Device for attaching a timepiece glass or dial

Abstract

The present invention relates to a fastening device (10) for a watchmaking structure (2) equipped with at least one fastening means (20), for a component (1) having at least one through hole (11), having at least one fastening element (3) dimensioned to be inserted into the hole (11) with a non-zero radial clearance, this fastening element (3) having a complementary fastening means (30) arranged to cooperate in a complementary manner with a fastening means (20) of the structure (2), this device (10) having at least one spacer (4) arranged to be inserted between the component (1) and the fastening element (3) and to maintain them at an axial and radial distance from each other, and to support an axial force resulting from the cooperation between the fastening means (20) and the complementary fastening means (30) when the fastening element (3) is in its position closest to the structure (2),the component (1) is at a distance from said structure (2) when said fastening element (3) is in its position closest to said structure (2).

Description

Scope of the invention

[0001] The invention relates to a watch comprising at least one structure equipped with at least one fastening means, at least one component comprising at least one through hole, and at least one such device for fastening said at least one component to said at least one structure.

[0002] The invention relates to the field of assembling watch components onto structural elements, and more particularly to the fixing of fragile components or components sensitive to certain stresses. Background of the invention

[0003] In watchmaking, some components are difficult to fix to other structural elements, due to their fragility, their sensitivity to tightening stresses, or their nature, especially when these components are made of natural materials such as mother-of-pearl, or similar.

[0004] This is particularly the case with dials, which are often very thin, may be enameled, or have a decoration that does not withstand deformations of the support well, or be made of sapphire or another transparent material that does not withstand screwing, pressing, or fixing feet well.

[0005] The traditional methods for fixing dials are as follows: dial mounting on one of the outer diameters of the movement; fixing by feet of dials locked in the movement in different ways; fixing of the dial by screw screwed into the movement.

[0006] These known methods cannot be applied to sapphire dials, due to the nature of the material and its shaping capabilities: it is difficult to remove a sapphire dial without breaking it, it is difficult to make feet for such a dial of this type, and the stresses generated by screws risk breaking the dial.

[0007] In addition, sapphire dials have wider manufacturing tolerances than traditionally manufactured dials, which also limits conventional assembly methods.

[0008] The same issue applies to components other than dials: crystals, particularly sapphire crystals, sapphire components in mysterious mechanisms, acoustic membranes, gongs, and similar devices. Document JPS5832489 describes a component positioned at a distance from a structure when attached to that structure. Furthermore, document JPS5692980 describes the attachment of a component to a structure by means of a screw that engages with a threaded hole, which constitutes the means of attachment to the structure. Summary of the invention

[0009] The invention proposes various solutions for fixing such delicate fixing components, and in particular sapphire dials, allowing the holding and positioning of such a component or sapphire dial by screws despite the resistance constraints and manufacturing tolerances mentioned above.

[0010] These components can be drilled, with fairly wide tolerances, and the drilled holes can be used for their retention.

[0011] The invention relates, again, to a reversible fixing device for such components, and makes it possible to avoid the mandatory use of gluing, or welding or brazing or laser welding or crimping, or other processes leading to damage to the component during possible disassembly.

[0012] For this purpose, the invention relates to a watch, according to claim 1. Brief description of the drawings

[0013] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, with reference to the attached drawings, where: there figure 1 represents, schematically and in cross-section, a part of a watch, comprising a case with a structure onto which a sapphire dial is fixed by means of screws, according to a first variant close to the invention; the dial has a hole into which the screw is inserted with play, a spacer formed by an O-ring seal is inserted between the screw body, the screw head, and the edge of the hole in the dial; the figure 2 represents, in a similar way to the figure 1 , the detail of a second variant close to the invention, where the spacer is made up of a shim, here a conical elastic washer, bearing against the screw body, the screw head, and a counterbore that the dial has at the opening of its hole; the figure 3represents, in a similar way to the figure 2 , the detail of a third variant close to the invention, where the spacer consists of a plastic tube compressed between the screw head and the structure; the figure 4 represents, in a similar way to the figure 2 , the detail of a first embodiment of a fourth variant of the invention, where the spacer is a metal spacer bonded to the dial or the screw; this metal spacer here comprises a collar bearing on a counterbore in the dial at its upper face at the opening of the hole, as well as under the screw head, and on a counterbore in the structure; the dial here rests on the structure; the figure 5 represents, in a similar way to the figure 4, the detail of a second embodiment of this fourth variant of the invention, where the collar rests under the dial, and under the screw head and on a counterbore that forms part of the structure at its upper face, on which the dial rests; the figure 6 represents, in a similar way to the figure 4 , the detail of a third embodiment of the fourth variant of the invention, similar to the first embodiment, but where the collar rests, on the one hand, under the screw head, and on the other hand, on the structure; the dial is at a distance from both the screw head and the structure; the figure 7 represents, in a similar way to the figure 5 , the detail of a fourth embodiment of the fourth variant of the invention, similar to the second embodiment, but where the collar rests, on the one hand, under the screw head, and on the other hand, on a counterbore of the structure; the dial is at a distance from both the screw head and the structure; the figure 8 represents, schematically and in cross-section, a portion of the dial including one of its screw holes; the figure 9 is a block diagram representing a part of a watch, comprising the structure, a dial, and such a fastening device for attaching this dial to the structure. Detailed description of preferred embodiments

