Here, Henry Juy, the CEO of Simplex, emulates his father, Lucien Juy, who had a penchant for patenting designs that looked suspiciously like those of his main competitors. This, cam-operated, indexed derailleur (with a vaguely ludicrous spring system) is redolant of the Huret Commander (12913) and of the even earlier Bridgestone Synchro Memory Shift. If you can't beat 'em, patent-the-hell outa-them.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Henry Juy for Etablissement Le Simplex SARL
• Country: France
• Date: Priority date November 1984
• Derailleur brands: Simplex
• Derailleurs: none