Plus & Sumlock Mechanical Calculators
Sumlock Sumlomatic
Photographed at the computer museum at Bletchley Park, England. May not currently be on display.
Sumlomatic
A full keyboard Sterling Currency "Comptometer" type machine with a multiplier register.
According to an exhibition review in "Office Magazine" for June 1958: "The star on the Sumlock stand is the Sumlomatic. This is a new key-driven calculator with a multiplier register as well as the usual working register and store register. Digits for the multiplier (the lowest-register in the illustration) are set from the keyboard by means of a transfer button (seen on the right) which is also used to transfer digits from the working register to the store register. For repetitive multiplication by the same factor the multiplier register is provided (on its left) with a locking switch. The large key seen to tthe left of the board is the multiplier control. Whilst addition and subtraction can be in £ s. d., multiplying must be in decimals. Division is done by turning to a printed table of reciprocals and then multiplying. In busy commercial offices where several kinds of computation are done, the use of the Sumlomatic will undoubtedly lead to a daily saving of many thousands of key depressions as compared with previous models. This remarkable new model weighs 341b. and costs £330 [about US$900]."
