Method for creating an oscillator mechanism having a rotational flexible guide to reduce out-of-plane vibration

Abstract

To provide a method of setting up a resonator mechanism for a timepiece, in which a secondary oscillation frequency may be different from a multiple of a reference oscillation frequency.SOLUTION: Provided is a method of setting up a resonator mechanism for a timepiece, comprising a structure and an anchoring block which is suspended from the structure by a flexible suspension. The method comprises a first step of measuring a reference oscillation frequency of an inertial element about a Z direction in an XY plane, a second step of measuring a secondary oscillation frequency of the inertial element about an X direction in a YZ plane or about a Y direction in an XZ plane, a third step of comparing the secondary oscillation frequency with the reference oscillation frequency, to check that the secondary oscillation frequency has a value substantially different from a multiple of the reference oscillation frequency, and in the event that the secondary oscillation frequency has a value close to or substantially equal to a multiple of the reference oscillation frequency, a fourth step of adapting the flexible suspension or substituting the flexible suspension with another flexible suspension, so as to have a configuration of the flexible suspension modified so that the secondary oscillation frequency is substantially different from a multiple of the reference oscillation frequency.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for developing an oscillator for a timepiece, comprising a structure, an anchor block from which at least one inertial element is suspended, and a plurality of substantially vertical elastic blades each fixed to the anchor block at a first end and to the inertial element at a second end, and a virtual pivot.

[0002] The present invention relates to the field of timepiece oscillators, in particular to the field of timepiece oscillators comprising elastic blades that function as a means for returning the oscillator.

Background Art

[0003] The torsional stiffness of the suspension is a delicate point for most timepiece oscillators comprising elastic blades forming at least one coil spring or flexible guide, especially for oscillators with crossed blades. The shock resistance also depends on this torsional stiffness. In fact, during an impact, the stress received by the blade rapidly reaches a very high value, thereby shortening the distance that the part can move before yielding. There are many variations of shock absorbers for timepieces. However, their main purpose is to protect the fragile pivot of the oscillator axis and not to protect elastic elements such as conventional coil springs.

[0004] According to patent document 1 in the name of ETA Manufacture Horlogere Suisse and its derivatives (the teachings of which can be directly used in the present invention), with a new mechanism architecture, by using a flexible guide with a lever escapement having a very small lift angle, it becomes possible to maximize the quality factor of the oscillator, and the oscillator can be further improved with respect to its sensitivity to impacts in a specific direction. Therefore, the objective is to protect the blade from damage during impacts. The anti-impact systems proposed to date for oscillators with flexible guides only protect the blade from impacts in a specific direction, not from impacts in all directions, or have the defect of allowing the virtual pivot to move slightly according to its oscillatory rotation, which should be avoided as much as possible.

[0005] Patent document 2 or patent document 3 in the name of ETA Manufacture Horlogere Suisse describes a watch oscillator mechanism comprising a structure supporting an anchor block by a flexible suspension, an inertial element being suspended from the anchor block, the inertial element oscillating according to a first rotational degree of freedom RZ under the action of a restoring force applied by a virtual pivot comprising a first elastic blade fixed to the inertial element and the anchor block respectively, the flexible suspension being configured to allow some mobility of the anchor block in all degrees of freedom other than the first rotational degree of freedom RZ in which only the inertial element is movable in order to avoid disturbing its oscillation, and the stiffness of the suspension in the first rotational degree of freedom RZ being much greater than the stiffness of the virtual pivot in the same first rotational degree of freedom RZ.

[0006] Patent Document 4 or Patent Document 5 in the name of ETA Manufacture Horlogere Suisse describes a watch oscillator mechanism comprising a structure and an anchor block with at least one inertial element suspended so as to oscillate with a first rotational degree of freedom RZ about a pivot axis extending in a first direction Z. Each inertial element is subject to a restoring force applied by a virtual pivot comprising a plurality of substantially vertical elastic blades, each fixed to the anchor block at a first end and to the inertial element at a second end. Each said elastic blade is deformable essentially in a plane XY perpendicular to the first direction Z.

