HK1206439B - Brazed bimetal external part of a timepiece - Google Patents

Description

Brazed bimetallic timepiece exterior part

Technical Field

The invention concerns a method for manufacturing an external part of a timepiece.

The invention also relates to the use of this method for making an external part, which is a jaw of a watch case.

The invention also relates to an external part of a timepiece.

The invention also relates to a timepiece, in particular a wristwatch, comprising at least one external component as described above.

Background

The exterior parts of timepieces are often made of precious metals, such as gold or platinum, in order to ensure excellent corrosion resistance. However, these metals are dense and, therefore, timepieces, especially watches, appear very heavy to the user and are also very expensive. Materials such as gold are malleable and their mechanical properties are general, which often means that gold alloys need to be selected which are more stable in terms of changes in appearance over time, but which are also more susceptible to corrosion.

Japanese patent application JP 60228666a in the name of CITIZEN describes brazing of gold or gold alloy components on a titanium or titanium alloy substrate and uses a titanium nitride surface obtained by nitriding to prevent gold from penetrating into the titanium.

Japanese patent application JP 56105881a in the name of SEIKO describes brazing of gold or gold alloy components to copper alloy substrates.

European patent application EP 1439434a1 in the name of CITIZEN discloses brazing components to titanium substrates.

Disclosure of Invention

The invention proposes an alternative to the use of an external part of a timepiece made entirely of precious metal.

To this end, the invention relates to a method for manufacturing an external part of a timepiece or piece of jewelry, characterized in that:

-providing a metal substrate made of a first material, said first material being titanium or a first titanium alloy;

-providing at least one metallic cover plate made of a second material comprising a second metal selected from gold, platinum, palladium or silver and/or a second alloy comprising at least gold or platinum or palladium or silver, said at least one cover plate having a thickness greater than or equal to 0.5 mm;

-brazing the at least one cover plate to the base to form a bi-metal blank;

-then shaping the bi-metal blank so as to give the structural component its final form.

According to a particular feature of the invention, the brazing operation is carried out with a brazing filler metal (brazing material) chosen to form a braze (braze) between the first material and the second material.

The invention also relates to the use of the method for manufacturing an external part, which is a jaw of a watch case, wherein:

-cutting a titanium substrate with cuts and through holes from a thin plate or sheet so as to form a ladder structure with lateral bearing surfaces connected by cross beams;

-bending the crossbar to form a stirrup (U, fork);

-brazing two gold caps on the lateral bearing surfaces of the substrate to form a bimetallic blank;

-cutting said bi-metal blank into segments;

-shaping the segments by deformation so as to form the jaw seats.

The invention also relates to an external part for a timepiece, characterized in that it is made of a bimetallic material, comprising a metal base made of a first material comprising titanium or a first titanium alloy, and at least one metal cover made of a second material comprising a second metal chosen from gold, platinum, palladium or silver, and/or comprising a second alloy comprising at least gold or platinum or palladium or silver; the base and the cap plate are brazed to each other; the at least one cover plate has a thickness greater than or equal to 0.5 millimeters; the first alloy and the second alloy are selected to be hypoallergenic and have zero nickel content.

The invention also relates to a timepiece, in particular a wristwatch, comprising at least one external component as described above.

The invention also relates to a piece of jewelry, characterized in that said piece of jewelry is made of a bimetallic material, comprising a metal base made of a first material, said first material being titanium or a first titanium alloy, and at least one metal cover made of a second material, said second material comprising a second metal selected from gold, platinum, palladium or silver, and/or comprising a second alloy, said second alloy comprising at least gold or platinum or palladium or silver; the base and the cap plate are brazed to each other; the at least one cover plate has a thickness greater than or equal to 0.5 millimeters; the first alloy and the second alloy are selected to be hypoallergenic and have zero nickel content.

Drawings

Other features and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:

fig. 1 shows a schematic perspective view of an outer part according to the invention with a cover plate brazed to a profiled substrate;

fig. 2 shows a schematic perspective view of an outer part according to the invention with a cover plate brazed on a substrate and stamped together with the substrate after brazing;

fig. 3 shows a schematic perspective view of an outer part according to the invention, having a cover plate comprising a cut-out and brazed to a profiled substrate over only a portion of its lower surface facing said substrate;

fig. 4 shows a schematic perspective view of a bimetallic blank according to the invention, having a cover plate comprising a through hole and brazed on a substrate, and fig. 5 shows a cross-sectional view of an external component obtained by finishing the bimetallic blank of fig. 4, having an external profile formed by drawing and/or machining and a hole machined after brazing, in order to form, for example, a bezel;

