The new Montblanc ExoTourbillon Rattrapante presented yesterday at "Watches and Wonders" in Hong Kong

The new Montblanc ExoTourbillon Rattrapante presented yesterday at “Watches and Wonders” in Hong Kong

ExoTourbillon Rattrapante from the Montblanc Collection Villeret 1858

ExoTourbillon Rattrapante from the Montblanc Collection Villeret 1858

The split-second chronograph movement of the Montblanc ExoTourbillon Rattrapante

The split-second chronograph movement of the Montblanc ExoTourbillon Rattrapante

It’s really rare to see press releases that are packed with so much detailed information as this one. Anyone passionate about horology will find it delightful to have all the functionalities of this grande complication explained.

Press release

The new ExoTourbillon Rattrapante from the Montblanc Collection Villeret 1858 was presented to the public and the international press at the “Watches & Wonders” exhibition in Hong Kong on 25 September 2013.

With the spectacular ExoTourbillon Rattrapante, the Montblanc Collection Villeret 1858 presents a new masterpiece that can be described without exaggeration as a world premiere in the world of watches. This model offers an unprecedented combination of numerous horological complications: a large balance positioned outside the tourbillon’s rotating cage, a chronograph with split-second function, and a three-dimensional regulator dial in gold and grand feu enamel.

Grandes complications are one of the playing fields on which Swiss watchmakers celebrate their globally unique status. This is a terrain that can best be characterized as the “home stadium” for the Montblanc Manufacture in Villeret. The latest example of Montblanc’s expertise, which will debut at “Watches & Wonders” in Hong Kong, adds new challenges to familiar and avidly coveted complications.

Unlike a conventional tourbillon, Montblanc’s ExoTourbillon frees the large screw balance from the burden of the rotating cage. Rather than offering a mere chronograph, the new model encases a split-second chronograph with two column-wheels and a classical double clamp. And instead of an ordinary face, the watch’s dial is a fascinating three-dimensional arena of massive gold and grand feu enamel.

This masterful combination of the traditional watchmaker’s art and trailblazing innovations
comes with an 18 karat white gold case and a regulator dial. The exceptional novelty shows the time in a second zone, includes a day/night indicator and is manufactured in a limited edition of eighteen timepieces.

A complicated history

Rattrapante or split-second chronographs justifiably rank among the so-called grandes complications. It’s quite likely that the first split-second chronograph was built by the Swiss watchmaker Louis-Frédéric Perrelet, the grandson of the watchmaker Abraham-Louis Perrelet of Neuchâtel, who invented automatic winding by means of an oscillating weight in the 1770s. Louis-Frédéric Perrelet presented his “time counter with double counter” in 1827.

This invention included two second-hands positioned one above the other: one of them ran continually whenever the chronograph function was active; the other could be momentarily halted at the push of a button to measure an intervening interval. When this button was pressed again, the temporarily halted hand would catch up and return to synchrony with its companion. The French verb rattraper means “to catch up”, so Perrelet named his ingenious mechanism “rattrapante”.

Other sources credit the invention of the split-second chronograph to the Austrian watchmaker Joseph Thaddäus Winnerl, who settled in Paris in 1829. In Perrelet’s device, after the rattrapante-hand has been halted and an intervening interval has been timed, a spiral spring draws the hand back to its continually running counterpart. Winnerl, by contrast, devised a construction with a heart-disc and a heart-lever that exerts pressure to return the rattrapante-hand to the desired position. The system with a heart-disc, which is still in use today, inspired the two Swiss watchmakers Henri-Féréol Piguet and Adolphe Nicole to create a zero-return mechanism for chronographs around 1862.

Great efforts for interim results

Ordinary chronographs define the upper limit of so-called “everyday” or “petites complications”, but split-second chronographs are grandes complications in the truest sense of the phrase. Extraordinary mechanical complexity and almost 70% more components than for a conventional chronograph mechanism are needed to enable them to perform their useful function, i.e. momentarily halting the split-second hand to indicate an intervening interval without interrupting the ongoing measurement of an elapsing interval by the chronograph’s elapsed-second hand per se.

The watchmakers’ efforts are all the more laborious for delicate steel parts, which impose the utmost demands in manufacturing, finishing and assembly. Fabrication at Montblanc in Villeret occurs almost entirely by traditional manual craftsmanship, so significantly more time and labour are required. All this prior to the “mise en fonction”, when hours or days of meticulous work are lavished on all functional parts of the chronograph and split-second mechanism, which are finely adjusted and, if necessary, delicately abraded. The “mise en fonction” is performed on the fully assembled mechanism: the desired function is triggered and the interplay is scrutinized under a loupe; after noting even the slightest irregularities, the watchmaker disassembles the mechanism and finely tunes it, e.g. filing away a mere 1/100th of a millimetre or making a miniscule shift in the position of a lever; the movement is then reassembled and re-examined under magnification. This process may need to be repeated five, six or more times until everything interacts as expected from a movement made by Montblanc in Villeret.

