METHOD FOR MANUFACTURING CLOCK COMPONENTS FOR CLOCKS

Description

Scope of the invention

[0001] The present invention relates to a method for manufacturing watch components, and more particularly varnished appliqués intended to be attached to the dial of a timepiece by means of mounting feet to replace all or part of the numerals indicating the hours. Such a method can also be used to make dials or bezels. Background of the invention

[0002] The applied hour markers, or those on secondary dials, are most often made using decals or even screen printing, giving the impression of having been printed. Watchmaking appliques are essential elements of a timepiece, particularly a watch, contributing to its distinctive appearance. Therefore, their execution must be particularly meticulous, highly reproducible, and free of any surface defects. Achieving perfect execution is difficult due to the very small size of these components and their challenging handling. Consequently, the rejection rate can be high. This manufacturing process is even more delicate when the appliques have a coating such as varnish or lacquer to achieve a specific aesthetic effect. In the case of varnished appliques, it is common practice to place the applique on a support and then apply a layer of varnish.It is understood that, in this case, varnish is applied to both the fixture and the support. A joint then forms between the fixture and the support due to capillary action, resulting in a poor appearance, which is unacceptable. Summary of the invention

[0003] One aim of the present invention is to overcome all or part of the disadvantages mentioned above by providing a process for manufacturing high-quality watch appliques while ensuring a perfect surface finish on the visible parts.

[0004] For this purpose, the invention relates to a method for manufacturing wall lights according to the terms of the attached claim 1.

[0005] In accordance with other advantageous variants of the invention: The manufacturing process includes a surface finishing step on the upper surface and the perimeter of the machined appliqué in the base, to ensure a homogeneous application of the varnish layer and eliminate sharp edges that can cause color fading; the finishing is followed by an electrolytic cleaning step of the base to ensure the substrate is clean; the varnish layer has a thickness between 20 µm and 100 µm; the varnish layer is preferably dried at 80°C for 30 minutes, then at 140°C for 60 minutes; the base is made of a metallic material such as brass, aluminum, copper, or precious metal; the adhesive layer is preferably oven-dried at 45°C for 5 hours; the base is removed from the tray in a basket; A surfacing step is performed on the glue layer to obtain a reference surface for dimensional accuracy during machining of the lower face;The machining of the wall light from the underside of the base is carried out under at least one trim element and to dimensions slightly larger than the perimeter of the wall light; At least one foot is formed for the wall light at the same time as the machining from the underside of the base to form the underside of the wall light.

[0006] The invention also relates to a watch comprising at least one appliqué according to the invention.

[0007] Thanks to these characteristics, such a manufacturing process for a watch appliqué makes it possible to obtain appliqués quickly while having a perfect surface finish on the visible parts. Brief description of the drawings

[0008] Other features and advantages of the invention will become more apparent upon reading the following description of a particular embodiment of the invention, given by way of simple illustrative and non-limiting example, and the accompanying figures, among which: THE figures 1 to 6 illustrate different stages of the manufacturing process according to the invention; The figure 7 is a top view of a base whose upper face has been machined; The figures 8 and 9 are respectively cross-sectional views of a base machined from the top face, and of a base that has received a layer of varnish; The Figure 10 is a perspective view of a base machined from the top face. Detailed description of preferred embodiments

[0009] The invention relates to a method for manufacturing a watchmaking appliqué 1.

[0010] By "appliqué" we mean any display or decorative element, intended to be seen by a user, such as a sign, index, number, logo, monogram, or similar, placed on an object, including a dial, flange, plate, bridge, or similar.

[0011] Such an applique 1 usually comprises an upper surface 2 and a perimeter 3 intended to be seen by a user, a lower surface 4 for its support on a dial or structure of a timepiece.

[0012] If this lower surface 4 can be directly glued onto such a dial or structure, it generally has at least one foot 5. Each foot 5 is projecting from this lower surface 4, and more particularly but not exclusively in a particular orientation in space relative to the lower surface 4, for its attachment to such a dial or structure.

