US2750576A - Vehicle actuated traffic signal apparatus - Google Patents

Vehicle actuated traffic signal apparatus Download PDF

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US2750576A
US2750576A US306472A US30647252A US2750576A US 2750576 A US2750576 A US 2750576A US 306472 A US306472 A US 306472A US 30647252 A US30647252 A US 30647252A US 2750576 A US2750576 A US 2750576A
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Prior art keywords
lane
relay
interval
capacitor
drum
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US306472A
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William H Beaubien
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General Electric Co
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General Electric Co
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/07—Controlling traffic signals
    • G08G1/08—Controlling traffic signals according to detected number or speed of vehicles

Definitions

  • Vehicle actuated tratlic signal control systems are distinguished. from xed time, or pre-timed, systems'l in that avelcle actuated system initiates alternations of or controls the duration of the right ofway grantedby the traic signals tointersecting trafc lanes in direct: response. tothe presence of vehicles on. one or more of the intersecting lanes.
  • Vehicle ⁇ actuated systems are fully actuated when subject. to actuation in response tovehicle detectors located in all of the intersecting traiic lanes, ⁇ and semiactuated when subject to actuation only in response. to vehicle detectors located in less than all of the intersecting lanes. Fully.
  • actuated traiiic signal control systems may operate so that the right of' way remains upon the trac lane to which it was last called, known as floating operation, or the right of way may alwaysl revert to a selected one of the traffic lanes, known as reverting operation.
  • a fully actuated traiiic signal control system may be operated in the absence of traftc in a normally cyclic standby manner by providing continuous automatic alternation ofthe right-of way by means ot' a timer, traic actuations being operable either to curtailor to extend the right of way intervals of the normally cyclic standby operation.
  • a semi-actuated control system may operate normally cyclically or as a reverting type, the right of way reverting to the lane in which no detectors are provided, but is not operable as a floating system.
  • pre-timed traic signal controllers mustbe preadjusted to careV for one particular preselected traiiic condition.
  • one of twof intersecting streets may be regarded as the major street and accorded more than halfthe cycle time; At some' intersections, however, the relative importance (in traii'icl density) of two intersecting streets maycliange at' different times ⁇ of the day.
  • Vehicle actuated systems generally adapt themselves automatically to such changing conditions with, of course, various degrees of reinement.
  • vehicle actuated traiiic signal control systems of the fully actuated type should be provided with both minimum and maximum right of way intervals on all intersecting lanes, and that semi-actuated traic signal control systems should .be provided With minimum and maximum right of way intervals upon the actuated lane and with a minimum interval on the non-actuated lane.
  • a minimumintervalisas its name implies, the least interval accorded to anylaneonce the green light has been accorded to it.
  • a maximum right ofway interval, as will appear, is necessary to prevent right of way extension intervals demanded by ⁇ cars from holding a right of ⁇ way continuously.
  • ltI is still another object of my invention to provide a new traffic actuated signal control apparatus wherein the limiting right of way interval available to any of a plurality of intersecting traiiic lanes is variable in response to relative traic density on the lanes.
  • a particular object of the invention is to provide, in al semi-actuated or fully actuated traic signalcontrol apparatus, means for extending the limiting right of way interval available on any actuated lane in response to vehiclesapproaching on that lane when grantedv the'right of way.
  • Another object of the invention is to provide, in'a fully actuated traffic signal control apparatus, rneansfor reducing the limiting right of way interval available on any lane in response to traffic approaching on the other lane.
  • a further object of'the invention is the provisionin a fully actuated traiic signal controller, of means for increasing the limiting right of way interval on a moving lane in response t-o traffic approaching on the moving'lane, decreasing said interval in response to traffic approaching on the stoppedlane, and still'retaining an ultimatelimiting time when right of way is automatically removed.
  • a more particular object of the invention is to provide in a vehicle actuated signalling apparatus, means for extending the limiting right of way interval available on any traic lane in accordance with vehicles stored on the lane between the detector and the light prior to the time such right of way was granted.
  • my invention provides a ⁇ vehicle actuated timer which is set into operation,-normally, by the trst'car or other vehicle approachingA the intersection against the red light.
  • the timer may also be set in operation automatically, as by automatic recall in reverting operation.
  • Vehicles approachingona lane having the green light demandV and obtain vincremental extensions of the right ofy way time.
  • a limit, called an extension limit interval is imposed beyond which the right of way time cannotY be extended.
  • this extensiony limiting time is variable in increments both inv accordance with cars approaching on and cars approachproaching against the right of way as in a oating system.
  • My limiting interval has no arbitrarily predetermined duration but is varied incrementally, both by increase and by decrease, in accordance with exlstmg traffic conditions.
  • Even the ultimate limiting time which is imposed despite continued efforts to increase the limit is of no fixed predetermined length, but is measured by the density of traic approaching on all intersecting lanes.
  • I utilize a rotatable signal sequence drum which is provided with a plurality of switching positions and which is turned from one position to another by means of an electric motor. In its various switching positions the sequence drum actuates switches to control the red, amber and green lights in a traic signal device located at the intersection of one or more streets (hereinafter referred to as traffic lanes).
  • the motor driving the sequence drum is controlled by suitable vehicle detectors (i.
  • the detectors are normally positioned an appreciable distance from the intersection (for example 100 to 300 feet), so that vehicles crossing a detector on a lane having the right of way require a clearance time, and vehicles approaching against a red light are stored between the light and the detector.
  • the sequence drum is provided with certain standby or rest positions in each of which the right of way is granted to a different one of the intersecting trac lanes, the number of stand-by or rest positions on the drum corresponding to the number of lanes to which the right of way is granted in a complete cycle of operation. It will be appreciated that in a semi-actuated apparatus only one such position is properly called a stand-by or rest position and the intermediate right of way positions on the drum are more properly called dwell positions. In floating or reverting operation the signal sequence drum normally remains at rest in one of its stand-by positions until it is moved to grant the right of way to another traffic lane in response to actuations of the detector on that other lane. In automatic recall, or normally cyclic, operation, of course, the drum may also be moved Afrom the rest position or positions in response to an automatic call circuit controlled by a manually operated recall switch.
  • the duration of the right of way granted to any actuated traffic lane is made up of an initial time interval determined by the controller in accordance with the number of cars passing over and actuating the detector switch in the stopped street prior to the transfer of the right of way to that street, and in addition one or more vehicle extension intervals which may be added to the initial interval in overlapping time relation in response to actuations of the detector switch by cars approaching the intersection on a lane having the right of way.
  • the timers for determining the period of time that each street has the right of way, in accordance with trac conditions as evidenced by repeated actuation or nonactuation of the car detector switches include a timerA for each street for determining the initial time interval in accordance with the number of cars approaching wherr the particular street does not have the right of way, and for adding to these initial intervals extension intervals: determined by the additional approaching cars after the street is given the right of way by the green light.
  • I also provide an additional timer, transferred by the sequence drum from one street to the other, for imposing a limiting time on the car extension intervals and moreover for transferring the right of way substantially instantaneously if cars are waiting on the stopped street and cease to approach or are widely spaced on the right of way street. It is a feature of my invention as applied to full actuation that the extension limit time interval introduced by this additional timer is progressively reduced in response to cars approaching on the stopped street and progressively increased in response to cars approaching on the right of way street. In a semi-actuated apparatus, I utilize this additional extension limit timer to determine a minimum right of way interval on the non-actuated street.
  • l provide means whereby cars approaching on a stopped lane and thus predetermining a subsequent initial right of way interval on that lane, also increase the maximum extension interval ap plicable to such subsequent right of way interval.
  • the extension limit timer inherently includes anl ultimate timing characteristic beyond which the moving lane cannot hold the right of way.
  • my controller is characterized also in that vehicle extension intervals demanded by cars approaching on the moving lane are not cumulative but are overlapping, each new vehicle extension interval cancelling the remaining portion of the previous extension interval, so that no more than one complete vehicle extension interval is stored in the timer at any one time.
  • This characteristic corresponds to traffic conditions, in that the vehicle interval which is operative is that demanded by the last car to cross the detector, all other significant cars being ahead of this car.
  • Fig. 1 is a schematic circuit diagram of a fully actuated traic signal control system embodying my invention
  • Figs. 2 to 5 inclusive are simplified elementary circuit diagrams of certain significant timing circuits included in Fig. l, these Figs. 2 to 5 being drawn for only one phase of the operation for the purpose of simplification
  • Fig. 6 is a schematic circuit diagram of a semi-actuated trafiic signal control system embodying my invention.
  • the apparatus includes a pair of vehicle detectors, or vehicle responsive switches, 1 and 2 adapted to be positioned beneath or adjacent the intersecting traic lanes.
