CH714030A2 - Clock oscillator with flexible guides with long angular travel. - Google Patents

Abstract

The invention relates to a clockwork mechanical oscillator, comprising, between a first element (4) and a second inertial element (5), two distinct flexible blades (31; 32) recalling the inertial element (5) towards a position of resting in a plane of oscillation, the projections of these blades intersecting, in the rest position, at a point (P), through which the pivot axis of the second solid inertial element (5) passes, and the ratio of aspect height over thickness is less than 10 for each blade (31; 32), and the total number of flexible blades (31; 32) is strictly greater than two.

Description

Description

FIELD OF THE INVENTION The invention relates to a mechanical clockwork oscillator, comprising a first rigid support element, a second massive inertial element, and, between said first rigid support element and said second massive inertial element at least two first flexible blades which support said second massive inertial element and are arranged to return it to a rest position, said second massive inertial element being arranged to oscillate angularly according to a plane of oscillation around said rest position, said first two flexible blades not touching each other and their projections on said plane of oscillation intersecting, in the rest position, at a point of intersection, in the immediate vicinity of or through which passes the axis of rotation of said second massive inertial element perpendicular to said plane of oscillation , and the embedding of said first flexible blades with said first rigid support element and said second massive inertial element defining two directions of blades parallel to said plane of oscillation.

The invention also relates to a timepiece movement comprising at least one such mechanical oscillator.

The invention also relates to a watch comprising such a clockwork movement.

The invention relates to the field of mechanical watch oscillators comprising guides with flexible blades ensuring the functions of retaining and recalling moving elements.

BACKGROUND OF THE INVENTION The use of flexible guides, in particular with flexible blades, in mechanical clock oscillators, is made possible by production methods, such as “MEMS”, “LIGA” or similar, of micro-machinable materials, such as silicon and its oxides, which allow a very reproducible manufacture of components which have elastic characteristics constant over time and a great insensitivity to external agents such as temperature and humidity. Pivots with flexible guidance, as described in applications EP 1 419 039 or EP 16 155 039 from the same applicant, in particular make it possible to replace the pivot of a conventional balance, as well as the balance spring which is usually associated with it. By eliminating the friction of pivots, the quality factor of an oscillator can be substantially increased. However, the pivots with flexible guidance generally have a small angular travel, of the order of 10 ° to 20 °, which is very small compared to the usual amplitude of 300 ° of a balance spring, and which does not not allow their direct combination with conventional exhaust mechanisms, and in particular with usual retainers such as a Swiss anchor or the like, which require a large angular travel to ensure their proper functioning.

During the Chronometry Congress in Montreux, Switzerland, on September 28 and 29, 2016, the de team. H. Kahrobaiyan discussed the increase in this angular travel in the article "Gravity insensitive flexure pivots for watch oscillators", and it appears that the solution -complex- envisaged is not isochronous.

Document EP 3 035 127 A1 in the name of the same applicant SWATCH GROUP RESEARCH & DEVELOPMENT Ltd describes a clock oscillator comprising a time base with at least one resonator constituted by a tuning fork which comprises at least two oscillating moving parts, said movable parts being fixed to a connecting element, which comprises said oscillator, by flexible elements whose geometry determines a virtual pivot axis of position determined relative to said connecting element, around which virtual pivot axis oscillates said respective movable part , whose center of mass coincides in the rest position with said respective virtual pivot axis. For at least one said movable part, said flexible elements consist of crossed elastic blades and extending at a distance from each other in two parallel planes, and the projections of the directions on one of said parallel planes intersect at the level of said virtual pivot axis, of said movable part considered.

Document US 3,628,781A in the name of GRIB describes a tuning fork, in the form of a double cantilever structure, to allow an accentuated rotational movement of a pair of mobile elements, with respect to a fixed reference plane comprising a first elastically deformable body having at least two elastically similar elongated flexible parts, the ends of each of said flexible parts being respectively integral with enlarged rigid parts of said element, the first of said rigid parts being fixed to define a reference plane and the second being resiliently supported to have an accentuated rotational movement with respect 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 body elastically deformable in relation to esp acée to provide a tuning fork structure in which each of the tuning fork teeth includes the free end of one of said elastically deformable bodies.

