EP3206091B1 - Isochronous clock resonator - Google Patents

Description

Field of the invention

The invention relates to an isochronous clock oscillator mechanism of the tuning fork type, comprising a fixed support and a carrying beam of a plurality of primary resonators each comprising at least one mass carried by an elastic flexible blade constituting an elastic return means and which is arranged to work in bending and which is embedded in said cross.

The invention also relates to a watch movement comprising at least one such isochronous oscillator mechanism.

The invention also relates to a watch comprising at least one such movement.

The invention relates to the field of clock oscillator mechanisms and regulators, in particular for mechanical movements.

Background of the invention

In a classic mechanical watch, the friction of the air on the balance, the friction of the pivots in their bearings and the piton reactions, limit the quality factor of the resonator. We try to remove the friction of the pivots and the reactions of the embedding.

For a watch, the isochronism of the movement must be optimal in all positions in space, which implies the design of movements able to compensate for the effects of gravitation on their constituents.

Older documents describe oscillators comprising a plurality of primary resonators having flexible branches, arranged relative to each other so as to average their errors.

A first type of oscillator with coupled primary resonators is known as a tuning fork whose each branch is formed by a primary resonator; however, such a system is very sensitive to variations in position in space.

The patent CH 451021 in the name of Ebauches SA thus describes a symmetrical oscillator U whose two flexible branches vibrate in tuning fork mode, each being connected to a rigid arm forming a counterweight, and each primary resonator thus formed is arranged so that the instantaneous center of rotation coincides with the center of gravity, so that the frequency of the oscillator does not hardly changes when changes in position in the center of gravity. The transition to a U-shaped architecture with extended branches is better than the U-shape of the prior art. However, the instantaneous center of rotation constantly moves during the oscillation of each primary resonator.

The patent CH 46203 also in the name of Ebauches SA is a variant of the above, comprising a counting device transforming the oscillating movements of one of the two resonators into rotating movements of a counting wheel, this counting device being attached to one of these arms rigid, so that the counting device is insensitive to accelerations and in particular to shocks.

The patent GB 1293159 in the name of SEIKO develops a theory based on the influence on the regularity of the derivative of the displacement of the center of mass with respect to the angle of rotation, and seeks a displacement along a straight line of the center of mass of each primary resonator , to optimize the influence on the market. For this purpose, the center of mass is positioned two-thirds of the bending blade used in this system, to theoretically cancel the effect on walking in the vertical positions. However the center of mass moves a lot, and such a system remains sensitive to shocks. Moreover, this theory is based on a geometrical approximation, because in reality the deformation of the flexible blade is no longer really an arc of a circle, and the presumably rectilinear displacement of the center of mass is not verified.

The document EP2365403A2 in the name of TIANJIN SEA GULL describes an oscillator system for a mechanical timepiece, comprising at least one balance free to rotate about an axis; and at least one spiral connecting this pendulum to a fixed point or to another pendulum. This spiral comprises a first turn connected to the first balance, and a second turn connected to the fixed point or the second balance, and a transition section connecting the first turn to the second turn, in which an approximately linear return torque for the first balance. is mainly provided by elastic deformation of the transition section and the two turns, to generate an oscillatory movement for at least the first balance.

The document CH435122A in the name of LONGINES describes a tuning fork with at least two branches, intended to be used as an oscillator of a timepiece, these branches are wound, including two spirally wound springs, located in parallel planes and intended to vibrate in phase opposition in a direction perpendicular to the planes of the springs.

Summary of the invention

The invention proposes to jointly solve the problem of isochronism and that of obtaining the best possible quality factor. It is, in a way, to combine the respective advantages of known mechanisms using as resonator, or a balance-spiral assembly relatively insensitive to differences in position in space in its developments and most advanced montages but whose quality factor is strongly limited by the pivoting and the different losses, or a tuning fork with parallel blades which, freeing from the pivoting, has a quality factor better than a balance-spring but is very sensitive to the position in the space.

To this end, the invention relates to an isochronous pendulum clock oscillator mechanism according to claim 1.

The invention also relates to a watch movement comprising at least one such isochronous oscillator mechanism.

The invention also relates to a watch comprising at least one such movement.

