The lengths of the links comply with the conditions: A͞B:A͞D=B͞Q:D͞P and A͞C:A͞E=C͞Q:E͞P. Links 1 and 2 turn about fixed axis A which is the centre of inversion transformation. Links 3 and 4 are connected together by turning pair Q, and by turning pairs B and C to links 2 and 1. Links 5 and 6 are connected together by turning pair P, and by turning pairs D and E to links 2 and 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=A͞B×A͞D-D͞P×B͞Q=A͞C×A͞E-E͞P×C͞Q=const.
$731$LW,GI$