I am not entirely sure what is going on with the other parts of this derailleur design - but this is the first appearance of a design of pulley cage that Simplex used again and again on their touring derailleurs.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Lucien Juy
• Country: France
• Date: French application June 1935
• Derailleur brands: Simplex
• Derailleurs: Simplex Route