SHOCK ABSORBER BEARINGS FOR A CLOCK

Description

technical field

[0001] The present invention relates to the field of watchmaking. More particularly, it concerns a shock-absorbing bearing comprising a bushing and a counter-pivot independent of each other. State of the art

[0002] Documents CH 255756 and CH 278334 describe shock-absorbing bearings in which the drilled stone, which acts as a cushion, is suspended in a floating manner within its housing by means of an elastic element. This elastic element is held in position by the support of the lug that carries the counter-pivot. The counter-pivot is subjected to the effect of a return spring that holds it in place and ensures the axial positioning of the elastic element.

[0003] The positioning of the elastic element, and therefore of the bearing, is consequently dependent on the jewel. In the event of a significant axial or diagonal impact that lifts the counter-pivot and the jewel, the elastic element is no longer held in position by the return spring and the jewel, either relative to the housing or the counter-pivot. It is therefore possible for the elastic element to shift unintentionally, either relative to the housing or the counter-pivot. Consequently, the correct positioning of the drilled stone is not guaranteed at all times.

[0004] Documents CH 333250, CH 243388, CH 333591, and CH 296070 disclose bearings in which at least the drilled stone is supported in the housing by means of a one-piece rubber or elastomer bushing. The choice of material for the elastic element in these documents is clearly unsatisfactory for long-term bearing use. Rubber and elastomers typically degrade over time and due to unavoidable contact with oil, necessitating their periodic replacement. Furthermore, these materials require a simple, one-piece bushing design, which severely limits the possibilities for optimizing the mechanical properties of the elastic element.A modern shaped elastic organ, having an outer part, a central part, and at least one elastic element connecting the two, has significantly more freedom compared to a simple ring in terms of its design, and therefore its mechanical properties according to all degrees of freedom.

[0005] Document CH 245429 describes a bearing comprising a spring element that supports the drilled stone within a central ring. The spring element has bosses located at the ends of four elastic arms. These bosses are positioned in a groove such that they exert a force on the bottom of the groove. The radial positioning of the drilled stone is highly sensitive to the tolerances of the four arms, and its assembly is difficult because it requires the arms to be clipped into the groove almost simultaneously. Furthermore, this groove is used to position the spring element axially.

[0006] Document CH 313812 discloses a bearing in which a setting carrying the two stones is supported by an elastic ring with outward and inward bulges. This elastic ring exhibits very little perpendicular flexibility to its plane, and given that the single setting also carries the counter-pivot, axial displacement occurs between the housing and the elastic element and / or between the elastic element and the setting during an axial impact. Specifically, either the setting will slide against the inner bulges, or the outer bulges will slide against the housing wall, or both. This sliding will cause wear on the bulges and / or the setting and / or the housing, and therefore the long-term positioning of the drilled stone is not guaranteed.

[0007] Document CH 292136 describes yet another embodiment of a bearing, in which the elastic element consists of a wire spring. This wire spring is held and axially positioned in the housing by being wedged between a shoulder and a bushing pressed into the housing above the wire spring. This bearing is complex and difficult to disassemble for maintenance due to this pressed-in bushing.

[0008] US patent 2,700,273 describes a bearing in which a circular ring is located at the bottom of the housing. A beveled wall of the setting rests against this ring to radially, but not axially, position the setting. In the event of a radial impact, the beveled wall slides on the ring, causing the setting to move against a spring. The setting is therefore not fixed to the ring and is free to move relative to it, which does not guarantee proper positioning of the drilled stone.

[0009] Document FR 2020047 describes a bearing integrated into a racket and mounted on the rooster via the latter. This bearing is complex and appears very difficult, if not impossible, to implement while maintaining an acceptable tolerance for the position of the drilled stone. Therefore, ensuring the correct positioning of the drilled stone is challenging.

[0010] Finally, document CH 262967 describes a bearing without a chaton in which an elastic element carrying the drilled stone, a ring-shaped spacer, and a counter-pivot stone are stacked in a housing and held there by the forces of a spring ring applied axially to the upper face of the counter-pivot stone. These elements are simply placed one on top of the other in the housing with some clearance, which does not guarantee their correct positioning at all times.

