EP3070545A1 - Watertight watch case - Google Patents

Abstract

Watertight watch case comprising two elements respectively forming a middle part (2) and a bottom (4), a seal (10) being interposed between these two elements, a first of these elements comprising a first peripheral side wall portion ( 20) which extends in height, the second member also having a second upstanding peripheral side wall portion (26) which is of complementary shape to the first wall portion lateral peripheral (20) of the first element, the first and second peripheral side wall portions (20, 26) of the first and second elements being arranged so that, in a first angular position with respect to a pivot axis called closure axis (O-O '), the first element can be dissociated from the second element and that, in a second angular position in which the first element is t rotated by a predetermined angle ()) about said closure axis (O-O ') from the first position, the first member is locked in the second member by compressing the seal (10). The bottom (4) and the middle (2) are made of a material whose hardness is at least 1000 HV.

Description

Technical field of the invention

The present invention generally relates to watch cases and more particularly to a waterproof watch case including a middle and a bottom that can be engaged and locked in the middle part by printing at the bottom a rotational movement of a given angle around a geometric axis which will be called closing axis in the following description.

Technological background of the invention

A watch case meeting this definition is already described in the document CH 338405 . In this document, the watch case comprises a middle part, a bottom and a seal interposed between the bottom and the middle part. The bottom has a peripheral flange having an inclined outer wall shaped ellipse or polygon and the middle part has an annular groove having an inclined wall of a shape corresponding to that of the wall of the bottom flange. The rim of the bottom can thus be engaged in the groove of the middle part and be locked in this groove by rotating the bottom relative to the middle part.

This box of the prior art has the disadvantage of wearing quickly. Indeed, because of the elliptical or polygonal shape of the peripheral rim of the bottom and the complementary shape of the groove of the middle part, the bottom can be locked on the middle part only according to lines of contact which extend in one direction tangent to the inclined wall of the flange or groove. This results in a tight closure of the box is no longer provided effectively, or even more assured at all, after a number of cycles of opening and closing the bottom.

To this is added the fact that, in a watch case of this type, the compression behavior of the seal is similar to that of a seal of a watch case in which the bottom is attached to the middle by screws. In such watch cases, the seal is compressed strongly in the areas where the screws are located, and very weakly between these areas, which leads to sealing problems. However, in the case of a watch case of the type described in the document CH 338405 when the bottom is tightened on the caseband, only those parts of the bottom which, thanks to the intrinsic flexibility of the bottom, come into contact with the caseband tend to penetrate into the caseband and compress the seal in these contact areas. Thus, the areas of high and low compression succeed each other along the seal, which poses sealing problems.

The document FR 1,359,524 discloses a waterproof watch case comprising an outer member and an inner member, namely a bottom and a middle part engaged one inside the other. A seal carried by one of these elements is pressed axially against a shoulder of the other. The outer member is provided with internal projections distributed around its periphery, while the inner member has external projections also distributed around its periphery and engaged on the internal projections to fix the outer and inner elements to each other. The projections of these inner and outer members are axially limited by generator surfaces perpendicular to the axis of the box, each of these surfaces forming a ramp on which a projection of one of the elements can engage to cause a displacement axial axis of the other element when the projections of the latter are engaged on said ramps. Such a watch case has the particular disadvantage of being complicated to achieve and is therefore a high cost.

A waterproof watch case designed to remedy the problems mentioned above has already been disclosed in the document CH 685526 . Such a watch case includes a bottom and a middle both made of steel. Steel is a material commonly used in the field of watchmaking, in particular because it is easy to machine because of its hardness which does not usually exceed 200 to 300 HV. In addition, steel is a solid material. Finally, the steel is ductile, which allows the bottom and the middle part to deform and their opposite surfaces to marry when the bottom is tightened on the middle part, the resulting clamping force thus being excellent. Steel, however, has some disadvantages. The designers are limited in particular in terms of shapes that can be given to the various components of the watch case as well as in terms of choice of colors.

