| 摘要 |
<p>A pedal crank mechanism has a shaft (52) driving a device which converts the cyclically varying force produced by the pedal crank mechanism to constant force which is applied to transmission means for driving the rear wheel of the cycle. A roller (60) is mounted on each crank (22) at a distance from the shaft (52). The roller (60) engages a slot (66) in an L-shaped cam plate (62) pivoted on axis (64) to the cycle frame. Rotation of the pedal crank (22) results in oscillation of the plate (62). To vary the transmission ratio, the position of a link (82) on the plate (62) is controlled by a cable (88) and hand lever (86). The link (82) is connected by rods (88, 90) to pinions (92, 94) engaged by an endless chain (100) engaging the rear wheel pinion (98). The transmission ratio is varied by operating a catch (106) by hand lever (108).</p> |
