US3484742A - Traffic signaling system - Google Patents

Description

- name, 196 M.=JEFFER Y 31 ,434,742:

'flywnc SIGNALING SYSTEM Filed Iay'lQ, 1966 4 Sheet-548M611 2 4 s s; a s

INVENTOR. Q WALTER 1A.. JEFFERS.

ATTORNEY.

Dec, 16, 969 I 'w. M. JEFFERS I I TRAFFIC. SIGNALING SYSTEM v 4 Sheets-Sheet s 'Filed Hay 19L 1966 mam INVENTOR. WALTER H. JEFFERS.

ATTORNEY.

16,1969 WMJEFFERS 3,484,742

TRAFFIC simmmuc SYSTEM F iled'hlay 19 196.6- 4 Sheets-Sheet; 4

INVENTOR- WALTER u. JEFFERS.

ATTORNEY.

United States Patent York Filed May 19, 1966, Ser. No. 551,428 Int. Cl. G08g /00; H04q 1/00 US. Cl. 340-40 4 Claims ABSTRACT OF THE DISCLOSURE Disclosed is a traffic signal system for a multiplicity of intersections wherein a variable cycle time master timer produces 100 stepping pulses, a zero pulse, and positive and negative polarity potentials mainfesting the half cycle sector of the timer on each of three wires connected to each intersection controller. A single decimal counter with a capacity of 100 counts has a plugboard associated therewith for predetermined splits, and settable switches for determining offset. The counter is normally stepped by the stepping pulses, and upon coincidence with each split count activates the next traffic movement. The offset switches in cooperation with the counter produce two controls, one at the preset offset count and the other at the offset count +50 (180 later) which, together with the zero pulse and the positive and negative potentials from the master timer, set storage devices to maintain the counter, advance the counter or retard it, by respectively allowing free passages of the stepping pulses, gating additional pulses thereto from a local pulser, or withholding the stepping pulses so as to bring the counter gradually into phase synchronism with the master.

This invention has to do with highway traffic signaling, and in particular with an interconnect system for controlling a multiplicity of secondary traffic signal control lers in the system.

The invention has as an object an interconnect system involving a unique arrangement for actuating the secondary controllers of the system from one movement to the next, for providing a selected one of several different ofisets between a secondary controller and the master timer, for checking the offset relationship between the secondary controller and the master timer a number of times during each cycle of the master timer, and for advancing, or retarding, a secondary controller by relatively small increments during a cycle of the master timer depending on whether the secondary controller is running ahead, or behind, the master.

This invention may be used as an interconnect system for the secondary controllers, as disclosed in my Patent No. 3,208,038, issued Sept. 21, 1965. The interconnect system for this invention takes the place of the three dial motors 261, 262, 263 in said patent.

In general, the interconnect system includes a variable speed cyclically opera ed master time which functions to produce a multiplicity of equally and closely spaced pulses during each cycle of its operation. A pulse counter is associated with each secondary controller for counting the pulses transmitted from the master timer. The system also includes means for selecting certain ones of the counted pulses and transmitting the selected counted pulses to the secondary controller and, upon the transmission of a selected common pulse, the secondary controller will be advanced from one major movement to the next. Accordingly, a secondary controller is operated by the selected counted pulses to provide a desired split for each cycle or total period of the master timer and accordingly, such pulses may be referred to as split pulses.

The master timer also functions to energize other cir- 3,484,742 Patented Dec. 16, 1969 cuits during different parts of the cycle. These other circuits serve to check the relationship, or offset, between the master timer and a secondary controller and, in the event the secondary controller is not in synchronism with the master timer at the desired offset, means is provided for adding to, or subtracting from, the split pulses fed to the counter, whereby the counter will count faster, or slower, than normal to cause the controller to advance, or retard, relative to the master timer until the two are in synchronism at the desired oflset.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

In the drawings:

FIGURE 1 is a block diagram of my system.

FIGURE 2 is a side elevational view of a master timer arrangement which may be used in my system.

FIGURE 3 is a view illustrating the relative position in which the pulsing disks of the master timer are mounted on the disk shaft.

FIGURE 4 is a diagram of the switching arrangement for selecting different offset and split functions.

FIGURE 5 is a schematic wiring diagram of the pulse counting and offset selector arrangement.

FIGURE 6 is a schematic diagram of the circuity involved in the split selector.

