Classifications

• • G—PHYSICS
  • G04—HOROLOGY
  • G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
  • G04D7/00—Measuring, counting, calibrating, testing or regulating apparatus
  • G04D7/08—Measuring, counting, calibrating, testing or regulating apparatus for balance wheels
• • G—PHYSICS
  • G04—HOROLOGY
  • G04D—APPARATUS OR TOOLS SPECIALLY DESIGNED FOR MAKING OR MAINTAINING CLOCKS OR WATCHES
  • G04D7/00—Measuring, counting, calibrating, testing or regulating apparatus
  • G04D7/10—Measuring, counting, calibrating, testing or regulating apparatus for hairsprings of balances

Definitions

• the present invention relates to a method for characterizing the inertia of the balance and the stiffness of the spiral for a pairing of these two elements and form a mechanical assembly, for the regulation of stored energy within a clockwork mechanical movement.
• the present invention also relates to a method of manufacturing a watchmaking regulating member and a regulating member formed according to this method.
• the pairing of the balance and the spiral is made from the measurements of the inertia of the balance (J) and the stiffness of the spiral (C).
• the frequency f of the regulating organ after pairing is given by the relation:
• Various methods are known that allow the measurement of the inertia of the balance and the stiffness of the hairspring based on a comparative and dynamic analysis from a balance and a hairspring.
• the reference beam and the reference balance must respectively have a known stiffness and inertia. This is not the case because there is no measurement method to determine these parameters absolutely or with sufficient accuracy.
• the pairing may be associated or based on the correction of the inertia of the balance to adjust the oscillation frequency of a balance-balance pair. This correction can be achieved by conventional machining techniques (patents since 1957) or by laser techniques (patents since 1999).
• the correction method consists of removing, adding or moving the balance material.
• the balance or balance spring is corrected after or during the dynamic measurement of the frequency of the paired organ.
• the pendulum balance must be minimum.
• the unbalance measurement is performed dynamically in a phase prior to pairing and the
• corrections are made to the balance by removing material by conventional machining methods or laser on targeted points at the serge.
• the so-called "Omegametric" system consists in performing: a classification of the spirals; - a classification of the balancers; a pairing of a pendulum chosen in a particular class, with a hairspring also chosen in a particular class, these classes being compatible with one another. This process imposes a large stock of components and relatively large classes.
• the document CH 12 83368 in the name of the Company of Factories of Joined Spirals also describes the obtaining of a balance-spiral set of desired frequency, from series of previously measured torque spirals and sets of momentary pendulums previously measured inertia.
• the adjustment is done by adding additional masses on the rockers. These balances are provided for a frequency higher than the nominal frequency, so that the correction is done in the one-way addition of material.
• the additional mass is rigid and its center of gravity coincides with that of the balance.
• the addition of additional mass is planned to modify all the pendulums of the same class. Additional masses are classified by moment of moment of inertia ranges.
• the document EP 2 128 723 in the name of Sigatec describes a method in which spirals are classified by measured elastic torque values. Then one chooses among the set of balancers the one whose moment of inertia makes it possible to obtain the frequency of oscillation required with a classified spiral, it is about a pairing.
• the document CH 542 469 A in the name of Ebauches SA describes an addition of material by projection by a micro-doser.
• the present invention is a method for
• the present invention is a method of measuring the inertia and stiffness from volumetric measurements of the balance and the spiral.
• the measurement is not linked to references and is not based on comparisons. She is direct.
• the parameters of the inertia and the stiffness are preferably determined by volumetric measurements made by tomography.
• volumetric can be imagined.
• the volumetric measurement by tomography however has the advantage of also characterizing the interior of the balance spring or balance measured, for example to detect variations in density, and not only the external surface.
• the tomography images are made using electromagnetic radiation absorption shots. Any radiation
• electromagnetic including radiation in the X-ray, terahertz, ultraviolet, visible, infrared, etc., capable of penetrating the material may be used to take the absorption pattern.
• X-rays for example hard radii, i.e. X-rays with an energy greater than 5 keV and a wavelength less than 0.1 - 0.2 nm , are employed.
• wavelengths in the infrared or visible band (400 to 1400 nm) may be used to take snapshots if the material to be analyzed is partially transparent to IR-visible radiation. For example, silicon becomes transparent in the infrared.
• the parameters such as the center of mass of the part, the unbalance for the balance, defects in structures or materials can be determined in addition to the inertia of the balance and the stiffness of the spiral.
• tomographic reconstruction can be used in two ways: by assigning each pixel in three dimensions (called voxel) a density or by determining the surface of the object creating a mesh.
• the mass of each voxel is given by multiplying the density of the material by the volume of the voxel.
• the center of mass (CM) of the sample is calculated by summing the contribution of each voxel.
• the axis of rotation of the pendulum is identified by a shape recognition algorithm of the pendulum assembled or not.
• the magnitude and angle of the unbalance are then given by the position of the CM relative to the axis of rotation.
• the pendulum inertia of the balance is also calculated by summing the contribution of each voxel.
