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23
06

PIERRE GENEQUAND, INVENTOR OF THE SENFINE

The Senfine adventure began in the mind of one man, an inventor: Pierre Genequand. Here is a quick overview of this physicist's journey, the history of his idea and the circumstances that gave rise to it.

MULTIDISCIPLINARY INVENTOR AT BATTELLE

As soon as he had completed his degree in physics, Pierre Genequand knew that his career would centre on applied physics, as practised by engineers and inventors, rather than abstract theoretical physics. After obtaining a doctorate in technical sciences from the EPFL, he took up his first position at Battelle, an American research institute with offices in Geneva. Researchers such as Pierre Genequand create and come up with inventions or patents for external clients. This way of working forces them to become generalists, or rather "specialists in every field"; it promotes versatility as opposed to narrow specialisation, ensuring they adopt a self-taught and, above all, highly creative approach. Pierre Genequand worked at the Battelle Institute from 1970 to 1982.

 

CAREER AT THE CSEM AND FLEXTECH TECHNOLOGY

In 1982, during the watchmaking crisis, Pierre Genequand was employed by the Fondation Suisse de Recherche en Microtechnique (Swiss Foundation of Microtechnological Research) in Neuchâtel – a recently formed foundation aiming to promote technological diversification. He helped to develop the microshutter printer, derived from the microshutter watch display, a project based on flexible joints. The technology – dubbed "FlexTech" – uses silicon to form structures that allow flexible movement without friction or energy loss.

In 1984, Pierre Genequand was transferred to the CSEM, the Swiss Centre for Electronics and Microtechnology, where he continued his work on flexible joints and became aware of the extent of their potential. These joints or glides operate without producing friction, wear, or the slightest play, meaning that every movement is completely repeatable as well as being unerringly precise. They require no lubrication, present no risk of jamming in a vacuum and are therefore suited to instruments that operate for a long time without maintenance – typically space instruments. These features enabled Pierre Genequand to develop inventions such as a telescope mirror suspended on a FlexTech stem, which enabled a laser beam to be created between two satellites separated by 20,000 km of space. Such is the precision of FlexTech.

Pierre Genequand became an uncontested specialist in the field of aerospace and FlexTech technology, which he used on a daily basis during his entire career at CSEM. His mastery of flexible guides would be the first key to his invention. The second was the watchmaking history that CSEM is steeped in.

 

CSEM - BUILT ON WATCHMAKING LEGACY

CSEM was formed in 1984 by a merger between three Neuchâtel companies specialising in microtechnology. Two of these focused solely on watchmaking (Centre Electronique Horloger and Laboratoire Suisse de Recherches Horlogères) and these have had a considerable influence on the CSEM since its creation.

Pierre Genequand's professional development therefore took place within a company with considerable watchmaking heritage, which piqued his curiosity in the field. Around 1995, silicon micro-mechanical projects began to be developed for the watchmaking industry using plasma micromachining of silicon. Pierre Genequand wanted to contribute to this movement. At first, it was the extensive CSEM library that quenched his thirst for learning. Using his autodidact skills gained during his career at Battelle, he obtained a treatise on watchmaking and photocopied its four hundred pages so that he could read and annotate them and assimilate their content. This was how Pierre Genequand acquired his basic watchmaking knowledge, the essential foundation for his invention.

After retiring in 2002, Pierre Genequand was able to devote time to the question that had taken root in his mind: Could silicon and FlexTech technology – which he knew so well – be applied to watchmaking?

 

THE STAGES OF THE INVENTION

With his trove of self-taught knowledge, Pierre Genequand focused on the energy consumption of the watch's movement. The efficiency of its escapement was no greater than 40%, which presented definite potential for improvement.

During his first attempt, Pierre Genequand replaced the traditional escapement of the watch regulator with a constant contact escapement with flexible pallet stones made from silicon. He estimated that its efficiency would be over 80%. However this improvement was simply not enough to justify the isochronism corrector which would have to be introduced because of the constant contact of the escapement. Pierre Genequand then decided to push his reasoning even further by introducing structures with flexible guides into the pallet fork and balance; by positioning the balance using flexible suspension, thereby eliminating all points of friction; and by using the oscillation amplitude limitation that forms part of FlexTech technology to his advantage to work at the appropriate frequency. Removing all of the pivots and tackling every point of friction led to at least a fivefold reduction in the energy consumed by the balance, with the overall improvement being a tenfold reduction. The lack of isochronism was considerably lessened and the power reserve could be extended to months rather than days.

Paradoxically, Pierre Genequand's strength – aside from his inexhaustible creative genius – was the fact that he never worked as a watchmaker. To be able to stray from the beaten path, one must have the wide-eyed belief of the relatively inexperienced. Watchmakers are compelled to follow a strict discipline that favours isochronism above all. To the watchmaking world, a constant contact escapement such as the one developed by Pierre Genequand may seem sheer madness. The constant contact means that the balance does not oscillate freely, creating a lack of isochronism in the system and consequently breaking the golden rule. Unfettered by these constraints simply because he was not aware of them, Pierre Genequand created the first revolution in watch regulating organs in two hundred years of stability. The Senfine is an unprecedented invention in the watchmaking world.