  • the detector 1 is associated with one lane, A
  • the detector 2 is associated with the other lane, B
  • each detector switch is closed momentarily whenever a vehicle approaching on thev associated lane passes a predetermined point spaced back ⁇ from fthe intersection.
  • a second .detector switch would be in parallel circuit relation with each detector switch l1 and ⁇ 2.
  • a suitable Signal device 3of the type comprising a red,amber and :green indicating light for each intersecting traiiic lane. interposed 4between the detectors 1, 2 and the signal device 3, Tprovide a controller operable in response to actuations of the detectors to control the lights.
  • This controller includes a rotatable signal sequence drum 4 having switch operating cams and sixteen discrete switchingpositions, asindicated schematically inthe drawing, the drum'being advanced by a motor 5.
  • the signal vdrum has associated therewith six cam operated switches, RA, AA, GA, RYB, .AB, GB, connected to control the lights in the .signal device .3.
  • the drum also controls a Vplurality of other -cam operated switches, C1 to C12 inclusive, operable in conjunction with the various'timing circuits, as will be 'hereinafter explained.
  • the controller includes five electronic timers, .each timer including a grid-controlled electron discharge tube, and the .tubes being shown as three element vacuum tubes, T-l, T-Z, T43, T-4 and T45.
  • the timing tube T-l is in the initial interval and vehicle extension interval timer for the lane AA
  • the timing tube T-2 is in the corresponding timer for the lane B.
  • the timing tube T-S is in the extensionlimit vand ltransfer timer, which timer is operable in conjunction with both lanes, while the tube T-4 is in an extension limit increase timer operable in conjunction with both lanes.
  • the tube'T-S is in an amber interval timer also operable in conjunction with both lanes.
  • All 'the timing tubes nare arranged to be normally conductive and are provided With grid vcapacitors which are adapted to maintain the .associated tube non-conductive when negatively charged.
  • Each grid capacitor is provided with one or more discharge resistors through which any negative charge accumulated on the capacitor is permitted at times to de- Cay, thereby to determine certain delay intervals rbefore .tube conduction.
  • the extension limit .and amber timing tubes T-3 and T-S, respectively, are arranged when conductive to effect Vclosure of the drum motor energizing circuit, therebyto move the drum through a singleposition.
  • the extension limit timing tube T-3 is vprovided with aplurality of grid capacitor discharge resistors, and these various discharge resistors are controlled in their connection to the timing capacitor 'C-3 by'means of the extension limitincrease 'timing tube T-4 and one or the other of the initial and vehicle extension interval timing tubes T41, T-2.
  • the timing tubes T-1 to T-5, inclusive are provided with grid capacitors C-1, C-Z, C-3, C-'4 and C-5, respectively, and ⁇ witl1 anode or .plate relays R-l, ⁇ R2, R-3, R-4 and R-S, respectively.
  • the plate relays of the timing tubes T-3 and T-S are connected to controlthe energizing vcircuits for the program drum motor S, while the plate relays of the timing tubes T-l, T-Z and T-4 are connected to control various discharge circuitsfor the extension limit timing capacitor C3.
  • the vehicle detectors 1 and 2 are connected to control :detector relays D-l and D-2, which are connected to beheld closed'for a predetermined fixed impulse interval upon each vehicle detection.
  • the impulse timing of the detector relays is accomplished by a pair of detector timing relays DT-l and DTF-2, respectively.
  • vthere are provided a number of transfer relays controlled 'by various contacts on the sequence drum.
  • a transfer Arelay vTR-l is connected to control the circuit -of the capacitor "C--1 for the timing tube T-1, and a similar transfer relay TR-Z is connected to control the circuit of .the capacitor C-2 for the timing tube T-Z.
  • a .pair of .transfer relays TR-S and 'IR-4 are connected to control the cathode circuits of the extension limit timing tbe T-3 and to transfer the connections of these cir- .cuits in .theinoperation in .conjunction with the alternate operating .phases
  • a Atransfer .relay "FR-5 ] provided to transfer @the connections of the extension limit ⁇ increase and amber interval timing Atubes T4 and T11-5, frespectively, .in .their f different y,phases .of operation, and ,-a transfer .relay ⁇ '1 ⁇ .R-6 is v.provided to transfer connections -of the .chargingcircuits for the timing capacitors C-i ⁇ and .C-.2 as Ythe right of way is:transferredfrom lane-to lane.
  • the drum is .providedwith sixteen switching positions .representing .one complete ⁇ cycle .of operation, positions 3 :and .1-1 .be- :ing the rest positions from which thedrum .w ⁇ ill.not ,ad- Vance without further .traflic actuation or .automatic call.
  • the relays R-1 and R-2 are therefore picked up and the relay contacts are moved into the opposite positions from the positions shown at Fig. 1.
  • the maximum timing capacitor C-3 is charged to maximum voltage, and the tube T-3 is not conductive, both because of such charge and because its cathode circuit is open at the recall switch Rz and at a contact 43a of the plate relay R-2.
  • the full charge on capacitor C-3 exists because a slow rate charging circuit is completed from a voltage divider 7 and a potentiometer 8 (as a source) through contacts 10 and 10a of relay TR-3, a cathode resistor 9, and the grid-tocathode space of the tube T-3. (A similar potentiometer 8a is provided for the opposite operating condition-i. e., drum position 11.)
  • a transfer contact 19C on detector relay D-Z corresponds for lane B detection to contact 19 on D-l.
  • Closure ofthe contacts 19, 19bl completes an energizing circuit from the supply conductor L-1 through a rectilier R and a capacitor 20 to the energizing coil of the detector timing relay DT-.
  • unidirectional current is supplied to pick up and hold energized the timing relay DT-l only for an interval suicient to charge the capacitor Ztl.
  • a resistor 20a shunting the capacitor 20 serves to determine the impulse interval, but so limits current that the relay DT-l will not hold closed after the capacitor is charged.
  • Energization of the relay DT-1 completes a holding circuit for the detector relay D-1 through the normally open contacts 17, 1711 of the relay DT-l. ln this manner the detector relay D-1 is held energized for a predetermined impulse time determined by the charging time of the capacitor 20, regardless of the speed of the vehicle.
  • the timing relay DT-Vl drops out, the holding circuit for the detector relay D-1 is broken and the relay D-1 drops out. In its drop-out, the relay D-1 again closes its normally closed contacts 19, 19a thereby to shunt and discharge the timing capacitor 20.
  • the relay DT-2 operates in like manner for lane B with a capacitor 21 and resistor 21a.
  • This nonconductive interval of the timing tube T-1 represents a vehicle extension interval in the controller during which transfer of the green light away from lane A cannot be effected. Such vehicle extension interval must be sufficient to permit a vehicle moving at some predetermined normal speed to clear the light. Of course, if no car has approached on the stopped lane B, there would be no tendency to transfer the right of way to lane B.
  • This drop-out of the lane A relay R-1 for a vehicle extension interval insures maintenance of the right of way on lane A because it prevents rapid discharge of the extension limit timing capacitor C-3.
  • the capacitor C-S cannot discharge through the resistor 27 even though a normally open contact 29 on the detector relay D-l is momentarily picked up, because the detector relay D-2 is dropped out (to open its contact 30) and contacts 31, 31b on the transfer relay TR-3 are open.
  • the capacitor C-3 is not discharging through the resistor 16 because the charge on C-3 is being maintained through resistor 9 as previously described.
  • the resistor 28 is a relatively small transfer resistor through which the capacitor C-.3, when connected, may dischargein approximately one second.
  • This resistor 23 by thus rapidly discharging the capacitor C-3, effects a substantially immediate transfer of the right of way by rendering the timing tube T-S conductive, as will be pointed out hereinafter.
  • the capacitor C-3 cannot discharge through resistor 28 at least until the relay R-l (which is measuring a vehicle extension interval) is again picked up.
  • This charging circuit may be followed from a point 36 on a potentiometer 37a, 37b, 37e, 37d, through contacts 38, 38a on relay r1R--6, the capacitor C-2, the grid-to-cathode space in 'the discharge tube T-2, the contacts 35, 35b on the detector relay D-2, normally closed contacts 39, 39a on the transfer relay TR-Z, and a variable resistor 40.
  • a similar resistor 40a is provided in the like charging circuit of capacitor C-1. This charging circuit is closed only momentarily by the detector relay D-2 so that a small predetermined impulse or increment of charge is placed upon the capacitor C-2, thereby to render the grid of the discharge tube T-2 negative.
  • this capacitor C-2 by the approach of the rst vehicle on the stopped lane B renders the tube T-2 non-conductive, thereby to drop out the lane B plate relay R2.
