EP0098240B1 - Watch case - Google Patents

Abstract

A crystal (1) of a wristwatch case contains a sapphire base plate (2) which, in front view, entirely covers the body (3) of the case. That plate (2) is in turn entirely covered by a second sapphire plate (4) which is glued (5) to plate (2) very rigidly. The crystal (1) is fastened to the body (3) by screws engaged from the back side of the body (3) in sockets (7), a head (9) of which is captured between the two plates (2, 4) of the crystal (1). The position of the sockets (7) is exactly determined by a conical seat (10) of housings hollowed out in plate (2), at the bottom of which rests the conical head (9) of the sockets (7). Flats (14) are formed on the heads (9), so that the glue forms packings (15) preventing the sockets (7) from turning while screwing the crystal (1). The upper face (6) of the square (3) and the heads (9) of the sockets (7) are masked by a metal coating (12) deposited by vacuum spraying on the other side of plate (4). The crystal (1) is, furthermore, decorated with semicylindrical colored sapphire baguettes (16) glued in corresponding grooves (19) of plate (4).

Description

Wrist watch cases conforming to the preamble of claim 1 have been proposed, for example in patent application EP-A-0 064 951 (enjoying the priority of 01. 05.81). In these boxes, the sockets used to fix the glass to the middle by screwing are secured to the glass by means of a frame glued under the glass.

The present invention aims, among other things, to simplify this construction without sacrificing the possibilities of decorating the box, on the contrary, and this even by increasing the solidity of the glass.

The features defined by the characteristic of claim 1 make it possible to obtain this result. Because the head of the sockets is trapped in the glass itself, it is no longer necessary to fix a frame under it. In addition, due to the two sapphire plates glued to each other, the glass is more solid than if it were made in one piece. Furthermore, we find between the two sapphire plates glued to each other practically the same possibilities of decorating the box as those offered by a frame glued under the glass.

The cones formed in the base plate of the glass and the conical heads of the glass fixing sleeves, provided in the separate embodiments defined by claim 2, allow, by placing these heads in their seats, to center the say sockets, that is to say fix them in the exact place you want. The pressure they exert on the glass base plate is not dangerous. Even if, by chance, it came to produce a rupture of this base plate, a piece of it could not come off; it would remain stuck, in fact, to the sapphire plate stuck on the base plate.

The embodiments defined by claim 3 are as simple as advantageous. The two plates that make up the glass have the same shape and the latter is doubled throughout its extent. In addition, since these two plates are bonded directly to each other throughout the transparent part of the glass, it is not necessary to pay special attention to the adhesion of the metallization layer formed on the back of the plate. glued from the glass. Thus trapped entirely between two sapphire plates, this layer is completely inaccessible; it is perfectly sheltered from any contact with foreign bodies. Unless the glass is destroyed, nothing can alter it.

Decorative elements may also be provided in the external face of the glass, provided that their hardness protects them from depredation, as defined in claim 4.

The special embodiments defined by claim 5 have several advantages. Although a sapphire plate with simply ground face is not transparent, but only translucent, the glue has the effect of filling the fine grinding streaks, so that the set of two sapphire plates glued one on the the other becomes perfectly transparent. This avoids the costly polishing operations of one of the faces of the two sapphire plates. In addition, such a glass is anti-reflective. It is therefore no longer necessary to subject the face of the dial to special treatment intended to make it matt. Finally, this glass makes it possible to produce, as desired, matt or shiny metallic layers, on the reverse of the bonded plate, depending on whether the simply ground face in question is the underside of the bonded sapphire plate or the upper face of the plate. basic glass.

An independent frame, for example of precious or semiprecious stone, can also be interposed between the two sapphire plates glued one on the other, provided that its thickness does not preferably exceed two tenths of a millimeter, as well as stems from claim 6.

In the case of quadrangular glasses (rectangular or square), it is not essential to glue a single plate on the base plate of the glass. As defined in claim 7, it is possible to separately make a plate extending at least in the transparent area of the glass and opaque plates to mask the glass fixing sleeves while constituting the decoration of the visible face of the box, these different plates are perfectly juxtaposed, so as to cover the entire face of the base plate of the glass, and glued to the latter.

