The PulsomaxR is the first escapement developed in its entirety by Patek Philippe. It features the same reliability and robustness for which the classic Swiss lever escapement has long been appreciated. However, its efficiency is vastly improved due to its unique geometry. To optimize the functionality of the new escapement, Patek Philippe tapped into the free-forming capabilities and high precision of the DRIE deep-etching process in silicon machining applications. With its latest developments based on this technology, Patek Philippe was able to significantly improve the performance of mechanical movements, opening up new dimensions in watchmaking.
With its combination of a PulsomaxR lever and escape wheel made of SilinvarR and a SpiromaxR balance spring made of SilinvarR, Patek Philippe can now present the third generation of watches within the scope of the “Patek Philippe Advanced Research” concept: the limited-edition Annual Calendar Ref. 5450 in platinum. It embodies a patent-pending innovation that considerably improves the beat accuracy and long-term reliability of mechanical movements.
Six years ago, Patek Philippe began to explore potential applications for silicon in the domain of watchmaking.
To optimally exploit the multiple advantages of this material, the manufacture developed new proprietary geometries for silicon components that further optimize the functional of individual escapement parts and dramatically boost the long-term performance of mechanical calibers.
The results of this research work with the SilinvarR material so far are an escape wheel and the SpiromaxR hairspring with the Patek Philippe terminal curve. These SilinvarR parts had their debut with two limited-edition Annual Calendar wristwatches: the Ref. 5250 was launched in 2005 and the Ref. 5350 in 2006.
These two watches presented under the “Patek Philippe Advanced Research” label give collectors and high-tech aficionados the opportunity to be the first to participate in trailblazing technological developments.
In-depth analyses under laboratory and real-world conditions as well as the reports of owners of “Patek Philippe Advanced Research” watches were so encouraging that Patek Philippe decided to pursue the development of silicon-based components. Every development step so far has yielded significant and measurable improvements of the performance of mechanical watches:
• 2005 Escape wheel made of SilinvarR for a Swiss lever escapement:
Enhancement of reliability without lubrication
• 2006 SpiromaxR balance spring made of Silinvar, with Patek Philippe curve:
optimization of rate with significantly improved isochronism
(concentric expansion and contraction of the spring)
SilinvarR stands for revolutionary progress in silicon technology
The patented SilinvarR material is obtained from pure silicon in a patented vacuum oxidation process that produces a molecular change on the surface of the silicon components.
This molecular change endows silicon watch components with the properties that are essential for the rate accuracy of a mechanical movement. Contrary to pure silicon components, SilinvarR parts have a temperature-compensating characteristic, a very important and advantageous property for oscillating parts.
Moreover, SilinvarR has no surface coating that could become defective in time.
All silicon components in the Patek Philippe Advanced Research watches crafted so far are made of this unique, patented SilinvarR material.
PulsomaxR – the innovative escapement made of SilinvarR
Patek is now premiering the PulsomaxR, an entire escapement – the escape wheel and the lever – made of SilinvarR.
Nevertheless, the PulsomaxR is a Swiss lever escapement in every respect. For nearly 180 years, almost all compact mechanical movements have been fitted with this type of escapement. It owes its popularity to dependability, ruggedness, and a high level of efficiency.
Thanks to high-precision machining technologies, the SilinvarR lever no longer needs to be fitted with ruby pallets. Patek Philippe has enlarged the integrated pallets to boost the efficiency of the new escapement. The redesigned lever can transmit more power to the balance. Contrary to conventional levers, the two integral pallets of the SilinvarR lever have differentiated shapes that raise the efficiency of each escape cycle. The new lever also influenced the geometry of the escape wheel, which now has 16 teeth instead of 20, as was formerly the case.
The SilinvarR escape wheel presented in 2005 was still designed to interact with the geometry of a steel lever with ruby pallets. Now, the new PulsomaxR escapement features both a lever and an escape wheel with significantly optimized geometries.
Enhanced-functionality lever design thanks to innovative DRIE process
Because further progress has been made in deep reactive ion etching (DRIE) technologies, silicon parts can now also be machined on a second horizontal plane in an extra process. This enabled a totally new design of the fork that no longer needs to be fitted with a receiver block for a guard pin. Instead, the ends of the fork horns are closed with a recessed bridge that functions like a guard pin (1). It prevents random displacements of the lever fork as the balance wheel passes through the supplementary arc.
The geometric changes in the design of the integrated entry and exit pallets are extensive as well. Because the precision of the DRIE manufacturing processes is extremely high – with tolerances twice as tight as those for ordinary steel parts – shapes and dimensions can be controlled with such a degree of accuracy that totally new functions can be implemented with a novel geometry approach.
