Patent Application
20250036081
This application claims priority to European Patent Application No. 23187214.4 filed Jul. 24, 2023, the entire contents of which are incorporated herein by reference.
The invention relates to the field of watchmaking, and more particularly to the field of mechanical watchmaking, where the regulation of the driving energy is provided by a regulating member.
More specifically, the invention relates to a regulating member provided with an actuation system, a horological movement comprising such a regulating member, and a timepiece comprising such a horological movement.
In most mechanical watches, the energy required to rotate the hands (for example the minute and hour hands) is stored in a barrel and then delivered by a sprung balance system, which comprises a flywheel called a balance, combined with a spring in the form of a spirally wound ribbon called a balance spring.
An inside end of the balance spring is attached to a staff that rotates as one with the balance; an outside end of the balance spring is attached to a stud mounted on a stud-holder that is itself rigidly connected to a stationary cock.
The rotation of the balance is maintained—and its oscillations counted—by an escapement mechanism comprising a pallet-lever animated by a low-amplitude oscillating motion, provided with two pallets which engage the teeth of an escape wheel. When the escape wheel is engaged in this way, it is caused to rotate in steps, the speed of which rotation is determined by the frequency of oscillation of the pallet-lever, which is itself set to the frequency of oscillation of the sprung balance.
In a conventional escapement mechanism, the oscillation frequency is around 4 Hz, or approximately 28,800 vibrations per hour (V/h). One of the objectives of good watchmakers is to ensure the isochronism and regularity of the oscillations (or constancy of rate) of the balance.
The rate of the balance can be regulated in a known manner by adjusting the active length of the balance spring, defined as the curvilinear length between its inside end and a counting point, located in the vicinity of the outside end of the balance spring and typically defined by a pair of bankings carried by a key mounted on an index system.
In operation, this index system is not able to 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 acting like a cam on the index system using a screwdriver.
The assembly comprising the cock, the index system, the key, the stud-holder, the stud, the staff, the spring and the balance is commonly referred to as the “regulating member”. Examples of regulating members are given in the European patent EP 2 876 504 field by the watch manufacturer ETA.
There are index systems which have a stud-holder to which one end of the balance spring is attached, and where the index system key leaves play to allow the balance spring to move between the two bankings. However, the chronometric properties, in particular the anisochronism as a function of amplitude, are very sensitive to the play of the balance spring at the index key, and this play is difficult to control precisely.
In some devices, the bankings can be adjusted to clamp the balance spring in order to eliminate play, particularly when the balance spring is in operation. In this case, first the rate is regulated by moving the index key, then clamping the balance spring to the key. However, clamping the balance spring to the index key risks stressing it and creating chronometric errors, in particular due to the off-centring of the windings. Moreover, removing the play also changes the rate, and once the balance spring has been clamped, you can no longer move the index key along the balance spring to finish fine-tuning the rate.
Other balance springs have an integrated regulating device. In these balance springs, the rate is not regulated by altering the effective length of the balance spring, but by applying a force or torque to a flexible element arranged in series with the balance spring. In this way, the stiffness of the flexible element and consequently of the balance spring as a whole, i.e. of the ribbon and of the flexible element, can be modified. Adjusting the stiffness of the balance spring allows the rate of the regulating member to be regulated. Such a balance spring provided with a flexible element is described, for example, in patent applications EP4009115 and CH0700385/2021.
In these cases, the usual systems cannot be used, as they are not compatible with the balance spring regulating device. Moreover, as the rate has to be regulated to a very fine degree, it is essential that there is no play between the balance spring and the areas where it interacts with the index mechanism. More specifically, if this were not the case, there would be a risk of the rate being altered in the event of an impact, if the balance spring does not reposition itself in exactly the same way after the impact.
To use such a balance spring, an index system has been described in patent applications EP22177059.7 and CH000678/2022. The index system comprises a stud-holder in two parts that can move relative to each other, each part being provided with a stud on which the flexible element is mounted on the one hand, and the prestressing means acting on the flexible element on the other. Thus, by moving the two parts relative to each other, the force or torque applied to the flexible element is modified, in order to adjust the stiffness of the balance spring assembly.
However, the index system is complex to implement, as the movable parts of the stud-holder each perform a rotary motion above the balance spring.
