CH718729A2 - Percussion striking mechanism, in particular for watchmaking. - Google Patents

Abstract

The invention relates to a percussion striking mechanism (1), in particular for a clockwork movement, the mechanism (1) comprising at least one resonant element (5) making it possible to emit a sound when it is struck, and a hammer (8) movable between a rest position (9) and a shock position in which it strikes the resonant element (5) to make it vibrate, characterized in that it comprises a system for actuating the hammer (8) comprising a movable striker (16, 17, 18) configured to pass from a trigger position to a percussion position in which it transmits to the hammer (8) at least part of its momentum in order to make it pass from its rest position (9) to its impact position to cause the resonant element (5) to vibrate. The invention also relates to a clock movement comprising such a striking mechanism (1).

Description

Technical field of the invention

The invention relates to a percussion striking mechanism, in particular for watchmaking.

The invention also relates to a clock movement comprising such a striking mechanism.

Technology background

[0003] In the field of watchmaking, a striking mechanism can be combined with a traditional watch movement to serve in particular as minute repeaters or to signal a programmed alarm time. Such a striking mechanism generally comprises at least one gong made of sapphire, quartz or metallic material, such as steel, bronze, precious metal or metallic glass. This gong can describe for example at least a portion of a circle around the watch movement in the watch cage. The stamp is fixed by at least one of its ends to a stamp holder, which is itself secured to a watch plate. A hammer of the mechanism is rotatably mounted on the plate, for example near the gong holder, so as to strike the gong to make it vibrate. The sound produced by the stamp struck by the hammer lies in particular in the audible frequency range of 1 kHz to 20 kHz. This allows the wearer of the watch to be notified of a well-defined time, a programmed alarm or a minute repeater.

[0004] As shown in patent document EP 1 574 917 A1, the striking mechanism of a watch may comprise two or more stamps fixed by one of their ends to the same stamp holder, which is itself integral with a turntable. Each stamp can be struck by a respective hammer. To do this, each hammer is driven by its own drive spring, which had to be wound beforehand, so as to drive the hammer against the gong, in order to signal a minute repeater or an alarm hour. Two damping counter-springs are each provided to push back and maintain the two hammers at a distance from the gongs in a rest mode. In a striking mode, the damping counter-springs act with great force and slow the fall of each hammer before striking against the respective gong. These counter-springs make it possible, following the strike, to push back each hammer towards their rest position. Eccentrics are also provided for adjusting the operation of the counter-springs to essentially prevent any bouncing of each hammer against the respective gong.

[0005] A disadvantage of such a structure of the striking mechanism with these counter-springs is that there is a significant loss of kinetic energy of the hammer when striking the respective gong, which reduces the acoustic level of the alarm. This loss of energy is largely due to the slowdown imposed by each counter-spring on the path of the hammer when it strikes against the gong. Moreover, even if the pre-winding of the drive springs is increased, this implies an adaptation of the counter-springs via their eccentric to also avoid any rebound, which is another drawback of such a striking mechanism.

Summary of the invention

[0006] The object of the invention is therefore to overcome the drawbacks of the aforementioned state of the art by providing a striking mechanism for a timepiece, with the aim of avoiding a significant loss of energy during the fall of the hammer against the gong.

[0007] To this end, the invention relates to a striking mechanism, in particular for watchmaking, the mechanism comprising at least one resonant element making it possible to emit a sound when it is struck, and a movable hammer between a rest position and a shock position in which it hits the resonant element to make it vibrate.

[0008] The mechanism is remarkable in that it comprises a system for actuating the hammer comprising a movable striker configured to pass from a trigger position to a percussion position, in which it transmits to the hammer a quantity of movement in order to to move it from its rest position to its impact position to cause the resonant element to vibrate.

[0009] Thus, the quantity of movement provided by a striker is used to operate the hammer. Thanks to the momentum of the striker, the hammer receives enough energy to strike the gong and cause it to vibrate. Furthermore, by selecting a particular mass difference between the hammer and the striker, one can adapt the speed of the hammer. For example, one can choose a hammer of reduced mass, which moves to strike the gong with a greater speed than that of the striker having a greater mass.

[0010] Thanks to this ringing mechanism, the energy necessary for actuating the hammer is saved. In addition, a lighter, faster-moving hammer decreases the risk of kickback after striking the gong.

