CH719907A2 - Watch movement including a striking mechanism with flexible guidance. - Google Patents

Abstract

The invention relates to a watch 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 in the door to false to a structure of the watch movement via blades of a flexible guide (122), said blades (122) being arranged one and the other so as to extend in intersecting directions at a point materializing an instantaneous center of rotation C arranged on an axis T tangent to the vibrating element (11).

Description

Technical field of the invention

[0001] The invention relates to the field of watch movement complications, and in particular watch striking mechanisms.

[0002] More particularly, the invention relates to a watch movement comprising a striking mechanism provided with flexible guidance.

[0003] Such a striking mechanism can be adapted to any type of striking, such as a repeat of quarters, minutes, a grand strike, a small strike or an alarm.

Technology background

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

[0005] In particular, the hammer is forced to move towards the vibrating element by a spring and is armed, that is to say kept at a distance from the gong, by an activation mechanism, such as a lifting or other dedicated mechanism.

[0006] Generally, the vibrating element extends in a curvilinear direction in the watch case, for example around a central axis of said case. During the impact of the hammer on the vibrating element, the hammer generates forces on the vibrating element causing its vibration and consequently, the sound of the ringing. These forces include 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.

Summary of the invention

[0008] The invention resolves the aforementioned drawbacks by proposing, for this purpose, a watch movement comprising a striking mechanism for a watch comprising a vibrating element and a device for striking said vibrating element. The striking device comprises a hammer fixed cantilevered to a structure of the watch movement via at least two elastic blades forming a flexible guide. The two blades are each arranged so as to extend in intersecting directions at a point C disposed on an axis T tangent to the vibrating element, in particular tangent to a surface of the vibrating element intended to be hit by the hammer of the striking device.

[0009] In particular embodiments, the invention may also include one or more of the following characteristics, taken in isolation or in all technically possible combinations.

[0010] In particular embodiments, the striking device comprises at least one elastic blade arranged so that the direction in which it extends does not pass through point C.

[0011] 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 intersecting directions at a point of intersection on the axis T, said points of intersection of the directions of the blades of each group being distinct from each other.

[0012] In particular embodiments, the striking device is fixed to the structure of the watch movement only by a mechanical connection of the embedding type.

[0013] In particular embodiments, at least the blades are made of silicon, by deep reactive ion etching.

[0014] In particular embodiments, at least the blades are produced by laser machining, in particular by femtosecond laser, or by electroerosion.

[0015] In particular embodiments, the striking device is in one piece.

[0016] In particular embodiments, the striking device is made of amorphous metal, by molding or by hot forming.

[0017] In particular embodiments, the striking device is made of nickel or nickel phosphorus, by the LIGA process.

[0018] In particular embodiments, the blades have a thickness lower than that of the hammer.

Brief description of the figures

[0019] Other characteristics and advantages of the invention will appear on reading the following detailed description given by way of non-limiting example, with reference to the appended drawings in which: – Figure 1 schematically represents a top view of a striking mechanism comprising a striking device in a rest state, according to a preferred embodiment of the invention; – Figure 2 schematically represents a top view of a striking mechanism comprising a striking device in a rest state, according to another embodiment of the invention; – Figure 3 schematically represents a cross-sectional view of the striking device of the striking mechanism of Figure 1 or 2.

Note that the figures are not necessarily drawn to scale for reasons of clarity.

Detailed description of the invention

Figure 1 shows a striking mechanism 10 of a watch movement of a watch in a preferred embodiment of the invention.

The ringing mechanism 10 comprises a vibrating element 11 and a striking device 120 intended to impact said vibrating element 11 in order to cause the production of a sound. The vibrating element 11 is fixed to a structure of the watch movement, for example to a bridge, to a plate, etc., and is, in the exemplary embodiment shown in Figure 1, formed by a gong.

The striking device 120 comprises a hammer 121 fixed cantilevered to the structure of the watch movement via several blades 122 forming a flexible guide. The blades 122 have an elastic deformation capacity and are used in the present invention for guiding and driving the hammer 121. The blades 122 are preferably two in number. In particular, each blade 122 has a rectilinear shape when the striking device 120 is in a rest state, that is to say in an equilibrium position. The flexible guidance formed by the blades 122 is of the type with a remote center of rotation known as “RCC” meaning “Remote Center Compliance” in English.

[0024] In a manner known per se to those skilled in the art, in summary, the striking device 120 is armed by an activation mechanism (not shown in the figures), such as a lift or any other dedicated mechanism, that is to say that the hammer 121 is driven at a distance from the vibrating element 11, so as to force the blades 122 to gradually deform, until reaching a cocked state. Subsequently, in response to the passage of a predefined temporal value of the current time or on instruction from a user, the activation mechanism releases the hammer 121 which is then, under the effect of the return force elastic of the blades 122, driven in percussion on the vibrating element 11, the striking device 120 then being in a percussion state.

Advantageously, the blades 122 make it possible to position the hammer 121 very precisely relative to the structure of the watch movement, and in particular relative to the vibrating element 11, without mechanical play and without lubrication, unlike a conventional pivot d watchmaking. Furthermore, the blades 122 provide a constant quantity of energy to move the hammer 121, during each percussion of the striking device 120 on the vibrating element 11.

As shown schematically in Figures 1 to 3, the 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 movement watchmaker only by a mechanical connection of the embedding type, that is to say that the blades 122 constitute the only mechanical connection between the hammer 121 and the structure.