Document EP 3 130 966 A1 in the name of ETA Manufacture Horlogère Suisse describes a mechanical clockwork movement which comprises at least one barrel, a set of gear wheels driven at one end by the barrel, and a mechanism for exhaust of a local oscillator with a resonator in the form of a balance-spring and a clock movement feedback system. The escapement mechanism is driven at another end of the gear wheel assembly. The feedback system comprises at least one precise reference oscillator, combined with a path comparator to compare the path of the two oscillators, and a mechanism for adjusting the resonator of

CH 714 030 A2 the local oscillator to slow down or speed up the resonator based on a result of the comparison in the walking comparator.

Document CH 709 536 A2 in the name of ETA Manufacture Horlogère Suisse describes a clockwork regulating mechanism comprising, mounted movably, at least in pivoting relative to a plate, an escapement wheel arranged to receive a motor 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 comprises guide means arranged to cooperate with complementary guide means which comprises said escape wheel, synchronizing said first oscillator and said second oscillator with said train.

Patent application EP 17 183 666 by the same applicant, incorporated here 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 approximately 45% of their length, and by introducing an offset of the center of mass of the resonator with respect to the axis of rotation, it is possible to simultaneously obtain good isochronism and insensitivity to positions over a large angular travel (up to 40 ° or more). In order to maximize the angular travel while retaining good off-plane rigidity, we tend to refine the blades while increasing their height. The use of a large value of the aspect ratio, that is to say the ratio between the height of the blade over its thickness is theoretically advantageous, but in practice it is observed that for large angular amplitudes it is produces an inhibition of anticlastic curvature, which alters the isochronism properties of the resonator.

Claims (20)

