Urban Jürgensen & Sønner P8 Chronometer Ref. 11C Automatic

Swiss luxury watch brand Urban Jürgensen & Sønner presents P8 Chronometer Ref. 11C Automatic, a world premier model equipped with the first automatic movement to ever integrate a pivoted detent escapement within a wristwatch. The first model in the P8 Chronometer line was P8 Reference 11L launched in 2011, which featured a Swiss lever escapement. The new Ref. 11C Automatic model features a patented pivoted detent escapement.

The newly introduced Urban Jürgensen Reference 11 represents the first time that the chronometer escapement has been used in a wristwatch. The invention is the result of several years’ development work and has been patented world wide. In the past 25 years, in addition to individual, often complicated unique watches, Urban Jürgensen & Sønner also created wristwatches in small series from 50 up to a maximum of 300 examples. These watches were mainly based on ébauche movements from Frédéric Piguet, Le Brassus.

The long-held wish for a true UJS movement, with strong emphasis on precision, reliability and long intervals between servicing, has been addressed since 2003. In the 19th century, Urban Jürgensen & Sønner was the official chronometer maker to the Danish Royal Household and to the Admiralty. The quality of the marine chronometers from the house of Jürgensen was legendary. In order to close the loop from the past to modern times in an elegant and meaningful manner, development of a new movement and the chronometer escapement, suitable for use in a wristwatch, was undertaken. A particular problem was to ensure the necessary shockproof characteristics of the escapement. Having achieved this, the invention was patented on a world-wide basis by Urban Jürgensen.

The new movement UJS P8 is introduced to the market in two versions. The first model was with a traditional Swiss lever escapement and the second with the newly introduced detent escapement, a “first” in wristwatches.

The first watches with the new movement are the Reference 11L (lever escapement) and 11C (detent escapement), which maintain the appearance of the traditional Urban Jürgensen wristwatch. The References 11 will be cased in either platinum or rose gold and follows the typical company tradition of a hand engine-turned silver dial displaying hours, minutes, seconds and power reserve (ref. 11C).

Technical details
Movement
UJS P8
Diameter: 32 mm Height: 5.25 mm
Power source: Two barrels in series
Power reserve: 88h running time, indication by means of patented differential system
Balance: Freesprung, diameter 12.0 mm, moment of inertia 24 mg.cm2

Escapement
ref. 11C: pivoted detent escapement
ref. 11L: Swiss lever escapement

Case, Dial & Strap
Case: waterproof, saphire crystal back, platinum or 18 ct. rose gold, diameter 42 mm
Dial: Hand-engine turned silver dial, indication of hours, minutes and seconds, power reserve indication (88h)
Bracelet: leather, rose gold or platinum buckle

The chronometer escapement
The invention and development of the chronometer escapement, towards the end of the 18th century, was ascribed to John Arnold, Thomas Earnshaw, Pierre Le Roy and Ferdinand Berthoud. The new escapement proved to be a horological milestone that very quickly improved the precision of timekeepers. This characteristic was particularly decisive for navigation on the oceans of the world. The chronometer escapement delivers impulses directly to the balance from the escape wheel, without an intermediate component such as the lever in most modern watches. Each oscillation of the regulating organ, the balance and the spring, is only disturbed once, not twice as in other escapements. This arrangement is highly advantageous for the precision of the timekeeper. The escapement has a pivoted arm controlled by a fine spring. It is this detent which allows the escapement to be locked and unlocked as required.

Urban Jürgensen has succeeded for the first time to develop and put into practice a chronometer escapement that meets the highest requirements of reliability and resists the shocks to which a wristwatch is subjected.

UJS P8 Calibre
Introduced by Urban Jürgensen in 2012, the innovative self-winding caliber UJS P8 is the first automatic movement to ever integrate a pivoted detent escapement within a wristwatch.

This new automatic wristwatch based on in-house Caliber UJS P8 results from specific development research. The automatic winding is an integrated element specially developed for the caliber using the following special elements:

1. The very functional and reliable automatic module provides easy access for after-sales service and maintenance

2. The pivot and spring barrel bridge are intimately connected with each other.

3. The gold rotor mounted on a jewel bearing results in a simplified automatic system with little vulnerability

4. The unidirectional winding rotor and its ratchet wheel, which boasts an optimized tooth shape, is perfectly user-friendly and effective.

5. Five jewels in the bridge prevent the rotor being damaged even if it experiences great shock.

6. Rotor weight : 3,86 g

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