The lengths of the links comply with the condition: O͞B=O͞C=O͞A=a. Gears 1 and 4 are of equal radius r. Gear 1 rotates about fixed axis 0 and meshes with gear 4 which rotates about fixed axis A. Lever OC, rigidly attached to gear 1, is connected by turning pair C to slider 6 which moves along cross-piece t-t of slider 7. Slider 7 moves along fixed guides p-p whose axis coincides with axis Oy. Link 2 turns about axis 0 and is connected by turning pairs B to links 3 and 8. Link 8 moves in cross-shaped slider 5 which has guides with axes perpendicular to each other. Link 3 is connected by a sliding pair to slider n which is rigidly attached to gear 4. When gear 1 rotates about axis 0, point D describes virtual parabola q-q with the equation [a²x-(a² — 2y²)sqrt(a² — b²)]²= 4b²y²(a²-y²) where b is a constant dimension of the mechanism.
$1772$GL,Ge$