EP4176321A1

EP4176321A1 - Timepiece comprising a vibration-amplifying device

Info

Publication number: EP4176321A1
Application number: EP21733804.5A
Authority: EP
Inventors: Sylvain Geiser; Quentin BENOIST
Original assignee: Patek Philippe SA Geneve
Current assignee: Patek Philippe SA Geneve
Priority date: 2020-07-01
Filing date: 2021-06-17
Publication date: 2023-05-10
Also published as: WO2022002622A1; JP2023532693A; CN115735164A; US20230259072A1

Abstract

The present invention relates to a timepiece (1) comprising a case (2) containing a movement, at least one vibration-generating device intended to produce at least one sound, at least one vibration-amplifying device (16) for amplifying the vibrations generated by the vibration-generating device, the vibration-amplifying device (16) comprising a lever (20) connected to a support (22) by a hinge about a single axis of rotation and arranged to be actuated by a transmission member (28) cooperating with the vibration-generating device in order to transmit the vibrations to the lever (20). The vibration-amplifying device (16) comprises at least one plate (18) arranged to cooperate with the lever in order to be moved according to a vibration movement, the plate (18) being housed in the case (2) in such a way as to form a free space around the periphery of the plate (18) over at least 70%, and preferably at least 80%, of the perimeter of the plate (18).

Description

WATCHMAKING PART INCLUDING AN AMPLIFIER DEVICE

VIBRATIONS

The present invention relates to a timepiece comprising a case containing a movement, at least one device generating vibrations intended to produce at least one sound, at least one device for amplifying the vibrations generated by said device generating vibrations, said device vibration amplification comprising a lever linked to a support by an articulation along a single axis of rotation, said lever being arranged to be actuated by a transmission member cooperating with the vibration generator device to transmit to said lever the vibrations in order to rotate relative to its support according to a vibration movement around its axis of rotation.

Such a timepiece is for example a striking watch (such as a minute repeater, large strike, small strike, alarm clock) for which the vibration generating device is for example a gong designed to be struck by a hammer when the ringtone is engaged to generate vibrations to produce sound. The gong is conventionally presented in the form of a wire wound around the movement. The gong is mounted integral with the frame (all of the plate and bridges) of the watch by means of a heel or gong holder, in order to transmit the vibrations of the gong to the entire watch (frame, movement , trim components). Thus the vibrations of the gong are transmitted to the wearer of the watch with maximum intensity.

As the transmission of sound is obtained by setting the entire watch into vibration, it has been proposed to stiffen the various elements of the watch in order to promote the vibration of these elements and thus improve said transmission of sound.

This solution gave satisfactory results in terms of sound transmission quality but caused other problems, such as the appearance of parasitic sounds. Indeed, the greater the sound intensity, the more the movement vibrates, and the more the different components of the movement generate noise while vibrating. This set of vibrations generates parasitic noises.

One solution to amplifying the sound is to increase the force of the hammer striking its tone. This made it possible to have a sound gain but the sound quality was degraded by extraneous noise.

The striking watch described in application EP 3644 133 proposes to solve this problem by using the waterproof sound transmission membrane implemented to seal the case in order to protect the movement and the striking device from humidity and dirt. The membrane may for example be held by an O-ring seal. Said waterproof sound transmission membrane is brought into contact with a sound transmission bridge integral with a movable part with a single degree of freedom in rotation, said movable part being associated with a heel bearing a stamp. Thus, the sound transmission bridge transmits vibrations of the heel, generated by those of the gong, when it is struck by its hammer, directly to the waterproof membrane in an optimal direction of vibration to vibrate said waterproof membrane, which increases the volume of sound perceptible outside the watch.

However, the waterproof membrane being by definition fixed on its periphery to an element of the box to guarantee the tightness, said membrane, when it receives the vibrations of the sound transmission bridge, is deformed by bulging in one direction and then in the direction. other in its first vibratory mode. These deformations generate significant damping, which adversely affects the quality of the sound. In addition, contact between the lever and the diaphragm can be achieved by preloading the lever on the diaphragm, which amplifies the damping. In the case of a fixed contact, the membrane would deform in a non-symmetrical way, which would add stresses.

The present invention aims to remedy these drawbacks by proposing a timepiece comprising a device for generating vibrations intended to produce at least one sound and a device for amplifying these vibrations allowing amplify said generated sound significantly, while preserving sound quality.

To this end, the present invention relates to a timepiece comprising a box containing a movement, at least one device for generating vibrations intended to produce at least one sound, at least one device for amplifying the vibrations generated by said device for generating sound. vibrations, said vibration amplifying device comprising a lever linked to a support by an articulation along a single axis of rotation, said lever being arranged to be actuated by a transmission member cooperating with the vibration generator device in order to transmit to said lever the vibrations in order to make it pivot relative to its support according to a vibratory movement about its axis of rotation.

