This 1950 patent, and its younger brother, French Patent # 1,040,852, are startling in their very modernity. It doesn't take too much imagination to visualise a SRAM Red eTap or Shimano Dura-Ace Di2 lovingly threaded into that gear hanger.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Tullio Campagnolo
• Country: France
• Date: Italian application December 1950, French application May 1951
• Derailleur brands: Campagnolo
• Derailleurs: none - or possibly nearly every single one!