Tourbillon mechanisms for watch movements

Abstract

The present invention relates to a tourbillon mechanism (1) for a timepiece movement, comprising: a rotary support (3) pivotally mounted to a base (5) so as to be rotatable about a first axis of rotation (A1) and configured to be rotated by a drive source (S); an oscillator (7) pivotally mounted to the rotary support (3) so as to be rotatable about a second axis of rotation (A2); a blocking member (11) attached to the rotary support (3) and configured to be controlled by the rotation of the oscillator (7) to block and release the rotation of the rotary support (3); an escape wheel (9) attached to the base (5) so as to rotate integrally with the base (5) and configured to cooperate with the blocking member (11); and a direct impulse member (15) attached to the second axis of rotation (A2) and configured to cooperate with the escape wheel (9) to give an impulse to the oscillator (7) during rotation of the rotary support (3).

Description

[Technical Field]

[0001] The present invention relates to the field of watchmaking, more particularly to tourbillon mechanisms for watch movements. [Background technology]

[0002] Patent document 1 (CH701490) describes a tourbillon with a "Potter" type escapement having a fixed escape wheel.

[0003] In this mechanism, a balance-hairspring oscillator is mounted on a rotating cage that is adapted to be rotated by a drive source, the axis of rotation of the balance being coaxial with that of the cage, and the cage also carries a pallet that cooperates on the one hand with the oscillator in a known manner and on the other hand with a fixed escape wheel that is fixed in integral rotation to a frame element.

[0004] This configuration minimizes the number of elements carried by the cage and the angular inertia of the tourbillon, allowing for significantly faster cage rotation, on the order of a few seconds compared to the 30 seconds to several minutes required for a conventional tourbillon.

[0005] This type of escapement is also used in multi-axis tourbillons, particularly the triple-axis tourbillon used in the MB&F® Legacy Machine Thunderdome, which has three cages with rotation speeds of 8, 12, and 20 seconds, respectively, with the escape wheel attached to the middle cage.

[0006] However, Potter escapements produce relatively high friction, making them quite inefficient and negatively affecting the power reserve.

[0007] In one embodiment, Patent Document 2 (CH718204) discloses an escapement in which a fixed escapement crown with internal teeth cooperates with a linearly moving escapement element that provides an indirect impulse to a balance-hairspring oscillator in a manner similar to a traditional Swiss lever escapement. This system is very delicate and fragile, and difficult to complete. Furthermore, due to the relatively high inertia of the chassis and the parts it supports, as well as the friction generated by the movement of the escapement element, the indirect impulse (transmitted to the oscillator at the start of palette release) is relatively small and also quite inefficient, again negatively impacting the power reserve. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Swiss Patent Application Publication No. 701490 [Patent Document 2] Swiss Patent Application Publication No. 718204 Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is therefore to propose a tourbillon mechanism in which the above-mentioned drawbacks are at least partially overcome. [Means for solving the problem]

[0010] More specifically, the present invention relates to a tourbillon mechanism for a timepiece movement as defined in claim 1. This mechanism comprises: a rotary support, such as a plate, a cage, or the like, pivotally mounted on the base so as to be rotatable about a first rotation axis and configured to be rotated by a driving source, such as a mainspring housed in a barrel; an oscillator, usually a balance-hairspring of any known type, pivotally mounted on the rotary support for rotation about a second axis of rotation; a blocking member attached to the rotary support and configured to be controlled directly or indirectly by the rotation of the vibrator to block and release the rotation of the rotary support; an escape wheel attached to the base so as to rotate integrally with the base and configured to cooperate with the blocking member; a direct impulse member (such as an impulse pallet) attached to the second rotary shaft and configured to cooperate with the escape wheel (in particular to cooperate directly with the escape wheel teeth) to impart an impulse to the oscillator during rotation of the rotary support; Equipped with.

[0011] The escapement described above is of the "direct impulse" type, which offers greater efficiency than conventional lever escapements, making it possible to increase the power reserve of movements incorporating a tourbillon mechanism and to maintain the relatively high rotational speed of the rotating support of a "Potter" escapement. It should be noted that the term "tourbillon" should be interpreted broadly.

[0012] Advantageously, the blocking member is a detent lever pivotally mounted on the rotary support so as to be rotatable about a third axis of rotation, the detent lever being adapted to cooperate with a release pallet mounted on a second axis of rotation in order to rotate the detent lever and thereby initiate rotation of the rotary support, the detent lever being subjected to a restoring force tending to maintain it in engagement with the escape wheel and pinion.

