Device for the autonomous adjustment of the active length of a hairspring

Abstract

The present invention relates to a device (6) for autonomous adjustment of the active length of a balance spring (5), for a balance-spring type oscillator (4, 5), comprising a cock (12) mounted on a plate (13) of a watch movement (2) and in which a balance shaft pivots, the balance spring (5) having an inner end fixed to the balance shaft and an outer end fixed to a stud (8) attached to a stud holder (10), the stud holder (10) being pivotally mounted on the cock (12) concentrically with the balance shaft, and means for modifying the active length of the balance spring (5).

Description

Technical field of the invention

[0001] The invention relates to an autonomous adjustment device for the active length of a spiral, for a balance-spiral type oscillator.

[0002] The invention also relates to a watch movement comprising the autonomous adjustment device for the active length of a balance spring and a balance-spring type oscillator.

[0003] The invention further relates to a timepiece, in particular a watch, comprising the watch movement. Technological background

[0004] In the field of watches equipped with mechanical oscillators of the balance-spring type, there are known mechanisms for manually adjusting the active length of the spring.

[0005] For example, in common manual adjustment mechanisms, the outer end of the balance spring is held in place by a stud attached to a stud holder fixed to a balance cock. A regulator, which rotates relative to the stud holder, is used to adjust the active length of the balance spring, thus allowing adjustment of the balance wheel's frequency. The regulator is a lever, usually with two arms, that pivots centered on the balance staff. One arm of the regulator, for example, carries two pins between which the balance spring is free. A second arm of the regulator can be manually operated to rotate the regulator through a certain angle around the balance staff. This allows the actual position of the counting point to be changed. When the regulator rotates, the active length of the balance spring is shortened or lengthened.However, a drawback of such a manual adjustment system is that gravity influences the frequency of the balance wheel and hairspring oscillations depending on the orientation of the corresponding watch movement. Thus, a watch's rate can vary significantly between its horizontal and vertical positions, for example. Furthermore, when the hairspring moves between the pins due to play between them, the oscillations of the balance wheel and hairspring cause a disturbance in its active length and therefore a slight variation in the frequency of the overall balance wheel and hairspring oscillations.

[0006] To limit the negative effects of gravity, a solution is known, notably from patent document CH 705 605 B1, implementing a device for adjusting the active length of the balance spring. In this device, the regulator incorporates clamping means designed to pinch a terminal portion of the balance spring to define its active length. The outer end of the balance spring is further secured to a fastening system mounted movably relative to the regulator and arranged to cooperate with it. The clamping means, consisting, for example, of a pin-eccentric clamping system in which the terminal portion of the balance spring is pinched, can be loosened or tightened at will by a watchmaker.When the watchmaker loosens the pin-eccentric clamping system, they can move the fixing system using a tool, thus moving the balance spring relative to the fixed regulator and therefore relative to the pin, thereby altering the active length of the balance spring. The watchmaker can then clamp the balance spring against the pin by tightening the clamping system to return the regulating device to its operating position. However, this solution remains a manual adjustment method, which has the drawback of significantly limiting the precision of the adjustment needed to counteract the effects of gravity. Furthermore, this solution is tedious to implement due to the various manual adjustment steps required by the watchmaker.

[0007] Document EP 3 502 788 A1 discloses a device for autonomously adjusting the active length of a spiral. Summary of the invention

[0008] The invention therefore aims to provide a device for adjusting the active length of a spiral, for a balance-spring type oscillator, allowing to counterbalance in a simple, precise and autonomous way the effects of gravity, in particular the perturbations of the isochronism of the balance wheel of the oscillator, and overcoming the aforementioned disadvantages of the prior art.

[0009] To this end, the invention relates to an autonomous adjustment device for the active length of a balance spring, for a balance-spring type oscillator, comprising a cock mounted on a plate of a watch movement and in which a balance shaft pivots, the balance spring having an inner end fixed to the balance shaft and an outer end fixed to a stud attached to a stud holder, the stud holder being pivotally mounted on the cock concentrically to the balance shaft, and means for modifying the active length of the balance spring.

