Wheels 1 and 2, whose outlines are two identical ellipses, rotate about fixed axes A and B which coincide with foci of these ellipses. Their outlines are centrodes in the relative motion of the wheels. Without taking the sign into account, the transmission ratio in each position of the mechanism is • i₁₂=ω₁/ω₂=B͞P/A͞P where ω₁ and ω₂ are the angular velocities of wheels 1 and 2, and P is the point of contact of the outlines and always lies on line AB. The average transmission ratio in a full cycle of motion of the mechanism is i₁₂=1. If the distances from the centres of rotation of the ellipses to their other foci, A͞F=B͞F₁ are denoted by c and their major axes C͞₁D₁=A͞B by l, then the transmission ratio varies once each cycle within the limits from i_min=(1-k)/(1+k) to i_max=(1+k)/(1-k) where k=c/l. Teeth are to be provided on the outlines of wheels 1 and 2 to obtain the full cycle of positive motion.
$2289$SG,3L$