FIGURE 7 is a schematic wiring diagram of the offset selector circuity.

FIGURE 8 is a fragmentary sectional view of a plug board taken on a line corresponding to line 88. FIG- URE 6.

FIGURE 9 is a schematic wiring diagram of the amplifier arrangement between the counter and the secondary controller.

A form of master pulsing timer is schematically shown in FIGURES 2 and 3. In this arrangement, disks 20, 21, 22, 23, are fixedly mounted on a shaft 24 journalled in bearing supports 25, 26. The shaft 24 is rotated in counterclockwise direction, FIGURE 3, by a motor 28 which is of the variable speed type.

The disk 20 is formed with a multiplicity of slots 27. In a practical embodiment of this invention, the disk 20 was provided with of the slots 27, which were equally spaced circumferentially around the disk. A light source 30' is mounted at one side of the disk 20 and arranged to project a beam through the slots 27 to a photo cell 31.

A disk 21 is formed with a slot 33, which extends circumferentialy of the disk slightly less than The disk 22 is formed with similar slot 35, the slot 35 being offset 180 from the slot 33. The disk 23 is formed with a slot 36 which, in circumferential dimension, is only a fraction of the slots 33, 35.

A light source 37 and a photo cell 38 is provided for the disk 21. A light source 40 and a photo cell 41 is provided for the disk 22, and a light source 43 and a photo cell 44 is provided for the disk 23. The light sources 30, 37, 40 and 43, are energized continuously from the hot feed 45.

As each slot 27 is moved into registration between the light source 30 and the photo cell 31, a pulse is transmitted through conductor 47, amplifier 48, to wire 49. During the time the slot 33 in disk 21 is moving intermediate the light source 37 and the photo cell 38, current is supplied to the conductor 50, to amplifier 51, to wires 52, 53. During the time the slot 35 is positioned intermediate the light source 40 and photo cell 41, power is supplied to the conductor 54, amplifier 55, wire 56, to wire 53. Actuation of photo cell 44 by light from lamp 43 passing through slot 36 of disk 23, provides power to conductor 57, amplifier 58, wire 59. The output of amplifiers 48, 51 and 58 is positive. The output from amplifier 55 is negative.

The pulses impressed on conductor 49 are transmitted through an offset control unit, shown in FIGURE 7, to a pulse counting means, shown in the upper portion of FIGURE 5. The pulse counter functions to count the pulses impressed on it and, as will appear later, means is provided for selecting certain of the counted pulses for actuating the local trafiic signal controller.

In the embodiment disclosed in FIGURE 5, the counter consists of two Dekatron multi-cathode glow tubes, which are particularly convenient because they give a visual indication of the count, as well as an electrical output for each count. Bulletin D-4009, published by Baird-Atomic Inc., 1961, may be referred to for the specific structural arrangement of these tubes.

The counter tubes are indicated at 60, 61, and are so connected in the circuit as to provide two decades for counting the pulses continuously. The disk 20 is formed with 100 slots 27. Each pulse impressed on conductor 47 moves the unit decade, tube 61, forward one step. On the tenth count, the unit decade 61 sends a pulse to the tens decade 60, advancing it one step. The ten cathodes of each counter tube are numbered to 9. In the arrangement shown in FIGURES and 6, plug boards are employed as a convenient means for selecting split pulses to be transmitted to the secondary controller. The cathodes of the tens counter tube 60 are connected to a plug board 63, FIGURE 6, and the cathodes of the units counter tube 61 are connected to a plug board 64. These plug boards 63, 64, are provided with vertically extending conducting strips VSO to V59. There are horizontal conducting strips HS1HS10 located rearwardly of the vertical strips, see FIGURE 8. The boards and the strips VS and HS are formed with aligned apertures 67 for the reception of a conducting plug 68. In this manner, any vertical strip may be electrically connected to any horizontal strip.

The cathodes 09 of the tens tube 60 are connected to the vertical strips VSO-VS9 of the board 63, and the cathodes of the unit counter tube 61 are similarly connected to the vertical strips of the board 64. A wire 70 extends from the zero cathode of the tube 60 to wire 71, which is connected to the vertical strip VSO on board 63. The bottom of this strip is connected by wire 73 to diode 74.

A wire 77 extends from the zero cathode of tube 61 to the vertical strip VSO of board 64, and the bottom of that strip is connected to diode 78. Attention is called to the fact that each of the cathodes of the tubes 60, 61, are connected by resistors 79, to the ground wire 80.

