Патент USA US2127080код для вставки
Aug. 16, 1938. r J. 1.. BARKER 5- AL 2,127,080 TIMER Filed Jan. 7, 1936 I23456 78 IOIHZ nemmzozlzwms 5 57 30 I Z 10H n 72 66 59 69 12573375 1011.12 TE IT l8 1955555 52123 E 43 7 mm Q20 05 5m: GREEN we IDE QED ' INVENTORJ BY Joan L. bAnksn AND Hmnv A. Wucox'i Gan/M4,, mA57% T TORNE Y.’ Patented Aug. 16, 1938 2,127,080 UUNITED STATES PATENT OFFICE 2,127,080 TIMER John L. Barker, White Plains, and Harry A. Wil cox, Bronxville, N. Y., assignors to Automatic Signal Corporation, New York, N. Y., a corpo ration of Delaware Application January 7, 1936, Serial No. 57,882‘ 4 Claims. (Cl. 175-375) This invention relates to a functionally and the device and operation thereof, and to the ac structurally improved timing device capable of companying drawing which shows an embodiment use in many associations butlprimarily designed of the timer in a trailic signal controller for use for use in traf?c control systems and the like. at the intersection of interfering traiiic lanes in 5 Generally it is an object of the invention to pro systems of the tra?lc actuated type. vide means by which ‘an accurately timed period, A system of this character may be composed whose duration is adjustable at will, will elapse of three parts: a vehicle detecting or respon after the initiation of one action before a result sive device arranged to detect tra?lc approach ing action takes place. ing on the cross street vehicle lanes, a signal con 10 An additional object is to provide a time con trol mechanism comprising the timer device, and trolled multi-position switch having a large num a right of way indicating device to inform traflic ber of contact positions independently adjust in the intersecting lanes when to go and when able as to timing for timing a plurality of opera to stop. tions or signalling indications in sequence. The vehicle actuated means or detecting device 15 Another object is to provide electrical timing may be any of several types. It may satisfac apparatus of this character in which a compen torily be a mechanical switch, or light or sound sation is provided in the design of the timer for sensitive means, or electro-magnetic, or electro the effect of line voltage fluctuation on the ac curacy of timed periods. 20 Still another object is to provide an electrical timing apparatus in which an adjustment may be made while constructing said apparatus to elim ) inate errors in the periods timed due to improp~ static or other means. A signal device for indicating right of way to the several lanes may be composed of conven tionally colored green or go, amber or caution, and red or stop signal lights which are illumin ated by circuits from the control mechanism. The function of the control mechanism is to time the periods of the different signal indica tions and to govern changes of indications, its op which the timing is accomplished through varia eration being initiated or modi?ed by actuation tion of the voltage between cathode and anode - of the tramc responsive devices, so that the tim of a multi-electrode gas discharge tube and the ing mechanism and the traffic responsive devices 30 timing is adjusted by varying the voltage between jointly control accord of right of way. 30 ' the cathode and a grid in said tube. One form of the invention will be described A further object is the provision of a timer in in detail in connection with the accompanying which the timing depends on the charging of a ?gure of drawing which illustrates a signal con condenser to the gas breakdown voltage of a trol apparatus and a circuit diagram thereof for 35 multi-electrode gaseous discharge tube andfin governing the changes and duration of signal which the breakdown voltage and corresponding indications to the intersecting tra?ic lanes, and 35 timing limit can be _ adjusted by varying the which operates in conjunction with vehicle de negative bias of the grid in such tube. tectors, as will be disclosed herein. This conAnother object is to provide a multiple posi-. trollcr is particularly designed for installation 40 tion time controlled switch for controlling traffic at the intersection of two tramc lanes of unequal 40 signals through a cycle of right of way indica density. It will be appreciated from the follow tions for a plurality of interfering tra?ic lanes ing description, however, that with alterations in which the standard switch design can be re in the design familiar to those skilled in thegart tained while a considerable number of changes a controller embodying these new features may in the sequence of right of way indications can be constructed for the control of tra?ic at many 45 readily be made by interchanging wires or con other types of intersections, as, for example, in nections on one or more contact positions. tersections where both lanes bear approximately Another object of the invention is to provide a equal tra?ic densities or intersections where more timing apparatus of the above character having than two tra?ic lanes converge or cross one 50 a minimum number of moving parts and elec another. 