US2324051A

US2324051A - Traffic signal control apparatus

Info

Publication number: US2324051A
Application number: US445457A
Authority: US
Inventors: John J Alles
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-06-02
Filing date: 1942-06-02
Publication date: 1943-07-13
Anticipated expiration: 1960-07-13

Description

Jul 13, 1943. ALLES 2,324,051

TRAFFIC SIGNAL CONTROL APPARATUS Filed June 2, 1942 s Sheets-Sheet 1 July 13, 1943.

-J. J. ALLES TRAFFIC SIGNAL CONTROL APPARATUS Filed June 2, 1942 6 Sheets-Sheet 2 HTTORNEYS.

y 1943- J. J. ALLES 2,324,051

TRAFFIC SIGNAL CONTROL APPARATUS Filed June 2, 1942 6 Sheets-Sheet 3 i L 1 INVENT OR HTIORNEYS.

July 13, 1943. J. J. ALLES 2,324,051

TRAFFIC SIGNAL CONTROL APPARATUS Fil ed June 2, 1942 6 Sheets-Sheet 4 July 13, 1943.

J. J. ALLES TRAFFIC SIGNAL CONTROL APPARATUS Filed June 2, 1942 6 Sheets-Sheet 5 I N VEIYTOR. B 7

y 1 1943- J. J. ALLES 2,324,051

TRAFFIC SIGNAL CONTROL APPARATUS Filed Jpne 2, 1942 6 Sheets-Sheet 6 @ll IE? 0 I 8 b i -Fi g. 7

INVENTOR.

Patented July 13, 1943 UNITED STATES PATENT OFFICE 2,324,051 'rnsmc SIGNAL com'nor. msna'rns John J. Alice, Wilkes Barre, Pa. App ication June z, 1942, serial No. 445.457 14 Claims. (01. 171-337) This invention relates to control apparatus for, successively energizing a plurality of working circuits in a predetermined timed sequence.

The invention is herein illustrated and described in connection with a street trafllc signaling system wherein the green, amber and red signals are operated through repeated cycles.

When tra'fllc signals first went into commercial use, they were operated by relatively simple controls or timers in the nature of timers then in use for controlling signs. As the use of traffic signals grew, it became apparent that the si n flasher was not suitable; for use as a traiiic signal timer. It was particularly not adapted to provide the many adjustments and variations that traiiic signaling systems. Accordingly. over a period of some twenty years many special timers, both mechanically and vacuum tube operated, were designed. for tramc slsual use and such timers progressively became more complicated and expensive to manufacture, this being particularly true when it was attempted to emciently control traiiic at intersections other than the common two street intersection for example, three, iour, live and six street intersections. The proper movement of trailic at these multiple street intersections is rather complex and if suit- ,able adjustments are provided for in the timer the mechanism becomes complicated and such timers are usually especially built for a particular intersection, with the result that they are relatively expensive and are of no value except for use on such an intersection.

The chief object of my invention is a timer or control apparatus embodying a number of individual control units. For example, an individual control unit for each street at the intersection, and the apparatus beingso constructed and ar ranged that these control units may be added or taken away at will, whereby a timer initially installed to handle a two street intersection may,

' by simply adding another control unit, take care of a three street intersection.

The invention has as a further object a'control apparatus of the type referred to wherein the individual control units are all of like construction and the construction or these units being "extremely simple, with'the result that they can be manufactured at a low cost. are particularly durable and efficient in operation'and, inasmuch asthey are jack mounted, can-be instantly rewere eventually required in more complicatedof the electrical department. It is also important because it permits the cities to readily convert timers to obtain any number of traiilc movements desired at any particular location.

The invention has as a further object a construction whereby each individual control unit embodies means permitting the adjustment of certain periods of the trailic cycles on its street independently of the other periods. For example, if it is desired to lengthen the amber or caution period on one street, the adjustment is conveniently made without taking any time from either the red or the green period on that street.

Each of the control units operates through a cycle, at the end of which the unit comes to rest with one of the work circuits closed. Each unit is returned to its initial position and is again started upon its cycle by action of one of the other control units in the controller. In other words, the arrangement is such that the peration of each control unit is initiated by one of the other control units used in the controller.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

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

Ficure 1 is a schematic wiring diagram illustrating the arrangement and operation of the control apparatus which is illustrated with three control units for three traiilc lanes or streets, the units being positioned with the red signal dis.

played on streets A and B. and the amber signal on street 3.