According to the invention, the vibration amplification device comprises at least one plate arranged to cooperate with the lever in order to be moved according to a vibrating movement, said plate being housed in the box so as to form on the periphery of said plate a free space over at least 70%, preferably at least 80%, or even 100% of its perimeter.

Thus, when the plate receives the vibrations transmitted by the lever and enters into its vibrating movement, said plate, being substantially free to move, undergoes practically no deformation and acts as a piston on the air. Therefore, the sound produced by the timbre is greatly amplified while maintaining high quality.

According to a first embodiment, the plate is integral with the lever and moves with the lever in a rotational movement around the axis of rotation of said lever.

According to a first variant, the plate is fixed to the lever by its main surface, so that 100% of the periphery of the plate is free.

According to another variant, the plate is fixed to the lever by its peripheral edge, so that the amplification device will not be visible to a user. According to a second embodiment, the plate is arranged to cooperate with the lever so as to be driven by a linear translational movement along an axis perpendicular to the plate.

Advantageously, the plate cooperates with guide means in linear translation along said axis perpendicular to the plate in order to guarantee linear movement.

According to a first variant, said guide means comprise at least three flexible fasteners distributed regularly around the periphery of the plate and connecting said plate to a connecting support.

Thus, the first vibratory mode of the plate is a linear displacement of the entire plate by deflection of said fasteners.

According to another variant, the guide means consist of a bracket comprising a central plate secured to the plate and at least three elastic arms connecting the central plate to the box.

Such a bracket advantageously makes it possible to generate a linear movement of the entire plate, 100% of the periphery of the plate being free to move.

Other characteristics and advantages of the present invention will become apparent on reading the following detailed description of various embodiments of the invention, given by way of non-limiting examples, and made with reference to the accompanying drawings in which:

- Figure 1 is a bottom view of a timepiece according to a first variant of a first embodiment of the invention;

- Figure 2 is a perspective view of a timepiece according to the invention;

- Figure 3 is a schematic sectional view of the first variant of the first embodiment of the invention;

- Figure 4 is a perspective view of a lever used in the invention; - Figure 5 is a schematic bottom side view of another variant of the first embodiment of the invention;

- Figure 6 is a schematic bottom side view of another variant of the first embodiment of the invention;

- Figure 7 is a schematic sectional view of another variant of the first embodiment of the invention;

- Figure 8 is a view of a plate according to a first variant of a second embodiment of the invention;

- Figure 9 is a schematic sectional view of the plate of Figure 8 in its first vibratory mode;

- Figure 10 is a perspective and sectional view, from the bottom side, of a second variant of the second embodiment of the invention;

- Figure 11 is a perspective view from inside the box of Figure 10;

- Figure 12 is a sectional view of the plate of the stem and the lever according to the second variant of the second embodiment of the invention;

- Figure 13 is a perspective view of another embodiment of cooperation of the transmission member and the lever with the vibration generator device; and

- Figure 14 is a sectional view of the lever of Figure 4.

The present invention relates to a timepiece comprising a case containing a movement, at least one device for generating vibrations intended to produce at least one sound, at least one device for amplifying the vibrations generated by said device for generating vibrations, said device for vibration amplification comprising a lever linked to a support by an articulation according to a single degree of freedom in rotation, that is to say according to a single axis of rotation, said lever being arranged to be further actuated by a control member transmission not directly linked to said medium and cooperating with the device vibration generator for transmitting vibrations to said lever in order to make it pivot relative to its support according to a vibration movement about its axis of rotation, the vibration amplifying device comprising at least one plate arranged to cooperate with the lever and receive the vibrations amplified by the lever in order to be moved in a vibrational movement to exert pressure on the air in order to generate a sound from the inside to the outside of the timepiece, said plate being housed in the box so as to form on the perimeter of said plate a free space over at least 70%, preferably at least 80%, more preferably at least 90%, or even 100% depending on the variants, of the perimeter of said plate, free space through which a certain air flow can pass.

The vibration movement of the plate is amplified because the actuation point of the lever, the pivot point of the lever on the support and the link point of the lever with the plate are positioned so that a displacement of the transmission generated by the vibration of said transmission member in conjunction with the vibration generator device is transmitted to the plate by means of the lever, actuated by said transmission member, in a manner amplified by the leverage effect of said lever. Thus, the amplified vibratory displacement of the plate generates an amplified sound.

In addition, the plate is attached to the lever by a defined area, as small as possible, the rest of the plate being in a vacuum, and having no contact with any other part of the timepiece.

