Synthesis of Spatial Four-Bar Mechanisms : Part II, Synthesis of Mechanisms with Two Spheric Pairs

Abstract

In Part II, are developed the methods of dimensional synthesis of two spatial four-bar mechanisms, A1·2·1 mechanism having two revolute and two spheric pairs and A1·2·2 mechanism having one revolute, one prismatic and two spheric pairs : eight-precision-point synthesis of A1·2·1 mechanism and four- and six-precision-point syntheses of A1·2·2 mechanism are introduced. The conditions that both mechanisms are symmetrical are considered and the syntheses to generate symmetrical functions are also introduced : the functions generated by A1·2·1 and A1·2·2 mechanisms may coincide with the ideal functions at ten and eight points respectively. Examples of the syntheses are presented, which show that both mechanisms may generate much more precise functions than planar four-or six-bar mechanisms do.