US2624793A - Traffic signaling system and apparatus - Google Patents

Description

Jan. 6, 1953 F. A. PEARSON 2,624,793

TRAFFIC SIGNALING SYSTEM AND APPARATUS Filed Feb. 21, 1949 4 Sheets-Sheet 1 l lllllll ihlfliiiiiimmwal IN VEN TOR. gfA/VK ARTHUR PEARSON ATTORNEY Jan. 6, 1953 F. A. PEARSON 2,624,793

TRAFFIC SIGNALING SYSTEM AND APPARATUS Filed Feb. 21. 1949 4 Sheets-Sheet 2 INVENTOR. FRA/VK ARTHUR PEARSO/V BY ATTORNEY Jan. 6; 1953 F. A. PEARSON TRAFFIC SIGNALING SYSTEM AND APPARATUS 4 Sheets-Sheet 3 Filed Feb. 21', 1949 To Of/rer Gqnfro/lers In Me System L I ATTORNEY Patented Jan. 6, 1953 TRAFFIC SIGNALING SYSTEM AND APPARATUS Frank Arthur Pearson, Moline, 11]., assignor to Eagle'signal Corporation, Moline, 111., a corporation of Massachusetts Application February 21, 1949, Serial No. 77,528

14 Claims. 11

This invention relates to signaling systems and apparatus and more particularly to apparatus for providing diiferent schedules of traffic control at difierent times of the day.

On main thoroughfares, it is desirable. to provide a traffic control system that will permit a car starting at one end of the main street to travel at a designated speed and be given a green Go signal at each intersection. This is termed a progressive traffic control system as the main street green signalsat each intersection are timed to come On as the vehicle progresses down the street at a specified speed.

The equipment used to provide this type of traffic control normally consists of a local controller at each street intersection which is synchronized with a single master timer. The local controller has a step switch which operates the signals in the proper sequence. A motor driven cycle dial with adjustable levers operates a set of switches momentarily to advance the step switch from one position to the next. The time that the signals remain in each condition is determined by the positioning of the dial levers. The signals go through a complete cycle in the time required for the cycle dial to make one revolution. The cycle dial on each controller is synchronized by the master timer so that the cycle .dial at each intersection. rotates according to a predetermined phase relation with each other and thus provides progressive movementof traffic along the main street.

This invention pertains mainly to above mentionedtype of traffic. controllers except having multiple cycle dials any one of which may be selected to advance the step switch. Multiple cycle dials permit setting adifferent timing program on each to handle different trafiic conditions most emciently.

For each tramc condition, the time cycle and percentage of red and green indications required for each intersection can be determined by making a time-space chart. The intersections are located on the chart according to their spacing in feet. A group of vehicles progressing down the street is represented by two parallel lines drawn diagonally across the chart. The slope of the line represents the speed of vehicles in feet per second. This chart determines the number of seconds which must occur from a given reference point to the start of the green period at each intersection. A convenient reference point is the synchronizing point of the master controller. The term offset is used herein as the percentage of the total cycle that the start 2 ofthe main street green at the intersection is shifted from a 0 reference point in the master controller cycle.

For average conditions, tramc will be approximately the same in each direction along the main street, and the cross street trafiic will be an appreciable percentage of the total. ,For'these conditions it is advantageous to use a short signal cycle to .eliminatelong waiting periods on either street. To allow for progression of an equal volume of traific in each direction, the offsets should be determined from the time-space chart. The time cycle, percentage division and offset are set on dial #1 of the controllers at each intersection.

Heavy inbound trafiic occurs during certain times of the day such as the hours just berore the stores and offices open. This traffic moves more slowly because many are seeking parking places or turning oii into side streets. A timespace graph made for this condition is based upon a slower speed and a wider inbound traffic band. A slower time cycle and larger percentage oi the cycle for main street green would be used. The schedule thusdetermined is set on a second cycle dial of each controller which would be operative at periods of heavy inbound traflic. The time cycle, percentage division, and ofiset may all be dliferent than the schedule on dial #1. Similarly, outbound traflic will be heavy just after the stores and ofiices close. The schedule determined by a time-space graph can be set on a dial #3.

In many cases where the intersections are evenly spaced, the same percentage division of a cycle for outgoing and ingoing tra'flic can be used, except a different ofiset may bev required. My controller provides a selection of oiisets for each dial. The same dial can be used for both outgoing and ingoing traflic in these cases. The other dial can then be used to provide a greater percentage green for the cross street trafiic and used during periods when cross trafiic is. heavier than normal.

Previous types of multi-dial cont-rollers have not been provided with a satisfactory means of transferring the step switch control from one dial to the other. If this-transfer is made without proper synchronization, the signals may remain in one position for an extended period which may be under some circumstances as long as the main street green interval. This causes confusion and unnecessary interruption of traific.

One object is to provide means whereby a minimum disturbance will result in the movement of traflic at an intersection when transferring from one schedule to another. This makes the transfer possible only when the cycle dials and step switch are in a selected position.

Another object of my invention is to provide an m'lproved system of traffic control in which each oral of a multi-oial controller is driven by a separate motor at a selected. speed, anyone of which may be selected to control the signal cycle.

Another object is to keep the signal control step switch in synchronism with the cycle dial when transferring from one cycle dial to another.

Another ob ect is to provide a selection of offsets for each cycle dial and a simple method of selection from a remote point.

