Patent ID: 7670251

Claim:
A bicycle hub gearbox comprising: a first planetary gear mechanism; a second planetary gear mechanism operatively coupled with the first planetary gear mechanism; a braking mechanism selectively coupled to the first planetary gear mechanism; and a clutch mechanism selectively coupling an output side of the first planetary gear mechanism to an input side of the second planetary gear mechanism to selectively transmit either a driving torque applied by a rider in a driving direction depending on a selected gear ratio or a braking torque applied by the rider in a braking direction to the braking mechanism independent of a selected gear ratio via one path, the clutch mechanism including a ring gear with ring teeth engaged with a planet gear of the first planetary gear mechanism, and a toothed ring arrangement that is offset in an axial direction from the ring teeth, a linking member having a part selectively connected to the second planetary gear mechanism, a first toothed ring part of the linking member selectively engaged with a first toothed ring part of the toothed ring arrangement of the ring gear, a second toothed ring part on the output side of the clutch mechanism, a driving pawl and a braking pawl active in opposite rotational directions, with the driving pawl and the braking pawl being disposed on an output side part of a planet gear carrier of the first planetary gear mechanism, the first toothed ring part of the ring gear having a plurality of recesses arranged in a circumferential direction, and the first toothed ring part of the linking member having a plurality of projections located in the recesses, with the recesses and the projections being configured with circumferential spacings therebetween to provide a limited range of relative circumferential rotation between the linking member and the ring gear.