CH715476A2 - Ringing or musical watch provided with at least one acoustic radiation membrane, and method of manufacturing the membrane. - Google Patents

Abstract

The watch (1) with striking or musical device according to the invention is provided with a membrane (2) of acoustic radiation made of metallic material or amorphous metal. The membrane is in the form of a wall loop of a certain thickness to be connected by a first border to a middle part (4) of a watch case and by a second border to a bezel (3) or directly to a crystal. watch (5). The bezel (3) linked to the crystal (5) is movable relative to the middle part (4) via the membrane (2) during the vibration of the membrane following a sound generated by a striking mechanism of the watch in the watch box. The membrane is configured with a wall of a determined thickness in an active zone (11) dependent on the mass of the telescope (3) linked to the glass (5) to have a frequency f 0 of a first mode of vibration, which is located at low frequency less than or equal to 4 kHz according to the equation f 0 = (1/2-π) · (k / m) 1/2 where k is the stiffness of the membrane, which depends on its thickness, and m is the mass of the telescope linked to the ice. The invention also relates to a method of manufacturing such a membrane (2) by electroforming.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a striking or musical watch provided with at least one acoustic radiation membrane. The watch notably includes a watch case with a back, a middle part and closed by a glass to view time information on a dial under the glass. The watch also includes in the watch case, a ringing mechanism to generate sound or music at predefined moments or voluntarily.

The invention also relates to a method of manufacturing an acoustic radiation membrane for a striking or musical watch.

STATE OF THE ART

It is known to provide a watch with a striking mechanism to generate sound or music. To do this, a timbre of the striking watch or a keyboard of the musical watch are placed in the watch case. Thus, the vibrations of the timbre or of the keyboard blades are transmitted to the various trim parts. These trim pieces are in particular the middle, the bezel, the crystal and the back of the watch case. These large cladding pieces begin to radiate sound in the air under the effect of transmitted vibrations. When a sound is produced either by a timbre struck by a hammer, or by one or more blades of the vibrating keyboard, these dressing pieces are capable of radiating the sound produced in the air.

However, in a musical watch or with a traditional striking mechanism, the acoustic efficiency, based on the complex vibro-acoustic transduction of the trim parts, is low. To improve and increase the acoustic level of a sound or a note, account must be taken of the material, the geometry and the boundary conditions of the covering parts. The configurations of the trim parts are also dependent on the aesthetics of the watch and the operating constraints, which can limit the possibilities of adaptation.

To be able to improve the vibro-acoustic efficiency of the striking mechanism, provision is made for one or more membranes in the watch case. The membranes are sized and configured so that the note (s) generated in the watch case are effectively radiated. The frequencies of the generated notes must be close to the natural modes of vibration of the membrane (s) so that they enter into resonance.

Patent application EP 0 028 429 A1 describes a watch with an electro-acoustic warning device. This device is intended to improve the sound performance and the quality of the sound. The watch glass is held in place by a ring supporting the middle. This support ring is an annular vibrating membrane. Between two edges of the membrane, a curved central area is provided. A central rod is fixed to the glass and activated by an excitation electromagnet for vibration. The membrane can be obtained by electroforming. The generation of a sound is obtained by the action of an electronic device excited by an alternating current, which does not bring the same quality of a sound generated by a ringing mechanism with mechanical action, which constitutes a disadvantage.

[0007] The patents EP 2 409 200 B1 and EP 2 738 625 B1 describe a watch case with a middle part closed on one side by a bezel and a crystal and on the other side by a back. The telescope and the glass are connected by an annular elastic metallic member in the form of a bellows with at least one annular fold of curvature between 90 ° and 180 ° to give the telescope and the glass connected to the bellows a freedom of movement perpendicular or parallel to a dial. However, these patents highlight the particular shape of the membrane while exploiting it to add a movement of freedom to the telescope and not as a radiating element for a ring. The natural frequency of oscillation of the assembly made up of the glass and the metallic member is higher than the frequency band of the transmitted signal so as not to have degradation or distortion of the sound, which does not allow effective radiating of the its generated. This therefore constitutes a drawback.

SUMMARY OF THE INVENTION

The invention therefore aims to overcome the drawbacks of the prior art by providing a striking or musical watch provided with at least one acoustic radiation membrane arranged to produce a rich sound with better acoustic radiation low frequency vibrations via the membrane linked to a crystal or a bezel linked to a crystal from the watch case.

