Timepiece speed regulation mechanism comprising improved fast and slow hand system

Abstract

The invention relates to a speed regulating mechanism (1) for a timepiece movement, comprising an inertial mass body such as a balance wheel (23), a balance spring (25), a balance plate (22), and a fast / slow pointer system (20) for regulating the travel time difference of the balance spring (25), said fast / slow pointer system (20) comprising a stud holder (31) comprising a first stud (34) on which the balance spring (25) is mounted, the speed regulating mechanism is characterized in that the swing clamping plate (33) comprises a second outer pile, the balance spring (25) is also installed on the second outer pile, and the outer pile maintaining piece (31) can rotate relative to the swing clamping plate (33) so that the travel time difference of the speed regulating mechanism (1) can be adjusted.

Description

Technical Field

[0001] The present invention relates to the field of watchmaking, more specifically to the field of mechanical watchmaking, in which the regulation of the drive energy is provided by a speed regulating mechanism. More specifically, the present invention relates to a speed regulating mechanism provided with a precise index system, a watch movement including such a speed regulating mechanism and a watch including such a watch 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 transmitted by a balance-sprung system consisting of a flywheel called a balance combined with a spring in the form of a spirally wound strip called a hairspring.

[0003] The inner end of the balance spring is attached to a balance staff that rotates integrally with the balance wheel; the outer end of the balance spring is attached to a stud mounted on a stud 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 the escapement, which consists of a pallet fork performing a low-amplitude oscillating motion, provided with two pallets that engage with the teeth of the escape wheel. When the escape wheel is engaged in this way, it causes the escape wheel to rotate in steps, the frequency of which is determined by the oscillation frequency of the pallet fork, which itself is set to the oscillation frequency of the balance-sprung system.

[0005] In a traditional 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 of the balance wheel's oscillations (or the constancy of its running time).

[0006] The balance's run-time can be adjusted in a known manner by adjusting the effective length of the balance spring, defined as the length of the curve between the inner end of the balance spring and a counting point, located near the outer end of the balance spring and usually defined by a pair of stops carried by a key mounted on the regulator system.

[0007] In operation, the regulator index cannot rotate about the axis of the balance spring. However, its angular position can be adjusted by manual intervention, for example using a screwdriver to pivot an eccentric on the regulator index that acts like a cam.

[0008] The assembly including the bridge, index system, key, stud holder, stud, balance staff, hairspring and balance wheel is generally referred to as the "regulating mechanism". Examples of regulating mechanisms are given in European Patent EP3304215 and European Patent EP2876504, both filed by watch manufacturer ETA.

[0009] With some regulator systems, the outer end of the balance spring is attached to its stud holder, and the regulator key has play to allow the balance spring to move between two stops. However, the chronometric characteristics, especially the anisochronism, are very sensitive to the play at the regulator key, and this play is difficult to control accurately.

[0010] In some devices, these stops can be adjusted to clamp the balance spring in order to eliminate play, especially when the balance spring is running. In this case, the balance spring is first adjusted by moving the regulator key, and then the balance spring is clamped to the key. However, clamping the balance spring to the regulator key may stress the balance spring and produce timing errors, especially due to the winding being off-center. Moreover, eliminating play will also change the balance spring, and once the balance spring is clamped, it is no longer possible to move the regulator key along the balance spring to achieve fine adjustment of the balance spring.

[0011] Other hairsprings have an integrated speed regulating device. In these hairsprings, the running time is not regulated by changing the effective length of the hairspring, but by applying a force or torque to a flexible element arranged in series with the hairspring. In this way, the stiffness of the flexible element and thus of the hairspring as a whole can be varied. By adjusting the stiffness of the hairspring, the running time of the speed regulating mechanism can be adjusted. Such a hairspring provided with a flexible element is described, for example, in patent application EP4009115.

