EP0257453B1 - Watch case - Google Patents

Abstract

The middle part (1) and the dial (4) of the watch case are manufactured in a single piece, which is made from a natural mineral. Decorative assemblies (10) are mounted in blind housings (8) in the dial (4). These assemblies each comprise an element (11) which advantageously has a diamond cut, with collet, crown and table, and which is crimped in a cap (16), itself embedded in the housing (8). <IMAGE>

Description

The present invention relates to watch cases of the type comprising a middle part made in one piece with a dial, this carry-dial assembly being made of a natural mineral material.

Such a box is described and represented in the review SCHMUCK & UHREN vol 39, no 6, of June 1986, page 6, under the title "Die Rockwatch".

This type of box has a particularly attractive aesthetic appearance. However, because of the fragility of natural mineral materials, it is out of the question to fix marks or indexes by riveting, hunting or welding. Furthermore, the printing of signs has so far not given satisfactory results.

An object of the present invention is to produce a box as defined above, with which a decorative assembly is associated.

The above object is achieved thanks to the fact that, in the box as defined above, said dial, on the side of its visible face intended to display the hours and minutes, comprises a blind housing in which is freely engaged a cap in which is crimped and held firmly in place an element having the shape and appearance of a cut stone, this cap being glued under the bottom against the corresponding bottom of this housing.

It has in fact been found that among the elements capable of being used as decoration, transparent and cut materials such as diamond, sapphire, but also glass, even plastic, give an aesthetically satisfactory result. These elements, with very geometric shapes, contrast with the random shapes presented by natural mineral materials.

However, the fixing of an element having the shape of a cut stone on a dial made of natural mineral material, poses some problems. It is out of the question to drive the element into a hole in the dial, because of its fragility. It is also not possible to paste the element directly on the dial, the shimmer of this element being destroyed. It is therefore necessary to mount the stone on a kitten.

It is also necessary that the mounting system of the kitten on the dial does not cause any excess thickness.

It is by using a cap as a kitten, by drowning it in a blind housing and by sticking it against the bottom of this housing that all the problems posed have been able to be resolved.

Certainly, watches already known are provided with a decorative assembly with a cut stone, either in the middle or in the dial.

Document JP-A-58 66 087 describes a process allowing the affixing of a decorative element made of inorganic material, such as ceramic or glass, on a watch case made of a "superplastic" alloy. This process consists in depositing a thin metallic film on the decorative element, placing between two matrices the decorative element superimposed on the box, heating the assembly to make the metallic film and the box plastic, then applying pressure on the two dies to force the decorative element into the material of the box by inclusion.

However, this method cannot be applied to a watch case made of natural material, such as granite, since such a material has no property of superplasticity or even of plasticity or elasticity.

Document JP-A-60 80 784 describes a method of fixing an uncut decorative element to a middle part, this method also consisting in depositing by evaporation a layer of metal on the decorative element, then in welding this layer of metal by a laser beam which is oriented in the element itself and which carries the layer of molten metal.

This process, which does not concern the affixing of a cut stone on a dial made of mineral material, cannot in any case apply to a cut stone since cutting makes the orientation of the laser beam impossible.

Document CH-A-260 123 relates to a dial provided with cut stones fixed by means of a ring driven from below the dial. Hunting makes it impossible to apply this device to a dial made of natural mineral material.

Furthermore, document CH-A-609 517G describes a watch with stones mounted on envelopes, and mobile in an annular housing, while document DE-A-3 307 817 describes a method for setting stones in a dial made of metal.

Finally, the document FR-A-2 437 024 relates to an extra-flat watch comprising a bezel in which rectilinear slides are formed constituting housings for receiving an ice cream, the bezel made of material, firstly, with middle of said watch and, on the other hand, with a concave dial made of metal, such as for example gold.

None of these documents describes or suggests a process or a structure which answers the problem posed here.

The cap which is engaged according to the invention claimed in the blind housing of the dial holds the element it contains perfectly in place and it does not need to be forcibly engaged in the side wall of its housing, at the risk to blow up the dial.

It therefore does not create any internal tension in the latter and the area of its bottom is largely sufficient for perfect adhesion.

In addition, in this construction, the border formed by the cap between the decorative element and the material of the dial further emphasizes the desired contrast.

The fragility of natural mineral matter poses, as has been said above, problems which are difficult to solve.

Another object of the present invention is to minimize the strength of the box.

This object is achieved thanks to the particular structure presented by the box of claim 2. In this box, the visible face of the dial is concave and the housing, intended to receive the element, is located at the periphery of this dial.

The concavity of the dial solidifies the box-dial assembly and facilitates machining. In this way, the edge of the dial rises to the level of the notch of ice. In other words, the edge of the dial serves as a flange. This therefore results in a reduced space for the passage of the minute hand. It is therefore essential that the element takes a minimum of space in height. This is why the cap is embedded in the housing. The hole, although relatively deep, does not affect the strength of the assembly. This is probably due to the fact that it is in the immediate vicinity of the strongest part: the middle part.

The embodiments defined by claim 3 ensure a simple and satisfactory manufacture of the cap and crimping of the element which it contains. In addition, this folded edge of the cap creates a welcome contrast to the visible face of the dial, especially if it is polished and gold or silver.

In those defined by claim 4, the depth of the housing of the cap is much less than the thickness of the dial; it is approximately equal to the height of the cylinder head of said element, which is relatively small.

Those defined by claims 5 to 7 aim to give said element a certain luster, in particular if this element is not made up only of a piece of glass, crystal, transparent plastic or rhinestones.

