Title |
Primary Class |
Description |
Inventor |
Assignee |
Issue Date |
Patent No. |
Calculating-machine |
235/84 |
Circular slide rule. Based upon the fact that multiplication and division of numbers may be performed by the addition and subtraction of their logarithms. |
J.W.Nystrom |
___ |
March 4, 1851 |
US7961 |
Improvement in Calculators |
235/78R |
Circular slide rule. Performs addition, subtraction, multiplication and division based upon elementary arithmetic techniques. |
William Hart |
___ |
January 15, 1878 |
US199289 |
Improvement in Calculators |
235/67 |
Spiral helical scale slide rule. Enables arithmetical calculations of multiplication, division, involution and evolution required singly or in combination. A much longer scale, and hence potentially higher accuracy, than a straight or circular rule. |
George Fuller |
___ |
September 2, 1879 |
US219246 |
Slide Rule |
235/79.5 |
Cylindrical slide rule. A much longer scale, and hence potentially higher accuracy, than a straight or circular rule. |
Edwin Thacher |
___ |
November 1, 1881 |
US249117 |
Logarithmic sliding scale |
235/84 |
Circular engineers slide rule. Enables the extension of the circular scales in an endless manner from the end of one scale to the beginning of the other and so forth. |
Walter Hart |
___ |
July 31, 1888 |
US387070 |
Engineer’s slide rule |
235/70B |
Duplex slide rule (scales on both sides of the rule). Inverted scales on both sides of the rule. |
William Cox |
Keuffel and Esser Company, New York |
October 6, 1891 |
US460930 |
Cryptographic instrument |
380/56 |
Translating communication into and out of cipher in accordance with any selected collocation of letters, word or sentence of indefinite length adopted as a key. |
Richard Harte |
___ |
February 28, 1893 |
US492677 |
Logarithmic calculator |
235/79.5 |
Cylindrical slide rule. Improvement in redvision and root calculations. (French patent No. 217367) |
Julius Billeter |
___ |
January 23, 1894 |
US513172 |
Slide-Rule |
235/70A |
Two sliding scales introduced instead of one, whereby the application of the rule is extended to equations of five variables instead of three. |
Thomas H. Johnson |
___ |
May 22, 1894 |
US520114 |
Slide Rule |
235/70A |
Determining differences in elevation between two points when the stadia reading and vertical angle between them is known. |
Branch H. Colby |
___ |
July 30, 1895 |
US543612 |
An improved cylindrical slide rule |
-- |
A cylinder of wood, or celluloid, or other suitable material on which is marked, or printed, a graduated logarithmic scale in the form of a continuous spiral or other convenient arrangement, which scale may also be marked or printed on paper ,or other suitable material and then fastened to the cylinder in any well-known manner. |
Eagles James |
___ |
January 4, 1896 |
GB3937 |
Slide-Rule |
235/67 |
A pair of helical scales formed on cylindrical helicals where one is moveable longitudinally and revolubly along the other. Thus, the length of each scale exceeds greatly the length of the rule, and a much finer subdivision and delicate reading may consequently be achieved. |
James E. D. Yalden |
___ |
May 3, 1898 |
US603370 |
Slide Rule |
235/70R |
In order to enable certain calculation to be made using only one instrument, the slide rule is made in the form of a prism having three, four, five or more faces. |
Willie L. E. Keuffel |
___ |
May 10, 1898 |
US603695 |
Slide Rule |
235/70R |
Introduction of a series of springs maintaining the abutting scales in contact and a series of guides for the scales of the divided portion - to prevent wear. |
John G. D. Mack |
Eugene Dietzgen Company, Chicago, Illinois |
June 28, 1898 |
US606388 |
Slide-Rule |
235/70R |
Improvement upon Cox’s patent (460930) by inclosing two slides within the same rule. |
Willie L. E. Keuffel |
___ |
March 21, 1899 |
US621348 |
Title |
235/70R |
To secure the accuracy adjustment of the rule by making the rule on one or both sides of the slide separable or detachable from its base and providing it with means whereby after adjustment it may be rigidly secured in position. |
Willie L. E. Keuffel |
Keuffel and Esser Company, New York |
June 5, 1900 |
US651142 |
Calculating Instrument |
235/79.5 |
Small and efficient instrument. Composed of a few small cylindrical endless graduated scales of equal diameter mounted on each other. |
Roger W. Conant |
___ |
September 18, 1900 |
US657916 |
Slide Rule Runner |
235/70B |
Removing the transverse opaque slide frames from the runner and extending the transparent panel beyond the longitudinal edges of the rule and there connecting it with the longitudinal frame members to enable the clear view of the graduated scales beneath the runner. |
Willie L. E. Keuffel |
Keuffel and Esser Company, New York |
August 17, 1915 |
US1150771 |