[0012] However, in these cases, the usual regulator systems cannot be used, as they are incompatible with the balance spring. Moreover, since the error must be regulated to a very precise degree, it is important that there is no play between the balance spring and the area where it interacts with the regulator mechanism. More specifically, if this were not the case, the error could change in the event of a shock if the balance spring did not reposition itself in exactly the same way after the shock. Summary of the invention

[0013] The object of the present invention is to overcome some or all of the above-mentioned disadvantages by providing a regulator system that is compatible with such adjustment devices.

[0014] To this end, the present invention relates to a speed regulating mechanism for a watch movement, the speed regulating mechanism comprising an inertial mass body such as a balance wheel, a hairspring, a balance plate, and a speed needle system for adjusting the travel time difference of the speed regulating mechanism, the speed needle system comprising an external pile holder, the external pile holder comprising a first external pile, and the hairspring is mounted on the first external pile.

[0015] The present invention is characterized in that the balance cock comprises a second stud, the hairspring is also mounted on the second stud, and the stud holder can rotate relative to the balance cock to adjust the travel time difference of the speed regulating mechanism.

[0016] Thanks to the invention, the regulation of the regulating organ can be adjusted simply by changing the position of the stud holder, since this changes the position of the first stud relative to the second stud, which remains immobile relative to the plate. The stiffness of the balance spring changes, since it is carried by both studs. The guide markings remain unchanged, since the position of the second stud does not change.

[0017] In a particular embodiment of the invention, the regulator system comprises a return spring exerting an expansion / restoration force between the stud holder and the balance cock.

[0018] In a particular embodiment of the invention, the stud holder is integral with the spring, preferably made of the same material.

[0019] In a particular embodiment of the invention, the regulator needle system comprises a rotatable cam cooperating with the stud holder in order to rotate the stud holder.

[0020] In a particular embodiment of the invention, the stud holder comprises an arm in contact with the cam so that the stud holder can be rotated.

[0021] In a particular embodiment of the invention, the balance spring comprises a wound strip and adjustment means for adjusting the stiffness of the balance spring provided with a flexible element arranged in series with the wound strip, the second stud being mechanically connected to the flexible element.

[0022] In a particular embodiment of the invention, the flexible element is connected to a rigid support, the second stud being integral with the rigid support.

[0023] In a particular embodiment of the invention, the adjustment means comprise prestressing means for applying a variable force or torque to the flexible element, the first stud being mechanically connected to the prestressing means.

[0024] In a particular embodiment of the invention, the flexible element and the prestressing device are arranged between a first stud and a second stud, the first stud being movable relative to the second stud to actuate the prestressing device, the displacement of the first stud relative to the second stud varying the stiffness of the balance spring.

[0025] In a particular embodiment of the invention, the prestressing means comprises a rod connected to the flexible element, the first stud being integral with the free end of the rod.

[0026] In a particular embodiment of the invention, the prestressing means comprises a rigid structure arranged in parallel with the flexible element, to which the rod is connected.

[0027] In a particular embodiment of the invention, the flexible element is connected to a rigid support, the second stud being integral with the rigid support.

[0028] In one particular embodiment of the invention, the stud holder is arranged on the balance cock around a bearing on the balance staff.

[0029] The invention also relates to a timepiece movement comprising such a speed regulating mechanism.

[0030] The invention also relates to a timepiece, such as a wristwatch, comprising such a timepiece movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] 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 present invention, in which:

[0032] - Figure 1 Schematically shows a perspective top view of a speed regulating mechanism according to a first embodiment of the present invention,

[0033] - Figure 2 Schematically shows Figure 1 A perspective top partial exploded view of a first embodiment of the speed regulating mechanism in FIG.

[0034] - Figure 3 Schematically showing a top view of a hairspring of a regulating organ according to the invention,

[0035] - Figure 4 Schematically shows Figure 1 A perspective bottom partial exploded view of a first embodiment of the speed regulating mechanism shown,

[0036] - Figure 5 Schematically shows Figure 1 A bottom view of a first embodiment of a speed regulating mechanism shown in FIG.

