EP2738625B1 - Timepiece case comprising a metal bellows - Google Patents

Description

The present invention relates to a watch case comprising a case whose at least one opening is closed by a telescope and / or an ice, or by a bottom, and in which at least one of the closing elements of the opening is connected at the middle part by an elastic metal member in the form of a ring or endless frame and of recessed straight section defined by the contour of a non-rectilinear wall of controlled thickness, the ends of which are integral with the periphery of said closure element, respectively of the middle part.

It may be advantageous to make the ice or the bottom of a watch movable relative to the middle part, and without pre-sealing the box, for example to improve impact resistance, or to perform new functions. The solutions proposed in the state of the art are not satisfactory in this respect.

The documents CH630220 and CH686600 describe means for moving an ice at variable frequencies by means of an electromagnet or a piezoresistive element. There is mention of a thin annular ring which makes it possible to elastically suspend the ice. The mobility of the ice relative to the middle part is very limited both in the plane of the ice and in the plane perpendicular to the ice, and the watertightness is not guaranteed by the construction.

It has been proposed in CH 632387 and in the CH 698742 to provide an elastic connecting piece between a sound generator and a watch ice. This connecting piece is formed of several annular segments each having, in section, a rectilinear shape, which has the effect of limiting the amplitude of the moving part associated with this connecting piece.

The document WO 2008027140 describes a mobile (tilting) bezel to activate different functions. The mobility of this bezel is due to a piece of rubber or polyurethane, which however does not provide the seal and which we can doubt the reliability in the long term.

The document EP 0028429 describes a watch case comprising a case in which at least one opening is closed by a telescope and / or an ice-cream, or by a bottom, and in which at least one of the closing elements of the opening is connected to the middle part by a elastic metal member in the form of ring or endless frame and recessed straight section defined by the profile of a non-rectilinear wall whose ends are integral with the periphery of said closure element, respectively of the middle part.

This document also describes that the profile of said non-rectilinear wall forms at least one annular fold oriented perpendicular to the plane of said opening, this annular fold being generated by a curvature whose arc describes an angle of between> 90 ° and 180 °, to give said closure member (1, 11, 21, 18) a freedom of movement relative to the plane of the opening, adapted to a movement in a direction perpendicular to the opening.

The object of the present invention is to give a controlled freedom of movement in direction and amplitude to the closure element mounted on the caseband, bezel and / or ice or bottom, depending on the role that one wishes to give to this closure element.

For this purpose, the subject of the present invention is a watch case according to claim 1.

Advantageously, the profile of said wall comprises a plurality of alternating annular folds whose number is between 2 and 10.

Preferably, the thickness e of said wall is constant and is between 10 .mu.m and 200 .mu.m, the width a of the annular fold is between 0.2mm and 4mm, the pitch p of the annular fold being between> 40 .mu.m and 2.5 mm, to give said closure member freedom of movement, stiffness and orientation controlled with respect to the plane of the opening.

More preferably, the ends of the profile of said wall are sealingly connected to the periphery of said closure element, respectively of the middle part.

According to a preferred embodiment of the invention, seals are mounted between the respective cylindrical ends of said wall adjacent to cylindrical seats of said closure member, respectively of said middle and compression rings or frames in view of to seal the box.

• La figure 1 est une vue partielle en coupe d'une première forme d'exécution;
• la figure 2 est une vue en coupe d'une variante de la figure 1;
• la figure 3 est une vue en coupe du schéma de principe d'une autre forme d'exécution;
• la figure 4 est une vue en coupe d'une forme d'exécution relative à une boîte de montre carrée ou rectangulaire;
• la figure 4a est une vue en perspective éclatée de la figure 4;
• la figure 5 est une vue en coupe d'une utilisation particulière de la boîte de montre selon l'invention;
• la figure 6 est une vue en coupe d'une autre forme d'exécution de l'invention;
• la figure 7 est un schéma d'un soufflet sur lequel sont indiqués les différents paramètres de ce soufflet.

Other features and features of the present invention will become apparent from the following description and accompanying drawings which illustrate, schematically and by way of example, various embodiments and variations of the present invention.

