The lengths of the links of four-bar linkage ABCD comply with the conditions: B͞C=D͞C=C͞M=3.12A͞B, A͞D=2.94A͞B and angle β=120°. When link 1 turns about fixed axis A, point M of link 2 describes path q-q which approximates a circle of radius R₁ or R₀ where ∆R=R₀-R₁ is a small value.
$679$LW,GI$