Adding machineIn 1887, a patent for the adding machine was granted to Dorr Eugene Felt of Chicago, Illinois. His Comptometer was the first practical key-driven calculator with sufficient speed, reliablility and economic benefit. He called his original prototype the "Macaroni box", a rough model that Felt created over the year-end holidays in 1884-85. The casing was a grocery macaroni box, assembled with a jackknife using meat skewers as keys, staples as key guides and elastic bands for springs. Door improved his design, producing his earliest commercial wooden-box Comptometer from 1887 thru 1903, leading to the first steel case Model A (1904 that would be standard for the remainder for all "shoebox" models. Electric motor drive was introduced in the 1920's. |
