Bicycle gearshift with improved precision control

Abstract

The present invention refers to a bicycle gearshift with improved precision control, comprising a kinematic mechanism in the form of a four-bar linkage with a base body and a mobile body connected together through a pair of connecting rods articulated to the base body and to the mobile body at four pin elements, each pair of opposite pin elements of the four pin elements defining a diagonal of the four-bar linkage kinematic mechanism, and a first attachment group of the base body to a bicycle frame, the mobile body being connected to a chain guide at a second attachment group, the four-bar linkage kinematic mechanism being associated with gearshift actuation means suitable for deforming the four-bar linkage kinematic mechanism so as to determine a displacement of the mobile body with respect to the base body and consequently a primary displacement of the chain guide in the axial direction with respect to the axis (A) of a cogset, and it is characterised in that the first attachment group comprises a kinematic mechanism for changing the relative angular position between the base body of the four-bar linkage kinematic mechanism and the frame as a function of the primary displacement of the chain guide.