[0037] - Figure 6 Schematically shows a perspective top partial view of a speed regulating mechanism according to a second embodiment of the present invention,

[0038] - Figure 7 Schematically shows Figure 6 A partial enlarged view of a portion of a second embodiment of the speed regulating mechanism shown, and

[0039] - Figure 8 Schematically shows Figure 6 A perspective top view of the stud holder of a second embodiment of a regulating organ is shown. DETAILED DESCRIPTION

[0040] Figures 1 to 5A first embodiment of a regulating organ 1 is schematically shown, which is intended to be arranged in a timepiece movement (not shown in the figures). Such a timepiece movement comprises, for example, a plate provided with a recess for receiving the regulating organ 1, the regulating organ 1 being provided with an inertial mass and an elastic return element for the inertial mass, the elastic return element being configured to cause the inertial mass to oscillate.

[0041] The speed regulating mechanism 1 further includes a speed needle system 20 , an annular balance wheel 23 as an inertial mass body, a balance shaft 24 , a hairspring 25 as an elastic reset element, and a balance cock 22 .

[0042] exist Figures 1 to 3 In the embodiment of the present invention, the balance wheel 23, the hairspring 25, the balance bridge 22 and the regulator system 20 are stacked, in this case from bottom to top.

[0043] The balance shaft 24 is located in the center and passes through the center of the balance wheel 23, the hairspring 25 and the balance cock 22. The balance shaft 24 is held by two anti-vibration bearings 28, which are arranged at both ends of the balance shaft 24. A first bearing (not shown in the figure) is arranged below the balance wheel 23 and the balance cock 22, and a second bearing 28 is held by the balance cock 22. The balance cock 22 is provided with a hole, in this case a through hole, in which the second bearing 28 is held. The regulator needle system 20 is mounted on the balance cock 22, and in this embodiment, the regulator needle system 20 is arranged along the central axis of the balance shaft 24.

[0044] Figure 3 An example of a balance spring 25 is shown, which preferably extends substantially in one plane. Balance spring 25 comprises a flexible strip 2 wound several times around itself, with a predetermined stiffness. The inner end 9 of strip 2 is integral or assembled with a support 3, which is usually called a collet. Support 3 is generally triangular in shape and is passed through by balance staff 24.

[0045] Balance spring 25 also comprises an adjustment device for adjusting its stiffness. This adjustment device can be activated in particular by an operator, for example when the regulating organ is mounted on a plate of a timepiece movement.

[0046] The adjustment means comprise a flexible element 5 arranged in series with the strip 2, connecting one end 4 of said strip 2 to a rigid support 17 and being integral with one end 4 of the strip 2. The flexible element 5 is integral with the outer end 4 of the strip 2. The flexible element 5 is an element distinct from the strip 2.

[0047] The flexible element 5 adds additional rigidity to the strip 2. The flexible element 5 is preferably stiffer than the strip 2. In this case, the flexible element 5 is arranged as an extension of the strip 2. Preferably, the adjustment device is integral with the strip 2, or even made of the same material, such as silicon.

[0048] Flexible element 5 of balance spring 25 comprises a pivot with non-intersecting flexible blades. This pivot comprises two non-intersecting flexible blades 11, 12 and a rigid part 18. Flexible blades 11, 12 are connected to rigid support 17 laterally on the one hand and to rigid part 18 by converging towards each other on the other hand. Flexible blades 11, 12 thus preferably extend away from rigid part 18 up to rigid support 17. External end 4 of strap 2 is connected to rigid part 18. Rigid support 17 is immobile relative to the plate. Rigid support 17 is L-shaped, with a first leg 46 of the L serving as connection to flexible blades 11, 12 and a second leg 47 of the L facing away from the pivot with non-intersecting blades so that it can be assembled on a timepiece movement.

[0049] The device for adjusting the balance spring 25 also comprises prestressing means 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 means 6, the torque or force can be adjusted continuously. In other words, the torque or force is not limited to an isolated value. Therefore, the stiffness of the flexible element 5 can be adjusted very accurately.

