BELT DRIVING APPARATUS FOR BICYCLE

摘要

A belt drive apparatus for a bicycle comprises a driving gear (14A) having external gear teeth (14a) coupled by a toothed belt (15) to a gear 17 on the rear wheel of the bicycle, and an inner gear (14B) coaxial with and secured to the driving gear (14A) and having external gear teeth (14b), and an annular crank gear (10) mounted on the crank shaft (12) and driven by the pedal crank (11). Crank gear (10) has internal gear teeth and encircles and meshes with inner gear (14B). In a modified construction an eccentricity control element controls the locus of movement of the gears 14A, 14B about the axis of the crank shaft 12.