CH708622B1 - Process for improving the acoustic level of a timepiece and timepiece with an improved acoustic level. - Google Patents

Abstract

The invention relates to a method for improving the acoustic level of a musical or striking timepiece (1), comprising at least one vibration generator (2) arranged to vibrate at its own frequencies in a range of 1 kHz. at 6 kHz, this vibration generator (2) comprising in particular timbres or blades of a keyboard. A casing (3) or / and a movement (17) included in said timepiece (1) is modified by the integration or addition of at least one radiating element (4) arranged to vibrate at its own frequency. fundamental tuned with one of said natural frequencies of said at least one vibration generator (2), with a frequency difference between said two natural frequencies less than or equal to the ratio between the fundamental natural frequency of said radiating element and the inverse of the factor of quality of said radiating element, or with a frequency difference between said two natural frequencies less than or equal to 100 Hz. The invention also relates to a musical or striking timepiece (1) obtained by this method, in particular a striking watch or / and musical box. This timepiece (1) comprises a casing (3), a movement (17) and at least one vibration generator (2) arranged to vibrate at its own frequencies in a range of 1 kHz to 6 kHz, this generator of vibrations (2) comprising in particular gongs or blades of a keyboard, said casing (3) or said movement (17) comprising at least one radiating element (4) arranged to vibrate and radiate at its fundamental natural frequency tuned with the one of said natural frequencies of said at least one vibration generator (2).

Description

Field of the invention

The invention relates to a method of improving the acoustic level of a musical or ringing timepiece, comprising at least one vibration generator arranged to vibrate at its own frequencies in a range of 1 kHz to 6 kHz , this vibration generator comprising in particular gongs or blades of a keyboard.

[0002] The invention also relates to a musical or ringing timepiece obtained by this method of improving the acoustic level, in particular a ringing watch or / and a musical box.

The invention relates to the field of timepieces, and more particularly timepieces comprising means for generating vibrations in the audible soundtrack, in particular striking watches and music box watches.

Background of the invention

Among the complication timepieces, striking watches are particularly popular. However, their small volume often limits the sound emission, and the user must pay special attention to hear the sound message properly.

We know specific positions of the watch acting as a resonance box, on which the user places his watch when he wishes to hear more of the sound produced by the watch, and which do not fall within the scope of the present invention.

[0006] Boxes or cases are known comprising resonance chambers on which are mounted the sound production devices, timbres or keyboards, as in document FR 2 777 095 A1 in the name of CHRISTOPHE CLARET SA, with, in some variants, membranes placed in contact with the walls of such resonance chambers, which chambers consume a large part of the internal volume available in the case or the middle part.

[0007] Document EP 2 034 376 B1 in the name of ROTH ET GENTA SA attempts to solve this problem of bulk, by proposing a thin middle part as a resonator, comprising lugs for fixing the gongs or the like.

[0008] Application CH 645 236 G in the name of BOUILLE describes a box comprising peripheral fins intended for mechanical fasteners: because of this specific function, they have increased mechanical rigidity. Their geometric shapes, fixings and orientations are well defined and acoustically inefficient, and these fins could not act as external sound resonators.

Acoustic generators are also known where the sounds are produced by a membrane which vibrates an elastic blade, and whose vibrations are maintained by an electromagnetic transducer, as in documents CH 497 760 and CH 497 017 in the name of SPADINI , which are bulky and require an electrical circuit.

To improve the acoustic level of a striking watch, it is necessary to optimize the elements which constitute the casing of the watch, so that it radiates the frequencies generated by the striking system, it is that is to say in general the natural frequencies of the blades of a keyboard, or the natural frequencies of a timbre of a minute repeater. To obtain a rich sound (in the case of a minute repeater) or a sound of uniform intensity whatever the notes played (in the case of a music box-type watch), the casing must be able to respond to a wide band of frequencies between 1 kHz and 6 kHz, which are the frequencies for which the perception of the human ear is optimal.

However, because of its size, its shape and its rigidity, the casing of a watch mainly has specific modes at high frequencies. In this case, the dressing filters, more than it radiates them, the frequencies of the ringtone or of the melody.

It is known to optimize the covering so that it radiates a single given frequency in the frequency band of interest (1 kHz-6 kHz), as in the document FR1136675A in the name of Gebrueder JUNGHANS AG which describes the use of a standard membrane for a striking clock, or for the covering to radiate several modes in the frequency band of interest (1 kHz-6 kHz), as in document EP 2 461 219 A1 in the name of MONTRES BREGUET SA communicating on the use of a spatially inhomogeneous membrane optimized, or in patent EP 2 367 079 B1 in the name of MONTRES BREGUET SA which describes a solution in which the watch crystal constitutes the vibrating and radiating organ , thanks to a particular arrangement of the fixing of the crystal on the bezel.