Brief description of the drawings

• la figure 1 représente, de façon schématisée et en vue en plan, un mécanisme oscillateur isochrone d'horlogerie, de type diapason, comportant un support fixe qui porte, par une liaison élastique principale, une traverse porteuse de deux résonateurs primaires plans, symétriques par rapport à un plan de symétrie, et comportant chacun une masse portée par une lame flexible élastique agencée pour travailler en flexion et encastrée dans la traverse ;
• la figure 2 simule, de façon schématisée :
  • ∘ l'influence de la gravité sur une première masse suspendue vers le haut par l'intermédiaire d'une lame flexible, et le diagramme de marche correspondant à un retard d'une certaine valeur,
  • ∘ l'influence de la gravité sur une deuxième masse identique suspendue vers le bas par l'intermédiaire d'une lame flexible identique, et le diagramme de marche correspondant à une avance d'une certaine valeur,
  • ∘ l'influence de la gravité sur un mécanisme selon l'invention qui combine les deux précédents, et le diagramme de marche correspondant à un défaut quasiment nul ;
• la figure 3 représente, de façon schématisée et en vue en plan, un premier mode de réalisation de diapason, dit « diapason en H » dans une version simplifiée ;
• la figure 4 représente, de façon schématisée et en perspective, une variante plus élaborée de diapason en H, représentée en figure 5 en éclaté ;
• la figure 6 illustre en éclaté, et avec un détail local, un diapason en H dans une configuration voisine de celle des figures 4 et 5, sans axes, et les figures 7A à 7H représentent les composants et l'assemblage de ce diapason en H de la figure 6 ;
• les figures 8 et 9 représentent, de façon schématisée et en vue en plan, un deuxième mode de réalisation de diapason, selon l'invention, dit « diapason en cornes de bouc » dans des versions simplifiées ;
• la figure 10 représente, de façon schématisée et en perspective, et avec un détail local, une variante plus élaborée de diapason en cornes de bouc ;
• la figure 11 illustre en éclaté un diapason en cornes de bouc dans une configuration voisine de celle de la figure 10, sans axes, et les figures 12A à 12H représentent les composants et l'assemblage de ce diapason en H de la figure 11 ;
• les figures 13 et 14 représentent, en perspective et en vue en plan, un diapason de torsion qui comporte des bras, chacun muni d'une masse à son extrémité distale, et oscillant dans des plans parallèles et de façon symétrique par rapport à un axe parallèle à ces deux plans ;
• la figure 15 illustre une autre variante de diapason avec deux résonateurs, chacun comportant un ressort-spiral encastré à une première extrémité sur une traverse commune et comportant une masse à une deuxième extrémité distale, ces deux résonateurs s'étendant selon deux plans parallèles et étant, en projection sur l'un de ces plans, symétrique par rapport à un plan de symétrie lequel est perpendiculaire à ces deux plans ;
• la figure 16 représente, de façon schématisée et en vue en plan, un mécanisme voisin du diapason en cornes de bouc de la figure 8, qui comporte, à chaque extrémité de la traverse, une paire de spiraux tous deux liés à la même masse respective au niveau de leur spire interne, et attachés à la traverse respective de part et d'autre de cette masse ;
• les figures 17 et 18 sont des croquis illustrant des surfaces coopérant en frottement en cas de dérive, ce frottement augmentant avec l'amplitude dans le cas de la figure 18 ;
• la figure 19 représente, de façon schématisée et en perspective, et avec un détail local, une variante où la traverse constitue un cadre entourant les résonateurs primaires, dans un exemple d'application à quatre résonateurs ;
• la figure 20 représente, de façon schématisée et en plan, une autre variante de traverse formée par un cadre, dans un oscillateur à lames droites, constituant le pendant du diapason en H ;
• la figure 21 représente, de façon schématisée et en plan, une autre variante de traverse formée par un cadre, dans un oscillateur à spiraux selon l'invention, constituant le pendant du diapason en cornes de bouc ;
• la figure 22 est un schéma-blocs représentant une montre comportant un mouvement incorporant un mécanisme oscillateur isochrone 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 is schematically and in plan view, an isochronous clock oscillator mechanism, of tuning fork type, comprising a fixed support which carries, by a main elastic connection, a carrier cross-section of two planar primary resonators, symmetrical with respect to a plane of symmetry, and each having a mass carried by an elastic flexible blade arranged to work in bending and embedded in the cross;
• the figure 2 simulates, schematically:
  • ∘ the influence of gravity on a first mass suspended upwards by means of a flexible blade, and the gait diagram corresponding to a delay of a certain value,
  • ∘ the influence of gravity on a second identical mass suspended downwards by means of an identical flexible blade, and the gait diagram corresponding to an advance of a certain value,
  • The influence of gravity on a mechanism according to the invention which combines the two preceding ones, and the gait diagram corresponding to a virtually zero defect;
• the figure 3 shows schematically and in plan view, a first embodiment of tuning fork, called "tuning fork H" in a simplified version;
• the figure 4 represents, schematically and in perspective, a more elaborate variant of H tuning fork, represented in figure 5 exploded;
• the figure 6 illustrates in exploded, and with a local detail, a tuning fork in H in a configuration close to that of figures 4 and 5 , without axes, and the Figures 7A to 7H represent the components and assembly of this tuning fork in H of the figure 6 ;
• the Figures 8 and 9 show schematically and in plan view, a second embodiment of tuning fork, according to the invention, called "tuning fork horns" in simplified versions;
• the figure 10 represents, schematically and in perspective, and with a local detail, a more elaborate variant of goat horn tuning fork;
• the figure 11 illustrates a burst of goat horn in a configuration similar to that of the figure 10 , without axes, and the Figures 12A to 12H represent the components and assembly of this tuning fork in H of the figure 11 ;
• the Figures 13 and 14 represent, in perspective and in plan view, a torsion tuning fork which comprises arms, each provided with a mass at its distal end, and oscillating in parallel planes and symmetrically with respect to an axis parallel to these two planes ;
• the figure 15 illustrates another variant of tuning fork with two resonators, each comprising a spiral spring recessed at a first end on a common web and having a mass at a second distal end, these two resonators extending in two parallel planes and being, in projection on one of these planes, symmetrical with respect to a plane of symmetry which is perpendicular to these two planes;
• the figure 16 represents schematically and in plan view, a mechanism close to the tuning fork horns of the goat horn figure 8 , which comprises, at each end of the crossbar, a pair of spirals, both of which are connected to the same respective mass at their inner turn, and attached to the respective cross-piece on either side of this mass;
• the Figures 17 and 18 are sketches illustrating surfaces cooperating in friction in case of drift, this friction increasing with the amplitude in the case of the figure 18 ;
• the figure 19 represents, schematically and in perspective, and with a local detail, a variant where the cross member constitutes a frame surrounding the primary resonators, in an example of application to four resonators;
• the figure 20 represents, schematically and in plan, another variant of cross-member formed by a frame, in a straight-blade oscillator constituting the counterpart of the H-tuning fork;
• the figure 21 is schematically and in plan, another variant of cross-member formed by a frame, in a spiral oscillator according to the invention, constituting the pendulum tuning fork goat horns;
• the figure 22 is a block diagram showing a watch having a movement incorporating an isochronous oscillator mechanism according to the invention.

Detailed Description of the Preferred Embodiments

The invention proposes to realize a resonator mechanism with the least possible loss, and that is the sensitive month chronologically to its orientation in the gravitational field.

The invention seeks to reduce losses, in particular due to friction of pivots, and displacements of the recess.

The inventive step is to remove the traditional pivots, while minimizing the movements of the center of mass and the reactions of the support.

A mechanical resonator necessarily comprises at least one elastic element and an inertial element.

It is advantageous then to use an elastic element to provide the guiding function. This elastic element is then advantageously higher, thicker, and stiffer than a conventional elastic element, which leads to favor the use of flexible blades.