Another object is to provide a step switch mechanism with a switch to provide a momentary impulse for eifecting transfer from one dial to another when the step switch is in a predetermined position.

Another object is to transfer from normal Stop and U indications to flashing night light only when the signals are in a predetermined position.

Reference is made to the following description and the accompanying drawings for a better understanding of my invention together with other and further objects thereof.

Referring to the drawings,

Fig. 1 illustrates a front view of the controller built in accordance with my invention. The second dial is removed and part of the front plate cut away to show the contact mechanism. Space for the third dial is shown. Part of the bottom panel is cut away to show the location of the step switch.

Fig. 2 is a side view of a cycle dial unit.

Fig. 3 is a schematic view of the step switch.

Figs. 4, 5, 6, are detail views of the transfer cam and contact on the step switch.

Fig. '7 is a side view of the transfer relay.

Fig. 8 is a schematic across-the-line diagram of the electrical circuit of the master timer and a local intersection controller.

Fig. 9 is an exploded view of the cycle dial.

Fig. 10 is an exploded view of the cycle dial cam shaft and offset levers.

Referring to the drawings in detail, Fig. 1 illustrates a front view of the controller housing I having a, front panel 2 on which are mounted toggle switches 3, 4, and 5, with a legend plate 6. A suitable ledge is provided on the top edge of plate 2 to support three cycle dial units which are held in position by thumb screws 8. Step switch 400 is mounted behind the front panel 2 under the cycle dial units.

The three cycle dial units are identical to each other. Figs. 1, 2, 9 and 10 illustrate the construction in detail with the parts numbered in the I00 series. To distinguish between the three cycle dial units in Fig. 8, all parts marked with a number in the I00 series in this figure are a part of the first cycle dial unit. All parts marked with a number in the 200 and 303 series belong to the second and the third cycle dial units respectively. The last two digits of all numbers in the 200 and 300 series refer to the same parts in Figs. 1, 2, 9 and 10 having the same last two digits. The cycle dial units may also be termed timers as they provide impulses according to a preset timed schedule to advance shaft 420.

The cycle dial unit shown in Fig. 2 consists of a front plate I20 and a back plate I2I held parallel by posts I22 and an insulating contact block I23. A flexible contact leaf IIl la is mounted on the top of contact block I23. Another flexible contact leaf Iueo is mounted on the bottom of contact block I23. Each of the above contact leaves has a contact point attached to one end. 'lhe leaves are formed so the contacts on each spring are normally separated from each other. l'he above pair or contact leaves comprise a switch hereinafter termed switch me. An insulating finger I06 pivoted at one end on shaft 101 is located under lea: ludo. Snail; Ili'I is carried by hearing holes in plates I20 and IZI. Finger we is held in proper alignment with the contact leaf I340 by suitable s acers and collars assembled on the shaft lo I. rresslng upward on finger lilo causes it to press bottom contact leaf |u4b upward to make contact with a top leaf Iuca thus completing a circuit through the switch. The Weight of linger lot causes it to drop back to its normal pOSlUJ-OD. where it lays agalnst a post IIIB between plates IZIJ and Ill. Four additional pairs of leaves mounted on block In comprise switches IIII, I32, I03, and I05 each actuated by a finger I03.

Plate IZI has a long sleeve bearing I24, best shown in Fig. 1e, riveted thereto which carries a oial shaft I25. Attached to shaft Izai is a cup shaped drum I26 counterbored IIOm one end to fit over part of bearing I24 and which has an outwardly projecting flange I21. Assembled against hange I2! is an arm II3. Against arm H3 is a spring washer II l and a sleeve II5 fastened to orum I26 with a set screw. Another set of these parts, consisting of an arm II2, Washer I14, and another sleeve II5 is assembled on drum I26 in a similar manner. An arm III assembled rigidly on a collar H6 is next assembled on drum I26 and secured thereto with a set screw. Each of arms III, H2, and H3 has an index line in an identical position. The two sleeves I I5 are each calibrated in percent around their periphery and are positioned when assembled so that their 0 calibration is in alignment with the index line on arm III. Arms III, H2, and H3 are positioned to actuate fingers I36 and close switches IGI, I02, and I03 respectively for a brief part of each revolution.

Arms I I2 and I I3 can be shifted or offset from 0 by sliding them around drum I25. They will be held in position by spring washers I I4 and the amount of offset from U will be indicated by the position of the index marks on arms H2 and H3 in relation to calibrated sleeves II5.