In the state of the technology, and for traditional constructions of watches, it is however impossible to obtain acoustic resonances of the covering at a frequency below 1500 Hz, because the covering components have the function principle of guaranteeing the protection of the movement and, generally, the water resistance of the watch, and must therefore be sufficiently rigid and thick. For the same reason, it is impossible to greatly increase the number of acoustic dressing resonances in the frequency band of auditory interest (from 1 kHz to 6 kHz), which considerably limits the acoustic level and the richness of the sounds emitted. and melodies played.

Summary of the invention

The invention proposes to provide an improvement in the acoustic level and the richness of the sound and the melodies played by a timepiece, in particular a striking or musical watch, without altering the quality of the sound emitted by the mechanism or transmitter circuit. The invention also makes it possible to selectively filter part of the noise produced by the mechanism of a timepiece, in particular a watch.

Innovatively, the invention integrates additional radiating elements to a conventional covering, these additional elements are dimensioned so that the frequencies of their first natural modes, (hereinafter called fundamental natural frequencies), are granted to the natural frequencies of the vibration generator of the timepiece, in particular a watch, in particular a gong, or of the blades of a keyboard to improve the overall acoustic level of the timepiece, in particular a watch. The geometries (surface, thickness, shape) of these additional elements allow the formation of radiating acoustic waves.

[0016] Thus, the classic casing can be sized according to the constraints imposed by the watch design, by the style study, by the size of the movement, and to meet specifications such as water resistance and resistance to shocks, and this without particularly worrying about the radiating power of this covering, which is improved, according to the invention, by the addition of these vibrating elements (hereinafter called “radiating elements”), dimensionally optimized for the radiant function only sound.

To this end, the invention relates to a method of improving the acoustic level of a musical or striking timepiece, comprising at least one vibration generator arranged to vibrate at its natural frequencies in a range of 1 kHz to 6 kHz, this vibration generator comprising in particular gongs or blades of a keyboard, characterized in that a casing or / and a movement included in said timepiece is modified by the integration or addition of at least one radiating element arranged to vibrate at its fundamental natural frequency tuned with one of said natural frequencies of said at least one vibration generator, with a frequency difference between said two natural frequencies less than or equal to the ratio between the natural frequency fundamental of said radiating element and the inverse of the quality factor of said radiating element, or with a frequency difference between said two natural frequencies less than or equal to 100 Hz.

The invention also relates to a musical or striking timepiece obtained by this method of improving the acoustic level, in particular a striking watch or / and a musical box, characterized in that it comprises a cover, a movement and at least one vibration generator arranged to vibrate at its own frequencies within a range of 1 kHz to 6 kHz, this vibration generator comprising in particular the gongs or blades of a keyboard, said casing or said movement comprising at least one radiating element arranged to vibrate and radiate at its fundamental natural frequency tuned with one of said natural frequencies of said at least one vibration generator.

Brief description of the drawings

Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows, with reference to the accompanying drawings, where: FIG. 1A represents, in a diagrammatic and partial manner, and in perspective, a timepiece constituted by a watch, optimized according to the invention by the integration of radiating elements comprising radiating plates, integrated into the middle part and into the bezel of the watch; FIG. 1B represents, schematically, and in perspective, a watch, optimized according to the invention, having radiating elements of different sizes with different attachment conditions, developing outside the watch case; FIG. 2A represents, schematically, and in perspective, a particular variant embodiment of the invention, with four radiating elements fixed to the watch case and substantially radial, with the main vibrating surfaces facing the user; FIG. 2B represents, schematically and in section along a plane passing through a main axis, the watch of FIG. 2A, comprising sound generators and radiating elements according to the invention; FIG. 2C shows, similarly to FIG. 2B, another variant with radiating elements outside and inside the watch case; FIG. 3 represents a diagram with, on the abscissa of the frequencies in Hz, and on the ordinate, the sound level in dB, measured at 5 cm from the watch on the main axis of the watch, for the same watch casing, in continuous line according to a conventional embodiment, and in broken lines according to a first optimized embodiment where this same covering is equipped with radiating elements according to the invention; this diagram is shown in an application where the first natural mode of the radiating elements is at 1350 Hz. The diagram shows the resonance effect of the radiator at the desired frequency and the anti-resonance effect (filtering, sound reduction) in the rest of the frequency band; FIG. 4 represents, in a manner similar to FIG. 2A, the same covering, according to a second optimized embodiment where it is equipped with radiating elements having a first specific mode at 2210 Hz; FIG. 5 represents, in the form of a block diagram, a timepiece comprising an optimized casing according to the invention.

Detailed description of the preferred embodiments

The invention relates to the field of timepieces, and more particularly timepieces which include sound emission means, and more particularly striking watches and music box watches, that the musical watches will be called hereinafter interchangeably, and it proposes to provide means for increasing the acoustic level and the sound volume.

