Design of Spherical Crank-Rocker Mechanism With Optimum Transmission

Abstract

Spatial and spherical mechanisms must not be designed for optimum transmission characteristics as plane mechanisms. The transmissivities and transmission angles in spatial and spherical mechanisms are determined by the skew angles between the pair axes on the links. A spherical crank-rocker mechanism is optimized to satisfy a prescribed advance-to-return time ratio and to have an optimum torque-to-torque transmissivity. Design equations and some illustrative design tables are given. It is illustrated that a spherical mechanism optimized as a plane mechanism may be a structure. A graphical method of designing spherical crank-rocker mechanisms, using stereographic projections, is also presented.