1999 - Constant Escapement

Constant force escapement with bending blade in the frame. Rolex company filed patents on behalf of inventor Nicolas Déhon for this design in 1999.
Nicolas Déhon, who joined Rolex in 1997, was responsible for the project E.L.F: Échappement-Lame-Flambage (Escapement-Blade-Buckle).

It began with a journey during which Nicolas Déhon began to bend a rigid cardboard train ticket. He realized that such a deflection and return move could potentially be used to generate and store energy in the escapement.

Working at Rolex, he built 20 prototypes of a bending blade escapement, which was then still made of Nivarox steel. Unfortunately, none of them worked properly. The main problem was the geometry of the structure. The condition for correct operation had to be an ideal collinearity of two opposite points, where the bending blade was fixed to the frame. If these two points were not on one straight line, the escapement could not work.

No prototypes met this collinearity because both the blade and the frame were not made of a single element. This was one of the main reasons why the prototypes did not work. 

It was only silicon and the technology associated with it that opened a new possibilities for this solution, which Nicolas Déhon continued under Girard-Perregaux Company.

See: 2008 - Constant-Force Escapement with "buckling" silicon blade

Notifier: Tomasz Jakubas
Other records: Timeline of Watchmaking Innovations