US3605084A - Apparatus for digital control of traffic control timers - Google Patents

Apparatus for digital control of traffic control timers Download PDF

Info

Publication number
US3605084A
US3605084A US863309A US3605084DA US3605084A US 3605084 A US3605084 A US 3605084A US 863309 A US863309 A US 863309A US 3605084D A US3605084D A US 3605084DA US 3605084 A US3605084 A US 3605084A
Authority
US
United States
Prior art keywords
gating circuit
output terminal
output
traffic
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US863309A
Other languages
English (en)
Inventor
John Matysek
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
REMOTE CONTROLS CORP
Original Assignee
REMOTE CONTROLS CORP
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by REMOTE CONTROLS CORP filed Critical REMOTE CONTROLS CORP
Application granted granted Critical
Publication of US3605084A publication Critical patent/US3605084A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/28—Modifications for introducing a time delay before switching
    • H03K17/292—Modifications for introducing a time delay before switching in thyristor, unijunction transistor or programmable unijunction transistor switches
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/07—Controlling traffic signals
    • G08G1/081—Plural intersections under common control
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/07—Controlling traffic signals
    • G08G1/085—Controlling traffic signals using a free-running cyclic timer

Definitions

  • ABSTRACT A traffic control system utilizing digital timing signals, which can be derived from locally available 60 hertz power, to time each traffic interval.
  • the timing signals are transformed to pulses marking the initiation of each traffic interval. These in turn are converted into signals which can be transmitted, for example via two pair of electrical conductors, from a remote traffic guidance center to a local traffic controller in which they are reconverted to signals for each trafi'ic phase. These phase signals are then steered to switching circuits which control energization of the traffic signal indicators.
  • the timing circuit can be utilized independently as a cyclic timer, either with or without conversion for transmission to a remote location.
  • the present invention pertains to a trafiic guidance and control system and to a cyclic timer found within that system. More particularly, the present invention pertains to a system for operation of right-of-way signal indicators at traffic intersections either independently of central control or under the command of a computer which for example might be within a remote traffic guidance center. In another aspect, the present invention pertains to a cyclic timer for generating functions to control cyclic operations.
  • the flow of traffic in heavily traveled areas is generally guided and controlled at least in part by means of signal indicators such as the well-known red-yellow-green signal lamps which divide the right-of-way between the various conflicting traffic phases at the intersection in accordance with some predetermined sequence.
  • signal indicators such as the well-known red-yellow-green signal lamps which divide the right-of-way between the various conflicting traffic phases at the intersection in accordance with some predetermined sequence.
  • the frequency of numerous consecutive major intersections on one main roadway may require such traffic guidance indicators at each such intersection.
  • the indicators at consecutive intersections sequentially provide right-of-way on the main roadway so that a car travelling on that roadway will continuously receive the right-of-way and thus can travel from one end of the roadway to the other through the several intersections without having to stop.
  • the direction of heaviest traffic flow determines the direction in which right-of-way is sequentially provided, and this is liable to be different at different times of day, during morning and evening rush hours, for example.
  • the present invention is a traffic guidance and control system utilizing digital timing signals derived, for example from locally available 60 hertz power to time each trafiic interval.
  • the timing signals are transformed to signals which can be transmitted, for example via two pair of electrical lines, from a remote center to a local traffic guide which in turn converts these signals into the necessary commands for the energization of the traffic signal indicators.
  • Two pairs of conductors can accommodate up to seven commands, and if needed additional commands can readily be handled with additional conductors on a binary basis.
  • the commands can be transmitted over a single wire or via a radio channel on a multiplex basis or by means of a modulation technique such as frequency modulation multiplexing.
  • FIG. 1 is a block diagram representation of a traffic guidance and control system in accordance with the present invention
  • FIG. 2 is a block diagram of a timing circuit suitable for use in the traffic guidance system of FIG. 1;
  • FIG. 3 is a block diagram of a function-to-line converter suitable for use in the traffic guidance system of FIG. I;
  • FIG. 4 is a schematic diagram of an encoder suitable for use in the function-to-line converter of FIG. 3;