Figure 2 is a view, similar to Figure 1, with the apparatus positioned showing the green signal displayed on street A, and the red signal on streets 3 and C.

Figureiiisaview similartoFigures 1 and2. illustrating the display of the amber on street A. andtheredonstreetsliandc.

Figure 4 is a front elevational view of a cam unit embodying my invention.

Figure 5 is a side elevational view of one of the control units with the motor and reduction gearing shown in section.

Figure 8 is a rear elevatlonal view of a control unit.

Figure 7 is an elevational view of the inner side of the face plate of a control unit.

Figure 8 is an elevational view of the control switches and operating mechanism.

Figure 9 is a fragmentary sectional view of the cam shaft and adjusting mechanism.

In the drawings. the controller is illustrated as having three individual cam units arranged to operate traiilc signals at an intersection having three traiilc lanes or streets. The arrangemerits and circuits of the control apparatus can be more easily understood by making reference first to the diagrams shown in Figures 1, 2 and 3. These cam units are designated A, B and C, it being understood that the signals associated with each cam unit control trafiic on streets or lanes A, B and C respectively. The green, amber and red signals, associated with unit A, are indicated at It, II and I2;'those associated with unit B I3, I4 and I5, respectively, and those associated with unit C I 6, I1 and 63, respectively. While in the diagrams a green, amber and red signal is shown for each traffic lamp, it will be further understood that in the conventional installation there will be a second set of signals facing traf fic moving in the opposite direction on each street. The green'and amber light for each street are controlled by a switch or switches actuated directly by th cam of the associated cam unit. The red signals on each of the streets are controlled by a relay controlled by the cam unit with which the red signal is associated, the energizing circuit of the relay being connected to the red signal circuit of one of the other wire 21. In like manner, the green and amber signals I3; I4 are connected to contacts 28, 29 respect vely through

wires

30, 3|, and the green and amber lights I6, 81 to

contacts

32, 33, through

wires

34, 35.

A movable contact 36 is arranged to be moved into and out of engagement with the contacts 24,

26, and isconnected to a stationary contact 40 through wire 4|.

The contacts 28, 29 are controlled by movable contact 42 connected to stationary contact 43 through wire 44, and the

contacts

32, 33 are energized by movable contact-45 connected to contact 46 through wire 41.

Contact 40 is energized by the armature or movable contact 50 connected to the hot side 5! of the supply through wire 52. The armature 50 is under the control of a relay coil 53. The contact 43 of unit B is energ zed by armature 54 connected to wire 5| through wire 55, the arma ture being under the control of relay coil 56,

15, i3 and 11 respectively. The gear housings are rotatably mounted upon the

shafts

88, 61, 68; 15, 16, 11. The

cam

62, 63 and 64 may be insulated from their

shafts

66, 61, 66, by being mounted upon disks 18 of insulating material.

A disk is secured to the shaft 66 and similar disks 8|, 82 are secured to the shafts 61, 88. The disks 80, BI, 82 are provided with radially extending

projections

88, 64 and 85 cooperable with

stops

86, 81 and 88 when the associated cams e2, 63 and 64 are in initial position, as indicatedin unit A, Figure 1.

A helical torsion spring 93 is secured at its inner end to-disk 80 as at 9|, and at its opposite end to a fixed pin 92. The arrangement is such that when the shaft 33 is rotated to move the cam -32 through its arc of rotation, the spring 90 is wound up. That is, the rotation of the shaft 83 is against the tension of the spring and accordingly, the spring 90 yieldingly urges the shaft 36 and the associated cam 62 back to its initial position. Similarly, a spring 93 is associated with disk 8| and a spring 96 with disk 82.

Referring to Figure 1 of the drawings, the cam 32 and disk 80 in unit A are in their initial or starting position with movable contact 36 in engagement with contact 24. However, the green s gnal I 0 is not illuminated due to the fact that relay 53 is deenergized and its armature 50 is out of engagement with contact 49 and is dropped into engagement with stationary contact I00 which is connected to the red lamp I2 through wire IOI. Accordingly, the red-light is energized on streetA.