Finally, in those defined by claim 8, the decorative element which acts as a time sign, facilitates the reading of the time, without altering the aesthetics of the watch.

• la figure 1 est une coupe radiale par "3 h." de la carrurecadran de cette boîte;
• la figure 2 est une vue en élévation avec une partie en coupe d'une pièce de la figure 1 à plus grande échelle, et
• la figure 3 est une vue en plan de la pièce représentée à la figure 2.

An embodiment of the watch case according to the invention and some variants are described below by way of example and with reference to the drawing, in which:

• Figure 1 is a radial section through "3 h." the square face of this box;
• FIG. 2 is an elevation view with a sectional section of a part of FIG. 1 on a larger scale, and
• FIG. 3 is a plan view of the part shown in FIG. 2.

The middle 1, shown in Figure 1, is made of a natural mineral material, such as granite. It has a bore 2 for the passage of a time-setting rod (not shown) of the watch, and a notch of ice 3, intended to receive a flat sapphire crystal or tempered mineral glass. This middle part 1 came from one-piece production with the dial 4 of the watch.

This middle part / dial defines a housing 5 intended to receive the movement of the watch (not shown), as well as, in its periphery, a metal ring (not shown) which, glued to the middle part, increases its solidity.

The dial 4 has a central opening 6 for the passage of the axes (not shown) of the hands (not shown) of the watch. The visible face 7 of the dial 4 is concave, which gives the stability of the middle / dial assembly and facilitates machining. The edge of the face 7 joins the bottom of the notch of ice 3 and thus acts as a flange. A blind circular cylindrical housing 8 with a flat bottom 9 is finally formed in the face 7, at the periphery of the dial 4. A decorative assembly 10, representing the time sign "3 h." is mounted in the housing 8.

The assembly 10 is shown in detail in Figures 2 and 3. It consists essentially of an element 11 of transparent material having the size of the diamonds, or any other size offering an attractive aesthetic appearance. This element 11 includes thus a cylinder head 12, in which several facets 13 are cut, and a crown 14 which is also faceted and surmounted by a table 15.

For the economy of the box, the element 11 will preferably consist of a piece of glass, crystal, transparent plastic or rhinestones. Nothing however excludes the use of a brilliant.

This element 11 is housed in a cap 16, the bottom 17 is flat and the side wall 18 circular cylindrical. The upper edge 19 of the wall 18 is folded down at 19a over the sheet 20 of the element 11. It thus constitutes a crimping of the latter in the cap 16, which therefore holds it firmly in place.

The cap 16 is preferably made of brass. The visible face of the edge 19a is polished and, preferably, gold or silver to create a contrast with the granite of the face 7 of the dial 4. This cap could also be made of gold or silver.

The assembly 10 is fixed to the dial 4 by bonding the bottom 17 of the cap 16 to the bottom 9 of the housing 8. To avoid internal tensions in the dial 4, the diameter of the cap 16 will be slightly less than that of the housing 8.

As seen in Figure 1, the cap 16 is fully embedded in the housing 8. It is therefore at most the crown 14 of the element 11 which projects from the face 7 of the dial 4. There therefore remains a space amply sufficient between the table 15 of the element 11 and the crystal (not shown) of the watch for the passage of the hands.

A sign similar to that of FIGS. 2 and 3 is fixed to the dial 4 respectively at "12 h.", "6 h." and "9 a.m.". Analogous signs could naturally also be fitted for each of the twelve hours of the dial. Alternatively, only one of these signs could also be expected at "12 noon." or this one is distinguished from the others for example by its dimensions.

When the element 11 is made of a base material, it is possible to obtain a luster which somewhat resembles that of the diamond by polishing the internal faces 21 of the cap 16 to the point of reflecting the light passing through the element 11. In in this case, the inside of the cap 16 is advantageously conical in shape, the opening of the cone being chosen so that its surface is substantially parallel to the facets 13. This surface can even be coated with a colored material.

In order to obtain a similar effect, the facets 13 of the cylinder head 12 could also be provided with a reflective layer, colored or not.

Claims (8)

1. watch case of the type comprising a caseband (1) as well as a dial (4) integrally manufactured with the caseband, such assembly caseband-dial (1, 4) being formed from a natural mineral material such as granite for example, characterized in that said dial (4) from the side of its visible face (7) intended for visualizing hours and minutes, includes a blind bed (8) in which a cup (16) is freely engaged, an element (11) exhibiting the form and aspect of a cut stone being set and firmly maintained in said cup, such cup (16) being glued by its base (17) against the corresponding bottom (9) of said bed.
2. Case as in claim 1 characterized in that the visible face of the dial (4) is concave, in that said bed (8) is located at the periphery of said dial (4) and in that said cup (16) is buried in said bed (8).
3. Case as in claim 1 or 2 characterized in that said element (11) exhibits a diamond cut and that said cup (16) has a side wall (18) in circular cylindrical form the upper edge (19) of which is folded down on the rift (20) of said element (11) to constitute the setting of this latter.
4. Case as in claim 3 characterized in that at the most only the crown (14) of said element (11) projects from the visible face (7) of the dial (4).
5. Case as in claim 4 characterized in that the internal faces (21) of said cup (16) are reflecting.
6. Case as in claim 5 characterized in that the reflecting faces (21) of said cup (16) are coated with a coloured material.
7. Case as in claim 4 characterized in that the facettes (13) of the head (12) of said element (11) are furnished with a coloured reflecting material.
8. Case as in one of claims 1 to 7 characterized in that the assembly (10) formed from said element (11) and from the cup (16) acts as a time indicating sign.

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