Tourbillon 24 Secondes

Caracteristics

Description

Tourbillon 24 Secondes

Twenty-four seconds to neutralise positional discrepancies

The race against gravity

Following up on the research and development work that led to the Invention of the Double Tourbillon 30° and the Quadruple Tourbillon à Différentiel Sphérique, inventor-watchmakers Robert Greubel and Stephen Forsey decided to draw upon the exclusive resources of the EWT® platform to take the exploration of the Tourbillon regulator in a different direction.

For their third fundamental Invention, they chose to use the unexplored possibilities of the rotating cage, opting for the high rotation speed of a uniquely inclined cage capable of performing a complete rotation in 24 seconds.

This high velocity combined with a 25-degree inclination of the cage enables the Tourbillon 24 Secondes Incliné to offer an innovative solution to the flaw in equilibrium by keeping the regulating mechanism’s exposure to the critical position to an absolute minimum – meaning that the balance and its spring are placed parallel to the earth’s surface.

While apparently simpler than Greubel Forsey’s first multi-axis constructions, this new solution in fact raised some tough new problems and required the inventor-watchmakers to draw upon all the mathematical and micro-mechanical engineering resources at their disposal in order to solve some very specific issues.


Apparent simplicity

One of the major problems caused by the cage’s high rotation velocity is the sheer inertia of the system, a high quantity of mechanical energy is required to start the cage, which advances in steps that are two and a half times greater than in conventional Tourbillon systems. Complex research was undertaken in order to reduce the weight of the mobile components to a minimum, and extremely low-density alloys already widely deployed in the aeronautical and aerospace industries were used.  Materials such as Avional and titanium, which have specific weights two to three times lower than that of steel, are perfectly suited to extreme use and made it possible to create a complete 88-part Tourbillon system weighing only 0.39 grams.

Another cutting-edge innovation incorporated within the Tourbillon 24 Secondes Incliné is a specially constructed inclined gear profile, optimising efficiency within the relatively small space of the mechanism. It ensures ideal meshing of the moving parts while eliminating any risk of binding. This array of improvisations has led to a significant increase in the performance of a single Tourbillon


Useful asymmetry

The off-centred mechanism principle underlying the architecture of the Tourbillon 24 Secondes Incliné have made it possible to enhance the visibility of the fast-rotating cage – another cherished Greubel Forsey quality. Both the lateral view afforded by the window in the central case band and the dial opening enable the viewer to admire the extreme angular velocity of the cage.