This application claims priority from European Patent Application No 16160398.0 of Mar. 15, 2016, the entire disclosure of which is hereby incorporated herein by reference.
The invention concerns a watch case comprising a rigid structure, and a resonator component arranged to be rigidly assembled, directly or indirectly, to said structure, said resonator component defining with said structure, when they are assembled to each other in an assembled operating position, a chamber that encloses, between said structure and said resonator component, at least one sealing element comprised in said watch case, said structure and/or said resonator component comprising a groove arranged to receive a gasket comprised in said sealing element, and to prevent the removal of said sealing element from said chamber in said assembled position.
The invention also concerns a musical timepiece comprising a striking-work or tune-playing mechanism arranged to cause to resonate at least one gong or one vibration plate affixed to said structure or to a resonator component of a case.
The invention concerns the field of striking or musical timepieces, such as minute-repeater watches, watches with an alarm function, music boxes and suchlike.
In striking or musical timepieces, particularly minute-repeater watches, vibroacoustic improvements essentially concern the external elements allowing the sound level of the striking-work to be increased, but also the regulating elements, to limit the noise of the mechanism when the striking-work is released and thus to increase the emergence of sound produced by the striking-work, by increasing the ratio between the sound level of the striking-work and that of the noise of the mechanism.
As regards the external elements, radiating crystals or disassociated bezels can optimise the vibrational response of the external elements over a wide frequency band and thereby increase the sound level produced by the radiation of said elements. In order to have a high radiating power over a wide frequency band, the elements must be capable of vibrating freely, and independently of the excitation frequency to which they are subjected.
The vibrational amplitude of the external elements depends on good frequency tuning between the excitation frequency and that of the external elements, but also on good structure-borne sound transfer between the vibration generating element, such as a gong or similar, and a radiating element, such as a bezel/crystal assembly or a case back. The vibrations must therefore propagate easily without being attenuated by intermediate elements between the vibration generating element and the element intended to radiate, or by gaskets required for sealing the timepiece, which may prevent the radiating elements from vibrating freely.
CH Patent 698742B1 in the name of RICHEMONT discloses a device for connecting a striking-work gong to the crystal of a timepiece. The gong is integral with a heel portion secured by a screw to a part of the movement. This screw extends beyond the dial and rests via its end surface on the underside of an annular segment of an annular resilient component integral with the crystal. This annular resilient component has at least four annular segments, each having a rectilinear shape, seen in cross-section. The outer edge of the annular resilient component is intended to be clamped between a bezel and the middle of the timepiece case by means of a sealing gasket. The portion of the annular resilient component that is not underneath the crystal is housed entirely underneath the bezel.
EP Patent Application 2328044A1 in the name of ROLEX discloses a watch case comprising a middle part having at least one opening closed by a bezel and/or a crystal, or by a back cover. At least one of the elements closing the opening is connected to the case middle by a resilient metal member in the form of a ring or endless frame of hollowed cross-section, defined by the profile of a non-rectilinear wall, whose ends are joined to the periphery of the closure element, or respectively of the case middle. The profile of this non-rectilinear wall forms at least one annular fold of parallel orientation to the plane of the opening, this fold being produced by a curvature whose arc describes an angle comprised between 90° and 180°, to allow the closure element freedom of movement with respect to the plane of the opening.
The invention proposes to avoid the strong vibrational attenuation usually caused by the sealing gaskets for the external elements, and to allow some of the external elements, which are intended to radiate, to vibrate freely.
To this end, the invention concerns a watch case.
The invention also concerns a striking or musical timepiece according to claim 11.
Other features and advantages of the invention will appear upon reading the following detailed description, with reference to the annexed drawings, in which:
The invention proposes to make a timepiece comprising sound transmission means enclosed inside a case, and means for radiating the sound vibration towards the user, using some of the elements of the timepiece exterior, while restricting to a maximum the strong vibrational attenuations usually caused by the sealing gaskets of the timepiece exterior, in order to allow those elements of the exterior that are intended to radiate, called here the “radiating element”, to vibrate freely.
In order for the vibroacoustic system formed by the vibration generating element and the radiating element to be efficient, it is important for the radiating element to be able to vibrate freely in its natural vibration modes, which are mainly defined by its fastening system. To prevent the vibrations propagating to the rest of the timepiece exterior, it is important for the contact between the radiating element and the most rigid part of the case, notably a case middle, to be minimal. However, this type of exterior runs counter to a water-resistant construction. The invention optimises the transfer of vibrations, while ensuring the sealing of the timepiece.
The invention is described and illustrated in the particular and non-limiting case of a striking watch. It is directly applicable to a musical watch, to a music box, or other similar timepieces.