  • FIG. 5 is a block diagram of a line-to-function converter suitable for use in the traffic guidance system of FIG. I;
  • FIG. 6 is a schematic diagram of the line-to-function converter of FIG. 5.
  • 60 hertz excitation from a suitable source is applied via line 10 to clock 12 which provides the necessary timing signals for operation of the traffic guidance system of the present invention.
  • clock 12 which provides the necessary timing signals for operation of the traffic guidance system of the present invention.
  • These timing signals are applied by clock 12 to function-to-line converter 14 which generates the necessary traffic guidance signals from them.
  • Clock 12 and function-to-line converter 14 might be within a remote central traffic guidance center, or they might be located at the intersection to be controlled. If at a remote location, the outputs from function-to-line converter 14 are applied by means such as via cable 16 to line-to-function converter 18 which in turn applies the desired excitation to the signal lamps within traffic signal 20.
  • Cable 16 might be any suitable cable such as an existing telephone cable having the necessary wires available.
  • cable 16 can be a single conductor having the several outputs from function-to-line converter 14 multiplexed thereon, or in place of cable 16 a radio link can be utilized.
  • Traffic signal 20 might be any suitable device such as the well-known red-yellow-green traffic light device.
  • FIG. 2 depicts a suitable digital clock in which 60 hertz excitation on line 10 is applied to a shaping and dividing circuit 30 which provides a one-pulse-per-second signal on line 32. This onepulse-per-second signal is applied to dividing circuit 34 which provides ten Output signals, one in turn at one second intervals on each of the ten output lines 36 from circuit 34.
  • dividing circuit 34 provides ten Output signals, one in turn at one second intervals on each of the ten output lines 36 from circuit 34.
  • each output line 36 from dividing circuit 34 is energized in turn, and the energized output line changes with each pulse on line 32.
  • These outputs from circuit 34 thus represent one second intervals from an arbitrary time zero to a time nine seconds after time zero.
  • the nine output line from dividing circuit 34 is connected as an input to dividing circuit 38 which can be identical to circuit 34.
  • Circuit 38 thus provides 10 output signals, one in turn at 10 second intervals on each of 10 output lines 40, and the energized output line 40 changes with each pulse on the nine output line 36 from dividing circuit 34.
  • the outputs from circuit 38 thus represent ten second intervals from time zero to seconds after time zero.
  • the nine output line 40 from dividing circuit 38 is connected as an input to dividing circuit 42 which likewise can be identical with dividing circuits 34 and 38.
  • Circuit 42 provides hundreds output time signals in turn at 100 second intervals on its 10 output lines 44, with the energized output line 44 changing with each pulse on the nine output line 40 from dividing circuit 38.
  • the 10 output lines 36 from dividing circuit 34 are connected respectively to the 10 positions of switch 50 within function-to-line converter 14, as depicted in FIG. 3. Likewise, these 10 output lines from circuit 34 are connected to the respective switch positions of lO-position switches 52, 54, and 56.
  • the 10 output lines 40 from dividing circuit 38 are connected respectively to the 10 positions of switches 58, 60, 62, and 64, and the 10 output lines 44 from dividing circuit 42 are connected respectively to the 10 positions of switches 66, 68, 70, and 72.
  • AND gate 74 has its three inputs tied to the movable contacts of switches 50, 58, and 66; while AND gate 76 has its three inputs tied to the movable contacts of switches 52, 60, and 68, AND gate 78 has its three inputs tied to the movable contacts of switches 54, 62, and 70, and AND gate 80 has its three inputs tied to the movable contacts of switches 56, 64, and 72.
  • AND gate 74 provides an output indication to indicate the initiation of the traffic phase A right-of-way interval, designated the A-green or AG-interval.
  • AND gate 76 provides an output indication to initiate the traffic phase-A clearance interval, designated the A-yellow or AY-interval
  • AND gate 78 provides an output indication to initiate the B- green or BG-interval
  • AND gate 80 provides an indication to initiate the B-yellow or BY-interval.
  • Switches 50-72 are set to indicate the time after time zero at which their respective interval is to be initiated, with switches 50-56 indicating the units, switches 58-64 the tens, and switches 66-72 the hundreds of seconds after time zero at which the intervals are to commence. In the representative example of FIG.
  • switches 50, 58 and 66 are each set to the position, and so at time zero when clock 12 provides outputs on the zero output lines of dividing circuits 34, 38, and 42, each of the three inputs of AND gate 74 is energized so that gate 74 provides an output signal to initiate the AG interval.
  • switches 52, 60, and 68 are set to the time at which the AY interval is to be initiated; switches 54, 62, and 70 are set to the time at which the BG interval is to be initiated; and switches 56, 64, and 72 are set to the time at which the BY interval is to be initiated.