50 trical parts and comprised of standard units op For purposes of simplicity, the disclosure of erable for long periods free from mechanical the new features of the controller herein will be and/or electrical di?iculties. made in connection with apparatus of the first With these and other objects in mind refer mentioned type, namely, one for the intersection 05 ence is now had to the following description of of a major tra?ic lane with a cross or minor tra?ic erly rated individual standard parts used in said 25 apparatus. Another object is the provision of a timer in 2 2,127,080 lane having a lesser amount of traf?c than the major lane. - A traffic signal controller constructed accord ing to these general principles may be comprised of a timing mechanism, controlled by the tra?ic responsive devices in the cross lane, and a switch ing device, and so arranged that the timing mechanism advances the switching device through a predetermined sequence of signal in 10 dications. If the controller is to operate from alternating, current mains, rectifying means are provided for'supplying direct current for opera tion of the timer. The switching device may be comprised of a telephone rotary type line switch or stepping switch of ordinary design and conventionally shown herein.‘ In the ?gure a switch of this type is shown having six contact banks A, B, C, D, E, F, of 25 contacts each, and having pairs of ro 20 tatable contacting arms or wipers, 44-49 which are advanced step by step cyclically by a magnet 88 which actuates the wipers through suitable pawls and ratchet (not shown). Upon a cycle of energization and de-energization oi the mag 25 net the wipers are advanced one contact position. When‘ one wiper of each pair moves off the 25th contact of the semicircular bank of contacts, the outer wiper of each pair engages the No. I contact, so that the stepping of the wipers 30 through their cycle may be continued inde?nitely. Wipers on banks A, D, E, and F, are of the bridg ing type, that is, they are so designed that when stepping from one contact to the next they will momentarily engage the latter before they are out of engagement with the one from which they are passing, and thus their circuits are held closed during the movement. In the ?gure the wiper arms of the line switch are represented by arrows, which for illustration are shown herein 40 in the llth contact position. Y During the rotation 01' the wipers through one complete cycle of 28 contact positions, the signal display goes through three complete cycles of indications for the control of tra?ic movement. 45 Positions I through 8 comprise the ?rst such cycle; positions 8-l8 the second, and l‘|--25 the by any of numerous well-known means of which one is disclosed here for illustrative purpose. Recti?er tubes 32, 33 supply'unidlrectional cur rent from secondary coils of transformer 84 to leads 35 and 38, and a filter condenser 31- main tains a near constant voltage value. A potenti ometer 48 is connected between said leads. An intermediate point on the potentiometer is . grounded by leads H, 38, and the end of the potentiometer marked, positive is connected by 10 wiper 45 to bank B of the line switch, thence over one of a plurality of timing resistances “~56 to complete a charging circuit over lead 51 to tim ing condenser 58. By lead 58 and the coil of re lay 68 the positive side of the condenser is con 16 nected to the plate ‘ii of three-electrode tube 18, and by leads 8i and 61 the negative side of said condenser is connected to grounded lead 88. Cathode 13 of tube 10 is also connected to ground, and may be of the indirectly heated type in which case it is heated by current from suitable taps “on transformer 34. By means of suitably chosen taps 65 on potentiometer 40 which may be con nected by the several leads 66 to the several con tacts on bank C of the line switch, wiper 46 con trols the grid bias or tube 10 for each contact position, but the grid potential is substantially constant within‘each timing position. Wiper 48 is connected to the grid", and a condenser ‘II is connected between the grid and grounded lead 30. By means of armature 15 and contact 18 on terminating relay 60, circuit may be completed from lead 61 over leads ‘i8, 19, to energize recti?er 80, which may for example be of the dry or cop per sulphide or copper oxide type. This recti?er when energized supplies current to operate motor magnet 