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Publication numberUS3255433 A
Publication typeGrant
Publication dateJun 7, 1966
Filing dateJan 3, 1962
Priority dateJan 3, 1962
Publication numberUS 3255433 A, US 3255433A, US-A-3255433, US3255433 A, US3255433A
InventorsLesher John C
Original AssigneeRad O Lite Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Traffic light controller
US 3255433 A
Images(5)
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Description  (OCR text may contain errors)

J. C. LESHER TRAFFIC LIGHT CONTROLLER,

June 7, 1966 5 Sheets-Sheet 1 Filed Jan. 5, 1962 June 7, 1966 J. c. LEsHER TRAFFIC LIGHT CONTROLLER 5 Sheets-Sheet 2 Filed Jan. 3. 1962 INVENTOR ATTORNEYS June 7, 1966 J. c. LESHER TRAFFIC LIGHT CONTROLLER 5 Sheets-Sheet 5 Filed Jan. 5. 1962 mwN INVENTOR Jeun C. LEsHr-:la

.WAN

ATTORNEYS June 7, 1966 J. c. Ll-:sHER 3,255,433

TRAFFIC LIGHT CONTROLLER Filed Jan. I5, 1962 5 Sheets-Sheet 4 ATTORNEYS June 7, 1966 J. c. LESHER TRAFFIC LIGHT CONTROLLER 5 Sheets-Sheet 5 F'led Jan. 3, 1962 INVENTOR oHuC. LESHEL ATTORNEYS NWN.

m .UMH

United States Patent O 3,255,433 TRAFFIC LIGHT CONTROLLER John C. Lesher, Erie, Pa., assigner to Rad-Ombre, lne., Erie, Pa., a corporation of Pennsylvania Filed Jan. 3, 1962, Ser. No. 164,647 4 Claims. (Cl. 34m- 37) The present invention rela-tes to traiiic light control systems and rnore particularly to an electronic traffic signal controller which is completely compatible for use with a plurality of dille-rent types of auxiliary traflic and pedestrian control equipment.

It is an object of the present invention to provide an electronic trailic signal controller which employs a small num-ber of rugged, long-lived elements and which is simple and readily serviceable.

It is another object of the present invention to provide an electronic traffic signal controller which provides independent adjustment of the lengths of the relative timings of the various red, green and amber lights.

It is still another object of the present invention to provide an electronic traflic signal controller employing a basic timing circuit inclu-ding separate controls for the timing of the different sets of red and green signals.

It is yet another object of the present invention to provide an electronic traffic signal controller which is compatible with and easily connected with a large number of auxiliary traffic and pedestrian control signal arrangements. 4

It 4is another object of the present invention to provide an electronic traiiic signal controller employing a basic timing circuit which may be rendered inoperative and/or retimed by auxiliary traiic and pedestrian control apparatus connected to the basic control unit.

Another object of the present invention is to provide an electronic trafc signal controller to which a Walk- Dont Walk control unit may readily be added by the simple expedient of connecting a single cable between the basic and the auxiliary units.

It is yet another object of the present invention to` provide a trafc-actuated control unit for use with an electronic traiiic signal controller which unit may be adapted to the basic control unit simply by .connecting a cable therebetween.

It is another object of the present invention to provide a traine-actuated control unit for utilization in conjunction With an electronic trac signal controller, which unit has a circuit for remembering that a vehicle has actuated a traffic detector after t-he initiation of a cycle for returning control ofthe trafc signals to the basic controller, so that subsequently, and Without further operation of the detector, the control of the signals is again returned to the trahie-actuated unit.

It is still another object of the present invention to provide a traffic-actuated control -unit for utilization in conjunction with a basic electronic traflic signal controller in which the interval during which the tralicactuated unit maintains control over the traffic signals is a function of the number of vehicles detected on a cross street up to a predetermined maximum interval.

It is still another object of the present invention to provide a liashe-r unit which may be employed in conjunction with a basic electronic traffic signal controller, the flasher unit causing a blinking amber signal to appear along a main street and a blinking red signal to appear along a cross street.

It is yet another object of the present invention to provide a flasher control unit which is completely compatible with an electronic traffic signal controller and which may be connected thereto by a single cable, which Mice flasher unit causes a blinking display of light to be rnaintained during olf-hour traflic conditions.

Still a furthe-r object of the present invention 1s to provide an emergency traiiic light control unit which is completely compatible with the basic electronic traffic signal controller, and whiohcauses green and/or red signals to -be displayed under the temporary control oi an emergency vehicle having thereon a prescribed transmitting unit for generating signals detected by the aforesaid eme-rgency control unit.

It is yet another object of the present invention to provide an emergency trafc control unit which is completely compatible with and may be directly connected to an electronic traffic signal controller by means of a single cable connection. v

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIGURE l is an electrical schematic' diagram of the basic electronic tralic signal controllerof the present invention;

FIGURE 2V is an electronic schematic diagram of a WalkDc-nt Walk signal unit which is compatible with the control-1er of FIGURE l;

FIGURE 3 is an electrical schematic diag-ram of a traine-actuated control unit whichV is compatible with the controller of FIGURE l;

FIGURE 4 is an electrical schema-tic diagram of a ilasher control unit which is compatible with the controller of FIGURE 1; and

FIGURE 5 is an electrical schematic diagram of an emergency control unit which is compatible with the system illustrated in FIGURE 1.

Basic #ao control circuit Referring specica-lly to FIGURE l off the accompanying drawings, there is illustrated a schematic electrical circuit diagram of the basic trailic light controller of the present invention. The diagram is arranged so that, where practical, the various terminals to which auxiliary equipment may be attached extend beyond the out-line of the several lead lines of the circuit. The auxiliary equipment relates to maintaining red sign-als in all direct-ions so that pedestrians may walk, control of oihouf flashing of the lights, semi-traiicactuated and fully traine-actuated control for -iiow of vehicles from cross streets, control of the lights by emergency vehicles, an-d various other attachments which are completely compatible with the controller of this ligure.

The circuit is illustrated in the condition in which green lights 1, arrayed along a main street, and red lights 2, arrayed along a cross street, are illuminated. The lights 1 and 2 are connected to `a common bus 3 which, for purposes of explanation, will hereafter be referred to as ground or common. The energizing voltage for the green lights 1 is applied to a lead 4, which is connected to the lights via a terminal 5, while the energizing voltage .for the red lights 2 is applied to a lead 6. The lead 4 is connected to a fixed contact 7 of a relay 8 having a rst movable contact 9. When the relay 8 is energized, the contact 9 engages the fixed contact 7, but when the relay 8 is de-energized, contact 9 engages the second lixed contact 11, as illustrated. The relay 8 is provided with a second set of stationary contacts 12 and 13 which are alternately engaged by a movable contact 14, the movable contact 14 engaging the lxed contact 12 when the relay 8 is energized. The movable contact 9 is connected via a high voltage bus 16 to a high voltage, A.C. input terminal 17, and thus it is seen that high voltage is applied to the lead 4 via the high voltage bus 16 and the contacts 7 and 9 to complete the energizing circuit for the main street green lights 1.

The lead 6, on which is to be developed the high voltage Afor illuminating lamps 2, is connected to a terminal 18 which, in turn, is connected to a terminal 19 via a jumper 20. This jumper may be removed when certain auxiliary equipment is to be added and this will be discussed in detail subsequently. The terminal 19 is connected via a lead 21 to a further lead 22, which is connected to a movable contact 23 of a relay 24 having fixed contacts 26 and 27 cooperating with the movable contact 23.` The relay 24 is deenergized and, in this condition, the movable contact 23 is in engagement with contact 26. The relay 24 is provided with a further set of fixed contacts 28 and 29 adapted to be alternatively engaged by a movable contact 31 which, when the relay 24 is deenergized, engages the contact 28.

The contact 26 of the relay 24 is connected via a lead 32 to' a fixed contact 33 of a relay 34, which is deenergized during the interval through which the main street green lights 1 are on. The relay 34 has a movable contact 36, which is in engagement with the fixed contact 33 when the relay is deenergized, and which engages a further tixed contact 37 when the relay is energized. Since the relay 34 is deenergized, the lead 32 is connected via contacts 33 and 36 of the relay over a lead 38 to a second fixed contact 28 of the relay 24. The contact 28 is engaged by the movable contact 31 of the relay 24, which is connected to the high voltage bus 16. Thus, the cross street red lamps 2 are illuminated as a result of having a high voltage applied thereto via lead 6, terminal 18, jumper 20, terminal 19, lead 21, lead 22, contacts 23, 26, lead 32, contacts 33, 36, lead 38 and contacts 28 and 31 to the high voltage bus 16.

