| 摘要 |
PURPOSE:To achieve drastic increase in driving power by sandwiching an eccentric step difference double gear between an inner chain stay and an outer chain stay between a large gear and a free wheel, and whereby mounting the double gear on a common shaft rotatively. CONSTITUTION:An eccentric step difference double gear comprising a base gear 12 having teeth half as much as those of the large gear 5 and a front eccentric small gear 13 having teeth one or two less than those of the base gear, in front thereof, is sandwiched between inner chain stay 17 and an outer chain stay 18 that are formed in the middle of a conventional large gear 5 having the even number of teeth and a free wheel 10, and the double gear is mounted on a common shaft 14 rotatively. The large gear 5 and the base gear 12 are connected together by a front chain 15, while the free wheel 10 and the front eccentric small gear 13 are connected together by a rear chain 16. A fixed plate 19 on which a pulley guide 21 is pivotally supported the front end, is fixed to a free wheel shaft 11, and adjustment of the tension of the chain 16 is carried out thereby. |
