2013/07/30

Greubel Forsey the Quadruple Tourbillon Secret in 5N Red Gold

 

A Unique Edition of eight timepieces in 5N red gold

With its full dial concealing the intricate ballet of a quartet of tourbillons below, the Quadruple Tourbillon Secret offers the ultimate in discretion and refinement. Behind the blackened gold dial. An exceptional movement with superlative fine finishing features two double tourbillon systems linked by a spherical differential playing out a micro-mechanical ballet. Hinted at by the sub-dial indications, but visible only through the lateral window on the case band and through the display back.

While the 18k gold skeletonised hour and minute hands, GF logo, applied 12, hour indexes and individually numbered plate first attract the eye due to their high-contrast juxtaposition against the blackened gold background, it is the two lower sub-dials –the one at 7 o’clock doubles as a bridge − covering the double tourbillons that hint at the complexities below.

The larger small seconds dial near 7/8 o’clock shows 240 seconds, which is the 4-minute rotation of the outer double tourbillon cage, while the small seconds at 5 o’clock indicates the 4-minute rotation of the second double tourbillon cage. A high-performance spherical differential links the two double tourbillon systems and supplies an average rate to the gear train. Small seconds with the sectorial power reserve indicator at 2 o’clock displays the averaged rate of the two inclined balance wheel oscillators.

With its precision choreography artfully concealed, the Quadruple Tourbillon Secret represents a special personal link for the collector with Robert Greubel and Stephen Forsey. Exclusivity is assured by a unique edition of eight pieces in 5N red gold and eight pieces in platinum.

Technical data
The movement comprises 519 components, 261 of which make up the four tourbillon cages, it is powered by two mainspring barrels which provide an optimal power reserve of 50 hours. The oscillators feature variable inertia balance wheels, Phillips terminal curves and beat at 3Hz/21,600 vibrations per hour.

The plates and bridges are in nickel silver finished in nickel-palladium with hand polished bevels, spotted and straight-grained finishes and. The main dial is in blackened or silvered gold with applied indices. The case is available in platinum 950 or 5N red gold and measures 43.5 mm in diameter by 16.11 mm high and features asymmetrical domed synthetic sapphire crystals on the dial side and for the display back. The black alligator strap is hand stitched with a folding clasp in platinum 950 or 5N red gold to complement the case.

Quadruple Tourbillon
The Quadruple Tourbillon was Greubel Forsey's second Fundamental Invention and features four tourbillons – composed of two Double Tourbillon 30° systems  – working independently in pairs and linked by a spherical differential that transmits the average of their rates to the gear train and time display. In this world-premiere construction, the double tourbillons with their separate 30° inclined balances, which are generally on completely different planes, average-out gravity-induced errors on the balance and spring oscillator, to improve timekeeping. This construction allows for superior chronometric performance for a minimum volume/maximum balance diameter ratio.

Spherical Differential
The two double tourbillons regulators are linked by a spherical differential that transmits the average of their rates to the gear train and indications. While flat differentials are a regular feature of timepieces (usually in conjunction with power reserve indicators), spherical differentials (like those used in cars) are extremely rare due to the difficulty of manufacturing their complex components.

Fine Finishing and Aesthetics
As with all GreubelForsey timepieces, the level of hand-finishing and decoration throughout the Quadruple Tourbillon Secret is without compromise. Movement components are designed with forms that bring out their beauty to maximum effect, offering myriad sublime details to be discovered and esteemed. Frosted plates, blackflat polished steel and stunning hand-polished bevels with sharp internal angles (which machines cannot do as well as a highly experienced hand) bring unparalleled vivacity. Large jewels set in polished gold chatons, and mirror-polished screws provide evidence of the extremely high quality that pervades every aspect of this timepiece.

 

Quadruple tourbillon à différentiel sphérique

Extraordinary choreography
Thanks to this uncompromising creation, Robert Greubel and Stephen Forsey have reaffirmed themselves as authentic inventors, using the mechanical timepiece as their means of expression.

The Quadruple Tourbillon à Différentiel is a blend of art and technical innovation which encapsulates the very soul of its the two creators.

Asymmetrical balance
Robert Greubel and Stephen Forsey have engineered the four Tourbillons together in a contemporary design, in which elegance and harmony are the dominant features.

In the same spirit, and owing to the impressive number of parts which make up the movement, an asymmetrically-shaped case was chosen. The asymmetrical form was also an aesthetic tribute to the asynchronicity of the four Tourbillons.

With its sophisticated coalescence of technical Invention and artistic design, the Quadruple Tourbillon à Différentiel encapsulates the best in fine watchmaking.

Wearing a Quadruple Tourbillon à Différentiel is to enter the universe of Robert Greubel and Stephen Forsey, and to share, appreciate and be empathetic to the essential values emanating from their Invention.

 

ex. : Model Quadruple Tourbillon

In the Secret version, the tourbillon cage is turned upside down, so the construction of the movement is a little bit different. This was done as, being the two tourbillon cages, visible only from the case back, you can see on one cage the top and on the other the bottom of the tourbillon cages.