• The figure 1 is a partial sectional view of a first embodiment;
• the figure 2 is a sectional view of a variant of the figure 1 ;
• the figure 3 is a sectional view of the schematic diagram of another embodiment;
• the figure 4 is a sectional view of an embodiment relating to a square or rectangular watch case;
• the figure 4a is an exploded perspective view of the figure 4 ;
• the figure 5 is a sectional view of a particular use of the watch case according to the invention;
• the figure 6 is a sectional view of another embodiment of the invention;
• the figure 7 is a diagram of a bellows on which are indicated the different parameters of this bellows.

The elastic metal member, ring-shaped or endless frame and recessed cross-section defined by the profile of a non-rectilinear wall, preferably substantially constant thickness, the ends of which are secured respectively to the periphery of a closure element and an opening of the middle part of a watch case according to the present invention, forms a bellows comprising at least one annular fold generated by a curvature whose arc describes an angle of between> 90 ° and 180 ° to give said closure member freedom of movement relative to the plane of the opening of the middle part.

Metal bellows are elements formed of a thin metal wall, with a carefully chosen profile to provide flexibility, stiffness and strength to the assembly. There are several types of metal bellows: rolled, hydro-formed, chemically deposited, electro-formed, this list being non-exhaustive.

Electro-formed bellows are particularly interesting. Their manufacturing technique is more than 150 years old, but it is only in recent years that components with complex geometries of low thickness (of the order of ten microns) and well controlled have been obtained. The challenge in thickness control is to play with deposition parameters (eg interelectrode distances, nature of electrodes, agitation and bath chemistry, etc.) so as to minimize variations in thickness due to variations. of current density along a geometry with strong changes of curvature. The precise control of the geometry and the thickness makes it possible to develop bellows with adequate stiffness and able to give the closing element of the opening of the middle part a freedom of movement with respect to the plane of this opening. The companies Servometer or Nicoform are examples of suppliers of miniature electro-shaped bellows. These bellows are described for example in the US 3'187'639 and US 5,932,360 . The websites www.servometer.com or www.nicoform.com also give a lot of information about the technique and the materials used.

Such bellows can be assembled to other rigid parts to facilitate their integration. It must be ensured that the chosen methods of assembly and the materials used are adapted to the constraints that will to undergo the assembly without the associated function being pejorated.

The assemblies can be made by gluing, brazing or welding by electron or laser bombardment, or by a combination of at least two of these methods. If, for example, it is desired to guarantee a seal, the bonding or a solder with tin may prove to be insufficient. In addition, depending on the materials used, too high a temperature in the process can degrade their properties. If the stresses require good corrosion resistance, care must be taken to use suitable materials or pairs of materials.

• Le nickel ordinaire (Ni + cobalt : 99.8%) avec 0.04% de soufre (aspect brillant), et 0.05% d'impuretés (oxygène et carbone) est cassant vers 177°C, cet alliage ne peut pas être soudé. Un nickel à plus bas taux de soufre (pas plus de 0.02%, aspect satiné) résiste mieux que le précédent et peut être soudé. De plus ce dernier présente l'avantage de mieux résister à la corrosion que le nickel ordinaire. Il en va de même pour un nickel à plus fort taux de cobalt (3-10%) qui comporte une dureté plus élevée.
• Une couche mince de cuivre de l'ordre de 3 microns déposée entre deux épaisseurs égales de nickel assure une étanchéité du soufflet sous ultra-haut vide.
• Le plaquage en or du nickel tout comme la réalisation du soufflet en or massif permettent une soudure sans flux à plus haute température. Un tel système est particulièrement avantageux lors de l'assemblage d'un soufflet avec une partie rigide en titane. Les surfaces sont résistantes à la corrosion, et confèrent une bonne conductibilité électrique et sont utiles dans des applications de connectique micro-ondes.
• Le plaquage en zinc est une alternative intéressante à l'or pour des applications de protection contre la corrosion (protection par anode perdue).
• Le plaquage en argent est utile dans des applications de connectique micro-ondes.
• Un revêtement par un film polymère de poly-p-xylylène, communément appelé parylène, de faible permittivité diélectrique, présente une excellente stabilité (résistance aux solvants et endurance thermique). Il est également biocompatible et biostable. Ces propriétés le rendent particulièrement intéressant en tant que barrière à l'environnement (corrosion) et couche isolante.
• L'utilisation de cuivre massif ou d'un alliage de nickel-phosphore peut s'avérer intéressante pour leurs propriétés paramagnétiques (le nickel est ferromagnétique).