One of these functional advantages is the elimination of the detent pins or the solid banking elements – so-called etoqueaux (2) – that limit the angular deflection of the lever. Apart from a slightly recessed locking face (3), the pallets of the PulsomaxR lever feature with a second function plane. This return face (4) together with the locking face (3) forms a locking notch (5) in which the heel (6) of the tooth of the escape wheel is positioned. This blocks the lever and clearly defines not only its position but also the position of the heel of the escape wheel tooth on the locking face (3). The position of the heel, also called penetration, is extremely important, because if it is too shallow or too deep, this has a direct impact on the function and thus on the efficiency of the escapement. It was also found that the innovative geometry and the high precision of the PulsomaxR parts reduces the angle of lift deviations of the balance by half. This factor positively influences the amplitude. In other words, the position of the locking notch in the locking face enhances the precision of adjustments and the rate accuracy of the watch.
The PulsomaxR escapement gives Patek Philippe yet another opportunity to demonstrate its leadership in horological technology. It is unquestionably the most advanced Swiss lever escapement in terms of efficiency. Together with the SpiromaxR balance spring, the new escapement delivers perceptible long-term improvements and measurable performance gains in mechanical movements.
• 2008 PulsomaxR escapement with SilinvarR lever and 16-toothed escape wheel combined with a SpiromaxR balance spring.
Increase of reliability without lubricants
Rate accuracy optimization based on improved isochronism
Increase of efficiency of the Swiss lever escapement
Increase of power reserve by 30% due to enhanced efficiency of the escapement (a watch with a power reserve of 48 hours will now run for 62 hours)
Result: greater amplitude stability, long-term improvement of the rate accuracy of the watch
The third Patek Philippe Advanced Research generation: an Annual Calendar with the innovative PulsomaxR escapement and the SpiromaxR balance spring
For quite some time now, the assembly with the SpiromaxR balance spring and the PulsomaxR escapement (lever and escape wheel) made of SilinvarR has been integrated in a number of prototypes worn regularly by Patek Philippe staff members, among them by President Philippe Stern. He is enthusiastic about his priceless, one-of-a-kind timepiece that never ceases to amaze him: never before in his career has he seen a mechanical wristwatch with such a rate accuracy.
This “president’s watch” will no doubt some day occupy a prestigious position in the Patek Philippe Museum, testifying to a revolutionary development with which the manufacture succeeded in once again measuring the passage of time a bit more precisely.
After several years of successful laboratory and real-life tests with the PulsomaxR escapement, Patek Philippe will gradually integrate this innovation in its regularly produced timepieces. However, connoisseurs and collectors of horological rarities have the opportunity to experience this milestone in horological history before the year comes to an end. In a third “Patek Philippe Advanced Research” edition limited to 300 watches, the Geneva workshops are presenting the Ref. 5450 at Baselworld 2008. As earlier limited editions with silicon-based components, the new watch is an Annual Calendar. The Ref. 5450 features a platinum case and a movement with a PulsomaxR escapement and a SpiromaxR balance spring.
Technical data
Patek Philippe, Ref. 5450 in platinum
Movement:
Caliber 324 S QA IRM LU
Self-winding mechanical movement, Annual Calendar, moon phase and power-reserve indicator
Diameter: 32.60 mm
Height: 5.78 mm
Number of parts: 356
Number of jewels: 34
Power reserve: Min. 50 hours. Max. 60 hours
Winding rotor: 21K gold central rotor, unidirectional winding
Balance: Gyromax
Frequency: 28,800 semi-oscillations per hour (4 Hz)
Balance spring: SpiromaxR
Escapement: PulsomaxR (Silinvar R lever and escape wheel)
Functions:
Two-position crown:
- Pulled out: to set time
- Pushed in: to wind watch
Displays: Hours, minutes, power-reserve indicator at 12 o’clock and sweep seconds
Subsidiary dial:
- Day of week at 9 o’clock and month at 3 o’clock
Apertures:
Date at 12 o’clock, moon phase display at 6 o’clock
Corrector buttons:
• At 10 o'clock: day-of-week correction
• At 2 o'clock: month correction
• At 4 o'clock: date and month correction
• At 8 o'clock: moon-phase correction
Included: correction stylus in ebony and 18K white gold
Hallmark: Geneva Seal
Features
Case:
Case in platinum 950, water-resistant screw-down crown
Water-resistant to 30 meters
Hallmark: Screwed sapphire-crystal case back, with an integrated loupe and the inscription “Patek Philippe Advanced Research” engraved in the crystal
Case dimensions:
Diameter: 39 mm
Thickness: 11.70 mm
Width between lugs 20 mm
Dial: Rose
Three applied Arabic numerals in 18K white gold, straight Breguet style, at 3, 9, and 12 o’clock
Eight applied baton-style indices in 18K white gold
Leaf-shaped hour and minute hands in black nickel-plated white gold with luminescent coating
Leaf-shaped day, month, and power-reserve hands in black nickelplated gold
Counterbalanced seconds hand in black nickel-plated gold
Railway track minute scale transfer-printed on dial perimeter
Twelve luminous pearldrop hour markers
Strap: Alligator with rectangular scales, shiny hazelnut, hand-stitched, with fold-over clasp in platinum
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