In the case of a watch, the assembly formed by the case middle and the back cover is the most rigid element, and is in direct contact with the user. The radiating element is, generally speaking, preferably located opposite the back cover, and advantageously includes at least the bezel or the crystal.
The invention is described for a watch case 100 comprising a rigid structure in turn comprising a middle part. A bezel which, in a conventional manner, carries a crystal, is fastened to this middle part. Those skilled in the art will have no difficulty in transposing this embodiment to a musical watch or similar.
Thus, the invention concerns a watch case 100 comprising a rigid structure 1, and at least one resonator component 2. This at least one resonator component 2 is arranged to be rigidly assembled, directly or indirectly, to structure 1.
Preferably, resonator component 2, even if it comprises a membrane or a component intended to vibrate, comprises at least one part of similar stiffness to that of structure 1, and the fastening is achieved on these rigid parts of resonator component 2 and of structure 1.
Resonator component 2 defines with structure 1, when they are assembled to each other in an assembled operating position, a chamber 4 which encloses, between structure 1 and resonator component 2, at least one sealing element 3 comprised in this watch case 100. This chamber 4 encircles watch case 100. It has a height corresponding to a sufficient end play value J to allow unimpeded vibration at full amplitude of resonator component 2 with respect to structure 1.
Structure 1 and/or resonator component 2 comprises a groove 51, 52 which is arranged to receive a gasket 31, 32, comprised in sealing element 3, and to prevent the removal of sealing element 3 from chamber 4 in the assembled position.
This sealing element 3 must answer an a priori contradictory problem: not to form an impediment to the vibrations of resonator component 2, and to ensure the conventional sealing of a watch under several thousand hectopascals, against water and dust and suchlike. In an advantageous embodiment, sealing element 3 includes at least one gasket 31, 32, whose deformed shape under such external pressure is different from its shape at rest under normal atmospheric pressure. Preferably, this gasket comprises at least one lip 310, which is thinner than the body of the more solid gasket 320, which is used for holding the gasket inside a groove or a housing, said thin lip 310 bears on a flat surface 81, 82, onto which it is pressed further, the higher the external pressure.
According to the invention, watchcase 100 includes at least one protruding relief portion 61, 62, 63, forming part of structure 1 and/or of resonator component 2 and/or of sealing element 3.
More particularly at least structure 1 or resonator component 2 comprises such a protruding portion 61, 62.
More particularly this at least one protruding relief portion 61, 62, 63 is rigid, and which is arranged, in the assembled position, to exert a compression force on at least one gasket 31, 32, facing a median area of the groove 51, 52, which receives gasket 31, 32. Thus, when resonator component 2 is assembled on structure 1, sealing element 3 is compressed between them, and each protruding relief portion compresses a gasket inside a groove, thereby sealing case 100. This manner of assembling a sealing element is unusual, since the grooves usually serve to hold one part of a gasket that has a surface opposite the groove which bears on a smooth opposing surface. Moreover, it is generally sought to avoid the risk of damaging a gasket by pressure on a protruding element.
Therefore, within the scope of the invention, a silicone or similar gasket is preferably chosen, with a very low Shore hardness, preferably less than or equal to 20 Shore A.
Thus, sealing element 3 advantageously includes at least one gasket 31, 32, with a hardness less than or equal to 20 Shore A.
More particularly, each gasket 31, 32 comprised in sealing element 3 has a hardness less than or equal to 20 Shore A.
The system of mechanical fastening between structure 1 and resonator component 2, notably by at least one lug 7, leaves an end play J between structure 1 and resonator component 2. The loss of sealing resulting from end play J required for optimum vibration is thus offset by this particular sealing element 3 according to the invention.
In a particular embodiment, for example as seen in
Naturally, protruding relief portion 61, 62, 63 is devoid of sharp edges and preferably has a curved profile to avoid damaging the gasket. Once mounted, sealing gasket 3 is no longer subjected to any actual motion; its function is to ensure the sealing of the interior of case 100, in particular when resonator component 2 vibrates, this vibration occurring within a well-defined maximum amplitude. Each gasket 31, 32, comprised in sealing element 3, can therefore tolerate this vibration and ensure perfect sealing at all times.
Protruding relief portion 61, 62, can be manufactured integrally with structure 1 or resonator component 2, but it may also be added to one of the latter. In this regard, protruding relief portion 61, 62, 63 may be stiff or elastic, but in the latter case is at least ten times less deformable than the gasket concerned, with equal compression.
In a preferred implementation, and as seen in the Figures, resonator component 2 tends to vibrate along an axis Z substantially perpendicular to the bearing surfaces of gasket or gaskets 31, 32, opposite groove or grooves 51, 52, in a resonance mode called the “piston” mode. Each gasket 31, 32 is thus only stressed in that direction, and with a very restricted amplitude, less than 0.10 mm and usually on the order of a hundredth of a millimeter.
