RM 62-01
AT THE CUTTING EDGE OF AIR TRAVEL & MECHANICS
Despite the difference in scale between a watch and an aircraft, we see these two objects as highly similar in terms of their functioning, requirements and processes. Thousands of hours spent on R&D are necessary for each one to see the day. Ultra-light and super-resistant materials ensure their solidity and performance. Sophisticated structural arrangements are chosen to ward off the intense vibrations they are subjected to. Uncompromisingly stringent certifications vouchsafe their durability. The meticulous application of fastidious procedures is a necessary condition of their quality. And their design aspect makes for marvellous machines that are a never-ending source of inspiration!
RM 62-01 TOURBILLON ACJ
CALIBRE RM62-01
Manual winding tourbillon movement with hours, minutes, oversize date, UTC (Universal Time Coordinated), am/pm indicator, function selector, power-reserve indicator.
Vibrating alarm function with on/off activation indicator.
Limited edition of 30 pieces in titanium and Carbon TPT®
POWER RESERVE
Circa 70 hours (± 10%), indicated at 11 o’clock
SKELETONISED BASEPLATE AND BRIDGES MADE OF GRADE 5 TITANIUM
The baseplate and the bridges are crafted of grade 5 titanium, a biocompatible, highly corrosion-resistant and remarkably rigid alloy, which enables the gear train to function effortlessly. The alloy is 90% grade 5 titanium, 6% aluminium and 4% vanadium. The use of grade 5 titanium combined with black PVD treatment lends the whole assembly great rigidity, as well as precise surface flatness. This combination further increases the material’s mechanical properties, which explains its frequent use in the aerospace, aeronautics and automobile industries.
The skeletonised baseplate and the bridges have been subjected to intensive and complete validation tests to optimise their resistance capacities.
VIBRATING ALARM
A new grand complication developed by Richard Mille with Audemars Piguet Le Locle, this specialist alarm is the result of five years of research and development. Its principle rests the automatic trigger, at the programmed time, of a vibrating signal produced by the rotation of an oscillating weight. Machined from a single piece of white gold, this weight is precisely calibrated to oscillate at 5,400 rpm.
Thanks to its dial and two hands, the alarm may be adjusted to the nearest minute of a full 24 hours, using the function selector situated at 3 o’clock. An on/off indicator at 5 o’clock completes the mechanism.
The maximum duration of the vibration, which has a dedicated barrel, is 12 seconds. It can be recharged by pressing a 12 times on the pusher at 8 o’clock. The power reserve can be viewed on a scale situated at 7 o’clock.
Words of Salvador Arbona, Technical Director - Movement
The project has been something of a marathon because it is extremely complex. It’s inspired by what we, amongst us, call ‘five legged sheep’, other extremely sophisticated movements such as that of the RM 039 Tourbillon Aviation, or the RM 25-01 Tourbillon Adventure Sylvester Stallone. These timepieces designed to take us into entirely new territory require mechanisms that entail many years of development. A vibrating alarm simply did not exist, so there was a very long phase of experimentation.
The project was aided by particularly close monitoring with APLL (Audemars Piguet Le Locle), with whom we develop and build movements of this type. Before building an entire movement, there were a variety of technical issues related to vibration within the heart of the movement that had to be resolved.
Four partial prototypes and tremendous work on the blueprints and the space limitations were needed in order to fit so many components and functions within a limited volume, in this instance equivalent to that of an RM 11-03. We had to find space for 816 components, 2 barrels, 7 hands, 11 displays and a tourbillon cage.
We spent a great deal of time pondering the following question: ‘Will the screws hold up against all these vibrations?’ We had to be certain, and to ensure it was so over time. Because, by definition, vibrations are the enemy of a movement. The multiple tightening operations are carried out using torque screwdrivers that make possible very precise calibrated forces based on studies with simulations and validation testing.
Also, the movement carries a Chronofiable® A8 certification, which vouchsafes a six month protocol of testing for shock-resistance, to be certain that no screws would loosen. Studies were undertaken at 50 and 100 g’s, while the movements were subjected to small, frequent shocks for 24 hours. This allowed us to decide on specific treatments for certain screws and to determine the optimal torque.
