The lengths of the links comply with the conditions: A͞B:A͞C=B͞P:C͞Q and A͞E:A͞D=E͞P:D͞Q. Links 1 and 2 turn about fixed axis A which is the centre of inversion transformation. Links 3 and 4 are connected by turning pairs B and C to link 2 and by turning pairs P and Q to links 5 and 6. Links 5 and 6 are connected by turning pairs E and D to link 1. For any configuration of the mechanism, points A, P and Q lie on a single straight line. When point P or Q travels along any arbitrary curve, the other point describes a curve which is the inversion of the first curve. Hence, the mechanism accomplishes inversion transformations of the form A͞P×A͞Q=B͞P×C͞Q-A͞C×A͞B=A͞E×A͞D-E͞P×D͞Q=const.
$738$LW,GI$