  • the relay R-2 drops out, it closes its normally closed contacts 42, 42a and 43, 43a. These contacts 42, 42a prepare a discharge circuit for the eX- tension limit capacitor C-3 through the rapid transfer resistor 28.
  • This discharge circuit remains incomplete so long as cars approaching the moving lane A are retaining the relay R-l dropped out 'to time vehicle extension intervals, thus maintaining the contacts 34, l34b open.
  • the contacts 43, 43a complete connection of the cathode of tube T-3 to the supply line L-2. This connection shunts resistor 9 and potentiometer 8 and thus initiates discharge of capacitor C-3 through the extension limit resistor 16, thereby to begin the timing of an extension limit interval for the moving lane A.
  • the resistor 28 is preferably "of relatively low resistance so that the capacitor C3 discharges throughthis resistor in about one second.
  • the extension limit timing tube T-'3 is krendered conductive so that the associatedplate relay R-3 is picked up and closes its 'normally open contact 47, thereby to complete an energizing circuit for the drum advance motor S from the power supply line L-2 to ground.
  • the extension limit timing ⁇ tube T-3 is rendered conductive as described, 'therebyto pick up its plate relay and energize the motor "5 to advance the drum.
  • VAdvance of thedrum 4 toward position 4imrnediately closes the drumcontact'Cv, thereby to pick up the vtransfer relay TR-4 and open 'the cathode circuit forthetiming tube T-3. Thisrenders -the tube T-3 nonconductive so :that the plate relayR-S is droppedout ⁇ andthernotor 5,.deenergized.
  • a capacitor 48 .connectedin series with a rec'tier 49 across the lmotor 5, and a resistor 50 shunting the rectier 49 a charge stored inthe .capacitor 48 discharges through the motor, thereby to .brake the motor .to a stop atposition 4 of thetdrum.
  • Transfer relay TR-3 When the transfer relay TR-3 picks up, it transfers its selector contact 10 from 10a to 10b thereby to transfer the charging circuit for the extension limit timing capacitor C-3 from a lane A potentiometer 8 to a lane B potentiometer 8a.
  • the transfer relay "fR-3 also transfers its contact 31 thereby to close the contacts 31, ⁇ 31b and open the contacts 31, 31a, thus associating the discharge resistor 27 with lane A rather than with lane B.
  • the purpose and operation of resistor 27 will be described hereinafter.
  • Transfer relay TR-S also transfers a contact 52 from 52a to 52h thereby to transfer control of the cathode circuit of the timing tube T-3 to the lane A rather than the lane B plate relay.
  • relay TR-3 transfers a pair of contacts 53 and 54 to transfer certain capacitor charging circuits from lane A to lane B operation, as will hereinafter become more evident, and transfers a contact 5S.
  • This contact 55 as Well as contacts 56 and 57 (now transferred by relay TR-4), introduces a memory feature into the operation as will be hereinafter more fully described.
  • a charging circuit is complete for the capacitor C-S of the discharge tube T-5, which circuit may be followed from the power supply line L-2, through a voltage divider 58, the capacitor C-S, the grid-to-cathode space of the discharge tube T-S, a resistor 59, the contacts 15, 15b of the transfer relay TR-S, and a potentiometer 60.
  • the potentiometers 6l) and 61 and the voltage divider 58 are so set that when the line L-1 is positive, the tap 58a on the voltage divider 5S is negative with respect to the slider 60a on the potentiometer 60 (or the slider 61a on the potentiometer 61).
  • the point 58a is positive with respect to the slider 61M (or 61a) and grid current flows through the discharge device T-S to charge the capacitor C S to the difference Voltage between the points 58a and 60a (or 61a).
  • the capacitor C-S thus stands charged at the time that the drum moves into position 6.
  • the potentiometer 60 is shunted by resistor 59.
  • the negative charge on the capacitor C-S now leaks olf through resistor 62 and is reduced to the potential difference between that of the power supply line L-2 and the point 58a on the voltage divider 58.
  • the amber timing tube T-5 is retained nonconductive.
  • the capacitor C-S is discharged sufficiently so that the amber timing tube T-S becomes conductive, the associated plate relay R-S is picked up, thereby to close a normally open contact 63 and cornplete an energizing circuit for the duim advance motor 5.
  • this drum contact energized the transfer relay TR-6.
  • this relay transfers several. selector contacts 65, 33 and 66. Transfer of the contact 65 removes line L2 power from two detector timing relay contacts 67 and 68 and places L-2 power upon contacts 34 and 42 of the lane A and lane B plate relays, respectively.
  • Transfer of the contact 38 removes connections of the line L-2 from the point 36 on the potentiometer 37a-37d and connects this line directly to contact 54h on the transfer relay TR-3, and thus through the contact 54 on 'fR-3 (now picked up) and the amber plate relay contact 64 (closed after the amber timing interval) on the contact 53 of the transfer relay TR-3, thereby to prepare for minimum initial interval timing for lane B as will be more fully described hereinafter.
  • drum contact C5 In position 9, the drum contact C5 is opened so that lthe cathode circuit of the amber discharge tube T-S is interrupted, thereby to interrupt conduction of this timing tube, whereupon its plate relay R-S drops out, thereby to open the contact 63 and 64.
  • drum position 9 also, the green light for lane B is energized through the drum contact GB, the red light for lane B is deenergized at the drum contact RB, the amber light for lane A is deenergized at the contact AA, and the red light for lane A is energized through the Contact RA.
  • the drum advance contact C12 In this position 9 of the drum, the drum advance contact C12 is also opened and the drum contact C11 closed.
  • relay TR-2 is picked up, as hereinafter pointed out, and relay TR-6 is also picked up as previously pointed out.
  • contacts 38, 38a of relay TR- and contacts 69, 69a of relay rl ⁇ R-2 disconnect the capacitor C-2 from the normal charging voltage point 36 on potentiometer 37a-37d.
  • closure of contacts 69, 69h of relay rl ⁇ R-2 shunts the portion of potentiometer 37a-37d through a small capacitor 70 and a resistor 71 in series and connects capacitor C-2 to the common point of capacitor 70 and resistor 71.
  • this discharge takes place only down to the point where the voltage of C-2 equals that of potentiometer slider 72 (i. e., if slider 72 is at the initially higher voltage). That is, the timing tube T-2 is maintained nonconductive for a difference interval determined by the extent of the charge previously accumulated on the capacitor C-2 and the voltage of slider 72.
  • relay R-Z picks up, thereby to lenergize the drum motor 5 through a circuit which may be followed from the motor through contacts 32, 32a of relay R-4, a contact 73 of relay TR-Z, contacts 42, 42b of relay R-2, and -contacts 65, 65b of relay TR- to L-2 power.
  • the drum 4 therefore advances to position 10.
  • Initial interval timing-In drum position 10 no change is effected in the lighting circuits.
  • the drum contact C4 is opened.
  • the drum contact C11 is also opened, and the drum contact C3 is opened. Opening of the drum contact C3 disconnects the plates of the lane A and lane B timing tubes T-1 and T-2 from the power supply line L-1 so that these tubes cannot become conductive in drum position 10.
  • This drum position 10 is only a transfer position, for in this position the drum contact C12 is momentarily closed, thereby again to complete an energizing circuit for the drum advance motor 5 and move the drum to position 11.
  • the energizing circuit for the motor 5 is interrupted by re-opening of the drum contact C12 and the plate circuits of the discharge tubes T-1 and T-2 are reconnected to this power supply line L-1 by -reclosure of the drum contact C3.
  • the tube T-Z is now maintained non-conductive because of the negative charge still remaining on the capacitor C-2 (i. e., not dissipated during the difference interval and representing the remainder of the initial interval for lane B). So long as the discharge device T-2 is non-conductive, no transfer of the right of way to lane A can be initiated because of the dropped-out position of the associated plate relay R-2.
  • position 11 on the drum is a normal or rest position in which the right of way is granted to lane B, in the same manner as position 3 is a rest position in which right of way is granted to lane A.
  • Extension limit time decrease It may first be noted that the extension limit time determined by discharge of the capacitor C-3 through the large extension limit resistor 16 is not a fixed time, but is subject to reduction in response to the approach of vehicles on the stopped lane. This is done by momentarily connecting the discharge resistor 27 in parallel circuit relation with the resistor 16 each time that a vehicle approaches the intersection on the stopped lane, thereby more rapidly to discharge C3 in recurring increments. It may be observed that such parallel connection is effected either through the contact 29 of the lane A detector relay D-l, or the contact 30 of the lane B detector relay D-Z, one or the other of these contacts being selected by the contact 31 on the transfer relay 'TR-3.
