| CPC B62M 3/04 (2013.01) [B62M 1/36 (2013.01); B62M 11/02 (2013.01); B62M 3/003 (2013.01)] | 8 Claims |

|
1. A crank apparatus, comprising:
a crank mechanism comprising a crank, an axle-end gear arranged at one end of the crank and a pedal-end gear arranged at another end of the crank;
a transmission mechanism arranged at an internal of the crank, and comprising a rotating axle, a first gear and a second gear, the rotating axle comprising a first end and a second end, the first gear connected to the first end and engaged with the axle-end gear for transmission, the second gear connected to the second end and engaged with the pedal-end gear for transmission, at least one circular groove formed at the first end and the second end;
at least one supporting module adapted to sheathe the first end of the rotating axle and at least one supporting module adapted to sheathe the second end of the rotating axle, each one of the supporting modules comprising an outer ring and a plurality of rollers, each one of the rollers received inside a respective one of the circular grooves and clamped between the rotating axle and the outer ring; and
a rotating arm module comprising a first rotating arm and a second rotating arm, one end of the second rotating arm connected to the first rotating arm, another end of the second rotating arm connected to the pedal-end gear;
wherein the axle-end gear comprises an inner bushing, a helical gear and a roller bearing, the crank comprises an outer housing and an inner housing correspondingly attached to the outer housing, the outer housing comprises a cylindrical column, the inner bushing is adapted to sheathe the cylindrical column, the helical gear is adapted to sheathe the inner bushing, the roller bearing is adapted to sheathe the helical gear and be clamped by the inner housing and the helical gear jointly.
|