US2236299A - Traffic signal controller - Google Patents

Description

March 25, 1941. R. A. REID TRAFFIC SIGNAL CONTROLLER Original Filed April 25, 1958 3 Sh9ets sheet 1 Figi.

Iverwtor: Ralph A. Feiol,

` His Attorney.

March 25 19414, R. A. REID TRAFFIG SIGNAL, CONTROLLER original Filed April 23, 1958 3 Sheen-Sheet 2 fm, m

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muy VJ n March 25, QL R A, REID TRAFFIC SIGNAL. CONTROLLER Original Filed April 25, 1938 3 Sheets-Sheet 3 Inventor. Paph A.F?e icl M/J f y His Attorney.

Patented Mar. 25, wel.

UNITED STATES PATENT oFFlcE TRAFFIC SIGNAL CONTROLLER Ralph A. Reid, Nahant, Mass., assigner to General Electric Company, a corporation of New York 21 Claims.

My invention relates to signal controllers, and more particularly to trailic signal controllers. This application is a division of my application S. N. 203,888, led lpril 23, 1938, which ls a Fi continuation in part of my application S. N.

105,684, led October l5, 1936.

One object of my invention is to provide an improved traino signal controller which is simple in construction, reliable in operation, and capable of performing respectively the several functions required or" apparatus' of this type.

Another object of my invention is to provide an improved indicating means for the cycle length setting of the traffic signal timer.

Another object of my invention is to simplify the structure oi the controller to increase its reliability and thereby decrease the cost of maintenance.

For a betterunderstanding oi my invention, together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

The term timer is herein used to designate the timing mechanism and the contacts for controlling the timing and sequence of energlzation of a group of traffic signals. It includes the driving motor and the mechanism necessary to accomplish an accurately timed and adjustable control of the circuits to the signals. The term controller is used to designate the complete apparatus for controlling a group of signals for an intersection, including a casing in which is mounted the timer, the switchboard, the manual control switch and any other auxiliary device that may be required to accomplish the necessary control of the tramo signals.

In the accompanying drawings, Fig. l is a front perspective view of my improved trame signal controller; Fig. 2 is a perspective view of a key used in the setting o the timer; Fig. Bis a perspective rear view of the timer; Fig. i is an .exploded view of the bottom oi the timer and the terminal board normally attached thereto; Figs. 5, 6, 7, 8, 9, l0, and il. are fragmentary views of elements of the timing mechanism; Fig. 12 is a diagram of connection of a controller and a group of intersection signals; and Fig. 13 is a sectional view looking in the direction of arrows Iti3 in Fig. l. A

Referring to the drawings in detail, Fig. l illustrates a iront perspective of an intersection controller comprising a casing E, a timer supported on hinges l and 8, and a terminal and Cil switchboard 9 mounted on the rear wall of the casing 5 below the timer t. A flexible cable it! connects the timer 5 to terminals on the switchboard 9 and a cable ll connects the switchboard terminals to the intersection signals. A handoperated switch I2 with a suitable length cable i3 is connected to the switchboard terminals lll. It is used to manually operate the trafc signals, and when not in use is stored in the bottom of the casing 5. The switchboard has mounted thereon line fuses l5 and a fuse i6' connected into the system synchronizing conductor, terminals l'l for the conductors in cable Il, anda hand-operated switch I8 used for changing the controller from normal sequence operation to hashing amber signal operation.

In Fig. 1, only the control panel 6 of the timer o is illustrated indetail. It is provided with a circular opening .I9 in which a dial 20 rotates. On the lower side of `this opening, a notch 2l having an arcuate length of about 60 is provided in which a pointer 22 is positioned to indicate the length of time required for a complete revolution of the dial 20, or in other words, the length of a complete time cycle. In the specific timer illustrated, the indicia markings under the pointer indicate that a range of time cycle length is provided which is adjustable between 40 and 180 seconds.

The dial 20 is provided with radial slots 23 arranged in a circle about the center of the dial in which keys 24 and |43 as shown in Fig. 2, are placed. The relative position of these keys to each other determines the relative lengths of the individual signal periods. A second group of radial slots 25 (see Fig. 3) arranged in a ,smaller circle about-the center of the dial 28 is provided to receive a key 28 which is similar to key 24, but is longer. cThe placing of this key in one of the slots 25 determines the relationship of the signal time cycle to other cycles in the system.

Fig. 2 illustrates in perspective a key 2li. It is an elongated sheet metal member having a body of such cross-section that it may be easily moved through a slot 23 and of such length as to engage and operate contacts mounted in back of the dial. It is provided with a head 2l which is notched to form a shoulder 2l and a handle 30. The key 26 is the same as key 24, except that its body is longer. The key M3 is similar to key 2Q, except that itlis longer and is provided with a notch H3 (Fig. l2). In operation, the keys are placed in their, respective slots until each head 2l engages the surface of the dial and prey vents any further movement inwardly.' A disc- 28 provided with an opening 29 is then mounted on the dial by means of .a thumb screw Si. This disc is of such diameter that it engages the shoulders 2l of the keys 24, and the opening 2l is so placed that its edge engages. the shoulder 21' on the key 26. Disc 28 thus serves to hold the keys in position. 'I'he handle ends of the keys 24 project over the edge of the disc 28 and thereby indicate their respective positions. The handle 30 ofthe key 26 projects through the opening 2J 'and indicates its position relatively to the keys 2d.

The panel of the timer e is further provided 15 with three control switches mounted in a horizontal row below the timer dial. Switch 32 controls the signal circuits. Switch 33 controls the automatic and hand operation of the signals and switch 34 controls the timer motor circuit.

2G The panel 6' is further provided ait its upper iight-hand corner with a lug 35 in which a screw 36 is mounted which engages a threaded opening in a lug 3l on the casing 5. By means of this lug and screw arrangement, the timer may be se- 35 cured in the casing, and if desired, may be unlocked and swung outwardly about its hinges 7 and 8.

