This patent shows the Tarf derailleur of 1942. It is a pretty tidy item - small, neat and with a rather modern-looking offset pulley cage. It could make a very reasonable claim to be amongst the most advanced racing derailleurs available in 1942.

I particularly like the 'cross-bar' built into the toggle chain to stop it retracting if the cable breaks.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Piero Taruffi
• Country: France
• Date: Priority date February 1942
• Derailleur brands: Tarf
• Derailleurs: Tarf