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Патент USA US2412571

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Dec. 17, 1946.
2,412,571
w? FEW
ELECTRONIC TIMING SYSTEM
Filed March 11, 1944
2 Sheets?Sheet 2
_
_
INVENTOR.
,/4/////am QM
BY
w/ ?
V
Patented Dec. 17, 1946
2,412,571
UNITED STATES PATENT OFFICE
2,412,571
ELECTRONIC TIMING SYSTEM
William Few, East Cleveland, Ohio, assignor to
The Clark Controller Company, Cleveland,
Ohio, a corporation of Ohio
1
Application March 11, 1944, Serial No. 526,046
5 Claims. (Cl. 250-27)
This invention relates to electronic timing sys
tems of the type in which, upon the closing of a
control circuit, a circuit to be controlled is ener
gized and after a timed period is automatically
de-energized.
The underlying principles of the invention may
be variously embodied, but the particular em
bodiments thereof chosen for illustrative purposes,
and described hereinafter, comprise the follow
ing. The winding of an electro-magnetic relay
is in the controlled or timed circuit, and this
circuit is connected to a ?rst set of anode and
cathode electronic space-discharge electrodes,
2
is maintained operated throughout the timed pe
riod referred to;
Figs. 2 and 3 are views each similar to Fig. 1,
illustrating different embodiments of the inven
tion in the use of which a control ccntactor may
be operated only momentarily to initiate the
timed period referred to;
Fig. 4 is a fragmentary view illustrating a
modi?cation of either of the embodiments of Figs.
1, 2 or 3, and in which tWo electronic tubes are
employed instead of a single tube as in Figs. 1, 2
and 3;
Figs. 5 and 6 are fragmentary views illustrat
under the control of a ?rst grid. A second anode
ing modi?cations which may be employed in
and cathode set of electrodes under the control 15 either of the embodiments of Figs. 1, 2 or 3;
of a second grid is also provided. The grids are
Fig. 7 is a View illustrating a different type of
normally energized at the polarity to prevent
current ?ow between their respective electrode
sets, the second grid being energized by a con
adjustment of an adjustable resistance shown in
Figs. 1, 3 and 4.
Referring to the drawings 1. have shown at l
denser normally kept charged. Upon closing a 20 a transformer having a primary 2 connected to
control circuit by a control contactor, the polar
alternating current supply mains 3 and 4 and
ity of the ?rst grid reverses, and discharge cur
having secondaries 5, 5, ?I, and 8. The derived
rent flows in the controlled circuit through the
voltages of the said secondaries may be variously
?rst anode and cathode set and operates the re
selected, but for illustrative purposes I have
lay; and the condenser discharges at a retarded 25 found suitable voltages to be 225 volts, 95 volts,
rate, thereby determining a time period during
25 volts, and 110 volts for the secondaries 5, 6,
which the inhibiting potential on the second grid
?l, and 8 respectively.
diminishes to a non-inhibiting value. At the end
At 9 is an electronic tube comprising two sets
of the time period the second anode and cathode
of electrodes, one set comprising an anode, cath
set pass discharge current, the flow of which cur 30 ode, and grid, at H), ll, !2, respectively; and
rent causes the polarity of the ?rst grid to again
the other set comprising an anode, cathode, and
reverse and stop the discharge current in the
grid, at l3, l4, [5, respectively.
controlled circuit. This causes the relay to return
I prefer to use a double tube of this type for
to the restored condition.
purposes of simplicity and economy. Such tubes
Thus upon closing the control ccntactor the 35 are available commercially, illustrative of which
relay operates, stays operated for a timed period,
is the commercial tube RCA 6AD7-G. This tube
and then restores.
is a high vacuum tube because of which the two
Contacts on the relay may be provided to con
sets of electrodes can function independently.
trol extraneous load circuits as will be under
At It is a condenser; a suitable capacity for
stood.
which may be 1A micro~farad; and at l1, l8, I9,
The primary object of the invention is to pro
28 are resistance units, the unit 20 being adjust
vide generally an improved timing system hav
able, and suitable values for these resistances be
ing the end results referred to above.
ing 1500 ohms, 250,000 ohms, one megohm, and
Another object is to provide a timing system
600,000 ohms respectively.
having the characteristics and mode of oper
At 2| is an electro-magnetic relay having a
ation referred to above and more fully described
winding
22, bridged by a condenser 23, and hav
hereinafter.
ing normally open control circuit contacts 24.