It is advantageous to use rotary resonators whose center of mass coincides with the center of rotation, which reduces the influence of gravity and shocks in translation on the accuracy of the resonator.

The search for a high quality factor encourages the use of a tuning fork structure.

However, the losses must be minimized: indeed, when a flexible blade resonator operates, the quality factor is good during the reciprocating movement, but the reaction torque to the embedding results in losses.

Also, the inventive step consists in producing a tuning fork isochronous resonator, with a plurality of primary resonators arranged in a symmetry geometry with respect to an axis, and together constituting a tuning fork.

The invention is more particularly described below, in a nonlimiting manner, in the preferred form of a tuning fork with two primary resonators symmetrical with respect to a plane of symmetry, which constitutes a particular advantageous case because of its simplicity. However, the invention is applicable to any number of resonators: three, four, or more, provided that the symmetry of their relative arrangement and their relative temporal phase shift make it possible to compensate for the effects of the reaction torques on the embedding.

The assembly of these primary resonators is performed in such a way that they have at least one identical resonance mode, and that the resultant of the forces and torques at the embedding is zero.

Thus, the invention relates to an equilibrium tuning clock-type isochronous oscillator mechanism 1 comprising a fixed support 2 and a crossbar 4 carrying a plurality of primary resonators 10.

The primary resonators 10 constitute the equivalent of the arms that comprises a conventional fork fork, and crosses 4 the equivalent of the common part of the tuning fork which these arms.

Each primary resonator 10 each comprises at least one mass 5 carried by an elastic flexible blade 6 arranged to work in bending and embedded in the crossbar 4.

These primary resonators 10 have at least one identical resonance mode, they are arranged to vibrate in a phase shift between them of the value 2π / n, where n is their number, and are arranged according to a symmetry in space such that the resulting from the forces and torques applied by the primary resonators 10 on the crossbar 4 is zero.

The Figures 1 to 17 illustrate examples with two primary resonators, the figure 19 illustrates an example with four primary resonators.

According to the invention, this crossbar 4 is fixed to the fixed support 2 by a main elastic connection 3, the rigidity of which is greater than the rigidity of each elastic flexible blade 6. This characteristic ensures a coupling between the primary resonators 10.

In a particular advantageous embodiment, the rigidity of the main elastic connection 3 is greater than the total of the rigidities of all the flexible flexible strips 6 that comprise the primary resonators 10.

Advantageously, the damping of the main elastic connection 3 is greater than the damping of each elastic flexible blade 6, and, more particularly, the damping of the main elastic connection 3 is greater than the total of the damping of all the blades. elastic hoses 6 that comprise the primary resonators 10.

The primary resonators 10 are arranged in space so that the resultant of their operating errors due to gravitation is zero.

Preferably, the primary resonators 10 are rotatable, which makes the isochronous oscillator mechanism 1 according to the invention insensitive to gravitation.

Thus, each primary resonator 10 forms a rotary resonator, whose center of mass is on the place whose translations are minimal during rotation. This is to minimize movements of the center of mass in the gravity field or under the effect of shocks, and thus improve the chronometry of the system.

This main elastic connection 3 is preferably constituted by an elastic blade, it does not move substantially when the isochronous oscillator mechanism 1 oscillates in tuning fork mode. Indeed, the branches of the tuning fork constituted by the primary resonators 10 exchange energy movement through the cross 4, but the movements of the cross 4 are minimal.

The direction in which the centers of mass CM of the primary resonators 10 are moving is called the longitudinal direction X. One direction transverse Y is substantially perpendicular to this longitudinal direction X. A Z direction completes the direct trihedron.

In the variants illustrated in Figures 1 to 17 , crossbar 4 is straight and extends in the longitudinal direction X.

In an advantageous embodiment, but not limiting, which corresponds to the variants illustrated in the figures, all or part of the isochronous oscillator mechanism 1 is arranged symmetrically with respect to a plane of symmetry PS which extends parallel to the transverse direction Y.

The main elastic connection 3 extends between the cross member 4 and the fixed support 2. Preferably, but not necessarily, this main elastic connection 3 extends along the main direction Y, as can be seen in the examples of the figures.

Preferably, the primary direction which connects the point of embedding on the crosspiece 4 of an elastic flexible blade 6 to the center of mass CM of the corresponding primary resonator 10, when the latter is at rest is parallel to the longitudinal direction X.

The figure 1 illustrates a simplified embodiment of an isochronous clock oscillator mechanism 1 tuning fork type, comprising a fixed support 2 which carries, by a main elastic connection 3, made in the form of a flexible blade, a cross member 4 carrying two primary resonators planes 10A, 10B, symmetrical with respect to a plane of symmetry PS, and each comprising a mass, respectively 5A, 5B, carried by an elastic flexible blade, respectively 6A, 6B, arranged to work in bending and embedded in the crossbar 4, symmetrically with respect to the plane of symmetry PS.

The choice of a geometric symmetry of construction facilitates the development. However, such an isochronous oscillator mechanism 1 can also be realized with non-symmetrical primary resonators, and operate correctly.

In the variants illustrated by the figures 1 , 3 , 6 , 8 to 11 , Non-limiting, the primary directions of the different primary resonators 10 which constitute this isochronous oscillator mechanism 1 are parallel to the longitudinal direction X, or merged.

For maximum efficiency, the resilient flexible blades 6 are arranged so that the displacement of each center of mass CM of the given primary resonator 10 is minimal in the transverse direction Y where compensation is not provided, and so that the movements of the different centers of mass CM of the primary resonators 10 given are compensated with respect to each other in the longitudinal direction X: if, as in the case of the figures, the isochronous oscillator mechanism 1 comprises two primary resonators 10A and 10B arranged back to back from and other of the crossbar 4, their respective centers of mass CMA and CMB move essentially in the longitudinal direction X, but with displacements of the same value but in opposite directions.

The advantage of an arrangement according to the invention is to have elastic blades working in almost pure bending, which makes it possible to obtain an isochronous resonator. The torque is proportional to the angle α whose corresponding mass pivots. The frequency is therefore independent of the amplitude of the oscillation.