Furthermore, with this index system, the regulating member takes up a significant amount of space in the movement, which increases its thickness in particular. However, only certain movements are capable of incorporating such a system. It cannot be fitted in smaller and, above all, thinner movements.
Other actuation systems are possible, for example systems with a linear or even rectilinear displacement actuator. However, this type of actuator must be easy to actuate. Yet, no simple actuation system that is compatible with a linear displacement actuator exists.
The aim of the present invention is to overcome some or all of the above-mentioned drawbacks by providing an actuation system compatible with this type of linear displacement actuator.
To this end, the invention relates to a regulating member for a horological movement, comprising an inertial mass, for example a balance, a balance spring comprising a wound ribbon, and means for adjusting the stiffness of the balance spring, the regulating member comprising a system for actuating the adjustment means, the actuation system comprising an actuator comprising a movable part mechanically connected to the adjustment means, and means for regulating the actuator.
The invention is characterised in that the regulating means comprise a pivoting control lever, the control lever comprising a pivot arm, and a support arm cooperating with the movable part of the actuator in order to displace it mechanically.
The invention thus provides a simplified actuation system, because it allows the use of an actuator undergoing linear displacement, preferably rectilinear displacement, rather than rotary displacement.
According to a particular embodiment of the invention, the control lever comprises a hub configured to rotate about a body mounted on a cock or plate of the horological movement, the pivot arm and the support arm being connected to the hub.
According to a particular embodiment of the invention, the control lever is configured to pivot in a plane substantially perpendicular to the plane of the actuator.
According to a particular embodiment of the invention, the regulating means comprise a control screw mechanically connected to the pivot arm to control the pivoting of the control lever.
According to a particular embodiment of the invention, the control screw is arranged in the plane of the control lever.
According to a particular embodiment of the invention, the movable part of the actuator comprises a bulge serving as a support for moving the movable part, the support arm being in contact with the bulge.
According to a particular embodiment of the invention, the adjustment means are provided with a flexible element arranged in series with the wound ribbon, the adjustment means comprising prestressing means for applying a variable force or torque to the flexible element in order to adjust the rate of the regulating member, the actuator being mechanically connected to the prestressing means.
According to a particular embodiment of the invention, the actuator is configured to perform at least in part a substantially linear, preferably rectilinear, displacement, in order to actuate the prestressing means.
According to a particular embodiment of the invention, the actuator is displaced substantially radially with respect to the balance spring.
According to a particular embodiment of the invention, the actuator is off-centred and mounted at a distance from the centre of the regulating member.
According to a particular embodiment of the invention, the regulating element comprises a balance cock, on which the actuator is mounted, the actuator being substantially perpendicular to the balance cock.
According to a particular embodiment of the invention, the actuator further comprises a part that is stationary relative to the balance cock and a spring part connecting the movable part to the stationary part.
The invention further relates to a horological movement comprising such a regulating member.
The invention further relates to a timepiece including such a horological movement.
The aims, advantages and features of the present invention will become apparent from the detailed description of several embodiments given solely by way of non-limiting examples, with reference to the accompanying drawings in which:
The regulating member 1 comprises an inertial mass, in this case an annular balance 23, a balance spring 25 as an elastic return element for the inertial mass configured to cause it to oscillate, a balance staff 24, and a balance cock 22. The elements are stacked from bottom to top in the following order: the balance 23, the balance spring 25 and the balance cock 22.
The balance staff 24 passes through the centre of the balance, the balance spring 25 and the balance cock 22. The balance staff 24 is held by two shock-absorbing bearings 28 arranged at both ends of the balance staff 24. A first bearing is arranged below the balance cock 22, and the second bearing 28 is arranged therein. The balance cock 22 has a through-hole inside which the second bearing 28 is held.
Shown in
The balance spring 25 further includes means for adjusting its stiffness. For example, the adjustment means can in particular be actuated by a user when the regulating member is mounted in the horological movement.
The adjustment means comprise a flexible element 5 arranged in series with the ribbon 2, i.e. following on from the ribbon, preferably as an extension thereof, the flexible element 5 connecting an outside end 4 of said ribbon 2 to a rigid support 17. The flexible element 5 is integral with the outside end 4 of the ribbon 2. The flexible element 5 is a different element from the ribbon 2.