The mechanism of the timer is illustrated in Fig. 3. This gure is a perspective rear view of o the timer having a cover 38, shown in Figa 1 and 4, removed to expose the mechanism. This mechanism consists essentially of a driving motor 'connected to drive the dial 20, a contact block which supports contacts actuated by the keys in the dial 2li, and of a drum controller with its operating mechanism arranged to yoperate the drum controller step by step in response to actuations of the contacts by the keys in the dial. The driving motor indicated generally by the o numeral 40 is prefer-ably a self-starting synchronous motor of the type disclosed in U. S. Patent 1,430,867 issued to H. E. Warren. It comprises a tubular casing 42 attached to a larger casing 42'. The tubular casing encloses an arma- 5 ture shaft which is connected to speed reducing l gears in the casing 42'. The speed reducing gears drive the shaflt 43 (see Fig. 12) which lis referred toas the motorishaft. A field 44 mounted on the casing 42 eiects a rotation of the armature and 50 motor shaft, /when it is energized. The motori` -is a modification of the motor described in the above Warren patent in that the casing 42 is lengthexed and two armatures are provided on the shaft/therein. One of the armatures cooper- 55 ates--with the field 44 and the second armature cooperates with 'a field 4s. The two neids u and 45-are mounted on the casing 42 in operative relation to the two armatur, respectively, to ef fect a rotation of said armature sham'. in opposite 6o directions. The elds are of equal strength, so that if. they are simultaneously energized, the armature and motor shafts are stopped. Only one neld, neld 4'5, is therefore norm-ally energized' and the second neld, e1d.44, is energized only 65 when irt is desired to stop the motor instantly.

This self-starting synchronous motorr.A which i may be stopped instantly provides a precise control of the timer, from a remote point since the motor will not coast after the 'braking current 70 is applied. The above-described motor stops and starts instantly and no inaccuracy results when the timer resynchronlzes with the master timer. As stated in the description of Fig. 1, the dial 2o rotates in the opening lay of the panel. m u order to' support the dial it is mounted on a shaft i (see Fig. 12) which projects. through a bearing in a. yoke 5B. The yoke 50 is attached to the back of .the panel 6' near the nim of the opening I! and extends across the opening. The front surface of the dial is substantially parallel -5 to and spaced slightly inwardly from Ithe surface of .the panel and the surface of the yoke is sufficiently spaced from the back surface of the dial to permit the keys extending from the back surface oi.' the dial to move freely with the dial. l0 A gear 52 is attached to the end of the shaft 5i projecting through the yoke. This gear is removable and may be replaced by other gears 52', 53, and 5t. These latter gears are stored, for convenience, on a pin on shelf et which pro- 1 5 jects from the lower edge of the panel The gear 52 on the dial shaft is driven by a pinion 5l on the end ofv the motor shaft d3. In order to support the motor d@ to maintain al i driving relation between the pinion 5l and the 20 gear 52, or one of the other available gears, the motor is mounted on a plate et. This plate is pivoted ait one corner on a screw 4l which is screwed into a lug 48 projecting from the yoke 5u. The cycle length indicating pointer 22 is ait- 25 tached to another corner of the plate and moves with the plate 4B when the latter is moved about its pivot to place .the motor pinion 5l into engagement with one of the gears placed on the dial shaft. Since each gear corresponding to a 30 desired cycle length is of a definite diameter, the position of therplaite about its pivot, and therefore the position of the pointer, will be in a specined position for each cycle length.

In order to lock .this plate in the desired .posi- 35 tion, a lug 5S (see Fig. 4) projecting from the inner surface of the panel is provided. This lug projects to the under surface of and partly under theplate. It is provided wit-h ascrew 58 at its end. A washer Sli is placed under the head of this 40 screw and projects over .the edge of the plate 46. When the screw 58 is tightened, it pinches the edge of this plate 46 'between the end surface of the lug and the surface of the washer thereby preventing any movement of the plate about its 45 current which is supplied thereto. This frequency being maintained constant, the dial speed is de- 50 termined by the gear ratio between the motor and dial shailts. The time required by the dial to make one complete revolution determines the length of a. cycle of operation, and the physical'J spacing of the keys in the dial slots determines the .time intervals into which a cycle is divided. This possibility of changing the dial speed to. gether with the large number of possible changes in spacing between keys provides a flexibility which adapts the timer for use at substantially all traiic intersections.

In order .to convert the above-rnentloned dial speeds and key spaclngs into correspondingly timed trafllc signal operations, contacts are provided on the back of the panel 'and'piaced in 65 the path of movement of the keys, so that the keys will actuate the contacts and close circuits which set into motion the operating mechanism of the drum controller at the desired time intervals to change the tramo signal circuits. The contacts which areto be operated 'by the dial keys are mounted in thel contact block 4i mounted above the dial on the back surface of the panel.

In Fig. 5 the contact block 4I is illustrated in cross-section to expose one of three pairs of contacts mounted therein. The three pairs of contacts are mounted side by side, the pair nearest the surface' of the panel being arranged to be actuated by keys 24, in the slots 23, the second pair is actuated by the key |43 also in a slot 23 and the third pair being arranged for operation by the longest key 2G in one of the slots 25.v The cross-sectional view of Fig, 5 exposes the third pair of contacts which are to be actuated by the key 26, These contacts Si and 62 are respectively mounted on resilient contact springs ,63 and Si which are respectively attached to the back end of the block 4I and project through a slot 65 in the block to the other end thereof. 'I'he free end of the upper contact spring is bent upwardly to form a hook 66 the end of which engages the upper surface of the block and limits its own movement downwardly. Considerable space is left, however, for it to vmove upwardly with the contact El when the lower contact spring Se with contact S2 is lifted so that the two contacts engage. The springs and contacts of the other two pairs of contacts are the same as the pair just described. `To enable the keys 2, N3 and 26 to move the lower contact of each pair upwardly, each lower contact spring is provided with" a block preferably formed of insulating material and provided with a beveled end. The block on contact spring @3 is shown at til and the blocks onthe other two lower contact springs are shown atdd and |33. (See Figs. 5 and l2.) 1n Fig. 5, block tl is partly broken away to show block 58 which in thisvview is directly behind it. The block tls-stands in the path of movement of key 26;r the block 68 stands in the path of movement of the key i d3 and the block l 33 stands in the path of` movement of key 24. The purpose of the notch idd' in key M3 is to permit key its to pass block 933, without engaging it. The dial 2@ revolves in a clockwise direction, as viewed in Fig, 12, and as the respective keys reach the blocks 6l, 68, i353, they engage the beveled surfaces thereof to lift'the respective contacts.

