Patent GB-1038071-A (GB)
Title: Traffic light controller
Inventor: LESHER JOHN CLEMENS
IPC: G08G1/07
Filed: 1963-02-05
Abstract: 1,038,071. Road-traffic signalling apparatus. RAD-O-LITE Inc. Feb. 5, 1963, No. 4635/63. Heading G4Q. A traffic controller employs a basic timer giving separate control of red and green phases which is compatible for use with: (a) walk/don't walk equipment; (b) traffic controlled equipment; (c) off-peak flashing; (d) emergency vehicle control. Timer.-Assume initially that relay 8, Fig. 1, and relay 106 are energized lighting the green main street lamps 1 and the red cross street lamps 2, that the mechanically latching relays 44, 67 have their movable contacts 46, 99 and 68, 88 in the position shown, and also that capacitor 54 is discharging through resistors 61, 62, 64. When capacitor 54 becomes discharged valve 56 conducts energizing relay 71. Contacts 74, 75 on this relay make, energizing coil 67 to latch movable contacts 46, 99 and 68, 88 in the other position, and further contacts 72, 73 close recharging capacitor 54 cutting off valve 56 and releasing relay 71. Relay 8 now releases since contacts 43, 46 are open, contacts 7, 9 open but relay 106 remains energized during a time determined by capacitor 118 and resistors 110, 120, 125. During this time the main street amber lights 104 are lit. After the delay time relay 106 releases and the main street red lights 96 are lit over contacts 13, 14. Relay 24 is energized by the changing over of relays 44, 67 lighting the cross street green lights 103 and relay 34 operates preparing the circuit for the cross street amber. Capacitor 54 discharges through resistor 134, 136, 137 until valve 56 switches on. Relay 71 energizes, restoring the movable contacts of the latching relay to the position shown, and recharging capacitor 54 to cut off the valve 56 and release relay 71. Relay 24 now releases connecting the cross street amber lights 133 for a period determined by the time constant of capacitor 141 and resistors 142, 143, 144. Relay 34 releases after this delay period to re-connect the main street green lights 1 restoring the initial conditions. The controller thus provides independent control of the red and green intervals on the main and cross streets and also the amber periods by means of variable resistors 137, 64, 125, 144. Walk/don't walk facilities.-The connection 49 of Fig. 1 is omitted, and the terminals 17, 18, 48, 52, 115, 153 are connected to corresponding terminals of the circuit of Fig. 2. With the switch 192, Fig. 2, in the position shown, when the lights are in the condition with the main street amber 104, and cross street red 2 lit the potential applied to the main street amber light 104 is also applied to valve 157 to cut it off releasing relay 156. This removes the earth from terminal 48 to hold all the traffic lights at red, and also energizes relays 154, 182. When relay 154 operates a " walk " signal 202 is actuated and a negative potential is applied to terminals 153 to hold valve 56 cut off. Once the main street amber light is extinguished capacitor 161 discharges until relay 156 reoperates de-energizing relays 154, 182. Relay 154 releases immediately to energize " don't walk " signal 201, and to remove the bias from valve 56. Relay 182 has a delayed release to allow pedestrians to complete a crossing before restoring the earth to terminal 48. The cycle of the circuit of Fig. 1 then returns to normal until the next time the main street amber light is lit. The walk/don't walk facility may be switched in and out remotely by placing the switch 192 in the off position, and energizing relay 211 via terminal 212. Traffic operation.-The controller may be modified for pad operation by traffic in the cross street by the addition of the circuit of Fig. 3. The controller is normally held with main street green and cross street red, cycling being prevented by the potential from terminal 5 being fed to terminal 153 to hold valve 56 cut off until passage of a vehicle over pad 221 energizes coil 224 of the latching relay to feed a pulse through capacitor 233 to terminal 149 to energize coil 67 in Fig. 1. The controller then starts to cycle changing to main street red and cross street green. When the main street amber lights 104 are lit coil 243 is energized to reset the latching relay contacts, the controller continuing to cycle until the main street green lights are again lit. If the pad 221 is crossed by further cars whilst the cross street green lamps are lit relay coil 223 is energized, and a path is created to incrementally charge capacitors 233, 54 in series prolonging the period timed out by capacitor 54 up to a maximum period when capacitor 233 becomes fully charged. The cycle then proceeds until a main street amber resets the coil 243, whereafter the cycle ceases at the next main street green phase. If the pad 221 is crossed after the expiring of a cross street green phase, when the cross street amber lights 133 are lit then energization of coil 224 does not result in the energization of coil 67 since capacitor 233 is not fully discharged and the controller continues to cycle until a main street amber phase energizes coil 243 to reset the latch, whereafter cycling ceases at the next main street green phase. Off-peak operation.-In order to provide flashing amber lights on the main street and flashing red lights on the cross street during off-peak periods, the jumper 20 is removed from Fig. 1 and the corresponding terminals of the circuit of Fig. 4 connected to those of Fig. 1. Relay 273 is operated either by closing switch 277 or by applying a remote control signal to terminal 274. At the next main street green phase the thermal delay heater 286 is connected to the supply and after the delay period contacts 293, 294 close energizing coil 289 of the latching relay. The contacts of this relay then change over disconnecting heater 286 and energizing relay 308 to disconnect the power supply to Fig. 1 via contacts 318, 322 and connecting the supply to the flasher 329. The output from this flasher is fed via terminals 18, 115 to flash the cross street red lights 2 and main street amber lights 104. When relay 308 is energized a voltage is applied to terminal 342 to provide relay 8 so that when relay 273 is de-energized cycling recommences at a main street green phase. Deenergization of relay 273 energizes coil 298 on the latching relay to reset it, and also relay 308 de-energizes. Emergency control.-To provide an emergency control the jumper 76 is removed, and the circuit of Fig. 5 connected to that of Fig. 1. If it is desired to allow an emergency vehicle to proceed along the cross street a control signal is transmitted which results in receiver 351 providing an output on lead 352 to energize relay 354 which feeds a potential back into the receiver to prevent any further received signals affecting the circuit. Relay 374 is energized connecting the high voltage on terminal 17 to energize relay 67 applying a potential to terminal 126 to set the cross street lights 103 to green to energize a flasher 404, and to energize a relay 383 which connects this flasher to a white light 407 which indicates to a nemergency vehicle that control is obtained. If the controller is already in the cross street green phase relay 67 is not energized and relay 383 is energized immediately. Relay 374 also disconnects the high voltage from timer 53 and the capacitor discharges so that at the end of the emergency period the lights change immediately to the main street green phase. In a similar fashion, the main street may be selected by transmitting a signal which produces an output from the receiver on lead 353 and relays 368, 381, 399, 44 are energized resulting in the main street green phase with the white light 408 on the main street flashing. When the control signal ceases relay 354 (or 368) releases restoring the timer supply to terminal 82a. The relays may include further contacts to disable the other auxiliary circuits.