The relay 8 is now energized by an energizing circuit through a diode 39 and resistor 41 connected between the lead 21 and one end of the winding of the relay, as illustrated in FIGURE l. The other end of the winding of the relay 8, also as illustrated in FIGURE 1, is returned to common or ground via a lead 42, engaged fixed contact 43 and movable contact 46 of latching relay 44 and a lead 47 returned to a terminal 48, to which the system common or ground is connected. It will be noted that the common terminal 48, which is connected to ground, is also connected via a jumper 49, which is illustrated by dotted lines, to a lead 51, which is connected to the common terminal 52 of the system.

l T imng means The interval during which the traffic light controller is maintained in the condition described immediately above, and illustrated in FIGURE 1, is determined by a timing circuit generally designated by the reference numeral 53. This circuit includes a timing capacitor 54 connected in the grid circuit of a parallel-connected, dual triode 56. The lower side of the capacitor 54, which is designated by a plus sign, is returned via a lead 57 to the common voltage or grounded bus 51, whereas the upper side of the capacitor, as illustrated by the negative sign, is connected via a lead 58 to a junction 59. The junction 59 is. connected via a resistor 61 and a variable resistor 62,-connected in series, to a further lead 63. A variable resistor 64 is connected in parallel with resistor 62 and is employed to control the time constant of the discharge circuit of the capacitor 54. The variable resistor 64 is the main street green light control in that it determines the interval during which the main st-reet green lights 1 are on, as will be apparent from the continued discussion. The lead 63 is connected to a fixed contact 66 of a latching relay 67 having a first movable contact 68 which, in the position illustrated, engages the contact 66 and, when the relay 67 is energized, is moved into engagementwith a further fixed contact 69. The contact 6 8 is connected to the lead 47, towhich the common return lead 51 is also connected via the jumper 49. Therefore, a series circuit 4 is established including the capacitor 54 and the resistors 61 and 62-64.

The capacitor 54, as will be explained subsequently, initially has a negative voltage applied thereto rendering the tube 56 nonconductive. After an interval, as determined by the value of the resistors 61 and 62 and the setting of the variable resistor 64, the capacitor 54 becomes suiciently discharged to permit the tube 56 to conduct. Upon conducting, the tube 56 energizes a relay 71 having a first set of contacts including a fixed contact 72 and a movable contact 73-and a second set of contacts comprised by the movable contact 74 and a fixed contact 7S. When the relay 71 is deenergized, the contacts assume the positions illustrated whereas when the relay is'energized, the movable contacts 73 and 74 engage the fixed contacts 72 and 75, respectively. The movable contact 73 is connected via a jumper 76 to the high voltage lead 16 and thus, when the movable contact 73 engages the fixed contact 72, it applies a voltage viav a lead 77, resistor 78 and diode 79 to the lead 58, thereby negatively charging the capacitor 54, the diode 79 being poled so that negative voltage swings are applied to the capacitor from the A.C. high voltage lead 16. Charging of capacitor 54 thereafter renders the tube 56 again nonconductive.

The high voltage operating potential of the tube 56 is derived from the A.C. high voltage lead 16 via jumper 76 and a lead S1 to 4the lower end of the winding 71 as illustrated in FIGURE l, a capacitor 82 maintaining the relay 71 energized during negative swings of the A.C. high voltage. The lead 31 is further connected to a terminal 85 and through a resistor 83 and a diode 84 -to the movable contact 74. Thus, a pulsating A.C. is developed on the movable contact 74, so that when it engages its associated fixed contact 75, upon energization of the relay 71, a pulsating voltage is applied to a Ilead 86, which is connected to a fixed contact 87 of the latching relay 67. During this instant of operation, the fixed contact 87 is engaged by a movable contact 88 of the relay, which is connected via a lead 89 to the one end of the winding of the relay, as illustrated in FIGURE l. The other end of the winding of the latching relay 67 is connected via a lead 91, contacts 12 and 14 of the relay 8, and a lead 92 and a further lead 93, to a terminal 94, which is connected to one side of' the main street red lamps 96, which are connected in parallel. The other sides of the main street red lamps 96 are connected to the ground return lead 3. Thus, the winding of the latching relay 67 is returned to ground lthrough the main street red lights 96. Since these lights are not illuminated at this moment, their resistance is quite low and sufficient current is permitted to flow from the lead 89 through the winding of the relay 67 to the ground return lead 3 to energize the relay.

Upon energization of the relay 67, the movable contact 68 is brought into engagement with the fixed contact 69 and the movable contact 88 4is brought into engagement with an additional fixed contact 97 of the relay 67. The movablecontacts of the latching relays 44 and 67 are interconnected by a mechanical link 100 so that upon energization of the relay 67, the movable contact 46 of the relay 44 engages fixed contact 98 and an additional movable contact 99 of the relay 44 becomes disengaged from a fixed contact 101, and moves into engagement with a fixed contact 102. The interconnected latching relays 44 land 67 and the movable contacts thereof remain in the last stated positions even after the removal of the yhigh voltage from the relay 67, which occurs when the tube 56 is again rendered nonconductive.

Transfer 0f right of way The apparatus is now primed for a new condition in which the main street red lights 96 and the cross street green lights 103 are illuminated. In changing from the main street green lights on to the main street red lights on, it is first desired, in conformance with usual practice, to light the main street amber lights 104, and this is ac` Complished by the deenergizatiou of the relay 8 and energization of a further relay 106, having stationary contacts 107 and 108 and a movable contact 109, which latter is in engagement with the contact 107 when the relay 106 is energized. One end of the winding of the relay 106 is connected via a lead 111 to the common return 51 and the other end of the winding is connected, under the conditions illustrated in FIGURE l, via a resistor 112, diode 113 and resistor 114 to high voltage lead 4.

When the relay 67 is energized, the ground return lead for latching relay 8 is broken at contacts 43, 46 of'relay 44 and relay 8 is deenergized. Movable contact 14 moves out of engagement with the xed contact 12 and engages the contact 13 while the movable Contact 9 moves out of engagement with the fixed contact 7 and engages the Contact 11. High voltage is now applied from the high voltage lead 16 and through movable contact 9 to the xed contact 11 of the relay 8 and via a lead 116 to movable contact 109 of relay 106. Movement of the movable contact 9 out of engagement with the fixed contact 7 breaks the energizing circuit to the relay 106, but a capacitor 118, which is connected in parallel therewith maintains the relay 106 energized for a length of time determined by resistors 110 and 120, which are connected in series between the lower end of the capacitor 118 and the common lead 51, which is also connected via the leads 146 and 111 to the upper end of capacitor 118. A variable resistor 125 is connected in parallel with resistor 120 and determines the discharge rate of capacitor 118 and therefore the delay in deenergization of relay 106. During the interval between deenergization of relays 8 and 106 high voltage is applied through contacts 107 and 109 of relay 106 and lead 117, and terminal 115 to main street amber lights 104. Alfter the relay 106 times out, the contacts 107 and 109 open deenergizing the amber lights 104. Contact 109 now engages fixed contact 108' and applies high voltage via lead 119 and contacts 13 and 14 to lead 92.

High voltage is thus applied to the lead 93, which is connected to the main street red lights 96. Application of high voltage to the lead 92 also energizes the relay 24 via a resistor 121 and diode 122, the ground return of the relay 24 now being completed via a lead connected through the contacts 68 and 69 of the latching relay 67 to the common bus 47. Since the cross street red lights 2 are energized through both sets of contacts of the relay 24 when it is deenergized, the red lights 2 on the cross street are not deenergized until after the completion or termination of illumination of the amber lights 104 on the main street.

Upon the energization of the relay 24, the movable contact 23 is moved out of engagement with the iixed contact 26 and is moved into engagement with the fixed contact 27. Concurrently, the movable contact 31 is moved out of engagement with the fixed contact 28 and is moved into engagement with the lixed contact 29. The contact 29 is connected via a lead 124 to a terminal 126, which is connected to one side of the cross street green lights 103, thus completing the energizing circuit for these lights. Application of high voltage to the lead 124 also applies a voltage to a lead 127, connected therewith, which is connected through a resistor 128 and diode 129 to the upper end of the coil of the relay 34. Energization of the wind ing of the relay 34 now causes the movable contact 36 to become disengaged from the tixed contact 33 and become engaged with a iixed contact 37. The contact 37 is connected via a lead 131 to the terminal 132, which is connected to one side of the cross street amber lights 133, conditioning this circuit for future operation. However, since the lead 38 is connected to theiixed contact 28 of the relay 24, no voltage is now applied to this circuit, the movable contact 31 now being in engagement with the fixed contact 29.

When the latching relay 67 was energized at the beginning of this interval of operation, the timing resistors 61 and 62-64 for the capacitor 54 were removed from the circuit, due to opening of contacts 66y and 68 but an additional set of resistors 134, 136 and adjustable resistor 137 were connected in the circuit via a lead 138 and contacts 46 and 98 of the latching relay 44. The capacitor 54 now discharges through these resistors until the voltage thereacross permits the tube 56 to again become conductive. The individual controls provided by the first group of resistors 61 and 62-64 and the second group of resistors 134, 136, 137 permits independent adjustment of the periods of red and green on the intersecting streets.

