Timepiece regulating organ with a hairspring and an aging compensation device

Abstract

This invention relates to a regulating mechanism (1) for a watch movement, comprising an oscillating mass, such as a balance wheel, and a hairspring comprising a flexible strip (2) wound in multiple turns, the strip (2) having a preset stiffness to enable the oscillating mass to rotate and oscillate, the strip (2) comprising an outer end (9), characterized in that the regulating mechanism (1) includes an elastic device for compensating for drift in the running rate, the elastic device being configured to adapt its own stiffness according to the aging of the regulating mechanism; the elastic device includes an elastic element (5) and a prestressing mechanism (6), the elastic element (5) connecting the outer end (9) to a first fixed support (7) fixed relative to the watch movement, the prestressing mechanism (6) for applying a variable force or torque to the elastic element (5), wherein the force or torque decreases over time. The invention also relates to a watch movement incorporating such a regulating mechanism (1).

Description

Technical Field

[0001] This invention relates to the field of clocks and watches, and more specifically to the field of mechanical clocks and watches, wherein the power energy is regulated by a speed regulating mechanism.

[0002] More specifically, the present invention relates to a speed regulating mechanism having a rated rift compensation device, particularly applicable to the field of watchmaking, a watch movement including such a speed regulating mechanism, and a watch including such a watch movement. Background Technology

[0003] In most mechanical watches, the energy required to move the hands (e.g., the minute and hour hands) is stored in the mainspring barrel and then distributed through the balance spring system, which includes a flywheel called the balance wheel and a spring that works in conjunction with the balance wheel. The spring is in the form of a spiral strip called the hairspring.

[0004] The inner end of the hairspring is attached to the balance shaft, which rotates with the balance wheel; the outer end of the hairspring is attached to the hairspring stud, which is mounted on the stud retainer, which itself is attached to the fixed clamp (also known as the balance clamp).

[0005] The rotation of the balance wheel is maintained by the escapement mechanism, which also counts the number of oscillations. The escapement mechanism includes an escape fork driven by small-amplitude oscillations, with two pallets for engaging with the teeth of the escape wheel. In the engaged state, the escape wheel is forced to rotate in steps, the speed of which is determined by the oscillation frequency of the escape fork, which is itself set to match the oscillation frequency of the balance wheel.

[0006] In a traditional escapement mechanism, the oscillation frequency is approximately 4 Hz, or about 28,800 vibrations per hour (A / h). A skilled watchmaker must ensure that the balance wheel's oscillation is isochronous and stable (meaning that the timekeeping rate remains constant).

[0007] The industry standard practice is to calibrate the balance wheel's speed by adjusting the effective length of the hairspring. The effective length of the hairspring refers to the curve length between the inner end of the hairspring and a measuring point near the outer end of the hairspring, which is typically defined by a pair of limit stops carried by a collet mounted on the regulator assembly.

[0008] During operation, the regulator assembly is fixed in rotation relative to the hairspring axis. However, its angular position can be finely adjusted manually, for example, by turning the regulator assembly with a screwdriver, or by adjusting the eccentric mechanism of the regulator assembly via a cam.

[0009] An assembly comprising a bridge, regulator assembly, chuck, balance spring stud retainer, balance spring stud, balance shaft, balance spring, and balance wheel is commonly referred to in the industry as a "regulating mechanism." European patent EP 2876504, granted to watchmaker ETA, provides an example of a regulating mechanism.

[0010] Some existing regulator assemblies include an outer stud retainer for the hairspring, with one end of the hairspring fixed to this retainer. The regulator assemblies have a certain amount of clearance in the clamps to allow the hairspring to move between two limit stops. However, the timekeeping performance of a watch, especially its amplitude-related isochronism, is extremely sensitive to the hairspring clearance at the regulator assemblies, and this clearance is difficult to control precisely.

[0011] In some existing devices, an adjustable stop is used to clamp the hairspring to eliminate backlash, especially during hairspring operation. In this case, the timekeeping rate is first adjusted by moving the regulator assembly chuck, and then the hairspring is clamped by the chuck. However, clamping the hairspring by the regulator assembly chuck creates stress on the hairspring, leading to timing errors, especially those caused by hairspring coil misalignment. Furthermore, eliminating backlash also changes the timekeeping rate, and once the hairspring is clamped, the timekeeping rate cannot be fine-tuned by moving the regulator assembly chuck along the hairspring.

