Mechanism for driving an indicator for a timepiece
A mechanism for driving an indicator for a timepiece includes: a mobile for driving the indicator; a first lever mounted about a first pivot and including a beak to cooperate with a toothing of the mobile; a first cam arranged to rotate the first lever about the first pivot; a second lever mounted about a second pivot and to which the first pivot is rigidly connected; a second cam arranged to rotate the second lever about the second pivot; and elastic elements for maintaining the cooperation between the levers and cams; the levers and the cams being arranged so that the beak of the first lever cyclically describes a closed curve, each cycle including a first motion during which the beak leaves the toothing of the mobile without changing the angular position thereof and a second motion during which the beak re-enters the toothing to move the mobile.
1. Mechanism for driving an indicator for a timepiece, comprising:
a mobile ( 22 ; 23 ) for driving the indicator,
a first lever ( 16 ) mounted about a first pivot ( 17 ) and comprising a beak ( 20 ; 21 ) intended to cooperate with a toothing of the mobile ( 22 ; 23 ) to move said mobile,
a first cam ( 2 ) arranged to rotate the first lever ( 16 ) about the first pivot ( 17 ),
a second lever ( 11 ) mounted about a second pivot ( 12 ) and to which the first pivot ( 17 ) is rigidly connected,
a second cam ( 3 ) arranged to rotate the second lever ( 11 ) about the second pivot ( 12 ), and
elastic means ( 10 , 13 ) for maintaining the cooperation between the levers ( 16 , 11 ) and the cams ( 2 , 3 ),
the levers ( 16 , 11 ) and the cams ( 2 , 3 ) being arranged so that the beak ( 20 ; 21 ) of the first lever ( 16 ) cyclically describes a closed curve, each cycle comprising a first motion during which the beak ( 20 ; 21 ) leaves the toothing of the mobile ( 22 ; 23 ) without changing the angular position of said mobile and a second motion during which the beak ( 20 ; 21 ) re-enters the toothing of the mobile ( 22 ; 23 ) to move said mobile.
2. Mechanism according to claim 1 , wherein the beak ( 20 , 21 ) is non-retractable.
3. Mechanism according to claim 2 , wherein the levers ( 16 , 11 ) and the cams ( 2 , 3 ) are arranged so that the mobile ( 22 ; 23 ) moves by instantaneous jumps.
4. Mechanism according to claim 2 , wherein the first and second cams ( 2 , 3 ) are coaxial.
5. Mechanism according to claim 2 , further comprising a third lever ( 8 ) mounted about a third pivot ( 9 ) and arranged so that the first lever ( 16 ) is driven by the first cam ( 2 ) via this third lever ( 8 ).
6. Mechanism according to claim 2 , further comprising a device ( 28 - 36 ; 39 - 42 ) to cause the beak ( 20 ; 21 ) to automatically leave the toothing of the mobile ( 22 ; 23 ) before a correction of the position of said mobile.
7. Mechanism according to claim 1 , wherein the levers ( 16 , 11 ) and the cams ( 2 , 3 ) are arranged so that the mobile ( 22 ; 23 ) moves by instantaneous jumps.
8. Mechanism according to claim 1 , wherein the first and second cams ( 2 , 3 ) are coaxial.
9. Mechanism according to claim 1 , further comprising a third lever ( 8 ) mounted about a third pivot ( 9 ) and arranged so that the first lever ( 16 ) is driven by the first cam ( 2 ) via this third lever ( 8 ).
10. Mechanism according to claim 1 , further comprising a device ( 28 - 36 ; 39 - 42 ) to cause the beak ( 20 ; 21 ) to automatically leave the toothing of the mobile ( 22 ; 23 ) before a correction of the position of said mobile.
11. Mechanism according to claim 10 , wherein said device ( 28 - 36 ) can be actuated by a displacement of a winding stem ( 27 ) into a predetermined axial position.
12. Mechanism according to claim 11 , wherein said device ( 28 - 36 ; 39 - 42 ) comprises means ( 35 , 36 ; 42 ) for moving the second lever ( 11 ) away from the second cam ( 3 ), this motion causing a displacement of the first lever ( 16 ) causing the beak ( 20 ; 21 ) to leave the toothing of the mobile ( 22 ; 23 ).
13. Mechanism according to claim 10 , wherein said device ( 28 - 36 ; 39 - 42 ) comprises means ( 35 , 36 ; 42 ) for moving the second lever ( 11 ) away from the second cam ( 3 ), this motion causing a displacement of the first lever ( 16 ) causing the beak ( 20 ; 21 ) to leave the toothing of the mobile ( 22 ; 23 ).
14. Calendar mechanism for a timepiece comprising a mechanism according to claim 1 .
15. Timepiece comprising a mechanism according to claim 1 .