EP2881805A1 - Musical keyboard of a watch or music box with optimised dispersion - Google Patents

Abstract

Optimized radiation watch or music box keyboard (1) having a plurality of cantilever blades (2).

Said blades (2) are each in a Young's modulus material E and of density p satisfying the inequality $\sqrt{\frac{\mathrm{E}}{{\mathrm{\rho }}^{\mathrm{3}}}}<\mathrm{0.25}\mathrm{m}/\mathrm{s}$

Said blades (2) are each in a Young's modulus material between 70 GPa and 120 GPa, and with a density greater than 14.

Clock mechanism (50) of a watch (100) or of a music box (200) comprising at least one such keyboard (1).

Timepiece (500), constituted by a watch (100) or a music box (200) comprising at least one such striking mechanism (50) and / or at least one such keyboard (1).

Description

Field of the invention

The invention relates to a watch ring or optimized radiation music box with a plurality of cantilever blades.

The invention also relates to a watch ring mechanism or music box comprising at least one such keyboard.

The invention also relates to a timepiece constituted by a watch or a music box comprising at least one such mechanism and / or at least one such keyboard.

The invention relates to the field of timepieces comprising a striking mechanism, including watches and music boxes.

Background of the invention

The striking mechanism of musical watches or music boxes is generally constituted by a keyboard and an activation system of the blades of this keyboard. The activation system may be a rotating cylinder or a rotating disk, or the like.

So far, the keyboard material has been chosen mainly on the basis of manufacturability criteria and resistance to wear and fatigue. The reason is that the keyboard blades are subjected to repeated elastic forces and the friction between the surface of the blades and the activation pins can induce either the abrasion or the matting of the surfaces. At the same time, until now, manufacturers of bell watches or music boxes have always tried to increase as much as possible the activation energy of the blades, which requires very considerable elastic forces, especially for the shortest blades, corresponding to the most acute sounds.

Summary of the invention

The present invention proposes the introduction of an optimized ring keypad, in a material having particular elastic properties, specific to ensure optimal radiation of the sound emitted by the cladding, and with a specific geometry to store the maximum energy in the smallest space.

The energetic study of a striking keypad, undertaken to solve this problem of optimization of the radiation, highlights the fact that the activation energy must exceed a defined threshold (approximately 20 microwatt), slightly dependent on the of the watch, to allow effective radiation and to obtain a strong improvement of the sound level (improvement of more than 10 dB around this threshold), but that there is not a consequent advantage to increase further the energy of activation beyond this threshold. Indeed, beyond this threshold, the improvement becomes linear, which means that it is necessary to double the available energy to increase by only 3 dB the level of the sound produced.

At the same time, the coating and curing techniques of the materials nowadays make it possible to reduce the risk of wear and fatigue of the watch components, and make it possible to use relatively flexible materials for the ringer keyboard function.

This makes it possible to choose the keyboard material on the basis of an energy criterion (all the blades must have an activation energy greater than 20 microwatts) and a criterion of size of the component.

The invention thus comes to propose an unusual solution, and quite contrary to the uses of the profession, by defining an optimized ringtone having both a modulus of elasticity lower than traditionally used steel keyboards and a higher density. high: the main example of this family of keyboards optimized according to the invention is the keyboard in gold or gold alloy.

Thanks to the use of this material, or other materials fulfilling the same physical conditions, it is possible to standardize the acoustic level of the notes played, while remaining in a reduced space: to obtain this optimal system it is necessary to use a well defined and adapted geometry, detailed in the following description.

For this purpose, the invention relates to a watch ring or optimized radiation music box comprising a plurality of blades in cantilever, characterized in that said blades are each in a Young modulus material E and density ρ satisfying the inequality $\sqrt{\frac{\mathrm{E}}{{\mathrm{\rho }}^{}}}$$\sqrt{\frac{{\mathrm{}}^{\mathrm{3}}}{}}<\mathrm{0.25}\frac{\mathrm{m}}{\mathrm{s}}\mathrm{.}$

According to one characteristic of the invention, said blades are each in a Young's modulus material between 70 GPa and 120 GPa.

According to one characteristic of the invention, said blades are each of density greater than 14.

The invention also relates to a watch ring mechanism or music box comprising at least one such keyboard.

The invention also relates to a timepiece constituted by a watch or a music box comprising at least one such mechanism and / or at least one such keyboard.

