Resonant member for a chiming mechanism of a watch or a music box

Abstract

The resonating element (1) for a striking mechanism of a watch or music box comprises at least one resonating part (2), such as one or more gongs, arranged to vibrate and resonate upon activation, and a mounting part (3). The resonating part (2) and / or the mounting part (3) is made of a tungsten, tantalum, rhodium, or hafnium alloy containing more than 51% tungsten, tantalum, rhodium, or hafnium.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a resonating element comprising at least one resonant part, such as one or more gongs, or a keypad for a striking mechanism in a watch or music box. The gong(s) or each keypad must be made of a special material to accommodate the available space within the watch case while ensuring the generation of a rich sound when the gong(s) are struck or one or more keys are activated.

[0002] The invention also relates to a method for making a resonant organ. STATE OF THE ART

[0003] In watchmaking, a watch movement can be equipped with a striking mechanism, such as a minute repeater. For this purpose, the resonating element used includes a gong, which is a circular metal wire, for example, made of steel. This metal wire is generally arranged around the movement inside the watch case. The gong is attached, for example by welding or brazing, to a gong holder, which is itself fixed to the mainplate or the case middle. The vibration of the gong is produced by the impact, usually near the gong holder, of at least one hammer. This vibration is composed of several natural or partial frequencies, the number and intensity of which, particularly in the audible range between 1 kHz and 20 kHz, depend on the geometry of the gong and the physical properties of the material used.

[0004] The gong, in the form of a metal wire, can also be made of gold, as defined in patent EP 2 107 436 B1, to produce a wide range of tonal variations in the sound generated by the striking of the hammer. While a gold gong produces a richer sound when the striking mechanism's hammer is struck, it can deform excessively due to its own weight. Since the space available within the watch case for the gong can be limited, it can easily come into unwanted contact with neighboring parts. This is a disadvantage of such a gong made of gold or any metal with high density and a low modulus of elasticity.

[0005] Under these conditions, noise isolators could be placed around the gong(s) of the mechanism to prevent such unintentional shocks or chimes. However, space is very limited in traditional watches to place noise isolators between the gong(s) while still ensuring a rich sound when the gong(s) are struck at the desired moments.

[0006] Of course, a clock movement can also include a striking mechanism to generate music when activated. To achieve this, the mechanism may incorporate a resonating element in the form of a musical keyboard. The metal keys can be activated by pins arranged on a rotating disc or cylinder when the striking mechanism is activated. The same drawbacks as with an arrangement of one or more gongs made of the aforementioned material can be observed with a metal key keyboard.

[0007] It should also be noted that in a traditional musical or chiming watch, the acoustic efficiency, based on the complex vibro-acoustic transduction of the case components, is low. To improve and increase the acoustic level of a sound or note, the material, geometry, and boundary conditions of the case components must be taken into account. The configurations of the case components are also dependent on the watch's aesthetics and operational constraints, which can limit the possibilities for adaptation.

[0008] Patent application CH 708 963 A2 describes a musical keyboard for a chiming watch. The keyboard blades have a Young's modulus between 70 and 120 GPa and a density greater than 14 g / cm³. The blades can be made of tungsten.

[0009] Document EP2207069 A2 discloses a watch with a resonating organ featuring four gongs. SUMMARY OF THE INVENTION

[0010] The invention therefore aims to overcome the drawbacks of the prior art by providing a resonating organ, comprising one or more gongs or a blade keyboard for a striking mechanism of a watch or music box, with less deformation due to its own weight and capable of generating a rich, warm and loud sound once activated in a small space of the watch or music box.

[0011] For this purpose, the invention relates to a resonating organ, which includes the characteristics defined in independent claim 1.

[0012] Specific embodiments of the resonating organ are defined in dependent claims 2 to 4.

[0013] One advantage of the resonating organ lies in the fact that it is made of a tungsten, tantalum, rhodium, or hafnium alloy containing more than 51% tungsten, tantalum, rhodium, or hafnium by weight. Preferably, the alloy may contain more than 75% tungsten, tantalum, rhodium, or hafnium by weight. Furthermore, it is preferable to choose such an alloy with an E / ρ ratio of Young's modulus E to density ρ that approaches that of gold. The E / ρ ratio should, for example, be less than 28 x 10⁶ (m / s)². This allows for the generation, once activated, of a loud and rich sound with a large number of partials in the audible range from at least 1 kHz to 10 kHz.

