CH716165A2 - Waterproof watch box. - Google Patents

Abstract

The watertight watch case (1) of a watch, in particular a diving watch, comprises a crystal (3) mounted on an upper side of the middle part (2). The lens comprises an annular peripheral surface (13) mounted by a first part (5) of an annular seal, for example of amorphous metal, on an annular interior surface (12), preferably of complementary shape, on the upper side of the glass. build. A second part (5 ') of the seal above the first part of the seal optionally holds the crystal to the caseband. According to the invention, the annular peripheral surface (13) of the crystal (3) is inclined towards the inside of the watch case (1) at an angle smaller than 90 ° with respect to a central axis perpendicular to the plane watch case (1) to distribute stresses between the crystal (3) and the middle (2) due to the water pressure during a dive. The annular peripheral surface and the annular inner surface are preferably conical in shape.

Description

TECHNICAL AREA

The present invention relates to a waterproof watch case in particular for a diving watch.

TECHNOLOGICAL BACKGROUND

[0002] To provide for the use of a mechanical or electronic watch under water, the watch case, which comprises a watch movement or a time-based watch module, must be closed in a well-sealed manner. To do this, the watch case comprises a case back fixed in a sealed manner to a first side of a middle part and a crystal fixed to a second opposite side of the middle part. Sealing gaskets are provided for the assembly of the back, the caseband and the watch crystal. A member for controlling or adjusting the functions of the watch is also mounted in a sealed manner through the middle part of the case in the rest position.

[0003] Generally, watch cases are not configured or assembled to withstand high water pressures, for example during diving, given that the pressure inside the watch case is close to atmospheric pressure. Simple gaskets of traditional watches are not sufficient to guarantee a good watertightness of the case when diving to very great depths underwater.

Mention may be made of patent application CH 690 870 A5 which describes a waterproof watch case. The watch case consists of a crystal fixed on an upper side to a caseband-bezel and a caseback fixed to the caseband by screwing it to an internal thread of the caseband. The crystal is fixed to the middle part by an annular seal in the shape of a toric and rests on a middle edge. A seal is also provided between an outer edge of the back and a lower surface of the caseband. As at high water pressure the thread can be damaged, a strong metal cup is still provided to bear against an interior surface of the back and against an interior edge of the caseband. However, even with such a watch case arrangement, this does not make it possible to guarantee good sealing of the case during diving to very great depths underwater, which constitutes a drawback.

[0005] Patent CH 372 606 describes a waterproof watch case which has a central part or middle part surrounding a back and closed by a crystal. A threaded ring bears against an inclined outer surface of the caseback to retain it, and is screwed to a fastening portion connected to the caseband. With such an arrangement presented, this does not make it possible to guarantee good sealing of the box during diving to very great depths underwater, which constitutes a drawback.

SUMMARY OF THE INVENTION

[0006] The main aim of the invention is therefore to overcome the drawbacks of the state of the art described above by providing a watertight watch case adapted to withstand high water pressure for diving at great depths underwater.

[0007] To this end, the present invention relates to a waterproof watch case, which comprises the features of independent claim 1.

[0008] Particular embodiments of a waterproof watch case are defined in dependent claims 2 to 15.

[0009] An advantage of the watertight watch case lies in the fact that the crystal is fixed to the middle part by means of a seal and with inclined contact surfaces of the middle part and the crystal. In the case of a middle part of generally cylindrical shape, conical bearing surfaces are provided on the crystal and the middle part, or even on the back mounted on an opposite side of the middle part. In this way, pressure forces on the crystal and the back are transmitted to the caseband via conical bearing surfaces.

[0010] In the case of ice, its behavior as well as the tightness of its connection to the middle part can be ensured by a second part of the fixing gasket made of polymer (for example polyurethane). The pressure forces are transmitted to a first part of the seal which is made of a metal having mechanical properties superior to those of the middle part, in particular an upper elastic limit and ideally a higher elastic deformation. It may be a gasket made of amorphous metal alloy or of TNTZ-O alloy (TiNb23Ta0.7Zr2O1.2) for a titanium middle part. This makes it possible to avoid stress concentrations on the one hand on the middle part and thus avoid its plasticization and on the other hand on the crystal and thus prevent its breaking and / or reduce its thickness. The first part of the metal seal may be a component which is placed on the conical support of the caseband before the lens is fitted. The first part of the seal may also have been secured to the middle part in a preliminary step (eg by hot forming or additive manufacturing) and therefore be an integral part of the middle part when the lens is fitted.