85 of the line switch. A condenser 8| across the output oi‘ the ‘recti?er lessens the in tensity of current ?uctuations therein. Ener gization and de-energization of magnet 85 causes the pawls and ratchet of the line switch to ad vance the wipers on each bank one contact posi- tion. In the energized position of magnet 88 a discharge circuit Ior condenser 58 is completed through low resistance 86, armature 81, and con~ tact 88, for resetting said condenser to time the wipers are mounted is thereby reduced propor next interval. tionately. It will be noted that since the 25 Following is a table of wiper contact positions standard contact positions are not evenly divis ,and corresponding signal periods timed in such ible by three, the period or the extra contact positions: ’ position for instance position 28, included in the third cycle, is arranged to be of veryv short dura Wiper contact position tion in order that the third cycle will correspond Signal period to the others. Obviously, additional contact 55 Cycle 1 Cycle 2 Cycle 8 55 banks and wipers might be employed, and a line third. Wear on the rotatable shaft on which the switch with more or fewer contacts in each bank may be used if desired, in order that different signal cycle con?gurations be obtained. Fur ther, the contact positions might be rearranged, some special signal might be displayed in one or more positions, or a greater or lesser number 0! Artery green minimum ........... .. 4, 5, 6 l2, l3, 14 Artery green (skip position) .......................... __ 20, 21, 22 , a Artery green rest. 7 15 Artery yellow. - _ _ 8 18 Side street room. Side street green memory..- - 1 2 9 10 17 13 Side street yellow ________________ ._ 3 11 10 . 24 28 signal cycles during one cycle of the line switch wiper arms might be incorporated. Operation of the signal controller in controlling The timing apparatus may include a three , the signals through a cycle of indications, i! electrode gaseous discharge tube or electron dis switch 88 is in the “automatic" position, follows. charge. tube, a condenser connected between’ the Assume for example, wipers on each bank are plate and ?lament thereof, a source of direct cur engaging contact #4. In this position no con rent for charging said condenser and for pro nection is made on either bank E or bank F of the 70 viding a small grid bias, resistance in the charg rotary line switch, leaving the circuits through ing circuit 01' the ‘condenser, and a terminating lead 89, relay 88, lead 92 to AC power source 8i, 70 relay operated at the end of the timed interval. and through lead 83 relay 85 to AC power lead When the present timer is connected to an 3] disconnected from AC grounded lead 80 at their alternating current supply, direct current for use corresponding wipers l8, 48. Both relays 88 and 75 in the timing circuit may be obtained therefrom 85 will then be de-energized, armature 88 will en 76 2,127,080 gage contact 98 and current will ?ow from lead 3| through lead 96, armature 99, contact 98 lead 91 and side street red light I I9 to AC ground 36, also from lead 96 through armature III'I, contact I08, lead I09, armature III, contact III‘I, artery highway green light II5 to AC "ground 30. The tramc signal will accordingly display green to the artery tra?ic and red to tra?ic on the cross lane. \ " From the recti?erunit 32, 33, meanwhile power is supplied to the potentiometer 40, and over con; tact #4 on bank C and wiper 46 a negative bias is maintained on the grid ‘I2 of tube III, so that no current ?ows in the plate circuit of the tube. From the positive end of the potentiometer 40 and over wiper 45, contact #4 of bank B of the line switch, a circuit is completed over resistance 53, lead 51, condenser 58, and/lead iii to grounded lead 30, charging the condenser at a rate which depends on the capacity of the condenser, the supply voltage, and the resistance of the circuit. Since in the present instance the ?rst two factors are constant, only the last, the quantity of resist ance, is variable and this alone regulates the rate of charging of the condenser. The latter gradu ally acquires across its plates a potential di?er ence approaching the charging voltage, this charging occuring at a rate inversely proportional to the size of resistance 53. The plate ‘II of tube ‘I0 is connected to the positive side oi.’ con denser 58 by lead 59. When the potential di?er ence across the terminals of the condenser has 3 artery green period 4 were found to be some what higher than its rated number of ohms, which would make this period proportionately longer than the time indicated on the rheostat dial operating resistance 53, this error may be elimi nated by connecting the lead from position 4 on bank C to a suitable one of taps 65 so that the ionizing potential of the tube will be decreased to compensate for the higher-than-rated' value of resistance 53. 