[0014] Advantageously, the resonating organ can consist of a resonating part connected in a single unit to a mounting part. The resonating part can consist of one or more gongs, and the mounting part can be defined as a gong holder connecting one or more gongs, or one gong holder per gong.

[0015] Advantageously, the resonating organ, which comprises one or more gongs, is designed to minimize deformation due to its own weight once mounted in a watch case, and with a reduced space for positioning the gong(s). The gong(s) can also be made of tungsten, tantalum, rhodium, or hafnium alloy with a hardness greater than 250 HV, and preferably greater than 300 HV.

[0016] Advantageously, the resonating organ can be a musical keyboard made up of several bars connected to a single base in a single piece. Each bar or group of bars can be designed to generate a specific note when activated.

[0017] To that end, the invention also relates to a method for making a resonant organ as defined in independent claims 5 and 6. BRIEF DESCRIPTION OF THE FIGURES

[0018] The purposes, advantages, and characteristics of a resonating organ, comprising one or more chimes or a key keyboard for a striking mechanism in a watch or music box, will become clearer in the following description, particularly with regard to the drawings on which: there figure 1 represents a top view of a resonating organ in the form of a bell attached to a fixing part of a striking mechanism, in particular of a watch according to the invention, the figures 2a and 2brepresent side and top views of a stamp attached to a fixing part as shown in figure 1 with a distortion of the timbre due to its weight, the figure 3 represents a partial cross-sectional view of part of a striking or musical watch having a resonating organ with two gongs for a minute repeater, and the figure 4 represents a partial cross-sectional view of part of a chiming or musical watch having a four-bell resonating organ for a chime. DETAILED DESCRIPTION OF THE INVENTION

[0019] In the following description, all the parts of a striking mechanism, which includes a resonating element of a striking or musical watch, that are well known in this technical field are only briefly described. The emphasis is primarily on the resonating element and its implementation for the striking mechanism within the watch case, or even within a music box.

[0020] There figure 1represents a resonating organ 1, which comprises a resonating part 2 and a mounting part 3. In this case, the resonating part 2 comprises a bell 2, and the mounting part 3 is a bell-shaped plate extending from one end of the bell 2. Generally, the other end of the bell 2 is free. The resonating part 2 and the mounting part 3 preferably form a single piece, i.e., a single block made of the same material. According to the invention, the material used is an alloy comprising at least 51% by weight of tungsten, tantalum, rhodium, or hafnium.

[0021] The mounting portion 3 may be the same thickness as the lug 2 and includes holes for attaching the lug 2, for example by means of screws, to a corresponding part of the watch case or movement plate. The mounting portion 3 may also be of a different shape and thickness or be made from a portion of the same material as the watch case.

[0022] The gong 2 of a watch striking mechanism may be arranged in the watch case, preferably beneath a watch dial, and in an embodiment partially surrounding a watch movement. In this configuration, it may be circular in shape with a diameter corresponding to the diameter of the watch crystal, and describing a portion of a circle at an angle between 150° and 250°, preferably between 185° and 220°. The gong 2 may have a circular cross-section or, preferably, a rectangular cross-section, as shown in the figures. Dimensional examples are described below, without limitation to these examples.

[0023] The gong 2, fixed by the mounting part 3 in the watch case, is generally part of a striking mechanism, which preferably also includes a hammer to strike the gong at predetermined times. A portion of the hammer's impact area (not shown) typically strikes the gong near its connection to the mounting part 3 to generate an acoustic resonance.

[0024] Depending on the material used to make the resonating element 1, significant deformation of the resonating part 2 may occur once the resonating element 1 is fixed in the watch case or music box. Once fixed, the resonating part 2 can flex, that is, deform under its own weight, even when the watch is at rest. In the case of a resonating part 2 consisting of one or more gongs, and because the space where the gong(s) are located is very small, any movement or shock to the watch can cause the gong(s) 2 to come into contact with a neighboring gong or a nearby watch component. This can lead to unwanted ringing of the gong(s) independently of their normal activation at specific times, which is undesirable.

