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Патент USA US2404739

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July 23, 1946.
Filed July 18, 1940
11 sheets-sheet 1
Robert 4E. Mumma
@LAL `v/
His Attorney _
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His Attorney
' Julyzs, 1946.
Filed July 18, 1940
11 Sheets-Sheet 5
Raben E. Mumma
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His Atturney
.July 23, 1946.
Filed July 18, 1940
11 sheets-sheet '4
Y Robert
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His Attom_ey_
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Filed July 1a, 1940
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11 sheets-sheet s.
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Rnbci-t E. Mumma
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His Attorney
Juìy 23, 1946. v
Filed July 18, 1940
ll Sheets-Sheet 6
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Robert E. Nîumma
His Attorney
July 23» 1946»
Filed July 18. 1940
11 She_etS-Shee‘l‘I 7
Robert E. Mumma
His Attorney
July 23„ 1946.
Filed July 18, 1940
11 sheets-sneu >s
Robert E. Mumma
His Attorney
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ll SheetséSheet 9
Robert E. Mumma
His Attorney
Filed July 18, 1940
1l Sheets-Sheet l0
WG. 10B
Robert E. Mumma
His Attorney
„my 2.3, 1946.
Filed` July 18, 1940
11 sheets-sheet 11
'342 204
Robert E. Mummà
By wlw.
His Att orney
Patented July 23, 1946
Robert E. Mumma, Dayton, Ohio, assigner to The
National Cash Register Company, Dayton,
Ohio, a corporation of Maryland
Application July 18, 1940, Serial No. 346,087
3 Claims.
(Cl. 315-323)
This invention relates to calculating machines
and more particularly relates to an electro-me
chanical calculating machine having a differen
tial actuator and an accumulator that function
solely by the ñow of electric energy Without me
chanical movement of the parts.
In such a machine, as herein fully disclosed and
as previously disclosed in the application for
United 'States Letters Patent ñled by Joseph R.
Desch and this applicant, Robert E. Mumina, on
March 20, 1940, and bearing Serial Number
325,040, selected numerical data is entered, by
Fig. 3 is a cross section through the key bank
y of Fig. 2 on the line 3--3.
Fig. 4 is a side elevation of the step-by-step
operating magnet for one denomination of the
indicator, the accumulator sensing means driven
thereby, and the indicator set in accordance
Fig. 5 is a section through part ofthe com
mutator and wiper arm assembly of the accumu- ’
lator sensing means shown in Fig. 4.
Fig. 6 is a wiring diagram of two denomina
tional orders of the diiïerential actuator.
Fig. 7 is a wiring diagram of an enlarged sec
means of an electronic differential actuator, into
tion of a portion of the units denomination of the
an accumulator comprising a plurality of denomi
nationally grouped electronic devices, the selec 15 differential actuator shown in Fig. 6.
Fig. 8 is a Wiring diagram of the main switch
tive operation of which devices during a plurality
and the manually-operated control circuits for
of data-entering operations causes the accumu
non-indicating, resetting, and restoring opera
lation of data.
The actuation of the accumulator by the díf
ferential is caused by electric impulses which is 20 Figs. 9A, 9B, and 9C, taken together, form a
wiring diagram of the units denomination of the
sue from the diñerential and which are received
by the accumulator.
An object of this invention is to provide, be
Figs. 10A, 10B, and 10C, taken together, form a,
tween such a differential actuator and its associ
wiring diagram of the tens denomination of the
ated accumulator, a relay for causing the dif
ferential impulses to be transformed into stronger
impulses of identical character as those delivered
from th'e differential actuator.
Another objectJ of the invention is to provide a
gas discharge electron tube between such a dif
ferential actuator andits associated accumulator,
the electric impulses issuing from the differential
General description
The machine embodying the invention may be
conveniently considered by sections which are
functionally comparable to the key banks, differ
ential actuator, accumulator, and visual indicator
of a purely mechanical `calculating machine.
actuator causing with each impulse a discharge
in ,the electron tube, whereby the changes of po
function, is shown diagrammatically in Fig. 1.
tential of an electrode of such tube may be uti
lized to actuate the accumulator.
Another object of the invention is to provide
circuits whereby such an electron -tube is self
extinguishing, so that it may be ñred rapidly in
response to each of a plurality of incoming sig
"With these and incidental objects in View, the
invention includes certain novel features of con
struction and combination of parts, the essential
elements of which are set forth in appended
claims and a preferred form or embodiment of
which is hereinafter described with' reference to
the drawings which accompany and form a part
of this specification.
Of said drawings:
Fig. 1 is a diagrammatic chart explanatory of
the functional relation between the several units
of the machine.
Fig. 2 is an elevation of a typical key bank,
` partly broken away.
The relation of these sections, `as regards their
The disclosed machine has a keyboard of two
denominations of nine keys each, representing
the units andthe tens denominational orders of
the decimal system of numbers. These key banks
may have set thereon any number from 1 to 99
_for entry into the machine in one operation.
The differential actuator having units and tens
denominational orders corresponding to the key
board, each of which denominational orders acts
under control of its associated key bank to enter
:1 data, into the accumulator, is purely electrical,
having no moving parts except for the key release
and the “single operation” control cooperating
therewith. The accumulator is purely an elec
trical device and has, in addition to the units and
tens denominational orders represented on the
keyboard, a hundreds or overflow denomination.
The accumulator includes a purely electric means
associated with each denominational order of the
>accumulator` for transferring carry-overs from
one denomination to the next 4higher denomina
tion. The visual indicator is set by an electro
mechanical sensing means for each denomination,
8, and 9. These tubes are arranged in a circuit
which means sense and are controlled by the
they may be ñred and rendered electrically con
ductive one at a time in sequence, one tube being
whereby, commencing with the starting tube,
data-representing electrical condition of the as
sociated denominational order of the accumula
fired by the conditions occurring during the start
tor. The principle embodied in the disclosure
ing of conduction in the next lower tube, which
can be expanded indefinitely ,in respect> to _the
lower tube itself is extinguished as the next tube
number of key bank controlled denominations
inthe series is rendered conductivel The start
and in respect to the number of overflow denomi
ing tube in a denominational series is fired by
nations and ‘their associated indicator units. 10 closing the starting switch le() (Figs. l and 6) to
The drawings disclose this sectional plan of con
commence the automatic sequential operation»`
struction of the machine. Certain controlsdeal
Thelfìring of the starting tube i'lres the “1” tube,
ing with special operations, the key release mech
and the firing of the “l” tube lires the “2” tube.