The diodes 74, 78, are connected back to back to form a conventional AND circuit, the junction 81 of which is connected by wire 82 to an amplifier 83, the output 84 of which extends to the secondary controller and, when provided with power, is effective to move the secondary controller out of its first movement. All the horizontal strips HS1HS10 of the plug boards are also connected to diodes arranged in back to back form to provide AND circuits. The amplifier arrangement is shown in FIGURE 9. The wire 82 extends to the grid of the tube V of the amplifier. A positive supply of twenty volts is fed to the grid through the resistors 85, 86. The counter tube cathode resistors are in the order of one hundred K, and the resistor 85 is tWo megohms. Accordingly, the potential on the grid of V10 will be maintained below that which will fire the tube. However, when the diodes 74, 78, are blocked by a selected count, as by the count zero-zero, FIGURE 9, by the thirty volt plus output of the counter tubes, the potential on the grid of V10 will raise sufficiently to fire the tube. With V10 conducting, relay 87 is pulled in, closing the contacts 88, 89, to transmit power from the source 97, through Wire 84, to the secondary controller.

The remaining cathodes 1-9 of the tens tube 60 are connected to the remaining vertical strips VSl-VS9 of the board 63 by wires 101-109. The remaining cathodes 19 of the units tube 61 are connected to the remaining vertical strips VS1-VS9 of the unit board 64 by wires 111119.

Referring to FIGURE 6, the horizontal strips HS1- HS10 of each of the boards 63, 64, are connected together through a pair of diodes to provide an AND circuit, as in the case of the diode circuit 74, 78. For example, the top horizontal strips HSl of the boards are connected to the diodes 121.

Referring to FIGURE 6, a plug 68 is inserted in the tens board 63 to connect the vertical strip V53 with the horizontal strip HSI. A plug 68 is inserted at the junction of strip VSl, and the horizontal strip H81, in the board 64. As the disk 20 rotates from zero position to slot number 30, the ten tube 60 has been advanced so that the cathode number 3 thereof provides power to the horizontal strip HS1 of the tens board to the diode 120. When the disk rotates to bring the next slot into registration with the photo cell 31, a pulse is emitted from the No. 1 cathode of the unit tube 61. With the plug 68 positioned, as stated, in the board 64, this pulse is transmitted to the diode 121. The junction 122 between the diodes 120, 121, is connected by wire 123, through closed contacts 124, 125, of relay 126. Contact 125 is connected by wire 127 to contact 128 of relay 209. This contact is engaged by contact 220 to provide power through wire 132 to amplifier 133, the output 134 of which extends to the secondary controller to move it out of its second movement. It will be recalled that with the disk 20 in zero position, power was supplied to the secondary controller through conductor 84 to terminate the first movement of the controller.

Referring further to FIGURE 6, there is a plug 68 inserted at the junction of the horizontal strip HS2 and the vertical strip VS6 in the tens board 63. A plug is also inserted in board 64 at the junction of the horizontal strip HS2 and the vertical strip VS2. It will be apparent that when the disk 20 has rotated further to produce sixty pulses to the counters, cathode number 6 of the tens tube will be energized and two slots later cathode number 2 of the units tube will be energized, whereby diodes 137, 138 will be blocked. The junction 140 between these diodes is connected by wire 141, through closed contacts 142, 143, of relay 126, through wire 144, closed contacts 228 of relay 209, to wire 147, amplifier 148, the output of which extends to the secondary controller to terminate the third movement thereof.

In the arrangement shown, the secondary controller is set up for a cycle of three movements and from the description so far, it will be apparent that upon a complete rotation of the disk 20, the secondary controller is actuated successively through the three movements. The amplifiers 133, 148 are similar to the amplifier 83.

With the plug arrangement above described, the first movement of the secondary controller is terminated at the zero count, the second movement at the count of 31, and the third movement at the count of 62.

It will be now apparent that the secondary controller cycle may be given many different split arrangements, depending on the insertion of the plugs 68 into the apertures 67 of the plug boards 63, 64.

