This compilation Copyright (C) 2005 Mike Sebastian. No copyright claim is made to original U.S. Government works.

Calculator Patents - Comptometer


U.S. Patent No. Assignee File Date Issue Date Inventor1 Product Title Comments
366945 Chauncey W. Foster and himself (Felt) July 6, 1886 July 19, 1887 Felt Comptometer Adding machine -
371496 Chauncey W. Foster and himself (Felt) March 12, 1887 October 11, 1887 Felt Comptometer Adding machine Improvement to 366,945
396034 Robert Tarrant and himself (Felt) May 31, 1887 January 8, 1889 Felt Comptometer Adding machine Improvement to 371,496
405024 Felt & Tarrant Manufacturing Co. January 19, 1888 June 11, 1889 Felt (no printing Comptometers) Adding machine Improvement to 371,496; printing
441232 Felt & Tarrant Manufacturing Co. March 8, 1889 November 25, 1890 Felt (no printing Comptometers) Type writing machine Printing with hammers instead of direct pressure
441233 (none) September 28, 1889 November 25, 1890 Felt (no printing Comptometers) Adding and recording machine Printing mechanism refinements
465255 (none) November 11, 1890 December 15, 1891 Felt (no printing Comptometers) Recording computing machine Printing mechanism improvements: print knob, leading zero suppression
568020 (none) September 10, 1894 September 22, 1896 Felt Comptometer Computing machine Improved zeroing mechanism
568021 (none) June 14, 1895 September 22, 1896 Felt (no printing Comptometers) Printing and calculating machine Change to mechanism - number keys are set, then a lever is pressed to perform the addition
590972 (none) April 28, 1897 October 5, 1897 Felt (no printing Comptometers) Duplicate printing mechanism for adding machines, type writers, &c. Duplicate printing without carbon paper, using single mechanism and single ribbon
628176 (none) May 31, 1898 July 4, 1899 Felt (no printing Comptometers) Tabulating machine Printing mechanism can print in tabular form
644287 (none) July 13, 1899 February 27, 1900 Felt (no printing Comptometers) Tabulating machine Improvement to 628,176 - improved paper handling
661121 (none) May 2, 1898 November 6, 1900 Felt Comptometer Calculating machine Improvement to 568,021 - simplification of mechanism
671109 (none) October 24, 1900 April 2, 1901 Felt Comptometer Calculating machine Adaptions for British Money calculations
693958 (none) August 17, 1899 February 25, 1902 Felt (no printing Comptometers) Duplicate printing mechanism for adding machines Improvement to 590,972 improved ribbon path for printing on two sheets of paper simultaneously
694955 (none) November 19, 1900 March 11, 1902 Felt (no printing Comptometers) Tabulating machine Printing - locks machine at end of sheet of paper
711487 Comptograph Co. April 29, 1901 October 21, 1902 Felt ? Tabulating machine Cross (row) tabulating
733379 (none) November 3, 1902 July 14, 1903 Felt Comptometer Casing for key operated machines Complete enclosure of mechanism to muffle noise - the classic Comptometer case style
749177 Comptograph Co. September 12, 1902 January 12, 1904 Felt Comptometer Calculating machine Mechanical improvements
762520 (none) June 29, 1903 June 14, 1904 Felt Comptometer Calculating machine Mechanical improvements to lighten the touch
762521 (none) June 29, 1903 June 14, 1904 Felt Comptometer Registering mechanism for calculating machine -
767107 (none) August 3, 1903 August 9, 1904 Felt Comptometer Canceling mechanism for calculators -
780271 Comptograph Co. May 21, 1900 January 17, 1905 Felt (no printing Comptometers) Combined tabulating machine and writing machine -
780272 Comptograph Co. March 30, 1901 January 17, 1905 Felt (no printing Comptometers) Tabulating machine Printing - locks machine when predetermined number of entries made
780273 Comptograph Co. September 17, 1903 January 17, 1905 Felt (no printing Comptometers) Tabulating machine Printing - different implementation to lock machine at end of column
853543 Comptograph Co. December 27, 1904 May 14, 1907 Felt Comptometer Tabulating machine Improvement to 749,177
