Abstract: Positive-drive cam mechanisms are used in a great variety of applications and are of complexity and speciality in synthesis theory and methods. Based on the concepts “floating axis”, “instantaneous and whole nested interval” and introducing the new concepts “go and return travel”, “radius-marking line”, It deeply and systematically researches the second mechanisms task of conjugate-cam, groove-cam and yoke radial cam with roller follower. Research results is as follow: not being simple combination and summation of force-drive cam mechanisms, the synthesis of positive-drive cam mechanisms is of complicated, deep, special and original research cultivation. Regarding the yoke radial cam with roller follower as sample, a series of research thought , research method and research conclusions are obtained. A mechanism synthesis example is displayed.

Key words: Go(return)travel, Instantaneous(whole) nested interval, Positive-drive, Radius-marking line, Yoke radial cam with roller follower