The material used for the bellows is typically nickel or different nickel-based alloys with specific properties. Other materials such as gold, bronze, silver, titanium, tin, zinc or copper are possible alternatives, in massive form or as a finishing coating by nickel plating. In addition, there are other polymer base finishes. Taking into account the remarks stated, one can imagine different variants of assembly and association of materials for specific applications. In each case, the materials involved in the geometrical dimensioning of the system must be taken into account in order to obtain adequate stiffness. Some known examples are:

• Ordinary nickel (Ni + cobalt: 99.8%) with 0.04% sulfur (shiny appearance), and 0.05% impurities (oxygen and carbon) is brittle around 177 ° C, this alloy can not be welded. A nickel with a lower sulfur content (not more than 0.02%, satin aspect) withstands better than the previous one and can be welded. In addition, the latter has the advantage of better resisting corrosion than ordinary nickel. The same goes for a nickel to higher rate of cobalt (3-10%) which has a higher hardness.
• A thin layer of copper of the order of 3 microns deposited between two equal thicknesses of nickel ensures a seal of the bellows under ultra-high vacuum.
• The gold plating of nickel as well as the realization of the solid gold bellows allow welding without flux at higher temperatures. Such a system is particularly advantageous when assembling a bellows with a rigid titanium part. The surfaces are resistant to corrosion, and provide good electrical conductivity and are useful in microwave connection applications.
• Zinc plating is an interesting alternative to gold for corrosion protection applications (lost anode protection).
• Silver plating is useful in microwave connection applications.
• A coating with a poly-p-xylylene polymer film, commonly known as parylene, of low dielectric permittivity, has excellent stability (solvent resistance and thermal endurance). It is also biocompatible and biostable. These properties make it particularly interesting as a barrier to the environment (corrosion) and insulating layer.
• The use of solid copper or a nickel-phosphorus alloy can be interesting for their paramagnetic properties (nickel is ferromagnetic).

The form of execution illustrated by the figure 1 relates to the attachment of a watch crystal 1 to close the upper opening of a middle part 2 of a watch case.

The watch glass 1 is connected to the middle part 2 by an elastic metal member 3 in the form of a ring of recessed straight section defined by the profile of a non-rectilinear wall of constant thickness, constituting a metal bellows whose ends 3a, 3b are integral with the periphery of the glass 1, respectively the middle 2. An annular seal 4 surrounds the periphery of the ice and the end 3a of the metal bellows 3. A compression ring 5, for example made of titanium, compresses the annular seal against the periphery of the ice 1. The end 3a of the bellows is thus trapped between the annular seal 4 and the ice 1.

The other end 3b of the bellows 3 is fixed in the same way against a cylindrical portion of the middle part 2 by an annular seal 6 compressed by a titanium ring 7. A bezel 8 is fixed on the middle part by a ring 9 fixed against a carried on the external lateral face of the titanium ring 7.

As can be seen, the ice 1 is held only by one end of the bellows 3, so that it is suspended elastically on the middle part 2. This assembly can then act as a shock absorber; it may be able to switch to enable functions; or else serve as speaker, pressure sensitive system (balance, barometer, etc.), without this enumeration is limiting.

• Une extrémité ou les deux extrémités du soufflet 3 sont assemblées par collage, soudage ou brasage à une bague rigide, voire directement à la carrure, pour faciliter l'intégration du système sur la boîte. Dans le schéma de la figure 2, une bague B, par exemple en titane, qui maintient la glace 1 et son joint 4, est soudée au soufflet, par exemple en or massif. L'autre extrémité côté carrure 2 est pincée avec un joint de compression J entre la lunette et la carrure 2. Cet ensemble est parfaitement étanche et résiste aux sollicitations de l'environnement extérieur.
• On peut aussi réaliser un assemblage dans lequel la glace 11 et la lunette 18 sont solidaires comme schématisé à la figure 3. L'ensemble lunette-glace suspendu à la carrure par le soufflet 23 peut servir à actionner un ou plusieurs poussoirs P, afin de commander les fonctions d'un chronographe, d'opérer un changement rapide de date ou de fuseau horaire, ou de commander toute autre fonction. Sur la même figure, un soufflet S est aussi représenté schématiquement pour relier de façon étanche la couronne de remontage et/ou de mise à l'heure C à la boîte B.