10 Since raising the grid bias of the tube, which raises the ionization potential of the tube, and in creasing the resistance in the condenser charging circuit both effect a lengthening of the time before operation of relay 60, it will be seen that the value of the charging resistances required for any particular timing period may be sub- - stantially reduced, if desired, by making the grid more negative in that period. The purpose of grid bias adjustment as shown in the ?gure is 20 to furnish a correction to the periods timed by the charging of the condenser through the. re sistances 50-56, to compensate for errors in these resistances. In lieu of having a preset grid bias and providing a rheostat adjustment of the charging circuit as shown, the arrangements 25 could be reversed and a preset charging resistance could be employed along with a manual adjust ment of the gridbias for varying the time inter Vals. 30 Considering once more the operation of the timer, the energy in condenser 56 is dissipated attained a certain value, the potential betweeen in the circuit through relay 60, lead 59, tube ‘I0. the plate and the‘?lament of the tube has reached lead 6| embracing the condenser, when the volt the same value, and eventually the potential ' . age across the latter has reached the ionizing po therebetween is sufficient to ionize the gas in the tential of tube ‘I0 as described above. Relay 35 tube; whereupon the tube suddenly becomes con 60 is energized momentarily and attracts arma ducting and a current su?lcient to energize relay ture 15, which-completes circuit from grounded 60 ?ows. . , leads 30, 61, over contact ‘I6, leads ‘I8, ‘I9 to en 40 This tube is of such a type that the potential of ergize momentarily recti?er 80 or other embodi the grid determines the breakdown or ionizing ' ment of controlled‘ power source, which supplies 40 potential of the tube, but under normal conditions power to operate motor magnet 85 momentarily. of operation after discharge in the tube has com~ Upon being energized and de-energized magnet mencedk the grid has susbtantially no control 85 notches wipers 44-49 inclusive ahead one po 45 over ‘current in the anode-cathode circuit. If direct current is being used in the latter circuit, the discharge in the tube normally is interrupted by opening the external anode-cathode circuit or removing the energy supply therein in some way. 50 If alternating current is being used in the anode cathode circuit of this type of tube, the discharge will cease after the ?rst half cycle when the cur rent reverses. In the present embodiment where direct current is used in the anode-cathode cir cuit, the tube becomes non-conducting when the potential across the condenser is no longer su?i cient to maintain the discharge. From the drawing it may be seen that the I amount of bias applied to grid ‘I2 may be changed 60 by bank C and wiper 46, for each position of the cycle, according to which of taps 65 on the poten tiometer each of the several leads 66 are con- nected. Increasing the negative grid bias in this tube increases its ionizing potential substantially proportionally. Therefore, if the timing con sition into engagement with the contact #5 on their respective contact banks. By the ener 45 gization of magnet 85, armature 81 engages con tact 88 completing a discharge circuit for the condenser 58 through low resistance 86, so that the condenser upon recommencing to be charged 50 ‘in the next interval to be timed will have borne over so little residual charge that the accuracy of the next timed interval will not be adversely a?'ected, and the device will accurately measure time from the instant the charging circuit is 55 closed. In vehicle actuated traillc control systems of this character, vehicle actuatable devices 'in the cross lane approaches to the intersection, of which devices one is shown in the ?gure as ramp 60 I26, as well as push buttons I2I by means of which pedestrians desiring to cross the‘ main street at the intersection may register their pres ence, and any other forms of detectors, may pref erably be connected in parallel, and closure of denser 58 were charged through the same resist ance for varying grid biases, the length of the any of vthese devices closes a circuit between leads I22, I23, completing a circuit from lead I24 thru timing period would over a very considerable relay I25 thence over bank'A of the line switch, range vary substantially directly as the amount of wiper 44 to lead 3| for energizing the relay. Re 70 negative grid bias. For this reason it is possible . lay I25 remains energized after the momentary