Timepiece adjusting member comprising actuation system provided with eccentric device

Abstract

The invention relates to an adjustment member (1) for a timepiece movement, comprising an inertial mass such as a balance (23), a balance spring (25) comprising a winding band (2) and means (30) for adjusting the stiffness of the balance spring, a balance clip (22) and an actuation system (20) for adjusting the rate of the balance spring (25), the means being provided with an elastic element (5) arranged in series with the winding band (2), the adjustment device (30) comprises prestressing means (6) for applying a variable force or torque to the flexible element (5), and the actuation system (20) comprises eccentric means for actuating the prestressing means (6) of the adjustment device (30).

Description

Technical Field

[0001] The present invention relates to the field of watchmaking and more particularly to the field of mechanical watchmaking in which the drive energy is regulated by a regulating member. More specifically, the present invention relates to a regulating member provided with a fine actuation system for adjusting the rate of a balance spring, a timepiece movement comprising such a regulating member, and a timepiece comprising such a timepiece movement. Background Art

[0002] In most mechanical watches, the energy required to rotate the hands (such as the minute and hour hands) is stored in a barrel and then transferred by a balance system with a balance spring, which consists of a flywheel called a balance wheel, combined with a balance spring in the form of a spirally wound band called a balance spring.

[0003] The inner end of the balance-spring is attached to a shaft that rotates integrally with the balance wheel; the outer end of the balance-spring is attached to a pin mounted on a pin-holder, which is itself rigidly connected to a stationary bridge.

[0004] The rotation of the balance wheel is maintained and its oscillations are counted by an escapement mechanism comprising a pallet-lever excited by a low-amplitude oscillating motion, provided with two pallet forks which engage the teeth of the escape wheel. When the escape wheel is engaged in this way, it is caused to rotate in steps, the frequency of which is determined by the oscillation frequency of the pallet-lever, which itself is set to the oscillation frequency of the balance wheel with balance spring.

[0005] In a conventional escapement, the oscillation frequency is about 4 Hz, or about 28,800 vibrations per hour (V / h). One of the goals of a good watchmaker is to ensure the isochronism and regularity (or constancy of rate) of the oscillations of the balance wheel.

[0006] The rate of the balance-spring can be adjusted in a known manner by adjusting its effective length, defined as the length of the curve between its inner end and a counting point situated near its outer end and usually defined by a pair of flanges carried by a key mounted on an index system.

[0007] In operation, this pointer system cannot rotate about the axis of the balance spring. However, its angular position can be fine-tuned by manual intervention, for example by pivoting an eccentric device acting as a cam on the pointer system using a screwdriver.

[0008] The assembly comprising the bridge, pointer system, key, pin holder, pin, shaft, hairspring and balance wheel is generally referred to as a "regulating member". Examples of regulating members are given in European Patent EP3304215 and European Patent EP 2876504, both of which were applied for by watch manufacturer ETA.

[0009] There are pointer systems that have a pin holder to which the outer end of the balance spring is attached and in which the pointer system key has a clearance to allow the balance spring to move between the two convex edges. However, the timing properties, especially the non-isochronism, are very sensitive to the clearance at the pointer key and it is difficult to control this clearance accurately.

[0010] In some devices, the collar can be adjusted to clamp the balance spring so as to eliminate play, especially when the balance spring is operating. In this case, the rate is first adjusted by moving the pointer key, and then the balance spring is clamped to this key. However, clamping the balance spring to the pointer key carries the risk of stressing it and generating timing errors, especially due to the winding device being off-center. Moreover, removing the play also changes the rate, and once the balance spring has been clamped, it is not possible to move the pointer key along the balance spring to achieve fine adjustment of the rate.

[0011] Other balance springs have an integrated regulating device. In these balance springs, the rate is adjusted not by varying the effective length of the balance spring, but by applying a force or torque to an elastic element arranged in series with the balance spring. In this way, the stiffness of the elastic element and therefore of the entire balance spring can be modified. Adjusting the stiffness of the balance spring allows adjusting the rate of the regulating member. Such a balance spring provided with an elastic element is described, for example, in patent application EP4009115.

