This patent describes a single pulley derailleur that uses a cog-based operating mechanism - echoing the Westminster design in French Patent 785,604.

In Huret's design the cog mechanism seems to be driven by a rigid cable that can transmit torque, a bit like the cables that Huret later used to drive its speedometers. This contraption was marketed as the Huret Course Pro.

I believe that derailleurs to this design were manufactured for Huret by Chaluret.

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• Publisher: L’Institut national de la propriété industrielle
• Inventor: André Huret
• Country: France
• Date: French application November 1936
• Derailleur brands: Huret, Chaluret
• Derailleurs: Huret Course Pro (1st style)