US1892634A - Calculating device - Google Patents
Calculating device Download PDFInfo
- Publication number
- US1892634A US1892634A US1892634DA US1892634A US 1892634 A US1892634 A US 1892634A US 1892634D A US1892634D A US 1892634DA US 1892634 A US1892634 A US 1892634A
- Authority
- US
- United States
- Prior art keywords
- windows
- multiplicand
- indicia
- product
- strips
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000463 material Substances 0.000 description 8
- 238000010276 construction Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 102000007469 Actins Human genes 0.000 description 2
- 108010085238 Actins Proteins 0.000 description 2
- 241000270299 Boa Species 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06G—ANALOGUE COMPUTERS
- G06G1/00—Hand manipulated computing devices
- G06G1/02—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales
- G06G1/04—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by construction
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06G—ANALOGUE COMPUTERS
- G06G1/00—Hand manipulated computing devices
- G06G1/02—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales
- G06G1/04—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by construction
- G06G1/045—Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by construction with scales borne by bands
Definitions
- This invention relates to calculating devices, and more particularly to a computlng tablet :in the nature of a mechanical multiply -ing device wherein'movable indiciamembers are employed to disclose, at a glance, the product obtained by multiplying any des red 1 number by another number.
- the primary Object of the invention is to provide a device by which the user is enabled to reduce the process of multiplication to the "si mple'addition of numbers, or rows of numbers and so to considerably facilitate the "wholeoperation. v I
- F gure 1 is a perspective viewot the device
- Figure 2 is a top plan View of the obverse side of the device;
- I r Figure 31s a top plan v ew of the reverse sideof the device when turned end for end;
- Figure 5 is a'reverse view of the indicia I strip shown in Figure 4,when turned endifor end with respect to Fig. 4;
- Figure 6 is a partial vertical sectional view on the line 66;0f Figure 2, looking in the direction ofthe arrows; p
- Figure 7 is a partial vertical sectional view on the 'l'ine77 of Figure 2, looking in the direction of the arrows;
- These multipllcand selector openings may to downward.
- the multiplication tablet shown in this instance includes a casing A, which may be conveniently formed to include upper and lower covers B and C, respectively, separated at the top and bothside edges by a suitable spacer D.
- the covers B and C may desirably be formed of relatively and durable card material, such, for instance, as fibreboard,or heavy cardboard or other material;
- v w ll1e jacket or casing A thusconsists of a hollow body, open at the bottom; and-suitablem-eans are employed to form a plurality of parallel, vertical guide slots E within the hollow body, as for instance; by providing a plurality ofspa cer strips F these strips F also serving to hold the covers B and C together so that the tablet A, even though formed of relatively thin material will never-
- multiplicand 1nd1cia H which consist of vertical rows of numerals from 1- to 9.v inclusive, ar-
- the cover C also has a horizontalrow of multiplicand sight apertures M which correspond to the apertures J and are also designated by the numeral 1.
- the numeral 1 applied to the apertures J and M is to indicate the product obtained by multiplying a multiplicand by the multiplier 1; and the numeral designations 2 and 9 inclusive are multipliers, all as will be hereinafter more conveniently explained.
- the vertical multiplicand selector openings G having the multiplicand indicia H, indicate, reading from right to left, units, tens, hundreds, thousands, etc.; and means are provided whereby to indicate, at one or the other of the horizontal rows of sight windows K, the product obtained by multiplying any desired number selected from the vertical rows of multiplicand indicia- H by the multiplier associated with the rows of sight windows K which displays the resultant product.
- each of the vertical slots E a slidable fiat indicia strip Q, the obverse side R of which is seen in Fig. l, and the reverse side S in Fig. 5.
- Each of the indicia strips Q has on its obverse side R, a group of numerals T, which correspond to the numerals H which represent the multiplicand indicia, the numerals T being arranged in the same order as the numerals H.
- These numerals T are located in vertical alignment with the multiplicand sight apertures J and are hence normally invisible, except when brought into use whereupon the numerals T are adapted to be selectively displayed at the multiplicand sight openings J.
