Especially for watches, thermally operated micromechanical devices

Abstract

We provide a thermally operated micromechanical device. [Solution] The present invention relates to a thermally operated micromechanical device 1, particularly a thermally operated micromechanical device for a watch movement, wherein the micromechanical device comprises a mechanically operable first movable body 3 and a mechanically operable second movable body 4, the second movable body being translationally movable relative to the first movable body between a coupled position in which the first movable body mechanically engages with the second movable body and acts it, and a stationary position in which the second movable body cannot mechanically engage with the first movable body, and the micromechanical device comprises a support 5 to which the second movable body is attached, the support being thermally deformable to move the second movable body from the stationary position to the coupled position and / or vice versa.

Description

Technical Field

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[0001] The present invention relates to the field of point-actuable micromechanical devices, and more specifically to the field of thermally actuated micromechanical devices, particularly for use in timepieces.

Background Art

[0002] In a gear mechanism, it may be necessary to use a point-actuable micromechanical device. More specifically, in the field of timepieces, there are mechanisms for adjusting a specific timepiece module such as time or date, or for setting the pace of a movement.

[0003] These mechanisms are point-actuated to mechanically engage gears.

[0004] To operate these, these mechanisms require devices accessible from outside the timepiece, such as a winding crown and winding arbor for setting time, or require opening the timepiece case to access the timepiece module, for example when setting the pace.

[0005] Actuation from outside the case requires adding components to the movement to enable access to the timepiece module to be actuated, making the movement more complex. The case must also be waterproof.​​​​​​​​​​​However, these micromechanical devices do not allow for sufficient setting accuracy. [Overview of the Initiative]

[0009] The object of the present invention is to eliminate all or part of the above-mentioned drawbacks by proposing a micromechanical device for precise settings that can be operated from outside the case.

[0010] Therefore, the present invention relates to a thermally operated micromechanical device, more particularly a thermally operated micromechanical device for a watch movement, the micromechanical device comprising a first mechanically actuated movable body and a second mechanically actuated movable body, the second movable body being translationally movable relative to the first movable body between a coupled position in which the first movable body mechanically engages with the second movable body and acts it, and a disengaged stationary position in which the second movable body cannot mechanically engage with the first movable body, the micromechanical device comprising a support to which the second movable body is attached.

[0011] The present invention is distinguished in that the support is thermally deformable, thereby moving the second movable body from the stationary position to the coupled position and / or vice versa.

[0012] This invention provides a micromechanical device for mechanically connecting two moving bodies by thermal action. As a result, no additional mechanical mechanism is required to connect the two moving bodies.

[0013] This device is easy to manufacture and can be remotely operated by heating the support.

[0014] Furthermore, such devices can be operated from outside the case and can be used, for example, in watches where it is desirable to perform settings without opening the case. In fact, the micromechanical device can be operated by heating while the case is closed.

[0015] According to a particular embodiment of the present invention, the support comprises a shape memory material that is at least partially, preferably completely, thermally deformable when a threshold temperature is exceeded.

[0016] According to a particular embodiment of the present invention, the threshold temperature is between 60°C and 80°C, preferably between 65°C and 75°C, or even more substantially equal to 70°C.

[0017] According to a particular embodiment of the present invention, the support is a lever.

[0018] According to a particular embodiment of the present invention, the lever includes a curved portion, and the lever is straightened to move the second movable body from the stationary position to the coupled position.

[0019] According to a particular embodiment of the present invention, the second movable body is positioned within or immediately adjacent to the curved portion of the lever.

[0020] According to a particular embodiment of the present invention, the micromechanical device includes an axis positioned perpendicular to the first end of the lever such that the lever forms a rotatable pivot.

[0021] According to a particular embodiment of the present invention, the support comprises a small gear that meshes with the second movable body.

[0022] According to a particular embodiment of the present invention, the first movable body is a gear.

[0023] According to a particular embodiment of the present invention, the second movable body is a gear.

[0024] According to a particular embodiment of the present invention, the micromechanical device includes a return spring for pushing the second movable body back to the stationary position.

[0025] The present invention also relates to a watch movement equipped with such micromechanical devices.

[0026] According to a particular embodiment of the present invention, the timepiece movement includes a floor or a receptacle with a seat for the support.

[0027] According to a particular embodiment of the present invention, the seat includes an edge forming a support for the second end of the lever.

[0028] The present invention also relates to a timepiece including such a timepiece movement.

Brief Description of the Drawings

[0029] The objectives, advantages and features of the present invention will become apparent by reading the following attached drawings, referring to multiple embodiments given only as non-limiting examples. [Figure 1] FIG. 1 is a schematic perspective view of a part of a timepiece movement provided with a thermally actuated micro-mechanical device in a first configuration. [Figure 2] FIG. 2 is a schematic perspective view of a part of the timepiece movement of FIG. 1, where the thermally actuated micro-mechanical device is in a second configuration. [Figure 3] FIG. 3 is a schematic perspective view of a part of the thermally actuated micro-mechanical device. [Figure 4] FIG. 4 is a schematic plan view of a part of the thermally actuated micro-mechanical device. [Figure 5] FIG. 5 is a schematic perspective view of a part of a setting mechanism driven by a micro-mechanical device according to the present invention.