Energization of the relay 71 again causes the contacts 72 and 73 to become engaged and apply a negative bias to the capacitor 54 to again stop conduction of the tube. The relay 71 upon being energized, also closes contacts 74 and 75 which now apply a high voltage via lead 86, and contacts 102 and 99 of the latching relay 44, to a lead 139, which energizes the rel-ay 44 and shifts-the contacts associated with the relays 44 and 67 back to the positions illustrated in FIGURE 1. The relay 24 is now 'deenergized and causes a high voltage to be applied through contacts 36 and 37 of the relay 24 to the lead 131, thereby energizing the cross street amber lights 133. After the relay 34 times out, themovable contact 36 returns to the position illustrated in FIGURE 1 and energizes the relay 8, now causing its contacts to lassume the position illustrated in FIGURE l, thus energizing the main street green lights 1. The cross street red lights 2 are now also energized through the contacts 31 and 28 of the relay 24 and contacts 36 and 33 of the relay 34.

The timing of the relay 34 is determined by a capacitor 141, which is connected in parallel with the winding of the relay, and resistors 142, 143 and an adjustable resistor 144, which is connected in parallel with resistor 143. These resistors are returned via a lead 146 to the common return lead 51, to which one side of the capacitor 141 is connected via a lead 147.v Thus', the discharge of the capacitor 141 is determined by the resistors 142, 143 and 144, which are connected in parallel therewith. A resistor 148 is connected between the other side of the capacitor 141 and one end of the Winding 34, and of course yalso assists in determining this timing interval since the rate of discharge of the capacitor 141 through the winding of the relay 34 is determined by the value of this resistor. l

A complete cycle of operation of the apparatus has n-ow been described and it will be seen that the controller provides for independent control of the timingof the red and green intervals on the main and cross streets and also independent timing of the amber periods on the main and cross streets.

External control As previously indicated, the apparatus is specifically adapted for external control and a discussion of this feature will now be undertaken. It will be noted that the lead 89, which is connected to one side of the winding of the latching relay 67, is also connected to a terminal 149, while the lead 139, which is connected to one side of the winding of the latching relay 44, is connected to a tenminal 1 51. The latching relays 44 and 67 may be controlled by the application to terminals 1511 and 149, respectively, of external sources of voltage and, if the timing circuit associated with the tim-er control 53, that is the capacitor 54 and tube 56 and the various resistors, is rendered inoperative, control-of the `apparatus may be eliected completely from external sources. Two methods of preventing operation of the timing circuit are provided and are employed for different purposes, as will be described subsequently. First, it will be noted that the lead 58, which is connected to the grid of the tube 56, is connected through a resistor 152 to a terminal 153. If now a constant negative voltage is applied to the terminal 153, the tube 56 is held nonconductive for the interval during which this negative voltage is applied. Thus, if it is desired to control the latching relays 44 and 67 from an external circuit, a negative voltage may be applied to the terminal 53 rendering the entire t-iming circuit inoperative. Also, it will be noted that the jumper 76 is employed between the high voltage lead 16 and the movable contact 73 of the relay 71. 1f the jumper 76 is removed and a control circuit placed between leads 16 and the movable contact 73, the high voltage for operating the relay and thus for internally controlling operation of the latching relays 44 and 67 may be inserted.

Pedestrian signals Referring now speciiically to FIGURE 2 of the accompanying drawings, there is here illustrated an attachment for use with the controller illustrated in FIGURE 1 which provides for Walk and Dont Walk signals in conjunction with the tratiic, lights. During Walk conditions, all lamps become red to stop the ow of all traflic and Walk signsl are displayed at all corners to permit pedestnians to cross the streets. In order to effect this operation, the jumper 49 in FIGURE 1 is removed and the terminal 48 is connected to a corresponding terminal 48 in FIGURE 2. Also a terminal 18 in FIGURE 2 is connected to the terminal 18 in FIGURE 1, as are terminals 17, 52, 115 and 153 of FIGURE 2 connected to corresponding terminals in FIGURE 1.

It will be seen that, by removal of jumper 49, the ground return is removed from the terminal 48, which is connected via a lead 47 to the movable contact 68 of the relay 67. The ground return is now effective through the contacts of the various relays in FIGURE 2. Also, the terminal 153 of FIGURES 1 and 2 is connected to apply a negative voltage to the grid of tube 56 to disable the timing circuit 53 during selected intervals.

The operation of the circuit of FIGURE 2 is dependent upon predetermined conditions occurring in the apparatus of FIGURE 1, these conditions being sensed through connections to the terminals 18 and 115 of FIGURE 1. Specifically, when the cross street red lights 2 a're illuminated, a relay 154 is primed by having high voltage applied to one end of its winding, and when the main street amber lights 104 are illuminated, a relay 156 is deenergized. The relay 156 is normally maintained energized by a parallel--connected, dual triode 157, which is maintained normally conducting by having its grids 158 connected through a resistor 159, normally discharged capacitor 161, and lead 162 to further leads 163, 164 and 166 and to th-e common terminal 52. When the capacitor 161 is discharged, the grids and cathodes of the tube 157 are respectively at the same potential and the tube isconductive. The relay 156 has with a movable contact 167 and fixed contacts 168 and 169. When the relay is energized, the movable contact 167 engages the stationary contact 168 and grounds a lead 171, which is connected to contact 168, since the movable contact 167 is connected to the grounded lead 163 via a further lead 172. When the main street amber lights 104 are illuminated, the alternating high voltage applied thereto is applied via terminal 11S to a series circuit comprising a resistor 173, diode 174 and resistor 175 to a lead 176 connected to the one side ofA the capactor 161. The diode 174 is poled so that the capacitor 161 is charged negatively by the A.C. voltage applied to the terminal 115 and therefore cuts otl` the tube 157, deenergizing the relay 156. After termination of illumination of the main street amber lights 104, the voltage is removed from the terminal 115 and the capacitor 161y discharges through an adjustable resistor circuit, comprising a resistor 177 and adjustable resistor 178 connected in series with one another and in parallel with the capacitor 16-1. Thus, the interval during which the'tube 157 is deenergized is equal to the duration of the main street amber lights 104, plus a variable time, as determined by the value of the resistor 177 and the adjusted value of the resistor 178. The total interval should be adjusted to allow at least the average person tocross the streets on a Walk signal.

As previously indicated, one end of the lead 171 is connected to ground via contacts 167 and 168 of the relay 156, undernormal operating conditions, and the other end of the lead 171 is connected through a movable contact 179 and xed contact 181 of the relay 182 to a further lead y183. The lead 133 is connected through normally closed contacts 184 and 186 of the relay 154 to the terminal 48, which, as stated, in the common ground terminal, and is also connected to the lead 47 of FIGURE 1. Thus, when the relays `154'and 182 are deenergized and the relay 156 is energized, the lead 47 ot FIGURE 1 is returned to `the common terminal 52, via the circuitry of FIGURE 2.

One end of the winding of the relay 182 is returned through a diode 187 and resistor 188 to a lead 189, which is connected through contacts 191 and 192 of a switch 190 to the high voltage terminal 17. The switch 190 serves as a manual control to place the Walk control in operation, when in the position illustrated, or to take the Walk control out of operation if the switch is thrown to the off position, as indicated in FIGURE 2. The other end of the wind-ing 182 is connected through a diode 194 to a lead 195, which is connected to the 1ixed g contact 169 of the relay 156. Since the tixed contact 159 signal 201.

is normally not engaged by the movable contact 167, the ground return circuit of the relay 182 is not completed and the relay therefore remains deenergized. Also, it will be noted that one end of the winding 154 is connected via a lead 196 to the lead 195 and therefore the ground return circuit of the relay 154 is also incomplete, so long as the relay 156 is energized.

Transfer of right of way At the end of cycle of the basic traffic light controller as illustrated in FIGURE l, that is, with the cross street red lights 2 andthe main street green lights 1 illuminated, the latching relay 67 is energized, thereby deenergizing the relay 8 and causing the high voltage to be applied to the amber signal 104 on the main street and `at the same time turning 01T the main street green l-ights 1. The cross street red lights 2 are still illuminated through high voltage being applied to both of the terminals 18 and 115. The. voltage applied to the terminal deenergizes Ithe tube 157 and relay 156 breaking the ground return lead from the terminal 48 to the terminal 52, and thereby insuring that both relays 8 and 24 in FIG- URE 1 remain deenergized. This condition causes red lights 2 and 96 to be displayed on the cross street and the main street, respectively. The red light 96 on the main street are illuminated after termination of illuminat-ion of the amber lights 104 on the main street, this latter 'being -under control of the relay 106. As soon as the relay 106 is deenergized, due to discharge of its capacitor 118, a voltage is applied to the main street red lights 96.

Termination of energization of the relay 156 closed the ground return circuits for the relays 154 and 182 through contacts 167 and 169, thereby breaking the connection between terminals 48 and 115 at two further locations, the contacts of these latter two relays. The relay 154 has an additional set of contacts including movable contact 197 and fixed contacts 198 and 199. The movable contact 197 is connected to the high voltage terminal l17 via lead 189, contacts 191 and 192 of switch 190 and when the relay 154 is deenergized, energizes a Dont Walk However, when the relay 154 is energized, the fixed contact 197 engages contact 198 and energizes Walk signal 202. At the same time, high voltage is applied from the fixed contact 198 through a resister 203 and diode 204 to -a lead 206, which is connected vto the terminal 153. The diode 204 is poled such that a negative pulsating voltage is applied to the terminal 153 and through resistor 152 to lead 58 in FIGURE 1, thereby lbiasing the tube 56 to cut-ott for an interval dependent upon 'the duration of the Walk signal, and for a period thereafter as determined :by the timing circuit associated with the capacitor 54.

