EP3637196B1 - Mechanical oscillator - Google Patents

Description

Technical area

The present invention relates to the field of watchmaking. It relates more particularly to a mechanical oscillator without a pivot and comprising a balance suspended from the frame by means of a plurality of elastic systems.

State of the art

The document EP 2 273 323 describes an oscillator of the aforementioned type, in which a balance is suspended from a frame element by elastic systems arranged in series. These each include a pair of blades extending in a "V" between a rigid central part and an arcuate frame, and serve to provide the return torque for the balance as well as to support the latter. In the upper level of this construction, the frame is arranged to be screwed onto a frame element such as a plate or a bridge, and the rigid central part is fixed to that of the adjacent level. The frame of this last level is in turn fixed to the frame of the next elastic system, which is fixed by its rigid central part to the subsequent elastic system. This sequence continues up to the balance wheel, which is fixed at its center to the rigid central part of the last elastic system.

In this arrangement, several of the elastic systems are linked together by their rigid central parts, and the balance is also fixed to the rigid central part of the last elastic system. Consequently, the angular rigidity of the suspension of the mass, considered along the two axes perpendicular to the axis of rotation of the mass, is not optimal, and the latter can thus tilt slightly, in particular in the event of an angular shock tending in causing the balance to pivot about an axis substantially perpendicular to the axis of rotation of the balance.

Furthermore, during oscillations, the shear generated in the central links is relatively high, which increases the risk of these interfaces breaking.

Finally, we note that each individual elastic system is extremely unbalanced around the virtual axis of rotation, which gives rise to unwanted movements and parasitic forces.

Other forms of oscillators without conventional pivots are also disclosed by the documents EP3299905 , CH710759 , EP3147725 and US2016 / 011566 .

The aim of the invention is therefore to provide a mechanical oscillator in which the aforementioned defects are at least partially overcome.

Disclosure of the invention

More precisely, the invention relates to a mechanical oscillator for a timepiece comprising a suspended balance, of any shape, arranged to oscillate about a geometric axis of rotation, that is to say an axis virtual without conventional shafts and pivots. A plurality of elastic systems arranged in series connect said balance to an attachment member arranged to fix said oscillator directly or indirectly to a structural element that said timepiece comprises, such as a fixed frame element, a tourbillon cage. or carousel or the like. To this end, the elastic systems have a stiffness considered parallel to the axial direction which is sufficient to suspend and to support the balance regardless of the orientation of the system with respect to the direction of the gravity vector, and an elasticity around said axis of rotation adapted to allow the balance to oscillate in rotation.

According to the invention, each elastic system comprises an even number of at least four outer frames (that is to say four, six, eight or even more) and at least two inner connecting elements. Each frame carries two (or even more) elastic elements (blades elastic, combinations of rigid bars and blades or collars, or the like which ensure the elasticity of the elastic element considered as a whole) each extending between said frame and one of said inner connecting elements.

Each internal connecting element is connected to the two elastic elements carried by one of said frames, as well as to an adjacent elastic element of each of the other frames of the same elastic system located on either side of said frame considered.

In addition, each of said elastic systems is fixed to each elastic system adjacent thereto at the level of one of its two frames (these frames being not adjacent to each other), for example by means of tenons. , pins, studs, screws, welding, gluing or the like, these means being arranged to make the frames in question mutually integral. In other words, each elastic system which is adjacent to only one other is fixed to this other by every other frame, and each elastic system which is located between two others is fixed on the one hand to a first of these other systems. by every other frame, and on the other hand to the other of these other systems by the other half of its frames.

By these means, each elastic system can be better balanced than those of the prior art and, since the elastic systems are connected in series by their frames, the force thus transmitted during the oscillations is removed from the center of rotation and consequently generates a significantly less shear in the connections between elastic systems.

• ledit balancier est relié à l'un cadre sur deux du système élastique y adjacent, cesdits cadres n'étant pas directement adjacents l'un par rapport à l'autre, les autres cadres interposés entre ceux fixés au balancier étant donc libres d'osciller par rapport à ce dernier ; ledit organe d'attache est relié à l'un cadre sur deux du système élastique y adjacent, cesdits cadres n'étant pas directement adjacents l'un par rapport à l'autre, les autres cadres interposés entre ceux fixés à l'organe d'attache étant donc libres d'osciller par rapport à l'organe d'attache.

Advantageously:

• said balance is connected to one in two frames of the elastic system adjacent to it, said frames not being directly adjacent to each other, the other frames interposed between those fixed to the balance therefore being free to oscillate in relation to the latter; said attachment member is connected to one in two frames of the elastic system adjacent thereto, said frames not being directly adjacent to one another, the other frames interposed between those fixed to the fastening member therefore being free to oscillate with respect to the fastening member.

