Patent ID: 8469465

Claim:
An undercarriage comprising: a main frame; a track frame assembly mounted to the main frame for pivoting vertically; an idler bogie arm pivotally attached to the track frame assembly for moving vertically; an idler rotationally attached to the idler bogie arm; a roller bogie arm pivotally attached to the track frame assembly; a minor bogie arm pivotally attached to the roller bogie arm; a roller rotationally attached to the minor roller bogie arm; a drive sprocket located in fore-and-aft alignment with the track frame assembly and being fixed to the main frame for rotation about a sprocket axis of rotation; and a fixed track roller being in fore-and-aft alignment with, and being located adjacent to, the drive sprocket and rotationally attached to an axe rigidly mounted to the track frame, the fixed track roller having an outer radius overlapping an outer radius of the drive sprocket and being located for at least partially supporting a weight of the track frame assembly.