First- and Second-Order Centrodes of Both Coupler Links of Stephenson III Six-Bar Mechanisms

The subject of this paper is the formulation of a general algorithm that is aimed to obtain and analyze the first- and second-order centrodes of both coupler links of Stephenson III six-bar mechanisms, along with the corresponding pairs of Bresse’s circles. The position vectors of both pairs of instantaneous centers of rotation and acceleration centers are expressed as vector functions of the driving input angle of the mechanism and apply the fundamental theorems for velocities and accelerations, respectively. Thus, the proposed algorithm has been formulated by using vector algebra and validated through significant numerical and graphical results by devoting particular attention to the cases in which the second coupler link shows an instantaneous stop configuration, along with those where the first four-bar linkage reaches an asymptotic configuration. These results can be useful for designing and analyzing specific mechanisms for practical applications, such as composing the jaw-crusher machine, which has been selected as an example