A motor-assisted single-wheel cart is provided with a motor for generating an assisting power in response to an operation force when operating an operation handle by a human hand, and a power transmission mechanism for transmitting an output of the motor to an axle. The motor is arranged rearwardly upwardly...http://www.google.de/patents/US6173799?utm_source=gb-gplus-sharePatent US6173799 - Motor-assisted single-wheel cart
