Timepiece dial provided with a three-dimensional decoration

A dial for a timepiece, such as a watch, includes at least one three-dimensional decoration offset away from a base plate which forms part of the dial. The decoration is mounted on the base plate by an assembly of elements including a fixing screw, a support bar including a proximal end secured to the base plate by the fixing screw and a distal end attached to a first point of the lower surface of the decoration, a support foot including a proximal end held in a fixed position in the plate of the base plate and a distal end attached to a second point of the lower surface of the decoration, and a spacer which forms a lateral connection between the fixing screw and the support foot, the spacer being secured with the support bar to the base plate by the fixing screw.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No. 19163395.7 filed on Mar. 18, 2019, the entire disclosure of which is hereby incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of external components for horology, more particularly to timepieces comprising a dial that bears a three-dimensional decoration.

STATE OF THE ART

To enhance the conventional display components, some timepieces comprise, between the base plate of the dial and the crystal, a decoration giving a particular character to the timepiece. The decoration includes, depending on the case, an automated figure, a motif in relief or a combination of the two. The decorations can be made with precious, fragile materials, such as glass or mother-of-pearl, or with heavier materials such as metal.

EP Patent Application No. 3339979A discloses a dial provided with a three-dimensional decoration, offset away from the dial base plate and secured to the base plate via at least one foot. The decoration is mounted on said foot by means of a pipe arranged to be pressed onto an upper step portion of the foot and resting on a shoulder of said foot. This type of attachment is stable but for decorative pieces of significant dimensions and weight, a plurality of feet is necessary, which increases the complexity of the dial.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a dial provided with a three-dimensional decoration secured to the dial by a means of attachment which increases the mechanical stability and the resistance of the decoration to shocks and vibrations, compared to existing solutions.

This object is achieved by a dial and by a timepiece according to the annexed claims.

Other features and advantages of the present invention will appear in the following description of preferred embodiments, given by way of non-limiting example, with reference to the annexed drawings.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG.1and the exploded views ofFIGS.2aand2brepresent a base plate1of a watch dial according to one embodiment. This is a plate that forms only one part of the dial, the latter being made by assembling plate1to one or more additional plates. According to other embodiments, the dial comprises only one base plate. A three-dimensional decoration2is secured to the base plate and offset away from and above the plate. Decoration2may be a decorative element made from a rigid material such as a metal, mother-of-pearl or any other material. Decoration2comprises an upper surface3intended to be arranged facing the watch crystal and a lower surface4intended to be arranged on the dial side.

According to the invention, decoration2is held in a fixed position with respect to base plate1, by means of an assembly of elements which has only one point of attachment to base plate1, achieved by a fixing screw5, screwed into a threaded hole6made in base plate1. The other elements of the assembly are visible inFIGS.2aand2b. It is seen that decoration2is supported at two separate support points10and11, respectively by a support bar12and by a support foot13(FIG.1). Support points10and11are defined as points located on vertical lines which pass through the centre of the means of attachment of foot13and of bar12to decoration2; examples of these means will be described in detail below.

Support bar12is a part that comprises at least one inclined or curved central portion, such that the projection of support point10in the plane of base plate1is away from fixing screw5. According to the embodiment represented in the Figures, support bar12is a rigid part which takes the form of an inclined arm18comprising, at the proximal end thereof, a first plate14provided with a through hole15and, at the distal end thereof, a second plate16also provided with a through hole17. First plate14is inserted, or in other words, embedded in a cavity20of base plate1, at the bottom of which lies threaded hole6. Fixing screw5passes through hole15in first plate14. Second plate16is preferably parallel to first plate14. Second plate16is inserted, or in other words, embedded in a cavity21made in lower surface4of decoration2. Said cavity21is provided with a central arbor22which passes through hole17in second plate16. Second plate16is secured to decoration2by adhesive bonding or welding. The inclination of arm18is such that support bar12maintains a fixed distance between base plate1and lower surface4of decoration2.