The present description relates more particularly to such musical watches. Those skilled in the art will know how to use the invention, as described, for timepieces or watches that are not musical or without ringing, for example with the aim, as the case may be, of making everything audible to the user. or part of the sound generated by the watch mechanism, or conversely to filter and make inaudible the noise generated by the mechanism (by exploiting the phenomenon of antiresonance introduced by a vibratory coupling between, on the one hand, elements radiating elements according to the invention and described below, and on the other hand the rest of the watch casing).

The invention relates to an improvement relating both to the design of musical watches and to the modification of existing musical watches, for the optimization of their acoustic level.

Thus, the invention relates to a method of improving the sound emission level of a timepiece 1, or of a musical or striking timepiece, comprising at least one vibration generator 2 This vibration generator 2 can include a timbre, a keyboard, a membrane, a resonance box, or the like, vibrating at specific natural frequencies in the acoustically effective band, ie frequencies between 1 kHz and 6 kHz. The vibrational frequencies of a radiating element, which is described below, are referred to here as “fundamental natural frequencies of the radiating element”.

This vibration generator 2 is carried by a casing 3 of the timepiece 1 or by a movement 17 of this timepiece 1.

According to the invention, the natural frequencies of the at least one vibration generator 2 are determined precisely (FEM simulation or the like), and we integrate or add to the design and construction of the casing 3 or / and of the movement 17, and in particular but not limited to outside this covering 3 or / and this movement 17, at least one radiating element 4.

This radiating element 4 vibrates at a fundamental natural frequency which is tuned with one of the natural frequencies of the at least one vibration generator 2, with a frequency difference less than or equal to the ratio between the fundamental natural frequency of the radiating element and the inverse of the quality factor of the radiating element 4, or with a frequency difference between the two natural frequencies less than or equal to 100 Hz.

In a particular implementation, the fundamental natural frequency is tuned with one of the natural frequencies of the at least one vibration generator 2, with a frequency difference less than or equal to the lowest value between, of a share the ratio between the fundamental natural frequency of the radiating element and the inverse of the quality factor of the radiating element 4, or with a frequency difference between the two natural frequencies less than or equal to 100 Hz.

By "tuning" is meant here the fact of adjusting a frequency to a substantially equal frequency, with a frequency difference less than a calculated or predetermined value: the term "substantially equal" depends on the width of the resonance vibro-acoustics of the radiating element, therefore of its quality factor.

The fundamental natural frequency of the radiating element 4 is tuned to the natural frequency of at least one vibration generator 2. This tuning rule can be formulated otherwise by saying that the fundamental natural frequency of the radiating element is substantially equal to the natural frequency of at least one vibration generator 2, the difference between the two frequencies being less than the ratio between the fundamental natural frequency of the radiating element and the inverse of the quality factor of the radiating element 4.

It should be understood that the term "tune" used in the present description refers to the vibro-acoustic resonance faculty of the radiating element 4, when it is requested at the vibration frequency of the at least one. vibration generator 2. This term therefore does not take into account a musical characteristic at all.

It is therefore possible to tune a natural frequency of at least one vibration generator 2 to a fundamental natural frequency of the radiating element 4, with a frequency difference less than or equal to 100 Hz, if the factor The quality of the radiating element is equal to or less than 10, which is generally possible, as shown in Figures 3 and 4.

The quality factor Q is defined as the ratio between, on the one hand the mechanical energy stored in a vibrating element (total elastic energy and kinetic energy), and on the other hand the energy lost by damping during a complete oscillation.

The quality factor is also defined, in an equivalent manner, as the ratio between the frequency of the natural mode of vibration of the vibrating element and the bandwidth of the resonance of this vibrating element. The vibrating element responds (therefore it begins to vibrate strongly) if an excitation is imposed on it with a frequency which is in a frequency interval around the frequency of the natural mode of vibration: this frequency interval is the bandwidth (the width peaks in Figures 3 and 4). Mathematically: Q = f / (f2-f1), f1 and f2 defining the extremes of the frequency interval.

The frequency deviation from the natural frequency of at least one vibration generator 2, on which we want to agree, is therefore less than or equal to the ratio between the fundamental natural frequency of the radiating element and l 'inverse of the quality factor of the radiating element 4.

By default one can take as the maximum value of this frequency difference the value of 100 Hz.

This definition takes into account the fact that the quality factor Q of the generation element is always between 5 and 100 times greater than that of the radiating element, and it is generally between 8 and 30 for the mechanisms which relate to the invention.

So the radiating element resonates if it is requested by a frequency vibration of the generator fA, which is tuned according to the definition above, or substantially equal to use the horological vocabulary, at its fundamental frequency, as shown by example in Figures 3 and 4, where the frequency response interval of the radiating element is of the order of 100 Hz: the difference between the frequency of the radiating element and the frequency of the generating element can therefore be 100 Hz.