to utilize the grid bias in the tube to correct for detector actuation by a lock-in, circuit thru lead 70' errors in circuit constants of the condenser-resist I26, armature I21, contact I28 to relay I25. Con ance circuit and also to correct for variations in nection thru bank A is made in all positions ex different tubes. If, for instance, in the manu cept the side street green interval, and as bank facturing assembly, resistance 53 for timing the / A has bridging type wipers this circuit locks in 75 4 2,127,080 ‘ relay I25 until the side street ‘green position is reached where there is no connection on bank A to lead I29 and the relay is de-energized. In this way presence of trai’iic units on the side street is "remembered” until right of way is accorded to the side street. In an alternative circuit for locking-in relay I25, bank A is placed between terminal I32 and relay I25 and the other side of this relay connected directly to lead 5|. The wiper arms are now in position 5, since 10 the momentary current through the tube ‘I0 and relay 50 has caused magnet 05 to operate, ad--v vancing the wipers. It will be noted that posi tions 5 and 6 are also timed by charging current thru resistance 55. Grid bias is suitably adjusted by taps 65 on the resistor 40, wiper 45 on bank C. When the condenser has acquired su?icient voltage across its plates, tube ‘I0 becomes con ducting, and motor magnet 05 advances the wipers one step as described above. Positions 9 and I0 are the side street green periods. During these periods 9 and I0 connec tion is made on bank E of the line switch to energize relay 90 over lead 3|, relay 90, lead 5!, 10 bank E, wiper 40 to ground. Thus over arma ture 59, contact I00, lead IOI, armature I03, con tact I04, a circuit to illuminate the side street green unit II‘! is completed, replacing the side street red I I9. Through armature I01, contact to the condenser drawn through the same re sistance as period 4, and connections on the sev eral banks of the line switch are similar. If I06, lead I05, artery red unit H8 is illuminated. Timing vcondenser 50 will be charged through desired, a switch having fewer positions than the standard 25-contact type illustrated might be used, in which case these three positions 4, 5 and l'would be replaced by’ a single period timed resistance 50 in period 9 and through a similar resistance 5| in period I0. Each time the volt age on the condenser becomes great enough to 20 overcome the grid bias of tube ‘I0, the gas in the by a resistance three times the size of resistance 7 tube is ionized and the tube becomes conducting, 50. The total length of periods 4, 5 and 5 forms advancing the wipers of the line switch to their a minimum period of artery green serving to next position as disclosed above. Thus it is seen permit vehicles which may have stopped on the that under the condition pointed out, positions 25 artery during the preceding side street right of 9—I0 constitute a period of side street right of way period to accelerate and clear the intersec way of predetermined length. tion, and also to prevent too frequent interrup In period 9 there is »no connection on lock-in tion of artery right of way. bank A between lead I29 and wiper ‘44 and conAt the conclusion of each of these periods the sequently relay I25 is released in this period. 30 cathode-plate circuit of tube ‘I0 momentarily en ergizes relay 50 which enables motor magnet 05 Actuations occurring ‘in period S'also will not energize or lock-in relay I25, thus avoiding'un to advance the wipers in the manner aforede necessary wear on the relay. scribed. In period ‘I the control mechanism rests, in the absence of actuation of the side street re ‘ It is apparent that in near-continuous traffic, or in some instances under light tra?ic condi tions, a vehicle may arrive at the cross lane actu sponsive devices, and accordingly this period may atable device at the end of the green period in be called artery green rest position. The signal which case it may lose the right of way before changing relays 80 and 05 remain de-energized it has had suillcient time to cross the intersec maintaining the green light on the artery and tion. In period I0 the connection on bank A be 40 red on the side street. Accordingly in period ‘I I tween lead I29 and wiper 44 is again established, when relay I25 has not been locked in by actu in order that relay I25 may now vbe operated ation of a detecting device, the condenser charg and locked-in for the purpose of retaining the ing circuit from the positive end of the poten effect of actuations of such vehicles. The control tiometer 40, wiper 45, contact 5 on bank B, re apparatus therefore remains in such a condition sistance 54, to the ondenser is open between