CH716645A2 - Process for manufacturing a clothing component for a timepiece or piece of jewelery and clothing component made of a coated material of natural origin. - Google Patents

Abstract

The invention relates to a manufacturing method and a clothing component (100; 100*) for a timepiece or piece of jewelry, which clothing component (100; 100*) comprises at least one part (10) made of a material of natural origin. The method includes the following steps: (i) providing a trim piece (10) made of a material of natural origin; (ii) preparing a first surface (10A), or top surface, of the trim piece (10) to receive an adhesive (15); (iii) applying the adhesive (15) directly or indirectly to the first surface (10A) of the trim piece (10); (iv) joining, via the adhesive (15), of a covering part (20) made of a transparent material, in particular a glass, with the first surface (10A) of the covering part (10); (v) curing the adhesive (15) so as to make the cover piece (20) integral with the trim piece (10); and (vi) machining, in particular by lapping, of a second surface (108), or lower surface, of the trim piece (10) so as to reduce the thickness of the trim piece (10) to a target thickness (W10.1). The clothing component (100) can be a dial made of natural stone or fossilized material.

Description

Description

TECHNICAL AREA

[0001] The present invention relates generally to the field of watchmaking and jewelry, and more particularly to a method of manufacturing a component of clothing for a piece of timepiece or jewelry as well as to a clothing component obtained by this process. This clothing component can in particular be a dial for a timepiece.

TECHNOLOGICAL BACKGROUND

[0002] The manufacture of dials for timepieces constitutes a branch in its own right in the field of watchmaking. A vast majority of dials used in watchmaking are made of metallic material and conventionally comprise a substantially flat and thin support element, which typically bears hour and minute indications as well as various decorative elements which may be stamped, engraved, printed and/or applied to the support element. It is also common to form apertures and other through openings through the dial in order to allow the passage or reveal Indicator Organs or other Mechanical Organs of the watch movement which is conventionally located behind the dial.

[0003] For very high-end timepieces, it is also known to make use of enamelled or hand-decorated dials, as well as dials using materials of natural origin, such as mother-of-pearl or a mineral material from natural stones. These materials of natural origin are very often fragile and difficult to machine, in particular with a view to producing elements as thin as dials, and the use of these materials can generate a great deal of waste because of their fragility. These materials of natural origin may also present imperfections and/or irregularities which are likely to lead to their rejection from a qualitative point of view.

[0004] Swiss patent application No. CH 649 670 G A3 describes a method of manufacturing a component of the clothing of a timepiece comprising a first part made of a non-metallic material that is difficult to machine, such as a dial plate of mineral glass or of a semi-precious stone, permanently bonded to at least one second metal part, which is formed by growth in a galvanic or chemical bath directly on a portion of the lower surface of the first part, at least one layer of thin metallic coating having been formed beforehand on the portion of the lower surface of the first part by deposition of particles in the gas phase. In this context, the dial plate in mineral glass or semi-precious stone is machined beforehand so as to have the required thinness and to be provided with at least one central hole for the passage of the axes of the hands and two parallel main faces which are polished so as to present their final surface condition. In a first stage, this thin dial plate is glued in a recess formed in the bottom of a practical housing in a matrix of plastic material so as to be made integral with this matrix. A coating formed of an electrically conductive metal is then formed over the entire surface of the die housing, including the lower surface of the thin dial plate, according to a process of metallization by vacuum evaporation or by spraying. ions. This coating is made so as to be sufficiently adherent and thick to bond with the thin dial plate and the metal support body which is formed during the subsequent electroforming operation. This electroforming operation is carried out by placing the matrix with the thin dial plate provided with the conductive coating in a galvanic bath capable of causing the deposit of a metal, such as nickel or a noble metal such as gold. , platinum or silver, or even an alloy having the desired properties and characteristics. The metal body which is formed during the galvanic operation has an irregular lower surface, which is machined. The rest of the plastic matrix is then eliminated, so that a composite dial is obtained having the thin dial plate and a metal trim which extends under the thin dial plate and around its periphery, metal trim on the lower surface of which it is still proceeded to the welding of one or more feet to allow the fixing of the dial. It is explicitly mentioned that the thin dial plate made of mineral glass or semi-precious stone may have an extremely thin thickness of the order of 0.2 mm while the trim may have a thickness of the order of 0.15 mm or even less, leading thus to a total thickness of the composite dial of less than 0.4 mm, the usual thickness of dials.