[0010] According to the invention, the means for modifying the active length of the spiral include: a first arm capable of moving between a rest position and a correction position of the device, the first arm having a first free end and a second end cooperating with a first pair of pins fixed on the eyelet holder, the pair of pins being angularly offset with respect to the eyelet; a second arm capable of moving between a rest position and a correction position of the device, the second arm having a first free end and a second end cooperating with a second pair of pins mounted on the eyelet holder, the second pair of pins being angularly offset with respect to the first pair of pins; elastic constraint means configured to exert an elastic restoring action in the rest position on the arms;a spherical weight, mobile in rotation around two axes perpendicular to each other, the weight being arranged to move according to gravity, the movement of the weight causing in rotation a shaft on which a cam is mounted, the rotation of the cam causing a movement of the first arm, and in translation a lever arranged to cooperate with the second arm, to act on the spiral and simultaneously modify the active length of the spiral. ;

[0011] In accordance with other advantageous variants of the invention The spherical weight comprises a solid part and a hollow part, the solid part forming an unbalance allowing the sphere to return to its rest position; the spherical weight comprises a first ring on a great circle of the spherical weight, and a second ring encircling the spherical weight, each ring defining a degree of rotation of the spherical weight; the first ring and the spherical weight form a single unit; the first ring comprises at least one recess arranged to cooperate with a feeler attached to the lever, the lever moving when the feeler passes through the recess, the at least one recess corresponding to a correction position; the cam is a radial cam with an external profile; in the rest position of the device, a flat portion of the cam is in contact with the first arm, and in the correction position of the device, a corner or angle of the cam is in contact with the first arm;the cam is in permanent contact with the free end of the first arm regardless of the position of the weight; the free end of the first arm includes elastically deformable adjustment means, the adjustment means being in the form of a leaf spring, one end of which is fixed to the arm and the other end is free, the free end being arranged to be put under stress and adjust the length of the first arm; the free end of the second arm includes elastically deformable adjustment means, the adjustment means being in the form of a leaf spring, one end of which is fixed to the arm and the other end is free, the free end being arranged to be put under stress and adjust the length of the second arm;The device includes means for adjusting the elastic constraint, the adjustment means being in the form of a screw, the screw passing through the free end and bearing against the arm; the first pair of pins is fixed to the stud holder via a first support, the first arm being arranged so that it slides between the two pins and comes into contact with the outer coil of the balance spring in the correction position; the second pair of pins is fixed to the stud holder via a second support, the second arm being arranged so that it passes between the two pins and comes into contact with the outer coil of the balance spring in the correction position.

[0012] An advantage of the adjustment device according to the invention lies in the fact that it comprises a freely rotating weight that indirectly cooperates with a movable arm arranged to act on the outer coil of the balance spring. Rotation of the weight, freely subjected to gravity, thus causes a displacement of the arm between a rest position and a correction position of the device, and simultaneously acts on the balance spring to modify its active length, allowing it to be adjusted to compensate for perturbations in the balance wheel's isochronism due to gravity. Consequently, the adjustment device according to the invention makes it possible to precisely compensate for the oscillator's rate as a function of its position in space, counterbalancing perturbations in the balance wheel's isochronism due to gravity, and to do so autonomously.

[0013] The invention also relates to a watch movement comprising the setting device described above, and which includes the features mentioned in dependent claim 14.

[0014] The invention also relates to a timepiece comprising the clock movement described above, and which includes the features mentioned in dependent claim 15.

[0015] Other features and advantages of the present invention will become apparent in the following description of a preferred embodiment, presented by way of non-limiting example with reference to the accompanying drawings. Brief description of the figures

[0016] The purposes, advantages, and characteristics of the device for adjusting the active length of a balance spring, as well as of the watch movement and the timepiece comprising it, will become clearer from the following description based on at least one non-limiting embodiment illustrated by the drawings in which: there figure 1 is a perspective view of a watch movement comprising a device for adjusting the active length of a balance spring according to the invention; the figure 2 an exploded perspective view of the adjustment device figure 1 ; there figure 3 is a top view of the adjustment device of the figure 1 . Detailed description of the invention

[0017] The following description refers to a watch movement equipped with a device for adjusting the active length of a balance spring, for a balance-spring type oscillator. The usual components of a watch movement, which are well known to a person skilled in this technical field, are described only in simplified form or not at all. A person skilled in the art will be able to adapt these various components and make them work together for the operation of the watch movement. In particular, everything concerning the escapement mechanism of the watch movement will not be described hereafter, although such an escapement mechanism could advantageously cooperate with the adjusting device according to the invention.