[0025] THE figures 2a and 2bThese figures represent the deformation of a gong 2 of the resonating element 1. The resonating element 1 is fixed by means of the mounting part 3 to a support within the watch case. This support, not shown, could be, for example, a portion of the watch case itself or a support on a mounting plate of the watch movement. It could also be a support within a music box. Once mounted, the gong 2 of the resonating element 1 is generally positioned in a plane parallel to and directly below the watch dial. However, even when at rest on a table or in a case, the weight of the gong from its mounting causes it to flex, that is, to deform under its own weight.

[0026] In a resting position, the gong 2, describing a portion of a circle, deforms by a distance d (viewed vertically) from its mounting part 3 to its free end. Depending on the space available for the gong or set of gongs in the watch case, it is necessary that such a gong 2, with a diameter, for example, of approximately 35 to 40 mm on a portion of a circle between 185° and 220° (for the note G, for example), and with a thickness and width equal to or greater than 0.4 mm, preferably close to 0.5 mm, have a deformation distance d of less than 20% of its cross-section, i.e., 0.1 mm in the case of the present invention.

[0027] As stated above, according to the present invention, the resonating organ 1 with one or more gongs 2 is made of an alloy containing more than 51% by weight of tungsten, tantalum, rhodium, or hafnium, and having an E / ρ ratio less than 28 × 10⁶ (m / s)². Furthermore, it may also be provided that said tungsten, tantalum, rhodium, or hafnium alloy has a hardness of more than 250 HV. A list of materials is given below.

[0028] The table below summarizes the criteria, which correspond to 5N gold and alternative materials, which are composed in particular of at least 51% by weight of tungsten or tantalum or rhodium or hafnium: Gold 5N Alternative materials > 51% by weight of tungsten or tantalum or rhodium or hafnium Deformation of the timbre under its own weight (simulation) 0.223 mm < 0.1 mm E / Z ratio< 5.4·10 6< (m / s) 2< The smallest possible to get closer to the E / ρ ratio of gold HV Hardness 250-280 HV at least > 250 HV

[0029] For illustrative purposes only and not as a limitation, a gong 2 can be made that produces a G note when struck by a hammer of the striking mechanism. The gong 2 can be made of a tungsten alloy where the tungsten content is greater than 95% by weight. The Young's modulus E is 330 GPa, the density ρ is 18 g / cm³, and the hardness is approximately 310 HV. The gong has a diameter of approximately 35 to 40 mm and a circular arc with an angle of 198.83°, and the E / ρ ratio is 18.3 × 10⁶ (m / s)². In this case, the gong deforms due to its own weight by approximately 0.053 mm, which is less than the desired 0.1 mm.

[0030] We can also define the formula for the deformation of a fixed beam, which deforms under its own weight. This beam deformation formula can be used as an example to determine the deformation of a snare 2 of a more complex resonating organ 1. Thus, the formula for calculating the deflection of this type of system, for a rectangular beam cross-section, is as follows: fi = ρ ⋅ L 4 / 8 ⋅ E ⋅ l where L is the length of the beam, p is the weight of the beam per unit length, E is the Young's modulus, and I = b·h 3< / 12 for a rectangular section with b the width of the beam and h the height of the beam.

[0031] In our case, the second support (or supports) is curved. Calculating the deformation of the supports therefore involves extrapolating the formula initially adapted for the aforementioned fixed beam. This calculation for supports is thus much more complex and requires a finite element analysis.

[0032] The length of at least one 2-bell snare is related to the desired resonant frequency: fn = 1 / 2 π ⋅ β n ⋅ L 2 ⋅ b / L 2 ⋅ E / 12 ⋅ ρ 1 / 2 where ρ is the density of the material, β n ·L = ((2n - 1) / 2)·π for n>5, n being the mode number.

[0033] This equation is valid for vibration modes, which are in the plane of impact. The E / ρ ratio is specific to the material of the snare. The smaller this ratio, the more partials there are, and therefore the richer the sound. A rich sound is perceived as louder by the human ear. Therefore, when choosing the material for the snare, the E / ρ ratio should be as small as possible, and ideally as close as possible to that of gold.

[0034] It is also worth noting that switching to a material that deforms less than gold can also optimize the space inside the watch case. If the material deforms less, a reduction in the diameter of the watch case and the thickness of the gong(s) can also be achieved.

