Patent ID: 8783392

Claim:
A tracked mobility device, comprising: a) a frame supporting a seat; b) a pair of track drives connected to said frame, with each track drive comprising a powered center drive wheel, a front roller, a rear roller, and a flexible track; wherein said center drive wheel has a first diameter, said front roller has a second diameter, and said rear roller has a third diameter, wherein said center drive wheel diameter is at least 20% greater than either said front roller diameter or said rear roller diameter; c) a rear wheel assembly connected to said frame and comprising three wheels sharing a common axle, said rear wheel assembly comprising a center wheel having a center wheel diameter, a first outer wheel having a diameter at least 10% smaller than said center wheel diameter, and a second outer wheel having a diameter at least 10% smaller than said center wheel diameter; and d) a controller effective for controlling the speed and direction of rotation of each of the track drives.