A dial and dial lever assembly, best shown in Fig. 9, is carried by the shaft I25 in front of drum I225. This consists of a hub I28 having an outwardly projecting flange at its rear end with the opposite end threaded and two keyways on its outside periphery. The inside of hub I28 is a free running fit on shaft I25. A dial lever I32 is assembled on the hub I28 against its flange. Next is assembled a flat spring washer I29 having two projections which fit into the keyways of hub I28. Dial levers I3I, I36, I35, I34, and I33 are assembled on hub I28 with spring washers I 29 between each pair of levers. Spacer washers I33 are used to fill the extra space on the hub I28 as this hub is of sufficient length to receive a larger number of dial levers if necessary. Dial I3? is assembled after the last lever and has two projections which fit into the keyway in hub I28 to prevent it from turning relative thereto. Hexnut I08 is then screwed to hub I28 with wrench I38. With nut I38 loosened part of a turn, dial levers I3I through I 36 are loose and can be moved around to any point of the dial. Tightening nut I08 locks them in a fixed. relationship; with. dial I31- Dial-lever I32 has an inwardly projecting portion I32a positioned so that it actuates finger I06 and closes switch. I05 once upon each revolution of the dial but which does not close switch I04. Dial lever I32 is the only lever which will close switch I05. This lever also has an outwardly extending projection I325 which extends approximately to the back surface of the dial I31 and then extends radially therefrom and on which an identifying numeral 2 is stamped. Each of dial levers I3I, I33, I34, I35, and I36 has a shorter inwardly projecting portion which is inalignment to actuatefinger I06 and close switch I94. Their outwardly projecting portions are stamped n1, 3, 4, "5), and 6 respectively- The dial I31 and thedial levers described above comprise an assembly on hub I28 which is free to rotate on shaft I25. The manner of locking dial I31 to shaft I will now be described. A hub I39 with a dial I40 is mounted on end of shaft I25 and secured by a set screw. The outer periphery of dial I40 has gear teeth meshed with a pinion I4I. This pinion is carried by a-threaded stud I42 on dial I31 and which may be locked thereon by thumbnut I43. Therefore dial I31 can be rotated freely about shaft I25 as long as pinion I4I turns freely. Tightening thumbnut I43 locks pinion MI and dial I31 is locked to dial I40 and shaft I25. Dial I40 is calibrated in percent and its 0 is positioned to be under index mark I44, shown in Fig. l, at the point at which arm II I closes switch l0i. This is definedas the 0 position of shaft I25.

Shaft I25 extends beyond plate I2I and has a collar I45 pressed on it. A cycle gear I45 is mounted on the shaft and clamped against collar I45 with a thumnut I41. Cycle gear I46 is removable so that different size gears can be installed to rotate dial I31 at selected speeds. A constant speed motor I59 having a pinion I5I drives gear I45. Motor I50 has a stud I52 attach'ed thereto with a groove in the outer end which engages and slides in a vertical slot in plate I2I. A stud I53 attached to the lower end of the mounting plate has a screw I54 extending through the stud with a thumbnut I55 on the opposite side of the plate. Tightening thumbnut I55 clamps plate I2I between head of screw I54 and stud I53. This mounting arrangement allows motor I50to be positioned vertically to mesh its drive pinion I5i with different size cycle gears I46.

The time cycle provided by each size gear is indicated on a calibrated scale I56 by a pointer I51 attached to shaft I58. Scale I55 is mounted on front plate I20. Shaft I58 extends through plate I2] and on the end of this is secured an arm I59 which rides under stud I52.

A spring I around shaft I58 has one end held stationary by screw IGI and'the other end secured to collar I62 attached with set screws toshaft I59. Spring I50 normally holds arm I59 upward against stud I52 as the motor is moved into position. Therefore, the positioning of motor as determined by the size gear I45 used, determines how far arm I59 as depressed, which likewise determines the position of pointer I51 on scale I56.

Details of motor I58 are shown in my pending application No. 759,091, now Patent No. 2,597,369.

Briefly, energizing coils I 55 drives disc I66 at a constant speed. Disc I66is geared to drive pinion I5I founR. P. M. through a solenoid operated clutch: operated bycoil I61.. Whencoil I51 is energized, the clutch; disengages disc I66 from pinion I5I allowing the disc to continue rotating .I 61 terminate in a plug IE8. Wires from switches I0i through Hi5 terminate in a plug I69. Three cycle dial units as described above are assembled into the controller housing and plugs I68 and I69 plugged into mating receptacles inside the housing.

The step switch assembly 400 shown in Fig. 3 and mounted in controller housing I below the cycle dial units consists of a shaft 420 with suitable bearing supports upon each end. Attached to the shaft 420 is a series of cams 40! through 409 (see Fig. 8) and two ratchet wheels 42I and 422 (Figs. 1 and 8) each having 12 notches. Free to oscillate upon shaft 420 is a laminated armature 423 (Fig. 3) consisting of laminations riveted between side plates 425 and 426. The C-shaped laminations 421 are the field poles for the armature which are magnetized by coil 4I0. Two brackets 428 are attached to the top sides of the laminatiohs and project past the front of the laminations to hold a rubber bumper 429 which is attached with 2 screws 430. On the bottom side of the laminations, an angle bracket 43I is securely bolted. At the back side and near the bottom of lamlnations 421, a stud carries pawl 433 in lateral alignment with ratchet 42L A spring 434, attached between the pawl and a screw 435 in the laminations 421, causes the pawl 433 to be biased toward engagement with ratchet 42 I.

The armature side plates 425 and 426 have a projecting portion which extends toward the front of the assembly. A pawl 435 is secured in lateral alignment with ratchet 422. A spring 435 keeps the end of pawl 436 in engagement with the ratchet 422. Attached between the projecting portions of the side plates 425 and 426 is a weight 439. A rod 449 projects from the weight 439 and the armature side plates. The top and bottom portion of the armature laminations423 are each spiral shaped so that when "the weight 439 holds the armature as shown in Fig. 3, approximatelya inch air gap exists between the field pole and the front of the spiral armature. When the coil M0 is energized, the magnetic lines of force, endeavoring to establish a magnetic path of minimum reluctance, rotate the armature and raise the weight 439 until it strikes the rubber bumper 429. At this point there is only a few thousandths air gap between the armature and field laminations. This movement is sufficient to cause pawl 436 to move slightly past the next tooth in ratchet 422. Pawl 433 prevents the shaft 429 from rotating in the upward direction with the armature. When coil 4I0 is deenergized, weight 439 falls downward and pawl 435 causes the shaft 420 to move forward the angular distance equal to one ratchet tooth. When pawl 436 hits the angle plate 43I, the armature stops and the shaft is prevented from moving farther because of the wedging action of pawl 435 between the angle plate 43I and ratchet 422.

