The 6” x 6” tin toy prototype of the model was patented by one William Robertson in 1916 and was made by the Educational Novelty Company of Dayton , Ohio, U.S.A . Graham Jost of Melbourne, Australia, spotted the prototype in a museum and decided it could be replicated in Meccano. Consul's “calculating procedure" is disarmingly simple: alignment of the toes of his feet beside any two numbers on the scale across the base cause the downward-pointing Pawls representing the thumbs to move in such a way as to indicate the "sum or multiplication of those numbers, from the appropriate tabular backing card"
The model has been a great success at several exhibitions with both adults and children, all are fascinated by the fact that a simple mechanical device can do multiplication or addition without any need of electronics.
The plans for the model were published in Constructor Quarterly number 70, December 2005, pp. 32-35.
May 09 2006 Revised May 19 2015