Here at Quill & Pad we are quite smitten by Romain Gauthier’s award-winning Logical One. The reason is clear: it comprises an incredible amount of technical elements that just can’t be seen anywhere else, all neatly and beautifully packed into a gorgeous parcel of mechanical beauty.

Sheer beauty: Romain Gauthier Logical One

And let’s not forget that exquisite finishing! (See Why Do Ultra-High-End Watches Cost So Much? Hand-Finishing At Romain Gauthier Sheds Some Light.)

Movement detail showing ruby bearings on constant torque chain of the Romain Gauthier Logical One

But one thing that gets glossed over somewhat is the subject of one of this watch’s four patents: the incredible high-precision chain made of synthetic ruby links. Combined with the snail cam, it is this element that provides the ingenious movement with constant force.

Gauthier registered a patent so that the intellectual property of this chain invention would be protected. His idea was to have a transmission chain for use in a watch movement exempt of the limitations that restrict the types of chains already in use, notably improving reliability and strength, ease of assembly and servicing, and reducing friction for more constant force and less maintenance.

Traditional cord and fusée mechanism highlighting how acute the angle can be when high on one side and low on the other

Until Logical One, chain and fusée mechanisms were avoided by many collectors because of the fragility of the chains. Gauthier decided he could do better and he did.

Gauthier’s approach

This may come as a surprise for some people, but Romain Gauthier is not a watchmaker.

Born and bred in the Le Sentier, he first trained as an engineer before managing the CNC department at a large component manufacturer in the Vallée de Joux, where his hometown is located. This was rather a valuable experience for someone planning to design and manufacture his own watches.

Assembling a patented ruby link constant force chain for Romain Gauthier’s Logical One

And make no mistake: Romain Gauthier’s business is a true manufacture in every sense of the word.

Coming from his engineering background, he thought it strange to have a high-precision machine forced to run at varying power levels like those produced by a standard mechanical movement’s mainspring. He began with the premise that a watch would run better and more precisely if it had constant energy, and he thought he could improve the vintage chain-and-fusée technology and come up with something worthy of the twenty-first century at the same time.

Assembling a patented ruby link constant force chain for Romain Gauthier’s Logical One

While the chain and fusée has the advantage of delivering fairly constant force, there are three significant disadvantages to the system: the tiny chains tend to be fragile; the fusée (French for “cone”) takes up a lot of space; and the fragile chain is often under tension at high angles, placing even more stress on the links.

Gauthier’s solution to all of these issues was to replace the fusée with a flat snail cam that takes up much less space in the movement, simultaneously ensuring that the chain is never pulling at an angle.

Assembling a patented ruby link constant force chain for Romain Gauthier’s Logical One

“My approach is one of a mechanical engineer,” Gauthier told me. “But I think if you ask a mechanical engineer to design a chain, they would most likely come up with something like a bicycle or motorbike chain: something very solid, not something like the chain you might usually find in a watch.”

He developed a whole new type of chain with links made of synthetic ruby, which not only makes it stronger than traditional chains – this corundum material is the second hardest known to man – but also additionally reduces both friction and wear and tear.

Assembling a patented ruby link constant force chain for Romain Gauthier’s Logical One

Synthetic ruby is the same material used to make bearing jewels.

“Compared to the chain of a traditional chain-and-fusée, my roller chain contains generously sized steel links, making the chain more solid. There are fewer links than a traditional chain, and fewer components mean something is less likely to go wrong,” Gauthier went on to explain.

Patented ruby link constant force chain for Romain Gauthier’s Logical One

“I harnessed the watchmaking principle of avoiding metal against metal by placing metal next rollers made of rubies. Rubies have a low coefficient of friction and high wear resistance. Finally, the chain is assembled and disassembled thanks to a snap-clip system, which facilitates maintenance.”

Gauthier’s snail cam and patented chain is just one of many ingenious mechanisms in Logical One.

Romain Gauthier Logical One in natural titanium with white fired-enamel dials

For more information, please visit www.romaingauthier.com/logical-one.

Quick Facts Romain Gauthier Logical One
Case: 43 x 14.2 mm, platinum, red gold, titanium, or ADLC-coated titanium
Movement: in-house manually wound manufacture caliber, 60-hour power reserve, push-button winding, chain-and-snail-cam constant force system
Functions: hours, minutes, small seconds; push winding
Price: from 98,000 Swiss francs

* This article was first published on March 11, 2017 at In Focus: Romain Gauthier’s Breathtaking Patented Ruby Link Chain From Logical One.

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