A talented watch designer, Eric Coudray practises his art at Tec-Group in Vallorbe. He has named his triaxial tourbillon Spherillon in order to simply define its main technical specificity. Proven efficiency!
By Vincent Daveau, watchmaker & journalist, historian
To be read on the Swiss Watch Journal JSH® – June 2021 Issue
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Giving inventions names that describe their main characteristics is a pragmatic approach that has been part of watchmaking logic since its origins.
The importance of defining terms
In 1801, Abraham-Louis Breguet named his regularly rotating cage “tourbillon” to cancel out any equilibrium defects in the regulating organ enclosed within, because this component seemed to whirl once the watch was running. As Eric Coudray, the creator of the Gyrotourbillon for Jaeger-LeCoultre, said, this spherical regulating organ should never have been given such a name, because the amateurs who have seen it, intellectually assimilate this bi-axial tourbillon regulator to a gyroscope. However, this is not the case. To avoid confusion, this genius designer has therefore chosen to name his new invention “Spherillon”. It is a contraction in French of the words “sphere” and “tourbillon”.
For him, things are clear: his three-axis tourbillon, in which he has installed a regulating group with a Potter escapement (anchor wheel with inverted teeth), must allow the cage containing the balance wheel to rotate in just 8 seconds. This device, already used by Franck Muller in 2012, is used again here to guarantee both an original construction and optimised operation.
Technical and team challenge
As Eric Coudray points out, the initial idea behind the Spherion was to design a new type of multi-axis controller on paper, as one would do with an exercise. But Arnaud Faivre, the founder of Tec Group, sold the concept to Purnell and MB&F and it was necessary to move from the idea to the finished product. The creator confides: “I have to admit that this rather original escapement caused us a few problems because we had to find the right efficiency and the optimal rotation speed to transmit enough energy to the balance…”
… but the watchmakers impressed me and managed to find the best balance for this three-axis tourbillon cage”.
Au final, la précision est très bonne et la compensation excellente, car l’organe réglant décrit bien une sphère à la fin d’une révolution complète de l’organe. C’est la condition sine-qua non pour qu’un tourbillon ait un sens sur une montre-bracelet et produise les mêmes effets positifs qu’un tourbillon classique monté dans une montre de poche.
In the end, the precision is very good and the compensation excellent, because the regulating organ describes a sphere at the end of a complete revolution of the organ. This is the prerequisite for a tourbillon to make sense on a wristwatch and produce the same positive effects as a classic tourbillon mounted in a pocket watch.
And Eric Coudray concludes: “If the pivots of the balance axis draw a perfect sphere in space when the organ containing it is in motion, the latter must bear the name of the shape it produces in order to allow amateurs to better understand the kinematics of this marvel of meticulousness. Really, why make it complicated when you can make it simple. So I called this body the Spherillon because it makes everything clear.” That’s it, Mr Coudray!
