Patent ID: 7242640
Filing Date: 2007-07-10
Classification: G04B

Abstract:
1. An annual date mechanism for a timepiece movement comprising a 31-toothed date runner, a jumper in mesh with its toothset, a months satellite, the rotation pin of which is secured to this date runner and which comprises five driving teeth of a toothset on a pitch designed for twelve for the months comprising less than 31 days, a fixed planetary toothset coaxial with the date runner and in a direct-drive relationship with the months satellite and a drive member for driving the date runner in a driving relationship with the hours wheel of the timepiece movement and 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 when its axis of revolution is aligned with those of the planetary toothset, of the drive member and of the date runner, wherein the months satellite is connected to the planetary toothset by a second satellite which is secured to it and coaxial and the number of teeth of which is equal to a multiple of twelve, and the toothset of each of said satellites works on a pitch circle tangential to the pitch circle of the toothset with which it is in mesh, the number of teeth z i of the planetary toothset being chosen from numbers or multiples of numbers obtained according to the formula: so that each revolution of the date runner corresponds to a non-integer number of revolutions of the satellites such that one of the five teeth of the months satellite is more or less aligned with the axes of the satellites, of the planetary toothset and of the drive member driving the date runner on the 30th of each month comprising less than 31 days so as to allow said second finger to drive the date runner by an additional step via said satellites.