ANNUAL CALENDAR MECHANISM FOR WATCH MOVEMENT

The invention concerns an annual calendar mechanism for a timepiece including a date disc ( 16 ) to which are thirty one figures are affixed each corresponding to an indication of a day of the month provided with a first inner toothing ( 20 ) including thirty one teeth ( 20 a), a date drive wheel set ( 32 ), said wheel set ( 32 ) including a finger ( 34 ) driving the date disc ( 16 ) through one step per day via one of the teeth ( 20 a) of the first inner toothing ( 20 ) in order to control the date display, said date disc ( 16 ) including a second toothing ( 24 ), a correction drive wheel set ( 42 ) able to cooperate with the second toothing ( 24 ) to drive the date disc ( 16 ) through an additional step at the end of the months of less than thirty one days, and a month star wheel ( 54 ) arranged to be actuated at the end of each month and to complete one revolution per year, characterized in that in includes a month drive wheel set ( 52 ) provided for driving the month star wheel ( 54 ) at the end of each month, said drive wheel set ( 52 ) being connected, via a gear train ( 35, 56 ), to the date drive wheel set ( 32 ) and to the additional correction drive wheel set ( 42 ), said wheel set ( 52 ) occupying a first position in which it has no effect on the month star wheel ( 54 ), such that the kinematic chain between the date disc ( 16 ) and the month star wheel ( 54 ) 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 ( 54 ) so as to move it one step forward, such that a correction device ( 90 ) can act on the date disc ( 16 ) without any effect on the month star wheel ( 54 ) and vice versa.