fig. 6 shows a schematic perspective view of an outer part according to the invention with a cover plate comprising positioning holes and through holes, said cover plate being brazed on a substrate comprising positioning pins corresponding to the holes in said cover plate;

fig. 7 shows a schematic cross-sectional view of an outer part similar to that in fig. 2, with a deep-drawn section formed after brazing;

fig. 8 shows a schematic perspective view of an outer part according to the invention having a cover plate brazed to a forming substrate over only a portion of its lower surface facing the substrate;

figure 9 shows a schematic perspective view of an outer part according to the invention, similar to that of figure 8 and comprising H-shaped machined cut-outs formed in the assembly after brazing;

fig. 10 shows a schematic perspective view of an outer part according to the invention, having two cover plates brazed on the same substrate over only a part of the surface of the cover plate facing the lower surface of the forming substrate;

figure 11 shows a schematic perspective view of an outer part according to the invention, similar to that of figure 10, and in which four lateral wings are formed by drawing after brazing;

figure 12 shows a schematic cross-sectional view of an outer part according to the invention comprising two cover plates made of gold or platinum alloy and brazed on both sides of a titanium or titanium alloy substrate;

figure 13 shows a block diagram of a method of manufacturing a component according to the invention;

figures 14 to 18 show the machining of the jaw seat of the watch: FIG. 14 shows a perspective view of the preparation of a titanium substrate with cuts and through holes; fig. 15 shows a pre-folded substrate such that the beam formed by cutting in a first operation is transformed into a stirrup, fig. 16 shows a bimetallic blank formed after brazing a gold cover plate on a part of the surface of the substrate, fig. 17 shows a schematic end view of a segment obtained by sawing the blank, which segment is then shaped by deformation to form the outer part shown in fig. 18, in this case a claw seat;

figure 19 shows a simplified view of a watch with an external component according to the invention;

figure 20 shows a simplified view of a piece of jewelry made of bimetallic material according to the present invention.

Detailed Description

The invention proposes an alternative to the use of external parts of a timepiece made entirely of precious metals, in particular gold or platinum alloys, which are very heavy and expensive for the user.

In particular, for a watch component, which is the preferred application of the invention, although the invention is directly applicable to jewelry components, the outer component must exhibit excellent corrosion resistance and still have good mechanical properties.

The invention proposes to combine the advantages of high mechanical strength (durability) of a first component, hereinafter referred to as "substrate", made of a material chosen for its mechanical strength and corrosion resistance, with the advantages of the appearance and strong corrosion resistance of at least one second component, hereinafter referred to as "cover plate", in the same external part. The invention relates to solid parts, wherein the thickness E of each component is preferably greater than 0.5 mm.

In fact, as will be seen in the description that follows, the present invention encompasses a brazing operation. This operation is easier to control if the parts to be brazed to each other are thick and all have a comparable thickness. Naturally, the invention can also be implemented with components of smaller thickness, for example greater than 0.2 mm.

To this end, the invention relates to a method of manufacturing an outer part 100 of a timepiece or piece of jewelry 200.

According to the method:

-providing a metal substrate 10 made of a first material comprising a transition metal or titanium and/or a first alloy of said transition metal or titanium;

-providing at least one metallic cover plate 20 made of a second material comprising a second metal selected from gold, platinum, palladium or silver and/or a second alloy comprising at least gold or platinum or palladium or silver, said at least one cover plate 20 having a thickness E greater than or equal to 0.5 mm;

brazing said at least one cover plate 20 to said substrate 10 to form a bi-metal blank 30;

shaping said bimetal blank 30 by roll bonding or co-drawing or the like, and/or machining it to form the final form (shape, form) of the structural component 100 or jewelry 200 at the appropriate time.

In one particular method embodiment, the brazing operation is accomplished using a braze 40 selected to form a braze between the first material and the second material.

Advantageously, when the second material comprises gold, the braze 40 is composed of one material selected from the following materials or of a combination of several brazes of the following materials:

-Ag-Cu solder;

-Ag-Cu-X solder, component X being selected from Zn and Sn;

by Hilderbund&The CIE company (a company known as switzerland,commercial, zip code 1226) "CF 72 Ti" Ag-Cu-Ti;

by Hilderbund&The CIE company (a company known as switzerland,market, zip code 1226) "CFPDAG" Pd-Ag-Ga;

by Hilderbund&The CIE company (a company known as switzerland,market, zip code 1226) "CF PDXT 2" Pd300-Ag500-Cu 200;

by Hilderbund&The CIE company (a company known as switzerland,commercial, zip code 1226) of "CF 18KWH 2" Au750-Pd125-Ag20 without nickel.