[0005] The process described in Swiss patent application No. CH 649 670 G A3 certainly allows the production of a relatively thin dial, but this process does not bring any particular improvement as regards the manufacture and machining of the plate. thin dial in mineral glass or semi-precious stone as a bezel. The production of such a thin dial plate at a thickness as low as 0.2 mm remains in particular a very difficult challenge to achieve in practice.

[0006]Artificial devices consisting in producing dials made of glass or synthetic stones have also been proposed, for example in Swiss patents Nos. CH 522 247 A and CH 535 983 A or in American patent No. US 3,793,824 A, but these Solutions are in no way satisfactory insofar as there is no longer any question of using natural mineral materials for the manufacture of the dial , but compositions that aim to approach the appearance of natural mineral materials without however managing to match the finesse and elegance of natural mineral materials.

[0007] Solutions are still known which consist in producing dials on the basis of Murano glass (see American patent No. US 5,109,635 A) or vegetable materials, such as wood or vegetable ivory for example (see for example US Patent No. US 5,555,535 A).

[0008]There therefore remains a real need to propose a process for manufacturing a component of clothing for a timepiece or piece of jewelery which is more suitable for allowing reliable machining of materials of natural origin, in particular materials minerals from natural stones or fossilized materials.

DISCLOSURE OF THE INVENTION

[0009] A general purpose of the present invention is therefore to improve the methods of manufacturing clothing components for timepieces or jewelry comprising at least one piece made of a material of natural origin.

[0010] More particularly, an object of the present invention is to provide a solution which ensures better manufacturing efficiency and drastically reduces the risk of waste.

[0011] Even more specifically, an object of the present invention is to provide such a solution which is particularly suitable for handling and machining mineral materials, in particular mineral materials originating from natural stones or fossilized materials, as well as other materials of natural origin which are difficult to machine using conventional methods.

[0012] The present invention responds to these aims by proposing a method of manufacturing a clothing component for a timepiece or piece of jewelry, the characteristics of which are listed in claim 1. More specifically, such a method is provided manufacturing a clothing component for a timepiece or jewelry piece, which clothing component comprises at least one piece made of a material of natural origin, the process comprising the following steps:

(i) supply of a trim piece made of a material of natural origin;

(ii) preparing a first surface, or upper surface, of the trim piece so as to be able to receive an adhesive;

(iii) applying the adhesive directly or indirectly to the first surface of the trim piece;

(iv) joining, via the adhesive, of a covering piece made of a transparent material, in particular a glass, with the first surface of the covering piece;

(v) hardening of the adhesive so as to make the covering piece integral with the covering piece; And

(vi) machining, in particular by lapping, a second surface, or lower surface, of the trim piece so as to reduce the thickness of the trim piece to a target thickness.

[0013] According to a preferred alternative embodiment, the machining (vi) of the second surface of the trim piece is carried out so as to reduce the thickness of the trim piece to a first target thickness, in particular a first target thickness less than or equal to 0.5 mm, and subsequent machining of the second surface of the trim piece is optionally carried out, in a finishing phase, so as to reduce the thickness of the trim piece to a second target thickness less than the first target thickness, in particular a second target thickness less than or equal to 0.2 mm.

[0014] The trim piece can advantageously have an initial thickness greater than 0.5 mm before the machining (vi) of the second surface of the trim piece. In this way, the risk of breakage of the trim piece is considerably reduced.

[0015] As a preference, the coating piece has an initial thickness greater than a target thickness, which initial thickness is preferably greater than or equal to 1 mm, and the method further comprises the following additional steps:

(vii) machining, particularly by lapping, an upper surface of the liner piece so as to reduce the thickness of the liner piece to a target thickness;

(viii) polishing the top surface of the liner piece to present a polished finish; And

(ix) optionally, application or creation of decorative elements on the upper surface of the piece of covering.

[0016] In this context, the target thickness of the coating piece may in particular be less than or equal to 0.15 mm.

Furthermore, the machining (vii) of the upper surface of the covering piece is preferably carried out after the machining (vi) of the second surface of the trim piece. In this respect, the covering piece thus advantageously fulfills the role, during the machining (vi) of the second surface of the trim piece, of support and reinforcement for the trim piece. The reduction of the thickness of the covering part to the desired target thickness can thus be carried out by drastically reducing the risks of breakage of the covering part.

According to an advantageous embodiment of the invention, the method further comprises one and/or the other of the following finishing steps:

- application, on the second surface of the trim piece, of a contrast layer, preferably opaque; And

- production, on at least the second surface of the casing piece, of a trim or structure, preferably metallic, intended for mounting the casing component in the timepiece or jewelry piece.