[0013] Advantageously, the detent lever is provided with a retractable finger mounted to rotate about a fourth axis of rotation and which cooperates with the release pallet to rotate the detent lever to initiate rotation of the rotary support during a first oscillation of the oscillator and which retracts to allow passage of the release pallet during a second oscillation of the oscillator.

[0014] Advantageously, the retractable finger is subjected to a restoring force exerted by a resilient member which tends to maintain the retractable finger in abutment against a stop carried by the detent lever.

[0015] Alternatively, the blocking member is an anchor.

[0016] Advantageously, the second axis of rotation is different from the first axis of rotation, although these two axes may coincide.

[0017] Advantageously, the second axis of rotation forms an angle of between 1° and 90° with respect to the first axis of rotation, preferably between 10° and 80°, and even more preferably between 20° and 70°, which improves the accuracy of the chronometric test in both horizontal and vertical positions. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic isometric view of a non-limiting embodiment of a tourbillon mechanism according to the invention in a static state. [Figure 2] FIG. 1 is a schematic isometric view of a non-limiting embodiment of a tourbillon mechanism according to the invention in a static state. [Figure 3] FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. [Figure 4] FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. [Figure 5] FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. [Figure 6] FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. [Figure 7] FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. [Figure 8] FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. [Figure 9]FIG. 3 is a schematic plan view showing the operating sequence of the mechanism shown in FIGS. 1 and 2, with the balance and base omitted. Embodiments of the invention

[0019] Further details of the invention will become apparent from the following description taken in conjunction with the accompanying drawings.

[0020] 1 and 2 show a schematic representation of a tourbillon mechanism 1 according to the invention, the term "tourbillon" being interpreted in a broad sense. The mechanism 1 comprises a rotary support 3, which is pivotally mounted on a base 5 about a first axis of rotation A1 and which is adapted to be rotated by a drive source S, such as a mainspring housed in a barrel in a known manner. The drive source S is shown diagrammatically in FIG. 1, with the kinematic linkage for rotating the rotary support 3 indicated by the arrow. This kinematic linkage may be in the form of gears, a chain, a belt, or any similar known form.

[0021] 1 and 2, the rotary support 3 is stationary, and the drive source S tends to rotate the rotary support 3 clockwise according to the orientation of the figures, as will become clearer below. In the illustrated embodiment, the rotary support 3 is a plate with bars that are integrally rotatable with the plate. The plate is floatingly supported by suitable bearings, but the rotary support 3 may also be a simple plate, a floating cage, or a cage conventionally pivoted between bearings, or any other suitable structure.

[0022] The base 5 may be attached to or form part of the movement frame, or may be movable if the tourbillon mechanism 1 is designed with two or three axes according to the Richard Goode two- or three-axis tourbillon principle, or the MB&F Legacy Machine Thunderdome principle described in the Background Art section.

[0023] The rotary support 3 carries a balance-hairspring oscillator 7 (the hairspring is not shown, but is arranged to provide a restoring torque to the balance 7, causing it to oscillate in a conventional manner), which is pivotally mounted to the rotary support 3 about a second axis of rotation A2. Of course, other suitable spring shapes known to those skilled in the art (helical, spherical, double spiral, etc.) are also contemplated. This axis A2 may coincide with axis A1 or may be offset from axis A1 as shown. Furthermore, axis A2 may, if desired, not be parallel to axis A1, but may be inclined at an angle of 1° to 90°, preferably 10° to 80°, and more preferably 20° to 70° relative to axis A1.

[0024] Next, regarding the escapement, the escape wheel 9 is coaxial with the axis A1 and is attached to the base 5 so as to rotate integrally.

[0025] As shown in the figure, the escape wheel 9 is hollow at the center and has teeth on the outer periphery, but it may have internal teeth as in Patent Document 1, or may be a crown type with external teeth.

[0026] The key feature of this invention is that the escapement is of the direct impulse type, meaning that at least a portion of the driving force for the oscillator is supplied by cooperation between the escape wheel on the one hand and a structure (such as an impulse pallet) supported on the balance shaft on the other, and does not pass through a component acting as a blocking member (such as a pallet fork, which provides an indirect impulse). A conventional example of an escapement that drives an oscillator purely by direct impulse is the detent escapement, in which the escape wheel blocking member simply blocks and releases the escape wheel, and the impulse is provided directly with each vibration by cooperation between the escape wheel teeth and the impulse pallet attached to the balance shaft in integral rotation. An conventional example of an indirect impulse escapement is the Swiss anchor escapement, in which the pallet fork serves as both a blocking and impulse transmitting component, and the impulse generated by cooperation between the tip of the escape wheel teeth and the slope of the pallet is transmitted to the impulse pin via a lever and then provided to the oscillator. Finally, an example of a "hybrid" direct impulse escapement, combining both direct and indirect impulse, is the Omega-Daniels Co-Axial escapement, where the impulse is provided in one direction by the escape wheel and impulse pallet working together, similar to a detent escapement, and in the other direction by the anchor.

