Abstract: Two coaxial main shafts are the output and the input of a variable-speed-ratio transmission wherein a transfer gear on one of these shafts is in permanent mesh with a plurality of coacting gears on respective ancillary shafts paralleling the main shafts, each ancillary shaft also carrying one or more speed-changing gears in permanent mesh with one or more associated gears mounted idle on the other main shaft and adapted to be selectively clutched thereto. The transfer gear has an annular body with external teeth which surrounds its supporting shaft with clearance, a flexible ring being disposed in that clearance with freedom of limited radial deformation and in positive engagement with both the shaft and the gear body to interconnect them for joint rotation. Teeth or other coupling formations on the inner and outer ring surfaces, peripherally offset from one another and separated by freely deformable ring sections, engage complementary formations on the shaft and within the gear body, respectively.

Abstract: A nut on a helically threaded steering shaft, held against rotation, carries a first set of involute teeth meshing with a second set of involute teeth on an adjoining gear sector which pivots on an axis skew to that of the shaft. The two sets of teeth have centers of curvature offset from the sector axis but aligned with that axis in a midposition in which they engage each other without play; upon a shift of the nut to either side, the tooth clearance or backlash increases progressively while the transmission ratio either increases or decreases, depending upon the relative positions of the two centers of curvature and the sector axis. In a limiting case, the radius of curvature of one set of teeth is infinite.