anism, and the sensing and the;indicatingdevices
The >firing of the “2” tube ñres the “3” tube and
are the only mechanically moving elements inthe
. extinguishes the “1” tube. This process continues
machine. While the drawings show only two de
until the tube representing the depressed key is
nominational orders in the keyboard and threein
reached, which tube, upon being ñrecl, cannot ñre
the accumulator and in the indicator, as many
the tube having the next higher digit value, as
additional denominational orders may be used as
the anode-energizing circuit of the tube having
20 the next higher digit value is broken by a switch
After the keys have been manually set and a
operated by the depressed key. The firing of
starting switch lili! (Figs. 1, 6, and 7,) has been
each Vtube in a denominational series, except the
closed, the data isentered into the accumulator
startingl tube, impresses an electric potential im
with a speed limited only by ordinary electrical
pulse upon an output conductor common to all
circuit characteristics, such as resistance, capac
- the digit-representing tubes of the denomination.
ity, inductance, and ionization time, and is not
There is one output conductor for each denomi
limited by the physical movement of anymcchan
national order of the actuator, and'each output
ical part. Data may Ice-entered into the accumu
conductor is connected to the corresponding de
lator many times faster than it takes to set up
nominational order of the accumulator, as indi
the data manually on `a keyboardv and'to closethe
cated by reference numbers i551 and |53 (Figs.
starting switch. An approximate time may be
1 and 6). The number of impulses impressed on
computed -for the entry of data into such an ac
each denominational output conductor in a given
cumulator if! the circuit characteristics are
operation is equal to the value of the depressed
known. In the circuit to be described, the circuit
key in that denomination.
element values are given‘as typical. In the par
The denominational groups of the differential
ticular embodiment based on these values, the
actuator are themselves operated sequentially, the
longest time required to enter data of' two de- « ñring of the tubes of the group in the units de
nominational digits, after closing the starting
switch, is approximately .0022 second, being the
time required` to enter the number “99,” which
is longer than the time required to enter the
nominational order being completed before the’`
firing of the tubes in the group in the tens de
nominational order commences, or Vice Versa, if
desired, as will be explained. Timing elements
have been provided in each group of tubes of the
It is within the purview of this invention to
diiîerential actuator, which elements are oper
use any of the well-known means for controlling
able, when the lower denominations are operated
the entry of data, other than the manual key 45 first in the sequence, to give a slight pause before
board described herein; for instance, the switch
the sequential firing of the next higher denomi
ing of the differential actuator circuits may be
national group of tubes commences, to permit de- .
controlled by any of thewell-known methods vfor
nominational carry-overs to be made to that de
sensing data suchV as that lrepresented on record
nomination of the accumulator without interfer
materials by perforations, light-controlling areas, 50 ence with the entry of the differential data. TheY
electrically-conductive areas, or magnetized
' electric potential impulses, as they occur in the .
areas. The key bank-control is used in lthis em
respective output conductors from the differen
' number “10.”
bodiment as one example of differential circuit
tial, actuate their` respective accumulator orders,
The electro-mechanical sensing and indicating 55 each impulse being so timed asv to be received by
the accumulator before the next impulse is pro
means is constantly ready to ’indicate new totals
switching means.
as new data is entered and is relatively slow in
operating compared with thetime taken tomake
an entry of data into the accumulator, yet it will
follow the operation of thefaccumulator and ulti
mately indicate the amount finally stored in the
accumulator, as it is not positively connected to
the accumulator, but merely explores its electri
The accumulator consists of the three denomi
national orders, units, tens, and hundreds. Each
denominational order of the accumulator con
sists of ten tubes representing the digits 0, l, 2,
3», 4, 5, 6, '7, 8, and 9, which are arranged in a
circuit so that they are ñred one at a time in
endless chain sequence, either by the impulses
the accumulator is sensed, and then stops. If the 65 sent through the output conductor of its asso
ciated diiîerential actuator or by impulses pro
amount changes, the exploring commences
duced by the transfer device, with the exception
again. The indicator is mechanically attached
of _the overflow denomination, which is actuated
toand shows the position-of the exploring means
only by the impulses from the transfer device kof
at any time.
' i
The diñerentia-l actuator (Figs, ' 1 and V5) is 70 the next lower denominational order. .The carry
cal condition until the- amount Aiinally stored in `
composed of aigroup of ten grid-controlled gas
eous electron» discharge tubes for each denomina,
tional order. The ten tubes in each denomina
tional order consist of a “starting” tube Aand nine
overs from one denomination to the other are
made by having an extra electric impulse in
troduced in the next higher denominational order
upon the entry of an impulse in the «lower order
tubes representing the nine digits l, 2, 3, 4, 5, 6, 7, 75 after any “9” digit-representing tube has .been
fired in that lower order, said impulse in the
lower order also having its regular function of
firing the “0” or zero tube in the lower order.
If the main supply of electric current be
switched off by main switch 99 (Figs. 1 and 8),
deenergizing the accumulator and the sensing
Inasmuch as the denominational groups of tubes
means before resetting the accumulator to zero,
of the differential actuator are fired in sequence,
the indicator Will still have set thereon the last
the accumulator orders are added into in the
amount in the accumulator. The accumulator
same sequence. In the circuits as disclosed, the
electron tubes, being deprived of current, will
pause between operations of the different groups
have no tube conductive and therefore will have
of tubes of the actuator is provided for the pur
no data therein. Under these conditions, in the '
pose of allowing the denominational carry-over 10 event the main supply of current is again turned
impulse, if any, to actuate the next denomina
on by closing switch 90, the accumulator is caused,
tion of the accumulator before impulses from
by the dow of energy through the wiper arms,
the differential actuate it, Such interference be
to render the proper tubes conductive in ac
tween carry-over impulses and differential irn
cord with the data on the indicator. This re
pulses may be rendered impossible by entering
storing of data into the accumulator is accom
the data into the higher denominational order be
fore entering it into the next lower denomina
tional order, which is done by arranging for the
highest order of the diiîerential actuator to be
operated ñrst. This may be accomplished by
renumbering the units keys (Fig. l) as tens keys
(Fig, 11) and renumbering the tens keys as units
keys and having output conductor |50 lead to
the tens bank input terminal of the accumula
rtor ‘and having the conductor |53 lead to the
units bank input terminal of the accumulator.
The accumulator, after having data entered
therein, has one tube in each denomination re
maining in a conductive state, said tube repre
senting the units digit corresponding to the ac
cumulated data of that denomination.
plished automatically, as will be explained.
A non-indicate key switch 423 (Figs. l and 8)
has been provided so that the accumulator may
be operated without the indicator functioning.
If the switch 423 is closed after data-entering
operations, the indicator will be set in accordance
with the accumulated data.
The action of the grid-controlled gaseous dis
charge electron tubes used in the differential ac
tuator and accumulator is well known. An elec
tric potential of suii'icient magnitude impressed
between a cathode and an anode in a gas-filled
envelope is controlled by an intervening grid
element which is normally provided with a nega
30 -tive bias potential with relation to the cathode
so as to prevent the flow of electrons to the
sequent entries of data into a denomination cause
a continuation of the sequential chain firing of
the tubes, beginning with the tube having the
next higher digit value to the conductive tube. 03
Thus, the accumulator differsfrom the actua
tor, which has no tube conductive between data-`
entering operations. The iiring of the tubes in
the diiîerential actuator is self-timed, whereas
the' firing of the tubes in the accumulator is 40
timedrby the impulses from the differential actu
A sensing means is provided for each denomi
national order of the accumulator, the “zero”
tube in each denominational order of the ac
cumulator being especially provided to be sensed
in case no other tube of the denomination is con
ductive, making it possible to sense the zero or
cleared condition of a denomination in a posi
tive manner.