  • the relay TR-3 is energized through the drum contact C9 so that the contact 3l is closed on the contact 31h.
  • the lane B detector relay contact 30 is therefore disconnected from the circuit and the stopped lane A detector relay contact 29 is connected in circuit, thereby to connect the discharge resistor 27 in parallel circuit relation with the resistor 16 momentarily each time that the detector relay D-1 is picked up for a predetermined impulse interval by the detector 1 on lane A.
  • the extension limit interval for which the green light may be held by cars approaching the intersection on the moving lane is progressively reduced as more and more cars accumulate between the intersection and the detector on the stopped lane.
  • Extension limit time increase In addition to the foregoing, the extension limit time determined by the discharge of capacitor C-3 through resistors 16 and 27 is subject to increase in response to cars approaching the intersection on the moving lane by the operation of the extension limit increase timing tube T-4 in the following manner.
  • the extension limit increase circuit of Fig. l is shown in simplified form at Fig. 3, using the same reference numerals as at Fig. l and showing only components used with lane A green.
  • timing tube T-4 is normally Vconductive so that its plate relay R-4 is normally picked up, thereby normally to connect a discharge resistor 74 in parallel circuit relation with the extension limit resistor 16.
  • the cathode circuit for the timing tube T4 may be followed from the cathode through the selector contact 13 on the transfer relay TR-S and then through one or the other of the detector timing relay contacts 67, 68, to the power supply conductor L-Z through the transfer contact 65 on the transfer relay TR-6.
  • the discharge tube T-4 is conductive.
  • the discharge tube T-4 is provided with a grid capacitor Ced across which is shunted a discharge resistor 7S, one end of the capacitor C-4 being connected to an intermediate point 76 on a potentiometer 77a, 77h, 46.
  • the contact 67 or 68 connects the cathode of the discharge device T-4 to the sliderv 77 on the potentiometer 77a, 77h, 46 on the opposite side of ground from the point 76.
  • the extension limit increase timing tube T-4 is normally conducting.
  • the detector relay D-2 Upon actuation of the detector in the moving lane, for example, in drum position 11 on lane B, the detector relay D-2 is picked up and the detector timing relay DT-il is picked up.
  • the relay DT-Z When the relay DT-Z is picked up, the cathode circuit of the tube T-4 is interrupted at the contact 68 and the same contact connects the cathode of the tube T-4 to the point 77 on the potentiometer 77a, '77b, 46. This causes the capacitor C-4 to be charged on half cycles when the line conductor L-2 is positive, thereby to render the grid of the discharge tube T-4 negative.
  • the tube T4 is retained non-conductive sufficiently long for the predetermined charge to leak off the capacitor C-4.
  • the plate relay R-4 is dropped out, thereby to discon neet the discharge resistor 74 from its normal parallel circuit relation with the extension limit resistor 16. In this manner, the rate of discharge of the extension limit capacitor C-3 is temporarily reduced, thus increasing the extension limit interval in response to detector actuations on the moving lane.
  • This ultimate discharge time is, of course, not of fixed predetermined duration, but depends upon trac conditions.
  • the ultimate limit is, of course, simply a mode of operation of the extension limit timer, so that for any particular tratiic condition the limit time is fixed.
  • continuous effort is made to increase the extension limit time by removing resistor 74 from the discharge circuit of capacitor C-3.
  • resistor 74 is, continuously held Vdisconnected, and resistor 27 never connected in circuit, the capacitor C-3 will ultimately discharge through capacitor 16 and will impose an ultimaterlirniting time. Under the one extreme condition assumed, of course, this ultimate time is predetermined.
  • Fig. 4 shows a simplified circuitdiagram of the extension of transfer timerT- for one half rcycle of operation, using the same reference numerals as at Fig. 1.
  • variable potentiometers 79 and d0 the operable po tentiometer for each lane operation being selected by the contact 53 on relay TR-3.
  • a charging circuit for initial interval charging is completed during right of way transfer operation.
  • transfer relay TR-6 is picked up in drum positions 6 9, inclusive, to complete a charging circuit for capacitor C2 which may be followed from the slider 79a of potentiometer 79 through contacts 53, 53h of relay 'fR-3, contact 64 of amber plate relay R-S (which picks up in drum position 6 after timing the amber display), contacts 54, 54b of relay 'FR-3, contacts 38, 38]) of relay "fR-6, capacitor (2 2, the grid-tG-cathode space of tube T-Z, and contacts 35, 33a of relay D-1 to line L-Z.
  • the like operation for reverse transfer of the right of way will be evident to those skilled in the art.
  • switch R1 registers an automatic recall of right of way to lane A in the same manner as the memory operation described above.
  • Switch R1 also completes the cathode circuit of tube T-3 so that T-3 will conduct to initiate a re-transfer of right of way to lane A as soon as all eX- 1S tension time on lane B has expired (i. e., C-3 is discharged) despite the fact that no actuation has occurred on lane A to drop out relay R-l.
  • FIG. 6 I have illustrated certain features of my invention as embodied in a semi-actuated traflic signal control apparatus.
  • the apparatus illustrated at Fig. 6 is applicable to the intersection of a pair of traffic lanes, and it will be understood from the foregoing that only the minor lane B is provided with a detector.
  • the apparatus illustrated at Fig. 6 bears a general resemblance to that illustrated at Fig. l in that there is provided a vehicle detector 101 adapted to be positioned beneath or adjacent the roadway on the minor traiiic lane B, a signal indicating device 102, a rotatable signal sequence drum 103, and a plurality of electronic timing tubes T-ll, T-3l, T-lll and T-Sli for controlling the advance of the drum to vary the display of signal lamps in response to actuations of the detector.
  • the signal sequence drum 193 is connected to be advanced in steps by a motor 16d having a braking circuit 105' similar to that shown at #i3-S0 ol' Fig. l.
  • a motor 16d having a braking circuit 105' similar to that shown at #i3-S0 ol' Fig. l.
  • the signal sequence drum 1113 is provided with six signal lamp switches RA, AA, GA, RB, AB, and GB.
  • the drum is provided with a plurality of other cam switches C2i, C22, C23, C24, C25, C26 and C27 which are operable in conjunction with the various timing circuits in a manner which will hereinafter be explained.
  • the controller of Fig. 6 includes four electronic timers each including a grid controlled electron discharge tube, such as the three-element vacuum tubes 1111, Te31, T-41 and T-Sl.
  • the timing tube T-ll is arranged to time the initial interval and vehicle extension intervals for the minor lane B.
  • the timing tube T-31 is in an extension limit and transfer timer and corresponds in a general way to the timing tube T-3 of Fig. 1.
  • the extension limit timing function of the tube T-31 is applicable only to the minor lane B in the case of Fig. 6.
  • the timing tube T-41 is in an extension limit increase timer and corresponds in a general way to the timing tube T-4 of Fig.
  • timing tube T-'Sl is in an amber timer for both streets and corresponds to the timing tube T-S of Fig. l.
  • the timing tube T-31 opcrates to time a xed initial or minimum interval for the major lane A.
  • means are provided in the apparatus of Fig. 6 for incrementally reducing this lane A minimum time in response to actuations of the Vdetector 101 on lane B when that lane is stopped.
  • each of the timers including the tubes T41, T41, T-41 and T-51 includes also a grid capacitor which when charged maintains the tube nonaconductive, and one or more discharge resistors adapted to be connected across the capacitors.
  • the tube T-ll is provided with a grid timing capacitor C-11
  • the tube T31 is provided with a grid capacitor C-31
  • tube T-ll is provided with a grid capacitor C-41
  • the tube T-S1 is provided with a grid capacitor C-51.
  • the timing tubes are provided with anode or plate relays iii-11, R-31, R-41, and R-Sl, respectively.
  • the detector lill is connected to control a detector timing relay DT-ll, and the relay DTll is connected to control a detector relay D-ll.
  • Impulse timing of the relay DT-11 is accomplished by a simple series capacitor 107.
  • three transfer relays r.FR-11, TR-Zll and TR-31 controlled 'respectively by the drum contact C22, C25,
  • Power is supplied to the timers, relays, lights and drum motor from a transformer T-1 through power supply lines L-1 and L-2, the center of the transformer secondary winding being grounded.
  • the signal sequence drum 103 is provided with six switching positions representing one complete cycle of operation. Since the apparatus is of the semi-actuated type, only a single position of the drum is a normal rest position.
  • the normal rest position is position 1 in which it will be noted that the green signal is granted to the major lane A through the drum switch GA, and the red signal is displayed to the minor lane B through the drum switch RB. It will be evident, of course, that since no detector is provided in the major lane A, the drum will remain in position 1 and no change will be eifected in the signal display so long as no tratiic approaches on the minor lane B, regardless of the amount of traic o-n the major lane A.
