The lengths of the links comply with the conditions: A͞C=K͞B and B͞C=K͞A. Elliptical gears 1 and 2 are of the same shape and size, and are rigidly attached to links 3 and 4. Connecting rod 5 is connected by turning pairs E and G to link 4 and slider 6. Slider 6 moves in a fixed guide. Centres K and D of rotation of the gears coincide with foci of the ellipses. Elliptical gears 1 and 2 can be replaced by crossed-crank linkage DNMK in which the lengths of the links comply with the conditions: D͞N=K͞M and N͞M=D͞K, and where points N and M also coincide with foci of the ellipses. Links 3 and 7 rotate in the same direction at the same angular velocity.
$1749$GL,ML$