A work machine includes a frame (2) supported by a plurality of wheels or
tracks (5), at least some of which are associated with respective lifting
columns (32) adapted to raise and lower the frame (2) relative to the
respective wheels or track (5). A work tool is supported by the frame
(2), and a drive mechanism is adapted to rotate the work tool and at
least one of or tracks (5). An articulation apparatus (10) uses a first
actuator (20) and a pivoting support arm (11) to move one of the wheels
or tracks (5) between a projecting position and a retracted position
relative to the frame (2). The articulation apparatus (10) includes a
second actuator (21) adaped to rotate the wheel or track (5) about a
vertical axis (Z).