This addition to French Patent # 669,030, dated 1934, describes Simplex Champion de France 35.

This, rather individual, derailleur acquired an extravagantly cut away pulley cage/chain guide and a curious wing bolt for attaching the pulley wheel - both of which bear little resemblance to anything that Simplex produced before or since.

This derailleur does show one very significant innovation that lives on in the majority of derailleurs produced today. The humble hanger plate appears here in a recognisable form for the very first time.

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• Publisher: L’Institut national de la propriété industrielle
• Inventor: Lucien Juy
• Country: France
• Date: French application July 1934
• Derailleur brands: Simplex
• Derailleurs: Simplex Champion de France 35