Patent 7255660 was granted and assigned to Campagnolo on August, 2007 by the United States Patent and Trademark Office.
A bicycle gear-shift actuator having an articulated quadrilateral support with four connecting rods hinged together by four pin elements, and a motor member, having a variable length output shaft that travels along a drive axis between two opposite pin elements to move them for deforming the articulated quadrilateral. Preferably, the drive axis perfectly intersects the pin axis of at least one of the two pin elements.