- Movement
- Manual winding
- Size
- 40 or 42 mm
Overview
Constant force, without oil
The F.P. Journe Chronomètre Optimum, reference CO, in 18K 6N gold, 5N gold and whitened guilloché silver dial, blued steel hands. 9.5 mm high; manually wound calibre 1510 in 18K rose gold: two barrels in parallel, a one-second remontoir, the oil-free EBHP bi-axial escapement and deadbeat seconds on the back.
The Chronomètre Optimum is the Classique collection's statement of chronometry: a hand-wound movement in 18K rose gold that brings together, in the brand's words for the first time in one watch, two barrels in parallel, a constant-force remontoir, natural deadbeat seconds and the escapement Journe calls the EBHP. By his own account he designed it in 2001 and it was the first watch in which he drove the deadbeat second from his one-second remontoir; he then set it aside while the Octa automatic calibres, the Sonnerie Souveraine, the Centigraphe Souverain and the Répétition Souveraine took his time, and in 2004, before it reached production, it inspired the Tourbillon Souverain with deadbeat seconds.
Journe states the design as three aims: less friction, a constant force at the escapement, and an escapement that runs without oil. The barrels in parallel remove the side load a single barrel puts on the great wheel and deliver a steadier force to the train. The remontoir at 11 o'clock, a light, balanced titanium device patented as EP 1 528 443 A1, rearms every second and holds the balance at the same amplitude for the first 45 hours of the 70-hour reserve, which matters because a hairspring, being imperfect, keeps its rate only while amplitude does not change. The EBHP, patented as EP11405210.3, is a direct-impulse escapement: its two escape wheels, on titanium arbors, give impulse to the balance staff directly, the principle of the eighteenth-century detent, Robin and Breguet natural escapements, which ran dry but were unsuited to a wrist. Journe's geometry starts by itself, and its ruby pallets lock the wheels at an angle that permits recoil, as in the Swiss lever, which isolates the locking anchor from the balance while the watch moves. On the dial the hours and minutes sit off-centre at 3 o'clock, small seconds at 9 and the reserve at 6, with the remontoir wheel in view; the deadbeat second is on the back.
For collectors
Two things about this watch are easy to misread. The deadbeat second is not on the dial: the small seconds at 9 o'clock advances six times a second at the escapement's rate, and the once-a-second step, tied to the remontoir, is the large hand read through the case back inside a seconds circle screwed to the bridges. And the amplitude the brand publishes is 260° at full wind and 260° after 24 hours, the same figure twice, which is what the constant-force remontoir is for.
Key details
Design and engineering
- Two barrels in parallelFitted for friction rather than reserve: in the brand's account, two barrels sharing the load remove the lateral pressure on the great wheel and exert a more even force on the train.
- One-second remontoirA constant-force device at 11 o'clock, in titanium so that it is light and balanced, rearmed once a second. The balance's amplitude is held constant for the first 45 hours of the reserve, since the hairspring keeps its rate only if amplitude does not change.
- EBHP escapementA bi-axial direct-impulse escapement with escape wheels and arbors in titanium, running without lubrication. Its geometry lets it self-start, and its ruby pallets lock with a recoil, in the manner of the Swiss lever, which keeps the locking anchor away from the balance during wrist movement. The brand cites Breguet's natural escapement as the inspiration.
- Natural deadbeat secondsThe large seconds hand on the back advances once a second because it is driven from the one-second remontoir, not by an added mechanism; the brand calls it natural for that reason.
- Dial and backOff-centre hours and minutes at 3 o'clock, small seconds at 9, reserve at 6, the remontoir wheel visible. Through the sapphire back, the deadbeat second inside a seconds circle screwed to the bridges. Blued steel hands.
- FinishingCircular graining on the base plate, Geneva waves on the bridges, polished screw heads with chamfered slots, pegs with polished rounded ends.
Calibre 1510
- Manual winding, 27 turns of the crown
- 18K rose gold
- Two barrels in parallel; one-second remontoir in titanium (EP 1 528 443 A1); EBHP bi-axial escapement in titanium, without oil (EP11405210.3)
- Free-sprung chronometric balance with inertia weights, hairspring with Phillips curve; 21,600 vibrations per hour (3 Hz), 44 jewels, angle of lift 58°
- Amplitude 260° dial-up at 0 h and at 24 h
- Power reserve 70 ± 2 hours, constant amplitude for the first 45 hours
- 34.00 mm overall diameter, 5.80 mm high, 240 parts (264 cased up with strap)
The reference
Technical specifications
| Reference | CO |
|---|---|
| Collection | Classique |
| Calibre | Calibre 1510 |
| Movement | Manual winding |
| Functions | Off centre hours and minutes at 3h00, Small second at 9h00, Power reserve at 6h00, Large dead beat second on the back |
| Case dimensions | 40 or 42 mm |
| Case thickness | 9.5 mm |
| Case material | 18K 6N Gold |
| Dial | 5N Gold and whitened guilloché Silver |
| Hands | blued Steel |
| Jewels | 44 |
| Power reserve | 70 ± 2 hours |
| Frequency | 21,600 Alt/h (3Hz) |
| Movement parts | 240 |
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