It is of considerable advantage to mount these three pairs of contacts in the common block el since they may in this manner be together adjusted in relation to the dial, and their relation to each other remains unchanged. The circuits operated by each of these three pairs of contacts will be described in connection with the connec tion diagram Fig. 12.

The manner oi mounting the block 4l on the panel d' is illustrated in Fig. 13. This View is taken through the center line of a boss 5" projecting from the back surface of the panel. The block is attached to the end surface of this boss l" 'oy screws di' projecting through holes di The holes are made larger than the screws so as to permit a range of movement of the screws laterally of the holes. When assembling the block upon the panel, the blodk is loosely held by the screws against the end surface of the boss until the block is adjusted, within the range of lateral movement of the screws, so as to simulianeously position the three pairs of contacts in their proper relation to the dial. The screws are then tightened and the block is held stationary 'in this position. 1

mounted below the driving motor by bearings at each end thereof, One bearing is located in a lug i3 projecting from one side of the panel and the other bearing is located in a bearing member 'M attached to a lug projecting from the other side of the panel.

Fig. 9 is a front perspective of the drum illustrating the ratchet wheel l2 at one end of the shaft 'i0 and the group of discs adjacent to each other and next to the .ratchet wheel. The discs are illustrated, in this gure; with all their rim sections. in place; the desired sections being broken off just before the drum is placed into the controller. The discs and ratchet wheel may be attached to the shaft 'I0 in any convenient manner. In the illustrated drum, the ratchet wheel is fastened to shaft le by a set screw and the discs are mounted on the square portion of the shaft, are spaced from each other by spacing collars il' which may or may not be integral with the discs, and are held in xed position by a collar li" placed against the last disc and fastened to the shaft by a set screw.

Fig. lil discloses an end view of one of the discs, for example,- disc H59. The disc is made of an insulating material, preferably a molded insulating compound such as a phenolic condensation product with a filler. A number of radial slots divide the rim of the disc into sections. Directly under the rim the disc is reduced in thickness so that any one of the rim sections may be readily broken off. The disc 85a is shown with one such section broken away. The purposecontacts 98 and lill engage and close an electric circuit.

For the purpose of rotating the drum in response to the contact actuations by the dial keys, a solenoid with a pawl and ratchet mechanism is provided. Thismechanisrn may be described by reference to Figs. 3 and 6. It comprises a pawl i6 pivotally mounted on a crank 'il which in turn is pivoted on the shaft l0, and a solenoid having its armature plunger attached to the free end of the crank for intermittently raising it. This solenoid includes a laminated rectangular core i8 -which is pivotally suspended on a lug i9, by a pin till, at one side of the dial. A coil 8l in the core raises an armature 82 when it is energized and releases it when deenergized. The armature is connected to the crank by a pin S3.

When the coil @l is energized by the closure o f contacts operated by the dial, it draws the armature 32 upwardly, thereby lifting the crank ll, causing it to rotate clockwise about the shaft lil. The pawl it slides over the teeth of the wheel 'l2 during this clockwise movement. When coil Si is deenergized, armature 82 and crank il move downwardly and during the downward movement pawl 'ifi engages a tooth of wheel l2, thus eecting a turning movement of the drum. A spring ill wound about the pivot pin @E for the pawl, and having its ends respectively attached to the pawl Aand crank, maintains the free end of the pawl in contact with the ratchet wheel l2 and causes it to engage a tooth face when the crank Td moves counter-clockwise. n the present arrangement the ratchet wheel i2 together with-the shaft 19 and discs 1| are rotated on the counter-clockwise movement ofthe crank when the coil 9| becomes deenergized and the crank drops due to its'own weight and that of the armature 82 connected to it. 'I'his is contrary to the usual arrangement of ratchets but has a denite advantage. The advantage thereof is that since the weight ofthe crank and armatureis constant a uniform force is available for turning the drum at each deenergization of the coil 8|.

In order'` to'limit the movement of the drum to a predetermined arc at each operation, an improved spring assembly is provided. This spring assembly may be described by reference to Figures 3, 6 and 7. It comprises a leaf spring 86 attached at one end to a lug 8l on the shelf 56 by screws 89. It extends upwardly at a slight angle to the vertical, and at its upper end itis provided with a shoulder 89 extending across 'a portion of its width and an extension 9| extending across thev remainder of its width. The extension 9i is bent approximately at right angles to the body of the spring and supports at its end, a second spring 92 which extends back along the extension 9|, its end rising slightly above the extension and ending slightly forward of the shoulder 89. As best shown in Fig. 3, the upper end of leaf spring 96 terminates adjacent to the free end of pawl 16. Pawl i6 is provided with a notch which forms a forward end or nose 93 adapted to engage the teeth of ratchet wheel 12 and an abutment, or end surface 93', spaced back from the end of nose 93. Pawl 'i6 is narrower in width than ratchet wheel 'l2 and when in the position shown in Figs. 3 and 6, which may be termed its normal position, abutment 93' engages the top edge of leaf spring 86 at one side of spring extension 9| with nose 93 projecting over and beyond such top edge. At this time, nose 93lies along side the second spring 92 with its end in line with the end thereof and with the end of nose 93 and the end of spring 92 both in engagement with the same Jtooth of the ratchet wheel The function of this spring assembly is threefold. First, it prevents a clockwise rotation of the-ratchet wheel when the coil 9| is energized to move the pawl 84 clockwise, second, on return movement of the pawl, it prevents a movement of the drum due to its own momentum beyond the point to which it is carried by the pawl, and thirdly, it limits the travel of the pawl on the return movement. .When the pawl 'i6 moves clockwise, due to the energization of coil 8|, the forward en'd lof the spring 92 which is in engage-l ment with the face of a tooth on the ratchet wheel 12, prevents this wheel being dragged by the pawl 16 which slides over the teeth of the .ratchet wheel during this movement. Upon the return movement of the pawl during which it engages a tooth face and rotates the ratchet wheel and drum, it moves toward the shoulder 89. At the end of its movement, its forward end 93v is directly over the shoulder 89 and lis thereby locked into the tooth notch in which it happens to be. Any tendency on the part of the drum, therefore, to move beyond the position to which it is carried by the pawl is overcome and it is locked into that position. At this moment the end surface 93 of pawl 16 engages the upper endof spring 86. This stops the return movement o f the pawl, the spring thereby forming a resilient stop for limiting the return movement of the pawl and crank.

