David Sundstrand

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]}

References

1. Patent number: 1198487;Filing date: Mar 14, 1914;Issue date: Sep 19, 1916
2. New York Times:OSCAR SUNDSTRAND, INVENTOR, DIES AT 82;January 6, 1972
3. The Golden Age of Mechanical Calculators;The Evolution of the Modern Calculator Keypad
4. History of Sundstrand machine tool corporation
5. Rockford Tool Company 1905
6. Patent number: 1329028;Filing date: Mar 11, 1912;Issue date: Jan 27, 1920
7. Retrocalculators;Sundstran adding machine
8. 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.