HK1233335A1

HK1233335A1 - Mechanical timepiece movement provided with a feedback system for the movement

Info

Publication number: HK1233335A1
Application number: HK17106889.2A
Authority: HK
Inventors: Pascal Winkler; Gianni Di Domenico; Thierry Conus; Jean-Luc Helfer
Original assignee: Eta Sa Manufacture Horlogère Suisse
Priority date: 2015-08-11
Filing date: 2017-07-10
Publication date: 2018-01-26

Description

Mechanical timepiece movement provided with a feedback system for the movement

Technical Field

The present invention relates to a mechanical timepiece movement provided with a feedback system for the movement.

Background

Mechanical watch movements have been subject to considerable improvements over the years, in particular in order to adjust or regulate the oscillation frequency of a balance spring used as a resonator of a local oscillator. Conventional mechanical watch movements and in particular their swiss lever escapements are characterized by their robustness (robustness) to the shocks experienced by the watch. This means that the state of the watch is generally not affected by a single impact. However, the efficiency of such escapements is not very high, for example around 30%. Furthermore, the swiss lever escapement does not allow the use of resonators with high frequencies or low amplitudes.

WO patent application No.2006/045824 a2 discloses a regulating member for returning an oscillating balance to a balanced position. An escapement mechanism is also provided for maintaining the oscillation of the balance about its equilibrium position. To achieve this, the balance is connected to at least one movable permanent magnet and the regulating member has a fixed permanent magnet, so as to generate a magnetic field that returns the balance to its equilibrium position. There is no description of a feedback system capable of adjusting the oscillation frequency of the sprung balance, which is a disadvantage.

In order to maintain the resonator of the local oscillator at a high frequency, the principle of the swiss lever escapement must be adjusted. To achieve this, an increase in the frequency of the adjustment member requires more energy to maintain the oscillator. To reduce energy, the oscillator mass or inertia may be reduced to reduce oscillation amplitude, increase the quality factor of the oscillator, or increase the efficiency of energy transfer between the drive member and the adjustment member. Thus, for a conventional swiss lever escapement, excessive energy is consumed due to multiple accelerations and stops per second. Even if the swiss lever and its wheel are made as light as possible, this does not make it easy to obtain a high-frequency oscillator.

In the mechanical movement proposed by De Bethune, a magnetic escapement with continuous sinusoidal transmission of energy is proposed. The mechanical drive member transmits the torque to the reduction gear train. At the end of the gear train, a magnetic rotor transfers the energy to a resonator of the local oscillator, to which a permanent magnet is fixed. The gear train speed is synchronized with the natural resonator frequency. The resonator as the tuning member controls the time metric. The speed of movement of the time indicator needle is controlled by an accurate and regular division of time.

Such a resonator can replace a conventional balance spring to better meet the requirements and constraints of high frequency oscillations and thus improve accuracy. There are no longer any specific attachment points. The resonator is more rigid and allows the use of the first natural vibration mode. The quality factor is higher than conventional oscillators even at low amplitudes.

However, according to the above-described embodiment for a De Bethune movement, there is no shock resistance. Under such conditions, the pointer tends to advance quickly after any impact. Furthermore, there is no description of a feedback system for simply and accurately adjusting the oscillation frequency of the balance as described in the present invention, which is a drawback.

The present invention seeks to address an arrangement for resonators using local oscillators having high quality factors, high frequencies and/or low amplitudes. This is achieved without giving up the impulse robustness of the swiss lever escapement.

Disclosure of Invention

It is therefore a main object of the present invention to remedy the above drawbacks by proposing a mechanical timepiece movement provided with a feedback system capable of precisely adjusting the oscillation frequency of the resonator of the local oscillator of the mechanical movement.

To this end, the invention relates to a mechanical timepiece movement including the features of independent claim 1.

Particular embodiments of the mechanical timepiece movement are defined in dependent claims 2 to 22.

One advantage of the mechanical timepiece movement according to the invention lies in the fact that: the accuracy of the reference oscillator can be optimized without having to worry about its shock resistance and thus the shock resistance of the local oscillator without having to worry about its accuracy.

Another advantage is that it is possible to provide a product that complies with the aesthetic codes of the watchmaking industry due to the presence of the balance as a local oscillator, while improving the accuracy through the use of a reference oscillator that can be at high frequencies.

