French Patent # 2,563,176 - Simplex

French Patent 2,563,176 - Simplex main image

This patent covers Simplex's 'modernised' p-knuckle design that has a concealed p-pivot bolt. You can see this in action on the Simplex 440 and Simplex 640.

It all looks pretty dull, but there is a, vaguely interesting, story here.

The style of having a p-knuckle with a concealed p-pivot bolt is generally thought of as being part of Shimano's assumption of world dominance. During the 1980s Shimano redefined the rear derailleur. Indexing, stylish paint finishes and a smooth aero look that included a concealed p-pivot bolt - they were all seen as components of Shimano's irresistable tsunami of innovation. The first Shimano derailleur to have a concealed p-pivot was the achingly beautiful 1986 Shimano Santé. But this patent, held by ugly, uncool, Simplex dates from 1984. Interesting!