According to a particular embodiment of the invention, the mechanism comprises a magnet fixed relative to the clockwork, the magnet being configured to attract the movable striker into the percussion position.

According to a particular embodiment of the invention, the hammer comprises a magnetic conductive material.

According to a particular embodiment of the invention, the striker comprises a magnetic conductive material, so as to be attracted by the magnet.

According to a particular embodiment of the invention, the hammer is in contact with the magnet in its rest position.

According to a particular embodiment of the invention, the striker is configured to strike the magnet so as to give an impulse to the hammer.

According to a particular embodiment of the invention, the distance between the firing position of the striker and the magnet is chosen so that the magnet attracts the striker against it in its percussion position.

According to a particular embodiment of the invention, the amount of movement transmitted by the striker is large enough to overcome the retaining force of the magnet acting on the hammer, so that the hammer is detached from the magnet and strikes the resonant element.

According to a particular embodiment of the invention, the mechanism comprises a flexible guide on which the hammer is mounted to allow it to move between its rest position and its impact position.

According to a particular embodiment of the invention, the flexible guide is configured to press the hammer against the magnet.

According to a particular embodiment of the invention, the actuation system comprises a flexible guide on which the striker is mounted to allow it to move between the trigger position and the percussion position.

According to a particular embodiment of the invention, the flexible guide comprises a flexible blade or a flexible neck.

According to a particular embodiment of the invention, the actuation system comprises a rotary device fitted with the striker, the rotary device being configured to bring the striker into the trigger position.

According to a particular embodiment of the invention, the actuation system comprises at least one additional striker, preferably two additional strikers, arranged on the rotary device, so as to alternately bring each striker into the trigger position .

According to a particular embodiment of the invention, the rotary device comprises a rotary hub.

According to a particular embodiment of the invention, the rotary device comprises at least one arm, each arm carrying a striker.

According to a particular embodiment of the invention, the rotary device comprises several arms distributed angularly around the hub.

According to a particular embodiment of the invention, the mass of the striker is greater than that of the hammer, for example, the mass of the striker is at least twice as great as that of the hammer.

The invention also relates to a clock movement comprising such a striking mechanism.

Brief description of figures

Other features and advantages will emerge clearly from the description given below, by way of indication and in no way limiting, with reference to the appended drawings, in which: FIG. 1 is a schematic representation of a timepiece comprising a percussion striking mechanism according to one embodiment of the invention; Figure 2 is an enlarged schematic representation of the striking mechanism of Figure 1; Figure 3 is a schematic representation of the striking mechanism of Figure 1, in which the striker is in the trigger position; Figure 4 is a schematic representation of the striking mechanism of Figure 1, in which the striker is in the percussion position with the magnet and the hammer is in the shock position with the gong; and FIG. 5 is a schematic representation of the striking mechanism of FIG. 1, in which the striker is no longer in the percussion position or in the release position and the hammer has returned to the rest position.

Detailed description of the invention

As explained above, the invention relates to a percussion striking mechanism 1. The striking mechanism 1 is intended for a timepiece 10, such as a watch shown in FIG. The clockwork 10 comprises a middle part 2 and a clockwork movement 3, preferably mechanical, which is for example provided with a plate 4 and a mainspring to supply the operating energy. The embodiment described below is based on the combination of the principle of "Gauss's magnetic cannon", and the principle of the conservation of momentum during a shock.

In Figures 1 to 5, the striking mechanism 1 comprises a resonant element 5, for example a stamp conventionally used in clockwork ringtones. The resonant element 5 makes it possible to emit a sound when struck. In the figures, the resonant element 5 is a rod comprising a rectilinear portion 6. The resonant element 5 is preferably fixed to the plate 4, so as to extend above beside the plate 4, for example in a plane parallel to that of the plate.

Other resonant element 5 configurations are possible. The resonant element 5 may further comprise a circular portion 7, shown in Figure 1, in particular to run along the inner face of the middle part 2.

To emit a sound, the mechanism 1 comprises a movable hammer 8 relative to the plate 4. The hammer 8 is movable between two positions, a rest position 9 away from the resonant element 5, and a shock position 11 in which it strikes the resonant element to make it vibrate. Thus, the resonant element 5 produces a vibration which propagates in the watch. The outer part of the watch radiates these vibrations so as to emit sound. Other embodiments are possible with various shapes of hammer 8 and resonant element 5.