.The combining of the two springs 86 and in the manner described greatly simplifies the ad- `iustment of the shoulder 99 and the spring 92 with respect to pawl 16 and ratchet wheel'iz. The spring 92 is made of such length that when abutment 99 on pawl 16 is in engagement with the upper end of spring 86, as shown in Fig. 6, the end of spring 92 is in line with the free end of pawl 16. This forms a simple means for obtaining initially a correct relationship between the cooperating pawl and the spring surfaces., Spring 96 can be bent forward or backward to adjust it to the desired position with respect to ratchet wheel E2 so that when the drum is actuated. return movement of the pawl will be stopped to position correctly the ratchet wheel and the drum discs; and when thus adjusted, it will be noted that since springs 96 and 92 form a unitary structure and are moved simultaneously, the relationship between the upper end of spring 96, which is engaged by pawl l, and the end. of spring 92 will be always maintained.

As stated abovey the controller drum controls the tramo signal circuits by actuating certain contacts. The contacts operated by the drum areillustrated in detail in Figs. 3, 8 and 11. A contact carrying block 95 of suitable insulating material is mounted underneath the controller drum and is supported in back of and in spaced relation to panel 5' by a suitable number of bolts H0 which thread into bosses on block 95 and clamp the bosses against lugs |09 projecting from the face of panel 6. In shelf 66, directly beneath block 96, is a rectangular opening H2 which exvtelns of the type in which a controller ofthe character embodying my' invention is used, the number of contact arms which may be required varies according to the particular conditions to be taken care of in any particular instance and block 95 is made long enough toprovide a sulcient number of contact arm receiving grooves, or channels, to take care of maximum requirements. The contact arms are indicated at 91 and in the present instance, as will be seen from Fig. 3, seven contact arms 91 located in the seven lefthand contact arm receiving grooves are shown. Each contact arm 91 comprises a at strip of metal, for example, a sheet metal stamping, ofsuitable length provided with a contact ilil spaced inwardly from one end and a contact |02 at the other end. In each contact arm, just above contact |02, is an opening |01. The stationary contacts 99 and 99 are mounted in rows above and below the dividing walls 96 and in line with the channel between each pair of walls 96. Contacts 99 are mounted in the upper contact and terminal receiving portion 95b of block 95 and comprise contact heads carried by threaded bolts 99a which project'throughportion 96h and are provided on their inner ends 4with terminal bolts 98". Stationary contacts 99 are carried by contact strips H9 fastened to contact and terminal carrying portion 95 by screws |26. The lower vends of contact strips H9 project below block 95 and through opening Il! in shelf 66 terminating below the lower face of the shelf. The contacts |0| 1I and it on each contact arm @il cooperate respectively with a contact e@ and a contact QS. Each contact arm @7J is held resiliently in position to cooperate with. the stationary contacts by a key tilt which is provided with a head iill and a bit fitti. As best shown in Fig. e, key it@ eztends through the opening lili! in the contact arm and through a keyhole shaped opening itil in block 95, the bit lite on the end of the key engaging a notch in the rear face oi the blo k. A inelical spring ille is mounted on the key between the head mit and the arrn til. 'For simplicity in manuiacture, the key |03 may be stamped out of sheet metal. In assembling a contact on the block, the forward end oi the key is inserted by simply hooking the bit end of the key through the hole lill in the arm and thereafter moving the head end of the key upwardly until it is perpendicular to the arm. The bit end of the key is then moved through the keyhole shaped opening |08 in the block afterwhich the key is turned 90 and the bit |05 hooked into a suitable notch in the back surface of the block. The contact arm with its contacts is then held against the stationary contacts by the pressure of the spring |06 which is under compression between the head |04 and the contact arm. This method of holding the contact arm enables a quick removal of the arm for replacement or contact examination. When assembled, contact |02 is held rmly in engagement with contact 99 and contact IM is mved into and out of engagement with contact 9i. `S'I'hus each contact arm functions to connect andl disconnect its corresponding pair of contacts 98 and 99.

Mounted on terminal carrying portion 95d of block 95 are angularly shaped terminal strips 62H, each having one arm fastened to the underside of portion 95d by terminal screws |22 and the other arm extending down through opening H2 in shelf 55 in parallel relation to strips H9.

In order to control the engagement of the movable contacts |D| with the stationary contacts et the contact arms 91 extend upwardly so that their ends ride on the rims of the discs 1I and |55 to i539 inclusive. In the positions of the drum, in which a disc presents an unbroken rim to the end of a contact arm 97, the contact IUI on such arm is out of engagement with the corresponding stationary contact 98. When a disc is turned by the rotation of the drum to a position where a broken away portion of its rim is brought into line with the end of a contact arm, the contact arm moves inwardly to bring its contact loi into engagement with a stationary contact @il For the purpose of providing a convenient connection between the Vcontacts on the block 35 and the conductors in cable lli, there is provided a terminal board fastened by means of screws Md, over opening M2.

