Description BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timepiece comprising a box closed by an ice and containing a clockwork movement intended to drive at least one display mechanism comprising at least one movable member adjacent to an ice capable of being Distort when it is under pressure from the outside environment.
STATE OF THE ART [0002] Timepieces, and in particular those which are of small thickness, systematically pose problems of resistance to mechanical stresses likely to cause the deformation of certain components, in particular the box or the ice .
One of the components whose deformation has already been studied has been the ice which, depending on its thickness, can deform more or less because of the pressure it undergoes from the external environment.
This problem is, for example, present in the field of diving watches, where it is regularly solved by the use of ice sheets of considerable thickness in order to increase their resistance to pressure.
[0005] However, especially when it is a question of producing a timepiece of small thickness, in particular for the purpose of exhibiting a certain elegance, it is not conceivable to use an ice of a significant thickness Which would damage the aesthetic appearance of the timepiece.
[0006] Thus, a disadvantage which can result for timepieces, especially those comprising a thin ice, is that the ice can deform under the effect of a considerable ambient pressure at the point of entry In contact with moving parts such as the road, carrying the minute hand, and disturbing the display of the current time, or even causing damage to the watch movement.
DISCLOSURE OF THE INVENTION A principal object of the present invention is to propose a timepiece construction comprising an ice of suitable thickness and in which the application of a large ambient pressure does not lead to a disturbance Of the display of the time due to the deformation of the ice.
To this end, the present invention relates more particularly to a timepiece, characterized in that the watch movement has at least one frame element adjacent to the window, this frame element and the mobile element being arranged Relative to the glass in such a manner that the frame element defines an abutment for the ice in the event of deformation of the latter in order to prevent it from coming into contact with the movable member.
[0009] By virtue of these characteristics, the glass can have a thickness adapted to the aesthetic requirements of the timepiece without compromising its proper functioning in the event of excessive ambient pressure.
Advantageously, the watch movement has at least two frame elements adjacent to the glass and arranged to define stops for the ice in the event of deformation of the latter.
Furthermore, the frame element or elements preferably have at least two points capable of defining stops for the crystal and substantially diametrically opposite one another with reference to an axis of rotation of the movable member.
Alternatively, provision may be made for the frame element (s) preferably to have at least three points capable of defining stops for the ice and distributed in a substantially homogeneous manner with reference to an axis of rotation of the mobile member.
[0013] According to a preferred embodiment, the at least one frame element comprises at least one bridge.
In this case, the timepiece preferably comprises a plate on which the bridge is arranged, so as to be located between the plate and the glass.
[0015] According to additional preferred features of the present invention, the box comprises a bottom with which the plate is made in one piece.
BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the present invention will become more clearly apparent upon reading the detailed description of a preferred embodiment which follows, with reference to the accompanying drawings, given by way of non- And in which: FIG. 1 shows a simplified top view of a timepiece according to a preferred embodiment of the invention; FIG. 2 shows a cross-sectional view of the timepiece of FIG. 1, according to the plane of section 11 - II of FIG. 1, and FIG. 3 shows a plan view similar to that of FIG. 1 on which particular features of the present invention are made more visible.
Mode (s) of realization of the invention [0017] FIG. 1 shows a simplified top view of a timepiece 1 according to an illustrative and non-limiting embodiment of the invention. This view makes it possible to appreciate the general appearance of the timepiece 1 and more particularly the fineness of its lines.
The timepiece 1 is of the wristwatch type, by way of non-limiting illustration, and comprises a box 2 provided with horns 4 intended to be made integral with the ends of a bracelet (not shown). As will become clearer from the remainder of the description, the box 2 is here of the bottom-case type, in a non-limiting manner.
[0019] A winding stem (not visible) carrying a winding and setting ring 6 at its end situated outside the box 2 is provided in a conventional manner.
The box 2 is closed by a bezel 7 carrying a crystal 8 (visible in FIG. 2) and houses a watch movement of the mechanical winding type, in a non-limiting manner. The glass 8 may for example be glued to the bezel 7. This watch movement is mounted upside down here, ie in the opposite direction to the most common sense. More precisely, it comprises a plate 10 arranged at the bottom of the box as will be more clearly apparent from the detailed description of FIG. 2, while bridges are assembled on the plate, being located on the side of the glass 8.
[0021] A large bridge 12 of the winding and setting-up wheels extends over the right-hand part of the plate in FIG. 1, substantially between the noon and six o'clock positions. The latter is held integral with the plate 10 by means of two screws 14.
[0022] A finishing train bridge 16 is arranged substantially between the six o'clock and seven o'clock positions.
[0023] Finally, a third balance bridge 18, or rod, is arranged substantially between the positions 10 hours and 8 hours.
The timepiece 1 also comprises display elements for the current time, in particular the hour and minute hands 22, arranged to rotate above a main dial 24 having a position Eccentric with respect to the box 2, substantially between the positions of ten hours and eleven hours. The dial 24 is made integral with the plate 10 by means of screws 26. A secondary dial 28 is arranged at the periphery of the main dial 24, being held between it and the plate 10 by a portion (reference numeral 30 in FIG. 2) extending beneath the main dial 24.
[0025] It can be seen from FIG. 1 that the box 2 has an important opening, that is to say that the diameter of the glass 8 represents a significant fraction of the diameter of the box 2. Also, insofar as the timepiece is intended to present A small thickness, the glass 8 necessarily has a measured thickness and is therefore subject to deformation when it is subjected to a large external pressure, or even if it is subjected to an impact.
[0026] FIG. 2 shows a cross-sectional view of the timepiece 1 along the sectional plane 11 - II of FIG. 1, and makes it possible to better appreciate the consequences of an excessive deformation of the ice 8.
[0027] The section in FIG. 2 passes through the median planes of the mobiles carrying the hour and minute hands 22.
It will be seen from this figure that the plate 10 is made in one piece with the bottom of the box 2. The bottom presents machining and drilling making it possible to place different components of the watch movement therein.
Thus, more particularly, a hole 32 formed in the plate 10 on the central axis of the dial 24 makes it possible to accommodate a stud 34 bearing a roadway 36 and an hour wheel 38, carrying themselves, respectively, The hands of the minutes 22 and of the hours 20.
[0030] The view in FIG. 2 makes it possible to illustrate very clearly the risk, if a high external pressure on the ice 8 is applied, that the latter comes into contact with the roadway 36.
By way of example, it will be noted that the nominal distance between the glass 8 and the top of the roadway 36 could be of the order of 0.2 mm. Thus, taking into account manufacturing and assembly tolerances, this distance could be reduced to about 0.12 mm. At the same time, a sapphire crystal having a diameter of the order of 30 mm and a thickness of the order of 0.5 mm could be deformed by having a deformation amplitude at its center of the order of 0, 15 mm, under the effect of applying a pressure of the order of 2 bars.
It can be deduced that, in the case of a roadway arranged in the center of the box, there is a risk of collision of the ice with the roadway, which could not only disrupt the precision of the movement of the watch movement but possibly Damage it.