To this end, the invention relates to a striking or musical watch cited above, which comprises the characteristics defined in independent claim 1.

Particular embodiments of the striking or musical watch are defined in dependent claims 2 to 13.

An advantage of the striking or musical watch lies in the fact that the membrane is configured in such a way that when it is excited by generation of a sound coming from at least one timbre or from a blade of a keyboard vibrating, there is a transmission of transverse waves. The thin membrane connects on one side a bezel attached to a crystal or directly a watch crystal, and on the other side a case case middle. Thus, the telescope with the glass or the glass only become mobile and vibrate at the same modes of vibration as the membrane in order to reach modes of vibration below 4 kHz, or at 1 kHz or even lower depending on the thickness of the membrane and / or its curvature also. The membrane acts as a spring in connection with the lens or with the lens which constitutes the mass. The frequency of the first mode of vibration depends on the square root of the stiffness on the mass. This first mode of vibration is of the piston type. Thus, the lower the stiffness of the membrane, the lower the frequency of the first vibration mode, which is sought.

Advantageously, the membrane can be manufactured by an electroforming process. It can be produced with a thickness of less than 80 μm, for example up to 37 μm, which makes it possible to lower the radiation frequency up to 500 Hz while allowing good acoustic radiation up to frequencies around 8 to 10 kHz. By working at such a low frequency, this makes it possible to obtain a warmer, stronger sound, because the more there are radiated modes and the more the human ear interprets this as a loud sound, and more distinguishable during the generation of a music.

The membrane can be made of a metallic material, such as 5N gold.

To this end, the invention also relates to a method of manufacturing at least one acoustic radiation membrane for a striking or musical watch, which includes the characteristics defined in independent claims 14 and 15.

A particular manufacturing step is defined in dependent claim 16.

BRIEF DESCRIPTION OF THE FIGURES

The aims, advantages and characteristics of a striking or musical watch provided with at least one acoustic radiation membrane and of the process for manufacturing the membrane will appear better in the following description, in particular with regard to the drawings in which: <tb> <SEP> FIG. 1 represents a partial view in cross section of a striking or musical watch having a membrane at the level of the crystal and the middle of the watch case according to a first embodiment of the 'invention, <tb> <SEP> FIGS. 2a to 2c represent several embodiments of the annular membrane, of which a cross section on one side is shown, according to the invention, <tb> <SEP> FIG. 3 represents a partial view in cross section of a striking or musical watch having a membrane at the level of the crystal and the middle of the watch case according to a second embodiment of the invention, and <tb> <SEP> FIGS. 4a to 4e schematically represent different stages of production of the membrane shown in cross section of the second embodiment according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, all the parts of a striking watch provided with an acoustic radiation membrane, which are well known in this technical field, are described only briefly. The main focus is on the arrangement of the membrane in the watch case and on its configuration to allow adequate acoustic radiation following the generation of a sound in the watch case.

FIG. 1 therefore represents a first embodiment of a mechanical striking or musical watch 1, which comprises at least one acoustic radiation membrane 2. This acoustic radiation membrane 2 is made of metallic material or amorphous metal and appears as a connecting piece in the form of a wall loop of a certain thickness. We can consider it as a spring membrane. This membrane 2 is designed to be connected by a first border 23 to a middle part 4 of a watch case, in particular on the upper part of the middle part 4, and by a second border 20 to a bezel 3 fixed to a watch glass. 5 by means of a seal 12. According to an alternative embodiment, the second edge 20 of the membrane 2 can also be directly connected to a watch crystal 5.

It should be noted that the first edge 23 of the membrane 2 can be fixed on the upper part of the middle part 4, in particular in an annular groove by means of an additional bezel 13. This additional bezel can be fixed by screwing on the upper part of the middle part 4 or by gluing or welding or soldering or by being driven out so that the lower portion of the complementary bezel 13 comes to fix the first edge in the annular groove of the middle part 4. The complementary bezel 13 can still serve as protection of the assembly comprising the telescope 3 linked to the glass 5 and to the membrane 2.