[0050] The prestressing means 6 comprise a secondary flexible blade 19 arranged on the opposite side of the rigid part 18, in extension of the pivot axis with non-intersecting blades. The secondary flexible blade 19 is arranged at the outer end 4, tangentially to the strip 2.

[0051] The other end of the secondary flexible blade 19 is connected to a curved rod 14, which extends around the strip 2. In addition to the secondary flexible blade 19, the rod 14 is also connected to a rigid structure 27, which is attached to the rigid support 17. When the rod 14 is actuated by a force or torque, the rigid structure 27 is partially deformed.

[0052] Said force or torque is exerted on free end 15 of rod 14. In this way, rod 14 of prestressing device 6 transmits a force or torque to flexible element 5 via secondary flexible blade 19 and rigid structure 27 so as to modify the stiffness of balance spring 25.

[0053] exist Figure 1 and Figure 2 In the present invention, the balance spring 25 has a different configuration. The non-intersecting blades 11, 12, the rigid part 18 and the secondary flexible blade 19 are replaced by a single blade to which the outer end 4 of the rod 14 is attached.

[0054] In order to be able to apply a variable force or torque to balance spring 25 , the regulating organ comprises a regulator system 20 .

[0055] exist Figure 1 , 2In the first embodiment shown in FIGS. 4 and 5 , the speed needle system 20 is equipped with an external pile holder 31 , and the external pile holder 31 is provided with a first external pile 34 .

[0056] According to the invention, balance cock 22 is provided with a second stud 35. Stud holder 31 is mechanically connected to rod 14 of prestressing device 6, but it does not block strap 2.

[0057] Stud holder 31 is in contact with balance cock 22 , and is held and positioned by shock absorber 28 .

[0058] Stud holder 31 is rotatable about the balance shaft relative to balance cock 22 so that it can move first stud 34 and act on lever 14 .

[0059] The stud holder 31 comprises a central ring 38 arranged around the second bearing 28 .

[0060] The stud holder 31 comprises two projections 41, 42 extending radially from the central ring 38. The first projection 41 holds the first stud 34 downward by means of a first screw 74. The second projection 42 holds the second stud 35 downward by means of a second screw.

[0061] In a reference arrangement, first stud 34 and second stud 35 are arranged, for example, substantially symmetrically with respect to balance staff 24 .

[0062] First stud 34 cooperates with free end 15 of lever 14 and second stud 35 cooperates with second leg 47 of rigid support 17. Prestressing device 6 is thus supported by regulator system 20 and flexible element 5 is supported by balance cock 22 from which it is suspended.

[0063] Two studs 34, 35 are arranged on either side of prestressing means 6 and flexible element 5. Furthermore, the two studs 34, 35 are rigidly connected to bar 14 and to rigid support 17. In other words, first stud 34 is integral with bar 14 via free end 15 and second stud 35 is integral with rigid support 17 via second leg 47. These studs are assembled to balance spring 25 by, for example, gluing, soldering, welding, metallic glass deformation or mechanical fastening.

[0064] First stud 34 is movable relative to second stud 35. To this end, stud holder 31 is movable relative to balance cock 22. Stud holder 31 is rotatable about second bearing 28. Thus, first stud 34 moves with stud holder 31, and first stud 34 is rotatable about second bearing 28. First stud 34 can be displaced over an angular range of 20° or even 10°, for example.

[0065] The displacement of the first stud 34 relative to the second stud 35 changes the rigidity of the flexible element 5, because this displacement applies a greater or lesser force or torque to the rod 14 of the prestressing device 6, causing a change in the rigidity of the flexible element 5 and therefore also in the rigidity of the entire balance spring 25. Thus, the regulator system 20 makes it possible to adjust the travel time of the regulating organ 1.

[0066] To this end, regulator system 20 allows the position of first stud 34 to be varied relative to second stud 35. Stud holder 31 moves relative to balance cock 22, with the result that first stud 34 moves relative to second stud 35, in order to vary the force or torque applied to prestressing device 6 of balance spring 25.

