Vibrating patch and associated striking mechanism

Abstract

Tuning fork gong (2) for a striking mechanism (1) of a wristwatch, characterized in that it comprises a fixing stem (21) extending along a first arc of a circle (A1) from a base (210) to a vertex (211) on a first angular sector, the fixing stem (21) being extended by a first branch (22A) extending along a second arc of a circle (A2) and a second branch (22B) extending along a third arc of a circle (A3). The second and third arcs of a circle (A2, A3) are formed on concentric circles in the plane of the plate (P) or circles superimposed in a direction (D) perpendicular to said plane of the plate (P); the first branch (22A) and the second branch (22B) also extend over a second identical angular sector.The tuning fork (1) extends in its entirety over a total angular sector of angle (α0) strictly less than 360 degrees equal to the sum of a first angle (α1) corresponding to the first angular sector and a second angle (α2) corresponding to the second angular sector.

Description

Technical field of the invention

[0001] The present invention relates to the field of watchmaking and grand complications. More specifically, the invention relates to a vibrating gong and an associated striking mechanism. State of the art

[0002] In the field of watchmaking and watches equipped with striking mechanisms, gongs have long since replaced bells, taking up far too much space. These gongs consist of arcuate metal blades or strands, most often arranged around the periphery of the movement, one or both ends of which can be connected to the plate. Since the development of grand complications, and in particular grand sonneries and minute repeaters, there have been numerous examples of watches equipped with such vibrating elements intended to be activated by hammers.

[0003] The striking of the hammer causes oscillations of the gong which in turn generate sound waves associated with a particular sound. This sound can then be adjusted by a master watchmaker in particular via the intensity of the strike, that is to say the force exerted on the gong, as well as the striking position on the gong. More generally, the acoustic qualities of the sound emitted (that is to say the frequency corresponding to a pitch and therefore a predetermined note, the sound volume generated, the harmonic spectrum corresponding to a particular acoustic timbre, as well as the vibration duration) still depend on the shape and material of the gong, as well as its mechanical coupling to the plate, and / or of the latter to the watch case, the latter acting as resonators. In general, the gong(s) are fixed to the plate by means of metal studs, on which they are for example set or soldered.These studs, usually referred to as stamp holders, are then generally screwed to the plate.

[0004] To generate two different sounds, particularly in the context of minute repeaters, it is possible to arrange two gongs of different length and section, each being actuated by an associated hammer with a striking force and in a predetermined position. An example of such a striking mechanism is described for example in Swiss patent application CH708036, where each of the two gongs is arranged in the plane of the plate and connected to the same gong holder.

[0005] In order to improve the sound quality of classical gongs, whose length is limited, we also know the so-called "cathedral" gongs. These gongs have the particularity of having a length of almost twice that of classical gongs, that is to say extending over an angular sector of almost 720°, corresponding therefore to almost two complete revolutions around the plate. Such gongs, intended to enrich the sound and the length of the resonance time, however have some disadvantages in terms of arrangement on the plate, because the gong is intended to be fixed at only one of its ends, and requires a helical arrangement to vibrate over its entire length in order not to touch any of the elements of either the movement or the case.

[0006] Other forms of timbres are also known, such as so-called "ribbon" timbres, i.e. a timbre with a very thin rectangular section forming a cylindrical strip, which makes it easier to accommodate them on the periphery of the turntable. However, such ribbons do not offer optimal acoustics and require, as in the solution described in Swiss patent CH707061, a particular shape at the attachment point in order to generate the desired resonance.

[0007] An object of the proposed invention is to provide an exemplary solution to these known drawbacks. Summary of the invention

[0008] In particular, an aim of the present invention is to provide a new solution for a striking mechanism, using a gong of a particular shape whose acoustic properties are improved compared to conventional gongs, and whose production as well as integration on the plate and in the case are facilitated.

