CH716164A2 - Waterproof watch box. - Google Patents

Abstract

The waterproof watch case (1) of a watch, in particular a diving watch, comprises at least one case back (4) mounted on a lower side of a caseband (2), and a crystal ( 3) mounted by means of a seal (5, 5 ') for fixing on an upper side of the caseband. The base comprises an annular bearing surface (24) for coming into contact with an annular inner surface (32) of the middle part of a shape complementary to the bearing surface when the base is mounted on the middle part. The annular bearing surface (24) and the annular inner surface (32) are inclined towards the inside of the watch case (1) by a determined angle smaller than 90 ° with respect to a central axis perpendicular to a watch case plane so as to distribute the stresses between the back and the caseband due to the water pressure during a dive. The annular bearing surface and the annular inner surface may be of conical shape. According to particular embodiments, the crystal (3) also comprises an annular peripheral surface (13) inclined for mounting on an annular inner surface (12) of complementary shape on the upper side of the middle part (2) by means of a seal (5, 5 ').

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 watertight watch case are defined in dependent claims 2 to 16.

[0009] An advantage of the waterproof watch case lies in the fact that an annular bearing surface of the bottom inclined towards the inside of the watch case comes into contact with an annular inner surface of the middle part of complementary shape to the annular bearing surface when mounting the caseback on the middle part. The bearing and interior surfaces are inclined towards the interior of the watch case by a determined angle smaller than 90 ° with respect to a central axis perpendicular to a plane of the watch case. In the case of a caseband of generally cylindrical shape, the bearing and inner surfaces are of conical shape. This makes it possible to have a good distribution of the stresses between the back and the caseband due to the pressure of the water when diving at great depths underwater.

An advantage of the waterproof 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. In this way, pressure forces on the crystal are transmitted to the caseband via conical bearing surfaces.

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: FIGS. 1a and 1b represent in a simplified manner a cross section of a first variant of a watch with a waterproof case according to the invention, and a partial detail section of the attachment of the crystal to the caseband of the first variant according to the invention, and FIGS. 2a and 2b represent in a simplified manner a cross section of a second variant of a watch with a waterproof case according to the invention, and a partial detail section of the attachment of the crystal to the caseband of the second variant 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 a first variant 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 a back 4 mounted on a lower side of the caseband 2. A bezel 7 can still be mounted on the upper side of the middle part 2. A movement or watchmaking 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. rest position on or through the middle 2 for setting the time, date or other functions of the diving watch.

According to the first variant, the bottom 4 comprises a fixing means, such as an annular edge 14 to be mounted on the lower side of the middle part 2. An annular bearing surface 24 of the bottom 4 comes into contact with 'an annular inner surface 32 of the middle part 2 of complementary shape to the bearing surface 24 when mounting the bottom 4 on the middle part 2. The 24 and inner 32 bearing surfaces are inclined towards the inside of the case. watch 1 at a determined angle smaller than 90 ° with respect to a central axis perpendicular to a plane of watch case 1.

In the case of a caseband 2 of generally cylindrical shape, the surfaces 24, 32 are of conical shape and inclined towards the inside of the watch case 1 by a determined angle smaller than 90 ° with respect to a central axis of the watch case 1. This means that the top of each cone shape is towards the interior of the watch case 1. The lower side of the caseband 2 further includes an annular groove 16 housing a gasket O-ring seal 6 (Butadiene Nitrile Rubber) in contact with the bearing surface 24 of the back 4 when mounting the back 4 on the caseband 2. Preferably, the annular edge 14 of the back 4 comprises an internal thread for be screwed onto a thread 26 on the lower side of the case 2. For a case 2 and a solid back 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 solid bottom 4 and the middle part 2 due to the pressure of the water during diving at great depths underwater.

It should be noted that the bottom 4 can also be made of sapphire or mineral glass such as crystal 3 to have a skeletal watch case structure 1 in order to view the inside of the diver's watch.

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

If the caseband 2 is generally cylindrical in shape, the peripheral inner surface 13 and the annular inner surface 12 are conical in shape and inclined at a defined angle 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 due to the pressure of the water during 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 first variant, the fixing gasket 5, 5 'can preferably be composed of a first part 5 of amorphous metal or metallic glass or amorphous metal alloy and of a second part 5' made of polymer (by example in polyurethane) for the retention of the crystal 3. The fixing gasket 5, 5 'is of annular shape 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 conical in shape, while the second part 5 'is linked to the upper edge of the first part 5 and is cylindrical. Once the crystal 3 is attached to the caseband 2, the first part 5 connects the inclined surfaces of the caseband 2 and of the crystal 3, while the second part 5 'is attached to an annular inner wall 22 of the caseband 2 and an annular outer wall 23 of the lens 3 above the annular peripheral surface 13 of the lens 3. Preferably, the second part 5 'stops at mid-height of the lens 3 just below the bezel 7 , while the first part 5 of the seal extends below the level of the connection between the bottom of the crystal 3 and the caseband 2.

