CH710691A2 - Isochronous timepiece resonator. - Google Patents

Abstract

The invention relates to an equilibrium clock-tuning isochronous oscillator mechanism (1), comprising a fixed support (2) and a cross-member (4) carrying primary resonators (10A, 10B) each comprising at least one mass (5A, 5B ) carried by a resilient flexible blade (6A, 6B) constituting an elastic return means, arranged to work in bending, and embedded in the cross member (4). The primary resonators (10A, 10B) have at least one identical resonance mode and are arranged to vibrate in a phase shift between them of the value 2π / n, where n is the number of primary resonators (10A, 10B). They are arranged in a symmetry in the space such that the resultant of the forces and torques applied on the crossbar (4) is zero. The crossbar (4) is fixed to the fixed support (2) by a main elastic connection (3), whose rigidity is greater than the rigidity of each resilient flexible blade (6A, 6B).

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 carrier beam of a plurality of primary resonators each having at least one mass carried by a resilient flexible blade constituting a means of recall elastic 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 further relates to a watch comprising at least one such movement.

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

Background of the invention

In a conventional mechanical watch, the friction of the air on the balance, the friction of the pivots in their bearings and 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 involves the design of movements able to compensate for the effects of gravity on their constituents.

Summary of the invention

The invention proposes to solve jointly the problem of isochronism and that of obtaining the best quality factor possible. 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.

For this purpose, the invention relates to an isochronous clock oscillator mechanism of the tuning fork type, comprising a fixed support and a carrier beam of a plurality of primary resonators each comprising at least one mass carried by an elastic flexible blade constituting an elastic return means which is arranged to work in bending and which is embedded in said cross member, characterized in that said primary resonators have at least one identical resonance mode, and are arranged to vibrate in a phase shift between them of the value 2π / n, where n is the number of said primary resonators, and are arranged in a symmetry in space such that the resultant of the forces and torques applied by said primary resonators on said crossbar is zero, and further characterized in that said crossbar is fixed to said fixed support by a main elastic connection, whose rigidity is greater than the rigidity said first resilient flexible blade, and in that said primary resonators are arranged in space so that the resultant of their operating errors due to gravitation is zero.

According to a particular characteristic of the invention, said primary resonators are rotary.

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

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the accompanying drawings, in which: <tb> Fig. 1 <SEP> represents, schematically and in plan view, an isochronous clock oscillator mechanism according to the invention, of the tuning fork type, comprising a fixed support which carries, by a main elastic connection, a cross member carrying two resonators planar primary planes, symmetrical with respect to a plane of symmetry, and each comprising a mass carried by an elastic flexible blade arranged to work in bending and embedded in the cross; <tb> fig. 2 <SEP> simulates, schematically: <tb> <SEP> • <SEP> 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, <tb> <SEP> • <SEP> 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 , <tb> <SEP> • <SEP> the influence of gravity on a mechanism according to the invention which combines the two previous ones, and the gait diagram corresponding to a virtually zero defect; <tb> fig. 3 <SEP> shows schematically and in plan view, a first embodiment of the invention, called "tuning fork H" in a simplified version; <tb> fig. 4 <SEP> represents, schematically and in perspective, a more elaborate variant of H tuning fork, shown in FIG. 5 exploded; <tb> fig. 6 <SEP> illustrates exploded, and with a local detail, a tuning fork H in a configuration similar to that of fig. 4 and 5, without axes, and <tb> figs. 7A to 7H <SEP> represent the components and the assembly of this H-tuning fork of FIG. 6; <tb> figs. 8 and 9 <SEP> show, schematically and in plan view, a second embodiment of the invention, called "tuning fork horns" in simplified versions; <tb> fig. 10 <SEP> represents, schematically and in perspective, and with a local detail, a more elaborate variant of goat horn tuning fork; <tb> fig. 11 <SEP> illustrates a burst of goat horn in a configuration similar to that of FIG. 10, without axes, and FIGS. 12A to 12H show the components and the assembly of this H-tuning fork of FIG. 11; <tb> figs. 13 and 14 <SEP> 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 a axis parallel to these two planes; <tb> fig. <SEP> illustrates another variation of tuning fork with two resonators, each comprising a spiral spring recessed at a first end on a common cross-piece 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; <tb> fig. 16 <SEP> shows, schematically and in plan view, a mechanism near the tuning fork of goat horns of FIG. 8, which comprises, at each end of the crossbar, a pair of spirals both linked to the same respective mass at their inner coil, and attached to the respective cross on either side of this mass; <tb> figs. 17 and 18 <SEP> are sketches illustrating surfaces cooperating in friction in case of drift, this friction increasing with the amplitude in the case of FIG. 18; <tb> fig. 19 <SEP> shows, 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; <tb> fig. <SEP> shows, schematically and in plan, another variant of cross-member formed by a frame, in a straight-wave oscillator, constituting the counterpart of the H-tuning fork; <tb> fig. 21 <SEP> shows, schematically and in plan, another variant of cross-member formed by a frame, in a spiral oscillator, constituting the counterpart of the goat horn tuning fork; <tb> fig. <SEP> 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 achieve a resonator mechanism with the least possible losses, and that is the sensitive month chronometrically to its orientation in the gravity field.