Other objects will be apparent to those skilled
The relay may have also any desired number of
in the art to which the invention appertains.
normally open or normally closed contacts to
The invention is fully disclosed in the follow 50 control other load circuits and illustrative of this
ing description taken in connection with the
I have shown at 25 normally open contacts con
accompanying drawings in which,
trolling the load circuit 23.
Fig. 1 is a diagrammatic view of a circuit and
The control switch or contactor referred to is
apparatus illustrating an embodiment of the in
shown at 21,.
vention, in the use of which a control ccntactor 55
?The various circuits and connections and other
2,412,571
3
rent ?ow between the anode l0 and cathode H
elements of the system not thus far described
starts, these electrodes being in a circuit compris
will now be described in connection with a de
ing the switch 21, the resistance unit I8, and the
scription of its operation as a whole.
secondaries ?I and 8; the derived potential in
Upon energization of the transformer second
aries by the primary 2, the 95 volt secondary 01 ducing this ?ow being the sum of the potentials
of the secondaries 1 and 8 or 135 volts.
6 charges the condenser � The charging cir
It will be observed that because of the high re
cuit comprises the resistance um't l'i?, wire 28, wire
sistance of the unit [8, the greater part of the
29, condenser 56, wire 39, grid 12, cathode H,
potential drop in the circuit of the electrodes ill
and wire 3|; the current ?owing between the grid
and cathode being that sometimes referred to as 10 and H is accounted for by the drop of potential
in the resistance unit 18. It follows that the
the grid current. The grid and cathode act in
secondary ?I is of little effect, and that the polarity
this respect as a recti?er and pass only alternate
of the wire 3'2 and the grid l5 will be negative
half waves of the derived alternating current,
(for positive values of the anode [3) as soon as
and the current is in the direction to charge the
the
recti?ed current flow between the anode and
condenser so that the plate of the condenser 15
cathode ill and H starts; and that this will cause
connected to the grid l2 by wire 38 is negative.
the grid IE to out off the ?ow between the anode
The condenser I6 is thus fully charged in the
l3 and cathode ill to de-energize the relay and
normal state of the system. The resistance units
allow it to restore.
19 and 20 across the condenser stabilize its charge
In operation therefore, the condenser i6 is
20
in a known manner.
charged by the secondary t; and maintains the
The potential across the anode IE! and cathode
grid l2 negative; and the grid i5 is maintained
II is the algebraic sum of the potentials of the
negative by the algebraic sum of the voltages of
secondaries 6, 1, and 8 or 40 volts but current flow
the secondaries 6 and ?1. Upon closing the control
is prevented by the negatively charged grid i2.
switch 21, the secondary 6 is neutralized, and
The grid [5 of the tube is also energized to be
the secondary l acting alone, changes the grid
negative (for positive values of the anode [3), it
�to positive, and the anode 13 and cathode it
being in a circuit comprising the secondary 6,
pass
current which operates the relay 2!. The
grid
15,
cathode
?wire 28, secondary 1, wire 32,
condenser It then discharges through the ad
.l4, and wire 3|, and the potential on the grid
being the algebraic sum of the voltages of the 30 justable resistance 26 and contacts 24 on the re
lay, and after a time period current flows between
secondaries 6 and ?i, or '70 volts, so that the grid
the anode It] and cathode I l, induced by the sece
I5 prevents flow of current between the anode
ondaries ?I and 8 and this current, ?owing through
l3 and cathode l4 notwithstanding that they have
the high resistance l8 changes the polarity of
the potential of the secondary 5 or 225 volts im
pressed thereon.
35 the grid I5 to negative, and the relay operating
current is thereby interrupted and the relay re
As will be observed, the winding 22 of the mag
stored.
netic relay is in the circuit of the anode l3 and
cathode M, the circuit comprising the secondary
5, wire 33, winding 22, wire 34, anode I3, cathode
Upon opening the switch 21, the condenser
again charges and renders the grid l2 negative
_ l4, and wire SI, and current flow in that circuit 40 and flow between the anode It and cathode H is
will operate the relay, but normally the relay re
mains unoperated or restored.