[0019] In the context of the present invention, the adhesive is preferably an ultraviolet (UV) curing adhesive and the curing step (v) comprises the application of ultraviolet (UV) rays to the first surface of the dressing piece. This exposure to ultraviolet rays (UV) can be carried out without any particular constraint through the piece of coating, provided that the latter is made of a transparent material allowing substantially the entire range of wavelengths necessary for the priming of the process to pass. crosslinking of the adhesive used.

[0020] According to a particularly preferred embodiment, which is implemented in particular in the context of the production of dials for timepieces, the method also comprises an additional machining step consisting in making one or more through openings , such as a central hole or a window, through the trim piece. In this context, it is particularly advantageous for each through-opening to be made in such a way as to partially penetrate the covering piece over a distance greater than a target thickness of the covering piece.

The material of natural origin constituting the trim piece is preferably a mineral material, such as a mineral material from natural stones or fossilized materials, other materials being however possible. In this context, the invention provides considerable advantages in relation to the machining of natural stones or particularly fragile and/or friable fossilized materials, in particular mineral materials presenting machining difficulties in particular because of their cleavage, their fibrous structure, their microcrystalline structure, differences in hardness, their porosity, the presence of cracks or other irregularities and/or an irregular polished finish.

[0022] The material of natural origin constituting the trim piece can alternatively be:

- material of extraterrestrial origin, such as material from undifferentiated meteorites or differentiated meteorites, including chondrite meteorites, achondrite meteorites, iron meteorites, and mixed meteorites;

- a biosynthesized mineral material, such as mother-of-pearl; or

- an organic material, such as wood, vegetable ivory, amber, copal, jet, or mellite.

[0023] With regard to the transparent material constituting the covering piece, it is in particular desirable to use a silica-based glass or a mineral glass, for example a sapphire glass. The use of a silica-based glass proves to be particularly advantageous insofar as the machining of such a glass is relatively easy and that the execution of a polishing of the surface of such a glass makes it possible to to obtain an excellent finish and a high surface quality, without this requiring complex and expensive tools and polishing means. In reality, one result of the implementation of the invention is that the polishing operation is carried out on a surface of the coating part, and not on a surface of the trim part. In other words, the tools and polishing means required must only be adapted to the type of transparent material used as the constituent material of the covering part and are not impacted by the material of natural origin constituting the trim part. .

[0024] The invention advantageously allows the production of clothing components with reduced thicknesses, in particular dials for timepieces having a total thickness less than or equal to 0.4 mm, the usual thickness of dials used in the field of watchmaking.

[0025] There is also claimed, under claim 10, a clothing component for a timepiece or piece of jewelry, in particular a clothing component obtained according to the method of the invention, the clothing component comprising a covering part made of a material of natural origin and a covering part made of a transparent material, in particular a glass, which covering part is secured to a first surface, or upper surface, of the part covering with an adhesive. This clothing component is preferably a dial for a timepiece or an intermediate product used in the manufacture of said dial.

Other aspects of the invention are set out in the remainder of this description.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of the present invention will appear more clearly on reading the following detailed description of embodiments of the invention, which are presented solely by way of non-limiting examples and are illustrated by the appended drawings. Or :

- Figures 1A to 1G are side section views schematically illustrating a succession of manufacturing steps leading to an intermediate product used in the context of the production of a dial for a timepiece, according to one embodiment of the invention;

- Figures 2A to 2E are side section views schematically illustrating a succession of additional manufacturing steps leading, from the intermediate product obtained following the manufacturing steps illustrated in Figures 1A to 1G, to a dial for a timepiece , according to a preferred embodiment of the invention; And

- Figure 3 is a schematic illustration of a dial, in lateral section, obtained according to the method of Figures 1A to 1G and 2A to 2E, which dial is also provided with a structure intended for mounting the dial in a piece of watchmaking.

EMBODIMENTS OF THE INVENTION

[0028] The present invention will be described with reference to various preferred embodiments as illustrated in particular by Figures 1A-G to 3. The invention will be described in the particular context of the production of a dial for a timepiece (and an intermediate product used in the manufacture of said dial), but it is understood that the invention is applicable to the production of any clothing component for a timepiece or piece of jewelery where the clothing component comprises at least least one part made of a material of natural origin.