The invention is aimed at reducing losses, in particular due to friction pivots, and displacements of the recess.

The inventive step consists in eliminating 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 to use a spring element to ensure the guiding function. This elastic element is then advantageously higher, thicker and more rigid than a conventional elastic element such as a spiral spring or the like, 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 implementation of a tuning fork type structure.

However, it is necessary to minimize the losses: indeed, when a flexible blade resonator operates, the quality factor is good during the back and forth movement, but the reaction torque to the embedding results in losses.

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

The invention is more particularly described below, without limitation, 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 mounting of these primary resonators is made in such a way that they have at least one identical resonance mode, and that the resultant forces and torques to the embedding is zero.

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

The primary resonators 10 are the equivalent of the arms that includes a conventional fork fork, and crosses 4 the equivalent of the common part of the tuning fork protruding these arms.

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

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

Figs. 1 to 17 illustrate examples with two primary resonators, FIG. 19 illustrates an example with four primary resonators.

And this crossbar 4 is fixed to the fixed support 2 by a main elastic connection 3, whose rigidity is greater than the rigidity of each resilient flexible blade 6. This characteristic provides 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 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 flexible flexible blades 6 that comprise the primary resonators 10.

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

Preferably, the primary resonators 10 are rotary, 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 are moving the centers of mass CM primary resonators 10 is called the longitudinal direction X. A transverse direction Y is substantially perpendicular to this longitudinal direction X. A direction Z completes the direct trihedron.

In the variants illustrated in FIGS. 1 to 17, the cross member 4 is straight and extends in the longitudinal direction X.

In an advantageous embodiment, but not limiting, which corresponds to the variants illustrated by 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 direction transverse 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 visible in the examples of the figures .

Preferably, the primary direction which connects the embedding point 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.

FIG. 1 illustrates a simplified embodiment of an isochronous clock oscillator mechanism 1 according to the invention, of 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 carrier of two planar primary resonators 10A, 10B, symmetrical with respect to a plane of symmetry PS, and each having 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 in FIGS. 1, 3, 6, 8 to 11, not limiting of the invention, 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 primary resonator 10 given is minimal in the transverse direction Y where compensation is not provided, and so that the displacements of the different centers of mass CM of the given primary resonators 10 are compensated with respect to one another in the longitudinal direction X: if, as in the case of the figures, the isochronous oscillator mechanism 1 comprises two resonators primary 10A and 10B arranged back to back on both sides of the cross 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 allows obtaining 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 recess 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 recess of the elastic flexible blade 6 in the associated mass 5, as shown in FIG. 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 manufacturing, particularly by the implementation of micro-machinable materials according to the "MEMS," LIGA ", or the like, 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 resilient 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 cross member 4, and the elastic 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 cross member 4, and the resilient flexible blades 6 of the primary resonators 10, form a monolithic assembly.