The flexible element 5 adds additional stiffness to that of the ribbon 2. The flexible element 5 is preferably stiffer than the ribbon 2. In this case, the flexible element 5 is arranged as an extension of the ribbon 2. Preferably, the adjustment means and the ribbon 2 are in one piece, or even made of the same material, for example silicon.
The flexible element 5 of the balance spring 25 comprises a first flexible blade 19 and a movable semi-rigid part 18, which extends from the outside end of the ribbon 2, and is connected to the first flexible blade 19, preferably on the same side of the rigid part 18. The first flexible blade 19 is also connected to the rigid support 17.
The rigid support 17 is L-shaped, with a first leg 46 of the L serving as a connection to the first flexible blade 19, and the second leg 47 of the L facing away from the first flexible blade 19 so that it can be assembled to the horological movement.
The means for adjusting the balance spring 25 further include 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. The torque or force is continuously adjustable thanks to the prestressing means 6. In other words, the torque or force is not restricted to isolated values. The stiffness of the flexible element 5 can thus be adjusted with great precision.
The prestressing means 6 comprise a secondary flexible blade 21, arranged on an opposite side of the rigid part 18 in the extension of the first flexible blade 19.
The other end of the secondary flexible blade 21 is connected to a curved lever 14 which runs around the ribbon 2. The lever 14 is connected, in addition to the secondary flexible blade 21, to a semi-rigid structure 27 attached to the rigid support 17. The semi-rigid structure 27 deforms in part when the lever 14 is actuated by the force or torque.
The force or torque is exerted on the free end 15 of the lever 14. In this way, the lever 14 of the prestressing means 6 transmits the force or torque to the flexible element 5 via the secondary flexible blade 21 and the semi-rigid structure 27, so as to modify the stiffness of the balance spring 25.
In order to be able to apply the variable force or torque to the balance spring 25, the regulating member comprises a specific actuation system 20 in accordance with the invention.
In the embodiment shown in
The stud 34 cooperates with the second leg 47 of the rigid support 17. In this way, the prestressing means 6 and the flexible element 5 are supported by the stud-holder 31 from which they are suspended.
Moreover, the stud 34 is rigidly attached to the rigid support 17. In other words, the stud 34 is integral with the rigid support 17. The stud 34 and the balance spring 25 are assembled, for example, by bonding, brazing, welding, by deformation of metallic glass, or by mechanical fastening.
The stud 34 can move relative to the balance cock. To this end, the stud-holder 31 can rotate about the second bearing 28 relative to the balance cock 22. The stud-holder 34 can, for example, be displaced over an angular range of 20° or even 10°.
By displacing the pin 34 relative to the balance cock 22, the beat of the regulating member 1 can be regulated.
The actuation system 20 further comprises an actuator 30 configured to actuate the lever 14. The actuator 30 is mechanically connected to the prestressing means 6, the actuator 30 being configured to perform at least in part a substantially linear, preferably rectilinear, displacement, in order to actuate the prestressing means 6.
In other words, at least part of the actuator 30 moves substantially along a straight line, unlike, for example, the stud-holder 31 which undergoes rotation by turning about an axis. In this way, at least part of the actuator 30 moves towards or away from the balance spring 25 in a direction oriented substantially towards the balance spring.
Preferably, the direction of displacement of the actuator 30 is substantially radial with respect to the balance 23 and the balance spring 25. In this way, the straight line along which the actuator 30 moves is directed towards the centre of the balance 23 and the balance spring 25. This also makes the rate setting independent of the beat setting.
The actuator 30 is off-centred with respect to the regulating member, i.e. it is mounted at a distance from the centre of the regulating member 1, and is connected only to the lever 14 of the adjustment means. The actuator 30 is therefore not mounted directly on the regulating member 1, like a stud-holder on a bearing 28 of the regulating member 1, for example.
In this embodiment, the actuator 30 is mounted on the balance cock 22. Preferably, the actuator 30 is mounted on the plate substantially perpendicular to the balance cock 22. More specifically, it is assembled on an edge of the balance cock 22.
In
To actuate the lever 14, the actuator 30 comprises a hook 39 engaged with the lever 14, the hook 39 being mounted on the movable part 37. The hook 39 at least partially surrounds the lever 14, but may also be closed around the lever 14.
