Multi-blade monolithic Euler springs with optimised stress distribution

Abstract

Euler springs are used for vertical suspension and vibration isolation as they provide a large static supporting force with a low spring-rate and use minimal spring material. To date, multiple single-width rectangular blades of uniform thickness and stacked flat-face to flat-face have been used in the post buckled state, with half of the blades buckling in each of opposing directions. For ultra-low-noise isolation the ends need to be clamped which results in stick-slip issues at the joints. In this study we investigate the benefits of forming side-by-side oppositely buckling blades from a single monolithic sheet of spring material. Additionally, we study how to distribute the stress evenly along the length of the blade by contouring its width, as well as finding the optimal contour to distribute the stress evenly around the tearing joints between oppositely bending blade sections. We show that this optimal shaping typically improves the inconveniently small spring working range by over 60 % compared to an equivalent rectangular blade.