This escapement comprises a balance wheel (3), an escape wheel (1), a detent rocker (4) having an arresting element (4a) and an elastic clearance element (4c), means for inserting the arresting element into the path of the teeth of the escape wheel (1), and a clearance pin (7) rotating integrally with the balance wheel (3) in order to engage with the elastic clearance element (4c) of the rocker (4) once per period of oscillation of the balance wheel. The means for inserting the arresting element (4a) into the path of the teeth of the escape wheel (1) comprise a sliding surface (4b) integral with the detent rocker (4) and arranged so as to move into the path of the teeth of the escape wheel (1) when the arresting element (4a) leaves it, this sliding surface being shaped so as to return the arresting element (4a) to the locking position.
Inventors: Alexandre Chiuve, Fabiano Colpo
Original Assignee: Rolex S.A.
Primary Examiner: Vit Miska
Attorney: Westerman, Hattori, Daniels & Adrian, LLP
Current U.S. Classification: 368/127; 368/129,
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Citations
Cited Patent Filing date Issue date Original Assignee Title) D3 F) S$ p- x x" h9 V
US40508 Nov 3, 1863 IMPROVEMENT IN TIME-KEEPERS
US51191 Nov 28, 1865 IMPROVEMENT IN CHRONOMETER-ESCAPEMENTS7
US1091261 Jul 22, 1913 Mar 24, 1914 CHRONOMETER-ESCAPEMENT
US3538705 Nov 7, 1968 Nov 10, 1970 ES CAPEMENT
US4122665 Jul 6, 1976 Oct 31, 1978 ETA A.G. Ebauches-Fabrik Method of manufacturing a pallet lever and pallet lever made by this method
US7097350 Mar 29, 2006 Aug 29, 2006 Montres Breguet SA Detent escapement for timepiece
Claims
1. Direct-impulse escapement, especially of detent type, for a horological movement, comprising:
a balance wheel attached to an impulse element,
an escape wheel whose teeth intersect the path of the impulse element,
a detent rocker having an arresting element and a clearance element,
means for inserting the arresting element into the path of the teeth of the escape wheel,
a clearance pin rotating integrally with the balance wheel, and
means for engaging said clearance pin (7,11d) with the clearance element of the rocker once per period of oscillation of the rocker to clear the arresting element from the escape wheel tooth;
said means for inserting the arresting element into the path of the teeth of the escape wheel comprising a sliding surface integral with the detent rocker and arranged so as to move into the path of the teeth of the escape wheel when the arresting element leaves it,
this sliding surface being shaped so that the force applied to it by a tooth of the escape wheel causes the arresting element of the detent rocker to move back into the path of the teeth of the escape wheel
the arresting element of the detent rocker comprising a safety surface situated outside of the path of the teeth of the escape wheel (1) and adjacent to this path when the detent rocker is in the unlocking position, in order to prevent the arresting element (4) from moving into the path of the teeth of the escape wheel while the latter is communicating a movement impulse to the balance wheel.
2. Escapement according to claim 1, in which the length of the safety surface corresponds to the angle travelled by the escape wheel to communicate the movement impulse to the balance wheel, in order to prevent the premature return of the arresting element into the path of the teeth of the escape wheel.
3. Escapement according to claim 1, in which said clearance element is pressed elastically against a stop, so that it behaves like a rigid element when said clearance pin meets it while rotating in one direction and moves away elastically when the disengagement pin meets it while rotating in the other direction.
4. Escapement according to claim 1, in which said clearance pin is integral with an inertial member mounted freely between two extreme positions, in one of which the path of the clearance pin passes by said clearance element of the rocker, and in the other of which this path does not pass by this clearance element, the passage of the inertial member from one position to the other resulting from the inertial force acting on the inertial member due to the variations of speed of the balance wheel during each half-cycle of oscillation of the balance wheel.
5. Escapement according to claim 2, in which said clearance element is pressed elastically against a stop, so that it behaves like a rigid element when said clearance pin meets it while rotating in one direction and moves away elastically when the disengagement pin meets it while rotating in the other direction.
6. Escapement according to claim 2, in which said clearance pin is integral with an inertial member mounted freely between two extreme positions, in one of which the path of the clearance pin passes by said clearance element of the rocker, and in the other of which this path does not pass by this clearance element, the passage of the inertial member from one position to the other resulting from the inertial force acting on the inertial member due to the variations of speed of the balance wheel during each half-cycle of oscillation of the balance wheel.