The drawings included with this patent show a sprung b-knuckle as used on a, single pulley, Campagnolo Sport. The text describes how the same basic spring layout can be used on either knuckle - implying that it is used on the p-knuckle of a Campagnolo Gran Sport, for example.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Tullio Campagnolo
• Country: France
• Date: Italian application November 1952, French application October 1953
• Derailleur brands: Campagnolo
• Derailleurs: Campagnolo Gran Sport, Campagnolo Sport