The relays 126, 209, shown at the right center of FIG- URE 6, and the three relays shown below, are split selector relays. These relays may be operated from the location of the master timer, or other remote point, to efiect the selection of other splits. Basically, this is accomplished by inserting additional sets of the plugs 68 in the plug boards, and the relays function to shift the board outputs from one set of plugs to another. For example, it will be apparent, from the above description, that with relays 126, 209, de-energized, the four plugs positioned, as described above, provide for the split 0-31-62.

To illustrate a different split arrangement, a feed is placed upon wire 155, FIGURE 6. This may be done by moving contact 156 into engagement with contact 157,

FIGURE 4. The switch contacts 156, 157 may be located at the master timer. This feed closes relay 158, through diode 159. The opposite side of the relay coil is connected to a common return 160. Energization of relay 158 produces no effect until relay 161 is energized through wire 163. Wire 163 is energized simultaneously with one of the signal circuits from the secondary controller. Normally, this would be upon display of the amber signal following the termination of the green signals first movement. The relatively brief closure of relay 161, in combination with the already closed relay 158, transmits a hot feed from wire 165, through contacts 166, 167, of relay 158, wire 168, contacts 169, 170, of relay 161, to wire 171, relay coil 126, the opposite side of which is connected through wire 173, to the ground wire 174, the connection to ground being through resistor 175. Relay 126 is locked in from the supply 165, by way of contacts 178, 179. Contact 143 is now moved into engagement with contact 180, which is connected by wire 181 to the junction 182 between the diodes 183, 184, connected to the horizontal strips HS4 of the boards 63, 64. Contact 125 is moved into engagement with contact 187, which is connected by wire 188, to the junction 190 between the diodes 191, 192, connected to the horizontal strips H83 of both boards.

There is a plug 68A inserted in the junction of the horizontal strip H83 and the vertical strip VS3 in board 63. Another plug 68A is inserted in the junction of horizontal strip H53 and vertical strip VS8 in the board 64. There is also a plug 68A inserted in the junction of strips H84 and VS6 in board 63, and a plug 68A is inserted in the junction of strips H54 and VS7 in board 64. Accord ingly, energization of the relays 158, 161 results results in transferring the second and third movement of the tratfic signal controller to a different count-namely, 38 and 67. To return the operation of split L, the relay 158 is de-energized. When the relay 161 is again energized with the amber signal, the relay 126 is shorted out because contact 167 of de-energized relay 158 is now connected to the ground wire 174. Accordingly, relay 126 will release.

A third split may be obtained by moving the contact 156 into engagement with contact 200, FIGURE 4, to impress a negative supply on wire 155. This supply will pull in relay 201, through diode 202. After relay 161 is again energized with the amber signal, the second and third movements of the secondary controller are terminated by plugs 68B inserted at the juncture of the strips HS5 and VS4, and at HS6 and VS7 in board 63. Matching plugs 68B are inserted at the juncture of strips HS5 and VSO, and at the juncture of HS6 and VS2 in board 64.

When relays 201 and 161 are thus energized, contact 203 of relay 201 is moved into engagement with contact 204, providing a hot feed from line 165, to wire 206, through contacts 205, 207, of relay 161, wire 208, to relay 209. Relay 209 is held in by power from line 165, wires 210, 211, closed contacts 212, 213, and Wire 214. The horizontal strips HS5 of the plugs boards are connected to the diodes 215, 216. The junction 217 is connectedby wire 218, to contact 219, contact 220, wire 132, to, amplifier 133, the output 134 of which terminates the second movement of the secondary controller. The horizontal strips HS6 are connected to the diodes 223, 224. The junction 225 is connected by wire 226, through contacts 227, 228, to wire 147, amplifier 148, to the output 150, which terminates the third movement of the secondary controller.

It will be obvious that more of the plugs 68 may be inserted in the plug boards 63, 64, and additional relays may be added to obtain additional splits. In other words, the number of splits is limited only by the number of horizontal strips HS on the boards, and the number of switching relays.

The system also includes means for obtaining different offset relations between the secondary controller and the master timer, and also for checking the offset twice during each cycle of the master timer.

Referring to FIGURE 5, there are three offset switches 230, 231, 232. These switches are of the rotary type having movable contacts 233, 234 and 235, respectively. Each switch has ten fixed contacts. The fixed contacts of switch 230 are connected to the cathodes of the counter tube 60. The switches 230, 231, are cross-wired in order to give another county fifty percent later in the cycle. As shown in FIGURE 5, the contact 233 of switch 230 is engaged with the number 3 fixed contact, which is connected to the number 3 cathode of the counter tube 60 by the wire 103. Also, by wire 237, the number 8 contact on switch 234 is connected to the number 3 cathode of tube 60.