- each strip is provided with a group of numerals U which correspond to the numerals T and are adapted to be displayed at the sight apertures M, the latter being for convenience when using the reverse side of the tablet in connection with the multipliers 6 to 9 inclusive.
- Each of the indicia strips is similarly constructed on both faces R and S with additional groups of product indicia W which are successivel arranged in correspondence with the mu tipliers 2, 3, 4, et seq., in accordance with arithmetical calculation, to indicate at the product sight windows K and L (and/0r P or O) the product obtained by multiplication of a selected multiplicand by one or the other of the multipliers numbered from 2 to 9 inclusive.
- These latter groups of product indicia are arranged in two vertical colunms, one column Wa indicating, in the units strip Q, units, and the other column Wb indicating, in the same strip, tens as derived from the multi lying operation.
- the co umns Wa are adapted to be displayed at the vertically ali ed product sight apertures P which, as a ready stated, are one-half the size of the product sight apertures K; and the columns Wb are ada ted to be displayed at the right hand side of the vertically aligned product sight apertures K.
- Adjacent strips Q representing tens, hundreds, etc., at their respective multiplicand indicia. T, are adapted to dis lay the columns Va at the right hand side 0 the appropriate apertures K, and the columns ⁇ Vb at the left hand side of said apertures K.
- the numerals Wa are displayable at the left hand side of the appropriate apertures K and the numerals Wb, at
- the strips Q lie in inoperative position so that no indicia are visible throu h the apertures J, K, O, P, L or M, the on y indicia. visible being the multiplicand indicia H on the cover 13.
- Means are rovided to move the strips Q to display at t e sight a ertures J, KOP M and IrO-P', t e product obtainable by multiplying any desired number, the digits of which have been selected from one or more of the multiplicand indicia H, by either of the multipliers designated 1 to 9 inclusive.
- each of the strips Q is provided with a suitable mark, as for instance a small hole X opposite each of the multiplicand indicia numerals T, these holes X being accessible at the vertical openings G.
- a suitable pin or pointer Z is successively inserted in the hole opposite the digit H desired to be selected from the multiplicand indicia, and the pin is ushed downward to the bottom of the opening G, in each case, the bottom of the opening G actin as a limiting stop.
- the vertical groups '0 numerals T and W are so arranged that appropriate multiples of the multiplicand indicia H will be then displayed at the several rows of product sight openings opposite the multipliers humbered from 1 to 9, inclusive.
- Multiplier Product indicia Product in which certain of the digits appearing at one window K, when added together, exceed 9 so as to requiretwo digits to express the result.
- the tens digit so far as the indicia appearing at each of the said windows K are concerned, is added to the product total of the digit or digits appearing at the next window K to the left, with the results as indicated in the table immediately above.
- the same procedure is ob served regardless of the number of digits in the multiplicand.
- the device is equally adapted for use with any multiplier having a plurality of digits. For instance, if the multiplicand 752 is to be multiplied by 864,
- any desired spacing means may be employed to define the slots B, such for instance as by inserting wire staples or the like, in vertical rows, through the covers B and C; but the spacers F as shown provide a smooth running arrangement for the strips Q by positively defining the slots E.
- a calculating device comprising a tablet formed with parallel guide slots and having windows in its face, the windows being arranged in parallel spaced rows, the uppermost row of windows being narrow and communicating each with one guide slot, the remaining rows of windows having the terminal windows thereof of the same Width as the first said windows and communicating with the outermost guide slots, the interme' diate windows in the remaining rows being double the width of the first said members and communicating each with two adjacent guide slots, and numeral'bearing strips inserted in the guide slots. and having the nu-- merals thereof arranged at opposite longitudinal edges, and indicating means to permit adjustment of the strips in the guide slots according to a number to be multiplied, the
- a calculating device comprising a tablet formed with parallel guide slots and having windows in its face, the windows being arranged in parallel spaced rows, the upper" plicand,
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Mathematical Physics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Complex Calculations (AREA)
Description
Dec. 27, 1932. RUBINSKY CALCULATING DEVICE Filed Dec. 15, 1930 2 Sheets-Sheet INVENTOR ATTORNEY IIIIIIIII 'IIIIIIIIII WITNESS:
Dec. 27, 1932.
