JAEGER-LECOULTRE: DIVE: COLLECTION: THE PRODUCTS: MOVEMENTS

Jaeger-LeCoultre movements meet a fundamental requirement: the need to combine long-term performance and a high level of technical refinement.

The automatic movements powering the new Master Compressor Diving collection share in this same quest for sturdiness, reliability and accuracy.

Housed within rugged cases, they contribute to the assurance that each Master Compressor Diving watch will prove an ideal companion in even the most extreme sports.

Jaeger-LeCoultre Calibres 979, 975D and 971, each in its own way displaying a second time zone, along with Jaeger-LeCoultre Calibre 751D, offering the full range of chronograph functions, all incorporate the key characteristics of the latest generations of Jaeger-LeCoultre automatic movements.

Enjoy a detailed look at their exceptional performances in this section.

Rotor mounted on ceramic ball-bearings,
unidirectional winding

Since 2004, ceramics has replaced stainless steel for the ball bearings on the rotors of Jaeger-LeCoultre automatic calibres, offering the additional advantage of requiring no maintenance or lubrication.

This option thereby reduces the inevitable degradation of the mechanism due to thickening oils and the ensuing risk of clogging.

After lengthy trials, Jaeger-LeCoultre demonstrated that winding in both directions does not yield ideal performances when a watch is worn on the wrist.

Within this daily context, winding in one direction only provides enhanced energetic efficiency.

Spyr type wheel teeth

All the teeth on the wheels composing the latest
Jaeger-LeCoultre automatic movements are "spyr" shaped.

Their slightly rounded profile facilitates meshing and improves the regularity of torque transmission, resulting in performances further enhanced by thicker wheels that reinforce the sturdiness of the movements.

Variable inertia balance

So as to meet the demands of high precision, the heart of the movement is a large-sized balance with an inertia of 14 mg*cm2, beating at 4 Hertz, meaning 28,800 vibrations per hour.

Precision adjustment is performed by means of four inertia-blocks arranged around the outer rim of the balance, thus eliminating any need for an index.

The two ends of the balance-spring itself are laser-welded to the stud and collet, whereas the balance-spring stud-holder, and thus the adjustment of the dead point, is blocked by a screw.

Two catches prevent any distortion of the hairspring.

This complete set of characteristics prevents any modifications in the rate, even in the event of a violent impact.

As for the escapement, it displays the classic Jaeger-LeCoultre arrangement with its 20-toothed wheel.

Moreover, for Jaeger-LeCoultre Calibres 971D, 975D and 979, the balance-cock, traditionally fixed on just one side is transformed into a balance-bridge screwed to either side of the mainplate.

This configuration also ensures an exceptionally secure hold in case of impacts.

Sturdy movements

The calibres powering the Master Compressor Diving line belong to the generation of extremely robust movements that are built in sizes enabling them to prove their exceptional performances even when subjected to violent impacts.

Jaeger-LeCoultre Calibres 751D, 971D and 975D display a generous 5.70 mm thickness, and as much as 7.30 mm for Calibre 979 (because it incorporates the "geographic" dual time-zone complication).

Specific characteristics of the Jaeger-LeCoultre
Calibre 751 chronograph movement

For its automatic chronograph movement,
Jaeger-LeCoultre has opted for the complex column-wheel device, a distinctive ratchet wheel that coordinates all phases of operation of the chronograph function, thereby ensuring perfect synchronisation.

Activating the chronograph instantly starts the central seconds hand thanks to a vertical disc-based coupling-clutch device.

This solution offers the advantage of simultaneously guaranteeing remarkable rating accuracy and the exact measurement of time intervals.

The vertical coupling-clutch enables the chronograph seconds wheel to accurate and instantly couple with that of the standard seconds.

Moreover, this device reveals all its virtues in case of shocks, preventing any inopportune momentary stoppage of the chronograph operation, which would lead to a discrepancy in timekeeping.

Finally, the 65-hour power reserve, ensured by two barrels, guarantees a longer period during which the watch runs at an optimal level of precision.