EP2690508B1 - Horological hairspring - Google Patents

Description

Field of the invention

The invention relates to an anti-gallop hairspring comprising at least one strand wound between a first end and a second end and comprising at least two pairs of turns each consisting of a first turn and a second turn immediately adjacent comprising respectively stopping means and stopping means complementary staggered with each other, and defining together, for each of said couples, a respective maximum angular stroke, during a local coupling of said first turn and said second turn resulting from the cooperation abutting said stop means with said complementary stop means during acceleration in contraction or extension of said hairspring greater than set values, for limiting the number of active turns of said hairspring.

The invention also relates to a sprung balance-spring comprising at least one such spiral, and comprising a rocker pivoting about an axis and to which is fixed said first or second end of said spiral.

The invention also relates to a watch movement comprising at least one such sprung balance and a plate carrying a mounting stud of one end of said hairspring.

The invention also relates to a timepiece comprising at least one such movement, and / or at least one such sprung balance.

The invention relates to the field of watchmaking mechanisms, and more particularly watch regulators.

Background of the invention

In mechanical watches, regulating bodies, including the exhausts must meet several criteria called "security". One of the safety, the anti-gallop system, aims to prevent the angular extension of the balance beyond a normal angle of rotation.

The technical problem is to design a safety mechanism, including anti-gallop, making a limitation of the pivot angle of a rocker during excessive acceleration, especially during shocks, especially for a detent escapement. Such an anti-gallop mechanism must be able to act in both directions of pivoting of the balance, that is to say both in extension and contraction of the spiral.

One solution consists in modifying the spiral geometry by co-operating in abutment with consecutive coil lugs, so as to make certain turns inactive, and thus to modify the rigidity of the spiral and its response to the pulses. Such a mechanism is known, capable of limiting the angular travel of the balance in both directions of pivoting, by the document EP 2 434 353 A1 in the name of WATCHES BREGUET SA, which describes a spiral anti-gallop by the hooking between them of notches belonging to consecutive turns, as well in contraction as in extension of the spiral. The manouvre is effective, however the recovery of torque remains relatively abrupt.

The present invention aims to improve safety, by disturbing only very slightly the inertia of the balance, limiting its angular travel in both directions of rotation, and progressively performing torque recovery.

Summary of the invention

For this purpose, the invention relates to a clockwise anti-gallop hairspring comprising at least one strand wound between a first end and a second end and comprising at least two pairs of turns each consisting of a first turn and a second turn. immediately adjacent turn comprising respectively stopping means and complementary stopping means staggered with each other, and defining together, for each of said pairs, a respective maximum angular stroke, during a local coupling of said first turn and said second turn resulting from the cooperation abutting said stop means with said complementary stop means during acceleration in contraction or extension of said hairspring greater than set values, for limiting the number of active turns of said hairspring, characterized in that, in at least two of said pairs of turns, said respective stop means and complementary stop means are arranged in such a way that they define values of maximum angular stroke different, so as to gradually limit the amplitude of pivoting between said first and second ends of said hairspring during angular or radial accelerations of said hairspring greater than said set values, so as to cooperate in abutment said stop means and complementary stop means of one of said pairs before those of the other, and thus to gradually modify the resulting rigidity of said hairspring, by deactivation or subsequent reactivation of some of its turns.

The invention also relates to a sprung balance-spring comprising at least one such spiral, and comprising a balance pivoting about an axis and to which is fixed said first or second end of said spiral, characterized in that the pivoting amplitude said balance is less than 360 °.

The invention also relates to a watch movement comprising at least one such sprung balance and a plate carrying a mounting stud of one end of said hairspring.

The invention also relates to a timepiece comprising at least one such movement, and / or at least one such sprung balance.

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en vue en plan, un spiral anti-galop selon l'invention, destiné à osciller autour d'un axe de pivotement, et attaché par son extrémité extérieure à un piton, et par son extrémité inférieure à une virole fixée à un balancier ; ce spiral comporte des butées réparties en quinconce sur des spires voisines, qui interfèrent les unes avec les autres en cas de choc ou de dépassement d'amplitude, deux jeux de spires voisines entre elles sont ainsi équipées, mais avec des angles de limitation différents entre un premier jeu, plus interne, où l'angle est le plus grand, et un deuxième jeu, plus externe, où l'angle est plus petit ;
• la figure 2 représente un diagramme de couple en fonction de l'angle de rotation du spiral ;
• la figure 3 représente, sous forme d'un schéma-blocs, une pièce d'horlogerie, notamment une montre, comportant un mouvement lequel inclut un balancier-spiral comportant un spiral selon l'invention.