[0009] These aims are achieved according to the invention thanks to the characteristics of the main claims, and in particular thanks to a tuning fork gong for a striking mechanism of a wristwatch, characterized in that it comprises a fixing rod extending along a first arc of a circle from a base to a vertex on a first angular sector, the fixing rod being extended by a first branch extending along a second arc of a circle and a second branch extending along a third arc of a circle, the second and third arcs of a circle being formed on concentric circles in the plane of the plate or circles superimposed in a direction perpendicular to the plane of the plate;the first branch and the second branch also extend over a second identical angular sector, and the tuning fork extending, in its entirety, over a total angular sector of angle strictly less than 360 degrees equal to the sum of a first angle corresponding to the first angular sector and a second angle corresponding to the second angular sector.;

[0010] An advantage of the proposed solution is that it allows the length of the gong to be significantly extended, and thus the resonance time, i.e. the duration of the emitted sound, can be increased, while at the same time lowering its frequency to give it a lower and more intense character, without having to go back to an angular position corresponding to the location of the gong holder on the plate. Thus, an interesting alternative to the cathedral gong is proposed by emulating the preferred sound characteristics of such a gong, but without having to face the disadvantages in terms of arrangement on the plate and in the case, as well as for the fixing of such a gong.

[0011] According to a preferred embodiment, the tuning fork gong for a striking mechanism of a wristwatch according to the invention is characterized in that the angle corresponding to the first angular sector is less than that of the second angular sector.

[0012] In this way, the extension of the useful length of the timbre, that is to say by adding the length of the rod and that of the two branches, is maximized, which allows to improve the sound performance as much as possible compared to known single-blade timbres.

[0013] According to another preferred embodiment, the tuning fork gong for a striking mechanism of a wristwatch according to the invention, the bifurcation between the fixing stem and the branches at the top of the stem is carried out via a branch having a rounded shape.

[0014] In other words, the bifurcation is U-shaped, i.e. without forming any obtuse or protruding angles. In this way, the transmission of vibrations is improved and the quality of the sound produced is therefore also optimized.

[0015] According to yet another preferred embodiment, the tuning fork gong for a striking mechanism of a wristwatch according to the invention, the first angular sector is between 10 and 20 degrees, and the second angular sector is between 300 and 320 degrees.

[0016] In this way, the length of the fixing rod is reduced to a minimum, while that of the branches is maximized so as to approach as closely as possible the sound of a cathedral gong which, with its two complete revolutions, would correspond to a useful length extending over an angular sector of approximately 720 degrees, while leaving a sufficiently large angular sector (greater than 40 degrees) to place the gong holder on the plate, and leave in parallel the ends of the branches of the tuning fork gong free and resonate without constraint.

[0017] The tuning fork gong for a striking mechanism of a wristwatch according to the invention can have a shape corresponding to two distinct variants: Either the first branch and the second branch are arranged concentrically in the plane of the plate; or the first branch and the second branch are superimposed on each other in a direction perpendicular to the plane of the plate.

[0018] In the first case, the tuning fork is arranged in a radial direction, i.e. towards the periphery of the plate, and the space requirement is therefore greatest towards the inside of the plate. Nevertheless, this variant can have an advantage over the hammer configuration and transmit the vibration indirectly from one branch to the other in the event of striking in a radial direction towards the outside.

[0019] In the second case, the tuning fork is arranged in the opposite direction in the height, corresponding to the direction perpendicular to the plate. In this case, however, the space available for a movement encircled by the gong is maximized.

[0020] According to yet another preferred embodiment, the tuning fork gong for a striking mechanism of a wristwatch according to the invention is characterized in that the fixing stem has a first constant section, and the first branch as well as the second branch have the same second constant section.

[0021] In this way, the symmetry of the tuning fork is optimized and the acoustic properties as well. Most single-reed gongs generally have a constant section but which often needs to have notches in order to adjust the sound characteristics (modifications of the desired timbre, the note, or even the vibration duration). This can be achieved by adjusting the second section relative to the first, while maintaining advantageous symmetry properties.

[0022] According to an even more preferred embodiment, the tuning fork gong for a striking mechanism of a wristwatch according to the invention is characterized in that the first section and second section are square and identical.

[0023] In this way, thanks to the square section of the tuning fork gong, its machining is simplified to the maximum, and such a configuration also makes it easier to create decorative patterns face to face. Furthermore, the equality of the sections between the fixing rod and the branches makes it possible to get even closer to the philosophy of a cathedral-type gong, insofar as the branches then virtually constitute an exact extension of the useful length of the same vibrating blade of a gong by doubling, the blades of the two branches having almost identical properties (section and radius of curvature). The acoustic properties of the tuning fork gong thus produced are further improved.

[0024] According to yet another preferred embodiment, the tuning fork gong for a striking mechanism of a wristwatch according to the invention is characterized in that the first branch and the second branch are spaced apart by a spacing greater than the width of the first section.

