DEVICE FOR ACTUATING IN ITS DROP A LARGE ROCKER FOR CONTROLLING THE DISPLAY OF AN INSTANTANEOUS DATE MECHANISM OF A TIMEPIECE HAVING A PERPETUAL OR SECULAR DATE MECHANISM

摘要

The device for actuating in its drop a large rocker for controlling the display of an instantaneous date mechanism of a timepiece having a perpetual or secular date mechanism comprises a device for setting the large rocker to an angular value that is a function of the number of days in a given month and causing it to drop once per day, this large rocker driving a date indicator one step per day from the first to the penultimate day of a month and by one, two, three or four steps at the end of a month, depending on whether this month has thirty-one, thirty, twenty-nine or twenty-eight days. This device comprises at least one first return spring (26) for returning the large rocker (2) in its drops, its end resting permanently on a pin (24) belonging to the large rocker and being fixed to a date plate (1) in such a position relative to this pin (24) and to the pivot arbor (3) of the large rocker, that the lever arm applying the force of this first return spring (26) to the large rocker decreases as a function of the angular setting travel of this large rocker and therefore of said first return spring (26).