Addo Multo Mod 113 Pinwheel Calculator

In 1874, Willgodt Theophil Odhner from Karlstad, Sweden, designed his first arithmometer, or hand-cranked calculating machine. After Odhner's original patent had expired, various manufacturers started production of calculators following Odhner's successful design.

One of them was the Multo, manufactured by a subsidiary company of Addo, which later was to merge with the Facit-Odhner concern. Multos were built between about 1949 and 1966, although the Multo name was used on some models of the Odhner as late as 1969. The grey machines illustrated probably date from the 1950s.

The "pin-wheel" from which these calculators take their name is a circular disc or wheel which has nine retractable pins extending radially around part of its circumference. The pins can be extended or retracted by a setting mechanism, which is generally operated by rotary levers. The pin-wheels and setting rings are assembled into a "rotor" or cylinder, which rotates forward or backward as the handle is turned. The extended pins act as gear teeth to advance a register by the corresponding number of places.

The Multo pinwheel calculator was also sold under the Dixi brand name. There also was a "badge-engineered" Multo which otherwise is identical to the Bernadotte-cased Odhner.

Digits: 10 rotor, 8 counter, 13 accumulator
Dimensions: Body 170W x 160D x 130H, overall width 310mm
Weight: 5.9 kg
Manufactured: Malmo, Sweden, 1950s

Our Multo machine was very kindly donated by Aubrey Thyer.

Manufacturer: Addo
Date: 1950

This exhibit has a reference ID of CH12154. Please quote this reference ID in any communication with the Centre for Computing History.

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