[0007] When the oscillator mechanism is operating, the inertial element oscillates about the Z direction in the XY plane at a reference oscillation frequency. Further, the inertial element performs rotational secondary oscillations about the X direction on the one hand and about the Y direction on the other hand. These secondary oscillations are oscillation modes known as "out-of-plane", i.e. outside the XY plane.

[0008] These "out-of-plane" secondary oscillations have a more or less limited influence on the movement of the speed regulating mechanism. However, if the frequencies of these secondary oscillations are multiples of the reference frequency of the inertial element in the XY plane, the secondary oscillations become large and interfere with the operation of the oscillator. Therefore, it is important that the frequencies of the secondary oscillations differ by multiples of the reference frequency.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0010] In order to improve the flexible suspension and avoid the above-mentioned drawbacks, the present invention proposes to improve the oscillator mechanism of Patent Document 4 or Patent Document 5 in the name of ETA Manufacture Horlogere Suisse.

Means for Solving the Problems

[0011] For this purpose, the present invention is a method for creating an oscillator mechanism for a timepiece, the oscillator mechanism comprising a structure and an anchor block, at least one inertial element being suspended from the anchor block and configured to oscillate with a first rotational degree of freedom RZ about a pivot axis extending in a first direction Z, the inertial elements each receiving a restoring force applied by a virtual pivot comprising a plurality of substantially vertical elastic blades fixed to the anchor block at a first end and to the inertial element at a second end, each said elastic blade being deformable essentially in a plane XY perpendicular to the first direction Z, and the anchor block being suspended from the structure by a flexible suspension configured to allow movement of the anchor block.

[0012] The features of the present invention are that the method · a first step of measuring a reference oscillation frequency of the inertial element about the Z direction in the XY plane; · a second step of measuring at least one secondary oscillation frequency of the inertial element about the X direction in the YZ plane or at least one secondary oscillation frequency of the inertial element about the Y direction in the XZ plane; · a third step of comparing the secondary oscillation frequency with the reference oscillation frequency and confirming that the secondary oscillation frequency has a value substantially different from a multiple of the reference oscillation frequency; · When the secondary vibration frequency has a value close to or substantially equal to a multiple of the reference vibration frequency, in order to change the configuration of the flexible suspension so that the secondary vibration frequency is substantially different from a multiple of the reference vibration frequency, a fourth step of adapting the flexible suspension or replacing the flexible suspension with another flexible suspension is worth noting in this regard.

[0013] By this method, an oscillator mechanism is created that suppresses and avoids large secondary vibrations centered on the X and Y directions in a plane perpendicular to the XY vibration plane, such as the XZ plane or the YZ plane. Thereby, the accuracy of the oscillator mechanism is improved.

[0014] Furthermore, the modification or replacement of the flexible suspension described in this method has no obvious influence on the reference vibration centered on the Z direction.

[0015] According to a specific embodiment of the present invention, the flexible suspension includes a lateral movement table having a flexible guide between the anchor block and a first intermediate mass fixed to the structure directly or using a plate flexible in the first direction Z. The lateral movement table includes at least two preferably linear lateral flexible blades or rods that extend symmetrically about a horizontal axis intersecting the pivot axis in the second direction X. The first secondary vibration frequency measured in the second step is centered on the Y direction in the XZ plane.

[0016] According to a specific embodiment of the present invention, the fourth step consists of replacing or adapting the flexible suspension by changing the number of lateral flexible blades or rods of the lateral movement table.

[0017] According to a specific embodiment of the present invention, the fourth step consists of replacing or adapting the flexible suspension by changing the stiffness of the lateral flexible blades or rods of the lateral movement table.

[0018] In certain embodiments of the present invention, the stiffness is changed by changing the thickness or length of the lateral flexible blades or rods of the lateral movement table.

[0019] According to a particular embodiment of the present invention, the fourth step consists of replacing or adapting said flexible suspension by increasing the distance between at least two lateral flexible blades or rods of the lateral movement table or between all the lateral flexible blades or rods of the lateral movement table.

[0020] According to a particular embodiment of the present invention, said flexible suspension comprises a vertically movable table, flexibly guided between said anchor block and the second intermediate mass, preferably linear and symmetrically extending about a vertical axis intersecting the pivot axis in said third direction Y, and at least two vertically flexible blades or rods, and the secondary vibration frequency measured in the second step is centered on direction X in the YZ plane.

