Patent ID: 7218576

Claim:
An annual calendar mechanism for a timepiece including a date disc to which thirty one figures are affixed each corresponding to an indication of a day of the month provided with a first inner toothing including thirty one teeth, a date drive wheel set, said wheel set including a finger driving the date disc through one step per day via one of the teeth of the first inner toothing in order to control the date display, said date disc including a second toothing, a correction drive wheel set able to cooperate with the second toothing to drive the date disc through an additional step at the end of the months of less than thirty one days, and a month star wheel arranged to be actuated at the end of each month and to complete one revolution per year, wherein this annual calendar mechanism includes a month drive wheel set provided for driving the month star wheel at the end of each month, said month drive wheel set being connected, via a gear train, to the date drive wheel set and to the additional correction drive wheel set, said month drive wheel set occupying a first position in which it has no effect on the month star wheel, such that the kinematic chain between the date disc and the month star wheel is broken, and a second position that it occupies only at the moment when the change of month occurs and in which it actuates the month star wheel so as to move it one step forward, such that a correction device can act on the date disc without any effect on the month star wheel and vice versa.