US2404697A - Calculating device - Google Patents

Description

y 23, 1946- J. R. DESCH ET AL CALCULATING DEVICE 4 Sheets-Sheet 1 Filed March 21, 1942 r- A a C m/ o 9 Q n// 0 O y r d m u m w C m 3 U M a P 4 2 o 5 a Z a 7 m m 0 W 3 joscph R. Desch and Robert E. Mumma Their Agongy y 23, 1946- J. R. DESCH ET AL CALCULATING DEVICE 4 Sheets-Sheet 2 Filed March 21, 1942 HQ. 2 flenomma f/ona/ I 0/5 fr/ /ar jmrph R. Desch and Robert E. Mumma Inventors By W Their Attorney y 1946- J. R. DESCH ETAL CALCULATING DEVICE 4 Sheets-Sheet 4 Filed March 21, 1942 Jose h R. Beach and rt E. Mumma Inventon Their Attorney Patented July 23, 1946 CALCULATING DEVICE Joseph R. Desch, Oakwood. and Robert E.

Momma, Dayton, Ohio, assignors to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Application March 21, 1942, Serial No. 435,740

21 Claims.

This invention relates to an electron tube calculatlng device and more particularly pertains to such a device for the ultra-rapid multiplying of numbers, expressed in the binary system of numerical notation, by the use or differentially controlled electron tubes.

The invention includes a product accumulator having electron tubes representing the digits, which tubes are actuated by electric impulses, a diflerentially-controlled electri potential generator having electron tubes representing the digits comprising a multiplier, a differentially controlled electric impulse generator having electron tubes representing the digits of a multiplicand, and an electron tube impulse producer and switching means to distribute the impulses produced under control of the multiplier and multiplicand units to the proper denominational orders of the product accumulator. The invention further includes certain manual controls for introducing the problems and for starting and resetting the devices.

The disclosed device is based on a numerical notation having two digits in each denominational order. which is known as the binary system of numerical notation. The digits are designated no (1-) Therefore it is the principal object of this invention to provide an electron tube multiplying machine in which the calculation i performed solely by the flow of electrons.

Another object of the invention is to provide a multiplying machine having no moving mechanical parts except for manual entry of the problem.

Another object or the invention is to provide means for producing denominationally-designawd impulses in groups which are distributed by stages to selected denominations oi an accumulator.

Another object of the invention is to provide an electron tube denominational distributor, for denomination representing impulses, controlled iointly by a multiplier unit and a multiplicand unit.

Another object or the invention is to control an electron tube diflerential impulse generator to repeat its operation a certain number of times automatically.

Another object of the invention is to provide means to multiply two binary numbers by operating electron tubes difl'erentially and cyclically.

With these and incidental objects in view, the invention includes certain novel features of construction and combinations of elements, the essentials or which are set forth in appended claims and a preferred i'orm or embodiment or which unit.

Fig. 5 is a parallel table of binary notation and decimal notation.

In the binary system of numerical notation, there are but two digits, designated "0" and 1. The absence of data in a denomination is represented by "0," and the presence of a unit of data in a denomination is represented by "1." On the addition of another unit of data in a denomination having at that time a unit of data therein. there are a return to the 0" condition 01' said denomination and a transier of one unit into the next higher denominational order. The following examples of additions of one unit at a time will give an understanding of the numerical system.

Eauivslcnt 0 ecimal plus 1 notation equals 1-? -1 plus 1 nudism-2 -2 plus 1 e usuT-Hnu plus 1 equals -2 plus 1 Multiplication in the binary system by partial products is accomplished in the same manner as in the decimal system; for instance.

101 E5 in the decimal system; ll 8 in the decimal system equals E (us in the decimal system, or n+2 +m+2o Bins-y Decimal 11001 ll Xllllll X25 11001 25 11M 20' 11M 3 1 at 28 1001110001 25 25 It is seen, therefore, that in the binary system the entry or data into the product accumulator need be made on y once ior each denominational order or the multiplier and that. in substance, the multiplication of binary numbers is the same by successive addition as it is by partial products.

The product accumulator The product accumulator (Fig. 1) as disclosed comprises six denominational orders. Each of thedenominations is represented by two gaseous triode electron tubes, one tube representing "0 and the other tube representing 1." The tubes of a denomination are coupled in such a manner that, when one tube of a pair commences conducting, the other tube or the pair is caused to become non-conducting. The pairs or tubes, each pair or which forms a denomination. are arranged in a series 01' ascending value, so that, upon a tube representing "1 becoming non-conducting, a change or mode or operation of the next higher denominational pair is brought about. The scheme or data representation in the accumulator will be described. The denominations will be designated 2, 2 2', 2 2 and 2', so that their decimal equivalents may be easily followed. The tubes are represented by circles. The "1 tube in the denomination 2 represented as conducting as an example, by being blackened, represents an accumulation oi 10000 in the binary system or "16 (2') in the decimal system.

The zero condition 01 the accumulator is evidenced only when all the "0 tubes are conducting, which event is brought about by a special control.

Each denominational pair of tubes in the product accumulator is provided with input means y which actuating electric impulses are impressed on the pair, such impulses originating by the difi'erential action or multipiier-multiplicand units or by reason of the "1" tube of the next lower denominational order becoming non-conducting.

Each impulse represents a unit or data and causes a change in the mode of operation or the electron tube pair upon which it is impressed.

The orders or the accumulator have data entered therein in sequence the entry 01 the multiplicsnd as multiplied by one digit of the multiplier being made denomination by denomination with the highest of the concerned orders oi the accumulator. Thus, it the multipllcand "111 were being multiplied by the particular digit "1 representing the denomination 2, the iirst entry would be made into the 2 denominational order of the accumulator, the second entry into the 2 denominational order, and

4 thethirdentryintotheQ'ordensaideni-riesking made successively. By thus arranging the successive entry oi data in the accumulator, in terierence oi the multiplication impulses and the interdenominational transfer imp lses is positively avoided, and not dependent on timing.

The accumulator, although shown to but six denominations, may be made in any number 01' denominations.

It is seen by rei'crence to Fig. 1 that, there being sixjdenominations in the product accumulator, it will accommodate in one operation the product obtained by multiplying a three-denominational-order binary number by a three-denominational-order binary number.