[0012] Some hairsprings also include built-in calibration devices. The running speed of such hairsprings is not adjusted by changing the effective length of the hairspring, but rather by applying a force or torque to a flexible element connected in series with the hairspring. This method changes the stiffness of the flexible element, and thus the stiffness of the hairspring as a whole (i.e., the combination of the ribbon and the flexible element). By adjusting the stiffness of the hairspring, the running speed of the regulating mechanism can be adjusted. For example, such hairsprings with flexible elements are described in patent applications EP4009115 and CH0700385 / 2021.

[0013] However, during operation, the aging of internal components of the speed regulating mechanism can interfere with the mechanism, causing changes in its oscillation frequency. These changes in oscillation frequency alter the speed regulation mechanism's travel rate. This phenomenon is known as travel rate drift in the speed regulating mechanism. Summary of the Invention

[0014] The present invention aims to overcome all or part of the above-mentioned defects by providing a watch regulating mechanism, wherein the hairspring of the regulating mechanism is equipped with a device for compensating for the drift of the running rate of the regulating mechanism.

[0015] To achieve this objective, the present invention relates to a rotary regulating mechanism for a watch movement, the regulating mechanism comprising an oscillating mass (e.g., a balance wheel) and a hairspring comprising a flexible strip wound into multiple turns, the strip having a preset stiffness for causing the oscillating mass to rotate and oscillate, the strip comprising an outer end.

[0016] The invention is characterized in that the speed regulating mechanism includes an elastic device for compensating for timekeeping rate drift, the elastic device being configured to adapt its own stiffness according to the aging of the speed regulating mechanism to reduce timekeeping rate drift; the elastic device includes an elastic element and a prestressing mechanism, the elastic element connecting its outer end to a first support fixed relative to the watch movement, and the prestressing mechanism applying a variable force or torque to the elastic element, the force or torque decreasing over time.

[0017] Such elastic devices can compensate for the slowdown in the speed control mechanism caused by component aging and wear. In fact, as the force or torque applied to the elastic element decreases, the stiffness of the elastic element increases, thereby increasing the speed control mechanism's operating speed.

[0018] With the help of this invention, the aging effect can be compensated, so that the running time rate can be kept basically constant, or at least a large drop in the running time rate can be avoided.

[0019] According to one specific embodiment of the present invention, the prestressing mechanism includes a spring portion connected to an elastic element, the spring portion transmitting the force or torque to the elastic element.

[0020] According to one specific embodiment of the present invention, the prestressing mechanism includes a deformable body that comes into at least partial contact with a spring portion during deformation.

[0021] According to one specific embodiment of the present invention, the deformable body comprises a stress-relaxed material that undergoes stress relaxation with aging.

[0022] According to one specific embodiment of the invention, the stress relaxation material comprises a metal or a thermoplastic polymer, wherein the metal is, for example, magnesium, copper, zinc or nickel, and the thermoplastic polymer is, for example, a polyolefin, preferably polypropylene or polyethylene.

[0023] According to one specific embodiment of the present invention, the spring portion includes a first flexible blade connected to an elastic element.

[0024] According to one specific embodiment of the present invention, the spring portion includes a translation stage connected to a first flexible blade, and the deformable body is in contact with the translation stage.

[0025] According to one specific embodiment of the present invention, the speed regulating mechanism extends substantially in the same plane.

[0026] According to one specific embodiment of the present invention, the elastic element includes a suspended point mass block and a pair of non-crossing blades, the pair of non-crossing blades connecting the suspended point mass block to a first fixed support.

[0027] According to one specific embodiment of the present invention, the prestressing mechanism is connected to a suspended point mass block to apply the force or torque to the suspended point mass block.

[0028] The present invention also relates to a watch movement comprising the above-described regulating mechanism. Attached Figure Description

[0029] The objects, advantages, and features of the invention will become clearer by referring to the accompanying drawings, which are given by way of non-limiting example only, in which:

[0030] - Figure 1 A top view of the speed regulating mechanism according to a first embodiment of the present invention in a first configuration is schematically shown;

[0031] - Figure 2 The schematic diagram shows the second configuration. Figure 1 Top view of the speed regulating mechanism;

[0032] - Figure 3 A graph showing the stress on a material as a function of time, and

[0033] - Figure 4 This is a graph showing the change in force applied to the elastic element by the prestressed mechanism over time. Detailed Implementation

[0034] Figure 1 and Figure 2 An embodiment of the speed regulating mechanism according to the present invention is shown.

[0035] The speed regulating mechanism 1 includes a hairspring, which comprises a flexible strip 2 wound into multiple turns. The flexible strip 2 includes an outer end 9 and an inner end 8.