  • Clock 12 can be reset in any of several manners, and as illustratively depicted in FIG.
  • an additional set of IO-position switches 51, 53, and 55 are connected respectively to the i0 outputs of dividing circuits 34, 38, and 42, and have their moving contacts connected as inputs to AND gate 57.
  • the output of gate 57 is applied via line 59 to clock 12 to reset the clock to time zero, for example by resetting each dividing circuit 34, 38, and 42.
  • function-to-line converter 14 is located at a remote traffic guidance center, then the outputs of AND gates 74, 76, 78, and 80 can be connected via lines 82, 84, 86, and 88, respectively, to encoder 90 which encodes the four functions AG, AY, BG, and BY to signals for transmission for example over three lines 92, 94, and 96 within cable 16 to the line-to-function converter 18 located at the intersection.
  • Cable 16 for example, might be two pair of lines within an existing telephone cable, with the fourth line 98 utilized to provide a common reference or ground for the system.
  • Circuitry suitable for use as encoder is shown in detail in FIG. 4 and includes four identical encoding circuits 1020, 1102b, 1182c, and 102d. Since these circuits are identical, only the circuitry of phase A green-encoding circuit 102a is shown in detail.
  • Each component within AG encoding circuit 102a bears a reference numeral ending in the letter suffix a, and en coding circuits 102b, 1020, and 102d, for AY-encoding, BG- encoding, and BY-encoding, respectively, include like components which are herein referred to by like reference numbers but having the letter suffix of the encoding circuit 102b, 1020, or 102d in which they are found.
  • NPN-transistor 104a has its base coupled through resistor 106a to the cathodes of diodes 108a, 109a, and 110a, the anodes of which are tied to input terminals 112a, 113a, and 114a respectively.
  • the base of transistor 104a is also coupled to ground through resistor 116a.
  • Transistor 1104a has its emitter tied to ground and its collector coupled by resistor 118a to power terminal 120a which is connected to a suitable source of positive potential such as a source of +22 volts DC.
  • the collector of transistor 1040 is also connected to the base of NPN-transistor 122a, the collector of which is tied to power terminal 1120a.
  • the emitter of transistor 122a is tied to the anode of silicon controlled rectifier (SCR) 124a which has its cathode coupled to ground through resistor 126a.
  • SCR silicon controlled rectifier
  • the gate of SCR 124a is coupled through resistor 128a to the cathode of diode 130a which has its anode tied to input terminal 132a.
  • the gate of SCR 124a is also coupled through resistor 1340 to its cathode.
  • the cathode of SCR 124a is tied to output terminal 1360 from the AG-encoding unit 102a.
  • Encoding units 102b-l02d contain identical circuitry.
  • the four encoding circuits 10211-10211 are interconnected to cyclically provide output indications as the traffic guidance system cycles through its operation.
  • Line 82 applies the AG- pulse from AND gate 74 to input terminal 132a of unit 1020.
  • line 84 applies the AY-pulse from AND gate 76 to input terminal l32b of unit 102b
  • line 86 applies the BG-pulse from AND gate 78 to input terminal 1320 of unit 1026
  • line 88 applies the BY-pulse from AND gate 80 to input terminal 132d of unit 102d.
  • Unit 102a has its output terminal 136a connected to input terminals 114C and 114d of units 1020 and 102d, respectively.
  • Unit l02b has its output terminal 136b connected to input terminals 114a and 112d of units 102a and 102d, respectively.
  • Unit l02c has its output terminal 1136c connected to input terminals 112a and ll4b of units 102a and 102b, respectively.
  • Unit llOZd has its output terminal 136d connected to input terminals 11212 and 112C of units 10217 and 1026, respectively.
  • Output terminal 1360 is coupled through diode 138 to output line 92 from encoder 90.
  • output terminal 136b is coupled through diode 140 to output line 94;
  • output terminal 1360 is coupled through diodes 142 and 144 to output lines 92 and 96 respectively; and output terminal 136d is coupled through diodes 146 and 148 to output lines 94 and 96 respectively.
  • the four functions AG, AY, BG, and BY are encoded by encoder 90 to signals which can be transmitted via the three lines 92, 94, and 96. While only the four functions AG, AY, BG, and BY are illustrated, up to seven functions can be encoded on the three lines 92, 94, and 96 (plus a condition in which voltage is present on none of the three lines). By adding more lines additional functions can, of course, be encoded.
  • each of the transistors 104a-104d is cut off and each of the transistors l22a-l22d is conducting.
  • Each of the SCRs l24a-l24d is off, but current is available through the corresponding transistors l22a-ll22d to the anodes of the SCRs.
  • clock 12 enables one of the AND gates to apply a pulse on its output line, that pulse initiates operation of the corresponding encoding circuit 102.
  • AND gate 74 applies the AG-pulse on line 82 through input terminal 132a, diode 130a, and resistor 128a to the gate of SCR 124a, that SCR commences to conduct.