In the case where the oscillator comprises at least three of said elastic systems, each frame belonging to each intermediate elastic system (that is to say each elastic system which is not immediately adjacent to the balance or to the member of fastener) is connected to a frame of one or other of the elastic systems adjacent thereto, half of the frames of said elastic system considered being connected to every other frame of another elastic system located opposite a first side of the elastic system considered (that is to say to the first elastic system adjacent to it), the other frames contained in said elastic system considered being connected to every other frame of another elastic system located opposite the second side of the system elastic system considered (that is to say to the second elastic system adjacent thereto), said frames of the elastic system considered being connected alternately to one or other of said adjacent elastic systems, by their frames (i.e. -to say that the ca dres of the elastic system considered are linked, by an alternating succession, to the corresponding frames of the first or of the second adjacent elastic system).

Advantageously, each elastic system is oriented at an angle of (360 / N) ° around said axis of rotation with respect to the adjacent elastic system, N being the number of frames that each of said elastic systems considered individually. So, for four frames per elastic system, the relative orientation angle is 90 °, for six frames 60 °, for eight frames 45 °, etc.

Advantageously, each resilient element comprises a substantially rigid middle bar, a first flexible strip extending between a first end of said bar and one of said inner connecting elements, as well as a second flexible strip extending between a second end of said bar. said bar, opposite to said first end, and one of said frames. Of course, the smallest dimension of the section of said blades is preferably oriented perpendicular to said axis of rotation in order to provide elasticity and rigidity in the desired directions, to obtain the operation described above. This elastic element configuration gives it a stiffness (that is to say a relationship between the angular displacement deforming this elastic element and the torque associated with it) which is substantially constant as a function of the angle of rotation of the balance, in any case more constant than other configurations. Alternatively, the elastic elements can be formed as single blades, no middle bar being present.

Advantageously, each of said internal connecting elements is connected exclusively to frames of the same elastic system by means of the corresponding elastic elements. In other words, no direct connection between an internal connection element of an elastic system and an internal connection element of the adjacent elastic system is present, the only connections between the elastic systems being at the level of the frames as described below. -above.

Advantageously, the oscillator further comprises a rod extending axially from said balance in a direction opposite to said elastic systems, said rod being arranged to take place with play in an opening provided in a structural element of said timepiece, no contact. between the rod and the opening not being present during normal operation of the oscillator. In the event of an impact having a radial component, the rod can thus come into contact with the walls of said opening, which limits the radial movement of the balance and reduces the probability that the elastic systems are damaged. If the opening also defines an axial stop for the rod, a shock tending to move the balance away from the elastic system can also be damped by limiting the movement of the balance in this direction.

Advantageously, the oscillator further comprises a screw screwed axially into the end of said rod, the head of said screw being arranged to come into contact with a stop secured to said structural element in the event of an impact in an axial direction, in particular in the event of an impact. shock tending to bring the balance closer to the elastic systems. In the case of an axial conc in the other direction, the rod can also abut against a corresponding axial stop. Consequently, in the event of an impact in any direction, the oscillator is protected since the movement of the balance is limited in any direction.

Alternatively, the oscillator may include a circlip or a washer integral in translation with said rod and arranged to come into contact with a stop integral with said structural element, and this in the event of impact in an axial direction. This stopper can be rigid or flexible.

Again alternatively, said rod comprises a circumferential groove arranged to cooperate with a stop which said structural element carries, and this in the event of impact in an axial direction. Again, this stopper can be rigid or flexible. Said groove may be machined in the rod, or may consist of a gap between two rings fixed to the latter.

Advantageously, said balance is able to perform oscillations having an amplitude of at least 15 °. With an amplitude of at least 30 °, the oscillator is thus compatible with conventional escapements, such as, for example, escapements with Swiss or English lever, detent, Omega-Daniels, or similar. Of course, the amplitude can be at least 60 °, at least 90 °, or even more.

Advantageously, each elastic system 5 has a rotational symmetry of (720 / N) °, N being the number of frames that each elastic system has.

Advantageously, the mechanical oscillator can consist of two individual oscillators as described above, arranged head-to-tail and comprising a common balance. The latter can be composed of a single balance, or of two sub-balances integral in rotation with one another, for example by means of a rod extending substantially along the axis of rotation, by pillars connecting the serges of the two sub-balances, or the like.

Advantageously, at least some of said elastic elements are made of silicon provided with a layer of silicon oxide on at least some (preferably all) of their exterior surfaces. This layer makes it possible to modify the thermal coefficient of the Young's modulus of the elastic elements and thus to compensate for operating errors due to the effects of temperature variations on the materials of the elastic systems and / or of the balance.

