Abstract
Nut former is a machine used for production of nuts. The core part of nut former is its cutting-and-feeding mechanism, which comprises a translating cam driven by slider-crank mechanism. For the conventional type of nut formers, an external force imposed by return springs is necessarily needed to maintain contact between cam and follower. The application of such a spring-loaded cam-follower system not only results in higher contact stress but also makes the machine undesirably incompact. To the end of solving these problems, this research introduces a novel configuration of translating cam mechanism with an intermediate link mounted between the cam and the translating follower. The intermediate link is made triple-arc-faced and pivoted on end-effector. The cam has two sets of cam contour which can be either grooved or ribbed form and the intermediate link is positively-driven because it remains multiple-point contact with cam contour at any instant. An analytical approach is addressed to illustrate how to synthesize such cam mechanism. With proper design of such cam mechanism, it can be found that application of the triple-arc-faced follower yields a reduction of the contact stress by 58.9% ~ 78.1% in comparison with using conventional roller follower and by 39.1% ~ 67.6% in comparison with the conjugate cam type, respectively.