[0025] Thanks to such a configuration, the spacing is sufficient so that the vibration of each of the branches is neither hindered nor disturbed by the other via the creation of excessive interference.

[0026] The present invention also relates to a striking mechanism of a wristwatch comprising a tuning fork gong according to one of claims 1 to 9, and further comprising a hammer pivoting about a pivot axis and which is arranged to strike the tuning fork gong in a predetermined position on one of the branches chosen from the first branch and the second branch.

[0027] Such a configuration allows vibrations to be transmitted much more efficiently indirectly from one branch to another than actuating the vibration of the gong via the fixing rod, which is less easily deformed and closer to the gong holder.

[0028] According to a preferred embodiment for the striking mechanism, the base of the fixing rod is fixed to a gong holder, but the first end of the first branch as well as the second end of the second branch are free.

[0029] In this way, the structure of the tuning fork is very close to that of a musical tuning fork, except that its branches are arched and not straight. However, the activation of such a tuning fork is also optimized by striking one of the two branches.

[0030] According to an even more preferred embodiment for implementing the invention, the striking mechanism comprises two tuning fork gongs formed respectively by an upper gong and a lower gong, the base of the upper gong stem being extended in a single piece by a first fixing heel and the base of the lower gong stem being extended in a single piece by a second fixing heel, the first heel and the second fixing heel being separated by a spacer and fixed to each other by screwing to form a combined gong holder for the upper and lower gongs.

[0031] In this way, on the one hand the fixing of each gong to the gong holder is simplified thanks to the arrangement of one-piece heels as the gong fixing end, which avoids any brazing or welding operation of the base of the rod; on the other hand the mounting operations via a single gong holder for two gongs simultaneously, that is to say in this case the upper gong and the lower gong, via the combined gong holder, are simplified. There is thus only a single screwing operation required to connect the two gongs to the plate.

[0032] According to an even more preferred embodiment for implementing the invention, the two-tuning fork striking mechanism is characterized in that the upper gong stem and the lower gong stem are mounted on either side of the combined gong holder, and that the angle of the total angular sector of the upper gong is different from the angle of the total angular sector of the lower gong.

[0033] In this way, it is possible to easily produce a minute repeater type chime, each gong corresponding to a distinct note, with an improved sound thanks to an emulation of two cathedral gongs via the two new tuning fork gongs proposed, which would be superimposed on each other (i.e. the upper gong and the lower gong), without requiring substantial adjustments with regard to the positioning of the hammers, neither in height nor in terms of positioning on the plate, the two hammers being able to be arranged preferably close to the combined gong-holder on either side of the latter. The integration of such an improved striking mechanism on the plate is thus simplified.

[0034] According to an even more preferred embodiment for the striking mechanism of a wristwatch according to the invention, the predetermined position being located in an angular position at most 10 degrees beyond the top of the stem.

[0035] In this way, not only can the vibrations be transmitted very efficiently to the first branch on which the hammer acts, but also efficiently to the second branch via the nearby branch. Thus, the sound is optimally transmitted and distributed over both branches of the tuning fork.

[0036] According to a further preferred embodiment for the striking mechanism, the first branch and the second branch are arranged concentrically in the plane of the plate, the hammer is arranged to strike the first branch extending along the second arc of a circle arranged on the innermost concentric circle.

[0037] Such a configuration of the hammer and the tuning fork allows to optimize the transmission of vibrations on the two blades thanks to the hammer striking in the radial direction from the inside, thanks to the generation of a wave propagating towards the periphery of the plate also in the radial direction. Consequently, the sound produced from the tuning fork is optimal.

[0038] It will be understood from the remainder of this detailed description that the advantageous characteristics derived from the preferred embodiments may be taken in isolation or in combination, except when these are presented as mutually exclusive. Brief description of the drawings

[0039] Other advantageous characteristics will emerge more clearly from the following description of particular embodiments of the invention given by way of non-limiting example and represented by the appended drawings, in which: - there Figure 1is a three-dimensional exploded view of two tuning fork gongs used for the production of a striking mechanism according to a preferred embodiment of the invention, in which the two branches are arranged according to concentric arcs of circles, and the two gongs are mounted on the same gong holder, referred to as a combined gong holder; - the Figure 2 shows a three-dimensional top view of a striking mechanism using two tuning fork gongs according to an alternative embodiment of the invention, each gong having branches superimposed in height; - Finally, the Figure 3 shows a top and plan view of a tuning fork and a hammer forming part of a striking mechanism according to a preferred embodiment for carrying out the invention. Detailed description

[0040] There Figure 1illustrates a preferred embodiment of a striking mechanism 1 for a wristwatch using two tuning fork gongs 2 for producing a strike preferably of the minute repeater type, i.e. emitting two different notes, each associated with a particular tuning fork gong 2.