[0012] However, in these cases, it is not possible to use the usual pointer system, since it is incompatible with the balance-spring regulating device. Moreover, since the rate must be regulated to a very fine degree, there must be no play between the balance-spring and the area where it interacts with the pointer mechanism. More specifically, if this is not the case, there is a risk of changing the rate in the event of a shock if the balance-spring does not reposition itself in exactly the same way after receiving it. Summary of the invention

[0013] The object of the present invention is to overcome some or all of the above-mentioned disadvantages by providing an actuation system that is compatible in particular with regulating devices of this type.

[0014] To this end, the invention relates to a regulating member for a timepiece movement, comprising an inertial mass such as a balance, a balance spring, a balance cock and an actuation system for adjusting the rate of the regulating member, the balance spring comprising a winding band and a device for adjusting the stiffness of the balance spring provided with an elastic element arranged in series with the winding band, the adjustment device comprising prestressing means for applying a variable force or torque to the flexible element.

[0015] The invention is characterized in that the actuation system comprises an eccentric device of the prestressing device of the actuation adjustment device.

[0016] Thanks to the invention, it is possible to adjust the speed of the adjusting member simply by changing the position of the eccentric device which acts on the prestressing device to adjust the speed of the adjusting member.

[0017] In a particular embodiment of the invention, the eccentric is arranged through the balance bridge, whereby it is rotatably mounted.

[0018] In a particular embodiment of the invention, the eccentric device includes a head and a body extending from the head.

[0019] In a particular embodiment of the invention, the body comprises a finger extending from the body, the finger being off-centre relative to the main axis of the body of the eccentric.

[0020] In a particular embodiment of the invention, the head comprises a recess intended to receive the tip of a tool for actuating the eccentric.

[0021] In a particular embodiment of the invention, the prestressing means comprises a first movable lever connected to the flexible element, wherein the eccentric means is in direct or indirect contact with the first lever so as to be able to actuate the first lever.

[0022] In a particular embodiment of the invention, the prestressing means comprises a second movable lever connected to the flexible element, wherein the eccentric means is in direct or indirect contact with the second lever so as to be able to actuate the second lever.

[0023] In a particular embodiment of the invention, the prestressing device comprises a movable body connected to the first operating lever and / or the second operating lever, wherein the finger is in contact with the movable body so as to be able to move the movable body.

[0024] In a particular embodiment of the invention, the finger comprises a peripheral groove cooperating with the movable body.

[0025] In a particular embodiment of the invention, the actuation system comprises a pin-holder including a pin on which the balance-spring is mounted, the pin being mechanically coupled to the elastic element of the balance-spring.

[0026] In a particular embodiment of the invention, the latch is mechanically coupled to the elastic element.

[0027] In a particular embodiment of the invention, the pin-holder is arranged on the balance bridge around a bearing on the balance staff.

[0028] The invention also relates to a timepiece movement comprising such a regulating member.

[0029] The invention also relates to a timepiece, such as a wristwatch, comprising such a timepiece movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The objects, advantages and features of the present invention will become apparent after reading several embodiments given with reference to the accompanying drawings, which are provided for illustrative purposes only and are not intended to limit the scope of the invention, in which:

[0031] Figure 1 A top view of an adjusting member according to a first embodiment of the invention is shown diagrammatically,

[0032] Figure 2 Shown diagrammatically Figure 1 A bottom view of a first embodiment of an adjusting member shown in FIG.

[0033] Figure 3 Shown diagrammatically Figure 1 A sectional side view of the first embodiment of the adjusting member shown in FIG. 1 taken along the section line III,

[0034] Figure 4 Shown diagrammatically Figure 1 A perspective exploded view of a first embodiment of an adjustment member is shown in FIG.