[0036] The speed regulating mechanism 1 includes an oscillating mass block (not shown in the figures), such as a ring-shaped balance wheel, which is connected to the inner end 8 of the belt 2. The belt 2 has a preset stiffness to enable the oscillating mass block to achieve rotational oscillation motion. For example, the oscillating mass block includes an axially rotating pendulum shaft, and the inner end 8 of the belt 2 is connected to the pendulum shaft.

[0037] Preferably, except for the oscillating mass block that oscillates in a parallel plane above the hairspring, the rest of the structure of the speed regulating mechanism 1 is basically in the same plane.

[0038] According to the present invention, the speed regulating mechanism 1 includes an elastic device 10, which is used to compensate for the drift of the running speed accompanied by aging, so as to adjust the running speed and reduce the drift of the running speed.

[0039] The elastic device 10 includes an elastic element 5 connecting its outer end 9 to a support 7 (e.g., a movement plate), which is fixed relative to the watch movement. The elastic device 10 also includes a prestressing mechanism 6 for applying a variable force or torque to the elastic element 5 according to a target running rate setting.

[0040] In this example, the elastic element 5 includes a suspended point mass 3 and a pair of non-crossing blades 4 connecting the suspended point mass 3 to the fixed support 7. The suspended point mass 3 is, for example, a cylinder with a height and diameter substantially equal, and the non-crossing blades 4 are arranged divergently from the suspended point mass 3 to the fixed support 7.

[0041] The elastic element 5 is set as an extension of the flexible strip 2, wherein the hairspring and the elastic element 5 are arranged adjacent to each other, but they will not come into contact during the oscillation of the oscillating mass.

[0042] The prestressing mechanism 6 is designed to apply force or torque to the suspended point mass block 3.

[0043] The prestressing mechanism 6 includes a spring portion comprising a flexible blade 11 connected to a suspended point mass block 3. The flexible blade 11 preferably extends along the axis of symmetry of the elastic element, for example tangent to the strip 2 of the hairspring, and slightly offset from the outer end 9.

[0044] In this embodiment, the spring portion of the prestressing mechanism 6 includes a translation platform comprising an L-shaped first movable element 12 and a second support 13 designed to be fixed relative to the mechanism. The first movable element 12 is connected to a flexible blade 11 via one end of a first arm in the L-shape. A rounded protrusion 23 is provided on the outer side of the second arm in the L-shape. The translation platform also includes two substantially parallel flexible blades 14 for connecting the first movable element 12 to the second fixed support 13.

[0045] The prestressing mechanism 6 also includes a deformable body 15, which applies a variable force or torque depending on aging to the movable element 12 of the spring portion.

[0046] In this example, the deformable body 15 is elongated and positioned substantially perpendicular to the axis of the flexible blade 11 of the spring portion, such that the free portion 24 contacts the protrusion 23 on the second arm of the L-shape. The deformable body 15 has a fastening end 25 opposite to the free end 24.

[0047] exist Figure 1 In the slightly deformed configuration, the free end 24 of the deformable body 15 contacts the protrusion 23, and the force applied to the first movable element 12 is minimal. Therefore, in this configuration, the stiffness of the elastic element 5 changes very little, and the travel speed of the speed regulating mechanism changes only slightly.

[0048] exist Figure 2 In this configuration, the fastening end 25 is fixed below the translation stage, and relative to it... Figure 1 The position in the middle has The offset causes the deformable body 15 to bend. The deformable body 15 thus exerts a large force on the protrusion 23 of the translation stage. .

[0049] The free part 24 pushes the first movable element 12, causing the first flexible blade 11 to transmit force or torque to the suspended point mass block 3, which reduces the stiffness of the pair of non-crossing blades 4. Conversely, if the deformable body 15 is straightened, the force applied to the suspended point mass block 3 decreases, thereby increasing the stiffness of the pair of non-crossing blades 4.

[0050] According to the present invention, the deformable body 15 at least partially comprises a stress-relaxation material. Preferably, the deformable body 15 is entirely made of the stress-relaxation material.

[0051] The Young's modulus of such stress-relaxed materials decreases over time. In other words, when a material is subjected to constant deformation, the resulting stress and force decrease over time. Therefore, when a material is subjected to a force that generates deformation stress, the amount of deformation will increase over time, provided that the magnitude and orientation of the force remain constant.

[0052] Materials possessing this property can be of various types, such as metals like magnesium, copper, zinc, and nickel. Stress-relaxed polymers, such as polyolefin thermoplastics like polyethylene and polypropylene, can also be used.