[0041] The view corresponding to the Figure 1is a three-dimensional exploded view of two tuning fork gongs 2 superimposed along a direction D perpendicular to the plane of the plate, the center of which is materialized by the letter O. The two tuning fork gongs 2 have in common that they each have a stem 21 which extends over a very restricted arc of a circle, of the order of 10 to 20 degrees at most, between a base 210 and a top 211, then are extended by two branches 22 extending over much more extended concentric arcs of a circle so as to extend the useful length of the blades as much as possible and emulate a blade whose total length would be close to double that of a simple blade wound around its entire circumference (that is to say a cathedral gong, extending over approximately two complete turns, or 720° - the branches of each of the tuning fork gongs represented here extending between approximately 540 and 660 degrees).It is at the level of the top 211 that the branch 220 is arranged, that is to say the place where the bifurcation corresponds between the two branches 22 of the tuning fork gong 2, here a first internal branch 22A, and a second branch 22B in the radial direction. This branch 220 preferably has a rounded shape to transmit the waves as harmoniously as possible for each of the tuning fork gongs 2. Since the two tuning fork gongs 2 are superimposed in height, that is to say in the direction D perpendicular to the plate, the following nomenclature is used to differentiate them: upper gong 2S for the tuning fork gong 2 located on top, and lower gong 2I for the one located below.

[0042] In the context of the invention, for reasons of symmetry, and therefore of the desired sound quality, each of the branches 22 of the tuning fork gong 2 extends exactly over the same angular sector, which is the reason why the free ends of each of them, that is to say in particular the first free end 221A of the first branch 22A and the second free end 221B of the second branch 22B of the lower gong 2I, stop at the level of the same radius R illustrated in dotted lines. The fact of choosing to arrange free ends for each of the branches - here the first free end 221A of the first branch 22A and the second free end 221B of the second branch 22B of each of the upper timbre 2S and lower timbre 2I also aims to improve the quality of the sound produced, as well as its duration, by attenuating the vibrations and oscillations generated on each of the branches 22 only to a minimum, and thus allowing them to be maintained for as long as possible.

[0043] For readability reasons, on the Figure 1 no hammer of the striking mechanism 1 has been shown, the arrangement of such a hammer and its interaction with the tuning fork gong 2 will be described later using the Figure 3 . There Figure 1focuses on the joint arrangement of the two tuning fork gongs, namely the upper gong 2S and the lower gong 2I, at the same fixing point on the plate. Usually, each gong of a striking mechanism is associated with a dedicated gong holder; according to the preferred embodiment described, each of the tuning fork gongs 2 has an integrated fixing heel, arranged at the base 210 of the stem 21 of the tuning fork gong 2. Thus, a first fixing heel 31 is arranged in a single piece in the extension of the base 210 of the stem of the upper gong 2S, and a second fixing heel 32 is also arranged in a single piece in the extension of the base 210 of the stem 21 of the lower gong 2I.The first heel 31 and the second fixing heel 32 are assembled to each other at the same fixing point to the plate to form a combined gong holder 3', that is to say a gong holder 3 carrying several gongs simultaneously, which facilitates the assembly operations and at the same time ensures a saving of space on the plate of the movement equipped with the striking mechanism 1. To soundproof the two tuning fork gongs 2, that is to say the upper gong 2S and the lower gong 2I, the two fixing heels, that is to say the first heel 31 and the second fixing heel 32 are separated by a spacer 33.To jointly assemble the upper stamp 2S and the lower stamp 2I to the plate, a first fixing hole 310A and a second fixing hole 310B are made in the first fixing heel 310, as well as similarly a first fixing hole 330A and a second fixing hole 330B in the spacer 33, and finally a first fixing hole 320A and a second fixing hole 320B in the second fixing heel 32, such that all of the first fixing holes and second fixing holes of each of the first heel 31, spacer 33 and respectively second heel are aligned respectively on the same screwing axis, and more precisely the first screwing axis T1 for the first holes (310A, 320A, 330A) and the second screwing axis T2 for the second holes (310B, 320B, 330B) of each of these parts to be assembled together and to the plate.