Embodiments for Carrying Out the Invention

[0030] FIGS. 1 and 2 show schematic views of one embodiment of a thermally actuated device 1 designed to be mounted within a timepiece movement 10. The timepiece movement 10 includes a floor 11 and a seat 12 provided on the floor 11 for accommodating the thermally actuated device 1.

[0031] The watch movement 10 further includes a main setting movable body 2, which drives the watch module mechanism.

[0032] The main movable part 2 is, for example, a date drive wheel. Such a wheel has a high gear ratio with respect to the winding stem shaft and enables the achievement of precise setting resolution.

[0033] The clock module includes a mechanism for setting the rate of the clock movement, which is actuated, for example, by a cam 14 shown in Figure 5. This means that the setting mechanism functions when the main movable body 2 is actuated.

[0034] The thermally operated device 1 further comprises a first mechanically movable body 3, in this case a first gear, and a second mechanically movable body 4, in this case a second mechanically movable body.

[0035] The first mechanical movable body 3 engages with the main movable body 2 so that it can be operated. Therefore, by rotating the main movable body 2, the first mechanical movable body 3 is rotated, thereby activating the setting mechanism on the clock module associated with the first mechanical movable body 3.

[0036] The second mechanically movable body 4 is movable relative to the first mechanically movable body 3, and is movable between a coupling position in which the first mechanically movable body 3 engages with the second mechanically movable body 4 and a stationary position in which the first mechanically movable body 3 does not engage with the second mechanically movable body 4.

[0037] For this purpose, the second mechanically movable body 4 is mounted on the support 5, and the support 5 is configured to allow the second mechanically movable body 4 to move from a stationary position to a coupled position, and vice versa.

[0038] In this embodiment, the support 5 is substantially a longitudinal lever. The lever includes a curved portion 7 that joins two substantially straight portions. The lever includes two ends 9, 15.

[0039] Preferably, the second mechanically movable body 4 is positioned within the curved portion 7 of the lever, which moves over a longer distance than the straight portion.

[0040] In Figure 3, the support 5 also includes a small gear 6 and a shaft 8 positioned at the first end 9 of the lever, with the small gear 6 mounted on the shaft 8. The shaft 8 is mounted through the base plate 11 and the support 5. Thus, the first end 9 of the lever is held within the seat 12. However, the shaft 8 forms a pivot from which the lever can rotate.

[0041] The small gear 6 meshes with the second mechanically movable body 4 regardless of its position. When the second mechanically movable body 4 is driven, the small gear 6 actsuates the shaft. The shaft 8 is connected to a gear mechanism (not shown), which is actuated, preferably point-actuated, and actuated, for example, by the wearer of a watch equipped with this movement.

[0042] According to the present invention, the support 5 is thermally deformable between two configurations: a first configuration in which the second mechanically movable body 4 is in a coupled position, and a second configuration in which the second mechanically movable body 4 is in a stationary position, as shown in Figure 2.

[0043] More specifically, the support 5 deforms thermally when the threshold temperature is exceeded. Preferably, the support 5 deforms to become a bonding position when the threshold temperature is exceeded.

[0044] Therefore, the support 5 includes a shape memory material. Such a material deforms when the temperature exceeds a threshold temperature and returns to its initial shape below this threshold temperature.

[0045] Various types of shape memory materials are possible.

[0046] For example, a copper-based alloy having the following composition by weight may be used. Cu is 64.5-85%, Zn is 9.5-25%, and Al is 4.5-10%. Cu is 79.5-84%, Al is 12.5-14%, and Ni is 2.5-6%. • Cu is 87-88%, Al is 11-12%, and Be is 0.3-0.7%.

[0047] Gold-based alloys such as 50Au40Ti10Zr, 52Au47Ti1Zr, and 50Au45Ti3Zr2Nb also exist, and for example, they have the following compositions in atomic percentages. Gold at 46-55% Titanium is 38-47 at%, • Zirconium content: 0.1-15 at%, Niobium is present at 0-5% at.

[0048] Nickel-titanium alloys, such as nitinol, or even plastics may be used as shape memory materials for the support.

[0049] Therefore, when the temperature rises above the threshold temperature, the lever straightens, moving the second mechanically movable body 4 from its stationary position to its coupled position, thereby allowing the second mechanically movable body 4 to be driven by the first mechanically movable body 3 and thus by the main movable body 2. When the lever deforms, the ends 9 and 15 of the lever remain substantially in the same position. However, the curvature of the curved portion 7 of the lever decreases.

[0050] The curved portion 7 moves inward toward the first mechanically movable body 4.

