This patent details Tullio Campagnolo's attempts to devise a chain more suited to derailleur gear changing. As an aside, by the late 1940s he also had an early interest in shaping the teeth on the sprockets. These issues have obsessed derailleur designers throughout history.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Tullio Campagnolo
• Country: France
• Date: Italian application May 1946, French application May 1947
• Derailleur brands: Campagnolo
• Derailleurs: none