  • the AY-pulse on line 84 turns on SCR 124b.
  • Current from that SCR passes through output terminal 136b, input terminal 114a, diode 110a and resistor 106a to turn on transistor 1040.
  • the current from SCR 124b also retains transistor 104d in its conductive state, thereby continuing the blockage of current from SCR 124d. This insures that SCR 124d can not be turned on by extraneous pulses or other noise to give erroneous output indications.
  • the current from SCR 124b also passes through diode 140 to output line 94 from encoder 90.
  • the BG-pulse on line 86 from AND gate 78 activates encoding unit 1021: and deactivates unit 102b, while holding unit 102a in its inactive condition.
  • Unit 1020 energizes output lines 92 and 96 from encoder 90.
  • the BY-pulse on line 88 from AND gate 80 activates encoding unit 102d, deactivates unit 1020, and holds unit 1021; inactive, while energizing output lines 94 and 96 from encoder 90.
  • the four input functions AG, AY, BG, and BY are encoded into a three-line set of signals for transmission via cable 16.
  • the signals on lines 92, 94, and 96 are applied as inputs to decoder 160 which converts them back to the four functions AG, AY, BG, and BY. These four functions are applied via lines 162, 164, 166, and 168, respectively, to function steering logic 170 which separates the signals into the necessary excitations for the trafiic lamps within traffic signal 20.
  • Function steering logic 170 thus provides an output indication to the phase-A green switch 172 when the phase-A green lamp is to be energized, an output indication to the phase-B red switch 174 when the phase-B red lamp is to be energized, an output indication to the phase-A yellow switch 176 when the phase-A yellow lamp is to be energized, an output indication to the phase-B green switch 178 when the phase-B green lamp is to be energized, an output indication to the phase-A red switch 180 when the phase-A red lamp is to be energized, and an output indication to the phase-B yellow switch 182 when the phase-B yellow lamp is to be energized.
  • These switches in turn are connected to the corresponding indicator lamps within traffic signal 20.
  • Line-to-function converter 18 also receives ground line 98 which is within cable 16, thereby insuring a common voltage reference.
  • FIG. 6 depicts the detailed circuitry of line-to-function converter 18.
  • Each of the lines 92, 94, and 96 entering decoder 160 from encoder 90 activates a gate control circuit.
  • line 92 is connected to the anode of diode 202, the cathode of which is coupled through resistor 204 to the base of NPN- transistor 206.
  • Transistor 206 has its collector coupled through resistor 208 to a source of positive voltage, its emitter tied to ground, and its base coupled to ground through resistor 210.
  • Serially connected resistors 212 and 214 are coupled between the collector of transistor 206 and ground, and the junction of resistors 212 and 214 is tied to the base of NPN- transistor 216.
  • Transistor 216 has its collector coupled through resistor 218 to the positive voltage source and its emitter tied to ground.
  • Lines 94 and 96 are connected to identical gate control circuits which are shown in FIG. 6 having components bearing reference numbers identical to those associated with the corresponding components in the gate control circuit associated with line 92 but including the suffix letter a in the gate control circuit associated with line 94 and the suffix letter I; in the gate control circuit associated with line 96. Thus, these latter two gate control circuits are not described in detail.
  • Each trafiic phase has a three-input gate 219 associated with it to decode the signals on lines 92, 94, and 96.
  • diode 220 has its cathode tied to the collector of transistor 216
  • diode 220a has its cathode tied to the collector of transistor 206a
  • diode 22% has its cathode tied to the collector of transistor 206b
  • the anodes of diodes 220, 220a and 22% are tied together and to the AG-output line 162 from decoder 160.
  • diode 222 has its cathode tied to the collector of transistor 206
  • diode 222a has its cathode tied to the collector of transistor 216a
  • diode 222b has its cathode tied to the collector of transistor 206b
  • the anodes of diodes 222, 222a, and 222b are tied together and to the AY- output line 164 from decoder 160.
  • Diode 224 has its cathode tied to the collector of transistor 216
  • diode 224a has its cathode tied to the collector of transistor 206a
  • diode 224b has its cathode tied to the collector of transistor 216b.
  • diodes 224, 224a, and 224b are tied together and to the BG-output line 166 from decoder 160.
  • diode 226 has its cathode tied to the collector of transistor 206
  • diode 226a has its cathode tied to the collector of transistor 216a
  • diode 226b has its cathode tied to the collector of transistor 216b
  • the anodes of diodes 226, 226a, and 22Gb are tied together and to the BY-output line 168 from decoder 160.
  • line 162 is tied to the anode of diode 228, the cathode of which is connected to the base of NPN-transistor 230.
  • Transistor 230 has its collector tied to a source of positive voltage and its emitter coupled to ground through resistor 232. Resistor 234 couples line 162 to the positive voltage source.