The fixed contacts of switch 232 are connected respectively to the cathodes of tube 61. In FIGURE 5, the movable contact 235 is shown engaging the number 5 contact which is connected by the wires 240, 115, to the number 5 cathode of tube 61. Wire 241 extends from the contact 233 of switch 230 to supply power through closed contacts 242, 243, of relay 245, through wire 247, through contacts 248, 249' of relay 250, wire 251, to the cathode of diode 252, the anode of which is connected to line CA which extends to the circuitry shown in FIGURE 7. A wire 255 extends from the movable contact 234 of switch 231. With contact 234 engaging contact 3 of switch 231, a pulse is impressed on wire 255 from the number 8 cathode tube 60, due to the fact that the number 3 contact of the switch is connected to wire 108, by wire 257. Wire 255 extends through contacts 258, 259, of relay 245, Wire 260, contacts 261, 262, of relay 250, to the cathode of diode 263, the anode of which is connected to line CC, which also extends to the circuity in FIGURE 7.

Contact 235 of switch 232 is connected by wire 265, through contacts 266, 267, wire 268, contacts 269, 270, of relay 250 to the cathode of diode 271, the anode of which is also connected to line CC. Also, through wire 272, to the cathode of diode 273, to the output CA.

From the above, it will be apparent that on the count of thirty-five, both diodes 252, 273, will be blocked by the plus feed from cathodes 3 and 5. This means that the output CA will be removed from the ground wire 80, FIGURE 5, to which it was connected through the cathode resistors 79. Also, subsequently at the count of eightyfive, the same situation will prevail due to the fact that the switches 230, 231, are cross-wired with contact number 3 of switch 231 being connected to the number 8 cathode of tube 60. Accordingly, the line CA is blocked from ground at a selected count, such as thirty-five, and at a count fifty percent later by a count eighty-five. The output circuit CA and CC serve to control the offset selector shown in FIGURE 7 to shift the count rate so that the CA circuit will be controlled by the zero master timer count, instead of a different one.

Referring now to FIGURE 7, the pulses over the line 49 from the master timer disk 20 enter at the top left corner of the figure and, if not detoured to a lower level, proceed to the wire 281, FIGURE 5, to the grid of tube 282, which serves as an amplifier to feed the pulses to the units counter tube 61. The zero or ten cathode of tube 61 extends to the grid of the amplifier tube 283 for the counter tube 60. The plates of the tubes 282, 283, are supplied from wire 2 84, and the plates of the counter tubes are supplied from wire 285. As previously explained, the operating circuity for the counter tubes is conventional I and forms no part of this invention.

Wire 49 is connected to a resistor 287, which functions to limit transient currents. Protector P shunts out transient current that may pass the resistor, such as lightening transients. The Zener diode 288 does not pass anything below a certain voltage, as five volts. This to prevent pulse counting of noise and small AC voltages, resulting from differences in the various ground pickups which come from neutral conductors. The Zener diode 289 limits the potential to a predetermined voltage, as ten volts. The input pulse on wire 49 is in the order of between fifteen and twenty volts.

The section including tubes V1, V2 and V3, serve to omit pulses when the counter leads the master by one percent to fifty percent. This action is turned on by action of tube V6. The circuitry including tube V4 adds pulses when the counter lags the master by between one and fifty percent. V4 is actuated, or controlled, by V7. Tube V5 and the associated relay reset tubes V6 and V7, and make tubes V1 and V4 non-conductive, when the secondary controller is in step with the master timer. Relays SA and SC are operated from line 53 through the lines CA and CC, FIGURE 5, to effect synchronization between the master timer and the secondary controller.

To explain the operation of the offset control and resynchronizing circuitry, it will be assumed that the secondary traflic signal controller is to operate at zero offset. This means that the movable contacts of switches 230, 232, FIGURE 5, will be set on the zero fixed contacts connected to the zero cathodes of the counter tubes.