[0044] It may be noted that each of the first screw axis T1 and second screw axis T2 extend parallel to the direction D perpendicular to the plate, which implies that a slight spacing, at least equal to the thickness of the spacer 33, is provided in the direction of the height of the plate (i.e. the direction D) between the lower gong 2I and the upper gong 2D. Given that the vibrations are, according to this preferred embodiment, transmitted in the radial direction towards the outside by the hammers, this spacing may however be reduced to a minimum, on the one hand for reasons of space requirement in height on the plate, but also to require the least adjustments to the positioning of the hammers intended to strike each of the gongs.

[0045] On the Figure 1, it can be seen that the upper gong 2S extends in an anticlockwise direction, while the lower gong extends in a clockwise direction starting from the base 210 of the rod 21 of the tuning fork gong 2. This makes it possible to arrange the hammers striking each of the tuning fork gongs on either side of the combined gong holder 3'. Preferably, each of the tuning fork gongs 2 will extend over a different angular sector, so as to produce a different note; however, this could alternatively be achieved by adjusting the section of the rod 21 - which will be referred to below as the first section S1 - and that of the branches referred to as the second sections S2. According to the preferred embodiments illustrated, the first section S1 and second section S2 are square, constant, and identical.The fact that they are square not only facilitates their machining, but improves the quality of the vibrations thanks to the production of a fully symmetrical pattern on all its faces, and also allows the production of separate decorative patterns for each of the faces (for example via satin finishing, polyblocking, polishing, etc.) which thus makes it possible to improve in parallel the aesthetics of the gongs produced. The choice of an identity of section between the first section S1 of the rod 21 and the second section S2 of the branches makes it possible to emulate as best as possible an exact doubling of the useful length of a single-blade gong, and therefore to produce a virtual angular extension of the rod 21 by doubling via the branches 22, emulating as closely as possible the production of a cathedral gong, without the disadvantage of having to go back through an angular position where the gong holder would be located.

[0046] As can be seen on the Figure 1where the first section S1 of the rod 21 and the second section S2 of the first branch 22A and the second branch 22B are identical and consequently, this also applies to the first width L1 of the rod and the second width L2 of each of the branches 22. Given that the tuning fork 2 vibrates in the radial direction, a radial clearance between the first branch 22A arranged inwards and the second branch 22B arranged outwards will be chosen as being at least equal to this second width L2; more general considerations on the constraints to be considered and the preferred arrangement linked to this spacing between the branches 22 will be discussed in more detail on the basis of the Figure 3 .

[0047] In order to produce the tuning fork gongs 2 within the framework of the present invention, several materials are possible, in particular steel alloys such as 20AP steel or K720 steel with which acoustic tests have been carried out and shown to have particularly interesting, distinct performances compared to single-blade gongs.

[0048] There Figure 2 illustrates an alternative embodiment of a striking mechanism 1 for the invention, in which the two branches 22 of the tuning fork gong 2 are now arranged superimposed in the direction D perpendicular to the plate, and no longer in the radial direction. The two branches therefore extend along superimposed circular arcs in this direction D, and no longer concentric circular arcs in the radial direction as in the previous embodiment illustrated in the Figure 1, which allows for gaining thickness in the radial direction. The same philosophy of maximizing the useful length of the gong blades continues to apply, however, as for the previous embodiment. Indeed, we seek to obtain the largest possible ratio between the angular sectors associated with the rod 21 and those associated with the branches 22, here the first upper branch 22A and the second lower branch 22B. In other words, we seek to have a first angle α 1 corresponding to the first angular sector over which the first arc of a circle A1 of the rod 21 extends, as small as possible, and a second angle α 2 , corresponding to the second angular sector over which the second arc of a circle A2 of the first branch 22A extends, and the third arc of a circle A3 of the second branch 22B, which are identical and shown in dotted lines on the Figure 2 , as large as possible.

[0049] A difference with the first embodiment is however that the angle α 0 of the total angular sector of the tuning fork 2 with the equality (α 0 = α 1 + α 2 ) is limited compared to the previous embodiment, because it is around 180° rather than 360° of the previous embodiment.

