Shaft 1 with concave toroidal friction wheel a rotates about fixed axis A-A. Shaft 3 with convex toroidal friction wheel b rotates about fixed axis B-B. Between wheels a and b, and in contact with them, is spherical ring 2. The generatrices d and e of wheels a and b, and f of the inner and outer surfaces of ring 2 are circular arcs described from the common centre 0 which lies on fixed axis C-C. Ring 2 is supported by rollers 4 of link 5 and can swivel with this link about axis C-C of frame 6 to set ring 2 in various positions with respect to wheels a and b. The pressure required between the friction surfaces is developed by screws 7 which push against slide-blocks 8. Blocks 8 can slide along slots m in frame 6, and carry the bearings of shaft 1. The transmission ratio from shaft 1 to shaft 3 is i₁₃=ω₁/ω₃=n₁/n₃=(l-R₂”*cos(φ))/(k-R₂’*cos(φ)) where ω₁, ω₃, n₁ and n₃ are the angular velocities and speeds (in rpm) of shafts 1 and 3, I and k are the distances from axis C-C to axes B-B and A-A, R₂’ and R₂” are the outer and inner radii of the middle section of ring 2, and φ is the angle of swivel of ring 2 about axis C-C.
$3465$CF,IV$