Timepiece movement comprising a time striking mechanism provided with flexible guides

Abstract

The invention relates to a timepiece movement comprising a striking mechanism (10) of a watch, said striking mechanism (10) comprising a vibrating element (11) and a striking device (120) for striking said vibrating element (11), said striking device (120) comprising a hammer (121) fastened in a cantilevered manner to a structural element of the timepiece movement by means of a strip (122) forming a flexible guide, said strip (122) being arranged so as to extend along directions intersecting at a point C, which is materialized by a center of instantaneous rotation arranged along an axis T, which is tangent to the vibrating element (11).

Description

Technical Field

[0001] This invention relates to the field of complex functions in watch movements, and in particular to the striking mechanism of a watch.

[0002] More specifically, the present invention relates to a watch movement including a striking mechanism with flexible guides.

[0003] This timekeeping mechanism can be adapted to any type of timekeeping, such as minute repeater, repeater, grand chime, small chime, or alarm clock. Background Technology

[0004] The striking mechanism of a known watch includes a hammer designed to strike a vibrating element (e.g., a gong).

[0005] In particular, the hammer is spring-bound to move toward the vibrating element and is flipped up by an activation mechanism (such as a lifting element or another dedicated mechanism), that is, kept away from the reed.

[0006] Typically, the vibrating element extends along a curved direction within the watch case, for example, around the central axis of the case. When the hammer strikes the vibrating element, the hammer generates a force on the vibrating element that causes it to vibrate, thus producing a ringing sound. These forces include normal and tangential components, with the tangential component characterizing the friction of the hammer on the vibrating element.

[0007] In particular, the vibration of the vibrating element is basically generated by the normal component of the force applied by the hammer, so it is necessary to control and maximize this normal component in order to control the impact of the hammer on the vibrating element and the effectiveness of the sound generated by the impact. Summary of the Invention

[0008] To address these deficiencies, the present invention provides a watch movement comprising a striking mechanism, the striking mechanism including a vibrating element and a striking device for striking the vibrating element. The striking device includes a hammer, which is cantilevered to a structural member of the watch movement via at least two elastic strips forming flexible guides. The two strips are arranged to extend along a direction intersecting at point C, which is arranged along an axis T tangent to the vibrating element at a point intended to receive the strike of the hammer. The hammer is driven to move in a direction D perpendicular to the axis T, or in a direction tangent to the direction D perpendicular to the axis T.

[0009] In certain embodiments, the invention may be considered individually or, according to any technically feasible combination, further include one or more of the following features.

[0010] In a particular embodiment, the striking device includes at least one elastic strip arranged such that its direction of extension does not pass through point C.

[0011] In a particular embodiment, the striking device includes a plurality of elastic strips arranged to form a plurality of strip groups, wherein in each strip group the elastic strips extend in a direction that intersects at a point along the axis T, and the intersection points of the directions of the elastic strips in each strip group are different from each other.

[0012] In a particular embodiment, the striking device is fastened to the structural component of the watch movement only by means of an inlay-type mechanical connection.

[0013] In a particular embodiment, at least the elastic strip is made of silicon by deep reactive ion etching.

[0014] In certain embodiments, at least the elastic strip is made by laser processing, particularly by femtosecond laser processing, or by electrical discharge machining.

[0015] In a particular embodiment, the striking device is an integral unit.

[0016] In a particular embodiment, the striking device is made of amorphous metal by molding or thermoforming.

[0017] In a particular embodiment, the striking device is made of nickel or a nickel-phosphorus alloy by the LIGA method.

[0018] In a particular embodiment, the thickness of the elastic strip is smaller than the thickness of the hammer. Attached Figure Description

[0019] Other features and advantages of the invention will become apparent after reading the following detailed description, given as a non-limiting example, with reference to the accompanying drawings, in which:

[0020] - Figure 1 A schematic top view of a time-telling mechanism according to a preferred embodiment of the present invention is shown, the time-telling mechanism including a striking device in a resting state;

[0021] - Figure 2 A schematic top view of a time-telling mechanism according to another embodiment of the present invention is shown, the time-telling mechanism including a striking device in a resting state;

[0022] - Figure 3 schematically shown Figure 1 or Figure 2 A cross-sectional view of the striking device of the timekeeping mechanism.

[0023] It should be noted that, for clarity, the accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0024] Figure 1 The striking mechanism 10 of the watch movement in a preferred embodiment of the invention is shown.