[0029] The invention will be more specifically described in the context of the production of a dial comprising a trim piece made of a mineral material, such as a mineral material from natural stones or fossilized materials. In this regard, different natural stones or fossilized materials can be considered. The invention brings in particular considerable advantages in relation to the machining of natural stones or particularly fragile and/or friable fossilized materials, in particular mineral materials presenting machining difficulties in particular because of their cleavage, their structure fibrous, their microcrystalline structure, differences in hardness, their porosity; and/or the presence of cracks or other irregularities and/or an uneven polished finish.

[0030] Among the mineral materials presenting such machining difficulties, Your can in particular avoid, in a non-exhaustive manner, Fluorite, Spectrolite, Labradorite, Amethyst, Ruby, Sapphire, Tourmaline, Slate , Rhodochrosite, Calcite, Feldspar, Adularia, Pietersite, CharoTte, Rutilated Quartz, Tiger's Eye, Hawk's Eye, Fire's Eye, Bull's Eye, Seraphinite , Prehnite, Scolecite, Astrophyllite, Specularite Hematite, Mica, Amazonite, Anhydrite (or Angelite), Larimar, Seaweed, Emerald, Sodalite, Native Gold , Pyrite, Bronzite, ZoTsite, Eudialyte, Marble, Granite, Malachite, Turquoise, Lapis Lazuli, Sugilite, Porous Jasper, Chrysoprase, Chrysocolla, Shattuckite, Azurite, Variscite, Opal, and Landscape Jasper. One can add to this list fossilized materials, such as fossils of plants or animals (palm trees, ammonites, dinosaurs, etc.).

[0031] It will however be understood that the invention is applicable by analogy to other materials of natural origin. The material of natural origin constituting the covering part of the clothing component could thus alternatively be:

- material of extraterrestrial origin, such as material from undifferentiated meteorites or differentiated meteorites, including chondrite meteorites, achondrite meteorites, iron meteorites, and mixed meteorites;

- a biosynthesized mineral material, such as mother-of-pearl; or

- an organic material, such as wood, vegetable ivory, amber, copal, jet, or mellite.

[0032] All the materials of natural origin mentioned above potentially present machining difficulties and/or characteristics liable to affect their ability to be used as a decorative material for a component of a timepiece or jewelry piece of clothing. This being said, the present invention offers a solution which makes it possible to a very large extent to overcome these difficulties.

[0033] Figures 1A to 1G are side section views schematically illustrating a succession of manufacturing steps leading to an intermediate product, designated by the reference 100* (see Figure 1G), used in the context of the production of a dial for a timepiece, according to one embodiment of the invention. Figures 2A to 2E are views in side section schematically illustrating a succession of additional manufacturing steps leading, from the intermediate product 100*, to a dial for a timepiece, designated by the reference 100 (see Figure 2E). Figure 3 is a schematic illustration of a dial 100, in lateral section, obtained according to this process, which dial is also provided with a structure 30 intended for mounting the dial in a timepiece.

[0034] Figures 1A-G to 3 are not necessarily to scale and the thicknesses and proportions of the various component parts of the intermediate product 100* and the dial 100 have been accentuated in order to allow a better understanding of the invention.

Figure 1A schematically shows a side view of a material of natural origin, designated by the reference 10 *, in this case a block (or carrot) of a mineral material. In the particular context of the manufacture of a dial for a timepiece, it is typically a block of material 10* obtained by coring, namely a block of essentially cylindrical shape with irregular faces at each end, as schematically illustrated in Figure 1A.

[0036] A suitable portion of the block of material 10* is cut, for example by sawing, so as to extract a trim piece 10 whose thickness W10.0 is such that the structural integrity of the material remains assured. In the example shown, a disc of material is debited by sawing along two substantially parallel cutting planes

so that the resulting trim piece 10 (here again raw) essentially has two opposite faces 10A, 10A* that are substantially planar.

[0037] By way of illustration, the thickness W10.0 (or "initial thickness") of the covering part 10 is greater than 0.5 mm. Certain materials are however likely to be too fragile to be debited in such a form , and it may in this respect be necessary to abstain from sawing a disk of material as illustrated. debilitate the trim piece 10. It may also be necessary to stabilize the material of natural origin beforehand, for example by applying or impregnating a resin.

[0038] According to the invention, a preliminary step in the manufacturing process consists in preparing a first surface 10A, or upper surface, of the trim piece 10, as schematically illustrated by FIG. 1B. In the specific context of manufacturing a dial for a timepiece, this preparation step can in particular be carried out by lapping so as to form a first substantially planar surface 10A. In the example illustrated, the procedure is likewise lapping the opposite surface 10A*, so that this opposite surface 10A* is also substantially flat and parallel to the first surface 10A.

