BREGUET CLASSIQUE CHRONOMÉTRIE 7727
Over the past ten years Breguet has filed over 100 patents. Primarily concerning improved timekeeping and striking mechanisms. With its patent of November 9, 2010 for a magnetic pivot, harnessing magnetism to the service of precision and reliability.
The balance frequency of 10Hz compared to a more common frequency of 4Hz, (28,800 VPH) was applied for the first time in the Type XXII chronograph, this frequency was shown to have improved the time-keeping performance of the balance and spring.
Breguet’s use of silicon enables the Classique Chronométrie to be fitted with a double balance-spring, pallet lever and escape wheel, all in specially prepared silicon that reaches the high frequency necessary for optimum precision.
It is likely that the impact of this invention will not be felt for a few years yet but with the magnetic pivot, the watch not only controls the negative effects of magnetism, but also uses magnetic force to improve the pivoting, rotation and stability of the balance staff.
Breguet’s watchmakers designed a stable system using two endstones incorporating powerful micro-magnets (approx. 1.3 teslas) that keep the balance staff centred and self-adjusting.
One of the magnets is stronger than the other to create a magnetic gradient. A magnetic flux, generated within the balance-staff induces a magnetic attraction that keeps the end of the pivot in contact with the endstone.
Held in an artificial gravitational force, the balance staff is unaffected by the different positions of the watch and the conditions at each pivot remain unchanged. If a shock knocks the balance staff sideways, the system acts like a pare-chute to return it to its position, except that magnetic forces re-centre the staff to regain maximum magnetic flux.
The result is a balance that is insensitive to gravity, more stable and resistant to shocks. These innovations bring the reference 7727’s average rate to -1/+3 seconds a day, well within the COSC chronometer standard of -4/+6 seconds a day.
More importantly, the difference in rate between the six positions has been brought down to -2/+4 seconds a day (maximum wind). Six patents protect the technical innovations.
Hand-wound movement with stop seconds. Numbered and signed Breguet. Cal. 574DR, 14 lignes, 45 jewels. Power reserve of 60 hours with an indicator at 5 o'clock. Double barrel. In-line Swiss lever escapement in silicon. Double silicon balance-springs at 180°. 10Hz frequency. Magnetic pivots. Adjusted in six positions.
