A linkage arrangement for an active anti-tip system is provided for
improving the stability of a powered vehicle, such as a powered
wheelchair. The vehicle includes a drive-train assembly which is
pivotally mounted to a main structural frame. A suspension system biases
the drive-train assembly and its connected anti-tip wheel to a
predetermined resting position. The drive-train assembly bi-directionally
rotates about a pivot in response to torque applied to or acceleration
forces on the vehicle. The linkage arrangement is characterized by a
suspension arm pivotally mounting to the main structural frame about a
pivot at one end thereof and an anti-tip wheel at the other end. The
linkage further includes at least one link operable to transfer the
bi-directional displacement of the drive-train assembly to the suspension
arm and may also include a bell crank link member.