When a pulse is impressed on line 49 by the zero slot in dial 20 of the master timer, it is transferred by the counter to the diodes 252, 273, FIGURE 5. As previously explained, this results in blocking line CA to ground, through the resistors 79, connected to the zero cathodes of the counter tubes. This pulse is held by the counter tubes until the arrival of the next pulse. However, before the next pulse on wire 49 arrives, plus power is applied to line 53, FIGURE 3, by the slot 33 in disk 21 moving intermediate the lamp 37 and the photo cell 38. Wire 53, FIGURE 7, extends through diode 290, to relay SA, moving contact 291 into engagement with contact 292, putting a plus twenty volt feed through wire 293, to capacitor 294, the top of which is connected to diode 295. Normally, plus twenty volts is fed through resistor 296 to the junction 297 between the back to back diodes 295, 298. This plus supply, through diode 298, can find its way to ground through line CA, through diodes 252, 273, through the closed contacts of relays 245, 250, through switches 230, 231, 232, through the resistors 79, to ground line 80. Now, with the zero offset selected, diodes 295, 298, are blocked by the zero count from the tubes 60, 61, and the closing of relay SA, through line 53, the plus twenty is fed from the junction 297 to the diode 300, to the junction 301, through wire 303, to capacitor 304, to the grid of tube V5, causing the same to fire and close relay 305. Through its closed contacts 306, 307, the plates of tubes V6 and V7 are connected to ground wire 309. This assures de-ionization of the tubes and prevents any offset change. This amounts to an OK, or clearing check.

When slot 50 in disk 20 impresses a pulse on line 49, a plus feed is impressed on line 255, FIGURE 5, from switch 232, due to the cross-Wiring of switches 230, 231, placing a block on diode 263. At that time, the slot 35 in disk 22 causes a negative pulse to be placed on line 53 which, by the reversely positioned diode 311, establishes current through relay SC, to close the same. Closed contacts 312 supply plus twenty volts to capacitor 313, the top side of which delivers the plus pulse to the cathode of diode 314. Diodes 314, 315, are connected back to back at junction 316. A block has been placed on diode 315 by line CC. This resulting from the fact that the zero fixed contact of switch 231 is connected to contact number 5 of switch 230, by wire 317, FIGURE 5. A pulse now moves from plus twenty through resistor 318, FIG- URE 7, wire 319, diode 320, to the junction 301, again pulsing capacitor 304 to fire tube V5. This is the second clearing check showing that the secondary is in step with the master timer. It will be seen that the diodes 295, 298, and diodes 314, 315, form two AND circuits. Diodes 300, 320, make an OR circuit to make tube V5 responsive to either AND circuit.

Assume now that the counter is lagging behind the master so that its count is between fifty and ninety-nine-- for example, at sixty, at the time the zero slot in disk 20 sends out the zero pulse. It is to be kept in mind that the disks 2023, are all fixed to the shaft 23 and in the angular relationship shown in FIGURE 3, and the disks rotate in a counter-clockwise direction, Nothing affects the continued counting by the counter tubes 60, 61. When the counter reaches the zero count, the zero slot in disk 20 has since moved out of registration with the light source and cell 31. However, a slot, say number forty, in the disk causes the counters to give a count of zero. In other words, we are assuming the counter was forty counts behind the master timer. Shortly after the zero slot in disk 20 moved out of registration with the cell 31, the elongated slot 33 in disk 21 moved into registration with cell 38, so that a positive pulse was impressed on line 53, pulling in relay SA. However, the pulse impressed capacitor 294, through contacts 291, 292, rapidly dissipated. Accordingly, the blocking of line CA, on the count of zero by the counter, will not cause the plus twenty to pass to capacitor 304 to fire tube V5. This because with no charge on capacitor 294, the junction 297 is connected to ground wire 324, through resistor 325. However, the plus twenty volts will now charge capacitor 327. With relay SA held energized, the charge on capacitor 327 is impressed on the wire 328 by closed contacts 261, to capacitor 330, and to the grid of V7.

V7 is a gas tube and normally non-conducting. This results from the cathode current of tube V4, through resistor 331, holding the cathode of V7 slightly positive. The positive pulse impressed on the grid of V7 causes the tube to fire and the tube will maintain conduction until reset by relay 305 grounding the plate of V7.

Conduction by tube V7 changes the conduction of tube V4. Normally, tube V4 is conducting because plus twenty volts is impressed on the grid through the resistors 333, 334.

A pulser 335 includes a pair of contacts 336 periodically opened and closed by a constantly running motor 337. The frequency of the operation of the contacts 336 is much lower than the frequency of the pulses produced by the disk 20 of the master timer.