Different variants of the assembly method described in the figure 1 can be imagined:

• One end or both ends of the bellows 3 are assembled by gluing, welding or soldering to a rigid ring or directly to the middle part, to facilitate the integration of the system on the box. In the diagram of the figure 2 , a ring B, by example titanium, which maintains the ice 1 and its seal 4, is welded to the bellows, for example solid gold. The other end side 2 is clamped with a compression joint J between the bezel and the middle 2. This set is perfectly sealed and withstands the stresses of the external environment.
• It is also possible to make an assembly in which the window 11 and the window 18 are integral as shown schematically in FIG. figure 3 . The set ice-glass suspended from the middle by the bellows 23 can be used to actuate one or more pushers P, to control the functions of a chronograph, to make a quick change of date or time zone, or to order any other function. In the same figure, a bellows S is also schematically shown for sealingly connecting the winding crown and / or time setting C to the box B.

It should be noted that the assembly modes described above are not limited by their method of manufacture to cylindrical geometries. It is possible to realize complex geometries combining curves and lines with great freedom, as in the embodiment illustrated by the figures 4 and 4a .

The figure 5 illustrates a bellows 23 incorporated between the middle part 24 and the glass 21, under the bezel 28, with a stamp or a gong 25 and a deflection element 26 of the patch or gong towards the ice 21 and a bearing element 29 against the ice 21. In this assembly, the attachment of the ice with a flexible bellows makes it possible to transmit to the outside vibrations generated inside the box (or conversely), while preserving the tightness of the box. The ice-shield assembly may advantageously be sized so that its natural frequency is at higher values that the frequency band of the transmitted signal (from 100 to 4000Hz for example); this one does not find it thus degraded nor modified (distortion). The geometry of the bellows does not in any way harm the aesthetics of the room and can be integrated easily. The thickness of the wall of the bellows is of the order of 50 microns, which guarantees a sufficient lateral robustness. As illustrated in figure 2 , protections are nevertheless provided by the presence of vertical stops b1 and b2 or side b3 to prevent damage to the system during very strong external stresses.

The figure 6 Referring to a variant in which an annular bellows 33 is disposed between the bottom 40, to which it is fixed by welding, and the middle part 34. The other end of the bellows is clamped between two rings 35, 36 tightened against each other. the other by a ring 37 fixed to the middle part 34 by screws 38. A compression seal J seals the system.

We will now examine how the elastic metal member 3, 23, 33 in the form of a ring of recessed straight section defined by the profile of a non-rectilinear wall of constant thickness, constituting a bellows when it comprises at least two adjacent folds forming a meander ( figure 7 ). Our goal is to be able to obtain a self-guided metal organ, ie not susceptible to flaming or deforming, integrable to a watch box and which has a stiffness adapted to the desired function.

• Raideur en fonction de l'épaisseur de paroi e
• Raideur en fonction de la largeur a d'un méandre
• Raideur en fonction de la dimension du pas p

For the sake of simplification, the descriptions of the stiffnesses are made initially for a single meander, corresponding to n = 1. The following parameters are therefore considered separately:

• Stiffness according to wall thickness e
• Stiffness according to the width a of a meander
• Stiffness depending on the size of the pitch p

Horizontale k_h ∝ e ^3/2

The stiffnesses are defined by k , their index gives the vertical direction v , horizontal h or tilting b . Stiffness according to e according to a according to p Vertical and tilting k _v α k _b α e ³

horizontal k _h α e ^3/2

Taking into account the dependencies expressed in the table above, one can seek to maximize the ratio ^kh / _kv to facilitate and guarantee autoguiding while having k _v fixed. This ratio is a function of e ^-1.5 , at ^1.5 and p ^-0.2 . Thus, for a vertical stiffness value set by the physical data of the studied system, it is possible to determine a suitable thickness range. Knowing that a is necessarily greater than e , we must seek to minimize p within the limits of machining techniques. In addition, it must be ensured that the strength limits of the material are not exceeded. For clarity in these explanations, a numerical example and appropriate bounds are given in the following description.