The plate is as large as possible to move, during its vibratory movement, as much air as possible, while leaving a free space around said plate through which air can pass in order to reduce the forces on the plate and dampen vibrations as little as possible, so as not to deteriorate the quality of the amplified sound. Thus the plate is free to move, without deformation, in order to vibrate with the least possible damping, to have a powerful and clean sound. The desired goal is to make the plate resonate with respect to the vibration generating device, so that the propagated sound lasts as long as possible.

The plate can be circular or polygonal, depending on the shape of the box.

The plate, in the rest state, may be substantially planar or be convex in the form of a shell, with a radius of curvature greater than the diameter of the watch, preferably greater than 30 mm, more preferably greater than 50 mm, and of preferably between 50 mm and 500 mm. The concave side of the curved plate is advantageously directed towards the outside of the box, on the sound outlet side, the lever being linked to the convex side of the plate. The reverse configuration is however possible.

In the present description, the term "plate" generally designates a flat or curved plate.

The plate is preferably made of a very light and rigid material in order to have a great dynamic response and not to deform, in its center but also on its free periphery, during its movement, as defined above.

Advantageously, the plate has a stiffness such that said plate has, over a frequency interval of at least two octaves, and for example between 1 kHz and 4 kHz, a piston behavior such as the average displacement of the points of the major area of the plate is greater than 50%, preferably greater than 75%, of the maximum displacement, i.e. the displacement of the point on the main surface of the plate that moves the most, so that the plate used in the present invention exhibits substantially no deformation over its entire surface, in particular at low frequency.

By way of comparison, a waterproof membrane traditionally used in a bell, the edges of which are fixed to the box, deforms according to a parabolic motion so that the average displacement of points on the membrane surface is less than 50% of the maximum displacement.

The plate is preferably made of a transparent material. For example, it can be made of sapphire, mineral glass, plexiglass, diamond, composite materials, cellulose, or composite glass of the safety glass type, etc.

Preferably, the plate is made of mineral glass, sapphire or diamond.

When the plate is used as a dial, as will be described below, the plate is preferably made of a non-transparent material, such as silicon, titanium, carbon or aluminum.

The plate must be as rigid and as light as possible. For this, its thickness is less than 1 mm, preferably less than or equal to 0.5 mm, preferably less than or equal to 0.15 mm, and more preferably less than or equal to 0.1 mm.

The vibration generator device may be a ringing bell arranged to be struck by a striking hammer, said ringing bell being integral with the transmission member, and said transmission member being integral with the lever.

In another variant, the vibration generator device may be a rotating disc and comprising an engraved groove arranged to generate a sound, the transmission member being a needle integral with the lever and arranged to follow the groove on the disc.

In another variant, the vibration generator device may be a music box comprising vibrating blades fixed by pads, the transmission member being integral with said pads and the lever.

In the following description, the vibration-generating device is a striking gong struck by a striking hammer so that the timepiece includes a striking mechanism to indicate the time (minute repeater, large strike, small strike) or to ring at a predefined time (alarm clock). The timepiece is preferably a watch, and more preferably a wristwatch intended to be worn by a user, on his wrist.

Unless specifically indicated, the remainder of the description of the invention, in particular of the vibration amplification device, will apply in the same way to a watch comprising a music box or a rotating disc read by a needle, one end of which is integral with the lever and the other end is arranged to read the groove engraved on the rotating disc. The needle is mounted on the lever, for example by embedding or soldering, for example by being introduced into a hole provided for this purpose on the lever.

Referring to Figures 1 and 2, watch 1 comprises a case 2 having a caseband 3, a caseback 4, a bezel 5, and a first crystal 6. The caseback 4 is annular and its central opening is closed by a second crystal 7 The bezel and the middle part can be two different parts, or form a single one-piece part. Likewise, the back and the middle part can be two different parts or form a single one-piece part.

In the following description, the vibration amplifying device and the plate are arranged to generate sounds from the back of the watch. It is obvious that the vibration amplifying device and the plate can be arranged in a similar way but in reverse to generate sounds on the dial side of the watch.

With reference more specifically to FIG. 1, watch 1 also comprises a movement and a striking mechanism 9 constituting the device generating vibrations intended to produce at least one sound. The movement and the striking mechanism 9 are housed in the middle part 3 of the box 2, mounted on a frame 10 (plate and bridges). The striking mechanism 9 comprises, in a known manner, hammers 12 arranged to strike the striking bell 14, here in the form of a wire or leaf spring wound around the movement.