[0020] 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.

Normally if the seal 5, 5 'of annular fixing is made before the fixing of the crystal 3 on the middle part 2, it is mainly the second part 5' of the seal which is used to hold the glass 3 to the middle part 2, while the first part 5 of the seal is of the type carrying the crystal 3 on the middle part 2. However, it can also be imagined to have the two parts separated so as to allow the first part 5 to be hot-set to the caseband 2 and the crystal 3 before making the second part 5 'of the seal on the first part 5 to retain the crystal 3 by the annular outer wall 23 to the inner wall 22 of the caseband 2, which also guarantees a good sealing.

When the watch case 1 is submerged under water to great depths, this makes it possible to close any space between the crystal 3 and the middle part 2 thanks to the inclined surfaces 12 and 13 of the glass 3 and the middle part 2 and through 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 made of amorphous metal or amorphous metal alloy.

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 'inward 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 metal part 5 of the seal. In the most frequent cases, the amorphous metal alloy can be mainly composed of zirconium, which makes it possible to form the seal at a temperature above 350 °, that is to say above the glass transition temperature of the 'alloy. The amorphous zirconium metal alloy can be composed of Zr (52.5%), Cu (17.6%), Ni (14.9%), Al (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 amorphous metal alloy based on zirconium 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%). Preferably, to facilitate the production of such a seal, the amorphous metal alloy can be mainly composed of platinum (Pt), which makes it possible to form the seal at a temperature above 230 ° C. The platinum-based amorphous metal alloy can include Pt (57.5%), Cu (14.7%), Ni (5.3%) and P (22.5%). Provision may also be made to produce the one-piece metal seal 5, 5 'from an amorphous metal alloy based mainly on palladium (Pd), which makes it possible to form the seal at a temperature above 300 ° C.

Mention may still be made of other alloys of amorphous metals. 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%). An amorphous nickel-based 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%).

Figures 2a and 2b show a second variant of a watch case 1, which can be used for a diving watch. As most of the elements of this second variant are identical to the first variant explained with reference to FIGS. 1a and 1b, they will not be repeated. The differences are on the one hand at the level of the back fixing means 4 on the lower side of the caseband 2 and at the level of the metal seal 5, 5 'for fixing the crystal 3 to the caseband 2.

The solid bottom 4 is fixed to the middle part 2 by means of a ring 4 'as a fastening means. This ring 4 'is provided with an inner bearing surface coming into contact with a peripheral outer surface of the bottom 4, which is preferably of complementary shape. The inner bearing surface of the ring 4 'is curved or inclined towards the center of the base 4. The ring 4' further comprises an annular edge 14 having an internal thread to be screwed onto a thread 26 on the lower side of the caseband. 2 when mounting the back 4, resting on the inner bearing surface of the ring 4 ', on the middle part 2. The ring 4 can be of the same material as the back 4 or of another metallic material.

In the case of a middle part of generally cylindrical shape, the seal 5, 5 'for fixing the annular shape is made entirely of amorphous metal or metallic glass or amorphous metal alloy. It comprises a first part 5 of the conically shaped seal, and a second cylindrical part 5 'linked to the upper edge of the first part 5 to form a single piece. The general shape of the fixing joint 5, 5 'is identical to that of FIGS. 1a and 1b, and the same is true for the angle of inclination of the surfaces 12, 13. Preferably, the glass 3 is fixed hot. to the caseband 2 by the gasket 5, 5 'in amorphous metal.

For information, the production of such a gasket 5, 5 'in amorphous metal can be made by different shaping processes, either: directly from molten metal such as for example pressure injection, gravitational casting, centrifugal casting, anti-gravity casting, suction casting, powder additive manufacturing from amorphous preforms 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 to allow its deformation during the assembly step described below.

