Clockwork oscillator with flexible guides and wide angled track

Description

Scope of the invention

[0001] The invention relates to a mechanical clockwork oscillator, comprising between a rigid support element and a solid inertial element, a flexible guide with at least two first flexible blades which support said solid inertial element and are arranged to return it to a rest position, said solid inertial element being arranged to oscillate angularly about a plane of oscillation around said rest position, said first two flexible blades not touching and their projections on said plane of oscillation crossing, in the rest position, at a crossing point, in the immediate vicinity of which or through which passes the axis of rotation of said solid inertial element perpendicular to said plane of oscillation, and the fixed ends of said first flexible blades with said rigid support element and said solid inertial element defining at least two blade directions parallel to said plane of oscillation.

[0002] The invention also relates to a clockwork movement comprising at least one such mechanical oscillator.

[0003] The invention also relates to a watch incorporating such a clockwork movement.

[0004] The invention relates to the field of mechanical watch oscillators comprising flexible blade guides ensuring the functions of holding and returning moving elements. Background of the invention

[0005] The use of flexible guides, particularly those with flexible blades, in mechanical watch oscillators is made possible by manufacturing processes, such as MEMS, LIGA, or similar technologies, of micromachinable materials, such as silicon and its oxides. These processes enable highly reproducible production of components that exhibit consistent elastic characteristics over time and high insensitivity to external agents such as temperature and humidity. Flexible-guided pivots, such as those described in applications EP3035126A1 or EP3206089A1 by the same applicant, can, in particular, replace the pivot of a conventional balance wheel, as well as the balance spring typically associated with it. Eliminating pivot friction substantially improves the quality factor of an oscillator.However, flexible guide pivots generally have a small angular stroke, on the order of 10° to 20°, which is very small compared to the usual amplitude of 300° of a balance wheel and hairspring, and which does not allow their direct combination with classic escapement mechanisms, and in particular with common stops such as a Swiss lever or similar, which require a large angular stroke to ensure their proper functioning.

[0006] At the Chronometry Congress in Montreux, Switzerland, on September 28 and 29, 2016, MH Kahrobaiyan's team addressed the increase of this angular stroke in the article "Gravity insensitive flexure pivots for watch oscillators", and it appears that the -complex- solution envisaged is not isochronous.

[0007] Document EP3035127A1 in the name of the same applicant SWATCH GROUP RESEARCH & DEVELOPMENT Ltd describes a clockwork oscillator comprising a time base with at least one resonator consisting of a tuning fork which has at least two oscillating moving parts, said moving parts being fixed to a linking element, which comprises said oscillator, by flexible elements whose geometry determines a virtual pivot axis of determined position relative to said linking element, around which virtual pivot axis oscillates said respective moving part, whose center of mass coincides in rest position with said respective virtual pivot axis.For at least one of said moving parts, said flexible elements consist of crossed elastic blades extending at a distance from each other in two parallel planes, and whose projections of directions onto one of said parallel planes intersect at said virtual pivot axis of said moving part considered.

[0008] The US3628781A patent in the name of GRIB describes a tuning fork, in the form of a double cantilever structure, for permitting an accentuated rotational movement of a pair of movable elements, relative to a fixed reference plane comprising a first elastically deformable body having at least two similar elastically elongated flexible parts, the ends of each of said flexible parts being respectively attached to enlarged rigid parts of said element, the first of said rigid parts being fixed to define a reference plane and the second being elastically supported to have an accentuated rotational movement relative to the first, a second elastically deformable body substantially identical to the first elastically deformable body,and means for rigidly fixing the first of said respective rigid parts of said elastically deformable bodies in spaced relation to provide a tuning fork structure in which each of the tuning fork's teeth comprises the free end of one of said elastically deformable bodies.

[0009] Document EP3324247A1, filed by the same applicant, SWATCH GROUP RESEARCH & DEVELOPMENT Ltd, describes a blade resonator for a mechanical watch movement, arranged to be fixed to a movement plate or to constitute a plate. The resonator comprises a fixed structure, arranged to be fixed to the plate or to constitute the plate, and relative to which fixed structure at least one inertial element is arranged to vibrate and / or oscillate. The resonator comprises at least one elastic blade extending between, at a first end, a first anchorage arranged at the level of the fixed structure and at a second end, a second anchorage arranged at the level of at least one inertial element. The blade is arranged to vibrate essentially in a principal plane. This blade provides guidance for the inertial element in the principal plane.For the shock protection of the blades it comprises, the resonator includes at least, at the level of the first anchorage and / or at the level of the second anchorage, at least one planar shock-absorbing device arranged to protect each blade from breakage in the event of an impact, this planar shock-absorbing device comprising at least a first flexible prestressed element with a prestressing force in the principal plane adjusted to a predetermined safety force value.

[0010] Document EP2998800A2, issued on behalf of Patek Philippe, describes a flexible pivot watch component comprising a first monolithic part defining a first rigid section and a second rigid section connected by at least one first elastic leaf, and a second monolithic part defining a third rigid section and a fourth rigid section connected by at least one second elastic leaf. The first and second monolithic parts are assembled such that the first and third rigid sections are fixed to each other, and the second and fourth rigid sections are fixed to each other. The at least one first elastic leaf and the at least one second elastic leaf intersect without contact and define a virtual axis of rotation for the second and fourth rigid sections, relative to the first and third rigid sections.This component includes a bearing, attached to the second and fourth rigid parts, and intended to guide the rotation of a moving element around an axis distinct from the virtual axis of rotation and substantially parallel to the latter.

[0011] Document EP3130966A1, issued on behalf of ETA Manufacture Horlogère Suisse, describes a mechanical watch movement comprising at least one mainspring barrel, a set of gear wheels driven at one end by the barrel, and a local oscillator escapement mechanism with a resonator in the form of a balance wheel and hairspring, and a feedback system for the watch movement. The escapement mechanism is driven at the other end of the gear wheel assembly. The feedback system includes at least one precise reference oscillator, combined with a rate comparator to compare the rate of the two oscillators, and a mechanism for adjusting the local oscillator's resonator to slow down or speed up the resonator based on a result of the comparison in the rate comparator.

[0012] Document CH709536A2, issued on behalf of ETA Manufacture Horlogère Suisse, describes a clockwork regulating mechanism comprising, mounted movably, at least pivotally, relative to a plate, an escape wheel arranged to receive a driving torque via a gear train, and a first oscillator comprising a first rigid structure connected to said plate by first elastic return means. This regulating mechanism comprises a second oscillator comprising a second rigid structure connected to said first rigid structure by second elastic return means, and which includes guiding means arranged to cooperate with complementary guiding means of said escape wheel, synchronizing said first oscillator and said second oscillator with said gear train.