Brief description of the drawings

• Fig. 1 est une vue isométrique, côté organe d'attache, d'un oscillateur mécanique selon l'invention en état assemblé ;
• Fig. 2 est une vue isométrique latérale de l'oscillateur mécanique de la figure 1 ;
• Fig. 3 est une vue isométrique, côté balancier, de l'oscillateur mécanique de la figure 1 ;
• Fig. 4 est une vue isométrique du balancier de l'oscillateur de la figure 1 ;
• Fig. 5 est une vue isométrique de l'un des systèmes élastiques de l'oscillateur de la figure 1 ;
• Fig. 6 est une vue isométrique, côté organe d'attache, du balancier et du système élastique y adjacent de l'oscillateur de la figure 1 ;
• Fig. 7 et 8 sont des vues isométriques de tenons utilisés pour relier les cadres de l'un des systèmes élastiques à ses voisins ;
• Fig. 9 est une vue isométrique de l'organe d'attache et le système élastique y associé de l'oscillateur de la figure 1 ;
• Fig. 10 est une vue isométrique explosée de l'oscillateur de la figure 1 ;
• Fig. 11 est une vue isométrique de deux systèmes élastiques adjacents de l'oscillateur de la figure 1 ;
• Fig. 12 est une vue isométrique coupée de l'oscillateur de la figure 1 ainsi que d'une partie du mouvement horloger dans lequel l'oscillateur est intégré ;
• Fig. 13 est une vue similaire à celle de la figure 12 dont une partie a été agrandie, illustrant une variante de l'agencement de protection antichoc ;
• Fig. 14 est une vue isométrique coupée agrandie d'encore une variante d'un agencement antichoc ;
• Fig. 15 est encore une vue isométrique coupée agrandie d'encore une autre variante d'un agencement antichoc ;
• Fig. 16 est encore une vue isométrique coupée agrandie d'encore une autre variante d'un agencement antichoc ; et
• Fig. 17 est une vue isométrique coupée d'une autre variante d'un oscillateur selon l'invention.

Other details of the invention will emerge more clearly on reading the description which follows, given with reference to the appended drawings in which:

• Fig. 1 is an isometric view, on the attachment member side, of a mechanical oscillator according to the invention in assembled condition;
• Fig. 2 is a side isometric view of the mechanical oscillator of the figure 1 ;
• Fig. 3 is an isometric view, on the balance side, of the mechanical oscillator of the figure 1 ;
• Fig. 4 is an isometric view of the balance wheel of the oscillator of the figure 1 ;
• Fig. 5 is an isometric view of one of the elastic systems of the oscillator of the figure 1 ;
• Fig. 6 is an isometric view, on the fastening member side, of the balance and of the adjacent elastic system of the oscillator of the figure 1 ;
• Fig. 7 and 8 are isometric views of tenons used to connect the frames of one of the elastic systems to its neighbors;
• Fig. 9 is an isometric view of the attachment member and the associated elastic system of the oscillator of the figure 1 ;
• Fig. 10 is an exploded isometric view of the oscillator of the figure 1 ;
• Fig. 11 is an isometric view of two adjacent elastic systems of the oscillator of the figure 1 ;
• Fig. 12 is a cutaway isometric view of the oscillator of the figure 1 as well as part of the watch movement in which the oscillator is integrated;
• Fig. 13 is a view similar to that of the figure 12 part of which has been enlarged, illustrating a variant of the shock protection arrangement;
• Fig. 14 is an enlarged cutaway isometric view of a still variant of a shockproof arrangement;
• Fig. 15 is yet an enlarged cutaway isometric view of yet another variation of a shockproof arrangement;
• Fig. 16 is yet an enlarged cutaway isometric view of yet another variation of a shockproof arrangement; and
• Fig. 17 is a cutaway isometric view of another variant of an oscillator according to the invention.

Embodiments of the invention

In the following description, the term “rigid” means that an element is not likely to deform substantially during normal operation of the oscillator, in at least one given direction. Without an indication of such a direction, a "rigid member" is considered to be rigid in any direction. The term “elastic” on the other hand means that an elastic deformation of an element is desired during said operation, also in at least one given direction, this deformation having a desired effect on the operation of the oscillator. If an element is rigid in a first direction and elastic in a second direction, this will be clearly indicated in the text. Furthermore, in order not to overload the figures, the set of reference signs does not appear on each drawing. Finally, we note that, in the absence of any other explicit indication to the contrary, the spatial relations between elements are defined by default when the oscillator is at rest, and the axial direction is determined with respect to the axis of rotation 9 .

The figures 1 to 3 illustrate a mechanical oscillator 1 according to the invention, in assembled state. This oscillator 1 comprises a balance wheel 3, which provides the inertia which, in cooperation with the elasticity of a plurality of elastic systems 5, determines the frequency of oscillation of oscillator 1 when the latter is running, that is, that is, when it is put into oscillation. These elastic systems 5 are arranged in series so as to connect the balance 3 to an attachment member 7, the latter being arranged to be fixed directly or indirectly (for example by means of an intermediate piece) to a fixed element. of a timepiece such as a bridge, a plate or the like or a tourbillon cage. In this way, the balance 3 is suspended and can pivot substantially around a non-physical axis of rotation 9, that is to say around a virtual, geometric axis and not around a shaft mounted between bearings. conventional. Oscillator 1 is thus devoid of pivots, which reduces friction and improves its quality factor compared to a conventional balance-spring oscillator.