[0050] In fact, instead of arranging two tuning fork gongs 2 in a superimposed manner in the context of the creation of a minute repeater type striking mechanism as on the Figure 1, it is possible to consider using two tuning fork gongs 2 arranged on either side of the same gong holder 3, but in the same horizontal plane, and to adjust the note by playing in particular on the angle α 0 of the total angular sector of the tuning fork gong 2 and the length of the branches, directly correlated to the angle α 2 , corresponding to the second angular sector. In such a case, however, the maximum angle of 360° no longer applies to a single tuning fork gong but to both, which are referenced here for the sake of clarity as corresponding to a left gong 2G and a right gong 2D. Consequently, the total useful length of the blades for the vibration of the sound is more limited.An advantage of this solution is however to be able to arrange the two hammers (not shown in this figure) in the same horizontal plane, or even to have this hammer strike directly on the rod 21 of the left gong 2G and the right gong 2D, on the one hand, and on the other hand to arrange both these two gongs (i.e. left gong 2G and right gong 2D) and the gong holder 3 in a single piece, via a single-piece body 30 which connects them together. In this way, both the machining and the assembly of the gongs to the plate are simplified; it is sufficient to make a first fixing hole 300A and a second fixing hole 300B in the single-piece body 300 and to fix the latter to the plate by screwing (NB: as in the . Figure 1 , for the sake of simplification, the fixing screws have not been shown in this figure either).

[0051] As for the previous embodiment, the first section S1 of the rod 21 and the second section S2 of the branches 22 of each of the tuning fork gongs 2, that is to say the first branch 22A and the second branch 22B of the left gong 2G and the right gong 2D, are square and identical, to best emulate the doubling of the useful length of the vibrating reeds and to best approximate a sound comparable to a cathedral gong. The same applies to the first width L1 of the rod 21 and the second width L2 of the branches 22 (that is to say the first branch 22A and the second branch 22B) of the tuning fork gong 2.However, since these branches 22 vibrate in the radial direction, the height spacing between these branches 22 does not theoretically necessarily need to be as large as the radial spacing; however, it can be seen that, schematically in this figure, it is equal to approximately the width of the branches (which is also equal to their thickness in the height direction corresponding to the direction D in the direction perpendicular to the plate) and of the rod - this width being equal to the first width L1 and the second width L2 respectively of the rod 21 and the branches, here again preferably identical.

[0052] There Figure 3 shows a tuning fork timbre produced according to a preferred embodiment for the invention corresponding to that of the Figure 1, and which would be integrated into a striking mechanism 1 of which a hammer is shown to indicate how it interacts with the tuning fork gong 2. Since this is a top view, it thus highlights the plane (P) of the plate and its center O, which also constitutes the center of symmetry of the tuning fork gong 2.

[0053] The tuning fork 2 of the Figure 3 corresponds to the upper stamp 2S of the Figure 1 in terms of the useful length of the blades, which will however be explained in more detail here. We can distinguish, in the extension of the base 210 of the rod 21 of the tuning fork gong 2, the gong holder 3 which is not described generically here because it is not possible to distinguish the lower tuning fork gong 2I below, as on the Figure 1; it may however be considered that this tuning fork gong 2 comprises a first integrated fixing heel 31, that is to say arranged in a single piece with the tuning fork gong 2 itself. This first fixing heel 31 is similarly provided with a first fixing hole 310A and a second fixing hole 310B, each threaded and intended to receive screws for fixing to the plate.

[0054] As explained above, the "total" length of the tuning fork in terms of the useful length of the blades is determined by the angle α 0 of the total angular sector of the tuning fork 2 and the radius of each of the branches, i.e. the first branch 22A arranged here inward in the radial direction and the second branch 22B arranged outward in the radial direction. The angle α 0 is equal to the sum of the first angle α 1 corresponding to the first angular sector over which the first arc of a circle A1 of the rod 21 extends, and of the second angle α 2 corresponding to the second angular sector over which the second arc of a circle A2 of the first branch 22A extends, and the third arc of a circle A3 of the second branch 22B [α 2 being identical for the angular sectors corresponding to A2 and A3, which extend along concentric arcs of circles and are here again illustrated in dotted lines].We thus seek to minimize the first angle α 1 and keep it at the strict minimum, i.e. around 10°, and to limit the first angular sector to a maximum of 20°, while on the contrary we seek to maximize the second angle α 2 so that it reaches at least 300°, and if possible 320° or even more, the only constraint then being that the angle α 0 , which is less than 360°, leaves enough space despite everything to arrange the gong holder 3. Since the vibration takes place, according to the illustrated embodiment, in the radial direction, we can start from the principle that an angular sector of 20° will be sufficient to arrange the gong holder in order to maximize the useful length of the doubled blades of the tuning fork gong and to get as close as possible to a “cathedral” configuration in terms of winding length. According to the embodiment of the . Figure 3, the first angle α 1 is thus approximately 10°, the second angle α 2 approximately 315° and the angle α 0 therefore approximately 320°.