[0013] Patent application EP3435170A1 from the same applicant, incorporated herein by reference, describes a pivot with a large angular stroke. By using an angle between the blades of approximately 25° to 30°, and a crossing point located at approximately 45% of their length, it is possible to simultaneously obtain good isochronism and insensitivity to position over a large angular stroke (up to 40° or more). In order to maximize the angular stroke while maintaining good out-of-plane stiffness, the blades tend to be thinner while their height is increased. The use of a large aspect ratio, i.e., the ratio of the blade height to its thickness, is theoretically advantageous, but in practice, anticlastic bending phenomena are often encountered, which impair the properties. Summary of the invention

[0014] The invention aims to develop a mechanical oscillator with flexible guides, whose angular stroke is compatible with existing escapement mechanisms, and whose flexible guides behave regularly regardless of their deformation.

[0015] This resonator with flexible rotational guidance must possess the following properties: a high quality factor; a large angular stroke; good isochronism; high insensitivity to positions in space.

[0016] Considering the specific case of a flexible guide with crossed blades projected onto a plane parallel to the plane of oscillation, where these blades connect a fixed mass and a moving mass, the possible angular travel θ of the pivot depends on the ratio X = D / L between, on the one hand, the distance D from the point where a blade is fixed to the fixed mass and the crossing point, and on the other hand, the total length L of this same blade, in its elongation, between its two opposite fixed points. The work cited above by MH Kahrobaiyan's team shows that this possible angular travel θ is, for a given pair of blades and a given apex angle α at the crossing point, here 90°, maximum for X = D / L = 0.5, and decreases rapidly as one deviates from this value, following a nearly symmetrical curve. However, such a pivot with crossed blades with X= D / L= 0.5 and α=90° is not isochronous.

[0017] The invention therefore explores the areas of favorable combinations between the values ​​of the vertex angle α at the crossing of the blades, and the values ​​of the ratio X= D / L, to obtain isochronous pivots, as well as the optimal values ​​of the aspect ratio of each of the blades.

[0018] For this purpose, the invention relates to a mechanical oscillator according to claim 1 or according to claim 2.

[0019] In particular, the invention shows that it is possible to obtain an isochronous oscillator with pivots that satisfy both inequalities: 0.15≤(X= D / L)≤0.85, and α≤60°.

[0020] Naturally, configurations with α=0° are ruled out, as the blades are no longer intersecting in projection, but parallel.

[0021] The invention also relates to a clockwork movement comprising at least one such mechanical oscillator.

[0022] The invention also relates to a watch incorporating such a clockwork movement. Brief description of the drawings

[0023] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, with reference to the attached drawings, where: there figure 1 represents, schematically and in perspective, a first variant of a mechanical oscillator, which includes a rigid, elongated support element for its attachment to a movement plate or similar, from which is suspended a massive inertial element by two separate flexible cables, crossed in projection onto the plane of oscillation of this inertial element, which cooperates with a classic escapement mechanism with a Swiss lever and standard escape wheel; the figure 2 represents, schematically and in plan view, the oscillator of the figure 1 ; there figure 3 represents, schematically, and in cross-section passing through the axis of intersection of the blades, the oscillator of the figure 1 ; there figure 4represents, in schematic form, a detail of the figure 2 showing the offset between the crossing of the blades and the projection of the resonator's center of mass, this offset detail being applicable in the same way to the different variants described below; the figure 5 is a graph, with the ratio X = D / L on the x-axis between, on the one hand, the distance D from the point of attachment of a blade to the fixed mass and the point of intersection, and on the other hand, the total length L of this same blade between its two opposite attachments, and on the y-axis the angle at the apex of intersection of the flexible blades, and which defines two curves, lower and upper, in dashed lines, which bound the suitable domain between these parameters to ensure isochronism, the curve in solid line corresponding to an advantageous value; the figure 6 represents, in a similar way to the figure 1, a second variant of the mechanical oscillator, where the rigid, elongated support element is also mobile relative to a fixed structure, and is carried by a third rigid element, via a second set of flexible blades, arranged similarly to the first flexible blades, the inertial element being again arranged to cooperate with a conventional escapement mechanism not shown; the figure 7 represents, schematically and in plan view, the oscillator of the figure 6 ; there figure 8 represents, schematically, and in cross-section passing through the axis of intersection of the blades, the oscillator of the figure 1 ; there figure 9 is a block diagram representing a watch that incorporates a movement with such a resonator; the Figure 10 represents, schematically and in perspective, a guide with crossed flexible blades in projection, between a fixed structure and an inertial element; the figure 11 represents, in a similar way to the Figure 10 , a theoretical flexible guide in which each blade has an aspect ratio greater than that of the blades of the Figure 10 ; there figure 12 represents, in a similar way to the Figure 10 , a flexible guidance system, equivalent in terms of elastic return to the theoretical guidance of the figure 11 , but comprising a greater number of blades, each of which has an aspect ratio of less than 10, in this variant two elementary blades of a first type are superimposed in a first direction, and intersect in projection two elementary blades of a second type which are also superimposed on each other and extend in a second direction; the figure 13 represents, in a similar way to the figure 12 , another flexible guide, whose four blades are staggered; the figure 14 represents, in a similar way to the figure 12, yet another flexible guide, whose four blades comprise two elementary blades of a first type in a first direction, which frame two elementary blades of a second type which are superimposed on each other and extend in a second direction; the figure 15 represents, in a similar way to the figure 12 , another flexible guide, comprising six blades stacked in threes; the figure 16 represents, in a similar way to the figure 13 , another flexible guide, whose six blades are staggered; the figure 17 represents, in a similar way to the figure 14 , another flexible guide, whose eight blades comprise a first and a second superposition of two elementary blades of a first type in a first direction, which frame four elementary blades of a second type which are superimposed on each other and extend in a second direction; the figure 18 represents, in a similar way to the figure 12, yet another flexible guide, with an unequal number of blades, the five blades of which comprise two elementary blades of a first type in a first direction, which frame three elementary blades of a second type which are superimposed on each other and extend in a second direction; the figure 19 is identical to the figure 13 , and the Figure 20 shows the decomposition of this flexible four-blade alternating guide into two subunits of two-blade pivots; the figure 21 is identical to the figure 14 , and the figure 22 shows the decomposition of this flexible four-bladed guide into two subunits of two-bladed pivots; the figure 23represents, schematically, and, brought into the same plane, the upper and lower parts of an oscillator with such flexible guidance decomposed into several subunits, in this case an upper stage and a lower stage, with translation tables interposed between the fixed support and the support of the blades towards the inertial element, these translation tables comprising flexible elastic guides along the X and Y directions of the bisectors to the projected directions of the blades; the figure 24 is similar to the figure 23 and includes an X-shaped position adjustment on a rigid lower section, so as to modify the gap between the projections of the crossings of the upper and lower blades; the figures 25 to 27 illustrate other variants of translation tables; the figure 28represents, schematically, and in side view, the upper and lower parts of an oscillator with a flexible guide decomposed into two subunits, in this case an upper stage and a lower stage, with a translation table interposed between the fixed support and the upper support of the upper blades towards the inertial element. Detailed description of preferred embodiments