[0051] The seat 12 on the base plate 11 has an edge 13 that forms a support for the second end 15 of the lever. The seat 12 is designed to allow deformation of the lever. In this case, the shape of the seat widens from the edge 13 for the second end 15. The curved portion 7, and therefore the second mechanically movable body 4, moves within the seat 12 under the influence of deformation.

[0052] When the temperature returns to below the threshold temperature, the lever returns to its original shape with a more pronounced curve. The second mechanically movable body 4 is then detached again from the first mechanically movable body 3 and can no longer be driven by the latter.

[0053] The threshold temperature is, for example, between 60°C and 80°C, preferably between 65°C and 75°C, or even substantially equal to 70°C. This temperature range is high enough to avoid undesirable induction of material deformation due to, for example, high external temperatures, but not excessively high to avoid the risk of deterioration of elements within the movement, such as oil.

[0054] Alternatively, the threshold temperature can be selected within a negative temperature range, for example, below -20°C.

[0055] As a variation, the selected material has two different threshold temperatures: a first threshold temperature for moving from a stationary position to a bonded position, and a second threshold temperature for moving from a bonded position to a stationary position.

[0056] To improve transitions between positions, particularly to return to a stationary position, the micromechanical device may be equipped with a return spring (not shown) which pushes the lever, and therefore the second mechanically movable body, back to the stationary position.

[0057] Figure 5 shows part of a setting mechanism driven by a thermally operated micromechanical device. A third geared movable body 16 is attached to the other end of the shaft 8 and meshes with a cam movable body 17, which includes a cam 14. The cam 14 interacts with another part of the setting mechanism (not shown), which includes a stylus spindle or a movable ratchet and allows for setting, for example, the rate. Thus, when the first movable body 3 is in the coupled position, the cam 4 is driven.

[0058] In a modified embodiment, although not shown, the cam-movable body is replaced by a movable body with an eccentric body. Such an eccentric body can engage with a setting mechanism that cooperates with the eccentric body.

[0059] A watch movement equipped with such a micromechanical device 1 can be mounted on a watch. For this purpose, the watch has a case closed by a back cover.

[0060] The case back is transparent, for example, to allow laser radiation to pass through to the watch movement, particularly to the support for the micromechanical device. The laser radiation is configured to heat and deform the support for the micromechanical device.

[0061] Naturally, the present invention is not limited to the embodiments of the speed regulator described with reference to the drawings, and modifications may be envisioned without departing from the scope of the present invention.

Claims

1. A thermally operated micromechanical device (1) particularly for watch movements, The micromechanical device (1) comprises a mechanically operable first movable body (3) and a mechanically operable second movable body (4), The second movable body (4) is capable of translational movement relative to the first movable body (3) between a coupling position in which the first movable body (3) mechanically engages with the second movable body (4) and operates it, and a stationary position in which the second movable body (4) cannot mechanically engage with the first movable body (3). The micromechanical device (1) comprises a support (5) to which the second movable body (4) is attached. The support (5) is a thermally deformable thermally operated micromechanical device (1) that moves the second movable body (4) from the stationary position to the coupled position and / or vice versa.

2. The thermally operated micromechanical device (1) according to claim 1, wherein the support (5) comprises at least partially, preferably completely, a shape memory material that is thermally deformable when a threshold temperature is exceeded.

3. The thermally operated micromechanical device (1) according to claim 2, wherein the threshold temperature is between 60°C and 80°C, preferably between 65°C and 75°C, or even more substantially equal to 70°C.

4. The thermally operated micromechanical device (1) according to claim 1, wherein the support (5) is a lever.

5. The thermally operated micromechanical device (1) according to claim 4, wherein the lever includes a curved portion (7), and the lever is straightened to move the second movable body (4) from the stationary position to the coupled position.

6. The thermally operated micromechanical device (1) according to claim 5, wherein the second movable body (4) is positioned within or immediately adjacent to the curved portion (7) of the lever.

7. The thermally operated micromechanical device (1) according to claim 4, further comprising an axis (8) positioned perpendicular to the first end (9) of the lever so as to form a pivot from which the lever can rotate.

8. The thermally operated micromechanical device (1) according to claim 1, wherein the support (5) comprises a small gear (6) that meshes with the second movable body (4).

9. The thermally operated micromechanical device (1) according to claim 1, wherein the first movable body (3) and the second movable body (4) are gears.

10. The thermally operated micromechanical device (1) according to claim 1, further comprising a return spring for pushing the second movable body (4) back to the stationary position.

11. A watch movement comprising the micromechanical device (1) described in claim 1.

12. The clock movement according to claim 11, comprising a base plate (11) or receiver having a seat (12) for the support (5).

13. The watch movement according to claims 12 and 4, wherein the seat (12) comprises an edge (13) that forms a support for the second end (15) of the lever.

14. A watch comprising the watch movement described in claim 11.

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