Greubel Forsey Invention Piece 2 : Homage to Quadruple Tourbillon – 5N Red Gold/950 Platinum Case

Swiss luxury watch brand Greubel Forsey is famous for its significant inventions, and the Invention Pieces are special horology creations made to honour its own master piece complications. In 2007, Greubel Forsey introduced the Invention Piece 1 to pay homage to the Double Tourbillon 30° and in 2009, Invention Piece 3 honoured the Tourbillon 24 Secondes. This year, the Swiss haute horologerie brand introduces Invention Piece 2 to pay tribute to the Quadruple Tourbillon with a completely new architecture in which the focus is on its exclusive mechanism.

The two double tourbillons systems are presented head to tail and coupled by a spherical differential. A sub-dial at 5 o’clock conceals triple mainspring barrels and features a red triangle indicating hours and a rotating disk indicates minutes. Small seconds dial at 10 o’clock and 56-hour power reserve indicator at 11 o’clock complete the dial. Unveiled first time at SIHH 2011, the Invention Piece 2 is available in limited edition of 11 pieces in platinum and 11 in red gold.

Technical details
Movement
Mechanical hand-wound movement, Calibre GF03n. Movement with patented tourbillon. Quadruple Tourbillon, hour and minute display, small second indicator, power-reserve indicator.

Movement dimensions
• Diameter: 37.0 mm
• Cage diameter: 36.40 mm
• Thickness : 11.87 mm

Number of parts
• Complete movement: 594 components
• 1 double tourbillon cage: 129 components
• Weight of one double cage: 1.17 g
Number of jewels: 64 Olived-domed jewels in gold chatons

Power reserve: 56 hours
Barrels: Rapid rotating triple barrels (1 turn in 3.2 hours), equipped with a slipping spring to avoid excess tension
Balance wheel: Free sprung balance with white gold mean-time screws (10.70 mm diameter)
Frequency: 21’600 vibrations/hour
Balance spring: Phillips terminal curve, Geneva-style stud
Main Plates: Nickel silver, spotted nickel-palladium finish, hand bevelled, straight-grained flanks, polished counter-sinks

Bridges
• Nickel silver bridge, frosted, spotted with polished bevelling, nickel-palladium finish
• Gold nameplate bearing the individual number of the timepiece
• 4 steel Double Tourbillon bridges hand-bevelled, flat black polished with polished counter-sinks

Gearing
• Involute circle profile
• Conical gearing with corrected profiles

Inner Tourbillon
Inclined at a 30°angle, 1 rotation per minute

Outer Tourbillon
• 1 rotation in 4 minutes
• Hand-bevelled and openworked cage pillars
• 1 gold Greubel Forsey counterweight per cage

Displays
• Hours and minutes
• Small seconds sub dial (mean performance)
• 56-hour power reserve on a sector
• Tourbillon rotation sapphire crystal indicator (outer cage) in 4 minutes at 1 o’clock

Case
• Platinum 950 or 18k 5N red gold with asymmetrical convex sapphire crystal
• Transparent back with asymmetrical convex sapphire crystal
• Lateral window with shaped sapphire crystal
• Gold security screws
• Polished bezel and centre band with hand-finished straight graining
• Hand-engraved individual number
• Raised engraving of the name of the Inventors on a hand-punched background
• Unique edition of 11 pieces in platinum and 11 pieces in 5N red gold
• Diameter: 43.50 mm
• Thickness: 16.28 mm
Water resistance of the case: 3 atm – 30 m – 100 ft
Crown: Platinum or 5N red gold with engraved and black lacquered GF logo

Dial
• 22k gold hour indicators with red triangle
• 22k gold Greubel Forsey initials in centre

Hands
• Minute-indicator: rotating disc with fi xed blue triangle
• Small second in flame-blued polished steel
• Power-reserve in flame-blued polished steel
• Sapphire crystal 4-minute indicator

Strap and clasp
• Hand-sewn black alligator
• Platinum 950 or 18k 5N red gold folding clasp, hand-engraved with the Greubel Forsey logo

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