A roller is disposed rotatably on a roller shaft of a scooter, and has a housing which includes two housing halves that are interconnected to define an accommodation chamber therebetween. The housing halves define two shaft holes to permit extension of the roller shaft. A light-permeable rim element...http://www.google.fr/patents/US6337528?utm_source=gb-gplus-shareBrevet US6337528 - Roller with self-contained generator device