  • the drum is provided with a dwell position (position 4), in which the right of way is accorded to lane B for a time determined by the density of traffic o-n lane B, as will appear hereinafter.
  • Fig. 6 reverting- Transfer lane A lo lane B position 1 and that no traffic actuations have taken place for a considerable length of time so that the entire apparatus is in a steady-state or standby condition.
  • the initial and extension interval timing tube for lane B, T-11 is conductive since the lane B recall switch R21 (closed for reverting operation) connects the cathode of T-11 to line L2, and the timing capacitor C-11 is connected to a point 122 on potentiometer 123a, 123b, 123C, which point is positive with respect to line lf2 when line L-l is positive.
  • the discharge tube T-31 is also conductive.
  • the cathode is connected directly to the supply line L-2 through drum co-ntact C24, and the grid is connected through the capacitor C-31 to a point 110 on a potentiometer 109er, 109b, 109C, the point 108 being positive with respect to L-2 when L-1 is positive.
  • the discharge tube T-41 is maintained conductive for a similar reason, i. e., the cathode is connected directly to L-2 through contacts 135, 135a on relay T11-21, while the grid is connected to a point 112 on a voltage divider 115e, 115b, 115C.
  • the discharge tube F1-51 is maintained non-conductive, both because its cathode circuit is open at the drum contact C27, and because a potentiometer 116:1, 116i), 116C is connected between the cathode of tube T-51 and the capacitor C-Sl through a resistor 117 and the contacts 118, 118b of the relay TR-31 in a manner to maintain the grid negative with respect to the cathode when the line L-l is positive.
  • the detector switch 101 is closed momentarily, thereby to complete an energizing circuit for the detector timing relay DT-11 from the supply line L-2 through a rectifier R', the switch 101, a capacitor 107, a resistor 119, and the actuating coil of the relay DT-11.
  • the relay DT-11 is energized only so long as current flows through this circuit to charge the capacitor 107.
  • a resistor 132 shunting capacitor 107 is so large that insufficient current flows through it to hold the relay DT-ll picked up.
  • the relay DT-11 While the relay DT-11 is thus picked up for an impulse interval, it closes its contact 120, thereby to complete an energizing circuit from the supply line L-Z for the actuating coil of the detector relay D-11.
  • the relay D-11 picks up, it opens its normally closed contacts 121, 121a and closes its normally open contacts 121, 121b. Opening of the contacts 121, 121a interrupts the cathode circuit for the discharge tube T-11 and renders this device non-conductive so that the plate relay R-11 drops out.
  • drum position 2 no change is effected in the lighting circuits, as will be evident from the diagrammatic representation of the drum, but the drum contacts C21, C23, C25 and C26 are closed, while the drum contact C2.; is opened. Closure of drum contact C21 shunts the detector switch 101, thereby again to pick up relays DT--11 and D-11 for a second impulse interval and thus to add a second increment of initial interval charge to capacitor C-11.
  • This automatic charging impulse insures a sutilcient initial interval in the event that right of way is returned to lane B by the memory circuit described hereinafter.
  • Closure of the drum contact C23 short circuits a resistor' 112 in the charging circuit of the capacitor C-31. @pening of the drum contact C24 interrupts the cathode circuit of the discharge tube T-31 thereby to render this device non-conductive and to render the charging circuit for C-31 operable. Closure of the drum contact C25 com'- pletes an energizing circuit for the relay TR-21. This relay therefore picks up and remains energized through drum positions 2, 3 and 4 as will appear from the drum diagram. When the relay TR-21 picks up, it closes its contacts 11141111, thereby to transfer the charging circuit for the extension limit timing capacitor C-31.
  • This charging circuit may now be followed from the point on the potentiometer 109a-109c through the capacitor C31, the grid-to-cathode discharge space of the timing tube T-31, the drum contact C23 and the contacts 111, 11111 on the relay 'fR-21 to a slider 132 on a potentiometer 133 connected in parallel circuit relation with the potentiometer section 109:1.
  • the capacitor C-31 is charged to a voltage representing an extension limit interval with the right of way on lane B.
  • Drop-out of the plate relay R-31 and consequent opening of the Contact 130 interrupt the drum motor ener- 2i gizing circuit so that the motor is braked to' a stop at position 2.
  • the motor 104 is, however, again energized in drum position 2 by closure of drum contact C26 so that the drum is advanced from position 2 to position 3.
  • drum contact C21 is open, thereby to interrupt the energizing circuit for relay DT-11, which relay, however, was already dropped out by action of the blocking capacitor 107.
  • the relay D-11 being dropped out, completes the cathode circuit of the discharge tube T-11.
  • This discharge tube does not, however, conduct since the capacitor C-11 is now negatively charged and provided with no discharge path.
  • drum contact C23 opens, thereby to unshunt the charging resistor 112.
  • the drum contact C24 is reclosed thereby to reconnect the cathode of the discharge tube T31 to the negative power supply line L-Z, and thus permits the capacitor C-31 to begin discharging through resistor 129 and 12951 in parallel, thereby to time the lane B extension limit interval.
  • drum contact C27 is closed in drum position 3, thereby to connect the cathode ofthe amber timing tube T-Sl to the power supply line L-2.
  • the tube T-51 does not immediately conduct because the capacitor C-51 stood negatively charged by reason of its connection to the potentiometer 116a-116c through the resistor 117 and the contact 118, 118b of relay Til-31.
  • Capacitor C-Sl now begins to discharge through the parallel-connected resistor 136 to time the amber display interval.
  • the discharge tube T51 conducts and energizes its plate relay ETSI.
  • the relay R-Sl picks up, it closes its normally open contact 137 thereby to complete an energizing circuit for the motor 104 and advance the drum from position 3 to position 4.
  • drum contact C27 is opened thereby to interrupt the cathode circuit of the timing tube T-51 and render this tube non-conductive. Opening of the drum switch RB also deenergizes the relay TR-31 so that this relay drops out and closes its contacts 11.8, 118m.
  • Potentiometer 13S is adapted to determine a charge on the capacitor C-il suitable for timing the amber interval on lane B, as will hereinafter appear, while potentiometer 115g determines the lane A amber interval.
  • drum contact C22 is closed thereby to complete an energizing circuit for the transfer relay TRell.
  • the relay rlR-lli picks up, it closes its contact 139a thereby to connect across the timing capacitor C-11 a discharge resistor 139.
  • the capacitor C-11 begins immediately to dissipate its negative charge, thereby to time the initial right of way interval for lane B, as will be evident from the foregoing description of Fig. 1.
  • Pick-up relay TR-ll also transfers its contact 124 from 124g: to 124b, thereby to substitute in the charging circuit of the capacitor C11 a potentiometer section 123e for the potentiometer previously referred to.
  • This provides a new charging circuit for capacitor C-11, adapted to determine vehicle extension intervals whenever relay D-11 is picked up by cars approaching on lane B while it has the right of way.
  • each actuation of detector 101 when lane B has the right of way picks up relays DT-11 and D-11 for a single impulse interval in the manner already described.
  • Relay D-11 when picked up interrupts the cathode circuit of tube T-11 at contacts 121, 121a and completes a charging circuit for capacitor C-11 at contacts 121, 121b.
  • the capacitor C-11 is thus charged to a voltage representing a single vehicle extension interval and retains the tube T-11 nonconductive for such interval. This action is repeated by each vehicle approaching on lane B when it has the right of way. It will be understood that so long as tube T-11 is non-conductive, the relay R11 is dropped out and precludes re-transfer of the right oi way to lane A because contact 127 of relay R-11 is thus held open to prevent short circuiting and rapid discharge of extension limit capacitor C-31 (which is presently discharging slowh ly through resistors 129 and 129e to time the vehicle eX- tension limit interval).
  • the capacitor C-41 is negatively charged by grid conduction on half cycles when L-1 is negative so that when contact 134 of relay D-11 reconnects the cathode of tube T-41 to line L-2, the tube r1141 remains non-conductive until the capacitor C-41 discharges through its shunting resistor 140.
  • the plate relay R-41 is dropped out and opens its contact 141 to unshunt the extension limit resistor 129, as described in connection with Fig. 1, thereby to increase the extension limit time.
  • the drum is moved off of position 4 when the timing tube T-11 again becomes conductive as determined by the discharge interval of the capacitor C-11. Now, therefore, when the initial interval charge and all extension interval charges on the capacitor C-11 are dissipated, the tube T-11 is again rendered conductive.