Associated with the cam 40I is an L-shaped contact finger 4H which is pivotally mounted on a terminal lug 44I secured to an insulating base 7 panel 450. A screw 442 going through the panel 459 and lug 44! holds a spring M3 between nut M4 and contact finger M This spring presses contact finger H! downward so that a contact point Mia attached to the finger comes into engagement with contact lllb on a stationary bus bar 445. The end of finger 4!! rides on cam 40! and is lowered and raised as the cam is rotated according to cut out sections of the cam.

Contact finger H2 operates in a similar manner except it is controlled by cam 482 and in addition by a cam 446 which oscillates about shaft 420. Cam 4% has a projecting portion with an opening 447 through which rod 440 projects. When coil Mil is energized to move the armature upward, rod i lii moves cam 448 upward. Deenergizing coil ME! releases the armature and cam 4% drops to its normal position. Cam 492 has a cut out section or notch, which permits contact finger 452 to close its contact if the cam is positioned as shown in Fig. 4. However, the cam M6 prevents the finger M2 from falling into the notch in cam cs2. When coil Mil is energized, cam 356 is rotated and the raised portion of the cam is moved away from the contact finger M2 allowing it to close as shown in Fig. 5. When coil ilo is deenergized, cam 4% drops and cam 492 is also rotated one step so its notch is no longer presented to linger H2. Thus the next five succeeding oscillations of cam M6 will not lower finger 652 as it is held by cam 492 as shown in Fig. 6.

Therefore in the position of shaft 420 corresponding to the cut out portion of cam G02, switch M2 will close when coil 410 is energized and will open when the coil is deenergized. This switch provides an impulse to release the transfer relays hereinafter described. The other cams 493 thru W9 operate fingers H3 thru M9 respectively according to the cut out portions on their edges. Ratchets 422i and 422 have 12 notches for the particular controller being described. This is a number standardized upon for commercial convenience in providing various signal combinations. Only 6 of the 12 step switch positions are used for the signal display herein described so that the cam contour of each cam between 0 and 180 is duplicated between 180 and 360. The cams are cut to close the switches in each of six positions shown in the table below where X indicates a switch closed and 0 indicates a switch open.

Position of shaft 420 Switch MOOOONNOO MOOOOMOON MOOOMOOOM OONNOOOOM OQNNOOOON m ONONOOOMM 8 524. A pin 5534a carried by armature 5M latches armature 562 in either its retracted position away from coil 58! or in its attracted position. To close the circuit to contact 506, it is necessary to energize coil 50! and also coil 5B3. Coil 503 has only to be energized momentarily to allow the armature 502 to be unlatched. Releasing armature 58 3 when armature 502 is pulled forward will cause pin 55% to latch armature EliZ closed. Coil 583 will therefore have to be energized momentarily to release armature 502 after coil 55! is deenergized. Relay 500 has 2 additional sets of contacts mounted on armature 502 identical to 523-505-405 providing the relay with 3 pole double throw switch contacts. Another transfer relay iiflil shown in the diagram in Fig. 8 is identical to that above.

The controller housing contains in addition to the above parts, a three pole double throw relay me with coil it! and contacts 102 through 'ili'i. It also contains a motor driven flasher consisting of a motor 15! driving cam 152 which closes and opens switch 753 approximately 60 times per minute.

The electrical connections for the component parts of a controller and set of signals is shown in Fig. 8 together with a master supervisory controller.

The master controller has 3 motors, 86!, 802,

833. These motors run continuously being connected to line 364 by wire 8% and to line 805 by wire 8M. Motor 2% drives a cam 82! through a set of gears 8! 1. Cam 82! has a series of projections which actuate switch 83! momentarily as the cam rotates. Two projections 82m and 825d on the cam are exactly apart. Projections 82), 82M, and 82ie are spaced so no two are exactly 180 apart. The gears 8!! are selected so that cam 82i rotates 180 in the same period of time as dial l3l rotates 360.

Likewise, motor 8&2 drives a cam 822 (identical to cam 82!) through gears 8!2 at a speed one half that of dial 237. Cam 822 actuates contact 232. Motor 8% drives a cam 823 (identical to cam 82E) through gears M3 at a speed half that of dial 33?. Cam 823 actuates switch 833. One side of switches 83!, 832, 833 is connected to line 865 by wire Wire 8M connects the other side of switch 83! to one point of a position switch 825. Wire 855 connects the other side of switch 832 to a second point on switch 625 and wire 8|8 connects the other side of switch 833 to a third point on switch 825. A switch arm 824 on switch 825 completes the circuit from wires 8M, 8|6, or Bill to wire 820 as selected. Wire 828 connects switch arm 824 to switch arm 82! which can be set to connect wire 82!] to a selected one of wires 85!, 842, or 843.

