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Ferdinand Berthoud - The Remontoir d'Egalité At The Heart Of The Chronometry

Ferdinand Berthoud The Remontoir d'Egalité At The Heart Of The Chronometry

For the third time, a Ferdinand Berthoud chronometer has been shortlisted for the Grand Prix d’Horlogerie de Genève.

Most of the watches competing at the Grand Prix d’Horlogerie de Genève (GPHG) have a three-hand movement that relies on a traditional escapement, a choice that has proved itself in terms of reliability for over a century.

The Remontoir d'Egalité At The Heart Of The Chronometry

FB 2RE.2 © Ferdinand Berthoud

However, in the Chronometry category in which Chronométrie Ferdinand Berthoud’s FB 2RE.2 model is positioned, over and above reliability, the crucial criterion is accuracy – a quality pursued with passion by master watchmaker Ferdinand Berthoud many years ago, and still the guiding principle in the work of the firm that bears his name.

To achieve the highest levels of chronometric performance, the manufacture has committed itself to several radical technical options. The Chronomètre FB 2RE.2 is the result of a new combination of two regulation mechanisms, making it the only timepiece to benefit from a one-second remontoir d’égalité – and the constant force of a fusee-and-chain mechanism.

The Remontoir d'Egalité At The Heart Of The Chronometry

FB 2RE.2 © Ferdinand Berthoud

The fusee-and-chain system regulates the torque generated by the barrel, keeping it constant irrespective of whether the watch is fully wound or coming to the end of its power reserve. The remontoir d’égalité comes next: positioned at the end of the gear train, it regulates the torque delivered to the escapement. It does so by using a constant force spring, a component very similar to a hairspring: this coils and uncoils, always releasing the same quantity of energy, or torque, as it does so.

The Remontoir d'Egalité At The Heart Of The Chronometry

FB 2RE.2 © Ferdinand Berthoud

This remontoir d’égalité operates in conjunction with the escapement wheel. The latter’s rotation spans a 5-fold cycle, following the oscillations of the balance wheel. During the first 4 oscillations, the remontoire spring uncoils, releasing constant energy. On the 5th oscillation, the triple-shaft stop wheel, which previously prevented the mechanism from coiling back up, is released, allowing the movement to rewind the remontoire spring, which once again begins to release a constant amount of energy for the next 4 oscillations, and so on. The entire cycle lasts one second.

The Remontoir d'Egalité At The Heart Of The Chronometry

FB 2RE.2 © Ferdinand Berthoud

In addition to this remontoir d’égalité , to ensure optimum chronometric performance, the Calibre FB-RE.FC has been fitted with a new, aerodynamic, two-spoke variable-inertia balance wheel, fitted with four balance screws. Its large diameter ensures it maintains inertia and stability, while its low frequency of 18,000 vibrations per hour (2.5 Hz) protects the power reserve.

 

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Chronométrie Ferdinand Berthoud offers a contemporary take on the work of a master watchmaker. Its exclusive timepieces, developed by today’s master watchmakers, are a tribute to the excellence of yesteryear.

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