CH685903B5 - Watch case with glass glue. - Google Patents

Description

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CH 685 903G A3

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Description

The present invention relates to a watch case comprising a middle part 1 having an opening defined by an internal face as well as a glass disposed in said opening and fixed to the middle part only by means of glue interposed between the edge of the glass and said internal face.

This type of watch case is particularly advantageous for watch boxes with flat top whose glass is round, but is also suitable for shaped boxes and boxes whose glass is of a shape other than round.

The glasses embedded in a middle part or in a bezel rest on a support surface. The lower periphery of the glass thus rests on a seat formed by the flange, a support ring or other similar element. Such a bearing surface can also be formed directly on the bezel or the middle part, for example by machining. Glass thus set can be held by clamping, gluing, welding, claws, etc.

The resulting assembly is affected by the multiple imperfections present. In almost all these cases, mainly because of manufacturing tolerances, and the accumulation of tolerances (of the seat, glass and glue) it is practically impossible to obtain a perfectly uniform assembly allowing, for example, for a watch case with a flat top, on the upper face of the glass to be precisely parallel to the upper face of the middle. Furthermore, although this phenomenon is particularly visible on watch boxes with a flat top, similar drawbacks also affect the quality of watch boxes with a shaped top.

The main purpose of the present invention is to provide a watch case whose embedded glass is held only by peripheral bonding of its outline. This goal is achieved by the means claimed.

In the case of a watch case with a flat top according to the invention, it is possible to obtain an assembly where the upper face of the glass is precisely parallel to the upper face of the middle part. In the case of a watch case with a non-flat top, a regular and uniform assembly is obtained, without discontinuity or other similar imperfections. The machining of the middle part is very simple and economical given the lack of seat. In the case of a round glass, the middle part, forming a tube of uniform internal diameter, can be machined in the form of a tube whose length corresponds to several times the height of the middle part, the tube being subsequently cut to form thus several shoulders.

Thanks to the performance of current adhesives of known type, it is possible to achieve excellent shear strength, the bonded glass being able to withstand up to 10 atm or even more.

The invention is set out below in more detail, with the aid of the single figure which represents a sectional elevation view of a watch case with caseless base according to the present invention.

The present invention is described by way of an example where the top of the case is flat and the glass is round, but a multitude of other forms of case and glass can be used.

The middle part 1 is preferably of tubular shape, the opening 16 being defined by an internal face 5, substantially parallel to the axis 17 of said opening. According to the illustrated embodiment, the top 9 of the middle part is flat and uniform.

However, the top can also have another shape, forming a simple or complex profile. The tubular shape of the middle has the advantage of allowing serial machining: for example, a tube several centimeters long is machined. The tube is then sectioned in several parts, so as to obtain a multitude of middle parts, where only the machining and / or the finishing of the external diameter then remains to be completed, for example to provide a housing for a fastener 7 of determined shape. The opening 16 can also have another shape, such as for example square, hexagonal, oval, etc. The matching glass has a corresponding outline.

The glass 2, the outline 8 of which is uniform, is arranged in the middle part, preferably so that the upper face 10 of the glass and the top 9 of the middle part are precisely parallel. The upper face 10 can be raised, on a level with or even set back from the top 9 of the middle part. It is advantageous to carry out the po-sage when the two elements are overturned on a flat surface. The support between these two elements is ensured by glue of known type, to one or more components, applied so as to form an adhesive joint 14 extending preferentially over the entire contour 8. Depending on the thickness of the glass or the width of the contact surface, the bonding surface can be very thin and still provide very effective support at pressures that can exceed 10 atm. Since the thermal expansion of the middle part is most of the time greater than that of glass, it does not matter whether the middle part is metallic or ceramic and whether the glass is sapphire or other, it may be advantageous to use a glue, the polymerization of which takes place at a temperature above ambient temperature, for example between 120 ° C. and 220 ° C. Thus, during cooling, there will be a throttling effect which will improve the shear strength of the glass / middle part assembly.

The glued glass then serves as a holding element for the other constituent elements of the watch which come to bear against the glass. The various constituent elements of a watch are then placed in the case in a known manner. In the example illustrated, a casing circle 2 in the shape of an inverted "L", the elongated side of which presses against the internal face 5 of the middle part 1, is placed in the box. The casing ring can be used to hold the other essential elements of the watch such as the dial 3 and the movement 13. The back 6 is fixed against the second face, preferably flat, of the middle part 1, by screwing, or other non-permanent means of assembly.

A chamfer 15 is formed along the line above

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CH 685 903G A3

assembly by the rounded or bevelled corner of the glass 4 and / or the middle 1. This chamfer, of minimal dimension, represents the only discontinuity of the assembly. If the dosage of adhesive is poorly determined, a possible slight excess of adhesive will interfere in this chamfer, which will thus prevent any overflowing beyond the flat surface.

It is therefore understood that the watch case according to the present invention can take a multitude of forms.

For example, a flange 12 (in dotted lines in the figure) can be placed under the glass, being held in place by the underside 10 of the glass and / or by gluing. The flange makes it possible to clearly mark the free height necessary for the hands of the watch. The dial can then be placed against the flange, the other elements of the watch being nested thereafter. The flange 12 can also have sealing functions in cases where the bonding of the glass 4 would not be perfectly waterproof all along the contour 8.

According to another variant, it is possible to carry out metallization at the edge of the glass. In this way, it is possible to hide the glued portion, the possible flange and the edge of the dial.

According to another variant, the internal diameter of the middle part is not uniform, and comprises for example one or more flanges which can be used to fix a casing ring, the dial, etc.

Claims (8)

Claims 1. Watch case comprising a middle part (1) having an opening (16) defined by an internal face (5), a glass (4) disposed in said opening, characterized in that the glass (4) is fixed to the middle only by means of glue interposed between the edge of the glass (4) and said internal face (5). 2. Watch case according to claim 1, in which the opening (16) comprises a virtual axis (17), and in which the portion of the internal face (5) cooperating with the glass (4) is substantially parallel to said axis ( 17). 3. Watch case according to claim 1, wherein the plane formed by the upper surface of the glass (4) and that formed by the top of the middle part (9) are substantially parallel. 4. Watch case according to one of claims 1 to 3, wherein a flange (12) is disposed under the underside (10) of the glass (4). 5. Watch case according to claim 4, wherein said flange (12) is fixed against the internal face (5) of the middle part (1) by gluing. 6. Watch case according to one of the preceding claims, wherein the edge of the upper face (10) of the glass (4) is metallized. 7. Watch case according to one of claims 1 to 6, wherein the glass (4) is round. 8. Watch case according to one of claims 1 to 6, wherein the glass (4) is shaped. 5 10 15 20 25 30 35 40 45 50 55 60 65 4