WINDING AND SETTING MECHANISM

When the crown is pulled out, the winding stem extends outwards by approximately 1 mm. During this movement, the stem drives the setting lever in a limited rotational motion. As it pivots, the setting lever pushes the yoke towards the centre of the movement. The end of the yoke carries with it the sliding pinion, which moves along its squared section towards the centre. The setting lever limits each mobile component’s displacement. As it approaches the centre, the epicycloidal toothing of the sliding pinion meshes with the first intermediate wheel. The crown can then be turned to set the time.

When the crown is pushed back in, the mechanism returns to its original position. The stem again actuates the setting lever, which now pivots in the opposite direction. Pressed against the inclined plane of the setting lever by its spring, the yoke pivots outward, carrying the sliding pinion with it until it disengages from the first intermediate wheel, and its Breguet toothing engages with the winding pinion. From this point, turning the crown drives the winding stem, which in turn drives the sliding pinion. When turned in one direction, the sliding pinion engages the winding pinion, the crown wheel, and finally the ratchet wheel. When turned in the opposite direction, the sliding pinion disengages from the winding pinion under the combined effect of its Breguet toothing and the yoke spring.

Until the 19th century, both winding and time-setting required a key. This key was used to drive either the barrel arbor (for winding) or the centre pinion (for time-setting), each of which had a square end corresponding to the key. In 1842, Adrien Philippe invented the keyless winding mechanism, operated by a crown. This innovation allowed the winding mechanism to be driven directly via a crown permanently connected to the movement and accessible from outside the case. The same crown could also be used for time-setting, though it still required an additional external control element (a small sliding lever on the case flank) to switch between the two functions, both actuated via the crown.

It was not until 1866 that Antoine LeCoultre developed the combined winding and setting mechanism with a setting lever (yoke), as we know it today. From that point on, simply pulling the crown engaged the time-setting mechanism, while pushing it back in re-engaged the winding train. Since then, the system has been refined and expanded to control numerous additional functions. The most common being date and day-of-the-week corrections, which can be adjusted through an intermediate crown position.