con that without further actuation right of way will tact I00 and arm ure I5I. However, upon the revert to the cross lane at the end’oi' artery mini event of an actuation of one of the detecting mum period. Since connection is made between devices, locking-in relay I25 in the manner afore the lock-in circuit I25 and ground over bank A brought out, the condenser charging circuit through resistance 54 is completed over contact Ill and armature I30; the condenser rapidly \reaches the voltage necessary for the plate cir cuit of the tube to become conducting, and the line switch wipers are notched from position 5 to position 5 by the energization and de-ener gization of the magnet 85. Obviously, from the above description, if a detector actuation has locked-in relay I25 before the wipers have moved into position ‘I', the condenser-charging circuit will not rest in its open position, but will be completed through armature I50, contact Ill ‘ and the resistance 54, thus causing the period to be terminated quickly. . In position 0 connection is made on bank F through wiper 49, lead 40, relay 95, lead 5| en ergizing relay 05. Relay 90 meanwhile continues tie-energized. Current now flows through leads II, 55, armature I01, contact I00, and armature 70 III, contact II2, artery yellow unit II4, while artery green unit I I5 is extinguished by breaking of the circuit through armature III and contact IIII. Side street red unit H9 remains energized as in thepreceding position. In period 8 the 15 timing is determined by charging the condenser and bridging type wiper 44 during all periods on from this side street memory period until the next succeeding first period of side street green, relay I25 once energized will remain locked-in until right of way is‘ granted for the waiting vehicle to cross; Period I0 is timed by the charging of condenser 58 through resistance 5| and upon the plate circuit'of tube ‘I0 becoming conducting, the wipers are advanced in the manner already de scribed to position I I on their respective banks. In position II, warning of impending changes in right of way is indicated, yellow or caution 'being displayed to the side street; red to the artery. Accordingly connection is open on bank ' F and made on bank E, so relay 95 is de-ener gized and relay 90 remains energized. Thus side street green is extinguished since armature I03 breaks circuit with contact I04 and engages con tact I02 completing circuit through side street yellow unit IIO. Artery red unit II5 remains illuminated by the circuit through armature I0‘I, contact I05. Charging circuit in this period is closed through resistance 52, lead 51. Condenser 50 will charge to the critical voltage of tube ‘I0, as determined by the amount of negative charge on grid ‘I2 from resistor 40, whereupon the motor 75 2,127,080 magnet 85 will be energized, causing the wiper arms to advance vto position I2. , By consulting the table of wiper contact posi— tions and signal indications above it will be noted that position I 2 in the second cycle of signal indi cations is the ?rst artery green minimum posi tion and corresponds to position 4 in the cycle just described. Thus the condition described at the beginning of ‘the signal indication cycle has 10 been reached and the condenser is charged again through resistance 53, as it was in position 4. Corresponding contacts on the line switch banks in cycles 2 and 3 are connected in parallel with those of cycle I, thus on each bank, contacts I2, 15 l3 and I4, and 28, 2I and 22 are wired in parallel with contacts 4, 5 and 5 ; contacts II and IS with contact 3, and so on. One contact, No. 23 herein, is an extra position on the line switch and although on the ‘light 20 banks E and F it may be connected to maintain the display of artery green and side street red of preceding periods 28, 2| and 22, on timing bank B a very low resistance 56 is placed in the con denser charging circuit. The condenser rapidly 25 reaches the critical potential of tube 10, when the notching operation will proceed again as described previously, rendering the duration of period 23 of insigni?cant length. Positions I5 and 24, artery green rest period, are similar to 80 position ‘I and may be timed through the same resistance as position 'I. The remaining positions of cycle 2 and cycle 3 correspond to those in cycle I as indicated in the above table. The ar rangement of signal indications for a particular 35 contact position is merely illustrative, and any desired arrangement di?erent from theembodi ment described might be used. , Under certain conditions it is sometimes desir able for a traf?c omcer to control the signal 40 changes manually. By turning switch 88 to the "manual” position the signal indicating means 5 and F to