[0035] The alloy, containing more than 51% by weight of tungsten, tantalum, rhodium, or hafnium, may also contain one or more of the following elements: nickel (Ni), copper (Cu), iron (Fe), molybdenum (Mo), tantalum (Ta), hafnium (Hf), niobium (Nb), zirconium (Zr), and cobalt (Co). These alloying elements can, for example, enhance the mechanical properties and / or corrosion resistance of the alloy. These elements can also be selected based on their phase diagram with tungsten, tantalum, rhodium, or hafnium. Obtaining certain phases can be advantageous for machinability and / or acoustic properties.

[0036] The alloy may be designed to contain more than 75% by weight of tungsten, tantalum, rhodium, or hafnium. In a specific case, the alloy may contain more than 90% by weight of tungsten, while also including nickel and copper.

[0037] The Young's modulus can be between 280 and 400 GPa and the mass density can be greater than 15 g / cm³.

[0038] The resonating element 1, composed of several snare elements 2, 2', 2", 2", can be produced by milling, electrical discharge machining (EDM), laser machining, molding, casting, hot pressing, or another machining method suitable for this technical field. The snare element(s) 2, 2', 2", 2", can also be made from cast products, hot-pressed products, or products formed using hot or cold processes. This implies that the snare elements 2, 2', 2", 2", can be anisotropic or isotropic. These characteristics can influence the acoustic properties.

[0039] The resonant element 1 can undergo heat treatment to enhance its mechanical properties, corrosion resistance, and / or acoustic properties, for example. Furthermore, the resonant element 1 can benefit from a surface treatment that forms a layer on the surface of the alloy containing more than 51% by weight of tungsten, tantalum, rhodium, or hafnium, thereby improving corrosion resistance and / or surface hardness, for example. The thickness of this additional layer on the base element can range from 10 nm to 200 µm. This additional layer can also serve to protect the base element, particularly from corrosion.

[0040] There figure 3This represents a partial cross-sectional view of a striking or musical watch component, which includes a resonating organ 1 with two gongs 2, 2' for a minute repeater. The first gong 2, circular in shape for example, is positioned above the second gong 2', also circular in shape for example, but of a different length, so as to produce a different note than the first gong when activated.

[0041] The first gong 2 may be located just below a watch dial 4, while the second gong 2' is below the first gong and above an inner edge 5' of the watch case 5. A portion of a joint 6 connects the dial to the case 5. A reduced space 10 in the placement of the gongs 2, 2' is provided, but this does not guarantee that the gongs 2, 2' will not collide with each other or unintentionally come into contact with the edge of the vibration space 10. This depends on the material used to make them, such as an alloy with more than 51% by weight of tungsten, tantalum, rhodium, or hafnium.

[0042] Each stamp 2, 2' has a width I1 equal to or greater than 0.4 mm. The first stamp 2 is spaced from the dial 4 by a height h1 approximately equal to its cross-sectional area. The second stamp is spaced by a height h2 less than twice its cross-sectional area from the first stamp 2 without deformation. Finally, the second stamp is spaced by a height h3 approximately equal to its cross-sectional area from the lower, inner edge 5' of the case 5. The first and second stamps 2, 2' are spaced from the case 5 by a distance d1 equal to or less than twice their cross-sectional area.

[0043] There figure 4 represents a partial cross-sectional view of a part of a chiming or musical watch, which includes a resonating organ 1 with four gongs 2, 2', 2", 2"' for a chime according to the invention. The first and second gongs 2, 2' are arranged in the same way as in the embodiment of the figure 3A third 2" gong is mounted coaxially inward and in the same plane as the first 2" gong. A fourth 2' gong is mounted coaxially inward and in the same plane as the second 2' gong. Each gong is of a different length so that each produces a distinct note when activated. The space between the first and third 2' gongs, and between the second and fourth 2' gongs, is approximately twice the value of their cross-sectional area.

[0044] Of course, other dimensional values ​​of the gongs can be applied depending on the size of the watch equipped with the striking mechanism.

[0045] IlIt may be envisaged that two or more resonant parts 2 are connected to a single fixing part 3. In the case of a resonant organ 1 composed of snare drums 2, one or more snare drums 2 may be connected to the same fixing part 3, such as a snare drum holder 3, while other snare drums 2 may each be connected to their own different fixing part 3, such as their own snare drum holder 3.