Preferably, the distance between the embedding of the resilient flexible blade 6 in the crossbar 4 and the center of mass CM is equal to the distance between the center of mass CM and the embedding of the elastic flexible blade 6 in the associated mass 5, as visible on the figure 1 . The center of mass CM thus remains on the X axis, or in the immediate vicinity of the X axis, that is to say at a distance of a few micrometers.

In a particular embodiment, which allows economical manufacture, in particular by the use of micro-machinable materials according to the "MEMS," LIGA "or similar methods, each primary resonator 10 is arranged to oscillate in a plane.

In a particular embodiment, each primary resonator 10 is monolithic.

In a particular embodiment, the cross member 4 and the flexible flexible blades 6 of the primary resonators 10 form a monolithic assembly.

In a particular embodiment, the fixed support 2, the main elastic connection 3, the crosspiece 4, and the flexible flexible blades 6 of the primary resonators 10, form a monolithic assembly.

In a particular embodiment, the fixed support 2, the main elastic connection 3, the crosspiece 4, and the flexible flexible blades 6 of the primary resonators 10, form a monolithic assembly.

Such an embodiment makes it possible to obtain elastic blades 6 called "high leaf", which have a height very large relative to their thickness, in particular at least five times higher than thick, and more particularly to less than ten times higher than thick. Such blades in high sheet make it possible to ensure the guiding function, and to overcome traditional pivots, which allows a significant increase in the quality factor.

The architecture in the form of a tuning fork, according to the invention, makes it possible to compensate for all the reactions to the recesses, which still considerably increases the quality factor.

In the embodiments illustrated in the figures, the masses 5, 51, 52, primary resonators 10 are essentially subjected to a pivoting movement. The corresponding resilient flexible blade 6 provides the pivotal guiding function.

The invention is illustrated here in variants where, each time, a single elastic flexible blade 6 maintains the respective mass 5 with respect to the crossbar 4. It is possible to imagine other variants where these blades 6 would be doubled or multiplied to ensure even better guidance. However the advantage of the single blade is to work in pure bending, which eliminates shear stresses, or transverse forces, which are unfavorable for isochronism, which explains the preference for a single flexible blade 6, which ensures therefore a better chronometry of a watch incorporating an oscillator 1 according to the invention.

In the case of variants, as illustrated by the figures, wherein each primary resonator 10 is arranged to oscillate in a plane, all the primary resonators 10 are arranged to oscillate in planes parallel to each other, or in the same plane.

More particularly, all these primary resonators 10 are arranged to oscillate in the same plane, for example on the embodiments illustrated in FIGS. Figures 1 to 12 .

In particular achievements, as visible on the Figures 13 to 16 these primary resonators 10 each extend in a separate plane.

It is nonetheless possible to implement the invention with primary resonators arranged differently in space.

The Figures 1 to 12 illustrate an isochronous oscillator mechanism 1, all primary resonators 10 are identical, even in number, and arranged in symmetry with respect to a plane of symmetry PS extending parallel to a transverse direction Y which is that of the main elastic link 3 and perpendicularly to a longitudinal direction X in which the centers of mass CM of the primary resonators 10 are movable.

Within each pair, the primary resonators 10 then oscillate in phase opposition, which guarantees the compensation of the movements of the centers of mass CM in the longitudinal direction X.

Preferably, the main elastic connection 3 is straight.

On variants of Figures 1 to 7 according to a first embodiment detailed below, the resilient flexible blades 6 are straight in the longitudinal direction X. The centers of mass CM of the primary resonators 10 considered are in their alignment at rest. This arrangement guarantees the insensitivity to the positions of the isochronous oscillator mechanism 1, unlike a tuning fork of the conventional type with parallel branches which is much too sensitive to the positions in space if it is incorporated in a watch, and which can only be suitable for 'to a pendulum piece.

• sur le croquis supérieur, sur une première masse suspendue vers le haut par l'intermédiaire d'une lame flexible, le diagramme de marche montre un retard d'une certaine valeur R,
• sur le croquis médian, sur une deuxième masse identique suspendue vers le bas par l'intermédiaire d'une lame flexible identique, et le diagramme de marche correspondant à une avance de la même valeur R,
• sur le croquis inférieur, sur un mécanisme qui combine les deux précédents, et le diagramme de marche correspondant qui montre une avance ou un retard proche de zéro, grâce à l'alignement en sens contraire, ce qui permet un équilibrage, par le moyennage des avance/retard des deux résonateurs qui le composent, rendant ainsi le mécanisme insensible aux positions dans l'espace.

The sketches of the figure 2 to understand the influence of gravity g :

• on the upper sketch, on a first mass suspended upwards by means of a flexible blade, the gait diagram shows a delay of a certain value R,
• on the median sketch, on a second identical mass suspended downwards by means of an identical flexible blade, and the gait diagram corresponding to an advance of the same value R,
• on the lower sketch, on a mechanism that combines the two previous ones, and the corresponding step diagram which shows a lead or a delay close to zero, thanks to the alignment in opposite directions, which allows a balancing, by the averaging of advance / delay of the two resonators that compose it, thus making the mechanism insensitive to positions in space.

The residual defect after compensation of the displacements of the centers of mass in X is of very small value, of the same order of magnitude as the defect due to displacements of the centers of mass in Y, which is limited to 3 or 4 micrometers, for a blade of 1 mm long, the cumulative defect thus remains less than 6 seconds per day.

The compensation due to the geometry of the isochronous oscillator mechanism 1 according to the invention, in particular in a fully symmetrical execution, reinforces therefore the character of insensitivity to gravitation due to the rotary operation of the primary resonators 10. The symmetry thus compensates for any residual error of operation.

In addition, the compensation of forces and torques to the recess allows the primary resonators 10 to oscillate very long without amortizing.

In a particular variant of this first embodiment, the resilient flexible blades 6 that comprise the primary resonators 10 are straight and aligned in pairs.

On the variants specific to the invention of Figures 8 to 12 , according to a second embodiment detailed below, the elastic flexible blades 6 are spiral wound around the centers of mass CM primary resonators 10 considered.

