The lengths of the links comply with the condition: A͞B=B͞C. Link 1, turning about fixed axis A, is connected by a sliding pair to slider 5. Slider 5 is connected by turning pair C to slider 4 which moves along guides a of link 3. Link 3 slides in fixed guides d-d. When link 1 turns through angle α, crank 2 turns through angle 2α, and slotted link 3 is displaced the amount x which is proportional to the cosine of twice the angle α, so that x=B͞C*cos(2α).
$1288$LG,MO$