Drawings

The objects, advantages and features of a mechanical timepiece movement provided with a feedback system for the mechanical movement will appear more clearly in the following non-limiting description with reference to the accompanying drawings, in which:

figure 1 shows a schematic view of the various components of a conventional mechanical timepiece movement in conjunction with a movement feedback system according to the invention,

figure 2 shows in greater detail the elements making up a conventional mechanical movement in conjunction with the feedback system according to the invention,

figure 3 shows a simplified view of the components of the feedback system according to the first embodiment and mainly of the combination of the reference oscillator and the frequency comparator according to the invention,

FIG. 4 shows the interaction torque (interaction torque) between the excitation wheel and the tuning fork with permanent magnet of the reference oscillator as a function of the rotational speed of the wheel in the feedback system according to the first embodiment of FIG. 3,

figure 5 shows a first embodiment of the adjustment mechanism of the feedback system for adjusting the oscillation frequency of the resonator of the local oscillator according to the invention,

fig. 6 shows a second embodiment of an adjustment mechanism of a feedback system for adjusting the oscillation frequency of a resonator of a local oscillator according to the invention, an

Fig. 7 shows a simplified view of the components of the feedback system according to the second embodiment with an input excitation wheel to compare the speed of the local oscillator and the reference oscillator of the feedback system according to the invention.

Detailed Description

In the following description, all those components of a mechanical timepiece movement that are well known to those skilled in the art will be described only in a simplified manner.

As seen schematically in fig. 1, there is shown a mechanical timepiece movement 1 provided with a feedback system 2 for accurately adjusting the speed or operation of a conventional mechanical movement 1'. The conventional mechanical movement 1' comprises a mechanical energy source 11, a transmission assembly 12 and a local oscillator 13, said mechanical energy source 11 being at least one barrel.

The transmission assembly 12 comprises a set of gearwheels 12 driven by the barrel 11 at a first end wheel. The wheels of the drive wheel set 12 are preferably toothed wheels. The last driving wheel of the transmission wheel set 12 drives the escapement of the local oscillator 13. The local oscillator 13 also comprises a resonator in the form of a balance spring.

The feedback system 2 may be connected to an input of the local oscillator 13 to control, inter alia, the oscillation frequency of the resonator of the local oscillator. The connection between the conventional mechanical movement 1' and the feedback system 2 can be realized via the last wheel of the transmission wheel set 12.

The feedback system 2 first comprises a reference oscillator 21 which is accurate, i.e. at least more accurate than the resonator of the local oscillator 13. The feedback system 2 further comprises a frequency comparator 22 and an adjustment mechanism 23, the frequency comparator 22 being connected or combined with the reference oscillator or resonator 21 to compare the speed of the two oscillators 21, 13. The adjustment mechanism 23 can adjust the oscillation frequency of the resonator of the local oscillator 13 based on the comparison result of the frequency comparator 22. The frequency of a resonator, such as the balance of the local oscillator 13, can thus be adjusted by means of an adjustment mechanism, which will be described below, in order to slow down or speed up the resonator of the local oscillator.

It should be noted that the "speed" or frequency of the local oscillator or reference oscillator refers to the rotational speed or oscillation frequency of the wheel to which the local oscillator and/or reference oscillator is connected.

Fig. 2 shows in greater detail the various elements of a conventional mechanical movement of mechanical timepiece movement 1. The conventional mechanical movement thus comprises a barrel 11, the barrel 11 having an external toothing for meshing with the central toothed shaft 121' of the first wheel 121 of the set of driving wheels 12. A multiplication of the rotation speed of the first wheel 121 with respect to the rotation speed of the outer ring gear of the barrel is thus obtained.

The set of driving wheels 12 may also comprise a second wheel 122, the central toothed shaft 122' of which is driven by the external toothed ring of the first wheel 121. There is also a multiplication of the rotational speed of the second wheel 122, which rotates faster than the first wheel 121. A third wheel 123 may also be provided and driven by the outer ring gear of the second wheel 122 via a central toothed shaft 123'. There is also a multiplication of the rotational speed of the third wheel 123, which rotates faster than the second wheel 122. This third wheel 123 may be the last wheel of the set of driving wheels 12 for driving one or more time indicator hands of the mechanical watch.

