Gear 1 is rigidly attached to plate cam 3, rotates about fixed axis A and meshes with gear 2 which is rigidly attached to plate cam 4 and rotates about fixed axis B. Link 5 is connected by turning pair C to follower 6 which turns about fixed axis D. Link 5 carries rollers a and b which roll along the contours of cams 3 and 4. The number of teeth of gear 2 is z₂=z₁-1, where z₁ is the number of teeth on gear 1. Therefore, to each revolution of gear 1, gear 2 makes n₂=(z₁/(z₁-1)) revolutions i.e. a full cycle of motion of the mechanism corresponds to n₁=z₁-1 revolutions of gear 1. Compression spring 7 holds rollers a and b in contact with cams 3 and 4.