Cam 63 and disk 8| of unit B have traveled through their are of movement and have come to rest with the highest part of the lobe I03 of the cam in engagement with the movable con- 56 is also deenergized thus breaking the feed circuit to contact 43. The red light I5 is however energized through wire 55, armature 54, contact I05 and wire I06.

Cam B4 and disk 82 in unit C have traveled through a portion of their are of movement and and the contact 46 of unit C is energized by armature 58 connected to wire 5| through wire' 59, this armature being controlled by relay 60.

It will be observed that each of the cam units A, B and C consist of identical part in identical arrangement. However, separate numbers have been assigned to the respective part 01' each unit in order that the cyclic operation hereinafter set forth may be more readily understood.

The

contacts

36, 42, 45 are actuated into and out of engagement with their associated stationary contacts by

cams

62, 63,64. These cams are mounted upon and rotate with

shafts

66, 61 and 68 respectively, these shafts being rotated by'

motor

69, 10; 1| through reduction gearing arranged in the

respective gear housings

12, 13, 14. The

motors

69, 10, 1| are connected to the gearing in

housings

12, 13 and 14 through their shafts III) are so positioned that the low part of the cam lobe I01 is in engagement with the contact 45 and has moved the same into engagement with con tact, 33. Inasmuch as the relay in unit C is now energized, a hot feed is provided to the amber light through wire 59, armature 58, contact 46,

wire 41,

contacts

45, 33, and wire 35.

Relay 50 in unit 0 is energized throughwire I08 connected to wire I06 energizing the red si nal I5 in unit B through a movable contact I09, stationary contact IIO, wire III, relay 60, wire H2, to the common side 20. Wire III is also connected to coil II3 of motor 1| through wire- II4, theopposlte side of the coil being connected to wire 2 to the common return 20. Accord ingly. the motor H is energized and is operated effecting rotation of cam 64 and disk 82.

From the above description, in connection with Figure 1 of the drawings, it is apparent that

motors

69, 10 of units A and B are deenergized and the red lights I2, I5 are displayed. Motor H of unitC is energized, cam lobe I01 having just shifted the movable contact 45 from contact 32 to contact 33 effecting a shift from the green sig-- 2,324,051 I22 and I28 normally engaging the projections I28 and being withdrawn from engagement therewith by the respective solenoid coils I28, I28

and I 21. One side of the coil I21 is connected to the wire I I2. Similarly, the coil I 28 is connected to the wire I28 and the coil I28 to wire I28. The opposite side of coil I28 is connected through wire I80 to the feed wire 88 for the amber lamp I1 on street C. The other side of the coil I28 is connected through wire I8I to-the feed wire 21 of the amber lamp II for street A, and the opposite side of coil I21 is connected through wire I88 to the feed wire 8i for amber lamp I8 on street B.

Accordingly, inasmuch as amber lamp I1 on street C is illustrated as energized in Figure 1 of the drawings, the coil I28 is likewise energized moving the detent I2I out of engagement with the projections I on gear housing 12. The reduction gearing in the housings 12, 18, 18 is of the planetary type and functions when the housings are held against rotation to eficct rotation of the cam shafts by the respective motors. The arrangement of the motor shafts, cam shafts, housings and gearing within the housings, is illustrated more specifically in Figure 5. Due to the relatively great reduction in the gearing arranged in each of the housings 12, 18, 18, the housings are in practical effect, insofar as retrograde movement is concerned, coupled to the

respective shafts

88, 81, 88. Accordingly, when the

shafts

88, 81, 88 have been rotated through their cycle or are of movement by their respective motors against the tension of the springs 80. 88, 88, and thereupon the detents I 2i H2 and I 28 are withdrawn from the projections I20, the housing; 12, 13, 18 and their associated

shafts

88, 81. G8 are rotated in retrograde movement until the

projections

88, 88, 88 of the

respective disks

80, 8i, 82 engage their respective stops 88, .81, 88. Accordingly, when the amber lamp I! on street C was illuminated, cam unit A was returned to its initial position as indicated in the drawings. And likewise, because of the relatively great reduction in the gearing arranged in the respective hous- V ings, the

shafts

88, 81, 88 are prevented from returning to their initial position until the housings have been released by their detents.