The last wheel 123 of the transmission wheel set 12 drives the escapement of the local oscillator 13. The escapement mechanism may comprise an escape wheel 16 whose central gear 16' is driven by the last wheel 123 and a swiss lever 15 meshing with the escape wheel and cooperating in a conventional manner with the balance 14. Balance 14 has a balance spring 14' attached at one end to the balance wheel rotating staff and at the other end to a balance spring stud, which is usually attached to the watch plate. The oscillation frequency of the balance is controlled and regulated by a feedback system 2.

A first embodiment of the feedback system 2 is shown in fig. 3. The feedback system includes a frequency discriminator. Since the local oscillator of a conventional mechanical movement is not precise but shock-resistant, the movement excites the more precise reference oscillator or resonator 32, 32 ', 33' of the feedback system. The speed or frequency of the reference resonator is thus compared with the speed or frequency of the resonator of the local oscillator by means of the frequency comparators 35, 36'. The frequency comparator output controls an element of the adjustment mechanism to adjust the speed of the resonator of the local oscillator.

It should be noted that the reference resonator is combined with a frequency comparator. There is a magnetic interaction with a spinning wheel connected to a conventional mechanical movement to excite the reference resonator and compare the speed or frequency of the oscillator.

The excitation wheel 31 may be directly connected to one of the sets of transmission wheels of a conventional mechanical movement.The excitation wheel may also be one of the sets of transmission wheels or there may be a multiplier or a divider (division arrangement) between one of the sets of transmission wheels and the excitation wheel 31. The exciter wheel 31 is thus set at a certain rotational speed V_extRotating at a speed proportional to the angular excitation frequency or pulse of the local oscillator. The excitation wheel 31 has a number N of peripheral teeth. The number of teeth N may be odd, for example the excitation wheel may have 9 teeth.

The reference oscillator or resonator of this feedback system has at least one permanent magnet 33 arranged at the free end of the arm 32 of the resonator, which is attached via a base 34 to a movable frame 35 mounted on the plate of the watch movement. The permanent magnet 33 is arranged in the vicinity of the excitation wheel 31 and preferably the magnetic polarization of the magnet is oriented towards the center of the excitation wheel 31.

The permanent magnet 33 is attracted towards the excitation wheel 31 when there are teeth near the magnet and less attracted towards the excitation wheel when the magnet faces the empty space between two teeth of the excitation wheel. Because the exciting wheel rotates at a certain speed V_extRotates, so the magnet 33 will thus be at the second frequency ω by magnetic interaction with said excitation wheel 31₀And (6) oscillating.

During the rotation of the excitation wheel 31 and according to its number of peripheral teeth N, based on the natural rotation speed V of the wheel_extTo determine the excitation frequency omega_ext. Excitation frequency omega_extThus being equal to N.V_extWhere N is the number of teeth of the excitation wheel. The number of teeth N may be odd, for example the excitation wheel may have 9 teeth. Therefore, the excitation frequency ω can be set_extOscillation frequency omega with reference oscillator₀A comparison is made to compare the speeds of the two oscillators.

Preferably, two arms 32, 32 'may be provided, each having a permanent magnet 33, 33' mounted at their first end to define a tuning fork. The second ends of the two arms 32, 32' are joined and attached to a frame 35 via a base 34. The two permanent magnets 33, 33 'are arranged in the vicinity of the excitation wheel 31 and at diametrically opposite positions, wherein the excitation wheel 31 is located between the two permanent magnets 33, 33'.

The moving frame 35 is preferably a hollow wheel arranged coaxially with the excitation wheel 31. The ring gear 35 is held free to rotate on the plate by means of roller or pin or ball bearings 38 in contact with the inner surface of the ring gear 35. The number of roller or pin or ball bearings 38 must be above 3 to enable the frame or ring wheel to rotate about the same axis of rotation as the excitation wheel. The frame or ring gear 35 is however held in a defined position by at least one return spring 36 or two return springs 36, 36' attached on one side to the plate. Preferably, the return springs 36, 36' are connected to the ring gear at diametrically opposite positions.

When the exciting wheel 31 rotates at a certain speed V_extUpon rotation, the tuning fork reference oscillator will oscillate at an oscillation frequency ω₀Is activated. The excitation of the reference oscillator is obtained due to the rotation of the excitation wheel 31, the excitation wheel 31 being made of ferromagnetic material to magnetically interact with one or more permanent magnets 33, 33 'carried at the first ends of the arms 32, 32'. The excitation wheel 31 may also be provided with ferromagnetic parts only on or in the teeth for magnetically interacting with the permanent magnets 33, 33'. The ferromagnetic material may also be continuously deposited on the peripheral teeth of the excitation wheel 31. Thus also generating a magnetically interactive or locking torque. Since the activation wheel rotates in a counter-clockwise direction, the frame 35 will also tend to move in a counter-clockwise direction while being held by the return springs 36, 36'.

