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US3880349A - Cylindrical calculator - Google Patents

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US3880349A
US3880349A US400844A US40084473A US3880349A US 3880349 A US3880349 A US 3880349A US 400844 A US400844 A US 400844A US 40084473 A US40084473 A US 40084473A US 3880349 A US3880349 A US 3880349A
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sleeve
core member
data
variables
window
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US400844A
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James Richard Harte
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    • GPHYSICS
    • G06COMPUTING OR CALCULATING; COUNTING
    • G06GANALOGUE COMPUTERS
    • G06G1/00Hand manipulated computing devices
    • G06G1/02Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales
    • G06G1/04Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by construction
    • G06G1/08Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by construction with circular or helical scales
    • G06G1/085Devices in which computing is effected by adding, subtracting, or comparing lengths of parallel or concentric graduated scales characterised by construction with circular or helical scales borne by a cylinder

Definitions

  • the sleeve has a longitudinal slot in it acting as a 35/30-31 window to reveal a selected row of the data on the core.
  • references Cited longitudinally on the sleeve has a circumferential slot UNITED STATES PATENTS adapted to cooperate with the longitudinal slot in the 731 175 M190 ⁇ Goodman 235/87 R sleeve to reveal a particular part of the selected row of 19591632, 5/1934 Obidinc...33:iiiiiiiiiiiizii 235/87 R data- There is a mathematical relationship between 2.239344 4/1941 Sifrit 235/87 R the data revealed in the Core and on the Sleeve Whieh 2.595.153 4 1952 Malmgren 235/87 R my f r examp in th form f multiplication FOREIGN PATENTS OR APPLICATIONS tab! [68,188 6/1934 Switzerland 1. 235 87 R 2 Claims, 9 Drawing Figures F'SJENTEMPRZSIHYS SHEET 2 UP 2 FIGS.
  • CYLINDRICAL CALCULATOR This invention relates to a cylindrical calculator or multiplier of the kind employing a central cylindrical data-carrying core and a data carrying sleeve or tube mounted on the core.
  • An object of my invention is to provide an improved calculator of this type which facilitates the use of complex numerical and other data and enables the user to locate complex data. usually on a chart with a vertical and horizontal axes. with ease and rapidity.
  • a calculator comprises a cylindrical data-carrying core member. a data-carrying cylindrical sleeve rotatably mounted on the core member the sleeve having a longitudinal window adapted to reveal a selected column of data. and an outer tube slidably and rotatably mounted on said sleeve, said tube having a circumferential window adapted in conjunction with said longitudinal window to reveal selected data only of said selected column of data.
  • said cylindrical sleeve is an incomplete cylinder. the adjacent longitudinal edges of said sleeve forming between them a gap which acts as said longitudinal window.
  • FIGS. 1 to 4 and 7 are exploded views of components of a calculator. specifically for calculating multiplication tables up to 12 X l2. embodying the invention
  • FIG. 5 is a view of the same calculator fully assembled:
  • FIG. 6 is a view of an alternative form of calculator embodying the invention and in combination with a ball point pen;
  • FIG. 8 is a similar calculator adapted for the calculation of Great Circle Air Mile distances between various points.
  • FIG. 9 is a similar calculator adapted for the calculation of currency exchange rates.
  • the calculator shown in FIG. 5 is adapted to calculate multiplication tables up to II X II.
  • the component parts of the calculator are shown in detail in FIGS. 1 to 4 and 7.
  • the calculator comprises an inner cylindrical data carrying core 10 capped at each end by a flanged retaining cap 11 which has a serrated edge 11a to enable it to be gripped to hold the inner cylinder or core 10 firmly.
  • the core 10 carries data in the form of a grid of numbers 13 representing the products of multiplication tables.
  • the grid of numbers 13 is printed in the middle third of the core 10.
  • the upper and lower thirds 12 of the core 10 also have numbers 14 on them representing the multipliers associated with the products at 13.
  • the other two parts of the calculator are a data carry ing inner cylindrical sleeve which consists of two parts (although it may be made of a single sleeve not illustrated). and an outer tube.
  • the cylindrical multiplier or calculator shown in FIGS. 1 to 5 and 7 is intended to be used to teach children the multiplication tables.
  • the cylindrical multiplier (FIGS. 5 and 6) is designed so that it can reveal the product of two numbers by the manipulation of an inner sleeve and an outer tube (FIGS. 2 and 3, and FIG. 4) that concentrically surround an inner core or cylinder (FIG. 1, items 12, 13).
  • the inner core or cylinder (FIG. 1) has a grid of numbers 13 printed or embossed on its outer surface. This grid of numbers 13 represents the products of the multiplier (FIG. 1. item 14) and the multiplicand (FIG. 2, item 17).
  • retaining means At each end of the cyl inder are retaining means (FIGS. 1, 5, 6 and 7, item 11) that keeps the inner cylindrical sleeve (FIG. 2 item 15 and FIG. 3, item 18) in proper position. and also restricts the up and down movement of the outer tube (FIGS. 4. 5 and 6).