It is not necessary that all the vibration frequencies (an infinite number of harmonics) of the radiating element are substantially equal to one of the vibration frequencies of the generating element.

On the contrary, according to the most advantageous variant of the invention, a plurality of radiating elements, in number N, is fixed to the case of the timepiece 1, in particular a watch. N is the number of vibration modes of the generation element that one wishes to radiate, and each radiating element has a fundamental mode of vibration whose frequency is substantially equal to the frequency of one of the modes of the generation element .

For example, for a gong having four modes of vibration in the frequency interval between 1 kHz and 6 kHz, four radiating elements 4 formed of radiating plates are added outside the case of the timepiece 1 , in particular a watch, each of these four plates having a fundamental natural mode of vibration of frequency substantially equal, according to the definition above, to one of the frequencies of vibration of the gong between 1 kHz and 6 kHz.

In another example, for a keyboard having ten blades (each having a mode of vibration in the frequency interval between 1 kHz and 6 kHz), ten radiating elements 4 formed of radiating plates are added to the outside of the case of the timepiece 1, in particular a watch, each of these ten plates having a fundamental natural mode of vibration of frequency substantially equal to one of the frequencies of vibration of the blades of the keyboard.

Thus, to improve the radiation of a timepiece 1, in particular a watch, those skilled in the art implements a method comprising, to determine the number of radiating elements 4, the following steps: determining the number N of modes of vibration of the generating element, formed by the vibration generator 2, which it is desired to radiate; equipping the timepiece 1 with a number N of radiating elements 4, each radiating element 4 fixed to the outside of the case of the timepiece 1; ensure that each radiating element 4 has the sole function of radiating; preferably orient each radiating element 4 in a particular listening direction for which the timepiece 1 is designed, in which particular listening direction is supposed to be a user listening to the ringing or / and the music emitted by the part watchmaking 1; optimizing each radiating element 4 to ensure that the frequency of its fundamental eigenmode is tuned substantially equal to that of one of the eigenmodes of vibration of the generator element; ensure that each radiating element 4 is distinct from the generating element (their frequencies are different except for the substantially equal frequency that one wishes to radiate, their quality factors are different, there is no phase relationship between the vibration of the radiating element 4 and the vibration of the generating element).

The radiating elements 4 according to the invention have a radiating function if they are positioned outside the case of the timepiece 1, in particular a watch; if they are placed inside, their function is rather to filter (reduce noise) at the frequency considered.

This radiating element 4 and its mechanical connections to the timepiece 1 are numerically dimensioned to present a natural mode of vibration whose frequency is tuned, to less than 100 Hz, with at least one of the natural frequencies of the generator, and whose spatial distortion allows the generation of a radiant acoustic wave. The conditions radiating from structures are presented for example in the work [C. Lesueur, “Acoustic radiation of structures: vibroacoustics, fluid-structure interactions”, Editions Eyrolles, 1988].

Preferably, the trim 3 or / and the movement 17 is modified by integrating or adding a plurality of such radiating elements 4, each introducing a tuned fundamental natural frequency, at less than 100 Hz , with one of the frequencies of the generator of the vibration generator.

In a particular implementation of the invention, at least part of these radiating elements 4 is chosen with different fundamental natural frequencies.

In another particular implementation of the invention, at least part of these radiating elements 4 is chosen with equal fundamental natural frequencies.

We understand that we can, again, mix these two embodiments of the invention, by choosing several groups of radiating elements 4, each group consisting of radiating elements 4 tuned to the same fundamental natural frequency , and the fundamental eigenfrequencies of the different groups being different from each other.

In an advantageous embodiment, one chooses, within a range of frequencies given in the range audible by the human ear, and for each of the natural frequencies of at least one vibration generator 2, at least one such radiating element 4 with a fundamental natural frequency tuned with one of the natural frequencies of at least one vibration generator 2.

Advantageously, at least one such radiating element 4 is produced with a main vibrating surface 6 which is oriented in a preferential direction, in particular the main axis of the watch corresponding to the pivot axis of the hands, to promote diffusion sound towards the user, in particular through the cover 3.

The use of radiating elements 4 should not complicate the handling of the components of the timepiece, in particular a watch, during its assembly or its maintenance. Also, preferably, and in a nonlimiting manner, at least one such radiating element 4 is secured with a middle part 5 that the cover 3 comprises, or with a box 10 that the cover 3 comprises, or with a bezel 11 that wears such a caseband 5, or with a plate 14 which the timepiece 1 comprises. Advantageously, at least one such radiating element 4 is arranged outside the caseband 5, or inside the case 10, of so that these radiating elements 4 are not in direct contact with the user.