[0039] The purpose of this step is to prepare the first surface 10A so as to be able to receive an adhesive. Polishing of the first surface 10A is not necessary, it being noted that a certain degree of residual asperity of the first surface 10A will promote better adhesion of the adhesive.

[0040] Once the first surface 10A of the trim piece 10 has been duly prepared, an adhesive 15 is applied to the first surface 10A of the trim piece 10, as illustrated in FIG. 1C. This is preferably an adhesive 15 with ultraviolet (UV) curing, namely an adhesive which, once subjected to UV radiation, initiates a crosslinking process leading to the curing of the adhesive.

[0041] Once the adhesive 15 has been applied to the first surface 10A of the covering part 10, one then proceeds to join a covering part 20 made of a transparent material, in particular a glass, with the first surface 10A, provided with the adhesive 15, of the trim piece 10, as illustrated in Figure 1D. It is important, during this joining step, to avoid the formation of air bubbles which could remain trapped in the interface between the covering part 20 and the trim part 10.

[0042] In this case, the constituent glass of the coating piece 20 is advantageously a silica-based glass, but other glasses, in particular mineral glasses, are potentially possible, such as a sapphire glass. More generally, any other suitable transparent material could be used. In the context of the invention, however, the use of a silica-based glass proves to be particularly advantageous and greatly facilitates the manufacturing process. Furthermore, silica glasses are conventionally available in the form of plates having an already calibrated thickness. By way of example, the initial thickness W20.0 of the covering piece 20 is, at this stage of production, greater than or equal to 1 mm. Lower initial thicknesses are possible, but this can potentially lead to greater glass brittleness.

[0043] It may be noted at this stage that it matters little whether the adhesive 15 is applied directly to the first surface 10A of the trim piece 10 or to the inner surface 20B of the covering piece 20. the adhesive 15 can thus be applied directly to the first surface 10A of the trim piece 10 or indirectly, by applying the adhesive 15 first of all to the lower surface 20B of the covering piece, before applying the trim piece. coating 20 on the trim piece 10. It is also perfectly possible to use, if necessary, a dual-component adhesive where a first component of the adhesive is applied to the first surface 10A of the trim piece 10 and wherein a second component of the adhesive is applied to the lower surface 20B of the liner piece 20.

[0044] In the illustrated example, curing of adhesive 15 is initiated by subjecting adhesive 15 to ultraviolet radiation, which radiation initiates the process of cross-linking of adhesive 15, thereby resulting in curing of the adhesive. adhesive 15 so as to make the covering part 20 integral with the covering part 10. Ultraviolet radiation can be applied to the first surface 10A of the covering part 10 through the covering part 20, as illustrated schematically in Figure 1E. This exposure to ultraviolet light can be carried out without any particular constraint through the coating piece 20, provided that the latter is made of a transparent material allowing the entire range of wavelengths necessary to initiate the crosslinking process to pass. adhesive used.

The crosslinking process of the adhesive 15 is virtually immediate and the curing step of the adhesive 15 does not require an extended time. Depending on the type of adhesive used, it may however be necessary to leave the composite assembly consisting of the covering part 10 and the covering part 20 to rest, united by the adhesive 15, for a period sufficient for complete curing. adhesive.

[0046] Once the adhesive 15 has hardened, further machining is carried out, in particular by lapping, of a second surface 10B, or lower surface, of the trim piece 10 so as to reduce the thickness of trim piece 10 to a target thickness. In the illustrated preferred embodiment, this Operation is carried out in two stages, namely a first stage, such as illustrated in Figures 1F and 1G, where the machining of the second surface 10B of the trim piece 10 is first of all operates so as to reduce the thickness of the trim piece 10 to a first target thickness W10.1 (see FIG. 1G). This first target thickness W10.1 is preferably less than or equal to 0.5 mm.

[0047] In a second step which will be discussed below with reference to Figures 2A to 2E, a subsequent machining of the second surface 10B is additionally operated so as to further reduce the thickness of the trim piece 10 to a second thickness. target W10.2 less than the first target thickness W10.1 (see Figures 2B and 2C). This second target thickness W10.2 is preferably less than or equal to 0.2 mm.

In the context of the invention, one could consider that the machining of the second surface 10B of the trim piece 10 is operated in a single step, or in more than two steps as needed.

