The lengths of the links comply with the conditions: O͞A=A͞B=M͞N=Q͞P, A͞M=P͞N=O͞N=M͞Q=M͞D=O͞Asqrt(2) and P͞B= 2O͞A. Figures MNPQ, ONPB and ONMA are crossed-crank, rhomboid and parallel-crank linkages, respectively. Link 1 turns about fixed axis A and is connected by turning pairs M to links 3 and 7. Link 2 turns about fixed axis 0 and is connected by turning pairs N to links 3 and 4. Link 5 turns about fixed axis B and is connected by turning pairs P to links 4 and 6. When link 1 turns about axis A, point Q describes straight line Aa which is perpendicular to straight line OAB and passes through point A. Point D describes straight line Ab which coincides with line OAB. The points of link 7 describe ellipses.
$711$LW,GI$