This patent is for pulley wheels that have some ability to run at a slight angle. This was all part of a widespread concern, in the early 1950s, about the ‘problems’ that were expected to be caused by the excessive width of 5 speed freewheels.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Albert Raimond
• Country: France
• Date: French application October 1952
• Derailleur brands: Cyclo
• Derailleurs: unknown