The mechanism 1 here comprises a flexible guide 12 on which the hammer 8 is mounted to allow it to move between its rest position 9 and its impact position 11. The flexible guide 12 preferably comprises a first flexible blade 13 assembled to the plate 4 on the one hand, and to the hammer 8 on the other hand. The first flexible blade 13 is preferably arranged substantially parallel to the resonant element 5 when the hammer 8 is in the rest position 9. By the elastic deformation of the first flexible blade 13, the hammer 8 passes from the position of rest 9 to shock position 11 and vice versa.

The mechanism 1 further comprises a magnet 15 fixed relative to the plate 4. The magnet 15 is preferably assembled on the plate 4. The magnet 15 is for example arranged on a promontory 14 vis-à-vis resonant element screw 5.

[0036] Preferably, the magnet 15 is configured to retain the hammer 8 in its rest position 9. For this purpose the hammer 8 comprises a magnetic conductive material, which induces a force of attraction of the hammer 8 against the magnet 15.

Alternatively, one can choose a hammer 8 not comprising any magnetic conductive material. In this case, the flexible guide 12 is configured to apply a prestress on the hammer 8, so as to press it against the magnet 8.

Thus, in the rest position 9, the hammer 8 is in contact with a front face 29 of the magnet 15. The hammer 8 keeps this position permanently, except when it strikes the resonant element 5. The flexible guide 12 is assembled to the plate 4 between the promontory 14 and the resonant element 5. Thus, the hammer 8 can move between the magnet 15 and the resonant element 5 thanks to the flexible guide 12.

The front face 29 preferably has a substantially planar surface. The hammer 8 has for example a cylindrical or spherical shape. These rounded shapes make it easier to separate the hammer 8 from the front face 29 of the magnet 15.

According to the invention, the mechanism 1 comprises a system for actuating the hammer 8. This mechanism is configured to cause the displacement of the hammer 8 from its rest position 9 to its impact position 11. In particular, it serves to separate the hammer 8 from the magnet 15 and allow it to reach the resonant element 5.

[0041] To this end, the actuation system 20 comprises at least one movable striker 16, 17, 18 configured to transmit to the hammer 8 a quantity of movement sufficient for it to pass from its rest position 9 to its position of shock 11 and to vibrate the resonant element 5.

The striker 16, 17, 18 is configured to pass from a trigger position 19 to a percussion position 21 in which it transmits a quantity of movement to the hammer 8.

In the embodiment of Figures 1 to 5, the actuation system comprises a rotary device 20 provided with three movable strikers 16, 17, 18.

The rotary device 20 comprises a hub 22 and three arms 23, 24, 25, distributed angularly around the hub 22, and are connected to the hub 22 by one end. Each arm 23, 24, 25 carries a movable striker 16, 17, 18 disposed at the opposite end of the arm 23, 24, 25 relative to the hub 22. The arms 23, 24, 25 are preferably arranged in the same plane substantially perpendicular to the axis of the hub 22. This plane also preferably passes through the magnet 15, the hammer 8 and the resonant element 5.

[0045] Each movable striker 16, 17, 18 is mounted on an arm 23, 24, 25 so as to form an angle with the arm 23, 24, 25. The angle is between 30 and 60°, when the striker mobile 16, 17, 18 is in trigger position 19, and the angle is between 60 and 90°, when the mobile striker 16, 17, 18 is in percussion position 21. An arm can, for example, be an oblong body , a cog or a plate.

Preferably, each movable striker 16, 17, 18 is mounted on the arm 23, 24, 25 by a flexible guide to allow it to move relative to the arm 23, 24, 25, and to pass from the position trigger 19 to the percussion position 21. The flexible guide here comprises a second flexible blade 26 assembled with the movable striker 16, 17, 18 on the one hand, and on the other hand at the end of the arm 23, 24, 25 .

[0047] Each movable striker 16, 17, 18 comprises a contact face 31, 32, 33, which is intended to come into contact with the magnet 15, when it passes from the trigger position 19 to the percussion position 21. The contact faces 31, 32, 33 of the movable striker 16, 17, 18 are preferably rounded, to allow easier unhooking when the movable striker 16, 17, 18 returns to its trigger position.