To obtain good vibration of each radiating element 4, at least one said radiating element 4 is connected to the middle part 5 or to the box 10 by an attachment leg 7, preferably single, carrying at least one vibrating blade 8 which the radiating element 4 comprises. FIG. 1B shows vibrating blades 8 connected by one or two attachment legs 7 to the middle part 5.

Figure 2A shows an embodiment of the invention where four radiating elements 4 are composed of four rectangular blades 8 fixed to the box 10 of the timepiece 1, each being linked by such an attachment leg 7, these blades 8 being substantially radiant and with substantially coplanar main vibrating surfaces 6. The radiators 4 are free to vibrate according to their first mode of vibration and create a radiant acoustic wave which propagates in the direction of the axis of the timepiece, in particular a watch 1.

One can, again, according to the invention, achieve at least one such radiating element 4 by a partial cutting of the middle part 5 (or of the bezel 11, or of another component of the case of the part of horology, in particular a watch) in the form of a vibrating blade 8 connected to the middle part 5 by a single end 9 of the vibrating blade 8, as can be seen in FIG. 1A.

In a particular embodiment, at least one such radiating element 4 is produced by a partial cutout of the bezel 11, in the form of a vibrating blade 8 connected to the bezel 11 by a single end 9 of the vibrating blade 8 .

In a particular embodiment, at least one such radiating element 4 is produced by a partial cutout of the bottom 12, in the form of a vibrating blade 8 connected to the bottom 12 by a single end 9 of the vibrating blade 8.

The invention also relates to a timepiece 1, in particular a striking watch or / and a musical box, which comprises a casing 3, a movement 17 and at least one vibration generator 2 arranged to vibrate at its own frequencies. in a range of 1 kHz to 6 kHz, this vibration generator 2 comprising in particular timbres or blades of a keyboard. This covering 3 carries at least one vibration generator 2.

According to the invention, the covering 3 comprises at least one radiating element 4, which comprises in particular a vibrating blade 8, which vibrates at a fundamental natural frequency tuned with at least one of the natural frequencies of the at least one generator vibration 2.

The covering 3 preferably comprises a case 10 containing at least one middle part 5, and at least one such radiating element 4 is secured to the middle part 5 or to the case 10.

In particular variants, the cover 3 comprises at least one such radiating element 4 outside the caseband 5, or inside the box 10.

In different variants, which can be combined with each other, and visible in Figures 1A, 1B, 2A, 2B and 2C: at least one radiating element 4 is arranged on the outside of the middle part 5; at least one radiating element 4 is arranged on the outside of a bezel 11 carried by the middle part 5; at least one radiating element 4 is arranged on the outside of a base 12 which the box 10 comprises; at least one radiating element 4 is arranged on one or two horns 13 which the box 10 comprises; at least one radiating element 4 is arranged on a plate 14 that comprises the movement 17 of the timepiece 1, this radiating element 4 comprising a connecting component 15 passing through the case 10 of the timepiece 1. at least one radiating element 4 is arranged which constitutes a single piece with its element for fixing to the timepiece 1.

In the embodiment of Figure 1B, at least one such radiating element 4 is connected to the middle part 5 or to the box 10 by an attachment leg 7, in particular single, carrying at least one vibrating blade 8 that has the radiating element 4.

In the embodiment of Figure 1A, at least one such radiating element 4 comprises at least one vibrating blade 8 cut from the middle part 5 to which the vibrating blade 8 is connected by a single end 9 of the vibrating blade 8.

Preferably, the covering 3 comprises a plurality of such radiating elements 4, of which at least part of these radiating elements 4 have different fundamental natural frequencies.

In particular, this timepiece 1 is a ringing watch or / and a music box. It comprises such a casing 3, or / and a movement 17, carrying at least one vibration generator 2, this casing 3 or / and this movement 17 comprising at least one radiating element 4 vibrating at a fundamental natural frequency tuned with the minus one of the natural frequencies of the at least one vibration generator 2.

To return to the radiating elements 4, preferably vibrating blades 8, in particular additional plates, illustrated here of non-limiting rectangular shape, are screwed or welded or driven or fixed by any process allowing the transmission of acoustic vibration, to one or more elements of the covering such as lugs 13, the bars, the caseband 5, the bezel 11, the back 12 of the case 10, or even the links of the bracelet. These additional plates vibrate and radiate at the frequencies of their own modes when the bell is triggered, or for a sound display, or simply permanently to ensure, selectively, either amplification (resonance) or filtering (anti-resonance) noise emitted by a mechanism in operation. These vibrating elements play the role of the radiating plates constituting the radiating elements 4.

According to a first variant embodiment, the radiating elements 4 are fixed on the movement 17 of the timepiece 1, for example on the plate 14 of this movement 17, instead of being fixed on the casing 3 In this case, the connections 7 are preferably components which pass through the casing 3 in front of openings made watertight by gaskets.