The rotational speed of the exciter wheel 31 can be gradually increased and then, in principle, stabilized at the reference rotational frequency ω₀Nearby. As described above, the lock torque exists in this case. However, if the interaction torque is further increased, the system unlocks and the speed of the excitation wheel 31 is then only limited by friction. It is therefore sought to synchronize the speeds of the two oscillators via a feedback system.

As also shown in FIG. 4, when the angular excitation frequency ω is at the interaction torque with respect to the angular excitation frequency, the torque increases as the angular excitation frequency ω increases_extNear the lock frequency, a lock torque occurs. MoveThe frame 35 will thus be in a position to balance the locking torque and the torque of the return springs 36, 36'. The frame also comprises a toothed portion for engagement with, for example, the output wheel 37. Angular position of output wheel 37Thereby proportionally representing the difference omega between the angular or rotational frequencies_ext-ω₀To allow the local oscillator to be adjusted via an output wheel 37, the output wheel 37 constituting one of the elements of the adjustment mechanism.

It should also be noted that the frame 35 and the return springs 36, 36' may be incorporated in a unitary member. Further, the reference oscillator may be in a different form than a tuning fork. A permanent magnet can also be arranged on the excitation wheel, the tuning fork having ferromagnetic arms 32, 32'. The end of each arm faces the excitation wheel to be excited by the rotation of said excitation wheel 31.

Fig. 5 shows a simplified view of a first embodiment of a feedback system adjustment mechanism for adjusting the speed or frequency of a local oscillator in accordance with a difference determined in a frequency comparator of the feedback system. The local oscillator is represented in fig. 5 only by balance 14 and balance spring 14'.

The adjustment mechanism is represented by an output wheel 37 of the feedback system, which engages with a toothed base, for example in the form of a circular arc, of the moving adjustment member 137. The regulating member is mounted to rotate on the watch plate about an axis parallel to the axis of rotation of the balance but external to the sprung balance 14. The adjustment member thus comprises a beak at the end of the arm opposite the toothed portion. Adjusting the beak can move to the last coil closer or further away from the balance spring 14 'according to the beak's rotation angle θ, which depends on the frequency comparison in the feedback system.

The beak of the movement of the adjustment member 137 acts on the effective length L of the balance spring from a given elongation₀The above. The period of oscillation of the balance depends on the effective length of the balance spring 14'. During oscillation, the balance spring alternately retracts and extends. If an obstacle such as a rigid beak is placed on the last wheel of the balance springOn the stretch trajectory, the effective length of the balance spring is then instantaneously changed during oscillation. This causes a reduction of the average effective length and thus a shortening of the oscillation period.

It is obviously conceivable not to use the output wheel 37, but to allow the toothed portion of the frame to mesh directly with the toothed portion of the adjustment member 137.

Fig. 6 shows a simplified view of a second embodiment of a feedback system adjustment mechanism for adjusting the speed or frequency of a local oscillator in accordance with a difference determined in a frequency comparator of the feedback system. As in fig. 5, the local oscillator is represented in fig. 6 only by balance 14 and balance spring 14'.

For this second embodiment of the adjustment mechanism, the adjustment member 137 comprises a toothed base, for example in the form of a circular arc, which can be directly engaged with a toothed portion of the frequency comparator frame. The regulating member is mounted to rotate on the watch plate about an axis parallel to the axis of rotation of the balance but external to the sprung balance 14. The regulating member also comprises an arcuate portion of complementary shape to the outer surface of balance 14 to vary the friction induced by the air on the balance. The arcuate portion is disposed on an opposite side of the toothed portion with respect to the rotational axis of the setting member. According to the difference omega of the rotation frequencies_ext-ω₀The arcuate portion may be moved closer to or further from the outer surface of the balance to adjust the speed or frequency of the local oscillator. Thus, by carefully selecting the isochronism profile of the balance used, the balance frequency decreases with the increase in friction caused by the arc of the regulating member 137 close to the balance, and vice versa.

