The lengths of the links comply with the condition: E͞C=C͞D. Link 1 oscillates within angle B'AB" about fixed axis A. Oscillation of link 1 is converted by links 2, 3 and 4 into reciprocation of slider 5. During one complete oscillation of link 1, slider 5 accomplishes two complete cycles of motion. The displacement s of point D of the slider from its extreme lower position, shown in the drawing, to its extreme upper position equals s=2(C͞D-a).
$1507$SC,6L$