Credits: Article and images by Jeremiah Chan @ Revolution Watch Magazine. See the original article here - https://revolutionwatch.com/introducing-the-h-moser-cie-pioneer-cylindrical-tourbillon-skeleton/
The Straumann Double Hairspring, while a work of genius and used only sparingly due to its exorbitant cost to produce, is not what we see used here, in the first skeletonized watch Moser has made in the past seven years. Instead, the good folks at Precision Engineering AG, Moser’s sister company, have decided to revive a hairspring design they first unveiled in 2018: the cylindrical hairspring — although, it must be said its invention dates all the way back to the 18th century. English watchmaker John Arnold was its inventor and they found much use in the marine chronometers at the time, which helped establish the might of the British Navy.
How did the cylindrical hairspring enable the marine chronometers to be the amazing timekeepers that they are? Due to its shape, it vibrates in a concentric manner — meaning, the oscillations move in a direction perpendicular to the balance wheel swings instead of laterally like in a traditional flat hairspring. This concentrates the center of gravity of the oscillations toward the balance staff. Add to that Moser’s use of two Breguet overcoils at both ends of the hairspring, which only increases the concentric motion and gravity centering effect. With reduced lateral forces — or less sideways pull, so to speak — there is less friction experienced by the balance pivots. Couple this hairspring with its cylinder shape and Breguet overcoils, with a tourbillon cage that constantly rotates the balance and escapement, and you have a gravity-defying, accuracy-improving triple threat. Unfortunately, the complexity and difficulty of curving a cylindrical hairspring by hand means it takes 10 times as long to produce than a traditional hairspring; and, just like the Straumann, it will only make an appearance in truly exceptional releases.
Credits: Article and images by Jeremiah Chan @ Revolution Watch Magazine. See the original article here - https://revolutionwatch.com/introducing-the-h-moser-cie-pioneer-cylindrical-tourbillon-skeleton/