The terminal board H3 is a rectangular board provided on its inner surface with a channel H5 extending lengthwise of the board from end to end and with grooves il@ not as deep as the channel, extending across the Width of the board at right angles to the channel H5. Terminals i il comprising resilient leaves are attached to the board by means of eyelets ||8 into which conductors from the cable l@ are soldered. The leaves of the terminals extend outwardly of the grooves and over and above the lsurface of the channel. When the board is attached to the under side ci the shelf 56 these leaves engage the ends of terminal strips i i9 and lZi which extend through the opening in the shelf.

The terminals iii on the board |53 are arranged in tivo rows along the opposite sides of the board, each row extending over and above the charniel surface ll and engaging the two rows of terminal strips itil and tt projecting down from the block 95. Terminals i lll are connected to the terminals on switchboard il by cable i@ and the terminals on the switchboard are connected to the outgoing circuits oi cables li and Terminal board is provided with a number of terminals iii7 sumcient to make the required number of connections to terminal strips i i@ and i2 i. The number required and the arrangement varies in accordance with the reduirementstin any particular case.

With this arrangement, it will be seen that a; timer as a unit may be completely disconnected electrically by unscrewing the screws iid and removing terminal board H3, a thing which disturbs none of the wiring of the timer nor of the cable connections. This a feature in the construction which is of substantial importance in that it enables the timer to be wired complete as a unit after which itW may be mounted in casing 5 and connected in the circuit by merely attach- 25 ing a terminal board H3. Likewise, switchboard 9 and terminal board H3 may be wired together as a unit, the wires being made into the cable l0.

In constructing a controller for a particular application, the timer may be assembled except 30 for the drum and the contact arms 91, and completely wired. Following' this, a drum may be made up by taking a shaft EEB and mounting thereon the required number or discs with the correct segments broken out and a ratchet wheel having the required number of ratchet teeth and mounted in place in the timer. And then the required number o contact arms el may be slipped into place. This completes thetimer. The timer may be now mounted in the controller casing. 40

Next, a switchboard 9 and a terminal board ||3 may be made up with the required number and arrangement of terminals and wired together as a unit and assembled in the controller casing, the terminal board being attached to the shelf to make the electrical connections. to the timer. This completes the controller, it being now ready to be wired into the system in which it is to be used. it is wired into the system through the terminal connections on the `iront of the switchboard t as shown in Fig. l.

Referring now to the diagram of connections. Fig. l2, we may trace the circuit connections and the sequence of operations of the apparatus just described. This ngnre discloses e. circuit diagram including a perspective view of the dial 2li with its keys and a skeleton view of the contacts operated thereby. A conventional tramo signal having the well known three color signals designated i by the letters R, A, and G is shown. Two faces of this unit are illustrated one for each of two intersecting streets.

Current is supplied to the controller from a 1ocal source through a conductor i25 and from a second source S through a conductor iZG which is common to a group of controllers. The conductor 025 is permanently connected to a conductor 32S and through the panel switch to a conductor 52d.

Conductor |128, which is permanently energized carries current to contact i3d which is one of the stationary contacts in the block lli. 'The cooperating contact of this pair :is contact lill mounted on the spring 532. The contacts i3d-tt are the pair of contacts in the block il the control drum except one.

which is nearest to the dial' 2,0. lThe lower contact |3| of this pair is lifted into engagement with upper contact |30 by each key 261 as the dial rotates.

Contacts |30 and |3| are in a circuit which includes the drum operating coil 3| and which may be termed the normal operating circuit. This circuit may be traced as follows: Source conductor |25, conductor |28, contacts |30-|3I, contact arm |32, conductor |35, set of contacts 99-|0291-08-|0| (as illustrated in Fig. 8) controlled by drum disc 1|, conductor |33, conductor |31, switch 33, conductor |30, coil 3|, to ground. Contact arm 01 controlled by disc 1| is in closed circuit position for all positions of To this end, all but one of the segments of disc 1| are broken away. In the present instance, ratchet wheel 12 has six teeth so thatthe drum has six positions, in ve of which such contact arm is in closed circuit position and in the sixth in open circuit position. When contact 3| is moved into engagement with contact |30 by a key 24 at a time when the contact arm controlled by disc 1| is in closed position, the normal operating circuit through coil 8| is closed, thus energizing coil 8| and advancing the drum one step. Thus successive operations of the contacts |30|3| by the keys 24 result in a step-by-step movement of the drum at intervals Adetermined by the spacings of the keys 20. However, if when contact |3| is moved into engagement with contact |30,.the contact arm controlled by disc 1| is in open circuit position, the normal operating circuit is not closed, and hence the drum is not advanced. Now, to eect a further movement of the drum, there is provided through coil 8| a second circuit, which may be termed a local synchronizing circuit, which circuit is in shunt with the normal operatingcircuit and includes thev contacts |40 andl |4| which are removed into engagement by local synchronizing key |43. When during rotation of dial 20, key |43 engages block 68 to move contacts |4| into engagement with contact |40, a circuit vis closed through coil 8| as follows: From source conductor |25 through switch 32, conductor |29, switch I8, conductor |46, contacts |40-|4|, contact spring |42, conductor |36, conductor |31, switch 33, conductor |38 and coil 8| `to ground. Closing of this circuit energizes coil 8| and causes the drum to be advanced one step. It will thus be seen that under normal operating conditions during each complete rotation of 'dial 20, the drum is given one complete turn in six successive steps, one step, which may be considered the first step, being effected by local synchronizing key |43 and the ve following steps being efected by the ve keys 24. The contact arms actuated by drum discs |54 to |59 inclusive control the circuits R., Ri, G, G1, and