Horizontale $k_h\propto \frac{1}{n^3}$

pour n grand $k_h\propto \frac{1}{n^2}$

pour n petit It is interesting to discuss beforehand the influence of the number n of meanders which is expressed according to the following relations: Stiffness according to n Vertical and tilting

horizontal ${\mathrm{<figure-callout\; id="1"\; label="k\; h\; \alpha "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">k\; </figure-callout>}}_h\alpha \frac{1}{{\mathrm{not}}^3}$

for big n ${\mathrm{<figure-callout\; id="1"\; label="k\; h\; \alpha "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">k\; </figure-callout>}}_h\alpha \frac{1}{{\mathrm{not}}^2}$

for n small

We must add a dependency in n ^-1 (for n small) in the ratio ^kh / _kv described above. If we want to maximize it, it is therefore implicit to have n the smallest. Knowing that n can only take integer or half-integer values, n = 0.5 would correspond to an ideal solution, but in the embodiments envisaged n = 1 is preferable. Moreover, as mentioned above, it is also necessary to take into account the strength limits of the materials in such a system, which is favored by increasing the value of n between 0.5 and 5, ie between 1 and 10 annular folds. alternated.

In summary, guaranteeing the autoguiding of the system is equivalent to minimizing n and p for values of e and a linked to a stiffness defined by the physical function of the bellows.

Here we want to illustrate and supplement the previous comments with two numerical examples, which can be found in the following table: Parameter Mini terminal Example 1 Example 2 Max terminal Typical stiffness 50 N / mm 500 N / mm e 10 μm 35 μm 50 μm 200 μm at 0.1 mm 1 mm 0.8 mm 4 mm p > 80 μm 0.9 mm 0.8 mm 5 mm not 0.5 3 1 ~5

• L'épaisseur e est bornée de la façon suivante :
  • La borne inférieure correspond à la limite de la technique de fabrication. De plus, la stabilité mécanique du soufflet doit être garantie, ce qui est typiquement le cas à partir de 10 µm environ.
  • La borne supérieure correspond à un temps de dépôt et à un coût raisonnables.
• La largeur a est bornée de la façon suivante :
  • La borne inférieure est en lien avec la borne inférieure de e. Au sens strictement géométrique, il faut a > 10. e pour garantir une épaisseur constante lors du dépôt.
  • La borne supérieure est également en lien avec la borne supérieure de e mais aussi en lien avec les contraintes géométriques d'une pièce horlogère. On ne peut pas raisonnablement envisager un soufflet avec a > 4mm sur un diamètre global typique de 30 mm.
• La hauteur p est bornée de la façon suivante :
  • La borne inférieure est en lien avec les contraintes mécaniques qui exigent un rayon de courbure du méandre au moins 4 fois supérieur à e.
  • La borne supérieure est définie par la hauteur maximale admissible pour une intégration dans une pièce horlogère (avec n = 1).

These examples make it possible to define maximum and minimum limits for these various parameters as a function of the different possible uses of the closure element of the opening or openings of the middle part of the watch case object of the invention:

• The thickness e is bounded as follows:
  • The lower limit corresponds to the limit of the manufacturing technique. In addition, the mechanical stability of the bellows must be guaranteed, which is typically the case from about 10 microns.
  • The upper limit corresponds to a deposit time and a reasonable cost.
• The width a is bounded as follows:
  • The lower bound is in connection with the lower bound of e . In the strictly geometrical sense, it is necessary to have a > 10. e to guarantee a constant thickness during the deposit.
  • The upper limit is also related to the upper limit of e but also in relation to the geometric constraints of a watch. It is not reasonable to envisage a bellows with a > 4mm on a typical overall diameter of 30mm.
• The height p is bounded as follows:
  • The lower bound is related to mechanical stresses that require a meander radius of curvature at least 4 times greater than e .
  • The upper limit is defined by the maximum height allowed for integration into a watch piece (with n = 1).

• La borne inférieure géométrique est implicite.
• La borne supérieure doit garantir un autoguidage sans flambage du soufflet et ce pour un diamètre global du soufflet de l'ordre de 30mm.

Finally n is bounded as follows:

• The geometric lower bound is implicit.
• The upper limit must guarantee a homoguide without buckling of the bellows and this for an overall diameter of the bellows of the order of 30mm.