The gaseous triode electron tubes are or the type which has an internal voltage drop, when conducting, of about 16 volts. The cathodes are indicated conventionally as being heated, and each is grounded for operating potential through arcslstancelikercsistance l2. Atypicalsetol circuit values will be given the circuit elements.

the 12, for example, being 15,000 ohms.

Theanodesoreachoithetubesaresuppliedwith 25 positive potential from a lb-volt source ll. controlled by a switch II, which energizes a supply conductor is common to all the tubes in the ac cumulator. From said common supply conductor ll, each pair of tubes constituting a denominagg tional order is supplied through abranch conductor such as conductor ii through a 3000-ohm resistor such as resistor ll, whose iunction is for a P p e to be described. Each of the cathodes is rurther coupled to ground through a capacitor like capacitor II, or .001 microtarad, and a series resistor, like resistor 10 of'2500 ohms,- the resistor ll being introduced ior prevention oi. oscillatory phenomena. Each rid is biased from a negative source or potential 20 through a renstor like resistor Ii 01' 120,000 ohms, a point like point 2!, a resistor like resistor 23 of 500,000 ohms, a point like point :0, and a resistor like resistor 25 or 50,000 oh'ms. Points like point 22 are also rounded through a resistor like resistor 20 oi 50,000 ohms. This gives each grid, normally, a controlling bias oi about 12 volts over the critical Potential.

connect the grid oi an associated "0" tube to ground, so as to ground the control grids oi all the zero tubes simultaneously to cause the product accumulator to represent zero by causing all the zero digit tubes'to become conducting.

Assuming the product accumulator in more condition, the method of counting data therein will be described first by supposing a positive potential impulsetobeintroducedthroughtheii inputtermlnal 20, said impulse being or such potential that, when it is impressed through capacitor 00, or 10 micro-microierads, through point It and resistor it onto the grid of the "1 digit tube or the 2" denominational order, it will cause said digit tube to lire and become con anode oi said tube, due to the roaster thereupon drop in potential, as the temporary grounding eiiect oi capacitor i0 holds the anode at that potential, such anode potential being temporarily teiy 16 volts above the ground. Atthesame timasuchsnode dropinpotential iscarriedbyconrluetorittotheanodeortuhs ii, which is in-a conducting condition andwlmse cathode is maintained at a poliflve potential or m volts, determined ducting. The

i1,"will byresistorl,of15,000ohms,hythedischargeof the capacitor 8!, so that the anode of the tube Ii temporarily becomes more negative than the cathode, allowing the grid to resume control, whereupon the tube ii becomes extinguished. Thusthesingleimpulseiseountedinthefl'order of the product accumulator by leaving the "1" tube in a conducting condition.

Upon the introduction of. the second positive impulse through the 2 terminal 2!, the 0 tube will be fired and become conducting, whereupon the "1 tube will be extinguished, its grid resuming control. The rise in the potential 0! the cathode of tube Ii, as it fires and becomes conducting, is impressed on conductor 32, through point 33, and through capacitors 34 and 15. causing the "1" tube of the 2 denominational order oi the accumulator to tire and become conducting, thereby causing the zero tube of the same order to become extinguished. No matter which tube of the succeeding order is conducting, because the interdenominational transfer impulse is impressed through both capacitors, such as capacitors N and 35, it will always cause the non-conducting tube to fire and the conducting tube to become extinguished. The accumulator, after the supposed introduction of two impulses through terminal 29, now shows an accumulation of two units of data, or, expressed otherwise, data representing 2 Data introduced over terminal 30 represents, for each impulse, unit data of 2 as such an impulse introduced over terminal It will actuate tubes 11 and III to change their mode oi operation from what it then is, and to cause a transfer of data to actuate the succeeding denominational order if such change in the mode of operation of the pair results in the zero tube becoming conducting. In the same manner, a single impulse over the terminal Iii will introduce in the accumulator a unit of data in the value of 2", an impulse on terminal ill will introduce into the 2 denominational order a unit of data equal to 2 for each impulse, and an impulse on terminal ll will introduce data equal in value to 2 for each impulse. The total capacity of the disclosed accumulator as noted in the binary system is "111111." which is "63 as noted in the decimal system. Since the maximum multiplication accomplished by the structure disclosed is "ill" by "111" in the binary system. which gives a product or "ll000l in the binary system (49 in the decimal system), it is seen that the said accumulator is ample to take care of any problem that can be set up in the three place multiplier and the three place multiplicand units. The invention as disclosed permits the number of denominational orders to be increased indefinitely to accommodate more denominations for carryover data or to accommodate a larger product.

The terminals 29, 88, I9, 40, and ll are connected to the denominational distributor or the generated impulses, as will be described. No input terminal is furnished for the 2 denomination of the accumulator, as that denomination receives data only by denominational transfer.

The denominational distributor The denominational distributor (Fig. 2) relays and distributes impulses produced under joint control of the multiplier-multiplicand units to the product accumulator to actuate it. There are three input control conductors from the multiplier unit to the denominational distributor, ending in terminals 50, s2, and I3, representing, respectively, the 2, 2 and 2 denominational orders of the multiplier. There are three input control conductors from the multiplicand unit to the denominational distributor, said conductors ending in terminals ill, II, and 0, representing. resp tively, the 2', 2 and 2 denominational orders of the multiplicand unit.

These conductors convey certain potentials to the grids of nine gaseous triode electron tubes. each being rendered conducting under control oi associated portions of the multiplier and multiplicand units and thereafter having a self-extinguishing action. The combined influence of a potential rise in a conductor from the multiplier unit and a potential rise in a conductor of the multiplicand unit causes the firing or a particular one of the nine self-extinguishing tubes of the denominational distributor, creating a potential impulse which is routed to the proper denominaticnal order of the product accumulator to actuate it. The three input conductors of the multiplier combine with the three input conductors of the multiplicand to give nine possible results, each of which is represented by one of the nine tubes of the distributor. A typical problem will give an understanding oi the function 01 the distributor. For example, multiply in the binary system "111" by "111." This problem will identify the function of each of the tubes in the denominational distributor, as it provides a digit in every order of every stage of the multiplication. As has been said, the highest digit of the multiplier is first used, and therefore the problem may be expressed in this manner:

2 2 2' 2! 2 2" (Denominational order) X l l l (multiplicand) -2'+2 +2' l l l (multiplier) -2'+2 +2' m 1 (second stage; -2 +2 --2 l l 1 (third stage i i-f It is seen that. in the first stage of the multiplication. the highest order multiplier digit is employed, which is, in the denominational distributor, represented by the multiplier terminal Ill (Figs. 2 and 3). This terminal is connected to the grids of the gaseous triodes ii, 52, and 53, whose cathodes are respectively connected to the product accumulator terminals 89, 40, and ll, leading to the product accumulator banks (Fig. 1) representing 2, 2 and 2 Referring to the first stage or the multiplication, it is seen that a unit of data is to be entered into each of the lastnamed denominational orders of the accumulator. By impressing a positive potential on terminal 60 (Fig, 2) suflicient to relieve th bias on the grids of tubes ii, 52, and It to a point just short of firing, each of the said tubes Ii, 52, and I! is primed to be responsive by firing. If the grid of any one of the primed tubes is given a positive potential impulse by the multiplicand unit, through associated respective terminals 80, II, and 82. suflicient to overcom th relieved bias, such tube will fire and become conducting. Such multiplicand impulses are adjusted so as to be insumcient to fire tubes or the denominational distributor which are not relieved of the full bias potential. The cathode of a fired tube will rise in potential, due to the resistance in the cathode supply circuit, delivering a positive potential impulse to the associated one of the terminals It. 40, and ii actuating the corresponding bank of the product accumulator. The cathode of the tube Ii (also connected to the cathodes of tubes BI and it) is connected to ground through resistor M of 50.000 ohms by means of conductors II and 00. The cathoderesistor ll is.common totubesll andlhthe'cathodeoithetubell beingconnectedthereto conductor II. The cathode resistor is is connected alone to tube It. ll licondterminals a positive potential immusejin sequence, begin-- with terminal andending withterminal 02, for each stageoi the multiplication. In problems in which there isno mult p ying sh in a given denomination, no impube" i'onthat denomination reaches th distributor. 00;

e; 2,is coupledby conductor 00 to the lrldsoftubes II, 00, and I! each through a capacitor like capacitor-0| of micro-microiarads. 'In the same manner, the grids of the tubes 02, II, and I! are coupled, each through a capacitor, to the common conductor lloonnected to the terminal 0i representing the 2 denominational order of the multipllcand. and, in a like manner, each of the tubes II, II, and i2 is coupled, through a capacitor, to a conductor I0 con such as mt tired by first impulse being impressed on the terminal 4i,

the second on the terminal 00, and the third on he terminal 09.

After one of the tubes 01' the denominational distributor has fired and become conducting, it is self-extinguished by reason or the fact that the cathode and anode of each tube are each dynamicallv coupled to ground, which tact, in conjunction with a resistance and capacitance in parallel in the cathode supply, and the distributed inductance in the anode-cathode circuit, causes an oscillatory rise in cathode potential which over shoots th anode potential, extinguishing the tube. For tube 03, for instance, the capacitor II or 100 micro-microiarads, the resistor 00 of 50,000 ohms in the cathode circuit, and the large capacitor 16 coupling the common anode supply to ground constitute such a self-extinguishing circuit. The tubes 02 and 04 are both served by the resistor 01 and the capacitor DI, the cathodes or both tubes being connected by conductor 00. a

In the same manner tor tubes 05, 00, and ii, whose cathodes are connected by conductors and 00, the resistor 04 and the capacitor I0 supli e relatively ply the self-extinguishing circuit elements. For a the tubes "and ii, the resistor 11 and the capacltor II serve the same purpose by reason or the common conductor ll. The tube 12 is served by the resistor 00 and the capacitor Ii. The cathoderesistors and capacitors are thesamei'orall the distributor tubes.

Th operating potentials are supplied as follows: for the anodes, 76 volts positive, and for the which normal potential, b

normal grid bias, 150 volts negative. This lid-volt negative supply is obtained by connec- V tion to e minal II. V

throughthetermineis Immoral t rize multiplier e negative lot grid. is

under which ac essi n-ma m sur ments we h itii'ethan 10 volts 'negative with to thods, by vfrom the multiplicand causing such primed tubes to resistors 00 and 00 (Fig. 2) are or 500.000 ohms, respectively. Resistors; such as resistor 00 are oi 350.000

A switch ll isprovided to complete the anode uppl! j toalltheselr-extinguishingtubes or the denominational distributor unit. 7

a The multiplier unit a "I'he multiphrlil lg. 3) includes four gaseous triodes, three oi them, I00, IN, and I02, represendin he denominational orders 2=, 2 and 2 of the multiplier, the iourth tube, I00. being a stop tube. Thetubes' I00 to I00 are caused to be operated in sequence, the first of said tubes, tube momentarily closing a switch I, --which grounds the grid. The remaining tubesili, i0l,'and are calmed to become conducting in sequence in response to positive potential impulse signals received through terminal III, which impulses are received from the militlpliound unit (Fig. 4), as will be described. The anodes oi' the tubes of the multiplier are upplied, through theterminal ill, under control 0! a switch ill, with '75 volts positive potential, thro h a resistor I00 0! 3,000 ohms and a common conductor I00.

The cathodes of cache: the tubes I00, ml, and iii! are grounded through a 15,000-obm resistor, resistor i in, in parallel with a capacitor oi .002 inlcrofarad, like capacitor iii, in series with a resistor-oi 2,500 ohms, like resistor H2. The grids or each of the tubes Ill, I02, and I00 are givennegative bias through the resultant sheet or onnection to terminal H3 or volts negativeiwith respect to ground, through a point like point ii], through a network 01' resistors, like resistors H0 (or 00, Fig. 2, when key switch 2 is closedLiii, III, H1, H0, and iii oi the values 350,000 ohms, 200,000 ohms, 200,000'ohms, 300,000 ohms,500,000 ohms, and 50,000 ohms, respectively. Points like point I50 are connected to the cathode of the preceding tube oi the series at a pointlike point I02, which is grounded through a resistor like resistor I20 of 15,000 ohms. This gives the grids oi tubes I01, J02, and! a normal negative bias or 57 volts with'r'espeet to their cathodes, which is sufiicient to prevent the firing ot saidtubes, their cathodes being connected to points like point 102 to give them a negative potential in the normal non-conducting condition 01' 8 volts. The grid of tube I00 is given a controlling negative bias oi. 150 volts with respect to ground by being connected to" point I through a 500,000-o1nn resistor I 00.. Basistor I0! is of $5 0,000 ohms instead of the'30.000 ohms stated ior other corresponding resistors.

