Method for adjusting the rate of a timepiece's timekeeping mechanism using a laser

Abstract

The invention relates to a method for adjusting the rate difference of a time control mechanism (10) in a timepiece movement, the time control mechanism (10) comprising an inertial mass (5), for example a balance, and an elastic return means (2), for example a spring, for returning the inertial mass (5), the elastic return means (2) being configured to enable an oscillating movement of the inertial mass (5), the method comprising the following steps: adding material to and / or removing material from the inertial mass (5) by using a laser (7) to project material (9).

Description

Technical Field

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

[0002] More specifically, this invention relates to a method for adjusting the time difference using a laser-controlled speed regulation mechanism. Background Technology

[0003] In most mechanical watches, the energy required to rotate the hands (e.g., the minute and hour hands) is stored in the mainspring barrel and then distributed by the balance spring system, which consists of a flywheel called the balance wheel and a spirally wound ribbon spring called the hairspring.

[0004] The inner end of the hairspring is attached to the spindle that rotates with the balance wheel; the outer end of the hairspring is attached to the hairspring stud mounted on the outer stud retainer, which itself is attached to the fixed bridge plate (or balance plate).

[0005] The rotation of the balance wheel is maintained by the escapement mechanism, whose oscillations are counted. The escapement mechanism includes an escape fork driven by a low-amplitude oscillating movement, which has two escape fork pads that engage with the teeth of the escape wheel. When engaged, the escape wheel is forced to rotate in steps at a frequency determined by the oscillation frequency of the escape fork, while the oscillation frequency of the escape fork itself is adjusted to the oscillation frequency of the balance wheel system.

[0006] In a traditional escapement mechanism, the oscillation frequency is approximately 4 Hz, or about 28,800 vibrations per hour (A / h). Skilled watchmakers strive to ensure that the balance wheel oscillates at the same and stable intervals (meaning the time difference remains constant).

[0007] The usual practice is to adjust the balance wheel's time difference by adjusting the effective length of the hairspring. The effective length of the hairspring is defined as the bending length between the inner end of the hairspring and a measuring point located near the outer end of the hairspring. This measuring point is usually defined by a pair of stops carried by a key mounted on the regulator assembly.

[0008] An assembly consisting of a bridge, regulator assembly, key, outer stud holder, hairspring stud, spindle, hairspring, and balance wheel is commonly referred to as a "regulating mechanism." Examples of regulating mechanisms are provided in international application WO2016 / 192957 and European patent EP2876504, both of which have been granted to watch manufacturer ETA.

[0009] Another method to adjust the time difference of the balance wheel is to change its inertia. This inertia can be altered using radial screws and eccentric inertia blocks. The inertia of the balance wheel can be changed by tightening or loosening one or more screws or eccentric inertia blocks.

[0010] Other adjustment methods include adding or removing material from the balance wheel to alter its inertia. This allows for adjustment of the time difference in the regulating mechanism.

[0011] However, in most cases, a regulating device needs to be built into the movement, which means that the configuration of the regulating mechanism needs to be significantly changed. These changes result in huge manufacturing and development costs.

[0012] Furthermore, these adjustment mechanisms require opening the watch case. Opening the case causes pressure changes, which negatively impacts the measurement and adjustment of timekeeping accuracy. Summary of the Invention

[0013] The present invention aims to overcome all or part of the above-mentioned disadvantages by providing a method for adjusting the time difference of the speed regulating mechanism, which does not require major changes to the configuration of the speed regulating mechanism and can be used to perform such adjustment from outside the closed watch case.

[0014] Therefore, the present invention relates to a method for adjusting a speed regulating mechanism of a watch movement, the watch movement including an inertial mass and an elastic reset device for resetting the inertial mass, the inertial mass being, for example, a ring balance wheel, and the elastic reset device being, for example, a hairspring, the elastic reset device being configured to enable the inertial mass to oscillate.

[0015] A significant feature of this invention is that the method includes the steps of adding material to and / or removing material from the inertial mass by laser projection.

[0016] This invention provides a method, unprecedented to date, for adjusting the time difference of a speed regulating mechanism with extremely high precision. Furthermore, since the components occupy little space within the movement, no major modifications to the movement are required.

[0017] Furthermore, this method can be used from the outside of the watch case, specifically by guiding a laser through the case.

