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]

  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.