Patent ID: 6830259
Filing Date: 2004-12-14
Classification: B62M

Abstract:
A driving device suitable for a bicycle, said driving device comprising:a main shaft having first and second ends and rotatable about a central axis thereof; a chain sprocket adapted for mounting about said main shaft in a coaxial manner for rotation therewith, said chain sprocket being engageable with a chain to drive a wheel of said bicycle; and two power transmission units each of which is mounted at a respective one of said first and second ends of said main shaft, each of said transmission units comprising a non-rotating first sprocket connectible to an adjacent support structure of the bicycle during use of the driving device, a rotatable, planetary, second sprocket spaced radially outwardly from the first sprocket, a pedal, a crank connecting said pedal to said second sprocket, a flexible, continuous drive member extending around and between said first and second sprockets and adapted to engage said second sprocket, a sprocket supporting member fixedly attached to a respective one of said ends of the main shaft and attached to and supporting said second sprocket so as to allow rotation of said second sprocket relative to said supporting member by means of said continuous drive member, wherein said chain sprocket is adapted for mounting on one of said power transmission units for rotation with the sprocket supporting member of said one power transmission unit and wherein the distance of each pedal from said central axis varies substantially as the pedals are moved relative to said central axis during use of said driving device and said pedals and their attached cranks are able to provide greater rotational torque to said main shaft during a driving phase of their respective rotations when each pedal is at a greater distance from said central axis.