In Figure 2 or the drawings. cam 88 has advanced to the end of its movement with the highest portion of the lobe I01 in engagement with causing the insulating member I88 to engage adlusting screw I80, moving contact I08 out of engagement with contact IIO, thereby breaking the feed circuit to relay 80 and motor coil II8. Accordingly, cam unit C stops in this position, retro- ZII of engagement with their respective stationary contacts, the associated amber light is extinguished. Accordingly. the time within which the movable contacts are actuated determines the duration of the amber and accordingly the duration of the amber is adjustable by adjusting the screws I80.

As previousLv explained, when the amber lamp I1 on street C was energized, solenoid coil I28 of unit A was also energized retracting the detent I2I from engagement with the housing 12, thus permitting cam 82 to return to its initial position as shown in Figure 1. Subsequently, when the red light I8 of unit 0 was energized, relay 88 of unit A was energized through wire I80 connecting wire I88 to contact I88 which, at this time, is in engagement with contact I81, the latter being connected by wire I82 to the motor coil I88 of motor 88 and by branch wire I88 to the solenoid 88, the wire I28 serving a a return circuit for relay 88, mil I28 andmotor coil I88.

Referring now again to Figure 2, the motor 88 of unit A has rotated cam 82 so that the lobe I85 is about ready to engage contact 88 to move the same out of engagement with contact 28 connected to the green light I0 and move it into engagement with contact 28 connected to the amber lamp it. when this happens, as illustrated in Figure 3, the coil I28 of unit B will be energized moving the detent I22 out of engagement with housing 18 permitting cam 88 to be returned to its initial position by action of spring 88.

It will be observed that in Figure 1 the red light was displayed on streets A and B, and the amber light was displayed on street C. In Figure 2, because oi the display of the amber light on street C in Figure 1, unit A was returned to its initial position and when unit (2 advanced far enough to deenergize the relay 80 and energize the red signal i8, the red signal on street A was extinguished and the green signal illuminated because of the shifting of the contact 80 upon the energization of relay 88, and when unit A had advanced to the position shown in Figure 3. the green light on street A was extinguished and the amber light I I illuminated and simultaneously unit 0 returned to its initial position. Now when the unit A advances to its final position and moves contact I88 out of engagement with contact I8l, relay 88 will be deenergized permitting contact 80 to move out of engagement with contact 80 thus extinguishing the amber lamp II and moving into engagement with contact I00 to energize the red signal I2 through grade movement by spring 88 being prevented because of the fact that detent I 28 is in engagement with the projections in on gear housing 14.

Deenergization of relay 88 has effected display of the red signal I8 on street C through movable contact 88, stationary contact I82, wire I88. Units A and B are provided with movable contacts I88, I88 respectively, which contacts are comparable to contact I08 of unit C. Each of wire IM andthereupon through wire I81, contacts I88, I88, wire I89. The motor coil I of motor 10 will be energized to actuate cam 88 on its cycle and simultaneously the relay 88 will be energized through branch wire I8I, in this instance the wire I28 serving as a common return for both relay 88 and motor coil I80.

This operation effects movement ofcontact 88 out of engagement with contact I 05 and into engagement with contact 88. This completes a circuit from the hot side of the line 8i tothe green light I8 on street B through wire 88, movable contact 82, contact 28, wire 80, green light I8 and thence to the common side 20 through wire 22.

Unit B continues to operate through its cycle shifting contact 82 out of engagement with contact 28 and into engagement with contact 29, thus extinguishing the green light I 8 and energizing the amber light I8 and simultaneously energizing coil I21 of unit C, causing the detent I29 to move out of engagement with the housin is and permitting cam 09 to return to its initial position and at the end of its travel, as illustrated in Figure 1, cam 03 has moved contact I95 out of engagement with contact IEB-breaking the circuit to relay 59 and effecting display of the red signal I5 as previously described.

It will be apparent that these individual control units are operable through a cycle to successively display the green, amber and red signals on their respective streets, and are also operable to shift or return one of the other units to its initial position, and upon display of the red light to initiate another one of said units on its cycle, whereby all of these units are electrically interconnected and can notget out of step with each other.