[0035] Figure 5 Shown diagrammatically Figure 1 Top view of a balance spring of a first embodiment of a regulating member shown in FIG. DETAILED DESCRIPTION

[0036] Figures 1 to 5 A first embodiment of a regulating member 1 intended to be arranged in a timepiece movement not shown in the drawings is diagrammatically shown. Such a timepiece movement comprises, for example, a plate provided with a recess for receiving said regulating member 1, provided with an inertial mass and an elastic return element for this inertial mass, configured to cause it to oscillate.

[0037] Regulating member 1 also comprises an actuation system 20 , an annular balance 23 as inertial mass, a balance stem 24 , a balance spring 25 as elastic return element and a balance bridge 22 .

[0038] exist Figures 1 to 3 2 , balance wheel 23 , balance spring 25 , balance cock 22 and actuating system 20 are stacked together, in this case from bottom to top.

[0039] The balance shaft 24 is centered and passes through the center of the balance 23, the center of the balance spring 25 and the balance cock 22. The balance shaft 24 is held by two anti-vibration bearings 28 arranged at both ends of the balance shaft 24. A first bearing (not shown in the drawings) is arranged below the balance 23 and the balance cock 22, while a second bearing 28 is held by the balance cock 22. The balance cock 22 has a hole, in this case a through hole, inside which the second bearing 28 is held. The actuation system 20 is mounted on the balance cock 22 and, in this embodiment, is arranged along the central axis of the balance shaft 24.

[0040] Figure 5 An example of a balance spring 25 is shown which preferably extends substantially in one plane. The balance spring 25 comprises a flexible band 2 wound several times around itself, the band 2 having a predefined stiffness. The inner end 9 of the band 2 is integral or assembled with a support 3, usually called a collet. The support 3 is generally triangular in shape and is fitted around the shaft of the balance 24.

[0041] Balance-spring 25 also comprises means 30 for adjusting its stiffness. Adjustment means 30 may be actuated in particular by a user, for example when this regulating member is mounted on a plate of a timepiece movement.

[0042] The adjustment device 30 comprises a flexible element 5 arranged in series with the belt 2, wherein the flexible element 5 connects one end 4 of said belt 2 to a fixed support 53 and is integral with one end 4 of the belt 2. The flexible element 5 is integral with the outer end 4 of the belt 2. The elastic element 5 is an element distinct from the belt 2.

[0043] The flexible element 5 adds additional stiffness to the stiffness of the belt 2. The flexible element 5 is preferably stiffer than the belt 2. In this case, the flexible element 5 is arranged as an extension of the belt 2. Preferably, the adjustment device and the belt 2 are integral, or even made of the same material, such as silicon.

[0044] In this embodiment of a balance spring, flexible element 5 comprises two flexible parts 15 , 16 each connecting band 2 to a fixed support 53 .

[0045] The two flexible parts 15, 16 are arranged axisymmetrically with respect to one another along the axis A of the balance spring 25. In other words, the two flexible parts 15, 16 are positioned symmetrically with respect to said axis A.

[0046] On the one hand, axis A passes substantially through the centre O of the balance spring; on the other hand, axis A preferably passes through the outer end 4 of strap 2 .

[0047] Thus, the two flexible parts 15 , 16 are arranged on the periphery of the balance spring in such a way that the two flexible parts 15 , 16 are arranged at the same distance from the centre O of the balance spring 25 .

[0048] The two flexible parts 15, 16 are preferably arranged in a "mirror" position relative to each other with respect to the axis A. For this purpose, the two flexible parts 15, 16 are preferably substantially identical.

[0049] The flexible parts 15, 16 each comprise a curved flexible strip 55, preferably forming a semicircle, and extending from the end of the fixed support 53. Each curved flexible strip 55 is also connected to the outer end 4 of the belt 2 by a main flexible strip 7. In this case, the main flexible strips 7 are arranged continuously to each other.

[0050] The fixed support 53 has an open trapezoidal shape on the long sides facing the outer end 4 of the belt 2 .