l. RUBINSKY CALCULATING DEVICE Filed Dec. 15, 1930 2 Sheets-Sheet 2 a 5 ll [WIN Rummy/{r INVENTOR ATTORNEY Patented Dec. 27, 1932 "PATENT OFFICE IVAN nunmsxzon BEIRUT, SYRIA I CALCULATING DEVICE Application filed-December 15, 1930, Serial No. 502,506, and in Syria January 20, 1930;
This invention relates to calculating devices, and more particularly to a computlng tablet :in the nature of a mechanical multiply -ing device wherein'movable indiciamembers are employed to disclose, at a glance, the product obtained by multiplying any des red 1 number by another number. p r
' The primary Object of the invention is to provide a device by which the user is enabled to reduce the process of multiplication to the "si mple'addition of numbers, or rows of numbers and so to considerably facilitate the "wholeoperation. v I
' Other objects are to simplify and improve the "construction of multiplying or calculating' devices generally and to reducethe cost of manufacture thereof, so that amultiply-i sing device may be manufactured at low cost and bethereb-y economically availed'of by fthe public. r
Other objects andadvantages of the invenit ti'onwillbe hereinafter specifically pointed out, or will become apparent, as the specificationproceeds. a
' With'theabove'indicated objects in view,
the :invention resides in certain novel constructions and comb nations and arrangement bf parts, clearly described inthe following specification and fully illustrated in the ac- 'companying drawings, which latter show embodiments 'ofthe invention as at present pre 'ferred.
In the drawings:
" Figure 2 is a top plan View of the obverse side of the device; I r "Figure 31s a top plan v ew of the reverse sideof the device when turned end for end; 'Flgure 4 15311 obverse view of one ofthe indicia strips Figure 5 is a'reverse view of the indicia I strip shown in Figure 4,when turned endifor end with respect to Fig. 4;
Figure 6 is a partial vertical sectional view on the line 66;0f Figure 2, looking in the direction ofthe arrows; p
Figure 7 is a partial vertical sectional view on the 'l'ine77 of Figure 2, looking in the direction of the arrows;
"' Fi'gure- 8 is a partialtransverse sectional theles's boa substantially-rigid unit.
termed These multipllcand selector openings may to downward.
View on the line 8-8 of Figure 2, looking in the direction of the'arrows' v i igi1r'( 9=is a view similar to Figure 8, taken on the line 99 of'Figure 2, and h Figure 10 is an elevation of a suitable w pointer.
Referring more particularly to the drawings, the multiplication tablet shown in this instance-includes a casing A, which may be conveniently formed to include upper and lower covers B and C, respectively, separated at the top and bothside edges by a suitable spacer D. The covers B and C may desirably be formed of relatively and durable card material, such, for instance, as fibreboard,or heavy cardboard or other material;
and the spacerID may consist of strips of cardboard or other material, or the same may beof one piece, in square U-shape. v w ll1e jacket or casing A thusconsists of a hollow body, open at the bottom; and-suitablem-eans are employed to form a plurality of parallel, vertical guide slots E within the hollow body, as for instance; by providing a plurality ofspa cer strips F these strips F also serving to hold the covers B and C together so that the tablet A, even though formed of relatively thin material will never- The cover B-includesa plurality of elongated 'parallel vertical openings G, here multiplicand selector openings.
be laid out'in any desired plurality; and alongside each opening G I arrange multiplicand 1nd1cia H which consist of vertical rows of numerals from 1- to 9.v inclusive, ar-
which represent the multiplier. There may be any desired number of rows of windows K in the cover B, but to reduce the size of the tablet and increase its capacity, I provide in the back cover G. additional horizontal rows of product sight windows L, here having numeral designations, 6, 7, 8 and 9 representing additional multipliers. The product sight windows K which are designated by the multipliers 2, 3 and 4 are in registration with the product sight windows L which are designated by the multipliers 6, 7 and 8.
