The 1950s were the golden years of the Spirax brand - but Raymond Bon renewed his trademark in 1981. He applied for his first derailleur patent in 1935, so he would probably been over 70 years old when he made this application.

His address is given as Andresy 35km north west of Paris.

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• Publisher: L’Institut national de la propriété industrielle
• Inventor: Raymond Bon
• Country: France
• Date: French application April 1981
• Derailleur brands: Spirax
• Derailleurs: none