Patent ID: 7581605

Claim:
A vehicle comprising: a vehicle body having a first axis near a first end of the body and a second axis near a second end of the body; a first pair of track arms mounted for rotation about the first axis, wherein a length of the first pair of track arms is adjustable with a first range; a first pair of tracks each mounted for rotation about one of the first pair of track arms, wherein the first pair of tracks is sufficiently elastic to compensate for adjustments of the length of the first pair of track arms within the first range; a second pair of track arms mounted for rotation about the second axis, each of the second pair of track arms extending from the second axis more than half the distance to the first axis and rotatable through a point of rotation nearest to the first axis; a second pair of tracks each mounted for rotation about one of the second pair of track arms; and a control system selectively rotating the first and second pairs of tracks to move and turn the vehicle in forward and reverse directions and selectively rotating the first and second pairs of track arms about the first and second axes respectively.