According to a second variant embodiment, the radiating elements 4 and their connecting elements 7 constitute one-piece parts. Advantageously, at least one radiating element 4 is thus produced with a structural or covering component, at the level of a pre-assembly, which facilitates the final assembly of the timepiece 1.

The shape of these radiating elements 4, the fixing conditions and the materials used define the natural frequencies of these elements which are tuned to the natural frequencies of the ringing system (bells or blades of a keyboard in particular) or of the mechanism. FIGS. 1A and 1B represent these radiating elements 4 fixed for example on the middle part 5. FIG. 1B illustrates in particular radiating elements 4 of different sizes, with different attachment conditions, by one or more attachment legs 7, which naturally modifies their fundamental natural frequencies.

FIG. 2A shows a second embodiment of the invention.

Figures 2B and 2C illustrate two variants, the first with radiating elements 4 only external to the box, the second with radiating elements 4 external and internal to the box.

According to a third embodiment not illustrated, at least one radiating element 4 consists of a plate 8 whose shape is close to that of a crown or a spherical cap and of which the connecting element 7 is fixed in the center of this plate 8.

The radiating elements can be made of gold, or of another precious metal, such as platinum or platinoids, or of an alloy of one or more of these precious metals. Alternatively, they can be made of steel. Alternatively, they can be made of titanium or a titanium alloy. Alternatively, they can be made of silicon or silicon dioxide, or even polycrystalline diamond. Alternatively, they can be made of metallic glass, or of an at least partially amorphous alloy. Alternatively, they can be made of ceramic.

Advantageously, the radiating elements 4 are made in the form of a vibrating blade 8 comprising a plate 16 inscribed in a parallelepiped, the largest dimension of which is greater than or equal to 4 mm, the smallest dimension of which is between 0.05 mm and 2 mm, and the third dimension of which is greater than or equal to 2 mm.

Advantageously, a radiating element 4 comprises a vibrating blade 8 itself comprising at least one plate whose radii of curvature are greater than 0.5 mm.

The radiating elements 4 not only make it possible to increase the acoustic intensity of the timepiece, in particular a watch 1, but also to optimize the directivity of the sound. Indeed, the vibrating surface, or at least a main vibrating surface 6, can be oriented so that the radiation is maximum in a particular desired direction. In an embodiment comprising several radiating elements 4, it is also possible to define a specific directivity for each note produced, thus generating a stereophonic effect.

A vibro-acoustic model has been developed, within the framework of the invention, to correctly size the radiating elements 4 and to predict the acoustic gain provided by these vibrating elements.

In the embodiment of Figure 3, the radiating elements 4 have been optimized so that their first eigen modes have a frequency of 1350 Hz. A harmonic excitation sweeping the frequencies between 1000 Hz and 3200 Hz is applied to the cover 3.

This figure 3 shows the acoustic level of a casing 3 composed of a middle part 5 and a bezel 11 with glass, respectively without radiating elements (in solid line) and with radiating elements 4 according to the invention ( in broken line) according to the frequency of the excitation which is imposed on it. In the configuration "without radiators", the sound level increases at a frequency greater than 3 kHz which corresponds to a frequency of one of the natural modes of the casing 3.

When the radiating elements 4 are added to the casing 3, the sound level increases considerably at the frequency of the first natural mode of the radiator (at 1350 Hz). The gain is 10 to 15 dB. The coupling between the radiating elements 4 and the casing 3 appears at 1900 Hz, which also generates an improvement in the acoustic level. The coupling between the radiating elements 4 and the vibration modes of the casing 3 also introduces two anti-resonances at 1450 Hz and 2150 Hz, which also makes it possible to reduce the sound emission in the rest of the band compared to the case without radiators, thus filtering the parasitic noises produced by the mechanism.

In Figure 4, the sound level of a cabinet 3 with radiating elements 4 (in broken line) having a first clean mode close to 2200 Hz is compared to that of the same cabinet 3 without radiators (in solid line) . Again, the radiating elements 4 provide a strong acoustic improvement at the frequency of their first modes.

Following these results, the radiating elements 4 can be sized for each of the frequencies generated by the sound system, ringing, alarm clock, music, or the like. The sound produced by the timepiece, in particular a watch, can be optimized over a wide frequency band. A specific dimensioning of the radiators also makes it possible to filter parasitic noise from the mechanism.

In short, the invention improves the acoustic performance, not only compared to the patent applications of the same depositor Montres Breguet SA cited above, but also compared to the document FR1136675A Junghans also cited above, which together represent the most efficient mechanisms up to the invention: the achievements of the prior art have always come up against the difficulty of making a system (for example a clock) radiate at several independent frequencies in the 1kHz-6kHz band, other than by a single resonance. Thus, in FR1136675A, the frequency radiating from the membrane coincides with the only frequency radiating from the equipment, and therefore from the casing.