In Figure 1, the watch 1 ringing or musical also includes a striking mechanism represented only by a number of stamps 9 arranged in this configuration under the dial 6 of the watch. The striking mechanism is connected to a timepiece movement 14 arranged between the dial 6 and a base 7, which is fixed to a lower part of the middle part 4 with a seal 8. These stamps 9 spaced apart from one others can each be struck by a particular hammer not normally represented at specific times to each generate a different sound, which can also generate a melody. It can also be provided to have a keyboard with blades of different lengths, not shown, to be activated by a disc or cylinder with blades activation members in order to generate music according to the arrangement of the activation members.

The membrane 2, as shown in Figures 1 to 4, is of annular shape with an arcuate or curved part, which is directed towards the side of the watch glass 5 in an active area 11 of the membrane 2 in a direction Z perpendicular to the plane of the watch. The arched portion is a portion of a circle in a cross section as shown, which is extended by a straight portion, defining a frustoconical portion, up to connection with the first border 23. According to this first embodiment, the second border 20 of the membrane 2 is fixed by a fixing ring 10, which is driven for example on an outer cylindrical wall at the bottom of the telescope 3. An inner annular groove can be provided in the fixing ring for guiding an internal fold of the second edge 20 of the membrane 2. In addition, provision may be made to weld or braze this fixing ring 10 to the lower part of the bezel 3 in order to guarantee good sealing of the assembly of the membrane 2 to the bezel 3 .

The bezel 3 also includes an upper edge, where the watch glass 5 rests fixed by the gasket 12 to an inner upper wall of the bezel 3. A lower and inner edge of the bezel 3 is above the dial 6 without touching it to allow mobility of the telescope 3 with the glass 5 maintained by the membrane 2. A space between 70 and 100 μm is provided between the telescope 3 and the dial 6 or between the telescope 3 and the complementary bezel 13 to leave mobility to the membrane 2 and bezel assembly 3. Thus what is sought, the bezel 3 linked to the crystal 5 or the crystal 5 is movable relative to the middle part 4 via the membrane 2 during vibration of the membrane 2 following a sound generated by the striking mechanism of the watch in the watch case. The bezel 3 connected to the membrane 2 vibrates to the same modes of vibration as the membrane 2, which are significantly lower than the vibration modes of a conventional covering.

It should be noted that once the annular membrane is attached to the bezel 3 linked to the crystal 5 or to the crystal 5 alone, and to the middle part 4, the interior of the watch case ring or musical is waterproof while leaving freedom of movement to the telescope 3 linked to the membrane 2 or to the glass 5 linked to the membrane 2.

The membrane is configured with a wall of a determined thickness, dependent on the mass of the bezel 3 linked to the ice 5 or the ice 5 alone to have a low frequency f0du first mode of vibration. It is desired to have a low frequency less than or equal to 4 kHz and preferably less than or equal to 1 kHz. To do this, account is taken of the equation f0 = (1 / 2π) · (k / m) <1/2> where k is the stiffness of the membrane 2, which depends on its thickness, and m is the mass of the telescope 3 linked to the glass 5 or to the ice 5 alone. We can therefore lower the resonance frequency of the membrane 2 linked to the bezel 3 by increasing the mass m of the bezel 3 linked to the crystal 5. However, we prefer to lower the thickness of the spring-type membrane 2 to reduce the frequency f0du first mode of vibration by reducing the stiffness k of the membrane 2. The excitation of the membrane 2 is therefore done by a transmission of transverse waves generated by the vibration of one or more stamps 9 arranged below the dial in this first form of execution.

Such a membrane 2 in connection with the telescope 3 with the glass 5 or only in connection with the ice 5 can cover a band of acoustic radiation from 1 kHz to 10 kHz with the trim parts. If the thickness of the membrane 2 is reduced to reduce its stiffness following a manufacturing process by electroforming explained below, the acoustic radiation band may even be between 500 Hz to 10 kHz.

By way of nonlimiting example, provision may be made for having a sapphire crystal 5 with a thickness of 2 mm and a diameter of the order of 37.8 mm with a bezel 3 made of metal, such as l 'gold so as to have a mass of the order of 13 grams. The bezel 3 is of annular shape with an inside diameter of the order of 36 mm and an outside diameter of the order of 41.9 mm, and a thickness of the order of 3.55 mm. The membrane 2, which can be electroformed as explained below with reference to FIGS. 4a to 4e, can preferably be made of 5N gold to match the desired resonant frequency, since also a large part of the covering elements are Golden. The active zone 11 of the membrane may be a space between the telescope 3 and the complementary telescope 13 of 1.2 mm wide by 2 mm high in the Z direction.

