CH719329A2 - Trim element or component for a timepiece or piece of jewelery and its method of manufacture. - Google Patents

Abstract

The invention relates to a covering element for a timepiece or piece of jewelery produced by means of a fiber-reinforced polymer matrix composite material, this covering element comprising on at least one of its faces (2 ) at least one cavity (4) in which is housed an insert made of metallic glass. The invention also relates to a method of manufacturing such a covering element, comprising a step of injecting the metallic glass into the cavity (4) to form the insert.

Description

Technical field of the invention

The present invention relates to a trim element for a timepiece or piece of jewelry. The present invention also relates to a method of manufacturing such a trim element.

Technological background

[0002] Many processes for manufacturing trim elements for timepieces or jewelery such as the back, case middle, bezel or even bracelet links have already been proposed. Among these known manufacturing processes, mention may be made of the manufacturing processes for such trim elements using composite materials obtained by dispersing fibers in a polymer matrix. Examples of these composite materials are, for example, given by polymer matrices in which carbon fibers are dispersed, also known by their Anglo-Saxon name Carbon Fiber Reinforced Polymers or CFRP.

[0003] In use, it has been observed that the covering elements for timepieces or jewelery made using such composite materials regularly suffered from two major defects: poor mechanical resistance to external aggressions and low gloss. . Indeed, the polymer matrices in which the carbon fibers were dispersed proved to be relatively soft and easily scratched. Consequently, producing decorations or reliefs on trim elements obtained by means of such composite materials has proved to be a technical solution that is not very durable. Furthermore, the matte appearance of the casing elements obtained by means of composite materials of the type with a polymer matrix reinforced by means of carbon fibers made the use of such elements for the casing of a high-end watch difficult to envisage. .

[0004] To remedy these problems, alternative solutions have already been proposed. For the realization of the trim elements most exposed to external aggressions such as bezels and crown-type control members or even pushers, metallic or ceramic materials have been used. Other composite materials of the metal matrix and fiber reinforcement type have also been used. More recently, it has also been proposed to produce casing elements for timepieces or jewelery by means of composite materials commonly called "cermet" which consist of a ceramic reinforcement and a metal matrix.

[0005] Even if, from the point of view of the mechanical strength of the covering elements, progress has been achieved thanks to the use of composite materials with a metal matrix and reinforced with fibers or ceramics, the elements of resulting coatings still do not completely satisfy the requirements in the field of watchmaking and jewelery as regards the mechanical strength of their decorations or reliefs. Indeed, the technique usually employed to produce decorations or reliefs on these trim elements consists in combining physical vapor deposition (Physical Vapor Deposition or PVD) and electroforming and only makes it possible to obtain very thin layers. Consequently, although such thin layers are metallic and therefore have a brighter appearance, their thickness is so small that the mechanical resistance of these thin layers to friction and to wear is mediocre.

[0006] Yet another technique for decorating, for example, a wristwatch bezel has been proposed in European patent application EP2315673A1. Briefly summarized, this technique consists in having a bezel, for example made of ceramic, on the surface of which are made recesses to receive, for example, hour markers. An annular bead of amorphous metal is then deposited on the surface of the bezel. Then this bead of amorphous metal is heated to a temperature above its glass transition temperature Tg and pressed so that the amorphous metal penetrates into the hollows. Subsequently, the amorphous metal is cooled and the excess material is removed.

[0007] This technique advantageously makes it possible to obtain covering elements for timepieces with solid decorations that are more resistant to mechanical stress and to wear. This technique which requires the preparation of a sausage of amorphous metal, the heating, the pressing then the cooling of the latter, and finally the elimination of the amorphous metal in excess on the surface of the covering element, is however long. to implement and therefore costly.

Summary of the invention

The object of the present invention is to overcome the drawbacks mentioned above as well as others still by providing trim elements for timepieces or jewelery made of a material which fully meets the requirements in force in the field of watchmaking and jewellery, particularly in terms of mechanical resistance and aesthetics. The present invention also provides a method for the manufacture of such trim elements.