[0051] The device for adjusting the balance spring 25 also comprises a prestressing device 6 for applying a variable force or torque to the flexible element 5. In this way, the stiffness of the balance spring can be adjusted. Thanks to the prestressing device 6, this torque or force can be adjusted continuously. In other words, this torque or force is not limited to an isolated value. Therefore, the stiffness of the flexible element 5 can be adjusted very accurately.

[0052] Preferably, the prestressing means 6 applies substantially the same force or torque to each flexible member 15, 16. The directions of the forces are preferably substantially symmetrical with respect to the axis A.

[0053] The prestressing device 6 also comprises two levers 14, 26 each connecting the curved strip 55 to the same movable body 19, which is arranged on the other side of the balance spring 25 relative to the fixed support 53. In this case, the movable body 19 is hook-shaped.

[0054] The variable force or torque is applied to the movable body 19. The variable force or torque is at least partially transmitted via the lever 26 to the main flexible strip 7 of the flexible part 15, 16 of the flexible element 5.

[0055] exist Figures 1 to 4 In the embodiment shown in FIG. 8 , the actuation system 20 is equipped with a latching pin holder 31 provided with a latching pin 34 .

[0056] The pin holder 31 is in contact with the balance bridge 22 , and is held and positioned by the shock absorber 28 .

[0057] During operation of regulating member 1 , pin-holder 31 is preferably immobile relative to balance-cock 22 .

[0058] The key retainer 31 includes a central ring 38 arranged around the second bearing 28 .

[0059] The latching pin holder 31 comprises a projection 41 extending radially from the central ring 38 , which projection 41 presses the latching pin 34 by means of a screw 74 .

[0060] Pin 34 cooperates with fixed support 53 of elastic element 57. Elastic element 5 is thus retained by the pin. Balance spring 25 is retained on the one hand by elastic element 5 and on the other hand by support 3.

[0061] The prestressing device 6 is also supported by the key holder 31 .

[0062] The pin and balance spring 25 are assembled together, for example, by bonding, brazing, welding, by deformation of metallic glass or by mechanical fastening.

[0063] In order to be able to apply this variable force or torque to balance-spring 25 , this regulating member comprises an actuation system 20 .

[0064] According to the invention, actuation system 20 comprises a rotatable eccentric 10 which cooperates with balance-spring 25 to modify its stiffness.

[0065] The eccentric 10 comprises a head 21 provided with a recess 18 for receiving the tip of a tool for adjusting the eccentric 10. The eccentric 10 has a body 11 extending from the head 21, the body 11 being preferably cylindrical.

[0066] The eccentric 10 further comprises a finger 12 which is offset relative to the main axis of the body 11 of the eccentric 10. The finger 12 extends from the body 11. The finger 12 is mechanically coupled to the prestressing device 6 but does not block the belt 2.

[0067] The eccentric 10 is arranged to pass through a balance cock 22. The balance cock 22 comprises a flared through hole 17 so as to retain the head 21 of the eccentric 10 and to allow the body 11 and the finger 12 to pass to the other side of the balance cock 22.

[0068] Eccentric 10 is held by a clamp 29 clamped around body 11 of eccentric 10 beneath balance cock 22 .

[0069] Preferably, the body 11 comprises a groove 32 into which the clamp 29 is inserted in order to retain the eccentric 10 in the hole 17 .

[0070] The eccentric 10 is rotatably mounted in the balance cock 22 . It can therefore rotate in the hole 17 and the clamp 29 about the main axis of the eccentric 10 , preferably substantially perpendicular to the balance cock 22 and / or substantially parallel to the balance staff 24 .

[0071] The finger 12 of the eccentric 10 is in contact with the movable body 19 of the prestressing device 6 so as to be able to push the lever 14 , 26 more or less hard when the eccentric 10 is rotated.

[0072] Preferably, finger 12 comprises a peripheral groove 33 cooperating with movable body 19 of balance-spring 25 , movable body 19 being inserted into groove 33 .

