The commercial and sporting success of fork type derailleurs such as the Nieddu’s Vittoria Margherita and Oscar Egg’s Super Champion led to a blind panic by French derailleur designers to get a slice of the action. Lucien Juy was no exception, and unleashed a barrage of patents for fork derailleurs and the chain tensioning mechanisms that they required. This is the first of many.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Lucien Juy
• Country: France
• Date: French application September 1933
• Derailleur brands: Simplex
• Derailleurs: Super Simplex