The balance 3 of the illustrated embodiment, which is shown in isolation on the figure 4 , is formed of a substantially rigid frame defining a peripheral rim 3a as well as a central hub 3b, these two elements being interconnected by a plurality of arms 3c. Additional arms 3d extend cantilevered from the hub 3b in the direction of the rim 3a. The rim 3a as well as the additional arms 3d carry masses 3f, determining the inertia of the balance 3. By varying the inertia with respect to the axis of rotation 9 of the masses 3f carried by the additional arms 3d and / or those carried by the rim 3a, the resonant frequency of the oscillator 1 can be adjusted in a known manner. Alternatively, by varying the rigidity of the elastic elements 5b (for example by removing material by via a laser), it is also possible to vary the resonant frequency of the oscillator.

The hub 3b carries a 3g chainring (see figure 3 ) fixed in the central opening of the hub 3b by means of an intermediate piece 3j (see figure 12 ) and carries a rod 3k extending axially in the direction opposite to the elastic systems 5. The operation of this rod 3k will be described below in the context of the figure 12 .

The 3g plate has a 3h dowel as well as a 3i anti-overturn system in accordance with those in the document EP 3,037,894 . However, the balance 3 as well as the plate 3g, can take any known shapes, adapted to cooperate with an escapement of any kind, such as for example an English or Swiss lever escapement, a detent escapement, an escapement. Omega-Daniels or similar exhaust. As regards the serge 3a, the latter can be complete, split, or partial (for example by having only two sections in the form of a bar or in an arc of a circle as in the document EP 2 273 323 above).

As mentioned above, the balance 3 is connected to the attachment member 7 by means of a plurality of elastic systems 5, arranged in series. In the illustrated embodiment, the oscillator 1 comprises four of these systems 5, but the number may vary, for example between two and eight or even more.

The figure 5 illustrates one of these elastic systems 5 in insulation. The latter comprises four rigid frames 5a, each in an arc of a circle. These frames are each connected by means of a pair of elastic elements 5b to internal connecting members 5c, said elastic elements 5b fixed to each individual frame 5a forming an acute angle between them preferably between 45 ° and 75 °, more preferably between 50 ° and 70 °. In the illustrated embodiment, the four frames 5a are substantially identical and extend over the same angle, and the elastic system 5 has a rotational symmetry of 180 °. In this way, the angle formed between the elements elastics 5b of each frame 5a is also substantially identical. However, it is possible to vary these angles, for example by opposing pairs of frames. It should also be noted that the extension of each elastic element 5 preferably intersects the axis of rotation 9 when the oscillator is at rest.

The elastic elements 5b of the illustrated embodiment each consist of a rigid median bar 5d as well as a pair of elastic blades 5f extending on either side between the rigid bar and, on the one hand, the one of the frames 5a, on the other hand an internal connecting element 5c. The elastic elements 5b are arranged to have bending elasticity in the plane of the elastic system 5, as well as to be substantially rigid in bending perpendicular to said plane. In this way, the stiffness of the elastic element 5b perpendicular to said plane is at least ten times, preferably at least one hundred times, that in said plane, the smallest dimension of each blade 5f being in this plane and therefore perpendicular to the plane. 'axis of rotation 9. This form of elastic element 5b has an angular stiffness which is substantially constant as a function of the angle of rotation of the balance, that is to say that its elasticity coefficient remains substantially invariant during oscillations.

Alternatively, the elastic elements 5b can each take the form of a single blade, as is the case in the document EP 2 273 323 , or can take the form of any type of equivalent bending element such as, for example, arrangements of necks located on either side of the rigid bar 5d. It is also not necessary for the elastic elements 5b to be straight: in fact, they can take a large number of ad hoc shapes according to the needs of those skilled in the art, in particular curved.

The internal connecting members 5c are separated from each other by a slot 5g and are each fixed to four adjacent elastic elements 5b, of which the two in the middle are associated with one of the frames 5a, and the other two belong to each to an adjacent 5a frame corresponding, these last frames 5a being located on either side of the first frame 5a mentioned.

In order to better illustrate this aspect of the elastic system 5, the four frames 5a and their corresponding blades have been indicated by the letters "A", "B", "C" and "D" on the figure 5 .

Consequently, a first of the internal connecting members 5c is integral with a single elastic element 5b belonging to the frame A, the two elastic elements 5b of the frame B, as well as only one of the elastic elements 5b of the frame C, according to this sequence. Likewise, the other internal connecting member 5c is secured to the other elastic element 5b of the frame C, to the two elastic elements 5b of the frame D, as well as to the other elastic element 5b of the frame A.

Even if each elastic system 5 as illustrated comprises four frames 5a each associated with two elastic elements 5b, one can also provide six or even eight, which will increase the number of internal connecting elements 5c to three or four respectively, each remaining inner connecting element 5c associated with four adjacent elastic elements 5b as described above. For this purpose, the rotational symmetry of each elastic system 5 is (720 / N) °, where N is the number of frames 5a per elastic system 5.

As mentioned above, the elastic systems 5 are connected in series between the balance 3 and the attachment member 7, as explained in detail below.

On the balance 3 side, the latter is fixed to two opposing frames 5a of a first elastic system 5 by means of tenons 11 (see in particular figure 6 ) which ensure not only the fixing of these components relative to each other, but also a predetermined separation between the balance 3 and the elastic system 5.