When tube V7 is conducting, it increases the drop across the resistor 331, with the result that the cathode of tube V4 is at about twenty volts. Line 338 provides ten volts negative to the pulser contacts 336. Accordingly, upon subsequent closures of the pulser contacts, ten volts negative is transferred by wires 340, 341, to capacitor 342, through resistor 334, to the grid of V4. This reduces the grid voltage to about plus ten volts, which is sufficient to lower the plate current of V4, so that the top of resistor 275 rises toward volts plus feed through the resistor 345, giving a positive pulse through capacitor 346, the pulse passing through wire 347 and upwardly through wire 348, diode 349, to the line 281 extending to the counter tubes 60, 61. The effect of this is that the counters receive an extra pulse upon each closure of the pulser contacts 336 and accordingly, the counter runs faster than normal and in doing so, is catching up with the master.

It will be apparent that the pulses from the pulser 335 are effective as long as the described circuitry is maintained, and that means until relay 305 closes and that, in turn, happens when the selected counted pulse is in step with the master zero pulse. Accordingly, the additional pulses from the pulser 335 may be sufficient to advance the counters in step with the master while the relay SA is held closed. On the other hand, energization of the line 53 by the slot 33 in disk 21 may be such as to overadvance the counter. Whether the counter is advanced far enough during this period to be synchronized with the master, or not far enough, or too far, depends of course on how far the counters were out of step with the master.

It will be apparent that if on the succeeding zero count, or fifty percent count, the count is exactly in step with the master, relay 305 closes, as described previously, and the counter continues on in synchronous operation with the master.

If, on the other hand, at a succeeding zero count, the counter may have become a little ahead of the master, say five percent, the CA feed from the zero count will coincide with a feed from the master on line 59. This is due to the fact that with the zero count appearing five percent ahead of the master, the slot 36 in disk 23 will be positioned intermediate the lamp 43 and the photo cell 44. With the zero count of the counter tubes 60, 61, being advanced five percent, line 53 will be energized with a negative feed due to the overlap of the slot 35 in disk 22 with slot 36 in disk 23. Accordingly, relay SC is closed. A wire 350 extends from contact 351 of relay SC, through Zener diode 352, to the coil of relay 353, the opposite side of which is connected by wire 354, to the ground line 355.

Plus ten volts is applied through diode 356, to the wire 350. With line CA blocked from ground at the zero count, wire 350 is connected through contacts 351, 357, of relay SC, and wire 358 to line CA. With the diode 252, 273, FIGURE 5, blocked at the zero count, the voltage on line CA now goes to plus twenty from the supply through resistance 296, diode 298, and accordingly the voltage rises to plus twenty on wire 350, increasing the charge on capacitor 375 by ten volts, which applies ten volts on the grid of tube V6 to make it conductive and this increase of voltage on wire 350, also pulls in relay 353. The Zener diode 352 serves to block the ten volts from diode 356 passing to the relay 353. The energized line 59 is connected to the armature 360' of relay 353 which is now moved into engagement with contact 361, transmitting power through line 362 to relay 364, the opposite side of which is connected to the ground 355. This results in the separation of contacts 365, 366, disconnecting line 49 from wire 367, which is normally connected to line 281, through contacts 368, 369, of a relay 370. The counters 60, 61, now dwell on the zero until the master sends out the zero pulse and immediately line 53 is switched from the negative supply to the positive supply from photocell 38, closing the relay 305, as previously described, and simultaneously slot 36 in disk 23 moves out of registration with the photocell 44, de-energizing line 59 and relay 364. The secondary controller and master timer are now again in step.

It will now be assumed that the counter has reached the zero count between ten and fifty percent adhead of the master, say twenty-five percent. This means that at the zero count from the counter tubes, the slot 33 in disk 21 would be positioned downwardly, the slot 35 in disk 22 would be positioned upwardly and likewise, the slot 36 in disk 23 would be positioned clockwise from that shown in FIGURE 3, ninety degrees. Accordingly, with slot 35 in registration with photo cell 41, negative power would be impressed on conductor 53 and relay SC would be closed at the time of the zero count from the counter tubes. Also, as previously explained, at that zero count, line CA will be blocked from ground by the plus pulse on the diodes 252, 273, FIGURE 5. The plus to the line 350 will rise to fire tube V6. This same situation prevailed in connection with the explanation above of the dwell period functioning. However, in this instance, the slot 36 is not positioned to actuate the photo cell 44, so there is no power on line 59 and accordingly, the closure of relay 353 does not bring about the closure of relay 364.

