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 vertically along uprights b. When link 1 turns through angle α, crank 2 turns through angle 2α, and slotted link 3 is displaced vertically by the amount y which is proportional to the sine of twice the angle α so that y=B͞C*sin(2α).
$1289$LG,MO$