Timepiece movement comprising a striking mechanism provided with a flexure

Abstract

The invention relates to a watch movement comprising a striking mechanism (10) of a watch having a vibrating element (11) and a striking device (120) of said vibrating element (11) comprising a hammer (121) fixed in cantilever to a structure of the watch movement by means of blades of a flexible guide (122), said blades (122) being arranged both so as to extend in intersecting directions to a point materializing an instantaneous center of rotation C disposed on an axis T tangent to the vibrating element (11).

Description

Technical field of the invention

[0001] The invention falls within the field of watch movement complications, and in particular the striking mechanisms of a watch.

[0002] More specifically, the invention relates to a watch movement comprising a striking mechanism with a flexible guide.

[0003] Such a ringing mechanism can be adapted to any type of ringing, such as a quarter repeater, minute repeater, loud ring, small ring or alarm. Technological background

[0004] Watch striking mechanisms are known to include a hammer designed to strike a vibrating element, such as a gong.

[0005] In particular, the hammer is constrained in movement towards the vibrating element by a spring and is cocked, that is to say held away from the gong, by an activation mechanism, such as a lift or other dedicated mechanism.

[0006] Generally, the vibrating element extends along a curvilinear direction within the watch case, for example, around a central axis. When the hammer strikes the vibrating element, it generates forces that cause it to vibrate and, consequently, produce the chime. These forces have a normal component and a tangential component, the latter characterizing the friction of the hammer on the vibrating element.

[0007] In particular, the vibration of the vibrating element is essentially generated by the normal component of the forces applied by the hammer, hence the need to control and maximize this normal component to control the effectiveness of the impact of the hammer on the vibrating element and the sound produced by this impact.

[0008] Document CH 715 617 A2 discloses a bell hammer suspended on two flexible blades. Summary of the invention

[0009] The invention overcomes the aforementioned drawbacks by proposing, for this purpose, a watch movement comprising a striking mechanism for a watch including a vibrating element and a striking device for said vibrating element. The striking device comprises a hammer cantilevered from a structure of the watch movement by means of at least two elastic blades forming a flexible guide. The two blades are arranged so as to extend in intersecting directions at a point C located on an axis T tangent to the vibrating element, the axis T being tangent to a surface of the vibrating element intended to be struck by the hammer of the striking device.

[0010] In particular embodiments, the invention may further comprise one or more of the following features, taken individually or in all technically possible combinations.

[0011] In particular embodiments, the striking device includes at least one elastic blade arranged so that the direction in which it extends does not pass through point C.

[0012] In particular embodiments, the striking device comprises blades arranged so as to form several groups of blades in each of which the blades extend in secant directions to a point of intersection on the axis T, said points of intersection of the directions of the blades of each group being distinct from one another.

[0013] In particular embodiments, the striking device is fixed to the structure of the watch movement only by a mechanical connection of the embedment type.

[0014] In particular embodiments, at least the blades are made of silicon, by deep reactive ion etching.

[0015] In particular embodiments, at least the blades are produced by laser machining, in particular by femtosecond lasers, or by electro-erosion.

[0016] In particular embodiments, the striking device is a single unit.

[0017] In particular embodiments, the striking device is made of amorphous metal, by molding or by hot forming.

[0018] In particular embodiments, the striking device is made of nickel or nickel phosphorus, by LIGA process.

[0019] In particular embodiments, the blades have a thickness less than that of the hammer. Brief description of the figures

[0020] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example, with reference to the accompanying drawings in which: there figure 1 schematically represents a top view of a bell mechanism comprising a striking device in a resting state, according to a preferred embodiment of the invention; figure 2 schematically represents a top view of a bell mechanism comprising a striking device in a resting state, according to another embodiment of the invention; the figure 3 schematically represents a cross-sectional view of the striking device of the bell mechanism of the figure 1 or 2 .

[0021] Note that the figures are not necessarily drawn to scale for reasons of clarity. Detailed description of the invention

[0022] There figure 1 shows a striking mechanism 10 of a watch movement in a preferred embodiment of the invention.

