Montblanc Collection Villeret 1858 – ExoTourbillon Chronographe

At the Salon International de la Haute Horlogerie (SIHH 2013) in Geneva, Montblanc unveieled two new and exclusive ExoTourbillon Chronographe models from the Montblanc Collection Villeret 1858.

The ExoTourbillon Chronographe adds another extraordinarily exclusive timepiece to the Montblanc Collection Villeret 1858. This regulator wristwatch combines a large minute-hand and elapsed-seconds hand at the centre of the dial, a small off-centre circle for the hours, a second time zone with day/night indication, a small hand for the continually running seconds and a chronograph with a counter for 30 elapsed minutes.

This Montblanc Collection Villeret 1858 Tourbillon first attracted admiring attention with its patented construction in 2010. Its balance is larger and oscillates on a different plane than the rotating cage. This exclusive timepiece now debuts in an attractive new edition which gives an entirely unprecedented look to its spectacular mechanisms. The 18 karat gold dial, which has a distinctively three-dimensional effect, is available with either black or silver-grey décor and with a finely grained texture that contrasts tastefully with shiny hands, applied subdials and polished steel components.

The ExoTourbillon Chronographe is the first watch in Montblanc’s Villeret 1858 Collection to unite two of the most avidly admired horological complications: a chronograph function and a tourbillon. Mastery of the difficulty of crafting these complications numbers among the distinguishing characteristics of the Montblanc Manufacture in Villeret, which has here combined the two complications in a highly unusual fashion: the chronograph upholds the lovely tradition with a column-wheel and horizontal coupling, and the four-minute tourbillon.

But what exactly does a tourbillon accomplish? Due to the subassembly’s architecture, the center of gravity of the balance and balance-spring in every mechanical watch is never absolutely collinear with the center of the balance’s axis of rotation. This off-centeredness causes a disadvantage when the watch is in a vertical position: the oscillations of the balance are disturbed by the influence of gravity on its eccentric center of gravity. The ingenious tourbillon mechanism was invented to solve this problem: the balance is borne inside a cage that continually rotates around its own axis.

The eccentric center of gravity accordingly orbits the tourbillon’s axis of rotation at this same rate. The accelerating effect caused by the Earth’s gravity on the center of gravity during the first 180° of the tourbillon’s rotation is compensated by an analogous de-accelerating effect during the second 180°. The long-term result is a movement that runs at a regular rate.

This clever mechanism underwent further optimization for the ExoTourbillon Chronographe: the balance has been separated from the cage to isolate it from the disturbing movements of the escapement. This separation made it possible to create the world’s first tourbillon in which the rotating cage is smaller than the balance, which oscillates outside the cage and on a higher plane. This architecture also inspired the watch’s name, which includes the Greek prefix exo, meaning outside. The balance in this unconventional configuration is borne between two jewels – it is neither cantilevered (“flying”) nor is it borne between two bridges – while the tourbillon turns at the foot of the axis in a two-point bearing.

The reason for this most elaborate construction is that the traditionally large and massive balance would have required a comparably large rotating cage if it had been positioned within a conventional tourbillon. A smaller tourbillon has less mass and consequently requires less energy for its rotations. The rotating cage is also freed from the weight of the balance, which further reduces the amount of energy it consumes. This architecture requires about 30% less energy than conventional constructions. The energy saved here can be used to power the chronograph’s functions.

Another essential advantage: Being separated from the rotating cage, the balance is not adversely affected by the inertia of the cage and consequently oscillates with greater precision. This innovation is entirely in accord with the statutory task of the Institut Minerva: namely, to cultivate the authentic Swiss watchmaking tradition and to combine it with ongoing innovation, thereby assuring a bright future for this noble and artful handicraft. It goes without saying that this invention has been registered for patent protection and that it will be used exclusively in the timepieces which comprise Montblanc’s Villeret 1858 Collection. The owner of an ExoTourbillon Chronographe can enjoy the spectacular vista of a large balance (with weight screws along its rim) that’s free to oscillate in all its beauty and turns around its own axis, without being cramped inside the narrow confines of the tourbillon’s cage. With commensurate self-confidence, it proudly presents itself in a large aperture cut into the dial at the “12 o’clock” position and above a plate that has been manually embellished with circular graining.

