- Pinwheel calculator
Pinwheel calculators were invented independently by
Frank S. Baldwin in theUSA (1872) andWilgott Theophil Odhner inRussia (1874). They reduced both the cost and the size of a mechanicalcalculator on which one could easily do the four basic operations (add, subtract, multiply and divide) by an order of magnitude.History
In Russia, Odhner's arithmometers were mass-manufactured first in 1886 by "W.T. Odhner, Maschinenfabrik & Metallgiesserei" and later in 1891 by the Odhner-Gill factory (фабрика Однера-Гиля) in
St. Petersburg . Pinwheel calculators were more popular inEurope (particularly in Germany) than in theUnited States .In 1924,
Felix Dzerzhinsky , the head of the RussianCheka , initiated the manufacturing of arithmometers. Later they were named "arithmometer Feliks" and served in theSoviet Union well into the 1970s, popularly known under the name "Iron Feliks ".Operation
"The operation of machines of this type was accomplished by means of pulling
levers orknobs to set up the desired number. Addition, subtraction,multiplication , and division were accomplished by means of revolvingdrum s. For addition they revolved in one direction, and for subtraction the direction was reversed. For multiplication the revolutions were repeated in the same direction as for addition, and for division they were repeated in the same direction as for subtraction. Two sets of dials provided a means of reading totals. In one the accumulation of totals appeared; in the other, there appeared the figure which was added, subtracted, multiplied, or divided." (The Office Appliance Manual, p. 88)ee also
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Difference engine External links
* [http://www.vintagecalculators.com/html/operating_a_pinwheel_calculato.html Instructions for a typical pinwheel calculator]
* [http://www.calculi.nl/page99.html Pinwheel calculator simulator (Windows executable)]
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