Abstract: An apparatus comprises a main arm having links extending from a ground end to an effector end and allowing movement of the effector end from a first position to a second position, the links including at least a base link adapted to be pivotally connected to a base, and a spacing link pivotally mounted to a free end of the base link and extending to the effector end. A first 4-bar parallelogram has pivot joints at its corners and including the base link of the main arm. A second 4-bar parallelogram has pivot joints at its corners and including the spacing link of the main arm and an effector link at the effector end adapted to support an object. A serial interconnection is between the first 4-bar parallelogram and the second 4-bar parallelogram constraining the effector link to maintaining a constant orientation in at least two rotational degrees of freedom relative to the base.