[0021] According to a particular embodiment of the present invention, the fourth step consists of replacing or adapting said flexible suspension by changing the number of vertically flexible blades or rods of the vertically movable table.

[0022] According to a particular embodiment of the present invention, the fourth step consists of replacing or adapting said flexible suspension by changing the stiffness of the vertically flexible blades or rods of the vertically movable table.

[0023] In certain embodiments of the present invention, the stiffness is changed by changing the thickness or length of the vertically flexible blades or rods of the vertically movable table.

[0024] According to a particular embodiment of the present invention, the fourth step consists in replacing or adapting said flexible suspension by increasing the distance between at least two vertical flexible blades or rods of the vertical movement table or between all the vertical flexible blades or rods.

[0025] According to a particular embodiment of the present invention, in the fourth stage, the same reference vibration frequency as that measured in the first stage is maintained.

Brief Description of the Drawings

[0026] Further features and advantages of the present invention will become apparent from the following detailed description with reference to the accompanying drawings.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0027] The present invention relates to a method 40 for adjusting a clock oscillator mechanism as shown, for example, in FIGS. 1 to 3. The adjustment process 40 according to the present invention will be described in detail in the latter half of the specification.

[0028] As shown in FIGS. 1 to 3, this embodiment of the clock oscillator mechanism 100 includes a structure 1 and an anchor block 30, from which at least one inertial element 2 is suspended and configured to oscillate with a first rotational degree of freedom RZ about a pivot axis D extending in a first direction Z. The inertial element 2 includes a template 20. The pendulum is in the shape of a bone and includes a straight portion having spherical portions at both ends. Each spherical portion can include a small weight 29 for adjusting the inertia of the inertial element 2. This inertial element 2 receives a restoring force applied by a virtual pivot 200 including a plurality of substantially vertical elastic blades 3, each fixed to the anchor block 30 at a first end and to the inertial element 2 at a second end. Each elastic blade 3 is essentially deformable in a plane XY perpendicular to the first direction Z.

[0029] The anchor block 30 is suspended from the structure 1 by a flexible suspension 300, which is configured to allow movement of the anchor block 30 according to five flexible degrees of freedom of the suspension, the five flexible degrees of freedom being · a first degree of freedom of translational movement along a first direction Z, · a second degree of freedom of translational movement along a second direction X orthogonal to the first direction Z, · a third degree of freedom of translational movement along a third direction Y orthogonal to the second direction X and the first direction Z, · a second rotational degree of freedom RX about an axis extending in the second direction X, and · a third rotational degree of freedom RY about an axis extending in the third direction Y are.

[0030] The principle is to use the torsional flexibility of the moving table to better manage the torsional stiffness of the suspension. For this purpose, the blades of the XY table are oriented such that the direction of maximum torsional flexibility is oriented towards the axis of rotation of the vibrator. Their torsional flexibility is managed by bringing the blades closer to each other.

[0031] Thus, the flexible suspension 300 comprises a laterally movable table 32 that is flexibly guided between an anchor block 30 and a first intermediate mass 303 fixed to the structure 1 directly or using a plate 301 that is flexible in the first direction Z. The laterally movable table 32 comprises lateral blades 320 that are linear and extend in a second direction X or lateral flexible rods.

[0032] In a particular non - limiting embodiment, as shown in the figures, the flexible suspension 300 also comprises a longitudinally movable table 31 that is flexibly guided between the anchor block 30 and a second intermediate mass 305. The longitudinally movable table 31 comprises longitudinal blades 310 that are linear and extend in a third direction Y or longitudinal flexible rods. Also, the laterally movable table 32 that is flexibly guided between the second intermediate mass 305 and the first intermediate mass 303 comprises lateral blades 320 that are linear and extend in the second direction X or lateral flexible rods.

[0033] More specifically, the longitudinal axis D1 intersects the transverse axis D2, and in particular, the longitudinal axis D1, the transverse axis D2, and the pivot axis D pass through the same point.