In order to amplify the sounds produced by the gong 14, there is provided a device 16 for amplifying the vibrations generated by the gong 14 comprising a lever 20 linked to a support 22 by an articulation along a single axis of rotation 21, so that said lever is mounted to tilt or pivot on said support 22 about said axis of rotation 21, as well as a plate 18 (cf. FIGS. 3 et seq. ) arranged to receive said amplified vibrations and generate an amplified sound from the inside to the outside of the watch. When the sound is transmitted on the bottom side, the plate 18 is mounted on the bottom 4 side, being positioned parallel to said bottom 4 at least when it is in a rest position, not subjected to vibrations, between the movement and the second crystal 7 It will be mounted inside the bezel 5, being positioned parallel to said bezel 5 at least when it is in its rest position, between the movement and the first crystal 6 when the sound will be transmitted to the dial side.

In a particularly preferred manner, the lever 20 and the plate 18 are arranged with respect to each other such that the axis of rotation 21 of the lever 20 is parallel to the plane of the main surfaces of the plate 18 at the same time. less when said plate 18 is in its rest position. It is considered that the other degrees of freedom of the lever 20 are negligible compared to its degree of freedom in rotation about its axis of rotation 21.

Referring to Figures 3, 7, 10 and 11, the lever 20 is arranged to be actuated by a transmission member 28 cooperating with the gong 14 to transmit to the lever 20 the vibrations. The transmission member 28 is positioned on the same side as the lever 20 relative to the articulation 21 of said lever 20 with the support 22 so that the transmission member 28 is not directly linked to the support 22 on which the lever 20 is mounted articulated. The transmission member 28 is preferably integral with the lever 20. The transmission member 28 may consist for example of a heel or gong holder integral with the lever 20 and in which the gong 14 is mounted, for example by fitting. , locking by a screw or soldering. To this end, the transmission member 28 comprises for example an orifice 30 into which the stamp 14 is introduced. Thus, the gong 14 is integral with the lever 20 and is not fixed, via a heel, on the frame of the watch. The transmission organ 28 can be attached or in one piece with the lever 20, as shown in Figures 3, 7, 10 and 11. When the transmission member 28 is in one piece with the lever 20, the gong is assembled directly lever, by welding for example.

According to another variant not shown, the transmission member 28 may be in one piece with the lever 20, being arranged to form a clamp in which the gong 14 is held. This arrangement makes it possible to limit the loss of vibration as much as possible.

According to another variant shown in FIG. 13, the transmission member 28, which is advantageously in one piece with the lever 20, does not carry the gong 14 and does not constitute the heel of the gong 14, but is designed to cooperate with the gong 14 by contact in order to be able to pick up the vibrations of the gong 14 and actuate the lever 20 accordingly to transmit the vibrations picked up to the plate 18. The transmission member 28 can cooperate with the gong 14 by simple contact or present the shape of a clamp. The gong 14 is then fixed on a heel 64 fixed preferably on an element of the case, such as the caseband or the back, or possibly on an element of the movement. Preferably, the point of capture of the transmission member 28 on the stamp 14 is relatively close to the heel embedment area. In this configuration, the vibration capture point by lever 20 is advantageously positioned on gong 14 and not on its heel, in order to have low vibration damping, the amplitude of the signal being greater.

Advantageously, the material of the lever 20, the gong 14 and the transmission member 28 is chosen to make these three elements in one piece. This material is chosen as transporting vibrations, for example steel or magnesium.

Advantageously, the vibration amplification device, and more particularly the support 22 of the lever 20 is isolated from the movement, the striking mechanism 9 and the frame 10. For this purpose, the support 22 of the lever 20 can be mounted on an element of the casing and more particularly on the bezel 5 if the sound is transmitted on the dial side, on the back 4, if the sound is transmitted through the back. When the ringing gong 14 is embedded in the transmission member 28 integral with the lever 20, said gong 14 is not fixed to the frame via a heel, as traditionally, but seems to float around the movement.

The support 22 of the lever 20 can also be mounted on the movement, or even on the middle part 3, but advantageously by means of an insulating element, such as a polymer, in order to guarantee the isolation of the support 22 from the movement, of the middle and the frame.

When the support 22 of the lever 20 is mounted on the bezel 5, respectively on the bottom 4, said bezel 5, respectively said bottom 4 can be assembled directly on the middle part 3 in a conventional manner. However, in order to ensure that no parasitic vibration will occur on the middle part 3 and therefore on the movement, said bezel 5, respectively said bottom 4 is advantageously assembled on the middle part 3 by means of an insulating element, such as than a polymer.

Since the plate 18 is also isolated from the movement and the striking mechanism 9, the vibration amplifying device and the plate are isolated from the movement and the frame so that all the vibrations of the gong picked up by the lever 20 are directed and transmitted to the plate 18, without transmission to the movement, to the frame or to the caseband.

The lever 20 is preferably made of a very light and very rigid material. For example, the lever 20 can be made of steel, titanium, aluminum, magnesium, composite material, carbon, glass, sapphire and ceramic.

