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Filed: Nov. 11, 1890
Issued: Dec 15, 1891
Inventor: Dorr E. Felt
In 1891, Dorr Felt invented a device designed to improve upon the existing "recording machines which compute." Felt described the improvements in his device as follows:
"The leading object of my invention is to provide an improved recording-machine which will record the answer or result indicated by the numeral-wheels by pressing a knob instead of striking the amount of the answer on the keys."
Image taken from U.S. Patent 465,255 - Digitized by Google