This patent looks as though it covers a proposed development of MAVIC's signature 800/850 design. It includes a couple of interesting features:

• The parallelogram plates have a distinctive 'V' shape that is very reminiscent of designs that Shimano used on its ATB derailleurs many decades later.
• The b-pivot has an offset mounting bolt which, this time, is remiscent of a Gian Robert derailleur.

If this design had ever been manufactured, it would have been a natty looking piece of kit.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Georges Bloy
• Country: France
• Date: Priority date May 1981
• Derailleur brands: MAVIC
• Derailleurs: unknown