Advantageously, the lever 20 can be mounted articulated or pivoting on the support 22 by means of a single central flexible ball joint 24 as shown in FIG. 1. The flexible ball joint (more precisely the flexible pivot since it is an articulation according to the single axis of rotation 21) makes it possible, if necessary, to modify the direction of the vibrations. In particular, in the case of the ringing tone, the latter tends to vibrate radially, in the direction of the hammer strike. Preferably, the position of the flexible ball 24 (ie of the flexible pivot) of the lever 20 makes it possible to modify the direction of the radial vibrations of the gong by 90 ° to transform them into a movement of vibrations perpendicular to the plane defined by the bottom for example, that is to say the plane defined by the plate 18 when it is in the rest position, by means of the pivoting of said lever 20. Preferably, the flexible ball 24 (ie the flexible pivot) is positioned on the center of mass of the stamp / lever / plate assembly.

As shown in Figure 4, the lever 20 can be mounted articulated or pivoting on the support 20 by means of two ball joints or flexible pivots 24, disposed on the outside as far apart as possible from each other, in order to 'ensure better guiding of the plate 18 by reducing parasitic movements, in particular lateral movements.

Advantageously, the thickness e of the wall of the flexible ball joint 24 (ie of the flexible pivot) as shown in FIGS. 4 and 14 can be modified in order to vary the frequency of vibration of the lever 20 and of the plate 18, and consequently the length of the sound generated. Preferably, the thickness e is chosen so that the vibration frequency of the lever 20 / plate 18 assembly is a multiple of the natural frequency of the gong 14 so that the lever / plate system resonates with the gong, which will decrease the damping of the sound and therefore increase the length of the sound. When several timbres are used, we can choose, as frequency, an average value of the frequencies.

The thickness of the lever 20 can be chosen to be greater on the side of the axis of rotation 21 and to decrease in the direction of the plate 18, in order to keep as much rigidity as possible and to reduce the inertia of the system.

It is also possible to mount the articulated or pivoting lever 20 on the support 22 by means of a pin mounted transversely on the support 22 and constituting the axis of rotation 21 of the lever 20. The support 22 is then constrained by a spring. More specifically, the lever 20 comprises a first end 20a hinged or pivoting on the support 22 and integral with the transmission member 28 and a second end 20b arranged to cooperate with the plate 18. The length of the lever 20 is that is to say, the distance between its first end 20a and its second end 20b varies according to the variants of the invention.

According to a first embodiment of the invention, the plate 18 is integral with the lever 20, being fixed to said lever 20 by a defined zone, and moves with said lever 20 according to a vibratory rotational movement around the axis of rotation 21 of said lever 20, that is to say according to the same degree of freedom in rotation as the lever 20.

The plate 18 comprises two main surfaces 18a, 18b parallel to the dial and to the bottom when said plate 18 is in its rest position, that is to say a face 18a on the bottom side and a face 18b on the dial side, said main surfaces 18a , 18b being joined by a side edge 18c.

According to a first variant of this first embodiment shown in FIG. 3, the plate 18 is fixed to the lever 20 by one of its main surfaces, here by its face 18b on the dial side, so that 100% of the periphery of the plate 18 is free. The fixing of the lever 20 to the plate 18 can be done for example by means of a screw 32 screwed into a hole provided on the plate 18 and in a hole 34 (see Figure 4) provided at the second end 20b of the lever 20 , or by gluing, welding, etc.

The volume of air displaced will be greater on the zone of the plate 18 furthest from the axis of rotation 21, represented by the arrows in FIG. 3. Furthermore, the plate 18 moving parallel to the lever 20, it It is possible to put an extremely small or even zero play between the plate and the lever, which makes it possible to reduce the bulk.

According to another variant shown in Figure 5, the plate 18 can be cut to include a radial opening 36 in which is housed the lever. 20, without contact with the plate 18 on either side of the radial opening 36. This allows the lever 20 to be integrated into said radial opening 36, by passing it through said radial opening 36, which makes it possible to reduce clutter.

It is also possible to provide for perforating certain areas of the plate 18 in order to integrate said plate 18 into the movement. This helps reduce clutter. Preferably, said perforated zones are positioned where the efficiency is the lowest.

According to another variant shown in FIG. 6, the timepiece comprises at least two vibration generating devices distributed inside the box 2, for example two different gongs 14 ', 14 ”, at least two levers 20' , 20 ”articulated respectively on their support 22 ', 22”, and respectively carrying the stamps 14', 14 ”, and at least a first plate 18 'associated with one of the levers 14' and a second plate 14” associated with the other lever 14 ”. Said first and second plates 18 ', 18 ”may have complementary shapes chosen to occupy the interior space of the box 2, leaving an entirely free space between said plates 18', 18” and the peripheral edge of the element of. box 2 as close as possible to said plates, in accordance with the invention. A free space 23 is also formed between said plates 18 ', 18 ”to allow said plates 18', 18” to move freely independently of each other, according to their own vibrational movement, depending on the vibratory movements of their respective levers 20 ', 20 ”. It is thus possible to amplify the sources in different ways. For example, it is possible to set a high tone and a bass tone differently. In the case of a minute repeater, it is for example possible to adjust the hour stamp and the minute stamp independently.

