Discovering the Arithmometer A glance back at the

Discovering the Arithmometer A glance back at the history of mechanical calculators by Tim Kostka, for Bits On Our Mind, March 9, 2005. Purpose • Create and validate a 3 D model of the Arithmometer • Print the model through the use of rapid prototyping • Verify the integrity and accuracy of the printed model • Distribute the model to outside groups interested in the device Background • Built by Thomas de Colmar in 1820 • First mechanical calculator reliable enough for workplace use • Performed addition, subtraction, indirect multiplication and division • Could perform calculations on numbers of up to 9 or more digits • Received commercial success from 1820 until the early 1900’s The Arithmometer was commercially successful from 1820 until the 1900’s. Method • Examine technical drawings of the device • The capability for this came from 19 th century technical drawings of the device made by Franz Reuleaux • Create a 3 D model using Solid. Works • Validate the dynamics of the model in Cosmos. Motion • Print the model using rapid prototyping • Identify any problems with the model and improve the design Future Plans Only part of the Arithmometer was modeled. This shows a rendering of two place digit elements. The original had from five to nine of these. • Improve upon the current rapid prototyped model • Print an updated version that incorporates these improvements • Publish the results and make them available to outside sources How Does It Work? • The operator would move the sliders to represent an input number • The crank would be turned one complete revolution • The step gear would advance the displayed digit • When the digit turned from 9 to 0, the carry mechanism would be triggered and the adjacent digit would be increased by one • If triggered, the carry mechanism would be reset • The output numbers would then reflect the calculation result • The operator would continue to perform the next calculation The first rapid prototype model was printed in December 2004. An improved version is currently being developed and will be printed soon.