• Un système glace-lunette mobile et basculant avec une amplitude de déplacement vertical de l'ordre du millimètre pour une activation de fonctions (exemple 1, schématisé dans la figure 3).
• Un système glace-lunette mobile avec une amplitude de déplacement vertical de l'ordre de la dizaine de microns pour une utilisation en tant que haut-parleur (exemple 2, mode de réalisation illustré dans la figure 5).

The two examples described in the table thus give two possibilities of realization which allow a watchmaking integration of a metal bellows with autoguiding for two types of possible applications:

• A movable and tilting ice-telescope system with a vertical displacement amplitude of the order of one millimeter for activation of functions (example 1, schematized in FIG. figure 3 ).
• A mobile ice-telescope system with a vertical displacement amplitude of the order of ten microns for use as a loudspeaker (example 2, embodiment illustrated in FIG. figure 5 ).

Claims (12)

1. A watch case comprising a middle (2, 24, 34) at least one opening of which is closed by a bezel (8, 5, 18, 28) and/or a crystal (1, 11, 21), or by a back (40), and in which at least one of the elements for closing the opening is linked to the middle by a resilient metal member (3, 23, 33) in the form of a ring or an endless frame and having a recessed cross section defined by the profile of a non-rectilinear wall whose ends (3a, 3b) are attached to the periphery of said closing element (1, 11, 21, 18), respectively of the middle (2, 24, 34), the profile of said non-rectilinear wall forming at least one annular fold having an orientation parallel to the plane of said opening, said resilient metal member (3, 23, 33) forming a bellows comprising at least said annular fold formed by a curvature, the arc of which describes an angle of between >90° and 180°, to give said closing element (1, 11, 21, 18) a freedom of movement relative to the plane of the opening, able to a movement in a direction perpendicular to the opening.
2. The watch case as claimed in the previous claim, characterized in that it comprises a mobile bezelcrystal system, and in that the resilient metal member comprises at least two adjacent folds comprising a vertical stiffness suited to a vertical displacement amplitude of the order of a millimeter for activation of functions or with a vertical displacement amplitude of the order of ten or so microns for use as a loudspeaker.
3. The watch case as claimed in one of previous claims, in which the profile of the wall of said resilient metal member (3, 23, 33) includes a plurality of alternate annular folds, the number of which is between 2 and 10, formed around respective planes parallel to the plane of said opening.
4. The watch case as claimed in one of the preceding claims, in which the thickness e of said wall is between 10 µm and 200 µm, the width a of the annular fold is between 0.2 mm and 4 mm, the pitch p of the annular fold being between >40 µm and 2.5 mm, to give said closing element a freedom of movement with controlled stiffness and orientation relative to the plane of the opening.
5. The watch case as claimed in one of the preceding claims, in which said ends (3a, 3b) of the profile of the wall of said resilient metal member (3, 23, 33) are linked in a seal-tight manner to the periphery of said closing element (1, 11, 21, 18), respectively of the middle (2, 24, 34).
6. The watch case as claimed in claim 5, in which seals (4, 6) are fitted between the respective cylindrical ends (3a, 3b) of the wall of said resilient metal member (3, 23, 33) adjacent to cylindrical seats of said closing element (1, 11, 21, 18), respectively of said middle (2, 24, 34) and compression rings or frames (5, 7) in order to ensure the seal-tightness of said case.
7. The watch case as claimed in one of the preceding claims, in which said resilient metal member (3, 23, 33) is at least partly made of one of the following metals or alloys: Ni+cobalt 99.8% with 0.04% sulfur, Ni with no more than 0.02% sulfur, bronze, copper, gold, silver or tin.
8. The watch case as claimed in one of the preceding claims, in which said resilient metal member (3, 23, 33) is coated with poly-p-xylylene.
9. The watch case as claimed in one of the preceding claims, in which said resilient metal member (3, 23, 33) is coated with zinc, gold, silver and/or titanium.
10. The watch case as claimed in one of the preceding claims, in which the thickness of the wall of said resilient metal member (3, 23, 33) is constant.
11. The watch case as claimed in one of the preceding claims, in which the ends (3a, 3b) of said metal member are joined by gluing, solderbrazing, electronic bombardment or by laser.
12. The watch case as claimed in one of the preceding claims, in which vertical and/or lateral abutments are arranged to limit the displacement of said closing element.

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