[0011] The aim of the invention is to provide shock-absorbing bearings in which the aforementioned defects are at least partially overcome. Disclosure of the invention

[0012] More specifically, the invention relates to a shock-absorbing bearing for a watch component according to a first independent claim. This bearing comprises a hollow housing including a wall and a base, and an opening in said base of the housing, intended to receive a pin of an axle, such as the axle of a moving part, for example a balance staff.

[0013] Disposed within the housing is an elastic element comprising an outer portion, adapted for positioning the elastic element within the housing and having, for example, substantially the shape of a ring; a central portion comprising a bearing situated opposite said opening; and at least one elastic element connecting said outer portion to said central portion. The bearing includes, as is generally known, a hole for receiving the extension of the axis. The bearing may be formed by a separate piece fixed to the central portion, such as a drilled stone made of synthetic gemstone, a ring of metallic material, or a silicon-based material (such as mono- or polycrystalline silicon, its oxide, nitride, or carbide, also mono- or polycrystalline), or may be formed from the same material as the central portion.

[0014] A counter-pivot is located in the housing opposite the bearing and is subjected to a force exerted by a return spring that tends to push the counter-pivot towards the bottom of the housing, thus maintaining it in its rest position. The counter-pivot can be a synthetic gemstone, a metallic element, or a silicon-based material (such as mono- or polycrystalline silicon, its oxide, nitride, or carbide, also mono- or polycrystalline).

[0015] The outer part of the elastic element is held in the housing by friction generated by elastic forces exerted between said outer part and the housing wall. This friction may result from pressure displacement under elastic conditions, or from deformations of additional elastic elements such as elastic tabs or fingers, or similar components.

[0016] According to the invention, either a chaton that supports said counter-pivot, or the counter-pivot itself in the case of a bearing without a chaton, comprises a first bearing surface arranged to be in contact with said outer part of the elastic element in the bearing's rest position. Furthermore, the material of said elastic element is selected from crystalline or amorphous metals, ceramics, or a silicon-based material.

[0017] Consequently, the elastic element self-positions within the housing, independently of the return spring force. In the event of a significant impact, the risk of the elastic element shifting or tilting relative to the housing is minimized, thus improving the bearing's positioning relative to the housing. Furthermore, the initial bearing surface ensures proper axial positioning of the counter-pivot relative to the elastic element and therefore to the bearing.

[0018] Advantageously, a radial gap exists between the kitten, if present, and the wall of the dwelling.

[0019] Advantageously, a radial clearance exists between the counter-pivot and the socket, if present. The lateral wall of the socket adjacent to the counter-pivot can be cylindrical or conical, a conical wall particularly facilitating the mounting of the counter-pivot in the socket.

[0020] Each of the aforementioned games simplifies the assembly and disassembly of the bearing.

[0021] Advantageously, the seat, if present, includes a second bearing surface arranged to be in contact with the central part of the elastic element when the bearing is in its rest position. This second bearing surface is separated from the first bearing surface by an annular groove located between the first and second bearing surfaces. This groove preferably has a radial width sufficient to ensure that at least one elastic element remains free relative to the seat. This arrangement provides a greater axial contact distance between the central hole 11a of the bearing 11 and the pivot of the shaft. Furthermore, the second bearing surface acts as a stop to prevent any risk of the bearing and the counter-pivot coming into contact during a very severe impact.

[0022] Alternatively, the kitten is not present, the counter-pivot or elastic element being configured in such a way that it also performs the functions of the kitten. In the first case, the counter-pivot itself comprises a first bearing surface arranged to be in contact with the outer part of the elastic element in the bearing's rest position. The counter-pivot may also comprise a second bearing surface arranged to be in contact with the central part of the elastic element in the bearing's rest position, separated from the first bearing surface by an annular groove located between the first and second bearing surfaces.In the same way as in the case of a realization with a kitten, this arrangement ensures a greater axial distance of contact between the central hole 11a of the pad 11 and the pivot of the axis, and the second bearing surface serves as a stop to avoid any risk of the pad and the counter-pivot coming into contact during a violent shock.

[0023] In the event that no kitten is present, a radial play may exist between the counter-pivot and the wall of the housing, which simplifies the assembly and disassembly of the bearing.