Summary of the invention The invention proposes to develop a mechanical oscillator with flexible guides, the angular travel of which is compatible with existing exhaust mechanisms, and whose flexible guides behave regularly regardless of either their deformation. This flexible rotationally guided resonator must have the following properties: - a high quality factor; - a large angular stroke; - good isochronism; - great insensitivity to positions in space. Considering the particular case of a flexible guide with crossed blades in projection in a plane parallel to the oscillation plane, where these blades join a fixed mass and a mobile mass, the possible angular travel 9 of the pivot depends on the ratio X = D / L enters, on the one hand the distance D from the point of embedding of a blade in 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 recesses. The work cited above from the Μ team. H. Kahrobaiyan show that this possible angular travel 8 is, for a given pair of blades and angle at the top given at the crossing point, here of 90 °, maximum for X = D / L = 0.5, and decreases rapidly when we deviate from this value, according to a substantially symmetrical curve. However, such a pivot with crossed blades with X = D / L = 0.5 and a = 90 ° is not isochronous. The invention therefore explores the areas of favorable combinations between the angle values at the apex at the intersection of the blades, and the values of the ratio X = D / L, to obtain isochronous pivots, as well as the values optimal aspect ratio of each blade. To this end, the invention relates to a mechanical oscillator according to claim 1. And in particular the invention shows that one can obtain an isochronous oscillator with pivots which verify both the two inequalities: 0.15 <(X = D / L) <0.85, and at <60 °. Naturally, the configurations with a = 0 ° are discarded, the blades then no longer being intersecting in projection, but parallel. The invention also relates to a timepiece movement comprising at least one such mechanical oscillator. The invention also relates to a watch comprising such a clockwork movement. Brief description of the drawings [0021] Other characteristics and advantages of the invention will appear on reading the detailed description which follows, with reference to the accompanying drawings, where: fig. 1 shows, schematically, and in perspective, a first variant of a mechanical oscillator, which comprises a first rigid support element, of elongated shape, for its attachment to a movement plate or the like, from which a second inertia element is suspended! solid by two first disjointed hoses, crossed in projection on the plane of oscillation of this second inertial element, which cooperates with a conventional escapement mechanism with Swiss anchor and standard escapement wheel; CH 714 030 A2 fig. 2 shows schematically and in plan the oscillator of fig. 1; fig. 3 shows schematically, and in section passing through the axis of intersection of the blades, the oscillator of FIG. 1; fig. 4 shows, schematically, a detail of FIG. 2, showing the offset between the crossing of the blades and the projection of the center of mass of the resonator, this detail with offset being applicable in the same way to the different variants described below; fig. 5 is a graph, with abscissa X = D / L between, on the one hand the distance D from the point of embedding of a blade in the fixed mass and the crossing point, and on the other hand the total length L of this same blade between its two opposite recesses, and on the ordinate the angle at the top of the crossing of the flexible blades, and which defines two curves, lower and upper, in broken lines, which limit the suitable range between these parameters to ensure the isochronism, the curve in solid line corresponding to an advantageous value; fig. 6 represents, similarly to FIG. 1, a second variant of a mechanical oscillator, where the first rigid support element, of elongated shape, is also movable relative to a fixed structure, and is carried by a third rigid element, by means of a second set of flexible blades, arranged similarly to the first flexible blades, the second inertial element being further arranged to cooperate with a conventional exhaust mechanism not shown; fig. 7 shows schematically and in plan the oscillator of fig. 6; fig. 8 shows schematically, and in section passing through the axis of intersection of the blades, the oscillator of FIG. 1; fig. 9 is a block diagram representing a watch which includes a movement with such a resonator; fig. 10 shows, schematically and in perspective, a guide with flexible blades crossed in projection, between a fixed structure and an inertial element; fig. 11 represents, similarly to FIG. 10, a theoretical flexible guide, each blade of which has an aspect ratio greater than that of the blades of FIG. 10; fig. 12 represents, similarly to FIG. 10, a flexible guide according to the invention, equivalent in terms of elastic return to the theoretical guide in FIG. 