The search is (still) on for new escapements

One is the Genequand Escapement, the other the IsoSpring. Both result from ongoing research at Centre Suisse d’Electronique et de Microtechnique in Neuchâtel (CSEM), and the recently launched Instant-Lab, part of Ecole Polytechnique Fédérale de Lausanne (EPFL), sponsored by Patek Philippe. Unveiled last September during the Société Suisse de Chronométrie Study Day, these two inventions have ignited interest within the industry. The Genequand Escapement and the IsoSpring replace the balance spring with vibrating blades to produce oscillations. The former incorporates a conventional regulator system with escape wheel, pallet and oscillator. The latter takes a less travelled road.

Phenomenal power reserve

Pierre-Marcel Genequand, a now retired engineer at CSEM, invented the Genequand Escapement in 2000. A decade later, Vaucher Manufacture came onboard and the project took shape. Engineers are now working to make the system reliable, after the all-important first stage of miniaturisation. Their objective is to launch production within a three- to five-year timescale. Vaucher Manufacture will enjoy exclusive rights to use the escapement through sister brand Parmigiani Fleurier.

The Genequand Escapement significantly increases power reserve thanks to its low energy consumption. Test phases showed that a standard calibre equipped with this new escapement ran for a month and a half instead of eight days. Its principal characteristic is to replace the balance spring and pivot by two micro-blades which intersect to produce a regular alternating movement. The virtual pivot corresponds to the point where the two blades intersect. The Wittrick balance, named after William Henry Wittrick, a specialist in vibration systems, is in permanent contact with the pallet. Inspired by Harrison’s grasshopper escapement, the movement of the pallet is controlled by flexible blades. A corrector above the balance slows its movement if necessary to maintain isochronism. The parts of this innovative escapement are made from silicon. The current prototype operates at a frequency of 2.5 Hz, although Takahiro Hamaguchi, who is head of movement research at Vaucher, has announced that the second prototype is already at 18 Hz or 129,600 vibrations per hour.

Is one direction the only direction?

Developed by Instant-Lab at the Swiss federal institute of technology (EPFL) in Lausanne under Professor Simon Henein, the IsoSpring system replaces the conventional escapement with a unidirectional regulator, in the form of a two-dimensional structure which vibrates in a regular and controlled manner. The IsoSpring, which is still at the experimental stage, therefore has two degrees of freedom. It comprises two independent blade-springs, positioned at an angle of 90°. Using a structure first theorised by Isaac Newton in 1687, the two blades produce an elliptical, unidirectional and highly regular movement. Even if speed varies, the time period remains constant, ensuring the regularity required to measure time. The team is working to reduce the size of the imposing prototype, which is currently driven by a crank handle turning in one direction.

The Genequand Escapement and the IsoSpring follow on from a series of breakthroughs made possible by the introduction of silicon parts in the early 2000s. Ulysse Nardin’s Dual Escapement and, more recently, Girard-Perregaux’s Constant Escapement with flexing blade are excellent examples. However, De Bethune is the only brand to have dared ditch conventional systems for its “Résonique” regulator. It differs from the IsoSpring in that there is no mechanical connexion; a magnetic rotor transfers energy to the oscillator. Unusually, De Bethune has published all its research on a blog launched at the same time as the project, with the as yet unfulfilled aim of encouraging other researchers to join in. Identical in principle but with different applications, the IsoSpring and Résonique could open up some serious new perspectives.