BRIEF DESCRIPTION OF THE FIGURES

The aims, advantages and characteristics of a waterproof watch case will appear better in the following description in a non-limiting manner with regard to the drawings in which: Figures 1a and 1b schematically show a cross section of an embodiment of a watch with a waterproof case according to the invention, and a partial detail section of the attachment of the crystal to the middle part according to the invention, FIG. 2 represents a partial detail section of a variant of the attachment of the crystal to the middle part according to the invention, FIG. 3 diagrammatically represents a top view of an embodiment of a watch case according to the invention, and FIGS. 4a and 4b represent a crystal with a metallic coating capable of being engraved by a laser for the production of an inscription on the mounting surface of the crystal on the caseband, and a portion of the metallic coating on the crystal with the inscription according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, all the components of a watertight watch case, in particular a diving watch, which are well known to a person skilled in the art in this technical field are only described in a manner simplified.

Figures 1a and 1b show an embodiment of a watch case 1, which can be used for a diving watch. The watch case 1 essentially comprises a crystal 3, which can be made of sapphire or mineral glass, fixed on an upper side of a caseband 2, and possibly a back 4 mounted on a lower side of the caseband 2. A bezel 7 can also be mounted on the upper side of the middle part 2. A movement or watch module 10 is arranged in the watch case 1 in a casing circle 8, and at least one control member, not shown, can be mounted in a sealed manner in the rest position on or through the middle 2 for setting the time, date or other functions of the diving watch.

In the case where there is provided a bottom 4 of the watch case 1, the bottom 4, which is preferably of solid structure, comprises an annular edge 14 with internal thread to be screwed onto a thread 26 on the side lower part of the case 2. An annular bearing surface 24 of the back 4 comes into contact with an annular inner surface 32 of the case 2 of a shape complementary to the bearing surface 24 when mounting the back 4 on the case 2 The bearing surfaces 24 and inner 32 are inclined at a determined angle with respect to an axis perpendicular to a watchcase plane 1. In the case of a middle part of generally cylindrical shape, the surfaces 24, 32 are of conical shape and inclined towards the inside of the watch case 1 at a determined angle with respect to a central axis of the watch case 1. This means that the apex of each cone shape is towards the inside of watch case 1. The lower side of caseband 2 still includes a ra annular inure 16 housing a sealing gasket 6 in contact with the bearing surface 24 during the mounting of the back 4 on the middle part 2. The annular groove 16 has a rectangular cross section so that the sealing gasket 6 is well maintained in the annular groove 16 before fixing the back 4. For a caseband 2 and a caseback 4 made of a material, such as titanium, the angle may be of the order of 60 ° ± 5 ° relative to the central axis. This makes it possible to have a good distribution of the stresses between the bottom 4 and the middle 2 due to the pressure of the water during diving at great depths underwater.

The crystal 3 comprises an annular peripheral surface 13 to be mounted by means of at least part of a seal 5, 5 'on an annular inner surface 12 on the upper side of the middle part 2. The inner surface annular 12 is preferably of complementary shape to the annular peripheral surface 13. The annular peripheral surface 13 of the crystal 3 is inclined at a defined angle smaller than 90 ° relative to an axis perpendicular to a plane of the watch case 1 Preferably, the annular interior surface 12 is inclined generally towards the interior of the watch case 1 at the same angle as the annular peripheral surface 13 with respect to a central axis.

If the middle part 2, for example made of titanium, is of generally cylindrical shape, the peripheral inner surface 13 and the annular inner surface 12 are of conical shape and inclined at an angle defined towards the inside of the watch case . This means that the apex of each cone shape is towards the inside of the watch case 1. The defined angle of inclination of surfaces 12 and 13 can be of the order of 43 ° ± 5 ° from to the central axis. This makes it possible to have a good distribution of the stresses between the crystal 3 and the caseband 2 by means of the first part 5 of the seal due to the pressure of the water when diving at great depths underwater. . The difference in water pressure relative to the pressure inside the watch case 1 tends to close any gap between the surfaces 12, 13 in contact and the seal 5, 5 ′ for fixing thanks to the inclination of the contact surfaces towards the inside of the watch case 1. This guarantees a good seal and resistance to high pressures.

