EP1470453B1 - Watch case - Google Patents

Description

The present invention relates to a watch case back and a method of manufacturing a watch case back. The present invention relates in particular to a watch case back whose inner face is provided with a decoration.

The watch cases have a middle and a bottom that can be screwed or clipped to the caseband. The bottom must be open to access the movement of the watch, for example to replace the battery or for repairs or maintenance of the movement. Many luxurious watch cases have a bottom which is aesthetically pleasing on the inside. For example, there are known watch case bottoms whose internal face is provided with a decoration, for example a pattern marked by engraving or guilloche in the thickness of the metal.

Watchbox bottoms are most often made by die stamping. The inner face of the watch case bottoms is generally concave and has recesses or threads for attachment to the middle and to maintain the seal. It is therefore difficult to automate the decoration of this face. For this reason, the decoration of the inner face of the bottom is most often done manually. Guilloche background patterns, much appreciated, are usually made using a special chisel and a small hammer to mark more or less regular circles in the thickness of the bottom. These operations are very expensive.

An object of the present invention is to provide a watch case back and a method of making a watch case back which has the same aesthetic qualities as the known decorated case backs but which can be manufactured for less cost. .

Furthermore, there are already known watches containing an identification element, for example a transponder, searchable by means of an inductive reading device. Transponders are used in particular to store information giving access to protected areas, for example as an identification element in a company or as a cinema entrance ticket or for lifts. It has also already been suggested to include a serial number of the watch in an identification element in the watch. This data can for example be read by the after-sales service to check the series to which the watch belongs. The identification element therefore makes it possible to replace or complete the serial number traditionally engraved on the bottom of the watch cases.

In a watch, the antenna of the transponder is generally mounted just on or under the dial or sometimes in the telescope; these provisions, however, cause significant constraints, given the small volume available in a watch, and do not allow the marking of watches with a metal housing. In addition, the antenna is generally visible, which is unattractive, and is exposed to shocks or vibrations. For these reasons, an arrangement of the transponder against the inner face of the watch bottom would be preferable. This provision is however incompatible with funds of decorated watch boxes. Moreover, the transponder and in particular its antenna may be damaged when the bottom of the box is opened without care.

In particular, these objects are achieved by means of the watch case as defined in the claim.

This solution has the advantage of separating the manufacture of the cover, which frequently requires stamping operations, tapping, etc., the manufacture of the false bottom that requires other operations of stamping simpler (cutting) and operations of decoration. It is thus possible to optimize the processes used for the manufacture of these two elements.

In particular, it is possible to manufacture the false bottom by cutting into a plate of regular thickness previously decorated. The decoration of a plate of regular thickness can be automated and carried out using a machine

It is thus possible to decorate in a single operation a plate for the manufacture of several dozens of fake watches. The decoration may for example be performed by etching in the thickness of the plate.

This solution also has the advantage of allowing to place an electronic identification element between the cover and the false bottom. This identification element can be completely hidden between the lid and the false bottom. It does not harm the internal or external aesthetics of the watch and is perfectly protected from any damage, even if the bottom opens. In addition, the false bottom helps to increase the strength and rigidity of the bottom; it is thus possible to reduce the thickness of the cover, which offers the advantage of facilitating inductive reading through the bottom. This advantage is particularly important in the case of a metal watch case back which significantly attenuates the radio waves transmitted to and from the transponder.

In the prior art are known watches whose bottom includes additional elements. In particular, CH 335610 discloses a watch having a bottom, that is to say a member removably closing the middle part, on the outer side of which is added a plastic lining, intended primarily to protect the watch marks in case of contact with foreign bodies. This lining is however not comparable to the false bottom of the present invention. In particular, this lining is on the outer face of the bottom of the watch and not on its inner face. It can not in any way contribute to the reduction of the costs engendered by the decoration of the internal face of the bottom of the watch.

The patent EP1067442 describes a watch whose bottom is formed of a non-conductive material, for example ceramic or glass, and has on its inner face a coating configured to be decorative or informative.

US 1404656 describes a watch whose box consists of an outer box of precious metal reinforced, inter alia, by an inner box of a less expensive material. The box of this watch, however, has no background allowing easy access to the movement without extracting the latter from the box. In addition, the inner box is completely hidden by the outer box and does not perform any aesthetic function.