[0073] Thus, when the eccentric 10 rotates, the finger 12 presses more or less against the movable body 19 , since it is eccentric with respect to the main axis of rotation of the eccentric 10 .

[0074] The movement of the finger 12 relative to this movable body modifies the stiffness of the elastic element 5, since it exerts a greater or lesser force or torque on the movable body 19 of the prestressing device 6, causing the stiffness of the flexible parts 15, 16 of the elastic element 5 to vary via the lever 26, and therefore also the overall stiffness of the balance spring 25. Thus, the actuation system 20 allows the rate of said regulating member 1 to be adjusted.

[0075] For this purpose, the actuation system 20 can be used to modify the position of the finger 12 .

[0076] Actuation system 20 is configured to adjust the rate of regulating member 1 with a resolution less than or equal to 1 sec / day, preferably less than or equal to 0.5 sec / day, or even less than or equal to 0.1 sec / day. The configuration of regulating member 1 allows such precision to be achieved.

[0077] It goes without saying that the invention is not limited to the embodiments of the adjustment member described with reference to the figures and that alternatives may be considered without departing from the scope of the invention.

Claims

1. A regulating member (1) for a watch movement, comprising an inertial mass such as a balance (23), a balance spring (25), a balance cock (22) and an actuating system (20) for adjusting the rate of the balance spring (25), the balance spring (25) comprising a winding band (2) and means (30) for adjusting the stiffness of the balance spring, the means being provided with an elastic element (5) arranged in series with the winding band (2), the regulating means (30) comprising prestressing means (6) for applying a variable force or torque to the flexible element (5), characterised in that The actuation system (20) comprises an eccentric device (10) for actuating a prestressing device (6) of the adjustment device (30).

2. The adjusting member according to claim 1, characterized in that: The eccentric device (10) is rotatably mounted through the balance wheel bridge (22).

3. The adjusting member according to claim 1 or 2, characterized in that: The eccentric device (10) comprises a head (21) and a body (11) extending from the head (21).

4. The adjusting member according to claim 3, characterized in that: The eccentric device (10) further comprises a finger (12) extending from the body (11), the finger (12) being offset relative to the main axis of the body (11) of the eccentric device (10).

5. The adjusting member according to claim 3 or 4, characterized in that: The head (21) comprises a recess (18) intended to receive the tip of a tool for actuating the eccentric (10).

6. Adjustment member according to any one of the preceding claims, characterized in that The prestressing device (6) comprises a movable first lever (14) connected to the flexible element (5), wherein the eccentric device (10) is in direct or indirect contact with the lever (14) so ​​as to be able to actuate the lever (14).

7. The adjusting member according to claim 6, characterized in that: The prestressing device (6) comprises a second movable lever connected to the flexible element (5), wherein the eccentric device (10) is in direct or indirect contact with the second lever (26) so as to be able to actuate the second lever (26).

8. The adjusting member according to claim 6 or 7, characterized in that: The prestressing device (6) comprises a movable body (19) connected to the first operating lever (14) and / or the second operating lever (26), wherein the finger (12) is in contact with the movable body (19).

9. The adjusting member according to claim 8, characterized in that: The finger (12) comprises a peripheral groove (33) cooperating with the movable body (19).

10. An adjustment member according to any one of the preceding claims, characterized in that The actuation system (20) comprises a pin holder (31) comprising a pin (34) on which the balance spring (25) is mounted, the pin (34) being mechanically coupled to the elastic element (5) of the balance spring (25).

11. An adjustment member according to any one of the preceding claims, characterized in that The pin holder (31) is arranged on the balance bridge (22) around a bearing (28) on the balance shaft (24).

12. A watch movement, characterized in that: The timepiece movement comprises a regulating member ( 1 ) according to any one of the preceding claims.

13. A timepiece, such as a watch, characterized in that: The timepiece comprises a timepiece movement according to claim 12 .

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