Summary of the invention

The invention aims to overcome the disadvantages of the aforementioned prior art as well as others by providing a sealed watch case made of a material offering manufacturers a great freedom of choice of shapes and colors.

For this purpose, the subject of the invention is a sealed watch case comprising two elements respectively forming a middle and a bottom, a seal being interposed between these two elements, a first of these elements comprising a peripheral side wall portion. axially delimited and undercut, the second member also having an axially delimited peripheral sidewall portion and an undercut of complementary shape to the sidewall portion of the first member, the sidewall portions of the first and second members being arranged so that, in a first angular position with respect to a pivot axis called closure axis, the first element can be dissociated from the second element and that in a second angular position in which the first member is rotated by a predetermined angle about said closing axis from the first position, the first member is locked in the second member by compressing the liner, the watch case waterproofing characterized in that the bottom and the middle part are made of a material whose hardness is at least 1000 HV.

According to a complementary feature of the invention, the material in which the bottom and the middle are made is a ceramic.

According to a particular embodiment of the invention, the bottom and middle part are made of sintered zirconia oxide.

Thanks to these features, the present invention provides a waterproof watch case in which the bottom and the middle part are made of a material having a hardness of at least 1000 HV. Materials that meet this definition include ceramics, for example sintered zirconia. It is known that such ceramics offer great possibilities in terms of shapes and choice of colors. Nevertheless, the substitution of steel by ceramics was not without difficulty. Indeed, ceramics are extremely hard and fragile materials. The skilled person was therefore of the opinion that the very low ductility of the ceramic materials would not allow a corresponding bottom and middle made of such a material to deform sufficiently so that their facing surfaces can marry properly when the bottom is tight on the middle to ensure a sufficient resultant clamping force. On the other hand, the skilled person also feared that the thin nets whose machining is made necessary by the watch cases of the type of object of the present patent application would be too fragile and could break due to fragility. ceramic materials. All concurred thus to divert the skilled person from the choice of a hard material for the realization of the components of a waterproof watch case according to the invention. Now, to his surprise, the Applicant has found, after several attempts, that the prejudices of the person skilled in the art were unfounded and that components, bottoms and frames, for waterproof watch cases could be made of ceramic and present all the required guarantees, particularly in terms of clamping force and mechanical strength. In addition, thanks to the choice of materials of great hardness such as ceramics, designers enjoy great freedom both in terms of choice of shapes than colors.

The peripheral side wall portion of the first element comprises at least two circular arc sections each centered on a point offset from the closure axis, these two sections being connected to each other by a reentrant section for to form projections. The peripheral side wall portion of the second element comprises, for its part, at least two arcuate segments each centered on a point offset from the closure axis, these two sections being connected to each other by a section whose profile is broken and which defines a clearance depth such that it allows, in the first angular position, the passage of the projections of the first element in the clearances of the second element. Each arcuate section of the first element is associated with an arcuate section of the second element, the sections associated with each other having substantially the same radius so that, in the first angular position, each section arc of the first element is eccentric relative to the arcuate section of the second element associated with it, while in the second angular position, each arcuate section of the first element is concentric to the arcuate section of the second element associated with it. Thus, the side wall of each arcuate section of the second element is in intimate contact throughout its entire extent with the side wall of the arcuate section of the first element associated therewith.

The contact between the peripheral side wall portion of the first member and the peripheral side wall portion of the second member is therefore in a larger area. The friction forces between these two elements are therefore better distributed, which improves the reliability of the system and reduce wear. The structure of the box according to the invention also allows to obtain a progressive tightening of the first element on the second element by compressing the seal uniformly and progressively.

Preferably, the peripheral side wall portion of the first and second elements comprises four sections in an arc regularly distributed along the perimeter of the first and second elements.

Thus, the bottom is self-centering on the middle part, so that its positioning on the middle part before blocking is facilitated.

Preferably, the first element is the bottom and the second element is the middle part.

Advantageously, the peripheral sidewall portion of the bottom is located furthest outwardly from the peripheral side wall portion of the middle part.