The normally operative sensing
means of each denomination explores the condi
tion of the accumulator tubes through electri
cally-connected contacts, one by one, until a con
ductive tube is located, whereupon the opera
tion of the' sensing means is made to cease and
the number which that tube represents is there
by made visible by a number wheel set in accord
ance with the position of the then stationary
sensing means. The sensing means has explor
ing or wiper arms representing a denomination,
which arms are always conditioned to .move over
the sensing contacts until a conductive tube is
sensed in the particular denomination. If the
' wiper arm is stationary on the contact related to
a conductive tube and the tube is extinguished byV
the entry of data into the accumulator, the ex
ploring movement of the wiper arm will com
mence and continue until the new contact rep
If the biasing grid potential is reduced
to a point 'Where it is no longer in control of the
emission of electrons from the cathode, current
will now at once through the tube from the
Ácatho-de to the anode and in so doing will ionize
the inert gas within the tube. The ionization oi
the gas within the tube causes an increase in
the fiow of electrons- from the cathode to the
anode and renders the grid incapable of further
blocking the electric flow. This ñow, once
started, will continue even though the grid be
restored to its normal bias potential and will not
cease until the Vcathode-anode current is inter
" rupted by some other means. When the gas in
the tube is ionized
the electron ñow has
started, the tube is said to have been fired, or
rendered conductive. The conductive tube may
be extinguished, or rendered non-conductive,
d. either by adjusting the cathode capacity and re
sistance so that for an instant, as the capacitors
are charging, there is no now of current from
the cathode, or by shutting oli the potential
completely. Under these conditions the grid, if
at normal bias potential, resumes control. Both
of these phenomena are used in the disclosed
machine, as will be explained. Ordinarily the
bias potential of the grid with relation to the
cathode is not kept at a. hair-trigger point, but
at a substantial bias, thus rendering the tube
more stable and unresponsive to slight fluctua
tions oi potential of the grid.
The automatic sequential firing of the tubes
in the differential actuator is accomplished by
piacing a high resistance in the cathode supply
circuit, which causes an abrupt positive rise in
potential of the cathode of a tube as it fires,
and this abrupt rise in potential is utilized to
resenting the new accumulation is found.
extinguish the tube of next lower digit `value in
'I'he accumulator is cleared or set to Zero by 70 the series by temporarily raising its cathode _po
extinguishing all the tubes and subsequently
tential above the potential of the anode, and,
firing the zero tubes in each denomination. The
by the same positive potential rise, to destroy
sensing means then resume their exploring oper
the grid control of the tube having the next
ation and stop at zero in each denomination, be
higher digit value, causing it to iire unless it be
cause those tubes are now conductive.
` cut out by switch means operated by the keys.
' In the accumulator, the same phenomenon
the rise in potential 4of the cathode when the
tube iires, caused by placing a high resistance
The keyboard
The keyboard consists of a units denominationl
key bank 6| (Fig. 1) having nine digit keys 62‘
in the cathode supply-is used to extinguish the
tube having the next lower digit value in the
series, as is the case with the dilîerential actua
tor, and to weaken the grid control of the tube
having the next higher digit value by reducing
key bank 63 having nine digit keys 86 (Figs. 1
' its bias to the trigger point, so that the next
one bank will be suflicient for an understanding
(Figs. 1, »2, >3, and 6) and a tens denomination
and 6). The keys in each bank are of similar
construction, and a description of the keys in
potential impulse from the differential actuator,
of all the keys.
which impulses are common to all the tubes of
the accumulator, will cause only the tube with
the weakened grid bias to fire. More detailed
explanation will be given on this' subject as the
accumulator is described more particularly,
Each key hasv a stem 66 (Figs. 2 and 3) _slidably mounted in alined holes in a top plate 64;
and a bottom plate 65 of a unitary key bank,
said plates being spaced and’fastened together
by transverse vertical websl'i3 and '14 (Fig. 2),
Thedigit keys, by operating switches, control
the stopping of the ñring of the tubes in each
of 'the differential groups after predetermined
each of which has laterally projecting ears 61
numbers or” tubes> have been ñred. As each tube
is fired, it produces, by the rise in its cathode
with a restoring spring 10 (Fig. 2), which en
gages the bottom plate 65 andis contained Yin a
slot -|| in the key stem, where it is retained by
projections l2. Asa key is depressed, the spring
compresses against the bottom plate 65, giving
the key an upward restoring urge. The keys are
, potential, an electric impulse in a conductor
common to all the differential actuator tubes in
the denomination, which impulse is conveyed to
the ' corresponding order of the accumulator,
which causes the firing of the tube next in nu
merical order. Thus, except for the release of
the keys after the entry of data and except for
the Ymeans to prevent a repeat entry while the
keys are still depressed, there are no movements
of mass involved in data-entering operations eX
to engage side plate members 68 and 69 (see also
Fig. 3) of the key bank. Each key is provided
» limited in their upward motion by a shoulder on
the key stem 66 striking the top plate 64. A key
locking plate 'l5 (Figs. 2 and 3), having celar
ance holes 'I6 for each key stem, is slidably
mounted in clearance holes in the Webs 13 and'l4.
30 The locking plate 15 is urged to the left, as shown.
cept the mass of electrons and ions causing the
in Fig. 2, by spring 11 until the edges of thekey
electric current. The only factors which limit
the speed of the entry of data are electrical in
clearance slots contact the key stems. As a key
is depressed, the locking plate is forcedïto the
right by a camming surface on the key stem
nature and are placed in the circuit for the
proper timing of the impulses andtheir actuated 35 until notch 18 allowsthe locking plate to move
to the left, locking the key in depressed position.