When the rotary device 20 rotates, it positions one of the movable strikers 16, 17, 18 opposite the magnet 15. The movable striker 16, 17, 18 then moves from the trigger position 19 to the percussion position 21 according to a radial displacement. Once the percussion has been performed, the rotary device 20 continues to rotate in order to prevent the movable striker 16, 17, 18 from remaining against the magnet 15. The geometry of the movable strikers 16, 17, 18 is made in such a way as to require the least possible torque on the rotary device 20. For example, a contact face 32 is chosen having the shape of a ramp tangential to the rotary movement.

The rotary device 20 is actuated by rotating the hub 22 around its axis, so that the arms 23, 24, 25 rotate around the axis of the hub 22. Thus, the movable strikers 16, 17, 18 also rotate around the axis of the hub 22 while remaining in the trigger position 19. In other words, the movable strikers 16, 17, 18 remain in the same position relative to the arms 23, 24, 25, which carry them.

To rotate, the means 22 is mechanically connected to the barrel of the movement via gear means, not shown in the figures. These gear means comprise for example an actuation system configured to determine the chimes to be executed according to the time displayed by the movement 3, in particular to serve as minute repeaters or to signal a programmed alarm time. Thus, when one or more bells should sound, the actuation system triggers the rotation of the hub 22.

The rotary device 20 is configured to bring the striker into the trigger position 21 in front of the magnet 15. Figure 3 shows an example in which the striker 21 is in the trigger position closest to the magnet 15. The magnet 15 has an opposite face 30 oriented towards the rotary device 20, so that the opposite face 30 of the magnet 15 and a contact face 31, 32, 33 of a movable striker 16, 17, 18 are opposite -to-vis when the rotating device 20 rotates. The opposite face 30 preferably has a substantially planar surface.

The force of attraction of the magnet 15 and the distance between the contact face 31, 32, 33 of the movable striker 16, 17, 18 in the release position and the opposite face 30 of the magnet 15 are chosen , so that the magnet 15 attracts the striker 16 against its opposite face 30, when it passes in front of its opposite face 30. Thus, the magnetic potential energy produced by the magnet 15 acting on the movable striker 16, 17, 18 is transformed into kinetic energy by the movable striker 16, 17, 18. This kinetic energy is transmitted to the hammer 8 by the impact of the movable striker 16, 17, 18.

Indeed, when the movable striker 16, 17, 18 is attracted by the magnet 15, it is accelerated and strikes the magnet 15. When the movable striker 16, 17, 18 collides with the opposite face 30 of the magnet 15, at least part of its momentum is transmitted to the hammer 8 through the magnet 15, the hammer 8 being placed against the front face 29 of the magnet in the rest position.

[0054] This principle of motion transmission combined with magnetic attraction is known as the “Gauss cannon”. The attraction of the magnet 15 guarantees a minimum intensity with each strike of the hammer 8. The ringing which results therefrom is more constant over the entire duration of the ringing, independently of the barrel torque.

As shown in Figure 4, each movable striker 16, 17, 18 is configured to strike the magnet 15 so as to give an impulse to the hammer.

Furthermore, the movable strikers 16, 17, 18 and the rotary device 20 are configured so that the quantity of movement transmitted to the hammer 8 by the striker 16, 17, 18 is greater than the retaining force of the magnet. acting on the hammer 8, so that the hammer detaches from the magnet 15 and strikes the resonant element 5 with sufficient force, as shown in Figure 4.

As shown in Figure 5, the magnet 15 and the hammer 8 are further configured so that the front face 29 attracts the hammer 8 against it, after the latter has struck the resonant element 5. Thus , the hammer 8 returns to its rest position 9, and can again be actuated by the movable striker 16, 17, 18 next. It is also avoided that the hammer 8 rebounds and hits the resonant element 5 again inappropriately.

In the case of a hammer 8 not comprising any magnetic conductive material, the flexible guide 12 brings the hammer back against the magnet 15.

Continuing to rotate, the rotation device 20 pulls on the movable striker 16, 17, 18 so that the latter detaches from the opposite face 30 of the magnet 15. At the same time, when the hub 22 rotates, the next movable striker 16, 17, 18 approaches the magnet 15.

