Abstract: In order to immobilize the small rear wheels of a motorized chair during transit of the chair and occupant in a van or other conveyance, the chair is backed into the device and a lever is shifted by the occupant. The lever is connected to a linkage train including an overcenter toggle linkage and a pair of arcuate wheel clamping plates spaced apart to overlie the rear wheels. In one position of the lever, the plates clamp down on the wheels and lock the wheels in place. In the other position of the lever, the wheels are disengaged and allow the chair to move out.