Plus Adder (Adding machine)

Contributed by BBC Somerset

Plus Adder (Adding machine)

Guy Peter (1872-1948) invented one of the first mechanical calculators that became part of a modern range of office equipment. He spent a long time experimenting with the machine, taking out many patents from 1923-34 while at Vickers-Petters factory in Ipswich. He then returned to the Yeovil factory in 1927 to spend all of his time on the machine. Had the family known how long the experiments would take, they may not have continued with the project, but did support it into limited production. It was then named 'petometer'. Guy resigned his directorship in 1936 and sold the patents to the bell punch company in Uxbridge. He then moved to Uxbridge and took the apprentice who had worked with him on the project. The Bell Punch Company produced the Sumlock range of specialist office and calculating machines. The Petometer was the produced 'rapid plus', 'plus-adder' and many variants for office use into the 1950s and 1960s.

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