• the inertia tensor is diagonalised by calculating its eigenvalues. It's here greater of these eigenvalues which gives the principal moment of inertia of the pendulum.
• a segmentation algorithm is applied to determine the surface of the object. It is possible to segment the object in its entirety or to separate its components. This results in one or more meshes.
• a mesh is a geometrical modeling of the object by finite elements. It is composed of points characterized by their coordinates and cells, constituting polyhedra connecting these points. A density is assigned to each mesh and it is then possible to calculate its mass, its center of mass and its moment of inertia with respect to the axis of rotation. The unbalance is then calculated in the same way as mentioned above.
• the stiffness C is determined by:
• a measurement step allows for a series of control but can also point the defective areas or to rectify.
• the invention allows to define in one measure, the inertia, as well as the unbalance of a pendulum assembled or not, and the angular position of the unbalance to correct the unbalance (balancing) and adapt the inertia if necessary.
• the correction of the inertia and unbalance of the balance (balancing) is performed in one and the same step.
• the correction is done by removal, addition or displacement of material by a conventional machining method or laser.
• the invention allows to define the stiffness of a spiral with or without ferrule. This, partially or in its total geometry.
• the invention makes it possible to industrially produce energy regulators that are sufficiently precise to avoid any adjustment of the system during the start-up of the watch movement.
• the invention is a major innovation in the field of watchmaking because it allows to match the balance and the spiral with inaccurate details with the approaches of the state of the art.
• the industrial pairing process will no longer be based on classes as is currently the case but on physical values that will allow precise pairing.
• Figure 1 illustrates a pendulum
• Figure 2 illustrates a spiral
• Figure 3 illustrates tomographic measuring equipment.
• Example (s) of embodiment of the invention
• Figures 1 and 2 respectively illustrate a rocker 6 and a spiral 7 of a watch movement.
• a volumetric measuring device is illustrated in FIG.
• the method consists in determining the density distribution of the volume of the sample 4 (that is to say, the spiral wound or not, the balance, or both elements simultaneously) by exposing it to a source of electromagnetic radiation 1 that penetrates the sample material.
• a radiation intensity detector or sensor 2 records X-rays or images that are images resulting from the absorption of the electromagnetic wave.
• the sample is positioned between the source and the detector using a positioning platform 3. After each exposure, the snapshot is stored and the sample rotates about an axis so as to take a multitude of clichés at different angles of view.
• the sample is fixed and the source (s) and / or detector (s) move between each shot.
• the tomographic apparatus has several sources of radiation and several detectors to take pictures at different angles of view without rotation of the sample; in this case it is possible to take the different views simultaneously, or one after the other.
• the complete system is protected by a box 5 absorbing residual radiation. Recorded X-rays are digitally processed to obtain virtual sections of the sample.
• the reconstruction of the sample in 3D makes it possible to visualize the variations of density of the sample. From 3D image processing algorithms, we can calculate different parameters of the sample:
• the invention is in the industrial mode, as follows:
• the measurement of each component is performed statically by means of a tomographic equipment, the measurement is sufficiently precise to ensure the regulating qualities of the system.
• the measurement can be performed independently on a single component, or on assemblies comprising components from different materials, and takes into account materials having galvanic or other layers.
• the invention integrates into a production line and allows to achieve large volumes, while reducing the number
• the inertia and unbalance will be measured, the unbalance will also be positioned on the balance beam. This information will be stored in the database of the line, and will be used for the balancing operation and when assembling to the marker.
• the stiffness measured will be stored in the database of the line. This information will be used during assembly at the marker.
• the final length of the hairspring will be determined from the physical measurement by tomography and adapted for pairing with the pendulum.
• the industrial pairing process will no longer be based on classes as is currently the case but on physical values that will allow precise pairing.
• the correction (balancing and good inertia) will reduce or eliminate component stocks in the line. It is possible to measure by tomography the parameters of the balance and / or the balance before their correction.
• the stiffness of the hairspring must be measured within a tolerance of ⁇ 0.0002 e-7 N.m / rad.
• the inertia of the pendulum must be measured within a tolerance. ⁇ 0.0003 mg * cm 2 .
• the balance of the balance wheel may be measured within a tolerance of ⁇ 2 g * cm 2 .
• the angular position of the unbalance must be within a tolerance of ⁇ 0.1.
• the assembled balance will be balanced on the basis of a static measurement described above, and balancing will be according to a conventional method, or on the point of unbalance and a diametrically opposite point (180 ° ).

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Analysing Materials By The Use Of Radiation (AREA)
• Testing Of Balance (AREA)

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• 2015
  • 2015-03-03 EP EP15708787.5A patent/EP3114535B1/de active Active
  • 2015-03-03 WO PCT/EP2015/054417 patent/WO2015132259A2/fr active Application Filing

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