Quantum Leap: A Look Inside The URWERK UR-300 ‘Time Quantum’

Urwerk officially launched the UR-300 Time Quantum at WatchTime New York, during New York Watch Week, but the complication – which is a kind of hybrid of a jumping hours and wandering hours display – was soft-launched under embargo during Geneva Watch Days, when visitors to Urwerk’s headquarters in Geneva’s Old Town were shown the movement. The completed watch was available to experience last week, and it’s both directly related to Urwerk’s previous work, and also a new take on displaying time. The watch, says Urwerk, was inspired by the world of quantum mechanics – I think this is actually the first time that any watch company, independent or not, has been directly inspired by quantum mechanics – and the display is both startling in action and rather mysterious, as the display switches so quickly it is very difficult to understand the mechanism at first.

At first there’s a superficial resemblance to some of the preceding Urwerk satellite systems, which over the years have been reinvented over and over again since the first wandering hour disk display debuted in the UR-101. We have seen satellite cubes with a telescoping minute hand, a system with a retrograde frame, roller based designs (one of my  personal favorites is the UR-111C) and on and on. The UR-300 Time Quantum, however, is a genuinely new variation on the theme.

The display consists of two carriers, offset 90º from each other, forming a “T-Frame.” Each carrier has two three-sided modules, or “time prisms,” each carrying a number (a total, therefore, of 12; one face for each hour.) Urwerk calls the carrier whose long axis is on the center axis of the movement, the “stem” and the one which is at right angles to it, the “crown.”  The module showing the current hour sweeps across the minutes track, which is a 108º arc, which is so far more or less business as usual, but when the hour is up, several things happen at once.

The entire T-Frame jumps forwards by 72 degrees, bringing the next hour prism in alignment with the zero seconds mark. At the same time, both carriers rotate 120 degrees on their long axes, so that the correct hour is displayed. Finally, the two crossbars switch places, with the former crossbar becoming the new stem, and the former stem, becoming the new crossbar.

There is an arm which carries the entire display, and which rotates 180º per hour (via a reduction gear that is, presumably, driven by the minute wheel, which rotates once per hour). The number of degrees which a given hour prism travels, however, is 108º, thanks to the 72º jump which takes place at the end of the hour (180º – 72º = 108º)

Fundamentally, this is not all that different from a retrograde seconds display and despite the apparent complexity of the mechanism, it appears to be very elegantly designed. Just as in a retrograde seconds display, the jump of the time display is thanks to a rack C, which rides on the edge of a cam E (in red). As the rack’s cam follower D is pushed outward by the cam, the spring F is tensioned. When the cam follower drops off the highest point of the cam (also at F, though it’s a little hard to see) the rack snaps counterclockwise and the module B snaps clockwise 72 degrees. Via a system of crown wheel gears, this horizontal rotation is translated to axial rotation of the crossbar and stem, bringing the hour prisms into the correct alignment.

The biggest challenge with making a display like this is the inertia which has to be overcome at the top of each hour, when the entire display has to jump forward 72º. The materials used for the display module are something of a who’s who of traditional and more exotically modern materials, including beryllium copper, brass, anodized aluminum, ARCAP AP1D (a non-magnetic nickel silver alloy) titanium, and LIGA fabricated nickel.

The watch also uses a variation of Urwerk’s Dual Flow Turbines, in which air resistance is harnessed to absorb shocks, control delivery of torque to the automatic winding system, and increase the longevity of the automatic winding components (which are the hardest workin’ components in watchmaking except maybe for the mainspring barrel).

Considering the rather spectacular piece of horological showmanship you get once per hour, the engineering which makes it possible seems to be excellent (if an amateur may presume to compliment Martin Frei and Felix Baumgartner) and the relative economy of means with which they have achieved this effect is admirable. You do gasp a little bit the first time you see the display do its thing; it’s fast, and although you expect a near instantaneous jump from a simple retrograde seconds, getting all these extra components and subassemblies to play nice together, took some doing.

The Urwerk UR-300 Time Quantum drew inspiration from a couple of different aspects of quantum mechanics, at least as I understand it. The name “quantum” comes from the fact that values in quantum mechanics are quantized; the energy state of an electron, for instance, can only assume certain discrete values, and as energy states change, the electron jumps instantaneously from one level to another. I thought of the whole (open) problem of wave function collapse, too – the state of a quantum system is described by the Schrödinger wave equation, which gives the probability of finding a subatomic particle at a particular location at a particular time. That we do not experience the wave function as an ensemble, but rather, only discrete specific outcomes, is one of the most intractable open problems in quantum mechanics (and has been for decades).

Regardless of the degree of exactness with which you might think the UR-300 has captured some aspects of quantum mechanics, it is I think a highly evocative watch and although it has much of the almost Brutalist, science-fiction flavor of much of Urwerk’s watchmaking, it also (at least for me) induces a sense of wonder as well. You don’t have to be interested in quantum mechanics to find the watch interesting, of course – there is plenty 0f cutting edge horological innovation to go around – but as a kinetic sculpture which expresses some ideas from quantum mechanics in a classical mechanical idiom, it has a lot to offer as well.

The URWERK UR-300 Time Quantum: case, 45.2mm x 18.25mm x 58.8mm, in Grade 5 titanium, or Grade 5 titanium coated with PE-CVD black treatment; water resistance 20 meters. Movement, caliber Ur-30.01V, with hours, minutes and seconds, and prograde wandering indicator; seconds shown by 3 hands rotating thorugh 120º. 25 pieces in each case treatment worldwide; price, CHF 168,000.