Special Section on Recent Development of Electromechanical Devices(Selected Papers from IS-EMD2007)

The linkage mechanism between the front and the rear wheels of a farming implement includes a front and a rear arm the free ends of which suspend the respective wheels. Each arm has a transverse bracket near its other end. The bracket defines, at its free end, a pivot joint of a normally generally horizontal connecting rod whose other end is similarly connected to the bracket of the other arm. Each arm is mounted in a respective bearing for swinging about a point to raise or to lower the frame of the implement. The three pivot points associated with each arm define a respective linkage triangle. The geometry of the linkage triangles is developed from a reference triangle, divided by a median into two triangles of which one corresponds to one of the linkage triangles and the other corresponds to or is similar to the other one of said linkage triangles. The invention facilitates the designing of the linkage.