[0018] According to a specific embodiment of the present invention, material removal using a laser is achieved by removing material from a material layer deposited beneath the inertial mass.

[0019] According to a specific embodiment of the present invention, the inertial mass is able to transmit the wavelength of the laser, so that the laser can pass through the inertial mass to reach the fusible material layer.

[0020] According to one specific embodiment of the invention, a laser adds material from a support containing material deposited in a material layer, the support being arranged above an inertial mass relative to the laser source.

[0021] According to a specific embodiment of the present invention, the support member is able to transmit the wavelength of a laser.

[0022] According to a specific embodiment of the present invention, the material is selected from gold, platinum, tungsten, rhenium, rhodium or iridium.

[0023] According to a specific embodiment of the present invention, the addition or removal step is performed simultaneously with the oscillation of the inertial mass, and the laser is synchronized with the oscillation of the inertial mass.

[0024] According to a specific embodiment of the present invention, the method includes a preparatory step in which the oscillation frequency and / or amplitude of an inertial mass are measured, and the deviation of the travel time difference relative to a predetermined value is determined.

[0025] According to one specific embodiment of the present invention, a camera is used to measure the oscillation frequency optically, or a microphone is used to measure the oscillation frequency acoustically.

[0026] According to a specific embodiment of the present invention, the steps of adding material to and / or removing material from the inertial mass are performed through the back cover of the watch case, the regulating mechanism being arranged inside the watch case and closed by the back cover, the back cover being transparent to the wavelength of the laser.

[0027] According to a specific embodiment of the present invention, the steps of adding material to and / or removing material from the inertial mass are performed through the watch crystal, which is capable of transmitting the wavelength of a laser.

[0028] The present invention also relates to a speed regulating mechanism for a watch movement, the speed regulating mechanism comprising an inertial mass and an elastic device for resetting the inertial mass, the inertial mass being, for example, a balance wheel, and the elastic resetting device being configured to enable the inertial mass to oscillate.

[0029] A notable feature of this speed control mechanism is that it includes a first component and a second component. The first component is at least partially provided with a layer of fusible material, and the first component is transparent to the wavelength of a laser, which is capable of transferring the material onto the second component.

[0030] According to a specific embodiment of the present invention, the first component is the inertial mass of the speed regulating mechanism, and the second component is a support member arranged below the inertial mass.

[0031] According to a specific embodiment of the present invention, the first component is a support member arranged above the inertial mass, and the second component is the inertial mass.

[0032] The present invention also relates to a watch movement including the regulating mechanism.

[0033] The present invention also relates to a timepiece, such as a wristwatch, comprising a case and a timepiece movement disposed within the case.

[0034] According to a specific embodiment of the present invention, the watch case is provided with a back cover, which is transparent to the wavelength of a laser. Attached Figure Description

[0035] The objects, advantages, and features of the invention will become apparent from the various embodiments provided by way of non-limiting example only with reference to the accompanying drawings, in which:

[0036] Figure 1 A schematic top view of a prior art speed control mechanism is shown.

[0037] Figure 2 Showing the arrangement in the watch movement Figure 1 A schematic side view of the speed regulating mechanism.

[0038] Figure 3 A schematic side view of a portion of a first embodiment of the speed regulating mechanism is shown during the execution of the regulating method according to the invention.

[0039] Figure 4 A schematic side view of a portion of a second embodiment of the speed regulating mechanism is shown during the execution of the regulating method according to the invention.

[0040] Figure 5 A schematic side view of a portion of a third embodiment of the speed regulating mechanism is shown during the execution of the regulating method according to the invention.

[0041] Figure 6 A side view of a clock including a speed regulating mechanism is shown during the execution of the regulating method according to the invention. Detailed Implementation

[0042] The present invention relates to a method for adjusting the time difference of the regulating mechanism 1 in a watch movement.

[0043] exist Figure 1 and Figure 2 In this design, the speed regulating mechanism 1 includes an inertial mass 5 (e.g., a balance wheel) and a resilient reset device 2 (e.g., a hairspring) for resetting the inertial mass 5. The resilient reset device 2 is configured to enable the inertial mass 5 to oscillate. The speed regulating mechanism 1 needs to be adjustable to change the timekeeping error of the movement on which it is mounted.

