This is the first of three patents that lead up to the design of the 1950 Selectic derailleur. This derailleur was a 3-speed device with no lever or cable - you operate the derailleur by back-pedalling.

This first patent, from 1940, describes a single pulley device. The patent lists the inventor as Ange Henri Le Beguec of Rennes, France.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Ange Henri Le Beguec
• Country: France
• Date: Priority date December 1940
• Derailleur brands: Selectic
• Derailleurs: a very early version of the Selectic