As the assembly forming the glass is relatively thick (which does not increase the apparent thickness of the watch, due to the transparency of the glass), it is possible, as defined in claim 8, to dig therefrom alveoli deep enough to accommodate the cylinder head of cut diamonds and into which it can be glued avoiding any risk of losing these stones.

• la Fig. 1 est une coupe partielle de la première forme d'exécution;
• la Fig. 2 en est une vue en plan à plus petite échelle, une partie étant arrachée;
• la Fig. 3 en représente le verre en perspective, une partie étant coupée et une autre illustrant en perspective éclatée le mode de fabrication de ce verre;
• la Fig. 4 est une vue semblable à celle de la Fig. 3, représentant la deuxième forme d'exécution;
• la Fig. 5 est une coupe partielle d'un détail de la troisième forme d'exécution, et
• la Fig. 6 est une vue en perspective de la quatrième forme d'exécution.

Four embodiments of the wristwatch case according to the invention are shown schematically and simply by way of example in the drawing in which:

• Fig. 1 is a partial section of the first embodiment;
• Fig. 2 is a plan view on a smaller scale, a part being torn away;
• Fig. 3 shows the glass in perspective, one part being cut and another illustrating in exploded perspective the method of manufacturing this glass;
• Fig. 4 is a view similar to that of FIG. 3, representing the second embodiment;
• Fig. 5 is a partial section of a detail of the third embodiment, and
• Fig. 6 is a perspective view of the fourth embodiment.

The box according to the first embodiment (Fig. 1 to 3) has the general shape of a rectangle. Its sapphire glass 1 is flat. It includes a base plate 2 which, seen from the front, hides the middle part 3 of the case by completely covering it. A second plate 4 is permanently fixed to the plate 2 by a layer of adhesive 5.

The glass 1 rests on the flat upper face 6 of the middle part 3, left in the state in which the strip used for machining the middle parts 3 leaves the rolling. It is fixed to this face of the middle part by four screws (not shown) engaged from the bottom side of the middle part in the threads of four sockets 7 located in the vicinity of the angles of the box, one of these being shown in Fig. 1. The said screws and the sockets 7 pass through axial holes 8 which pass right through the middle. Incidentally, these screws can be used at the same time to fix the bottom of the case to the middle part 3, as described in patent applications EP-A-0 064 950 and EP-A-0 064 951 (each enjoying the priority from 01.05.81). In order to hold the glass 1 in a precise position on the middle part 3, the diameters of the sockets 7 and of the holes 8 are adjusted to one another with gentle friction. In this way, the sockets 7 are exactly positioned on the middle part 3. They are also positioned relative to the glass 1, thanks to a conical seat 9, which is formed at the bottom of the sockets 7 and which rests on a seat 10 of same taper of the base plate 2.

If it is not possible to drill in a sapphire plate series of cylindrical holes of strictly constant diameter, due to the very rapid wear of the drilling tool, we can, however, position the axis of conical seats such as 10 with very high precision. So that the axis of the sockets 7 coincides with that of the corresponding seats 10, it is naturally necessary that the seats 9 are well pressed against the bottom of their seats 10. For this purpose, it is possible to engage a cylindrical sleeve on the part of each socket 7 extending under the plate 1, then engage in each of these sockets a screw whose head is supported on the corresponding sleeve. In this way, said sleeve is pressed against the underside of the plate 2. This makes it take a position perfectly perpendicular to this plate 2, which it naturally communicates with the socket 7 on which it is engaged. In addition, said screw pulls the seat 9 at the bottom of the seat 10 and holds it firmly in this position, in which its axis coincides with that of this seat.

So that the glass plate 4 can then rest properly on the plate 2, it is important that the seats 9 of the sockets 7 do not protrude above the plate 2. To satisfy this condition, the seats 10 are hollowed out to a depth slightly higher than the height of these seats 9, as shown in FIG. 1. The latter also shows fine streaks 11 on the back of the plate 4. This face of the plate 4 has, in fact, not been polished, but simply ground, so that this plate has, in the dry state , the appearance of a frosted glass. In this state, a thin metallization layer 12 is deposited by vacuum spraying on the reverse of the periphery of the plate 4. This metallization can be compact as shown in FIG. 2. It could also include a first deposit, for example of gold, which could be cut chemically so as to create a decorative pattern (fillets, arabesques or other), then covered with a second protective deposit, constituting at the same time a background. in the cutouts of the first deposit.