At a predetermined time interval after termination of the main street amber lights 104', the capacitor 161 discharges through resistors 177 and 178 and the turbe 157 is again rendered conductive energizing the relay 156.

Energization of the relay 156 removes the energizing voltage from rel-ays 154 and v132. The relay 154 is deenergized almost immediately, a Dont Walk7 signal 201 is displayed, and the negative voltage is removed from the lead 206 permitting the capacitor 54 to start to discharge. A capacitor 207, which is connected in parallel with the Iwinding of the relay 182, maintains this relay energized for an interval determined by resistor 208 and variable reistor 209, which is connected in parallel with the capacitor 207. The function of this timing circuit is to prevent the connection between terminals 4S and 52 from being made for a predetermined interval after the Dont Walk signal 201 is illuminated, in order to permit people to clear the street. After this interval, which may be several seconds, Ithe relay 1&2 times out and the circuit from terminal 48 to terminal 52 is completed. Since the latching relay 67 had previously closed its contacts 68 and 69, the energizing circuit for the relay 24 is completed and the apparatus returns to a normal cycle, in which the main street red lamps 96 are maintained illuminated and the cross street greenlamps 103 are illuminated. After the capacitor 54 has discharged, the circuit is switched back to the condition illustrated in :FIGURE 1 and normal cycling continues until the next display of the main street amber lights 104, at which time the Walk signal circuit temporarily takes over control and then initiates a new cycle.

Completing the description of the apparatus illustrated in FIGURE 2, it may be desirable to provide a remotely controlled cut-off for this circuit and this is effected tby a relay 211-Which is adapted to -be energized remotely via a terminal 212. This terminal 212 is connected to one side of Ithe winding of the relay i211 through a resistor213 and a diode 214; the other .side of the winding is connected to the common 'bus 164. A capacitor 215 is shunted across the winding of the relay.

When the relay 211 is to be employed, the switch 190 is placed in the ofi?, or down, position and the high voltage circuit between terminals 17 and lead 189 is completed through contacts 218 and 219 of the relay, while the contacts 220 and .221 break a ground return circuit from the grids 158 ofthe tube 157 through a resistor 216 overa lead 217. With the switch 190 in'the down position, the xed contact 221 of the relay 211 is connected via a lead 222 kand a set of contacts 223 and 224 of the switch 190 to the common :bus 164, thereby applying ground potential to the grid of the tube 157 and insuring that the tube is energized. Upon energization of the relay 211, the ground return lead for the grids 158 of .the tube 157 is broken and the tube is rendered nonconductive. Concurrently, the contacts 21S and l219 close and high voltage is applied to the lead 189, so that the Walk circuit is now rendered operative. Upon removal of voltage from the terminal 212, the relay 211 is deenergized and the circuit returns to the condition illustrated, at which time the Walk circuit is d-isconnected from the apparatus. This may be desirable during off hours, when the pedestrian traffic is light and the Walk signals are not required.

Side street trac actuation Referring now specifically to FGURE 3 of the accompanying drawings, there is here illustrated another auxiliary unit, which may be attached to the controller illustrated in FIGURE 1. The apparatus of FIGURE 3 comprises a trafiic-actuated controller and is to Ibe employed in those situations where the cross street traiic is normally very light and it is desired to maintain the main street green lights 1 illuminated at all times, except when traffic is detected along the cross street. The circuit includes two main features: The first is that, if a vehicle is detected while t-he lights are in the process of changing from a cross street green to a main street green; for instance, the cross street amber is illuminated, the circuit will remember that a vehicle was detected and, after a predeterminedv interval will switch back to a cross street green. This type of ope-ration eliminates the necessity of backing up the vehicle to again trip a tratiic detector 225, since these detectors are normally placed a distance from the corner which is greater than the length of a car. A second feature is that the time that the cross street lgreen lights 103 are maintained illuminated up to a predetermined limit, is determined by the num-ber of vehicles detected.

The interconnection of the circuit of FIGURE 3 with the circuit of FIGURE 1 is again indicated by the use of the corresponding terminal numbers in thetwo gures. Assuming that the controller circuit is in the condition illustrated in FiGURE l; that is, the green lights 1 are illuminated along the main street and the red lights 2 along the cross street. If vehicle comes along the cross street, it trips or actuates the cross street detector 225 connected to the common return terminal 5-2 on one side, and connected on its other side by a lead 2126 tothe coils of a pair of relays 228 and 2129, the latter being a latching relay. The coil of the relay 228 is shunted by a capacitor 239 and the coil of the latching relay 229 by a capacitor 231. Connection of the lead 226 to ground energizes the latching relay 229 since the other end of the winding is returned .through a diode 235, resistor 236, fixed contact 233 and its movable Contact 232 to the high voltage terminal 17. Upon energization of relay 229, its movable r contact 232 engages a further fixed conta-ct 234 applying high voltage to a junction 239 through a resistor 237 and diode 233. The junction 239 is connected through a capacitor 240 and resistor 241 which are connected in parallel, by a lead 242 to the` terminal 149. Immediately prior to application of voltage to the junction 239, the capacitor 233 had been completely discharged through the resistor 241, and, upon application of a voltage to the v junction 239 there is a rush of current through the capacitor 240 and therefore through the winding of the latching relay 67, energizing this latching relay and causing its contacts to assume a position opposite to those illustrated in FIGURE 1. The rush of .current provided by this operation is suiicient to completely charge the capa-citor 240 so that further tripping of the street detector 225 has no effect upon the latching relay 67, until almost complete discharge of capacitor 240, which requires a considerable period as will be described subsequently.

Energization of the latching -relay 67 causes the controller to perform in its conventional manner and the apparatus switches from main street green lights 1 and cross street red lights 2 on, to main street red lights 96 and cross street green lights 103 on. Operation of the latching relay 229 also causes -sepa-ration of a further set of contacts including a movable contact 245 and stationary contact '244. The contact 244 is connected through a diode 247 and resistor 24.8 over a lead to the terminal 5 of FIGURE 1, while the movable contact 245 is connected through a resistor 250 over a lea-d 2511 to the terminal 153 of the FIGURE 1. The terminal 5 of FIG- URE l is -connected through a resistor 253 and a capacitor 254, in parallel, and over a lead 255 to a further fixed Contact 246 of the latching relay 229. Thus, since the terminal 5 is connected in the circuit of the main street green light, it is normally energized with an A.C. high voltage. The rectifier 247 provides'a pulsating negative voltage on the terminal 153, which biases the tube 56 to cut-off and therefore prevents normal cycling of the apparatus. However, when the latching relay 229 is energized and the contacts 244 and 245 are separated,

the negative voltage is removed from the terminal 153 and the capacitor 54 is permitted to discharge, so thatthe cross street green lights 103 are permitted to remain illuminated only for a predetermined interval and thereafter the cross street lights are switched back to red.

`Returning to the operation of the apparatus of FIG- URE 3, during the interval of operation when the relay 229 was energized, t-he positions of the contacts on a further latching relay 256 were also altered, since the movable contacts of these two relays are mechanically interconnected by a link 257. Movable fixed contact 258 of the relay 256 normally engages a disconnected xed contact 258 but, upon energization of the latching relay 229, the movable contact engages a second fixed contact 260. The movable contacts 259 is connected over a conductor 261 to the common return terminal 52, while the fixed contact 260 is connected via a lead 262 to one side of the winding of the relay 256. The other side of the coil of the relay 243 in FIGURE 3 is connecte-d through a diode 263 and resistor 264, which are connected in series, and over a lead 265 to the terminal 115. Thus, in the cycle initiated by tripping of the cross street detector 225, the main street indication rst switches from the green lights 1 to the amber lights 104 on and, at that time, the latching relay 256 is energized and `returns its movable contacts and the movable contacts of the latching relays 229 to the positions illustrated in FIGURE 3. A negative bias is not applied to the terminal 153 at this time, since the cross street green lights 103 are now illuminated and therefore no voltage is applied to the terminal 5. If no further tratiic comes along the cross street and trips the detector 225, Ythen the control system of FIGURE l will go through a normal cycle,vas determined by the timing circuit 53 and return the apparatus to the main street green lights 1 on, at which time the negative bias is again applied to the tube 56 and the main street green lights are maintained on, until the next unit of traic is detected along the cross street.

As previously indicated, the circuit of FIGURE 3 has a memory feature in that if after termination of the main street amber lights 104 and removal of voltage from the terminal 115, a second vehicle comes along and trips the detector 225, the latching relay 229 is again energized.