[0024] In another embodiment, the outer part of the elastic member may include at least one thrust element projecting in the opposite direction to the bottom, i.e., projecting from the upper surface of the outer part. This thrust element is adapted to axially position the counter-pivot when the bearing is in its rest position. This positioning may be achieved, where appropriate, either by directly positioning a counter-pivot without a bushing, or by positioning a bushing that carries a counter-pivot. Thus, another embodiment with or without a bushing is proposed, which offers the advantages of the invention.

[0025] Advantageously, the bottom of the housing includes a shoulder arranged to be in contact with the outer part of the elastic element. Consequently, the elastic element and the central part of the elastic element are not in contact with the bottom of the housing, and this applies to all embodiments described above. Brief description of the drawings

[0026] Further details of the invention will become clearer upon reading the following description, made with reference to the attached drawings in which: Fig. 1 is a perspective view of a shock-absorbing bearing according to the invention; Fig. 2 is a plan view of the shock-absorbing bearing of the figure 1 ; Fig. 3 is a vertical cross-sectional view parallel to axis AA of the figure 2 ; Fig. 4 is a vertical cross-sectional view parallel to the BB axis of the figure 2 ; Figs. 5 and 6 are views similar to figures 3 and 4respectively, which represent an alternative shock-absorbing bearing according to the invention; Figs. 7 and 8 are also views similar to figures 3 and 4 respectively, which still represent an alternative shock-absorbing bearing according to the invention; Fig. 9 is a cut-off perspective view and the figures 10-11 are cross-sectional views of another alternative shock-absorbing bearing not forming part of the invention; and Fig. 12 is a vertical cross-section of yet another variant of an alternative bearing according to the invention. Method of embodiment of the invention

[0027] THE figures 1 to 4 illustrate a shock-absorbing bearing according to the invention in its rest position. The geometric axis of the bearing is defined as being perpendicular to the intersection of axes AA and BB shown on the figure 2 The "radial" and "axial" directions are therefore understood in relation to the axis of the bearing.

[0028] This bearing, as is generally the case, includes a housing 3 in which the bearing components are housed. In the illustrated example, this housing 3 is formed in a cup intended to be attached to a component of a clock movement, such as a mainplate or bridge. Alternatively, the housing 3 can be formed directly in the body of a mainplate or bridge by machining it directly. The housing is delimited by a base 3a, extending in a plane perpendicular to the axis of the bearing 1, and by a substantially cylindrical wall 3b, which extends perpendicularly to the plane of the base 3a and parallel to the axis of the bearing 1.

[0029] The housing 3 includes, as is generally known, a central opening 5 in its bottom 3a, substantially coaxial with the housing, and in which a tenon of a pivot axis (not illustrated), such as a balance shaft, is intended to take place.

[0030] The base 3a of the housing 3 includes a shoulder 7 against which an elastic element 9 is positioned. This elastic element comprises an outer portion 9a substantially ring-shaped, a central portion 9c also substantially ring-shaped, and at least one (preferably two, three, or four, larger numbers not excluded) elastic element 9b connecting the outer portion to the central portion 9c. The shapes and configurations of the elastic elements 9b may be various, such as those disclosed in documents EP 2 206 022, CH 704739 on behalf of the applicant. The material of the elastic organ is chosen from crystalline or amorphous metals such as steel and nickel, ceramics such as sapphire, alumina, ruby ​​etc., or a silicon-based material, i.e. mono- or polycrystalline silicon, its oxide, its nitride, its carbide or similar, all these compounds also being monocrystalline or polycrystalline.

[0031] Unlike the bearings disclosed in documents CH 255756 and CH 278334 cited in the preamble, the elastic element 9 is held elastically within the housing. The outer portion 9a can be positioned either by pressing with elastic deformation or by additional elastic elements such as tabs or fingers extending outwards from the outer portion 9a and bearing against the cylindrical wall of the housing 3. The outer portion 9a bears elastically against the housing wall, which generates mutually complementary forces on the wall and on the outer portion 9a in a substantially radial direction. These forces generate friction sufficient to secure these components together during the operation of the bearing.

