Patent attributes
A stair climbing device, adapted for a wheel chair, including at least one climbing element which is adapted to be moved on a circular path so that it can get in contact with the next step of a stair and lift or lower the stair climbing device on the next step. The stair climbing device includes a drive motor for providing a driving force for moving the at least one climbing element on the circular path, wherein the movement of the at least one climbing element on the circular path is carried out with a non-constant rotational speed. A gear transmission assembly is provided between the drive motor and the at least one climbing element which gear transmission assembly is adapted to cyclically vary the rotational speed of the at least one climbing element with respect to the rotational speed of the drive motor.