[0055] Since the tuning fork 2 shown on the Figure 3 conforms to the upper stamp 2S of the Figure 1, it can be seen that the ends of each of the branches, that is to say the first end 221A of the first branch 22A and the second end 221B of the second branch 22B are free in order to maximize the vibration time, and that the first section S1 of the rod 21 and the second section S2 of the branches are identical and square, and consequently the first width L1 and the second width L2 also. It can however be noted that the spacing E which is here radial between the first branch 22A and the second branch 22B is substantially also at a width corresponding to the first width L1 and the second width L2.More generally, it may be considered that it is desirable to have a spacing E between the branches 22 which is at least equal to the first width L1 of the rod 21, so that the second and third arcs of circles A2, A3 along which they extend do not radially overlap the extension of the first arc of circle A1 corresponding to the rod following the second angular sector. In this way, the two branches can vibrate radially without any risk of touching each other, or even of generating too marked interference.However, in order to minimize the radial size, we will seek to limit the value of this spacing E to less than twice this first width L1 (in other words: E<2*L1) and, if the second width L2 is less than the first width L1, but not less than half of the latter, which is common in terms of proportions between a rod and branches of tuning forks, to keep this spacing preferably less than twice this second width L2 (that is to say E<2*L2). On the . Figure 3, the configuration is such that the extension of the rod would be almost sandwiched between the first branch 22A and the second branch 22B, the spacing E being preferably equal to 0.8mm and the width of each of these branches (L=L1=L2) of 0.6mm. Such a configuration makes it possible to place the tuning fork 2 in the plane of the plate (P) in a peripheral ring of approximately 2mm thickness in the radial direction (2*0.6 for the thickness of each branch and 0.8 for their mutual spacing). According to the configuration shown in the Figure 1 , for example, we have an internal radius Ri of 16 mm at the level of the interior of the first branch 22A and an external radius Re of 18 mm at the level of the exterior of the second branch 22B to accommodate the proposed tuning fork gong 2.

[0056] As illustrated on the Figure 3, the hammer 4 is arranged close to the gong holder 3, and is rotatably mounted around a pivot axis 40 arranged relatively close to the base 210 of the stem 21 of the tuning fork gong 2. At its distal end, the hammer 4, which here has a substantially seahorse shape, is provided with a striking tip 41 acting radially on the first branch 22A of the tuning fork gong 2 with a predetermined force depending on the desired sound intensity, but also taking into account the constraints in terms of rebound of the hammer 4. A particularly interesting position has been identified close to the top 211 of the stem 21, and therefore of the branch 220, because this makes it possible to transmit the vibrations of the first branch 22A indirectly to the second branch 22B as well as possible, while at the same time minimizing the rebound of the hammer 4.Thus the predetermined striking position Pm of the hammer 4 is located at a third angle α 3 less than or equal to 25° relative to the base of the rod 21 of the tuning fork, which corresponds parallel to an angular position at most 10° to 15° away from the top of the rod 21 when the latter extends over a first arc of a circle of a first angle α 1 between 10° and 15°.

[0057] The tuning fork gong 2 and the striking mechanism 1 proposed within the framework of the invention therefore make it possible to significantly improve the sound qualities by approaching the properties of cathedral gongs without, however, being confronted with the disadvantages in terms of mounting and arrangement on the plate.

[0058] Although the invention has been explained using the embodiments illustrated in the figures described above, those skilled in the art will nevertheless understand that other variants are possible for its implementation without departing from the scope of the invention, in particular in terms of the section of the rods and branches of the tuning fork to be produced, provided that the symmetry properties are preserved as best as possible in order to guarantee the best possible transmission of the waves within the vibrating element that it forms, as well as the arrangement of the direction of actuation of the hammers.