Two types of operation are now possible: If the cross street green lights i103 are still illuminated, one type of operation is effected and this will be explained subsequently: If the cross street amber is lit at this time, another type of operation occurs, as explained immediately below: p

Energization of the latching relay 224 does not affect the latching relay 67 since the capacitor 240 is insutiiciently discharged. However, energization of latching relay 229 does remove the negative bias from the terminal 153 and the apparatus of FIGURE l continues to cycle under control of the timing circuit 53. Therefore, the apparatus of FIGURE l will cycle through a main street green lights on, and then revert to a main street amber lights 104 on followed `by a main st-reet red lights 96 on, and a cross street green lights 103 on. During the interval in which t-he main street green lights 1 are illuminated, the return circuit for the latching relay 67 in FIGURE l is open at the contacts 12 and 14 of the relay 8, so that the capacitor 240 discharges through the resistor 234.

The time constant of the circuit of capacitor 240 and resistor 241 is equal to at least twice the time required for the main controller to cycle from cross-to-main-tocross street green lights 103 on, and therefore the circuit through the capacitor 240 cannot affect the latching relay 67 under the conditions set forth above, and this relay is entirely under control of the timing circuit 53. Thus, it is evident that at any time after termination of illumination of the main street amber lights 104, which causes the relay 256 to be energized, if a further vehicle comes along, the controller of FIGURE 1 cycles in a normal manner through a second cross street green lights 103 on, and then back to the main street green lights 1 on where it holds, if no further vehicles are detected.

If the cross street detector 225 is tripped while the cross street green lights 103 are illuminated, then the interval that these lights are on is extended by operation of relay 228. One side of the winding of relay 228 is returned to ground over leads 226 and 227 and through cross street detector 225, while the other side of the winding is returned to the cross street green high voltage lead through a diode 269, resistor 270 and terminal 126. As previously stated, the winding of the relay is shunted by a capacitor 254. The relay 228 has a movable contact 272 and a fixed contact-273, which are normally disengaged from one another but are brought into engagement upon energization of the relay. The movable contact 271 is connected via a lead 273 to a further fixed contact 268 of latching relay 256, the fixed contact 268 being engaged by movable contact 267 of the relay 256 when the relay is energized, which is the opposite condition to that illustrated in FIGURE 3. The movable contact 267 of the relay 256 yis connected over a 4lead 275 and through a capacitor 276 to a lead 279 which returns the circuit to the junction -point 239. The fixed contact 272 of the relay 228 is returned via a lead 274 and through a resistor 252 to a further fixed contact 246 of the relay 229, which is adapted to be engaged by the movable contact 245 thereof, when the relay is energized.

In operation, the cross light detector 225 is tripped, the latching relay 229 is energized, as is the latching relay 67, initiating a light cycle. Upon illumination of the main street amber lights 104, the latching relay 256 is energized and the movable contacts of relays 256 and 229 are returned to the positions illustrated and maintained there, until the main street amber lights 104 are turned off. Thereafter, if the cross street detector 225 is tripped while the cross street green lamps 103 are illuminated, both of the relays 228 and 229 Will be energized, the contacts of latching relays 229 and 256 thereafter remaining in positions opposite to those illustrated in FIGURE 3, -until the next time the main street amber lights 104 are illuminated.

When the relay 228 is energized, a continuous circuit is completed from the high voltage junction 239 ofthe circuit of FIGURE 3 to the common ground lead 151 of FIGURE 1 via the circuit lead 279, capacitor 276, lead 275 contacts 267 and 266, lead 273, contacts 271 and 272, lead 274, resistor 252, contacts 246 and 245, resistor 250, and lead 251 to terminal 153, all in FIG- URE 3, and terminal 153, resistor 152 and capacitor 54 of FIGURE l. A negative pulse of current is conducted through the circuit, partially charging capacitor 276 and adding to the charge on the capacitor 54 in FIGURE 1. As each vehicle trips the cross street detector 225, an

additional charge is added to both of the capacitors in series, the charge applied to the capacitor 54 prolonging the interval during which the cross street green lights 103 are illuminated. The maximum interval for illumination of the cross street green lights is determined by the rating of the capacitor 276, since after a predetermined number of current pulses resulting from tripping of the cross street detector 225, the capacitor 276 becomes lfully charged and no further current pulses are passed to the capacitor 54. The capacitor 54 now becomes discharged and the apparatus reverts to the main street green lights 1 on. Since the contacts of the relays 256 and 229 are in their closed positions, a permanent bias is not applied to the terminal 153 and the apparatus cycles back to the cross street green lights 103 on, after a predetermined length of time as determined by the timing circuit 53. As the apparatus is cycling back to the cross street green 103 on, that is, initially the main street red lights 96 are turned otI and the amber lights 104 turned on, the latching relay 256 becomes energized and the movable con- 13 tact 267 engages the fixed contact 266, which connects a resistor 269 across capacitor 276 causing it to discharge rapidly. The capacitor 276 is now ready for a further cycle of operation.

It is seen that the traflic actuated controller of FIG- URE 3 may be coupled directly into the basic controller circuitry illustrated in FIGURE l and adds a further trafiic control capability to the basic controller. The combination is made by merely connecting the terminals or the circuitry of FIGURE 3 to specied terminals of the circuitry of FIGURE 1. The apparatus of FIGURE 3 is compatible not only with the apparatus of FIGURE 1 but with that of FIGURE 2 and is particularly valuable where a .factory is letting out, and not only would there be a large number of cars but also a large amount of pedestrian traffic to be controlled at the given intersection.

Flashing light mode Referring now specifically to FIGURE 4 of the accompanying drawings, there is here illustrated a still further auxiliary unit which may be coupled directly into the controller circuitry illustrated in FIGURE 1. The unit of FIGURE 4 is employed to cause the signal lights to blink in accordance with a predetermined pattern, and specifically is employed during ofi hours to cause the main street amber lights 104 and the cross street red lights 2 to iiash on and ofi at regular intervals, this being a commonly employed pattern in most cities at intersections, where the cross street does not carry very much traffic during off hours and particularly the evenings and nights. The only alteration of the circuit of FIGURE l necessary to attach the flasher circuit of FIGURE 4 thereto, is to remove the jumper between the terminals 18 and 19, these latter terminals being connected to corresponding terminals of FIGURE 4. Also, `the high voltage terminal 17 is disconnected from the high voltage supply and is connected to a terminal 17 in FIGURE 4. High voltage in FIGURE 4 is -applied to a terminal 271.

Referring nowl specifically to FIGURE 4,'the circuit may be activated either by an on-oif switch 282 or a remote control relay 283. If a voltage is applied from a remote location to a terminal 284, the relay 283 is energized. Also, if the switch 282 is thrown to the On position, high voltage, appearing on a lead 286, is applied via contacts 287 of the switch 282 to a lead 288, which is connected to one end of the winding of the relay 283 and the relay is energized.

Upon energization of the relay 283, it opens its contaots 291 and causes a movable contact 292 to engage a fixed contact 293, concurrently disengaging movable contact 292 from a further fixed contact 294. The fixed contact 293 -is connected over a lead 295 to the right end, 1

as vie-wed, of the heater element 296 of a thermal relay 297, while the movable contact 292 is connected over a ground return lead 289 to the common terminal 52. A further lead 298 is connected to the lead 295 and has its other end connected to the winding of a latching relay 299.

The circuit of FIGURE 4 is thus primed by the energization ofthe relay 283, or closing of switch 282, and remains in the condition describe-d above until the main street green lights 1 are illuminated, asa result of normal cycling tof the controller of FIGURE 1. Upon illumination of the main street green lights 1, high voltage is applied to the terminal 5 and via leads 301 and 382 the high voltage is applied to the left side orf the heating element 296 of the thermal lrelay 297, thereby initiating a heating cycle of the relay. The thermal relay 297 is provided with a bimetallic or heat iiexible contact 303 which, when suiciently Iheated, engages a fixed contact 384, which is lconnected via a lead 306 to a xed contact 387 lof a second latching relay 308. The contact 307 is normally in engagement with a movable contact 389, which is connected to the lead 301 to the terminal 5.

Thus, when the coil 296 of thermal relay 297, producesr sufficient heating of the heat flexible element 303 to bring it into engagement with the contact 384, high voltage on the lead 301 is applied to the flexible contact 383, and via a lead 311, resistor 312 and diode 313 to one side of the winding of the relay 299. The other side of this winding already has been returned over lead 298 to ground through the contacts 293, 292 of the relay 283. The latching relay299 is energized, causing its contacts and .the contacts of the :relay 308 to close on the respective normally open fixed contacts, `the positions being opposite to those illustrated in the figure. The connection between contacts 307, 309 is broken and the heating of the element 2.96 of the thermal relay 297, is discontinued. Movable contact 314 of relay 308 now engages fixed contact 316, which is connected to the high voltage lead 286. Thus, high voltage is applied to the movablel contact 314, which is connected via a lead 317 to one end of the winding of a relay 318, which has its other end connected directly over the return lead 289 to the common yterminal 52.

