Elastic element showing low stiffness loss at large deflection

Compliant mechanisms like a parallel guidance and a cross pivot flexure contain leaf-springs. The basic elastic elements like leaf-springs and wire flexures constrain Degrees-Of-Freedom (DOFs) when flat or straight respectively. However, when deflected these elastic elements lose stiffness rapidly. Therefore, mechanisms containing leaf-springs and wire flexures are suitable for small deflections only. This paper presents an elastic element, a so-called ‘curved hinge flexure’, which shows only a limited stiffness decrease at large rotational deflections of the initially 3 stiff directions. When comparing a curved hinge flexure with a single leaf-spring with comparable rotational compliance over a ± 15 degrees stroke, the stiffness in the stiff directions is 2.5 to 14 times higher.