To honour these spectacular mechanisms, Montblanc is launching the unconventional monopusher chronograph with ExoTourbillon in a strictly limited new edition of eight timepieces in 18 karat white gold and eight wristwatches in 18 karat red gold.

Tourbillon Chronograph with New Regulator Dial 
Each model has the typical face of a regulator timepiece with a large minute-hand (and the chronograph’s elapsed-seconds hand) at the dial’s centre, complemented by an off-centre subdial for the hours with a pair of hour-hands for two different time zones: the hour in the local zone is shown by a golden hand with the same hue as the case; a blued hand indicates the hour in the other selected time zone. Various shapes arranged on different levels give the dial a strongly spatial effect that’s impossible to overlook. Time merely becomes the fourth dimension on this dial’s three dimensional stage. The performance begins with the clearly visible ExoTourbillon: its bridge is firmly screwed to a manually circular-grained plate and it offers an unobstructed view into the depths of the movement. The plate is coated with rhodium for the white gold watch; a layer of red gold gilds it in the red gold model.

The main dial is crafted from solid gold and adorned with a finely grained grainé décor onto which all displays – except the small continually running second-hand at “9 o’clock” – are added as appliqués in the same colour as the case. The subdial for the hours at “6 o’clock” has an outer and an inner numbered circle: these annuluses are separated from one another by a slightly inset zone with a fine sunburst pattern; both calibrated rings are circularly satin-finished and bear black Roman numerals. A slender raised border surrounds the subdial for the hours. A similar frame encloses the chronograph’s counter for 30 elapsed minutes at “3 o’clock”, where hands of different lengths and different colours serve two differently coloured scales for 0 to 15 and 15 to 30 minutes.

At “4:30” is the finely encircled 24-hour subdial with a blued hand – matching the blued hand for the second time zone This subdial’s semicircular scales are coloured either pale or dark to match the corresponding half of the day, and two greyish segments signify morning and evening twilight. The words “LEVER” (rise) and “COUCHER” (set) indicate the beginning and the end of the daytime hours at 6 a.m. and 6 p.m., respectively.

Monopusher Chronograph with Column-Wheel Control
The Calibre 16.60 is a chronograph movement with a large and centrally axial counter for the elapsed seconds, a counter for 30 elapsed minutes, a classical column-wheel and horizontal coupling. The chronograph lever is elaborately finished by hand, and the mise en fonction is likewise accomplished manually: the surfaces where the chronograph lever contacts the column-wheel and the heart disc are observed through a watchmaker’s loupe during the operation of the chronograph’s functions and are gradually and meticulously abraded to a tolerance in the hundredths-of-a-millimeter range. The steel parts and the chronograph bridge (in the “V” shape typical of Minerva’s products) are manually beveled and polished.

A finely grained stone is used to polish the lever; the bridges are manually adorned with Geneva stripes. The large and massive balance, with weight screws along its rim and a Phillips curve at one end of its balance-spring, oscillates at the classical frequency of 18,000 semi-oscillations per hour (2.5 hertz), which makes it possible to measure brief intervals to the nearest fifth of a second. The chronograph’s start, stop and return-to-zero functions are operated sequentially by depressing a button in the crown.

Second Time Zone and Day/Night Display
Frequent flyers will appreciate the fact that the ExoTourbillon Chronographe can display the time in two different time zones. The skeletonized hour-hand on the hours subdial indicates the local time, while the tip of the blued steel hour-hand points to the hour in the wearer’s home time zone. When the watch is worn in the home zone, these two hands are always positioned one atop the other; when the wearer travels to a different time zone, he or she can press the button at the “8” to advance the local-time hour-hand in single-hour increments until the hand indicates the correct local time. The current time at the wearer’s home is shown on the little 24- hour dial with day/night indicator and blued steel hand.