  • the inner sleeve shown in FIGS. 2 and 3 is composed of two parts, the outer part 18 (in FIG. 3) is of transparent material; and the inner part 15 (in FIG. 2) is composed of opaque material such as plastic or paper on which are printed numbers 17 that serve as multiplicands.
  • the inner opaque part 15 is then attached to the outer transparent part 18 by means of glue or other bonding material.
  • the inner opaque part 15 alone could serve the function of the two parts but the outer transparent part 18 serves to protect the numbers 17, and the edges of a slot 16 that serves as a transparent vertical window which. when rotated around the core 11 (FIG. 1); progressively reveals different columns of numbers 13 and 14. The width of this slot or transparent window 16 isjust wide enough to allow one column of numbers (FIGS.
  • FIG. 4 parts 19 and 20 is constructed so that a transparent horizontal window 20 is of sufficient height to reveal just one of the many rows of numbers 13 that are printed or embossed on the inner sleeve 15.
  • the transparent horizontal window 20 is located midway between each end of the'outer tube FIG.
  • inner sleeve 15 (FIGS. 2 and 3) and outer tube parts 19 and 20 (FIG. 4) normally allow only one number at a time from the grid of numbers 13 to be revealed through the point of intersection of the inner vertical transparent window 16 and the outer horizontal circumferential transparent window 20. (See FIGS. 5 and 6).
  • the numbers printed or embossed on the grid 13 of the cylinder represent products of multipliers 14 and multiplicands (FIG. 2, item 17).
  • the inner core 10 is so constructed that the numbers in columns 17 correspond exactly to the horizontal rows of numbers on grid 13 to which numbers 17 represent the multiplicand.
  • the grid of numbers 13 the products. and the numbers 14 above and below the grid represent the multiplier.
  • the inner core 10 (FIGS. 2 and 3) is of exactly the same height as the sleeve 15 (FIG. 2).
  • the inner sleeve 15 (FIGS. 2 and 3) can be freely rotated on the core 10 (FIG. 1) to reveal one column of numbers at a time through its transparent vertical window 16.
  • the column of numbers revealed through transparent vertical window 16 contain multipliers 14 above and belowithe column of products of that multiplier.
  • the column of products are organized on grid of numbers 13 in an orderly manner.
  • the outer tube parts 19 and 20 (FIG. 4) is only about two-thirds the height of the inner sleeve 15 (FIGS. 2 and 3) and the core 10 (FIG. 1).
  • the outer tube parts 19 and 20 can be moved up and down on the inner sleeve 15. This up and down movement allows horizontal window 20 of the outer tube to reveal any of the multiplicands (l7) printed-on the inner sleeve 15. This up and down movement also allows the products of this multiplicand l7 and the multiplier 14 in the column revealed by transparent band 16 to be viewed through the windows I6 and 20 at the point where transparent vertical window 16 intersects the transparent horizontal window 20. This is illustrated in FIGS. 5 and 6.
  • FIG. 8 illustrates how the same mechanism can be used to locate distances between two places.
  • a series of cities or locations are indicated on the horizontal axis, and the same-or different cities or locations are located on the vertical axis.
  • the distance is located at their points of intersection in a manner similar to the operation of the multiplier.
  • FIG. 9 illustrates how the same general mechanism can be used for currency exchange rates.
  • the inner cylindrical core could be constructed as a transparent tube, the end flanges could be made removable, and sheets of appropriate data inserted. The data sheets would be printed to conform with the grid. and pre-existing design.
  • FIG. 6 shows one application of the cylindrical multiplier.
  • FIG. 6 shows the incorporation of the cylindrical multiplier with a ball point pen 2].
  • FIG. 6 also shows a pocket clip 22 that can be depressed or released by moving ring 24 down or up on shaft 23. The reason for releasing the spring tension of the pocket clip is to allow for free movement of inner and outer tubes on the cylinder.
  • a calculator comprising:
  • a cylindrical core member carrying a data table thereon arranged in longitudinally extending columns and circumferentially extending rows. said data representing solutions;
  • said core member projecting axially in both directions from said table to opposed end portions, each of said end portions having retaining means thereon and each end portion bearing data representing first variables spaced from but aligned with said columns;
  • an opaque cylindrical sleeve rotatably mounted on said core member and having a longitudinal window for alignment with a selected first variable and the corresponding column, said sleeve bearing data thereon representing second variables spaced along said window commensurate with the spacing of said rows;
  • an opaque outer tube slidably and rotatably mounted on said sleeve having a circumferentially extending window for revealing a selected second variable and operable in conjunction with said window of the sleeve to reveal a solution on said core memher, said tube being of lesser length than said core member to reveal said first variable thereon selected by said sleeve while being of such length to completely cover said table regardless of said tubes location between the retaining means.
  • variables on the core member are numbers representing multipliers.
  • said variables on the sleeve are numbers representing multiplicands, and said columns of solution data on said core member comprise a grid of numbers representing products.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Calculators And Similar Devices (AREA)

