Breguet Transcendental Double Tourbillon

Breguet's Classique Double Tourbillon 5347, released in 2006, was a masterpiece that overturned conventional wisdom about tourbillons. 14 years later, Breguet released the Quai de l'Horloge, a model with the dial removed. The movement, equipped with two one-minute tourbillons, rotates once every 12 hours. Its design and outstanding finish make it a milestone for the modern tourbillon.

The Secret of Breguet Double Tourbillon
The mystery will be solved after watching the film...

　Breguet's "Classique Double Tourbillon" rotates a plate carrying two one-minute tourbillons once every 12 hours. Released in 2006, this model represented the pinnacle of modern tourbillon technology, as it was able to rotate such a heavy structure. Without a skilled designer, precisely machined components, and an outstanding watchmaker, smoothly rotating a heavy rotating body would have been impossible.

　However, if the double tourbillon is covered by the dial, the mechanism cannot be seen. So Breguet decided to remove the dial. This resulted in the "Classique Double Tourbillon 5345 "Quai de l'Horloge", released in 2020. In this model, not only is the movement visible, but some parts are skeletonized, and the plate that rotates once every 12 hours has also been changed to 18K gold.

The double tourbillon movement, which rotates once every 12 hours, is by no means thin. Breguet made the watch appear thinner by making the sapphire crystal crystal more three-dimensional. As the photo shows, the two tourbillons and the bridge that supports them, which also serves as the hour hand, protrude from the side of the case. As befits a flagship model, the case finish is impeccable.

　The design has also been modified. The bezel has been narrowed and the box sapphire crystal has been made more three-dimensional, emphasizing the classic style. The back of the movement also features an engraving of the Quai de l'Horloge in Paris, where the first Abraham-Louis Breguet established his workshop.

　The two tourbillons rotate once every 12 hours to function as the hour hand. The reason this mechanism, which was considered difficult to actually operate, works is due to its excellent design. When the crown is turned, the mainspring housed in the two barrels is wound, which then rotates the two tourbillons via their respective gear trains. Torque is branched off via a system separate from the two gear trains and transmitted to a differential gear at the center of the movement. The differential gear is fixed to the main plate, and the plate carrying the two tourbillons rotates once every 12 hours around the differential gear.

　Initially, Breguet considered a design in which the torque from the two barrels would be transmitted to a differential gear and then split off into two tourbillons. However, this would have caused the hands to move when the movement was wound, and the mechanism would have become more complicated, so they changed to the current design. Furthermore, to ensure safety, Breguet adopted a "mature" mechanism for the basic mechanism. The two tourbillon gear trains were adapted from the Classique Tourbillon 3357. This gear train, whose basic design dates back to 1990, was already fully mature as of 2006.

　However, it would be impossible for the two tourbillons to rotate once every 12 hours using only this mechanism. Breguet used ball bearings on the axis of the plate supporting the two tourbillons. Furthermore, by further improving the precision of the gear machining, the plate's rotation became smoother. However, even if the rotating plate functions as the hour hand, it would not be a watch without a minute hand. Breguet extracted power from the plate, which rotates once every 12 hours, and attached the minute hand to the center by engaging multiple speed-increasing gears. While this may sound simple, the more gears there are, the greater the play, and the more likely there is to be a discrepancy between the rotating plate (which functions as the hour hand) and the minute hand. Even if the correct pointer is achieved by rotating clockwise, play will occur in the gears when rotating counterclockwise, and the pointer will still be misaligned. By incorporating spring properties into the speed-increasing gear, which transmits torque from the rotating body, Breguet completely eliminated the play in the gears when rotating clockwise or counterclockwise. As a result, there is absolutely no discrepancy between the heavy rotating plate and the minute hand. Of course, setting the hands is extremely smooth, both forward and backward.

　Confident in this mechanism, Breguet undertook an ambitious experiment with the new Quai de l'Horloge: an 18K gold baseplate. "In homage to the Marie Antoinette watch of the past, we have used the same gold for the baseplate," Breguet explains, but the watch weighs an astounding 44g. While the usual solution would be to increase the torque, Breguet chose not to do so because the resistance was extremely low to begin with. The 18K gold was also changed to a special alloy. This new gold alloy, with a Vickers hardness of HV330, made it possible to use gold, which is normally soft, in functional components.

The double tourbillon, which is equipped with two barrels, uses a mainspring that slips into one barrel to prevent overwinding of the mainspring housed in the barrel. The crown itself also has a built-in clutch that slips when wound with more than a certain amount of force, preventing overwinding of the mainspring. Although it is an extremely complex tourbillon, the true essence of Breguet lies in its ability to be worn on a daily basis.

　In addition, the movement of this model is hand-finished. As one famous designer once said, ideally, a watch should not have any finishing work done, as this would change the weight of the parts and cause uneven rotation. Leaving aside ordinary watches, this effect is even greater in the case of a Quai de l'Horloge, which rotates heavy parts. However, by completely controlling the uneven weight, Breguet has overcome the problems that arise from decoration and finishing. What makes this model stand out is that, despite the traditional decorations such as guilloching, the plate rotates perfectly, which is surprising.

　Combining modern technology with exceptional craftsmanship, this timepiece is not just the pinnacle of tourbillon excellence, but also the pinnacle of modern haute horlogerie.