The lengths of the links comply with the conditions: A͞F=A͞C=G͞K=G͞D, E͞C=E͞D=E͞K=E͞F=A͞C/2 and H͞K=H͞F=B͞C=B͞D=C͞E/2. Figures GKED, AFEC, HKEF and BDEC are rhomboid linkages. Axis Ea, parallel to straight line ABC, is the axis of mirror symmetry of the upper and lower halves of the mechanism. Link 1 turns about fixed axis A and is connected by turning pairs F to links 6 and 7. Link 3 turns about fixed axis B and is connected by turning pairs D to links 5 and 9. Links 5, 6 and 8 are connected by turning pairs E to link 4 which turns about fixed axis C. Link 2 is connected by turning pairs G, H and K to links 9, 7 and 8 . When link 1 turns about axis A, link 2 has rectilinear translation in a direction perpendicular to line ABC.
$729$LW,GI$