Abstract

This invention relates to a cylindrical calculator or multiplier of the kind employing a cylindrical data-carrying core and a data-carrying sleeve or tube rotatable on the core. The sleeve has a longitudinal slot in it acting as a window to reveal a selected row of the data on the core. An outer tube rotatable on and slidable longitudinally on the sleeve has a circumferential slot adapted to cooperate with the longitudinal slot in the sleeve to reveal a particular part of the selected row of data. There is a mathematical relationship between the data revealed in the core and on the sleeve which may be, for example, in the form of multiplication tables.

Description

United States Patent 191 Harte Apr. 29, 1975 CYLINDRICAL CALCULATOR Primarv Examiner-Lawrence R. Franklin 76 I ent r: ame Rich rd Ha t 10 W. 1 O i Kansas g g: MO. 64112 Attorney, Agent, or Firm-D. A. N. Chase [22] Filed: Sept. 26, 1973 [57] ABSTRACT PP NOJ 400,844 This invention relates to a cylindrical calculator or multiplier of the kind employing a cylindrical data- 52 us. c1. 235/87 R; 35/31 E Carrying Core and e data-Trying sleeve of tube home 51 1m. (:1 G060 3/00 able the Core 9 [58] Field of Search 235/64, 79.5, 87 R; The sleeve has a longitudinal slot in it acting as a 35/30-31 window to reveal a selected row of the data on the core. An outer tube rotatable on and slidable [56] References Cited longitudinally on the sleeve has a circumferential slot UNITED STATES PATENTS adapted to cooperate with the longitudinal slot in the 731 175 M190} Goodman 235/87 R sleeve to reveal a particular part of the selected row of 19591632, 5/1934 Obidinc...33:iiiiiiiiiiiizii 235/87 R data- There is a mathematical relationship between 2.239344 4/1941 Sifrit 235/87 R the data revealed in the Core and on the Sleeve Whieh 2.595.153 4 1952 Malmgren 235/87 R my f r examp in th form f multiplication FOREIGN PATENTS OR APPLICATIONS tab! [68,188 6/1934 Switzerland 1. 235 87 R 2 Claims, 9 Drawing Figures F'SJENTEMPRZSIHYS SHEET 2 UP 2 FIGS.
CYLINDRICAL CALCULATOR This invention relates to a cylindrical calculator or multiplier of the kind employing a central cylindrical data-carrying core and a data carrying sleeve or tube mounted on the core.
An object of my invention is to provide an improved calculator of this type which facilitates the use of complex numerical and other data and enables the user to locate complex data. usually on a chart with a vertical and horizontal axes. with ease and rapidity.
According to my invention a calculator comprises a cylindrical data-carrying core member. a data-carrying cylindrical sleeve rotatably mounted on the core member the sleeve having a longitudinal window adapted to reveal a selected column of data. and an outer tube slidably and rotatably mounted on said sleeve, said tube having a circumferential window adapted in conjunction with said longitudinal window to reveal selected data only of said selected column of data.
Preferably said cylindrical sleeve is an incomplete cylinder. the adjacent longitudinal edges of said sleeve forming between them a gap which acts as said longitudinal window.
In the accompanying drawings:
FIGS. 1 to 4 and 7 are exploded views of components of a calculator. specifically for calculating multiplication tables up to 12 X l2. embodying the invention;
FIG. 5 is a view of the same calculator fully assembled:
FIG. 6 is a view of an alternative form of calculator embodying the invention and in combination with a ball point pen;
FIG. 8 is a similar calculator adapted for the calculation of Great Circle Air Mile distances between various points". and
FIG. 9 is a similar calculator adapted for the calculation of currency exchange rates.
The calculator shown in FIG. 5 is adapted to calculate multiplication tables up to II X II. The component parts of the calculator are shown in detail in FIGS. 1 to 4 and 7.
The calculator comprises an inner cylindrical data carrying core 10 capped at each end by a flanged retaining cap 11 which has a serrated edge 11a to enable it to be gripped to hold the inner cylinder or core 10 firmly. The core 10 carries data in the form of a grid of numbers 13 representing the products of multiplication tables. The grid of numbers 13 is printed in the middle third of the core 10. The upper and lower thirds 12 of the core 10 also have numbers 14 on them representing the multipliers associated with the products at 13.
