Pinwheel calculator

These wheels, also called pinwheels, could be set by using a side lever which could expose anywhere from 0 to 9 teeth, and therefore when coupled to a counter they could, at each rotation, add a number from 0 to 9 to the result.

As part of a redesign of the arithmometer,[1] they reduced by an order of magnitude the cost and the size of mechanical calculators on which one could easily do the four basic operations (add, subtract, multiply and divide).

In "Machina arithmetica in qua non additio tantum et subtractio sed et multiplicatio nullo, diviso vero paene nullo animi labore peragantur", written in 1685, Leibniz described an arithmetic machine he had invented that was made by linking two separate machines, one to perform additions/subtractions and one for multiplications/divisions.

Antonius Braun was a native of Swabia; his machine, which he presented to the emperor in 1727, was cylindrical in shape and was made of steel, silver and brass; it was finely decorated and looked like a renaissance table clock.

His dedication to the emperor engraved on the top of the machine also reads "..to make easy to ignorant people, addition, subtraction, multiplication and even division".

Izrael Staffel, a polish clockmaker introduced his pinwheel machine in 1845 at an industrial exposition in Warsaw, Poland and won a gold medal in 1851 at The Great Exhibition in London.

"The operation of machines of this type was accomplished by means of pulling levers or knobs to set up the desired number.