The cover C also has a horizontalrow of multiplicand sight apertures M which correspond to the apertures J and are also designated by the numeral 1.
In both instances, the numeral 1 applied to the apertures J and M is to indicate the product obtained by multiplying a multiplicand by the multiplier 1; and the numeral designations 2 and 9 inclusive are multipliers, all as will be hereinafter more conveniently explained.
It will also be seen that the product sight apertures O and P, at each end of each horizontal row, is one half the size of the intervening apertures L and K, the reason for which will also later appear.
The vertical multiplicand selector openings G, having the multiplicand indicia H, indicate, reading from right to left, units, tens, hundreds, thousands, etc.; and means are provided whereby to indicate, at one or the other of the horizontal rows of sight windows K, the product obtained by multiplying any desired number selected from the vertical rows of multiplicand indicia- H by the multiplier associated with the rows of sight windows K which displays the resultant product.
In this instance I provide in each of the vertical slots E, a slidable fiat indicia strip Q, the obverse side R of which is seen in Fig. l, and the reverse side S in Fig. 5. Each of the indicia strips Q has on its obverse side R, a group of numerals T, which correspond to the numerals H which represent the multiplicand indicia, the numerals T being arranged in the same order as the numerals H. These numerals T are located in vertical alignment with the multiplicand sight apertures J and are hence normally invisible, except when brought into use whereupon the numerals T are adapted to be selectively displayed at the multiplicand sight openings J. The reverse side S of each strip is provided with a group of numerals U which correspond to the numerals T and are adapted to be displayed at the sight apertures M, the latter being for convenience when using the reverse side of the tablet in connection with the multipliers 6 to 9 inclusive.
Each of the indicia strips is similarly constructed on both faces R and S with additional groups of product indicia W which are successivel arranged in correspondence with the mu tipliers 2, 3, 4, et seq., in accordance with arithmetical calculation, to indicate at the product sight windows K and L (and/0r P or O) the product obtained by multiplication of a selected multiplicand by one or the other of the multipliers numbered from 2 to 9 inclusive. These latter groups of product indicia are arranged in two vertical colunms, one column Wa indicating, in the units strip Q, units, and the other column Wb indicating, in the same strip, tens as derived from the multi lying operation. In the units strip Q the co umns Wa are adapted to be displayed at the vertically ali ed product sight apertures P which, as a ready stated, are one-half the size of the product sight apertures K; and the columns Wb are ada ted to be displayed at the right hand side of the vertically aligned product sight apertures K. Adjacent strips Q, representing tens, hundreds, etc., at their respective multiplicand indicia. T, are adapted to dis lay the columns Va at the right hand side 0 the appropriate apertures K, and the columns \Vb at the left hand side of said apertures K. In the extreme left hand strip Q the numerals Wa are displayable at the left hand side of the appropriate apertures K and the numerals Wb, at
the apertures 0. It is clear from the above I that the apertures K overlap two adjacent stri s Q.
N brmally the strips Q lie in inoperative position so that no indicia are visible throu h the apertures J, K, O, P, L or M, the on y indicia. visible being the multiplicand indicia H on the cover 13. Means are rovided to move the strips Q to display at t e sight a ertures J, KOP M and IrO-P', t e product obtainable by multiplying any desired number, the digits of which have been selected from one or more of the multiplicand indicia H, by either of the multipliers designated 1 to 9 inclusive. In this instance each of the strips Q is provided with a suitable mark, as for instance a small hole X opposite each of the multiplicand indicia numerals T, these holes X being accessible at the vertical openings G. A suitable pin or pointer Z is successively inserted in the hole opposite the digit H desired to be selected from the multiplicand indicia, and the pin is ushed downward to the bottom of the opening G, in each case, the bottom of the opening G actin as a limiting stop. The vertical groups '0 numerals T and W are so arranged that appropriate multiples of the multiplicand indicia H will be then displayed at the several rows of product sight openings opposite the multipliers humbered from 1 to 9, inclusive.
