Track drive device for all terrain vehicle

Track drive device for all terrain vehicle comprising a frame able to be mounted on the side of a vehicle chassis and carrying two main wheels and support wheels around which is wound the track, characterised in that the frame (14) comprises a rear part (16) able to be fixed to the chassis (C) of the vehicle and carrying one (38) of the main wheels, and a front part produced in the form of an approximately horizontal oscillating beam (18) bearing the other main wheel (42) and at least one (40D, 40E) of the support wheels and mounted pivoting on the rear part (16) about a first transverse pivot (20) located at a lower lever, and in that an approximately horizontal suspension arm (52) is also provided arranged above the oscillating beam (18) and linked to the latter by a connecting rod (64) and mounted pivoting about a second transverse pivot (24) arranged at an upper level approximately at the height of the chassis, wherein the suspension arm (52) has a front end linked to the chassis (C) via a suspension element (58), and wherein the front end (56) of the suspension arm (52) comprises a plate (60) in which is arranged a window (62) and in that the suspension element (62) is a leaf suspension fixed transversely below chassis (C) and one end of which is held in the said window (62).