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, in which:

• the figure 1 represents schematically and in plan view, an anti-gallop hairspring according to the invention, intended to oscillate about a pivot axis, and attached by its outer end to a peak, and by its lower end to a ferrule attached to a pendulum; this spiral comprises abutments distributed in staggered rows on neighboring turns, which interfere with each other in case of shock or amplitude overshoot, two sets of adjacent turns are thus equipped, but with different angles of limitation between a first game, more internal, where the angle is the largest, and a second game, more external, where the angle is smaller;
• the figure 2 represents a torque diagram as a function of the rotation angle of the spiral;
• the figure 3 represents, in the form of a block diagram, a timepiece, in particular a watch, comprising a movement which includes a balance-hairspring comprising a hairspring according to the invention.

Detailed Description of the Preferred Embodiments

The invention relates to the field of watchmaking mechanisms, and more particularly watch regulators.

The present invention aims to improve the safety of any oscillating mechanism or energy storage, comprising a spiral spring, including a balance sprung mechanism.

The principle adopted is to modify the resulting rigidity of the spring when an incident occurs, under conditions of use which differ from normal walking, and particularly during strong acceleration or shock.

The modification of the rigidity of the hairspring may have other applications, and the present description, which relates to a preferred application of this invention to the anti-gallop system of an escapement mechanism, is in no way limiting.

The present invention, applied to a sprung balance, aims to limit the angle of rotation of the balance in mechanical watches to a given value, especially for amplitudes greater than 360 °. The limitation of the angular stroke is in both directions of rotation and this without modifying the inertia of the balance. The sprung balance is said free during its normal angular stroke (compared to the anti-gallop system) in that it does not cause any shock during the normal movement of the sprung balance.

The principle of the proposed system is based on a temporary modification of the spiral geometry. During the extension or contraction of the hairspring due to the rotation of the balance, a relative angular and radial movement between the turns occurs. Limit stops, consisting of two stops, as well as a locking arm race, are implanted on two consecutive turns of the spiral. For a given maximum angle of rotation, the stops are placed on the turns so as to limit this relative angular travel between two turns. When the stop, according to the direction of rotation, blocks the stroke of the locking arm, the spiral loses an active coil and its rigidity is thus modified. This stop system is therefore based on the relative angular displacement between two turns.

The distance between the stops and the locking arm may be unsymmetrical.

The system according to the invention therefore limits the number of active turns, according to the angle of rotation, and according to the movement of the turns of the spiral. The rigidity of the hairspring, depending on the angle of rotation, can therefore be modified momentarily, by adding, on at least one pair of turns and at most all the turns, of such a system of stops. The stiffness according to the amplitude of rotation can therefore be defined by the distribution and the number of stop system distributed on the spiral. The invention seeks to effect a progressive limitation of the rotation angle by progressive modification of the resulting rigidity of the spiral.

Several pairs of turns are, according to the invention, equipped as well. The spiral comprises staggered stops on neighboring turns, which interfere with each other in the event of shock or amplitude overshoot, at least two neighboring sets of turns are thus equipped, but with limiting angles. different between a first game, more internal, where the angle is the largest, and a second game, more external, where the angle is smaller.

In an advantageous but non-limiting embodiment, care is taken to balance the center of gravity of the spiral. The geometry, distribution, position and number of stops require a thorough design, and this document summarizes only the principle.

The manufacture of such a spiral is based on micro-manufacturing processes allowing great freedom of planar design. It is possible to make such a spiral in silicon technology. The present invention is not limited to this technology, "LIGA" processes and other micro-manufacturing processes commonly used for timepiece components, and in particular exhaust mechanisms, are usable.

Thus, the invention relates in particular to a clockwise anti-gallop hairspring 1 comprising at least one strand 2 wound between a first end 3 and a second end 4. This hairspring 1 comprises at least two pairs of turns 50. Each pair 50 is composed of a first turn 51 and a second turn 52 immediately adjacent respectively comprising stop means 11 and complementary stop means 12 staggered with each other.

These stop means 11 and complementary stop means 12 together define, for the torque 50 to which they belong, a maximum angular travel CA during a local coupling of the first turn 51 and the second turn 52. This local coupling results from the abutting cooperation of the stop means 11 with the complementary stop means 12 during acceleration in contraction or extension of the hairspring 1 greater than set values, or amplitude overshoot during the rotation of the this spiral 1, to limit the number of active turns of the spiral 1.

According to the invention, at least two of these pairs of turns 50 define different angular stroke CA values, so as to progressively limit the amplitude of pivoting between the first 3 and second 4 ends of the spiral, 1, when angular or radial accelerations of the hairspring 1 greater than said set values, so as to abut one of the couples 50 before the other, and thus gradually modify the resulting rigidity of the hairspring 1, by deactivating or reactivating successively some of its turns 5.

The curve of the figure 2 shows the variation of the torque as a function of the angle of rotation, we see the breaks in slope at the passage of each point corresponding to an abutment and coupling configuration, as explained below.

In the preferred variant, and not limited to, illustrated by the figures 1 and 3 . in each pair 50, the stop means 11, situated on one of the two turns of the pair 50, comprise two stop stops 13, 14, of interfering trajectory with at least one complementary stop stop 15, situated on the other of the two turns of the same pair 50, that comprise the complementary stop means 12. The interference at the extreme stop positions defines a range of limitation of the angular stroke CA of the first turn 51 relative to the second turn 52. This limitation makes it possible to temporarily limit the number of active turns of the spiral 1, when said at least one complementary stop stop 15 bears on one of these two stop stops 13, 14.