An illustrated variant on Figures 13 and 14 represents a torsion tuning fork which comprises arms 51 and 52, each provided with a mass at its distal end, and oscillating in parallel planes P1 and P2 and symmetrically with respect to an axis A parallel to these two planes P1 and P2.

Another variation of tuning fork illustrated by the figure 15 comprises two resonators, each comprising a spiral spring recessed at a first end on a common cross-member and having a mass at a second distal end, these two resonators extending in two parallel planes and being, in projection on one of these planes, symmetrical with respect to a plane of symmetry PS which is perpendicular to these two planes. The resulting torque is zero at the embedding at the crossbar 4.

It is understood that the invention allows a wide variety of geometric architectures.

The practical difficulties are not lacking, because it is difficult to ensure the limitation in displacement of the centers of mass CM of the primary resonators 10 in the transverse direction Y.

In addition, the mechanisms must be usable in a watch, and incorporate security, including shockproof.

Two particular embodiments, geometrically quite different, are presented below: a first tuning fork mode "in H", and a second mode obeying the logic of the invention, called tuning fork "goat horns".

The first tuning fork mode in H, is represented on the Figures 1 to 7 . The fixed support 2, the main elastic connection 3, the crosspiece 4, and the flexible flexible blades 6 of the primary resonators 10, together form a planar monolithic structure, made of silicon, or oxidized silicon, or quartz, or DLC, or the like, which , in the rest position of the isochronous oscillator mechanism 1, is symmetrical with respect to a plane of symmetry PS, and comprises an elongate cross member 4 which extends in the longitudinal direction X, perpendicular to the main elastic connection 3, which extends in the transverse direction Y, and which maintains the crossbar 4 on the fixed support 2.

This crosspiece 4 carries a pair of marked masses 51 and 52, mounted symmetrically on either side of the fixed support 2 and the first elastic connection 3.

These masses 51, 52, extend substantially in the transverse direction Y, forming the lateral bars of an H whose crossbar 4 constitutes the horizontal bar. Preferably each of them comprises an arm connected in its middle to the corresponding flexible blade 6, this arm extending substantially parallel in the transverse direction Y, and being either a solid arm as on the figure 3 , either an arm with inertial flyweights at its opposite ends, or substantially punctual as on the figure 1 , in the form of annular sectors, as visible on the figures 2 , and 4 to 7 .

Each of these masses 51, 52 is mounted oscillating about a virtual pivoting axis of position determined relative to the crossbar 4, and recalled by an elastic flexible blade 6, respectively marked 61, 62, which constitutes means of resilient return and which is secured to one end 41, 42 of the cross member 4, the two ends 41 and 42 being opposite and on either side of the crossbar 4. These flexible blades 61, 62, extend from preferably linearly in the extension and on both sides of the crossbar 4.

Each virtual pivoting axis is, in the rest position of the isochronous oscillator mechanism 1, coinciding with the center of mass CM1, CM2, of the respective mass 51, 52.

These resilient flexible blades 61, 62, are arranged to limit the displacement of the centers of mass CM1, CM2, to a transverse stroke relative to the crossbar 4, as small as possible in the transverse direction Y, and at a longitudinal stroke in the longitudinal direction X greater than this transverse stroke.

Due to the symmetry and the alignment, the longitudinal arrangement of the resilient flexible blades 61, 62 makes it possible to compensate for the direction of greater displacement of the centers of mass CM1 and CM2, which move symmetrically relative to the plane symmetry PS.

The isochronous oscillator mechanism 1 according to the invention advantageously comprises rotational stops, and / or translational limit stops in the X and Y directions, and / or translation Z limit stops. These stroke limiting means can be integrated, part of a one-piece construction, and / or be reported.

The masses 51, 52, advantageously comprise abutment means 7, labeled 71, 72, which are arranged to cooperate with complementary abutment means 73, 74, which the crosspiece 4 comprises, and to limit the displacement of the elastic flexible blades. 61, 62, with respect to the crossbar 4, in the event of shocks or similar accelerations.

In the case where a mass 5 is not directly carried by the flexible blade 6, the latter comprises, on the other side relative to the main body of the crosspiece 4, an end plate 45, which is arranged to receive, directly or indirectly, this mass 6. For example, the execution of figures 4 and 5 , as the variant of the second mode of figures 11 and 12 , comprises tips 53, 54, arranged to be attached to such an end plate 45 and to receive a mass 51 or 52. The variant of the first mode of figures 6 and 7 comprises a socket 55 arranged to perform the same function.

On the variant of the first embodiment of the figures 4 and 5 , the ends of the crosspiece 4 each comprise two abutment bearing surfaces 42, which are each arranged to stop an oblique surface 74 that comprises the end plate 45, so as to limit the angle of deformation α (defined in FIG. figure 1 ) that can take the flexible blade 6 relative to its installation in the crossbar 4, and thus constituting stops in rotation. The corresponding end of the crosspiece 4 further comprises a housing 79, in this case a bore, arranged to act as a limit stop around the periphery 48 of the substantially circular end plate 45, to limit X and Y translations. to these different stops, which limit the translations in X and Y, we limit the possible influence of shocks, we protects the flexible blade 6, and preserves this flexible blade 6 against excessive deformation. And of course the possible movement of the CM centers of mass is limited.

Z stops are provided mainly when using end caps 53, 54, sockets 55, or the like; for example the figure 5 illustrates endpieces 53, 54, which either have bores aligned with pins 56 carried by a plate, or comprise bearings aligned with bores of a plate, the bearings thus formed being non-contact in normal operation , and being arranged to take the efforts, especially in Z, in case of shock.

The detail of the figure 6 shows, with regard to the variant with the receipt of a bush 55, a similar arrangement with respect to the stops. The end plate 45 further comprises a lug with stop surfaces 76 arranged to cooperate abutting abutment with complementary surfaces 78 of the cross member 4, to limit the translations. The bushing 55 has a skirt 57 driven on the end plate 45, but the periphery 59 of this bushing 55 remains at a distance from the bore 79 of the cross member 4, and thus ensures with it the safety in translation in X and in Y .

