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Vacheron Constantin - One watch, two escapements and an exponential power reserve

Vacheron Constantin One watch, two escapements and an exponential power reserve

Along with three shades of blue, Vacheron Constantin showcases an innovative new escapement concept. One of the talking pieces of SIHH 2019.

Twin Beat: this is one of the words that will be remembered from the SIHH 2019 and, possibly, make it into the watch history books. A revolution? Hardly. And yet it’s the result of an exercise that is even more difficult: using existing techniques to invent something new, based on common sense and with a genuine added value for the customer. 

Its full name is the “Traditionnelle Twin Beat Perpetual Calendar” and it massively increases the power reserve from the usual couple of days to an impressive 65 days… without revolutionising the principles of mechanical watch movements, let alone the mainspring barrel. Its secret lies in offering the option of letting the movement beat at a frequency of 5 Hz or 1.2 Hz. The wearer can choose which one using a pusher at 8 o’clock. 

Hybrid mechanics

Une montre, deux échappements, une réserve de marche exponentielle

Traditionnelle Twin Beat Perpetual Calendar © Vacheron Constantin

To make such a feat possible, the watch has two barrels and two escapements. In other words, the Twin Beat has one escapement that beats at 5 Hz and another, totally independent one, that beats at 1.2 Hz (8,640 vibrations per hour). You can see both of them at 5 o’clock (1.2 Hz) and 7 o’clock (5 Hz) respectively. But the question is why not continually have the watch beating at 1.2 Hz to enjoy the 65-day power reserve permanently? 

The answer is a technical one: in order for the movement to beat at this low frequency, Vacheron Constantin had to develop a very special mainspring that is much longer but also much thinner than usual. Its cross-section is four times smaller than the mainspring coupled with the 5 Hz escapement and it is therefore much more fragile. It would, therefore, not stand up to regular daily wear. The Traditionnelle Twin Beat is designed to be worn at 5 Hz and “rest” at 1.2 Hz. 

An almost perpetual calendar

It is at rest that the watch offers 65 days of power reserve. Vacheron Constantin therefore judiciously added a perpetual calendar. The brand thus avoids the usual disadvantage of a perpetual calendar, which is that it has to be worn permanently, otherwise as soon as the watch stops the perpetual calendar has to be painstakingly reset. 

With 65 days of power reserve, this is no longer a problem. Even after leaving the watch for two months, it can be wound up and the time and date will be correct. The only pity is that the Twin Beat does not display the day, but this is no doubt due to the constraints of size and legibility – everything is packed into a case with a diameter of just 42mm, quite an achievement for a movement with nearly 500 components!

Une montre, deux échappements, une réserve de marche exponentielle

The Twin Beat and its two escapements © Vacheron Constantin

56 shades of blue 

Vacheron Constantin has chosen blue as the common denominator for the latest models in three collections: Patrimony, FiftySix and Overseas. There are two new models with blue dials in the Overseas collection. The first is surprising: an Overseas tourbillon. It’s nice to see a tourbillon in this legendary Vacheron Constantin case, but I do wonder about the relevance of a tourbillon’s function in a sporty watch. 

The ultra-thin Overseas perpetual calendar also has a new blue dial. It completes the current offer of grey and taupe dials. 

Une montre, deux échappements, une réserve de marche exponentielle

Overseas Tourbillon and Ultra-Thin Perpetual Calendar © Vacheron Constantin

Undoubtedly in fashion, blue is also applied to the Patrimony collection in the three-hand and annual calendar versions. The midnight blue goes perfectly with the gold case and it’s nice to see Vacheron Constantin going for different shades of blue for each model. The Overseas has its own blue, as do the Patrimony and the new FiftySix (SIHH 2018). Its petrol blue is today used on the three hand models with date and the complete calendar, yet strangely not on the day-date or tourbillon models. At least not yet.

Une montre, deux échappements, une réserve de marche exponentielle

Patrimony Retrograde Day-Date © Vacheron Constantin

The brand

An exploration of the history of Vacheron Constantin is a voyage of discovery, revealing the excellence of age-old watchmaking. Each timepiece is the result of the creative inspiration of the watchmaker or craftsman, dedicating their knowhow to the birth of outstanding watches. The Manufacture also works within a social and environmental code of ethics, and has had Responsible Jewellery Council certification since 2012.

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