It should be noted that movable contact 319 of the latching relay 299 now engages a fixed contact 321, which is connected via a lead 322 to the contacts 291l of the relay 283, the contacts 291 now being open. The movable y contact 319 of the l-atching relay 299 is connected via a lead 323 to one side of the winding of the relay 308, thereby priming this relay for operation upon subsequent deenergization `of the relay 283.

Returning to the relay 318, it is 'provided with four movable contacts 324, 326, 327, and 328. The movable contacts 314 land 318 are both connected together and are connected to the high voltage lead 286. When the relay 318 is deenergized, the high voltage movable contact 314 does not engage its cooperating fixed contact 349, whereas the movable contact 328 engages a stationary contact 329, which is connected via a lead 331 to the AC. input terminal 17, which supplies the highl voltage to the circuit tof FIGURE l. Thus, when the relay 318 is energized and the movable contact 328 moves ofi the fixed contact 329, operating voltage is removed from the circuit of FIGURE l, and the circuit is deenergized and becomes inoperative. When the movable contact 328 is disengaged separated from its cooperating fixed Contact 329, it engages a furtherxed Contact 332, which applies high voltage via a lead 333 to a movable contact 334 of a relay 338. The lead 333 is also connected through a resistor 336 and diode 337 to one end of the winding of the relay 338. The elements within a dashed line box 339 constitute an electronic flasher unit, and among these elements therein there are included the niovable contact 334 of the relay 338 and the resistor 336 and diode 337, and the relay 328 itself. The opera-tion of this apparatus is described in detail in my copending applic-ation and it is sufiici-ent to say for purposes of the present description that upon the application of voltage to the lead 333, the contact 334 of the relay 338 periodically engages a cooperating fixed contact 341, thereby developing an intermittent alternating voltage on a lead 342 connected to the stationary contact-341.

The lead 342 is further connected to fixed contacts 343 and 344 of the relay 318, which are adapted to be engaged by the movable contacts 327 and 326, respectively. Since the relay 318 i-s energized, 4the `m0vable contacts 326 and 327 are in engagement ywith the fixed contacts 334 and 333 respectively so that a voltage for hashing the various trafiic lamps is developed on the movable contacts 327 and 326. The contact 327 is connected via a lead 346 to terminal of FIGURES l and 4 which terminal is connected to the amber lights 104 on the main street. The movable contact 326 is connected via a lead 347 to A C. input terminal 18, whi-ch is connected to the cross 4street red lights 2. Thus, the main street amber lights 184 and the cross street red lights 2 are caused to flash on and ofi at a rate determined by a preestablished cycling rate of the fiasher unit 339.

It will be noted that when the relay 318 is deenergized, a connection is established between the A.C. input terminal 18 and the terminal 19 in the circuit of the cross street red signal lamps 2 through thev movable contact 326 of the relay 318 and a further stationary contact 348, this connection being open, of course, when the relay 318 is energized. The movable -contact 324 is adapted, when the relay 318 is energized, to engage a fixed contact 349, which is connected via a lead 351 to a terminal 352, which also appears in FIGURE l, and is connected via a lead 353 to one end, for the winding of the relay 8 as illustrated in FIGURE 1. The purpose for this connection is to prime the circuit of FIGURE 1 to a main street green lights 1 on condition since it is necessary that, at the end of the flasher operation period, the signal lights first go to cross street red lights 2 on and main street green lights on. The energization of the relay 8, as the result of the application of a volta-ge to the terminal 352, insures such operation. When it is desired to terminate the'asher type of operation, the relay 283 is deenergized, either by throwing the switch 282 to the Off position, or removing the control voltage from the terminal 284. The relay 283 upon `being deenergized, returns its contacts to the position illustrated in FIGURE 4, closing the common return circuit of the relay 388 through the contacts 292 and 294 of relay 283, and closing the high voltage circuit to this relay through its contacts 291. Energization of the relay 308 returns its four movable contacts to the positions illustrated, in FIGURE 4 causing contacts 309 and 311 to open thereby deenergizing the coil of relay 298. Concurrently, the relay 318 is deenergized and its movable contacts 314, 316 through 318 return to the position illustrated removing operating voltage from the flasher unit 339 and applying high voltage again to the A.C. input terminal 17 of the apparatus of FIGURE 1. The circuit between terminals 18 and 19 is now closed and high voltage is removed from the terminal 352, so that the relay 8 may again be placed under control of the main circuit.

Remote radio control As previously indicated, it is an object of the present connected to a lea-d 359, which is the common return lead for the radio receiving and controlling circuit 354. Thus, upon application of voltage to the lead 355, the relay 357 is energized. Energization of the relay 357 causes an associated movable contact 358 to engage a lixed Contact 368, and causes a further movable contact 362 tomove off a fixed contact 361 and engage a further fixed contact 363. The movable contact 358 receives a negative voltage via a lead 364 from the radio receiver v354 and applies this voltage to the fixed contact 360,

which is connected via a lead 365 back into the receiver 354. Within the receiver 354, the lead 365 has applied thereto a negative bias in the east-west channel, which inhibits this channel and prevents it from developing a positive voltage on the lead 356. This insures that once a vehicle has obtained control of the receiver 354 further signals, which may call for a contrary operation, can have no effect upon the apparatus.

The movable contact 362 is connected via a lead 366 to a movable contact 367 of relay 368, having a further movable contact 369. The movable Contact 367 is in engagement with the fixed Contact 371, which is connected via a lead 372 to the common ground terminal 48, lwhich is also illustrated in FIGURE 1. Therefore, under the vconditions in which the contacts 367 and 371 are engaged; that is, when relay 368 is deenergized, the common return terminal 48 is connected to a lead 373 through con- I tacts 362 and 363 of the relay 357. Thus, the lead 373 invention to be able to connect an emergency traic light controller directly to the normal signal controller illustrated in FIGURE 1 by merely interconnecting specific terminals on the two units. controller which is completely adaptable to the controller of FIGURE 1 is illustrated in FIGURE 5 and reference is now made specifically to the apparatus illustrated in this latter Figure. The apparatus comprises a radio receiver and signal processing circuit 354, which is described and illustrated in my copending patent application-Serial No. 120,843 iiled'on May 26, 1961 for Traffic Control Systems as indicated in this copending application, an incoming signal (generated by a transmitter also described in the aforesaid application) is processed by the receiver 354 to develop a positive voltage on a lead 355, if the incoming signal has -a subcarrier of one specific predetermined frequency and to develop a voltage on a lead 356, if the modulating subcarrier signal is of a different predetermined frequency. It is assumed `for purposes of explanation that, if a signal is received indicating the desire to turn the cross street green lights 103 on, a voltage will appear on the lead 355, and, if it is desired to turn the main street green light 1 on, then a voltage appears on the lead 356. The receiver 354 includes two channels in its output section, these being referred to as a north-south channel, corresponding to the main street, from which the lead 355 is energized and an east-west channel, from which the lead 356 is energized.

Assume for purposes of explanation that a signal is received calling for illumination of the cross street green lights 103, and lfurther assume that the controller of FIGURE 1 is in a position to illuminate the main street green lights 1. The lead 355 is connected to one end of the winding of a relay 357, the other end of which is An emergency traffic lightj is returned to common ground only when the relay 368 is deenergized; that is, when the east-west channel of receiver 354 has not received a signal. The lead 373 is connected to one end of the winding of a relay 374, one end of the winding 376 through a diode 377 and through contacts 378 and 379 of a relay 381 and further through a diode 382, to the other end of the winding of a relay 383. Thus, a common ground return is connected to each of the aforesaid windings 374, 376 and 383, priming these windings for operation upon the appli` cation of high voltage thereto. The lower end of the winding 374 is permanently connected via a lead 384 and diode and resistor combination 386 to a high voltage lead 387, which is connected to the high voltage A.C. input terminal 17, which also appears in FIGURE l. Thus, immediately upon the closing of the contacts 362 and 363 and the connection of the lead 373 to common ground terminal 48, the relay 374 is energized.

Energization of the rel-ay 374 causes an associated movable contact 388 to engagea Ifixed contact 389, which is connected via a lead 391 `and resistor-diode combination 392 to the terminal 149 of FIGURE 1. The movable contact 388 is connected via a lead 393 to the high voltage lead 387 and therefore upon closure of the contacts 388 and 389, high voltage is applied to the `terminal 149 and energizes the latohing relay 67 of FIGURE 1. In consequence, the necessary apparatus is set into action to switch from the main street green lights 103 on, to the cross street green lights 103 on, the-condition desired by the approaching emergency vehicle. It will be noted that Ithe relay 374 -has a further set of contacts 394 and 396 which are open when its winding is energized. The contact 396 `is connected via a lead 397 and a set of contacts 398 of a relay 399 to the lead 38-7 and thus, when the contacts 398 are closed as they are under the condition being described, high voltage is applied to the lead 397. Ordinarily with the con-t-acts 394 and 396 closed,

v high voltage is applied to the movable contact 394 and When g However, when the relay 374 is energized and the contacts 394 and 396 are open, high voltage is removed Ifrom the timing circuit 53, thereby rendering it inoperative. During this inoperative interval, -it must be realized, the capacitor '4 becomes completely discharged so that as soon as high voltage is again applied to the terminal 85, the timing circuit V56 lires and immediately shifts the red light-green light to green light-red light condition, so as to permit immediate ilow of trafl'lc on the street which has been blocked -by -the passage of the emergency vehicle.