[0032] At the center of the central portion 9c of the elastic element 9 is a bearing 11, here illustrated as a pierced stone 11 with a central hole 11a for receiving the end of the shaft. As shown, this pierced stone 11 is typically made of ruby, but can also be formed from a metal ring, or obtained from a silicon-based material (such as mono- or polycrystalline silicon, its oxide, nitride, or carbide, also mono- or polycrystalline), or similar, and is pressed, welded, or bonded into a corresponding opening in the central portion. Alternatively, such a pierced stone 11 can be integrated into the central portion 9c by growth of the material in the central portion 9c. The central portion 9c can have a continuous or discontinuous circular geometry (for example, by being split or formed of several bumps), or a continuous or discontinuous polygonal geometry.

[0033] Alternatively, the bearing may have come from a single piece with the central part 9c, that is, formed with a hole in the central part 9c. In such a case, the central part 9c adjacent to the hole 11a is considered to be the bearing 11, which is not necessarily a separate piece from the central part 9c.

[0034] With the elastic element 9 positioned on the shoulder 7 of the base 3a of housing 3, and neither the elastic element(s) 9b, nor the central part 9c, nor the bearing 11 in contact with the base 3a of housing 3, the illustrated bearing is of the so-called "floating" or "non-triggering" type. Alternatively, the elastic element(s) 9b and / or the central part 9c and / or the bearing 11 may be in contact with the base 3a, either on a flat face or on a conical face, as is generally known, particularly in the bearings developed by Mr. Gérard Erismann during the 1930s and 1940s.

[0035] The bearing 1 according to the invention also includes a counter-pivot 13, arranged opposite the bearing 11, and intended to come into contact with the end of the shaft in the event of an axial shock. As illustrated, the counter-pivot 13 is a conventional type of counter-pivot stone, made of ruby, but can also be made of metal, silicon-based material (such as mono- or polycrystalline silicon, its oxide, nitride, or carbide, also mono- or polycrystalline), or similar materials.

[0036] The counter-pivot 13 is mounted in a suitable seat 15d provided in a chat 15 with radial clearance between these two parts. Alternatively, the counter-pivot 13 could also be glued, welded, pressed, or crimped into the chat 15.

[0037] The cat-o'-lantern 15 is positioned in the housing 3 with radial clearance and includes a first bearing surface 15a shaped such that, in the bearing's rest position, it comes into contact with the outer part 9a of the elastic element 9 under the action of a return spring 17. The return spring comprises tabs 17a that bear against the counter-pivot 13 in an axial direction. The mounting of the return spring 17 in notches 21 provided for this purpose in the housing 3 is well known, and it goes without saying that other shapes of elastic elements are also possible. These aspects therefore need not be described in further detail.

[0038] The fact that the elastic element 9 is held elastically in the housing 3, and not by a force supplied by the return spring 17 and transmitted to the outer part 9a via the lug 15, allows the positioning of the pad 11 to be decoupled from that of the counter-pivot 13. Indeed, the elastic element 9 is held in the correct position on its own. In the event of a strong axial impact that would lift the counter-pivot 13 and possibly also the lug 15, the elastic element 9 therefore remains in position against the shoulder 7, without risk of displacement, rotation, or misalignment of the elastic element 9.

[0039] Advantageously, the seat 15 includes a second bearing surface 15b shaped such that it contacts the central part 9c of the elastic element 9 when the bearing is in its rest position. This variant provides, compared to the variant in which said second bearing surface 15b is absent (see below), a greater axial contact distance between the central hole 11a of the drilled bearing 11 and the pivot of the moving part's axis. Furthermore, the second bearing surface 15b acts as a stop to prevent any risk of the two stones 11, 13, or even the bearing 11 and the counter-pivot 13, coming into contact during a very severe impact. Furthermore, the elastic elements 9b remain free at all times, and cannot come into contact with either the bottom 3a of the housing 3, or with the kitten 15: the kitten is provided with an annular groove 15c for this purpose.

[0040] In the illustrated example, the elastic organ has a constant height, and consequently the first bearing surface 15a and the second bearing surface 15b of the kitten are substantially in the same plane. If the elastic organ 9 does not have a constant height, the position of the second bearing surface 15b relative to the first bearing surface 15a can be adjusted accordingly.