Brief description of the drawings

• la figure 1 représente, de façon schématisée, la répartition de l'énergie d'activation (en microwatt) d'une lame ayant un mode fondamental de flexion à 800 Hz, pour un clavier en or 750 selon l'invention (E = 110 GPa, ρ = 15100 kg/m³), en fonction de la longueur de la lame en abcisse, et de la levée de cette lame en ordonnée, pour une largeur de la lame de 0.4 mm ;
• la figure 2 représente, de façon schématisée, pour un clavier de l'art antérieur en acier, un diagramme, avec en abcisse la longueur de la lame, et en ordonnée l'encombrement vertical total de cette lame, c'est-à-dire le total de sa hauteur, et du double de son débattement appelé levée, cette levée étant évaluée de façon à obtenir une énergie d'activation de 20 microwatt, et ce diagramme représentant la réponse de ce clavier à certaines fréquences (en partie gauche pour une lame à 4000 Hz et en partie droite pour une lame à 800 Hz), chaque courbe en trait plein correspondant à la réponse avec l'encombrement vertical total, et chaque courbe en trait interrompu correspondant à la seule levée, et où l'encombrement maximal en longueur de lame et encombrement vertical total, caractéristique des limites de fonctionnement, est représenté par la région grisée ;
• la figure 3 représente, de façon analogue à la figure 2, le diagramme correspondant à un clavier selon l'invention en un premier alliage d'or 750 avec un module d'Young de 110 GPa et une densité de 15.1 ;
• la figure 4 représente, de façon analogue à la figure 2, le diagramme correspondant à un clavier selon l'invention en un deuxième alliage d'or avec un module d'Young de 120 GPa et une densité de 14.0 ;
• la figure 5 est une représentations schématisée et en perspective d'un clavier selon l'invention..

Other features and advantages of the invention will appear on reading the detailed description which follows, with reference to the appended drawings, in which:

• the figure 1 represents, schematically, the distribution of the activation energy (in microwatt) of a blade having a fundamental mode of bending at 800 Hz, for a 750 gold keyboard according to the invention (E = 110 GPa, ρ = 15100 kg / m ³ ), depending on the length of the blade in abscissa, and the lifting of this blade in the ordinate, for a width of the blade of 0.4 mm;
• the figure 2 schematically represents, for a keypad of the prior art steel, a diagram, with abscissa the length of the blade, and ordinate the total vertical space of this blade, that is to say the total of its height, and twice its deflection called lifting, this lifting being evaluated so as to obtain an activation energy of 20 microwatts, and this diagram representing the response of this keyboard to certain frequencies (in left part for a blade to 4000 Hz and in the right for a blade at 800 Hz), each curve in solid line corresponding to the response with the total vertical space, and each curve in broken line corresponding to the only lifting, and where the maximum size in length of blade and total vertical space, characteristic of the operating limits, is represented by the shaded region;
• the figure 3 represents, in a similar way to figure 2 , the diagram corresponding to a keyboard according to the invention in a first 750 gold alloy with a Young's modulus of 110 GPa and a density of 15.1;
• the figure 4 represents, in a similar way to figure 2 the diagram corresponding to a keyboard according to the invention in a second gold alloy with a Young's modulus of 120 GPa and a density of 14.0;
• the figure 5 is a schematic and perspective representation of a keyboard according to the invention.

Detailed Description of the Preferred Embodiments

The invention relates to the field of timepieces comprising a striking mechanism, including watches and music boxes.

More particularly, the invention relates to a keyboard 1 watch ring 100 or music box 200, optimized radiation, comprising a plurality of blades 2 cantilevered.

Each of these blades 2 is sized to vibrate at a specific frequency. The entire keyboard 1 is designed to broadcast the sound in a particular frequency range of the audible range. More particularly and not exclusively, this range relates to the frequencies of 800 Hz to 4000 Hz, the conceptual reasoning explained below applying to all other limit values of this frequency range.

.Advantageously, according to the present invention, each blade 2 of the keyboard 1 is made of a material for which $\sqrt{\frac{\mathrm{<figure-callout\; id="3"\; label="E\; \rho "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">E\; </figure-callout>}}{{\mathrm{\rho }}^{}}}<\mathrm{0.25}\mathrm{m}/\mathrm{s}\mathrm{.}$

.

In a variant of the invention, these blades 2 are each in a Young's modulus M material between 70 GPa and 120 GPa.

In a variant of the invention, these blades 2 are each of density greater than 14, and especially between 14 and 22.

Note that here we call "density" the relative density with respect to water; thus, a density of value "λ" corresponds to a density of λ. 10 ³ kg / m ³ . The various shades of gold and common gold alloys, including the "750" gold at 18 carats, satisfy this criterion.