[0014] The invention relates to a fastening device 10 for a component 1 having at least one through hole 11 on a structure 2 equipped with at least one fastening means 20. This device 10 includes at least one fastening element 3, which is dimensioned to be inserted into such a hole 11 with a non-zero radial clearance. This fastening element 3 includes a complementary fastening means 30, which is arranged to cooperate in a complementary manner with a fastening means 20 of the structure 2. Naturally, the same component 1 may have holes 11 of different diameters; the device 10 may then include different fastening elements 3, each adapted to the dimension of the hole 11 with which it cooperates, with sufficient but not excessive clearance.

[0015] According to the invention, this device 10 comprises at least one spacer 4, which is arranged to be inserted between the component 1 and the fixing element 3, and to maintain them at an axial and radial distance from each other, and to support an axial force resulting from the cooperation between the fixing means 20 and the complementary fixing means 30 when the fixing element 3 is in its position closest to the structure 2.

[0016] More specifically, and as can be seen on the figures 1 to 3 The spacer 4 is mounted freely between component 1 and the fixing element 3.

[0017] More specifically, and as can be seen on the figure 3 , the spacer 4 is mounted freely between component 1, structure 2, and fixing element 3.

[0018] More specifically, the spacer 4 is attached to component 1 or to the fastener 3. The figures 4 to 7illustrate configurations where the spacer 4 can be fixed, in particular by gluing or similar, to the structure 2 or to the fixing element 3.

[0019] More specifically, and as can be seen on the figures 1 and 2 The spacer 4 is axially elastic. This can also be the case for the figure 3 if an elastic material is chosen to make the tube forming the spacer 4.

[0020] In another achievement of the figure 3 , the material of spacer 4 is plastic deformation: the proper fixing of component 1 is ensured only during tightening, but any disassembly requires the removal of spacer 4 and its replacement with a new spacer for reassembly.

[0021] More specifically, and as can be seen in particular on the figure 1 , spacer 4 is radially elastic.

[0022] In particular, spacer 4 has at least one O-ring seal; it is therefore elastic axially and radially.

[0023] More specifically, and as can be seen on the figure 2 , the spacer 4 includes at least one conical or cup-shaped or fan-shaped elastic washer, or of the "Belleville" washer type or of the "Schnorr" washer type or similar.

[0024] More specifically, as seen on the figure 3 , spacer 4 includes at least one resin or polyester tube.

[0025] More specifically, and as can be seen on the figures 4 to 7 The spacer 4 is axially rigid; it is therefore the one that absorbs all the axial force due to the screwing of the screw onto the structure, no stress is passed on to component 1.

[0026] More specifically, spacer 4 includes at least one metal tube.

[0027] More specifically, the spacer 4 comprises at least one metal tube fitted with a collar, which is arranged to separate component 1 on one side from structure 2 or fastening element 3 on the other. figure 4 shows such a collar cooperating with a counterbore that component 1 has at the outlet of its bore 1, and the figure 5 shows such a collar cooperating with a similar counterbore that then comprises structure 2.

[0028] Component 1 is at a distance from structure 2 when the fastener 3 is in its position closest to structure 2. figures 6 and 7illustrate such an example, where component 1 is not flush with either the end of the collar or the end of the tube opposite the collar: a first gap E1 is guaranteed between component 1 and structure 2, and a second gap E2 is guaranteed between component 1 and a bearing surface 39 that comprises the fixing element 3, in this case the lower surface of the screw head in this particular example.

