| 摘要 |
A combined handlebar-mounted assembly of a gear-operating lever (10) and brake-operating lever (12) permits bicycle gears to be changed to a lower ratio by pulling lever (10) away from lever (12) and to a higher ratio by pushing lever (10) into the channel-shaped back of lever (12). If lever (12) is pulled to apply the brake, the gear ratio is unchanged. One mechanism for achieving this uses brake-operating lever axis (32) to journal a gear-operating wire wind-up drum (33) carrying ratchet teeth (33C) controlled by escapement pawl (36). Gear-operating lever (10) is pivoted on support member (31), itself also pivoted at 32. Pulling lever (10) away from lever (12) first tilts lever (10) about its support member pivot axis and then causes a serrated end (27) of lever (10) to engage drum periphery (33A) whereafter the support member (31) and lever (10) pivot together about axis (32) to move the drum one wind-up unit, manually one tooth. Pushing lever (10) towards lever (12) causes it to abut at 31d and tilt the support (31) anticlockwise, so that projection (34) frees the escapement pawl (36) to allow the ratcheted drum (33) to revolve. Pulling lever (12) inwards pivots the whole internal assembly at 32; the lever (10) is still in essentially unchanged relative position to the drum serrations (33A) and abutment (31D) so that no gear change takes place. |
