French Patent # 813,241 - Huret

French Patent 813,241 - Huret main image

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.