[0041] However, as illustrated in the figures 5 and 6 in views similar to those of figures 3 and 4 Respectively, it is not mandatory for the kitten 15 to have this second bearing surface 15b – removing this feature would allow for better recentering of the pad 11 after a radial impact. The bearing 1 remains improved compared to those in documents CH 255756 and CH 278334. In these figures, only the reference symbols mentioned in the text relating to these figures have been shown in order to avoid cluttering them. The figure 12 also illustrates a method of implementation similar to that of the figures 3 and 4 , which differs from the latter in that the seat 15d in which the counter pivot 13 is positioned includes a conical side wall, which narrows towards the bottom 3a of the housing 3. This conicity facilitates the placement of the counter pivot 13 in the kitten.

[0042] THE figures 7 and 8 illustrate in views similar to those of figures 3 and 4 respectively, yet another variant of the invention in which no kitten 15 is present. Again, in these figures, only the reference numerals mentioned in the text in connection with these figures have been shown in order to avoid cluttering the figures.

[0043] In the method of implementation of figures 7 and 8The elastic element 9 comprises, projecting from the upper surface of its outer portion 9a (i.e., the surface on the side of the counter-pivot 13, and therefore opposite the bottom 3a of the housing 3), at least one positioning stop 9d for axially positioning the counter-pivot 13. This positioning stop 9d may be in the form of a stud or one or more straight or curved grooves, against which the counter-pivot 13 is brought by the return spring 17 when the bearing is in its rest position. The positioning stop 9d may, for example, be an annular groove. Furthermore, the positioning stop 9d may or may not be integral with the outer portion 9a of the elastic element 9.

[0044] Therefore, this embodiment features a simple counter-pivot 13 and does not include a chaton. The bearing shown in these figures thus has fewer components than the embodiment of figures 1 to 4and is more economical to implement. However, the same principle also applies to an embodiment featuring a chaton, particularly in the case where the chaton is a simple ring, circular or split, flush-mounted around the counter-pivot 13.

[0045] Further modifications to the levels of figures 1-8 without departing from the scope of the invention as defined by the claims.

[0046] For example, the counter-pivot 13 and the kitten 15 of the embodiment of the figures 1 to 4 may come from a single piece in the event that no play between these components is deemed necessary, the shape of the chaton 15, and particularly that of the first and second bearing surfaces 15a, 15b and that of the groove 15c, being taken up in the shape of the counter pivot 13. This variant is not illustrated.

[0047] The wall of housing 3 does not necessarily have to be cylindrical, but may have protrusions and / or notches, which could influence the direction of the forces exerted between the outer part 9a and the wall of housing 3.

[0048] THE figures 9-11 further illustrate a variant of a shock-absorbing bearing 1 which is not the subject of the invention, the figure 9 being a cropped perspective view, the Figure 10 being a section corresponding to said cut, and the figure 11 being a section perpendicular to said section. Again, in these figures, only the reference symbols mentioned in the text relating to these figures have been shown in order to avoid cluttering the figures.

[0049] Level 1 of figures 9-11 differs from those of figures 1-8in that the elastic organ 9 is no longer held directly in the housing 3, but is fixed in the socket 15. This fixing can be achieved by means of the friction generated by elastic forces exerted between said outer part 9a and the wall of the socket (chasing, elastic elements, as mentioned above), or by gluing, welding, brazing, pinning or similar.

[0050] To this end, the kitten 15 includes an inner shoulder 15e, fitted into the lower part of its inner perimeter 15f. As illustrated in the figures 9 to 11, This inner shoulder is annular, but other shapes are also conceivable depending on the shape of the outer part 9a of the elastic organ 9. In the case of fixing by gluing, welding, pinning or similar, the inner shoulder 15e is superfluous and can be removed.

[0051] The inner shoulder 15a has a height less than the thickness of the outer part 9a, such that the kitten 15 does not come into contact with the bottom 3a of the housing 3. Therefore, the outer part 9a remains in contact with the shoulder 7 of the bottom 3a of the housing 3. However, it is also possible that said height is greater than said thickness, or that these two are equal.

[0052] To allow the kitten 15 to move in response to impacts, the rim 17b of the return spring 17 is not in contact with the kitten or the counter-pivot 13 in its rest position. However, this rim 17b can act as an axial stop to limit the axial displacement of the kitten 15 during a strong impact.