The closing oranyone or the keys 2*, 2 oril" (F1:- 3) adjusts th mes on thegrid or the easeoiated tube oi" the multiplier unit Bud, the'ihssoelated tubes of the horizontal row of natlonaldistributor, m k ng the bias onitheffgrids or the tubes or the denominational distributor (Fig. 2) as are associated with th depressed closed key. about 59 volts negative. The consequent potential upon the grids or the multiplier tubes of the next lower denominational order will be about 65 volts negative.

As the key switch I04 grounding the grid of the 2 tube I00, the tube I tires and becomes conducting, and the terminal 50 (if key 8| is on the lower contact), connected to the cathode of the I00 tube through resistor I88, is given a potential rise of approximately 36 volts. which results in relieving the bias on the grids of the tubes SI, 52, and 53 of the denominational distributor (Fig. 2) to approximately 23 volts negative.

When an impulse is impressed upon the terminal I (Fig. 3) from the multiplicand unit, it is thereby impressed upon the grids of the tubes IOI, I02, and I03 by means of a common conductor I22 and capacitors, such as capacitor I23 of micro-microfarads. As the grid of tube IN is connected to point I24, it receives a positive elevation of potential while the tube I00 is in conducting condition, which causes the grid of tube IOI to be relieved 0r primed so as to be more susceptible to filing than the tube I02 or I03, and consequently the potential impulse impressed on the terminal I05 is made of a value which discriminates between the primed and the unprimed tubes, and fires tube IOI, whose grid is connected to the cathode of an already conducting tube. Therefore, when tube I00 is conducting, only tube IOI will fire in response to an impulse from the multiplicand unit. When tube IOI fires, its cathode capacitor I25 of .002 microfarad will begin to charge, and, due to the common 3,000- ohm resistor I08 in the anode potential supply line, a sudden drop in potential in the conductor I05 occurs, with a consequent drop in the anode potential of the tube I00, which previous to that time has been within about 16 volts of the potential of its cathode. Such sudden drop in the potential of the anode of tube I00 thereby extinguishes it, as its cathode potential is temporarily maintained by the charge on capacitor I I I. Thi extinguishing of one tube upon the firing of a. second tube by causing its anode potential to become less than the cathode potential has been explained before in connection with the product accumulator. It is seen that tubes IOI, I02, and I03 are caused to be fired step by step in sequence in response to the positive potential impulses impressed upon the terminal I05 by the multiplicand unit.

The firing of the tube I03 is only to provide a negative potential at the terminal I20, which negative potential is brought about by reason of the drop of the anode potential of tube I03 due to the resistance in its anode supply. Such negative potential is impressed upon the multiplicand unit to stop the recycling operation of the multiplicand tubes, as will be explained.

When tube I03 fires, capacitor I21 and resistor I28 together provide the circuit function in extinguishing any other conducting tube whose anode is given its potential by anode conductor I09, just as though the capacitor and resistor were in the cathode supply circuit of tube I03. Therefore capacitor I2! is of the same value as capacitor III, and resistor I28 is of the same value as resistor I I0. The resistor in the cathode supply of tube I03 is an oscillation-suppressing resistor of 2,500 ohms corresponding to resistor H2 having the same function for tube I00. By placing most of the resistance in the anode ciris momentarily closed, l

10 cult oi tube I03, a greater potential drop is available at terminal I2 0.

It is seen, therefore, that manually selected ones 01' terminals 50. 02, and 03 are caused to be given an elevation of potential, one after another, under control of the multiplicand unit, the keys like key 04 being selecting keys for setting up the digits of the multiplier.

The multiplicand unit The multiplicand unit (Fig. 4) includes tubes 200, 20I, 202, and 203 of the gaseous triode type, such as the, tubes heretofore considered. Tubes MI, 202, and 203 represent, respectively, 2, 2, and 2. The tube 200 is an operation recycling control tube. The multiplicand tubes are connected in a circuit whereby, upon initiation of an operation by firing the tube 203, the tubes 202, Mi, and 200 are caused to fire automatically and become extinguished in that order in succession. Recycling tube 200, upon firing, initiates the commencement of another sequential operation oi. the multiplicand unit by giving a positive potential elevation to the grid of the tube 203. When the terminal I26 (Figs. 3 and 4) receives the negative potential, due to the firing of the stop" tube of the multiplier, as has been explained, the recycling impulse of the tube 200 is blocked and the recycling of the sequential operation of the tubes of the multiplicand ceases.

Terminal 205 is the source of a -volt positive anode supply potential which is impressed on a. common conductor 205 when switch 201 is closed. A 3,000-ohm resistor 200 is included in the portion of said anode supply conductor serving the tubes 200, "I, 202, and 203. Each of the cathodes of said tubes 200 to 203 inclusive is grounded through a 15,000-ohm resistor, such as resistor 209, in parallel with a capacitor and resistor in series, like capacitor 2I0 of .002 microfarad and like resistor 2 of 2.500 ohms. Each of the grids, except as will be explained for tube 203, receives its biasing potential by being connected through a resistor oi 500.000 ohms, like resistor 2I2, a point, like point 2I3, a point, like point 282, and a resistor of 150.000 ohms, like resistor 2I5, to a negative l50-volt supply conductor 2I'I. Points like point 2I3 are grounded through a capacitor of 250 micro-microfarads, such as capacitor 222. Each cathode is connected to a point like point 2I5 through a resistor like resistor 2I0 of 75,000 ohms. Departing from the repeating pattern of the circuit elements of the multiplicand unit, the resistor H9 is of 150,000 ohms, the resistor 220 is of 50.000 ohms, the resistor MI is of 500,000 ohms, and the capacitor 230, coupled to the source of positive potential, is 50 micro-microfarads. With the values of the circuit elements shown, upon the closing of the start switch 223, which connects the positive potential conductor 205 through capacitor 230 to point 224 leading to the grid of the tube 203, representing 2 the grid of said tube 203 is caused to become sufliciently positive to fire said tube. and, upon said tube becoming conducting, point 225 rises in potential, which potential is impressed through Po 236, P88151101 20L point 202, point 2I3, and resistor 2I2 onto the grid of the tube 202, representing 2', which thereupon fires and becomes conducting. As tube 202 is becoming fully conducting, capacitor 2I0 is charging, which, by lowering the potential of anode I225 due to the common resistor 208 in an anode supply circuit. lowers the potential of the anodes of tubes "R," 2. 2 and 2, which i the "stop" I 1 drop in potentialoi anode more than 15 a recycling of the multiplicand at the time the "R" tube 200 fires the third time, tube 103 (Fig. 3) is also caused to tube 200, due to it firing. will not initiate the firing of tube 203 and a consequent recycling of the multipiicand. This stops the operation of the muitipiicand unit. itor 222 are timing capacitors, oi 50 micro-microfarads delays tial of the grid of tube 203 until the tential arrives over to terminal impulse as the associated relay Tubes 23!, 240, and 2" are self 250,000 ohms to the l-volt negative supply conductor 217. Points like point 252 are connected through a resistor like resistor 2 to a terminal like terminal 255, which may be connected by a key switch like switch 256 to ground. These switches, when closed, ground the ternninal 285 and reduce the bias on the grid of the associated relay tube. example, the closing of switch response to the potenrise received at point 238 as tube 201 fires.