[0027] In particular, each blade 122 can be fixed to the structure of the watch movement by welding, screwing, gluing, tight fitting, or by any other means suitable to those skilled in the art.

The blades 122 are each arranged so as to extend in intersecting directions at a point C materializing an instantaneous center of rotation disposed on an axis T tangent to the vibrating element 11, as in shows Figure 1. More 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 movement in a direction D perpendicular to the axis T, or in a direction tangent to a direction D perpendicular to the axis T.

[0029] This characteristic has several advantages.

Indeed, this characteristic makes it possible to maximize the normal component of the forces applied by the hammer 121 on the vibrating element 11 during percussion, or even to eliminate any tangential component. Thus, the percussion is more effective in terms of forces transmitted to the vibrating element 11 for given elastic characteristics of the blades 122, which generates a greater sound volume produced by said percussion.

[0031] Furthermore, this characteristic allows better control of the position of the striking point of the hammer 121 on the surface of the vibrating element 11, and thus allows better control of the vibratory reaction of said vibrating element 11 and therefore of the The sound effect produced during percussion. More precisely, the sound effect produced during percussion is different depending on whether the point of impact is located on a node or on a vibration belly of a vibration mode of the vibrating element 11.

[0032] Finally, the use of a flexible guide and its particular arrangement makes it possible to reduce the bulk of the striking device 120 and to considerably reduce the number of parts constituting said device, to the extent that said flexible guide plays the role of both a pivot role and an elastic recall role.

[0033] It should be noted that the striking device 120 may comprise more than two elastic blades 122 arranged so as to extend in secant directions at the same point C on the axis T. This characteristic makes it possible to increase the impact force of the hammer 121 on the vibrating element, for a given stroke.

[0034] 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 in Figure 2, it is possible that the device striker 120 comprises blades 122 arranged so as to form several groups of blades 122 in each of which the blades 122 extend in intersecting directions at a point of intersection on the axis T, the points of intersection of the directions of the blades 122 of each group being distinct from each other. This characteristic makes it possible to increase the stroke of the hammer 121.

Preferably, the striking device 120 is in one piece. Thus, the striking device 120 is particularly simple to produce, and its manufacturing cost is contained. Furthermore, the mechanism is not likely to suffer from a loss of power during percussion linked to possible mechanical play which could have existed if the striking device 120 was designed by assembling various parts.

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

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 by the skilled in the art under the acronym DRIE meaning Deep Rective Ion Etching in English. The blades 122 can, alternatively, be made of steel, and formed by laser machining, in particular by femtosecond laser, or by electroerosion.

[0038] In particular, the hammer 121 may comprise one or more masses made of a metallic material, for example tungsten or steel, to which the blades 122 are fixed by driving, gluing, by screw or pin.

Advantageously, the blades 122 have a thickness lower than that of the hammer 121, as visible in the schematic sectional view of Figure 3. This characteristic makes it possible to increase the mass of the hammer 121 relative to that of the blades 122 , and therefore to increase the energy provided by the latter during percussion against the vibrating element 11.

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

[0041] More generally, it should be noted that the modes of implementation and embodiment considered above have been described by way of non-limiting examples, and that other variants are therefore possible.

In particular, the hammer has a trapezoidal shape in the exemplary embodiments shown in Figures 1 and 2, but it can alternatively have any shape suitable for producing percussion.

[0043] Furthermore, in the exemplary embodiments shown in Figures 1 and 2, the vibrating element 11 is formed by a stamp comprising a strand extending in a circular direction inside which is arranged the device of strike 120. Alternatively, the strike device 120 could be arranged outside the stamp strand.

[0044] Furthermore, the vibrating element 11 can adopt any suitable shape allowing it to vibrate following the percussion of a hammer and to generate a sound by vibrating, such as a bell or a gong.

Claims (10)

1. Watch 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 cantilevered to a structure of the watch movement via at least two elastic blades (122) forming a flexible guide, said striking mechanism (10) being characterized in that said blades (122) are arranged one and the other of so as to extend in intersecting directions at a point C arranged on an axis T tangent to the vibrating element (11). 2. Watch movement according to claim 1, in which the striking device (120) comprises at least one elastic blade (122) arranged so that the direction in which it extends does not pass through point C. 3. Watch movement according to claim 2, in which the striking device (120) comprises blades (122) arranged so as to form several groups of blades (122) in each of which the blades (122) extend according to intersecting directions at a point of intersection on the axis T, said points of intersection of the directions of the blades (122) of each group being distinct from each other. 4. Watch movement according to one of claims 1 to 3, in which the striking device (120) is fixed to the structure of the watch movement only by a mechanical connection of the embedding type. 5. Watch movement according to one of claims 1 to 4, in which at least the blades (122) are made of silicon, by deep reactive ion etching. 6. Watch movement according to one of claims 1 to 4, in which at least the blades (122) are produced by laser machining, in particular by femtosecond laser, or by electroerosion. 7. Watch movement according to one of claims 1 to 6, wherein the striking device (120) is in one piece. 8. Watch movement according to claim 7, in which the striking device (120) is made of amorphous metal, by molding or by hot forming. 9. Watch movement according to claim 7, in which the striking device (120) is made of nickel or nickel phosphorus, by the LIGA process. 10. Watch movement according to one of claims 1 to 9, in which the blades (122) have a thickness less than that of the hammer (121).