[0025] The striking mechanism 10 includes a vibrating element 11 and a striking device 120 designed to strike the vibrating element 11 to produce sound. The vibrating element 11 is fastened to a structural component of the watch movement, such as to a bridge plate, a mainplate, etc. Figure 1 In the example of the embodiment shown, the vibrating element 11 is formed of a reed.

[0026] The striking device 120 includes a hammer 121, which is cantilevered to the structural components of the watch movement by multiple strips 122 forming flexible guides. The strips 122 are capable of elastic deformation and are used in this invention to guide and drive the hammer 121. Preferably, there are two strips 122. In particular, when the striking device 120 is in a resting state, that is, in a balanced position, each strip 122 has a straight shape. The flexible guides formed by the strips 122 are of the telecentric compliant (RCC) type.

[0027] In short, the striking device 120 is raised in a manner known to those skilled in the art via an activation mechanism (not shown in the drawings), such as a lifting member or any other dedicated mechanism. That is, the hammer 121 is driven away from the vibrating element 11 to force the strip 122 to gradually deform until it reaches the raised state. Next, the activation mechanism releases the hammer 121 in response to the elapsed time of the current hour or according to a user instruction. The hammer 121 is then driven by the elastic restoring force of the strip 122 to strike the vibrating element 11, thus placing the striking device 120 in the striking state.

[0028] Advantageously, compared to conventional watch pivots, the strip 122 allows for very precise positioning of the hammer 121 relative to the watch movement's structural components, and especially relative to the vibrating element 11, without mechanical clearance or any lubrication. Furthermore, the strip 122 provides a constant amount of energy to move the hammer 121 each time the striking device 120 strikes the vibrating element 11.

[0029] like Figures 1 to 3 As schematically shown, the strip 122 extends between two longitudinal ends. Thus, each strip 122 is mechanically connected to the structural member of the watch movement via one of its longitudinal ends and to the hammer 121 via its other longitudinal end. In other words, the striking device 120 is fastened to the structural member of the watch movement only by an inlay-type mechanical connection; that is, the strip 122 constitutes the only mechanical connection between the hammer 121 and the structural member.

[0030] In particular, each strip 122 can be fastened to the structural components of the watch movement by welding, threading, bonding, tight fitting, or any other suitable means within the scope of those skilled in the art.

[0031] Strips 122 are arranged to extend along directions intersecting at point C, which is specifically defined as the instantaneous rotation center arranged along axis T, which is tangent to the vibrating element 11, as shown below. Figure 1 As shown. More specifically, the axis T is tangent to the vibrating element 11 at the point where it is intended to withstand the impact of the hammer 121 (i.e., at the point of impact of the hammer 121), as shown. Therefore, the hammer 121 is driven to move in a direction D perpendicular to the axis T, or in a direction tangent to the direction D perpendicular to the axis T.

[0032] This feature has many advantages.

[0033] In effect, this feature allows for maximizing the normal component of the force exerted on the vibrating element 11 by the hammer 121 upon impact, and potentially eliminating any tangential component. Therefore, for a given elastic characteristic of the strip 122, the impact is more efficient in terms of the force transmitted to the vibrating element 11, resulting in a higher volume generated by the impact.

[0034] Furthermore, this feature allows for better control over the position of the striking point of the hammer 121 on the surface of the vibrating element 11, and thus better control over the vibration response of the vibrating element 11, and consequently, better control over the sound effect produced upon impact. More specifically, the sound effect produced upon impact varies depending on whether the striking point is located on the antinode or node of the vibration wave pattern of the vibrating element 11.

[0035] Finally, the use of the flexible guide and its specific arrangement enable the volume of the striking device 120 to be reduced and the number of parts forming the striking device to be greatly reduced, since the flexible guide functions as both a pivot and an elastic return function.

[0036] It should be noted that the striking device 120 may include at least two elastic strips 122 arranged to extend in a direction that intersects at the same point C along the axis T. This feature allows for an increase in the impact force of the hammer 121 on the vibrating element for a given stroke.

[0037] Alternatively or additionally, at least one strip 122 may be arranged such that its direction of extension does not pass through point C. In particular, as... Figure 2As shown, it can be envisioned that the striking device 120 includes multiple strips 122 arranged to form multiple strip groups. In each strip group, the strips 122 extend in directions that intersect at a point along the axis T, and the intersection points of the directions of the strips 122 in each strip group are different from each other. This feature allows for an increase in the stroke of the hammer 121.