[0067] The stud holder 31 of the regulator needle system 20 comprises an arm 63 extending radially outwards in one plane.

[0068] The regulator system 20 comprises a rotatable cam 55 arranged on the balance cock 22. The cam 55 cooperates with the arm 63 of the stud holder 31 to rotate the arm 63 about the second bearing 28. The end 56 of the arm 63 is preferably always in contact with the cam 55, so that the rotation of the cam 55 imparts a movement to the arm 63 according to the angular position of the cam 55. Thus, the stud holder 31 of the regulator system 20 rotates about the second bearing 28. Such a regulator system 20 equipped with the cam 55 allows the stiffness of the balance spring 25 to be linearly varied.

[0069] In order to keep the arm 63 of the stud holder 31 in contact with the cam 55 , the regulator system 20 includes a spring 57 that exerts a restoring force on the stud holder 31 .

[0070] exist Figure 4 , the spring 57 is generally horseshoe-shaped, a first end 58 of the spring is connected to the balance cock 22, and a second end 59 of the spring 57 surrounds a retaining stud 60 extending from the stud holder 31. The spring 57 is arranged in a hollow portion 61 formed in the balance cock 22 below, on the side of the balance wheel 23 and the hairspring 25. The balance cock 22 includes a through hole 62 leading to the hollow portion 61, and the retaining stud 60 extends into the hollow portion 61 through the through hole 62. The through hole 62 is sized to allow the retaining stud 60 to move when the stud holder 31 rotates relative to the balance cock 22.

[0071] Therefore, the spring 57 applies a restoring force to the stud holder 31 of the regulator needle system 20, and the function of this restoring force is to always keep the arm 63 of the stud holder in contact with the cam 55. When the cam 55 is acted upon, the stud holder 31 rotates to move the first stud 34 relative to the second stud 35, while being subjected to the restoring force applied by the spring 57 to allow the arm 63 of the stud holder 31 to contact the cam 55, particularly when the peripheral wall 64 of the cam 55 moves away from the arm 63.

[0072] The regulator system 20 is configured to adjust the rate difference of the regulating organ 1 with a resolution of less than or equal to 1 second per day, preferably less than or equal to 0.5 seconds per day, or even less than or equal to 0.1 seconds per day. The configuration of the regulating organ 1 allows such precision to be achieved.

[0073] The cam 55 is also provided with adjustment marks 49. Thus, in order to adjust the regulator needle system 20, the cam 55 is moved, for example, by means of an adjustment knob (not shown in the figure), which is arranged on the cam 55 and can be rotated. Thus, the cam 55 is oriented according to the preferred guide marks in order to adjust the regulator needle system 20.

[0074] Preferably, the adjustment mark 49 corresponds to the resolution. In other words, the difference between two consecutive guide marks allows the running time difference to change by one second, 0.5 seconds or even 0.1 seconds per day. Figure 6 , adjust the resolution of mark 49 to 0.1 seconds.

[0075] Figures 6 to 8 A second embodiment of a speed regulating mechanism 40 according to the invention is schematically shown. In this embodiment, the stud holder 71 and the spring 72 are integral, preferably made of the same material. In all other respects, the speed regulating mechanism 40 is identical to the first embodiment.

[0076] The stud holder 71 comprises a single protrusion 81 carrying the first stud 34. The stud holder 71 comprises a spring 72 in place of the second protrusion.

[0077] Spring 72 is elongated and extends from ring 77 of stud holder 71 on the side opposite to arm 81. Spring 72 is U-shaped and rests on balance cock 52 when stud holder 71 is mounted in regulating organ 40. A first end 75 of the U is integral with ring 77 of stud holder 71, while a second end 76 is free.

[0078] The second end 76 is inserted into the hole in the swing cock 52. The second free end 76 comprises, for example, a bend 79 for hooking the hole. In this way, the second end 76 of the spring 72 is supported in the hole, thereby locking the spring 72 on this side.

