For a couple of seconds every hour, the dial looks like a mess, but then all is made clear. Meet the Harry Winston Opus XI. Click here to read WatchTime writer Martina Richter’s in-depth report on the watch for our July-August issue, along with a video of how its ultra-complicated movement works.
The circles, spins and flips of carnival rides were what inspired Denis Giguet in his design of the Opus XI, unveiled last year as part of Harry Winston’s Opus series featuring offbeat watches conceived by various independent watchmakers. Every hour, on the hour, in the span of 2 or 3 seconds, the hour display – a system comprised of a multitude of wheels, pinions, arbors, bearings and tiles – disintegrates into utter chaos and then returns to order for the remainder of the hour.
This chaos originates from a “completely normal” watch movement with manual winding, a 48-hour power reserve, and a frequency of 21,600 vph. The movement has a very large balance, which is visible in a cylindrical compartment sticking out from the side of the case. The movement was designed in the tradition of old pocketwatch movements, and can be seen through the transparent sapphire caseback.
The rest of the watch is anything but normal. The movement’s gear train ends in the minutes indication, which is itself quite unusual. It consists of two rotating disks in a small, cylindrical chamber similar to the one holding the balance. The larger outer disk runs smoothly and continuously to show the single digits, while the smaller, inner disk printed with numerals for the tens advances with a jumping action.
But even more unusual is the hour display, which is the watch’s centerpiece both literally and figuratively. It would not have been possible to make this display without recently developed design and manufacturing methods.
The display is powered by its own barrel. As the movement’s other barrel slowly unwinds, it supplies energy to this second barrel. Every hour, the display explodes into motion as the numeral for the “old” hour disintegrates and the new hour numeral takes shape in the center of the dial. Every numeral is composed of four tiny tiles, each bearing a segment of the numeral. There are 24 tiles in all. The tiles are disassembled and reassembled by means of epicycloidal gear trains.
An epicycloid describes the path taken by a point (like one of the tiles in the hour display, for example) on the circumference of a circle as that circle rolls around the circumference of a second, fixed circle. The rolling point traces curves whose shape depends on the radii of the two circles. The hour display of the Opus XI follows this principle and originates from several epicycloids.
The changing of the hour is triggered by the minutes display. At the end of every hour, a spring falls onto a cam to release the hour-display barrel which has, in the meantime, stored enough power to set the hour display in motion in a series of wild rotations. They last for 2 to 3 seconds, after which the barrel will have spent all its energy. The main movement barrel will immediately start feeding fresh power to the hour-display barrel so that it will be ready for the next hour change. During the intervening 60 minutes, the entire system in the main case body remains motionless and the current hour stays clearly visible in the center of the watch.
But what exactly happens when the spring falls onto the cam again and the second barrel is released to change the hour?
A toothed wheel that is almost as large as the entire main case of the Opus XI is in contact with the hour-display barrel. There are four smaller satellite wheels inside the large wheel. Once the wheel is set in motion by the barrel, it drives the four smaller inner wheels along its inner teeth. Geared platforms are mounted on their vertical arbors, along which three satellite wheels engage according to the same principle. Four times three equals 12 (hours). Conical wheels sit on the arbors of these last satellite wheels, which are needed to change direction from the vertical to the horizontal rotational axes of the arbors with the hour display tiles. Two tiles are attached to each arbor, and 12 times two equals 24 tiles. Each tile is printed twice, front and back, so 48 surfaces fit together, four at a time, to display the 12 hours.
To visualize how the tiles move, think about being in the car of a carnival ride, flipping over while the car rotates around a common midpoint along with two other cars, and circling around the main rotational axis of the ride as an independent satellite. Got it? After no more than three rounds it’s easy to lose your orientation. Fortunately, the individual tiles in the Opus XI always know exactly where to go next.
Finally, triangular gears are designed to manage the complicated turning maneuvers, along which elliptical wheels interact with the bevel gear satellites. The pairs of tiles attached to each satellite form the 12 hours. This means that after half a day the entire mechanism returns to its original position. After six hours the same tiles will be in the center of the dial and form an hour number. However, the tiles will be turned 180 degrees. In the same way, the entire system is shifted by 180 degrees. For example: the top left tile of the “11” (see photo) will become the lower right tile of the “5” after six hours – that is, its flip side, which after another six hours will again be the top left tile of the “11.” Within this period the satellite will have moved four times around the triangular gear and its arbor will have turned 30 times along with the tile. (To see a video of the Opus XI in motion, click below.)
The large wheel, which is driven by the barrel, continues to advance 90 degrees during an hour transition, in order to return to the same place after four hours. Its four satellite wheels will also be in the same position after four hours, but not its three additional satellites with their tiles. They will move 120 degrees during each transition, making one revolution around the triangular gear after a three-hour period. However, they do not return to the same configuration they were in three hours earlier. The tiles are now in a different location in relation to one another. In pairs, they alternately complete two or three half turns every time they change position. The triangular gear and the elliptical gears are designed so that they can vary these transmission ratios. This allows the tiles to pass by one another without colliding and to reappear in the center at the proper time. After three hours, the same satellite will again be in the center but show the reverse side of the tile. Depending on the tile, it will have turned seven or eight times, 15 times in six hours, or 60 times a day.
The incredible calculation and design work behind the hour-changing mechanism of the Opus XI was only made possible with computer programs that weren’t even designed a few years ago. Today these programs can calculate, analyze, draw and optimize the tooth shape of the triangular and elliptical wheels and how they mesh. The wheels themselves were created through the use of photolithography – a process where tiny components can be manufactured with a precision that cannot be achieved with conventional manufacturing methods. The conical pinions for the bevel gears, for example, are just 1.2 mm wide. Their shape, angles and teeth are perfectly accurate thanks to this new manufacturing technology. The shape and path of each tile was also calculated using computer technology in order to minimize the space required for the switching action. The case and sapphire crystal, which themselves are the result of complicated production processes, offer a broad view of the astonishing hourly movements. You may enjoy the exhilaration of a wild carnival ride – with the Opus XI it occurs once every hour.
As you might guess, Denis Giguet is no newcomer to avant-garde horology. Trained as an engineer, he served as head of production for Harry Winston. In 2007 he launched his own brand, Manufacture Contemporaine du Temps (MCT), and designed its flagship watch, the Sequential One – in which the hour numerals are each composed of five prism-like segments, arranged like slats in a Venetian blind, which flip over to form a new numeral at the appropriate time. Twenty technical specialists worked with Giguet to develop the Sequential One. They included Eric Giroud and Jean-François Mojon, who collaborated with Harry Winston on, respectively, Opus IX and X.
Manufacturer: Harry Winston SA, 8, Ch. du Tourbillon, CH 1228, Plan-les-Ouates, Switzerland
Reference number: 500/MMDGWL
Functions: Hours on 24 tiles, digital minutes on two rotating disks
Movement: Hand-wound Opus XI, produced since 2011, 21,600 vph (3 Hz), 566 components, 155 jewels, 48-hour power reserve
Case: White gold, three overlapping cylinders, sapphire crystals, water-resistant to 30 meters
Strap: Alligator leather
Dimensions: Diameter = 45 mm
Variation: With diamonds