Upon closing the control switch 21 the sec
ondary 6 is in effect cut o? from the system, the
again cut oil and the system is ready for an
other operation.
_
,
It will be observed that in the above-described
operation of the system of Fig. 1, the control
switch 21 is maintained closed for the duration
of the timed interval, and this is desirable in cer
providing a high resistance by-pass for it. The
tain uses of the system. In some uses, however,
grid i5 is therefore then energized by the sec
it may be desirable to effect the initiation-of the
,ondary ?I alone, and the grid l5 now becomes posi
timed interval by only a momentary closure of
tive (for positive values of- the anode l3), and
current ?ows between the anode l3 and cathode 50 the switch 21, and to render this switch incapable
of interrupting the timed interval thus initiated
714 in the circuit above-described and operates
even if the switch be again operated before the
the relay 2!.
~
interval
has been completed. This type of con
This relay operating current being recti?ed by
trol of various classes of electrical apparatus by
the tube 9 and therefore flowing only on alternate
half waves, the condenser 23 is provided to main? 55 a manual switch is sometimes called ?non-beat?
control. Such a system is shown in Fig. 2.?.
tain energization of the winding 22 during the
i switch 21 and the resistance unit I?! and wire 3! ,
In this system, the relay 2|, besides having
the contact 24, has another contact 37 which is
closed when the relay operates; and this contact
(SU is connected by wire 38 to the wire 3|. By this
means, upon operation of the relay, theswitch 27
is bridged by, a circuit comprising the wire 36,
lowered-resistance discharge circuit for the con
contact 31, and wire 38.
denser H5 at the relay contacts 24, the circuit
Upon momentary closure of the switch 2?, and
being, from the condenser, by wire 30, through
upon the consequent operation of the relay 2!,
the adjustable resistance unit 20, by wire 35, con
this bridging circuit is closed and the switch 21
tacts 24, wire 36, wires 28 and 29 to the other
may then be opened and the system will go on
side of the condenser; the grid to cathode circuit,
operating as described for the system- of Fig. 1.
to maintain the grid [2 effective to prevent flow,
At theend of the timed period, when the relay
now'being through the switch 2?.
'
The condenser now discharges through the re- 7' 2i opens again and opens the contact 31, the
switch 21 being open, the condenser again charges
sistance unit 20 at a rate determined by the ad
other half waves in a well-known manner to hold
the relay continuously in operated condition.
When the secondary 6 was by-passed by the
control switch 21, the condenser it stopped
charging. When the relay operated, it closed a
justment of that unit.
At the end of a time
as before preparatory for another operation.
. . _
In the form of Fig. 3, a similar ?non-beat?
period during which the discharge goes on, the
manual operation is provided ,bya diiierent ar
negative potential on the grid 12 produced by the
condenser has'fallen to so low a value that our a rangement of contacts on therelay 2| which
5
2,412,571
makes possible the use of a smaller relay requiring
less power to operate it. An additional resistance
unit 39 is introduced bridging the wires 28 and
3|, a suitable ohmic value for which (when the
ohmic values of the other resistance units are
the same as those mentioned hereinbefore) is
15,000 ohms.
6
circuit including the relay winding 22 and the
anode and cathode i3 and H! of the tube, is that
of the sum of the secondaries 5 and 5, and that
therefore a larger more powerful relay may be
employed for the same size relay as before.
The adjustable resistor 29 is shown, in the ?g~
ures described above, by the conventional sym
On the relay 2!, besides the aforesaid contact
bol. In Fig. '7 it is shown more as it would be ar
24, which is normally open and is closed when the
ranged for adjustment in practice. The re
relay operates, a. contact 40 is provided which is 10 sistance 29 is in the two banks 43 and 4d. The
normally closed in the open position of the relay.
bank 43 is divided into ten sections l?i5?/35, each
The condenser 15 is normally maintained
with a tapped contact 46; and a movable contact
charged by the transformer secondary 5 through
ii? connected by a wire 48 to one end of the bank
the resistance unit ll, a wire Ill, the contact 43,
is movable to any contact. The bank 33 may
a wire 42, and thence by wire 28 to the condenser 15 therefore be cut in or out by tenths.