Preferably, the first alloy and the second alloy will be chosen to be hypoallergenic and in particular with a nickel content of zero.

In one particular variant, the first material is chosen to comprise a transition metal selected from chromium, cobalt or molybdenum.

For the substrate 10, grade 2 titanium or grade 5 titanium or T35 titanium is advantageously selected as the first material of the substrate 10. Titanium grade 2 is particularly suitable for forming high quality brazes with gold alloys of 18K (K, carat). Titanium and its alloys form a family with similar mechanical properties to iron, which has a smaller mass than iron and has a very high corrosion resistance, especially against salt spray.

Preferably, an 18K gold alloy or a platinum alloy with at least 95% platinum is preferred as the second material.

When gold alloys are used, a gold alloy of 18K, 5N or 3N, is advantageously chosen as the second material.

In some variant embodiments, for example, as seen in fig. 2, the bimetal blank 30 is shaped by press-and/or draw-deformation.

In other variations, as shown in fig. 10 or 11, the bi-metal blank 30 is machined to partially remove the cover plate 20 so as to partially reveal at least one surface 16 of the substrate 10.

In an advantageous embodiment of the fixed part 100 of a watch or the like, the substrate 10 is advantageously chosen in the form of a shaped bar 11.

In some applications, as seen in fig. 3 or 4, it is optional to pre-form the cover plate 20 with at least one cut-out 21 and/or through hole 22.

For optimal relative positioning, the substrate 10 and the cover plate 20 are advantageously prepared with raised and/or hollow markings 15, 25, as seen in fig. 6, before being brazed to one another, in order to geometrically match them to one another before the brazing operation and to hold them relative to one another during the brazing operation.

In a variant, as seen in fig. 1, 2, 4, 6 or 10, the cover plate 20 is pressed against the substrate 10 over its entire contact surface with the substrate 10.

The example of fig. 4 and 6 shows, in a simplified manner, the machining of the bezel in the case of a bimetallic blank 30 prepared beforehand from a cover plate 20, which comprises the through-hole 22 and is brazed to the base 10. The blank 30 is then shaped by deformation and/or machining, with an outer contour formed by drawing and/or machining and a hole 12, said hole 12 being machined after brazing on the base 10 in the extension of the hole 22 or by reworking the hole 22 on the base 10 and the cover plate 20.

In other variants, the cover plate 20 is brazed to the substrate 10 on only a part of its surface 26 facing the substrate 10 and/or on only a part of its surface 16 facing the cover plate 20.

Naturally, it should be understood that the concept "bimetal" is not limiting, since the substrate 10 itself can be made according to the invention and comprises a pair of brazing layers: the invention also applies to a sandwich-type outer member 100 comprising two cover plates 20 made of gold or platinum alloy brazed on both sides of a base 10 made of titanium or titanium alloy. Such a configuration may be required due to appearance limitations. The titanium core layer ensures rigidity and precise positioning with respect to the other parts of the timepiece. As can be seen in fig. 12, if the cover plates 20 are flat and are soldered or welded in gold-gold manner at the joint 35, the cover plates 20 can be connected to one another at the connection surface 34 or at the connection plane. The invention thus extends to the manufacture of a large number of parts made by brazing pairs of opposed surfaces, one of which is made of titanium or a titanium alloy and the other of which is made of gold or a gold alloy or a titanium alloy.

The invention also relates to an external part 100 of a timepiece, made of a bimetallic material and comprising a metal base 10 made of a first material comprising titanium or a transition metal other than nickel, and/or comprising titanium or a first alloy of said transition metal, and at least one metal cover plate 20 made of a second material. The second material comprises a second metal selected from gold, platinum, palladium or silver, and/or comprises a second alloy comprising at least gold or platinum or palladium or silver. The substrate 10 and the cover plate 20 are assembled to each other by a brazed connection, and the at least one cover plate 20 has a thickness E greater than or equal to 0.5 mm.

More specifically, the bimetal outer part 100 of a timepiece comprises a metal base 10 made of a first material comprising titanium and/or a first titanium alloy, and at least one metal cover plate 20 made of a second material comprising a second metal selected from gold and platinum and/or a second alloy comprising at least gold or platinum, and the base 10 and the cover plate 20 are brazed to each other, and the cover plate 20 has a thickness E greater than or equal to 0.5 mm.

The invention also relates to a timepiece, in particular a wristwatch 1000, comprising at least one external component 100 as described above.