The other two parts of the calculator are a data carry ing inner cylindrical sleeve which consists of two parts (although it may be made of a single sleeve not illustrated). and an outer tube.
The cylindrical multiplier or calculator shown in FIGS. 1 to 5 and 7 is intended to be used to teach children the multiplication tables. The cylindrical multiplier (FIGS. 5 and 6) is designed so that it can reveal the product of two numbers by the manipulation of an inner sleeve and an outer tube (FIGS. 2 and 3, and FIG. 4) that concentrically surround an inner core or cylinder (FIG. 1, items 12, 13). The inner core or cylinder (FIG. 1) has a grid of numbers 13 printed or embossed on its outer surface. This grid of numbers 13 represents the products of the multiplier (FIG. 1. item 14) and the multiplicand (FIG. 2, item 17). At each end of the cyl inder are retaining means (FIGS. 1, 5, 6 and 7, item 11) that keeps the inner cylindrical sleeve (FIG. 2 item 15 and FIG. 3, item 18) in proper position. and also restricts the up and down movement of the outer tube (FIGS. 4. 5 and 6).
The inner sleeve shown in FIGS. 2 and 3 is composed of two parts, the outer part 18 (in FIG. 3) is of transparent material; and the inner part 15 (in FIG. 2) is composed of opaque material such as plastic or paper on which are printed numbers 17 that serve as multiplicands. The inner opaque part 15 is then attached to the outer transparent part 18 by means of glue or other bonding material. The inner opaque part 15 alone could serve the function of the two parts but the outer transparent part 18 serves to protect the numbers 17, and the edges of a slot 16 that serves as a transparent vertical window which. when rotated around the core 11 (FIG. 1); progressively reveals different columns of numbers 13 and 14. The width of this slot or transparent window 16 isjust wide enough to allow one column of numbers (FIGS. 1, 5, and 6; items 13 and 14) at a time to be revealed. When the inner sleeve is constructed of a single member. the opaque qualities (FIG. 2, item 15) and the numbers representing multiplicands 17 could be printed or painted on the outer surface of a transparent tube. leaving a vertical band 16 unpainted and transparent. This vertical band 16 extends the full length of the tube in either instance.
The outer tube. FIG. 4 parts 19 and 20 is constructed so that a transparent horizontal window 20 is of sufficient height to reveal just one of the many rows of numbers 13 that are printed or embossed on the inner sleeve 15. The transparent horizontal window 20 is located midway between each end of the'outer tube FIG.
4. parts 19 and 20. Most of the outer tube. parts 19 and 20 is opaque. (FIGS. 4, 5 and 6) and this opaqueness (l9) obscures all but one row of numbers on the grid of products 13 and all but one numeral in one of the columns of multiplicands 17. The transparent horizontal window 20 on the outer tube (parts 19 and 20) does not reveal a full horizontal row ofnumbers 13 from the cylinder. as the opaque part 15 of the inner sleeve 15 obscures all but one number in a horizontal row of numbers of grid 13.
The combination of inner sleeve 15 (FIGS. 2 and 3) and outer tube parts 19 and 20 (FIG. 4) normally allow only one number at a time from the grid of numbers 13 to be revealed through the point of intersection of the inner vertical transparent window 16 and the outer horizontal circumferential transparent window 20. (See FIGS. 5 and 6).
The numbers printed or embossed on the grid 13 of the cylinder (FIG. 1) represent products of multipliers 14 and multiplicands (FIG. 2, item 17). The inner core 10 is so constructed that the numbers in columns 17 correspond exactly to the horizontal rows of numbers on grid 13 to which numbers 17 represent the multiplicand. the grid of numbers 13 the products. and the numbers 14 above and below the grid represent the multiplier. To effect this. the inner core 10 (FIGS. 2 and 3) is of exactly the same height as the sleeve 15 (FIG. 2).
