Abstract: A power transmission device having at least two one-way clutches is used to transmit the driving force of the power generator to the right and left drive wheels. By this power transmission device, it is possible to transmit the driving force of the power generator to the right and left drive wheels almost half and half when the wheel contact load are the same. While if the drive wheels rotate at a different speed, hardly any driving force is transmitted to the side of the drive wheel which can rotate faster and the driving force is mainly transmitted to the wheel rotates slowly. Accordingly, it is possible to transmit the power without fail to the drive wheel which touches the ground even when the transportation device is curving or slipping, or when one of the wheels parts from the ground.

Abstract: The stand-up transportation device according to this invention comprises the shafts to which the front wheel and the rear wheel are assembled respectively, and the frame connecting these shafts. This transportation device also has the drive equipment that can drive the wheels on the shafts. Therefore, the user can run on a plane, an ascending slope or a rough road standing on the frame of this automatic transportation device as when they rides on a snowboard and the like, and changing the course by shifting the weight. As the transportation device is made of the shafts and the frame combined in a simple way, the user can readily enjoy riding on it at any time and anywhere. And the user can enjoy the drive feeling as they ride on a snowboard and the like without snow. Also, they can enjoy riding on it for a long distance or time.

Abstract: The transportation device according to this invention has the brake device that is released when the control lever is held. Thus the brake device can be used to stop the transportation device and as a parking brake. The transportation device according to this invention is safe because it does not start unless the control lever is operated. If the user, while running the transportation device in a wasteland and the like, is thrown out of the transportation device and releases the control lever, the brake functions automatically and the engine output decreases. Thus the transportation device can be stopped without fail, and dose not run uncontrollably.