A, A1 to the signal lamps, and discs |54--I59 inclusive are arranged in the drum controller with their broken away sections located in such rela-1 tion to each other that with successive actuations of coil 8|, rst by local synchronizing key |43 and then by the ve keys 24, the desired sequence of operation of the lamps is effected. And the keys |43-24 'are spaced apart around the dial to give the desired duration of signals for each drum position. Thus there is a denite correct relationship between the drum position and the dial position which must be maintained for correct operation of the signal lamps. This correct relationship obtains as long as the drum position is in such relationship to the, dial position that key |43 operates contacts |4|, |40 at a time when drum disc li hasmoved its contact arm 91 to open circuitposition; that is, when the drum disc is moved to such position by the key 243 just in advance of key |03. If the controller is started l into operation with the drum and the dial not in correct relationship relatively to each other, then if it so happens that the drum is in the position in which contact arm 0l is in open circuit position, no energization of coil 0| and operation of the drum will occur until key |53 actuates contacts |4I, |00, keys 2d being ineffective to close the normal operating circuit since this circuit is opened by the drum disc 1I. On the other hand, if the controller is started into operation with the drum and dial not in correct relative relationship but at a time when drum disc 1| is in a position such that contact arm 01 is in closed circuit position, then keys 20 will effect operation of the drum until contact arm 81 is moved to open circuit position after which no further operation of the drum can occur until key |03 actuates its contacts Ml, |40. Thus it will be seen that if at any time the-controller is started up when the drum and dial are not in correct relationship relatively to each other, or if at any time during operation the drum and dial should for any reason get out of such correct Irelative relationship, they will be quickly brought into correct relationship during the first complete rotation'of dial 20.

For automatic operation as described above,

lswitch 33 is in the position shown in Fig. l2,

wherein it connects conductor |38 to conductor |31. To shift the signals from automatic to manual control,.switch 33 is moved to connect conductor 38 to conductor I3. This connects coil 8| in circuit with push button I2 so that the drum may be turned manually step by step by successivelyclosing switch I2. At any time, the signals may be shifted back to automatic control by moving switch 33 back to the Fig. 12 position. And during the first complete rotation of dial 20, the dial and drum will be brought automatically into correct synchronous relationship and thereafter maintained in such relationship as already explained.

The second source of power S, is used for synchronizing a group of controllers with each other and with a master controller |21. The master controller |21 is diagrammatically illustrated as being provided with a cam |50 which periodically opens a switch |5I. The switch |5| is connected in acircuit which includes contacts 6| and 62 and the field winding 05 of motor 02 which circuit may be traced as follows: Source S, switch |5I, conductor |26, conductor |52, arm 64, contacts 62, 6|, and conductor |53. Switch |5| is normally closed and is opened periodically once during each complete rotation of cam |50. Contacts 5|, 62 are normally separated and are closed once during each complete rotation of dial 20 by key 26 engaging block 61. During operation, if the controller at an intersection is in synchronism with the master controller, the time is such that at the instant key 26 effects a closing of contacts 6|,-62, cam |50 eiects an opening of switch |5| with the result that the circuit through motor winding |45 is not completed and the intersection controller continues to operate in a normal manner. If, however, when key 26 effects a closing of contacts 6I, 62, cam |50 is in a position such that switch |5| is closed, (which indicates that the intersection controller is out of the desired time relationship with the master controller), the circuit through motor windings 45 is completed and motorV 42 is stopped due to the eid 45 opposing field 44, and when thus stopped, contacts 6|, 62 are held closed by key 26. The circuit thus established through iield winding 45 remains closed until cam |50 has moved to a position to permit switch |5| to open whereupon motor 42 willv start operating and move key 26 to permit contacts 6|, 62 to open.A This means that the dial v2|) is again started in synchronous relation to the master controller. Each controller of a group being similarly equipped will actuate a similar pair of contacts at an instant during its operating cycle. If it is in synchronism it will continue to operate. If it is out of synchronism, it will stop and will start at the instant atwhich |5| is opened. The positioning of the key 26 in the slots 25 will therefore determine the relationship in which the controller. and the signals operated thereby will be maintained by the above mechanism, in relationship to other controllers in the system. y

The drum illustrated in the example controller is provided with seven discs of which disc 'Isl regulates the position of the drum relatively to the dial and the discs |54 to |59 control the red, green, and amber signals for two intersecting highways. As above stated, the contacts operated by each disc are normally separated and closed in only one or more positions of the drum, dependent upon the signalling cycle. The current for the signals is received through the switch 32, conductor |29, contacts of the switch I3, and a conductor |60 which is connected to each of the contacts 98 under the discs |54 to |53. When the discs are in proper position, the proper contacts close and the corresponding signals are energized through the cable The switch is provided to control-the circuits of the trafc signals and of a flashing mechanism to make it possible to operate only the amber signals and to operate them as periodically ashing signals. This type of operation ispractical during periods of light trailic. In the position Shown in rig. 12, th'e switch is in a position to connect the amber conductors A and Al to the contacts of the drum controllerl so that these signals are under control of the discs |58 and |59. When the switch is thrown to its second position, the conductor |29 which supplies the local current for operating the signals is separated from conductors |46 and |60 and no current flows to the drum contacts 99 through the conductor |60. Simultaneously, the conductors A and A1 are connected to a conductor |48. This conductor. |48 is connected to a flashing mechanism mounted on the supporting plate 46 of the driving motor. l

This iashing mechanism comprises a stationary contact |6| mounted on a contact arm |62 and a movable contact |63 mounted on a contact arm |64. The contact arms are both mounted on a contact block |65 which is suitably attached to the motor supporting plate 46. The arm |64 is Ipivoted to the block at its back end land is bent at right angles at its forward end to provide a nose |66. 'Ihe end of this nose |66 rides on the periphery of a star wheel |61.v When the star wheel rotates the nose |66 riding the periphery of the wheel causes an intermittent engagement of the contacts |6|, |63. e Conductor |48 is connected to contact arm |64.` Contact |6| is connected by a conductor |68 to the cur-r rent supply conductor |29.