Wires 85! thru 34'! comprise a cable which connects the master timer with the controllers at each street intersection. Wire 8% is connected to position two and wire 8 35 to position three of a separate pole of switch 825. A switch arm 826 connects either wire 8 34 to line 8% in position 2 or wire 845 to line 895 in position 3. Wire 846 is connected to switch 8% which completes the circuit to line see when the switch is closed.

A set of traflic signals consisting of a green signal it, yellow signal !5, and red signal [6 indioate Go, Caution, and Stop respectively to tramc on main street. A similar set of signals l1, 8, and !9 indicate Go, Caution, and Stop to cross street traffic. Signals l4, l6, H, and !8 are connected to switches M4, M6, M1, and M8 by wires 24, 26, 21, and 28 respectively. signal I'is' connected to anormally closed contact 102 by wire 25. A contact 102 is connected to switch 415 by wire 33. Signal I9 is connected to normally closed relay contact 164. Wire 3| connects contact 16s to switch 419.

The other side of switches 4M through ife is a bus bar 449 from which the circuit is completed to line 34 through wire 32, relay contact 1%, wire 33, toggle switch 3 and wire 43. The other side of signals i4 through I9 is connected to line by wire 38. Thus with toggle switch 3 closed and relay 13s deenergized, step switch 483 will energize a certain combination of signals in each position of shaft 429 according to the contour of cams 434 through 439. As shaft 520 is advanced periodically through its six positions, the signals will operate through a complete signal cycle.

The manner in which the ste switch is periodically advanced by cycle dial unit I69 will now be described. Motor I53 is energized to rotate dial I31 by the circuit from line 34, through toggle switch 5, wire 31, normally closed relay contact '639, wire 33, normally closed relay contact 539,

wire -8. motor Iii wire 38 to the other line Wire 35. Dial levers I3I, I33, I34, I3 and I33 close switch Hi4 momentarily as dial I31 rotates. Coil 4!!! is actuated to advance shaft 423 over the cirsuit from line 34 through wire 4%, switch 4| 5, wire '4 I ,switch I04, wire 42, normally closed relay contact 5%, wire 43, normally closed relay contact I535, wire 44., switch 4, wire 45, coil 4H3, wire 46 to line 35. The time between advances of shaft 423 is therefore determined by the speed of dial I31 and the angular distance between the dial levers.

When shaft 42!! advances to its number 1 posi- 3, wire normally closed relay c ntact 1%, wire 32, switch I35, wire 42, contact 505, wire 43, contact 535, wire .4, switch 4, wire 45, to coil 4H). Since dial lever I32is theonly one which closes switch I35, shaft 429 must always be advanced out of its number 1 pos tion by dial lever I32 and thus start each revolution properly synchronized with dial I31.

O ening the shutdown to gle sw tch 3 or energzine coil 'FIlI which opens contact 133, interrupts the circuit to switch h s but does not interrupt the circuit to switch I34 Shaft 429 will cont nue to advance to position number 1 where where switch M4 is closed. Therefore u on reclosin swit h to res rre n r al si nal operation; shaft 42? will he in o it on 1 and the'first signal ind cation will be the main street green.

If shaft 423 is out of step with dial I31, shaft 428 will stay in its number 1 position with the ma n street green On until dial lever I32 closes switch Hi5 to start shaft 423 in its synchronized relationship. In this way the waiting period of shaft 423 for synchronizat on always occurs in the main street green interval to give the Go signal for this extra time to the street having the largest traffic volume.

The supervision of each controller from the master station will now be described. When switch arm 325 of switch 325 is in position one to select dial I31, it does not complete any electrical circuit and relay coils Elll and GSI are deenergized. When both of these coils are deenergized, motor I53 runs and switches I04 and I85 are effective to actuate coil 4IIl over the circuit previously described.

*Switcharm 824 of switch 825 completes a circuit from line 834, wire 835, switch 83I. wire 8", switch arm 824, wire 8213, switch arm 821, wire 84L switch IIJI, wire 43, through clutch coil I61, wire 59, contact 581, wire 5|, contact 601, wire 52, wire 841 to line 805. Switch 83I is normally closed so that closing of switch IBI by arm III will energize coil I61. This disengages the clutch and stops dial I31. Dial I31 remains stopped until cam 82! opens switch 831. This deenergizes coil I61 allowing clutch to reengage. Cam 82I holds switch 83I open slightly longer than arm III holds switch IdI closed. Therefore switch IIlI opens before 83! closes and clutch coil I61 remains deenergized for another complete revolution of dial I31. Cam 82I is geared to rotate from point 82m to 82Id in exactly the same time required for dial I31 to make one revolution. Therefore if point 82Ia opens switch 83I to restart dial I31, point 82Id will reopen switch 83I at exactly the same time that arm III recloses switch IBI. Coil I61 will not be energized and dial I 31 will continue to rotate in a fixed relationship with cam 82I without stopping. All the other controllers in the system will likewise be synchronized with cam 82I.

Should the synchronized relationship not exist, closing of switch IIlI stops dial I31. So that dial I31 does not remain stopped for a complete signal cycle waiting for projection 82m or 82Id to open switch 83I, which would unnecessarily delay traffic on the cross street, I provide additional projections 32Ib, 82Ic, and 82Ie on cam 32L Any of these projections opening switch 83! will restart dial I31. However, since there are no projections across from these, dial I31 will be stopped upon the completion of the next cycle and will be started by a different projection on cam 82L Within a few cvcles. either projection 82Ia or 82Id will start dial I31 and the synchronized relationship will be maintained for succeeding cycles.