  • the emitter of transistor 230 is connected to the anodes of diodes 236, 237, and 238.
  • Line 91 from the output of memory unit 89, is connected to the anodes of diodes 240 and 242.
  • the cathodes of diodes 236 and 240 are tied together, and the cathodes of diodes 238 and 242 are tied together.
  • Lines 164, 166, and 168 and their respective associated lines 93, 95, and 97 from memory unit 89 are connected to identical logic circuitry within function steering logic 170, and this identical circuitry is shown in FIG. 6 having components bearing reference numbers identical to the reference numerals utilized in the logic circuitry associated with lines 162 and 91 but including the suffix letter a in the logic circuitry associated with lines 164 and 93, the suffix letter b in the logic circuitry associated with lines 166 and 95, and the suffix letter c in the logic circuitry associated with lines 168 and 97. Thus, these latter three logic circuitry units are not described in detail.
  • the cathodes of diodes 237, 237a, 237b, and 2370 are tied together and to output line 239 from function steering logic 170.
  • Input terminal 244 of phase-A green switch 172 is connected to the cathodes of diodes 238 and 242. Within switch 172, terminal 244 is tied to the first side of relay coil 246, the second side of which is tied to ground. Normally open relay contact 246a couples the gate of triac 248 to the first side of resistor 250, the second side of which is tied to the T2 terminal of triac 248. The T2 terminal of triac 248 is connected to output terminal 252 of AG switch 172 which in turn is connected to the first terminal of indicator lamp 254 which provides the phase-A green indication of traffic signal 20.
  • switches 174, 176, 178, 180, and 182 contain circuitry identical with that in switch 172; therefore, this circuitry is not shown in detail, but the input terminals of switches 174-182 are designated 244a-244e, respectively, to correspond with input terminal 244 of switch 172, and the output terminals of switches 174 to 182 are designated 252a-252e, respectively, to correspond with output terminals 252.
  • BR-switch 174 has its input terminal 244a connected to the cathodes of diodes 236, 240, 236a, and 2400 and its output terminal 252a connected to the first side of indicator lamp 256 which provides the phase-B red indication in traffic signal 20.
  • Input terminal 244! of AY-switch 176 is tied to the cathodes of diodes 238a and 242a, while output terminal 252b of switch 176 is connected to the first side of the phase-A yellow indicator lamp 258 within signal 20.
  • input ter minal 244C of BG-switch 178 is tied to the cathodes of diodes 238b and 24217, while output terminal 2520 of switch 178 is connected to the first side of the phase-B green indicator lamp 260 in signal lamp 28.
  • AIR-switch 1811 has its input terminal 244d tied to the cathodes of diodes 236b, 2411b, 238C, and 2420 and its output terminal 252d tied to the first side of the phase-A red indicator lamp 262 in traffic signal 211.
  • BY-switch 182 has its input terminal 2442 tied to the cathodes of diodes 236s and 240C and its output terminal 252e tied to the first side of phase-B yellow indicator lamp 264 in signal 26.
  • the second side of each indicator lamp 254-264 is tied to one side of alternating current source 266 of suitable voltage, for example 1 volts.
  • the T1 terminal of triac 248 is tied to the alternating current ground to which source 266 is referenced. Proper operating time of relays 246 results in the switches 172-182 having soft start and soft stop operation.
  • transistors 2116, 2116a, and 2116b are cut off, and transistors 216, 216a, and 216b are conducting.
  • Each gate 219 has the cathode of at least one of its diodes coupled to ground through a conducting transistor. Accordingly, in this quiescent condition, lines 162, 164, 166, and 168 are each at ground potential, and so transistors 2311, 239a, 230b, and 2300 are cut off. Therefore, diodes 236-236c and 238-238c have their anodes at ground potential, and the relay 246 in each switch 172-182 is deenergized. As a result, the triac 248 in each switch 172-182 is not conducting, and each indicator lamp 254-264 is deenergized.
  • This quiescent condition is not a normal operating condition of the traffic guidance system, but might represent a standby condition in which the signal lamps are inactive.
  • encoder 91 When encoder 91) sends a signal to decoder 168 to initiate a traffic interval, the corresponding indicator lamps are energized.
  • encoding unit 102a receives a pulse on line 82 from AND gate 74 and in response applies a positive voltage to line 92. This turns on transistor 206, cutting off transistor 216 within decoder 161).
  • the cathodes of diodes 220, 2200, and 22Gb are isolated from ground, and positive potential is applied through diode 228 to the base of transistor 230 in function steering logic 170. This turns on transistor 230, applying voltage through diodes 236 and 238 to the relay coils 246 within switches 172 and 174.
  • AND gate 76 activates AY-encoding unit 182b, thereby applying voltage to line 94 and deactivating encoding unit 1020 to remove the voltage from line 92.
  • transistor 206 turns off, transistor 216 turns on, transistor 2116a turns on, and transistor 216a turns off.
