Slide Rule
Patents and Inventions
Invented by Edmund Gunter in 1630

The slide rule was invented by Edmund Gunter in 1630.

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

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