By chamfering each of the notch edges, the -ac-vv
Thelspeed of the actual entry of data into the
tion of the key bank is made flexible, causing any
accumulator is so extremely rapid that the time
of making such an entry is negligible in com
depressed keys in the bank to be restored when
parison with the duration of the manual move 40 another key in the bank is depressed. Each key
ments necessary to press the starting key. The
stem has inserted therein an insulating web
formed of two pieces 19 and 86 (Fig. 3) having
time lapse between the pressing of the starting
button and the consequent firing of the tubes in
ears projecting into slots in the key stems 66
and into guiding slots 8| in the side plate mem-`
the differential actuator and the accumulator
may be as short as .001 second for the entry of 45 bers 68 and 69, so that the insulating-Web pieces'
a single digit. From this it will be apparent that
slide up and down with the keys. On each web
the speed of making an entry into theaccumu
are four contacts 82, 83, 84, and 85 (Figs‘ 2 and
lator is extremely fast in comparison to> the
3), each of which contacts in the up position can
speed with which the data may be set up either
close a circuit between one pair of switch points
bymanual keys as shown in this embodiment or
and in the down position can close a circuit be
by other more rapid data-entry control means
tween another pair of switch points. These
such as mechanically-sensed, electrically-sensed,
switch points are supported by the side plate
or light-sensed records, which data-entry con
members 68 and 69. Therefore, by the depres
trol means have been mentioned as within the 55 sion of a key, four circuits may be .broken and
purview of the disclosure.
four circuits may be closed. The invention uses
The diagrammatic representation shown in
but three of Vthese four available switches, the
Fig. l illmtrates the denominational groups in
description of this key bank being given to illus!
trate one way in which multiple switching may
the diiîîerential actuator, the accumulator, and
the indicator, These groups may be added to as 60 be accomplished by a single key. A key release
solenoid 26| for the units bank of keys (Figs. 2
desired. There may be more than one overflow
and 6), when energized, moves lever 263 coun
denomination, if desired, but there must be one
accumulator order for each denomination of the
ter-clockwise, around pin 264, to move the lock
ing plate 15 to the right and release a depressed
diilerential actuator and one indicator for each
denomination of the accumulator.
65 key. A similar` solenoid 262 causes the release of
any depressed key in the tens bank of keys.
The principle of the invention yfor this dis
rl‘here is one gas-filled electron tube |55 (Fig.
closure is embodied in a machine having cer
tain electric supply potentials and electronic de
6) for controlling theoperation of both solenoids
vices of certain electrical characteristics. In bal
26| and 262'. The controltube |55, when ñred,
ancing the circuits, adjusted resistors and ca 70 energizes a solenoid |49 to close the normally
pacitors are used. Electronic devices or poten
open switch |41, which supplies the> grounded
tials ,of dilïerent characteristics may be used
solenoids v26| and 262 with 45 volts positive po
without departing from the principle disclosed
tential, causing these solenoids to becomeener
by this invention, merely by using different val
gized and operate their armatures and thus re
ues of resistance and capacity.
75 lease any depressed digit keys.
The circuits entering into the operation of the
ductive until its plate circuit is interrupted by'
control tube |55 will now be considered.
As the main switch 90 (Figs. 1 and 8) is closed,
this tube remains conductive, it is impossible to
opening switch |00 or switch |46, and as long as
terminals 9|, 92, 93, and -94 are impressed with
the following electrical potentials: 1'10 volts pos
itive, 45 volts positive, 6.3 volts positive, and 150
volts negative.
start the sending of a second group of impulses
over output conductor |50. After the ensuing
in these figures.
the keys. The 'starting switch |00 must be held
sequential firing of the “1," “2,” “3,” “4,” and “5”
tubes oí the units bank, and the starting tube
Terminal 93, which has a potential of 6.3 volts
and the-“10,” “20,” “30,”> “40,” “50,” “60,” and
positive at this time, supplies the current to heat
“70” tubes of the tens bank, a positive cathode
the cathode 265 of control tube |55 and is shown 10 potential impulse caused by ñring the‘f'lO” tube
grounded in Figs. 6 and ’1 through a typical heat
is switched onto the firing impulse conductor |52
er ñlament symbolical of the heater ñlaments of
by the key-operated switch |6| to fire the con
all the tubes. The heater circuits from the` ter
trol tube |55, which tube causes the energization
minal 93 to the tubes have been omitted be
of ‘the solenoid |49 and thereby the energization
cause they would tend to obscure other circuits 15 of solenoids 26| and 262 to cause the release of
When the main switch =90 is closed and termi
closed until solenoid |49 is energized. When the
nal 94 has a 150-volt negative potential applied
solenoid |49 is energized, switch |46 is operated
thereto, the conductor 95 assumes this poten
to disconnect the ñring impulse conductor |52
tial. Grid 261 of the control tube |55, when no 20 and conductor |44, which supplies plate potential
digit keys have been depressed, assumes a nor
to the tubes of the diiîerential actuator, from the
mal bias of 150 volts negative by being connected
source of potential to which they have been con
to the 150-volt negative conductor through resis
nected by the closing of the starting switch |00.
tor 268 of 250,000 ohms and the paralleled resis
By thus removing the potential from the plates
tor and capacitor comprising resistor v |58 of 25 of the tubes any conductivetube will be extin
100,000 ohms and capacitor 620 of .005 micro
guished and none of the tubes can be rendered
conductive, so that any impulses which would be
The cathode 265 of the control tube |55 is con
generated by shifting contacts as |04, |43, | 5|,
nected to ground. With the grid 261 at a po
|6I, and |9|, when the keys are restored to un
tential of 150 volts negative and the cathode 265 30 depressed position with the starting switch |00
grounded, the tube |55 will not ñre.
closed, would not cause a misoperation of the
When the main switch 00 is closed, the 170
volt- potential of terminal 9i will not be applied
When the “70” key is depressed, as described
directly to the plate 266 oi the control tube |55.
above and shown in Fig. 6, switch |6| connects
However, when the starting switch |00 is closed, 35 the point 212 and the ñring impulse conductor
the plate 266 has 170 volts applied thereto
|52 to ground through the resistor 269 of 100,000
through a circuit which extends from the termi
ohms, the resistor 210 of 25,000 ohms in parallel
nal 9|, over closed contacts of the starting switch
with a capacitor 213 of .02 microfarad having in
|00, through resistor |48 of 300 ohms and the
series therewith a resistor 900 of 2,500 ohms,
solenoid |49. To slow down the application of
through the tens denominationloutput conductor
this potential to 'the plate ~and prevent the possi
§53 and the resistor 21| of 5,000 ohms. This
ble ñring of the tube by the sudden application
causes the potential of the point 212-and grid 261,
of this potential when the starting switch is
which are connected to the 150-voltV negative
closed, a grounded capacitor 28| of .1 microfarad
conductor 95 through the resistor |58 of 100,000
is connected to the plate circuit at a point be
ohms and capacitor 620 of .005 microfarad in par
tween the resistor |48 and the solenoid |49.
allel, to drop from 150 Volts negative to approxi
When no digit key has been depressed, the
mately 84 volts negative, which drop is not suñ‘l
closing of switch |00 after switch 90 has been
cient to cause the tube to ñre or be conductive.
