Patent Publication Number: US-11644796-B2

Title: Timepiece dial provided with a three-dimensional decoration

Description:
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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    represents a perspective view of a dial base plate, provided with a three-dimensional decoration according to the invention. 
         FIGS.  2   a  and  2   b    represent two exploded views of the set of elements which allow the decoration to be secured to the base plate represented in  FIG.  1   . 
         FIG.  3   a    is a plan view of the decoration secured to the base plate. 
         FIGS.  3   b  and  3   c    are sectional views along sections A-A and B-B shown in  FIG.  3     a.    
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
       FIG.  1    and the exploded views of  FIGS.  2   a  and  2   b    represent a base plate  1  of 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 plate  1  to one or more additional plates. According to other embodiments, the dial comprises only one base plate. A three-dimensional decoration  2  is secured to the base plate and offset away from and above the plate. Decoration  2  may be a decorative element made from a rigid material such as a metal, mother-of-pearl or any other material. Decoration  2  comprises an upper surface  3  intended to be arranged facing the watch crystal and a lower surface  4  intended to be arranged on the dial side. 
     According to the invention, decoration  2  is held in a fixed position with respect to base plate  1 , by means of an assembly of elements which has only one point of attachment to base plate  1 , achieved by a fixing screw  5 , screwed into a threaded hole  6  made in base plate  1 . The other elements of the assembly are visible in  FIGS.  2   a  and  2   b   . It is seen that decoration  2  is supported at two separate support points  10  and  11 , respectively by a support bar  12  and by a support foot  13  ( FIG.  1   ). Support points  10  and  11  are defined as points located on vertical lines which pass through the centre of the means of attachment of foot  13  and of bar  12  to decoration  2 ; examples of these means will be described in detail below. 
     Support bar  12  is a part that comprises at least one inclined or curved central portion, such that the projection of support point  10  in the plane of base plate  1  is away from fixing screw  5 . According to the embodiment represented in the Figures, support bar  12  is a rigid part which takes the form of an inclined arm  18  comprising, at the proximal end thereof, a first plate  14  provided with a through hole  15  and, at the distal end thereof, a second plate  16  also provided with a through hole  17 . First plate  14  is inserted, or in other words, embedded in a cavity  20  of base plate  1 , at the bottom of which lies threaded hole  6 . Fixing screw  5  passes through hole  15  in first plate  14 . Second plate  16  is preferably parallel to first plate  14 . Second plate  16  is inserted, or in other words, embedded in a cavity  21  made in lower surface  4  of decoration  2 . Said cavity  21  is provided with a central arbor  22  which passes through hole  17  in second plate  16 . Second plate  16  is secured to decoration  2  by adhesive bonding or welding. The inclination of arm  18  is such that support bar  12  maintains a fixed distance between base plate  1  and lower surface  4  of decoration  2 . 
     Generally, support foot  13  has a proximal end held in a fixed position in the plane of base plate  1  and a distal end attached to lower surface  4  of decoration  2 , at second support point  11 , the projection of second point  11  in the plane of base plate  1  being away from fixing screw  5  and from the projection of first point  10 . Preferably, the two projections of points  10  and  11  and the centre of fixing screw  5  form a triangle. In the embodiment represented in the Figures, foot  13  includes an arbor  23  which takes the form of a supplementary screw  23  screwed at its distal end into a threaded hole  24  provided in lower surface  4  of decoration  2 , said hole  24  preferably not opening onto upper surface  3  of the decoration. Supplementary screw  23  has at its proximal end a screw head  25  which is embedded in a cavity  26  provided in base plate  1 , which immobilises the arbor in the plane of base plate  1 , with a silicone washer  27  positioned between the bottom of cavity  26  and screw head  25 . 
     Supplementary screw  23  and fixing screw  5  are connected laterally to each other by a spacer  30 , mounted above first plate  14  of support bar  12 . Spacer  30  has a first through hole  31  for the insertion of fixing screw  5  through the top of spacer  30 , and a second through hole  32  next to first hole  31 , second hole  32  allowing the insertion of supplementary screw  23  through the bottom of spacer  30 . When fixing screw  5  is tightened, it secures support bar  12  and spacer  30  to dial base plate  1 . At the same time, spacer  30  keeps head  25  of supplementary screw  23  inside cavity  26 , while forming a lateral connection between fixing screw  5  and support foot  13  (in this case supplementary screw  23 ). A rigid tube  33  surrounds one portion of supplementary screw  23 , tube  33  being pressed between lower surface  4  of decoration  2  and spacer  30  when supplementary screw  23  is tightened. A cavity  35  is provided in lower surface  4  of the decoration for receiving the end of tube  33 . Threaded hole  24 , which receives the end of supplementary screw  23 , is at the bottom of cavity  35 . 
       FIGS.  3   a - 3   c    represent the elements described above in sectional views. In the embodiment represented in the Figures, fixing screw  5  is not covered by decoration  2 . This makes fixing screw  5  easily accessible for tightening the screw. Embodiments in which fixing screw  5  is partially or entirely covered by decoration  2  are not, however, excluded from the scope of the invention. In such cases, lateral access is required to the head of screw  5  by a wrench or key of small dimensions in order to tighten fixing screw  5 . 
     Decoration  2  is secured to base plate  1  by the following steps which start with the assembly of the various elements. Supplementary screw  23  is inserted into hole  32  in spacer  30  and into tube  33 . Support bar  12  is attached to lower surface  4  of decoration  2  at point  11  and supplementary screw  23  is screwed into said lower surface  4  at point  10 . Tube  33  ensures that when supplementary screw  23  is tightened, decoration  2  is held at a fixed distance from spacer  30 . Then, decoration  2 , provided with the assembly of elements, is mounted on base plate  1  by placing screw head  25  inside cavity  26  which contains silicone washer  27  at the bottom of said cavity  26 . 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 screw  5  is inserted into holes  31  and  15  and tightened by being screwed into threaded hole  6  in base plate  1 . 
     This assembly makes it possible, via spacer  30 , to distribute shocks and/or vibrations between fixing screw  5 , support bar  12  and support foot  13 , with vibrations and shocks absorbed by silicone washer  27 . This system also makes it possible to distribute the weight of decoration  2  over these same elements. Consequently, in both cases, the load on fixing screw  5  is diminished and this makes the attachment of a heavy decoration  2  more reliable. 
     Several technical details described for the embodiment represented in the Figures are not limiting for the scope of the invention. For example, foot  13  may have a different shape and be attached to decoration  2  and/or to base plate  1  in an alternative manner, for example by welding or adhesive bonding. It may be an arbor bonded or welded to lower surface  4  of decoration  2  and provided with a portion of increased cross-section which fulfils the same function as screw head  25  of supplementary screw  23 . Tube  33  can be omitted in the latter case. Silicone washer  27  can be made from another material having shock absorber properties. Washer  27  may not be required for some weights and/or materials of the decoration. The fixing of support bar  12  to lower surface  4  of the decoration can be achieved by means other than plate  16 . Plate  14  may also be replaced by an equivalent element which allows support bar  12  and spacer  30  to be secured by screwing to base plate  1