Actuation device for a control cable for a bicycle gearshift

An integrated brake-gearshift actuation device of a bicycle, comprising an actuation device for a bicycle brake and an actuation device for a control cable for a bicycle gearshift, the actuation device for a control cable comprising:

• a casing configured for mounting on a bicycle handlebar;
• a cable-winding bush that is contained in the casing and is angularly mobile about a main axis (A);
• an indexing bush that is coaxial with the cable-winding bush and holds the cable-winding bush in predetermined angularly spaced positions having predetermined indexing angles (α) that correspond to specific positions of a transmission chain relative to toothed wheels;
• a control lever that rotates the cable-winding bush in a first angular direction about the main axis (A) to obtain an upward gearshift;
• and,
• a coupling that mates the cable-winding bush and the indexing bush and has a predetermined circumferential clearance between the cable-winding bush and the indexing bush which corresponds to a predetermined gearshifting extra-stroke angle (β) that is less than a minimum angle of the predetermined indexing angles (α),
• the lever comprises at least a first gearshift lever, which is angularly mobile with respect to the casing about the main axis (A) of the device, in the first angular direction starting from a neutral position to obtain the upward gearshifting,
• and the first gearshift lever acts on the cable-winding bush to:
• (i) impose a first rotation of the cable-winding bush with respect to the casing and to the indexing bush in the first angular direction by the predetermined gearshifting extra-stroke angle (β);
• (ii) impose a second rotation of the cable-winding bush with respect to the casing, together with the indexing bush, in the first angular direction by the respective predetermined indexing angle (α);
• and,
• (iii) impose a third rotation of the cable-winding bush with respect to the casing and to the indexing bush in a second angular direction opposite to the first angular direction by the predetermined gearshifting extra-stroke angle (β), and
• the lever comprises a second gearshift lever, which causes the indexing bush to rotate together with the cable-winding bush, in a second angular direction about the main axis (A) of the device, so as to obtain a downward gearshifting,
• wherein:
• the cable-winding bush comprises a rotation pin arranged along the main axis (A) of the device;
• and
• the coupling between the cable-winding bush and the indexing bush comprises at least one protrusion, protruding radially from the rotation pin, and at least one corresponding recess, formed radially in the indexing bush, wherein the predetermined circumferential clearance is provided between the at least one recess and the at least one protrusion.