Pinion 1 rotates about a fixed axis and meshes with gear racks 2 and 3. When pinion 1 rotates counterclockwise, racks 2 and 3 move upward and to the right. This changes the angle of inclination of sliding link 4, which turns about fixed axis B, and the position of point A on sliding link 3'. Cross-shaped slider 5 moves along sliding link 3' at point A. Sliding link 6 passes through slider 5 perpendicular to link 3' and can move in fixed guide c only in the vertical direction. Link 6 is connected by turning pair D to slider 7 through which sliding link 8 passes. Link 8 turns about fixed axis 0. When pinion 1 rotates, point K of intersection of sliding links 3' and 8 describes portion q of a cubic parabola with the equation y=x³/(ab) where a=O͞B and b is the distance from the axis of rack 2 to the origin of coordinates.
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