  • the AG-line 162 is then connected to ground through diode 220, and so transistor 231 turns off, removing voltage from relay 246 within switch 172 to cause that relay to deenergize and removing voltage from the relay within switch 174.
  • Each of the diodes 22, 222a, and 2221; within the AY-gate 219 has its cathode isolated from ground, and so voltage is applied through diode 228a to turn on transistor 230a. This provides current through diodes 236a and 2380 to switches 174 and 176. Consequently, the relay within switch 174 remains energized, while the relay within switch 176 energizes. The triac within switch 176 then becomes conductive, energizing lamp 258. Lamp 256, of course, remains energized, and so the traffic signal provides the phase-A yellow and the phase-B red indications.
  • Indicators 256 and 258 deenergize at the first negative half cycle of current from source 266 following the opening of the relay contacts in switches 174 and 176.
  • AND gate applies a pulse on line 88 to turn on BY-encoding unit 102d, thereby turning off BG-encoding unit 1020 Voltage is then present on lines 94 and 96, and so BG-line 166 is at ground potential, while BY-line 168 is isolated from ground. Voltage is then applied through diode 228C to turn on transistor 230a.
  • Transistor 2311b cuts off, removing excitation from switches 178 and 1811. Excitation from transistor 2311c is applied to switches 181) and 182, and so indicators 262 and 264 are energized, while indicator 261) is deenergized.
  • an output pulse from AND gate 57 is applied via line 59 through appropriate circuitry to clock 12 to reset the clock to time zero to commence timing the next traffic cycle.
  • memory unit 89 might be a group of bistable multivibrators, one associated with each function AG, AY, BG, and BY.
  • memory unit 89 might be a set of four circuits such as encoding circuits 102, but providing discrete output indications rather than utilizing diodes 138-148.
  • the AG, AY, BG, and BY signals on lines 91, 93, 95, and 97, respectively, are applied to their associated diodes 2411-2400 and 242-2420 in function steering logic 171) to energize switches 172-182 in the same manner as is done by the AG, AY, BG, and BY signals from decoder 160. If the traffic guide is to be located at the intersection, then most likely memory unit 89 would be utilized rather than encoder 90 and decoder 1611. Likewise, the outputs of memory unit 89 can be multiplexed for transmission to function steering logic 17 0 at a remote location.
  • flashing indications can be provided.
  • a pulsing current of, for example, one pulse per second can be applied through input terminal 113b and diode 1119b to resistor 1116b in AY-encoding unit 102b, while a con stant voltage is applied on AY-line 84.
  • a one pulse per second signal appears on line 94, causing AY-indicator lamp 258 and BR-indicator lamp 256 to flash at one hertz.
  • a pulsing current applied to input terminal 113d and a constant voltage on line 88 cause BY-indicator 264 and AR- indicator 262 to flash when an emergency vehicle is to be guided along the phase-B street. lf alternating flashing red and flashing yellow are desired on both streets, then the pulsing current is applied alternately to input terminals l13b and 113d with constant voltage on lines 84 and 88.
  • the computer functions can be applieu .0 input lines 92, 94, and 96 of decoder 160, while clock 12 is inhibited to prevent generation of its timing signals, or while each encoding unit 102 is disabled by a constant voltage on terminals 113a-l13d or by connecting line 239 to these terminals ll3a-ll3d.
  • lines 91, 93, 95, and 97 can be connected to the outputs of variable timers 102a, 102b, 1026, and 102d shown in FIG. 2 of U.S. Pat. application Ser. No.
  • analog timing 826,2l2 if analog timing is preferred.
  • Such analog time signals could be applied as inputs to encoder 90 to permit transmission on two pair of wires, if desired, or a simple network such as diodes 138-148 could be added to the outputs of the analog timing units.
  • the outputs of AND gates 74, 76, 78, and 80 or of memory unit 89 can be utilized in any application in which a cyclic timer is required. Thus, these cyclic outputs could be utilized to control a machine tool operation or to control different lights on an advertising display or for other such cyclic operations. Likewise, the cyclic timing signals can be encoded and decoded by units 90 and 160, respectively, for transmission via two pairs of conductors to a remote location.
  • a single digital clock 12 can be utilized for the several guidance systems, or separate digital clocks 12 can be utilized in each guidance system if these clocks are properly synchronized.
  • traffic guidance systems in accordance with the present invention can be utilized in large intersection systems such as described and depicted in FIG. 4 in U.S. Pat. application Ser. No. 826,212.
  • a cyclic timer comprising:
  • clock means adapted for connection to an alternating current voltage source for providing timing pulses at discrete time intervals
  • a gating circuit having a plurality of input terminals and an output terminal, the output terminal providing an output signal when and only when an input signal is applied to each input terminal;