Such an embodiment provides elastic blades 6 called "high leaf", which have a height very large compared to their thickness, especially at least five times higher than thick, and particularly at 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 cross member 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 parallel planes between them, or in a same plan.

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

In particular embodiments, as shown in FIGS. 13 to 16, these primary resonators 10 each extend in a separate plane.

It is nevertheless possible to implement the invention with primary resonators 10 arranged differently in space.

Figs. 1 to 12 illustrate an isochronous oscillator mechanism 1, all primary resonators 10 are identical, in even 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 connection main elastic band 3 and perpendicularly to a longitudinal direction X in which are moving the centers of mass CM of the primary resonators 10.

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 the variants of FIGS. 1 to 8, according to a first embodiment detailed below, the elastic flexible blades 6 are straight in the longitudinal direction X. The centers of mass CM of the primary resonators 10 are considered in their alignment at rest. This arrangement guarantees the insensitivity to the positions of the isochronous oscillator mechanism 1 according to the invention, 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 a piece of clock.

The sketches of FIG. 2 allow 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 according to the invention which combines the two previous ones, and the corresponding step diagram which shows an advance or a delay close to zero, thanks to the alignment in the opposite direction, which allows a balancing, by averaging the 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 center of mass in X is of very small value, of the same order of magnitude as the defect due to the displacements of the centers of mass in Y, which is limited to 3 or 4 micrometers, for a blade of length 1 mm, 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 embodiment, thus reinforces the character of insensitivity to gravitation due to the rotary operation of the primary resonators 10. The symmetry thus compensates for any residual error.

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

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

On the variants of FIGS. 9 to 12, according to a second embodiment detailed below, the resilient flexible blades 6 are spiral wound around the centers of mass CM primary resonators 10 considered.

A variant illustrated in FIGS. 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. plans P1 and P2.

Another variant of tuning fork illustrated in FIG. 15 comprises 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 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 displacement limitation of the centers of mass CM 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, but both obeying the logic of the invention, are presented below: a first tuning fork mode "in H", and a second tuning fork mode "horns goat" .

The first mode of tuning fork in H, is shown in Figs. 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 5 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 the middle to the corresponding flexible blade 6, this arm extending substantially parallel in the transverse direction Y, and being either a solid arm as in FIG. 3, an arm having inertial flyweights at its opposite ends, or substantially punctual as in FIG. 1, or in the form of annular sectors, as visible in FIGS. 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 resilient return means and which is integral with an 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, s preferably extend linearly in the extension and on either side of the crossbar 4.

Each virtual pivot axis is, in the rest position of the isochronous oscillator mechanism 1, coincident 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 to a stroke longitudinal 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 by relative to the plane of 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 Z-translation limitation stops. These means of stroke limitation can be integrated, be part of a one-piece construction, and / or be reported.

The masses 51, 52, advantageously comprise stop means 7, labeled 71, 72, which are arranged to cooperate with complementary abutment means 73, 74, which comprises the crossbar 4, and limit the movement of resilient flexible blades 61, 62, relative 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, it comprises, on the other side relative to the main body of the crossbar 4, an end plate 45, which is arranged to receive, directly or indirectly, this mass 6. For example, the execution of FIGS. 4 and 5, as the variant of the second mode of FIGS. 11 and 12, comprises end pieces 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 embodiment of FIGS. 6 and 7 comprises a socket 55 arranged to perform the same function.

In the variant of the first embodiment of FIGS. 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 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. at these different stops, which limit translations in X and Y, it limits the possible influence of shocks, 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 in the case of use of tips 53, 54, sockets 55, or the like; for example fig. 5 illustrates tips 53, 54, which either comprise bores aligned with pins 56 carried by a plate, or comprise bearing surfaces aligned with bores of a plate, the bearings thus formed being non-contact in operating conditions normal, and being arranged to take the efforts, especially in Z, in case of shock.

