Calibre L044.1
SEEN THROUGH A WATCHMAKER’S LOUPE (4 MB)

THE MOVEMENT OF THE RICHARD LANGE "Pour le Mérite".

With no fewer than 915 individual parts, the calibre L044.1 movement is one of the most complex masterpieces in precision watchmaking. True to Lange’s quest for perfection, each one is hand-finished, for instance with Glashütte ribbing on the three-quarter plate or with traditional engravings whose patterns adorn the escape-wheel and fourth-wheel cock as well as the balance cock. Most of the parts have the sole purpose of enhancing the rate accuracy of the RICHARD LANGE “Pour le Mérite” – which of course is the key functional objective of a contemporary observation watch of superior quality.



The fusée-and-chain transmission
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THE FUSÉE-AND-CHAIN TRANSMISSION.

The most elaborate measure implemented to enhance precision of this timepiece is the fusée-and-chain transmission, a mechanism very rarely integrated in wristwatches. It equalises the varying magnitudes of torque delivered by the mainspring between the fully wound and fully unwound states, thus stabilising the rate of the watch. This is done by diverting the power from the mainspring barrel to an intricate 636-part chain rather than transmitting it directly to the going train.

The fusée-and-chain transmission is supplemented with three further mechanisms that optimise the efficiency of the power train: the pretensioning mechanism, the blockage mechanism before the fully wound state, and the blockage mechanism before the fully unwound state.

Blocking the movement before the maximum state of wind

BLOCKAGE BEFORE FULLY WOUND AND
FULLY UNWOUND STATES.

The mainspring of a mechanical watch does not deliver its energy to the going train in a uniform manner. Its output torque fluctuations are particularly significant in two states: right after it is fully wound and just before it is fully unwound. These two extremes are prevented by blocking the winder just before the maximum state of wind and by blocking the movement just before the movement is fully unwound. The time between these two states corresponds exactly to a power reserve of 36 hours.

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The pretensioning mechanism

THE PRETENSIONING MECHANISM.

The addition of the pretensioning mechanism allows the watchmaker to perfectly harmonise the characteristics of the mainspring and of
the fusée-and-chain transmission. In every individual watch, the use-ful torque range is identified and adjustments are made to match it with the fusée’s characteristic of the transmission. The rotation of the pre-tensioning ratchet wheel also turns the barrel arbor core seated on the same axis, thus relaxing or tensioning the mainspring attached to it.