It should also be noted that with the fixing of the crystal 3 on the caseband 2 of the embodiments described above and with the contact of conical surfaces between the crystal 3 and the caseband 2, it is guaranteed a good tightness and good distribution of stresses between crystal 3 and caseband 2. The same applies to the contact of the conical surfaces of caseback 4 and caseband 2. This is necessary given that the watch is a diving watch which must withstand strong stresses due to the pressure difference between the inside of the watch and the water pressure at great depths underwater. As the contact surfaces between the middle 2, the seal 5, 5 'and the crystal 3, or between the middle 2 and the back 4 are quite large with these conical shapes, there is a better transmission of the stresses over a larger area. This is important to ensure the water resistance of the watch when diving deep underwater. With these arrangements, the pressure of the water on the watch case 1 tends to close any gap between the contact surfaces. In addition, this prevents the extrusion of the fixing gasket 5, 5 '.

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 (16)

1. Watertight watch case (1), in particular for a diving watch, the case (1) comprising at least one case back (4) mounted on a lower side of a caseband (2), and a crystal (3) mounted on an upper side of the caseband (2), characterized in that the base (4) comprises an annular bearing surface (24) to come into contact with an annular inner surface (32) of the middle part (2) of complementary shape to the bearing surface (24) when mounting the back (4) on the case (2), and in that the annular bearing surface (24) and the annular inner surface (32) are inclined towards the inside of the watch case (1) by a determined angle smaller than 90 ° with respect to a central axis perpendicular to a watch case plane (1) so as to distribute stresses between the back (4) and the middle (2) due to the pressure of the water during a dive. 2. Watch case (1) according to claim 1, characterized in that the annular bearing surface (24) of the base (4) and the annular inner surface (32) of the middle part (2) are of conical shape. 3. Watch case (1) according to one of claims 1 and 2, characterized in that the determined angle of inclination of the bearing surfaces (24) and interior (32) is of the order of 60 ° ± 5 ° from the central axis. 4. Watch case (1) according to one of claims 1 and 2, characterized in that the lower side of the middle part (2) further comprises an annular groove (16) housing a sealing gasket (6) in contact. of the bearing surface (24) when mounting the back (4) on the caseband (2). 5. Watch case (1) according to claim 4, characterized in that the bottom (4) comprises an annular edge (14) having an internal thread to be screwed onto a thread (26) on the lower side of the caseband ( 2) when mounting the back (4) on the middle (2). 6. Watch case (1) according to claim 4, characterized in that a ring (4 ') is provided for mounting the bottom (4) to the caseband (2), in that the ring (4') is provided with an inner bearing surface coming into contact with a peripheral outer surface of the bottom (4), which is of complementary shape, and in that the ring (4 ') comprises an annular edge (14) having a internal thread to be screwed onto a thread (26) on the lower side of the caseband (2). 7. Watch case (1) according to claim 1, characterized in that the crystal (3) comprises an annular peripheral surface (13) to be mounted by means of at least part of a seal (5, 5 ') for fixing to an annular inner surface (12) of complementary shape on the upper side of the middle part (2), and in that the annular peripheral surface (13) of the crystal (3) is inclined towards the inside of the watch case (1) at an angle defined smaller than 90 ° with respect to a central axis perpendicular to a watch case plane so as to distribute the stresses between the crystal (3) and the caseband (2) due to water pressure during a dive. 8. Watch case (1) according to claim 7, characterized in that the part of the seal (5, 5 ') for fixing between the annular peripheral surface (13) and the annular inner surface (12) is made of amorphous metal or made of amorphous metal alloy. 9. Watch case (1) according to one of claims 7 and 8, characterized in that the fixing gasket (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) at the above the annular inner surface (12) and an annular outer wall (23) of the glass (3) above the annular peripheral surface (13). 10. Watch case (1) according to claim 9, characterized in that the annular walls (22, 23) are parallel to the central axis. 11. Watch case (1) according to claim 9, characterized in that the first part (5) of the fixing gasket is made of amorphous metal or an amorphous metal alloy, and in that the second part (5 ') of the gasket fixing is in polyurethane to fix the crystal (3) to the middle part (2). 12. Watch case (1) according to one of claims 8 and 11, characterized in that the amorphous metal alloy of at least part of the seal (5, 5 ') for fixing is based mainly on zirconium. 13. Watch case (1) according to one of claims 8 and 11, characterized in that the amorphous metal alloy of at least part of the seal (5, 5 ') for fixing is based mainly on platinum. 14. Watch case (1) according to one of claims 8 and 11, characterized in that the amorphous metal alloy of at least part of the seal (5, 5 ') for fixing is based mainly on palladium. 15. Watch case (1) according to claim 9, 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. 16. Watch case (1) according to claim 15, 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.