The detail of FIG. 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-shoulders may, again, be formed on certain surfaces to form Z-limiting abutment surfaces.

Naturally, these stops, limiting the movement of the flexible blade 6 as shockproof are achievable 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 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 tuning fork mode. The groove 30 limits the angular movement of the crossbar 4, which is insignificant in normal operation, but can occur in case of impact. 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 "wiper-type" mode of operation in which the primary resonators 10 oscillate, no longer in phase opposition, but 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 or corner surfaces, as visible in the sketches of FIGS. 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 a point on this mean axis.

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

The second mode of tuning fork horns is shown in FIGS. 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 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 connection main elastic 3, which extends in the transverse direction Y, and which maintains the crossbar 4 on the fixed support 2.

[0101] In a similar manner to the first embodiment, this crosspiece 4 carries a pair of 5 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 the middle to the corresponding flexible blade 6, which arm extending substantially parallel in the transverse direction Y, and being either a solid arm as in FIG. 3, an arm having inertial flyweights at its opposite ends, or substantially punctual as in FIG. 8, or in the form of annular sectors, as shown in FIGS. 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 race transverse, each spiral 81, 82 is section or variable curvature along its development.

The version illustrated by the figures is a variable thickness variant, optimized to limit the movements of the center of mass CM. The pendulum mass 5 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 part 89 which is beyond the center of mass towards the outside, than in its part 88 which is between the two centers of mass CM1 and CM2.

It is thus noted that the X displacements of the centers of mass CM are less in this second spiral mode than in the first straight-blade mode.

We can, of course, play on the height instead of the thickness to obtain a variable section: the choice of 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 balance sprung-balance spiral.

Once the displacement of the center of mass minimized, symmetry mounting relative to the plane of symmetry PS provides excellent isochronism.

In normal operation, there is no friction: The modes of oscillation in translation and shocks in the event of shocks are preferably mechanically limited by pins, or by bits 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.

[0115] FIG. 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 hairspring, but with pairs of spirals 81, 810, respectively 82, 820, attached to the crosses 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.

[0116] FIG. 19 illustrates a variant where the crosspiece 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.

[0117] FIG. 20 illustrates, in this variant of the crossbar 4 formed by a frame, the pendulum of the fork H. 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 mounted oscillatingly about 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 integral with one side of the frame forming the crossbar 4, the flexible blades 61, 62, extending linearly to the inside the frame.

[0118] Similarly, FIG. 21 illustrates, in this variant of crossbar 4 formed by a frame, the pendulum fork horns goat. 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 embodiments illustrated 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 housings 93 to receive such flyweights, preferably in the most remote areas of the ends 41, 42 of the crossbar 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, with flexion blades, mounted on a connected cross member, preferably viscoelastically, at the platinum.

The elastic elements 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 plane of symmetry PS of the tuning fork is chosen so that the operating errors due to the positions along 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, on both sides of the crossbar 4.

The use of rotary primary resonators makes it possible to limit the effect of translation 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.

For the second embodiment of the invention said tuning fork horn goat, 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.

For the first embodiment of the invention known as a tuning fork in H, 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 provides a perfectly isochronous oscillator, very compact, requiring no adjustment other than the inertia of the masses, and assembly very easy.

Claims (29)