[0046] Il It should also be noted that the resonating organ 1 is adapted with the choice of material in accordance with the material of the covering parts in order to have better sound transmission between the vibrating timbre(s) and the neighboring covering parts.

[0047] Everything that has been described for a resonant organ 1 with one or more timbres can be applied in the same way to a resonant organ 1 in the form of a blade keyboard to be able to play a melody once activated.

[0048] From the description just given, several variants of the resonating organ for a chiming mechanism of a watch or music box can be designed by a person skilled in the art without departing from the scope of the invention defined by the claims.

Claims

1. A resonant organ (1) for a striking mechanism of a watch or of a musical box, comprising at least one resonant part (2) arranged to vibrate and resonate once activated, in which at least the resonant part (2) is made of a tungsten or tantalum or rhodium or hafnium alloy with more than 51% by weight of tungsten or tantalum or rhodium or hafnium in the alloy, in which the resonant part (2) comprises at least four circular-shaped gongs (2, 2', 2", 2‴) with different lengths so as to each generate a different specific note once activated for a chime; a first gong (2) and a second gong (2') can be arranged one above the other in a watchcase; a third gong (2") and a fourth gong (2"') can be arranged one above the other in a watchcase; the third gong (2") is designed to be fitted coaxially with the first gong (2'), inwards and in the same plane as the first gong (2); and in which the fourth gong (2"') is designed to be fitted coaxially with the second gong (2'), inwards and in the same plane as the second gong (2').

2. The resonant organ (1) according to claim 1, characterised in that it comprises a fastening part (3) made in one piece with the resonant part (2, 2', 2", 2"') of each gong as a single piece.

3. The resonant organ (1) according to claim 1, characterised in that each of the four gongs (2, 2', 2", 2"') is connected at one end to a fastening part (3) and another end is free to move, and in that each gong is circular in shape so as to be arranged in a watchcase forming a portion of a circle with an angle between 150° and 250°, and preferably between 185° and 220°.

4. The resonant organ (1) according to claim 3, characterised in that each of the four gongs (2, 2', 2", 2"') has a circular or rectangular cross-section with a thickness or width greater than or equal to 0.4 mm.

5. A method for producing a resonant organ (1) according to any of claims 1 and 2, the resonant organ being characterised in that the resonant part (2) comprises at least four circular gongs (2, 2', 2", 2‴) with different lengths so as to each generate a different specific note once activated for a chime, in that a first gong (2) and a second gong (2') can be arranged one above the other in a watchcase, in that a third gong (2") and a fourth gong (2"') can be arranged one above the other in a watchcase, in that the third gong (2") is designed to be fitted coaxially inwards and in the same plane as the first gong (2), and in that the fourth gong (2"') is designed to be fitted coaxially inwards and in the same plane as the second gong (2'), the method comprising a production step in which the resonant organ (1) is produced from a tungsten or tantalum or rhodium or hafnium alloy with more than 51% by weight of tungsten or tantalum or rhodium or hafnium, and a heat-treatment step in which the resulting resonant organ is heat-treated to enhance its mechanical properties, corrosion resistance and / or acoustic properties.

6. The method for producing a resonant organ (1) according to any of claims 1 and 2, the resonant organ being characterised in that the resonant part (2) comprises at least four circular gongs (2, 2', 2", 2‴) with different lengths so as to each generate a different specific note once activated for a chime, in that a first gong (2) and a second gong (2') can be arranged one above the other in a watchcase, in that a third gong (2") and a fourth gong (2‴) can be arranged one above the other in a watchcase, in that the third gong (2") is designed to be fitted coaxially with the first gong (2), inwards and in the same plane as the first gong (2), and in that the fourth gong (2"') is designed to be fitted coaxially with the second gong (2'), inwards and in the same plane as the second gong (2'), the method comprising a production step in which the resonant organ (1) is produced from a tungsten or tantalum or rhodium or hafnium alloy with more than 51% by weight of tungsten or tantalum or rhodium or hafnium, and a surface-treatment step forming an additional layer on the surface of the alloy to improve its corrosion resistance and / or surface hardness.

Images