[0053] In the illustrated case, the counter-pivot 13 is driven, welded, brazed, or glued into the upper part of the chaton 15, which is tubular in shape, but it is also possible for the counter-pivot 13 to be positioned against a suitable shoulder, as is the case in the figures 1 to 6 with or without play between these two elements.

[0054] It goes without saying that, similarly to the case described above in connection with the level of figures 1 to 4 The counter-pivot 13 and the kitten 15 can be made of a single piece of material, and therefore be monobloc, the counter-pivot 13 consequently taking the shape of the counter-pivot 13 - kitten 15 assembly as can be seen in the figures 9 to 10 This reduces the number of bearing parts when manufactured using micromachining.

Claims

1. Shock-absorbing bearing (1) for a timepiece, comprising: - a housing (3) comprising a wall (3b) and a bottom (3a); - an opening (5) in said bottom (3a), said opening (5) being designed to receive a pivot shank; - an elastic member (9) comprising an outer portion (9a) adapted to position the elastic member (9) within the housing (3), a central portion (9c) comprising a bearing (11, 11a) situated opposite said opening (5), and at least one elastic element (9b) connecting said outer portion (9a) to said central portion (9c); - an endstone (13) situated in the housing (3) opposite the bearing (11, 11a); - a return spring (17) arranged to exert a force on the endstone (13) in order to push it towards said bottom (3a) of the housing (3); wherein the outer portion (9a) of the elastic member (9) is held in the housing (3) by frictional forces generated by elastic stresses exerted between said outer portion (9a) and the wall (3b) of the housing (3), wherein either a setting (15) supporting said endstone (13), or the endstone (13) itself, comprises a first bearing surface (15a) arranged to be in contact with said outer portion (9a) of the elastic member (9) when the bearing (1) is in its rest position, and characterised in that the material of said elastic member (9) is selected from crystalline or amorphous metals, ceramics or a silicon-based material.

2. Shock-absorbing bearing (1) according to claim 1, wherein said bearing comprises said setting (15), and wherein there is a radial clearance between the setting (15) and the wall (3b) of the housing (3).

3. Shock-absorbing bearing (1) according to one of claims 1 and 2, wherein said bearing comprises said setting (15), and wherein there is a radial clearance between the endstone (13) and the setting (15).

4. Shock-absorbing bearing (1) according to claim 3, wherein the side wall of the setting adjacent to the endstone (13) is cylindrical or conical.

5. Shock-absorbing bearing (1) according to one of claims 1 to 4, wherein said bearing comprises said setting (15), and wherein the setting (15) comprises a second bearing surface (15b) arranged to be in contact with said central portion (9c) of the elastic member (9) in the rest position of the bearing (1), an annular groove (15c) being situated between said first bearing surface (15a) and said second bearing surface (15b), said groove (15c) having a radial width sufficient for said at least one elastic element (9b) to remain free relative to the setting (15).

6. Shock-absorbing bearing (1) according to claim 1, wherein said endstone (13) comprises said first bearing surface (15a), and wherein there is a radial clearance between the endstone (13) and the wall (3b) of the housing (3).

7. Shock-absorbing bearing (1) according to one of claims 1 and 6, wherein said endstone (13) comprises said first bearing surface (15a), and wherein said endstone 13) comprises a second bearing surface arranged to be in contact with said central portion (9c) of the elastic member when the bearing (1) is in the rest position, said endstone (13) comprising an annular groove situated between said first bearing surface and said second bearing surface, said groove having a radial width sufficient for said at least one elastic element (9b) to remain free relative to the endstone (13).

8. Shock-absorbing bearing (1) according to claim 1, in which the outer portion (9a) of the elastic member (9) comprises at least one stop element projecting in the direction opposite to said bottom (3a), said stop element being adapted to axially position said endstone (13) when the bearing (1) is in the rest position.

9. Shock-absorbing bearing (1) according to any one of claims 1 to 8, wherein the bottom (3a) of the housing (3) comprises a shoulder (7) arranged to be in contact with the outer portion (9a) of the elastic member (9).

10. Shock-absorbing bearing (1) according to any one of claims 1 to 9, wherein said outer portion (9a) is substantially ring-shaped.