Patent ID: 8061233

Claim:
Actuation device for a control cable for a bicycle derailleur, comprising: a casing, attachable to a handlebar of the bicycle, a cable-winding drum, angularly mobile in the casing about a main axis of the device, at least one actuator, active on the drum to rotate it in a first and in a second angular direction about the main axis of the device, an indexer to releasably hold the drum in predetermined angular positions, against a return action, in the second angular direction, exerted by a biasing member, wherein said indexer comprises: a first rotary member integral in rotation with the drum and a second stationary member integral with the casing, wherein one of the first and the second members is provided with a pointer engaged on a hooking outline formed on the other member, the hooking outline comprising a plurality of stop positions corresponding to the predetermined angular positions of the drum and a plurality of free sliding paths, interspaced between stop positions, having a circumferential free sliding section and an inclined sliding section, wherein the shape and the location of the stop positions and of the free sliding paths are such that the rotation of the drum in the second angular direction provides an active initial movement step, wherein the rotary member can only move if forced in rotation by the at least one actuator so that the pointer is taken to disengage from a stop position, and an automatic final movement step, wherein the rotary member is free to rotate in the second direction without the need for further action by the actuator, with the pointer that runs along the free sliding path that follows a stop position from which it has been disengaged to a subsequent stop position.