The 0 point of dial I48 will normally be under index mark I44 each time 82 Ia or 82Id opens switch 33L This is true for the dials of each controller connected to the system. The 0 point on dial I3 can be sh fted to anv relationship with the 0 on dial I43 and locked. The 0 point of dials I31 at each intersect on can be set for a predetermined offset from the 3 on dial I43. .Dial lever vI3I is set at 0 on dial I31 and determines the start of main street green. Thus the main street green signs come On at successive intersections alon -the street according to the offset between dials I 3! and I40 of the respective controllers. The coordinated start of the green signal periods provides for a progressive movement of trafiic.

A selection of two additional offsets for dial I31 is provided by switches I02 and I03 and their actuating arms H2 and H3. When switch arm 321 is moved to its second position, the circuit from wire 820 is established to coil I61 through wire 842 and switch I32. Therefore positioning arm II2 establishes a new synchronizing position of dial I31 with cam 82I. For example, if arm II2 is set at 15%, it will close switch I32 when 15 on dial I 48 is under index mark I 14. The start of the main street green..(determined by 0 on dial I31 at which arm I3I is set) is thus shifted 15% of a revolution of .dial I31 in its synchronized relationship with projections 22m, and 82151 on cam 82I. In a similar manner, moving switch arm 821 to wire 843 completes the circuit to coil I61 through switch 103.

Arm I I3 actuating this switch can be set for a selected third offset position.

Switch 825 selects which one of cycled dial units I00, 200, or 300 is to actuate coil 4H0. In the second position of switch 825, acircuit is completed from line 804, arm 82 6, wire 8-44, relay coil 50L wire 52, wire 841 to line 805. Coil 50! cannot immediately actuate armature 582 which is lacthed open by the pin on armature 584. When the main street red signal is On (position 6 of shaft 420) cam 402 is positioned as shown in Figure 4 but switch 412 is held open by cam 446. When dial lever l3! closes switch 154 to energize coil 410, cam 44B is raised to position shown in Fig. 5 and switch 4|2 closes. A circuit is now completed from line 34, wire 40, bus bar 445, switch 4l2, wire 452, coil 503, wire 35 to line 35. Armature 504 withdraws pin from armature 502 which now opens contact 505, 501,505 and closes contacts 506, 568, and 5m.

Opening contacts 508 stops motor 150 at the point where arm [3] holds switch I84 closed. In some cases, the motor may coast far enough to allow arm l3! to open contact m4. Closing contact 5|0 starts motor 250. This motor will have stoppedfrom its previous operation with its dial arm 23! either holding switch 204 closed or with arm 23! coasted slightly past its closing point. If switch 284 is closed, coil 4!!! will remain energized without advancing shaft 420 as the opening of contact 505 and closing of contact 506 is much faster than required for the heavier armature of coil 4 l to release. When motor 250 drives dial far enough for arm 23! to release switch 204, coil M0 is denergized and shaft 428 advances to its next position. If switch 204 is open when contact 506 closes. coil M0 will be deenergized immediately and advance shaft 425 to its next position. In either case, dial lever 232 will close switch 205 as the next operation and advance shaft 420 to its number two position in the same manner as it would have been advanced by dial lever I32. Transfer has been made from one dial to the next in this way with cam shaft 420 remaining in its proper relationship-with the dial levers.

Opening contact 501 and closing contact 508 transfers the synchronizing circuit from clutch coil I01 to 251. One of switches 20l, 202 and 203, as selected by the position of switch arm 821, now synchronizes dial 231 with cam 822 of the master timer in the same manner as dial E31 was synchronized with cam 82!. The dial 231 is geared to rotate one revolution during one half revolution of cam 822. Dial 231 will ordinarily be set for a different speed of rotation and its dial levers set for a different trafiic schedule.

Dial 331 is selected by moving switch 825 to position 3. Relay coil GM is energized but armature 602 is held open by the pin on armature 804. When shaft 420 is in its number six position and dial arm 23! close switch 204 to energize coil 4| 0, switch 4| 2 closes to energize coil 603. Arma ture 604 withdraws the pin and releases armature 602. Contacts 605, 501, 609 then open and 606, 608, and (H0 close. Switch arm 824 transfers the synchronizing circuit to switch 833 and cam 823. Dial 331 is geared to turn one revolu tion during one half revolution of cam 823.

When switch 825 is returned to its first position, coil 60! will be deenergized but pin on armature 604 will hold armature 602 in its attracted position. When shaft 420 reaches its number six position, switch M2 is closed when dial arm 33! closes switch 304 to energize coil M0. Relay coil 003 is energized which removes the pin from behind armature 602 allowing relay to release. Transfer can thus be made to any dial by positioning switch 825, but the actual transfer does not occur until the dial arm i3l (or 231 or 33!) actuates its switch I04 (or 204 or 304) and shaft 420 is in position six. The one dial then stops and the other dial starts with the step switch properly synchronized with the new dial.

