| 摘要 |
A drive mechanism for pedal powered vehicles including at least two unitary pulleys, each having at least one circular receiving groove, and a ribbed drive cord held in tension in the grooves of each of the two unitary pulleys. These pulleys may be made of plastic, as by injection molding. The pulleys may include a number of tiered circular grooves on the tiered layers of the pulley. A conventional derailleur may be used to change gears.
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