Figures 2a to 2c show several embodiments of the annular membrane, a cross section of one side is shown, according to the invention. In FIG. 2a, the membrane 2 has an arcuate part 21, the circle portion angle of which is greater than 180 ° from the second border 20 to a straight part 22 connecting to the first border 23. In FIG. 2b, the membrane 2 has an arcuate part 21, the angle of the portion of a circle is substantially equal to 180 ° from the second border 20 to a straight part 22 connecting to the first border 23. In FIG. 2c, the membrane 2 has an arcuate part 21, the angle of the portion of a circle of which is substantially less than 180 ° from the second border 20 to a straight part 22 for connection to the first border 23.

The curvature of the membrane 2 in its active area can also play a role on its stiffness and also influence the lowering of the frequency of the first vibration mode under the effect of a force in the Z direction, given the reduced size, where the membrane 2 is located.

Preferably over the entire membrane 2, the thickness of the membrane is substantially the same, for example with a determined thickness which can be of the order of 80 μm and can be reduced to a thickness of the order of 37 µm to reduce the frequency of the first vibration mode to around 500 Hz for a 5N gold membrane with a bezel bonded to the ice as indicated above. This has the advantage of working at low frequency and obtaining a warmer, stronger sound, since there are several radiated modes interpreted by the human ear as a loud sound, and more distinguishable in the case of the reproduction of 'a set of notes to play a melody.

3 shows a partial cross-sectional view of a striking or musical watch having a membrane at the level of the crystal and the middle of the watch case according to a second embodiment of the invention. The only difference from this second embodiment resides in the second edge 20 of the membrane 2. This second edge comprises a heel 20 used to start manufacturing the membrane by electroforming. Once the membrane 2 has been made with its heel 20 of the second border, this heel, which is an annular gold ring for example, can be directly driven onto an external cylindrical wall at the bottom of the bezel 3. Thus this makes it possible to obtain a membrane 2 with one-piece fixing heel 20.

We will explain below a method of manufacturing the membrane to be mounted once completed in the striking watch. To do this, reference is made to FIGS. 4a to 4e.

In Figure 4a, there is obtained a metal ring of annular shape 20. Preferably, this annular ring 20 may be 5N gold even if other metallic materials can be considered.

In Figure 4b, there is provided a neckline substrate 30 as a basis for the production of the membrane by electroforming. This substrate has a profile complementary to the shape of the membrane to be produced. This substrate must be able to be dissolved at the end of the membrane manufacturing process without damaging the membrane. The substrate comprises an annular cavity 31 of dimension of the annular ring.

In Figure 4c, the annular ring 20 is driven into the annular cavity 31 of the substrate 30. This annular ring is at the mouth of the cavity and will serve as a starting point for the formation of the membrane.

In Figure 4d, the membrane is made from the heel 20 and on the substrate 30 of its complementary shape by electroforming with a metallic material such as 5N gold. Depending on the shape of the substrate, the membrane is formed with its annular arcuate part 21, its straight part 22 and the first border 23. The second border is linked directly to the heel 20.

Finally in Figure 4e, the substrate is dissolved to keep only the membrane with its parts 20 to 23. A refining can also be provided by immersing the membrane in an electroforming bath to complete the part in particular to refine its thickness. Subsequently, the membrane can be fixed in the striking watch, in particular between the movable bezel and the middle part.

From the description which has just been made, several variants of the striking or musical watch provided with the acoustic radiation membrane, and of the method of manufacturing the acoustic radiation membrane can be designed by man. of the trade without departing from the scope of the invention defined by the claims. Provision may be made to make the membrane by electroforming with a metal other than gold.