An equilibrium isochronous oscillator mechanism (1) of tuning fork type, comprising a fixed support (2) and a crossbar (4) carrying a plurality of primary resonators (10) each comprising at least one mass (5) carried by an elastic flexible blade (6) constituting an elastic return means and which is arranged to work in flexion and which is embedded in said crosspiece (4), characterized in that said primary resonators (10) have at least one identical resonance mode , and are arranged to vibrate in a phase shift between them of the value 2π / n, where n is the number of said primary resonators (10), and are arranged in a symmetry in space such that the resultant of the applied forces and torques by said primary resonators (10) on said crossbar (4) is zero, and further characterized in that said crossbar (4) is fixed to said fixed support (2) by a main elastic connection (3), whose rigidity is superior ure to the rigidity of each said elastic flexible blade (6), and in that said primary resonators (10) are arranged in space so that the resultant of their operating errors due to gravitation is zero. 2. Isochronous oscillator mechanism (1) according to claim 1, characterized in that said primary resonators (10) are rotatable. 3. Isochronous oscillator mechanism (1) according to claim 1 or 2, characterized in that the rigidity of said main elastic connection (3) is greater than the total stiffness of all said resilient flexible blades (6). 4. Isochronous oscillator mechanism (1) according to one of claims 1 to 3, characterized 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, characterized in that all said primary resonators (10) are arranged to oscillate in planes parallel to each other or together. 6. Isochronous oscillator mechanism (1) according to claim 5, characterized in that all said primary resonators (10) are arranged to oscillate in the same plane. 7. Isochronous oscillator mechanism (1) according to one of the preceding claims, characterized in that all said primary resonators (10) are planar. 8. Isochronous oscillator mechanism (1) according to one of the preceding claims, characterized in that all said primary resonators (10) are identical, in even number, and arranged in symmetry with respect to a plane of symmetry (PS) s extending parallel to a transverse direction (Y) perpendicular to a longitudinal direction (X) in which the centers of mass (CM) of said primary resonators (10) are movable. 9. Isochronous oscillator mechanism (1) according to claim 8, characterized in that said main elastic connection (3) extends in said transverse direction (Y). 10. Isochronous oscillator mechanism (1) according to one of the preceding claims, characterized in that said resilient flexible blades (6) that it comprises are straight blades (61, 62). Isochronous oscillator mechanism (1) according to claim 10, characterized in that said resilient flexible blades (6) are short blades (61, 62) of a length less than the smallest value between four times their height or thirty times their thickness, which extend substantially in said longitudinal direction (X). Isochronous oscillator mechanism (1) according to claim 10 or 11, characterized in that said primary resonators (10) are even in number, and in that said elastic flexible blades (61, 62) which they comprise are straight and aligned two by two. 13. Isochronous oscillator mechanism (1) according to one of claims 10 to 12, characterized in that said opposite ends (41, 42) comprise one and the other of the rotational abutment means limiting the angular stroke of said short blade (61, 62) respectively. 14. Isochronous oscillator mechanism (1) according to one of claims 10 to 13, characterized in that said opposite ends (41, 42) comprise one and the other of the abutment means in translation limiting displacement in said direction longitudinal (X) and in said transverse direction (Y) of the centers of mass (CM) of said respective masses (5). 15. Isochronous oscillator mechanism (1) according to one of claims 10 to 14, characterized in that said opposite ends (41, 42) comprise one and the other of the abutment means in translation limiting the displacement in one direction (Z), orthogonal to said longitudinal direction (X) and said transverse direction (Y), centers of mass (CM) of said respective masses (5). 16. Isochronous oscillator mechanism (1) according to one of claims 10 to 15, characterized in that said crossbar (4) carries a pair (51, 52) of said masses (5), mounted symmetrically on both sides. other said fixed support (2) and said first elastic connection (3), said masses (51, 52) extending substantially in a transverse direction (Y) perpendicular to a longitudinal direction (X) in which the centers are movable of mass (CM) of said primary resonators (10), and forming the lateral bars of an H of which said crossmember (4) constitutes the horizontal bar, each of said masses (51, 52) being mounted oscillatingly about an axis virtual pivoting position determined relative to said crossbar (4) and recalled by a said elastic flexible blade (6) which is integral with one end (41, 42) of said crossbar (4), said flexible blades (6) extending linearly in the extension e t on both sides of said crossbar (4). 