Stiffness and stress characteristics of the generalized cross-spring pivot

The generalized cross-spring pivot, formed by crossing two leaves symmetrically at an arbitrary position along the length, can be employed widely in precision machine due to plenty of good performances. The stiffness and stress characteristics are important consideration for this pivot, but some of these attributes have not been revealed. In this paper, a simple model for stiffness prediction is first established based on some accurate approximations. Then moment stiffness and force stiffness are analyzed in order to better characterize the influences of the geometric parameters. After investigating the effect of the vertical force, the constant stiffness property is captured, and an approach to the low rotational stiffness is presented according to the buckling load. Moreover, the stress analysis is also implemented on purpose that the properties of the influencing factors (such as geometric parameters and loads) can be characterized and the pivot with large motion range can be fulfilled by stress checking. Finally, the characteristics, revealed by the analysis model, are validated by finite element analysis (FEA).