' The stop pins 96, Bl and 88 are adjustable circumferentially of the disks 80, BI and 02 in both directions, as indicated by arrows I on the.-

schematic diagrams Figures 1, 2 and 3. This results' in'changing the initial position of the respective cams. When any of the pins are moved in a clockwise direction, the lobe on the associated cam must travel a greater distance before engaging the contacts 99, 92, I5, and thus a greater time interval is provided for the green light.

The arrangement of the contacts for the green and amber signals such as 25, in unit A, the

movable contact as 39, and the associated cams 02, 93. 94, is such that the amber contacts 20, 29. 39, are engaged by the

contacts

36, 92, 95, immediately upon disengagement with the green con- 1 pole, double throw switch and serves to control the green and amber signals associated with each unit. The switch I89 is of the single pole, single throw type and serves to control the relay I817. The switch I85 is provided with an actuating stem I89. and the switch I80 with an actuating stem I89. The contacts of these switches are actuated by a slight axial movement of the stems I98, I99, the switch I85'being comparable to

contacts

25, 20, 390i un t A: contacts 29. 29, 32 of unit B, and

contacts

33, 32, of unit C, as illustrated in the diagrams Figures 1, 2 and 3. Similarly the switch I serves the function of contacts I90, IEI, I95, I58, and I09, N0 of units A, B and C, respectively, as shown in the diagrams. The specific structure of these switches is illustrated in Patent No. 1,960,020. The switch I is fixedly secured to the plate I 80, and the switch I80 is pivotally mounted as at I90. The

' stem of switch I85 is operated by lever I9I pivoted at I92 to a bracket I93 secured to the switch I85. The lower end of the lever I9I is provided with a roller I99 engaged by a cam I 95 secured to a cam shaft I journalled in the plate I00 and extending into the gear housing I99.

The lever I9I is provided with an upwardly eX- tending finger 200 which is movable into andout of engagement with stem I89 of switch I90 to 'efiect actuation thereof. The cam I has associated with it a disk 20I provided with a radially extending pin 202 and with an axially extending pin 203. The outer end of the cam shaft I96 terminates at the disk 2IlI. Astub shaft 205 is journalled in the face plate I8I and provided at its outer end with an adjusting knob 205 and having secured to its inner end a disk 20? having an annular flange 208 facing the disk 20L The disk 20? is provided with a pin 209 arranged within and adjacent to the flange 208. A torsion spring 2I0 is arranged Within the flange 209 having its outer end secured to the pin 209 and its inner end secured to the pin 203 on disk 20L The disk 201 is also provided with a pin 2II arranged to be engaged by the radially extendin p-n 202. The disk 201 is rotatably adjustable by the knob 206 and is frictionally retained in adjusted position by a washer spring 2I2 interposed between the disk and the inner side of the face plate IOI.

The inner end of the cam shaft I98 is provided with a gear 2I5 arranged to mesh with the re-' duction gearing arranged in the housing I99 and which is driven by the motor shaft 2I5 on which the rotor H1 is mounted also within the housing I99. The housing I99 is rotatably journalled upon the cam shaft I96 and is provided at its rear end with a stub shaft 220 journalled in a supporting bracket 2.2I secured at its ends to the field poles 223 of the motor as by studs 22% which, in turn, are secured at their opposite ends to the supporting plate I80.

In regard to the structure just smcifically described, the motor shaft 2I6 corresponds to the shafts I5, I6, 7.1 in Figures 1 to 3, and the shaft, I95 corresponds to the

respective cam shafts

95, 57, 68, and the housing I99 corresponds to the respective housings 72, I3, M. The housing I99 is formed at its periphery with a plurality of teeth 225 corresponding to the projections I 20 in the diagram, and these teeth are engaged by a detent 226 carried on armature 227 of a relay 228, the armature and relay corresponding to the detents and solenoids I2I, I25; I22, I26; I23, I27 in the diagrams. The detent 220 is yieldingly urged into engagement with the ratchet teeth 225 by spring 230.