relays 95 and 90, red' is displayed to the artery and green to the side street. When the button I33 is again pressed, recti?er 88 is ener glzed from the transformer over leads I35, 30, switch 88, wiper 41, contact 8 on bank D, lead 89, contact 83, armature 82, leads 18 and 18. Con sequently upon energization of magnet 85, this circuit will be interrupted at armature 82, the wipers will be instantly advanced to position I0 in which the circuit to energize the magnet 85 is 10 again‘completed, and upon release of the button, the subsequent release of magnet 85 advances the wipers in the customary way, to position II. This signal indication of side yellow and artery red persists until the button I33 is again pressed. 16 Thus the rapid self-advancing circuit over arma ture 82 advances the wipers over all except one of a plurality of successive wiper contact positions where the same signal is displayed. An advantage of the present timing apparatus 20 lies in its automatic compensation in timing for variations in line voltage. Whenever the line voltage between leads 30, 3| increases, the termi nal output volts of the recti?er 32, 33 will also be increased, and the potential across the potenti-“ ometer 48 will be raised vaccordingly. For a given rise in line voltage the voltage between grounded lead 30 and taps ‘65 on the potentiometer 48 will be raised proportionally. A rise in .line voltage would tend to shorten the timing period because’ 30 of increased voltage applied across‘ the timing resistances to charge the condenser 58 to the ?ashover potential of tube 18. With the present circuit arrangement, however, 'the higher line ‘ voltage also increases the negative bias on the 35 grid of tube ‘I0 thereby raising the ?ashover. ' potential of the tube and compensates for the in creased condenser-charging rate. Corresponding compensation by automatically lowering the ?ashover voltage of the tube occurs when the line 40 This compensation will keep timing errors at a low value for sub ' voltage falls below'normal. will display a particular, indication until the but ton I33 is pushed whereupon the signal will stantial line voltage variations. change to the next set of indications in the signal It will be understood that the electrical timing cycle. This is accomplished by providing an au tomatic drive circuit for the line switch motor _apparatus embodying this invention may readily magnet, which-is interrupted in only one position be adapted to uses other than in the tra?'ic control system embodiment shown, and described of a plurality oi.’ successive wiper positions where herein. no change in the signal'indications is produced. From the foregoing it will bevseen that the 50 Pressing the button I33 energizes the motor mag net to advance the wipers to produce a change present invention provides electrical timing 50. in the signal. The duration of each signal is means for accurately timing periods whose dura \entirely in the control of the omcer, although the tion is adjustable at will, and said timing means system still proceeds through the same cycle of being so designed that variations in line voltage 65 colored signal indications. , When switch 58 is in the “manual” position, the normal circuit from lead 38 over leads I36, I38, to energize the primary of transformer 34 is inter rupted, and the timing circuit is de-energized. When switch 88 is in this position a circuit em bracing the recti?er 80 is completed over lead 19, contacts on bank D, wiper 41, switch 58, leads I35, I38, I35,secondary of transformer 34, recti?er 88. Assume, for example, that the wipers are en gaging contact #8 on their respective banks, in which case yellow will be displayed to the artery and red to the side street. When the omcer in charge pushes button I 33, circuit is completed from ground over leads 30, I36, I34 to energize the transformer. The latter in turn energizes recti?er 88 which causes line switch magnet 85 to pull in. Upon release of the button, the trans former, recti?er 80 and magnet 85 are deener gized, causing the line switch wipers to advance to position 8, where, by connections on banks E will be compensated for so that the accuracy of the timed periods will be maintained to a. high de gree in spite of these variations. It will also ap 55 pear that by means of the present, invention a tra?ic control system comprised of traffic actuat able control means, signalling means, and con trolling means composed essentially of a rotary 60 type step by step switch and a timing apparatus of the above character is provided ‘which will govern the passage of tra?ic through an intersec tion in an efficient manner for several different conditions described. 