[0034] More specifically, the vertical movement table 31 and the horizontal movement table 32 each comprise at least two flexible blades or rods, each blade or rod being characterized by its thickness in the second direction X when the blade or rod extends in the third direction Y or vice versa, its height in the first direction Z, and its length in the direction in which the strip or rod extends, the length being at least five times greater than the height, for example, the height being at least the same size as the thickness, more specifically at least five times greater than this thickness, and even more specifically at least seven times greater than this thickness.

[0035] More specifically, the horizontal movement table 32 comprises at least two horizontal flexible blades or rods that are parallel to each other and of the same length. FIGS. 1 to 3 show a non-limiting variant having four parallel horizontal slats, and more specifically each slat is composed of two half-slats arranged in two overlapping levels and extending parallel to each other in the first direction Z. These half-blades may be completely separated from each other or may be joined to each other by adhesion or the like, or in the case of silicon conversion by the growth of SiO2 or the like. Of course, the vertical movement table 31, if present as it is optional, can follow the same construction principle. The number, arrangement and cross-section of these blades or rods can be changed without departing from the present invention.

[0036] The principle is to use the torsional flexibility of the movement table to better manage the torsional stiffness of the suspension. For this purpose, the blades of the XY table are oriented such that the direction of maximum torsional flexibility faces the axis of rotation of the pendulum. Their torsional flexibility is managed by bringing the blades closer together or further apart from each other.

[0037] Thus, the flexible suspension 300 includes a laterally movable table 32 that is flexibly guided between an anchor block 30 and a first intermediate mass 303 fixed to the structure 1 directly or using a plate 301 that is flexible in the first direction Z. The laterally movable table 32 includes a lateral blade 320 or a laterally flexible rod that is linear and extends in the second direction X.

[0038] In certain non-limiting embodiments, as shown in the figures, the flexible suspension 300 also includes a vertically movable table 31 that is flexibly guided and has a flexible guide between the anchor block 30 and a second intermediate mass 305. The vertically movable table includes a vertical blade 310 or a vertically flexible rod that is linear and extends in the third direction Y. Also, a laterally movable table 32 that is flexibly guided between the second intermediate mass 305 and the first intermediate mass 303 includes a lateral blade 320 or a laterally flexible rod that is linear and extends in the second direction X.

[0039] More specifically, the longitudinal axis D1 intersects the transverse axis D2, and in particular, the longitudinal axis D1, the transverse axis D2, and the pivot axis D pass through the same point.

[0040] More particularly, the vertically movable table 31 and the laterally movable table 32 each include at least two flexible blades or rods. Each blade or rod is characterized by its thickness in the second direction X when the blade or rod extends in the third direction Y, or vice versa, its height in the first direction Z, and its length in the direction in which the strip or rod extends. The length is, for example, at least five times greater than the height, the height is at least the same size as the thickness, more particularly at least five times greater than this thickness, and even more particularly at least seven times greater than this thickness.

[0041] More specifically, the lateral movement table 32 comprises at least two lateral flexible blades or rods that are parallel to each other and of the same length. FIGS. 1 to 3 show a non-limiting variant having four parallel lateral slats. More specifically, each slat is composed of two half-slats that are arranged in two overlapping levels and extend in the first direction Z with respect to each other. These half-blades may be completely separated from each other, or may be joined to each other by adhesion or the like, or by growth of SiO2 in the case of silicon conversion. Of course, the longitudinal movement table 31, if present since it is optional, can follow the same principle of construction. The number, arrangement and cross-section of these blades or rods can be changed without departing from the present invention.

[0042] More specifically, the lateral blades or rods of the lateral movement table 32 are parallel to the transverse axis D2 and have a first plane of symmetry passing through the pivot axis D.

[0043] More specifically, the lateral blades or rods of the lateral movement table 32 are parallel to the transverse axis D2 and have a second plane of symmetry perpendicular to the pivot axis D.

[0044] In a variant not shown, the longitudinal blade or linear flexible rod 310 is a rod having a square or circular cross-section, the height of which is equal to the thickness.