The 14 ", 14" stamps can be positioned around the 18 ", 18" plates facing each other or at any other location. It is obvious that it is possible to provide more than two stamps.

According to another variant of the first embodiment of the invention shown in Figure 7, the plate 18 is fixed to the lever 20 by its edge peripheral, for example by embedding. To this end, the lever 20 has a groove 38 forming a fitting clamp in which the plate 18 is held, by the periphery of these main faces 18a, 18b, compressed by the lever 20. In another variant not shown, it an additional plate is provided which makes it possible to fix the plate 18, by the periphery of these main faces 18a, 18b, on the upper face of the lever 20. The plate 18 can be compressed, by the periphery of the main faces 18a, 18b between the plate and the upper face of the lever 20, or the periphery of the main face 18a of the plate is glued under the plate which is itself screwed onto the upper face of the lever 20, the periphery of the main face 18b being in contact with said upper face of lever 20. The length of lever 20 is reduced accordingly to correspond substantially only to the length of the mounting clamp or to the area necessary to maintain the periphery of the main faces ales 18a, 18b of plate 18. Thus, there is no element which passes over the movement or over the dial. The amplification device will then not be visible to a user, which is particularly advantageous when the plate 18 is on the dial side.

In order to combine the rigidity and lightness of the plate 18, said plate can advantageously have a thickness which increases from the peripheral edge to which the lever 20 is fixed to the free opposite peripheral edge. The rigidity is greater near the point of attachment to the lever 20 and the lightness is greater on the area of the plate that is furthest away.

Advantageously, the plate 18, when it is on the dial side, can be arranged to constitute a dial itself, by being drilled in the center for the passage of the hands. Preferably, the dial is transferred, without applique or other added element so as not to increase the weight of the plate.

In these variants, the lever 20 advantageously comprises the two ball joints or flexible pivots 24 described above with reference to FIG. 4, in order to ensure the guiding of the plate 18. In another variant not shown, the plate 18 can be made in a single piece with the lever 20 and the support 22 so that the lever 20 and the support 22 are advantageously formed by a rim of the plate 18, directly embedded in an element. of box 2, the rest of the plate being in a vacuum, in order to be able to vibrate freely. The stamp heel is fixed directly on the plate, close to its point of embedding in the element of the box 2. The stamp heel and the plate can be made in one piece.

According to a second embodiment of the invention, the plate 18 is arranged to cooperate with the lever 20 so that the whole of the plate 18 is driven by a linear translational movement along an axis perpendicular to said plate 18, l 'axis of rotation 21 of lever 20 and plate 18 remaining parallel in vibratory mode. This means that all the points on the plate move with the same linear translational movement.

Preferably, the point of connection of the lever 20 with the plate 18 is located at a distance from the center of said plate 18 of less than 40%, preferably less than 20%, of the width of said plate 18. Particularly preferably, the point of connection of the lever 20 with the plate 18 is located in the center of said plate 18, in order to have a maximum lever arm effect.

Advantageously, the plate 18 cooperates with guide means in linear translation along said axis perpendicular to the plate in order to ensure that the movement remains linear.

According to a first variant of the second embodiment shown in Figures 8 and 9, said guide means comprise at least three flexible fasteners 40 distributed regularly around the periphery of the plate 18 and connecting said plate 18 to a connecting support 42, integral for example an element of box 2.

Thus, the first vibratory mode of the plate is a linear displacement of the entire plate 18 by deflection of said fasteners 40 which guide the vibratory displacement of the plate 18 and the lever 20, as shown in Figure 9.

Said connection support 42 constitutes in this variant the element of the box 2 as close as possible to the plate 18, delimiting with the plate 18 the free space 44 around the plate 18, between the connection support 42 and said plate 18 .

When the plate 18 is circular, the clips 40 may be three in number, spaced from each other at an angle of 120 °, or more than three. This principle makes it possible to reinforce the low frequencies by resonance of the plate-elastic fastener system. The shape of the fasteners and their number can vary in order to determine the resonant frequencies of the plate-fastener system. For example, according to a variant not shown, the fasteners may extend concentrically to the plate, and be three or more in number.

The dimensions, and in particular the length, of the fasteners 40 are chosen to manage the flexibility (compliance) of said fasteners. Thus, a greater length makes it possible to increase the flexibility of the fasteners 40.