as fires. its cathode rises in potena positive impulse as the tubes 01' the multiplicandflreinsuccession.

It is apparent that, as far the invention is concerned, the

digit-representing tubes of the multiplicand unit. The tubes 289. 240, and 24!, being self-extinguished by reason of their resistance-capacitance couplingto ground, pass on the impulses and are ready for thing on the next cycle of operation or the multiplieand unit.

tiplicand keys are closed (Figs. 3 and 4), the key ID of the multiplier (Fig. 3) is closed, and finally the start key 223 (Fig. 4) is closed. Under mulator according to the following schedule:

In tter- In at ternais to m unis to distributor product the circuit elements that have The values for been presented in l3 candtubenot selectedisnotconveyedto thedenominational distribute Thereiore, no matter what the size of the multiplier or the multiplicand, the time consumed in one multiplying op. eration is the same.

Instead of the method of selecting the digits of the multiplier and the multiplicand by key switches, wherein the control is located between the multiplier or the multiplicand and the denominational distributing unit, the. same results could be gotten by bridging the connections between the multiplier tubes or the multiplicand tubes so as to cut out any particular tube not wanted in the sequence oi operation, or stopping the operation of selected tubes in any manner.

A table of binary-decimal equivalents is given in Fig. 5 for convenience.

While the form of the invention herein shown and described is admirably adapted to iulflll the objects primarily stated. it is to be understood that it is not intended to confine the invention to the one form or embodiment herein disclosed, for it is susceptible oi embodiment in various terms all coming within the scope oi the claims which follow.

What is claimed is:

1. In combination a plurality of electron tubes each representing a denomination of a multiplier so connected in a circuit that they are operable one at a time in sequence in response to each of commonly received electric impulses; and a second plurality of electron tubes arranged in a chain, each plurality representing a denomination of a multiplicand so connected in a circuit that conduction in one tube renders the next tube in the chain conducting, said group being connected to said first group of tubes so that at the end of a complete sequential cycle of operation of the multiplicand tubes a potential impulse is impressed upon the multiplier tubes to operate them a step in the sequence,

2. In combination a plurality oi gaseous electron tubes, each representing a denomination of a multiplier, so connected in a circuit that they are operable one at a time in sequence. in response to each oi commonly received electric impulses; and a second plurality oi gaseous electron tubes arranged in a chain, each plurality representing a denomination of a multiplicand, so connected in a circuit that conduction in one tube renders the next tube in the chain conducting, said group being connected to said first group of tubes so that at the end of a complete sequential cycle of operation of the multiplicand tubes, a potential impulse is impressed commonly upon the multiplier tubes to operate them a step in the sequence.

3. In combination a plurality of electron tubes each representing a digit of a multiplier so connected in a circuit that they are operable one at a time in sequence in response to each of commonly received electric impulses; a second plurality of electron tubes each representing a digit of a multiplicand so connected in a circuit that they are automatically rendered conductive in sequence and connected to said first group of tubes so that at the end of a cycle oi operation of the multiplicand tubes a Potential impulse is impressed upon the multiplier tubes; and an output circuit for each tube of the multiplier which circuit is given a rise in potential as the associated tube becomes conducting.

4. In combination a, plurality of electron tubes representing digits of a multiplier so connected in a circuit that they are operable one at a time insequenceinresponsetoeachotreceived electric impulses: a second plurality of electron tubes representing the digits of a multiplicand so connected in a circuit that they are automatically rendered conductive in sequence and connected to said nrst group of tubes so that at the end ot a cycle of operation 0! the multiplicand tubes a potential impulse is impressed upon the multiplier tubes; and means associated with each multiplicand tube which means is given an electric potential impulse when the associated tube becomes conductive.

5. In combination, a plurality oi gaseous electron tubes, each representing a digit oi a multiplier and connected in a circuit so they are operable one at a time in sequence, in response to each of commonly received electric impulses: means to render the first tube of the sequence operable; a second plurality oi! gaseous electron tubes, each representing a digit of a multiplicand, so connected in a circuit that they are automatically rendered operable in sequence and connected to said first group of tubes so that at the end of a cycle oi operation of the multiplicand tubes a potential impulse is impressed commonly upon the multiplier tubes; means to start the sequential operation of the multiplicand tubes; an output circuit for each tube of the multiplier tubes, each of which output circuits is given a rise in potential as the associated tubes become conducting; and an output circuit for each 01' the multiplicand tubes. each of which circuits is given a rise in potential as the associated multiplicand tube becomes conducting.

6. In combination, a plurality of gaseous electron tubes, each representing a digit oi a multiplier and so connected in a circuit that they are operable one at a time in sequence, in response to each of commonly received electric impulses; a second plurality of gaseous electron tubes, each representing a digit of a multiplicand and so connected in a circuit that they are automatically rendered conductive in sequence, and connected to said first group of tubes so that at the end of a cycle of operation 01' the multiplicand tubes a potential impulse is impressed commonly upon the multiplier tubes; an output circuit for each or the multiplier tubes, each oi which circuits is given a rise in potential as the associated tube becomes conducting; an output circuit for each of the multiplicand tubes. each of which circuits is given a rise in potential as the associated tube becomes conducting; and a means associated with each output circuit to connect said circuit with said tube and disconnect said circuit from said tube as selectively determined.