[0038] Preferably, the striking device 120 is a single piece. Therefore, the striking device 120 is particularly simple to manufacture, and its manufacturing cost is limited. Furthermore, the mechanism is unlikely to suffer a reduction in power upon impact related to potential mechanical backlash, which would exist if the striking device 120 were designed by assembling various parts.

[0039] In particular, the striking device 120 can be made of an amorphous metal, for example, formed by molding or hot forming of nickel or nickel-phosphorus alloys, for example by the LIGA method.

[0040] Alternatively, the striking device 120, especially the strip 122, can be made of silicon, for example by dry etching, especially by deep reactive ion etching (DRIE, a method of fabrication known to those skilled in the art). Alternatively, the strip 122 can be made of steel by laser processing (especially by femtosecond laser) or by electrical discharge machining.

[0041] In particular, the hammer 121 may include one or more mass blocks made of a metallic material, such as tungsten or steel, and the strip 122 is fastened to the mass blocks by pressing, gluing, screwing or pinning.

[0042] Advantageously, the thickness of strip 122 is smaller than the thickness of hammer 121, for example, as Figure 3 A schematic cross-sectional view is shown. This feature allows the weight of the hammer 121 to be increased relative to the weight of the strip 122, and thus increases the energy provided by the strip 122 when striking the vibrating element 11.

[0043] It should be noted that the thickness is defined as the dimension extending along a direction perpendicular to the plane in which the striking device 120 and the vibrating element 11 can move.

[0044] More generally, it should be noted that the implementation methods and embodiments considered above have been described as non-limiting examples, and therefore other variations may also be considered.

[0045] In particular, the sound hammer in Figure 1 and Figure 2 The illustrated embodiment has a trapezoidal shape, but it can have any shape suitable for achieving the strike.

[0046] In addition, Figure 1 and Figure 2 In the illustrated embodiment, the vibrating element 11 is formed of a reed, which includes a strip extending in a circular direction, and the striking device 120 is disposed inside the strip. Alternatively, the striking device 120 may be disposed outside the strip of the reed.

[0047] Furthermore, the vibrating element 11 can be any suitable shape that enables it to vibrate after being struck by the hammer and to produce sound when vibrating, such as a bell or a reed.

Claims

1. A watch movement comprising a striking mechanism (10) of a watch, the striking mechanism (10) comprising a vibrating element (11) and a striking device (120) for striking the vibrating element (11), the striking device (120) comprising a hammer (121) the hammer (121) being cantilevered to a structural member of the watch movement by at least two elastic strips (122) forming a flexible guide, the striking mechanism (10) being characterized in that the at least two elastic strips (122) are arranged to extend along a direction intersecting at a point C, the point C being arranged along an axis T, the axis T being tangent to the vibrating element (11) at a point intended to receive the strike of the hammer (121), the hammer (121) being driven to move in a direction D perpendicular to the axis T, or in a direction tangent to the direction D perpendicular to the axis T.

2. The watch movement according to claim 1, wherein, The striking device (120) includes at least one additional elastic strip (122) arranged such that its direction of extension does not pass through the point C.

3. The watch movement according to claim 2, wherein, The striking device (120) includes a plurality of elastic strips (122) arranged to form a plurality of strip groups. In each strip group, the elastic strips (122) extend in a direction that intersects at the intersection point on the axis T. The intersection points of the directions of the elastic strips (122) in each strip group are different from each other.

4. The watch movement according to any one of claims 1 to 3, wherein, The striking device (120) is fastened to the structural component of the watch movement only by an inlay-type mechanical connection.

5. The watch movement according to any one of claims 1 to 3, wherein, At least the elastic strip (122) is made of silicon by deep reactive ion etching.

6. The watch movement according to any one of claims 1 to 3, wherein, At least the elastic strip (122) is made by laser processing or by electrical discharge machining.

7. The watch movement according to any one of claims 1 to 3, wherein, At least the elastic strip (122) is made by femtosecond laser.

8. The watch movement according to any one of claims 1 to 3, wherein, The striking device (120) is an integral unit.

9. The watch movement according to claim 8, wherein, The striking device (120) is made of amorphous metal by molding or thermoforming.

10. The watch movement according to claim 8, wherein, The striking device (120) is made of nickel or a nickel-phosphorus alloy by the LIGA method.

11. The watch movement according to any one of claims 1 to 3, wherein, The thickness of the elastic strip (122) is smaller than the thickness of the hammer (121).

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