Advantageously, the flexible or flexible fasteners 40 and the connecting support 42 have been formed by cutting in the plate 18, for example by laser. Laser cutting has the advantage of forming very precisely the fasteners 40 so as to make the plate 18 resonate with the stamp 14. This also makes it possible to precisely size the width of the space 44 between the plate 18 and the connection support 42, in order to manage the flow of air passing from said space 44, as will be described below. Advantageously, the width of the clips 40 is such that at least 70%, preferably at least 90% of the perimeter of the plate is free to move.

According to another variant of the second embodiment of the invention, shown in Figures 10 to 12, the guide means may be constituted by a bracket 46 comprising a central plate 48 integral with the plate 18 and at least three elastic arms 50 connecting the central plate 48 to an element of the box 2, such as the middle part 3. Preferably, the arms 50 are distributed regularly around the central plate 48 and have a great length giving them a certain elasticity or flexibility to guarantee linear guidance. They can be attached to the element of the box 2, for example the caseband 3, held by a seal 52. They can also be formed integrally with the element of the box 2.

The plate 18 is integral with the central plate 48, for example by screwing, gluing, welding or any other suitable fixing means. The plate 18 is fixed to the central plate 48 by its center so that 100% of the periphery of the plate 18 is free to move.

In order to have a perfectly linear vibratory movement of the plate 18, without deformation of the plate, said plate 18 is preferably coupled to the lever by a spherical connection.

Such a spherical connection can be provided by an additional flexible ball joint provided at the second end 20b of the lever 20 between said lever and the central plate 48.

Advantageously, and with more particular reference to FIG. 12, such a spherical connection can also be ensured by providing on the central plate 48 of the bracket 46 a contact zone 54 with the second free end 20b of the lever 20, said contact zone 54 and said second free end 20b of lever 20 being rounded. In addition, the central plate 48 and the second free end 20b of the lever 20 respectively comprise a central channel 56, 58, perpendicular to the main plane of the plate 18, communicating with one another. A prestressed elastic thread 60, such as a nylon thread, passes through said channels 56, 58, one end of the elastic thread 60 being integral with the central plate 48 and the other end of the elastic thread 60 being integral with the second free end 20b. of the lever 20. The ends of the wire 60 can be fixed to the plate 48 and to the lever 20 respectively by gluing, for example. This arrangement makes it possible to couple the lever 20 and the plate 18 by a flexible fixing and to guarantee contact between the lever 20 and the plate 18 without constraint. Independently of the embodiments, and in an advantageous manner, the free space formed around the plate 18 has, between said plate 18 and the peripheral edge of the element of the box 2 as close as possible to the plate, a width between 10 pm and 500 pm, preferably between 10 pm and 400 pm, preferentially between 10 pm and 300 pm, and more preferably between 30 pm and 60 pm. A width of less than 10 μm may be considered depending on the technologies available. The same is true for the free space left between the plates, when several plates are used as shown in Figure 6.

The free space formed around the plate 18 is necessary to work in piston mode and thus reduce the internal friction in said plate 18, but it generates a leak, which must then be dimensioned to be as small as possible in order to reduce the loss. sound power.

The free space is also dimensioned with respect to the openings 62 (see Figure 2) provided for example laterally on the box 2 and through which the amplified sound comes out. The leak and the openings 62 can be characterized by their acoustic resistance. The openings 62 have an acoustic resistance much lower than that of the leak so that the majority of the compressed air exits through said openings 62 to propagate the amplified sound. Preferably, the ratio of the acoustic resistances in the useful frequency range between the leak and the openings 62 is at least 2 and preferably 5.

The openings 62 can advantageously be closed by modular shutter means arranged to be able to adjust the volume of the sound generated by the plate 18 or arranged to close the openings 62 once the sound has been generated, for example outside the ringing time. These closure means are arranged to be able to be moved between a closed position in which the opening 62 is fully closed and an open position in which the opening 62 is maximum, the intermediate positions making it possible to block more or less l. opening 62 to adjust the sound volume. For example, the closure means may comprise a rotating element such as a ring, mounted in rotation on the bottom 4, and arranged to rotate between a closed position in which the opening 62 is completely blocked and an open position in which the opening 62 is maximum.

Advantageously when looking to have a sealed timepiece, each opening 62 can be protected by a filter permeable to air and impermeable to water, in order to prevent impurities or water does not fit in the box. Such filters are known to those skilled in the art.

The timepiece according to the invention allows a significant amplification of the sound by means of an articulated lever which directs the vibrations of the sound source in the correct axis, while preserving the quality of the sound, which undergoes practically no damping of the sound. makes use of a free plate around which air can pass, so that the plate no longer undergoes deformation stress. Unlike a device using a waterproof membrane for which the damping of vibrations is very important, the propagated sounds being very strong but very short, the present invention makes it possible to obtain resonance, with strong propagated sounds, of good quality and lasting. the longest time possible.