In operation, therefore, when the switch I8 is thrown to its second position it shuts oi ,the current supply to the green and red lamps of the trailic signal unit and connects the amber lamps to the current supply through the flashing mechanism so that as star wheel |61 rotates, it operates contacts |6|, |63 to intermittently energize v the amber lamps. Simultaneously, switch I8 disconnects conductor |46 and the resynchronizing contact |40 from the current supply, thus opening the local synchronizing circuit. After this circuit has been opened, the drum will continu'to be advanced by keys 24, operating contacts |30, |3| until it reaches the position at which disc 'H opens the drum advance coil circuit. The drum will then remain in that position until switch |8 is again thrown to normal operating position.

Thev panel switches 32 and 34 may be opened respectively to extinguish the signal lamps or to stop the dial motor. When switch 32 is opened, the source of current to conductor |29 is interrupted whereby the continuing movement of the dial will effect a movement of the drum up to the main street green position at whichthe disk 1| opens the drum advance coil circuit. The drum then remains stationary. This operation is the same as takes place when switch I8 is operated to break the same circuit, by separating conductors |46 and |29, at the switch contacts.

The switch 34 may be opened to stop the`dial vat any chosen instance. By merely opening the switch 34 during the amber signal period, for example, it is possible to obtain a steady amber indication instead of a flashing amber indication as is the case when switch i6 is operated to its second position. An opening of both switches 32 and 34 effects a complete shutdown of the controller.

What I claim as new and desire to secure by Letters Patent of the United :States is:

l. A traffic signal timer having contacts, a drum controller for operating said contacts, and means for rotating said drum controller step by step includingr a ratchet wheel mounted on said drum controller, a pawl'operable to rotate said wheel when moving in one direction and to slide over the teeth of said wheel when moving in the other direction, and means for holding said drum controller in the position to which it is moved by said pawl comprising a spring provided with a shoulder arranged to engage and hold the pawl in engagement with the said ratchet wheel when said pawl reaches the end oi' its movement when rotating said drum controller, and a second spring supported by said rst spring arranged to engage the face of a tooth on said ratchet wheel whereby said drum controller is prevented from overrunning its position in the rst instance and is prevented from moving in a reverse direction with the pawl when the latter slides over the periphery of said ratchet wheel.

2. A traffic signal timer comprising a rotatable drum, a ratchet wheel attached to said drum, a pawl cooperating with said ratchet wheel, means for reciprocating said pawl to advance said ratchet wheel and drum to successive positions, and means for retaining said drum in each of Y its positions including a spring which engages the ratchet wheel to hold it against rotation in one direction and against which the pawl strikes for simultaneously stopping said pawl and holding it in engagement with said ratchet wheel to prevent rotation of said ratchet wheel in the other y direction.

3. In a trailic signal timer, the combination of a panel, an opening therein, a dial -mounted in said opening, a motor arranged to rotate said dial, a group of switch contacts operated by said dial mounted on the back of said panel above said dial, a drum controller provided with a cam shaft mounted horizontally below said dial, a solenoid mounted on said panel and provided with a movable4 plunger, means connecting the plungento said cam shaft, electric conductors connecting. said solenoid to said dialoperated contacts, and ar second group of contacts operable by said cam sh-aft'mounted on said panel below said drum controller.

d. In a tramo signal timer, the combination of a panel provided with a base, a dial mounted on said panel, a motor mounted on said panel and connected to drive said dial, switch contacts mounted 'on said panel and intermittently operable by said dial, a drum controller shaft mounted on said panel below said dial, cams on said shaft, means for moving said cam shaft, electric conductors connected between said means and said dial-operated contacts and a group of contacts mounted on the base of said timer in operating relation to said cam shaft.

5. In a traii'lc signal timer, the combination of 4a panel provided with an opening, a yoke attached to said panel and disposed across said opening, a dial mounted in said opening and on said yoke, a motor mounted on said yoke and connected to operate said dial, a contact control drum mounted on said panel below said motor, means for operating said drum, keys in said dial the position of which may be adjusted, switching contacts operated by said keys and electric conductors connected between said switching contacts and said drum operating means.`

6. .In a tramo signal timer, the combination of a panel, a dial supported on said panel, means for rotating the dial, a plurality of spaced actuating keys carried by the dial and arranged to move in dierent paths when the dial rotates, a mounting block, switch contacts mounted in ixed relation to eachother on said mounting block and having parts which stand in the paths of movement of said actuating lreys whereby when the dial rotates, the keys eiiect operations o i said contacts, and means ier supporting the block on said panel to bring all said contacts into fixed operative relation to said. actuating keys.

7. In a traido signal tirrrer, the combination of a signal controller, a dial, means for rotating said dial, a pair of contacts operated by said dial and adapted to be connected to control the oration of said signal controller, a 1second pair of contacts operated by said dial, and a common block ior supporting said two pairs ci contacts in definite relation relatively to each other and in relation to said dial, whereby the positioning of said block simultaneously determines the operating relationship between the said several pairs oi contacts and the dial.

. In a tralc signal controller, the combination of a support, a signal controlling member roe' tatably mounted on the support and adapted to effect a cycle of operations, a motor for rotating said member, said motor being adjustable to different positions to enact rotation of said inem2 ber at rates' corresponding to diiierent cycle lengths, and indicating means positioned bythe positioning -of said motor for indicating the cycle length for which the motor is positioned.

9. In a trame signal controller, the 'combination of a support, a'signal controlling member rotatably mounted on the support and adapted to eiect a cycle of operations, a motor for rotating said member mounted at the rear of said support and adjustable to different msitions to effect ro assenso tation` of said member at rates corresponding to diierent cycle lengths, and indicating means positioned by the positioning of said motor and visible from the front of the support for indicating the cycle length for which'the motor is positioned.

l0. In a trafc signal controller, the combina'- t-ion of a support, a shaft rotatably mounted on the support, a signal controlling member mounted on the shaft and adapted when rotated to eiect a cycle of operations, a frame, a motor having a .shaft carried by the frame, gears connecting said shafts throughwhich the motor drives'the signal controlling member, adjustable means mounting the frame on the support whereby gears of diierent sizes may be utilized between the Shafts to eil'ect rotation of said signal controlling member at rates corresponding to different cycle lengths, and indicating means positioned by the positioning of said frame for indicating the cycle length for which the frame is positioned.

