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Crank 1, turning about fixed axis 0 , moves in sliders 3 and 4. Slider 3 is connected by turning pair K to slider 5 which moves along extension p of slider 2. Extension q of slider 2 moves in slider 6 which is connected by turning pair A to sliders 4 and 7. Slider 7 moves along fixed guides m whose axis is perpendicular to the axis of fixed guides l along which slider 2 moves. When sliding link 1 turns about axis 0 , point K describes a parabola with the equation y=x²/a*tan(α)+x/tan(α) where a = distance from axis Oy to vertical guides m α = angle between extensions p and q.