Generally, support foot13has a proximal end held in a fixed position in the plane of base plate1and a distal end attached to lower surface4of decoration2, at second support point11, the projection of second point11in the plane of base plate1being away from fixing screw5and from the projection of first point10. Preferably, the two projections of points10and11and the centre of fixing screw5form a triangle. In the embodiment represented in the Figures, foot13includes an arbor23which takes the form of a supplementary screw23screwed at its distal end into a threaded hole24provided in lower surface4of decoration2, said hole24preferably not opening onto upper surface3of the decoration. Supplementary screw23has at its proximal end a screw head25which is embedded in a cavity26provided in base plate1, which immobilises the arbor in the plane of base plate1, with a silicone washer27positioned between the bottom of cavity26and screw head25.

Supplementary screw23and fixing screw5are connected laterally to each other by a spacer30, mounted above first plate14of support bar12. Spacer30has a first through hole31for the insertion of fixing screw5through the top of spacer30, and a second through hole32next to first hole31, second hole32allowing the insertion of supplementary screw23through the bottom of spacer30. When fixing screw5is tightened, it secures support bar12and spacer30to dial base plate1. At the same time, spacer30keeps head25of supplementary screw23inside cavity26, while forming a lateral connection between fixing screw5and support foot13(in this case supplementary screw23). A rigid tube33surrounds one portion of supplementary screw23, tube33being pressed between lower surface4of decoration2and spacer30when supplementary screw23is tightened. A cavity35is provided in lower surface4of the decoration for receiving the end of tube33. Threaded hole24, which receives the end of supplementary screw23, is at the bottom of cavity35.

FIGS.3a-3crepresent the elements described above in sectional views. In the embodiment represented in the Figures, fixing screw5is not covered by decoration2. This makes fixing screw5easily accessible for tightening the screw. Embodiments in which fixing screw5is partially or entirely covered by decoration2are not, however, excluded from the scope of the invention. In such cases, lateral access is required to the head of screw5by a wrench or key of small dimensions in order to tighten fixing screw5.

Decoration2is secured to base plate1by the following steps which start with the assembly of the various elements. Supplementary screw23is inserted into hole32in spacer30and into tube33. Support bar12is attached to lower surface4of decoration2at point11and supplementary screw23is screwed into said lower surface4at point10. Tube33ensures that when supplementary screw23is tightened, decoration2is held at a fixed distance from spacer30. Then, decoration2, provided with the assembly of elements, is mounted on base plate1by placing screw head25inside cavity26which contains silicone washer27at the bottom of said cavity26. The silicone washer has a shock and vibration absorber function and offsets differences in tolerances in the superposed elements while providing support on the dial. Finally, fixing screw5is inserted into holes31and15and tightened by being screwed into threaded hole6in base plate1.

This assembly makes it possible, via spacer30, to distribute shocks and/or vibrations between fixing screw5, support bar12and support foot13, with vibrations and shocks absorbed by silicone washer27. This system also makes it possible to distribute the weight of decoration2over these same elements. Consequently, in both cases, the load on fixing screw5is diminished and this makes the attachment of a heavy decoration2more reliable.

Several technical details described for the embodiment represented in the Figures are not limiting for the scope of the invention. For example, foot13may have a different shape and be attached to decoration2and/or to base plate1in an alternative manner, for example by welding or adhesive bonding. It may be an arbor bonded or welded to lower surface4of decoration2and provided with a portion of increased cross-section which fulfils the same function as screw head25of supplementary screw23. Tube33can be omitted in the latter case. Silicone washer27can be made from another material having shock absorber properties. Washer27may not be required for some weights and/or materials of the decoration. The fixing of support bar12to lower surface4of the decoration can be achieved by means other than plate16. Plate14may also be replaced by an equivalent element which allows support bar12and spacer30to be secured by screwing to base plate1