Patent ID: 6907945

Claim:
A wheel chair capable of going over an obstacle or ascending or descending a stair, the wheelchair comprising: a wheel frame having a seat on which a user sits; an actuator coupled to the wheel frame for supplying driving force; a power generating unit having a main shaft coupled to the actuator; a first transmission having a sun gear fixed to the main shaft, a plurality of planet gears meshed with the sun gear and rotating or revolving in accordance with applied load, a ring gear meshed with the respective planet gears, and carrier coupled to the respective planet gears and rotated by the planet gears; a second transmission having a driving shaft meshed with the ring gear of the first transmission, a key frame rotatably installed on the driving shaft, coupled to the carrier, and serving as a role of a center shaft during a step operation, and a casing fixed to the key frame; a plurality of front wheels each coupled to the driving shaft of the second transmission and fixed to rotating shafts each rotatably fixed to the casing; a follower directly drivingly coupled to the power generating unit, and having a follower shaft to which the wheel frame is fixed; and a rear wheel fixed to an end of the follower shaft of the follower.