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the construction of the octa calibre has less powerful ties with the history of watchmaking than do the remontoir or the resonance models but it nonetheless symbolises an horological ideal of giving timekeepers the highest possible degree of precision and autonomy within this context one may mention jobst bürgi who used the remontoir to achieve three months of autonomy for his clock one might also note the fact that if church clocks are placed so high in addition to enhancing visibility it is mostly because it often took an entire month for the driving-weights to drop the full length of their cords many systems were invented to increase the duration of run of a watch meeting with various degrees of success given the small volume of a wristwatch the spring could not be as large as one might wish watchmakers therefore discovered the trick of placing an additional wheel inside the customary gear-train so as to extend the duration of its development unfortunately actually using this syste
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50
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octa réserve de marche bidirectional oscillating weight in 22-carat gold high-capacity barrel large-size chronometer balance rating inertia-blocks this movement provides steady and significant force thanks to a one-metre long spring supplying 850g of torque to the mechanism with only 25 loss of amplitude when its power-reserve is exhausted the watch will nonetheless continue to run for around thirty hours after the five days but without ensuring the same precision timekeeping moreover its fast winding mechanism designed to ensure high efficiency works in both directions on a classic simulator chappuis cyclo-test the mechanism is rewound in just one and a half hours such a performance should enable the wearer of the watch to maintain sufficient power-reserve merely through day-to-day gestures nonetheless prolonged periods of inactivity will lead to a depletion of the initial amount of energy this original and perfectly balanced construction by françois-paul journe has managed to attain
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55
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octa chronographe with the octa chronographe françois-paul journe is revolutionising the classical conception of a chronograph integrated within the octa automatic winding calibre measuring 30 mm in diameter and 5,7 mm in thickness the chronograph is housed in a space just 1 mm thick this space is also occupied by the concentric large date display discs to achieve such a performance françoispaul journe imagined flattening the usual column wheel to transform it into a cam wheel this means it is the profiled rim instead of the column which actions the chronograph levers a single sliding lever returns the chronograph seconds and minutes to zero by disengaging the brakes at the precise moment when it hits the specially profiled return-to-zero parts these two innovations make it possible to reduce the mechanism to three levels in this more compact version it gives rise to a sturdy movement ensuring long-term reliability it is fitted with fly-back and return-to-zero functions as well as a
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octa calendrier
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octa calendrier the annual calendar is the third complication to be integrated within the octa automatic winding calibre defined as the first automatic winding movement to ensure a minimum power-reserve of 120 hours five days enabling extremely precise time measurement even when not worn the originality of each of the octa complications is imposed by an identical mainplate for all models within the octa collection the mechanism must adapt to the milling and drilling required for other complications and must also be inserted within a thickness of just 1 millimetre once again françois-paul journe has achieved the feat of integrating within this five-day automatic calibre a complication as significant as an annual retrograde calendar while maintaining the dimensions of the mechanism at 30 mm in diameter and 5.7 mm thick the calendar which displays the day and month through two separate windows advances instantaneously and is self-adjusting for the months of 29 30 and 31 days the octa annu
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the annual calendar is driven by an internally geared large transmission wheel which surrounds the mechanism this activates the main lever every 24 hours the main lever reaches across the movement to advance the date-wheel and its hand day by day the date-wheel in turn drives the month wheel through a rack the days on a regular seven-day cycle are moved forward by the transmission wheel the automatic advance of the date from the end of short months to the beginning of the next month is programmed by a cam mounted on the month-wheel the five recesses around the cam s circumference representing the four months of 30 days and february act on the main lever that advances the date twice at the end of april june september and november the date-hand thus jumps from the 30th to the 1st as it climbs out of the recess for february which is deeper the main lever moves the date three times from february 29 to march 1 it is only at the end of a february with 28 days in three years out of four that
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