David Sundstrand Explained

David Sundstrand (1880-1930) was a Swedish-born American inventor of the 10-key adding machine, 10-key calculator keyboard, a 10-keypad now used on computer keyboards, and a co-founder of Sundstrand Corporation.

Sundstrand's 1914 adding machine had the first now common place keyboard for 10-key calculators and numeric keypads. This 1914 invention was filed as patent No. 1198487.^[1] This invention was seminal to the development of an extensive range of machines that continued for decades into the 1950s. ^{[2] [3] [4] [5] [6] [7] [8]}

Notes and References

1. https://patents.google.com/patent/US1198487 Patent number: 1198487;Filing date: Mar 14, 1914;Issue date: Sep 19, 1916
2. https://www.nytimes.com/1972/01/06/archives/oscar-sundstrand-inventor-dies-at-82.html?sq=inventor%2520dies&scp=107&st=cse New York Times:OSCAR SUNDSTRAND, INVENTOR, DIES AT 82;January 6, 1972
3. https://web.archive.org/web/20120901153523/http://www.diycalculator.com/sp-mechgold.shtml#A1 The Golden Age of Mechanical Calculators;The Evolution of the Modern Calculator Keypad
4. http://www.schoepski.com/states/illinois/sundstrand/sundstrand.htm History of Sundstrand machine tool corporation
5. http://www.hsassociation.org/Files/HS_Association/Global/US-en/test/50-Year_HSA_Book_%28Pgs_253-272%29_-_Sundstrand_History,_Misc.pdf Rockford Tool Company 1905
6. https://patents.google.com/patent/US1329028 Patent number: 1329028;Filing date: Mar 11, 1912;Issue date: Jan 27, 1920
7. http://retrocalculators.com/Sundstrand.aspx Retrocalculators;Sundstran adding machine
8. http://www.fundinguniverse.com/company-histories/Sundstrand-Corporation-Company-History.html Sundstrand Corporation Company History;In 1914 David Sundstrand, Oscar's brother and an employee at the Rockford Milling Machine Company, developed a ten-key adding machine.