Watch dial secured to a bottom plate

An assembly including a watch dial and a bottom plate, the bottom plate being delimited by an upper peripheral rim which is extended downwards by an external peripheral surface, the watch dial being secured to the upper peripheral rim of the bottom plate via at least first and second securing mechanisms, wherein the first securing mechanisms includes a boss provided on the external peripheral surface of the bottom plate, the dial having a peripheral edge via which the dial is held between the head of a nail or a screw and the upper peripheral rim of the bottom plate, the head of the nail or screw being extended by a shank which is housed in the boss of the bottom plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from European Patent Application No. 12176187.8 filed Dec. 7, 2012, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns a watch dial secured to a bottom plate. More specifically, the invention concerns a watch dial secured to a bottom plate via securing means.

2. Discussion of the Background

The technique conventionally used to hold a watch dial on a bottom plate consists in providing the dial with dial feet which are locked by means of corresponding dial keys. One of the drawbacks of this technique is that the dial feet are fragile and they can easily break in the event of a shock. Since the dial feet themselves cannot be repaired, the entire dial has to be replaced, provided that it is still available as a spare part, which is not always the case.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the aforementioned drawbacks in addition to others by providing a watch dial secured to a bottom plate via a new securing means which is both simple and reliable.

The present invention therefore concerns an assembly comprising a watch dial and a bottom plate, the bottom plate being delimited by an upper peripheral rim which is extended downwards by an external peripheral surface, the watch dial being secured to the upper peripheral rim of the bottom plate via at least first and second securing means, said assembly being characterized in that the first securing means comprises a boss provided on the external periphery of the bottom plate, the dial having a peripheral edge via which the dial is held between the head of a nail or a screw and the upper peripheral rim of the bottom plate, the nail or screw head being extended by a shank which is housed in the boss of the bottom plate.

As a result of these features, this invention provides an assembly comprising a watch dial and a bottom plate wherein the peripheral edge of the dial is held between the head of a nail or of a screw and the upper peripheral rim of the bottom plate, the nail or screw head being received in a boss arranged on the external periphery of the bottom plate. The dial is thus immobilised using simple, reliable and very economical means. Where the bottom plate is made of plastic material, the bosses arranged on the external periphery of the bottom plate can be obtained very simply by plastic moulding or injection moulding.

According to a first variant of the invention, the second securing means includes a slot provided on the upper peripheral rim of the bottom plate, with the dial being housed via its peripheral edge in the slot in the bottom plate.

According to a second variant, the second securing means includes a second boss provided on the external periphery of the bottom plate, the head of a second nail or of a second screw holding the peripheral edge of the dial against the upper peripheral rim of the bottom plate, the head of the second nail or of the second screw being extended by a shank which is housed in the second boss of the bottom plate.

According to a complementary feature of the invention, the dial is disposed between a flange and the bottom plate, the nail or the screw being driven or screwed into the flange and sandwiching the flange between its head and shank which is housed in the boss of the bottom plate.

According to yet another feature of the invention, the upper peripheral rim of the bottom plate includes at least one centring stud and the peripheral edge of the dial includes a notch arranged to cooperate with the centring stud.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention proceeds from the general inventive idea which consists in using nails or screws to secure a watch dial to a bottom plate. This securing means is both a simple and thus economical means and immobilises the dial in a perfectly reliable manner. According to another advantage of the invention, the dial does not need to be modified since it is simply held between the head of the nail or of the screw and the upper peripheral rim of the bottom plate. The only particular arrangement concerns the bottom plate which must be provided with as many bosses on its external periphery as there are screw heads. This does not however cause any significant problem, in particular where the bottom plate is made of an injected or moulded plastic material. Indeed, in this case the mould simply needs to be provided with recesses matching the bosses.

A first embodiment of the invention is illustrated inFIGS. 1 to 3. Designated as a whole by the general reference numeral1, the dial is obtained for example from a metal sheet or a plastic sheet. In the example ofFIG. 1, both dial1and bottom plate2are of generally circular shape. It will be clear however that the invention is not limited to this geometry and that dial1and bottom plate2may have any shape, such as, for example, square or rectangular.

Bottom plate2generally takes the form of a ring. It is delimited at the top by a circular peripheral rim4on which dial1will be supported and which is extended towards the bottom by an external peripheral surface6.

As can be seen by examiningFIG. 1, on one location on the length of upper peripheral rim4, bottom plate2is provided with a slot8in the arc of a circle into which peripheral edge10of dial1slides. Slot8thus provides a first holding point along the vertical direction where dial1is held on bottom plate2.

According to the invention, dial1is held on bottom plate2on at least a second point. Therefore, a screw12is used which includes a head14extended by a shank16. Dial1will now be held at one location on the peripheral edge10thereof between head14of screw12and the upper peripheral rim4of bottom plate2. Screw12thus provides a second holding point where dial1is held on bottom plate2both in a vertical direction perpendicular to the plane of dial1and in a radial direction. To hold screw12, a corresponding boss18, into which the shank16of screw12is screwed, is provided on the external peripheral surface6of bottom plate2. Boss18is formed by an excess of material, which is provided locally on the external peripheral surface6of bottom plate2and is sufficient to enable screw12to be screwed therein. Where bottom plate2is made of a plastic material, boss18may be obtained very simply by plastic moulding or injection moulding. In the example shown in the drawing, a centring pin20is provided on boss18. This centring pin20, against which dial1abuts via the peripheral edge10thereof, rises up at the surface of upper peripheral rim4of bottom plate2and is provided to improve the guiding of screw12. As is seen more particularly inFIG. 2, screw12is provided at twelve o'clock and slot8is provided at six o'clock. Screw12and slot8hold dial1perfectly on bottom plate2, so that no other holding means is necessary. For example, at nine o'clock (seeFIG. 3C), dial1simply abuts on bottom plate2.

In the above description, there is only one boss18, intended to act as a seat for a corresponding screw12. It goes without saying that the invention is not limited to this example embodiment and that several bosses and corresponding screws may be provided. Likewise, dial1was described as being secured by means of one or several screws. It is clear that these screws may be replaced by other securing means, such as nails, which will be driven into the bosses.

FIG. 4illustrates a variant of the invention wherein dial1is secured to bottom plate2by means of at least two nails22, or three in the example shown. The corresponding bosses18are provided on the external peripheral surface6of bottom plate2, for example at regularly spaced intervals from each other. Nail22provided at twelve o'clock (FIG. 6A) has a larger head24than the nail22provided at four o'clock (FIG. 6B), the head of these nails being extended by a shank26.

To further improve the orientation of dial1, bottom plate2includes at least one centring stud28on upper peripheral rim4and the peripheral edge10of dial1includes a notch30arranged to cooperate with centring stud28. Finally, to orient dial1in a suitable manner, a mistake-proofing element, such as a lug32, which is provided on the upper peripheral rim4of bottom plate2, for example at six o'clock, is housed in a corresponding housing34arranged on peripheral edge10of dial1.

FIG. 7illustrates another variant wherein dial1is sandwiched between a flange36and upper peripheral rim4of bottom plate2. To hold the assembly formed by flange36, dial1and bottom plate2, nails22are driven into flange36, the shank26of these nails22being housed in corresponding bosses18provided on the external peripheral surface6of bottom plate2. Flange36is thus held between head24of nails22and upper peripheral rim4of dial1and grips dial1. Instead of the nails, screws could be provided which are screwed into flange36and into bosses18of bottom plate2.

FIG. 8illustrates another variant of the invention wherein a securing foot38, which is integral with flange36and which is housed in the corresponding boss18of bottom plate2, sandwiches dial1between flange36and bottom plate2.