Thus, when it is desired to obtain the product by multiplying the multiplicand 111 by either of the multipliers, the three right hand strips designed for units, tens and hundreds are set, by means of the pin or pointer'Z, to
,ever two digits (W?) and Via) appear at the 1: manages i 5X3 indicate 11 1 at the apertures J p and M, by moving each of the strips Q one step downward. The result at the different rows ofv p v zWe then takef t-he productiopposite the '-"]ten s of the multiplier, which is 6, and-enter [the same in properrelative tens position "flieneaththe number'3008, asfollows":
multipliers will be as follows:
Product Multiplier A more practical illustrative example is shown in the drawings, however, whereinthe QQOO IGDUIPPO NDH multiplicand selected for illustration is 752. The result is seen somewhat differently in.
this instance, whenever the multiplier is greater than 1. For instance (and this IS an important feature of the construction) wheni same window K, as in connection with the 1 multiplier 2, wherein we find the result to be -14l04, the two digits appearing in the same window K are added together, so that the result, using the multiplicant 752 and the multiplier 2, is read l-504 or 1504. Similarly, for other multipliers, we see:
Multiplier Product indicia Product It will be seen that in connection with the multipliers 4 and 7 and 8 we obtain product indicia in which certain of the digits appearing at one window K, when added together, exceed 9 so as to requiretwo digits to express the result. In this case the tens digit, so far as the indicia appearing at each of the said windows K are concerned, is added to the product total of the digit or digits appearing at the next window K to the left, with the results as indicated in the table immediately above. The same procedure is ob served regardless of the number of digits in the multiplicand.
Now, as a further development in the usev of the apparatus, it is to be understood that while the device as shown and thus far described is equipped to utilize any desired multiplicand having up to eight digits, and
multipliers from 1 to 9, the device is equally adapted for use with any multiplier having a plurality of digits. For instance, if the multiplicand 752 is to be multiplied by 864,
we first select the product opposite the units of the multiplier, which is 4, and
write tlrexsame m a; memorandum slipms ,'S imilar-ly," we 'now select the product opposite the :"hundreds Qof thefmultiplier, I which is 8, and enter ithe number. in its fhu'ndr eds :position, beneath the other fig- 1 ures,-so{that the resultappearswas:
-- -"The"result'649728 is obtainedbyaddingthe three groups. 'Tli'ere is thus -practically no limit to the cap'acityof thedevice to multiply ys i 'iltiplicand fbyany desired: multiplier, accurately,-"conveniently and rapidly.
To re-set the device for a new multi it is simply necessary to hold the device vertically and press it down upon any flat surface so that all the strips Q, pass entirely into their respective slots E.
It is to be understood that instead of providing spacer strips as shown at F", any desired spacing means may be employed to define the slots B, such for instance as by inserting wire staples or the like, in vertical rows, through the covers B and C; but the spacers F as shown provide a smooth running arrangement for the strips Q by positively defining the slots E.
lVhat is claimed is: 1. A calculating device comprising a tablet formed with parallel guide slots and having windows in its face, the windows being arranged in parallel spaced rows, the uppermost row of windows being narrow and communicating each with one guide slot, the remaining rows of windows having the terminal windows thereof of the same Width as the first said windows and communicating with the outermost guide slots, the interme' diate windows in the remaining rows being double the width of the first said members and communicating each with two adjacent guide slots, and numeral'bearing strips inserted in the guide slots. and having the nu-- merals thereof arranged at opposite longitudinal edges, and indicating means to permit adjustment of the strips in the guide slots according to a number to be multiplied, the
rows of windows bearing digit indications of the multiplier. I 1 2. A calculating device comprising a tablet formed with parallel guide slots and having windows in its face, the windows being arranged in parallel spaced rows, the upper" plicand,
most row of windows being narrow and communicating each with one guide slot, the remaining rows of windows iaving the terminal windows thereof of the same width as 5 the first said windows and communicating with the outermost guide slots, the intermediate windows in the remaining rows being double the width of the first said members and communicating each with'two adjacent guide slots, and numeral bearing strips inserted in the guide slots and having the numerals thereof arranged at opposite longitudinal edges, and indicating means to permit adjustment of the strips in the guide 0 slots according to a number to be multiplied, the rows of windows bearing digit indications of the multiplier, the strip adjusting means consisting of slots com-munlcatin with the guide slots and opening onto the ace of the tablet, the latter havin the digits arranged in consecutive order side said slots, and the numeral bearing strips being formed a with pointerv receiving perforations spaced according to the numerals on said stri s. In testimony whereof I hereby a x my signature.
