Patent ID: 7726689

Claim:
A powered wheelchair-comprising: a frame; a seat mounted on the frame; a pair of drive wheels positioned on opposing sides of the frame; a drive motor operatively coupled to at least one of the drive wheels for powering rotation of the drive wheel about a drive wheel axis and for powering movement of the wheelchair across a ground plane; and at least one anti-tip assembly comprising a suspension arm pivotably mounted to the frame at a suspension arm pivot axis, said suspension arm extending from said suspension arm pivot axis outwardly from the frame, said suspension arm pivot axis vertically spaced above the ground plane, and an anti-tip wheel assembly including an anti-tip wheel-having a rotational axis about which the anti-tip wheel rotates, said anti-tip wheel assembly disposed proximate the extended end of the suspension arm, the vertical position of the suspension arm pivot axis with respect to the ground plane in normal operation being spaced from and positioned relatively below a line drawn between the drive wheel axis and the rotational axis of the anti-tip wheel; and means for operatively connecting the drive motor to the suspension arm, wherein the suspension arm pivots about the suspension arm pivot axis in response to torque created by the rotation of the drive wheel and causing a corresponding vertical movement of the anti-tip assembly.