A novel one-DoF gravity balancer based on cardan gear mechanism

Abstract

This paper presents a new spring-based gravity balancer for carrying one-DoF rotating payload. The proposed balancer is an integration of the inverted Cardan gear mechanism and a planetary gear train. Unlike other approaches that restrict to ideal zero-free-length spring, the design here achieves perfect static balancing by employing practical tensile spring. In addition, the proposed mechanism contains revolute pairs and spur gear pairs only, which expect a high transmission efficiency under reduced friction. The balancing condition is derived via energy conservation method and is verified by ADAMS simulation.