11. In a traic signal controller, the combination oi' a support, a. shaft rotatably mounted on the support, a signal controlling member mounted on the shaft and adapted to be rotated to eiect a cycle of operations, a motor having a shaft, a pair of gears between said shafts through which the motor drives the signal controlling member, said motor being adjustable to vary the distance between said shafts whereby gears of diierent sizes may be utilized between the shafts to effect rotation of said signal controlling member at rates corresponding to different cycle lengths, and indicating means positionedby the positioning of said motor for indicating the cycle length for which the motor is positioned.

l2. A controller having a contact operating drum, means for imparting step by step turning movementto the drum. comprising a toothedv ratchet wheel connected to the drum, a pawl engaging teeth on the ratchet wheel, means for lifting the pawl relatively to the ratchet wheel to bring the pawl into engagement with a tooth of the ratchet wheel and then release said pawl to permit it to return to eiect a movement of the ratchet Wheel, and a spring member having a surface against which the pawl strikes at the end of its return movement to arrest downward movement of the pawl and further turning of the ratchet wheel and a part which engages a tooth of the ratchet wheel to prevent reverse turningA movement of the ratchet wheel.

i3. A controller having a contact operating drum, means for imparting step oy step turning movement to the drum comprising a toothed ratchet wheel connected to the drum, a pavvl en= gaging teeth on the ratchet wheel, means for lifting the pawl relatively to the ratchet wheel to bring the pawl into engagement with a tooth of the ratchet wheel and then release said pawl to permit it to .return to eldest movement oi the ratchet wheel, and a spring member having an end against which an under part oi the pawl strikes at the end ci its return movement to yieldrd ably arrest the movement oi the parli and further turning of the ratchet wheel and an angularly extending part which engages a tooth of the ratchet wheel to prevent reverse turning movem ment of the ratchet wheel.

lli, A controller having aA contact operating drum, means for imparting step by step turning movement to the drinn comprising a toothed ratchet wheel connected to the drum, a pawl engaging teeth on the vratchet wheel, said pawl being narrower than the ratchet teeth, means for litingthe pawl relatively to the ratchet wheel to bring the pawl into engagement with a tooth of the ratchet wheel and then release the pawl to permit it to return to effect a movement of the ratchet wheel, and a spring member having an extension against which an under part of the pawl strikes at the end of its return movement to yieldably arrest the movement of the pawl and further turning of the ratchet wheel and an angnularly extending part which engages a tooth of the ratchet wheel at the side of the pawl to prevent reverse turning movement of the ratchet wheel.

15. In a traic signal timer, a support, a cam shaft mounted on the support transversely to a surface thereof and having a series of cams removably mounted thereon, a contact block mounted on the support transversely of such surface and directly adjacent to said shaft, said sup- I port having a transversely extending opening adjacent to said block, contact arms removably mounted on said block having ends which engage said cams and ends presented to said opening, a connection block fastened to the support having terminal contacts, and means connecting said last named ends to said terminal contacts through said opening.

16. In a traflic signal timer, a support coniprisinga panel and a shelf which extends at an angle to the panel and is provided with an opening, a contact actuating member mounted on the support, a motor mounted on thesupport and connected to drive the contact actuating member, a drum controller mounted on the support transversely thereof above the shelf, a contact block mounted on the support adjacent -to said cony troller, contact arms mounted on the contact block having ends which engage with the drum controller and ends which stand in line with said shelf opening, and a connection block which is fastened to the shelf and has terminal contacts connected to said last named contact arm through said opening.

17. In a traflic signal timer, a support, a cam carrying shaft detachably mounted on and extending across the support in spaced relation thereto, cam disks removably mounted on said shaft, said shaft being of a length to have placed thereon the maximum number of cam disks which may be required in the use of the controller, a contact block mounted on the support adjacent to said shaft, contact arms detachably mounted on said contact block, said block being of a length to have placed thereon contact arms corresponding in number to the number of cam disks mounted on said-shaft, said contact arms presenting one end to said cams and said support presented to said opening when the terminal block is mounted overthe opening.

18. In a traffic signal timer, a support, a drum controller comprising a plurality of cams mounted on the support, said support having an opening which extends throughout the length of said drum controller, a block mounted on the support I adjacent to said opening, contact strips fixed on said block with one end in line with said opening, contact arms detachably connected to said block having one end in engagement with said cams and the other end in engagement with said contact strips, a second block detachably connected todisks carried by the shaft; a Second unitary structure mounted on the support comprising a block having thereon detachable contact arms having ends presented to the cam disks and a third unitary structure mounted on the support comprising a block and terminal contacts carried thereby which when such third unitary structureis attached to the support are electrically connected to said contact arms: each of said structures being adapted to be applied to and removed from said support as a unit.

20. In a traffic signal controller, a support, a shaft mounted on the support, cams carried by the shaft, a mounting block adjacent to the shaft, spaced contact buttons carried by the block adjacent to its longitudinal edges, and spring pressed contact fingers detachably xed to the block intermediate between their ends, the outer ends of said fingers pivoting on the contact buttons at one edge of the block and the inner ends of said fingers ridin'g on the cams and being moved by the cams into and out of engagement with the contact buttons at the other edge of said block.

21. In a traffic signal contr01ler,`a support, a shaft mounted on the support, a series of removable cams on the shaft, a mounting block adjacent to the shaft having-a series of spaced openings and a row of contact buttons above and below the openings, contact fingers the outer end of which engage the lower row of contact buttons, and the inner ends of which ride on the cams, keys which extend through openings in said fingers and detachably fasten in the openings in said block to fasten the fingers to the block, and. springs carried by said keys for holding the fingers in engagement with the lower row of contact buttons and with'the cams, rotation of the cams effecting pivotal movement of the fingers on the lower contact buttons to move the fingers into and out of engagement with the other row of buttons.

RALPH A. REID.

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