As the metallization 12 is deposited on a surface of the plate 4 which has only been subjected to a simple grinding, it appears mat through this plate 4.

When the sockets 7 and the aforementioned sleeves have been fixed in the manner described in plate 2, these sleeves can be used to hold this plate in a very precise position, by engaging them in corresponding holes of an appropriate fitting. At this stage, the upper face of the plate 2 and the lower face of the plate 4 are coated with a layer of adhesive such as, for example, one of those sold under the brand "LOCTITE", references 357 or 358, which polymerize in ten seconds under the action of ultraviolet rays, or, references 317 or 318 which, added to an activator, polymerize in one hour at 80 ° C. As these adhesives are very fluid and very wetting, they fill the ridges 11 by making the plate 4 perfectly transparent. It is, moreover, easy to apply these adhesives while avoiding any air bubble, which would have the effect of disturbing the aesthetic effect of the glass 1.

The plate 4 is then placed on the plate 2 and kept in the desired position on this plate, then the assembly is subjected, depending on the nature of the adhesive, to ultraviolet radiation or to heat. This operation causes the adhesive to polymerize to the point of causing adhesion of several tens of N / mm2 (kgp / mm ² ). However, only the glue caught between the plates 2 and 4, excluding the "overflow" seeping around these plates, undergoes the polymerization described. The beads of glue around these plates remain soft and can be easily removed.

We notice in Fig. 1 that the metallization 12 extends from the edge of the plate 4 inwards, up to a little beyond the opening 13 of the middle part 3, in which the dial (not shown) of the watch is intended to appear. As the ridges 11 have been filled with glue, the area of the glass included inside the metallization layer 12 is perfectly transparent. In addition, this glass area has an anti-reflective effect. This has the advantage that the dial no longer needs to be subjected to laborious operations intended to make the surface matt. Fig. 1 also shows that the adhesive layer 5 not only extends throughout the space between the adjacent planar faces of the plates 2 and 4, but that it also fills the spaces of the conical recesses 10 of the plate 2 that the seats 9 of the sockets 7 leave free.

To certainly prevent the sockets 7 from rotating relative to the glass 1, when the latter is screwed onto the middle part 3, at least one flat part 14, but preferably two (Fig. 2 and 3) are formed on the seat 9 of each socket 7, so that the adhesive forms locking pins 15 between these flats and the seats 10.

Figs. 1 and 2 show that the plate 4 carries, along each of its sides, above the metallized layer 12, three semi-cylindrical rods 16, which are glued in grooves of the same shape of the plate 4. These rods are made of corundum or colored sapphire, that is to say in the same basic material as the plates 2 and 4. A reflective metallization layer is deposited on their cylindrical face, so that the incident light is reflected in a narrow median zone of these rods, where it forms a line of intense luminosity 17 (Fig. 2).

Finally, the seal between the glass 1 and the middle part 3 is ensured by a gasket 18, housed in a groove made in the face 6 of the middle part 3.

Fig. 3, in which only one rod 16 per side of the glass has been shown for simplicity, shows how the glass 1 can be obtained. In the right part of this figure, we see that at the start, the sapphire plates 2 and 4 are perfectly rectangular. Their angles are sharp and their edges perpendicular to the faces. Semi-cylindrical grooves 19, equal in number to that of the rods 16 which one wishes to incorporate into the glass, are hollowed out from one edge to the other of the plate 4. At the start, these colored sapphire rods are cylindrical, as we see it in 16a in Fig. 3. Their manufacture is easy and inexpensive. The cylindrical face of the rods 16a is polished and then coated with a reflective metallization layer. These rods 16a are then glued into the grooves 19 of the plate 4, then their projecting part of this plate is removed by grinding, so as to bring the ground face of these rods flush with the upper face of the plate 4, which can then be polished at the same time as the uncovered face of the rods 16. It can happen that these operations result in a reduction in the thickness of this plate, therefore in the extent of the grooves 19 and of the rods 16, to the point that their section will only have the shape of a circular segment. If this reduction does not influence the aesthetic effect of the rods 16 appreciably, it should however not be pushed to the point of compromising the adhesion of these rods to the bottom of the grooves 19. After having subjected the back of the plate 4 to the metallization described, this plate can be glued to the plate 2.