[0024] The invention relates to a mechanical clockwork oscillator 100, comprising at least one rigid support element 4 fixed directly or indirectly to a plate 900, and a solid inertial element 5. This oscillator 100 comprises, between the rigid support element 4 and the solid inertial element 5, a flexible guide mechanism 200. This flexible guide mechanism comprises at least two first flexible blades 31, 32, which support the solid inertial element 5 and are arranged to return it to a rest position. This solid inertial element 5 is arranged to oscillate angularly about a plane of oscillation around this rest position.

[0025] The first two flexible blades 31 and 32 do not touch, and, in the rest position, their projections onto the plane of oscillation intersect at a crossing point P, in the immediate vicinity of which, or through which, passes the axis of rotation of the solid inertial element 5 perpendicular to the plane of oscillation. Unless otherwise stated, all the geometric elements described below are understood to be considered in the rest position of the oscillator at rest.

[0026] THE figures 1 to 4 illustrate a first variant, which is not part of the invention, with a rigid support element 4 and a massive inertial element connected by two first flexible blades 31, 32.

[0027] The fixed connections of the first flexible blades 31, 32 with the rigid support element 4 and the solid inertial element 5 define at least two blade directions DL1, DL2, which are parallel to the plane of oscillation and which make an angle at the apex α between them in projection onto the plane of oscillation.

[0028] The position of the crossing point P is defined by the ratio X = D / L, where D is the distance between the projection, onto the plane of oscillation, of one of the fixed points of the first blades 31, 32 in the first rigid support element 4 and the crossing point P, and where L is the total length of the projection, onto the plane of oscillation, of the blade 31, 32 in question. The value of the ratio D / L is between 0 and 1, and the apex angle α is less than or equal to 70°.

[0029] Advantageously, both the apex angle α is less than or equal to 60°, and, for each first flexible blade 31, 32, the fixed ratio D1 / L1, D2 / L2, is between 0.15 and 0.85, inclusive.

[0030] In particular, as seen on the figures 2 to 4 , the center of mass of the oscillator 100 in its rest position is distant from the crossing point P by a deviation ε which is between 10% and 20% of the total length L of the projection, on the plane of oscillation, of the blade 31, 32. More particularly, the deviation ε is between 12% and 18% of the total length L of the projection, on the plane of oscillation, of the blade 31, 32.

[0031] More particularly, and as illustrated in the figures, the first blades 31, 32, and their fixed parts together define a pivot 1 which, in projection onto the plane of oscillation, is symmetric with respect to an axis of symmetry AA passing through the crossing point P.

[0032] More specifically, when the pivot 1 is symmetric with respect to the axis of symmetry AA, in the rest position, in projection onto the plane of oscillation, the center of mass of the massive inertial element 5 is located on the axis of symmetry AA of the pivot 1. In projection, this center of mass may or may not coincide with the crossing point P.

[0033] More specifically, the center of mass of the massive inertial element 5 is located at a non-zero distance from the crossing point P corresponding to the axis of rotation of the massive inertial element 5, as seen on the figures 2 to 4 .

[0034] In particular, in projection onto the plane of oscillation, the center of mass of the massive inertial element 5 is located on the axis of symmetry AA of the pivot 1, and is located at a non-zero distance from the crossing point P which is between 0.1 times and 0.2 times the total length L of the projection, onto the plane of oscillation, of the blade 31, 32.

[0035] More specifically, the first blades 31 and 32 are straight blades.

[0036] More specifically, the vertex angle α is less than or equal to 50°, or is less than or equal to 40°, or is less than or equal to 35°, or is less than or equal to 30°.

[0037] More specifically, the fixed ratio D1 / L1, D2 / L2, is between 0.15 and 0.49, inclusive, or between 0.51 and 0.85, inclusive, as shown on the figure 5 .

[0038] In one variant, and more specifically according to the execution according to the figure 5, the apex angle α is less than or equal to 50°, and the fixed ratio D1 / L1, D2 / L2, is between 0.25 and 0.75, inclusive.

[0039] In one variant, and more specifically according to the execution according to the figure 5 , the apex angle α is less than or equal to 40°, and the fixed ratio D1 / L1, D2 / L2, is between 0.30 and 0.70, inclusive.

[0040] In one variant, and more specifically according to the execution according to the figure 5 , the apex angle α is less than or equal to 35°, and the fixed ratio D1 / L1, D2 / L2, is between 0.40 and 0.60, inclusive.

[0041] In an advantageous way, and as can be seen on the figure 5 The vertex angle α and the ratio X = D / L satisfy the relation: h 1 D / L < a < h 2 D / L , with, for 0.2≤X<0.5: h 1 X = 116 − 473 * X + 0.05 + 3962 * X + 0.05 3 − 6000 * X + 0.05 4 , h 2 X = 128 − 473 * X − 0.05 + 3962 * X − 0.05 3 − 6000 * X − 0.05 4 , For 0.5 < X ≤ 0.8 : h 1 X = 116 − 473 * 1.05 − X + 3962 * 1.05 − X 3 − 6000 * 1.05 − X 4 , h 2 X = 128 − 473 * 0.95 − X + 3962 * 0.95 − X 3 − 6000 * 0.95 − X 4 .

[0042] More specifically, and particularly in the non-limiting embodiment illustrated by the figures, the first flexible blades 31 and 32 have the same length L, and the same distance D.

[0043] More specifically, between their insets, these first flexible blades 31 and 32 are identical.