[0029] More specifically, in an unillustrated variant, component 1 is separated from structure 2 by a spacer wedge.

[0030] The fixing element 3 is a screw whose thread constitutes the complementary fixing means 30, and is arranged to cooperate in a complementary manner with a tapped hole constituting the fixing means 20 of the structure 2.

[0031] More specifically, component 1 is a watch crystal.

[0032] More specifically, component 1 is a watch face.

[0033] More specifically, the dial is made of sapphire or mother-of-pearl.

[0034] More specifically, component 1 is a watch acoustic membrane.

[0035] More specifically, component 1 is a watch chime or gong.

[0036] More specifically, these components 1 are dials, and the figures illustrate this particular and non-limiting application of the invention. The assembly of dials 1 made of fragile material with a structure 2 is achieved by means of screws 3, and the invention lies in the addition of at least one spacer 4, notably in a particular arrangement in the form of a ductile element, ensuring the retention and positioning of the dial 1, the screw 3 being itself locked onto the structure 2. The axial force resulting from the interaction between the fastening means 20 and the complementary fastening means 30 when the fastening element 3 is in its position closest to the structure 2 then corresponds to the complete tightening of a screw, constituting the fastening element 3, into a threaded hole in the structure, forming the fastening means 20. This complete tightening is understood, as the case may be, as tightening to a predetermined nominal torque, or as tightening to its full travel.

[0037] A first variant close to the invention is illustrated by the figure 1The fixing element 3 consists of a special screw supporting an O-ring, forming the spacer 4, and ensuring the axial and radial positioning of the dial 1. The stresses applied to the dial 1 are limited by the compression capacity of the O-ring. Its position within the holes 11 of the dial 1 ensures the holding forces along the radial and axial axes. It should be noted that the locking force of the screw 3 is exerted by the screw's bearing surface on the structure 2; only the O-ring 4 is in contact with the sapphire dial 1.The lower face 12 of the dial 1 bears on the upper face 22 of the structure 2; the upper face 19 of the dial 1 is at a distance from the lower surface 39 of the head of the screw 3; the body of the screw 3 has a centering 31 which cooperates with a counterbore 21 of the structure 2; the bore 11 has an inner edge 14 which is advantageously rounded so as not to damage the O-ring seal 4; the upper surface 49 of the O-ring seal 4 is in contact with the lower surface 39 of the head of the screw 3.

[0038] A second variant close to the invention is illustrated by the figure 2The fixing element 3 consists of a special screw supporting a shim that axially holds the dial 1 in position. The stresses applied to the dial 1 are limited by the compressive capacity of the shim. Radial play exists. The locking force of the screw 3 is achieved, as before, by the screw's bearing surface on the structure 2. Only the shim 4 is in contact with the sapphire dial 1; its inner diameter 491 bears on the body of the screw 3. The dial 1 is held axially but not radially, unless a shouldered counterbore 18 is present at the opening of the bore 11, as on the... figure 2 limits the crushing of spacer 4.

[0039] A third variant close to the invention is illustrated by the figure 3The assembly is carried out with a spacer 4, which is a ring or tube made of polyester elastomer, resin, or a similar material. The fastening element 3 is also a special screw that supports a ring, typically made of elastomer, which secures the dial 1 in position axially and radially. This ring is deformed by compression when the screw is tightened. The stresses applied to the dial 1 are limited by the compression capacity of the ring 4. As explained above, this deformation of the ring may or may not be reversible, depending on the material chosen. The locking force of the screw 3 is achieved by the screw's bearing surface on the structure; only the gasket is in contact with the sapphire crystal. The tube can advantageously be pre-assembled onto the screw 3 to facilitate handling.The upper face 19 of the dial 1 is kept away from the lower surface 39 of the head of the screw 3; the upper edge 492 of the tube 4 is in contact with this same lower surface 39.