It is however possible to dig the grooves 19, to stick the rods 16a there, to grind them then to polish the upper face of the plate 4 after it has been glued to the plate 2.

The glass thus obtained is then bevelled, as seen in 20 in FIG. 2, then bevels 21 are formed all around the upper edge of the glass, the sides 22 of which can be polished at this time. The length of the rods 16a is chosen so that their ends are bevelled at the same time as the plate 4.

We also notice in Fig. 3 that the rods 16a, extending along the short sides of the glass, were glued in place before digging the grooves 19 along the long sides of the plate 4. Thus, the rods 16a, glued last, s '' fit without continuity in the hollowed out parts of the sticks already glued along the short sides of the plate 4.

Although the seats 9 of the sockets 7 are located inside the glass 1 itself, the ornaments 12, 16 do not only camouflage these sockets; they give the visible side of the box a highly original appearance.

Instead of leaving the streaks 11 remaining on the underside of the plate 4, one could also leave them on the upper face of the base plate 2. The adhesive would behave in the same way with them. The central part of the glass would also be perfectly transparent and we would obtain the same anti-reflection effect. As the metallization layer 12 would be deposited on a polished surface, it would however appear shiny.

Since the two sapphire plates 2,4 are very firmly joined to each other in the transparent area of the glass 1, it is not necessary for the metallization layer 12 to adhere particularly well to the plate 4. Since layer 12 is trapped between these two plates, which protect it, one can very well deposit in this place for example a layer of silver or aluminum, whose relatively reduced adhesion has prohibited its use in all case this layer is exposed, although its appearance is as attractive as it is original.

If, following a chemical cutting of a first deposit on the back of the plate 4, the metallization 12 gives the glass 1 and consequently the box an already sufficiently decorated appearance, we will of course renounce any other addition of ornament on the plate 4.

The second embodiment differs from the first only by its glass 23, the only one shown in FIG. 4. This glass comprises a base plate 2, identical to that of the first embodiment. The sockets 7 are temporarily attached to it in the same way. In this case, this base plate is not covered by a single one, but by three sapphire plates 24, 25, the plate 24 covering the middle part of the plate 2 and the plates 25 extending along the long sides of the plate 2. The plate 24 and the two plates 25, which have the same thickness, are perfectly juxtaposed and completely cover the plate 2. The two end zones of the plate 24, intended to extend above the middle of the box, are clouded so decorative, as in the first embodiment. As for the plates 25, they are entirely opaque and mask the bases 9 of the sockets 7. They can be made of colored sapphire or have a metallization layer on their reverse. In addition, "V" grooves 26 are hollowed out through the plates 25. As this hollowing produces grooves with flared edges, they are formed in thicker plates, then the excess thickness is removed by grinding, after bonding of the plates 25 on the base plate 2, in order to obtain grooves 26 with clean edges, the sides of which constitute reflective facets, producing a decorative effect.

In place of or in addition to the plates 25, similar plates could also be glued along the short sides of the plate 24, the latter being made shorter and possibly wider, so that the set of plates glued on the base plate 2, always completely cover the latter without overflow, of course concealing the seats 9 of the sockets 7.

In the third embodiment (Fig. 5), the metallization layer, provided in the first embodiment to hide the upper face of the case middle and the seats of the glass fixing sleeves, is replaced by a metal or precious or semi-precious stone frame 12a, in one or more pieces, which is glued under the plate 4. In order for the glue to set properly in the transparent area of the glass, it is however important that this frame is sufficiently slim. Preferably, its thickness will not exceed two tenths of a millimeter. This way of clouding the periphery of the glass is obviously also applicable in the first two embodiments. It goes without saying that such a frame is protected in the same way as the metallization described. Even made of very soft metal, it therefore gives the box an unalterable appearance.