[0009] To this end, the present invention relates to a trim element for a timepiece or piece of jewelery produced by means of a fiber-reinforced polymer matrix composite material, this trim element comprising on one at least of its faces at least one cavity in which is housed an insert made of metallic glass.

According to a special embodiment of the invention, the polymer material used to form the matrix is thermoplastic or thermosetting.

According to another special embodiment of the invention, the polymer material is chosen from the group formed by polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) and polyamide-imide (PAI).

According to yet another special embodiment of the invention, the fibers which reinforce the polymer matrix are chosen from the group formed by glass fibers, carbon fibers and aramid fibers.

According to yet another special embodiment of the invention, the metallic glass used to make the insert is of the solid type (Bulk Metallic Glass or BMG).

According to yet another special embodiment of the invention, the metallic glass used to make the insert contains zirconium or platinum.

[0015] According to yet another special embodiment of the invention, the metallic glass used to make the insert results, apart from the inevitable impurities, from an alloy of zirconium, copper, titanium, nickel, aluminum and niobium.

According to yet another special embodiment of the invention, the metallic glass used to make the insert comprises, in mass percentage, zirconium, copper, titanium, nickel, aluminum and niobium according to the following quantities: – 60 ≤ Zr ≤ 75 – 10 ≤ Cu ≤ 20 – 0 ≤ Ti ≤ 6 – 7 ≤ Ni ≤ 15 – 0 ≤ Al ≤ 8 – 0 ≤ Nb ≤ 6

According to yet another embodiment of the invention, the metallic glass used to make the insert is the Vit106a alloy of composition Zr70Cu13Ni9.9Al3.65Nb3.4 in mass percentage, or Vit105 of composition Zr65. 7Cu15.6Ni11.7Al3.7Ti3.3 in mass percentage.

According to yet another special embodiment of the invention, the metallic glass used to make the insert results, except for inevitable impurities, from an alloy of platinum, copper, nickel and phosphorus.

According to yet another special embodiment of the invention, the metallic glass used to make the insert comprises, in weight percentage, platinum, copper, nickel and phosphorus in the following quantities: - 80 ≤ Pt ≤ 90 – 5 ≤ Cu ≤ 10 – 1 ≤ Ni ≤ 3 – 4 ≤ P ≤ 7

According to yet another embodiment of the invention, the metallic glass used to make the insert is, in mass percentage, given by the composition Pt85Cu7Ni2.3P5.7.

According to yet another special embodiment of the invention, the metallic glass used to make the insert has a glass transition temperature of less than or equal to 350°C.

[0022] According to yet another special embodiment of the invention, the covering element for a timepiece or piece of jewelery is a bottom, a middle part, a bezel, a bracelet link or a clasp.

[0023] The present invention also relates to a method of manufacturing a covering element for a timepiece or piece of jewelery comprising the steps of: - producing the covering element by means of a composite material with a polymer matrix fiber reinforced; – machining in at least one of the faces of the trim element at least one cavity; – bring a metallic glass to its melting temperature; – filling the at least one cavity with metallic glass by injection to form an insert; – carry out, if necessary, finishing operations.

According to a special embodiment of the invention, the cavity is produced by milling.

According to yet another special embodiment of the invention, the finishing operations consist of removing excess material, polishing and/or deburring the insert.

[0026] Thanks to these characteristics, the present invention provides covering elements for timepieces or jewelery which are externally coated with one or more inserts such as hour markers, numerals, a logotype or any other inscription of a technical or fancy nature. These inserts, produced by injection of a metallic glass, are in the form of solid blocks and therefore have excellent mechanical resistance to friction and wear. They also have an appearance which is in accordance with the aesthetic requirements in force in the fields of watchmaking and jewelry. Indeed, given that these inserts are thick, it is possible to subject them to all types of finishing operations to give them a shiny metallic luster. Likewise, these inserts are produced in a single step of injecting a metallic glass, which makes it possible to save considerable time and money, and to guarantee excellent precision in the manufacture of these inserts. For all intents and purposes, it should be noted that, for the purposes of this description, the term "metallic glass" means the range of metallic alloys which have the particularity of being able to be solidified in the at least partially amorphous state, i.e. that is, without a regular arrangement of atoms. Metallic glasses are therefore clearly distinguished from traditional metals which, themselves, crystallize according to ordered structures such as, in particular, simple cubic, centered or centered faces or even hexagonal as well as the variants of these structures. These metallic glasses are generally derived from ternary, quaternary or higher alloys whose ability to solidify in the amorphous state stems from the combination of elements which have between them a dimensional incompatibility such that, from a cooling rate given, the kinetics of solidification is sufficiently slow to make it possible to obtain a disordered solid crystallographic structure. The behavior of this family of materials allows an implementation similar to that of polymeric materials such as injection molding or hot forming. This family of materials has the particular advantage of presenting improved corrosion resistance, high hardness and elastic behavior which limits internal mechanical losses.