The result is a split-second chronograph movement that elicits sighs of rapture from every watch aficionado who beholds it. When a connoisseurs trigger the chronograph’s functions, many of them will peer through the pane of sapphire crystal in the back of the case and admire the column-wheel (which controls the basic chronographic functions), the split-second column-wheel (which opens and closes the brake-clamps of the split-second wheel), and the manually bevelled steel levers (which, when the corresponding buttons are pressed, transfer their commands to the column-wheels and thence to the gear-coupling, the zero-return hearts and the brake-clamps).

Also visible are the slender, elegantly curved, steel springs that press the rattrapante-clamps against the split-second wheel when the rattrapante button at “2 o’clock” is pressed to allow the user to read the duration of an intervening interval. When this button is pressed again, the clamps spread apart and the zero-return heart automatically returns the split-second wheel to synchrony with the chronograph-wheel so that the split-second hand re-joins the chronograph’s elapsed-seconds hand and resumes
running in unison with it.

Villeret: The adopted homeland of chronographs

Villeret, a small village in the Jura Region in the Canton of Bern, lies almost exactly at the midpoint of an imagined line connecting the watchmaking metropolises of Biel/Bienne and La Chaux-de-Fonds. The cornerstone for the Minerva watch factory, which evolved into today’s Montblanc Manufacture in Villeret, was laid here in 1858. From its earliest days, incredible dynamism proved that this business was striving for a place among the leaders in its industry.

Most of its competitors were mere “établisseurs”, i.e. they purchased components from external sources and assembled these parts to produce complete watch movements. But the ambitious people at the manufacture in Villeret had already begun developing their own calibres and laboriously fabricating them by hand. These movements embodied the highest degree of quality and were duly awarded prizes at international industrial expositions.

Production expanded to include chronograph movements starting in 1887: these calibres were initially in larger formats for use in pocket-watches, but were soon afterwards also made in smaller sizes for wristwatches. Ongoing specialization in chronographs led in the mid 1930s to the construction of Calibre 19-14, which included a balance that oscillated back and forth 100 times per second and could accordingly measure elapsed intervals to the nearest 100th of a second. Also built were split-second stopwatches, i.e. so-called rattrapante chronographs, which could measure intervening spans of time without interrupting the measurement of an ongoing interval. Successfully used at the Winter Olympics in 1936, these watches formatively contributed to Minerva’s worldwide reputation.

The Patented Montblanc ExoTourbillon

Tourbillon escapements are another specialty of the master watchmakers at the Montblanc Manufacture in Villeret. Especially when they’re installed in watches with large and massy balances, these devices pose the utmost demands on their makers’ skills and dexterity.

The tourbillon was invented more than two centuries ago to counteract the disturbing influence which the Earth’s gravitation exerts on the steady oscillations of a watch’s balance.

A tourbillon rotates the entire escapement around the balance’s staff at an unvarying speed, thus compensating for rate errors caused by slight eccentricities in the centre of gravity of the balance and hairspring when the watch is in a vertical position.

With the Tourbillon Bi-Cylindrique, the Montblanc Collection Villeret 1858 again debuted an exclusive new timepiece that differs in several respects from everything previously seen in haute horlogerie.

This is the first wristwatch with a tourbillon escapement that ticks with two cylindrical hairsprings that have identical torques but unequal diameters and that are concentrically positioned one inside the other. This unprecedented device makes it a pleasure to reveal the mechanisms and the mode of functioning of the legendary heures mystérieuses display.

Constant innovation, i.e. the unceasing quest for the new and the unprecedented, is another indispensable element in Swiss watchmaking tradition as practiced by Montblanc in Villeret.

This striving again expresses itself in the patented ExoTourbillon, where Montblanc has further optimized the ingenious tourbillon mechanism and made it even more attractive. The Ancient Greek prefix “exo” means “outside”. This exteriority is meant in two senses for the ExoTourbillon from the Montblanc Collection Villeret 1858. First, the rotating cage and the escapement are positioned outside the movement’s plate per se and are located, so to speak, alongside the movement. Second, the balance is installed outside the rotating cage and oscillates on a different plane. Timepieces in the Montblanc Collection Villeret 1858 reap significant benefits from this novel repositioning. The uncommonly large and massy balance would have required a larger rotating cage if it had been mounted inside a conventional tourbillon construction. But the ExoTourbillon cage has a smaller diameter than the balance and rotates beneath the gleaming golden screw balance.