The present invention introduces the solution of radiating elements, which are not membranes, which on the contrary makes it possible to add one or more additional radiation frequencies to the natural frequency of radiation of the system covering: the result , as shown in Figures 3 and 4, is that the frequencies of the radiating elements 4 are added to the frequency of the cover 3, without destroying or replacing it, while in the prior art only one resonance is visible, that of the system with the membrane.

The characteristics of the invention constitute a novelty compared to the prior art which was only intended to improve the radiation of the elements which constitute the covering, such as the bezel-glass assembly, the middle part or the back, or to directly radiate the sound-generating element.

In the case of the invention, the generation element is not necessarily radiating, and even advantageously remains non-radiating and physically distinct from the radiating element, which makes it possible to ensure the low rate of d 'damping and the frequency purity of the vibration (and therefore ultimately of the sound), while the radiating element is transferred to the casing but is not part of the components which constitute the casing, which in particular guarantee the tightness of the casing. timepiece 1 especially in the case of a watch.

The implementation of the invention is easy, of moderate cost, and provides many advantages over the prior art: improvement of the acoustic level of the sound radiated by a timepiece, in particular a watch in the frequency band between 1 kHz and 6 kHz; - possibility of individual and specific optimization of the radiating elements 4 to improve the overall acoustic level (in particular according to the melody or the tuning of the timbre); - this system does not impose any design constraints on the casing: • the seal is not impaired because all the seals can be preserved, which is essential on any timepiece, in particular a waterproof watch; • in certain embodiments, the impact resistance and the internal size do not have to be modified; possibility of optimizing the directivity of the sound produced by the timepiece, in particular a watch 1, selectively in frequency, and therefore of obtaining stereophonic effects; - possibility of very economical production of the radiating elements 4 by electroforming; - Possibility of tuning the natural frequency of each radiating element 4 to that of a blade of a keyboard or to that of a gong; - preservation of the clarity of the sound emitted by the mechanism.

Claims (31)