Brief description of figures

Other characteristics and advantages of the present invention will emerge more clearly from the following detailed description of an embodiment of a covering element for a timepiece or piece of jewelery in accordance with the invention, this example being given for purely illustrative and non-limiting purposes only in conjunction with the appended drawing in which: - Figure 1 is a top view of a watch bezel according to the invention; – Figure 2 is a sectional view along line B-B of Figure 1.

Detailed description of the invention

The present invention proceeds from the general inventive idea which consists in providing covering elements for a timepiece or piece of jewelery which have mechanical and aesthetic characteristics meeting the requirements required in the field of watchmaking. To this end, the present invention teaches making such trim elements by means of a fiber-reinforced polymer matrix composite material, then providing on the surface of such trim elements at least one cavity in which will be housed a decorative or functional insert made of metallic glass. Thanks to the use of a composite material with a polymer matrix reinforced with fibers, the covering element according to the invention has characteristics of mechanical resistance to wear and aesthetics which make it perfectly suitable for horological applications. On the other hand, the inserts, produced by injection of a metallic glass, form solid studs having a sufficient thickness to allow them to resist external mechanical attacks. Moreover, since these inserts are thick, they easily withstand the finishing operations which will give them the maximum shine and luster. Finally, the production of the inserts is done in a single injection step, which makes it possible to save considerable time and guarantee excellent precision in the manufacture of these inserts.

Designated as a whole by the general reference numeral 1, the bezel shown in Figure 1 is an example of a covering element for a timepiece according to the invention. Other trim elements such as back, middle, links and bracelet clasp can also be envisaged.

According to the invention, the bezel 1 is made using a composite material with a polymer matrix reinforced with fibers. By way of illustrative and non-limiting example only, the polymeric material used to form the matrix is thermoplastic or thermosetting. This polymer material is preferably chosen from the group formed by polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) and polyamide-imide (PAI). This matrix is reinforced by fibers which are preferably chosen from the group formed by glass fibers, carbon fibers and aramid fibers. A plurality of these glasses 1 can be individualized in a plate of composite material of the required thickness.

[0031] By way of example, a covering element such as a bezel 1 in accordance with the invention can be produced by a filament winding process of the SPIDE TP type which has been developed by the center of French mechanical expertise CETIM. Very briefly explained, this filament winding process consists in winding fibers previously impregnated with a polymer material on a mould, for example such as a tube of cylindrical section, in order to obtain a profile. At the same time as these fibers pre-impregnated with polymer are wound around the mold according to a given number of layers and according to an angle with respect to the axis of longitudinal symmetry of the mold which is chosen in particular according to the subsequent use of the parts resulting which will be obtained by cutting the profile, they are heated to a temperature high enough to cause the melting of the polymer with which they are impregnated and pressed against the mould. Finally, the resulting parts are machined conventionally using lathes and milling machines to bring them to their final dimensions.

In the case of the present invention, the glasses 1 are cut from a tubular profile, the inside diameter of which is typically around 30 mm and the outside diameter of which is 45 mm. The tubular profile in which the glasses 1 according to the invention are cut is obtained by winding carbon fibers whose diameter is typically of the order of 5 to 25 μm and which are impregnated with polyetheretherketone (PEEK) whose melting temperature is 341°C. To obtain the desired tubular sections from which the glasses 1 according to the invention will subsequently be cut, the carbon fibers are preferably wound at an angle of 90° perpendicular to the longitudinal axis of symmetry of the tubular section.