[0044] According to the present invention, the method includes the steps of adding material to or removing material from an inertial mass by laser projection.

[0045] For example, materials can be projected using a LIFT (Laser-Induced Forward Transfer) device.

[0046] This device works by using a laser to precisely target a substrate with multiple layers of material deposited on it, removing at least a portion of the material from the substrate and projecting it onto another substrate. The following literature describes this method:

[0047] - Printing Method for Long Flight Distance by Laser-Induced Forward Transfer, H. Suhara, J. Aoto, M. Iwata, Journal of Laser Micro / nanoengineering, Vol. 15, No. 2, 2020.

[0048] - Laser-Induced Forward Transfer: A high-resolution additive manufacturing technology, P. Delaporte, AP. Alloncle, Optics & Laser Technology, 78(2016) 33-41.

[0049] - Laser-Induced Forward Transfer: A method for Printing Functional Inks, JM Fernandez-Pradas, P. Serra, and

[0050] - Selective surface metallization by laser (Laser selective surface metallization), A. Bahouka, Techniques de l'ingénieur (Engineer's Technical Handbook), 10 December 2017, M 1643 V2.

[0051] Using this method, material can be added to or removed from the inertial mass 5 to change its inertial characteristics, thereby correcting the time difference of the speed regulating mechanism 1.

[0052] In fact, adding or removing material from the inertial mass 5 alters its inertia, thereby changing its oscillation frequency. This causes a correction in the travel time of the speed control mechanism.

[0053] Figure 3 A portion of a first embodiment of a speed regulating mechanism 10 that can be used with the method according to the invention is shown, particularly when adding material to an inertial mass 5.

[0054] When material is added to the inertial mass 5, the addition is performed via a support 6 containing fusible material. In addition to the inertial mass 5, the speed regulating mechanism 10 also includes a support 6 for the fusible material.

[0055] The support 6 includes a body that transmits laser wavelengths, beneath which a material layer 8 is deposited. This body is, for example, synthetic sapphire (e.g., Al₂O₃), silicon glass, quartz, or single-crystal silicon. The support 6 is positioned between the laser source and the inertial mass 5. Therefore, the laser light passes through the support 6 to reach the material layer 8, causing fragments of the material layer 8 to detach from the support 6 and fall onto the inertial mass 5.

[0056] Preferably, the distance between the support member 6 and the inertial mass body 5 is less than 10 mm, more preferably less than 5 mm or even less than 2 mm.

[0057] The support member 6 is, for example, a plate whose shape at least partially corresponds to the shape of the inertial mass 5.

[0058] Alternatively, the support member 6 is a bridge plate on which the speed regulating mechanism 1 is mounted, such as a swing plate.

[0059] For example, the support member 6 is press-fitted onto the swing clamp plate, and the speed regulating mechanism 1 is installed on the swing clamp plate.

[0060] Preferably, material 9 is selected from gold, platinum, tungsten, rhenium, rhodium or iridium.

[0061] For example, the frequency range of the laser is from the infrared spectrum to the visible spectrum and then to the ultraviolet spectrum. Therefore, the main body of the support 6 is transparent to the infrared spectrum and / or the visible spectrum and / or the ultraviolet spectrum. The wavelength of the laser is between 350 nm and 1100 nm, preferably between 500 nm and 1000 nm, or even between 1000 nm and 1100 nm.

[0062] For example, laser 7 is aimed at the upper surface of support 6 and passes through the main body to reach material layer 8. Under the action of laser 7, the material will melt, evaporate, or even fall off in fragments, depending on the laser used and the material.

[0063] This results in the projection of material 9, which detaches from support 6 and deposits onto inertial mass 5. Laser 7 moves along material layer 8, transferring the desired amount of material onto inertial mass 5. For example, material is deposited on the circular portion of the balance wheel. Thus, the deposited material makes the balance wheel heavier, thereby changing its oscillation frequency.

[0064] Support 6 may comprise multiple layers of different densities to facilitate selection of the amount of material to be transferred. As a variation, support 6 may also be replaced by multiple support members, each having a layer of material of a different density.

[0065] The support 6 may include a single material layer 8 or a stack of multiple material layers to improve the adhesion of the transferred material to the inertial mass 5. For example, an Au or Pt layer may be used as an adhesion layer on a Ti or Cr layer.

