Watch movement comprising a retrograde display and a jump hour ring

1. A watch movement comprising:

a retrograde mobile;

an hours ring bearing an asymmetric internal toothing and driven via the retrograde mobile in order to display the current hour in a jumping way;

a correction mechanism allowing the retrograde mobile to be corrected in a bidirectional way;

a drive member that can be activated by said correction mechanism and engages with said asymmetric internal toothing so that corrections of the retrograde mobile in the clockwise direction are transmitted to the hours ring, and so that corrections in the counterclockwise direction are not transmitted to the hours ring.

2. The movement as claimed in claim 1 , in which said asymmetric internal toothing comprises a plurality of teeth with asymmetric flanks, said drive member being arranged in such a way as to be able to butt against one flank of a tooth of the internal toothing and to drive the hours ring when the retrograde mobile is rotating in the counterclockwise direction, and to slide along another flank of a tooth of the internal toothing when the retrograde mobile is rotating in the clockwise direction.

3. The movement as claimed in claim 1 , said retrograde mobile allowing the minutes to be displayed.

4. The movement as claimed in claim 3 , comprising a snail cam and a rack engaged with the snail cam in order to drive said retrograde mobile.

5. The movement as claimed in claim 4 , comprising a spring mounted on said rack and applying a force to press said drive member onto said asymmetric internal toothing.

6. The movement as claimed in claim 5 , in which the snail cam rotating in a first direction of rotation drives said rack and said retrograde mobile in the opposite direction of rotation.

7. The watch movement as claimed in claim 4 , in which said spring mounted on said rack comprises an end, for example a tooth-shaped end, designed to collaborate with said asymmetric internal toothing so as to control the counterclockwise rotation of the driving ring.

8. The watch movement as claimed in claim 7 , comprising a jumper having a shape designed to block any clockwise rotation of the drive ring when said jumper is engaged in a recess of an external toothing of the drive ring.

9. The watch movement as claimed in claim 8 , in which said jumper comprises an end substantially parallel to edge corners defining said recess when the jumper engages in said recess.

10. The movement as claimed in claim 3 , designed to allow unlimited correction of the hours and minutes display in the clockwise direction.

11. The watch movement as claimed in claim 3 , designed to allow correction of the minutes display in the counterclockwise direction.

12. The watch movement as claimed in claim 11 , comprising a correction blocking mechanism to prevent the minutes from being corrected in the counterclockwise direction within a range that includes the instant at which the retrograde mobile returns, and to allow the minutes to be corrected in the counterclockwise direction outside of that range.

13. The movement as claimed in claim 1 , in which the correction mechanism is designed to allow correction of the hours in the clockwise direction in a jumping way.

14. A method for correcting the display of an item of time-based information on a watch movement as claimed in claim 1 , in which, in a first interval:

the rotation of a time-setting stem in a first direction causes a snail cam to rotate in a first direction, and a rack to rotate in a second direction,

the rotation of the rack in a second direction causes a retrograde mobile and a drive member to rotate; and

said drive member moves along a first flank of an internal toothing of a ring without driving the rotation of said ring,

then, at minute 60:

the rotation of the snail cam causes the rack to fall and to rotate in the first direction near-instantaneously;

the near-instantaneous rotation of the rack in the first direction drives the near-instantaneous rotation of the retrograde mobile,

the rotation of said drive member pressing against a second flank of the internal toothing of the ring drives this ring with jumping and near-instantaneously.

15. The correction method as claimed in claim 14 , wherein:

the rotation of the time-setting stem drives the snail cam;

the rotation of the snail cam causes the rack to rotate in the opposite direction,

the rotation of the rack causes the retrograde mobile and the drive member to rotate.

16. The correction method as claimed in claim 15 , wherein the correction of the minutes display in the counterclockwise direction is limited to a range that excludes the instant at which the retrograde mobile returns.