Claims (16)

1. Watch (1) with striking or musical device provided with at least one membrane (2) of acoustic radiation made of metallic material or amorphous metal, said membrane (2) being in the form of a wall loop of a certain thickness. to be connected by a first border (23) to a middle part (4) of a watch case and by a second border (20) to a bezel (3) fixed to a watch crystal (5) or directly to a crystal watch (5), the bezel (3) linked to the crystal (5) or the crystal (5) being movable relative to the middle (4) via the membrane (2) during the vibration of the membrane (2) following a sound generated by a watch striking mechanism in the watch case, characterized in that the membrane (2) is configured with a wall of a determined thickness in an active area (11) dependent on the mass of the telescope (3) linked to the ice (5) or the ice (5) only to have a frequency f0 of a first vibration mode, which is located at low frequency less than or equal to 4 kHz according to the equation f0 = (1 / 2π) · (k / m) <1/2> where k is the stiffness of the membrane (2), which depends on its thickness, and m is the mass of the telescope (3) linked to the ice (5) or the ice (5) alone. 2. Watch (1) according to claim 1, characterized in that the membrane (2) is of annular shape with an annular arcuate part (21) starting from the second edge (20) and directed in a direction of the glass (5 ) perpendicular to the plane of the watch (1), the arcuate part (21) extending by a straight part (22), which is connected to the first border (23). 3. Watch (1) according to claim 2, characterized in that the annular arcuate part (21) is a portion of a circle, in a cross section, whose angle at rest is greater than 180 °. 4. Watch (1) according to claim 2, characterized in that the annular arcuate part (21) is a portion of a circle, in a cross section, whose angle at rest is substantially equal to 180 °. 5. Watch (1) according to claim 2, characterized in that the annular arcuate part (21) is a portion of a circle, in a cross section, whose angle at rest is less than 180 °. 6. Watch (1) according to claim 2, characterized in that the annular arcuate part (21) and the straight part (22) have the same thickness. 7. Watch (1) according to claim 2, characterized in that the straight part (22) is of frustoconical shape. 8. Watch (1) according to claim 2, characterized in that the thickness of the membrane (2) between the first border (23) and the second border (20) is less than or equal to 80 µm to have a frequency f0d a first vibration mode less than or equal to 1 kHz in a vibration mode in conjunction with the telescope (3) or the glass (5). 9. Watch (1) according to claim 8, characterized in that the thickness of the membrane (2) between the first border (23) and the second border (20) is less than or equal to 40 µm to have a frequency f0d 'a first vibration mode of the order of 500 Hz in a vibration mode in conjunction with the telescope (3) or the glass (5). 10. Watch (1) according to claim 1, characterized in that the membrane is obtained by electroforming in 5N gold in connection with the bezel (3) in gold. 11. Watch (1) according to claim 1, characterized in that the second edge (20) of the membrane (2) is fixed by a fixing ring (10), which is driven out or welded to an external cylindrical wall at the bottom of the bezel (3). 12. Watch (1) according to claim 1, characterized in that the second border comprises a heel (20) obtained during the electroforming manufacture of the membrane (2), this heel being an annular ring for fixing the membrane (2 ) by driving on an outer cylindrical wall from the bottom of the telescope (3). 13. Watch (1) according to claim 1, characterized in that it comprises a complementary bezel (13) disposed above the bezel (3) and serving as protection, and for fixing the first edge (23) of the membrane (2) at an upper part of the middle part (4). 14. A method of manufacturing a membrane (2) for a watch (1) with a striking or musical device according to one of the preceding claims, characterized in that it comprises the steps of: - providing a neckline substrate (30) of a shape complementary to the membrane (2) to be produced, - make the membrane (2) on the substrate (30) by electroforming with a metallic material or amorphous metal, and - dissolving the substrate to keep only the membrane with a first border (23), a straight part (22), an arched part (21) and a second border (20) obtained with a determined thickness. 15. Method of manufacturing a membrane (2) for a watch (1) with a striking or musical device according to one of claims 1 to 13, characterized in that it comprises the steps of: - be provided with a metallic or amorphous metal annular ring (20), - providing a neckline substrate (30) of a shape complementary to the membrane (2) to be produced and comprising an annular cavity (31) in the shape of the annular ring (20), - driving out the annular ring (20) in the annular cavity (31) of the substrate (30), - make the membrane (2) from the heel (20) on the substrate (30) by electroforming with a metallic material or amorphous metal, and - dissolve the substrate to keep only the membrane with a first border (23), a straight part (22), an arched part (21) and a second border with the one-piece heel (20), the arched part and the right part being of the same determined thickness. 16. Method according to one of claims 14 and 15, characterized in that the membrane (2) with or without heel (20) is made of 5N gold.