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 cross in projection two elementary blades of a second type which are also superimposed between them and extend in a second direction; fig. 13 represents, similarly to FIG. 12, another flexible guide according to the invention, the four blades of which are staggered; fig. 14 represents, similarly to FIG. 12, yet another flexible guide according to the invention, the four blades of which comprise two elementary blades of a first type in a first direction, which frame two elementary blades of a second type which are superposed between them and extend in a second direction; fig. 15 represents, similarly to FIG. 12, another flexible guide according to the invention, comprising six blades superimposed by three; fig. 16 represents, similarly to FIG. 13, another flexible guide according to the invention, the six blades of which are staggered; fig. 17 represents, similarly to FIG. 14, another flexible guide according to the invention, the eight blades of which 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 between they and extend in a second direction; fig. 18 represents, similarly to FIG. 12, yet another flexible guide according to the invention, 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 between them and extend in a second direction. CH 714 030 A2 Detailed description of the preferred embodiments The invention thus relates to a mechanical oscillator 100 for timepieces, comprising at least a first rigid support element 4 and a second solid inertial element 5. This oscillator 100 comprises, between the first support element rigid 4 and the second massive inertial element 5, at least two first flexible blades 31, 32, which support the second massive inertial element 5, and which are arranged to return it to a rest position. This second massive inertial element 5 is arranged to oscillate angularly according to a plane of oscillation around this rest position. The first two flexible blades 31 and 32 do not touch, and in the rest position, their projections on the plane of oscillation intersect at a crossing point P, in the immediate vicinity of which or through which the axis of rotation of the second massive inertial element 5 perpendicular to the plane of oscillation. All the geometric elements described below are understood, unless otherwise stated, to be considered in the rest position of the oscillator when stopped. Figs. 1 to 4 illustrate a first variant with a first rigid support element 4 and a second massive inertial element connected by two first flexible blades 31,32. The recesses of the first flexible blades 31, 32, with the first rigid support element 4 and the second massive inertial element 5 define two directions of blades DL1, DL2, which are parallel to the plane of oscillation and which form therebetween, in projection on the plane of oscillation, an angle at the top a. The position of the crossing point P is defined by the ratio X = D / L where D is the distance between the projection, on the plane of oscillation, of one of the points of embedding 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, on the plane of oscillation, of the blade 31, 32, concerned. And the value of the D / L ratio is between 0 and 1, and the angle at the top a is less than or equal to 70 °. Advantageously, both the apex angle a is less than or equal to 60 °, and, for each first flexible strip 31.32, the embedding ratio D1 / L1, D2 / L2, is understood between 0.15 and 0.85, limits included. In particular, as shown in Figs. 2 to 4, the center of mass of the oscillator 100 in its rest position is distant from the crossing point P by a difference s which is between 10% and 20% of the total length L of the projection, on the oscillation plane, of the blade 31.32. More particularly still, the difference e is between 12% and 18% of the total length L of the projection, on the plane of oscillation, of the blade 31, 32. More particularly, and as illustrated in the figures, the first blades 31, 32, and their recesses together define a pivot 1 which, in projection on the plane of oscillation, is symmetrical with respect to an axis of symmetry AA passing through the crossing point P. More particularly, when the pivot 1 is symmetrical relative to the axis of symmetry AA, in the rest position, in projection on the plane of oscillation, the center of mass of the second massive inertial element 5 is located on the axis of symmetry AA of pivot 1. In projection, this center of mass may or may not coincide with the crossing point P. More particularly still, the center of mass of the second massive inertial element 5 is located at a non-zero distance from the crossing point P corresponding to the axis of rotation of the second massive inertial element 5, as shown in FIGS. 2 to 4. In particular, in projection on the oscillation plane, the center of mass of the second massive inertial element 5 is located on the axis of symmetry AA of the pivot 1, and is located at 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 31.32. More particularly, the first blades 31 and 32 are straight blades. More particularly still, the apex angle a is less than or equal to 50 °, or is less than or equal to 40 °, or even less than or equal to 35 °, or even less than or equal to 30 °. More particularly, the embedding ratio D1 / L1, D2 / L2, is between 0.15 and 0.49, terminals included, or between 0.51 and 0.85, terminals included, as shown in fig. 5. In a variant, and more particularly according to the execution according to FIG. 5, the angle at the top a is less than or