These tenons 11 can take various forms, of which two different and non-limiting examples are illustrated on the figures 7 and 8 , but it is also possible to fix the frames 5a to each other by means of any spacers, regardless of the additional parts, or the parts integrally with the frames 5a.

The figure 7 illustrates a first tenon 11 which can in particular be manufactured from a plate of micromachinable material such as silicon. To this end, the tenon 11 comprises two heads 11a extending in two opposite directions, and separated by a spacer 11b of rectangular section, and can be formed by etching (laser, chemical (for example DRIE), by dry process. .), electroforming (for example LIGA or other), by an additive process (3D printing), or any other similar process. The heads 11a are arranged to be fixed in corresponding openings having complementary shapes provided in the elements to be connected by driving, gluing, welding, clipping or the like. The spacer 11b serves to define a predetermined separation between the two elements thus fixed to one another, so that the frames 5a, the elastic elements 5b and the internal connecting elements 5c do not come into contact.

The figure 8 illustrates a conventional tenon 11, of circular section, which can be machined in a conventional manner and which does not need to be described in detail. Of course, its heads 11a as well as its spacer 11b fulfill the same functions as those of the tenon 11 of the figure 7 . Tenons 11 of this shape can also be fixed in the complementary openings by means of driving, gluing, welding, clipping or the like.

Alternatively, the tenons 11 can be integral with some of the frames 5a.

Now passing to the side opposite to the balance 3, the figure 9 illustrates the attachment member 7, which is intended to be attached to a fixed structural element of a timepiece, such as for example a bridge or a plate, or else to a movable structural element such as a watchcage. whirlpool or carousel or the like. In the illustrated embodiment, this attachment member comprises a pair of tongues 7a provided with a plurality of openings intended to receive pins of positioning, fixing screws, screw feet or the like, as well as a rigid ring 7b. Of course, other forms of attachment members are possible.

Although it is possible to fix two frames 5a of the last elastic system 5 to this ring in a similar way to the fixing of the balance to the elastic system 5 adjacent thereto, it is advantageous to form said last elastic system 5 integrally with said member. attachment 7. For this purpose, two of the frames 5a are formed integrally with the ring 7b, said frames 5a being of course opposed to one another. The other two frames 5a which are located between the fixed frames 5a are free and can thus move in the plane of this elastic system 5. In doing so, the thickness of the oscillator 1 can be reduced to a minimum, and each frame 5a which can move is located between the two fixed frames 5a.

It is also noted that it is also possible that two of the frames 5a of the last elastic system 5 can themselves act as fastening members, by being fixed directly or indirectly to a structural element of the movement, or by being integrated into this. structural element.

The figure 10 illustrates oscillator 1 in exploded view in order to illustrate more clearly the series arrangement of the various elastic systems 5.

In this figure, the level of the attachment member has been indicated as "level 1", that immediately adjacent to the balance wheel as "level 4", and the sequence of intermediate levels has been numbered as indicated in the figure. In addition, the suffixes A, B, C, D have been used to identify specific frames, following the corresponding indications in the figure 5 .

We start with the elastic system 5 of level 1 which, as a reminder, is integral with the attachment member at the level of the frames 5aB and 5aD. The other two frames 5aA and 5aC, which are free to move in their plane relative to the attachment member 7a, are attached to the two adjacent frames 5aB and 5aD of the next elastic system 5, via the aforementioned tenons 11. This last elastic system 5 is oriented at 90 ° with respect to that integrated into the fastening member and this when the oscillator 1 is at rest, so that the slots 5g between the internal connecting members 5c of each level orientates at 90 ° to each other.

The other two frames 5aA and 5aC of level 2 are in turn fixed by means of tenons 11 to the two adjacent frames 5aB and 5aD of the next elastic system 5 of level 3, the other two frames 5aA and 5aC of this level being fixed in turn to frames 5aB and 5aD respectively of level 4. Finally, the other frames 5aA and 5aC of level 4 are attached to the balance 3. Note that the elastic systems 5 of levels 2 and 3 are considered to be elastic systems 5 intermediaries, since each of these elastic systems 5 is adjacent to two others located on either side in the axial direction.

The figure 11 illustrates more clearly the relative orientation of two adjacent levels of elastic systems 5, in particular levels 4 and 3. The orientation of this view is the reverse of that of the figure 10 , and for this reason level 4 is above level 3 in this figure. It is clearly seen how the slots between the internal connecting members 5c of each adjacent level are oriented at 90 ° with respect to each other, since the two elastic systems 5 are oriented at 90 ° with respect to each other. 'other.

It should also be noted that there is no connection between the different levels at the center of the elastic systems 5, the internal connection members 5c of a given level being free with respect to those of the adjacent level. Indeed, in the proposed construction, the only connections between the levels are at the level of the frames 5a.

In the case where each elastic system comprises six frames 5a (and thus three internal connecting members 5c), the angular relationship between each elastic system 5 and the adjacent elastic systems 5 is 60 °. Likewise, in the case of eight frames per level, the angular relationship is 45 °, the same considerations also apply. More generally, for N frames, the angular relationship between adjacent elastic systems is at the rate of (360 / N) °, thanks to the rotational symmetry of (720 / N) ° of each elastic system 5.