Z-shaped shoulders may also be provided on certain surfaces to form Z-limiting abutment surfaces.

Naturally, these arrangements of abutment, limiting the travel of the flexible blade 6 as shockproof are feasible in variants without intermediate part. And in particular in the case where the fixed support 2, the main elastic connection 3, the crossbar 4, and the primary resonators 10, including the masses 5, form a monolithic assembly.

In the absence of unexpected accelerations such as shocks, the complementary surfaces of the stops must not be in contact with each other, so as to avoid any unnecessary friction detrimental to the quality factor.

Some stroke limiting means may be used to perform damping functions of unwanted vibration modes.

The illustrations of the first and second embodiments thus show the fixed support 2 and the crossbar 4 which are separated only by a narrow groove 30, here called "honey groove", around the main elastic connection 3, which is designed to allow coupling in tuning fork mode. The groove 30 allows limit the angular movement of the crossbar 4, which is insignificant in normal regime, but can occur in case of shock. Advantageously, this groove is filled with a viscous or pasty product, which allows the dissipation of energy in the event of excessive travel.

In particular, it is a question of preventing, or at least of limiting, the duration of a "windshield wiper" mode of operation in which the primary resonators 10 oscillate, no longer in phase opposition, but in phase because it is understood that the compensation of the movements of the centers of mass is then no longer ensured in this phase oscillation regime, which no longer allows the oscillator to be isochronous.

Alternatively, or in addition, it is possible to add cooperating Z surfaces with a solid friction, or viscous, or pasty, and preferably increasing with the speed and / or with the amplitude, for example with conical surfaces corner, as shown on the sketches of the Figures 17 and 18 .

Preferably, the resilient flexible blades 61, 62, which extend substantially in the longitudinal direction X, are short blades, that is to say of a length less than the smallest value between four times their height or thirty times their thickness. It is this short blade characteristic that makes it possible to limit the movements of the center of mass CM concerned.

In normal operation, there is no friction. The modes of oscillation in translation, and displacements in case of shocks are mechanically limited by axes or the like.

In this configuration, the center of mass CM of each primary resonator 10 does not move substantially in the transverse direction Y: it performs a crawling movement, on either side of an average axis parallel to the longitudinal direction X, around from a point on this mean axis.

It is to compensate for this displacement of the center of mass CM along X that the resilient flexible blades 61 and 62 are preferably aligned, these blades being preferably straight.

One embodiment of the invention, called tuning fork in goat horns, is shown on the Figures 8 to 12 . The fixed support 2, the main elastic connection 3, the crosspiece 4, the flexible flexible blades 6, and the end plates 45 of the primary resonators 10, together form a planar monolithic structure, made of silicon, or oxidized silicon, or quartz, or DLC, or the like, which, in the rest position of the mechanism Isochronous oscillator 1, is symmetrical with respect to a plane of symmetry PS, and comprises an elongate cross member 4 extending in the longitudinal direction X, perpendicular to the main elastic connection 3, which extends in the transverse direction Y, and which holds the crossbar 4 on the fixed support 2.

In a similar manner to the first mode, this crosspiece 4 carries a pair of marked masses 51 and 52, mounted symmetrically on either side of the fixed support 2 and the first elastic connection 3. Each of these masses 51, 52 is mounted oscillatingly and biased by an elastic flexible blade 6 respectively marked 61, 62, which is a spiral 8, respectively 81, 82, or a spiral assembly. A first hairspring 81 and a second hairspring 82 are each bonded at its inner turn to an end plate 45 for receiving a mass 51, 52, and attached to the respective end 41, 42 of the sleeper 4. by its external turn.

The masses 51 and 52 each pivot about a virtual pivot axis of position determined relative to the crossbar 4.

Each virtual pivoting axis is, in the rest position of the isochronous oscillator mechanism 1, coinciding with the center of mass CM1, CM2, of the respective mass 51, 52.

In the same way as for the first mode, the masses 51, 52, extend substantially in the transverse direction Y. Preferably each of them comprises an arm connected in its middle to the corresponding flexible blade 6, this arm s' extending substantially parallel in the transverse direction Y, and being either a solid arm as on the figure 3 , either an arm with inertial flyweights at its opposite ends, or substantially punctual as on the figure 8 , in the form of annular sectors, as visible on the Figures 9 to 12 .

To limit the displacement of the centers of mass CM1, CM2, to a transverse stroke relative to the crossbar 4, as small as possible in the transverse direction Y, and to a longitudinal stroke in the longitudinal direction X greater than this transverse stroke, each spiral 81, 82, is section or variable curvature along its development.

The version illustrated by the figures is a variation of variable thickness, optimized to limit the movements of the center of mass CM. The mass 5 pendulum is preferably suspended by a coil thicker than the rest of the spiral.

Preferably, the development of the hairspring is greater than one turn, and in particular greater than 1.5 turns, which is easier to minimize the displacement of the center of mass. For example, a regular decrease in thickness over 270 °, followed by growth in thickness may make it possible to limit the displacement of the center of mass CM to 3 micrometers in Y and 4 micrometers in X. The polar elemental stiffness advantageously passes through an extremum, for example a mini between two maxi, or the opposite.

A satisfactory simulation consists, again, in giving the hairspring an upper stiffness in its portion 89 which is beyond the center of mass towards the outside, than in its portion 88 which lies between the two centers of mass CM1 and CM2.

It can thus be seen that the X-displacements of the centers of mass CM are smaller in this second spiral mode than in the first mode with a straight blade.

One can, of course, play on the height instead of the thickness to obtain a variable section: the choice of the variable thickness corresponds to an elaboration MEMS easier.

In sum, we can make an analogy between this spiral with variable characteristics and a Breguet or Grossmann end curve of a spiral balance-balance spiral.

Once the displacement of the center of mass has been minimized, the symmetrical assembly with respect to the plane of symmetry PS makes it possible to obtain an excellent isochronism.

In normal operation, there is no friction: The modes of oscillation in translation and the displacements in the event of shocks are preferably mechanically limited by axes, or by end pieces 53, 54, or sockets 55.