  • the plate relay R-11 is picked up, thereby to open the contact 126 and close the contact 127. Opening ofthe contact 125 has no effect, but closing of the contact 127 completes a short circuit around the extension limit timing capacitor C-31, thereby immediately to discharge the capacitor C-31 and render the timing tube T-31 conductive.
  • This short circuit may be followed from the grid of the tube r[-31, through the contacts 128, 128b of the transfer relay TR-21 and the contact 127 of the relay R11 to the other side of the capacitor C-31.
  • Extension limit timing-It may here be noted that in the event that vehicles continue to actuate the detector 101 while lane B has the right of way and with sufficient frequency that vehicle extension intervals are continuously demanded in Overlapping relation so that the timing tube T-11 never does become conductive, the extension limit capacitor C-31 eventually becomes discharged through the extension limit timing resistors 129, 129e.
  • the tube T-31 is therefore rendered conductive either by reason of conduction of the tube T-11 after expiration of the initial and all vehicle extension intervals (and consequent short circuiting of capacitor C-l), or by reason of the discharge of capacitor C-31 through the extension limit resistors 129, 129:1.
  • Mininmm l1tervCll.-ln drum position 5 the drum contact C22 is opened, thereby to deenergize the transfer relay rI ⁇ R-11.
  • the relay Til-11 drops out, it transfers its contact 124 to reconnect the charging circuit of the capacitor C-11 to the potentiometer 140, the initial interval charging potentiometer.
  • the drop-out of the relay TR-11 also opens the contacts 139g, thereby to interrupt the discharge circuit of the timing capacitor C-11.
  • the drum contact C25 is also opened, thereby to deenergize the transfer relay 'TR-21 and restore it to its initial position, described in connection with drum position l.
  • drum contact C24 As further appears from an examination of the drum diagram, movement of the drum to position effects no change in the lighting circuit but opens the drum contact C24 and closes the drum contact C23. Opening of the contact C24 interrupts the cathode circuit of the discharge tube T-31, thereby to render this tube non-conductive, drop out the plate relay R-31, and open the motor energizing contact 139. Mornentary closure of drum contact C23 completes a charging circuit for capacitor C-31 from the potentiometer 109m. Through this circuit, capacitor C-31 is charged to a voltage representing a minimum right of Way interval on lane A, in much the same manner as it is charged through drum contact C22 in drum position 2 to the maximum extension limit voltage. In drum position 5, however, the energization of the motor 104 is maintained through closure of the drum contact C26. The drum therefore advances from position 5 to position 6.
  • Drum position 6 is the lane B amber interval, and the drum remains in this position for a length of time de termined by the operation of the amber timing tube T-51. It will be noted that in drum position 6 the red light remains on lane A but the green light is discontinued on lane B and the amber light on lane B substituted therefor. Opening of thc drum contacts C in drum position 6 interrupts energization of the drum advance motor 104, so that the motor is braked to a stop in position 6.
  • drum position 6 the drum contact C23 is opened and the drum contact C24 closed, thereby to reconnect the cathode of the tube T-31 to the power supply line L-Z and initiate discharge of the timing capacitor C-31 through the resistors 129 and 12961 in parallel.
  • the discharge interval of the capacitor C-31 which is thus initiated represents the minimum right of way interval for lane A.
  • drum position 6 also, the drum contact C27 is closed thereby to complete the cathode circuit for the amber timing tube T-S1.
  • the amber timing capacitor C-51 thus begins to discharge through the resistor 136 from the charging voltage determined by the potentiometer 138, in the same manner as it previously discharged in drum position 3 from the voltage determined by the potentiometer 116e.
  • the discharge tube T-Sll thus remains non-conductive in drum position 6 until the capacitor C-51 is discharged. This discharge represents the amber timing interval for lane B.
  • the tube T-Sl becomes conductive, thereby to energize its plate relay R-51 and complete an energizing circuit for the drum advance motor 16-4 through the contacts 137.
  • the motor 164 thus being energized, the drum advances from position 6 to position 1.
  • the drum contact C27 is opened, thereby to interrupt the cathode circuit for the tube T-51 and render that tube non-conclue tive.
  • Drop-out of the associated plate relay R-Sl interrupts the motor energizing circuit and the motor 1M is braked to a stop in drum position l.
  • Lane A is not provided with a detector so that no initial interval or vehicle extension intervals are operative in connection with the lane A right of Way interval.
  • a minimum right of way interval for lane A is provided by charging the capacitor C-31 from potentiometer 1t9a in drum position 5. Until this charge is dissipated, the discharge tube T-31 cannot become conductive and the plate relay R-31 remains dropped out. So long as the relay R-31 is dropped out, its contact is open and no energizing circuit can be completed for the drum advance motor 104, even though the tube T-11 is rendered non-conductive by actuation of the lane B detector.
  • the minimum interval may be shortened by actuations of the detector 101 on the stopped lane B.
  • the lane A minimum interval is determined by discharge of the capacitor C-31 through resistors 129 and 12911 in parallel. It will now be observed that with the transfer relay TR-21 in its dropped-out position, momentary pick-up of the detector relay D-11 for an impulse interval upon each actuation of the lane B detector completes, through a contact 142, a shunt circuit for the capacitor C-31 through a resistor 143.
  • This shunt circuit may be followed from the grid of the tube T-31 through the contacts 128, 128g of the relay TF1-21, the contact 142 of the relay D-11, and the resistor 143 to the other side of the capacitor C-31.
  • the resistor 143 is momentarily connected in parallel circuit relation with the discharge resistors 129, 12.9(1, thereby momentarily to accelerate the discharge of the capacitor C-31. 1n this manner, vehicles approaching the stopped lane B during the lane A minimum right of way interval are effective to decrease this minimum interval in increments.
  • cyclic operation of the controller shown in Fig. 6 may be effected by opening the recall switch R21.
  • the switch R21 When the switch R21 is opened, the cathode circuit of the tube T-ll is interrupted so that the plate relay R-l remains dropped out at all times, thereby to leave the contacts 126 continuously closed.
  • Continous closure of the contact 126 acts as a recall of the right of way to lane B so that the apparatus continually goes through a cyclic alternation of the right of way, even in the absence of vehicle actuation.
  • actuation of the lane B detector 101 while lane A has the right of way, reduces the lane A minimum interval, in the same manner previously described.
  • actuations of the lane B detector i when lane B has the right of way introduce vehicle extension intervals and increase the lane B extension limit time in the same manner previously described.
  • a vehicle actuated traic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting trac lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on at least one of said lanes, means controlled by said vehicle actuated device when said lane has said stop indication for actuating said signal switching means to accord said go indication to said lane, timing means controlled by said vehicle actuated device when said lane previously had said stop indication for predetermining au initial go indication interval on said one lane, means responsive to each actuation of said vehicle actuated device when said one lane has said go indication for controlling said timing means to extend said go indication beyond said initial interval and until a predetermined time after said actuation, and separate timing means controlled by said switching means and operable after a limiting interval to render said rst timing means ineffective to extend said go indication and to operate said signal switching means to remove said go indication from said one lane.
  • a vehicle actuated traiiic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, signal switching means connected to accord said go indication successively to said lanes, means actuated by each vehicle approaching said device on a lane having a go indication to extend said go indication, timing means operable after a limiting interval to render said extending means ineffective, and means actuated by each vehicle approaching said device on a lane having a go indication to increase said limiting interval.
  • a vehicle actuated traiic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traitic lanes, signal switching means connected to accord said go indication successively to said lanes, means actuated by a vehicle approaching said device on a lane having a go indication to extend said go indication, timing means operable after a limiting interval to render said extending means ineliective, and means actuated by each vehicle approaching said device on a lane having a stop indication to reduce said limiting interval.
  • a vehicle actuated tra'ic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traiiic lanes, signal switching means connected to accord said go indication successively to said lanes, means actuated by each vehicle approaching said device on a lane having said go indication to extend said go indication, timing means operable after a limiting interval to render said extending means ineffective, means actuated by each vehicle approaching said device on a lane having a go indication to increase said limiting interval, and meansactuated by each vehicle approaching said device on a lane having a stop indication to reduce the said limiting in- 27 terval then running on the lane having said go indication.
  • a vehicle actuated trac signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on at least one of said lanes, an electron discharge device having an anode, a cathode and a control electrode, means responsive to conduction of said discharge device for actuating said signal switching means to transfer said go indication from one lane to another, timing means including a capacitor connected to said control electrode for maintaining said discharge device non-conductive when said capacitor is charged, means controlled by said vehicle actuated device when Said one lane has said go indication for charging said capacitor to a predetermined voltage upon each vehicle actuation, and second timing means for rendering said first timing means ineffective to extend said go indication and for actuating said signal switching means to remove said go indication from said one lane after a limiting right of way interval.
