Identical toroidal friction wheels 3 are mounted on the splines of shaft 1 and rotate about fixed axis A-A. Identical spherical friction wheels 4 are keyed to shaft 2 and rotate about fixed axis B-B. The generatrix a of wheels 3 is a circular arc of radius R described from point 0₂ lying on axis B-B in its extreme upper position. The generatrix b of wheels 4 is a circular arc of radius r described from point 0₁ lying on axis B-B. Radius R is somewhat larger than radius r. The transmission ratio is varied by vertical displacement of axis B-B. Springs 5 tend to push wheels 3 apart along the splines of shaft 1; thereby holding them in engagement with wheels 4.
$3476$CF,IV$