[0044] THE figures 6 to 8 illustrate a second variant of mechanical oscillator 100, which is not part of the invention, where the rigid support element 4 is also mobile, directly or indirectly relative to a fixed structure comprising this oscillator 100, and is carried by a third rigid element 6, by means of two second flexible blades 33, 34, arranged in a similar way to the first flexible blades 31, 32.

[0045] More particularly, in the non-limiting embodiment illustrated by the figures, the projections of the first flexible blades 31, 32, and of the second flexible blades 33, 34, on the plane of oscillation cross at the same crossing point P.

[0046] In another particular form of embodiment not illustrated, in rest position, in projection onto the plane of oscillation, the projections of the first flexible blades 31, 32, and of the second flexible blades 33, 34, onto the plane of oscillation intersect at two distinct points both located on the axis of symmetry AA of the pivot 1, when the pivot 1 is symmetric with respect to the axis of symmetry AA.

[0047] More specifically, the fixed connections of the second flexible blades 33, 34, with the rigid support element 4 and the third rigid element 6, define two blade directions parallel to the plane of oscillation and making between them, in projection onto the plane of oscillation, a vertex angle of the same bisector as the vertex angle α of the first flexible blades 31, 32. More specifically still, these two directions of the second flexible blades 33, 34, have the same vertex angle α as the first flexible blades 31, 32.

[0048] In particular, the second flexible blades 33, 34 are identical to the first flexible blades 31, 32, as in the non-limiting example of the figures.

[0049] More specifically, when pivot 1 is symmetric with respect to the axis of symmetry AA, in rest position, in projection onto the plane of oscillation, the center of mass of the massive inertial element 5 is located on the axis of symmetry AA of pivot 1.

[0050] Similarly and specifically, when the pivot 1 is symmetric with respect to the axis of symmetry AA, in the rest position, the center of mass of the rigid support element 4 is located, in projection onto the plane of oscillation, on the axis of symmetry AA of the pivot 1.

[0051] In a particular variant, when the pivot 1 is symmetric with respect to the axis of symmetry AA, in the rest position, in projection onto the plane of oscillation, both the center of mass of the massive inertial element 5 and the center of mass of the rigid support element 4 are located on the axis of symmetry AA of the pivot 1. More particularly still, the projections of the center of mass of the massive inertial element 5 and of the center of mass of the rigid support element 4, onto the axis of symmetry AA of the pivot 1, are coincident.

[0052] A particular configuration illustrated in the figures for such superimposed pivots is that in which the projections of the first flexible blades 31, 32, and the second flexible blades 33, 34, onto the plane of oscillation intersect at the same crossing point P, which also corresponds to the projection of the center of mass of the solid inertial element 5, or at least to the closest possible point to it. More specifically, this same point also corresponds to the projection of the center of mass of the rigid support element 4. Even more specifically, this same point also corresponds to the projection of the center of mass of the entire oscillator 100.

[0053] In a particular variant of this superimposed pivot configuration, when pivot 1 is symmetrical with respect to the axis of symmetry AA, in its rest position, projected onto the plane of oscillation, the center of mass of the massive inertial element 5 is located on the axis of symmetry AA of pivot 1, and at a non-zero distance from the crossing point corresponding to the axis of rotation of the massive inertial element 5. This non-zero distance is between 0.1 and 0.2 times the total length L of the projection, onto the plane of oscillation, of the blade 33, 34, with a deviation similar to the deviation ε of the figures 2 to 4 .

[0054] In a similar and particular way, when the pivot 1 is symmetric with respect to the axis of symmetry AA, the center of mass of the massive inertial element 5 is located, in projection onto the plane of oscillation, on the axis of symmetry AA of the pivot 1 and at a non-zero distance from the crossing point corresponding to the axis of rotation of the rigid support element 4, which non-zero distance is between 0.1 times and 0.2 times the total length L of the projection, on the plane of oscillation, of the blade 31, 32.

[0055] In a similar and particular way, when the pivot 1 is symmetric with respect to the axis of symmetry AA, the center of mass of the rigid support element 4 is located, in projection onto the plane of oscillation, on the axis of symmetry AA of the pivot 1 and at a non-zero distance from the crossing point P corresponding to the axis of rotation of the massive inertial element 5. In particular, this non-zero distance is between 0.1 times and 0.2 times the total length L of the projection, on the plane of oscillation, of the blade 33, 34.

[0056] Similarly and in particular, when the pivot 1 is symmetric with respect to the axis of symmetry AA, the center of mass of the rigid support element 4 is located, in projection onto the plane of oscillation, on the axis of symmetry AA of the pivot 1 and at a non-zero distance from the crossing point corresponding to the axis of rotation of the rigid support element 4, which non-zero distance is between 0.1 times and 0.2 times the total length L of the projection, on the plane of oscillation, of the blade 31, 32.

[0057] In a similar and particular way, the center of mass of the rigid support element 4 is located on the axis of symmetry AA of the pivot 1 and at the non-zero distance from the crossing point P which is between 0.1 times and 0.2 times the total length L of the projection, on the plane of oscillation, of the blade 33, 34.

[0058] More specifically, and as can be seen in the variant of the figures, when the pivot 1 is symmetric with respect to the axis of symmetry AA, in projection onto the plane of oscillation, the center of mass of the oscillator 100 in its rest position is located on the axis of symmetry AA.

[0059] More specifically, the massive inertial element 5 is elongated along the direction of the axis of symmetry AA of the pivot 1, when the pivot 1 is symmetrical with respect to the axis of symmetry AA. This is, for example, the case of figures 1 to 4 where the inertial element 5 comprises a base on which is fixed a traditional long-armed rocker arm fitted with sections of serge or circular-arc weights. The objective is to minimize the influence of external angular accelerations around the axis of symmetry of the pivot, because the blades have low rotational rigidity around this axis due to the small angle α.

[0060] The invention lends itself well to a monolithic embodiment of the blades and the solid components they join, made of micromachinable or at least partially amorphous material, using a MEMS, LIGA, or similar manufacturing process. In particular, in a silicon embodiment, the oscillator 100 is advantageously thermally compensated by adding silicon dioxide to flexible silicon blades. In one variant, the blades can be assembled, for example, embedded in grooves, or otherwise.