[0018] There figure 1 represents a part of a timepiece 1, which includes a watch movement 2. In the particular embodiment example of the figure 1The timepiece 1 is a watch. The watch movement 2 comprises an oscillator equipped with a balance wheel 4 and a balance spring 5, and a device 6 for independently adjusting the active length of the balance spring 5. Conventionally, the balance spring 5 is attached to a balance staff by its inner end (not visible). The balance staff has one end mounted on a pivot in a balance bridge (the latter not shown in the figures for clarity). The outer end of the balance spring 5 is conventionally attached to a stud 8 fixed to a stud holder 10, the stud holder 10 being secured to a balance cock 12 by slight clamping. More precisely, the stud holder 10 is pivotally mounted on the balance cock 12 concentrically with the balance wheel 4, as illustrated in the figure. figure 2 The balance shaft is pivotally mounted in the balance cock 12.

[0019] The means 6 for modifying the active length of the spiral 5 are suitable for modifying the active length of the spiral 5 by acting on the length of the outer coil of the spiral 5.

[0020] In a particular example of implementation illustrated on the figure 1The means for modifying the active length of the balance spring 5 comprise a first arm 60 capable of moving between a rest position and a correction position of the device. The first arm has a first free end 600 and a second end 601 cooperating with a first pair of pins 19 forming a guide fork for the first arm 60. The first pair of pins 19 is mounted on the stud holder 10 and offset angularly relative to the stud 8 via a first support 8'. The position of the first support 8' can be modified radially relative to the stud holder 10. Thus, the second end 601 of the arm 60 can slide between the two pins 19 and comes into contact with the outer coil of the balance spring 5 in the correction position to modify the active length of the balance spring.

[0021] The adjustment device also includes a second arm 61 capable of moving between a rest position and a correction position of the device. The second arm 61 has a first free end 610 and a second end cooperating with a second pair of pins 19' forming a guide fork for the second arm 61. The second pair of pins 19' is mounted on the stud holder 10 and offset angularly relative to the stud and the first pair of pins 19 via a second support 8". The position of the second support 8" can be modified radially relative to the stud holder 10. Thus, the second end 611 of the second arm 61 can slide between the two pins 19' and comes into contact with the outer coil of the balance spring in the correction position to modify the active length of the balance spring.

[0022] The means 6 for modifying the active length of the balance spring also include a spherical weight 40 that rotates about two perpendicular axes A and B. The spherical weight 40 is arranged to rotate about at least one of the axes A and B as a function of gravity, the movement of the weight 40 causing a shaft 30 on which a cam 31 is mounted to rotate and / or a lever 49 to move. Thus, the rotation of the cam 31 causes the arm 60 to move in order to act on the balance spring and simultaneously modify the active length of the balance spring 5, and the same is true for the lever 49, which is arranged to cooperate with the second arm 61 and move the latter to act on the balance spring and simultaneously modify the active length of the balance spring 5.

[0023] As can be seen in the figure 2The weight 40 is in the form of a spherical body rotating about the axis A and comprising a solid portion 400 and a perforated portion 401 with perforated elements 43, each portion forming half of the spherical weight 40. Advantageously, the solid portion 400 forms an unbalance and allows the weight 40 to return to its rest position.

[0024] As can be seen in the figure 2 The spherical weight comprises a first ring 41 on a great circle of the spherical weight, and a second ring 46 rotating about the axis B and encircling the spherical weight, the weight 40 being arranged to rotate in the second ring 46. Thus, each ring rotates about an axis and defines a degree of rotation of the spherical weight 40.

[0025] The first ring 41 and the spherical weight 40 form a single unit and the first ring includes at least one hollow 42 arranged to cooperate with a feeler 48 attached to the lever 49, the lever moving when the feeler 49 passes through the hollow 48. The hollow 42 corresponds to a correction position, and it can obviously have several hollows on the surface of the first ring 41 so as to define a plurality of correction positions.

[0026] The sphere 40 and the second ring 46 are fixed to the plate 13 via a semi-circular frame 47, each end of the frame 47 having an opening to allow respectively the passage of the lever 49 acting on the second arm 61 and of a drive shaft 45 driving a first pinion 21 engaging a second pinion 22 fixed to the shaft 30 on which is mounted the cam 31 which acts on the first arm 60.

[0027] The adjustment device includes elastic constraint means configured to exert an elastic return action on the arms 60, 61. The elastic constraint means are in the form of a rod 62 integral with the arm 60 and a spring blade 63 integral with the eyelet holder 10, the spring blade 61 exerting a return force on the rod 62 and exerting an elastic return action on the arm 60. Elastic constraint means are also associated with the second arm 61, and include a rod 64 integral with the second arm 61 and a spring blade 65 integral with the eyelet holder 10, the spring blade 65 exerting a return force on the rod 64 and exerting an elastic return action on the second arm 61.