[0053] The stress-time relationship of these materials can be described by an exponential decay function:

[0054]

[0055] in, This is called the relaxation time constant. The relaxation time constant is material-dependent, and different materials have different relaxation time constants. Materials with suitable relaxation time constants can be selected to compensate for travel rate drift.

[0056] In this case, the force exerted by the deformable body 15 on the translation stage The stiffness of the elastic element 5 will increase over time, thus increasing the travel speed of the speed regulating mechanism. This increase in travel speed can compensate for the travel speed loss caused by aging of other components in the speed regulating mechanism.

[0057] As the deformable body 15 ages, the force exerted by the first free portion 24 on the protrusion 23 gradually decreases, and consequently, the force exerted on the first movable element 12 decreases simultaneously. The first movable element 12 moves under the guidance of the first translation stage. As a result, the force exerted on the elastic element 5 by the first flexible blade 11 gradually decreases. The stiffness of the elastic element 5 increases with aging time, and the running speed of the speed regulating mechanism 1 also increases accordingly, thereby compensating for the loss of running speed caused by component aging.

[0058] Figure 3 This shows the stress within the material. The graph shows, in particular, the initial setting time of the travel rate. Relaxation time after material aging for a certain period of time Between and It is clear that the stress gradually decreases over time.

[0059] Figure 4 This shows the initial setting time of the running time rate. To the relaxation moment Between these points, the force exerted by the deformable body 15 on the translation stage Initial force Force greater than the relaxation phase The compression on the elastic element 5 decreases accordingly, causing the speed regulating mechanism to increase its travel rate. This increase in travel rate can compensate for the aging effect of the speed regulating mechanism that causes the travel rate to decrease.

[0060] The present invention also relates to a watch movement (not shown in the accompanying drawings), the movement comprising a rotary regulating mechanism 1 as described above.

[0061] Of course, the present invention is not limited to the embodiments described with reference to the accompanying drawings. Various alternative embodiments may be considered without departing from the scope of protection of the present invention.

Claims

1. A regulating mechanism (1) for a watch movement, comprising an oscillating mass, such as a balance wheel, and a hairspring, the hairspring comprising a flexible strip (2) wound into multiple turns, the strip (2) having a preset stiffness to enable the oscillating mass to achieve rotational oscillation motion, the strip (2) comprising an outer end (9), characterized in that, The speed regulating mechanism (1) includes an elastic device for compensating for timekeeping rate drift, the elastic device being configured to adapt its own stiffness according to the aging of the speed regulating mechanism; the elastic device includes an elastic element (5) and a prestressing mechanism (6), the elastic element (5) connecting the outer end (9) to a first fixed support (7) fixed relative to the watch movement, the prestressing mechanism (6) for applying a variable force or torque to the elastic element (5), wherein the force or torque decreases over time.

2. The speed regulating mechanism according to claim 1, characterized in that, The prestressing mechanism (6) includes a spring portion connected to the elastic element (5), which transmits the force or torque to the elastic element (5).

3. The speed regulating mechanism according to claim 1 or 2, characterized in that, The prestressed mechanism (6) includes a deformable body (15) that comes into at least partial contact with the spring portion during deformation.

4. The speed regulating mechanism according to claim 3, characterized in that, The deformable body (15) includes a stress-relaxed material that undergoes stress relaxation with aging.

5. The speed regulating mechanism according to claim 3, characterized in that, The stress relaxation material includes a metal or a thermoplastic polymer, such as magnesium, copper, zinc or nickel, and such as a polyolefin, preferably polypropylene or polyethylene.

6. The speed regulating mechanism according to any one of the preceding claims, characterized in that, The spring portion includes a first flexible blade (11) connected to the elastic element (5).

7. The speed regulating mechanism according to claim 6 and any one of claims 3-4, characterized in that, The spring portion includes a translation stage connected to the first flexible blade (11), and the deformable body is in contact with the translation stage.

8. The speed regulating mechanism according to any one of the preceding claims, characterized in that, The speed regulating mechanism (1) extends substantially in the same plane.

9. The speed regulating mechanism according to any one of the preceding claims, characterized in that, The elastic element (5) includes a suspended point mass block (3) and a pair of non-crossing blades (4) that connect the suspended point mass block (3) to the first fixed support (7).

10. The speed regulating mechanism according to claim 9, characterized in that, The prestressing mechanism (6) is connected to the suspended point mass block (3) to apply the force or torque to the suspended point mass block (3).

11. A watch movement, characterized in that, The watch movement includes a regulating mechanism (1) according to any one of the preceding claims.

Images