American Adding Machine, Model 0

This lever set non-printing manually operated adding machine has an etched steel case painted black. Seven levers move in circular arcs between slots in the case. The case is painted along the edges of the slots with the digits from 0 to 9 (large and in black and white) and 9 to 0 (small and in red). The large digits are used for addition, the small ones for subtraction. A corrugation or depression in the cover is found at the place of each digit. Digits are set by placing the index finger in the corresponding depression and raising the lever by the thumb until it is stopped by the finger. They are entered by moving down a metal handle with a wooden knob on the right side. The result appears in seven windows above the levers. Rotating a knob on the left side of the machine transforms the action of the handle from addition to zeroing. Another handle on the right side zeros digits set incorrectly. The machine has four rubber feet.

The machine is marked on a plaque attached to the front: AMERICAN (/) ADDING MACHINE (/) AMERICAN CAN COMPANY (/) ADDING MACHINE DIVISION (/) CHICAGO, ILL. No 1153. It is also marked there: PAT. AUG. 27, 1912 (/) OTHER PATS. PEND.

By mid-1922, American Adding Machines were made by the American Adding Machine Company of Chicago. Compare MA.333921.

References:

J. H. McCarthy, The American Digest of Business Machines, Chicago: American Exchange Service, 1924, pp. 27, 518.

Jervis R. Harbeck, "Adding-Machine," U.S. Patent 1,036,614, August 27, 1912.

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