[0013] According to the invention, the following steps are carried out successively to manufacture such a wall light 1: a base 10 is made of a metallic material, the base having a top face 11 and a bottom face 12; the top surface 2 and the perimeter 3 of the applique 1 are machined in the base from the top face, with a predefined depth P; the machined base 10 is washed; a layer of varnish 13 is applied to the machined top face of the base 10 so as to cover the top face; the layer of varnish 13 is allowed to dry; a layer of glue 14 is applied, over at least the entire depth of the machining, to the top face of the base 10, the layer of glue 14 being superimposed on the layer of varnish 13, and the glue is allowed to dry; the lower surface 4 and the foot 5 of the applique 1 are machined from the lower face 12 of the base 10 with a depth P' greater than the thickness E of the base less the machined depth P of the upper face, the applique thus formed being held in the layer of glue;The base 10 is immersed in a bath to dissolve the glue and release the fitting 1; the fitting 1 is then packaged for delivery.

[0014] Machining the upper surface 2 and the periphery 3 using a CNC machine can, depending on the case, be carried out on a single tool or on multiple tools, each specific to a particular surface machining operation. The machining can obviously employ various technologies, combined or not, including but not limited to: milling, grinding, electrical discharge machining (EDM), laser cutting, or others.

[0015] Naturally, the upper surface 2 and the periphery 3 of the fitting 1 can be more or less complex, and may include, for example, several elementary surfaces such as flat facets, or other features. Depending on the complexity of the upper surface, machining and / or diamond grinding of the upper surface 2 is carried out using a machining and / or diamond grinding unit that moves along at least 5 axes relative to the base.

[0016] The base 10 is made from a metallic material or metal alloy such as brass, aluminum, or a precious metal. The base 10 also serves as a support for the applique 1 during the manufacturing process until the lower surface 4 and the foot 5 are machined.

[0017] According to a particular feature of the invention, the machining of the upper surface 2 and the periphery 3 of the fitting 1 in the base 10 is carried out from the upper face of the latter, the machining having a predefined depth P. Advantageously, the depth P of the machining is provided to be greater than the final height H of the fitting 1.

[0018] According to a particular feature of the invention, after the upper surface 2 and the perimeter 3 have been made, the machined base 10 is washed by means of an ultrasonic wash, so as to remove all dust and residues related to the machining and to avoid any defects in the varnish layer.

[0019] More particularly, according to a particular feature of the invention, the upper surface 2 and the perimeter 3 of the appliqué 1 machined in the base 10 are brought to a spruce up in order to polish the edges of the appliqué and improve the covering power of the varnish.

[0020] A further washing step is carried out following the polishing; the base is then washed by means of an electrolytic washing process.

[0021] According to one embodiment of the invention, the base can undergo a surface treatment to improve the adhesion of the varnish layer; such treatment could consist of a sandblasting or plasma blasting operation, for example. A further washing step may then be necessary to remove any remaining impurities.

[0022] According to a particular feature of the invention, a layer of varnish 13 is deposited on the machined upper face of the base 10 so as to cover the upper face of the base, and implicitly the upper surface 2 and the periphery 3 of the wall plate 1. The varnish layer is deposited by means of a spraying operation; the base could also be dipped. The varnish layer has sufficient thickness to cover the wall plate; typically, the thickness is between 20 µm and 100 µm.

[0023] Next, this layer of varnish 13 is dried in an oven at 80°C for 30 minutes, then at 140°C for 60 minutes. This two-stage drying process ensures slow and even polymerization, resulting in a more uniform varnish thickness. Of course, the parameters of this drying stage may vary depending on the manufacturer's specifications.

[0024] According to a particular feature of the invention, a layer of adhesive 14 is deposited on the upper face of the base 10, the adhesive layer 14 being superimposed on the varnish layer 13 and covering the upper surface 2 and the periphery 3 of the fitting 1. Advantageously, the adhesive layer 14 is deposited over at least the entire depth of the machining, or even slightly beyond, so as to extend beyond the plane formed by the upper face of the base. Preferably, a water-based adhesive of the Prolaq® type is used to avoid damaging the varnish during the dissolution of the adhesive in a subsequent step.

[0025] The next step is to dry the layer of glue 14 applied; to do this, the glue-coated base is placed in an oven at 45°C for at least 5 hours.

