From tower clocks to wristwatches, the history of clock- and watch-making over the past four centuries chronicles the ever-increasing miniaturisation of mechanisms. Up until now, the power needed to drive a wristwatch mechanism has been a limiting factor in terms of design and innovation. Greubel Forsey’s fundamental work on Mechanical Nano, based on the mastery of energy and available space, is once again confirmed and now applied in a watch mechanism.
In the process of developing the 180-day power reserve movement, the decision was taken to apply Mechanical Nano to the foudroyant jumping seconds mechanism. This watchmaking complication consists of a hand that makes one rotation every second to indicate the fractions of a second.

For over ten years, Greubel Forsey’s EWT —Experimental Watch Technology— Laboratory has been working to push the boundaries of mechanical watchmaking and has had particular success in the domain of the Mechanical Nano project. Thanks to this totally new concept and following the recent application of patent No. EP 3220207 A1, Greubel Forsey is unveiling the first Nano Foudroyante EWT.

Mechanical Nano has led Robert Greubel and Stephen Forsey, as well as the engineers and designers at Greubel Forsey, to completely rethink the mechanism of the traditional foudroyant jumping seconds. This new construction consists, first of all, of a mobile (a) with a very low moment of inertia, which takes its information directly from the escape wheel (b). This principle means that a full gear train is no longer needed to ensure the sub-division of seconds (c), since the information is obtained from the wheel, which distributes and gives the rhythm to the energy of the movement. Energy consumption can now be expressed in nanojoules (nJ).

The first Mechanical Nano watchmaking application focuses on the reduction of inertia and on the energy savings it made possible. The display of the Nano Foudroyante EWT is by a miniature hand. This is made clearer to read by an optical system with 23x magnification.

Practical EWT Laboratory tests confirm the theory and calculations, corroborating the studies on the savings of energy and space. On the basis of this first demonstrator there are a number of different innovative possibilities that will enable further optimization of energy. Compared to a traditional foudroyant jumping seconds mechanism, the Greubel Forsey Nano Foudroyante EWT consumes 1,800 times less energy and occupies 96% less space. All of this research has made it possible to create a truly original and innovative foudroyant jumping seconds mechanism that makes best use of energy and available space in the movement of a mechanical timepiece.

Having initiated the project over a decade ago, research and development on a movement with a 180-day power reserve is still going strong. Following validation of the reduction of inertia with this demonstrator, Greubel Forsey’s EWT Laboratory is currently working on validating a Nano Foudroyante based on the same fundamental principles, where the foudroyant jumping seconds is displayed on a standard size subdial: the Nano Foudroyante à Affichage. The practical results obtained from this research will be featured in an upcoming publication.
Sharing is a value that is dear to both Robert Greubel and Stephen Forsey. To that end, progress on Mechanical Nano research will be made public at regular intervals. So far this is getting quite interesting.

You can read about the first release of Mechanical Nano earlier this year here.

For more info on Greubel Forsey click here.