A radial displacement of the movable part 37 of the actuator 30 pulls or pushes the lever 14 radially with respect to the balance spring 25. This changes the stiffness of the flexible element 5, as the displacement of the lever exerts a greater or lesser force or torque on the flexible element 5, so that the stiffness of the flexible element 5 varies, and consequently the stiffness of the balance spring 25 as a whole also varies. The actuation system 20 thus allows the rate of the regulating member 1 to be regulated.
The stationary part 33 here has a substantially square shape, and is provided with at least one attachment notch 41, preferably two attachment notches 41, 42, each for receiving a pad 43, 44 extending from the balance cock 22. The attachment notches 41, 42 are arranged, for example, on two diagonally opposite sides of the stationary part 33.
Each notch 41, 42 is provided with a flexible tongue 48, 49 arranged in the notch 41, 42. The first notch 41 is open at the side so that it can slide laterally around the first pad 43. The second notch 42 is closed and can receive the second pad 44 by insertion into the second notch 42. The flexible tongues 48, 49 deform when a pad 43, 44 enters the notch 41, 42, and act as a means of support to retain the pad 43, 44 in the notch 41, 42. Moreover, the flexible tongues 48, 49 make it possible to improve positioning accuracy by overcoming the play in the positioning of the pads 43, 44 in the notches 41, 42, preferably in the same direction.
As shown in the figures, the actuator 30 is mounted on the balance cock 22, so as to be substantially perpendicular to the plate and to the balance cock 22. It is therefore mounted on the edge of the balance cock 22.
The spring part 35 is arranged below the stationary part 33, so that it extends below the level of the balance cock 22.
In this case, the spring part 35 comprises a plurality of translation stages 51, 52, 53, 54 with flexible blades arranged in series, one after the other. They are defined as being in series because the displacements of each translation stage are at least partly cumulative.
Each translation stage 51, 52, 53, 54 comprises a pair of substantially parallel flexible blades 61, 62, 63, 64 and a rigid section 56, 57, 58, 59 on which the pair of flexible blades 61, 62, 63, 64 is mounted.
The first translation stage 51 is arranged under the stationary part 33 and has a first rigid section 56 which is lengthened in order to be associated with a second translation stage 52 arranged head-to-tail with the first translation stage 51. In this way, the second pair of flexible blades 52 is substantially parallel to the first pair of flexible blades 51. The second rigid section 57 is substantially parallel to the first rigid section 56, but is offset by half the length of the first rigid section 56.
The second rigid section 57 is also lengthened to associate a third translation stage 53 arranged head-to-tail with the second translation stage 52, and therefore substantially parallel to the first translation stage 51. The third pair of flexible blades 63 is substantially parallel to the first 61 and the second pair of flexible blades 62.
The actuator 30 comprises a fourth translation stage 54 arranged on the other side of the first translation stage 5 from the second 52 and the third translation stage 53. The fourth translation stage 54 is arranged head-to-tail with the third translation stage 53.
In this way, the fourth pair of flexible blades 64 is substantially parallel to the other pairs of flexible blades, and the fourth section 59 is arranged in substantially the same direction as the second section 57.
The third 53 and the fourth translation stage 54 are connected by an arm 55 extending from the third section 58, and passing below the first rigid section 56 of the first translation stage 51.
This arrangement of translation stages 51, 52, 53 and 54 enables the movable part 37 to be displaced in a substantially linear, preferably rectilinear, manner, while maintaining a compact actuator 30.
Preferably, the actuator 30 comprises an even number of translation stages, as two translation stages arranged head to tail enable the vertical deviation of the hook 39 generated by each to be mutually compensated for. In this way, the hook 39 remains at substantially the same height while moving.
The movable part 37 extends from the fourth section 59. The movable part 37 is preferably rigid. In this case, the movable part 37 has the shape of an elbow formed by a first segment 66 arranged perpendicular to the fourth section 59 and a second segment 67 forming a right angle with the first segment 66.
The hook 39 of the actuator 30 is located at the end of the second segment 67. At the free end of the first segment 66, a bulge 68 acts as a support for moving the movable part 37.
By pressing more or less hard on the bulge 68, the movable part 37 moves more or less closer to the stationary part 33, thanks to the deformation of the translation stages 51, 52, 53, 54 of the spring part 35.