[0023] The striking mechanism 10 comprises a vibrating element 11 and a striking device 120 for striking said vibrating element 11 to produce a sound. The vibrating element 11 is fixed to a structure of the watch movement, for example to a bridge, a plate, etc., and is, in the embodiment shown in the figure 1 formed by a stamp.

[0024] The striking device 120 comprises a hammer 121 cantilevered from the watch movement structure by means of several blades 122 forming a flexible guide. The blades 122 exhibit elastic deformation and are used in the present invention for guiding and driving the hammer 121. Preferably, there are two blades 122. In particular, each blade 122 has a straight shape when the striking device 120 is at rest, i.e., in an equilibrium position. The flexible guide formed by the blades 122 is of the remote center of rotation (RCC) type.

[0025] In summary, as is known to those skilled in the art, the striking device 120 is cocked by an activation mechanism (not shown in the figures), such as a lever or other dedicated mechanism. This means that the hammer 121 is driven away from the vibrating element 11, causing the blades 122 to deform progressively until they reach a cocked state. Subsequently, in response to the passage of a predefined time value or upon instruction from a user, the activation mechanism releases the hammer 121, which is then, under the effect of the elastic return force of the blades 122, driven to strike the vibrating element 11, the striking device 120 being in a striking state.

[0026] Advantageously, the blades 122 allow for very precise positioning of the hammer 121 relative to the structure of the watch movement, and in particular relative to the vibrating element 11, without mechanical play or lubrication, unlike a conventional watch pivot. Furthermore, the blades 122 provide a constant amount of energy to move the hammer 121 with each strike of the striking device 120 on the vibrating element 11.

[0027] As schematically shown figures 1 to 3The blades 122 extend between two longitudinal ends. Each blade 122 is therefore mechanically linked, by one of its longitudinal ends, to the structure of the watch movement, and by its other longitudinal end, to the hammer 121. In other words, the striking device 120 is fixed to the structure of the watch movement only by a mechanical connection of the fixed type, that is to say that the blades 122 constitute the only mechanical connection between the hammer 121 and the structure.

[0028] In particular, each 122 blade can be fixed to the structure of the watch movement by welding, screwing, gluing, tight fitting, or by any other means suitable to the reach of a person skilled in the art.

[0029] The blades 122 are arranged so that they extend in intersecting directions to a point C, which represents an instantaneous center of rotation located on an axis T tangent to the vibrating element 11, as shown in the figure 1More precisely, the axis T is tangent to a surface of the vibrating element 11 intended to be subjected to the impact of the hammer 121. Thus, the hammer is driven in displacement along a direction D perpendicular to the axis T, or along a direction tangent to a direction D perpendicular to the axis T.

[0030] This feature offers several advantages.

[0031] Indeed, this feature maximizes the normal component of the forces applied by the hammer 121 to the vibrating element 11 during percussion, even eliminating any tangential component. Thus, percussion is more efficient in terms of the forces transmitted to the vibrating element 11 for given elastic characteristics of the blades 122, resulting in a higher sound volume produced by said percussion.

[0032] Furthermore, this feature allows for better control of the position of the hammer's striking point 121 on the surface of the vibrating element 11, and thus enables better control of the vibratory response of said vibrating element 11 and therefore of the sound produced during the impact. More precisely, the sound produced during the impact differs depending on whether the striking point is located on a node or on an antinode of vibration of a vibratory mode of the vibrating element 11.

[0033] Finally, the use of a flexible guide and its particular arrangement makes it possible to reduce the size of the striking device 120 and to considerably reduce the number of parts constituting said device, insofar as said flexible guide plays both a pivot role and an elastic return role.

[0034] It should be noted that the striking device 120 may include more than two elastic blades 122 arranged so as to extend in intersecting directions at the same point C on the axis T. This feature makes it possible to increase the impact force of the hammer 121 on the vibrating element, for a given stroke.

[0035] Alternatively or in addition, at least one blade 122 can be arranged so that the direction in which it extends does not pass through point C. In particular, as shown by the figure 2 It is conceivable that the striking device 120 comprises blades 122 arranged to form several groups of blades 122, in each of which the blades 122 extend along intersecting directions at a point of intersection on the axis T, the points of intersection of the directions of the blades 122 in each group being distinct from one another. This feature makes it possible to increase the stroke of the hammer 121.