[0061] When you have two pivots in series, as in the case of figures 6 to 9The center of mass can be placed on the axis of rotation if the arrangement is chosen so that parasitic displacements cancel each other out. This is an advantageous but not limiting option. However, it should be noted that such an arrangement is not necessary, and such an oscillator operates with two pivots in series without positioning the center of mass on the axis of rotation. Of course, even though the illustrated designs correspond to specific geometric configurations of alignment or symmetry, it is understood that it is also possible to stack two different pivots, or pivots with different crossing points, or pivots with non-aligned centers of mass, or even to use a greater number of sets of blades in series, with intermediate masses, to further increase the amplitude of the pendulum.

[0062] The illustrated variants all have coplanar pivot axes, blade crossings, and centers of mass, which is an advantageous, but not limiting, special case.

[0063] It is understood that it is thus possible to obtain a large angular stroke: in any case greater than 30°, it can even reach 50° or even 60°, which makes it compatible in combination with all the usual mechanical escapements, Swiss lever, detent, coaxial, or other.

[0064] The challenge, once again, is to determine a practical solution that is equivalent to the theoretical use of a high value for the aspect ratio of the blades.

[0065] To achieve this, it is advantageous to subdivide the plates lengthwise, replacing a single plate with a plurality of elementary plates whose overall behavior is equivalent, and where each of the elementary plates has an aspect ratio limited to a threshold value. This reduces the aspect ratio of each elementary plate relative to a single reference plate, thus restoring the optimum of isochronism and insensitivity to position.

[0066] Each blade 31, 32 has an aspect ratio RA = H / E, where H is the height of the blade 31,32, perpendicular to both the plane of oscillation and the elongation of the blade 31, 32, along the length L, and where E is the thickness of the blade 31, 32, in the plane of oscillation and perpendicular to the elongation of the blade 31, 32, along the length L.

[0067] Preferably, the aspect ratio RA = H / E is less than 10 for each blade 31, 32. More specifically, this aspect ratio is less than 8. And the total number of flexible blades 31, 32 is strictly greater than two.

[0068] More specifically, the oscillator 100 comprises a first number N1 of first blades called primary blades 31 extending along a first blade direction DL1, and a second number N2 of first secondary blades 32 extending along a second blade direction DL2, the first number N1 and the second number N2 each being greater than or equal to two.

[0069] More specifically, the first number N1 is equal to the second number N2.

[0070] More specifically, the oscillator 100 comprises at least one pair consisting of a primary blade 31 extending along a first blade direction DL1, and a secondary blade 32 extending along a second blade direction DL2. And, in each pair, the primary blade 31 is identical to the secondary blade 32 except for the orientation.

[0071] In a particular variant, the oscillator 100 consists only of pairs, each formed of a primary blade 31 extending along a first blade direction DL1, and a secondary blade 32 extending along a second blade direction DL2, and, in each pair, the primary blade 31 is identical to the secondary blade 32 except for the orientation.

[0072] In another variant, the oscillator 100 comprises at least one group of blades consisting of a primary blade 31 extending along a first blade direction DL1, and a plurality of secondary blades 32 extending along a second blade direction DL2. And, in this case, in each group of blades, the elastic behavior of the primary blade 31 is identical to the elastic behavior resulting from the summation of the plurality of secondary blades 32, up to the orientation.

[0073] It is also worth noting that, while the behavior of a flexible blade depends on its aspect ratio (RA), it also depends on the value of the imparted curvature. Its deformation depends both on the aspect ratio and the local value of the radius of curvature, particularly at the fixed end. This is why a symmetrical arrangement of the blades in planar projection is preferred.

[0074] The invention also relates to a 1000 clock movement comprising at least one such mechanical oscillator 100.

[0075] The invention also relates to a 2000 watch comprising at least one such 1000 watch movement.

[0076] A suitable manufacturing process consists of performing the following operations for the different types of pivots below: For a pivot type AABB: a. use a substrate with at least four layers, resulting for example but not limited to the assembly of two SOI wafers; b. etch by the "DRIE" etching process on the front side to obtain AA, including etching the two layers in one piece; c. etch by the "DRIE" etching process on the back side to obtain BB, including etching the two layers in one piece; d. perform the partial separation of the four layers by etching the buried oxide.

[0077] The high precision of the "DRIE" process, or Deep Reactive Ion Etching (DRIE), guarantees excellent positioning and alignment accuracy, less than or equal to 5 micrometers, thanks to optical alignment, ensuring very good face-to-face alignment. Naturally, equivalent processes can be implemented depending on the material chosen.

[0078] It is possible to implement substrates with a greater number of layers, including a substrate with six available layers, for example by assembling two DSOIs, to obtain an AAABBB type structure.

[0079] One alternative method for obtaining the same type of AABB pivot is to: a. Use two standard two-layer SOI substrates; b. Etch the first substrate using the "DRIE" etching process, on the front face to obtain A, and on the back face to obtain A; c. Etch the second substrate using the "DRIE" etching process, on the front face to obtain B, and on the back face to obtain B; alternatively, on both substrates, etch both layers simultaneously, without performing front and back face etching; d. Perform the "wafer-to-wafer" bonding of the two substrates or the "piece-to-piece" bonding of the individual components to obtain AABB. Proper alignment of the geometries is then linked to the specification of the "wafer-to-wafer" bonding machine or the "piece-to-piece" process, as is well known to those skilled in the art.

[0080] For a pivot type ABAB: a. Use two standard two-layer SOI substrates; b. Etch the first substrate using a DRIE etching process, on the front face to obtain A, and on the back face to obtain B; c. Etch the second substrate using a DRIE etching process, on the front face to obtain A, and on the back face to obtain B; d. Perform wafer-to-wafer bonding of the two substrates or piece-to-piece bonding of the individual components to obtain ABAB. As before, proper alignment of the geometries is linked to the specification of the wafer-to-wafer bonding machine or the piece-to-piece process.

[0081] Many other process variations can be implemented, depending on the number of blades and the equipment available.

[0082] Standard DRIE (Direct Rendering Etching) methods for manufacturing silicon do not yet allow for the easy fabrication of a monolithic pivot with more than two distinct levels. Therefore, it is easier to manufacture separate parts that are then assembled. However, sensitivity to assembly errors requires sub-micrometer precision to achieve optimal isochronism and / or position insensitivity. To overcome this problem, a manufacturing strategy, described below, is necessary.