When there is little traffic at night, the signal display may be stopped and one of the signals on each street flashed as a caution signal. A switch 848 is provided for this purpose which, when closed, establishes a circuit from line 804 through switch 848, wire 845, switch 413, wire 448, coil 10!, wire 841 to line 805. Coil 10! can be energized only when shaft 420 is in its number one position where switch M3 is closed. This insures completion of the signal cycle before the signals are transferred to flashing. When transferred back to normal operation, shaft 428 will be in position number one to give main street the Go signal first. Energizing coil 10] opens contacts 102, 104, 105, and closes contacts 103, 105, and 101. Motor 15! starts which drives cam 152 to close switch 153 approximately sixty times a minute. Switch 153 flashes the main street yellow light l5 and the cross street red light 18.

Switches 825, 321, and 848 are shown as manual switches but can be replaced with automatic time switches to operate them according to a preset schedule without departin from this invention. If the controller is to be operated independently of the master controller and not as part of a system, switches 825 and 848 could be located at the controller. In this case, wires 84L 842, and 843 would not be required. No synchronization would be required and coils I51, 201,

and 351 could be omitted.

Switch 4 may be turned to hand operation to operate the signals by pressing hand control button 8|. Each closing and opening of switch 61 advances shaft 420 one position. This permits a police officer to operate the signals during some abnormal trafiic condition. He can watch the trafiic movement and advance shaft 420 as fast as conditions warrant.

It is of course understood that the specific description of the structure set forth may be departed from without departing from the spirit of this invention as disclosed in this specification and as defined in the appended claims.

Having now described my invention, I claim:

1. In a traffic signal system for controlling Stop and Go signals for intersecting main and cross streets, the combination of a step switch for operating said signals in a predetermined sequence, a plurality of timers, each for operating said step switch according to a predetermined time schedule, selecting means for selecting one of said timers to operate said step switch and to stop the other timers, locking mean for preventing operation of said selecting means, and a release circuit operative when said timer reaches a predetermined position whereby said timer is stopped in said position and the other selected timer is started from said position.

. In a tr-afiic signal system for controlling Stop and Go signals for intersecting main and cross streets, the combination of a step switch for operating said signals in a predetermined sequence, a solenoid for advancing said step switch step by step, a plurality of cycle dials having adjustable actuators, driving means to rotate each dial, control :sv-J'itches-associated with each dial and operated by said actuators to energize said solenoid and advance said step switch according to a timed schedule, circuits for connecting said step switch to a selected one of said dial control switches including a synchronizing circuit for maintaining a synchronized relationship between said selected chal and said step switch whereby the Go signal is transferred from the cross street to the main street when said dial is in a predetermined position, a relay means having multiple positions, said relays means in one position energizing the driving means for one of said dials, deenergizing the driving means of the other dials, and connecting said circuits tov the control switches. associated with said dial, said relay .means. in a second position energizing the driving :zmeansfor a second. one of said .dials, deenergizing the drivingmeans for the first dial, and conmeeting said circuits to the control switches asso- -.ciated with said second dial, a selector switch iorgpositioning relay ,means, locking means preventing movement of said relay means, and

-release means effective when the dial actuating the step switch is in a predetermined position to render said locking means ineffective, whereby said first dial is stopped in said predetermined position and the other dial is started.

-". In a traffic signal system, a set of trafiic signals, a step switch for operating said signals in a predetermined sequence, a first motor driven dial, adjustable actuators rotated with said dial,

a first switch closed by said actuators for advancing said step switch step by step according to thespacing of the actuators on the dial, a second motor riven dial, adjustable actuators rotated with said second dial, a second switch closed p y-said actuators for advancing said step switch, .a transfer relay having one position for causing operation of said first motor driven dial and con-' ;necting said step switch to said first switch and having a second position for operating said second motor-driven dial and connecting said step switch tosaid second switch, a third switch for selecting the first and second positions of said relay, latch means for latching said transfer relay in its first or second positions, a release coil on said relay, a fourth switch comprising part of said step: switch and operable when said step switch is in a predetermined" position to energize said releasecoil, said release coil effective to release the latch means allowing the transfer relay to assume the position determined by the third switch and transfer the step switch control to the otheridial and to start its motor.

:Irra traffic signal system, a set of traffic signals, a step switch for operating said signalsin a predetermined sequence, a solenoid for advancing said step switch, a pluralityoi timers for energizing and deenergizing said solenoid to advance said step switch according to a cyclic timed schedule, a relay normally connecting said solenoid to one of said timers to be advanced thereby, a second switch to operate said relay .to disconnect said one oi timer from said solenoid and to connect another timer thereto,

locking means to prevent operation of said relay by second switch, and release means including a first means, a cam actuated by said step switch normally preventing operation of said first means except in a predetermined position of said step switch, and a second means actuated by said solenoid normally preventing operation of said release means when said solenoid is deenergized whereby said locking means is released when the contact on said step swltchsis in a predetermined positionqand said solenoid is energized.