[0049] Returning to Figure 1G, it will be understood that the steps discussed with reference to Figures 1A to 1G lead to an intermediate product, designated by the reference 100*, which must still undergo a certain number of additional steps. , Feiles as illustrated by Figures 2A to 2E, before arriving at the dial 100 desired. That said, the intermediate product 100 * consists of the composite assembly formed of the covering part 10 and the covering part 20, united by the adhesive 15, is much easier to handle as well as to transport because the presence of the coating element 20. Indeed, the intermediate product 100* has at this stage a sufficient thickness (for example of the order of 1.5 mm or more) which greatly facilitates its handling and drastically reduces the risk of breakage of the covering part 10, this covering part 10 being de facto integral with the covering part 20. The covering part 20 thus offers the advantage of providing support and reinforcement for the covering part 10 .

It should be noted that the stages of Figures 1A to 1G and Figures 2A to 2E will not necessarily be carried out on the same site and by the same person. The steps described with reference to Figures 1A to 1G will normally be carried out by a preparer having the expertise and knowledge necessary for the preparation, handling and machining of the material of natural origin constituting the trim piece 10 , whereas the steps which will now be discussed with reference to Figures 2A to 2E will typically be carried out by a dial maker having the expertise and knowledge necessary to manufacture and finish the dial itself. It will be understood that the dial maker will carry out machining operations of and in the covering part 10, operations which therefore require, in the case in point, additional competence in the field of machining natural stone dials .

[0051] As already mentioned above, the very structure of the intermediate product 100* ensures optimum transfer from the preparer who works the stone to the dial-maker who proceeds to the finishing stages of the actual dial.

[0052] Figure 2A schematically shows a side view of the intermediate product 100* of Figure 1G in which an additional machining step has been carried out consisting in making through openings 10a, 10b through the dressing 10. It is a question here in particular of a central hole 10a which is conventionally made in order to allow the passage of organs indicating a watch movement (for example the axes and barrels of hour and minute hands) as well than a window 10b for displaying another indication, for example a date display. These are purely illustrative examples, and any through openings made through the trim piece 10 could, if necessary, fulfill any other desired function. It is obviously understood that the shape, the arrangement, as well as the dimensions of the through openings will essentially depend on the particular design of the desired dial and the indications that one wishes to display on the dial or in relation to the dial.

In the illustration of Figure 2A, it can be noted that the through openings 10a, 10b are made in such a way as to partially penetrate the covering part 20. The penetration distance of the through openings 10a, 10b is here chosen so as to be greater than a target thickness W20.1 of the covering piece 20 (see in particular FIGS. 2D and 2E), namely the target thickness W20.1 of the covering piece 20 of the finished clothing component.

[0054] The additional machining step carried out on the trim piece 10 can, if necessary, include the performance of additional machining operations, in particular on the lower surface 10B of the trim piece 10, such as the machining of recesses intended to receive the dial feet 30 as illustrated by way of example in Figure 3.

[0055] Once the step of additional machining of the covering part 10 has been carried out, the second step of reducing the thickness of the covering part 10 already mentioned above is preferably carried out. This involves reducing the thickness of the trim piece 10 from the first target thickness W10.1 to the second target thickness W10.2, as illustrated schematically by FIGS. 2B and 2C. This operation makes it possible in particular to remove any burrs or surface defects present on the second surface 10B of the trim piece 10 resulting from the previous machining operation. This Operation also makes it possible to reduce the thickness of the casing part 10 to the desired final thickness and to guarantee the desired surface condition on the back of the dial.

[0056] Once this operation has been performed, machining is then carried out, in particular by lapping, of an upper surface 20A of the covering piece 20 so as to reduce its thickness to a target thickness W20.1, as illustrated in Figures 2D and 2E. This target thickness W20.1 is preferably less than or equal to 0.15 mm. The upper surface 20A of the coating piece is also polished so as to present the desired polished finish P.

[0057] It can be noted that the use of a silica-based glass proves to be particularly advantageous insofar as the machining of such a glass is relatively easy and that the execution of the polishing of the surface of such a glass makes it possible to obtain an excellent finish and a high surface quality, without this requiring complex and expensive tools and polishing means. As already mentioned, a result of the implementation of the invention is that the polishing operation is carried out on the upper surface 20A of the piece of coating 20, and not on a surface of the piece.

of covering 10. In other words, the tools and polishing means required must only be adapted to the type of transparent material used as the constituent material of the covering part 20 and are not impacted by the constituent material of natural origin of the trim piece 10. For a given type of glass, one can therefore guarantee a predetermined polished finish P which is independent of the nature of the trim piece 10.

