Abstract: The subject invention provides a parallel or closed loop mechanism for moving and positioning a member in space. The mechanism includes three branches each provided with at least two link members being serially connected together by a spherical elbow joint whereby the first and second link members are rotatable with respect to each other about any axis passing through a center of the first joint. The mechanism is provided with actuators for moving each branch and the first links of each branch are rigidly connected at an end portion thereof to the actuator means. The mechanism includes three revolute joints each defining a longitudinal axis of rotation. Each revolute joint is connected to an associated second link member so that the longitudinal axes of all third joints intersect at a point and the revolute joints are interconnected so that the three branches form three parallel or closed loops.