Crank drive for bicycles etc. has two pedals with bars not connected to common shaft but born inside each other for relative turning inside bottom bracket bearing

摘要

The pedal bars of the crank drive are not connected to a common shaft, but are born side each other, so that they can turn against each other and inside the bottom bracket bearing. One of the pedal bars has a crankshaft on the side opposite side of the bearing, e.g. the same side as the other pedal bar. The crankshaft extends in the same direction as, and parallel to, the pedal bar. A second bearing is located on an eccentric around the bottom bracket bearing, and carries a turnable ring. One or more chain rings are fastened to the ring.