This patent for a parallelogram derailleur was granted to the unknown Francesco Ghiggini. In 1951 Ghiggini sold this patent to Tullio Campagnolo, prompting specualtion that Ghiggini's design inspired Tullio Campagnolo to develope the iconic Campagnolo Gran Sport.

Ghiggini's design is not immediately similar to that of the Campagnolo Gran Sport (patented in 1950) - but has a more striking similarity to Tullio Campagnolo's 1951 patent of an early prototype of the single pulley Campagnolo Sport.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Francesco Ghiggini
• Country: France
• Date: Italian application November 1941, French application December 1948
• Derailleur brands: Campagnolo
• Derailleurs: Campagnolo Gran Sport!