Continuing with the description, the energization of the latching relay 67, as a result of the application of high voltage to the terminal 149 as indicated above, causes the apparatus to switch from a main street green lights 1 on to a cross street green lights 103 on. As soon as the cross street green lights 103 are illuminated, a high voltage -appears on the terminal 126 of FIGURE 1 and the terminal 126 of FIGURE 5, which are one and the same. The high voltage on the lead 126 is applied through a resistor-diode combination 402 to a lead 403 which is connected to the upper end of the winding of the relay `376. The winding of the relay 376 forms the active ele-ment of a flasher unit 404, which isienclosed within .the dashed line box, and is the same as the flasher unit 339 illustrated in FIGURE 4. The operation of these units is described inthe aforesaid pending application.

The flasher unit 404, when energized produces a timed pulsating voltage on a lead `406 in order to selectively energize one of two dual flasher lights 407 or 408. Specifically, when an emergency Vehicle approaches a corner, it is desired to provide a visual display indicating the fact that Ithe vehicle has obtained control. The reason for this is that tw-o emergency vehicles may be approaching an intersection Ion the intersecting streets and may collide if Ieach does not know that the other is present. If blinking signal lights are provided for each direction of approach -to an intersection and the blinking lights are displayed only along the route of the vehicle obtaining control, then the absence of suchV a blinking light would indicate to the driver of a vehicle that a vehicle proceeding on the lother street has obtained control and that the lfirst-named vehicle should stop. The lights 407 are employed to provide a blinking white light along the cross street direction, whereas the lights 408 are employed to provide a blinking White light along the main street. Since, in the example Iunder consideration, the `green lights 1 are to be displayed along the north-south street, the light 407 should be energized with a pulsating voltage, this being more particularly the voltage appearing on the lead 406.

The application of the blinking voltage on the lead 406 to the lights 407 is under control of the relay 383. As previously indicated, one end of the winding of this relay is returned to the common ground terminal 48 over a circuit including, among other elements, the contacts 378 and 379 of the relay 381. The high voltage tor operating the relay 383 is derived from a lead 409, which is connected through a resistor-diode arrangement 411 and a lead 412 to the terminal 126. Th-us, when the 'cross-street green lights 103 are illuminated, high Voltage is applied `to ,the winding of the relay 383 and, if contacts 378 and 379 are closed, t-he relay 383 is energized, causing it to connect 'a movable contact 413 to a xed contact 414. The contact 414 is connected via a lead 416 to the north-south tlasher lights 407. These lights 407 are connected further via a lead 417 to the common terminal 48. The movable contact 413 is connected via a lead 418 and through a set of contacts 419 and 421 of the relay 381 .to a lead 406. In consequence, a pulsating voltage is vapplied to the flasher light 407 causing them to display the appropriate signal to indicate that a vehicle proceeding along the cross street has obtained control of the traic signal lights at the intersection. It is wished to emphasize 4that this blinking signal is established only 18 after the cross green lights 1 have become illuminated, this being sensed in the circuit of FIGURE 5 as a result of the connection of the energizing circuits of the relays 374 and 376 to the terminal 126 in the lhigh voltage lead to the east-west .green lamps 103 of FIGURE 1.

It should be noted that the relay 383 includes a Ifurther set of contacts 422 and 423 which are -connected in the ground return circuit of the coil winding of the relay 381. This relay 381 corresponds to the relay 383 in that, when energized, Vit causes the pulsating high voltage on the lead 406 .to be applied to the main street flasher lights 408. Upon energization of the relay 383, the contacts 422 and 423 are opened .thereby insuring that the relay 381 cannot be energized and therefore mitigating any possibility that the flasher lights 407 and 408 may be concurrently energized. The contacts 378 and 379, which are part of the relay 381, are connected, as previously indicated, in the energizing circuit of the relay 383. Therefore, if the relay 381 is energized, the relay 383 cannot be energized, insuring that the flasher lights 407 cannot be illuminated when the llasher lights 408 are so illuminated.

The apparatus of FIGURE 5 is maintained in the condition, as set forth in the immediately preceding description, until termination of receipt of the control signal by the radio receiver 354. Upon termination of the receipt of signal by the receiver, voltage is removed from the lead 355, the relay 357 becomes de-energized and breaks approaching vehicle called for the cross street green lights 103 to be on and the green lights should already be on for movement in this direction, then the apparatus of FIGURES 1 and 5 would operate as described, except that voltage would already appear on terminal 126 at the time of receipt of the radio signal, and therefore the operation of the relays 374, 376 and 383 would be immediate. Thus, the application of voltage to the terminal 149 would have no efect upon the circuit of FIGURE 1, the cross street green lights 103 on condition wouldbe maintained, the blinker lights 407 would be immediately illuminated, and high voltage would be removed from the terminal 85, so that the timer circuit 53 would be deactivated until after the emergency condition would be over.

If a signal would be received by the radio receiver 354 which called for the main street green lights 1 to be on,

then a high voltage would appear on the lead 356 and effect energization of the relay 368. The relay 368 would cause its movable Contact 367 to engage a movable contact 426 connected to a lead 427. The movable contact 367 is conected through contacts 361 and 362 of the deenergizcd relay 357 to the common ground terminal 48, and therefore the lead 427 is grounded, or returned to the electrical common of the system. The lead 427 is connected in the ground return of the relays 381 and 399, and is an alternative ground return circuit through a diode 428 for the relay 376 in the flasher unit'404. The relay 381 serves the same purpose as the relay 383, as previously described. The relay 399 has the same function for the traffic lights on the main street as the relay 374 for the traic lights on the cross street and, 0f course, the relay 376 serves the same function for the trac lights on both streets.

. The relay 399 is connected through the diode-resistor combination 386 to the high voltage lead 387 and therefore this relay is immediately energized. It closes a set .19 of contacts 431, the movable contact being connected to the lead 387 to apply a high voltage to the terminal 151 and thereby energize the latching relay 44 of FIGURE 1. This causes the apparatus of FIGURE 1 to cycle from the cross street green light 103 on to the main street green lights 1 on, if the cross street green lights were originally illuminated, and to remain in with the main street green lights 1 on position if the main street green lights were already illuminated. Upon the application of high voltage to the main street green lights 1, this high voltage appears on the terminal 5, and is applied to the high voltage lead 403 and energizes the fiasher unit 404. The high voltage onthe terminal is also applied via a lead 432 to the winding of the relay 381 energizing the relay. Relay 381, closes its movable contact 419 on the fixed contact 433, so that voltage on lead 406 is applied through contacts 413 of relay 383 and contacts 419 and 433, and over the lead 434 to the flasher light 408.

It Will be noted that in the apparatus of FIGURE 5, control of the timing circuit 53 is achieved by removing the jumper 76 from the circuit of FIGURE 1 and connecting the terminal 85 to the circuitry of FIGURES. On the other hand, in the apparatus of FIGURES 2 and 3 relating specifically to the Walk-Dont Walk unit and the trafiic actuated unit, respectively, control of the timing circuit is achieved by applying a negative holdofi voltage to the terminal 153. The reason for the two types of control is that in the latter two apparatus; that is, the apparatus of FIGURES 2 and 3, it is desired to have a delay in return to normal operation, after operation of the associated apparatus. When employing the apparatus of FIGURE 5, it is desired to have an immediate return to normal condition, after termination of the emergency condition. Thus, the necessity for provision of two different types of controls for hold-ofi operation of the timing circuit 53.

The various apparatus described in FIGURES 2 through 5, inclusive, are compatible with one another. For instance, the application of voltage to the terminal 149 from the lead 236 in FIGURE 3 may be prevented if an emergency vehicle wishes totake control of the system, by merely inserting a set of contacts in the leadv 242 which would be controlled by the relay 399 of FIG- URE 5 upon energization of that relay. Further, any auxiliary equipment may be disabled by the emergency controller of FIGURE 5 by the simple expedient of removing the high voltage from any of the other circuits; this being accomplished by an appropriate set of contacts in the apparatus of FIGURE 5 for operation by one or the other of the relays 383 or 399, or to control where necessary the application of high voltage to specific elements of the other circuits, or both. The techniques involved in such adaptations are obvious to the person who is skilled in the art and form no particular part of the present invention. The present invention is specifically directed to the features of connecting each of the auxiliary units for operation with the traffic light controller, and to a basic traffic light controller which may be employed with a large number of various types of auxiliary units.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of the circuits which are specifically illustrated and described, may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What I claim is:

1. In an apparatus for controlling the movement of each movable contact, a timing means including an electron tube and a capacitor iconnected from grid toicathode of the latter, an operating circuit for the first operating relay closed by both movable 'and meeting fixed contacts of the second operating relay and one movable and meeting xed contactl of the first latching relay including the timing means, a first circuit means closed by one movable contact and its meeting fixed contact of the first operating relay for energizing the set of traffic lights on one street, an operating circuit for the second operating relay through the other movable contact and one meeting! fixed contact of the f irst operating relay and the other movable contact and meeting fixed contact of the first latching relay, a second circuit means closed by both movable contacts and their meeting fixed contacts of the second operating relay for energizing the set of traffic lights on the other street, a second latching relay having dual movable contacts and a fixed contact meeting with each movable contact, a vehicle operated switch, an operating circuit for the second latching relay closed by the vehicle operated switch, an operating circuit for the first latching relay through one movable and one meeting fixed contact of the second latching relay and third circuit means connected to the set of trafiic lights on the first street including a resi-Stor and a diode rectifier in series through the other movable contact and meeting fixed contact-.of the second latching relay to the timing device for applying a counter voltage to the latter.