[0045] In a particular variant, the oscillator mechanism 100 comprises at least one flexible blade 302 extending in a plane perpendicular to the pivot axis D and a plate 301 fixed to the structure 1 and the first intermediate mass 303, the plate 301 being configured to allow movement of the first intermediate mass 303 in the first direction Z. More specifically, the plate 301 comprises at least two flexible blades 302 on the same plane. However, such a plate 301 is optional if the height of the blades of the XY movement table is small compared to the height of the flexible blade 3, in particular if it is less than one third of the height of the flexible blade 3.

[0046] In a particular variant, the flexible suspension 300 is preferably made in one piece from silicone.

[0047] In an advantageous embodiment, the oscillator mechanism 100 comprises a monoblock assembly that groups together at least the anchor block 30, the base of at least one inertial element 2, the flexible pivot 200, the flexible suspension 300, the first intermediate mass 303, and the lateral movement table 32, and comprises at least one frangible element 319 configured to secure the components of the monoblock assembly during their assembly to the structure 1, such that upon breaking of the frangible element 319, all the movable components of the monoblock assembly are released.

[0048] More particularly, the monoblock assembly also comprises at least a second intermediate mass 305 and a vertical movement table 31.

[0049] As described above, the technology used in manufacturing enables two separate blades to be obtained at the height of the silicon wafer, which advantageously acts on the torsional flexibility of the table without softening the table for movement. Also, the oscillator mechanism 100 can thus advantageously comprise at least two stacked basic monoblock assemblies, each basic monoblock assembly grouping together a certain level of anchor block 30, and / or the base of at least one inertial element 2, and / or the flexible pivot 200, and / or the flexible suspension 300, and / or the first intermediate mass 303, and / or the lateral movement table 32, and / or the frangible element 319. Each basic monoblock assembly can be joined to at least one other basic monoblock assembly by adhesion, by mechanical bonding, or in the case of a silicon conversion by growth of SiO2, for example.

[0050] More specifically, such a basic monoblock assembly also comprises at least one level of a second intermediate mass 305 and / or a vertical movement table 31.

[0051] According to the invention, a method 40 for adjusting a clock oscillator mechanism is used to avoid large secondary vibrations in a plane perpendicular to the XY plane.

[0052] As shown in FIG. 4, the method 40 includes a first step 41 of measuring a reference oscillation frequency of the inertial element 2 centered on the Z direction in the XY plane. For this purpose, the number of oscillations per second of the inertial element 2 is measured. For example, a measuring method using a laser system known to those skilled in the art is used.

[0053] In a second step 42, the secondary oscillation frequency of the inertial element 2 is measured in a plane substantially perpendicular to the XY plane. For example, the oscillation frequency of the inertial element 2 is measured centered on the X direction in the YZ plane or centered on the Y direction in the XZ plane. Preferably, the secondary oscillation frequency is measured centered on the X and Y directions in both the XZ and YZ planes.

[0054] The third step 43 consists of comparing the secondary oscillation frequency with the reference oscillation frequency. More specifically, it is checked whether the secondary oscillation frequency has a value substantially different from a multiple of the reference oscillation frequency. If the secondary oscillation frequency has a value substantially different from a multiple of the reference oscillation frequency, there is no need to change or replace the flexible suspension 300.

[0055] On the other hand, if the secondary oscillation frequency has a value close to or substantially equal to a multiple of the reference oscillation frequency, the method 40 includes a fourth step 44. The fourth step 44 consists of adapting the flexible suspension 300 or replacing the flexible suspension 300 with another flexible suspension so that it has a different geometric shape.

[0056] Due to this new geometric shape, the secondary vibration frequency changes so that a secondary vibration frequency that is substantially different from a multiple of the reference vibration frequency can be selected.

[0057] Preferably, in the fourth step, the same reference vibration frequency as that measured in the first step is maintained. In other words, only the secondary vibration frequency is changed by the modification or replacement of the flexible suspension, and the reference frequency remains unchanged.

[0058] Preferably, in the case of replacement, the flexible suspension 300 is replaced with another flexible suspension whose vibration characteristics, particularly the frequency of the secondary vibration, are already known.