closed, in addition to supplying the plate poten
If the circuit just traced were the only circuit in
tial to tube |55, also supplies a positive potential 50. the tens bank, the point 212 would assume the
to its grid 261 through switch |46, resistor |0| of
potential of about 84 volts negative, but circuits
200 ohms, and resistor |02 of 100,000 ohms,
associated with the “10,” “20," “30,” “40,” “50,”
through the closed contacts as |03, |04, through
“60," and “80” tubes are also included in the tens
the iiring impulse conductor |52, and resistor
bank. These circuits form parallel paths which
266. This 1'10-volt positive impulse on the grid
l extend from the 150 volts negative conductor 95
261 changes the potential of the grid from nega
through resistors 038, 613, 648, 653, 660, 56|, and
tive to positive and causes the tube |55 to fire and
61|, throughiswitches similar to |6|, through re
become conductive, the current flowing through
sistors similar to 269, through resistors and ca
the tube and plate circuit energizing solenoid |49,
pacitors in parallel similar to 210, 213, and 900,
which operates and closes the circuit to key re (il) to the tens denominational output conductor |53
lease solenoids 26| and 262, as explained above,
and thence through resistor 21| to ground. These
without any result as far as the digit keys are
parallel paths between the 150-volt negative con
conçerned, as none were depressed.
explained, to start the sequential ñring of the
ductor 95 and the output conductor |531 cause
the effective resistance of this part of the circuit
to become smaller and raise the negative poten
tial of the tens output conductor |53 and also
raise the negative potential` of the point 212
slightly above the 84 volts negative mentioned
above. This raise in potential of point 212 will
not affect the operation of the' tube |55. When
the tube lm10” fires, itscathode will acquire a
positive potential which will cause the potential
of the iiring impulse conductor |52 and point 212
to change so that the potential of the grid 261
tubes in the units bank. . Tube |09 remains com.
`Will become about ,2l/2 volts positive and will
However, if keys have been depressed-for ex
ample, the “5” key in the units bank and theY l
“70” key in' the tens bank-the 170-volt impulse
introduced on conductor |52, by closing start
ing switch |00 after the main switch 90 hasv
been closed, does not directly affect the grid 251,
but is switched so that the 170 volts positive im
pulse is impressed on the grid of-the starting tube
|09 of the units denomination, through resistor.
H5 of 400,000 ohms, ñringthat tube, as will be
The conditions resultingV from the firing ofthe
cause the ,tube |55 to lire and become conduc
starting tube |00 are such that they have no effect
tive. VThe manner in which the potential of the
on the digit-representing tubes exceptto fire tube
cathode of tube “70” is raised to a positive value
|2| representing the digit “1.” The method of
to change the potential of the grid 261 from neg
ative kto positive will be made clear during the CII firing the “l” tube by a starting tube toy com
menoe the differential action is used as a' con
description of the operation of the differential ac
venient way of impressing a uniform firing im
tuator. The iiring of tube | 55 will result also if a
pulse Von the grid of the “l” digit-representing
key in the units denomination bank is depressed
tube |2|, in operations wherein a key of that de
and no key in the'tens denomination bank is de
pressed, as the impulse from the last tube to nre 10 nomination is depressed. It is to `be noted» that
the starting tube could be replaced by any other
in the units bank will have its cathode positive
potential impulse shunted around the tens bank ‘ means .that would ñre the “l”A digit-representing
tube. The sequential firing of the tubes is so rapid
on conductor |52 to the grid 261 of the key re
that the firing of the “l” digit-representing tube
lease control tube |55 instead of to the starting
cannot be done reliably by the switch |00"a,l_one,
tube |54 of the tens bank, by reason of all the key
because of the possibility that the operator might
switches in the tens bank being in normal posi
vibrate switch |00 in closing it, thus giving more
Dz‘ß’erentz'al actuator
In describing the differential actuator, as re
gards its electrical operation, it is necessary to
trace the flow of electric energy through the cir
cuits. As the operation of the diiîerential ac
tuator is dependent on relative values of the elec
tric potentials, resistors, capacitors, and the elec
tron tube constants, for the timing and the se
quence necessary in producing the differential ac
tion, actual values will be given as an example.
These values are given to show how the differ
ential operates and should not be considered the
only set of values which can be used. The values
used are determined by the input voltages select
ed, by the type of electron tube selected, and by
the speed of operation needed. It should be
evident from the explanation which follows that
than one ñring impulse to> the digit-representing
tube |2| before the keys are released and caus
ing the firing of the selected tubes: more than
once, Which would result in an error in the entry
of data. The starting tube is not extinguished
and therefore cannot be fired-again until the
data-entering operation is completed and all the
tubes are deprived of energy by the opening of
switch |45.
It will be explained later how the
digit tubes are extinguished after firing, either
by the action of the next tube firing or by the
completion of the data-entering operation caus
ing switch |46 to open.
Each of the digit-representing tubes I2 |> andV
|20 has associated therewith the circuit which
connects the 15G-Volt negative conductor 95 to
the ground. The circuit for the “l” digit-repre
senting tube is representative and is traced as
follows from ground: through resistor |26 of
5,000 ohms to point |24 and output conductor
|50, through resistor |25 of 25,000 ohms and ca
pacitor |35 of .02 microfarad and resistor 90|
put conductors |50 kand |53 to the accumulator,
of 2,500 >ohms in series with the capacitor, in>
y as has been said, in about .0022 second after the 40 parallel to point |23, through resistor |30 of
starting switch |00 (Figs. 1 and 6) is closed, and
100,000 ohms, through switch |60` of the unop
the number “l” may be impressed on the output
erated digit key to point |29- and through- re
conductor |50 to the accumulator in about .0003
sistor |`3| of 100,000 ohms, to the 15o-volt nega
second. If there were ñve denominational key
tive conductor 95. The cathode for the “l” digit
banks, the number “99999” could be impressed 45 representing tube |`2| is connected in this circuit
upon the five output conductors to the accumu
at point |23, and the grid for the “2” digit-repre
lator in about .0058 second. Inasmuch as it is
senting tube |28 is connected, through resistor | 5l>
necessary for the accumulator to respond to the
of 500,000 ohms, to the point |29. The connec
impulses from a given denominationV of the dif
tion of the cathode of the Vtube of lower digit value
ferential actuator one by one, it is apparent that 50 to the grid of the tube of next higher digit value
its speed of response is at least fractionally faster
by means of circuits such as this one enables
than the actuator. The extremely high-speed
the firing of one tube to cause the next tube to
production of differential impulses and operation
ñre in sequence.
of an accumulator by the impulses are due to the
Although but two digit-representing tubes are
fact that they are accomplished solely by the 55 to‘be considered, the explanation given Will serve
flow of electric current without movement ofV
for the whole denominational‘bank of nine tubes,
ponderable mass.
as the resistors, capacitors, and bias potentials
The wiring of the circuits of a two-denomina
used are of the same values.V The firing of the
tion differential actuator is shown in Fig. 6. An
tubes‘occurs in so short a period of time, ranging
enlarged section of part of the circuit is shown 60 in the ten-thousandths of a second, that the
in Fig. 7, to which reference is principally made
transient changes in voltage cannot be measured
in the following explanation.
with absolute certainty, and therefore, although
In giving the explanation of operation of the
the use of the resistors, capacitors, and the po
sequential firing of the tubes in the differential
tentials of the electric supply lines of the values
actuator, the first portion of the units bank (Fig.
as given will result in >accurate operation of the
'7) is used as an example. This portion shows
machine, the potential ñuctuations in the circuits
starting switch |00, the “l” and “2” digit keys
as> stated should be deemed approximations andk
02,> the tubes |2| and |28 representing digits
are given chieñy to explain the theory of opera
“1” and “2” respectively, the units denomina
tional order starting tube |00 for starting dif
In the explanation of the operation of the dif
ferential operation of the digit tubes when a key
ferential actuator as made in connection with
is depressed in this order, the key. release con-v
Fig. '7, it Vwill be assumed that the “2" digit key
trol circuits, the circuit breaker switch for “sin
E2 has been depressed manually from a position
gle operation” control, and the various circuits
shown by the full lines to the position shown by
coordinating these elements.