For most of the examples described above, only one stamp is shown. It is obvious that several stamps can be used in the same way.

Claims

1. Timepiece (1) comprising a box (2) containing a movement, at least one device for generating vibrations intended to produce at least one sound, at least one device (16) for amplifying the vibrations generated by said device. vibration generator, said vibration amplifying device (16) comprising a lever (20) linked to a support (22) by an articulation along a single axis of rotation (21), said lever being arranged to be actuated by a member transmission (28) cooperating with the vibration generator device to transmit to said lever (20) the vibrations in order to rotate said lever (20) relative to its support (22) according to a vibratory movement around its axis of rotation ( 21), characterized in that the device (16) for amplifying the vibrations comprises at least one plate (18) arranged to cooperate with the lever in order to be moved according to a vibrational movement, and in that said plate (18) ) is housed in ns the box (2) so as to form on the periphery of said plate (18) a free space on at least 70%, preferably at least 80%, of the perimeter of said plate (18).

2. Timepiece according to claim 1, characterized in that said plate (18) has a stiffness such that said plate (18) has over a frequency interval of at least two octaves a piston behavior such as displacement. average of the points on the surface of the plate is greater than 50%, preferably greater than 75%, of the maximum displacement.

3. Timepiece according to one of claims 1 and 2, characterized in that the plate (18) is integral with the lever (20) and moves with the lever (20) in a rotational movement around the axis of rotation (21) of said lever (20).

4. Timepiece according to claim 3, characterized in that the plate (18) is fixed to the lever (20) by its main surface.

5. Timepiece according to claim 4, characterized in that the plate (18) comprises an opening (36) in which the lever (20) is housed.

6. Timepiece according to claim 3, characterized in that the plate (18) is fixed to the lever (20) by its peripheral edge.

7. Timepiece according to one of claims 1 to 6, characterized in that the lever (20) is mounted articulated on the support (22) by means of two flexible ball joints (24) arranged so as to be spaced l 'from each other as much as possible.

8. Timepiece according to one of claims 3 to 7, characterized in that it comprises at least two vibration generating devices, at least two levers (20 ', 20 ”), and at least a first plate ( 18 ') associated with one of the levers (20') and a second plate (18 ”) associated with the other lever (20”), said first and second plates (18 ', 18 ”) being free to move independently of each other according to their own vibrational movement.

9. Timepiece according to one of claims 1 and 2, characterized in that the plate (18) is arranged to cooperate with the lever (20) so as to be driven by a linear translational movement along an axis. perpendicular to the plate (18).

10. Timepiece according to claim 9, characterized in that the plate (18) cooperates with guide means in linear translation along said axis perpendicular to the plate (18).

11. Timepiece according to claim 10, characterized in that said guide means comprise at least three flexible fasteners (40) distributed regularly around the periphery of the plate (18) and connecting said plate (18) to a support for link (42).

12. Timepiece according to claim 11, characterized in that said fasteners (40) and the connecting support (42) have been formed by cutting in the plate (18).

13. Timepiece according to claim 10, characterized in that said guide means are constituted by a bracket (46) comprising a central plate (48) integral with the plate (18) and at least three elastic arms (50) connecting the central plate (48) to the box (2).

14. Timepiece according to one of claims 9 to 13, characterized in that the plate (18) is coupled to the lever (20) by a spherical connection.

15. Timepiece according to claims 13 and 14, characterized in that the central plate (48) of the stem (46) comprises a contact zone (54) with the free end (20b) of the lever (20). , said contact zone (54) and said free end (20b) being rounded, in that the central plate (48) and the free end (20b) of the lever (20) respectively comprise a central channel (56, 58) perpendicular to the plate (18), communicating with one another, and in that a prestressed elastic wire (60) passes through said channels (56, 58), one end of the elastic wire (60) being integral with the plate central (48) and the other end of the elastic thread (60) being integral with the free end (20b) of the lever (20).

16. Timepiece according to one of the preceding claims, characterized in that the free space formed around the plate (18) has, between said plate (18) and the peripheral edge of the box (2) at most near the plate (18), a width of between 10 µm and 500 µm, and preferably between 30 µm and 60 µm.

17. Timepiece according to one of the preceding claims, characterized in that the vibration generator device is a striking gong (14) arranged to be struck by a striking hammer (12), said striking gong (14) ) being integral with the transmission member (28), said transmission member (28) being integral with the lever (20).

18. Timepiece according to one of claims 1 to 16, characterized in that the vibration generator device is a rotating disc and comprising an engraved groove arranged to generate a sound, the transmission member (28) being a needle integral with the lever (20) and arranged to follow the groove on the disc.