[0059] Thus, the method 40 can include a preliminary step 39 of measuring the reference frequency and the secondary vibration frequency of a plurality of flexible suspensions having different configurations or geometric shapes. The flexible suspensions are classified, for example, according to their vibration characteristics, particularly according to their secondary vibration frequencies.

[0060] The method 40 can also include a fifth verification step 45 of measuring the secondary vibration frequency after the flexible suspension 300 has been adapted or replaced, and verifying that a value other than a multiple of the reference vibration frequency is obtained. Thus, if necessary, the flexible suspension 300 can be modified or replaced again if the measured secondary vibration frequency is not satisfactory.

[0061] In a variant of adapting the flexible suspension 300, the geometric shape of the flexible suspension 300 is changed, for example, by acting on a flexible blade or a flexible rod.

[0062] In the first embodiment, the fourth step consists of replacing or adapting the flexible suspension 300 by changing the number of the lateral flexible blades or rods 320 and / or the longitudinal flexible blades or rods 310. Each moving table 31, 32 can have more or fewer flexible blades or rods 310, 320 than the original configuration of the flexible suspension 300.

[0063] When the secondary vibration frequency is in the XZ plane, the number of blades of the lateral moving table 32 or the lateral flexible rods 320 is changed. When the secondary vibration frequency is in the YZ plane, the number of blades of the longitudinal moving table 31 or the longitudinal flexible rods 310 is changed.

[0064] FIG. 5 shows a flexible suspension 300 provided with a longitudinal moving table 31 having six longitudinal flexible blades or rods 310 between the anchor block 30 and the second intermediate mass 305. The flexible suspension 300 is also provided with a lateral moving table 32 having six lateral flexible blades or rods 320 between the first intermediate mass 303 and the second intermediate mass 305. Thus, each moving table 31, 32 is provided with one or two flexible blades or rods 310, 320 in addition to the original flexible suspension shown in FIG. 3.

[0065] A second method of performing the fourth step 44 is to replace or adapt the flexible suspension 300 by changing the stiffness of the longitudinal flexible blades or rods 310 or the lateral flexible blades or rods 320 of the flexible suspension 300.

[0066] For example, the thickness of the vertical flexible blade or rod 310 or the horizontal flexible blade or rod 320 can be adapted to change their rigidity, or the length of the vertical flexible blade or rod 310 or the horizontal flexible blade or rod 320 can be adapted to change their rigidity. In FIG. 6, the flexible blades or rods 310, 320 of the flexible suspension 300 are thicker than the flexible blades of the original flexible suspension.

[0067] In a third embodiment, the fourth step 44 consists in increasing the distance between at least two vertical flexible blades or rods 310 and / or horizontal flexible blades or rods 320 of the vertical movement table 31 and / or the horizontal movement table 32 of the flexible suspension 300. By moving the two flexible blades or rods 310, 320 away from each other, the secondary vibration frequency is changed.

[0068] For example, in FIG. 7, the flexible suspension 300 comprises two groups of flexible blades or rods 310, 320 that are separated from each other for each of the vertical movement table 31 or the horizontal movement table 32. The first three slats or rods are arranged at an equal first distance from each other, and the last three slats are arranged at the same first distance from each other.

[0069] To separate the two groups of blades, the third flexible blade and the fourth flexible blade are each separated by a second distance d_X and / or d_y that is greater than the first distance. Other configurations of the flexible suspension 300 are of course possible. For example, the distance between all the blades is equal, but is a greater or smaller distance than the original configuration.

[0070] Regardless of the design, these adaptations or replacements change the secondary vibration frequency so that it deviates from a value that is a multiple of the reference vibration frequency of the inertia elements in the XY plane.

[0071] Of course, the present invention is not limited to the embodiments described with reference to the drawings, and modifications can be assumed without departing from the scope of the present invention.