[0040] A fourth variant is illustrated by the figures 4 to 7This is achieved through various implementations. These are assemblies with at least one metal spacer 4, preferably bonded. The dial 1 (or the screw 3) may include at least one ring, and / or at least one insert, and / or at least one spacer. These added elements are attached, in particular but not exclusively, by bonding and arranged to absorb the stresses generated by the screw. The dial 1 is constructed so as not to be in contact with the structure 2, specifically with an initial gap E1 of approximately 0.03 mm, in order to avoid / limit the stresses associated with this statically indeterminate assembly. The deformation of the end of the spacer 4, which is in contact with the structure 2, also limits these stresses. The locking force of the screw 3 is achieved by the screw 3 bearing against the ring 4 and the structure 2; only the geometric stresses of the components are transferred to the sapphire dial 1. Here again, the dial 1 is axially restrained. On the figure 5A metal spacer 4 is glued to the dial 1 on its upper side, fixing it axially and radially without constraining it. On the figure 6 , a metal spacer 4 is glued onto the dial 1 on the lower side of the dial 1, and fixes it axially and radially.

[0041] It is thus possible to assemble dials 1 made of fragile material with screws 3, with the addition of a spacer 4 which is a glued support element ensuring the holding and positioning, the screw 3 being locked onto the structure 2 by means of the glued element.

[0042] The invention further relates to a watch 100 comprising at least one structure 2 equipped with at least one fastening means 20, at least one component 1 comprising at least one through hole 11, and at least one such fastening device 10 for fastening this at least one component 1 to this at least one structure 2.

[0043] The invention offers definite advantages.

[0044] In the particular case of dials, illustrated by the figures, the 24-hour Cyclotest type tests, 8-hour Chappuis type tests, and acceleration tests under 500 g, confirm the dial's resistance without breakage, and the absence of degradation due to friction.

[0045] These particular assembly means according to the invention make it possible to assemble and position fragile components or sapphire dials by means of screws without risking their breakage.

Claims

1. A watch (100) comprising at least one structure (2) equipped with at least one fastening means (20), with a component (1) comprising at least one through hole (11), and at least one device (10) for fastening the component (1) to the structure (2), said device (10) comprising at least one fastening element (3) dimensioned to be inserted into said hole (11) with non-zero radial slack, said fastening element (3) comprising a complementary fastening means (30) designed to engage in a complementary manner with a said fastening means (20) on said structure (2), said device (10) comprising at least one spacer (4) designed to be inserted between said component (1) and said fastening element (3) and to keep them at an axial and radial distance from each other, and to withstand an axial stress resulting from the engagement between said fastening means (20) and said complementary fastening means (30) when said fastening element (3) is in its position closest to said structure (2), the component (1) being at a distance from said structure (2) when said fastening element (3) is in its position closest to said structure (2), said fastening element (3) being a screw with a threading consisting of said complementary fastening means (30) and being designed to engage in a complementary manner with a tapping consisting of said fastening means (20) on said structure (2).

2. The watch (100) according to claim 1, characterised in that said spacer (4) is loosely fitted between said component (1) and said fastening element (3).

3. The watch (100) according to claim 2, characterised in that said spacer (4) is loosely fitted between said component (1), said structure (2), and said fastening element (3).

4. The watch (100) according to claim 1, characterised in that said spacer (4) is fastened to said component (1) or to said fastening element (3).

5. The watch (100) according to any of claims 1 to 4, characterised in that said spacer (4) is axially resilient.

6. The watch (100) according to any of claims 1 to 5, characterised in that said spacer (4) is radially resilient.

7. The watch (100) according to claim 5, characterised in that said spacer (4) comprises at least one conical or cup-shaped or fan-shaped resilient washer.

8. The watch (100) according to claim 5 or 6, characterised in that said spacer (4) comprises at least one O-ring.

9. The watch (100) according to claim 5 or 6, characterised in that said spacer (4) comprises at least one resin or polyester tube.

10. The watch (100) according to any of claims 1 to 4, characterised in that said spacer (4) is axially non-distortable.

11. The watch (100) according to claim 10, characterised in that said spacer (4) comprises at least one metallic tube.

12. The watch (100) according to claim 10, characterised in that said spacer (4) comprises at least one metallic tube fitted with a collar arranged to separate said component (1), on one hand, from said structure (2) or said fastening element (3) on the other hand.

13. The watch (100) according to any of claims 1 to 12, characterised in that said component (1) is a watch glass.

14. The watch (100) according to any of claims 1 to 12, characterised in that said component (1) is a watch dial.

15. The watch (100) according to claim 14, characterised in that said dial is made of sapphire or of mother of pearl.

16. The watch (100) according to any of claims 1 to 12, characterised in that said component (1) is an acoustic membrane for a watch.

17. The watch (100) according to any of claims 1 to 12, characterised in that said component (1) is a watch timbre or a watch gong.

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