5-POSITION FUNCTION SELECTOR
A pusher located at the centre of the crown makes it possible to select among five different functions with a simple push: winding, hand setting, alarm setting, UTC setting and neutral position.
A disc at 3 o’clock displays the selected mode against a light-coloured ground: N (Neutral) — W (winding) — T (time setting) — U (UTC hand setting) — A (Alarm setting).
AM/PM INDICATOR
Located at 6 o’clock is a disc indicating whether the time displayed is Ante Meridiem (AM) or Post Meridiem (PM).
OVERSIZE DATE DISPLAY
Semi-instantaneous, placed in a red outlined horizontal aperture under 12 o’clock.
FREE-SPRUNG BALANCE WITH VARIABLE INERTIA
The free-sprung balance at 9 o’clock offers increased reliability in the event of shocks and movement assembly or disassembly, thus achieving better chronometric results over time. The index has been eliminated, allowing more precise and repeatable adjustment using 4 setting screws.
WINDING BARREL TEETH AND THIRD-WHEEL PINION WITH CENTRAL INVOLUTE PROFILE
The wheel with a central developing profile and a pressure angle of 20° promotes rolling movement more effectively by compensating for variations in gear engagement, thus ensuring excellent torque transmission with a distinct improvement in performance.
MOVEMENT CHARACTERISTICS
- Movement dimensions: 31.92 x 31.99 mm
- Thickness: 7.75 mm
- Tourbillon diameter: 12.30 mm
- Balance wheel diameter: 10.00 mm
- Jewels: 77
- Balance: Glucydur®, with 2 arms and 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 in nickel-free Chronifer® (DIN x 46 Cr 13 + S), with the following characteristics: stainless – antimagnetic, suitable for tempering
CASE MADE OF TITANIUM AND CARBON TPT®
The caseback and bezel are comprised of a first bezel in polished and satin-finished grade 5 titanium, to which is affixed a second bezel, just 1.80 mm in thickness, machined from Carbon TPT®. This high-tech material is made up of 600 layers of parallel filaments obtained by separating out carbon fibres. The layers, no more than 30 microns thick, are impregnated with a black resin. They are then assembled on a dedicated machine, which stacks the layers, varying the orientation of the fibres by 45° between layers. The composite is then hardened heated to 120°C at a pressure of 6 bars in a kiln similar to that used for the production of aeronautics parts, after which it is ready to be machined at Richard Mille. During this phase, the many layers of Carbon TPT® are revealed, creating random damascene patterns that make each piece unique.
The caseband and pushers are also milled from Carbon TPT® enhanced with stiffeners in microblasted and polished grade 5 titanium. The case is assembled with 20 Torq-Set® screws in grade 5 titanium and abrasion-resistant washers in 316L stainless steel.
TORQ-SET® SCREWS FOR THE CASE
Like the blades of a propeller, the four arms that characterise a Torq-Set® screw head converge on the centre in an offset cruciform manner with curved trajectory. This type of screw is employed in the aerospace industry to ensure optimal control and transmission of torque. Superior to a traditional Phillips screw, its form also ensures flawless positioning for quick assembly and disassembly under any conditions.
TORQUE-LIMITING CROWN
The crown incorporates a special security system to prevent accidental overwinding, which could cause damage to the winding stem or place extreme pressure
Finishing
Movement
- Hand-polished bevelling
- Hand-polished locking-sections
- Sunray brushing finishing on bridges
- Sapphire-microblasted milled sections
- Lapped and polished contact points
- Burnished pivots
Steel parts
- Sapphire-blasted surfaces
- Anglage and polishing by hand
Wheels
- 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.
Other features
FAST-ROTATING BARREL (6 hours per revolution instead of 7.5 hours)
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.
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.
SPLINE SCREWS IN GRADE 5 TITANIUM FOR THE BRIDGES
This permits better control of the torque applied to the screws during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well.