Harmonic drive using guided, floating cam driven cylinders as power

Abstract

A device for rotating a first structure relative to a second structure has a rotatable shaft for attachment to the first structure. A first cylinder is coaxially attached to the rotatable shaft, and has a plurality of bearing constraining apertures for holding a plurality of bearings. A hollow fixed member for attachment to the second structure has a coaxially attached second cylinder outside of the first cylinder. The second cylinder has a plurality of bearing seats on its inside wall for selectively receiving the bearings. The number of bearing constraining apertures is different from the number of bearing seats, so that the bearings are harmonically aligned by the constraining apertures to be movable to within the bearing seats only at selected progressive locations. A handle is coaxially and rotatably mounted to the fixed member, and carries a cam inside the first and second cylinders. The cam has a protruding cam face in one location to sequentially engage the bearings to urge the engaged bearings into bearing seats with which they align. The cam also has a recessed cam face in another location that allows the bearings to move laterally with movement of the first cylinder without engaging the bearing seats in nonaligned locations. Thus, when the handle is rotated with respect to the fixed member, the bearings engaged by the cam are progressively forced sequentially within the bearing constraining apertures into the tapered bearing seats of the second cylinder to move the first and second cylinders relative to each other.