A timepiece, particularly a wristwatch, comprising a retrograde date display presenting a graduation from 1 to 31 (2) on the dial (1) cooperating with a hand (3) driven by the mechanism which comprises a sleeve (4) comprising this hand and fast with a pinion (5) meshing with two racks (9) pivoted on a plate (6) of the movement acting in opposite direction on the pinion (5), one of said rack being submitted to the action of a return spring, whereas the free end of the other rack is maintained, by the force of said return spring, permanently against a snail cam carried by a date crown (11) pivoted on said plate (6) and driven in a known manner of one step each day by the watch movement.
This mechanism comprises a date runner, a months satellite with five teeth on a pitch for twelve, secured to the date runner, a fixed planetary toothset and a drive member for driving the date runner comprising two drive fingers, the first intersecting the path of the toothset of the date runner, the second intersecting the path of the toothset of the months satellite. The latter is connected to the planetary toothset by a second satellite secured to it and the number of teeth of which is equal to a multiple of twelve, the number of teeth of the planetary toothset being chosen so that one of the five teeth of the months satellite is aligned with the axes of the satellites, of the drive member and of the date runner on the 30th of each month comprising less than 31 days.
This timepiece comprises an annual or perpetual date display mechanism and also comprises means (11) for operating a device (13) for displaying the number of days in the month being displayed.
The invention relates to a timepiece comprising a time train, a 31-toothed wheel, a wheel of units of 30 teeth plus a space corresponding to a tooth which is used to drive a star-wheel of units and a four-toothed wheel for driving a star-wheel of tens, a year cam which is solidly connected to a wheel, and drive means for driving said 31-toothed wheel by one revolution per month and the year cam by one revolution per year. The aforementioned 31-toothed wheel is solidly connected to a corrector element. The drive means comprise a cam which is solidly connected to a wheel, a driving yoke, elastic means which are used to press said yoke against the cam, a corrector yoke, a feeler which is arranged to detect the position of the year cam and elastic means in order to connect said yokes to one another.