[0026] Once the adhesive layer 14 is dry, an optional leveling step is carried out. The adhesive layer is machined by means of a surfacing, for example, so as to obtain a uniform layer, to accelerate the release of the applique at the end of the process, and to form a flat reference surface for dimensional control when machining the underside. According to a particular feature of the invention, the underside 4 and the foot 5 of the applique 1 are machined by the underside 12 of the base 10. This machining is carried out to a depth P' greater than the thickness E of the base 10 minus the machined depth P of the upper face, i.e. P' > (EP).

[0027] Machining of the applique 1 by the lower face of the base is carried out to dimensions slightly larger than the perimeter 3 of the applique 1 so as to decouple the applique from the base, the applique thus formed no longer being linked to the base 10 and being held only by the layer of glue 14 deposited previously.

[0028] According to a particular feature of the invention, the base is immersed in an aqueous solution to dissolve the adhesive and free the appliqué from the adhesive layer. The base 10 is immersed in the solution in a basket to allow for easy retrieval of the freed appliqué.

[0029] In the case described here, the liquid solution used is an alkaline aqueous solution to dissolve the adhesive. The base 10 is immersed in a series of washing baths at 55°C for 60 minutes to ensure thorough dissolution of the adhesive. Of course, other liquid solutions can be used depending on the adhesive chosen, just as the washing time and the temperature of the aqueous solution can vary depending on the adhesive used.

[0030] Finally, the wall light can be washed again to remove any remaining glue, then dried. The wall light can also be treated with other decorative finishes, such as the application of a luminescent material.

[0031] Finally, the wall light is packaged on a storage pallet in preparation for delivery.

[0032] The invention also relates to a watch comprising at least one appliqué 1 NOMENCLATURE

[0033] 1. Applique, 2. Top surface, 3. Perimeter, 4. Bottom surface, 5. Foot, 10. Base, 11. Top face, 12. Bottom face, 13. Varnish layer, 14. Glue layer, E. Base thickness, H. Applique height, P,P. Machining depth.

Claims

1. Method for manufacturing an applique (1), including an upper surface (2) and the rim (3) intended to be seen by a user, a lower surface (4) for its resting on a dial or a structure of a timepiece and at least one foot (5) protruding from said lower surface (3), the method comprising the following steps according to which: - A base (10) is produced in a metal material, said base having an upper face (11) and a lower face (12); - The upper surface (2) and the rim (3) of the applique (1) are machined in the base from the upper face, with a predefined depth P; - The machined base is washed; - A varnish layer (13) is deposited on the machined upper face of the base so as to cover the upper face, the upper surface (2) and the rim (3) of the applique (1); - The varnish layer (13) deposited is dried at 80°C for 30 min, then at 140°C for 60 min ; - A glue layer (14) is deposited on the upper face of the base (10), over at least the entire machining depth, said glue layer being superimposed on the varnish layer, and the glue is dried; - the lower surface (4) and the foot (5) of the applique (1) are machined via the lower face (12) of the base (10) with a depth P' greater than the thickness E of the base (10) less the machined depth P of the upper face; - The base is plunged into a bath of a liquid solution in order to dissolve the glue (14) and release the applique (1); - The applique is packaged in view of its delivery.

2. Manufacturing method according to claim 1 further comprising the steps of: - Carrying out trimming of the upper surface (2) and of the rim (3) of the applique (1) machined in the base (10); - Carrying out electrolytic leaching of the base (10).

3. Manufacturing method according to claim 1, wherein the varnish layer (13) has a thickness between 20 µm and 100 µm.

4. Manufacturing method according to one of claims 1 to 3, wherein the base (10) is made of a metal material such as brass, aluminium or a precious metal.

5. Manufacturing method according to one of claims 1 to 4, wherein the glue layer (14) is dried in a stove at 45°C for five hours.

6. Manufacturing method according to one of claims 1 to 5, wherein the bath of the base is carried out in a basket.

7. Manufacturing method according to one of claims 1 to 6, wherein a step of surfacing the glue layer is performed in order to obtain a uniform thickness.

8. Manufacturing method according to one of claims 1 to 7, wherein the machining of the applique via the lower face (12) of the base (10) is carried out under said at least one covering element and with dimensions slightly greater than the rim (3) of the applique (1).

9. Manufacturing method according to claim 8, wherein at least one foot (5) is formed for the applique (1) at the same time as the machining via the lower face of the base in order to form the lower face of the applique (1).