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on at least one of said lanes, an electron discharge device having an anode, a cathode and a control electrode, means responsive to conduction of said discharge device for actuating said signal switching means to transfer said go indication from one lane to another, timing means including a capacitor connected to said control electrode for maintaining said discharge device non-conductive when said capacitor is charged, means controlled by said vehicle actuated device when said one lane has said stop indication for incrementally charging said capacitor to a voltage proportional to the number of vehicles actuating said vehicle actuated device, means controlled by said vehicle actuated device when said one lane has said go indication for charging said capacitor to a predetermined voltage upon each such vehicle actuation, and second timing means for rendering said first timing means ineffective to extend said go indication and for actuating said signal switching means to remove said
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting trac lanes, signal switching means connected to accord said go indication successively to said lanes, means actuated by a vehicle approaching said device on at least one of said lanes when said lane has said stop indication for actuating said signal switching means to accord said go indication to said one lane, first timing means controlled by said signal switching means to retain said go indication on said one lane for at least an initial interval, means responsive to each additional actuation of said vehicle actuated means while said one lane has said go indication for controlling said first timing means to extend said go indication, second timing means controlled by said signal switching means for rendering said first timing means ineffective to extend said go indication and for operating said signal switching means to remove said go indication from said one lane after an extension limiting interval, and means responsive to each said additional actuation for incrementally increasing said extension limiting interval.
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, signal switching means connected to accord said go indication successively to said lines, a vehicle actuated device on at least one of said lanes, means controlled by said vehicle actuated device when said one lane has said stop indication for actuating said signal switching means to accord said go indication to said one lane, second switching means for actuating said signal switching means to remove said go indication from said one lane, first timing means for disabling said second switching means, means controlled by said vehicle actuated device when said one lane has said stop indication for controlling said first timing means to retain said go indication upon said one lane for at least an initial interval after accord to said one lane, means responsive to each additional actuation of said vehicle actuated device while said one lane has said go indication for controlling said first timing means to extend said go indication for a predetermined interval after each such actuation, second timing means controlled by said signal switching means for rendering said first timing means ineffective to extend said
  • a vehicle actuated handles signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traflic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on at least one of said lanes, means controlled by said vehicle actuated device when said one lane has said stop indication for actuating said signal switching means to accord said go indication to said one lane, second switching means for actuating said signal switching means to remove said go indication from said one lane, first time element means for disabling said second switching means, means responsive to actuations of said vehicle actuated device when said one lane has said stop indication for controlling said first time element means to maintain said go indication on said one lane for at least an initial interval after accord thereto, means responsive to each actuation of said vehicle actuated device while said one lane has said go indication for controlling said first time element means to extend said go indication for a predetermined interval following each such actuation, second time element means controlled by said signal switching means for rendering
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traiiic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each said lane, second switching means controlled by the vehicle actuated device on a stopped lane for operating said signal switching means to accord said go indication to that lane, first timing means controlled by the vehicle actuated device on each lane prior to accord of said go indication to that lane to retain said go indication on that lane for at least an initial interval after accord of said go indication, second timing means controlled by the vehicle actuated device on a moving lane for rendering said second switching means ineffective to operate said signal switching means for an extension interval after each moving lane actuation, third timing means controlled by said signal switching means for rendering said second timing means ineffective to extend said go indication after an extension limiting interval, and means controlled by said vehicle actuated device on a moving lane to incrementally increase said extension limiting interval.
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each said lane, second switching means controlled by the vehicle actuated device on each lane when stopped for actuating said signal switching means to accord said go indication to that lane, an electron discharge device controlled by the vehicle actuated device in each lane and each including an anode, a cathode and a control electrode, means controlled by said signal switching means for connecting the discharge device associated with a moving lane when conductive to render said second switching means effective to remove the go indication from that lane, means responsive to the vehicle actuated device on a moving lane for controlling the control electrode potential of the associated discharge device to render said discharge device non-conductive for a predetermined interval following each such vehicle actuation, timing means for rendering said second switching means effective to remove said go indication from a moving lane after an extension limiting interval independently of conduction of
  • a vehicle actuated trafiic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, electroresponsive signal switching means connected to accord said go indication successively to said lanes, an electron discharge device having an anode, a cathode and a control electrode, means operable upon conduction of said discharge device to actuate said signal switching means to transfer said go indication from a first to a second lane, a capacitor connected when charged to maintain said control electrode negative with respect to said cathode thereby to render said discharge device nonconductive, a resistor connected across saidr capacitor to control the discharge thereofV thereby to time an interval, a second resistor adapted to be connected in shunt circuit relation with said first resistor, and means controlled by vehicles approaching said signal device on at least one of said lanes for controlling said shunt circuit connection thereby to control the rate of discharge of said capacitor and the'length of said interval.
  • a vehicle actuated handles signal control apparatus including a signal device providing stop and go indications for each ofv a plurality of intersecting tratic lanes, electroresponsive signal switching means connected to accord said go indication successively to said lanes, an electron discharge, device having an anode, a cathode and a control electrode, means operable upon conduction of said discharge device to actuate said signal switching means to transfer said go indication from a first to a second lane, a capacitor connected when charged to maintain said control electrode negative with respect to said cathode thereby to render said discharge device nonconductive, a resistor connected across said capacitor to control the discharge thereof thereby to time an interval, and means controlled by vehicles approaching said signal device on at least one of said lanes for momentarily connecting in shunt circuit relation with said resistor a second resistor thereby incrementally to reduce the length of said interval.
  • a vehicle actuated traic signal control apparatus including a signal device providing stop and go indications for each of a plurality of Aintersecting traflic lanes, electroresponsive signal switching means connected to accord said go indication successively to said lanes, an electron discharge device having an anode, a cathode and a control electrode, means operable upon conduction of said discharge device to actuate said signal switching means to transfer said go indication from a first to a second lane, a capacitor connected when charged to maintain said control electrodenegative with respect to said cathode thereby to render said discharge device nonconductive, a resistor connected across said capacitor to control the discharge thereof thereby to time an interval, and means controlled by vehicles approaching said signal device on at least one of said lanes for momentarily disconnecting said resistor from said capacitor thereby to reduce the rate of discharge of said capacitor and incrementally increase the length of said interval.
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traiiic lanes, electroresponsive signal switching means connected to accord said go indication successively to said lanes, an electron discharge device having an anode, a cathode and a control electrode, means operable upon conduction of said discharge device to actuate said signal switching means to transfer said go indication from a first to a second lane, a capacitor connected when charged to.
  • a vehicle actuated trafiic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, electroresponsive signal switching means connected to accord said go indication successively to said lanes, an electron discharge device having an anode, a cathode and a control electrode, means operable upon conduction of said discharge device to actuate said signal switching means to transfer said go indication from a first to a second lane, a capacitor connected when charged to maintain saidcontrol electrode negative with respect to said cathode thereby to render said discharge device non-conductive, a resistor connected across said capacitor to controlthe discharge thereof thereby to time an interval, a second resistor, and means recurrently actuated by vehicles approaching said signal device on a lane having said stop indication for momentarily connecting said second resistor in parallel circuit relation with said capacitor thereby to increase the rate of discharge of said capacitor and incrementally'to decrease the length of said interval.
  • a vehicle actuated traiic signalv control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, electro-responsive signal switching means connected to accord said go indication successively to said lanes, an electron discharge device having an anode, a cathode and a control electrode, means operable upon conduction of said discharge device to actuate said signal switching means to transfer said go indication from a rst to a second lane, a capacitor connected when charged to maintain said control electrode negative with respect to said cathode thereby to render said discharge device nonconductive, a resistor connected across said capacitor to control the discharge thereof thereby to time an interval, a second resistor adapted to be connected in shunt circuit relation with said first resistor, a third resistor normally connected in shunt circuit relation with said first resistor, means recurrently actuated by vehicles approaching said signal device on a lane having said stop indication for momentarily connecting said second resistor in shunt with said first resistor thereby to increase the rate
  • a vehicle actuated traic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting trac lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each of said lanes, means controlled by the vehicle actuated device on a stopped lane for operating said signal switching means to accord said go indication to said stopped lane, means controlled by the vehicle actuated device on a moving lane for rendering each vehicle actuated device on a stopped lane ineffective to operate said signal switching means for an extension interval after each moving lane actuation, timing means controlled by said signal switching means for rendering said means responsive to actuations on a moving lane ineffective after an extension limiting interval, and means responsive to each actuation of the vehicle actuated device on a stopped lane for controlling said timing means to incrementally decrease said extension limiting interval.
