Patent ID: 6838796

Claim:
A rotational control apparatus comprising: a first assembly rotatably mounted to a first shaft of a first support mount; a second assembly rotatably mounted to the first assembly, wherein the second assembly is axially moveable relative to the first assembly, the first and second assemblies having respective circumferential surfaces adjacent to and spaced from one another, the first and second assemblies further having respective radial surfaces that frictionally engage one another when the second assembly is in a first axial position, and the respective radial surfaces of the first and second assemblies disengage when the second assembly is in a second axial position, wherein the second assembly is capable of rotation independent of the first assembly when the second assembly is in the second axial position; and an eddy current drive comprised of a first eddy current coupling assembly and a second eddy current coupling assembly, the first eddy current coupling assembly associated with the circumferential surface of the first assembly and the second eddy current coupling assembly associated with the circumferential surface of the second assembly adjacent to and spaced from the first eddy current coupling assembly, wherein the second eddy current coupling assembly is adjacent the first eddy current coupling assembly with an air gap therebetween.