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Патент USA US2127080

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Aug. 16, 1938.
J. 1.. BARKER 5- AL
Filed Jan. 7, 1936
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BY Joan L. bAnksn AND Hmnv A. Wucox'i
Gan/M4,, mA57%
Patented Aug. 16, 1938
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
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
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.
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.
' 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
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
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.
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
Cycle 1 Cycle 2
Cycle 8 55
banks and wipers might be employed, and a line
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.
Artery yellow. - _ _
Side street room.
Side street green memory..-
Side street yellow ________________ ._
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
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
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
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.
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
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
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
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.
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
‘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
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
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
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.
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
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
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
changes manually. By turning switch 88 to the
"manual” position the signal indicating means
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.
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.
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
. 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
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
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
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