In a variant of the invention, at least one blade 2 is made of an alloy comprising gold.

In a variant of the invention, at least one blade 2 is made of "750" gold comprising at least 75% gold.

Other materials obey the required conditions, and may be envisaged for the manufacture of a keyboard according to the invention, used alone, or in combination with gold, or in combination with at least gold, or combination between them, or in combination between at least two of them.

• Tungstène
• Iridium
• Platine
• Palladium
• Argent
• Cuivre
• Bronze
• Certaines fontes
• Verre
• Cristal
• Béryllium
• Chrome
• Manganèse
• Molybdène
• « Invar ®», « Inconels®», « Hastalloys ®» et similaires
• Différents carbures
• Oxyde de zirconium
• Saphir,

ledit au moins un élément étant utilisé seul, ou en combinaison avec de l'or, ou en combinaison avec au moins de l'or, ou en combinaison avec un autre élément dudit groupe, ou en combinaison entre aux moins deux éléments dudit groupe.Thus, in a variant, the keyboard 1 comprises at least one element of the group consisting of:

• Tungsten
• Iridium
• Platinum
• Palladium
• Money
• Copper
• Bronze
• Some fonts
• Glass
• Crystal
• Beryllium
• Chromium
• Manganese
• Molybdenum
• "Invar ®", "Inconels®", "Hastalloys ®" and the like
• Different carbides
• Zirconium oxide
• Sapphire,

said at least one member being used alone, or in combination with gold, or in combination with at least one gold, or in combination with another member of said group, or in combination between at least two members of said group.

In a particular embodiment, as visible on the figure 5 , all the blades 2 that make up the keyboard 1 form a one-piece assembly with a table 3 by which is fixed the keyboard 1. In other variants not shown, we can build the keyboard 1 with blades 2 each obey the beaches of Young's modulus and density values according to the invention, and each embedded in a table 3 which itself obeys, preferably, these same ranges of value.

$$U=\frac{\mathit{Eb}{h}^3{\delta }^2}{8L^3}\mathrm{.}$$

In the present description, for purposes of simplification, each blade 2 is a solid parallelepipedic prism. In practice, the same reasoning is applicable to blades 2 of different shapes and sections, solid or hollow. In this particular example, for each specific M material, Young's modulus E and density ρ, the geometry of the blades 2 (defined by the minimum length, the maximum length, the height h and the width b of the blades) is appropriate. obtained mathematically using the two equations defining respectively the frequency and the bending energy of a keyboard blade (modeled as a thin beam embedded at one end): $$f=\frac{3515<figure-callout\; id="4"\; label="\; h"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\; </figure-callout>h}{4\pi {\mathrm{The}}^2}\sqrt{\frac{\mathrm{<figure-callout\; id="3"\; label="E"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">E</figure-callout>}}{3\rho }},$$

$$U=\frac{\mathit{<figure-callout\; id="3"\; label="Eb\; \; h"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">Eb\; </figure-callout>}{h}^{}{}^3{\mathrm{<figure-callout\; id="2"\; label="\delta "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\delta </figure-callout>}}^2}{8{\mathrm{The}}^3}\mathrm{.}$$

For a given material and frequency, the height h of the blade 2 is determined by its length L: $$h=\frac{4\mathit{\pi f}}{3515}\sqrt{\frac{3\rho }{E}}{\mathrm{The}}^2\mathrm{.}$$

By introducing the relation (3) in (2), it is possible to obtain the activation energy of each plate 2 (having the fundamental mode of bending f) as a function of its length L and its lifting δ (for a fixed width b):

The figure 1 illustrates the activation energy (in microwatt) of a blade having the fundamental mode of bending at 800 Hz for a 750 gold keyboard (E = 110 GPa, ρ = 15100 kg / m ³ ) as a function of the length L of the blade and its lifting δ, for a width of the blade b = 0.4 mm.

