This model is likely model D12 from the Reuleaux-Voigt catalog. It is a double-slider mechanism. This mechanism is known to trace space curves of an exact ellipse. It is similar to the Reuleaux-Voigt model D10, that Reuleaux attributed to Leonardo-da Vinci. In the model D12 or UK25 the instructor or student can change the parameters of the ellipse. A piece of chalk is used to trace the curve on the flat plate. Engineer-scientists such as Redtenbacher were very interested in representiing mathematical curves or functions with kinematic linkages and mechanisms.

Francis Moon 2005-00-00