17. Isochronous oscillator mechanism (1) according to claim 16, characterized in that said cross member (4) is straight and extends in said longitudinal direction (X). 18. Isochronous oscillator mechanism (1) according to one of claims 10 to 15, characterized in that said crossbar (4) carries a pair (51, 52) of said masses (5), mounted symmetrically inside. of said cross member (4) which forms a frame suspended by said first elastic connection (3) to said fixed structure (2), said masses (51, 52) extending substantially in a transverse direction (Y) perpendicular to a longitudinal direction (X) according to which the centers of mass (CM) of said primary resonators (10) are movable, each of said masses (51, 52) being mounted oscillatingly about a virtual pivot axis of position determined with respect to said cross-member (4) and recalled by a said resilient flexible blade (6) which is secured to one side of said frame forming said crossbar (4), said flexible blades (6) extending linearly within said frame. 19. Isochronous oscillator mechanism (1) according to one of claims 1 to 9, characterized in that said primary resonators (10) are even in number, and in that said elastic flexible blades (6) which they comprise are spirals (8). 20. Isochronous oscillator mechanism (1) according to claim 19, characterized in that each said spiral (8) is variable in section along its development. 21. Isochronous oscillator mechanism (1) according to claim 19 or 20, characterized in that said resilient flexible blades (6) comprise a first balance spring (81) and a second balance spring (82) which are each connected at the level of its internal turn to an end plate (45) for receiving a mass (51; 52), and attached to the respective end (41, 42) of said cross member (4) by its outer turn. 22. Isochronous oscillator mechanism (1) according to one of claims 19 to 21, characterized in that said crossbar (4) carries a pair (51, 52) of said masses (5), mounted symmetrically on both sides. 'other said fixed support (2) and said first elastic connection (3), said masses (51, 52) extending on either side of said crossbar (4), which extends in a longitudinal direction ( X) wherein the centers of mass (CM) of said primary resonators (10) are movable, and substantially in a transverse direction (Y) perpendicular to said longitudinal direction (X), each of said masses (51, 52) being mounted oscillating about a virtual pivot axis of position determined with respect to said crossbar (4) and recalled by a said spiral (8) which is integral with an end (41, 42) of said crossbar (4), said spirals (8) extending on either side of said crossbar (4). 23. Isochronous oscillator mechanism (1) according to one of claims 19 to 21, characterized in that said crossbar (4) carries a pair (51, 52) of said masses (5), mounted symmetrically inside. said crossbar (4) which forms a frame suspended by said first elastic connection (3) to said fixed structure (2), and substantially in a transverse direction (Y) perpendicular to said longitudinal direction (X) in which the centers are movable; mass (CM) of said primary resonators (10), each of said masses (51, 52) being mounted oscillatingly about a virtual pivot axis of position determined relative to said crossbar (4) and recalled by a said spiral (8) which is secured to one side of said frame forming said crossbar (4), said spirals (8) extending inside said frame. Isochronous oscillator mechanism (1) according to one of the preceding claims, characterized in that said fixed support (2) and said crosspiece (4) are separated by a narrow groove (30) around said main elastic connection (3). ) which provides tuning fork coupling, said groove (30) being arranged to limit the angular movement of said crossbar (4), and being filled with a viscous or pasty product, arranged to ensure the dissipation of energy in case of deflection too important. 25. Isochronous oscillator mechanism (1) according to one of the preceding claims, characterized in that said masses (51, 52) are pendulums. 26. Isochronous oscillator mechanism (1) according to claim 8, characterized in that said cross member (4) is straight and extends in said longitudinal direction (X). Isochronous oscillator mechanism (1) according to claim 22, characterized in that said masses (51, 52) are bars comprising end weights at the points furthest away from opposite ends (41, 42) of said cross member. (4) which extends in a longitudinal direction (X) in which the centers of mass (CM) of said primary resonators (10) are movable, said masses (51, 52) extending substantially in a transverse direction (Y) perpendicular to said longitudinal direction (X), and having end weights at the points furthest away from opposite ends (41, 42) of said cross member (4). 28. Movement (100) of clockwork comprising at least one isochronous oscillator mechanism (1) according to one of the preceding claims. 29. Watch (200) comprising at least one movement (100) according to the preceding claim.