' 5. In a trams control system for controlling a series-of top and Go ignals at cross streets intersecting .c-ain stre t, the combination oi a seriesof controllers, each controller having a step switch for-operating the signals at an intersection predetermined sequence, a plurality of cycle having adjustable actuators to advance said step switchaccording to a timed scheddie-driving means for each dial, relay means for connecting step switch to a selected one of dials to operate the driving means for selected dial, synchronizing means between step switch and the selected dial whereby the e in a predetermined position when the -;;o"szgnal is transfered to the main street, a

' seector switch for operating the relay means in the controllers 20' to select a dial to operate the said each, locking means in each cona release switch to release locking means a cam on said step switch for closing said release switch in one position of said step Stop Go signals at a traffic intersection, the combination of a cyclically opera ed switch for operating saic s'; a timed sequence, a relay connecting said signals for a secondary sigolay, a control switch for energizing said to select secondary signal display, a cyclically operated switch closed in predetermined position of the cyclically operated switch and connected in series with said control switch and relay to prevent operatthe relay except when the cyclically operated switch is in said predetermined position, and a :ontact on said relay to stop the cyclically operated switch when the relay is energized.

a trail;-

controller, Stop and Go a cyclically operated signal switch for op ting. said signals in a timed sequence, arelay a plurality of contacts having one position connecting said signals to said signal switch and a second position to connect said signals for a non-cyclic signal indication, a circuit to operate sai el including a first switch to select the pc ion of said relay, a second switch in series w h the switch, and. 1: cans on said signal switch to operate said second switch when the si-nal switch in a predetermined position, one or relay contacts connected to stop the advance of step switch in said predetermined position.

8. In a traffic signal system, the combination by step to energize said traflic signals in a predetermined sequence, a plurality of timers providing impulses to advance said step switch, selector switch means normally connecting one of said timers to advance said step switch and operable to disconnect said one of said timers and to connect a second timer to advanc said step switch, interlock means for preventing the operation of said selector switch, a control switch for releasing said interlock means, a cam on said shaft for closing said control switch in a predetermined position of said shaft, a second cam free to oscillate about said shaft and shaped to hold said control switch unresponsive to said first cam in one position, and responsive to said first cam in a second position, and connecting means between said second cam and the solenoid to hold the second cam in one position when the solenoid is deenergized and to move the second cam to the other position when the solenoid is energized.

9. In a signal controller to provide a sequence of signal combinations, a step switch, a plurality of cycle dials each including a control switch for advancing the step switch, actuators carried by each dial for operating the control switch and means for rotating each dial, a selector switch to select one of said dials to advance said step switch, operating means operated by a predetermined actuator closing its control switch, and transfer means operated by said operating means to connect the control switches associated with the dial selected by said selector switch to said step switch.

10. In a signal controller to provide a sequence of signal combinations, a step switch, a plurality of cycle dials each including actuators carried by each dial for advancing said step switch, a motor for rotating each dial, transfer means operable to connect said step switch to a selected dial and to start its motor and to stop the other motors and dials, a selector switch to select one of said dials to advance said step switch, operating means operated by a predetermined actuator closing its control switch, and transfer means operated by said operating means to connect the control switches associated with the dial selected by said selector switch to said step switch.

11. In a signal controller to provide a sequence of signal combinations, 2. step switch. a plurality oi cycle dials each including actuators carried by each dial for advancing said step switch and means to start and stop rotation of each dial, selector means operative to start rotation of a selected one dial, stop rotation of the other dials and connect said step switch to the selected dial to be advanced thereby, means for operating said selector means to stop one dial in a predetermined position and to start another of said dials from said position thereby maintaining a synchronized relationship between said selected dial and the step switch, said means including a first interlock switch actuated by said step switch in one position thereof, and a second interlock actuated by said one dial when said dial is in a predetermined position to advance said step switch.

12. In a tramp-signal system, the combination of a set of trafiic signals, a step switch operable step by step to energize said trafiic signals in a predetermined sequence, a plurality of timers pro viding impulses to advance said step switch, connecting means normally connecting one of said timers to advance said step switch and operable to disconnect said one of said timers and to connect a second timer to advance said step switch, and means for preventing the operation of said connecting means, a release means for said connecting means comprising a first means on said step switch to hold said release means inoperative except in a predetermined position of said step switch and a second means, actuated by an advancing impulse from the timer connected to advance said step switch, to render said re lease means responsive to the first means.

13. In a trafiic-signal system, the combination of a set of traffic signals, a step switch including a shaft operable step by step to energize said traffic signals in a predetermined sequence, a plurality of timers providing impulses to advance said step switch, connecting means normally connecting one of said timers to advance said step switch and operable to disconnect said one of said timers and to connect a second timer and to advance said step switch, a selector switch for se lecting one of said timers to operate said step switch, an actuating means operated by a timer impulse which advances the step switch to a predetermined position, and transfer means responsive to said selector switch and said actuating means to connect the selected timer to the step switch.

14. In a trafic signal controller, Stop and Go signals, a step switch having. a plurality of switches for operating said signals in a predetermined sequence, a timing motor, a pair of switches connected to said step switch to advance it, step by step, upon operating said switches, actuators driven by said timing motors to operate one of said pair of switches in a time schedule, said one of said pair of switches connected in series with a switch on said step switch which renders said one of said pair of switches inoperative in one position of said step switch, an actuator driven by said motor to operate the second of said pair of switches to advance said step switch out of said one position, thereby synchronizing the step switch with the actuator driven by the motor, a relay having a plurality of contacts to connect said signals to said step switch in one position and to connect said signals for a secondary signal indication in a second position, a circuit to operate said relay including a selector switch to select the position of said relay, a control switch in series with the selector switch, means on said step switch to operate said control switch when the step switch is in a predetermined position,

. and a contact on said relay held open in said second position of the relay, said contact in series with said second pair of switches to prevent the actuators from advancing the step switch from said one position of said step switch when said relay is in its second position.

FRANK ARTHUR PEARSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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