In the illustrated embodiment, the number of elastic systems 5 is four, but the number can vary between two and eight or even more. The arrangement of four elastic systems 5 allows an amplitude of about 100 ° to 120 ° for the oscillations of the balance 3, a lower number of elastic systems 5 generating oscillations of smaller amplitude, a higher number causing oscillations of greater amplitude.

The figure 12 illustrates, in isometric view, the oscillator 1 described above, mounted on a bridge 11 integral with a plate 13 of a clockwork movement. This plate 13 also carries a finishing gear 15 and an escapement 17 in a known manner. In order to protect the oscillator 1 from shocks at least in certain directions, the free end of the cylindrical rod 3k takes place in an opening 19a provided in a ring 19 fixed in the plate 13 by driving, gluing, welding or the like. Alternatively, this opening can be formed directly in the plate 13. The opening 19a can be blind or through, and in the illustrated embodiment it is through but has a shoulder 19c against which the end of the rod 3k can abut in case of axial shock tending to move the balance 3 away from the elastic systems 5. In other construction variants not shown, the ring 19 (or the aforementioned opening formed directly in a structural element) can be provided in a bridge, an element a tourbillon or carousel cage, or any other structural element, whether fixed or mobile. This also applies for the other variants described below.

When the oscillator is at rest or operating normally, a clearance exists between the rod 3k and the interior walls of the opening 19a, these two elements therefore not coming into contact. However, in the event of a radial, axial or rotational impact about an axis other than the axis of rotation 9 of the oscillator 1, the rod 3k abuts against at least one of the interior walls of the opening 19a, in particular against its cylindrical wall or its shoulder 19c. In doing so, the movement of the balance 3 is limited, the mechanical stresses generated in the oscillator are limited and the risk of rupture of the elastic elements 5b is also minimized. However, this arrangement does not confer any protection against an axial impact tending to bring the balance 3 closer to the elastic systems 5, that is to say upwards in the orientation of this figure.

The figure 13 illustrates a variation of a shock-absorbing arrangement which differs from that of the figure 12 in that a screw 3p is screwed axially into the free end of the rod 3k, the screw not coming into contact with the walls of the opening 19a during normal operation of the oscillator 1. The opening 19a in the ring 19 defines a shoulder 19c against which the head of the screw 3p abuts in the event of an axial impact tending to bring the balance 3 of the elastic systems 5. Again, during normal operation of the oscillator, neither the rod 3k , nor the screw 3p comes into contact with any surface of the opening 19a or of the shoulder. The movement of the oscillator is thus limited in the event of an impact along any axis of translation or of rotation, with the exception of the axis of rotation 9 of oscillator 1.

The figure 14 further illustrates a variant of an anti-shock arrangement, in which the rod 3k is provided with a circlip 3m which is fixed at a suitable location, for example by clipping. Alternatively, instead of a circlip, one can use a chased, glued, welded or similar washer on the rod 3k. The axial movement of the balance 3 is limited on the one hand by the outer surface of the ring 19 which is opposite the balance 3, and on the other hand by a stop element 21 which is integral with a frame element and whose end 21a is superimposed on the circlip 3m. This stop element can take any shape, but can be for example a rocker mounted on the frame element. This rocker can for example pivot around a pin in an angular range determined by an eccentric or by other positioning means (such as for example two opposing screws), a locking device such as one or more screws or the like being able to be arranged to block the rocker in pivoting. The opening 19a in the ring 19 is cylindrical in the illustrated variant, but nothing prevents the use of a ring 19 like that of the figure 12 the opening 19a of which is partially closed by a shoulder 19c.

Consequently, during a radial or angular impact, the rod 3k abuts against the inner wall of the opening 19a, and during an axial impact, the circlip 3m abuts against one or the other of the surface of the ring 19 or the end 21a of the stop element 21.

The figure 15 illustrates yet another variant of an anti-shock arrangement, where the rod 3k has a circumferential groove 3n in which the end of a stop element 21 fixed to a frame element 13 takes place.

Again, when the oscillator 1 is at rest or operating normally, the rod 3k does not come into contact with the opening 19a, nor with the end 21a of the stop element 21, thanks to the play which is present. between these elements.

In the event of an axial impact, a surface of the groove 3n comes into contact with said end 21a, which limits the movement of the balance.

Even if a simple annular ring 19 like that of the figure 14 can be used in this variant, in the illustrated embodiment, the end 21a of the stop element 21 passes through a lateral opening 19b made in the ring 19. If the stop element stopper 21 has a certain elasticity in bending, the stopper element 21 can serve as a shock absorber. In the event of a strong axial impact, which is sufficient to cause the stop element to bend, the latter comes into contact with one or the other of the walls of said opening 19b which are located opposite the stop element 21 in order to limit the movement of the balance 3.