With the plus pulse on the grid of tube V6, the tube is made conductive. The circuitry arrangement between tubes V6 and V1 is similar to that between V7 and tube V4. In other words, when tube V6 is made conductive, the cathode of tube V1 rises to about plus twenty volts, through line 376. The grid of V1 is supplied with twenty volts positive current through resistors 377, 378, and V1 will continue to be conductive until the plate of V6 is grounded by energization of relay 305, or by the reduction of voltage on the grid of V1, which is brought about by the closure of the pulser contacts 336. When V1 is rendered non-conductive, its plate goes positive from the one hundred fifty volt plus supply, through resistor 380. The pulse is transmitted through capacitor 381, resistor 382, to the starting anode of the tube V2, causing it to fire. With V2 conducting, the relay 370 is energized, moving the contact 368 into engagement with the contact 383. This disconnects the counter pulse line 367 from the line 281. The next pulse from 367 is applied to the grid of tube V3, turning the tube on and closing relay 387 connected in its plate circuit. The resulting movement of contact 388 out of engagement with contact 389, removes the plus supply to the plate of tube V2, rendering it non-conductive and causing relay 370 to drop out. By this time, the pulse from 367 has been dissipated and has not been transmitted to the counter. This process is repeated by successive closures of the pulser contacts 336 until the counter tubes 60, 61, reach zero, not more than ten percent ahead of the master zero pulse, at which time the slot 36 in disk 23 has effected operation of the photo cell 44, so that power is supplied to the line 59 to hold relay 364 energized until the zero pulse comes from the master.

What I claim is:

1. A traffic signaling system for a multiplicity of intersections comprising:

(a) a cyclical master timer operable during each cycle of operation to produce a zero control pulse, N equally-spaced stepping pulses, and phase control potentials respectively manifestive of the two halves of the master timer cycle on each of a plurality of output lines;

(b) a single cyclical pulse counter associated with the signal controller at each intersection, and operable to advance one count for each stepping pulse received thereby, and to manifest all counts between zero and N counts;

(c) first settable means at each controller for predetermining the count in said counter at which each one of a series of trafiic movements is intended to begin;

(d) means interconnecting said first settable means and said counter, and operable responsive to a coincidence between the respective preset counts and the count manifested in said counter for activating each respective one of the sequential traffic movements;

(e) second settable means at each controller for presetting the desired phase relationship, otfst, of the cycle of said counter with respect to the cycle of said master timer;

(f) a communication link connecting the outputs from said master timer with the controller at each intersection and operable to transmit said zero control pulse, said stepping pulses, and said phase control potentials;

(g) means interconnecting said counting means and said second settable means for producing a unique signal only when the count in said counter equals the preset value in said second settable means;

(h) normally active means connecting said stepping pulses to said counter to advance the count in said counter;

(i) means responsive to the lack of said unique signal and to one of said phase potentials for rendering said normally active means inactive to transmit stepping pulses to said counter when the counter leads the preset phase relationship;

(j) means responsive to the lack of said unique signal and to the second of said phase potentials for producing a control potential to advance the counter at an accelerated rate; and

(k) a pulse-producing means operatively connected to said counter by said last-named control potential for advancing the counter; whereby said counter is maintained in the proper phase relationship and in synchronism with said master timer and provides the 1 1 1 2 sequence of traflic movement controls at the requisite whereby the phase and synchronism of the counter is preset times in the cycle. checked twice during each cycle.

2. The traffic signaling system of claim 1 wherein said master timer is adapted to produce a variable cycle length.

3. The traffic signaling system of claim 1 wherein said UNITED STATES PATENTS References Cited first settable means comprises a plugboard into which a 5 3 252133 5/1966 Auer 340 40 plurality Of diiferent time COUIIIS for initiation Of thB Same 3 25 134 5 19 6 Auer 340 35 trafiic movement may be plugged, and means for remotely 3305828 2/1967 Auer 340 40 selecting one of the plurality of preplugged counts for control. 10 THOMAS B. HABECKER, Primary Examiner 4. The traflic signaling system of claim 1 wherein said second settable means includes a true count manifestation C XR and a manifestation of N/2 plus the true manifestation -166

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