| 摘要 |
The actuation device (100) comprising a casing (101), a bobbin (112) on which to wind the cable (K), a drive mechanism (130) and indexing means (113) to removably hold the bobbin (112) in predetermined angular positions. The drive mechanism (130) comprises a lever (131), angularly mobile with respect to the casing (101) from a neutral position to obtain downward or upward gearshifting, an internally toothed crown (114), non rotatably mounted to the bobbin (112) and angularly mobile with it in the casing (101), a ratchet mechanism (140) between the lever (131) and the toothed crown (114) and elastic means (133) acting between the lever (131) and the casing (101), which tend to take the lever (131) back into the neutral position. The ratchet mechanism (140) comprises two opposite rocker arms (141, 142), a toothed sector (147, 148) formed on each rocker arm (141, 142) and having a toothing profile suitable for engaging with the toothing of the toothed crown (114), a cam profile (151, 152) formed on each rocker arm (141, 142), a thruster (161) to thrust each rocker arm (141, 142) in the direction to thrust the toothed sectors (147, 148) towards the toothed crown (114), a pointer (160) stationary with respect to the casing (101) and engaged with at least one of the rocker arms (141, 142), on its cam profile (151, 152). The cam profile (151, 152) is configured so that, when the pointer (160) is engaged with the cam profile (151, 152) of a rocker arm (141, 142), the toothed sector (147, 148) of the same rocker arm (141, 142) is held away from the toothed crown (114), when the pointer (160) is disengaged from the cam profile (151, 152), the toothed sector (147, 148) of the same rocker arm (141, 142) is thrusted into engagement with the toothed crown (114) by the thruster (160). |