.
as before, the resistance unit 39 bridging this
The bank 5% has two sections rid-?159 of equal
charging circuit being of sui?ciently high ohmic
resistance, and the resistance of each equal to the
value as not to effectively by-pass the condenser
entire bank
and each section has a tapped
charging current and interfere with its charging.
contact 52. A movable contact
connected by
Upon closure of the control switch 27, the sec
a wire 53 to� one end or" the bank as can be moved
ondary 6 is by-passed through the resistance 61
to either of the contacts 52~52.
as before and charging of the condenser is in
By suitably positioning the movable contacts
terrup'ted and the relay 21 operates as described
on the tapped contacts of the two banks, the
before. The circuit for the secondary 1 through
value of the resistance 26 can be changed by
wire 32, grid 55, wire 3|, and back by wire 28 to
thirty steps; to correspondingly change the tim�
the secondary l, which keeps the grid l5 positive
ing eifected by the condenser H3.
to maintain the relay operated, now takes place
The invention is not limited to the exact de
through the resistance unit 39 so that the switch
tails illustrated and described. Changes and
21 may be opened after its momentary closure, or
modi?cations may be made within the spirit of
released and allowed to open, if, as would be 30 the invention without sacri?cing its advantages
customary, it is normally held open by a spring,
and within the scope of the appended claims.
like a push button.
The circuit from the condenser IE to the grid
l2 and to the anode ll, wire 3| and by wire 28
back to the other side of the condenser also takes
place through the resistance unit 39 to maintain
the grid l2 effective until the time interval has
passed. In other respects the operation is the
same as that of the other systems.
The con
denser !8 of course discharges as before through
the adjustable resistance 26, wire 35, contact 211,
and wire 42, and wire 28 as before.
As to the modi?cations of Figs. Q, 5, and 6, Fig.
4 illustrates the use of two tubes 9A and 9B in
stead of a single tube 9 as in the other ?gures,
the anode, cathode, and grid, [0, H, and 12 re
spectively being in the tube 9A; and the anode,
cathode, and grid, i3, i4, and !5 respectively be
ing in the other tube 93. The operation is the
same as that of the other ?gures.
As described above for Figs. 1, 2, and 3, a re
sistance unit i9 is used in connection with the
condenser l5 and discharge of the condenser is
initiated upon operation of the relay 2!, the dis
charge taking place through the relay contact :
24. This is the preferred arrangement particu
larly when the timed period is to be short. For
longer timed periods, the arrangement of Fig. 5
may be used. As shown the adjustable resistor,
This application is in part a continuation of
my copending application Serial No. 432,897,
February 28. 1942, for Electronic timing systems.
I claim:
1. In a timing arrangement, a source of alter
hating potential, a work circuit, an electronic an
ode and cathode in the work circuit subjected to
source derived potential, and a control grid there-
for normally negatively energized by a secondary
alternating potential derived from the alternating
source potential; timing means; a control con
tactor; a control contactor circuit; means includ
ing circuit connections rendered effective upon
closing of the contactor circuit to reverse the
polarity of the secondary alternating grid ener
gizing potential to immediately start ?ow of cur
rent in the work circuit, and to initiate the run
ning of a time interval by the timing means, and
again to reverse the polarity of the secondary
alternating grid energizing potential tostop ?ow
of current in the work circuit at the end of the
time interval, and maintain it stopped so long as
the contactor circuit is maintained closed.
2. In a timing arrangement; a source of poten
tial; a work circuit comprising an electronic
space-discharge path subjected to source-derived
potential; a grid normally negatively energized
by source derived potential and normally pre
here 28A, is simply connected across the con 60 venting current ?ow in the discharge path and
denser IS, the resistance unit 19 and ?the relay
work circuit; a control contactor; a normally
contact 24 being dispensed with. When charg
charged condenser; means rendered e?ective upon
ing of the condenser is stopped, the condenser
operation of the contactor to reverse the polarity
begins at once to discharge through the resistor
of the grid energizing potential to thereby start
20A. The successive timed periods with this ar
current flow in the Work circuit, and rendered
rangement may vary more than with the pre
effective to start retarded discharging of the con
ferred arrangement of Figs. 1, 2, and 3 but� when
denser; and means subject to condenser poten
the periods themselves are relatively long the
tial
and rendered e?ective by the reduction there
variation will be negligible.