75 the dotted lines and the switches |04, |43, andy
certain of the time factors involved result from
the proper choice of these values. With the val
ues given here as an example, the impulses for
the number “99” may be impressed on the out
|5| have been moved from the full-line position
to the dotted-line position.
As mentioned previously, when the main switch
90 (Figs. 1 and 8) is closed, terminals 9|, 92, 93,
and 94 are impressed with the following elec
tric potentials, respectively: 170 volts positive,
45 volts positive, 6.3 volts positive, and 150 volts
negative. These terminals, also shown in Figs.
the starting tube |09 to the 170-volt positive
terminal through the circuit over the closed
switch |00, over the normally closed switch |40,
and resistor |0|, and from this point over con
ductor |44, capacitor ||2 of .005 microfarad in
‘ parallel with resistor ||3 of 400,000 ohms, to
plate |10.
As the starting tube fires, it allows current to
6 and ‘7, supply the necessary electric energy to
now from the cathode |08 to the plate ||0. The
operate the differential actuator.
10 now of current from cathode |08 to plate ||0 is
Terminal 93 of 6.3 volts positive, as has been
not limited by the ¿100,000-ohm high resistance
mentioned, supplies the current to heat the cath
| i3 until capacitor | |2 becomes charged, at which
odes of all the electron tubes in the differential
time the resistor` |ê3 becomes effective to reduce
actuator and accumulator and is shown ground
the plate-cathode current and also reduce the
ed in Figs. 6 and '1 through a typical heater fila
potential of cathode |08. The potential drop
ment symbolical of the ñlaments of all the tubes.
across the tube |09, when conductive, is about 15
The heater circuits from the terminal to the vari
volts, as is usual in gaseous electron tubes of this
ous tubes have been omitted for the reason that
type. This makes point | I4 have, after the firing
they would tend to obscure the other circuits to
of tube |09 and as capacitor ||2 starts to charge,
a potential of about 155 volts positive with re
spect to ground` When resistor ||3 assumes the
current load as the 'capacitor | l2 becomes
be described.
Heater elements, which have been -
symbolically shown in each tube, are connected
to terminal 93 and become heated when the main
switch 90 is operated.
When the main switch 90 is closed and the po
tential of 150 volts negative is applied to con
ductor 95, the grid of the starting tube |09, which
charged, thepotential of the plate ||0 drops to
about 25 volts positive with respect to ground,
and the cathode |08 and point ||4 assume a po
tential of about 10 volts positive with respect to
is connected to this conductor through resistor
ground. After the ñrst surge of current from
|05 of 100,000 ohms and capacitor I|| of .005
cathode |08 to plate ||0 in tube |09, the resistor
microfarad in parallel, point |06, and resistor ||5
| I0 maires the current flow very small. Resistor
of 400,000 ohms will assume a nega-tive poten 30 l i0 limits the cathode current dow before resist
tial of approximately 150 volts. At the Sametime,
ance ||3 takes effect and acts to make the po
the potential of the cathode |08 of the starting
tential of cathode |08 high while capacitor ||2 is
tube |09 and the point ||4, which are connected
charging. Resistor |05, of 100,000 ohms, andre
to ground through resistor ||0 of 25,000 ohms,
sistor | |5, of 400,000 ohms, limit the grid current.
will assume a slight negative potential while the ;Ici, Li It is seen, therefore, that, as tube |09 Iires, a
capacitor ||1 is charging, being connected
momentary voltage surge of approximately 146
through capacitor ||1, of .00005 microfarad, to
volts positive is impressed across the .00005-mi
point H0, through resistor |45, of 400,000 ohms,
crofarad capacitor ||1 to point ||8 and causes a
to point |40, which is located between resistors
positive voltage impulse of about 146 volts to be
|4|, of 75,000 ohms, and |42, of 100,000 ohms, i. impressed at said point ||8. Point | I8 is normal
connecting the 150-volt negative conductor 95
ly at a potential of 64 voltsne'gative with respect
with ground. When the capacitor ||1 has be
to ground, being connected through resistor |45
come charged and current no longer flows in this
of 400,000 ohms to point 140 between resistor I4!
circuit, the point ||4 will be at ground potential.
of '15,000 ohms and resistor |42 of 100,000 ohms
The slight negative potential rise of the cathode
connecting the ground conductor with the 150
|08 will not cause the tube |09 to be fired, be
volt negative conductor 95.
cause the grid |01 at this time has a potential of
The grid of the “l” digit-representing tube is
150 volts negative and the tube is of the type`
connected, through resistor |50 of 100,000 ohms,
that will fire and conduct current from the cath
to the point ||8 and assumes its normal poten
ode to the anode when the grid has a positive 50 tial of 64 volts negative, which changes to a posi
potential or a potential less than 15 volts nega
tive potential of about 82 volts when the start
tive with relation to the grounded cathode.
ing tube ñres and impresses the positive poten
Upon closing the starting switch |00 after the
tial surge of 146 volts to point ||8. When the
main switch 90 has been operated, the F10-volt
main switch 90 is closed and the 150 volts nega
positive terminal 9| is connected to the point |00 55 tive potential is applied to conductor 95, current
in the circuit from the 150-volt negative con
will flow in each of the circuits associated with
ductor to the grid |01, which connection is from
the digit-representing tubes, such as the one
terminal 9|, through starting switch |00, through
traced earlier herein from the 150-volt negative
the normally closed switch |46, resistor |0| of
conductor through resistor |3|, point |29, switch
200 ohms, resistor |02 of 100,000 ohms, switch 60 |04 in normal position, resistor |30, point |23,
|03 in its normal unoperated position, conductor
paralleled resistor |25 and capacitor |35 with re
|52, switch |04 in its operated position, and con
sistor 90| in series therewith, output conductor
ductor | E0 tothe point |06, to which the grid | 07
|50, point |24, and, through resistor |20, to
is connected. This application of 170 volts posi
ground. The potentials of the points |123 and
tive potential to the point |00 will cause the po 65 |29 will become iixed after capacitor | 35 becomes
tential of the grid |01 to change from 150 volts
charged, andthe only current ñow will be that
negative to about 9 Volts positive with respect
determined by the resistors. Under these con
to the grounded cathode and will cause the start
ditions, the point |23 and cathode |20 of the “1”
ing tube |09 to ñre and be conductive. The ca
digit-representing tube connected thereto will as
pacitor ||| of .005 microfarad in the circuit con
sume a potential of about 19 volts negative, point
necting grid |01 with the 150-volt negative con
|29 and the grid |32 of the “2” digit-representing
ductor 95 acts to slow down the application of
tube connected thereto will assume a potential of
the firing voltage to the grid |01.