1. Method for improving the acoustic level of a musical or striking timepiece (1) comprising at least one vibration generator (2) arranged to vibrate at its own frequencies in a range of 1 kHz to 6 kHz, this at least one vibration generator (2) comprising in particular gongs or blades of a keyboard, characterized in that a casing (3) or / and a movement (17) included in said timepiece ( 1) by integrating or adding at least one radiating element (4) arranged to vibrate and radiate at its fundamental natural frequency tuned with one of said natural frequencies of said at least one vibration generator (2), with a frequency difference between said two natural frequencies less than or equal to the ratio between the fundamental natural frequency of said at least one radiating element (4) and the inverse of the quality factor of said at least one radiating element (4), or with a difference frequency between said two natural frequencies inf Erieur or equal to 100 Hz. 2. Method according to claim 1, characterized in that said fundamental natural frequency is tuned with said natural frequency of said at least one generator, with a frequency difference less than or equal to the lowest value between, on the one hand the ratio between the fundamental natural frequency of said at least one radiating element (4) and the inverse of the quality factor of said at least one radiating element (4), and on the other hand the value of 100 Hz. 3. Method according to claim 1 or 2, characterized in that, to determine the number of radiating elements (4), the following steps are carried out: - determining the number N of vibration modes of said at least one vibration generator (2); - equipping said timepiece (1) with a number N of radiating elements (4), each fixed to the outside of the case of said timepiece (1). 4. Method according to claim 3, characterized in that it is verified that each radiating element (4) has the sole function of vibrating and radiating. 5. Method according to claim 4, characterized in that each radiating element (4) is oriented in a particular listening direction for which said timepiece (1) is designed. 6. Method according to claim 4 or 5, characterized in that each radiating element (4) is optimized so that its fundamental natural frequency is tuned substantially equal to one of said natural frequencies of said at least one vibration generator (2). , with a frequency difference between said two natural frequencies less than or equal to the ratio between the fundamental natural frequency of said radiating element (4) and the inverse of the quality factor of said radiating element (4), or with a frequency difference between said two natural frequencies less than or equal to 100 Hz. 7. Method according to claim 4, characterized in that it is verified that each radiating element (4) is distinct from said at least one vibration generator (2). 8. Method according to one of claims 1 to 7, characterized in that modifies said covering (3) or said movement (17) by integrating or adding a plurality of radiating elements (4). . 9. Method according to claim 8, characterized in that at least part of the radiating elements (4) with different fundamental natural frequencies is chosen. 10. Method according to one of claims 1 to 9, characterized in that at least one said radiating element (4) is produced with a main vibrating surface (6) oriented in a preferred direction to promote sound diffusion towards the user. 11. Method according to one of claims 1 to 10, characterized in that at least one said radiating element (4) is secured with a middle part (5) that comprises said covering (3), or with a box (10). that comprises said casing (3), or with a bezel (11) which carries said middle part (5), or with a plate (14) which comprises said movement (17) of said timepiece (1). 12. The method of claim 11, characterized in that said at least one radiating element (4) outside of said middle part (5), 13. The method of claim 11 or 12, characterized in that arranges said at least one radiating element (4) outside the bezel (11) that carries said middle part (5). 14. Method according to one of claims 11 to 13, characterized in that said at least one radiating element (4) outside of a bottom (12) that comprises said box (10). 15. Method according to one of claims 11 to 14, characterized in that said at least one radiating element (4) is arranged on one or two horns (13) that comprises said box (10). 16. Method according to one of claims 11 to 15, characterized in that said at least one radiating element (4) is arranged on the plate (14) that comprises said movement (17) of said timepiece (1). ), said radiating element (4) comprising a connecting component (15) passing through said case (10) of said timepiece (1). 17. Method according to one of claims 1 to 16, characterized in that one arranges at least one said radiating element (4) which constitutes a single piece with its element for fixing to said timepiece (1). 18. Method according to one of claims 11 to 17, characterized in that said at least one radiating element (4) is connected to said middle part (5) or to said case (10) or to said movement (17) by a single attachment leg (7) carrying at least one vibrating blade (8) that comprises said at least one radiating element (4). 19. The method of claim 11, characterized in that said at least one radiating element (4) by a partial cutting of said middle part (5), in the form of a vibrating blade (8) connected to said middle part. (5) by a single end (9) of said vibrating blade (8). 20. The method of claim 13, characterized in that said at least one radiating element (4) is produced by a partial cutout of said bezel (11), in the form of a vibrating blade (8) connected to said bezel. by a single end (9) of said vibrating blade (8). 21. The method of claim 14, characterized in that said at least one radiating element (4) is produced by a partial cutout of said base (12), in the form of a vibrating blade (8) connected to said base by a single end (9) of said vibrating blade (8). 22. Method according to one of claims 1 to 21, characterized in that said at least one radiating element (4) is produced in the form of a vibrating blade (8) comprising a plate (16) inscribed in a parallelepiped. the largest dimension of which is greater than or equal to 4 mm, the smallest dimension of which is between 0.05 mm and 2 mm, and the third dimension of which is greater than or equal to 2 mm. 23. Method according to one of claims 1 to 22, characterized in that at least one said radiating element (4) comprises a vibrating blade (8) comprising a plate (16) whose radii of curvature are greater than 0.5 mm. . 24. Method according to one of claims 1 to 23, characterized in that said at least one radiating element (4) is produced in gold, or in precious metal, or in silicon, or in ceramic, or in metallic glass, or steel, or titanium. 25. Musical or striking timepiece (1) obtained by a method of improving the acoustic level according to one of claims 1 to 24, in particular a striking or / and musical box watch, characterized in that said piece watchmaking (1) comprises a casing (3), a movement (17) and at least one vibration generator (2) arranged to vibrate at its own frequencies in a range of 1 kHz to 6 kHz, this at least one generator vibrations (2) comprising in particular gongs or blades of a keyboard, said casing (3) or / and said movement (17) comprising at least one radiating element (4) arranged to vibrate and radiate at its tuned fundamental natural frequency with one of said natural frequencies of said at least one vibration generator (2). 26. Timepiece (1) according to claim 25, characterized in that the casing (3) comprises a box (10) containing at least one middle part (5), and in that at least one said radiating element ( 4) is integral with said caseband (5) or with said case (10). 27. Timepiece (1) according to claim 26, characterized in that it comprises said at least one radiating element (4) outside said middle part (5), or inside said case ( 10). 28. Timepiece (1) according to claim 26 or 27, characterized in that said at least one radiating element (4) is connected to said middle part (5) or to said case (10) by an attachment leg. (7) single carrier of at least one vibrating blade (8) that comprises said at least one radiating element (4). 29. Timepiece (1) according to one of claims 26 to 28, characterized in that said at least one radiating element (4) comprises at least one vibrating blade (8) cut from said middle part (5) to which said at least one vibrating blade (8) is connected by a single end (9) of said at least one vibrating blade (8). 30. Timepiece (1) according to one of claims 25 to 29, characterized in that it comprises a plurality of radiating elements (4) of which at least part of the radiating elements (4) have natural frequencies. different fundamentals between them. 31. Timepiece (1) according to claim 25, characterized in that the movement (17) carries at least one vibration generator (2) vibrating at its natural frequencies, said movement (17) comprising at least one said radiating element (4) fixed on the plate (14) of this movement (17).