Preferably, the first hairspring 81 and the second hairspring 82 are attached to the ends 41, 42, in alignment with their respective virtual pivoting axis, in the rest position of the isochronous oscillator mechanism 1.

The figure 16 illustrates another embodiment close to the invention, in which this figure diagram of the second embodiment is extrapolated by suspending each mass, not with a single spring, but with pairs of spirals 81, 810, respectively 82, 820, attached to the crossbar 4, on either side of the centers of mass in the Y direction. This very robust embodiment is, however, closer to a system with crossed flexible blades than the principle of the present invention.

The figure 19 illustrates a variant where the crossbar 4 constitutes a frame surrounding the primary resonators 10, in an example of application to four resonators 10A, 10B, 10C, 10D. It is understood that this inverse architecture of the previous examples is also usable for the implementation of the invention, in all its variants described above, and which are therefore not detailed further here.

The figure 20 illustrates, in this variant of crossbar 4 formed by a frame, the pendulum of the H tuning fork. The crossbar 4 carries a pair 51, 52, masses 5, mounted symmetrically inside the crossbar 4 which forms a frame suspended by the first elastic connection 3 to the fixed structure 2, the masses 51, 52 extending substantially in the transverse direction Y. Each of the masses 51, 52 is oscillatingly mounted around a virtual pivot axis of position determined relative to the crossbar 4, and recalled by an elastic flexible blade 6, respectively 61, 62, which is secured to one side of the frame forming the crossbar 4, the flexible blades 61, 62, extending linearly to the inside the frame.

Similarly, the figure 21 illustrates, in this variant of crossbar 4 formed by a frame, the pendulum fork in goat horns. The crossbar 4 carries a pair 51, 52, masses 5, mounted symmetrically inside the crossbar 4 which forms a frame suspended by the first elastic connection 3 to the fixed structure 2, and substantially in a transverse direction Y perpendicular to the longitudinal direction X in which the centers of mass CM of the primary resonators 10 are movable. Each of the masses 51, 52 is oscillatingly mounted about a virtual pivot axis of position determined with respect to the crossbar 4, and recalled by a spiral 8, respectively 81, 82, which is integral with one side of the frame forming the crossbar 4, these spirals 81, 82, extending inside the frame.

In the illustrated embodiments the masses 5, 5A, 5B, 51, 52, form rockers.

Advantageously, in any embodiment, the masses 51, 52 comprise, for balancing adjustment, inertia and adjustment of oscillation frequency, flyweights 91, 92, and / or housing 93 for receive such weights, preferably in the areas furthest from the ends 41, 42 of the crosspiece 4. Such flyweights advantageously comprise an eccentric insert, for example platinum, to facilitate adjustment by pivoting the insert. Naturally, particular areas of these masses may be assigned to laser ablation, or, conversely, to plasma, ink jet or the like, to provide these settings.

The invention also relates to a clockwork movement 100, in particular a mechanical movement, comprising such an isochronous oscillator mechanism 1.

The invention also relates to a watch 200 comprising such a mechanical movement 100.

In sum, in its totally symmetrical version, the oscillator according to the invention constitutes a tuning fork consisting of two resonators, preferably rotary, spiral, mounted on a cross member connected, preferably visco-elastically, to the plate.

The elastic members of each primary resonator 10 are designed to minimize the displacement of the center of mass CM in the transverse direction Y of the symmetry plane PS of the tuning fork.

The symmetry plane PS of the tuning fork is chosen so that the operating errors due to the positions in the longitudinal direction X perpendicular to the transverse direction Y, cancel out between the two branches of the tuning fork constituted by the primary resonators 10, both sides of the crossbar 4.

The use of rotating primary resonators makes it possible to limit the effect of translational accelerations (shocks and orientation in the gravitational field) on the resonator rhythm.

The architecture of tuning fork type limits the effect of reactions to embedding.

To make the movement of the watch insensitive to positions, the invention minimizes the displacement of the center of mass CM of each primary resonator 10.

• lames en flexion pure, d'où isochronisme ;
• architecture de type diapason, donc des réactions nulles à l'encastrement, et donc un meilleur facteur de qualité ;
• l'élément élastique constitué par la lame flexible joue également le rôle de guidage, il n'est donc pas besoin de pivots, il n'y a donc pas de frottements, et on obtient donc un meilleur facteur de qualité ;
• épaisseur de la lame en forme de spire variable et optimisée pour limiter les déplacements parasites du centre de masse dans la direction Y, d'où une faible erreur de marche en position verticale de la montre :
• lames orientées de manière à ce que l'erreur de marche résiduelle (due aux positions verticales selon la direction longitudinale X) s'annule entre les deux lames du diapason ;
• limitation des courses intégrées, ce qui procure une grande robustesse, et évite la rupture des lames en cas de chocs en X, Y, Z, ou α;
• rainure à miel, permettant un amortissement du mode d'oscillation en « essuie-glace » susceptible de survenir lors d'un choc.

For the embodiment according to the invention, called tuning fork in goat horn, the advantages are:

• blades in pure flexion, hence isochronism;
• architecture of the tuning fork type, therefore zero reactions to embedding, and therefore a better quality factor;
• the elastic element constituted by the flexible blade also acts as a guide, so there is no need for pivots, so there is no friction, and so we get a better quality factor;
• blade thickness in the form of a turn variable and optimized to limit parasitic movements of the center of mass in the Y direction, resulting in a low error of walking in the vertical position of the watch:
• blades oriented so that the residual error of operation (due to the vertical positions in the longitudinal direction X) is canceled between the two blades of the tuning fork;
• limitation of integrated strokes, which provides great robustness, and prevents the blades from breaking in the event of shocks in X, Y, Z, or α;
• Honey groove, allowing a damping of the oscillation mode in "wiper" likely to occur during an impact.

• longueur de la lame minimisée pour limiter les déplacements parasites du centre de masse selon les directions X et Y, ce qui procure donc une faible erreur de marche en position verticale
• lames flexibles rectilignes orientées selon un axe perpendiculaire au plan de symétrie du diapason, de manière à ce que l'erreur due aux positions verticales selon la direction longitudinale X, qui est plus importante que l'erreur selon la direction transversale Y dans ce cas, s'annule entre les deux lames du diapason.