7. A first plurality of electron tubes each tube representing a digit 01' a multiplier; a second plurality of tubes each tube representing a digit of a multiplicand; means supplying operating energy to said tubes; means connecting the multiplicand tubes to cause said multiplicand tubes to automatically become conducting one at a time in sequence; means connecting the multiplier tubes to cause the multiplier tubes to become conducting one at a time in sequence; means coupling the first and second groups of tubes so that each step oi operation of the first group is caused by the completion of a cycle of sequential operation of said second group; output means for each of said tubes, said output means being given a rise in potential each time the associated tube becomes conducting; selective means to determine whether any of said output menu should be given said rise in potential or not as the associated tube becomesccnductlng; and a plurality or tubes connected in] groups. each group representing an output meansol the multiplier tubes by which the group is controlledand connectedin other groups each oi which'represents the output means of one of the multiplicanditubesr and connected in third groupings, each ot'whioh represents the Joint control of adigitrepr'esenting tube of the multiplier and a disitreprcsenting tube of the multlplicand whose productis represented in the same denomination. I

8. In combinationi-a' plurality oi electron tubes representing denominations of a multiplier so connected in a circuit that they are operable one at a time in sequence; iii-response to each of commonly received electric impulses; a second plurality of electron tubes representing the denominations 01' a multipli'cand so connected in a circuit that they are automatically rendered conducting in sequence, and connected to said first group of tubes, so that at the end or a cycle 01' operation of the multiplicand tubes a, potential impulse is impressed upon the multiplier tubes: a plurality of means each representative of a d'git, said means including a plurality of electron tubes equal in number to the number-oi denominations in the multiplier times the number of denominations in the multiplicand; and connections between the product representing tubes, a source of electric energy, and the multiplier and multiplicand tubes. whereby any one of said product tubes is renderedconductlng by reason of the multiplicand tube and multiplier tube whose prodnot it represents, being simultaneously in a con ducting condition.

9. In combination, a multiplier unit, including an electron tube for each of a plurality of denominations, based on the binary system of numerical notation; a multipllcand unit, including an electron tube for each oi'a plurality of denominations, based upon the binary system of numerical notation, and arecycling means; connections between the tubes of the multiplicand unit whereproduct of a multiplicand digit as multiplied by a multiplier by the tubes are caused to become conducting one at a time in sequence automatically, said sequential' o eration being automatically repeated by the recycling means; couplings between the multiplier' unit and the multiplicandunit; connections between the tubes 0! the multiplier whereby they are madeto become conducting one at a time in sequence, each step of the sequential operation being caused through said couplings by the completion or asequential cycle of the multiplicand operation; and means under control of the multiplier unit for causing the multiplicand unit recycling'means' to cease its repcat opera-j V tions at the. conclusion "or one sequentialcycle of operational the'multiplier unit. r

10. In combinatiomna multiplier unitincluding anelectrohiiibc' ler each of a plurality of denominationsxbased on the binary system of numerical notation: a multiplicand unit including an electron tube for each of a pluralityoi denominations based upon the binary system of numerical notation, and a recycling means: connections between the tubes of the multipllcand unit whereby the tubes are caused to become conducting one at a tlmein sequence, said sequential operation being automatically repeatedby the recycling means; couplings between the multiplier unit and the multipllcand unit; connections between the tubes 01' the multiplier unit whereby they are made to become conducting one at a time in sequence, each step of the sequential operation being caused through said couplings by the recycling means or the multipllcand unit on the completion of a cycle of said multlplicand unit; means under control or the multiplier unit for causing the multiplicand unit recycling means to cease its operation at the conclusion oi one sequential cycle of operation or the multiplier unit; an output conductor for each tube oi the multipller unit which output conductor is connected to an electrode of the associated tubes so as to receive an electric potential rise as such tube is operated; an output conductor for each tube of i the multiplicand unit so connected to an electrode 01 the associated tube that such tube is given an electric potential rise as the associated tube is operated; controls whereby to start the operation of the multiplier units and the multiplicand units: a plurality of responsive means. each of which is associated with an output conductor of the muleach associated with one or more or the responsive means. which conductors are given an electric potential change nearly one of the responsive means with which they are associated responds.

11. In combination, a multiplier unit, including an electron tube for each 01' a plurality of denominations based on the binary system of numerical notation; a multiplicand unit including an electron tube for each of a plurality of denominations based on the binary system of numerical notation, and a cycling means; connections between the tubes 01 the multipllcand unit whereby the tubes are caused to become conducting one at a time in sequence, said sequential operation being automatically repeated by the recycling means; couplings between the multiplier unit and the multlplicand unit; connections betweenthe tubes of the multiplier unit whereby they are made to become conducting one at a time in sequence, each step of the sequential operation being caused through said couplings by the recycling means upon completion of the sequential cycle of operation oi the multiplicand unit means under control oi the multiplier unit operated; an output conductor for each tube 01" the multiplicand unit so connected to an electrode oi the associated tube that each conductor is given a change in electric potential as the associated tube is operated: a plurality of means, each of which is associated with a conductor oi the multiplier unit and one or the conductors of the multiplicand unit so as to respond when the associated conductors receive their potential change at the same tim a plurality of conductors each associated with one or more of the responsive means and each having a designated numerical value. which conductors are given an electric potential impulse as any one oi the responsive means with which they are associated and an accumulator of data havin denominational orders based upon the binary system of numerical notation. which is actuated by the changes of potential the conductors associated with the responsive means, said conductors and the denominational orders of the accumulator being so connected that the accumulator is actuated to have data entered therein corresponding to the product represented by multiplying the value oi the multiplicand tubes by the value of the multiplier tubes.