[0083] The first step involves assembling two blades with different orientations with high precision. The invention proposes to divide the flexible guide, or pivot, into subunits composed of two-blade pivots, for example, an upper subunit and a lower subunit, in the case of a flexible guide with four blades, as shown in the illustration. figure 19, with four alternating blades, which are broken down into two subunits of two-bladed pivots. The Figures 21 and 22 illustrate a similar breakdown in the case of framed blades rather than alternating blades. Each subunit is manufactured by two-level DRIE etching (SOI wafer attacked from above and below) to ensure sufficient alignment accuracy.

[0084] The upper subunit is then assembled to the lower subunit.

[0085] This assembly can be carried out by any traditional method: alignment doweling and screwing, or gluing, or "wafer fusion bonding", or welding, or brazing, or any other method known to a person skilled in the art.

[0086] The assembly defect manifests as a small offset Δ between the rotation axes of the upper and lower subunits. Consequently, the rotational movement of the resonator dictated by the upper subunit is not in agreement with the rotational movement dictated by the lower subunit.

[0087] To prevent this discrepancy from causing excessive stress, the mechanism includes at least one translation table, whose free movement allows it to absorb the misalignment between the two rotations around distinct axes. At least one of the translation tables must be sufficiently flexible so that the misalignment in movement does not degrade isochronism. In the case where two identical translation tables are introduced, as shown in the figure 23They must be sufficiently flexible so that the movement misalignment does not degrade the isochronism, and sufficiently rigid so that the pivot position is precisely determined. Calculations show that these conditions are not contradictory if the offset between the axes of rotation is less than 10 micrometers, which is achievable with traditional assembly. Naturally, the precision of such an assembly can be improved with additional engravings, such as mortise and tenon joints, or with a plurality of mortise and tenon joints forming a non-zero angle with each other, or any other arrangement known in precision mechanics.

[0088] More specifically, as can be seen in the figures, the flexible guide mechanism 200 comprises, superimposed one on top of the other, at least one upper stage 28 and at least one lower stage 29.

[0089] The upper subunit comprises an upper stage 28, which includes, between an upper support 48 and an upper inertial element 58, at least one upper primary blade 318 extending along a first upper blade direction DL1S and an upper secondary blade 328 extending along a second upper blade direction DL2S, crossed in projection at an upper crossing point PS.

[0090] The lower subunit comprises a lower stage 29, which includes, between a lower support 49 and a lower inertial element 59, at least one lower primary blade 319 extending along a first lower blade direction DL1I and a lower secondary blade 329 extending along a second lower blade direction DL2I crossed in projection at a lower crossing point PI, at rest distant from the upper crossing point PS by a gap Δ.

[0091] And at least the upper stage 28 or the lower stage 29 comprises, between the plate 900 and the upper support 48, or respectively the lower support 49, an upper translation table 308, or respectively a lower translation table 309, which comprises at least one elastic link which permits translation along one or two axes of freedom in the plane of oscillation, and whose translational stiffness along these two axes is less than that of each flexible blade 31, 32, 333, 34, 318, 319, 328, 329, which comprises the flexible guide mechanism 200.

[0092] Note that this elastic connection does not allow rotations around an axis parallel to that of the resonator.

[0093] Note that it is not necessary for the upper directions DL1S and DL2S of the upper floor 28 to be identical to the lower directions DL1I and DL2I of the lower floor 29. Preferably, they have the same bisectors.

[0094] More specifically, the point P through which the axis of rotation of the inertial element 5 passes is located between the upper crossing point PS and the lower crossing point PI, exactly in the middle if the flexible guide mechanism 200 has two identical upper and lower translation tables 308 and 309. In an alternative, this point P is located exactly on the lower crossing point PI if the lower stage 29 does not have a translation table, or on the upper crossing point PS if the upper stage 28 does not have a translation table.

[0095] Preferably, the oscillator 100 comprises, for each flexible guide mechanism 200 it includes, a unique solid inertial element 5. More specifically, the flexible guide mechanism 200 is unique, and the solid inertial element 5 is unique.

[0096] Naturally, the preferred configuration of translation tables 308 and 309 illustrated by the figures is not limiting.

[0097] According to the invention as defined in the attached independent claim 2, these translation tables 308 and 309 are located between the inertial element 5 and the fixed ends on the inertial element side.

[0098] If we define X and Y as the axes of the angle bisectors of the projections of the flexible blades onto a common parallel plane, the combination of the tables in translation along the X and Y axes must be more flexible than the flexible pivot along the same axes. This rule holds true regardless of the number of stages; the cumulative effect of combining all the tables in translation along the X and Y axes must be more flexible than the flexible pivot. The elastic connection of the upper translation table 308, and respectively of the lower translation table 309, along one or two axes of freedom in the plane of oscillation, is therefore preferably an elastic connection along these X and Y axes.

[0099] The additional elastic energy stored in the translation table(s), resulting from the misalignment of motion, adds to the main energy storage of the pivot and tends to disrupt isochronism, unless the value of the additional storage is much smaller than that of the main storage. This is why the elastic joints in the translation tables must be much more flexible than those of the flexible pivot.

[0100] According to the invention, the upper stage 28 and the lower stage 29 each comprise, between the plate 900 and the upper support 48, and respectively the lower support 49, an upper translation table 308, and respectively a lower translation table 309, comprising at least one elastic connection along one or two axes of freedom in the plane of oscillation, and whose stiffness is less than that of each flexible blade.

[0101] The translation tables are not necessarily identical to each other.

[0102] One variant involves using two different translation tables, the first being flexible so that the movement disagreement does not degrade the isochronism, and the second being rigid to ensure the positioning of the pivot.

[0103] In another variant, one stage may include a translation table, and the other stage may have a rigid attachment. The upper inertial element 58 and the lower inertial element 59 constitute all or part of the solid inertial element 5 and are rigidly connected, directly or indirectly, to each other. The upper support 48 and the lower support 49 are connected, as the case may be, directly or via an upper translation table 308 or a lower translation table 309, respectively, to an upper rigid part 480 or a lower rigid part 490, respectively, which are themselves rigidly connected to the rigid support element 4 or to the plate 900.

[0104] THE Figures 23 and 24They show an example of such a connection. An upper translation table 308 comprises, between the upper support 48 and an upper intermediate mass 68, first flexible elastic connections 78 extending along the X direction, and, between the upper intermediate mass 68 and the upper rigid part 480, second flexible elastic connections 88 extending along the Y direction. Similarly, a lower translation table 309 comprises, between the lower support 49 and a lower intermediate mass 69, first flexible elastic connections 79 extending along the X direction, and, between the lower intermediate mass 69 and the lower rigid part 490, second flexible elastic connections 89 extending along the Y direction.