For a given material, frequency, blade width and activation energy, the arrow necessary to obtain the activation energy U = 20 microwatts, is determined by the length L of the blade: $${\delta }_{f,b,U}\left(\mathrm{The}\right)={\left(\frac{8\mathrm{<figure-callout\; id="1"\; label="U\; b"\; filenames="imgf0002.png"\; state="\{\{state\}\}">U\; </figure-callout>}}{b}\right)}^{1/2}{\left(\frac{3515}{4\mathit{\pi f}}\right)}^{3/2}{\left[\frac{\mathrm{<figure-callout\; id="3"\; label="E"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">E</figure-callout>}}{{\left(3\mathrm{<figure-callout\; id="3"\; label="\rho "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">\rho </figure-callout>}\right)}^3}\right]}^{1/4}{\mathrm{The}}^{-3/2}\mathrm{.}$$

If the maximum space requirement in z is determined by 2 δ + h < H _max and the maximum space requirement of the boards in the direction defined by their main axis is determined by L < L _max , equation (4) makes it possible to determine the optimal configuration uniquely.

For the digital application, a width of the blades b = 0.4 mm is used, and the typical extreme frequencies of a bell pad are considered: f _min = 800 Hz and f _max = 4000 Hz.

For a traditional steel keyboard with E = 185 GPa and density 8000 kg m ³ , equation (4) produces the curves represented by figure 2 , which illustrates the rise δ necessary to obtain an activation energy U = 20 microwatt, and the total vertical space requirement (defined by the sum of the height of the blade plus twice the lift: h + 2 δ) for a blade at 800 Hz and a blade at 4000 Hz, depending on the length of the blade. The maximum size in blade length and total vertical space is represented by the shaded area. The graphs C1 and C2 correspond to the frequency of 4000 Hz, respectively according to the total vertical space h + 2δ or according to the only lift δ, the graphs C3 and C4 are the pendants for the frequency of 800 Hz.

The figure 2 is a representation with a lift evaluated to obtain an activation energy of 20 microwatts, and shows the response of the keyboard at certain frequencies (on the left for a 4000 Hz blade and on the right for a 800 Hz blade) , each solid line curve corresponding to the response with the total vertical footprint, and each dashed curve corresponding to the only lift. The maximum overall length of the blade and the total vertical space, characteristic of the operating limits, are represented by the shaded area. Outside this region, the keyboard can not be integrated into a traditional wristwatch.

This figure 2 shows that, in the maximum admitted space (here L less than or equal to 12 mm, and maximum total space less than or equal to 1.5 mm), it is possible to activate the blade at 4000 Hz with the required energy (or upper): several blade geometries allow this result, for example a blade length L = 7.5 mm and height h = 0.25 mm activated with a lift δ = 0.2 mm, corresponding to the point A of the graph C1 in full line of the frequency 4000 Hz. On the other hand, it is impossible for this keyboard material to activate a blade at 800 Hz with the minimum energy required in the space allowance, since the curve C3 corresponding to the frequency 800 Hz with the maximum space requirement ( continuous curve) does not cross the area specific to congestion maximum of the keyboard, we see that a blade vibrating at 800 Hz and the same overall vertical space, that is to say according to point B of the graph C3, would require a length L of 17.4 mm.

In conclusion, in a traditional clock clutter, a steel keyboard does not allow to activate a blade with enough energy to obtain optimal acoustic radiation at all frequencies.

For a keyboard according to the invention, and especially in 750 gold, (with E = 110 GPa, and ρ = 15100 kg / m ³ ), equation (4) produces the curves represented in FIG. figure 3 which relates to a keyboard 1 according to the invention in 750 gold, with graphs similar to those of the figure 2 . It can be seen that, in this case, it is also possible to activate the blade at 800 Hz with sufficient energy while remaining within the desired size limits. It is therefore possible to activate all the blades with the same energy: in one of the possible configurations, corresponding to the point C of the graph C3, the 800 Hz blade has a length L = 12 mm and a height h = 0.3 mm being activated with a lift δ = 0.5 mm, ie a maximum overall size of 1.3 mm, whereas at point D of the graph C1 corresponding to the frequency of 4000 Hz, the corresponding blade 2 has a length L = 6 mm and a height h = 0.35 mm activated with a lift δ = 0.15 mm, ie a total maximum height of 0.65 mm.

A keyboard 1 with 15 blades 2, separated in pairs by a day of approximately 0.07 mm, having the physical characteristics defined according to the invention (E between 70 GPa and 120 GPa, and density between 14000 kg / m ³ and 20000 kg / m ³ ), always enables all blades 2 with an energy of more than 20 microwat in a footprint (active keyboard length x keyboard width x vertical height) limited to (12 mm x 7 mm x 1.5 mm ).