[0027] As described above, in the tourbillon mechanism 1 of the present invention, which is a direct impulse tourbillon mechanism, the rotary support 3 carries, for this purpose, a detent lever 11 as a blocking member, which is pivotally mounted to the rotary support 3 about a third axis of rotation A3. A blocking pallet 11a is provided near or at a first end of the detent lever 11, which cooperates with the teeth of the escape wheel 9 to block and release the rotation of the rotary support 3. As shown in FIGS. 1 and 2, a restoring force F is applied which tends to engage the blocking pallet 11a with the teeth of the escape wheel 9. This force F may be applied by an appropriate elastic member, or the detent lever 11 may cooperate directly with the teeth of the escape wheel 9 without the pallet 11a. A first stopper 12 attached to the rotary support 3 limits the rotation of the detent lever 11 and limits its maximum position under the action of the restoring force F.

[0028] The other end of the detent lever 11 is provided with a retractable finger 11b, which cooperates with a release pallet 13. The release pallet 13 is arranged to rotate integrally with the balance 7. The angle of the end of the release pallet may be parallel to the second axis of rotation A2, parallel to the first axis of rotation A1 in the position where it cooperates with the retractable finger 11b, or may have an intermediate angle or a convex shape. Furthermore, the release pallet 13 may have any other suitable shape, such as a finger, a pin, or any other element that performs this function.

[0029] The retractable finger 11b is pivotally attached to the detent lever 11 so as to rotate about a fourth rotation axis A4, and a restoring force is applied by the elastic member 14 so that the retractable finger 11b abuts against the stopper 11c. As a result, when the release pallet 13 rotates in a first direction (counterclockwise as viewed in the figure) in cooperation with the retractable finger 11b, the detent lever 11 is rotated, and the blocking pallet 11a is separated from the teeth of the escape wheel 9. When the release pallet 13 cooperates with the retractable finger 11b in the other direction (clockwise), the retractable finger 11b rotates relative to the detent lever 11 against the action of the elastic member 14, allowing the release pallet 13 to pass.

[0030] To provide impulses to the balance 7, an impulse pallet 15 is also provided, which is arranged to rotate integrally with the balance 7 and is arranged to cooperate directly with the teeth of the escape wheel 9 when the rotary support 3 rotates. When the rotary support 3 is stationary (as in Figures 1 and 2), the teeth of the escape wheel 9 are outside the reach of the impulse pallet 15 and there is no interaction between these elements.

[0031] Although a detent system is illustrated in the drawings, other types of direct impulse escapements are also conceivable. For this purpose, it may be possible to combine a Swiss lever escapement (which functions as a shutoff member and provides an indirect impulse to the balance 7 in a known manner) with an impulse pallet 15 arranged in integral rotation with the balance 7 and cooperating directly with the escape wheel 9 or with the teeth of an impulse wheel having contralateral or internal teeth on one or the other side and mounted in integral rotation on the escape wheel 9, or with other direct impulse escapements (such as the Omega-Daniels escapement) suitable for modification to include a fixed escape wheel 9. Furthermore, the shutoff member 11 may be a cam or other suitable element.

[0032] The operational sequence of the tourbillon 1 according to the present invention will now be described with reference to FIGS.

[0033] For reassurance, in the state shown in Figures 1 and 2, the rotary support 3 is stationary and the blocking pallet 11a is in contact with the teeth of the escape wheel 9. The balance 7 is rotating counterclockwise and the release pallet 13 is in contact with the second end 11b of the detent lever 11.

[0034] 3, the release pallet 13 begins to cooperate with the retractable finger 11b, causing the detent lever 11 to rotate about its axis of rotation A3 and lifting the blocking pallet 11a to pass over the teeth of the escape wheel 9. At the same time, the impulse pallet 15 enters the circle defined by the teeth of the escape wheel 9.

[0035] In Figure 4, the release pallet 13 lifts the detent lever 11, the blocking pallet 11a separates from the teeth of the escape wheel 9, and the rotary support 3 begins to rotate clockwise, whereby the impulse pallet 15 comes into contact with the teeth of the escape wheel 9 and receives an impulse from these teeth.

[0036] With further rotation, as shown in FIG. 5, the release pallet 13 no longer cooperates with the retractable finger 11b and the restoring force F begins to rotate the detent lever 11 counterclockwise about its axis of rotation A3.