[0105] Thus, the movement of the translation tables allows for the absorption of any potential discrepancy between the rotations of the upper and lower subunits. Furthermore, each translation table contributes to protecting the mechanism against high accelerations, such as during a fall or impact.

[0106] It is understood that the assembly as described above in the first approach makes it possible to make the added anisochronism negligible, provided that the assembly defect Δ is sufficiently small.

[0107] Conversely, one can choose to deliberately exaggerate the assembly error Δ in order to introduce controlled anisochronism, for example, to compensate for a delay in the escapement. It is then advantageous to make at least one of the mountings to the mainplate movable and adjustable, i.e., the upper support 48 and / or the lower support 49 in the case of the specific, non-limiting variant illustrated. Indeed, by adjusting the relative position of these two mountings, the rigidity of the translation tables 308, 309 is modified, which in turn allows for the adjustment of the added anisochronism. Such an adjustment can be easily achieved with a combination of a groove and an eccentric, or by any other solution known to the watchmaker.

[0108] In short, by shifting the position of at least one of the mountings on the plate, as visible on the figure 24 , it is possible to adjust the anisochronism produced by the assembly defect Δ.

[0109] This particular arrangement with at least one translation table makes it possible, in short, to guarantee the alignment between the upper and lower floors, and to avoid the great stresses that the blades would undergo if the upper and lower floors did not follow the same trajectory.

[0110] Another alternative is to equip the mechanism with an upper translation table 308 and a lower translation table 309, with an upper support 48 and a lower support 49 which are no longer rigidly linked to the rigid support element 4, or to the plate 900, but which are constrained to planar movements, inverse in X and Y, by a crankshaft type connection or similar, relative to a fixed axis of the rigid support element 4, or of the plate 900. This solution has the advantage of allowing the anisochronism to be adjusted without slightly moving the axis of rotation of the resonator.

[0111] It is understood that translation tables, which constitute flexible translational guides, can be implemented in many different ways. Those skilled in the art will find examples in the following references: [1] S. Henein, Design of Flexible Guides. PPUR, [2] Larry L. Howell, Handbook of compliant mechanisms, WILEY), or [3] Zeyi Wu and Qingsong Xu, Actuators 2018. Such non-exhaustive examples are illustrated in figures 25 to 27 .

[0112] There figure 28illustrates a simplified example with a translation table with a connection by collars: the upper support 48 is linked to an intermediate element 488 suspended by a first elastic collar 880 to a second intermediate element 889 to a second collar 890 which makes the elastic connection with the lower rigid part 490, rigidly linked to the plate 900. In this example the upper inertial element 58 and the lower inertial element 59 are linked to another intermediate element 589 to form with it the solid inertial element 5.

Claims

1. A mechanical horological oscillator (100) comprising, between a first rigid support element (4) directly or indirectly fixed to a plate (900), and a solid inertial element (5), a flexible guide mechanism (200) comprising at least two first flexible blades (31; 32) which support said solid inertial element (5) and are arranged to return it to a lock position, said solid inertial element (5) being arranged to oscillate angularly in an oscillation plane about said lock position, said two first flexible blades (31; 32) not touching each other and their projections onto said oscillation plane crossing, in the lock position, at a crossing point (P), in proximity to which passes the axis of rotation of said solid inertial element (5) perpendicularly to said oscillation plane, characterised in that said flexible guide mechanism (200) comprises, overlapping each other, at least one upper level (28), which comprises, between an upper support (48) and said solid inertial element (5), at least one upper primary blade (318) extending in a first upper blade direction (DL1S) and one upper secondary blade (328) extending in a second upper blade direction (DL2S), crossed in projection at an upper crossing point (PS) defining an upper pivot, and at least one lower level (29) defining a lower pivot and which comprises, between a lower support (49) and said solid inertial element (5), at least one lower primary blade (319) extending in a first lower blade direction (DL1I) and one lower secondary blade (329) extending in a second lower blade direction (DL2I), crossed in projection at a lower crossing point (PI), the primary blades (318, 319) and secondary blades (328, 329) defining the first flexible blades (31; 32) of the flexible guide mechanism (200), characterised in that said upper level (28) and said lower level (29) each comprise, between said plate (900) and said upper support (48), and respectively said lower support (49), a translational table (308; 309) comprising at least one resilient connection along one or two axes of freedom in the oscillation plane, and whose translational stiffness is less than that of said pivot of the upper level and also than that of said pivot of said lower level, to allow a relative translation between said upper level and said lower level, in order to allow adjustment of the relative position of the two settings of said flexible blades (31; 32) on the side of said upper support (48) and of said lower support (49), and modification of the stiffness of said translational tables (308; 309) to allow adjustment of the anisochronism.

2. A mechanical horological oscillator (100) comprising, between a first rigid support element (4) directly or indirectly fixed to a plate (900), and a solid inertial element (5), a flexible guide mechanism (200) comprising at least two first flexible blades (31; 32) which support said solid inertial element (5) and are arranged to return it to a lock position, said solid inertial element (5) being arranged to oscillate angularly in an oscillation plane about said lock position, said two first flexible blades (31; 32) not touching each other and their projections onto said oscillation plane crossing, in the lock position, at a crossing point (P), in proximity to which passes the axis of rotation of said solid inertial element (5) perpendicularly to said oscillation plane, characterised in that said flexible guide mechanism (200) comprises, overlapping each other, at least one upper level (28), which comprises, between an upper support (48) and said solid inertial element (5), at least one upper primary blade (318) extending in a first upper blade direction (DL1S) and one upper secondary blade (328) extending in a second upper blade direction (DL2S), crossed in projection at an upper crossing point (PS) defining an upper pivot, and at least one lower level (29) defining a lower pivot and which comprises, between a lower support (49) and said solid inertial element (5), at least one lower primary blade (319) extending in a first lower blade direction (DL1I) and one lower secondary blade (329) extending in a second lower blade direction (DL2I), crossed in projection at a lower crossing point (PI), the primary blades (318, 319) and secondary blades (328, 329) defining the first flexible blades (31; 32) of the flexible guide mechanism (200), characterised in that it comprises, between the inertial element (5) and the setting of the lower primary blade (319), and, respectively, between the inertial element (5) and the setting of the lower secondary blade (329), a translational table (308; 309) comprising at least one resilient connection along one or two axes of freedom in the oscillation plane, and whose translational stiffness is less than that of said pivot of the upper level and also than that of said pivot of said lower level, to allow a relative translation between said upper level and said lower level, in order to allow adjustment of the relative position of the two settings of said flexible blades (31; 32) on the side of solid inertial element (5) and modification of the stiffness of said translational tables (308; 309) to allow adjustment of the anisochronism.