In this way, the hook 39 pulls more or less hard on the lever 14 to actuate the means for adjusting the stiffness of the flexible element 5.
The direction of displacement of the movable part 39 of the actuator 30 and of the lever 14 is substantially orthogonal to the direction of the lever 14.
Moreover, the lever 14 is preferably movable in the hook 39, so that it can move first when the lever 14 performs an angular displacement. To this end, lever 14 comprises a free end 15 cooperating with the hook 39.
For example, in order to be able to adjust the beat of the regulating member 1, the stud-holder 31 must be able to rotate. Consequently, the balance spring 25 rotates with the stud-holder 31, and the free end 15 of the lever 14 slides in the hook 39.
Thanks to such an actuation system 20, the beat can be regulated without having to modify the position of the actuator 30, in particular with respect to the plate of the movement. The mechanical link between the actuator 30 and the lever 14 is maintained, regardless of the position of the lever 14 relative to the actuator 30.
This actuation system 20 thus enables the rate and the beat to be regulated independently of each other, while keeping a constant predetermined position of the actuator in the movement, for example in relation to the plate and the balance cock 22.
The actuation system 20 further comprises regulating means cooperating with the actuator 30 so as to be able to displace the movable part 37 of the actuator 30.
According to the invention, as shown in
The control lever 45 has a pivot arm 69 and a support arm 71 connected to a hub 72 of the pivoting control lever 45.
The support arm 71 cooperates with the movable part 37 of the actuator 30 to displace it mechanically by contact. The support arm 71 pushes the bulge 68 of the movable part 37 to a greater or lesser extent to move it. The hook 39 thus pulls the lever 14 of the balance spring 25 to a greater or lesser extent. The control lever 45 is configured to pivot in a plane substantially perpendicular to the plane of the actuator 30.
The control lever 45 is configured to be mounted on the plate of the movement via the hub 72, which can rotate about a body, in this case a screw body 73, the screw 73 being mounted on the plate.
Thus, by rotating the control lever 45 about the screw body 73, the movable part 37 moves towards or away from the stationary part 33 by deforming the spring part 35 of the actuator 30 to a greater or lesser extent in order to modify the position of the lever 14.
The regulating means further include a control screw 70 mechanically connected to the pivot arm 69, in order to control the pivoting of the control lever 45. The axis of the control screw 70 is arranged in the plane of the control lever 45 in the direction of the pivot arm 69.
The control screw 70 is, for example, arranged through a vertical wall (not shown in the figures), belonging to the plate or mounted on the plate by a cock.
Thus, by screwing or unscrewing the control screw 70, the control lever 45 and the actuator 30 are actuated in order to move the hook 39 and therefore the lever 14 of the prestressing means 6.
The return force of the spring part 35 of the actuator 30 pushes the control lever 45 against the control screw 70. In this way, the pivot arm 69 of the control lever 45 is held against the control screw 70.
In
In
In the second position, the control screw 70 pushes the pivot arm 69 of the control lever 45, so that the support arm 71 in contact with the bulge 68, in turn pushes the movable part 37 of the actuator 30 towards the stationary part 33 by deformation of the spring part 35. In this way, the hook 39 pulls on the lever 14, which performs a centrifugal displacement.
In the deformed configuration of the spring part 35, the flexible blades of the first translation stage 51 and of the third translation stage 53 deform in the same first direction, whereas the flexible blades of the second translation stage 52 and of the fourth translation stage 54 deform in the same second direction, the second direction being opposite to the first direction.
Such a control screw 70 could be accessible from outside a case of the timepiece.
The control screw 70 could be housed through a wall of the case so that it can be screwed in or out using a tool from outside the case, the screw head being at least partly on the outside of the wall of the case.
A spring 74 is arranged around the screw body 73 to press the actuator 30 against the balance cock 22, so that it does not become detached.
The spring 74 clamps the screw body 73. The spring 74 is U-shaped and surrounds the screw body 73. One leg of the U extends in this case from the stationary part 33 of the actuator 30 to which it is attached.
It goes without saying that the invention is not limited to the embodiments of regulating members described with reference to the figures and alternatives can be considered without leaving the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 23187214.4 | Jul 2023 | EP | regional |