65 It will be understood that the above description and drawing is illustrative of but one embodiment of the invention and that variations in the con struction or changes in the arrangement of the parts may be made without departing from the 70 spirit of the invention as de?ned in the claims. We claim: 1. In a timing apparatus a rotary type switch having a plurality of positions and corresponding contacts closedvinv certain of the positions, an 75 2,127,080 . electro-magnet for advancing said switch from one position to the next in succession, a con said condenser between an initial value and a ?nal predetermined value over an interval of denser, means for charging said condenser over a period of time, a gas-?lled tube having a cath ode,'an anode and a grid, andswhich tube has a minimum voltage for conduction between the anode and cathode determined by the potential of the grid in respect to the cathode, a circuit including said anode and cathode and a relay, time, a gas ?lled tube having a cathode, an anode and a grid, a circuit including said anode and cathode and a relay and connected between the other terminal of said condenser and the power 10 said circuit paralleling said condenser whereby said circuit is rendered conducting by said tube when the voltage across said condenser has reached said minimum voltage for conduction, means operated by said relay to energize said ll electro-magnet, and means co-operating with some of said contacts to provide di?erent poten tials on said grid in di?erent positionsnof the ‘switch so as to adjust correspondingly the time periods in such positions. 2. In a timer the combination oi’ a switch hav ing a plurality of positions through which it is adapted to be operated cyclically and having cor responding contacts closed in one or more of such positions, a condenser, means including a source of energy and resistance for charging said con denser, means including contacts on said switch supply, said circuit being rendered conducting by said tube when the voltage across said con denser has reached said predetermined value and said predetermined value being controlled by the 10 potential of the grid in respect to the cathode, means operated by said relay to energize said electro-magnet,~ and means co-operating' with some of said contacts to provide different poten tials on said grid in different, positions of the 15 switch so as to adjust correspondingly the timev intervals in such positions. 4. In a timing apparatus a rotary type switch having a plurality of positions and corresponding contacts closed in certain of the positions, an 20 electro-magnet for advancing said switch from one ‘position to the next in succession, a condenser having one of its terminals connected to a power supply, means for varying the charge on said con to provide for independent adjustment of said denser between an initial value and a ?nal pre determined value over an interval of time, a gas ?lled tube having a cathode, an anode and a resistance in different switch positions, a gas dis charge tube having a cathode, an anode’ and. a grid, a circuit thru said cathode and anode in grid, a circuit including said anode and cathode and a relay and connected between the other terminal of said condenser and the power sup 30 cluding a relay and paralleling said condenser, said tube rendering said circuit conducting in response to a predetermined voltage across said condenser, means responsive to operation ot said 35 relay to advance the cyclic switch from one posi ply, said circuit being rendered conducting by said tube when the voltage across said condenser has reached said predetermined value and said predetermined value being controlled by the po tential of the grid in respect to the cathode, ‘ tion,to the next, and'means including certain of means operated by said relay to energize said said contacts for adjusting the grid bias of the discharge tube in different positions of the cyclic switch to vary the predetermined condenser volt age at which said responsive circuit becomes electro-magnet, a potentiometer, a plurality of tapping points on said potentiometer connected to a corresponding plurality of said contacts, and at least one additional contact connected to said grid and co-operable with said contacts one at conducting. 3. In a timing apparatus a rotary type switch having a plurality of positions and corresponding‘ a time to connect different potentials on said grid in diiferent positions of the switch so as to contacts closed in certain of the positions, an adjust correspondingly the time intervals in such electro-magnet for advancing said switch from positions. one position to the next in succession, a con denser having one of 'its terminals connected to a power supply, means for varying the charge on JOHN L. BARKER, HARRY A. WILCOX.