[0060] The rotation device 20 is actuated by the movement, when a bell is required. Thus, the ringing sounds automatically thanks to the movable strikers 16, 17, 18, the magnet 15, the hammer 8 and the resonant element 5.

In operation, each movable striker 16, 17, 18 strikes the magnet 15 one after the other, to produce a sound each time. With each percussion of a movable striker 16, 17, 18, the hammer 8 strikes the resonant element 5, and returns to the rest position 9 against the magnet 15 between two successive percussions.

[0062] Depending on the number of ringtones to be emitted, the rotation device is actuated for a predefined time.

[0063] Preferably, the rotation takes place at constant speed so that the ringtones are emitted periodically at the same frequency.

[0064] The speed of rotation can also be variable to emit a particular ringtone.

Of course, the present invention is not limited to the example illustrated but is susceptible to various variants and modifications which will become apparent to those skilled in the art. In particular, the device may comprise a greater or lesser number of arms and strikers than those illustrated in the embodiment described.

Claims (15)

1. Percussion striking mechanism (1), in particular for a clock movement (3), the mechanism (1) comprising at least one resonant element (5) making it possible to emit a sound when it is struck, and a hammer (8) movable between a rest position (9) and a shock position (11) in which it strikes the resonant element (5) to make it vibrate, characterized in that it comprises a system for actuating the hammer (8) comprising a movable striker (16, 17, 18) configured to pass from a trigger position (19) to a percussion position (21) in which it transmits to the hammer (8) at least part of its quantity of movement in order to move it from its rest position (9) to its impact position (11) to cause the resonant element (5) to vibrate. 2. Striking mechanism according to claim 1, characterized in that it comprises a fixed magnet (15) relative to the clock movement (3), the magnet (15) being configured to attract the movable striker (16, 17, 18) in the percussion position (21). 3. Striking mechanism according to claim 2, characterized in that the hammer (8) is in contact with the magnet (15) in its rest position (9). 4. Striking mechanism according to claim 3, characterized in that the striker (16, 17, 18) is configured to strike the magnet (15) so as to give an impulse to the hammer (8) via the magnet (15) . 5. Striking mechanism according to claim 4, characterized in that the distance between the trigger position (19) of the movable striker (16, 17, 18) and the magnet (15) is chosen, so that the magnet (15) attracts the movable striker (16, 17, 18) against it in its percussion position (21). 6. Striking mechanism according to Claim 4 or 5, characterized in that the quantity of movement transmitted by the movable striker (16, 17, 18) overcomes the magnetic retaining force of the magnet (15) acting on the hammer ( 8), so that the hammer (8) detaches from the magnet (15) and strikes the resonant element (5). 7. Striking mechanism according to any one of the preceding claims, characterized in that it comprises a flexible guide (12) on which the hammer (8) is mounted to allow it to move between its rest position ( 9) and its impact position (11). 8. Striking mechanism according to any one of the preceding claims, characterized in that the actuation system comprises a flexible guide on which the movable striker (16, 17, 18) is mounted to allow it to move between the trigger position (19) and the percussion position (21). 9. Striking mechanism according to claim 7 or 8, characterized in that the flexible guide (12) comprises a flexible blade (13, 26, 27, 28), or a flexible neck. 10. Striking mechanism according to any one of the preceding claims, characterized in that the actuation system comprises a rotary device (20) provided with the movable striker (16, 17, 18), the rotary device being configured to bring the movable striker (16, 17, 18) into the trigger position (19). 11. Striking mechanism according to claim 7, characterized in that the actuation system comprises at least one additional striker (16, 17, 18), preferably two additional strikers, arranged on the rotary device (20), so alternately bringing each movable striker (16, 17, 18) into the trigger position (19). 12. Striking mechanism according to any one of the preceding claims, characterized in that the rotary device (20) comprises a hub (22). 13. Striking mechanism according to claim 7, characterized in that the rotary device (20) comprises at least one arm (22, 23, 24), each arm (22, 23, 24) carrying a movable striker (16, 17 , 18). 14. Striking mechanism according to claim 7, characterized in that the rotary device (20) comprises several arms (22, 23, 24) distributed angularly around the hub (22). 15. Clock movement (3), characterized in that it comprises a striking mechanism (1) according to any one of the preceding claims.