution " lamps and " stop " and " go " signals are shown together for 5 seconds which is the striking time for the lamps N2, whereupon the relay B will be - operated to bring down the relay X to extinguish the " stop " and '' go " signals SNS, GEW and to bring down the relay Z to extinguish the " caution " signals. The relay Y is also operated to complete the lighting circuit for the " stop " and " go " lamps SEW, GNS. These will light for the striking time of the neon lamp N3, say 30 seconds, whereupon the relay C will be operated and will lock up by way of strip c1. An alternative circuit for the relay Z is made and also the charging circuit for the condenser c4. Upon operation of the relay Z, the " caution " lamps are again lighted for 5 seconds, whereupon the neon lamp N4 is struck and the relay D operated, circuits being established so that the " stop " and " go " lamps SNS, GEW are lighted and the other signal lamps extinguished. In addition, the relays A, B, C are unlocked, and the condenser C1 is again charged and the cycle of operations occurs over again. Alternative manual control is provided by a change-over key, the contact strips of which are shown at ik1-ik4, the neon lamp N4 only being used to produce continual flashing of the " caution " lamps. Continued flashing of the red lamps may be arranged for in this case. A remote control key RK, connecting an earthed source of potential to leads 12, 13, is provided to operate a relay RC to cause strips rc1-rc4 to alter the resistances R1-R4 and thus alter the spacing periods of the signals for night traffic. In the case of an alternating current supply, a metal rectifier RAC is used. Two neon lamps only could be used, but the use of four enables a more economical adjustment where the intersecting roads are not of equal importance.