[0066] When the laser 7 is used to remove material, the material 9 deposited below the inertial mass 5 of the speed control mechanism 20 is removed, such as... Figure 4 As shown. Preferably, the inertial mass 5 includes a body that is transparent to the laser beam, and a material layer 12 is deposited beneath it.

[0067] In this configuration, the laser 7 passes through the main body and reaches the material layer 12 deposited beneath it. A portion of the material 9 in the material layer 12 is projected onto the support 11 of the speed control mechanism 20, which is positioned below the inertial mass 5. Therefore, in this variation of the method, the inertial mass 5 becomes lighter, thereby altering its oscillation frequency to adjust the travel time difference of the speed control mechanism 20.

[0068] exist Figure 5 In this embodiment, the two preceding embodiments are combined, allowing material to be added to or removed from the inertial mass 5 as needed.

[0069] In this configuration, the speed control mechanism 30 includes a first support 6 positioned above the inertial mass 5 and a second support 11 positioned below the inertial mass 5. Both the inertial mass 5 and the first support 6 comprise a body that is transparent to the wavelength of the laser 7. Furthermore, they both include material layers 8 and 12 deposited beneath the bodies.

[0070] Preferably, material layers 8 and 12 are not stacked so that the laser 7 can reach them separately.

[0071] Therefore, by selecting to point the laser 7 at the first support 6 or the inertial mass 5, material can be added to or removed from the inertial mass 5.

[0072] In this configuration, the inertia of the inertial mass 5 can be changed (increased or decreased) to adjust the oscillation frequency of the balance wheel.

[0073] In a first exemplary embodiment of the method, a nanosecond laser is used. The material is gold deposited on a sapphire support, while the balance wheel is made of brass covered with a CuBe layer.

[0074] The laser 7 is actuated in the form of pulses, the duration of which is, for example, between 1 fs and 500 ns, preferably between 1 ns and 400 ns.

[0075] The energy density of the laser pulse is between 0.1 J / cm². 2 With 100J / cm 2 Between, preferably between 0.5 J / cm 2 With 50J / cm 2 Between, more preferably between 1 J / cm 2 With 15J / cm 2 between.

[0076] The laser power is between 5W and 30W, preferably between 10W and 20W.

[0077] For example, the laser frequency is between 50 kHz and 300 kHz, preferably between 150 kHz and 250 kHz.

[0078] For widths between 20µm and 80µm, these parameters result in lengthwise material deposition rates between 0.05µg / mm and 1µg / mm.

[0079] Femtosecond lasers can also be used, with power between 0.1W and 2W, preferably between 0.2W and 1W, but the resulting layers will extend further outward. For example, the laser pulse duration is 260 fs.

[0080] The laser frequency is between 10 kHz and 250 kHz, preferably between 150 kHz and 250 kHz.

[0081] For example, the material is gold arranged on a sapphire support. The result is that the material layer is transferred to the brass balance wheel.

[0082] Preferably, the position of the laser 7 can be changed relative to the support 6 and / or the inertial mass 5. Thus, the laser 7 can select regions in the material layers 8 and / or 12 that have not yet been affected.

[0083] Preferably, the deposition or removal step is performed when the inertial mass 5 stops. In this case, the inertial mass 5 does not oscillate, which facilitates the deposition or removal of material by the laser 7.

[0084] In a variant embodiment, the deposition or removal step is performed simultaneously with the oscillation of the inertial mass 5. For this purpose, the laser pulse is synchronized with the oscillation of the inertial mass 5.

[0085] Alternatively, the laser pulses are distributed throughout the entire oscillation period of the inertial mass 5 without specific synchronization.

[0086] Preferably, the method includes a preliminary step of measuring the oscillation frequency and / or amplitude of the inertial mass 5. For example, the oscillation frequency can be measured optically using a camera, acoustically using a microphone (e.g., a Witchi microphone), or by any other measurement method known to those skilled in the art. Preferably, the oscillation frequency is measured at all four standard locations to correct for any potential imbalances in the inertial mass 5.

[0087] The method also includes the step of determining the deviation of the timekeeping error from a predetermined value. This determines the difference between the actual timekeeping error of the movement and the expected timekeeping error.