The patent US6267499 discloses a watch case comprising a watch case bottom and an intermediate bottom closing the movement and held in place by the pressure exerted by the bottom when the case is closed. The intermediate bottom, however, has no aesthetic function.

The document EP1096641 describes an electronic watch whose bottom is formed by a cover in which is made an opening covered on the side of the outer face of the bottom by a window. In the opening is placed a coil connected to a circuit which is itself placed in the watch case.

• La figure 1 est une vue en coupe d'une plaque brute destinée à la fabrication de plusieurs faux-fonds selon l'invention.
• La figure 2 est une vue en coupe de la même plaque au cours de l'opération de décoration par gravage de la face supérieure.
• La figure 3 est une vue de dessus de la plaque après décoration, montrant un motif guilloché.
• La figure 4 est une vue en coupe de la plaque au cours de l'opération de découpe par étampage.
• La figure 5 est une vue de dessus d'un faux-fond de montre décoré et découpé selon l'invention.
• La figure 6 est une vue en coupe partielle d'une boîte de montre munie d'une première variante de fond de montre selon l'invention.
• La figure 7 est une vue en coupe partielle d'une boîte de montre munie d'une deuxième variante de fond de montre selon l'invention.

The invention will be better understood on reading the description given by way of example and illustrated by the appended figures, among which:

• Figure 1 is a sectional view of a blank plate for the manufacture of several false bottom according to the invention.
• Figure 2 is a sectional view of the same plate during the decoration operation by etching the upper face.
• Figure 3 is a top view of the plate after decoration, showing a guilloche pattern.
• Fig. 4 is a sectional view of the plate during the die cutting operation.
• Figure 5 is a top view of a false watch decorated and cut according to the invention.
• Figure 6 is a partial sectional view of a watch case provided with a first watch base variant according to the invention.
• Figure 7 is a partial sectional view of a watch case provided with a second variation of watch background according to the invention.

Figure 1 shows a plate 1 of regular thickness for manufacturing in a small number of operations a plurality of decorated watch case false-backs. The plate is preferably made of metal, preferably in the same metal as that used for the bottom of the watch.

The visible upper face of the plate is decorated in a single operation, for example by means of a stamp 2 pressed on the entire surface of the plate 1 and provided with a punch 20 (Figure 2). The size of the stamp 2 may correspond to that of the plate 1, as illustrated in FIG. 2, or be smaller and applied in several times. It is also possible to engrave the upper surface of the plate 1 by passing it between two rollers, one of which is provided with a relief pattern, or to apply a decoration on the plate 1 by another method, for example by screen printing, plating, eloxidation, etc. However, it will preferably choose a surface treatment of the plate identical to that used for the other parts of the bottom, so as to make the use of a false bottom as visible as possible.

Figure 3 illustrates the upper face of the decorated plate 1. In this example, the embossed pattern 10 resembles the known guilloche patterns.

The plate 1 is then cut, preferably by means of a punch 3 as illustrated in FIG. 4. It is naturally also possible to cut several false bottoms simultaneously in the same plate, and / or to cut and decorate the plate 1 in a single operation and at way of the same stamp. It is also possible to perform several distinct decoration operations on the same plate 1.

Furthermore, additional machining operations not shown can be performed on the false bottom 11, for example to mill a recess (visible in Figures 6 and 7) for housing an electronic component, for example an element of identification 5 and a coil 6. This recess can also be obtained by stamping. It is also possible to deform the underside of the false bottom by stamping to adapt to the inner shape of the lid.

FIG. 5 illustrates a view from above of a false bottom 11 of a watch decorated by means of a guilloche pattern 10.

Figure 6 illustrates a partial section of a watch case having a middle 7 and a bottom 11, 4 according to a first variant of the invention. The bottom comprises a cover 4 and a false bottom 11 made according to the method described above. The lid and the false bottom are provided with holes for fastening screws 40 to the middle part 7. A seal 70 makes it possible to prevent the infiltration of water between the caseband and the bottom. In this example, an identification element constituted here by a transponder 5 provided with an antenna 6 is housed in a recess between the false bottom 11 and the cover 4. The thickness of the cover 4 is preferably reduced in order to limit attenuation of the electromagnetic field through this wall. Conclusive tests were carried out with a lid thickness of about 5 to 7 tenths of a millimeter depending on the material used. The rigidity and solidity of the bottom is nevertheless guaranteed thanks to the false bottom 11, which can be glued to the lid 4 or simply plated by the screws 40.