[0028] The adjustment device 6 also includes means for adjusting the arms 60, 61, and the free ends 600, 610 of the first and second arms 60, 61, comprising elastically deformable adjustment means for lengthening or shortening the arms. The adjustment means are in the form of a leaf spring, one end of which is fixed to the arm and the other end is free. The free end is arranged to be subjected to tension and to adjust the length of the arms 60, 61, the leaf spring forming a gap between itself and the free end of each arm. Such adjustment is necessary depending on the position of the spiral and the correction required for the spiral.

[0029] The means for modifying the active length of the spiral 5 include two pins 19 fixed to the second pin 8', the second end 601 of the arm 60 being arranged so that it slides between the two pins 19 and comes into contact with the outer coil of the spiral 5 in the correction position and thus modifies the active length of the spiral.

[0030] The means for modifying the active length of the spiral 5 include two further pins 19' fixed to the third pin 8", the second end 611 of the second arm 61 being arranged so that it passes between the two pins 19' and comes into contact with the outer coil of the spiral 5 in the correction position.

[0031] Furthermore, each arm 60, 61 includes means for adjusting the elastic stress. These adjustment means take the form of a screw, the screw passing through the free end of the spring blade and bearing against the arm. Thus, when the screw is tightened, the free end of the blade moves away and the distance between the blade and the free end 600, 610 of arms 60, 61 increases, thereby increasing the length of arms 60, 61. Conversely, when the screw is loosened, the free end of the blade moves towards the free end 600, 610 and the distance between the blade and the free end 600, 610 of arms 60, 61 decreases, thereby increasing the length of arms 60, 61.

[0032] According to a preferred embodiment, the weight 40 is free to move in rotation around the two axes A and B. Thus, movement of the weight 40 causes a rotation of the first ring 41 and / or the second ring 46, and respectively a rotation of the drive shaft 45 which drives the first pinion 21 meshing with the second pinion 22 fixed to the shaft 30 on which the cam 31 is mounted, and / or a translation of the lever 49.

[0033] Thus, a movement of the weight 40 results in a movement of at least one of the arms 60, 61, acting simultaneously on the means for modifying the active length of the balance spring 5. The movement of the arms, under the effect of the displacement of the weight 40 subjected to gravity, occurs between a rest position of the device and a correction position of the device. Each arm allows a distinct correction depending on the position of the watch, and thus continuously adjusts the active length of the balance spring to compensate for the perturbations of the balance wheel's isochronism due to gravity.

[0034] In the preferred embodiment in which the device 6 includes a cam 31 for driving the first arm 60, the cam is fixed to the shaft 30 and is in contact with the free end 600 of the first arm 60.

[0035] Preferably, cam 31 is a radial cam with an external profile. Although a radial cam with a substantially circular external profile is shown on the figures 1 to 3 In practice, the shape envisaged for the external profile of the cam will depend on the type of spiral 5 used and the correction to be applied. For example, a radial cam with a triangular, oblong, or even ovoid external profile can also be used within the framework of the present invention. Preferably, and as shown in the figure 2 In the rest position of the adjustment device 6, a flat portion of the cam 31 is in contact with the first arm 60, while in the correction position of the device 6, a corner or angle of the cam 31 is in contact with the arm 60. Preferably, as can be seen in the figures, the cam 31 is in contact with the first arm 60 regardless of the position of the weight 40.

[0036] It is thus conceived that, depending on the position of the watch movement 2 in space, the spherical weight 40, freely subjected to gravity, can pivot and cause a displacement of the arms 60, 61. In doing so, the displacement of the weight makes it possible to act simultaneously on the means of modifying the active length of the balance spring 5, allowing the active length of the balance spring to be continuously adjusted in order to compensate for the disturbances of the isochronism of the balance wheel due to gravity.

[0037] Once the weight has stabilized following its change of position, the device will return by itself to the rest position thanks to the action of the imbalance formed by the solid portion 400 of the weight 40.

[0038] The invention also relates to a watch movement 2 comprising a balance-spring type oscillator 4, 5 and an autonomous adjustment device 6 for the active length of the spring 5 as described above.

[0039] The invention also relates to a timepiece 1 comprising a watch movement 2 equipped with a device 6 for autonomously adjusting the active length of the balance spring 5 as described above.

