French Patent # 1,087,957 - Campagnolo

French Patent 1,087,957 - Campagnolo main image

I don’t fully understand how this derailleur design is supposed to work. It only seems to have one of the two required parallelogram plates.

I do fully understand that this patent starts to clarify the link between Tullio Campagnolo and Marcello Gambato - the main man at Gian Robert. Clearly Marcello Gambato worked for Tullio Campagnolo in some capacity, and while doing so developed a number of features that were typical of his early designs for Gian Robert. The rear knuckle with its distinctive adjustment screw and the pulley cage with its distinctive tension spring are obvious examples.