The figure 16 further illustrates a variant of a shock-absorbing arrangement, which differs from that of the figure 15 in that, instead of a groove 3n machined in the body of the rod 3k, two rings 3o, 3p are driven out, glued or welded to the rod 3k. These two rings 3o, 3p are separated from one another by an annular gap, which constitutes said groove 3n in which the end 21a of the stop element 21 takes place. In the illustrated variant, the diameter of the end of the rod 3k is reduced, but it is also possible that it has the same diameter at each ring 3o, 3p.

In the figures 12-16 , the oscillator 1 according to the invention has been illustrated attached to a fixed frame element of a clockwork movement. However, it can alternatively be fixed to a movable structural element, such as a tourbillon or carousel cage, or to a bridge fixed in turn to such a cage.

The fixing member 7, the elastic systems 5 as well as the frame 3a of the balance 3 are particularly suitable for manufacture by micromachining, on the basis of a non-metallic material.

As such, there may be mentioned manufacturing processes by masking and etching (wet or dry) of material plates (such as the DRIE process), laser cutting of such plates and the like. Microstructuring processes are also possible, by modifying the structure of material plates, for example by laser irradiation (in particular by “femtolaser”) and then removing the irradiated material by chemical etching. In principle, we could even create a one-piece oscillator by applying the latter process to a block of photostructurable material such as suitable glass.

Additive manufacturing processes based on 3D printing (stereolithography, selective laser sintering, selective laser melting, etc.) or on the formation of molds and their filling with material such as LIGA (Lithography, Galvanoformung, Abformung) , sintering and the like are also possible.

• Des matériaux à base de silicium, c'est-à-dire le silicium lui-même, son nitrure, son carbure ou son oxyde, sous forme amorphe, polycristallin (nanocristallin, microcristallin), monocristallin selon n'importe quel orientation cristallographique ;
• Le diamant synthétique ;
• Des céramiques telles que de l'alumine (rubis, corindon, saphir), sous forme mono- ou polycristallin ;
• Des verres, notamment des verres photostructurables comme mentionné ci-dessus ;
• Des verres céramiques ;
• Des métaux conventionnels présentant des propriétés élastiques convenables ;
• Des verres métalliques (c'est-à-dire des métaux amorphes).

As regards suitable materials, the following may be mentioned without limitation:

• Materials based on silicon, that is to say the silicon itself, its nitride, its carbide or its oxide, in amorphous, polycrystalline (nanocrystalline, microcrystalline), monocrystalline form according to any crystallographic orientation;
• Synthetic diamond;
• Ceramics such as alumina (ruby, corundum, sapphire), in mono- or polycrystalline form;
• Glasses, in particular photostructurable glasses as mentioned above;
• Ceramic glasses;
• Conventional metals exhibiting suitable elastic properties;
• Metallic glasses (that is, amorphous metals).

These materials can also be coated, for example with silicon oxide, adamantine carbon (DLC), alumina or the like, in order to modify their mechanical, thermal or optical properties, in a known manner. If the elastic systems 5 are based on silicon, an outer layer of silicon oxide can be advantageously formed on a silicon core in order to make the operation of the oscillator 1 substantially independent of the temperature by modifying the thermal coefficient of the modulus of Young of elastic elements 5b. Indeed, by varying the thickness of this layer, said thermal coefficient of the Young's modulus of the elastic elements can be made substantially zero, or can be made the inverse of that of silicon in order to compensate for the variations in rate generated by the thermal expansion of the balance. In addition, it is also possible to apply the teaching of the document EP 2 215 531 to the elastic elements 5b of the present oscillator 1. In doing so, the manufacturer can manufacture an oscillator 1 which meets the COSC criteria, the latter requiring a running precision of ± 0.6s / (j ° C).

Finally, the figure 17 illustrates yet another variant of a mechanical oscillator 1 according to the invention, which comprises two oscillators 1 as described above arranged head-to-tail and comprising a common balance 3. These two sub-oscillators are thus coupled at the level of the balance 3, and the assembly can alternatively be considered as a system of oscillators.

In other words, this variant comprises two oscillators 1 as illustrated in the figures 1 to 11 mounted in reverse orientations, their individual balances 3 being adjacent and made integral in rotation with one another in order to form a common balance which is linked at the same time to each attachment member 7 by means of a corresponding elastic system 5. In this case, the individual balances associated with each elastic system 5 are considered as “sub-balances”, their whole constituting the common balance 3.

In the illustrated variant, each elastic system 5 is identical, and the tongues 7a of each attachment member 7 extend in the same direction. However, the two elastic systems 5 may be different, and the tongues 7a may extend in different directions.

In order to constitute said common balance 3, the two individual balances, or even sub-balances, are made integral in rotation with one another by means of a rod 3k which extends substantially along the geometric axis of rotation 9, and is driven, glued, welded or similar to each sub-balance. However, pillars or the like extending between the struts or among other parts of the pendulums are also foreseeable. In addition, a single individual balance wheel is also possible as a common balance wheel.

This arrangement has greater stiffness in translation, in particular along the axis 9, as well as in torsion, in particular around any axis that is not the axis of rotation 9. The movement of the balance 3 in the event of an impact is thus reduced, regardless of a translational or rotational shock.