[0058] Once the polishing of the upper surface 20A of the covering part 20 has been carried out, one can then proceed to the application or the creation of decorative elements on the upper surface 20A of the covering part 20, by example the affixing of hour and minute indications and/or other decorative elements.

According to a variant of the invention, one could, if necessary, consider applying decorative elements between the covering part 20 and the trim part 10 before the joining of these parts by means of the adhesive. 15 in addition to or replacement of the decorative elements on the upper surface 20A of the covering part

[0060] It is preferable that the machining of the upper surface 20A of the covering piece 20 be carried out only after the definitive machining of the second surface 10B of the covering piece 10. This in fact ensures that the the composite assembly can be maintained in an adequate manner, on the surface of the covering part 20, not yet polished, during the final lapping of the covering part 10. The machining and the final polishing of the covering part 20 does not present in this respect, there is no particular difficulty and can be operated on after final running in of the trim piece 10.

[0061] Once all the additional operations have been carried out, discussed in the context of the example embodiment illustrated in FIGS. 2A to 2E, one then has a dial 100 that is almost finished.

[0062] Additional finishing operations are still possible.

An additional finishing operation could for example consist of the application, on the second surface 10B of the trim piece 10, of a contrast layer, preferably opaque. This may in particular be judicious or desirable depending on the degree of transparency of the trim piece 10, once reduced to its final target thickness.

[0064] Another additional finishing operation, more usual, consists of the production, on at least the second surface 10B of the covering piece 10, of a trim or structure, preferably metallic, intended for mounting the dial 100 in the timepiece. It is a question here in particular of creating one or more feet on the back of the dial 100, as illustrated in Figure 3 where two feet 30 are visible. Such a filling can for example be formed according to the teaching of Swiss patent application No. CH 649 670 G A3 discussed in the preamble. Individual feet 30, as illustrated in FIG. 3, can also be formed directly on the second surface 10B of the trim piece 10 by applying, for example, an adhesion film, for example metallic, serving as a base for the fastener. (for example by welding) of the feet 30 as mentioned for example in British patent GB 2 052 113 B.

The invention advantageously allows the production of a dial 100 whose total thickness W100 is less than or equal to 0.4 mm, the usual thickness of dials used in the field of watchmaking.

It will generally be understood that various modifications and/or improvements obvious to those skilled in the art can be made to the embodiments described in the present description without departing from the scope of the invention defined by the appended claims. For example, although the invention has been presented in the particular context of the manufacture of a dial for a timepiece, the invention can be applied to any other component of clothing for a timepiece or jewelry. The clothing component could thus serve only as a facing or decoration for a timepiece or piece of jewelry, without necessarily having the purpose of enabling the display of the time or of another indication of a timepiece movement. The fact remains that the application to the manufacture of dials for timepieces remains a major and particularly advantageous application of the invention.

LIST OF REFERENCE SIGNS USED IN THIS DESCRIPTION AND IN THE DRAWINGS

[0067]

10 piece of trim made of a material of natural origin (for example a mineral material from natural stones or fossilized materials)

10* block of raw material, for example block obtained by coring

10A first surface (upper surface) of the trim piece 10

10A* lower surface of trim piece 10 raw (before machining)

10B second surface (lower surface) of trim piece 10 (after machining)

10a through opening made through the covering part 10/central hole for the passages of the hour and minute indicators of a watch movement

10b through opening made through the trim piece 10 / window

adhesive (eg UV curing adhesive)

20 piece of coating made of a transparent material, in particular a glass (for example a glass based

silica)

20A upper surface of coating part 20, after machining and polishing

20B lower surface of the piece of covering 20 made integral with the first surface 10A of the piece of ha

beading 10 using adhesive 15

30 trim or structure intended for mounting the clothing component 100 / feet of dial

Claims (10)