As noted previously. the inner sleeve 15 (FIGS. 2 and 3) can be freely rotated on the core 10 (FIG. 1) to reveal one column of numbers at a time through its transparent vertical window 16. The column of numbers revealed through transparent vertical window 16 contain multipliers 14 above and belowithe column of products of that multiplier. The column of products are organized on grid of numbers 13 in an orderly manner.
The outer tube parts 19 and 20 (FIG. 4) is only about two-thirds the height of the inner sleeve 15 (FIGS. 2 and 3) and the core 10 (FIG. 1). The outer tube parts 19 and 20 can be moved up and down on the inner sleeve 15. This up and down movement allows horizontal window 20 of the outer tube to reveal any of the multiplicands (l7) printed-on the inner sleeve 15. This up and down movement also allows the products of this multiplicand l7 and the multiplier 14 in the column revealed by transparent band 16 to be viewed through the windows I6 and 20 at the point where transparent vertical window 16 intersects the transparent horizontal window 20. This is illustrated in FIGS. 5 and 6.
FIG. 8 illustrates how the same mechanism can be used to locate distances between two places. A series of cities or locations are indicated on the horizontal axis, and the same-or different cities or locations are located on the vertical axis. The distance is located at their points of intersection in a manner similar to the operation of the multiplier.
FIG. 9 illustrates how the same general mechanism can be used for currency exchange rates. In the instance of currency exchange rates. or other data that vary from time to time, the inner cylindrical core could be constructed as a transparent tube, the end flanges could be made removable, and sheets of appropriate data inserted. The data sheets would be printed to conform with the grid. and pre-existing design.
FIG. 6 shows one application of the cylindrical multiplier. FIG. 6 shows the incorporation of the cylindrical multiplier with a ball point pen 2]. FIG. 6 also shows a pocket clip 22 that can be depressed or released by moving ring 24 down or up on shaft 23. The reason for releasing the spring tension of the pocket clip is to allow for free movement of inner and outer tubes on the cylinder.
I claim:
l. A calculator comprising:
a cylindrical core member carrying a data table thereon arranged in longitudinally extending columns and circumferentially extending rows. said data representing solutions;
said core member projecting axially in both directions from said table to opposed end portions, each of said end portions having retaining means thereon and each end portion bearing data representing first variables spaced from but aligned with said columns;
an opaque cylindrical sleeve rotatably mounted on said core member and having a longitudinal window for alignment with a selected first variable and the corresponding column, said sleeve bearing data thereon representing second variables spaced along said window commensurate with the spacing of said rows;
an opaque outer tube slidably and rotatably mounted on said sleeve having a circumferentially extending window for revealing a selected second variable and operable in conjunction with said window of the sleeve to reveal a solution on said core memher, said tube being of lesser length than said core member to reveal said first variable thereon selected by said sleeve while being of such length to completely cover said table regardless of said tubes location between the retaining means. whereby to permit the selection of two variables. one on the core member and one on the sleeve, for which the solution relating the two variables will be revealed by the intersecting windows of the sleeve and the tube.
2. The calculator as claimed in claim 1, wherein said variables on the core member are numbers representing multipliers. said variables on the sleeve are numbers representing multiplicands, and said columns of solution data on said core member comprise a grid of numbers representing products.

