Abstract: Generally, any transmission mechanism system is built by some 3-D space four-bar linkages, and they are linked together one by one as a chain. In this paper, by geometrical analysis, a general formula can be found from which the driven turn-arm angle can be derived by the given driving turn-arm angle. By using translated coordinates method the rotation metrax A is obtained, and a proof is given as well. A mechanism system for its every four-bar linkage can be solved by using this formula. The required mechanism transmission ratio is finally got. The above is the principle techniques on which the analysis in this paper is based. The method described are suitable for the computer programming technique.

Key words: algorithm, four-bar linkage, transmission mechanism