Multo 13-5150 Pinwheel Calculator (about 1950)

The Addo company of Malmo in Sweden produced a range of slide-set adding machines from 1920. These were replaced in 1927 by full-keyboard adding and listing machines. Ten-key machines were produced from 1936, and pin-wheel machines under the "Multo" brand from 1949. Addo/Multo was absorbed into the Advidaberg/Facit/Odhner group in 1966. The Addo name continued to appear on Odhner pinwheel machines until production ended around 1970.

The Multo range was designed specifically for single-handed operation, with all of the controls located on the right-hand side.

A button on the front of the machine releases the carriage and returns it fully to the left. There is no tens-carry on the counter, and no back-transfer mechanism.

This calculator is one of many that were manufactured as a copy of Odhner's arithmometer which was a very successful mechanical calculator invented in Russia in 1873 by W. T. Odhner, a Swedish immigrant. Its industrial production officially started in 1890 in Odhner's Saint Petersburg workshop. Even though the machine was very popular, the production only lasted thirty years until the factory was nationalised and closed down during the Russian revolution of 1917.From 1892 to the middle of the 20th century, independent companies were set up all over the world to manufacture Odhner's clones and, by the 1960s, with millions sold, it became one of the most successful type of mechanical calculator ever designed.

Our Multo Pinwheel calculator has a model number of 13-5150 and was very kindly donated by Harvey Jones.

Manufacturer: Addo
Date: 1950

This exhibit has a reference ID of CH7138. Please quote this reference ID in any communication with the Centre for Computing History.

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