84 volts negative, and point |24 and the output
When the starting switchY |00 was closed, as
conductor |50 connected thereto will assume a
noted above, it also connected the plate ||_0 of _ 'f potential of13.2 volts negative.
When the starting switch |00 is operated after
the main switch 90 is closed andthe "2” digit
key is depressed, the T10-volt potential is ap
plied to plate |22 of the “l” digit-representing
tube through a circuit tracedfrom terminal. 9|,
|25, there will be a potential drop across` this re
sistor which will increasefas'thecapacitorïbecomes
charged and >more current flows’through the re
sistor. Under these conditions', the positive po
tential of point |24 and the output conductor |50
operatedV starting switch |00, switch |45, through
will. decrease as the‘dropv across the resistor ~|25
resistor |0| of 200 ohms, conductor |44, and
through operated switch |43".
With the grid | I9 of the “1” digit-represent
ing tube normally at the same potential, 64 Volts
negative, as is point H0, and the cathode |20 at
increases, while the potential of the point ’|23
remains unchanged, so that, whilefthe potential
of the grid '|32 remains at 2.5V volts positive, the
potential of the cathode |21 will drop below 17.5
volts positive, at which time the grid |32 'willi be
a potential of 19 volts negative, the gaseous tri
ode “l” digit-representing tube 12| is kept from
more`V positive than l5 Voltsnegative with respect
to the cathode |21 and the “2” digit-representing
When the 14S-Volt positive potential impulse, '
caused by the ñring of the starting tube, |00, is
impressed upon the grid ||9 of the “1” digit
representing tube l2 l, it is apparent that grid | i0
will become temporarily about 82 Volts positive
with respect to ground, or 101 volts positive with f
respect to the 19-volt negative cathode |20, and '
the tube |2| =wil1 ñre. The voltage impulse at
point H0 which rires tube |2| is kept from ground
ing by resistor |45 of 400,000 ohms. Resistor
|50` of 100,000 ohms in series with resistor |45
limits the grid current of gridl I0.
When the tube |-2i ñres and the gas therein
becomes ionized, the internal resistance of the
tube drops and thepotential difference between
plate |22'and'cathode |20 drops toabout 15 Volts, ,«
tube |28 will-fire -and be conductive.
Theprovisicn of the 2,500-ohm resistor, like
resistor 00| (Fig. '7), in series with e'achof- the
capacitors corresponding to capacitor' |3‘51is' to
repress any tendency toward' oscillation inthe
anode-cathode circuits of' the electron discharge
tubes. ` The introduction of such oscillation
preventing resistors into the circuits',` así-shown,
prevents. the occurrence of chance oscillations
which may be caused by the distributed induct
anc‘e and capacity of the circuits. Such 'chance
oscillations would tend to extinguish the .last’tube
of the series to ñre and, by thus'causing an
anomalous negative pulse on conductor> |50,v fire
some other tube-inthe bank.,
The oscillation resistors .correspondingto re
sistor 00| have a slight effect in Vreducing the K
so that cathode |20. and point |23 will have a
amplitude ofthe positive rise in potential'of the
potential slightly less'than 155 volts positive with
reference to ground. It should be noted that
the resistor |50| of 200 ohms in the plate cir
cuit is much smaller than the resistors |25 and
|25 totaling 30,000 ohmsV in the cathode circuit,
, output conductor |50~`asthe capacitor |35 is being
charged, but do not affect the» operation of the
sequential firing of the tubes as explained.
Through the same circuit as that described
above >in connection with the “1” digit-_represent-l
andthe voltage drop‘across theresistor |0| will
ing tube, the plate ciI the “2” digit-,representing
have but little effect in- changing the potential of '
tube has impressed thereon aY potential of about
170 volts positive. _The cathode circuit for the
“2" digit-representing tube is similar to the one
plate |22 whenthe tube ñres.
At the moment the tube ñres, the current in
the cathode circuit* between points |23 and | 24
momentarily willbe principally through the ca
pacitor |35-and resistor 90|, and very little will
flow through the resistor |25, so that there will
be a very small'voltage drop across this resistor.
Point |23 will Vhave a potential of 155 volts posi
tive With respect to ground, and point- |24 ‘will
be slightly less. As4 the capacitor |35 becomes
charged, more current willv flow through resistor
|25, and the potential drop across the resistor
|25 will cause the point |24 to become less posi
tive in potential while point |23 maintains the
same potential. The rise of the potential ofthe
cathode |20 toward 155 volts positivewill cause
the grid |32 of theV “2” digit-representing tube
|28, which is connected to point |23' through
resistor |30, unoperated switch |04, point E29,
for the “1” digit-representing tube, so that, .as
the “2” digit-representing tube |28 fires, its
cathodel |21 rises to a positive potential of' about
155 volts and the potential of output conductor
|50 also rises toward 155 volts.
Just as in' the
,case of theV “1” digit-representing"tube, thispo
tential drops off after capacitor. |34l becomes>`
charged‘and current flows through resistor |31.
Since the “1.” digit-representing` tubeiscon
ducting when the “2” digit-representing tube
fires, its cathode |20 is at 155 Volts and the surge
of positive potential impressed upon output con
ductor |50, when the “2” tube fires, feeds back
through resistor 90| and capacitorV |35 and
causes thel cathode |20 of the “l” digit
representing tube to have a temporary potential
rise abovelthe 170-volt positiveipotential ofthe ‘
and resistor |51, to change .from its normal nega
plate |22 and causes the current to stop flowing
tive potential of 84 volts to a positive potential
of approximately 2.5 volts. Thisv change. in po 60 in the cathode-plate circuit, extinguishing` the
tube and allowing the grid | I0 to resume control.
tential of grid |32 will not cause the “2” digit
Point |30, normally at a potential of 84'volts
representing tube to i‘lre immediately,.because the
negative were switch |5| in normal position,
point |24 and conductor |50 approach the same
would be affected by the ñring of tube |28‘in' the
potential as point |23 when the capacitor |35
begins to charge, an‘dtherefore the cathode |21
of the “2” digit-representing tube, which cathode
is connected to output conductor`|50 by the re
sistor |31 and capacitor. |34 in series` with re
sistor 920, in parallel, will have a potential change
similar to that of grid-|32- 'and will» retain the ef
fective biasing potential difference between the
grid |32V and cathode |21 of the “2” digit-repre
senting tube; preventing the tube frornñring
during this period. As the‘icapacit‘or |35 becomes
charged and current. begins-to ilow in resistor
same manner as point |20 was affectedfbyîth’e
ñring of tube |2| and would cause the potential
of the grid for the “3” digit-representingk tube
to be raised to 21/2 volts positiveffiring the
“3” digit-representing tube as the “2” digit
representingi‘ tube was fired', Y.but instead, by
opera-tion of the “2” key 62, the grid of the “3”
digit-representing tube is connected only to the
15G-volt negative conductor 95, giving it acon
trolling bias potential even though its cathode
vrises in potential asthe conductor li'rllïrises'in~>y
potential when the “2” digit-representing tube
in the bank will not be extinguished until the
|28 lires.