It should be noted that, for both embodiments described with reference to fig. 5 and 6, regulating member 137 is linearly movable to adjust the oscillation frequency of balance 14.

The regulation of the oscillation frequency of balance 14 can be achieved, in addition to the air-induced friction, by a magnetic coupling between regulating member 137 and said balance.

With respect to the feedback system and according to another embodiment, different arrangements of reference oscillators may be provided to magnetically interact with the excitation wheel to determine the speed or frequency of the two oscillators. The excitation wheel may include magnetic tracks annularly disposed on one surface and regularly spaced from each other. These annularly distributed magnetic tracks are centered on the axis of rotation of the exciter wheel. When the excitation wheel rotates, at least one magnetic coupling element of the permanent magnet as a reference oscillator is excited by each rotating magnetic track of the excitation wheel. The permanent magnet is elastically held on a moving frame that can be moved angularly or linearly to compare the frequencies of the two oscillators and enable the regulating mechanism to adjust the oscillation frequency of the balance.

Fig. 7 shows a second embodiment of the feedback system. In this second embodiment, the reference oscillator is integrally combined with the frequency comparator to control the adjustment mechanism. There is also a magnetic interaction with a spinning wheel attached to a conventional mechanical movement to excite the reference resonator and compare the speed or frequency of the oscillator.

As described in detail with reference to fig. 3, the excitation wheel 41 of this second embodiment may be directly connected to one of the sets of transmission wheels of a conventional mechanical movement. The excitation wheel 41 may thus be the last wheel in a set of transmission wheels or a wheel in a set of transmission wheels arrangement connected to said set of transmission wheels. The excitation wheel 41 rotates at a speed V representative of the frequency of the local oscillator (i.e. proportional to the oscillation frequency of the balance 14)_extAnd (4) rotating. The excitation wheel 41 may excite a reference oscillator, which in this case is a crossed strip resonator.

The reference oscillator or resonator is a resonator with crossed strips 44, 45, 48, 49. It comprises on the arcuate section 42 at least one permanent magnet 43 close to the toothed excitation wheel 41. A rigid arcuate section, which may be made of a metallic material, is connected to a first substrate 46 via two first intersecting flexible strips 44, 45. These first cross elastic strips 44, 45 extend at a distance from each other in two parallel planes. These two parallel planes are also parallel to the plane of the excitation wheel 41 and to the watch plate on which the various elements of the mechanical movement and of the feedback system are mounted.

The first substrate 46 is also fixed to the second plate 47 of the complementary part of the crossed strip resonator. The second plate 47 is connected to a fixed plate 50 via two second crossed flexible strips 48, 49, the fixed plate 50 being fixedly mounted on the watch plate. These second crossed elastic strips 48, 49 extend at a distance from each other in two parallel planes, also parallel to the two planes of the first elastic strips 44, 45. These second crossed flexible strips 48, 49 are located between the first elastic strips 44, 45 and the watch plate.

The first and second substrates 46, 47 are movable and move angularly according to the locking torque between the resonator and the wheel. The first and second substrates 46, 47 are shown in arcuate form, but may be in another general shape, such as a rectangular parallelepiped, and form only one entity. During the rotation of the excitation wheel 41, preferably made of ferromagnetic material, the arcuate section 42 together with its permanent magnets 43 is at a frequency ω in the plane of the excitation wheel₀And (6) oscillating. Magnetic interaction occurs and, depending on the speed of rotation of the excitation wheel, an angular displacement of the plates 46, 47 is caused by a defined locking torque.

In this second embodiment, the adjustment mechanism is here formed by an adjustment beak 53, the adjustment beak 53 being attached, for example, on the second base plate 47. On the adjustment beak 53 there is arranged a second permanent magnet 52, which cooperates for example with an aluminium plate 51 arranged below the beak and on the watch plate. This aluminum plate 51 may dampen the vibration of beak 53 following the oscillation of arcuate section 42 acting as a Foucault brake.

Comparison omega according to the rotation frequency_ext-ω₀Plates 46 and 47 are displaced with respect to their equilibrium position. The angular displacement of plates 46, 47 moves beak 53 in the direction of balance spring 14' of balance 14 to adjust the oscillation frequency of the local oscillator, as described with reference to fig. 5. If balance 14 oscillates at a frequency that is too low, beak 53 advances towards the last coil of balance 14' to reduce the effective length of said balance spring and vice versa in the case of an oscillation frequency that is too high.