[0088] These two steps are used to determine the amount of material to be added to or removed from the inertial mass 5 in order to adjust the required travel time difference.

[0089] Furthermore, the steps of adding and / or removing material from the inertial mass 5 can be performed through the back cover 16 of the watch case (not shown in the figure), such as... Figure 6 As shown. The watch case houses the watch movement 15, which is equipped with the regulating mechanism according to the present invention.

[0090] The watch case is sealed by a back cover 16, which is preferably removable. In order for the laser 7 to pass through, the back cover 16 at least partially comprises glass that transmits the wavelength of the laser 7.

[0091] This avoids the need to open the watch case to change the timekeeping error of the regulating mechanism. The watch case includes a cavity for housing the watch movement, within which the regulating mechanism is located.

[0092] Of course, the present invention is not limited to the embodiments of the speed regulating mechanism described with reference to the accompanying drawings, and various modifications can be conceived without departing from the scope of the present invention.

Claims

1. A method for adjusting the time difference of a regulating mechanism (10, 20, 30) in a watch movement, said regulating mechanism (10, 20, 30) comprising an inertial mass (5) and an elastic reset device (2) for resetting said inertial mass (5), said inertial mass (5) being, for example, a balance wheel, said elastic reset device (2) being, for example, a hairspring, said elastic reset device (2) being configured to enable said inertial mass (5) to oscillate, characterized in that, The method includes the following steps: adding material to the inertial mass (5) and / or removing material from the inertial mass (5) by projecting material (9) using a laser (7).

2. The method according to claim 1, characterized in that, Material removal using the laser (7) is achieved by removing material (9) deposited in the material layer beneath the inertial mass (5).

3. The method according to claim 2, characterized in that, The inertial mass (5) is able to transmit the wavelength of the laser (7), so that the laser (7) can pass through the inertial mass (5) and reach the material layer of the material (9).

4. The method according to any one of the preceding claims, characterized in that, The laser (7) adds material from a support containing material (9) deposited in a material layer, the support being arranged above the inertial mass (5) relative to the laser source.

5. The method according to claim 4, characterized in that, The support member is able to transmit the wavelength of the laser (7).

6. The method according to any one of the preceding claims, characterized in that, The material (9) is selected from gold, platinum, tungsten, rhenium, rhodium or iridium.

7. The method according to any one of the preceding claims, characterized in that, The addition or removal steps are performed simultaneously with the oscillation of the inertial mass (5), and the laser (7) is synchronized with the oscillation of the inertial mass (5).

8. The method according to any one of the preceding claims, characterized in that, The method includes a preparatory step in which the oscillation frequency and / or amplitude of the inertial mass (5) is measured, and the deviation of the travel time difference from a predetermined value is determined.

9. The method according to any one of the preceding claims, characterized in that, The steps of adding material to and / or removing material from the inertial mass (5) are performed through the back cover (16) of the case (15), in which the speed regulating mechanism (10, 20, 30) is arranged, the case (15) being closed by the back cover (16), the back cover (16) being transparent to the wavelength of the laser.

10. A speed regulating mechanism for a watch movement, the speed regulating mechanism comprising an inertial mass (5) and an elastic reset device (2) for resetting the inertial mass (5), the inertial mass (5) being, for example, a balance wheel, the elastic reset device (2) being configured to enable the inertial mass (5) to oscillate, characterized in that, The speed control mechanism includes a first component, which is at least partially provided with a material layer of a material (9), the first component being able to transmit the wavelength of a laser (7), the laser (7) being able to transfer the material (9) onto a second component.

11. The speed regulating mechanism according to claim 10, characterized in that, The first component is the inertial mass (5) of the speed regulating mechanism, and the second component is a support member arranged below the inertial mass (5).

12. The speed regulating mechanism according to claim 10, characterized in that, The first component is a support arranged above the inertial mass (5), and the second component is the inertial mass (5).

13. A watch movement, characterized in that, The watch movement includes a regulating mechanism (10, 20, 30) according to any one of claims 10 to 12.

14. A timepiece, such as a wristwatch, said timepiece comprising a case, characterized in that, The watch includes a watch movement (15) according to claim 13, the watch movement (15) being arranged in the watch case.

15. The clock according to claim 14, characterized in that, The watch case is provided with a back cover (16) that is transparent to the wavelength of the laser (7).

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