Claims

1. Tuning fork gong (2) for striking mechanism (1) of a wristwatch, characterized in thatit comprises a fixing rod (21) extending along a first arc of a circle (A1) from a base (210) to a vertex (211) on a first angular sector, said fixing rod (21) being extended by a first branch (22A) extending along a second arc of a circle (A2) and a second branch (22B) extending along a third arc of a circle (A3), said second and third arcs of a circle (A2, A3) being formed on concentric circles in the plane of the plate (P) or circles superimposed in a direction (D) perpendicular to said plane of the plate (P), said first branch (22A) and said second branch (22B) also extending over a second identical angular sector, said tuning fork (1) extending, in its entirety,on a total angular sector of angle (α0) strictly less than 360 degrees equal to the sum of a first angle (α1) corresponding to said first angular sector and a second angle (α2) corresponding to said second angular sector., 2. Tuning fork gong (2) for striking mechanism (1) of a wristwatch, characterized in that said first angle (α1) of said first angular sector is less than said second angle (α2) of said second angular sector.

3. Tuning fork gong (2) for striking mechanism (1) of a wristwatch according to one of the preceding claims, in which the bifurcation between said fixing rod (21) and said branches (22) at said top (211) of said rod (21) is effected via a branch (220) having a rounded shape.

4. Tuning fork gong (2) for a striking mechanism (1) of a wristwatch according to one of the preceding claims, characterized in thatsaid first angle (α1) corresponding to the first angular sector is between 10 and 20 degrees, and that said second angle (α2) corresponding to said second angular sector is between 300 and 320 degrees.

5. Tuning fork gong (2) for a striking mechanism (1) of a wristwatch according to one of the preceding claims, characterized in that said first branch (22A) and said second branch (22B) are arranged concentrically in said plane of the plate (P).

6. Tuning fork gong (2) for a striking mechanism (1) of a wristwatch according to one of claims 1 to 4, characterized in that said first branch (22A) and said second branch (22B) are superimposed on each other in a direction (D) perpendicular to said plane of the plate (P).

7. Tuning fork gong (2) for a striking mechanism (1) of a wristwatch according to one of the preceding claims, characterized in thatsaid fixing rod (210) has a constant first section (S1), and said first branch (22A) and said second branch (22B) have the same constant second section (S2).

8. Tuning fork gong (2) for a striking mechanism (1) of a wristwatch according to claim 7, characterized in that said first section (S1) and second section (S2) are square and identical.

9. Tuning fork gong (2) for a striking mechanism (1) of a wristwatch according to one of claims 7 or 8, wherein said first branch (22A) and said second branch (22B) are spaced apart by a spacing (E) greater than the first width (L1) of said first section (S1).

10. Striking mechanism (1) of a wristwatch comprising a tuning fork gong (2) according to one of the preceding claims 1 to 9, and further comprising a hammer (4) pivoting about a pivot axis (40) and which is arranged to strike said tuning fork gong (1) in a predetermined position (Pm) on one of the branches (22) chosen from said first branch (22A) and said second branch (22B).

11. Striking mechanism (1) of a wristwatch according to claim 10 comprising a tuning fork gong (2) characterized in that said base (210) of said fixing rod (21) is fixed to a stamp holder (3), but that the first end (221A) of said first branch (22A) as well as the second end (221B) of said second branch (22B) are free.

12. Striking mechanism (1) of a wristwatch according to claim 10 or 11, comprising two said tuning fork gongs (2) formed respectively by an upper gong (2S) and a lower gong (2I), said base (210) of said stem (21) of said upper gong (2S) being extended in a single piece by a first fixing heel (31) and said base (210) of said stem (21) of said lower gong (2I) being extended in a single piece by a second fixing heel (32), said first fixing heel (31) and said second fixing heel (32) being separated by a spacer (33) and fixed to each other by screwing to form a combined gong holder (3') of said upper gong (2S) and lower gong (2I).

13. Striking mechanism (1) of a wristwatch according to claim 12, characterized in thatthe rod (21) of said upper stamp (2S) and the rod (21) of said lower stamp (2I) are mounted on either side of the combined stamp holder (3'), and that the angle (α0) of the total angular sector of said upper stamp (2S) is different from the angle (α0) of the total angular sector of said lower stamp (2I).

14. Striking mechanism (1) comprising a tuning fork gong (2) according to claim 10 to 13, said predetermined position (Pm) being located in an angular position at most 10 degrees beyond said top (211) of said stem (21).

15. Striking mechanism (1) comprising a tuning fork gong (2) according to one of claims 10 to 14, said first branch (22A) and said second branch (22B) being arranged concentrically in the plane of the plate (P), said hammer (40) being arranged to strike said first branch (22A) extending along said second arc of a circle (A2) arranged on the innermost concentric circle.

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