It should be noted that the cathode of the
digit-representing tube corresponding to the de
pressed digit key is not connected to the 150
volt negative conductor 95 by the usual circuit
to which is connected the grid of the digit
representing tube of next higher value, .but is
connected by a switch as |5|, shifted by depres
sion of the key, to impulse firing conductor |52.
This conductor |52 extends to the tens denomi
nation bank of the differential actuator and, if
switch |46 opens.
a key is depressed in the tens bank as shown in
' In the above description of the operation of
the differential actuator, only two digit tubes
were considered,
When the full bank of nine
digit tubes is considered, certain of the poten
tials will vary, due to the increase in the number
of parallel Circuits between the output conductor
and the l50-Voit negative conductor 95, one cir
cuit being provided for each tube except the “9”
digit-representing tube. The circuit for the “1”
digit-representing tube is representative and has
been traced as follows: from the 150-volt nega
Fig. 6, said conductor is connected by operated
tive‘conductor 95, through resistor |3i, point |29,
switch | 9| to a circuit which extends through
switch |54, resistor |30, point |23, resistor
resistor |59 of 100,000 ohms and capacitor |05V
and through resistor 90| and capacitor |35 cp
of .005 microiarad, in parallel to the 15G-volt
nected in parallel to resistor |25, to output «sort-"f5-u
negative conductor, and if no key is depressed in
ductor |50 and point |24, which are connected
this bank, extends to point 212 where it is con
to ground through resistor |26. `As the number
nected through resistor |58, or” 100,000 ohms, 20 ol' parallel circuits increases, the eiîective resist
and capacitor 620, of .005 microfarad, in parallel
ance of the circuit between the l50-volt negative
to the 150-volt negative conductor 05.
conductor 65 and output conductor |50 decreases
Therefore, switch |5| having been operated to
and the potential drop across this part of the cir
make contact with the firing impulse conductor
cuit decreases, causing an increase in the nega
|52, the positive potential surge of point |33 is
tive potential of output conductor |50, the points
transferred to the nring impulse conductor |52 to
corresponding to point |23 and cathodes con
be conveyed to the next denomination, there to
nected thereto and points corresponding to point
be switched by an operated switch as |6| to the
|26 and grids connected thereto. Since the
point |56 to impress the positive pulse on the
cathodes and grids have corresponding rises in
grid of the starting tube |54 to nre the starting 30 potential, the variation will not cause the tubes
tube |54 of the tens denominational bank
t0 fire. When the nine digit-representing tubes
(Fig. 6) if a digit key in that denomination is
are'consiclered, the normal potential of the out
depressed, or to be shunted to point 212 to im
put conductor |50 is 22.6 volts negative instead of
press the positive pulse on the grid 201 to fire the
3.2 volts negative, 'the normal potential of the
key release control tube |55 if n0 key is de 35 cathodes is 36.7 volts negative instead of 19 volts
pressed. »As many tubes will ñre in sequence in
negative, and the normal potential of the grids is
a denominational bank as are represented by
93.3 volts negative instead of 84.5 volts negative.
the number of the key depressed in that bank,
Itshould also be noted that, when the full bank
the starting tube excepted. As each digit
oi’ nine digit-representing tubes is considered,
representing tube is fired, a positive voltage im 40 the potential surges impressed on the output con
pulse oi about 146 volts occurs in the denomi
ductor will cause the potentials of the cathodes
national output conductor corresponding to con
and grids of the other tubes in the bank to Vary
ductor |50 or conductor |53, which impulses ac
with the potential of the output conductor.
tuate the accumulator in a manner to be de
However, the only grid which receives a sustained
45 rise in potential will be the one connected to the
When any digit-representing tube in a de
cathode of the tube which has just fired, and the
nomination is conductive and the capacitor in
sustained rise of this grid will cause such next
its cathode circuit is charged, the output con
tube to nre when the cathode potential oi such
ductor for that denomination will have a positive
next tube recedes to a point where the grid is less
potential of about 26 volts and the cathodes 0f 50 than 15 volts negative with respect te the
other tubes in that denomination will be changed
from a normal negative potential of 19 Volts to
A potential change delaying arrangement is
a positive potential of about 6.5 volts. The shift
provided for each of the starting tubes for slow
of the potential of the cathodes of the digit tubes
ing the application of the positive potential to
from 19 volts negative to about 6.5 volts positive 55 their grids, which delays the nring of the start
will not cause the tubes to fire, because the grids
ing tube in each denominational bank to allow
are at about 72 volts negative potential at this
time for the transfer of carry-over data to be
time. The values selected for the cathode re
made from the next lower denomination of the
sistors and capacitors depend on the potentials
accumulator before the key set data is entered
oi the supply conductors and the speed of opera 60 from the differential actuator, thus avoiding pos
tion desired.
sible interference of the entries. This arrange-l
The grid resistors, the` cathode resistors, the
ment, for example, is seen in the circuit be
cscillation-suppressing resistors, and the timing
tween the grid |01 of the starting tube |09 and
capacitors are of the same values for all the digit
the 15G-volt negative conductor 05 and comprises
representing tubes in each denomination. The 65 resistor |05 and capacitor || |.
firing of the digit-representing tubes “l” and “2”
The key switches corresponding to switch |l|3in sequence, followed by the extinguishing of the
(Fig. 7) connect to the anode plate supply con
“l” digit-representing tube and the operation of
ductor |44, all those tubes of the bank which are
the key release solenoids and single operation
of a digit value equal to or lower than the key
switch iüiâ, as described in connection with Fig. 70 depressed, and are to be iired in the sequence.
7, is typical of the operation of the differential
By the plate potential supply switches, like switch
actuator. It is to be noted that there is no means
|43, it is therefore possible to cut out the plate
to extinguish the “2” digit-representing tube |28
supply of all the tubes representing digits; higher
until switch |56 opens; therefore, at the end of
in the order than the digit represented by the
a data-entering operation, the last tube to ñre 75 digit key depressed, and to impress upon the out
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