Accoson A

Coplanar Toothed Gear Adding Machine

ca. 1910

English toothed gear adding machine for the calculation of amounts with a maximum of 4 digits in British currency. Manufacturer is the company A. C. Cossor & Sons, London, which is still known for its measuring instruments. Around 1910, it built a disc adder under the company label Accoson (abbreviation from the name of the company founder Alfred Charles Cossor), which was developed by son Frank Cossor (instrument maker) and Thomas W. Flory (engineer). The three coplanar toothed gears are complemented by a pointer device on the toothed gear on the left (for pounds): a pointer is carried along by an internal spiral from the center of the gear as it rotates toward the rim, and indicates the tens of the pound amounts at intervals of 20. The carryovers are executed according to the currency division. Apparently, another larger version (model B) has been manufactured.