Claims (2)

1. A calculator comprising: a cylindrical core member carrying a data table thereon arranged in longitudinally extending columns and circumferentially extending rows, said data representing solutions; said core member projecting axially in both directions from said table to opposed end portions, each of said end portions having retaining means thereon and each end portion bearing data representing first variables spaced from but aligned with said columns; an opaque cylindrical sleeve rotatably mounted on said core member and having a longitudinal window for alignment with a selected first variable and the corresponding column, said sleeve bearing data thereon representing second variables spaced along said window commensurate with the spacing of said rows; an opaque outer tube slidably and rotatably mounted on said sleeve having a circumferentially extending window for revealing a selected second variable and operable in conjunction with said window of the sleeve to reveal a solution on said core member, said tube being of lesser length than said core member to reveal said first variable thereon selected by said sleeve while being of such length to completely cover said table regardless of said tube''s location between the retaining means, whereby to permit the selection of two variables, one on the core member and one on the sleeve, for which the solution relating the two variables will be revealed by the intersecting windows of the sleeve and the tube.
2. The calculator as claimed in claim 1, wherein said variables on the core member are numbers representing multipliers, said variables on the sleeve are numbers representing multiplicands, and said columns of solution data on said core member comprise a grid of numbers representing products.
US400844A 1973-09-26 1973-09-26 Cylindrical calculator Expired - Lifetime US3880349A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5148974A (en) * 1991-12-13 1992-09-22 Millard Clapper Security mail box with improved anti-tamper means
USD402574S (en) 1997-10-31 1998-12-15 O'malley Robert Martin Fishing pole casting counter
EP0996076A1 (en) * 1998-10-23 2000-04-26 TENAILLE D'ESTAIS, Matthias Device for conversion between two systems of units, namely currency units, fountain pen and rule provided with this device
FR2821462A1 (en) * 2001-02-27 2002-08-30 M H L Distrib DEVICE FOR CORRESPONDING DATA OF A FIRST CATEGORY OF DATA WITH DATA OF A SECOND CATEGORY OF DATA
US20120028229A1 (en) * 2010-07-30 2012-02-02 James Richard Harte Augmented simple abacus with an underlying grid of numbers or a blank sheet
US10388174B2 (en) 2014-02-04 2019-08-20 Oswaldo Angel Writing instrument teaching system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US731175A (en) * 1903-03-03 1903-06-16 Joseph T Goodman Educational device.
US1959636A (en) * 1931-06-02 1934-05-22 Wesley Benton Tourtellotte Game scoring device
US2239344A (en) * 1939-08-04 1941-04-22 Robert L Sifrit Calculator
US2595153A (en) * 1952-04-29 Forecasting calculator

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2595153A (en) * 1952-04-29 Forecasting calculator
US731175A (en) * 1903-03-03 1903-06-16 Joseph T Goodman Educational device.
US1959636A (en) * 1931-06-02 1934-05-22 Wesley Benton Tourtellotte Game scoring device
US2239344A (en) * 1939-08-04 1941-04-22 Robert L Sifrit Calculator

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5148974A (en) * 1991-12-13 1992-09-22 Millard Clapper Security mail box with improved anti-tamper means
USD402574S (en) 1997-10-31 1998-12-15 O'malley Robert Martin Fishing pole casting counter
EP0996076A1 (en) * 1998-10-23 2000-04-26 TENAILLE D'ESTAIS, Matthias Device for conversion between two systems of units, namely currency units, fountain pen and rule provided with this device
FR2785067A1 (en) * 1998-10-23 2000-04-28 D Estais Mathias Tenaille CONVERSION DEVICE BETWEEN TWO UNIT SYSTEMS, ESPECIALLY MONETARY UNITS, AND A STYLOGRAPHER PROVIDED WITH THIS DEVICE
FR2821462A1 (en) * 2001-02-27 2002-08-30 M H L Distrib DEVICE FOR CORRESPONDING DATA OF A FIRST CATEGORY OF DATA WITH DATA OF A SECOND CATEGORY OF DATA
WO2002069237A3 (en) * 2001-02-27 2002-11-28 M H L Distrib Device for matching data from a first data category with data from a second data category
US20120028229A1 (en) * 2010-07-30 2012-02-02 James Richard Harte Augmented simple abacus with an underlying grid of numbers or a blank sheet
US10388174B2 (en) 2014-02-04 2019-08-20 Oswaldo Angel Writing instrument teaching system

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