In this embodiment, the fixing gasket 5, 5 'can preferably be composed of a first part 5 of amorphous metal alloy and of a second part 5' made of polymer (for example polyurethane) for the retention of the crystal 3 to the caseband 2. The fixing gasket 5, 5 'is annular for the hermetic closure of the crystal 3 on the caseband 2. For a caseband 2 of generally cylindrical shape, the first part 5 of the seal is of conical shape, while the second part 5 'bears on the upper edge of the first part 5 and is cylindrical. Once the crystal 3 has been driven out of the middle part 2, the first part 5 connects the inclined surfaces of the middle part 2 and the crystal 3 resting on the first part 5, while the second part 5 'is compressed between the annular inner wall 22 of the caseband 2 and the annular outer wall 23 of the crystal 3 above the annular peripheral surface 13 of the crystal 3. The second part 5 'can stop at mid-height of the crystal 3 just below the bezel 7, while the first part 5 of the seal may extend below the level of the connection between the bottom of the crystal 3 and the middle 2.

Without limitation, the length of the first part 5 in cross section can be of the order of 5 mm, while the height of the second part of the seal 5, 5 'can be of the order of 2.5 mm. The thickness of the seal can be of the order of 0.65 mm.

The first part 5 of the seal is of the type carrying the glass 3 on the caseband 2. When the watch case 1 is submerged under water to great depths, this makes it possible to close any space between the glass 3 and the caseband 2 thanks to the inclined surfaces 12 and 13 of the crystal 3 and the caseband 2 and via the first metal part 5 of the seal. A good distribution of the stresses is therefore achieved between the crystal 3 and the caseband 2 thanks to the first metal part 5 of the seal, which is preferably made of an amorphous metal alloy.

When the watch case 1 is submerged under water to shallow depths, the part 5 'of the seal makes it possible to ensure the tightness and the holding of the crystal on the caseband. The more the case is submerged under water to great depths, the more the glass is compressed against part 5 of the seal which itself is compressed against the inclined plane of the caseband which makes it possible to ensure tightness even at high temperatures. very great depths without the risk of damaging the seal. At great depths, part 5 'of the seal comes to rest against the top of part 5 of the seal, which prevents part 5' from being degraded by extrusion. The use of a material having very high mechanical properties (in particular the elastic limit and the elastic deformation) for part 5 of the gasket is necessary to avoid its plasticization and to ensure a homogenization of the stresses on the middle part during the plunging of the shows at great depths.

For example, the particular mechanical properties of amorphous metals, in particular their elastic limit σetrès high (eg: 1700 MPa for a Zr base; 1550 MPa for a Pd base; 1350 MPa for a Pt base) coupled to a deformation elastic εetrès high (1.5 to 2% for all amorphous metals), make it possible to avoid plasticization of the seal 5, 5 ′ in its zone of contact with the lens 3 during a stress at very high pressures. Case 2, whose mechanical properties (e.g. for grade 5 titanium: σe850 MPa; εe0.5 to 0.8%) are lower than the amorphous metals chosen for the seal, does not plasticize either because the seal 5, 5 'in amorphous metal makes it possible to homogenize the stresses, which then decrease at the joint - middle part interface.

Another example of an interesting alloy for the manufacture of the seal 5 is an alloy of TNTZ-O type (TiNb23Ta0.7Zr2O1.2) which has an elastic limit of 1'000-2'000 MPa with an elastic deformation of around 1-2%.

For information, the realization of the first part 5 of the amorphous metal gasket can be done by different shaping processes, either: <tb> <SEP> - directly from molten metal such as for example pressure injection, gravitational casting, centrifugal casting, anti-gravity casting, suction casting, powder additive manufacturing, <tb> <SEP> - from preforms amorphous by hot deformation above the glass transition temperature such as, for example, electromagnetic forming, forming by capacitive discharge, forming under gas pressure, mechanical forming. The objective of this step is to obtain a preform having the right dimensions and having a sufficient proportion of amorphous phase for the mechanical properties to be adapted.

It should also be noted that the annular inner surface 12 of the middle part 2 is inclined towards the inside of the watch case 1 and ends with a curved surface 12 'inwardly over approximately 3 ° following of the annular interior surface 12. Thus the first part 5 of the seal is no longer in direct contact with this curved surface 12 '. On the other hand, when the water pressure increases substantially when diving, the first part 5 of the seal is pushed by the glass 3 inwards to contact or conform to the curved surface 12 '. This thus makes it possible to prevent the pressure from the inside corner of the glass 3 concentrating the stresses in the first part 5 of the seal, risking breaking it.