IVAN RUBINSKY.
Publications (1)
Publication Number | Publication Date |
---|---|
US1892634A true US1892634A (en) | 1932-12-27 |
Family
ID=3424879
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US1892634D Expired - Lifetime US1892634A (en) | Calculating device |
Country Status (1)
Country | Link |
---|---|
US (1) | US1892634A (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2477785A (en) * | 1946-03-04 | 1949-08-02 | James A Brown | Interest calculator |
US2494609A (en) * | 1946-06-13 | 1950-01-17 | Dalboni Carlo | Calculator |
US2610792A (en) * | 1949-11-07 | 1952-09-16 | Leo T Kaufman | Score indicator for boxing and the like |
US3115115A (en) * | 1960-10-07 | 1963-12-24 | Lang | Race handicap indicator |
US3916161A (en) * | 1974-03-12 | 1975-10-28 | Us Army | Hexidecimal to binary conversion device |
US4410797A (en) * | 1979-12-06 | 1983-10-18 | Otfried Hatzold | Calculation table for family planning |
US4798940A (en) * | 1986-08-19 | 1989-01-17 | Gaetano Salvo | Manual calculator for analog and digital numbers |
US4994656A (en) * | 1988-11-14 | 1991-02-19 | Ng Wang C | Logic design slide rule |
-
0
- US US1892634D patent/US1892634A/en not_active Expired - Lifetime
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2477785A (en) * | 1946-03-04 | 1949-08-02 | James A Brown | Interest calculator |
US2494609A (en) * | 1946-06-13 | 1950-01-17 | Dalboni Carlo | Calculator |
US2610792A (en) * | 1949-11-07 | 1952-09-16 | Leo T Kaufman | Score indicator for boxing and the like |
US3115115A (en) * | 1960-10-07 | 1963-12-24 | Lang | Race handicap indicator |
US3916161A (en) * | 1974-03-12 | 1975-10-28 | Us Army | Hexidecimal to binary conversion device |
US4410797A (en) * | 1979-12-06 | 1983-10-18 | Otfried Hatzold | Calculation table for family planning |
US4798940A (en) * | 1986-08-19 | 1989-01-17 | Gaetano Salvo | Manual calculator for analog and digital numbers |
US4994656A (en) * | 1988-11-14 | 1991-02-19 | Ng Wang C | Logic design slide rule |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US1892634A (en) | Calculating device | |
US922465A (en) | Calculating device. | |
US2068226A (en) | Changeable exhibitor | |
US4120451A (en) | Currency converter for use with pre-established and known conversion data | |
US2610792A (en) | Score indicator for boxing and the like | |
US1351692A (en) | Means for compiling tabular and statistical data | |
US4028529A (en) | Currency exchange calculator | |
US2146005A (en) | Indicating device | |
US2265372A (en) | Slide rule | |
US20090047642A1 (en) | Reversible arithmetic teaching device | |
US2098394A (en) | Recipe file | |
US3784093A (en) | Factormatic slide rule | |
US2553338A (en) | Income tax computing chart | |
US856573A (en) | Computing device. | |
US1227653A (en) | Accounting record-sheet. | |
US2268434A (en) | Tabulating card | |
US2221924A (en) | Device for indicating the resultant | |
US1959636A (en) | Game scoring device | |
US1613975A (en) | Assiqnobs of | |
US2006945A (en) | File indicator | |
US1203392A (en) | Interest-computing and multiplying machine. | |
US2135649A (en) | Scoring apparatus | |
US1526166A (en) | George e | |
US2092268A (en) | Calculator | |
US1729714A (en) | Calculator |