Patent ID: 7597167

Claim:
A snowmobile, comprising: an engine configured to rotate a drive shaft; a track belt comprising an inner surface having a first track portion with a plurality of driven projections at regular intervals along a direction of movement of the track belt, and a second track portion with a plurality of driven windows at regular intervals along the direction of movement of the track belt; a slide rail configured to apply pressure to the inner surface of the track belt to press the track belt against a riding surface; a drive mechanism comprising: a first drive sprocket portion having a projection drive portion including one or more members for engaging the driven projections, the first drive sprocket portion being coupled with the drive shaft; and a second drive sprocket portion having a window drive portion for engaging an edge of the driven windows, the second drive sprocket portion being coupled with the drive shaft; wherein the driven projections, the driven windows, the projection drive portion, and the window drive portion are positioned so that the time when the driven projections and the projection drive portion initially engage each other is different from the time when the edge of the driven window and the window drive portion initially engage each other.