Patent GB-410167-A (GB)
Title: Improvements in or relating to road traffic control systems
IPC: G08G1/082
Filed: 1932-11-10
Abstract: 410,167. Road signals for controlling traffic. SIEMENS & GENERAL ELECTRIC RAILWAY SIGNAL CO., Ltd., Caxton House, Tothill Street, and EDWARDS, F. A., 82, Elliscombe Road, Charlton, both in London. Nov. 10, 1932, No. 31762. [Class 118 (ii).] In a traffic control system of the progressive type, when the right-of-way is about to be given to a main road at one intersection, a static timer is set in operation to cause, after a predetermined delay, a relay at a succeeding intersection to initiate the transfer of the right-ofway to the main road, the delay being determined by the rate of charge or discharge of a condenser. In the embodiment in which the signals are time-controlled the duration of the cycles at the various intersections, and the predetermined delay referred to above can be varied from a central point by altering the pulsing rate of an impulser which controls the discharge times of the various sub-station timing condensers. The application of the invention to a road-pad controlled system is also described. Fixed time cycle operation of master controller. With the apparatus in the condition shewn the A or main road has right-of-way and the red signals are shewn to road B. The relay 1R operates and charged condenser Q1 discharges through Y8. When the voltage across G has dropped sufficiently T operates followed by TA and CB pulls up altering the signals to Amber on road A and Amber-Red on road B. Condenser Q1 charges fully over Y2 and condenser Q2 starts discharging through Y4 to time the Amber period. Relays T and TA release and relay LC energizes and locks. When lamp C flashes, relays AT and ATA pull up so that relay CB releases and the signals change to Red on road A and Green on road B. The condenser Ql now begins to discharge for a second time to time the right-ofway period and eventually G again flashes, and T and TA pull up, operating CA and releasing slow relay LC. The signals change to Amber- Red on road A and Amber on road B and Q2 starts discharging over Y3. After the amber time period C flashes, AT and ATA pull up, CA releases and the apparatus returns to the position shewn in the drawing. Progressive arrangements. At each of the crossings connected with the main road A is a subsidiary controller of which one only is shewn in the figure. The timing circuits operate in a manner similar to that described above except for the relay FP. Relay FP is operated when CA at the master controller has pulled up to take the right-of-way from the cross roads. When FP energizes, Q1 commences to discharge and eventually the right-of-way is taken from the cross road and given to the main road, a lag is thus created between the master and subsidiary controllers and this lag is adjusted to enable a vehicle travelling at a predetermined speed to pass along the main road without stopping. Further subsidiary controllers are provided at further crossings, the relays FP in these controllers being controlled either by the master controller or by a back contact of the CA relay at the preceding crossing. Varying time of cycle. To vary the time of the cycle at all crossings and the lag between the various controllers the impulser shewn is provided. When the condenser Q3 has discharged, S flashes and R pulls up. Relay R is energized and holds up whilst Q4 discharges through it, closing during its operated period a charging circuit for Q3. When 1R falls away, Q3 again begins to discharge through Y6 and Q4 again charges and the cycle is repeated. As the discharging circuits of condensers Q1 of the red and green timers are closed only during the energized periods of 1R, it follows that by altering the cycle of the impulser, the time of the cycles at the crossings and the lay between the stations can be varied. Pad-operated system. The invention is also described as applied to a vehicle-actuated system, for example, of the type described in Specification 408,706, the arrangements being such that when a vehicle passes along a main road, a signal is sent forward to each crossing to initiate transfers of the right-of-way to the main road, if held by the cross road, so long as the cross road has already had the right-of-way for a predetermined minimum time. The Provisional Specification states that a threeelectrode thermionic valve may be used in place of the neon tubes, the operation being controlled by the potential applied to the grid of the valve.