The development of vehicles for the exploration in the lunar environment is a topic of great interest. In particular, recently, there has been a growing attention toward the lunar rovers for working missions since the building of lunar bases is a primary objective for the lunar exploration. However, these vehicles have peculiar requirements to be taken into account in the design of each component. In this paper a particular component of a worker rover, developed as a collaboration between two academic institutions, has been designed for an optimal functionality. Each leg of this rover comprises a mechanism for lifting weights and the component considered, a decoupling joint, is a part of this mechanism. The design optimization was performed by means of parametric modelling and numerical simulations