According to a different variant embodiment, the arched section 42 can be replaced by a flywheel carrying at least one permanent magnet 43 or having a magnetized portion made in the metallic material of the flywheel to be excited by the excitation wheel 41 when the excitation wheel 41 rotates. The flywheel may be connected to a first base plate 46 by two first crossing flexible strips 44, 45 remote from each other and crossing on a virtual pivot axis parallel to the axis of rotation of the excitation wheel. The intersecting straps may be arranged at an angle a relative to the pivot axis, which may be between 60 ° and 80 °.

Two second crossed flexible strips 48, 49 are also distant from each other, but are arranged between the first crossed strips 44, 45 and the watch plate, on which the fixed plate 50 of the combined reference oscillator and frequency comparator is fixed.

From the description given above, a person skilled in the art can design many variant embodiments of a mechanical timepiece movement provided with a feedback system for the movement without departing from the scope of the invention as defined by the claims. It is conceivable to provide the excitation wheel with at least one permanent magnet to interact with the ferromagnetic metal part of the reference resonator so that it oscillates at a determined frequency. The excitation wheel may be a circular wheel without teeth but with ferromagnetic parts regularly spaced from each other and arranged over the entire circumference of the excitation wheel to magnetically interact with the permanent magnet of the reference oscillator. The frequency comparator frame may be linearly displaceable when the arm or magnetized element of the reference oscillator is magnetically coupled with the excitation wheel to control the adjustment of the adjustment mechanism.

Claims

1. Mechanical timepiece movement (1) comprising at least one barrel (11), a transmission wheel set (12) driven by the barrel at one end, an escapement with a local oscillator (13) in the form of a resonator of a balance, and a feedback system (2) for the mechanical timepiece movement, the escapement being driven at the other end of the transmission wheel set (12),

characterized in that the feedback system (2) comprises at least one accurate reference oscillator (21) combined with a frequency comparator (22) for comparing the frequencies of both oscillators, the feedback system further comprising an adjustment mechanism (23) for adjusting the resonator of the local oscillator to slow down or speed up the resonator based on the comparison in the frequency comparator.

2. Mechanical timepiece movement (1) according to claim 1, wherein the reference oscillator of the feedback system (2) is excited by magnetic interaction via a rotating excitation wheel connected to one of the sets of transmission wheels (12).

3. Mechanical timepiece movement (1) according to claim 2, wherein the excitation wheel (31) is a toothed wheel made of ferromagnetic material and the reference oscillator (21) comprises at least one permanent magnet (33) arranged at a first end of an arm (32) fixed to a moving frame (35) of the frequency comparator via a base (34), the permanent magnet (33) being arranged in the vicinity of the excitation wheel (31) so as to be attracted when each tooth of the rotating excitation wheel passes and to produce an oscillation at the reference frequency of the reference oscillator.

4. Mechanical timepiece movement (1) according to claim 3, wherein the reference oscillator (21) comprises two arms (32, 32 ') attached to the base (34), a first end of each arm carrying a permanent magnet (33, 33 ') respectively to form a tuning fork, and the first and second permanent magnets (33, 33 ') being attracted towards the rotating excitation wheel as each tooth passes.

5. Mechanical timepiece movement (1) according to claim 4, wherein two permanent magnets (33, 33 ') are arranged in the vicinity of the excitation wheel (31) and at diametrically opposite positions, wherein the excitation wheel (31) is located between the two permanent magnets (33, 33').

6. A mechanical timepiece movement (1) according to claim 4, wherein the excitation wheel (31) includes an odd number N of teeth.

7. A mechanical timepiece movement (1) according to claim 6, wherein the number of teeth N of the excitation wheel is at least equal to 9.

8. Mechanical timepiece movement (1) according to claim 3, wherein the moving frame (35) of the frequency comparator (22) is mounted on a plate of the mechanical timepiece movement while being held in a defined position via at least one return spring (36) so as to be displaced linearly or angularly according to the frequency difference of the two oscillators.

9. Mechanical timepiece movement (1) according to claim 8, wherein the moving frame (35) is a hollow wheel arranged coaxially to the excitation wheel (31), mounted by means of roller or pin or ball bearings so as to rotate freely on the plate, and the moving frame (35) is held in a defined position via two return springs (36, 36') connected to the moving frame at diametrically opposite positions.