[0033] The tubular sections used to produce the glasses 1 in particular are typically composed of approximately 35% PEEK polymer and 65% carbon fibers to within plus or minus 10%. It is therefore understood that the trim elements obtained from these tubular sections contain a large proportion of carbon fibers, which significantly improves their thermal conductivity and allows them to quickly diffuse the heat provided during the injection of the metallic glass. Consequently, although the temperature at which the metallic glass is injected is higher than the melting temperature of the polymer matrix, the glasses 1 will not break down, nor will they deform. It will also be noted that the reduced thickness of the injected inserts combined with the good thermal conductivity of the mold and of the composite material considerably reduce the exposure time of the polymer to a temperature higher than its melting point. Consequently, it is not necessary to take special additional measures to limit the degradation of the polymer during the brief contact with the metallic glass. The visible parts of the composite that have potentially been in contact with the metallic glass will also be removed during the surface finishing operations after leaving the mould.

The bezel 1 comprises on an upper face 2 one or more cavities 4 typically made by milling. According to the invention, these cavities 4 will be filled with a material of the metallic glass type to form inserts 6. Non-limitingly, as shown in Figure 1, these inserts 6 materialize numbers and indexes, for example of triangular or circular. Preferably, these cavities 4 have an undercut angle α of between 5 and 10° to ensure better mechanical strength of the inserts 6.

The metallic glass used to make the inserts 6 is of the solid type (Bulk Metallic Glass or BMG). Preferably, this metallic glass contains zirconium. It is possible, for example, to use an alloy containing, apart from inevitable impurities, zirconium, copper, titanium, nickel, aluminum and niobium. According to a non-limiting example, the metallic glass used to make the insert comprises these materials in mass percentage according to the following quantities: – 60 ≤ Zr ≤ 75 – 10 ≤ Cu ≤ 20 – 0 ≤ Ti ≤ 6 – 7 ≤ Ni ≤ 15 – 0 ≤ Al ≤ 8 – 0 ≤ Nb ≤ 6

An example of a metallic glass containing zirconium which is well suited to the needs of the invention is the Vit106a alloy of composition Zr70Cu13Ni9.9Al3.65Nb3.4 in mass percentage, or Vit105 of composition Zr65.7Cu15.6Ni11. 7AI3.7Ti3.3 in mass percentage.

The metallic glass used to make the inserts 6 can also be platinum-based. It is possible, for example, to use an alloy containing, except for inevitable impurities, platinum, copper, nickel, aluminum and phosphorus. According to a non-limiting example, the metallic glass used to make the insert comprises these materials in mass percentage according to the following quantities: – 80 ≤ Pt ≤ 90 – 5 ≤ Cu ≤ 10 – 1 ≤ Ni≤ 3 – 4 ≤ P ≤ 7

According to yet another embodiment of the invention, the metallic glass used to make the insert is, in mass percentage, given by the composition Pt85Cu7Ni2.3P5.7.

According to yet another special embodiment of the invention, the metallic glass used to make the insert has a glass transition temperature of less than or equal to 350°C.

According to the invention, to form the inserts 6, the cavities 4 are filled with metallic glass by injection. To this end, a metal glass ingot is provided which is placed in a melting chamber and brought to a temperature above its melting point. Once the metallic glass ingot has melted, the metallic glass is injected into a mold in which the bezel 1 is placed and which is arranged so that the metallic glass fills the cavities 4 of this bezel 1. The injection of the metallic glass into the mold in which the bezel 1 is placed can be ensured by mechanical pressure provided by a piston or by gas pressure. The cavities 4 are preferably filled with a slight extra thickness of metallic glass so as to ensure an optimal connection between the bezel 1 and the inserts 6.

After the metal glass has cooled, the bezel 1 is removed from its mold and can be subjected to finishing operations such as the removal of excess material, grinding and/or mechanical or chemical polishing. Any excess thicknesses and burrs are also removed by deburring.