of after a time interval of condenser discharging,
Again, in Figs. 1, 2, and 3, the resistance unit 70 to again reverse the polarity of the grid ener
l7 associated with the secondary 6 is connected in
gizing potential and stop the flow of current.
the line 28. Fig. 6 shows a modification in which
3. In a timing arrangement, a source of poten
it is connected in the line 3 I. With this position
tial; a work circuit comprising a ?rst electronic
of this resistance unit, it will be observed that, for
space-discharge path subjected to source-derived
example in Fig. l, the voltage impressed upon the 75 potential and controlled to normally prevent cur
2,412,571
7
rent ?ow therein by a ?rst grid normally ener
gized by source derived potential; a normally
charged condenser; a second electronic space-dis
charge path subjected to source-derived potential
and controlled to normally prevent current flow
therein by a second grid normally negatively en
ergized by the condenser; a control contactor;
circuit means rendered effective, upon operation
of the control contactor, to reverse the polarity of
8
being initiated by said source derived potential
upon discharging of the condenser for a prede
termined time period; controlling means?, respon
sive to current ?ow in the said second path, to
again reverse the polarity of the energizing po
tential of the ?rst grid to stop current ?ow in
the work circuit.
5. In a timing arrangement, a source of po
tential; a transformer energized from the source;
the energizing potential of the ?rst grid whereby 10 a work circuit to be controlled subjected to source
derived potential and comprising a ?rst electronic
current flow starts immediately in the ?rst dis
space-discharge path and a ?rst control grid
charge path and work circuit, and rendered ef
therefor; a second space-discharge path and-a
fective to start retarded discharge of the con
second control grid therefor; a ?rst, a second,
denser whereby current ?ow starts in the second
discharge path after a time interval of con 15 and a third transformer secondary?; connections
normally energizing the ?rst grid by the di?er
denser discharging; and means rendered e?ective
ential potential of the ?rst and second secondar
by current ?ow in the second discharge path to
ies to normally prevent current flow in the ?rst
again reverse the polarity of the energizing po
path and work circuit; a condenser; connec
tential of the ?rst grid to stop the current ?ow in
20 tions maintaining the condenser charged by po
the ?rst path and work circuit.
tential of the ?rst secondary and applying the
4. In a timing arrangement, a source of po
condenser potential to the second grid to nor
tential; a work circuit to be controlled subjected
mally prevent current flow in the second path;
to source-derived potential and comprising a ?rst
a control contactor; circuit connections rendered
electronic space-discharge path and a ?rst con
trol grid therefor; a second electronic space-dis 25 effective upon operation of the contactor to neu
tralize the said ?rst secondary and cause the said
charge path subjected to source-derived poten
second secondary to reverse the polarity of the
tial and a second control grid therefor; connec
energizing potential of the ?rst grid to cause cur
tions normally energizing the ?rst grid from
rent flow to start in the ?rst path and'work cir
source derived potential to prevent current from
?owing in the ?rst discharge path and work cir 30 cult, and to stop charging of the condenser, and
to start retarded discharge of the condenser; cur
cuit; a condenser; connections normally main
rent ?ow in the second path being initiated by
taining the condenser charged from source de
the sum of the potentials of the second and third
rived potential and applying the condenser po
secondaries after discharging of the condenser
tential to the second grid to normally prevent
current ?ow in the second discharge path; a con 35 for a predetermined time period; and resistance
in the second discharge path producing a drop of
trol contactor; circuit means rendered effective
responsive to operation of the contactor to inter
rupt charging of the condenser and to reverse
potential which e?ects reversal of the polarity
of the energizing potential of the ?rst grid and
thereby stops ?ow of current in the ?rst path and
the polarity of the energizing potential of the
?rst grid to start current flow in the work circuit, 40 work circuit.
WILLIAM FEW.
and to initiate retarded discharging of the con
denser; current ?ow in the second discharge path?
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