  • a vehicle actuated trac signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each of sai-d lanes, second switching means controlled by the vehicle actuated device on a stopped lane for actuating said signal switching means to accord said go indication to that lane, rst timing means for disabling said second switching means, means actuated by the vehicle actuated device ou a stopped lane for controlling said first timing means to maintain said second switching means disabled for at least an initial interval after said go indication is accorded to said lane, means actuated by the vehicle actuated device on a moving lane for controlling said rst timing means to maintain said second switching means disabled for a predetermined extension interval following each moving lane actuation, second timing means controlled by said signal switching means for operating said second switching means independently of said rst timing means after an extension limiting interval,
  • a vehicle actuated trac signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traffic lanes, sinal switching means connected to accord 4said go indication successively to said lanes, vehicle actuated devices on all except one of said lanes, means controlled by a vehicle actuated device on a stopped lane for actuating said signal switching means to accord said go indication to said stopped lane, means controlled by said signal switching means to thereafter return said go indication to said one lane, timing means controlled by said signal switching means and effective upon such return of said go indication to said one lane to render said vehicle actuated devices ineffective to actuate said signal switching means for at least a minimum right of way interval, and additional means controlled by said vehicle actuated devices during said minimum interval to reduce said interval in increments in response to each vehicle approaching the signal device on a stopped lane.
  • a vehicle actuated tratlic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting trac lanes, signal switching means connected to accord said go indication successively to said lanes, vehicle actuated devices on all except one of said lanes, means controlled by the vehicle actuated device on a stopped lane for actuating said signal switching means to accord said go indication to said stopped lane, means responsive to each actuation of the vehicle actuated device on a moving lane for extending the go indication then accorded to that lane, means controlled by said signal switching means for returning said go indication to said one lane, timing means controlled by said signal switching means and effective upon such return of said go indication to said one lane to render said vehicle actuated devices ineltective to actuate said signal switching means for at least a minimum right of way interval, and additional means controlled by said vehicle actuated devices during said minimum interval to reduce sai-d minimum interval in increments in response to each vehicle approaching the signal device on a stopped lane.
  • a vehicle actuated traic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traic lanes, signal switching means connected to accord said go indication successively to said lanes, vehicle actuated devices on all except one of said lanes, means controlled by a vehicle actuated device on a stopped lane for actuating said signal switching means to accord said go indication to said stopped lane, means responsive to each actuation of a vehicle actuated device on a moving lane to extend for a predetermined interval beyond such actuation the go indication then accorded to that lane, timing means operable upon accord of said go indication to a lane to disable said extending means after a limiting time interval, means responsive to each actuation of the vehicle actuated device on a moving lane during said limiting time intelval for incrementally increasing said limiting time interval, means controlled by said signal switching means to return said go indication to said one lane, second timing means controlled by said signal switching means and effective upon such return of said go indication to
  • a vehicle actuated traffic signal control apparatus including a signal device providing stop and go indications for each of ay plurality of intersecting traic lanes, signal switching means connected to accord said go indication successively to said lanes, vehicle actuated devices on all except one of said lanes, electro-responsive means for actuating said signal switching means, an electron discharge device connected when conductive to energize said electro-responsive means, means controlled by a vehicle actuated device on a stopped lane for rendering attivista said discharge device conductive thereby to actuate saidl signal switching means to accord said go indication to said stopped lane, means controlled by said signal switching means for rendering said discharge device conductive thereby to actuate said signal s witching means to return said go indication to said one lane, time element means responsive to each actuation of a vehicle actuated device on a moving lane for maintaining said discharge device non-conductive for a predetermined time interval beyond such actuation thereby to extend the go indication then accorded to that lane, lirst timing means including
  • a vehicle actuated traic signal control apparatus including a signal device providing st op and go'indications for each of a pluralityof intersecting ways lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each of said lanes, second switching means controlled by the vehicle actuated device on a stopped lane for actuating said signal switching means to accord said go indication to that lane, first timing means controlled by the vehicle actuated device on a lane prior to accord of the go indication to that lane for retaining said go indication on that lane for at least an initial interval after accord of said go indication, second timing means controlled by the vehicle actuated device on a moving lane for rendering said second switching means inelective to operate said signal switching means for an extension interval after each moving lane actuation, third timing means controlled by said signal switching means for rendering said second timing means inelective to retain said go indication on a moving lane after an extension limiting interval, third switching means responsive to the vehicle actuated device
  • a vehicle actuated traic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting trac lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each of said lanes, second switching means controlled by the vehicle actuated device on a stopped lane for operating said signal switching means to accord said go indication to that lane, first time element means controlled by the vehicle actuated device on a lane prior to accord of said go indication to that lane for retaining said go indica.- tion on that lane for at least an initial interval after accord of said go indication, second time element means controlled by the vehicle actuated device on a moving lane for rendering said second switching means ineiiective to operate said signal switching means for an extension interval after each moving lane actuation, an electron discharge device connected when conductive to actuate Vsaid signal switching means independently of said second time element means, a capacitor connected to control conduction of said discharge device, a pair of resistors connected
  • a vehicle actuated tratic signal control apparatus including a signal device providing stop and go indications for each of a plurality'of intersecting traiic lanes, ⁇ signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on each of said lanes, second switching means controlled by the vehicle actuated device on a stopped lane for actuating said signal switching means to accord said go indication to that lane, irst timingl means controlled by the vehicle actuated device on a lane prior to accord of said go indication to said lane for'retaining said go indication on said lane for at least an initial interval after accord of said go indication, second timing means controlled by the vehicle actuated'device on a moving lane for rendering said second switching means inetective to actuate said signal switching means for extension interval after each ⁇ moving lane actuation, third timing means controlled by said signal switching means for rendering said second timing means ineffective to extend said go indication after an extension limiting interval, third switching means momentarily responsive to operation of the vehicle
  • a vehicle actuated tratic signal control apparatus including a signal device providing stop and go indications for each of a plurality of intersecting traic lanes, signal switching means connected to accord said go indication successively to said lanes, a vehicle actuated device on at least one of said lanes, second switching means controlled by said vehicle actuated device when said one lane has said stop indication for actuating said signal switching means to accord said go indication to said 'one lane, tirst timing means controlled by said vehicle actuated device on said one lane when said one lane has said stop indication forlpredetermining a subsequent initial right of way interval for said one lane proportional to the number of vehicle actuations on said lane when stopped, second timing means controlled by said vehicle actuated device on said lane when Vsaid one lane has said go indication for rendering said rst switching means ineffective to remove said go indication for at least a predetermined extension interval after each moving lane vehicle actuation, third timing means for actuating said signaly switching means to remove said go indication from said one

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FR1087498D FR1087498A (fr) 1952-08-26 1953-08-25 Système de commande de signaux pour la circulation, actionné par les véhicules

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US3106695A (en) * 1958-05-14 1963-10-08 Lab For Electronics Inc Traffic control apparatus
US3128446A (en) * 1957-10-03 1964-04-07 Lab For Electronics Inc Traffic actuated control system
US3221299A (en) * 1960-08-11 1965-11-30 Lab For Electronics Inc Traffic control and selector apparatus
US3241108A (en) * 1960-09-12 1966-03-15 Lab For Electronics Inc Traffic actuated control system
US3241103A (en) * 1960-09-12 1966-03-15 Lab For Electronics Inc Traffic actuated control apparatus
US3241109A (en) * 1961-08-18 1966-03-15 Lab For Electronics Inc Traffic actuated control system
US3258745A (en) * 1962-04-19 1966-06-28 Traffic responsive vehicle traffic control system
US3258744A (en) * 1963-02-20 1966-06-28 Vehicle traffic control system
US3333240A (en) * 1964-04-16 1967-07-25 Bunker Ramo Intersection traffic controller
US4433324A (en) * 1975-03-21 1984-02-21 Francis Guillot Device to promote the movement of buses by allocation of priority of crossing of an intersection controlled by traffic lights

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US2925583A (en) * 1956-02-13 1960-02-16 Crouse Hinds Co Control apparatus responsive to traffic density
US3128446A (en) * 1957-10-03 1964-04-07 Lab For Electronics Inc Traffic actuated control system
US3106695A (en) * 1958-05-14 1963-10-08 Lab For Electronics Inc Traffic control apparatus
US3221299A (en) * 1960-08-11 1965-11-30 Lab For Electronics Inc Traffic control and selector apparatus
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US3333240A (en) * 1964-04-16 1967-07-25 Bunker Ramo Intersection traffic controller
US4433324A (en) * 1975-03-21 1984-02-21 Francis Guillot Device to promote the movement of buses by allocation of priority of crossing of an intersection controlled by traffic lights

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FR1087498A (fr) 1955-02-24

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