889671 Comptograph Co. September 17, 1903 June 2, 1908 Felt Comptometer Total printing mechanism for listing machines Pushing main operating lever back prints total
960528 (none) September 16, 1908 June 7, 1910 Felt Comptometer Calculating machine Improved canceling mechanism, idiot proofing
982416 (none) April 4, 1910 January 24, 1911 Felt Comptometer Key for keyboard calculating machines -
982417 (none) August 22, 1910 January 24, 1911 Felt Comptometer Key for keyboard machines Improvement to 982,416
992950 (none) December 18, 1909 May 23, 1911 Felt Comptometer Calculating machine Lock keyboard if key not fully depressed
996009 (none) March 4, 1910 June 20, 1911 Felt Comptometer Calculating machine Mechanical improvements to lighten the touch
1003723 (none) January 6, 1911 September 19, 1911 Felt Comptometer Key action for calculating machines Change to pressure profile, heavyer initial pressure followed by lighter pressure
1028344 (none) November 28, 1911 June 4, 1912 Felt Comptometer Calculating machine Mechanical improvements
1066096 (none) July 12, 1912 July 1, 1913 Felt Comptometer Calculating machine Mechanical improvements
1072933 (none) April 6, 1913 September 9, 1913 Felt Comptometer Calculating machine Mechanical improvements
1072934 Felt & Tarrant Manufacturing Co. April 5, 1914 September 9, 1913 Felt Comptometer Calculating machine Improved canceling mechanism
1074689 Felt & Tarrant Manufacturing Co. September 30, 1912 October 7, 1913 Bollensen Comptometer Adding machine Adaptions for common fractions of high denominators
1074704 (none) April 5, 1913 October 7, 1913 Felt Comptometer Calculating machine Adaptions for fractions
1074705 (none) April 5, 1913 October 7, 1913 Felt Comptometer Calculating machine Improvement to canceling/zeroing mechanism
1088219 (none) September 1, 1911 February 24, 1914 Felt Comptometer Calculating machine Electric motor driven
1110734 Felt & Tarrant Manufacturing Co. March 3, 1914 September 15, 1914 Ziehm Comptometer Calculating machine Locking mechanism improvements
1357747 Felt & Tarrant Manufacturing Co. May 1, 1918 November 2, 1920 Turck Comptometer Calculating machine Improvement to canceling/zeroing mechanism
1357748 Felt & Tarrant Manufacturing Co. December 1, 1919 November 2, 1920 Turck Comptometer Calculating machine Improvement to 1,357,747 - canceling/zeroizing mechanism
1371953 Felt & Tarrant Manufacturing Co. July 18, 1918 March 15, 1921 Turck Comptometer Calculating machine Motorized
1391220 Felt & Tarrant Manufacturing Co. April 24, 1920 September 20, 1921 Turck Comptometer Calculating machine Second register
1449639 Felt & Tarrant Manufacturing Co. May 19, 1921 March 17, 1923 Turck Comptometer Calculating machine Locks canceling crank if erroneous partial key depression
1818425 Felt & Tarrant Manufacturing Co. September 9, 1927 August 11, 1931 Niemann Comptometer Calculating machine Keyboard locking mechanism to prevent erroneous entries from partial key depressions
1886883 (none) April 23, 1921 November 8, 1933 Johnson Comptometer Calculating machine Improved register control
2570068 Felt & Tarrant Manufacturing Co. June 15, 1945 October 2, 1951 Niemann Comptometer Keyboard interlock for calculating machines Improvement to keyboard locking mechanism when a key is partially depressed
2585578 Felt & Tarrant Manufacturing Co. May 9, 1945 February 12, 1952 Niemann Comptometer Decimal indicator Pivoting member can be moved to show or hide a painted spot through a hole in the case next to a number window to indicate a decimal point
2835440 Comptometer Corp September 1, 1953 May 20, 1958 Koch - Flash reading indicating means for registers Movable transparent colored filters move to distinguish groups of three digits in display window to improve reading accuracy

Notes:

1 Where multiple inventors, only first inventor's name is listed.


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Last updated November 5, 2006