The invention also relates to a piece of jewelry 200 made of a bimetallic material and comprising a metal base 10 made of a first material comprising titanium or a transition metal other than nickel, and/or comprising a first alloy of titanium or of said transition metal, and at least one metal cover 20 made of a second material. The second material comprises a second metal selected from gold, platinum, palladium or silver, and/or comprises a second alloy comprising at least gold or platinum or palladium or silver. The substrate 10 and the cover plate 20 are assembled to each other by a brazed connection, and the at least one cover plate 20 has a thickness E greater than or equal to 0.5 mm.

Fig. 14 to 18 show a non-limiting example of making a jaw receptacle 100 for a watch 1000.

As seen in fig. 14, a titanium substrate 10 is cut out of a thin plate or plate, having cuts 13 and through holes 12 so as to form a ladder structure with lateral bearing surfaces 14 connected by cross beams 18;

as seen in fig. 15, these crossbeams 18 are bent to form stirrups 19, the base then being ready to receive the cover plate 20;

brazing the two gold caps 20 on the lateral bearing surfaces 14 of the substrate 10, as seen in fig. 16, thus obtaining a bimetallic blank 30;

fig. 17 shows a section 35 obtained by sawing or cutting along the cutting line 32 of the blank 30;

the segment 35 is then shaped by deformation to form the external part 100 shown in figure 18, in this case a watchcase jaw.

The invention is particularly suitable for making external parts such as watch bezel (bezel, glass-lined round frame), claw holder, watch case, links of watch band, buckle (clasp), but this list is non-limiting. The invention provides the user with a high quality part of light alloy or metal in combination with the use of precious metals in large thicknesses brazed on to ensure resistance to deformation and mechanical stresses and still provide portability which is more pleasant for the wearer.

Claims (12)

1. Method for manufacturing an external part (100) of a timepiece or piece of jewelry (200), characterized in that:

-providing a metal substrate (10) made of a first material, said first material being titanium and/or a first titanium alloy;

-providing at least one metallic cover plate (20) made of a second material comprising a second metal selected from gold, platinum, palladium or silver and/or a second alloy comprising at least gold or platinum or palladium or silver, said at least one cover plate (20) having a thickness (E) greater than or equal to 0.5 mm;

-brazing said at least one cover plate (20) on said substrate (10) so as to form a bimetallic blank (30);

-then shaping said bimetal blank (30) so as to produce a final form of said outer part (100) or said piece of jewelry (200); wherein the content of the first and second substances,

-said external part (100) or said piece of jewelry (200) is a watchcase jaw;

-said substrate (10) is cut out of a sheet or plate, having cuts (13) and through holes (12) so as to form a ladder-like structure with lateral bearing surfaces (14) connected by cross beams (18);

-bending the crossbar (18) to form a stirrup (19);

-brazing the two cover plates (20) on the lateral bearing surfaces (14) of the base (10) to form a bimetallic blank (30);

-cutting said bi-metal blank (30) into segments (35);

-shaping said segment (35) by deformation so as to form said watchcase jaw.

2. Method according to claim 1, characterized in that a titanium alloy is chosen as the first material of the substrate (10), which titanium alloy is grade 2 titanium or grade 5 titanium or T35 titanium.

3. A method according to claim 1, characterized in that the brazing operation is carried out with a brazing filler metal (40) selected to form a braze between the first material and the second material.

4. The method of claim 1, wherein the first titanium alloy and the second alloy are selected to be hypoallergenic and have zero nickel content.

5. The method according to claim 1, characterized in that an 18K gold alloy or a platinum alloy with at least 95% platinum is selected as the second material.

6. The method according to claim 5, characterized in that a 5N or 3N 18K gold alloy is selected as the second material.

7. The method according to claim 1, wherein the bimetal blank (30) is formed by press-and/or draw-deformation.

8. A method according to claim 1, wherein said bimetal blank (30) is machined to partially remove said cover plate (20).

9. A method according to claim 1, characterized in that the substrate (10) is selected to have the form of a profiled rod (11).

10. Method according to claim 1, characterized in that the substrate (10) and the cover plate (20) are prepared with raised and/or hollow markings (15; 25) before being brazed to each other in order to geometrically match the substrate and the cover plate to each other before the brazing operation and to hold the substrate and the cover plate relative to each other during the brazing operation.

11. Method according to claim 1, characterized in that the cover plate (20) is brazed to the substrate (10) over its entire common contact surface with the substrate.

12. Method according to claim 1, characterized in that the cover plate (20) is brazed to the substrate (10) on only a part of the surface (26) of the cover plate (20) facing the substrate (10) and/or on only a part of the surface (16) of the substrate (10) facing the cover plate (20).