Several types of amorphous metal alloys can be used to make the first part 5 of the fixing joint. In the most frequent cases, the amorphous metal alloy can be mainly composed of zirconium. The amorphous metal alloy based on zirconium can be composed of Zr (52.5%), Cu (17.6%), Ni (14.9%) , AI (10%) and Ti (5%). The amorphous metal alloy based on zirconium can also include Zr (58.5%), Cu (15.6%), Ni (12.8%), Al (10.3%) and Nb (2.8%). The zirconium-based amorphous metal alloy can also include Zr (44%), Ti (11%), Cu (9.8%), Ni (10.2%) and Be (25%), or finally Zr (58%) , Cu (22%), Fe (8%) and Al (12%). It is also possible to make the first part of the seal in an amorphous metal alloy mainly composed of platinum (Pt). The amorphous metal alloy based on platinum can include Pt (57.5%), Cu (14.7%), Ni (5.3 %) and P (22.5%). Provision may also be made for the first part of the seal to be made from an amorphous metal alloy based mainly on palladium (Pd).

Mention may also be made of other amorphous metal alloys. An amorphous titanium-based metal alloy can include Ti (41.5%), Zr (10%), Cu (35%), Pd (11%) and Sn (2.5%). An amorphous metal alloy based on palladium can include Pd (43%), Cu (27%), Ni (10%) and P (20%), or Pd (77%), Cu (6%) and Si ( 16.5%), or finally Pd (79%), Cu (6%), Si (10%) and P (5%). A nickel-based amorphous metal alloy can include Ni (53%), Nb (20%), Ti (10%), Zr (8%), Co (6%) and Cu (3%), or Ni ( 67%), Cr (6%), Fe (4%), Si (7%), C (0.25%) and B (15.75%), or finally Ni (60%), Pd (20%), P (17%) and B (3%). An iron-based amorphous metal alloy can include Fe (45%), Cr (20%), Mo (14%), C (15%) and B (6%), or Fe (56%), Co ( 7%), Ni (7%), Zr (8%), Nb (2%) and B (20%). A gold-based amorphous metal alloy can include Au (49%), Ag (5%), Pd (2.3%), Cu (26.9%) and Si (16.3%).

Figure 2 shows a partial sectional detail of a variant of the attachment of the crystal 3 to the middle 2. The crystal 3 comprises an annular peripheral surface 13 to be mounted by means of a first part 5 of the seal on an annular inner surface 12 on the upper side of the middle part 2. If the middle part 2 is generally cylindrical in shape, the peripheral inner surface 13 of the crystal 3 is conical in shape, while the annular inner surface 12 of the middle part 2 is in the plane of the watch case 1 in the form of a portion of a disc. The first part 5 of the at least partially amorphous metal alloy gasket is between the peripheral inner surface 13 and the annular inner surface 12, while the second part 5 'of the polymer gasket is between the annular inner wall 22 of the middle part 2 and the annular outer wall 23 of the glass 3.

Figure 3 schematically shows a top view of an embodiment of a watch case 1. The watch case 1 comprises the middle part 2, the crystal 3, a bezel 7 and a control member 9 in the form of a stem-crown passing through the middle part 2. The stem-crown comprises a conical surface (not shown) in contact with a conical inner surface of the middle part 2 in the rest position to ensure tightness and resistance to damage. water pressure when diving. An inscription 103 of a word or of a number or of drawings is made at the connection of the annular peripheral surface 13 of the glass 3 on the first part of the fixing joint.

As shown in Figures 4a and 4b to achieve the inscription 103, it can also be expected to have a contact surface of the glass 3 structured and / or with a decorative layer deposited on its surface. This structuring and / or deposit 63 can be placed on the annular peripheral surface 13 of the crystal 3. It can also be provided to write one or more words, or numbers or patterns by etching the deposit 63 by means of a laser beam. L from a laser device 50. The deposit 63 may be of a different color from the first part of the fixing joint. Therefore after the engraving of the inscription 103 on the deposit 63, the annular peripheral surface 13 of the crystal 3 can be placed or fixed on the first part of the fixing joint, which is of a different color than the deposit 63 .

Provision can also be made to create a pattern on the contact surface of the lens 3 by selective structuring of its surface. It is possible to structure the surface for example by a laser, by a chemical process or even by a mechanical process (for example grinding, milling). Thus, once the crystal 3 is attached to the caseband 2, it is possible to read the inscription made through the crystal 3, which can also be the indication of the watch brand.