Instead of the rods 16 of the first embodiment, it is one or more cut diamonds which, in this third embodiment, are mounted in the glass. For each diamond, a conical cell 32 is hollowed out for this purpose through the plate 4, into a part of the base plate 2. As these cells 32 do not pass through the glass 1, they do not compromise their sealing . In addition, the resulting weakening of the glass is completely negligible. The cylinder head 33 of a cut diamond 34 is then glued into each of the cells 32. The adhesion of the glue 35 eliminates any risk of losing the brilliants 34. Furthermore, a brilliant mounted in this way has more effect than s 'it was set in a metal frame, because it receives light from all sides through the sapphire glass and the layer of glue 35, which is perfectly transparent.

The fourth embodiment (Fig. 6) differs from the previous ones first of all by the shape of the box, which is square. The glass 27 of this embodiment also comprises a base plate 28, which is square and which entirely covers the upper face of the middle part 29. A central square plate 30, entirely transparent, and four plates 31, opaque or opacified of the same way as in the previous embodiments and of generally triangular shape, are bonded to the base plate 28, so as to completely cover it, without overflow, by masking the upper face of the middle part 29 and the bases of the sockets for fixing (not shown) the glass 27 to the middle part 29.

In addition, four diamonds 34 are mounted in the glass 27 near the corners of the plate 30, as described in the third embodiment. Instead of showing time signs, as is the case in this embodiment, the brilliants could obviously be mounted in other places of the watch glass, for example at the corners of the case.

Claims (8)

1. Case for a wristwatch the sapphire crystal 23, 27) of which is flat seen from its face and conceal the caseband (3) of the case by covering it entirely and is fastened thereto by screws passing from the bottom side thereof into sockets (7) united with the crystal by a bedding (9) of greater diameter than they exhibit at their bottom characterized in that the bedding (9) of each socker (7) is rigidly embedded in the interior of the crystal (1, 23, 27) between two plates of sapphire (2,4; 2, 25; 28, 31) glued to one another and in that such beddings (9) are concealed by ornaments (12, 12a) incorporated in the crystal (1, 23, 27).

2. Case according to claim 1 characterized in that its crystal (1, 23, 27) comprises a base plate (2, 28) which covers its entire surface, in that openings are pierced through said plate (2, 28) for each of said sockets (7), the portion (10) opening into the surface of such plate (2, 28) intended for gluing being conical and in that the beddings (9) for said sockets (7) exhibit the same taper and a height equal at most to that of the conical portion of said openings in a manner such that said beddings are entirely embedded in the base layer (2, 28) of the crystal (1, 13, 27).

3. Case according to claim 2 characterized in that a single plate of sapphire (4) is glued onto the base plate (2) of the crystal (1) which is entirely covered without any edge spillover and in that said ornaments comprise a layer of metallisation (12) formed by vapourisation under vacuum applied to the reverse side of the peripheral zone of said glued plate.

4. Case according to claim 3 characterized in that said ornaments comprise, in addition, strips (16) of coloured sapphire having a cross-section in the form of a circular segment but comprising at most a half circle and are glued into grooves (19) having a corresponding form arranged on the external face of the plate of sapphire (4) of the crystal (1) glued onto the base plate (2) said strips (16) being flush with said external face, there being a layer of metallisation formed by vaporization under vacuum in said grooves (19).

5. Case according to claim 3 or claim 4 characterized in that one of the surfaces of said plates of sapphire (2,4) of the crystal intended to be glued together is ground to exhibit fine striations.

6. Case according to claim 2 characterized in that a single plate (4) of sapphire is glued onto the base plate (1) of the crystal so as to cover it entirely and in that said ornaments comprise a thin frame (12a) formed of one or several juxtaposed decorative elements, said frame being interposed between said sapphire plates of the crystal and fixed thereto by gluing.

7. Case according to claim 2 the crystal of which has a rectangular form characterized in that a set of juxtaposed plates (24, 25; 30, 31) of the same thickness is glued onto the base plate(2, 28) so as to cover it entirely with no edge spillover, said set comprising a central sapphire plate (24, 30) which extends at least over the entire transparent area of the crystal and layers of sapphire (25, 31) which are obscured by ornaments and which extend along at least two sides of the crystal or into the angles thereof.

8. Case according to one of the preceding claims characterized in that said ornaments comprise at least one brilliant (34) which is glued into a conical cell (32) bored through a plate of glued sapphire (4, 30) and extend ing into a portion of the base layer (2, 28).

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