Claims

1. A method (40) for adjusting an oscillator mechanism (100) for a timepiece, said oscillator mechanism (100) comprising a structure (1) and an anchor block (30), from which at least one inertial element (2) is suspended and configured to oscillate with a first rotational degree of freedom RZ about a pivot axis (D) extending in a Z direction, said inertial element (2) being subjected to a restoring force exerted by a flexible pivot (200) comprising a plurality of substantially longitudinal elastic blades (3), each elastic blade being fixed at a first end to said anchor block (30) and at a second end to said inertial element (2), each elastic blade (3) being essentially deformable in an XY plane perpendicular to said Z direction, said anchor block (30) being suspended from said structure (1) by a flexible suspension (300) configured to allow movement of said anchor block (30), said adjustment method comprising: a first step (41) of measuring a normal vibration frequency of the inertial element (2) about the Z direction in the XY plane; a second step (42) of measuring at least one secondary vibration frequency of the inertial element (2) centered in the X direction in the YZ plane or at least one secondary vibration frequency of the inertial element (2) centered in the Y direction in the XZ plane; a third step (43) of comparing the secondary vibration frequency with the reference vibration frequency to verify that the secondary vibration frequency has a value substantially different from a multiple of the reference vibration frequency; if said secondary vibration frequency has a value close to or substantially equal to a multiple of said reference vibration frequency, a fourth step (44) of adapting said flexible suspension (300) or replacing said flexible suspension (300) with another flexible suspension in order to modify the configuration of said flexible suspension (300) so that said secondary vibration frequency is substantially different from a multiple of said reference vibration frequency; An adjustment method comprising:

2. 2. The method of claim 1, wherein the flexible suspension (300) comprises a lateral movement table (32) with flexible guides between the anchor block (30) and a first intermediate mass (303) fixed to the structure (1) directly or by means of a plate (301) flexible in the Z direction, the lateral movement table (32) comprising at least two lateral flexible blades or rods (320) extending symmetrically about a lateral axis (D2) intersecting the pivot axis (D) in the X direction, and wherein the secondary vibration frequency measured in the second step (42) is centered about the Y direction in the XZ plane.

3. 3. The method of claim 2, wherein said fourth step (44) consists in replacing or adapting said flexible suspension (300) by changing the number of laterally flexible blades or rods (320) of said lateral movement table (32).

4. 3. The adjustment method according to claim 2, characterized in that said fourth step (44) consists in replacing or adapting said flexible suspension (300) by modifying the stiffness of laterally flexible blades or rods (320) of said lateral movement table (32).

5. 5. The method of claim 4, wherein the stiffness of the laterally flexible blades or rods (320) of the lateral movement table (32) is changed by changing a thickness or a length of the laterally flexible blades or rods (320).

6. 3. The adjustment method according to claim 2, characterized in that the fourth step (44) consists in replacing or adapting the flexible suspension (300) by increasing the distance (d_y) between at least two laterally flexible blades or rods (320) of the lateral movement table (32) or between all laterally flexible blades or rods (320) of the lateral movement table (32).

7. 2. The adjustment method according to claim 1, characterized in that the flexible suspension (300) comprises a longitudinal movement table (31) with a flexible guide between the anchor block (30) and a second intermediate mass (305), the longitudinal movement table (31) comprises at least two longitudinal flexible blades or rods (310) extending symmetrically about a longitudinal axis (D1) intersecting the pivot axis (D) in the Y direction, and the secondary vibration frequency measured in the second step (42) is centered about the X direction in the YZ plane.

8. 8. The adjusting method according to claim 7, wherein said fourth step (44) consists in replacing or adapting said flexible suspension (300) by changing the number of longitudinally flexible blades or rods (310) of said longitudinally moving table (31).

9. 8. The adjusting method according to claim 7, wherein said fourth step (44) consists in replacing or adapting said flexible suspension (300) by modifying the stiffness of the longitudinally flexible blades or rods (310) of said longitudinally moving table (31).

10. The adjusting method according to claim 9, characterized in that the stiffness of the longitudinally flexible blades or rods (310) of the longitudinal moving table (31) is changed by changing the thickness or length of the longitudinally flexible blades or rods (310).

11. 8. The adjusting method according to claim 7, characterized in that said fourth step (44) consists in replacing or adapting said flexible suspensions (300) by increasing the distance (d_X) between at least two or all longitudinally flexible blades or rods (310) of said longitudinal movement table (31).

12. 2. Adjustment method according to claim 1, characterized in that in the fourth step (44) the same reference vibration frequency is maintained as that measured in the first step (41).

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