Collector’s Items in a Limited Edition
Also because they’re manufactured in strictly limited editions, the chronographs in Montblanc’s Villeret 1858 Collection are ardently sought rarities. This distinction is further enhanced by the extremely unusual combination of a chronograph and a tourbillon, and even further refined by the presence of a unique tourbillon construction. Only one unique piece of the ExoTourbillon Chronographe will be manufactured in platinum, along with limited editions of 8 pieces each in 18K white gold and in 18K red gold (5N).

Each of the impressive 47-mm-diameter cases is high-gloss polished and fitted with an arcing bezel that securely holds a highly domed sapphire crystal with vertically falling flanks (forme chevée). A pane of sapphire crystal is integrated into the back, which is screwed to the case and protected by a hinged cover which is opened by a patented mechanism concealed between the horns. Each watch is engraved with the words “Edition Limitée,” “Montblanc” and “Fait main à Villeret” (i.e. handmade in Villeret). The interior of the hinged cover is signed “Demetrio Cabiddu Maître Horloger,” thus identifying by name the technical director of the manufacture, who led the team that developed the Calibre 16.60.

This bears the gold-filled engraving “Minerva Villeret” and can be admired by peering through the pane of sapphire crystal in the back of the watch when the cover is opened. Naturally, the Montblanc logo hasn’t been forgotten: the familiar six-pointed star, which symbolizes the six tongues of the glacier that covers Europe’s tallest mountain peak, has represented the utmost in European handcraftsmanship for many decades. The same stellar emblems, executed in genuine motherof- pearl, grace the watches’ winding crowns.

These new collector’s items in Montblanc’s Villeret 1858 Collection are affixed to alligatorleather straps, each of which is equipped with a pronged buckle made of either 18K white gold, or 18K red gold, depending upon the material of which the model’s case is made. The new Montblanc Collection Villeret 1858 ExoTourbillon Chronographe will be available starting in January 2013.

Technical details
Model: Montblanc Collection Villeret 1858 – ExoTourbillon Chronographe
Ref 109150 und 109151

Movement
Calibre: MBM 16.60
Type of movement: Hand-wound with chronograph, small seconds, second time zone and four-minute tourbillon escapement
Chronograph: Monopusher mechanism with column-wheel and horizontal coupling
Dimensions: Diameter 38.4 mm; height 10,34 mm
No. of components: 341, including 51 components for the tourbillon cage
No. of bearing jewels: 32 (hemispherical, domed, olive-cut)
Power reserve: 50 hours
Balance: Screw balance, Ø 14.5 mm; 59 mgcm2
Frequency: 18’000 semi-oscillations per hour (2.5 hertz)
Tourbillon: One rotation every four minutes
Balance-spring: With Phillips terminal curve
Plate: Rhodium-plated nickel silver, circular graining on both sides
Bridges: Rhodium-plated nickel silver, côtes de Genève
Going-train: Gold-plated, faceted arms, hubs with diamond polished surfaces

Watch displays
The hours in the first and second time zone are shown at the “6,” the minutes are indicated from the center of the dial, continuous seconds on a subdial at the “9,” day/night indicator with 24-hour display between the “4” and the “5”
Chronograph: Centre seconds, 30 minute counter at 3 o`clock indicators

Case
Case 18 K white or red gold; domed sapphire crystal (forme chevée), transparent pane of sapphire crystal inset into screwed back beneath hinged cover
Dimensions: Diameter 47 mm; height 16,67 mm
Water tightness: To three bar (30 meters)
Horns: With patented mechanism to open the hinged cover on the underside
Crown: With integrated button to operate the chronograph and mother-of-pearl emblem
Pusher: In the case’s flank at 8 o`clock to adjust the second time zone

Dial
18 K gold with grained anthracite decoration (109150) / grained silver-plated decoration (109151), polished, satin-finished counters and Roman numerals
Hands 18 K gold, chronograph’s elapsed-seconds handmade of PfinodalTM

Wristband: Hand-sewn alligator-leather pronged buckle made of 18 K red gold or 18 K white gold
Limited edition: 18 K white gold and 18 K red gold, limited to 8 pieces each

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