2. In an apparatus for controlling the movement of traffic through the intersection of two streets, first and second sets of traffic lights on one street, a set of traffic lights on the other street, a first operating relay having -dual movable contacts, a fixed contact meeting with one movable contact and a pair of fixed contacts meeting with the other movable contact, a second 'operating relay having dual movable contacts and a fixed contact meeting with each movable contact, la third relay having a movable contact and a pair of fixed contacts meeting with the movable contact, a first latching relay having dual movable contacts and la fixed contact meeting with each movable contact, an operating circuit for the first operating relay through both movable contacts and the meeting fixed contacts of the second relay and one movable contact and meeting fixed contact of the first latching relay, an operating circuit for the second operating relay through the one movable contact and oneA meeting fixed contact of lthe first relay, the movable contact and one meeting fixed contact of the third relay, and the other movable contact and meeting fixed contact of the first relay, and the other movable contact and meeting fixed contact of the first latching relay, an operating circuit for the third relay through the other movable contact and the meeting fixed contact of the first operating relay, a first circuit means closed by the latter movable contact and meeting fixed contact of the rst operating relay for energizing one set of traffic lights on the first street, a second circuit mean-s closed by the latter movable contact and other meeting fixed contact of the first operating relay and the movable contact 'and other meeting fixed contact of the third relay for energizing a second set of traffic lights on the first street, and a third circuit means closed by both movable contacts and meeting fixed contacts ofthe second operating relay for energizing the set of traffic lights on the other street, a pair of latching relays having mechanically interconnected movable contacts and meeting fixed contacts, a vehicle operated switch, an operating circuit for the first of the latter latching relays closed by the vehicle operated switch, an operating circuit for the first latching relay closed by the latter of the pair of latching relays, and a shunt circuit across the second set of traffic lights on the first street including a diode rectifier and a resistor connected in series with said set of' traffic lights through the movable contact and meeting fixed contact of the second of the pair of latching relays and back to said set of trafiic lights.

3. In an apparatus for controlling the movement of traffic through the intersection of two streets, first, second and third sets of traffic lights on one of the streets and a set of traffic lights on the other street, a first operating relay having dual movable contacts and a pair of fixed contacts meeting with each movable contact, a second operating relay having dual movable contacts, a fixed contact meeting with one of the movable contacts and a pair of fixed contacts meeting with the other movable contact, a second operating relay having dual movable contacts, a fixed Contact meeting with one of the movable contacts and a pair of fixed contacts meeting with the other movable contact, a third relay having a movable contact and a pair of xed contacts meeting with the movable contact, a first latching relay havingk dual movable contacts and a fixed contact meeting with each movable contact, a timing means including an electron tube and a capacitor connected from grid to cathode of the latter, an operating circuit for the first -operating relay through both the movable and their meeting fixed contacts of the second operating relay and one movable and its meeting fixed contact of the first latching relay including the timing means, a first circuit means closed by the other movable contact and one meeting fixed contact of the first operating relay for energizing the first set of traffic lights on one street, ,an operating circuit for the second operating relay through one movable contact and meeting fixed contact 4of the first operating relay, the movable contact and one meeting fixed contact of the third relay, and the other movable and other meeting fixed contact of' the first operating relay, an operating circuit for the third relay through the other movable contact and the meeting fixed contact of the first operating relay, a second circuit means closed by the other movable and other meeting fixed contact of the first operating relay and the movable contact and other meeting fixed contact of the third relay for energizing a second set of traffic lights on the one street, and a third third circuit means closed by the one movable contact and other meeting fixed contact of the first operating relay for energizing the third set of traffic lights on the one street, and a fourth circuit means closed by the other movable and other meeting fixed contact of the second operating relay -for energizing the set of traffic lights on the other street, a pair of latching relays having mechanically interconnected movable contacts and meeting fixed contacts, a vehicle operated switch, an operating circuit for the first of thev latter latching relays including the vehicle operated switch, an operating circuit for the first latching relay closed by the movable and meeting fixed contact of the first of the latter latching relays including a resistor and a capacitor in parallel, and a shunt circuit across the second set of traffic lights on the first street including a diode rectifier and a resistor connected in series to said last mentioned set of traffic lights closed by the movable contact and its meeting fixed contact and the winding of the second of the pair of latching relays back to said last-mentioned set of traffic lights.

4. In an apparatus for controlling the movement of traffic through the intersection of two streets, first, second and third sets of traffic lights on one of the streets and a set of traffic lights on the other street, a first operating relay having dual movable contacts and a pair of fixed contacts meeting with each movable contact, a second operating relay having dual movable contacts, a fixed contact meeting with one of the movable contacts and a pair of fixed contacts meeting with the other movable contact, a second operating relay having dual movable contacts, a fixed contact meeting with one of the movable contacts and a pair of fixed contacts meeting with the other movable contact, a third relay having a movable contact and a pair of fixed contacts meeting with the movable contact, a first latching relay having dual movable contacts and a fixed contact meeting with each movable contact, a timing means including an electron tube and a capacitor connected from grid to cathode of the latter, an operating circuit for the first operating relay through both movable and meeting fixed contacts of the second operating relay and one movable and meeting fixed contact of the first latching relay and the timing means, a first circuit means closed by the other movable contact and one meeting fixed contact of the first operating relay for energizing the first set of traffic lights on one street, an operating circuit for the second operating relay through one movable contact and meeting fixed contact of the first operating relay, the movable contact and one meeting fixed contact of the third relay, and the other movable and other meeting fixed Contact of the first operating relay, an operating circuit vfor the third relay through the other movable contact and the meeting fixed contact of the first operating relay, a second circuit means closed by the other movable and other meeting fixed contact of the first operating relay and the movable Contact and meeting fixed contact of the third relay for energizing a second set of traffic lights on the one street, and a third circuit means closed by the one movable contact and other meeting fixed contact of the first operating relay for energizing the third'set of traffic lights on the one street, and a fourth circuit means closed by the other movable and'other meeting fixed contact of the second operating relay for energizing the set of traffic lights on the other street, a pair of latching relays having mechanically interconnected movable contacts and meeting fixed contacts, a vehicle operated switch, an operating circuit for the first of the latter latching relays including the vehicle operated switch, an operating circuit -for the first latching relay through the movable and meeting fixed contact of the first of the latter latchingtrelays, including a resistor and a capacitor in parallel, a holding relay having a movable ycontact and a meeting fixed Contact, an operating circuit for the holding relay including the vehicle operated switch, and through the winding of the holding relay and a diode rectifier and aresistor connected in series to the first set of traffic lights on the first street, and a holding circuit for the first latching relay from the timing device closed by vthe other movable and meeting fixed contact of the first of the pair of latching relays, the movable contact and meeting fixed Contact of the holding relay, the movable contact and meeting fixed contact of the second of the pair of latching relays, and extending through a second capacitor and the first capacitor and resistor in parallel and the winding of the first latching relay.

References Cited by the Examiner UNITED STATES PATENTS 2,144,536 l/l939 Horni 340-44 2,817,724 12/1957 Skidgel 340-41 2,931,923 4/1960 Cegan 340--41 3,056,946 10/ 1962 Brockett 340-44 3,090,032 5/1963 Shand 340-41 i NEIL c. READ, Primary Examiner.

THOMAS B. HABECKER, Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2144536 *Jul 8, 1936Jan 17, 1939Horni Paul PTraffic signal
US2817724 *Nov 7, 1955Dec 24, 1957Skidgel William ACircuit controller in traffic control system
US2931923 *Nov 3, 1958Apr 5, 1960Eastern Ind IncElectrical control circuit
US3056946 *Feb 12, 1958Oct 2, 1962Lab For Electronics IncTraffic actuated control system and apparatus
US3090032 *Aug 27, 1957May 14, 1963Ass Elect Ind Manchester LtdAutomatic traffic signalling systems
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4704610 *Dec 16, 1985Nov 3, 1987Smith Michel REmergency vehicle warning and traffic control system
Classifications
U.S. Classification340/916, 340/922, 340/906, 361/166
International ClassificationG08G1/08, G08G1/07
Cooperative ClassificationG08G1/08
European ClassificationG08G1/08