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.
[1] This invention was seminal to the development of an extensive range of machines that continued for decades into the 1950s.
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