[0036] Preferably, the 120 striking device is a single unit. This makes the 120 striking device particularly simple to manufacture, and its production cost is kept down. Furthermore, the mechanism is not susceptible to power loss during percussion due to any mechanical play that might exist if the 120 striking device were constructed by assembling various parts.

[0037] In particular, the 120 striking device can be made of amorphous metal, for example by molding or hot forming, or of nickel or nickel phosphorus, for example by LIGA process.

[0038] Alternatively, the striking device 120, and in particular the blades 122, can be made of silicon, for example by dry etching, and more particularly by deep reactive ion etching, a manufacturing method known as such to those skilled in the art under the acronym DRIE meaning Deep Rectified Ion Etchingin English. The 122 blades can, alternatively, be made of steel, and formed by laser machining, in particular by femtosecond laser, or by electro-erosion.

[0039] In particular, the hammer 121 may include one or more masses made of a metallic material, for example tungsten or steel, to which the blades 122 are attached by pressing, gluing, screw or pin.

[0040] Advantageously, the blades 122 have a thinner profile than the hammer 121, as can be seen in the schematic cross-sectional view of the figure 3 This feature makes it possible to increase the mass of the hammer 121 relative to that of the blades 122, and therefore to increase the energy supplied by the latter during the percussion against the vibrating element 11.

[0041] It should be noted that the thickness is defined as the dimension extending in a direction perpendicular to a plane in which the striking device 120 and the vibrating element 11 are mobile.

[0042] More generally, it should be noted that the implementation and realization methods considered above have been described as non-limiting examples, and that other variants are therefore conceivable.

[0043] In particular, the hammer has a trapezoidal shape in the examples of its realization shown on the figures 1 and 2 , but it can alternatively take any form suitable for the performance of percussion.

[0044] Furthermore, in the implementation examples shown on the figures 1 and 2, the vibrating element 11 is formed by a stamp comprising a strand extending in a circular direction inside which the striking device 120 is arranged. Alternatively, the striking device 120 could be arranged outside the strand of the stamp.

[0045] Furthermore, the vibrating element 11 can adopt any suitable shape enabling it to vibrate following a hammer strike and to generate a sound by vibrating, such as a bell or a gong.

Claims

1. Horological movement comprising a striking mechanism (10) of a watch comprising a vibrating element (11) and a striking device (120) of said vibrating element (11) comprising a hammer (121) fixed overhanging a structure of the horological movement by means of at least two elastic strips (122) forming a flexible guide, in which said strips (122) are both arranged so as to extend in directions intersecting at a point C disposed along an axis T tangent to the vibrating element (11), characterised in that the axis T is tangent to a surface of the vibrating element (11) intended to be subjected to the impact of the hammer (121).

2. Horological movement according to claim 1, wherein the striking device (120) includes at least one elastic strip (122) arranged so that the direction in which it extends does not pass through the point C.

3. Horological movement according to claim 2, wherein the striking device (120) includes strips (122) arranged so as to form a plurality of groups of strips (122) in each of which the strips (122) extend in directions intersecting at an intersection point along the axis T, said intersection points of the directions of the strips (122) of each group being different from one another.

4. Horological movement according to claims 1 to 3, wherein the striking device (120) is fixed to the structure of the horological movement only by a mechanical connection of the setting type.

5. Horological movement according to one of claims 1 to 4, wherein at least the strips (122) are made of silicon, by deep reactive ion etching.

6. Horological movement according to one of claims 1 to 4, wherein at least the strips (122) are made by laser machining, in particular by femtosecond laser, or by electroerosion.

7. Horological movement according to one of claims 1 to 6, wherein the striking device (120) is one piece.

8. Horological movement according to claim 7, wherein the striking device (120) is made of amorphous metal, by moulding or by hot forming.

9. Horological movement according to claim 7, wherein the striking device (120) is made of nickel or of phosphorus nickel, by a LIGA method.

10. Horological movement according to claims 1 to 9, wherein the strips (122) have a thickness thinner than that of the hammer (121).

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