equal to 50 °, and the embedding ratio D1 / L1, D2 / L2, is between 0.25 and 0.75, limits included. In a variant, and more particularly according to the execution according to FIG. 5, the apex angle a is less than or equal to 40 °, and the embedding ratio D1 / L1, D2 / L2, is between 0.30 and 0.70, limits included. In a variant, and more particularly according to the execution according to FIG. 5, the angle at the top a is less than or equal to 35 °, and the embedding ratio D1 / L1, D2 / L2, is between 0.40 and 0.60, limits included. Advantageously, and as visible in FIG. 5, the angle at the top a and the ratio X = D / L satisfy the relation: h1 (D / L) <a <h2 (D / L), with, for 0.2 <X <0.5: H1 (X) = 116-473 * (X + 0.05) + 3962 * (X + 0.05) ^3-6000 * (X + 0.05) ^4, h2 (X) = 128-473 * (X-0.05) + 3962 * (X-0.05) ³ -6000 * (X-0.05) ⁴ , for 0.5 <X <0.8: CH 714 030 A2 h1 (X) = 116-473 * (1.05-X) + 3962 * (1.05-X) ³ -6000 * (1.05-X) ⁴ , h2 (X) = 128-473 * (0.95-X ) + 3962 * (0.95-X) ³ -6000 * (0.95-X) ⁴ . More particularly, and in particular 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. More particularly, between their recesses, these first flexible blades 31 and 32 are identical. Figs. 6 to 8 illustrate a second variant of mechanical oscillator 100, where the first rigid support element 4 is also movable, directly or indirectly relative to a fixed structure that this oscillator 100 comprises, and is carried by a third rigid element 6, by by means of two second flexible blades 33, 34, arranged similarly to the first flexible blades 31, 32. 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 intersect at the same crossing point P. In another particular embodiment not shown, in the rest position, in projection on the oscillation plane, the projections of the first flexible blades 31, 32, and of the second flexible blades 33, 34, on the plane of oscillation intersect at two distinct points, both located on the axis of symmetry AA of pivot 1, when pivot 1 is symmetrical with respect to the axis of symmetry AA. More particularly, the recesses of the second flexible blades 33, 34, with the first rigid support element 4 and the third rigid element 6, define two directions of blades parallel to the plane of oscillation and forming between them, in projection on the oscillation plane, an angle at the top of the same bisector as the angle at the top has that the first flexible blades 31,32. More particularly still, these two directions of the second flexible blades 33, 34 have the same angle at the top a as the first flexible blades 31, 32. More particularly, the second flexible blades 33, 34 are identical to the first flexible blades 31, 32, as in the nonlimiting example of the figures. More particularly, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, in the rest position, in projection on the plane of oscillation, the center of mass of the second massive inertial element 5 is located on the axis of symmetry AA of pivot 1. In a similar and particular way, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, in the rest position, the center of mass of the first rigid support element 4 is located, in projection on the plane of oscillation, on the axis of symmetry AA of pivot 1. In a particular variant, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, in the rest position, in projection on the plane of oscillation, both the center of mass of the second massive inertial element 5 and the center of mass of the first 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 second massive inertial element 5 and of the center of mass of the first support element rigid 4, on the axis of symmetry AA of pivot 1, are combined. A particular configuration illustrated by the figures for such superimposed pivots is that in which the projections of the first flexible blades 31, 32, and of the second flexible blades 33, 34, on the plane of oscillation intersect at the same crossing point. P, which also corresponds to the projection of the center of mass of the second massive inertial element 5, or at least which is as close as possible to it. More particularly, this same point also corresponds to the projection of the center of mass of the first rigid support element 4. More particularly still, this same point also corresponds to the projection of the center of mass of the entire oscillator 100. In a particular variant of this configuration of superimposed pivots, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, in the rest position, in projection on the plane of oscillation, the center of mass of the second 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 second massive inertial element 5, 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 33, 34, with a deviation similar to the deviation z of FIGS. 2 to 4. In a similar and particular way, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, the center of mass of the second massive inertial element 5 is located, in projection on 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 first 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. Similarly and in a particular way, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, the center of mass of the first rigid support element 4 is located, in projection on the plane of oscillation, on the axis of