The lengths of the links comply with the conditions: A͞C:A͞E=C͞Q:E͞P and A͞B:A͞D=B͞Q:D͞P. 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 E 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 D and B to link 1. For any configuration of the mechanism, points P, Q and A 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=C͞Q×E͞P-A͞C×A͞E=B͞Q×D͞P-A͞D×A͞B=const.
$734$LW,GI$