F.P. Journe: Chronomètre à Résonance 2020

The Chronomètre à Résonance is the watch that fully defines the creativity and vocation of F.P. Journe. Unveiled for the first time in 2000, in twenty years it has been declined by the Master watchmaker in several versions, starting with the Souscription, made to order for customers who had purchased the first watch by F.P. Journe, the Tourbillon Souscription.

It couldn’t be otherwise. The Master is too curious and too brilliant not to be stimulated to work on one of the most fascinating phenomena of physics, which has important implications in watchmaking: resonance. On which it is worth spending a few words before dealing with the Chronomètre à Résonance with platinum case, created by F.P. Journe.

WHAT IS RESONANCE

The phenomenon of resonance began to be noticed with the invention of the pendulum. In the 17th century, the Dutch physicist and mathematician Christiaan Huygens observed that, by placing two pendulums side by side and on the same wall, they tended to synchronize their own oscillatory movement: each made the other resonate at its own frequency.

Any animated element transmits a vibration to its environment. When another element picks up this vibration, it absorbs its energy and begins to vibrate at the same frequency. The first is called the “exciter” and the second the “resonator”.

Watchmakers noticed that the pendulum’s beating often interfered with its surroundings and it was not unusual for a pendulum clock to stop by itself when it resonated with the weight hanging from the strings.

French watchmaker Antide Janvier, in the 1700s, thought for the first time to change this hitch into an improvement. He built two complete movements with two precision escapements and placed them close to each other, ensuring that the two pendulums were hanging from the same construction. Just as he imagined, the pendulums recovered the energy dissipated by one another and began to beat together, thus entering into resonance.

Resonance can be very useful in improving the chronometric accuracy of a watch. If two balances wheels are placed very close to each other, thanks to their alternating movement they set in motion a sort of third hidden balance wheel, the air. Being a fluid, it can be compressed and acts like a spring. Each balance compresses the same air which, like a spring, slows the faster balance by increasing friction and accelerates the slower one, decreasing friction. To tend, thanks to the resonance, the balance wheels come into sync and the precision of the clock considerably improves.

The implementation of this phenomenon to watchmaking has for centuries been limited to pendulum clocks: how to miniaturize and transfer it inside a case and take it from the wall to the wrist? This had been the task of F.P. Journe and his Chronomètre à Résonance, conceived and built, after 15 years of developing, to meet the demands of wristwatch and thereby provide chronometric performance driven to extremes. It was the first wristwatch to exploit the resonance, so much so that F.P. Journe patented the name Résonance before its launch.

F.P. JOURNE CHRONOMÈTRE À RÉSONANCE

In the Chronomètre à Résonance each of the two balances, very close together alternately serves as exciter and resonator. When the watch is fully wound and starts working, the balance wheels progressively balance their frequency and increase their inertia, that is the resistance to variations in motion. Thanks to the resonance phenomenon they begin to beat naturally in opposition. The two balances then support each other, giving more inertia to their movement.

This result is possible only if the difference of the frequency from one to the other does not exceed 5 seconds per day cumulated on six positions. Their setting is an extremely delicate task.

Whereas an external disturbance affects the running of a traditional mechanical watch, the same disturbance, for the Chronomètre à Résonance, produces an effect that accelerates one of the balances as much as it slows down the other. Little by little, the two balances come back towards each other to find their point of harmony, thus eliminating the disturbance, and beating in perfect synchronization.

The Chronomètre à Résonance has only one single barrel spring to provide power for the two movements. A differential placed on the first wheel, visible in the centre of the dial, transmits, independently, the energy of the barrel spring towards the two secondary gear trains. Each secondary gear train is equipped with a Remontoir d’Egalité of a frequency of 1 second. Working in such a way, the force received by the escapements remains linear and assures isochronism throughout 28 hours.

SUPERB TECHNIQUE AND POWERFUL AESTHETICS

Visually, the Chronomètre à Résonance is an example of balance and beauty. The platinum case is available in 40 or 42 mm, with a thickness of 11 mm, incredible when you think about the complications it houses.

It has been fully redesigned with a crown now placed at 2 o’clock easing the winding of the watch in position 0 and the time setting in position 2, clockwise for the left dial and anti-clockwise for the right dial. The pulling of the crown at 4 o’clock simultaneously resets both seconds.

The dial is in white gold and silver, with the double indication of the 24 hours, on the left, and the 12 hours, on the right, with blued hands like those of the seconds subdials. At 12 o’clock there is the power reserve indicator, which is approximately 42 hours.

F.P. Journe put the same care of dial finishing in the decoration of the movement, the caliber 1520, visible through the sapphire crystal caseback: Geneva waves on bridges, screw heads polished and beveled, with chamfered slots, pegs with polished rounded ends, steel components hand-finished. 

The Chronomètre à Résonance is available with a leather strap or an elegant 5-row polished platinum bracelet. Because aesthetics, in watchmaking, increase the value of technique. As F.P. Journe knows. (Price CHF 105.000)

By Davide Passoni