It goes without saying that the present invention is not limited to the embodiment which has just been described and that various modifications and simple variants can be envisaged by those skilled in the art without departing from the scope of the invention. as defined by the appended claims. It will be understood in particular that, in the context of the invention, it is necessary to temporarily bring the metallic glass to its melting temperature so that it can be injected by means of an injection machine.

Nomenclature

[0043] 1 Bezel 2 Upper face 4 Cavities 6 Inserts

Claims (18)

1. Trim element or component for a timepiece or piece of jewelery produced by means of a fiber-reinforced polymer matrix composite material, this trim element comprising on at least one of its faces (2) at least one cavity (4) in which is housed an insert (6) made of metallic glass. 2. Trim element or component according to claim 1, characterized in that the polymer material used to form the matrix is thermoplastic or thermosetting. 3. Trim element or component according to claim 2, characterized in that the polymer material is chosen from the group formed by polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) and polyamide-imide (PAI). 4. Trim element or component according to one of claims 2 and 3, characterized in that the fibers which reinforce the polymer matrix are chosen from the group formed by glass fibers, carbon fibers and fibers of aramid. 5. Trim element according to claim 4 when it depends on claim 3, characterized in that the composite material used is composed of 35% PEEK polymer and 65% carbon fibers to within plus or minus 10% . 6. Trim element or component according to one of claims 1 to 5, characterized in that the metallic glass used to make the insert is of the solid type or Bulk Metallic Glass or BMG. 7. Trim element or component according to claim 6, characterized in that the metallic glass used to make the insert contains zirconium or platinum. 8. Trim element or component according to claim 7, characterized in that the metallic glass used to make the insert results, apart from the inevitable impurities, from an alloy of zirconium, copper, nickel, aluminum and/or or niobium and/or titanium. 9. Trim element or component according to claim 8, characterized in that the metallic glass used to make the insert comprises, in mass percentage, zirconium, copper, titanium, nickel, aluminum and niobium in the following quantities: – 60 ≤ Zr ≤ 75 – 10 ≤ Cu ≤ 20 – 0 ≤ Ti ≤ 6 – 7 ≤ Ni ≤ 15 – 0 ≤ Al ≤ 8 – 0 ≤ Number ≤ 6 10. Trim element or component according to claim 9, characterized in that the metallic glass used to make the insert is an alloy of composition Zr70Cu13Ni9.9Al3.65 Nb3.4 in mass percentage, or an alloy of composition Zr65. 7Cu15.6Ni11.7AI3.7Ti3.3 in mass percentage. 11. Trim element or component according to claim 7, characterized in that the metallic glass used to make the insert comprises, in mass percentage, platinum, copper, nickel and phosphorus in the following quantities: – 80 ≤ Pt ≤ 90 – 5 ≤ Cu ≤ 10 – 1 ≤ Ni≤ 3 – 4 ≤ P ≤ 7 12. Trim element or component according to claim 11, characterized in that the metallic glass used to produce the insert is, in mass percentage, given by the composition Pt85Cu7Ni2.3P5.7. 13. Trim element or component according to one of claims 6 to 12, characterized in that the metallic glass used to make the insert has a glass transition temperature less than or equal to 350°C. 14. Trim element or component according to one of claims 1 to 13, characterized in that the trim element for a timepiece or piece of jewelery is a back, a middle part, a bezel (1), a bracelet link or clasp. 15. Method for manufacturing a trim element or component for a timepiece or piece of jewelery comprising the steps of: – produce the covering element or component using a fiber-reinforced polymer matrix composite material; – machining in at least one of the faces (2) of the covering element or component of at least one cavity (4); – bring a metallic glass to its melting temperature; – filling the at least one cavity (4) with metallic glass by injection to form an insert (6); – carry out, if necessary, finishing operations. 16. Manufacturing process according to claim 15, characterized in that the cavity is produced by milling. 17. Manufacturing process according to claim 16, characterized in that the finishing operations consist of removing excess material, mechanical and/or chemical polishing and/or deburring the insert (6). 18. Manufacturing process according to one of claims 1 to 17, characterized in that the cavities (4) have an undercut angle (a) of between 5 and 10°.