With this arrangement the cam is located in its initial position by the pin 202 contacting the stop pin 2 carried on disk '20]. When the motor 223 is energized, the cam shaft I96 is rotated by means of the reduction gearing in housing I99 whereupon the cam engages roller I90 causing actuation of stem I88 of switch I 85 to shift the green signal associated with this unit to amber. Upon further rotation of the cam I95 by the motor, the tail piece 200 actuates stem I89 of switch I86 breaking the circuit to relay I87 and to the motor 223 whereupon rotation of cam I95 and shaft I98 ceases and the circuit to the red light under the control of this unit is completed through the contacts of relay I81 and at the same time the circuit to the associated amber signal is opened. The relay I81 corre- "sponds to the

relays

53, 56 and 60 in the diagrams.

During the rotation of the cam I95 and disk 20I associated therewith, the torsion spring 2! has been wound up and When relay 228. is energized by a succeeding cam unit causing detent 226 to move out of engagement with teeth 225, the housing I99 and the cam shaft I 95 are rotated retrograde until the pin 202 engages the stop 2I I whereupon the unit is again positioned to commence another cycle" when the motor 229 becgmes energized by the next preceding cam uni It will be observed that the duration of the green signal is adjusted by rotating .the knob 206 effecting rotation of disk 20'! and accordingly the stop pin 2 carried thereby, thus adjustin the initial position of the cam shaft in the same manner as explained in regard to the schematic diagrams.

As previously explained, the switch I86 is pivotally mounted at I90 to the supporting plate I80. This switch is connected to a pin 230 eccentrically mounted on the stud shaft 23I journalled in the face plate I8I and provided at its outer end with an adjusting knob 232. The connection to the pin 230 is by means of a link 234 pivotally connected at one end to the switch I86 and at its opposite end to the eccentric pin 230. The pivotal mounting of switch I86 and/or the connections with link 234 are such that the switch is frictionally held in adjusted position. It will be apparent that upon rotation of the adjusting knob '282, the actuating stem I89 of the switch I86 is moved toward and from the operating tail piece 208, whereupon the time interval of the actuation of this switch after the actuation of the contacts of switch I85 may be varied and results in controlling the duration of the amber signal. It will also be apparent that any adjustment of the disk 2! eifecting adjustment of the duration of the green signal is entirely independent of any adjustment of switch I86 controlling the duration of the amber period and vice-versa, the adjustment ofthe one not adding to nor subtracting from the period of the a other.

I call further attention to the compact and emcient arrangement of the cam units which may obviously be still further reduced in size and cost by employing switching mechanism other than that illustrated in Figures 4 to 9, by way of switches I85, IBG. These units are not ,only compact and economical to build, but are particularly well adapted to be jack mounted upon the wall of a control cabinet or other suitable support. To this end, a plate 240 is secured to the upper end of the support plate I80 and on which are mounted a plurality of prongs 24I extending rearwardly, these prongs being adapted to be positioned in receptacles 242 arranged upon a suitable support 243. All connections extending from one cam unit to another are connected to the prongs 2 as, for example referring to unit A, Figure 1, the line conductors 20, 5|.

signal circuit conductors

25, 21, I88, and conductors I30, I3I, I50, extending to the solenoid of the detent I2I from the amber signal circuit and from the red signal circuit respectively. Accordingly, in the event any cam unit should become out of order, it is only necessary in removing that unit to pull it out of theiack mounting 242, whereupon a replacement unit can be immediately mounted in place thereof. This is an important feature in that it avoids the necessity of the person in charge of thetraflic signaling system in making repairs or substantial adjustments at the intersection, and permits him to take the defective unit back to the repair shop where it can be more conveniently and quickly repaired.

While I have illustrated the detent operating coils I22, I28, I25, as being connected in parallel with the amber signal circuit of the "preceding unit, it will be apparent that these detent coils may be connected in parallel with the green signal circuit of the preceding cam unit. In either event, the unit is returned to its initial position prior to the time it commences its active cycle.

What I claim is:

1. A traffic signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for each street, each control unit including timer operated 'means operable when energized to move from initial position through a cycle to successively display the green, amber and red signals on its street, means cooperable, upon the display of one of said signals, to return another one of said units to its initial position, and means operable, upon the display of the red signal to energize the timer operated means of said other control unit.

2. A traffic signal control apparatus for controlling the' green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for each street, each control unit including timer operated means operable when energized to move from initial position through a cycle to successively display the green, amber and red signals on its street, means cooperable, upon the display of one of said signals, to return another one of said units to its initial position, and means operable, upon the display of the red signal to energize said other control unit, and means operable to adjust the duration of the display of the green signal by each unit independently of the dura tion of the display of the amber or red signal.