[0079] Thus, when stud holder 71 rotates under the action of the movement of cam 55 , spring 72 is more or less stressed and exerts a restoring force on stud holder 71 so as to keep arm 63 against cam 55 whatever its position.

[0080] Alternatively, second free end 76 may be wedged against edge 78 of balance cock 52 .

[0081] Apart from these differences, regulating organ 40 of the second embodiment has the same features as the first embodiment, in particular with respect to cam 55 , first and second studs 34 , 35 and balance spring 25 .

[0082] This stud holder 71 makes it easier to fit in the regulating organ, since only one component has to be arranged on the balance cock. Storage is also simplified, since a single component replaces two.

[0083] It goes without saying that the invention is not limited to the embodiments of the speed regulating mechanism described with reference to the drawings and that alternatives may be considered without departing from the scope of the invention.

Claims

1. A speed regulating mechanism (1, 40) for a watch movement, the speed regulating mechanism comprising an inertial mass body such as a balance wheel (23), a hairspring (25), a balance plate (22), and a speed needle system (20) for adjusting the travel time difference of the hairspring (25), the speed needle system (20) comprising an external pile holder (31, 71), the external pile holder comprising a first external pile (34), the hairspring (25) being mounted on the first external pile, characterized in that: The balance cock (33, 53) comprises a second stud, the hairspring (25) is also mounted on the second stud, and the stud holder (31, 71) can rotate relative to the balance cock (22, 52) to adjust the travel time difference of the speed regulating mechanism (1, 40).

2. The speed regulating mechanism according to claim 1, characterized in that: The balance spring (25) comprises a wound strip (2) and an adjustment device for adjusting the stiffness of the balance spring, the adjustment device being provided with a flexible element (5) arranged in series with the wound strip (2), the second stud (35) being mechanically connected to the flexible element (5).

3. The speed regulating mechanism according to claim 2, characterized in that: The adjustment device comprises prestressing means (6) for applying a variable force or torque to the flexible element (5), the first stud (34) being mechanically connected to the prestressing means (6).

4. The speed regulating mechanism according to claim 3, characterized in that: The flexible element (5) and the prestressing device (6) are arranged between the first stud (34) and the second stud (35), the first stud (34) being movable relative to the second stud (35) in order to actuate the prestressing device (6), the displacement of the first stud (34) relative to the second stud (35) varying the stiffness of the balance spring (25).

5. The speed regulating mechanism according to claim 4, characterized in that: The prestressing device (6) comprises a rod (14) connected to the flexible element (5), the first stud being integral with a free end (15) of the rod (14).

6. The speed regulating mechanism according to any one of claims 3 to 5, characterized in that: The prestressing device (6) comprises a rigid structure arranged in parallel with the flexible element (5), and the rod (14) is connected to the rigid structure.

7. The speed regulating mechanism according to any one of claims 2 to 6, characterized in that: The flexible element (5) is connected to a rigid support (17) and the second stud (35) is integral with the rigid support (17).

8. A speed regulating mechanism according to any one of the preceding claims, characterized in that: The regulator needle system (20, 60) comprises a rotatable cam (55), wherein the cam (55) cooperates with the stud holder (31, 71) to rotate the stud holder.

9. The speed regulating mechanism according to claim 8, characterized in that: The stud holder (31, 71) comprises an arm (63) in contact with the cam so as to enable the stud holder to rotate.

10. A speed regulating mechanism according to any one of the preceding claims, characterized in that: The regulator needle system (20, 60) comprises a return spring (57, 72) which applies an expansion force between the stud holder (31, 71) and the balance cock (22, 52).

11. The speed regulating mechanism according to claim 10, characterized in that: The stud holder (31, 71) is integral with the spring (57, 72), preferably made of the same material.

12. A speed regulating mechanism according to any one of the preceding claims, characterized in that: The stud holder (31, 71) is arranged on the balance cock (22, 52) around a bearing (28) on the balance staff (24).

13. A watch movement, characterized in that: The timepiece movement comprises a regulating organ (1, 40) according to any one of the preceding claims.

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

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