Adding Machine Section, Burroughs Model 581

This is one of a series of adding machines and adding machine models prepared by the Patent Department of the Burroughs Adding Machine Company. It is a model of a key lock for adding machines invented by Frederick Dame. It includes a steel mechanism with one white plastic key, two key stems without keys, and two black-plastic rimmed numeral wheels. A complete set of nine white plastic keys with key stems is attached to the model. All the keys are octagonal. Keys for odd digits are concave, and flat for even digits. Complementary digits are indicated on the keys.
A metal tag attached to the object reads: B.A.M.CO. MODEL (/) NO. 581.
Objects 1982.0794.04 through 1982.0794.10 were received together as Burroughs Patent model 42.
Frederick Dame, “Key Mechanism for Calculating Machines,” U.S. Patent 1,791,265, filed August 12, 1929, granted February 3, 1931.
Currently not on view
Object Name
adding machine model
date made
Burroughs Adding Machine Company
Physical Description
plastic (overall material)
steel (overall material)
overall: 11 cm x 7 cm x 27 cm; 4 11/32 in x 2 3/4 in x 10 5/8 in
place made
United States: Michigan, Detroit
ID Number
accession number
catalog number
Science & Mathematics
Adding Machines
See more items in
Medicine and Science: Mathematics
Adding Machines
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Burroughs Corporation

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