100 100* W10.0 W10.1 W10.2 W20.0 W20.1 W100 P dial for timepiece (clothing component) intermediate product used in the manufacture of dial 100 initial thickness (before machining) of the trim piece 10 (first) target thickness of trim piece 10 (second) target thickness of trim piece 10 initial thickness (before machining) of the coating part target thickness of the coating part 20 dial thickness 100 polished finish of the upper surface 20A of the liner part 20 Claims 1. A method of manufacturing a clothing component (100; 100*) for a timepiece or jewelry piece, which clothing component (100; 100*) comprises at least one piece (10) made in one material of natural origin, characterized in that the process comprises the following steps: (i) supply of a trim piece (10) made of a material of natural origin; (ii) preparing a first surface (10A), or upper surface, of the trim piece (10) so as to be able to receive an adhesive (15); (iii) applying the adhesive (15) directly or indirectly to the first surface (10A) of the trim piece (10); (iv) joining, via the adhesive (15), of a covering part (20) made of a transparent material, in particular a glass, with the first surface (10A) of the covering part (10); (v) hardening of the adhesive (15) so as to make the covering piece (20) integral with the covering piece (10); And (vi) machining, in particular by lapping, of a second surface (108), or lower surface, of the trim piece (10) so as to reduce the thickness of the trim piece (10) to a target thickness (W10.1; W10.2). 2. The method according to claim 1, characterized in that the machining (vi) of the second surface (10B) of the trim piece (10) is operated in such a way as to reduce the thickness of the piece by covering (10) at a first target thickness (W10.1), in particular a first target thickness (W10.1) less than or equal to 0.5 mm, and in that a subsequent machining of the second surface (1 OB) of the trim piece (10) is optionally carried out, in a finishing phase, so as to reduce the thickness of the trim piece (10 ) to a second target thickness (W10.2) less than the first target thickness (W10.1), in particular a second target thickness (W10.2) less than or equal to 0.2 mm. 3. The method according to claim 1 or 2, characterized in that the trim piece (10) has an initial thickness (W10.0) greater than 0.5 mm before the machining (vi) of the second surface (1 OB ) of the trim piece (10). 4. The method according to any one of the preceding claims, characterized in that the coating piece (20) has an initial thickness (W20.0) greater than a target thickness (W20.1), which initial thickness (W20. 0) is preferably greater than or equal to 1 mm, and in that the method further comprises the following additional steps: (vii) machining, in particular by lapping, of an upper surface (20A) of the covering piece (20) so as to reduce the thickness of the covering piece (20) to the target thickness (W20.1 ); (viii) polishing the top surface (20A) of the liner piece (20) to present a polished finish (P); And ' (ix) optionally, application or creation of decorative elements on the upper surface (20A) of the covering part (20), the target thickness (W20.1) of the covering piece (20) being in particular less than or equal to 0.15 mm, the machining (vii) of the upper surface (20A) of the covering piece (20) being preferably carried out after the machining (vi) of the second surface (1 OB) of the covering part (10). 5. The process according to any one of the preceding claims, characterized in that it further comprises one and/or the other of the following finishing steps: - application, on the second surface (1 OB) of the trim piece (10), of a contrast layer, preferably opaque; And - realization, on at least the second surface (1 OB) of the trim piece (10), of a trim or structure (30), preferably metallic, intended for mounting the clothing component (100) in the piece watchmaking or jewelry. 6. The method according to any preceding claim, characterized in that the adhesive (15) is an ultraviolet (UV) curing adhesive and that the curing step (v) comprises the application of ultraviolet (UV) on the first surface (10A) of the trim piece (10). 7. The process according to any one of the preceding claims is characterized in that it also comprises an additional machining step consisting in making one or more through openings (10a, 10b), such as a central hole (10a) or a window ( 10b), through the trim piece (10), and in that each through-opening (10a, 10b) is preferably made in such a way as to partially penetrate the covering piece (20) over a distance greater than a target thickness (W20.1) of the covering piece (20). 8. The method according to any one of the preceding claims, characterized in that the material of natural origin constituting the trim piece (10) is: - a mineral material, such as a mineral material from natural stones or fossilized materials; - material of extraterrestrial origin, such as material from undifferentiated meteorites or differentiated meteorites; - a biosynthesized mineral material; Or - an organic material. 9. The method according to any one of the preceding claims, characterized in that the transparent material constituting the coating piece (20) is a silica-based glass or a mineral glass, for example a sapphire glass. 10. A clothing component (100; 100*) for a timepiece or jewelry piece, in particular a clothing component (100; 100*) obtained according to the method of any one of the preceding claims, the component clothing (100; 100*) comprising a covering piece (10) made of a material of natural origin and a covering piece (20) made of a transparent material, in particular a glass, which covering piece ( 20) is secured to a first surface (10A), or upper surface, of the trim piece (10) by means of an adhesive (15), the clothing component (100; 100*) preferably being a dial (100) for a timepiece or an intermediate product (100*) used in the manufacture of said dial (100).