It should also be noted that with the fixing of the crystal 3 on the caseband 2 by the second part 5 'of the seal described above and with the contact of conical surfaces between the crystal 3 and the caseband 2 by the 'intermediary of the first part 5 of the seal, it is guaranteed a perfect seal and a good distribution of the stresses between the crystal 3 and the middle part 2. This is necessary given that the watch is a diving watch which must withstand high stresses due to the pressure difference between the inside of the watch and the water pressure at great depths underwater. As the contact surface between the middle 2, the seal 5, 5 'and the crystal 3 is quite large with this conical shape, there is a better transmission of stresses over a larger surface, which is important to guarantee the water resistance of the watch during a deep dive underwater. With this arrangement, the pressure of the water on the watch case tends to close any gaps between the contact surfaces. In addition, this avoids the extrusion of the fixing joint.

[0032] From the description which has just been given, several variant embodiments of the watch case can be designed by those skilled in the art without departing from the scope of the invention defined by the claims. The watch case by its middle part may have a general shape different from a cylinder.

Claims (15)

1. Watertight watch case (1), in particular for a diving watch, the case (1) comprising at least one crystal (3) mounted on an upper side of the middle part (2), characterized in that the lens (3) comprises an annular peripheral surface (13) to be mounted via at least part of an annular-shaped seal (5, 5 ') on an annular inner surface (12 ) on the upper side of the caseband (2), and in that the annular peripheral surface (13) of the crystal (3) is inclined towards the inside of the watch case (1) by a defined angle smaller than 90 ° with respect to a central axis perpendicular to a plane watch case so as to distribute the stresses between the crystal (3) and the middle (2) due to the water pressure during a dive. 2. Watch case (1) according to claim 1, characterized in that the part of the seal (5) between the annular peripheral surface (13) and the annular inner surface (12) is made of at least partially amorphous metal alloy. 3. Watch case (1) according to one of claims 1 and 2, characterized in that the annular inner surface (12) of the upper side of the middle part (2) is of complementary shape to the annular peripheral surface (13) ice. 4. Watch case (1) according to claim 3, characterized in that the seal (5, 5 ') is composed of a first part (5) disposed between the annular peripheral surface (13) of the crystal (3) and the annular inner surface (12) of the middle part (2), and of a second part (5 ') in contact between an annular inner wall (22) of the middle part (2) above the annular inner surface ( 12) and an annular outer wall (23) of the glass (3) above the annular peripheral surface (13). 5. Watch case (1) according to claim 4, characterized in that the annular walls (22, 23) are parallel to the central axis. 6. Watch case (1) according to claim 4, characterized in that the first part (5) of the fixing gasket is made of at least partially amorphous metal alloy, and in that the second part (5 ') of the fixing is in polymer to fix the crystal (3) to the caseband (2). 7. Watch case (1) according to one of claims 2 and 6, characterized in that the amorphous metal alloy of at least part of the seal (5, 5 ') is mainly based on zirconium. 8. Watch case (1) according to one of claims 2 and 6, characterized in that the amorphous metal alloy of at least part of the seal (5, 5 ') is mainly based on platinum. 9. Watch case (1) according to one of claims 2 and 6, characterized in that the amorphous metal alloy of at least part of the seal (5, 5 ') is based mainly on palladium. 10. Watch case (1) according to claim 4, characterized in that the annular peripheral surface (13) of the crystal (3) and the annular inner surface (12) of the middle part (2) are conical surfaces, and in that the annular inner wall (22) of the middle part (2) and the annular outer wall (23) of the crystal (3) are cylindrical surfaces. 11. Watch case (1) according to claim 1, characterized in that the defined angle of inclination of the annular peripheral surface (13) of the crystal (3) is of the order of 43 ° ± 5 ° per relative to the central axis. 12. Watch case (1) according to claim 4, characterized in that the defined angle of inclination of the annular peripheral surface (13) of the crystal (3) and of the annular inner surface (12) of the middle part (2) is of the order of 43 ° ± 5 ° with respect to the central axis. 13. Watch case (1) according to claim 1, characterized in that the annular peripheral surface (13) of the crystal (3) comprises a deposit (63) for laser beam engraving an inscription (103). 14. Watch case (1) according to claim 13, characterized in that the color of the deposit (63) is different from a first part (5) of the fixing joint so as to view the inscription through the crystal ( 3) from the outside of the watch case. 15. Watch case (1) according to claim 1, characterized in that the annular peripheral surface (13) of the crystal (3) comprises a structure intended to create a decoration (103).