[0037] In Figure 6, the detent lever 11 returns to its initial position relative to the rotary support 3 under the action of the restoring force F and again enters the teeth of the escape wheel 9. Its angular position relative to the rotary support 3 is determined by the first stopper 12 against which the detent lever 11 abuts.

[0038] As shown in FIG. 7, the rotary support 3 continues to rotate clockwise under the action of the driving source.

[0039] Figure 8 shows the state in which the rotary support 3 is again stationary and the blocking pallet 11a is now in contact with the next tooth of the escape wheel 9. The balance 7 has finished its counterclockwise oscillation and can begin its clockwise oscillation.

[0040] 9, when the release pallet 13 comes into contact with the retractable finger 11b, the retractable finger 11b is lifted against the force of the elastic member 14. The first stopper 12 is long enough to cooperate with the detent lever 11 but does not reach the retractable finger 11b, so that the retractable finger 11b does not rotate about its rotation axis A4 to prevent the release pallet 13 from passing through.

[0041] This cycle of operation is repeated.

[0042] Regarding materials, all materials used in modern watchmaking can be considered (metals, non-metals such as silicon, silicon compounds, synthetic diamond, sapphire, structurable glasses, ceramics, glass-ceramics, metallic glasses, polymers, composites, materials suitable for additive manufacturing, etc.).

[0043] The detent lever 11 may also be formed integrally with an elastic member that exerts the restoring force F. Furthermore, the detent lever 11 (or more generally the blocking element, which may, note, also be a lever, etc.) may be supported on the rotary support 3 by a flexible pivot system, in which case the axis of rotation A3 is virtual and is determined by the flexible pivot. More generally, an embodiment using a flexible pivot makes it possible to omit the first stop 12, for example if the first stop 12 is integrated into the detent lever with the flexible pivot, and also makes it possible for at least some axes to be virtual rather than physical.

[0044] There is no limitation on the shape and arrangement of each element as long as the above-mentioned functions are achieved.

[0045] This description is provided as a non-limiting example of the present invention, and those skilled in the art can make additions to the scope of the invention, which is defined by the claims, without departing from the scope thereof.

Claims

1. a rotary support (3) pivotally mounted on a base (5) so as to be rotatable about a first rotation axis (A1) and configured to be rotated by a drive source (S); a vibrator (7) pivotally mounted on the rotary support (3) so as to be rotatable about a second rotation axis (A2); an isolation member (11) attached to the rotary support (3) and configured to isolate and release the rotation of the rotary support (3) by being controlled by the rotation of the vibrator (7); an escape wheel (9) attached to the base (5) so as to rotate integrally with the base (5) and configured to cooperate with the blocking member (11); a direct impulse member (15) attached to the second rotation axis (A2) and configured to cooperate with the escape wheel (9) to impart an impulse to the oscillator (7) during rotation of the rotary support (3); A tourbillon mechanism (1) for a watch movement, comprising:

2. 2. A tourbillon mechanism (1) according to claim 1, wherein the blocking member (11) is a detent lever (11) pivotally mounted on the rotary support (3) so as to be rotatable about a third axis of rotation (A3) and adapted to cooperate with a release pallet (13) mounted on the second axis of rotation in order to rotate the detent lever (11) and thereby initiate rotation of the rotary support (3), the detent lever (11) being subjected to a restoring force (F) tending to remain engaged with the escape wheel (9).

3. 3. A tourbillon mechanism (1) according to claim 2, characterized in that the detent lever (11) is provided with a retractable finger (11b) which is mounted to rotate about a fourth axis of rotation (A4) and which cooperates with the release pallet (13) to rotate the detent lever (11) and initiate rotation of the rotary support (3) during a first oscillation of the oscillator (7) and which retracts to allow the release pallet (11b) to pass during a second oscillation of the oscillator (7).

4. 4. A tourbillon mechanism (1) according to claim 3, wherein the retractable finger (11b) is subjected to a restoring force exerted by an elastic member (14) which tends to maintain the retractable finger (11b) in abutment against a stopper (11c) carried by the detent lever (11).

5. 2. A tourbillon mechanism (1) according to claim 1, wherein the blocking member (11) is an anchor.

6. Tourbillon mechanism (1) according to any one of claims 1 to 5, wherein said second axis of rotation (A2) is different from said first axis of rotation (A1).

7. 7. A tourbillon mechanism (1) according to any one of the preceding claims, wherein the second axis of rotation (A2) forms an angle with the first axis of rotation (A1) of between 1° and 90°, preferably between 10° and 80°, and even more preferably between 20° and 70°.

8. A timepiece movement comprising a tourbillon mechanism (1) according to any one of claims 1 to 7.

9. A timepiece comprising the movement according to claim 8.

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