The antenna 6 is constituted by a coil formed by winding a copper wire and connected by bonding directly on the lugs of the circuit 5. The circuit 5 can be fixed in the recess by means of a double-sided self-adhesive film stamped to the size of the adhesive housing. The circuit 5 placed on the self-adhesive film is transported by suction to be deposited at the bottom of the housing. We will take care particularly during this operation to avoid breaking the wire of the antenna and if necessary can verify the proper operation of the identification element 5 by reading its contents after installation.

The circuit 5 may further be coated with resin. Conclusive tests were carried out by delivering, by means of a metering device, a precise quantity of very pure epoxy resin. In order to ensure that the resin spreads well by filling the entire recess, a centrifuge or a vibrating machine can be used during polymerization of the resin.

It is particularly important to prevent the rise of the resin during the polymerization breaks the son of the antenna 6. To avoid this risk, we can for example proceed to a slow polymerization by storing the bottom 11, 4 at temperature at least 24 hours or by heating at a moderate temperature, of the order of 35 ° C.

The identification element 5 is preferably electrically powered only by the inductive writing and / or reading-writing device used to access the stored data, without soliciting the battery of the watch. It comprises a not shown modulator-demodulator for receiving and demodulating the signals of the inductive reading-writing device, and for modulating and transmitting the responses. In the case of a metal background, the circuit 5 preferably uses a much lower frequency than those usually employed for standard RFID elements, preferably a frequency below 50 KHz, to allow transmission through the metal. An encryption module and / or electronic signature may also be provided in the circuit 5 in the case where confidential data, for example medical or monetary amounts must be stored in one or more fields of the memory area.

The circuit 5 preferably comprises a not shown memory area including a program area as well as a data area. The watch background can thus be personalized by writing in the data area of the manufacturer's and / or retailer's data (serial number, date of manufacture, batch number, etc.). The personalization can be carried out by the watch manufacturer after mounting the bottom on the watch or more simply by the fund manufacturer before assembly of the watch, on the basis of data and serial numbers provided by the watch manufacturer for example on diskette or via e-mail. The memory area can also be modified by application providers after the sale of the watch, for example to enter access codes to protected areas.

In a preferred embodiment of the invention, the serial number of the watch is further etched on the outer face of the bottom. This feature makes it possible to check the serial number of the watch without a special reading device.

FIG. 7 illustrates a second variant of a watchcase bottom provided with a false bottom 11 according to the invention. In this variant, the lid is provided with a peripheral thread 41 enabling it to be screwed directly into the middle part 7. A seal 42 taken between the middle part 7 and a projection 42 of the lid makes it possible to prevent the infiltration of water. As in the variant above, the false bottom 11 is placed on the cover 4 and fixed for example by gluing. An identification element 5, 6 can be placed between the cover 4 and the false bottom 11.

It will be understood by those skilled in the art that other fasteners of the bottom to the middle part, by clips or by means of screws, may be used in the context of this invention.

Claims (9)

1. Watch case having a middle (7) and a bottom, with:

   a cover (4) that is screwed or clamped into the middle and that defines the outer side of the bottom,

   a false-bottom (11) that is mounted against the inner side of said cover,

   a joint (70) for preventing water infiltrations between the middle and the bottom,

   characterized in that an electronic identification element (5) provided with an antenna is mounted between said cover (4) and said false-bottom (11).
2. Watch case according to the preceding claim, wherein said identification element includes an electronic circuit (5) and said antenna (6), mounted in a hollow between said cover and said false-bottom.
3. Watch case according to claim 2, wherein said electronic circuit (5) is fastened in said hollow by means of a double-sided adhesive.
4. Watch case according to claim 2, wherein said electronic circuit (5) is coated in resin.
5. Watch case according to one of the preceding claims, wherein said false-bottom (11) comprises a decoration (10) on the glass side.
6. Watch case according to claim 5, wherein said decoration (10) is marked in the thickness of said false-bottom (11).
7. Watch case according to one of the preceding claims, wherein said false-bottom (11) is of regular thickness, and wherein said cover (4) has fastening means (40, 42) to a watch case middle (7).
8. Watch case according to one of the preceding claims, wherein said false-bottom (11) is fastened in one piece against said inner side of said cover (4).
9. Watch case according to one of the preceding claims, wherein said cover (4) and/or said false-bottom (11) are of metal.

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