In a particular variant, visible on the figure 1 , in addition to the stop stops provided on two opposing turns of the same pair 50, a turn, for example the first turn 51 or the second turn 52, comprises at least one radial stop 6 limiting the radial displacement of the first turn 51 relative to the second turn 52. This particular coupling is based on the relative radial displacement between the turns. It is however limited to the contraction of the hairspring and therefore to a single direction of rotation of the balance.

In this same particular variant, advantageously at least one radial abutment 6 comprises a friction surface 61, which is arranged to cooperate with a complementary friction surface 62 that includes the second turn 52 or the first turn 51 respectively.

In yet another variant, combining the abutment stops of the torque 50 and the radial abutment 6, it is the stop means 11 or the complementary stop means 12 which comprise this at least one radial abutment 6.

The invention also relates to a balance-spring balance spring comprising at least one such spring 1, and having a rocker 7 pivoting about an axis D and to which is fixed the first 3 or second 4 end of the hairspring 1. Preferably , the pivoting amplitude of this balance 7 is less than 360 °.

The invention also relates to a watch movement 20 comprising such a spring balance 10, and a plate 8 carrying a pin 9 for fixing one of the ends 3, 4 of the spring 1.

The invention also relates to a timepiece 30 comprising at least one such movement 20, and / or at least one such spring balance 10.

The system has the advantage of limiting the travel of the balance in both directions of rotation. This limitation is made by modifying the rigidity of the hairspring. This modification of the rigidity can be adapted by the choice of the number and the distribution of the abutment surfaces incorporated in the spiral.

The inertia of the balance spring system is modified only by the modification of the spiral inertia. The anti-gallop system does not disturb the oscillations normal sprung balance, it influences its operation only when exceeding the amplitude of rotation.

Claims (8)

1. Anti-trip balance spring (1) for a timepiece comprising at least one strand (2) wound between a first end (2) and a second end (3) and comprising at least two pairs (50) of coils each formed of a first coil (51) and a second coil (52) immediately adjacent to each other, respectively comprising an stopping means (11) and a complementary stopping means (12), quincuncial staggered with respect to each other, and together defining, for each of said pairs (50), a respective maximum angular travel (CA) during the local coupling of said first coil (51) and said second coil (52) resulting from said stopping means (11) cooperating in abutment with said complementary stopping means (12) in the event of accelerations in the contraction or extension of said balance spring (1) which are greater than desired values, in order to limit the number of active coils of said balance spring (1), characterized in that, in at least two of said pairs (50) of coils, said respective stopping means (11) and complementary stopping means (12) are arranged so as to define different maximum angular travel values (CA), in order to gradually limit the amplitude of pivoting between said first end (3) and said second end (4) of said balance spring (1) during angular or radial accelerations of said balance spring (1) which are greater than said desired values, so as to cause said stopping means (11) and said complementary stopping means (12) of one of said pairs (50) to cooperate in abutment before those of said other pair, and thus to gradually modify the resulting rigidity of said balance spring (1) by successively deactivating or reactivating some of the coils (5) thereof.
2. Timepiece balance spring (1) according to the preceding claim, characterized in that, in each said pair (50), said stopping means (11) includes two limit stop members (13, 14) whose trajectory interferes with at least one complementary limit stop member (15) comprised in said complementary stopping means (12) to define an interval limiting said maximum angular travel (CA) of said first coil (51) with respect to said second coil (52), in order to limit the number of active coils of said balance spring (1) when said at least one complementary limit stop member (15) is abutting on one of said two limit stop members (13, 14).
3. Timepiece balance spring (1) according to the preceding claim, characterized in that said first coil (51) or respectively said second coil (52) includes at least one radial stop member (6) limiting the radial motion of said first coil (51) with respect to said second coil (52).
4. Timepiece balance spring (1) according to the preceding claim, characterized in that said at least one radial stop member (6) comprises a friction surface (61) arranged to cooperate with a complementary friction surface (62) comprised in said second coil (52) or respectively said first coil (51).
5. Timepiece balance spring (1) according to claim 3, characterized in that said stopping means (11) or said complementary stopping means (12) include said at least one radial stop member (6).
6. Timepiece sprung balance (10) comprising at least one balance spring (1) according to claim 1, and comprising a balance (7) which pivots about an axis (D) and to which said first (3) or second (4) end of said balance spring (1) is pinned up, characterized in that the amplitude of pivoting of said balance (7) is less than 360°.
7. Timepiece movement (20) comprising a said sprung balance (10) according to the preceding claim and a plate (8) carrying a balance spring stud (9) for pinning up one of the ends (3; 4) of said balance spring (1).
8. Timepiece (30) including at least one movement (20) according to the preceding claim, and/or at least one sprung balance (10) according to claim 6.

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