Although the invention has been described above in connection with specific embodiments, additional variants are also conceivable without departing from the scope of the invention as defined by the claims.

For example, it is not mandatory that each elastic system 5 be planar, more complex shapes also being possible. The various frames 5a must not be absolutely all identical in shape.

Claims (17)

1. Mechanical oscillator (1) for a timepiece, comprising:

   • a suspended balance (3) arranged so as to oscillate about a geometric axis of rotation (9),

   • a plurality of elastic systems (5) arranged in series and connecting said balance (9) to an attachment member (7) that is arranged to attach said oscillator (1) to a structural element (11) comprised by said timepiece;

   characterized in that each elastic system (5) comprises an even number of at least four exterior frames (5a) and at least two interior connection elements (5c), each frame (5a) bearing two elastic elements (5b) that each extend between said frame (5a) and one of said inner connection elements (5c); in that each interior connection element (5c) is connected to the two elastic elements (5b) borne by one of said frames (5a), and to an adjacent elastic element (5b) of each of the frames (5a) of the same elastic system (5) located on either side of the said one frame (5a);
   and in that each of said elastic systems (5) is fixed to each elastic system (5) adjacent thereto via one in two of its frames (5a), these frames (5a) being non-adjacent to one another.
2. Oscillator (1) according to Claim 1, wherein:

   • said balance (3) is connected to one frame (5a) in two of the elastic system (5) adjacent thereto, these said frames (5a) being non-adjacent to one another;

   • said attachment member (7) is connected to one frame (5a) in two of the elastic system (5) adjacent thereto, these said frames (5a) being non-adjacent to one another.
3. Oscillator (1) according to Claim 2, wherein said oscillator comprises at least three of said elastic systems (5), each frame (5a) belonging to each intermediate elastic system (5) being connected to a frame (5a) of one or other of the elastic systems (5) adjacent thereto, one frame (5a) in two of the elastic system in question being connected to one frame (5a) in two of another elastic system (5) located on a first side of the elastic system (5) in question, the other frames (5a) comprised by said elastic system (5) in question being connected to one frame (5a) in two of another elastic system (5) located on the second side of the elastic system (5) in question, said frames (5a) of the elastic system (5) in question being connected in alternation to one or other of said adjacent elastic systems (5).
4. Oscillator (1) according to one of the preceding claims, wherein each elastic system (5) is oriented relative to the elastic system (5) adjacent thereto by an angle of (360/N)° about said axis of rotation (9), N being the number of frames comprised by each elastic system (5).
5. Oscillator (1) according to one of the preceding claims, wherein each elastic element (5b) comprises:

   • a median bar;

   • a first flexible blade (5f) extending between a first end of said bar and one of said interior connection elements (5c); and

   • a second flexible blade (5f) extending between a second end of said bar, opposite said first end, and one of said frames (5a).
6. Oscillator (1) according to one of the preceding claims, wherein each one of said interior connection elements (5c) is connected only to frames (5a) of the same elastic system via the corresponding elastic elements (5b).
7. Oscillator (1) according to one of the preceding claims, further comprising a stem (3k) extending axially from said balance (3) in the opposite direction from said elastic systems (5), said stem (3k) being arranged to be placed with play in an opening (19a) provided in a structural element (13) of said timepiece.
8. Oscillator (1) according to Claim 7, comprising a screw (3p) screwed axially into the end of said stem (3k), the head of said screw (3b) being arranged to enter into contact with a stop (19c) that is as one with said structural element (13), and this is in the event of a shock in an axial direction.
9. Oscillator (1) according to Claim 7, comprising a circlip (3m) or a washer translationally integrated with said stem (3k) and arranged to come into contact with a stop (21a, 19) as one with said structural element (13), this being in the event of a shock in an axial direction.
10. Oscillator (1) according to Claim 7, wherein said stem (3k) comprises a circumferential groove (3n) arranged to cooperate with a stop (21a) that is integrated with said structural element (13), this being in the event of a shock in an axial direction.
11. Oscillator (1) according to Claim 10, wherein said circumferential groove (3n) is constituted by an interstice formed between two rings (3o, 3p) fixed to said stem (3k).
12. Oscillator (1) according to one of the preceding claims, arranged in such a way that said balance (3) performs oscillations having an amplitude of at least 15°, preferably at least 30°, preferably at least 60°, preferably at least 90°.
13. Oscillator (1) according to one of the preceding claims, wherein each elastic system 5 has symmetry of rotation of (720/N)°, N being the number of frames that each elastic system (5) comprises.
14. Mechanical oscillator (1) comprising two oscillators (1) according to one of Claims 1 to 6, arranged head-to-tail and comprising a common balance.
15. Mechanical oscillator (1) according to Claim 16, wherein said common balance consists of two sub-balances that rotate together as one.
16. Oscillator (1) according to one of the preceding claims, wherein at least some of said elastic elements (5b) are made of silicon provided with a layer of silicon oxide on at least some of their surfaces.
17. Timepiece movement comprising an oscillator (1) according to one of the preceding claims.

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