3. A traffic signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for each street, each control unit including timer operated means operable when energized to move from initial position through a cycle to successively display the green, amber and red signals on its street, means cooperable, upon the display of the amber signal, to return another one of said units to its initial position, and means operable, upon the display of the red signal to ener- "gize said other control unit, and means operable to adjust the duration of the amber signal independently of the duration of the green or red signal.

4. A traiiic signal control'apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for the signals on each street, each unit including a plurality of switches for controlling the signal circuits, a cam shaft, cam means mounted on the shaft for actuating said switches, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing, gearing arranged in said housing, said gearing being operable by the motor while said housing is restrained against rotation to eifect rotation of said cam shaft from initial position to actuate said switches through a cycle to successively display the red, amber and green signals to the street under the control of said unit, a, detent movable into and out of engagement with said housing and being operable when in engagement with the housing to hold the same against rotation, means yieldingly opposing rotation of said cam shaft by the motor and being operable to effect retrograde movement of said shaft to return the cam means to initial position when said detent is moved out of engagement with said housing, electro-responsive means operable when energized to move said detent out' of engagement with the housing, and said means being energized concurrently with the display of one of the sig-,

the signals on each street, each unit including 4 a plurality of switches for controlling the signal circuits, a cam shaft, cam means mounted on the shaft for actuating said switches, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing, gearing arranged in said housing, said gearing being operable by the motor while said housing is restrained against rotation to effect rotation of said cam shaft from initial position to actuate said switches through a cycle to successively display the red, amber and green signals to the street under the control of said unit, a detent movable into and out of engagement with said housing and being operable when in engagement with the housing to hold the same against rotation, means operable to effect return of the cam means to initial position when said detent is moved out of engagement with said housing, electro-responsive means operable when energized to move said detent out of engagement with 2,32%,Qbll

a cam shaft, cam means mounted on the cam shaft, a motor, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing and being operable while said housing is restrained against rotation to efiect rotation of said cam shaft by the motor to move the cam means from initial position through a cycle, detent means movable into and out of engagement with said housing and being the housing, and said means being energized coni currently with the display of the amber signal under the control of one of said other control units, and switching means operable upon the display of the redsignal by said other control unit to energize said motor.

6. A traiiic signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for the signals on each street, each unit including a cam shaft, cam means mounted on the cam shaft, a motor, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing and being operable while said housing is restrained against rotation to effect rotation of said cam shaft by the motor to movethe cam means from initial position through a cycle, detent means movable into and out of engagement with said housing and being operable when in engagement with the housing to hold the same against rotation, and means yieldingly opposing rotation of said cam shaft and being operable to effect retrograde movement of said shaft to return the cam means to its initial position when said detent is moved out of engagement with the housing, a pair of contacts connected to the green and amber signal circuits, a movable contact, said movable contact being positioned in engagement with the green signal circuit contact when said cam is in its initial position, and being movable bysaid cam means upon rotation thereof into engageoperable when in engagement with the housing to hold the same against rotation, means operable to effect return of the cam means to initial position when said detent is moved out of engagement with said housing, a pair of contacts connected to the green and amber signal circuits, a movable contact, said movable contact being positioned in engagement with the green signal circuit contact when said cam is in its initial position, and being movable by said cam means upon rotation thereof into engagement with the amber signal circuit contact, a relay operable when energized to furnish power to said first movable contact and when deenergized to furnish power to the red signal, a circuit for energizing said relay and said motor and including said second movable contact, said second movable con tact being, connected to the red signal circuit of one of the other control units, and electro-responsive means operable to move said detent out of engagement with the housing and being connected in the amber signal circuit of said other control unit. v

8. A tramc signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for the signals on each street, each unit including a plurality of switches for controlling the signal circuits, a cam shaft, cam means mounted on the shaft for actuating said switches, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing, gearing arranged in said housing, said gearing being operable by the motor while said housing is restrained against rotation to effect rotation of said cam shaft from initial position to actuate said switches through a cycle \to successively display the red, amber and green signals to the street under the control of said unit, a detent movable into and out of engagement with said housing and being operable when inengagement with the housing to hold the same against rotation, meansyieldingly opposing rotation of said cam shaft by the motor and being operable to effect retrograde movement of said shaft to return the cam means sponsive means operable when energized to move said detent out of engagement with the housing,

and said means being energized concurrently with thedisplay of the amber signal under the control of one of said other control units, and switching means operable upon the display of the red signal by said other control unit to energize said motor, and means for adjusting the initial position of said cam means.