For the first embodiment of the H tuning fork, the main characteristics are similar except for:

• minimized blade length to limit parasitic shifts of the center of mass in the X and Y directions, thus providing a low error in the vertical position
• rectilinear flexible blades oriented along an axis perpendicular to the plane of symmetry of the tuning fork, so that the error due to the vertical positions in the longitudinal direction X, which is greater than the error in the transverse direction Y in this case, is canceled between the two blades of the tuning fork.

In summary, the invention makes it possible to obtain a perfectly isochronous oscillator, very compact, requiring no adjustment other than the inertia of the masses, and very easy assembly.

Claims (19)

1. Isochronous clockwork oscillator mechanism (1) of the tuning fork type comprising a fixed support (2), a principal elastic connection (3) and a cross-piece (4) carrying a plurality of primary resonators (10), each carrying at least one mass (5) supported by a spiral (8) constituting an elastic return means and that is arranged to function in bending and that is embedded in said cross-piece (4), in which said primary resonators (10) have at least one identical resonant mode, and are arranged to vibrate with a relative phase shift equal to 2π/n where n is the number of said primary resonators (10) and are arranged with a symmetry in space such that the resultant of forces and torques applied by said primary resonators (10) on said cross-piece (4) is zero, and in which said primary resonators (10) are arranged in space such that the resultant of their functioning errors due to gravity is zero, and in which the number of said primary resonators (10) is even, characterised in that said cross-piece (4) is fixed to said fixed support (2) by said elastic principal connection (3), the stiffness of which is greater than the stiffness of each said spiral (8).
2. Isochronous oscillator mechanism (1) according to claim 1, characterised in that said primary resonators (10) are rotary.
3. Isochronous oscillator mechanism (1) according to claim 1 or 2, characterised in that the stiffness of said principal elastic connection (3) is more than the total of the stiffnesses of all of said spirals (8).
4. Isochronous oscillator mechanism (1) according to one of claims 1 to 3, characterised in that each said primary resonator (10) is arranged to oscillate in a plane.
5. Isochronous oscillator mechanism (1) according to one of claims 1 to 4, characterised in that each said primary resonator (10) is arranged to oscillate in planes parallel to each other or coincident.
6. Isochronous oscillator mechanism (1) according to claim 5, characterised in that each said primary resonator (10) is arranged to oscillate in the same plane.
7. Isochronous oscillator mechanism (1) according to one of claims 1 to 6, characterised in that each said primary resonator (10) is plane.
8. Isochronous oscillator mechanism (1) according to one of claims 1 to 7, characterised in that all said primary resonators (10) are identical and are arranged to be symmetrical about a plane of symmetry (PS) extending parallel to a transverse direction (Y) perpendicular to a longitudinal direction (X) along which the centres of mass (CM) of said primary resonators (10) are free to move.
9. Isochronous oscillator mechanism (1) according to claim 8, characterised in that said principal elastic connection (3) lies along said transverse direction (Y).
10. Isochronous oscillator mechanism (1) according to one of claims 1 to 9, characterised in that each said spiral (8) has a variable cross-section along its development.
11. Isochronous oscillator mechanism (1) according to one of claims 1 to 10, characterised in that said spirals (8) comprise a first spiral (81) and a second spiral (82), each of which is connected at its internal turn to an end plate (45) on which a mass (51, 52) will be fitted, and connected to the corresponding end (41, 42) of said cross-piece (4) through its external coil.
12. Isochronous oscillator mechanism (1) according to one of claims 1 to 11, characterised in that said cross-piece (4) carries a pair (51, 52) of said masses (5) mounted symmetrically on each side of said fixed support (2) and said principal elastic connection (3), said masses (51, 52) extending on each side of said cross-piece (4) that extends along a longitudinal direction (X) along which the centres of mass (CM) of said primary resonators (10) are free to move, and approximately along a transverse direction (Y) perpendicular to said longitudinal direction (X), each of said masses (51, 52) being mounted free to oscillate about a virtual pivot axis in a position determined relative to said cross-piece (4) and pulled back by one said spiral (8) that is fixed to one end (41, 42) of said cross-piece (4), said spirals (8) extending on each side of said cross -piece (4).
13. Isochronous oscillator mechanism (1) according to one of claims 1 to 11, characterised in that said cross-piece (4) carries a pair (51, 52) of said masses (5) mounted symmetrically inside said cross-piece (4) that forms a frame suspended from said principal elastic connection (3) to said fixed structure (2), and approximately along a transverse direction (Y) perpendicular to a longitudinal direction (X) along which the centres of mass (CM) of said primary resonators (10) are free to move, each of said masses (51, 52) being mounted free to oscillate about a virtual pivot axis in a position determined relative to said cross-piece (4) and pulled back by one said spiral (8) that is fixed to one side of said frame forming said cross-piece (4), said spirals (8) extending inside said frame.
14. Isochronous oscillator mechanism (1) according to one of claims 1 to 13, characterised in that said fixed support (2) and said cross-piece (4) are separated by a narrow groove (30) around said principal elastic connection (3) that provides coupling in tuning fork mode, said groove (30) being arranged to limit the angular movement of said cross-piece (4) and being filled with a viscous or paste material designed to dissipate energy if the amplitude should become excessive.
15. Isochronous oscillator mechanism (1) according to one of claims 1 to 14, characterised in that said masses (51, 52) are balances.
16. Isochronous oscillator mechanism (1) according to claim 12 or 13, characterised in that said cross-piece (4) is straight and extends along said longitudinal direction (X).
17. Isochronous oscillator mechanism (1) according to claim 12, characterised in that said masses (51, 52) are bars comprising end masses at the points furthest from the opposite ands (41, 42) of said cross-piece (4).
18. Clockwork movement (100) comprising at least one isochronous oscillator (1) according to one of claims 1 to 17.
19. Watch (200) comprising at least one movement (100) according to claim 18.

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