Claims

1. Device (6) for autonomously adjusting the active length of a balance spring (5), for an oscillator (4, 5) of the sprung balance type, comprising a cock (12) designed to be mounted on a plate (13) of a horological movement (2) and in which a balance staff can pivot, the balance spring (5) including an inner end designed for integrity with the balance staff and an outer end integral with a stud (8) fastened to a stud-holder (10), the stud-holder (10) being pivotally mounted on the cock (12) concentrically with the balance staff, and means for modifying the active length of the balance spring (5); in which the means for modifying the active length of the balance spring comprise: a first arm (60) able to move between a rest position and a correction position of the device, the first arm (60) having a first free end (600) and a second end (601) cooperating with a first pair of pins (19) mounted on the stud-holder (10), the first pair of pins (19) being angularly offset relative to the stud (8);characterised in that it includes : - a second arm (61) capable of moving between a rest position and a correction position of the device, the second arm having a first free end (610) and a second end (611) cooperating with a second pair of pins (19') mounted on the stud-holder (10), the second pair of pins (19') being angularly offset relative to the first pair of pins (19) and to the stud (8); - resilient stressing means (62, 63, 64, 65) configured to exert a resilient restoring action on the arms (60, 61); - a spherical inertia block (40), rotatable about two mutually perpendicular axes, the inertia block being arranged to move as a function of gravity, the movement of the inertia block (40) rotating a shaft (30) on which a cam (31) is mounted, the rotation of the cam (31) causing the first arm (60) to move, and translating a lever (49) arranged to cooperate with the second arm (61), and act on the balance spring and simultaneously modify the active length of the balance spring (5).

2. Device (6) for autonomously adjusting the active length of a balance spring (5) according to claim 1, characterised in that the spherical inertia block (40) comprises a solid part (400) and a recessed part (401), the solid part (400) forming an unbalance allowing the sphere to return to its rest position.

3. Device (6) for autonomously adjusting the active length of a balance spring (5) according to claim 2, characterised in that the spherical inertia block comprises a first ring (41) on a large circle of the spherical inertia block, and a second ring (46) encircling the spherical inertia block, each ring defining a degree of rotation of the spherical inertia block (40).

4. Device (6) for autonomously adjusting the active length of a balance spring (5) according to claim 3, characterised in that the first ring (41) and the spherical inertia block (40) form a one-piece element.

5. Device (6) for autonomously adjusting the active length of a balance spring (5) according to claim 3 or 4, characterised in that the first ring comprises at least one recess (42) arranged to cooperate with a feeler (48) integral with the lever (49), the lever moving when the feeler (49) passes through the recess (48), the at least one recess (42) corresponding to a correction position.

6. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of the preceding claims, characterised in that the cam (31) is a radial cam with an external profile.

7. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of claims 1 to 6, characterised in that, when the device (6) is in the rest position, a flat portion of the cam (31) is in contact with the first arm (60), and when the device (6) is in the correction position, a corner or angle of the cam (31) is in contact with the first arm (60).

8. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of claims 1 to 7, characterised in that the cam (31) is in permanent contact with the free end (60) of the first arm (60) whatever the position of the inertia block (40).

9. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of the preceding claims, characterised in that the free end (600) of the first arm (60) comprises resiliently deformable adjustment means, the adjustment means being in the form of a strip-spring, a first end of which is integral with the arm and another end of which is free, the free end being arranged to be stressed and to adjust the length of the first arm (60).

10. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of the preceding claims, characterised in that the free end (610) of the second arm (61) comprises resiliently deformable adjustment means, the adjustment means being in the form of a strip-spring, a first end of which is integral with the arm and another end of which is free, the free end being arranged to be stressed and to adjust the length of the second arm (61).

11. Device (6) for autonomously adjusting the active length of a balance spring (5) according to claim 9 or 10, characterised in that it comprises means for adjusting the resilient stress, the adjustment means being in the form of a screw, the screw passing through the free end and bearing against the arm.

12. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of the preceding claims, characterised in that the first pair of pins (19) is fastened to the stud-holder (10) via a first support (8'), the first arm (60) being arranged so that it slides between the two pins (19) and comes into contact with the outer coil of the balance spring in the correction position.

13. Device (6) for autonomously adjusting the active length of a balance spring (5) according to one of the preceding claims, characterised in that the second pair of pins (19') is fastened to the stud-holder (10) via a second support (8"), the arm (61) being arranged so that it passes between the two pins (19) and comes into contact with the outer coil of the balance spring in the correction position.

14. Horological movement (2) including an oscillator (4, 5) of the sprung balance type and a device (6) for autonomously adjusting the active length of the balance spring (5), characterised in that the autonomous adjustment device (6) is in accordance with any one of claims 1 to 13.

15. Timepiece (1) including a horological movement (2), characterised in that the horological movement (2) is in accordance with claim 14.

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