  • pulse selection means connecting each input terminal of an associated gating circuit to said clock means and capable of applying selected timing pulses from said clock means to the input terminals of said associated gating circuit to cause an output signal at the output terminal of said associated gating circuit in response to a preselected one of the clock means timing pulses;
  • each conversion circuit further comprises memory means connected to the output terminal of the associated gating circuit to provide a function signal when that gating circuit is the most recent gating circuit to have generated a gating circuit output signal.
  • a cyclic timer as claimed in claim 1 further comprising:
  • encoding means connected to said gating circuit output terminals for encoding output signals from said plurality of gating circuits into a lesser plurality of line signals
  • decoding means connected to said encoding means for decoding said line signals into a plurality of function signals corresponding with said gating circuits output signals.
  • a traffic control system comprising:
  • clock means adapted for connection to an alternating current voltage source for providing timing pulses at discrete time intervals
  • a gating circuit having a plurality of input terminals and an output terminal, the output terminal providing an output signal when and only when an input signal is applied to each input terminal;
  • pulse selection means connecting each input terminal of an associated gating circuit to said clock means and capable of applying selected timing pulses from said clock means to the input terminals of said associated gating circuit to cause an output signal at the output terminal of said associated gating circuit in response to a preselected one of the clock means timing pulses;
  • c. memory means connected to the output terminal of the associated gating circuit to provide a function signal when that gating circuit is the most recent gating circuit to have generated a gating circuit output signal;
  • function steering means connected to said memory means for transforming function signals into traffic control commands for each traffic interval at an intersection.
  • a traffic control system as claimed in claim 4 further comprising further switching means connected to said function steering means and adapted for connection to traffic signal indicators and to a power source for switching power to traffic signal indicators in response to traffic control commands.
  • a traffic control system comprising:
  • clock means adapted for connection to an alternating current voltage source for providing timing pulses at discrete time intervals
  • a gating circuit having a plurality of input terminals and an output terminal, the output terminal providing an output signal when and only when an input signal is applied to each input terminal;
  • pulse selection means connecting each input terminal of an associated gating circuit to said clock means and capable of applying selected timing pulses from said clock means to the input terminals of said associated gating circuit to cause an output signal at the output terminal of said associated gating circuit in response to a preselected one of the clock means timing pulses;
  • encoding means connected to said gating circuit output terminals for encoding output signals from said plurality of gating circuits into a lesser plurality of line signals;
  • decoding means connected to said encoding means for decoding said line signals into a plurality of function signals corresponding with said gating circuit output signals;
  • function steering means connected to said decoding means for transforming function signals into trafiic control commands for each traffic interval at an intersection.
  • a traffic control system as claimed in claim 6 further comprising further switching means connected to said function steering means and adapted for connection to traffic signal indicators and to a power source for switching power to the traffic signal indicators in response to traffic control commands.
  • a cyclic timer comprising:
  • each conversion circuit including:
  • a gating circuit having a plurality of input terminals and an output terminal, the output terminal providing an output signal when and only when an input signal is applied to each input terminal;
  • pulse selection means connected to each input terminal of an associated gating circuit and adapted for connection to a source of digital timing pulses and capable of applying selected timing pulses from the source of digital timing pulses to the input terminals of said associated gating circuit to cause an output signal at the output terminal of the associated gating circuit in response to a preselected digital timing pulse;
  • reset means connected to the output terminal of one of said gating circuits and adapted to apply a reset signal to the source of digital timing pulses in response to an output signal on that gating circuit output terminal.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Traffic Control Systems (AREA)
US863309A 1969-10-02 1969-10-02 Apparatus for digital control of traffic control timers Expired - Lifetime US3605084A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86330969A 1969-10-02 1969-10-02
FR7130581A FR2150219A1 (en17) 1969-10-02 1971-08-23