symmetry AA of pivot 1 and at a non-zero distance from the crossing point P corresponding to the axis of rotation of the second 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. CH 714 030 A2 Similarly and particularly, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, the center of mass of the first rigid support element 4 is located, in projection on 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 first 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. Similarly and in particular, the center of mass of the first 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. More particularly, and as visible in the variant of the figures, when the pivot 1 is symmetrical with respect to the axis of symmetry AA, in projection on the plane of oscillation, the center of mass of the oscillator 100 in its rest position is located on the axis of symmetry AA. More particularly, the second massive inertial element 5 is elongated in 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 figs. 1 to 4 where the inertial element 5 comprises a base on which is fixed a traditional pendulum with long arms provided with sections of serge or weights in an arc of a circle. The objective is to minimize the influence of external angular accelerations around the axis of symmetry of the pivot, because the blades have a low rigidity in rotation around this axis because of the small angle a. The invention lends itself well to a monolithic execution of the blades and the massive components which they join, made of micro-machinable material or at least partially amorphous, with an implementation by “MEMS” or “LIGA” process or similar. In particular, in the case of an execution in silicon, the oscillator 100 is advantageously thermally compensated by adding silicon dioxide on flexible silicon wafers. In a variant, the blades can be assembled, for example embedded in grooves, or the like. When there are two pivots in series, as in the case of FIG. 6 to 9, the center of mass can be placed on the axis of rotation, in the case where the arrangement is chosen so that the parasitic displacements compensate each other, which constitutes an advantageous but non-limiting variant. It should be noted, however, that it is not necessary to choose such an arrangement, and such an oscillator operates with two pivots in series without positioning the center of mass on the axis of rotation. Of course, even if the illustrated embodiments correspond to particular geometrical configurations of alignment, or of symmetry, it is understood that it is also possible to stack two different pivots, or with different crossing points, or with centers of non-aligned masses, or to implement a greater number of sets of blades in series, with intermediate masses, to further increase the amplitude of the balance. The illustrated variants include all the pivot axes, blade crossings, and centers of mass, coplanar, which is a special advantageous but not limiting case. It is understood that the invention makes it possible to obtain an angular travel which is large: in any case greater than 30 °, it can even reach 50 ° or even 60 °, which makes it compatible in combination with all the exhausts usual mechanical, Swiss anchor, detent, coaxial, or other. It is also a question of determining a practical solution which is equivalent to the theoretical use of a large value of the aspect ratio of the blades. To this end, the invention subdivides the blades lengthwise, by replacing a single blade with a plurality of elementary blades whose overall behavior is equivalent, and where each of the elementary blades has an aspect ratio limited to a threshold value. We thus reduce, compared to a single reference blade, the aspect ratio of each elementary blade, to find the optimum of isochronism and insensitivity to positions. Each blade 31.32, has an aspect ratio RA = O / W, where H is the height of the blade 31.32, perpendicular both to the plane of oscillation and to 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. According to the invention, the aspect ratio RA = O / W is less than 10 for each blade 31, 32. More particularly, this aspect ratio is less than 8. And the total number of flexible blades 31, 32, is strictly greater than two. More particularly, the oscillator 100 comprises a first number N1 of first blades called primary blades 31 extending in a first direction of blade DL1, and a second number N2 of first blades called secondary blades 32 extending in a second blade direction DL2, the first number N1 and the second number N2 each being greater than or equal to two. More particularly, the first number N1 is equal to the second number N2. More particularly still, the oscillator 100 comprises at least one pair formed by a primary blade 31 extending in a first direction of blade DL1, and a secondary blade 32 extending in a second direction of blade DL2. And, in each pair, the primary blade 31 is identical to the secondary blade 32 in the orientation. CH 714 030 A2 In a particular variant, the oscillator 100 only comprises pairs each formed by a primary blade 31 extending in a first blade direction DL1, and a secondary blade 32 extending in a second direction of blade DL2, and, in each pair, the primary blade 31 is identical to the secondary blade 32 except for the