The figure 4 shows the definition curves of lift and vertical space for extreme (and therefore most critical) values of mechanical parameters (E = 120 GPa, ρ = 14000 kg / m ³ ). Even in this case, the optimal dimensioning of the keyboard is possible: the graph C3 crosses the grayed region, and at the point E of the graph C3, a blade of length L = 11.5 mm, and of maximum height clearance of 1.45 mm, is suitable for the frequency of 800 Hz, while there is no problem to ensure the radiation of the sound at the frequency of 4000 Hz.

pour une densité supérieure et/ou un module d'élasticité inférieur à celui de l'acier, il est donc possible de réduire, soit la levée δ requise, soit la longueur L des lames 2, soit les deux dimensions simultanément.In sum, the improvement over a steel keyboard is made possible by the fact that the frequency and the activation energy of the blade 2 according to the invention have a different functional dependence depending on the parameters and, in particular by the fact that at parity of activation energy: $${\mathrm{<figure-callout\; id="2"\; label="\delta "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\delta </figure-callout>}}^2{\mathrm{The}}^3~\sqrt{\frac{\mathrm{<figure-callout\; id="3"\; label="E\; \rho "\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">E\; </figure-callout>}}{{\rho }^{}}}\mathrm{.}$$

for a higher density and / or a modulus of elasticity lower than that of steel, it is therefore possible to reduce either the required lift δ or the length L of the blades 2, or both dimensions simultaneously.

In a variant of the invention, at least one blade 2 comprises a surface coating.

In a variant of the invention, at least one blade 2 has a hardened surface relative to its core.

• augmentation du niveau acoustique du son rayonné par une montre ou une boîte à musique dans la bande de fréquences comprises entre 1 kHz et 4 kHz ;
• amélioration de l'uniformité du niveau acoustique perçu au cours de la mélodie ;
• diminution de l'encombrement des composants de génération du son (clavier et disque).

The advantages provided by the implementation of the invention are substantial:

• increasing the sound level of the sound radiated by a watch or a music box in the frequency band between 1 kHz and 4 kHz;
• improvement of the uniformity of the acoustic level perceived during the melody;
• reduced clutter of sound generation components (keyboard and disk).

The invention also relates to a watch 50 ringing mechanism 100 or music box 200 comprising at least one such keyboard 1.

The invention also relates to a timepiece 500 constituted by a watch 100 or a music box 200 comprising at least one such mechanism 50 and / or at least one such keyboard 1.

Claims (13)

Keyboard (1) for an optimized radiation watch or music box ring comprising a plurality of cantilever blades (2), characterized in that said blades (2) are each in a Young's module material E and density ρ satisfying the inequality $\sqrt{\frac{\mathrm{E}}{{\mathrm{\rho }}^{\mathrm{3}}}}<\mathrm{0.25}\mathrm{m}/\mathrm{s}$

Keyboard (1) according to claim 1, characterized in that said blades (2) are each in a Young's modulus material between 70 GPa and 120 GPa. Keyboard (1) according to claim 1 or 2, characterized in that said blades (2) are each of density greater than 14. Keyboard (1) according to claim 3, characterized in that said blades (2) are each of density between 14 and 22. Keyboard (1) according to one of the preceding claims, characterized in that at least one of said blades (2) is made of an alloy comprising gold. Keyboard (1) according to one of the preceding claims, characterized in that at least one of said blades (2) is made of gold alloy "750" having at least 75% gold. Keyboard (1) according to one of the preceding claims, characterized in that all the blades (2) which compose it form a unitary assembly with a table (3) of said keyboard (1). Keyboard (1) according to one of the preceding claims, characterized in that at least one said blade (2) has a surface coating. Keyboard (1) according to one of the preceding claims, characterized in that at least one said blade (2) has a surface hardened relative to its core. Keyboard (1) according to one of the preceding claims characterized in that all blades (2) which compose it form a unitary assembly with a table (3) of said keyboard (1). Keyboard (1) according to one of the preceding claims, characterized in that it comprises at least one element from the group consisting of: • Tungsten • Iridium • Platinum • Palladium • Money • Copper • Bronze • Melting • Glass • Crystal • Beryllium • Chrome • Manganese • Molybdenum • "Invar ®" • "Inconel®" • "Hastalloy ®" • Carbide • Zirconium oxide • Sapphire, said at least one member being used alone, or in combination with gold, or in combination with at least one gold, or in combination with another member of said group, or in combination between at least two members of said group. Clock mechanism (50) watch (100) or music box (200) having at least one keyboard (1) according to one of the preceding claims. Timepiece (500), constituted by a watch (100) or a music box (200) comprising at least one striking mechanism (50) according to the preceding claim, and / or at least one keyboard (1) according to the one of claims 1 to 11.

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