12. In combination, a multiplier unit, including an electron tube for each of a plurality oi. denominations based on the binary system or numerical notation; a multiplicand unit including an electron tube for each of a plurality of denominations based on the binary system oi numerical notation and a recycling means; conneetions between the tubes 01 the multiplicand unit whereby the tubes are caused to become conducting one at a time in sequence. said sequential operation being automatically repeated by the recycling means; couplings between the multiplier unit and the multiplicand unit; connections between the tubes of the multiplier unit whereby they are made to become conducting one at a time in sequence, each step of the sequential operation being caused through the couplings by the recycling means upon completion of the sequential cycle oi operation of the multiplicand unit; means under control 01' the multiplier unit for causing the multiplicand unit to cease its repeat operation at the conclusion of one sequential cycle or operation of the multiplier unit; controls whereby to start the operation of the multiplier unit and the multiplicand unit; an output conductor for each tube of the multiplier unit, which output conductor is connected to an electrode of the associated tube so as to receive a change in electric potential as each tube is operated: an putput conductor for each tube of the multiplicand unit so connected to an electrode oi. the associated tube that each conductor is given a change in electric potential as the associa tube is operated; a plurality of means, each oi which is associated with a conductor of the multiplier unit and one of the conductors of the multiplicand unit so as to respond when the associated conductors receive their potential change at the same time; a plurality of conductors each associated with one or more of the responsive means and each having a designated numerical value, which conductors are given an electric potential impulse as any one oi the responsive means with which they are associated responds; an accumulator of data having denominational orders based upon the binary system of numerical notation, which is actuated by the changes of potential of the conductors associated with the responsive means, said conductors and the denominational orders oi the accumulator being so connected that the accumulator is actuated to have data entered therein corresponding to the product represented by multiplying the value of the multiplicand tubes by the value of the multiplier tubes; and manipulative means to select which 01' the multiplicand tubes and which of the multiplier tubes when operative shall impress a potential change upon the associated responsive means.

13. In combination a plurality of electron tubes each representing a digit: connections between the tubes whereby they may be made conducting one at a time in sequence, each step oi the sequence being in response to an electric impulse commonly impressed upon all the tubes; 9. second plurality of electron tubes divided into groups, each group being associated with one of the tubes at the iirst named plurality; means common to the tubes of a group normally rendering the tubes inoperative; and connections between a tube oi the first plurality and associated group whereby when said tube of the first plurality i; operated it prepares for operation all the tubes 0! the group with which it is associated.

14. In combination, a product accumulator actuable by electric impulses; a multiplier unit including a plurality oi electron discharge tubes. each of said tubes representing a denomination in the binary system oi numerical notation; a. multiplicand unit including a plurality oi electron discharge tubes, each oi said tubes representing a denomination in the binary system of numerical notation; a plurality oi. means for entering data into the several denominations of the accumulator; a plurality of electron tubes, each of which produces an electric impulse when actuated by operation 0! a tube of the multiplier unit in conjunction with the operation of a tube 0! the multiplicand unit at the same time; and means connecting one or more oi the electric im pulse producing tubes to an associated one of the data entering means so that when one of the tubes associated with the data entering means is caused to produce an impulse by reason of the associated multiplier and multiplicand tubes being actuated, data is entered into the proper denomination of the accumulator to represent the product of the value of said multiplicand tube asbemultiplied by the value of said multiplier tu 15. In combination, an accumulator of data having denominational orders based on the binary numerical notation; a plurality oi electron tubes equal in number to the number of denominations in a multiplier as multiplied by the number or denominations in a, multiplicand; a multiplier unit based upon the binary system of numerical notation, said unit including a gaseous electron tube for each denomination oi the multiplier, including means connecting the tubes 50 they may be caused to operate in sequence in response to commonly received electric impulses, including an output conductor for each tube having impressed thereon electric potential changes as the associated tube is rendered conducting, said output conductcrs having selectin means included therein to connect or disconnect the conductor with or from the associated tube; a multiplicand unit, including a plurality of electron discharge tubes connected so they are operated one at a time in sequence automatically, said multiplicand unit including an output conductor for each tube, which is impressed with an electric potential change as the associated tube is operated, including selective means whereby each output conductor may be connected with or disconnected from said associated multiplicand tube so as to determine whether a potential change shall be produced on said conductor, means to cause the sequence of operation to be repeated, said means also causing a. step of operation or the multiplier unit, and means controlled by completion of operation of the multiplier unit Ior disabling the repeating means of the multiplicand unit; and means for operating the tubes of the first mentioned plurality of tubes under joint control oi the combined output means of the multiplier unit and the multiplicand unit so as to operate a. selected one of said tubes 2,404,001 19 20 whsnacsstainonsoithemultiplicsndunitoutlatorotnumerlcaldatabasedonthebinarysysputconduetorsrccsivesapotentialchango at temcd'notatiomactuatedbyelectricimpulsesinthssamstimsaccrtainoneotthsoutputoom troduced intotheseveraldenominationsznndoctors of the multiplier lmit receives a potenpulsemeans tor actuating the accu-, tialchangatheoperatedtubeoitheiilstplumulatonincludingapluraiityorelectrcntubes rality having an output conductor leading to the equal in number to the number of denominapmpcr denomination oi the accumulator-so as to tions or a multiplier times the number or deenter therein the product data represented by nominations of a multiplicand, each oi said tubes multiplying the value or the lssociated multipiibeing supplied with operating energy and concandtuhsbythevalueor themultinectedsoastosupplyanimpulsetothepr per plier tube. denomination oi the accumulator when acted up- 16. In combination, an accumulator ot numeron coniointiy by a digit-representing device or ical data based on the binary system oi numerthe multiplier and a digit-representing device icai notation, including denominational maps of of the multiplies-ml whose product such tube repeiectron tubes. the tubes representing the digits resents; an electronic multiplier unit based on in the denomination, said accumulator being acthe binary system oi numerical notation, includtuated by electric potential hances introduced ing a tube for each denominational order oi the thereto by d orders or between demultiplier; a multiplicand unit based on the biorders; data introducing means nary system or numerical notation, there being 0! a plurality of electrical cond ctors an electron tube for each denomination of the each representing a denomination of the acc multiplicand; connections between the multim lfl r to the prod ct 0! a lsi plier tubes and the impulse-producing tubes: or a multiden minatiimal num er m mlfller by connections between the multiplicand tubes and a disit of a m tiden ina o ei 1m multlthe impulse-producing tubes; and connections pncand; and m ns to app y a Potential v between the multiplier tubes and the multiplition to y su c n or y s s co te cand tubes whereby each tube or the multiplier thereto an electrode or a thyratron onnect d in unit is rendered conductin in conjunction with a 8811 fl m s m- 1i 119M118 each tube in the multiplioand unit to control the d moted numerical value or the dcnominacorresponding tube of the impulse-producer. tion of the accumulator represented by the con- 20. In combination, a denominational accud flr: n e l l 8 representing mulator of numerical data based on the binary mul ilfllcr selecting means and denominational system of notation, actuated by electric impulses 6181b M M 8 multipliclmd Selecting means introduced into the denominations; impulse proto comm] 51d m t selectively whereby ducing means for actuating the accumulator, in- 6 m "P 8 the Product 0! the eluding a plurality of electron tubes equal in selected multiplier n m y 8 Selected nurnber to the number of denominations of a 91mm number are caused to bemme active in multiplier times the number of denominations oi denomlnaliional Beqlleme. t1m8 giving. the input a multiplicand, each oi said tubes being supconductors a potential change to enter product plied with operating energy and connected so dam into the Wawras to supply an impulse to the proper denominan 60111793181301! plurality of electmmc tion of the accumulator when acted upon conrelays ha 119818111111 Product Values. 831d jointly by a digit-representing device of the mul- 1535 being selectively mntmned Jointly by tlplier and a digit-representing device of the D unit and a mumpnmd each unit multlplicand. whose product such tube repre- B divided mm denmnmaflonseach may sents; an electronic multiplier unit, based on the 1115 Emma-ted with one denomination in each binary system 01 numerical notation, including a means to issue mammal Variations tube for each denominational order of the multhe multiplicmd demmmamn by denomj tiplier; a multiplicand unit based on the binary nation and to Impress them upon the associated system of numerical notation, including an elecones of the relay devices to control them; means "on tube for each denomination of the m to issue potential Variation? from the multiplier cal-id; connections between the multiplier tubes dencmmauon by demmmatmn and impress and the impulse-producing tubes; connections them upon the associated ones Of the relay between the multiplicand tubes and the impulse vices, said multipiicand unit and multiplier unit producing tubes; connections between the mul- Pimmtial variations being timed act hint]? at tiplier tubes and the multiplicand tubes wherediscretc periods to render the associated prod by each tube in the multiplier unit is rendered i m f g z eflecflve to represent the conducting in conjunction with each tube in the a e P multiplicand unit to conjointly affect the cor- In multiplying device wherein the responding tube in the impulse-producer; and mention is performed in stages each under means for selecting which digit tubes of the mulcontml M demmmatmn of a multiplierthe tiplier unit and the multiplicand unit shall act combination of a plurality of groups of self-recnjolnfly Setting 816cm" discharge tube 1518, each 21. In combination, a multiplier unit, includ- P representing a stage multiplication and ins a gaseous electron discharge tube for each each tube in the group representing a denomination of a. multiplier based on the binary nomination the multiplicandi conductor system of numerical notation, each of said tubes controlling each Bmup controlled by a multiplier including an anode, a cathode, and a control unit; a multiplicand unit and including a electrode: means supplying operating energy to ductoi for each denomination of the each of said tubes: means for applying a nomal- 5nd. w i h cenducmlfl are coupled Jointly with ly controlling potential on said control grids; the conductors from the multiplier 5 the elecmeans to connect the tubes so they are rendered tron tubes for determining which oi the relay conducting one at a time in sequence in response tubes shall come cfln iv to represent P to electric impulses commonly received by all but not data. the first tube applied to the control grids, the 19. In combination. a denomination m T conductivity oi a preceding tube of the sequence priming the grid of the succeeding tube of the sequence so as to be responsive to the next impulse; means to cause conduction in the first tube of the sequence; means including a resistance in the cathode supply circuit for each tube for causing a potential rise in the cathode as a tube becomes conducting; means connected to said cathodes of all but the last tube receiving an electric impulse each time the associated tube is rendered conducting; a multiplicand unit, including a plurality of electron discharge tubes. each representing a denomination in the binary system of numerical notation, each of said tubes including an anode, a cathode and a control grid; means for applying operating energy to the anode-cathode circuits of said tube; means to apply a normally controlling bias to the grid of said tubes to prevent conduction therein; means connecting the tubes so they are caused to become conducting one at a time in sequence automatically; means to start conduction in the first tube of the sequence; means to recycle the multiplicand tubes so they may be caused to automatically repeat their operation in sequence, said recycling means impressing an impulse upon grids of all but the first of the tubes oi the multiplier unit to cause a step of operation therein; means rendered efiective at the completion of the sequential operation of the multiplier tubes to render the recycling means of the multiplicand tubes ineffective; means including a resistor in the cathode supply of each tube of the multiplier unit to cause a potential rise in the cathode as the tube becomes conductiim; an output conductor connected with the cathode of each tube of the multiplicand unit except the last; a plurality of selfextinguishing gaseous triode electron discharge tubes, each of said self-extinguishing tubes representing the product oi one of the digits of the multiplier by one of the digits of the multiplicand, and said number of sell-extinguishing tubes equalling the product of the number of multiplier denominations by the number of multiplicand denominations; means normally supplying a controlling potential bias to said seliextinguishing tubes toprevent conduction there- -nary numerical accumulator, all

