The lengths of the links comply with the conditions: F͞E=B͞C and B͞F=C͞E. Worm 1 turns about axis A of the wagon frame and meshes with segment gear a of link 3 which is part of four-bar linkage KHGC. Link 5 of parallel-crank linkage CEFB is connected by turning pairs E and F to links 2 and 4 to which wheels d are rigidly attached. Wheels d are turned about axes B and C of the wagon frame by turning worm 1 about axis A.
$1784$GL,FD$