| 摘要 |
A drive mechanism is disclosed for driving the chain of a bicycle, motorbike or the like, including a sprocket gear adapted for rotatable connection at its center with the vehicle frame, the sprocket gear periphery including a pair of diametrically opposed portions of corresponding cycloid configuration, and a pair of foot pedal crank arms connected with, and extending diametrically outwardly from the center of, the sprocket gear, the crank arms being angularly advanced, relative to the minor axis of the sprocket gear, in the power supplying direction of rotation by an angle of from about 30 DEG to about 40 DEG . In one modification, the cycloid portions are spaced in the direction of the minor axis of the sprocket gear, the adjacent ends of the cycloid surfaces being joined by tangentially arranged arcs of a circle the diameter of which equals the length of the major axis of the cycloid. In order to provide change speed gearing capability, a second corresponding sprocket gear of different size may be connected adjacent and coaxially with the first sprocket gear. |