orientation. In another variant, the oscillator 100 comprises at least one group of blades formed by a primary blade 31 extending in a first blade direction DL1, and a plurality of secondary blades 32 extending according to 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 accumulation of the plurality of secondary blades 32 except for the orientation. We also note that, if the behavior of a flexible blade depends on its aspect ratio RA, it also depends on the value of the curvature which is printed on it. Its deformation depends on both the value of the aspect ratio and the local value of the radius of curvature, in particular at embedding. This is the reason why, preferably, a symmetrical arrangement of the blades is adopted in planar projection. The invention also relates to a clockwork movement 1000 comprising at least one such mechanical oscillator 100. The invention also relates to a watch 2000 comprising at least one such clockwork movement 1000. A suitable manufacturing process consists in carrying out the following operations for the different types of pivots below: For a type of AABB pivot according to the diagram in FIG. 12: at. use a substrate with at least four layers, resulting for example but not limited to the assembly of two SOI wafers; b. engraving by “DRIE” engraving process on the front face to obtain AA, in particular engraving the two layers in one piece; vs. engraving by engraving process "DRIE" back face to obtain BB, with in particular engraving of the two layers in one piece; d. Partially separate the four layers by etching the buried oxide. The high precision of the “DRIE” process, that is to say deep reactive ion etching (in English Deep Reactive Ion Etching DRIE) guarantees very good positioning and alignment precision, less than or equal to 5 micrometers, thanks to an optical alignment, which guarantees a very good alignment face to face. Of course, equivalent methods can be used depending on the material chosen. It is possible to use substrates with a higher number of layers, in particular a substrate with six available layers, for example by assembling two DSOIs, to obtain a structure of the AAABBB type. A variant for obtaining the same type of AABB pivot consists in: at. use two standard two-layer SOI substrates; b. etching by “DRIE” etching process the first substrate, on the front face to obtain A, on the rear face to obtain A; vs. etching by “DRIE” etching process the second substrate, on the front face to obtain B, on the rear face to obtain B; as an alternative to operations b and c, it is possible, on the first substrate and on the second substrate, to carry out etching in addition to the two layers at once, without effecting etching on the front and rear sides; d. perform the "wafer to wafer" assembly of the two substrates or "piece by piece" of the individual components, to obtain AABB. The correct alignment of the geometries is then linked to the specification of the "wafer to wafer" bonding machine or to the "piece to piece" process, in a manner well known to the skilled person. For a type of ABAB pivot according to the diagram in FIG. 13: at. use two standard two-layer SOI substrates; b. etching by “DRE” etching process the first substrate, on the front face to obtain A, on the rear face to obtain B; CH 714 030 A2 vs. engraving by “DRIE” etching process the second substrate, on the front face to obtain A, on the rear face to obtain B; d. perform the "wafer to wafer" assembly of the two substrates or "piece by piece" of the individual components, to obtain ABAB. As before, The correct alignment of the geometries is linked to the specification of the "wafer to wafer" bonding machine or to the "piece to piece" process. Many other process variants can be implemented, depending on the number of blades and the equipment available. claims 1. Mechanical clock oscillator (100), comprising, between a first rigid support element (4) and a second solid inertial element (5), a flexible guide comprising at least two first flexible blades (31; 32) which support said second massive inertial element (5) and are arranged to return it to a rest position, said second massive inertial element (5) being arranged to oscillate angularly according to an oscillation plane around said rest position, said two first flexible blades (31; 32) not touching and their projections on said oscillation plane crossing, in the rest position, at a crossing point (P), in the vicinity of which or through which passes the axis of rotation of said second element massive inertial (5) perpendicular to said plane of oscillation, and the recesses of said first flexible blades (31; 32) with said first rigid support element (4) and said second element i massive inertia (5) defining two directions of blades (DL1; DL2) parallel to said plane of oscillation, each said blade (31; 32) having an aspect ratio RA = O / W, where H is the height of said blade (31; 32) perpendicular both to the plane of oscillation and elongation of said blade (31; 32) along said length L, and where E is the thickness of said blade (31; 32) in the plane of oscillation and perpendicular to the elongation of said blade ( 31; 32) along said length L, characterized in that said aspect ratio RA = O / W 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. 