10. Mechanical timepiece movement (1) according to claim 8, characterized in that it is equal to N · V by definition_extExcitation frequency ω of_extOf the excitation wheel (31) is_extAnd the number of teeth N of the excitation wheel, the moving frame (35) of the frequency comparator (22) being set to the oscillation frequency ω of the reference oscillator₀And said excitation frequency ω_extThe difference between them is angularly displaced proportionally to control the regulating mechanism (23) and to regulate the oscillation frequency of the balance.

11. Mechanical timepiece movement (1) according to claim 1, wherein the adjusting mechanism (23) includes at least one adjusting member (137) connected to the frequency comparator (22), the moving adjusting member being arranged to be displaced linearly or angularly to adjust the oscillation frequency of the sprung balance.

12. A mechanical timepiece movement (1) according to claim 11, wherein the adjustment member (137) mounted to rotate on a plate comprises a beak part and a base part driven at the output of the frequency comparator (22), the beak part being movable to be closer to or further from the last coil of the balance spring (14') according to the angle of rotation of the beak part in accordance with the frequency comparison in the feedback system.

13. Mechanical timepiece movement (1) according to claim 11, wherein the adjustment member (137) mounted to rotate on a plate comprises a base portion driven at the output of the frequency comparator (22) and an arcuate portion complementary in shape to the outer surface of the balance (14) to vary the friction caused by air on the balance according to the frequency comparison in the feedback system.

14. Mechanical timepiece movement (1) according to claim 2, wherein the excitation wheel (31) comprises at least portions made of ferromagnetic material regularly spaced from each other and arranged on the entire periphery of the excitation wheel to magnetically interact with at least one permanent magnet (33) of the reference oscillator.

15. Mechanical timepiece movement (1) according to claim 2, wherein the toothed excitation wheel (31) includes a ferromagnetic portion at least on or within the teeth to magnetically interact with at least one permanent magnet (33) of the reference oscillator.

16. Mechanical timepiece movement (1) according to claim 2, wherein the toothed excitation wheel (31) comprises a continuously deposited layer of ferromagnetic material on the peripheral teeth of the excitation wheel (31) to magnetically interact with at least one permanent magnet (33) of the reference oscillator.

17. Mechanical timepiece movement (1) according to claim 2, wherein the excitation wheel (31) comprises regularly spaced permanent magnets arranged on the periphery of the excitation wheel to magnetically interact with at least one arm (32) made of ferromagnetic material of the reference oscillator so as to cause the reference oscillator to oscillate at a determined reference frequency.

18. A mechanical timepiece movement (1) according to claim 2, wherein the excitation wheel (41) is arranged to excite, by magnetic interaction, a reference oscillator in the form of a crossed-strip resonator (44, 45, 48, 49).

19. Mechanical timepiece movement (1) according to claim 18, wherein the resonator comprises an arcuate section (42) or a circular flywheel having a magnetized portion or at least one permanent magnet (43) facing the excitation wheel (41) at a short distance or having portions made of ferromagnetic material regularly spaced from each other and arranged at the periphery, the arcuate section (42) or the circular flywheel being connected to a first base plate (46) by two first crossed flexible strips (44, 45) extending at a distance from each other in two parallel planes, the moving first base plate (46) being fixed on a moving second base plate (47), the second base plate (47) being connected to a fixed plate (50) by two second crossed flexible strips (48, 49), the fixed plate being fixedly mounted on a mechanical timepiece movement plate, the second crossing flexible strips (48, 49) extend at a distance from each other in two parallel planes, which are also parallel to the two planes of the first crossing flexible strips (44, 45).

20. Mechanical timepiece movement (1) according to claim 19, wherein the first base plate (46) and the second base plate (47) of the frequency comparator are angularly displaced according to the frequency comparison of the two oscillators to control the adjustment mechanism (23).

21. A mechanical timepiece movement (1) according to claim 20, wherein the adjustment mechanism (23) includes an adjustment beak (53) attached to the first base plate (46) and to the second base plate (47) which can be moved closer to or further from the last coil of the balance spring (14') according to an oscillator frequency comparison in the feedback system.

22. Mechanical timepiece movement (1) according to claim 21, wherein the adjustment beak (53) comprises a permanent magnet (52) for braking above an aluminium plate (51) arranged on a plate of the mechanical timepiece movement to damp the vibrations of the adjustment beak.