3. The mechanical oscillator (100) according to claim 1 or 2, characterised in that said resilient connection of said upper translational table (308) or respectively of said lower translational table (309), along one or two axes of freedom in said oscillation plane, is a resilient connection along the X and Y axes of the bissectors of the angles formed between the projections of the flexible blades of said flexible guide mechanism (200) onto a common parallel plane.

4. The mechanical oscillator (100) according to any of claims 1 to 3, characterised in that said two blade directions (DL1; DL2) parallel to said oscillation plane and forming between them, in the lock position, in projection onto said oscillation plane, a vertex angle α, the position of said crossing point (P) being defined by the ratio X= D / L, where D is the distance between the projection onto said oscillation plane of one of the settings of said first blades (31; 32) in said first rigid support element (4) and said crossing point (P), and where L is the total length of the projection, onto said oscillation plane, of said blade (31, 32), and in that the centre of mass of said oscillator (100) in its lock position, is separated from said crossing point (P) by an offset (ε), which is comprised between 12% and 18% of said total projected length L, onto said oscillation plane, of said blade (31; 32), in that the value of said ratio D / L is comprised between 0 and 1, in that said vertex angle (α) is less than or equal to 60°, and in that, for each said first flexible blade (31; 32), the setting ratio (D1 / L1; D2 / L2) is comprised between 0.15 and 0.85 inclusive.

5. The mechanical oscillator (100) according to any of claims 1 to 3, characterised in that each said blade (31; 32) has an aspect ratio RA = H / E, where H is the height of said blade (31; 32) perpendicularly both to the oscillation plane and to the elongation of said blade (31; 32) along said length L, and where E is the thickness of said blade (31; 32) in the oscillation plane and perpendicularly to the elongation of said blade (31; 32) along said length L, and in that said aspect ratio RA = H / E is less than 10 for each said blade (31; 32), and in that the total number of said flexible blades (31; 32) is strictly greater than two.

6. The mechanical oscillator (100) according to claim 5, characterised in that said oscillator (100) comprises a first number N1 of said first blades, called primary blades (31), extending in a first blade direction (DL1), and a second number N2 of said first blades called secondary blades (32) extending in a second blade direction (DL2), said first number N1 and said second number N2 each being greater than or equal to two.

7. The mechanical oscillator (100) according to claim 6, characterised in that said first number N1 is equal to said second number N2.

8. The mechanical oscillator (100) according to claim 6 or 7, characterised in that said oscillator comprises at least one pair formed of one said primary blade (31) extending in a first blade direction (DL1), and of one said secondary blade (32) extending in a second blade direction (DL2), and in that, in each pair, said primary blade (31) is identical to said secondary blade (32), except as regards orientation.

9. The mechanical oscillator (100) according to claim 8, characterised in that said oscillator comprises only said pairs each formed of one said primary blade (31) extending in a first blade direction (DL1), and of one said secondary blade (32) extending in a second blade direction (DL2), and in that, in each pair, said primary blade (31) is identical to said secondary blade (32), except as regards orientation.

10. The mechanical oscillator (100) according to claim 6 or 8 according to 6, characterised in that said oscillator comprises at least one group of blades formed of one said primary blade (31) extending in a first blade direction (DL1), and of a plurality of said secondary blades (32) extending in a second blade direction (DL2) and in that, in each said group of blades, the elastic behaviour of said primary blade (31) is identical to the elastic behaviour resulting from said plurality of secondary blades (32) except as regards orientation.

11. The mechanical horological oscillator (100) according to any of claims 1 to 10, characterised in that said two blade directions (DL1; DL2) parallel to said oscillation plane form between them, in the lock position, in projection onto said oscillation plane, a vertex angle α, the position of said crossing point (P) being defined by the ratio X= D / L, where D is the distance between the projection, onto said oscillation plane, of one of the settings of said first blades (31; 32) in said first rigid support element (4) and said crossing point (P), and L is the total length of the projection, onto said oscillation plane, of said blade (31; 32) in its elongation, and in that said setting ratio (D1 / L1; D2 / L2) is comprised between 0.15 and 0.49 inclusive, or between 0.51 and 0.85 inclusive.

12. The mechanical oscillator (100) according to claim 11, characterised in that said vertex angle (α) is less than or equal to 50°, and characterised in that said setting ratio (D1 / L1; D2 / L2) is comprised between 0.25 and 0.75 inclusive.

13. The mechanical oscillator (100) according to claim 12, characterised in that said vertex angle (α) is less than or equal to 40°, and in that said setting ratio (D1 / L1; D2 / L2) is comprised between 0.30 and 0.70 inclusive.

14. The mechanical oscillator (100) according to claim 13, characterised in that said vertex angle (α) is less than or equal to 35°, and in that said setting ratio (D1 / L1; D2 / L2) is comprised between 0.40 and 0.60 inclusive.

15. The mechanical oscillator (100) according to any of claims 11 to 14, characterised in that said vertex angle (α) is less than or equal to 30°.

16. The mechanical oscillator (100) according to any of claims 11 to 15, characterised in that said vertex angle (α) and said ratio X= D / L satisfy the relation h1(D / L) < α< h2(D / L), where, for 0.2≤X<0.5: h 1 X = 116 − 473 * X + 0.05 + 3962 * X + 0.05 3 − 6 , 000 * X + 0.05 4 , h 2 X = 128 − 473 * X − 0.05 + 3 , 962 * X − 0.05 3 − 6 , 000 * X − 0.05 4 , for 0.5 < X ≤ 0.8 : h 1 X = 116 − 473 * 1.05 − X + 3 , 962 * 1.05 − X 3 − 6 , 000 * 1.05 − X 4 , h 2 X = 128 − 473 * 0.95 − X + 3 , 962 * 0.95 − X 3 − 6 , 000 * 0.95 − X 4 .

17. The mechanical oscillator (100) according to any of claims 1 to 16, characterised in that said flexible blades are straight blades.

18. A horological movement (1000) comprising at least one mechanical oscillator (100) according to any of claims 1 to 17.

19. A watch (2000) comprising at least one horological movement (1000) according to claim 18.