2. Mechanical oscillator (100) according to claim 1, characterized 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 said 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. 3. Mechanical oscillator (100) according to claim 2, characterized in that said first number N1 is equal to said second number N2. 4. Mechanical oscillator (100) according to claim 2 or 3, characterized in that said oscillator comprises at least one pair formed by a said primary blade (31) extending in a first blade direction (DL1), and d 'a 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 for the orientation . 5. Mechanical oscillator (100) according to claim 4, characterized in that said oscillator comprises only said pairs each formed by a said primary blade (31) extending in a first blade direction (DL1), and d 'a 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 for the orientation . 6. Mechanical oscillator (100) according to claim 2 or 4 according to 2, characterized in that said oscillator comprises at least one group of blades formed of a 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 behavior of said primary blade (31) is identical to the elastic behavior resulting from said plurality of secondary blades (32) except for the orientation. 7. Mechanical oscillator (100) according to one of claims 1 to 6, characterized in that said first blades (31; 32) are straight blades. 8. Mechanical clock oscillator (100), according to one of claims 1 to 7, characterized in that said two blade directions (DL1; DL2) parallel to said oscillation plane form between them, in the rest position, in projection on said oscillation plane, an angle at the apex a, the position of said crossing point (P) being defined by the ratio X = D / L, where D is the distance between the projection, on said oscillation plane , from one of the points of embedding 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, on said plane of oscillation, of said blade (31; 32) in its elongation, and in that said embedding ratio (D1 / L1; D2 / L2) is between 0.15 and 0.49, limits included, or between 0.51 and 0.85, terminals included. 9. Mechanical oscillator (100) according to claim 8, characterized in that said apex angle (a) is less than or equal to 50 °, and characterized in that said embedding ratio (D1 / L1; D2 / L2) is between 0.25 and 0.75, limits included. CH 714 030 A2 10. Mechanical oscillator (100) according to claim 9, characterized in that said apex angle (a) is less than or equal to 40 °, in that said embedding ratio (D1 / L1; D2 / L2) is included between 0.30 and 0.70, limits included. 11. Mechanical oscillator (100) according to claim 10, characterized in that said apex angle (a) is less than or equal to 35 °, in that said embedding ratio (D1 / L1; D2 / L2) is understood between 0.40 and 0.60, limits included. 12. Mechanical oscillator (100) according to one of claims 1 to 11, characterized in that said apex angle (a) is less than or equal to 30 °. 13. Mechanical oscillator (100) according to one of claims 1 to 12, characterized in that said apex angle (a) and said ratio X = D / L satisfy the relationship: h1 (D / L) <a <h2 (D / L), with, for 0.2 <X <0.5: h1 (X) = 116-473 * (X + 0.05) + 3962 * (X + 0.05) ³ -6000 * (X + 0.05) ⁴ , h2 (X) = 128-473 * (X-0.05) + 3962 * (X-0.05) ³ -6000 * (X-0.05) ⁴ , for 0.5 <X <0.8: h1 (X) = 116-473 * (1.05-X) + 3962 * (1.05-X) ³ -6000 * (1.05-X) ⁴ , h2 (X) = 128-473 * (0.95-X) + 3962 * (0.95-X) ³ -6000 * (0.95-X) ⁴ . 14. Mechanical oscillator (100) according to one of claims 1 to 13, characterized in that the center of mass of said oscillator (100) in its rest position is distant from said crossing point (P) by a distance (e ) which is between 10% and 20% of the said total length L of the projection, on the said oscillation plane, of the said blade (31; 32). 15. Mechanical oscillator (100) according to claim 14, characterized in that said deviation (t) is between 12% and 18% of said total length L of the projection, on said oscillation plane, of said blade (31 ; 32). 16. Mechanical oscillator (100) according to one of claims 1 to 15, characterized in that said first blades (31; 32) and their recesses together define a pivot (1) which, in projection on said plane of oscillation, is symmetrical about an axis of symmetry (AA) passing through said crossing point (P). 17. Mechanical oscillator (100) according to claim 16, characterized in that, in the rest position, in projection on said oscillation plane, the center of mass of said second massive inertial element (5) is located on said axis of symmetry (AA) of said pivot (1). 18. Mechanical oscillator (100) according to claim 17, characterized in that, in projection on said oscillation plane, the center of mass of said second massive inertial element (5) is at a non-zero distance from said crossing point (P ) corresponding to the axis of rotation of said second massive inertial element (5), which non-zero distance is between 0.1 times and 0.2 times said total length L of the projection, on said oscillation plane, of said blade (31; 32 ). 19. Clock movement (1000) comprising at least one mechanical oscillator (100) according to one of claims 1 to 18. 20. Watch (2000) comprising at least one clockwork movement (1000) according to claim 19. CH 714 030 A2