The lengths of the links comply with the conditions: B͞C=C͞E=E͞F=F͞B=a, D͞C=D͞F=b and A͞B =A͞D. The mechanism always satisfies the condition D͞B×D͞E=a²-b²=k², where k is the inversion constant. When crank 1 turns about fixed axis A, point E travels along straight line q-q which is perpendicular to AD and is at the distance h from point D: h=k²/(2A͞B).
$703$LW,GI$