Publications (1)

Publication Number Publication Date
US3605084A true US3605084A (en) 1971-09-14

Family

ID=26216581

Family Applications (1)

Application Number Title Priority Date Filing Date
US863309A Expired - Lifetime US3605084A (en) 1969-10-02 1969-10-02 Apparatus for digital control of traffic control timers

Country Status (3)

Country Link
US (1) US3605084A (en17)
FR (1) FR2150219A1 (en17)
GB (1) GB1264769A (en17)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3810084A (en) * 1971-03-23 1974-05-07 Meyer Labs Inc Electronic traffic signal control system
US3828307A (en) * 1971-06-29 1974-08-06 Georgia Tech Res Inst Automatic traffic control system
US4031507A (en) * 1974-07-02 1977-06-21 The Singer Company Traffic controller, electromechanical sequencer for a traffic controller
US4481515A (en) * 1982-04-01 1984-11-06 Philmont Electronics, Inc. Coordinator for traffic signal controller
US5612596A (en) * 1995-10-16 1997-03-18 Conservation Load Switch, Inc. Conservation traffic control load switch
US7592927B1 (en) * 2005-12-02 2009-09-22 Robert A Marshall System and method for multiplexing traffic signals and bridge collapse detection

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3363185A (en) * 1965-05-04 1968-01-09 Sperry Rand Corp Auxiliary reference signal generating means for controlling vehicular traffic flow or other moving elements
US3423733A (en) * 1967-12-19 1969-01-21 Gen Signal Corp Code communication system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3363185A (en) * 1965-05-04 1968-01-09 Sperry Rand Corp Auxiliary reference signal generating means for controlling vehicular traffic flow or other moving elements
US3423733A (en) * 1967-12-19 1969-01-21 Gen Signal Corp Code communication system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3810084A (en) * 1971-03-23 1974-05-07 Meyer Labs Inc Electronic traffic signal control system
US3828307A (en) * 1971-06-29 1974-08-06 Georgia Tech Res Inst Automatic traffic control system
US4031507A (en) * 1974-07-02 1977-06-21 The Singer Company Traffic controller, electromechanical sequencer for a traffic controller
US4481515A (en) * 1982-04-01 1984-11-06 Philmont Electronics, Inc. Coordinator for traffic signal controller
US5612596A (en) * 1995-10-16 1997-03-18 Conservation Load Switch, Inc. Conservation traffic control load switch
US7592927B1 (en) * 2005-12-02 2009-09-22 Robert A Marshall System and method for multiplexing traffic signals and bridge collapse detection

Also Published As

Publication number Publication date
GB1264769A (en17) 1972-02-23
FR2150219A1 (en17) 1973-04-06

Similar Documents

Publication Publication Date Title
US4443783A (en) Traffic light control for emergency vehicles
US3175191A (en) Binary code signalling system having a binary counter at the receiver responsive to a selected code
US3320585A (en) Time informing display device
US3605084A (en) Apparatus for digital control of traffic control timers
US3925704A (en) Lighting system with variable flashing rate
EP0502489B1 (en) A power supply and control unit for a light system and a lighting unit for the light system
US3480909A (en) Time counting traffic signalling system
US2555994A (en) Traffic signal controller with pedestrian actuation
US3414878A (en) Traffic signal lamp control circuit
RU104136U1 (ru) Устройство автоблокировки с тональными рельсовыми цепями и централизованным размещением оборудования
US4059821A (en) Traffic signal controller flasher for pedestrian clearance
ES355324A1 (es) Sistema electronico de mando automatico de un convoy ferro-viario.
US3710200A (en) Switching control systems
US3267424A (en) Traffic actuated control system
US3528054A (en) Digital control system for traffic signals
GB1412065A (en) Multiphase signal generator
Tyack Street traffic signals, with particular reference to vehicle actuation
US3644884A (en) Modular timer for use in traffic control systems
US3255432A (en) Traffic light control systems
US1946436A (en) Resynchronizing system for master and secondary controllers
US3175184A (en) Static logic power control
SU1049284A1 (ru) Устройство дл управлени тиристорными регул торами параллельных групп т говых электродвигателей
US3775744A (en) Traffic controller with binary counter
FI61771C (fi) Kretsanordning foer trafiksignalanlaeggningar
SU1363367A1 (ru) Устройство дл контрол чередовани фаз в трехфазной сети