in; means connecting the output conductor for each denomination of the multiplier with the sell-extinguishing tubes whose designated product includes that digit of the multiplier as a. factor, whereby when said multiplier tube is in a conducting condition, the controlling bias upon the control grids of those corresponding sell-extinguishing tubes is reduced; means connecting the output conductors of the multiplicand unit to those sell-extinguishing tubes whose designated product includes that digit as a factor to give said tubes an impulse whereby to destroy the controlling bias on any associated tube which has had its potential reduced by connection to a conducting multiplier tube; a plurality of conductors, each representing a denomination of a biot the self-extinguishing tubes whose value is the value of the conductor being connected thereto and delivering thereto an electric impulse upon the discharge of any of said connected self-extinguishing tubes; an electronic product accumulator of numerical data based on the binary system of numerical notation, each denomination oi which includes two electron discharge tubes connected for alternate operation so that an electric impulse impressed commonly thereon will cause the tube of the denomination to become extinguished and the non-conducting tube of the denomination to become conducting; means connecting each conductor from the self-extinguishing tubes to the corresponding denomination tubes of the product accumulator so that when any impulse is received by said conductor it will change the mode of operation of the corresponding denominational tubes; and means interconnecting the denominations oi the accumulator whereby when the denomination having had entered therein its full capacity of data receives another impulse from the associated selfextingulshing tubes, the denomination will 'return to zero and in so doing impresses an impulse on the next higher denomination so as to enter therein a unit of data.

' JOSEPH R. DESCH.

ROBERT E.

Certificate of Correction JOSEPH R. .DESCH, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 16, line 38, claim 11, for the word cycling read recycling; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 22nd day of October, A. D. 1946.

Patent No. 2,404,697. July 23, 1946.

LESLIE FRAZER,

First Assistant Uommimomr of Patents.

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