Dorr E. Felt (1862–1930) invented the Comptometer. He was a young machinist in Chicago when he had a vision of real-time processing while observing the strike of staple-setters in his factory. He built a prototype with meat skewers and a discarded wooden macaroni box and took it to Robert Tarrant. The rest is history.
His all-metal Comptometers were built to survive the soul-crushing labour of an eight-hour shift. They became a standard by which all mechanical calculators were measured and they survived his death by some three decades.