This is the first of two patents covering Claudius Blanchard’s BGA Velectrik derailleur (see also French patent # 785,015 Addition 47,985).

One interesting feature of this simple, rod operated, mechanism is that, as the pulley cage is moved inwards a simple angled slot in its bracket also moves it forward - tracking the profile of the freewheel in a simple way. All very simple - but possibly effective.

As an aside, it’s impressive that the St-Étienne patent office was still open at 17:58 on the 1st of February 1935 - a Friday. It seems unlikely that Friday was late opening night, so perhaps those long, lazy, lunch hours necessitated later closing.

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• Publisher: L’Institut national de la propriété industrielle
• Inventor: Claudius Blanchard
• Country: France
• Date: French application February 1935
• Derailleur brands: BGA
• Derailleurs: BGA Velectrik