9. A tramc signal control apparatus for con asaa osi trolling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for the signals on each street, each unit including a cam shaft, cam means mounted on the cam shaft, a motor, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing and being operable while said housing is restrained against rotation to -efiect rotation of said cam shaft by the motor circuits, a movable contact, said movable contact being positioned in engagement with the green signal circuit contact when said cam is in its initial position, and being movable by said cam means upon rotation thereof into engagement with the amber signal circuit contact, a relay operable when energized to furnish power to said first movable contact and when deenergized to furnish power to the red signal, a circuit for energizing said relay and said motor and including said second movable contact, said second movable contact being connected to the red signal circuit of one of the other control units, and electro-responsivemeans operable to move said detent out of engagement with the housing and being connected in the amber signal circuit of said other control unit, and means for adjusting the initial position of said cam means. I

10. A trafiic signal control apparatus for con-' trolling the green, amber and red signals on each street, of an intersection having two or more streets comprising an individual control unit for the signals on each street, each unit including a plurality of switches for controlling the signal circuits, a cam shaft, cam means mounted on the shaft for actuating said switches, motion transmitting means connecting said motor and cam shaft including a freely rotatable housing,

gearing arranged in said housing, said gearing being operable by the motor while said housing is restrained against rotation to effect rotation of said can shaft from initial position to actuate said switches through a cycle to successively display the red, amber and green signals to the street under'theqcontrol of said unit, a detent movable into and out of engagement with said housing and. being operable when in engagement with thehousing to hold the same against rotation, means yieldingly opposing rotation of said cam shaft by. the motor and being operable to 'eflect retrograde movement ofsaid shaft to return the cam means to initial position when said detent is moved out of engagement with said housing, electro-responsive means operable when energized to move said detent out of engagement with the housing, and said means being energized concurrently with the display of the amber signal under the control of one of said other control units, and switching means operable upon the display of the red signal by said other control unit'to energize said motor, and

means for adjusting the actuation of the amber signal circuit switch independently of the actuation of'the green signal circuit switch.

11. A trafiic signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets-comprising an individual control unit for each street, each control unit including timer operated means operable when energized to move from initial position through a cycle to successively display the green,.amber and red signals on its street, means cooperable, upon the display of the amber signal, to return another one of said units to its initial position, and means operable, upon the display of the red signal to energize said other control unit, and means operable to adjust the duration of the display of the green signal independently of the display of the amber or red signal of said unit and independently of the amber and greensignals'of each of the other units.

12. A trams signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for each street, each control unit including timer operated means operable when energized to move from initial position through a cycle to successively display the green, amber and red signals on its street, means cooperable, upon the display of the amber signal, to return another one of said units to its initial position, and means operable, upon the display of the red signal to energlze said other control unit, and means operable to adjust the duration of the amber signal independently of the duration of the green or red signal of said unit arid independently of the green and amber signals of each of the other 13. A traflic signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for each street, each control unit including timer operated means operable when energized to move from initial position through a cycle to succes sively display the green, amber and red signals on its street, means cooperable, upon the display of the amber signal, to return another one of said units to its initial position, and means operable, upon the display of the red signal to energize said other control unit, and means operable to increase the duration of the green and amber signals independently and without shortening the duration of any signal of any of said units.

14. A trailic signal control apparatus for controlling the green, amber and red signals on each street of an intersection having two or more streets comprising an individual control unit for each street, each control unit including timer operated means operable when energized to move from initial position through a cycle to successively display the green, amber and red signals on its street, means cooperable, upon the display .of theamber signal, to return another one of said imits to its initial position, and means operable, upon the display of the red signal to energize said other control unit, and means operable to decrease the duration of the green and amber signals independentlyand without increasing the JOHN J. ALLES.