In a first variant, as seen in
In a second variant, as seen in
In a third variant, as seen in
The Figures illustrate a preferred variant wherein each protruding relief portion 62, 61 is a closed rib, whose shape conforms to that of case 100.
In these variants, protruding relief portion 62, 61 is integral with structure 1 or respectively resonator component 2, and is either welded or brazed or machined directly to the element concerned.
It will be noted also that sealing element 3, or one of gaskets 31, 32 comprised therein, is not necessarily an added element, and may be made of silicone directly moulded inside the appropriate groove.
The mechanical connection between structure 1 and resonator component 2 may be achieved in different ways. Preferably, this connection is substantially isolated, such that most of resonator 2 can vibrate as freely as possible between two rigid connections.
These lugs 7 may be screwed in to allow for disassembly, or pressed in, welded, brazed, etcetera.
In a particular embodiment of a watch case 100, and as illustrated by the Figures, structure 1 is a case middle, notably fastened to a back cover 11, and resonator component 2 is a bezel carrying a crystal 9, directly or via a crystal gasket 90. In this regard, in the variant comprising a crystal gasket 90, for crystal 9 to resonate in the best conditions, the material of crystal gasket 90 is chosen in accordance with the same criteria as the gasket or gaskets of sealing element 3, in particular, made of silicone or similar, with a very low Shore hardness, preferably lower than or equal to 20 Shore A.
It is understood that the fastening of crystal 9 with respect to bezel 2 can be achieved in accordance with similar variants, and that resonance can thus combine:
For example,
The invention also concerns a musical timepiece 200, i.e. with a sound, striking, alarm, music box or similar mechanism. This timepiece 200, particularly a watch, includes a striking-work or tune-playing mechanism 300 arranged to cause to resonate, for example via a hammer 301, a pin cylinder, or other similar means, at least one gong 302 or a vibration plate fastened to a structure 1 or to a resonator component 2 of a case 100.
According to the invention, resonator component 2 is arranged to be rigidly assembled to structure 1, by at least one lug 7 allowing vibration of resonator component 2 within a determined frequency range. Resonator component 2 defines with structure 1, when they are assembled to each other in an assembled operating position, a chamber 4 which encloses at least one sealing element 3 between structure 1 and resonator component 2. This sealing element 3 on the one hand, and on the other hand the lug, or the at least one lug 7 form the only mechanical connection between structure 1 and resonator component 2. Sealing element 3 includes one or more gaskets 31, 32, in contact with structure 1 and resonator component 2, and all the gaskets 31, 32, have a hardness less than or equal to 20 Shore A, for minimum damping of the vibration of resonator component 2. More particularly, these gaskets are made of silicone.
In a first embodiment, timepiece 200 includes a case 100, which is a watch case according to any of the variants of
In a second embodiment, at least structure 1 or resonator component 2 includes a groove 51, 52, which is arranged to receive a part of greater cross-section 320, of a gasket 31, 32, comprised in sealing element 3, as seen in
The relative fastening between structure 1 and resonator component 2 can be achieved in the manner described above with one or more lugs 7, and the entire description relating to watch case 100 is applicable to this timepiece 200.
Naturally the first embodiment and the second embodiment can be combined, as in the example of
The vibroacoustic system according to the invention is efficient, since the radiating element, here resonator component 2, can vibrate freely in its natural vibration modes. The contact between the bezel and the case middle is minimal, owing to a design with a bezel fastened to a rigid case middle by lugs or similar means, avoiding direct contact with the bezel over the entire periphery of the case.
The invention can be used with an external element manufactured by electroforming, where, because of the very thin structure of this type of component, a gasket is required in order to resist water pressure without ruining the actual component. In particular, an electroformed bezel or case middle made of gold alloy is well suited to implementation of the invention.
In short, the invention concerns a particular assembly of at least three components of a watch exterior, wherein:
The invention provides significant advantages:
Number | Date | Country | Kind |
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16160398 | Mar 2016 | EP | regional |
Number | Name | Date | Kind |
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5751668 | Eray | May 1998 | A |
6213635 | Savy | Apr 2001 | B1 |
20160058375 | Rothkopf | Mar 2016 | A1 |
Number | Date | Country |
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698 742 | Oct 2009 | CH |
2 328 044 | Jun 2011 | EP |
Entry |
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European Search Report dated Sep. 9, 2016 in European Application 16160398.0, filed on Mar. 15, 2016 (with English Translation of Categories of cited documents and Written Opinion). |
Number | Date | Country | |
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20170269553 A1 | Sep 2017 | US |