Résonique: does the future of the mechanical watch lie here?

Par Timm Delfs

Usually we, the journalists writing about horology, are rather spoilt when it comes to horological sensations. We’re not easily excited when brands hurl superlatives the likes of “lightest, fastest, most complicated, rarest” at us. Usually it’s just somebody that has tried out a new alloy, reduced friction by using a new coating or has combined two well-known complications that have never been used that way. Even though in recent years a lot of research has been done in the field of the regulating organ of the mechanical watch, its fundamental principle has remained relatively unchanged: it is still composed of an oscillator in the shape of a balance-wheel equipped with a spiral hairspring, an invention by Christiaan Huygens that dates back to 1675, whose oscillations are kept alive by an anchor whose shape can vary. The greatest revolution so far, the quartz oscillator, has become a no-go in high horology.

However, from time to time there they are, the surprises, the exceptions. And, as usual, they don’t come from the big brands. A circumstance that should surprise, given the fact that the big names entertain entire armies of scientists and researchers to churn out innovations on a yearly basis. It seems that there is less bureaucracy to overcome in small companies, and self-responsibility happens to be the better motivator than pressure from above. There is no way to force people to be inventive.

resonique A novelty that really stirred the journalists’ curiosity about one year ago was the announcement of De Bethune’s mastermind Denis Flageollet that he and a young acoustic specialist by the name of Siddharta Berns were developing an escapement that had absolutely nothing in common with anything seen in a mechanical watch so far. There is hardly a single individual in watchmaking who has the same experience as Denis Flageollet with anything concerning the watch escapement.
During his time with De Bethune he has used the various Dream Watches of the brand to experiment with his ideas about ideal combinations of balance wheels and hairsprings. “I have come to the conclusion that we have reached a stage where the traditional anchor escapement can hardly be improved, and that it is time for something fundamentally different to take watchmaking a step further.” He himself had long thought about the possibility of regulating a watch by high frequency and resonance, but, not being a physicist, he sought help outside his domain. In Siddharta Berns he found a collaborator who had never before spent a thought about watch movements, a fact that Denis Flageollet considers the ideal condition to come up with something radically new.

And of such nature is the novel “Résonique” escapement. Under the microscope it looks amazingly simple and at the same time of a beautiful symmetry. To the end of a conventional gear train two further pinions are added, which accelerate a final wheel to 10 revolutions per second. The energy is derived from a conventional spring barrel. The final wheel is made from a magnetic metal and has a certain number of teeth, in our case 8. However, the teeth are not shaped according to a standard profile like the NIHS, as they do not have to mesh with anything. The teeth and the spaces between look more like a sine wave that has been brought into a circular shape. If this wheel turned slowly, and a frictionless pickup was to follow its contours, it would move up and down regularly, just like the membrane of a speaker reproducing a low sound.
Which already comes close to the duo’s idea – to regulate a watch through resonance in an audible range. But, the up and down of the sinusoid teeth was to be scanned without touching them.
In the system devised by Flageollet and Berns this is achieved through a tiny magnet mounted to the end of a very elastic resonator, in the simplest example a tuning fork. Its polarity must be so directed that the magnet is rejected by the tips of the teeth as they approach. It must be close enough to the toothed wheel so that the teeth can penetrate its magnetic field. As a tooth approaches, the magnet is pushed away, only to regain its original place as soon as the tooth has passed. With the speed of the wheel’s revolutions the frequency of the magnet’s vibrations increases. At a certain speed the magnet’s vibrations come close to the resonator’s inherent frequency. This is the frequency at which a resonator vibrates if excited by one single impulsion.

To stay with the example of the tuning fork: If you hit a fork that is tuned to the tone of A it will vibrate at a frequency of 440 Hertz. When the harmonic frequency of 926 Hz is reached in De Bethune’s assembly, the forces that interact between the wheel and the vibrating magnet become minimal. To make the gear train increase or decrease its speed necessitates additional energy. Thus a self-regulating balance is created when the resonator begins vibrating at its inherent frequency. This keeps the gear-train going at a constant speed for as long as the barrel furnishes enough energy. If the tiny magnet is manually removed from the escapement, the gear-train immediately accelerates to uncontrollable speeds.

Let’s assume our wheel has 8 teeth as mentioned initially, and its desired speed is 10 revolutions per second. In this case the resonator must have an inherent frequency of 80 Hertz to keep this speed constant. Flageollet underlined that the choice of the implemented frequency is more or less open. The only condition is the harmony between the components. The higher the frequency, the more reliable the system, underline its inventors. Berns thinks that frequencies in the audible range between 20 and 20’000 Hz are ideal for horological uses, which is why they have chosen to call their invention “Résonique”, from resonance and sonic.

At the first demonstration of the system in December 2011 Denis Flageollet underlined that what they were presenting was far from being applicable to an actual watch: “In order to be able to witness its becoming a reality we have chosen not to patent our invention, but to publish it like an open source computer program. We believe that the more people experiment with this system, the faster it will become a standard. We would just like to see that it stays in people’s minds who was at its origin.”

What advantages?
Siddharta Berns and Denis Flageollet have used silicon as a material for their resonator right from the beginning. The advantage of this material as being extremely insensitive to temperature changes and magnetism has already been proven in the shape of hairsprings made from it. As by its manufacturing process virtually any shape can be achieved, the design can easily be adapted to necessary changes.

If the system proves reliable, it promises to make possible mechanical watches whose precision comes close to a quartz watch. Since a movement’s frequency determines the smallest time-unit it can measure as a stop watch, the Résonique might be ideal for chronographs. An aesthetic plus will certainly lie in the second hand’s absolutely regular movement. Like in Seiko’s Spring Drive movement, the seconds hand will show an absolutely even time flow without any ticks or stops.