The balance is borne between two bridges, the upper of which has a looped shape that recalls a horizontal figure-of-eight as the symbol of infinity. The tourbillon rotates in a two point bearing at the foot of the axis.

Another exclusive feature of the ExoTourbillon is the speed of its rotations, each of which requires four minutes. Conventional tourbillons typically complete one rotation per minute.

Slowing the speed of the rotations enhances the observer’s pleasure and requires less energy from the barrel, but produces the same compensating effect as a speedier tourbillon.

The hairspring with an upward Phillips curvature at its outer end oscillates at the traditional pace of 18,000 semi-oscillations per hour (2.5 hertz) and thus enables this chronograph to measure elapsed intervals to the nearest fifth of a second.

Reducing the tourbillon’s rotational speed by 75% yields considerable energy savings. The rotating cage is smaller and has less mass, so its rotary motion requires less energy as well.

Furthermore, the balance is freed from the weight of the rotating cage, which yields a further reduction in its energy requirements. Montblanc’s innovative device requires more than 30% less energy than conventional constructions, and this is advantageous for the functioning of the split-second chronograph.

Another essential benefit ensues from separating the balance and the rotating cage: the accuracy of the balance’s amplitude is improved because the balance is not influenced by the inertia of the cage.

Due to the ExoTourbillon’s innovative configuration and despite the greater mechanical complexity of the split-second chronograph, the rattrapante can function more precisely. It can at the same time rely on the same barrel and the same power reserve as the basic chronograph movement. These advantages would not have been possible in a chronograph that does not rely on the patented ExoTourbillon construction.

Thanks to a patented energy-saving mechanism in the ExoTourbillon Rattrapante, the precision of measurements of the overall elapsed time and the intervening intervals by the ExoTourbillon with chronograph function is wed with a cleverly designed split-second function. With the rattrapante mechanism as the most complicated form of chronograph, the Montblanc Manufacture in Villeret demonstrates its competence in the most challenging “freestyle” aspect of the chronographic discipline.

The grand theatre of haute horlogerie

The new ExoTourbillon Rattrapante doesn’t only spark enthusiasm because of its globally unique combination of complications, but also thanks to its fascinating face, which serves as a grand stage for unconventional mechanisms. Rather than merely peering at a flat dial, the viewer’s gaze enters into an elaborate and meaningful three-dimensional structure that gives a sculptural quality to this timepiece. The excitement already begins where there’s no dial at all, i.e. at the circular aperture through which one can admire the ExoTourbillon.

The ExoTourbillon is positioned outside the movement plate per se, so the partially openwork dial and the transparent pane of sapphire crystal in the back of the case offer deep and rewarding insights. The regulator dial is a multipart construction of massive gold. Its primary surface is plated with rhodium and adorned with a grainé décor, the area around the tourbillon is recessed slightly. It is surrounded by a flange (réhaut) that’s calibrated with a readily legible fifth-of-a-second scale for the chronograph and that simultaneously shows the sequential minutes. All other scales are crafted as grand feu enamel appliques. The applied scale for the continually running second-hand is at the “9”, the chronograph’s counter for thirty elapsed minutes is at the “3”, and the bipartite enamel applique at the “6” hosts the hours display in two time zones and the 24-hour display for the home time. Grand feu enamel ranks among the oldest and most sophisticated techniques for decorating precious timepieces. It’s also the longest-lasting embellishment, which preserves its colour and gleam for centuries.

Limited Edition in 18 Karat White Gold

Laborious handcraftsmanship, performed in accord with the authentic Swiss watchmaking tradition and invested in each ExoTourbillon Rattrapante from the Montblanc Collection Villeret 1858, naturally limits the number of watches in the series of this grandes complications timepiece. The model is therefore available only in a strictly limited edition of eighteen watches, each with an 18 karat white gold case.

The circular gold case measures 47 mm in diameter, is polished to a high-gloss finish, and bears a highly domed sapphire crystal with vertically descending flanks (forme chevée) that optimally complements the distinctive shape of the case. The screwed back includes a sapphire crystal viewing window through which a connoisseur can admire the full beauty of the elaborate mechanisms of this chronograph with additional split-second function. The chronograph’s column-wheel is visible at “6 o’clock”; the split-second column-wheel can be seen near the split-second button; and between the two, an aficionado will find the artistically shaped coupling-, braking- and heartlevers, as well as the split-second clamps with their springs. The edges of these components are bevelled, their surfaces are brushed, and their flanks bear fine, elongated embellishments. The perfection of these elaborate decorations is assured only when they’re crafted by hand. Their bright gleam contrasts beautifully with Geneva waves on the bridges, glossy red jewels, and gold-plated wheels.

This new collector’s item from the Montblanc Collection Villeret 1858 is affixed to a black alligator-leather wristband equipped with a pronged buckle made of 18 karat white gold.