CREATED FOR EXTREME CONDITIONS
RM 025 TOURBILLON CHRONOGRAPH DIVER'S WATCH
Manual winding tourbillon movement with hours, minutes, seconds, chronograph, 30-minute totaliser, power-reserve indicator, torque and function indicators.
Circa 50 hours (± 10%), 45 hours without chronograph running.
Actual power reserve results will depend on chronograph usage.
CARBON NANOFIBRE BASEPLATE
This is an isotropic composite material created from carbon nanofibres moulded under a pressure of 7,500 N/cm2 at a temperature of 2,000˚C, resulting in a material with high mechanical, physical and chemical stability in all directions.
The ribbed perimeter of the movement’s baseplate ensures optimal rigidity of the baseplate and bridges.
Carbon nanofibre composites such as this are amorphous, chemically neutral and dimensionally constant within a very wide range of operating temperatures, including those outside of normal experience. This stability ensures the greatest possible integrity of the movement’s going train under all conditions.
Grade 5 titanium is a biocompatible, highly corrosion-resistant and remarkably rigid alloy composed of 90% titanium, 6% aluminium and 4% vanadium. This combination further increases the material’s mechanical properties, which explains its frequent use in the aerospace, aeronautics and automobile industries.
The modern architecture of this movement allows the consistent and rational arrangement of its constituent parts, avoiding unnecessary superimpositions and permitting the best possible use of available functions thanks to technical solutions. For example, research was conducted into the geometric design of the column wheel that controls the different levers to ensure the perfect, long-term simultaneity of the functions, a feature essential for a high-performance split-seconds chronograph. This design was implemented in order to achieve a high degree of continuity in the settings with an unfailing repeatability of functions.
In a manner similar to a car’s gearbox, the function indicator makes it possible to identify the winding, neutral and hand-setting positions as the crown is pulled out. The active position is indicated via a hand at 4 o’clock that indicates the function as follows: W (Winding) – N (Neutral) – H (Hands).
This indicator supplies information about the mainspring’s tension, thus permitting an optimisation of the movement’s chronometric functioning. Below 5.3 N.mm, the spring is considered too slack, while above 6.5 N.mm, excess tension in the spring can adversely affect the mechanism’s operation, or actually endanger it.
The power-reserve indicator shows the number of hours of energy left in the mainspring before the watch must be wound again.
The free-sprung balance offers better reliability in the event of shocks, movement assembly or disassembly, and also guarantees better chronometric results over time. The regulator index is eliminated, and a more accurate and repeatable calibration is possible thanks to 4 small adjustable weights located directly on the balance.
This type of barrel provides the following advantages:
• The phenomenon of periodic internal mainspring adhesion is significantly diminished, thereby increasing performance.
• Provision of an excellent mainspring delta curve with an ideal power reserve/performance and regularity ratio.
Movement diameter: 38.95 mm
Thickness: 8.12 mm
Tourbillon diameter: 12.30 mm
Number of jewels: 30, set in white gold chatons
Balance: Glucydur®, 2 arms, 4 setting screws, moment of inertia 10 mg•cm2, angle of lift 53°
Frequency: 21,600 vph (3 Hz)
Balance spring: elinvar by Nivarox®
Shock protection: KIF Elastor KE 160 B28
Barrel shaft: nickel-free Chronifer® (DIN x 46 Cr 13 + S) with the following characteristics: stainless – antimagnetic – suitable for tempering
The watch is water resistant to 30 atmospheres (300 metres) per ISO 6425 diver’s watch norms. This is achieved within a unique, curved, tripartite case design using torque screws that can be individually and precisely tensioned with great accuracy around the exterior circumference of the case. This is complemented by a screw-lock crown construction. The lugs of all versions are made of grade 5 titanium, with screws to attach the rubber diving strap for maximum security.
This component is constructed of three layers, connected using 22 screws, and turns unidirectionally per ISO 6425 norms to avoid timing miscalculations. The use of an additional screwed system attaching the bezel to the watchcase makes it absolutely stable, as well as impossible to inadvertently dislocate or loosen. In addition, the use of screws makes possible perfect adjustment since the bezel is not tensioned into position.
For clearer visibility under murky conditions, starting at 12 o’clock, the five-minute markers of the first quarter are highlighted in red.
This additional security system prevents accidental overwinding, which could cause damage to the winding stem or place extreme pressure on the barrel spring.
• Anglage and polishing by hand
• Hand-polished locking sections
• Sapphire-blasted milled sections
• Lapped and polished contact points
• Burnished pivots
• Sapphire-blasted surfaces
• Anglage and polishing by hand
• Concave chamfering with a diamond tool
• Circular-finished faces
• Rhodium plating (before cutting the teeth)
• Minimal corrections applied to the wheels in order to preserve geometry and performance.
BARREL PAWL WITH PROGRESSIVE RECOIL
This device permits an appreciable winding gain (circa 20%), especially during the start of winding. It is also helpful in evenly distributing the mainspring’s internal tension.
WINDING-BARREL TEETH AND THIRD-WHEEL PINION WITH CENTRAL INVOLUTE PROFILE
The central involute profile of the winding-barrel teeth provides an optimal pressure angle of 20°, which promotes effective rotary motion and compensates for possible variations in the operation of the going train. This, in turn, ensures excellent torque transmission and a distinct improvement in performance.
SPLINE AND EIGHT-POINTED SCREWS IN GRADE 5 TITANIUM FOR THE BRIDGES AND CASE
These types of screw permit better control of the torque applied to screws during assembly. These screws are unaffected by physical manipulation during assembly or disassembly and age well.