Abstract: A mechanism comprises a first Halbach cylinder having an inner cavity, the first Halbach cylinder magnetized to produce a first magnetic flux concentrated circumferentially inside the inner cavity. A second Halbach cylinder is concentrically received in the inner cavity of the first Halbach cylinder to concurrently form a rotational joint having a rotational axis. One of the Halbach cylinders is a rotor and the other of the Halbach cylinders is a stator, the second Halbach cylinder magnetized to produce a second magnetic flux concentrated circumferentially outwardly. An output is connected to the rotor to rotate therewith relative to the stator, the output applying a gravity load on the rotor, the gravity load being offset from the rotational axis, whereby the magnetic flux of the first Halbach cylinder and the second Halbach cylinder cooperatively produce a torque against the gravity load caused by the output.