Brief description of the figures

• les figures 1 et 2 sont des vues respectivement en plan de dessous et de dessus de la carrure seule et du fond seul, certaines dimensions ayant été exagérées ;
• la figure 3 est une vue en plan de dessous de la boîte sur laquelle le fond, représenté en traits mixtes, est engagé sur la carrure mais n'est pas bloqué sur celle-ci ;
• la figure 4 est une vue analogue à celle de la figure 3, le fond étant engagé sur la carrure et bloqué sur celle-ci ;
• la figure 5 est une vue en coupe partielle faite selon la ligne V-V de la figure 3, et
• la figure 6 est une vue en coupe partielle faite selon la ligne VI-VI de la figure 4.

Other features and advantages of the present invention will emerge more clearly from a reading of the following detailed description of an exemplary embodiment of a sealed watch case according to the invention, this example being given purely for illustrative purposes and not limiting only in connection with the appended drawing in which:

• the figures 1 and 2 are views respectively in plan from below and from above the middle and the bottom alone, some dimensions having been exaggerated;
• the figure 3 is a bottom plan view of the box on which the bottom, shown in phantom, is engaged on the middle part but is not blocked on it;
• the figure 4 is a view similar to that of the figure 3 , the bottom being engaged on the middle part and blocked on this one;
• the figure 5 is a partial sectional view taken along line VV of the figure 3 , and
• the figure 6 is a partial sectional view taken along line VI-VI of the figure 4 .

Detailed description of an embodiment of the invention

Referring in particular to figures 5 and 6 attached to this patent application, the sealed watch case according to the invention, generally designated by the general numerical reference 1, comprises in particular two elements respectively forming a middle part 2 of generally circular shape and a bottom 4 of circular shape as well. . The middle 2 is provided with two pairs of horns 6.

According to the invention, the bottom 4 and the middle part 2 are made of a material whose hardness is at least 1000 HV. A preferred example of a material having a hardness of at least 1000 HV is a ceramic, particularly a sintered zirconia oxide.

Thanks to these features, the present invention provides a waterproof watch case in which the bottom and the middle part are made of a material having a hardness of at least 1000 HV. Materials that meet this definition include ceramics, for example sintered zirconia. It is known that such ceramics offer great possibilities in terms of shapes and choice of colors. Nevertheless, the substitution of steel by ceramics was not without difficulty. Indeed, ceramics are extremely hard and fragile materials. The skilled person was therefore of the opinion that the very low ductility of the ceramic materials would not allow a corresponding bottom and middle made of such a material to deform sufficiently so that their facing surfaces can marry properly when the bottom is tight on the middle to ensure a sufficient resultant clamping force. On the other hand, the skilled person also feared that the thin nets whose machining is made necessary by the watch cases of the type of object of the present patent application would be too fragile and could break due to fragility. ceramic materials. All concurred thus to divert the skilled person from the choice of a hard material for the realization of the components of a waterproof watch case according to the invention. Now, to his surprise, the Applicant has found, after several attempts, that the prejudices of the person skilled in the art were unfounded and that components, bottoms and frames, for waterproof watch cases could be made of ceramic and present all the required guarantees, particularly in terms of clamping force and mechanical strength. In addition, thanks to the choice of materials of great hardness such as ceramics, designers enjoy great freedom both in terms of choice of shapes than colors.

According to a complementary feature of the invention, the bottom 4 comprises an annular peripheral shoulder 8 which receives a seal 10 intended to be compressed between a first bearing surface 12 of the annular peripheral shoulder 8 and a lower face 14 2. This arrangement makes it possible to avoid having to machine an annular groove in the lower face 14 of the caseband 2, an operation that is made difficult because of the hardness of the caseband 2 and the diameter of this annular groove, necessarily smaller. the diameter of the bottom 4.

The annular peripheral shoulder 8 is extended radially outwards in the manner of a stair step by an annular flange 16 delimited internally by a first peripheral side wall portion 20. This first peripheral side wall portion 20 is extends in height between two planes P1 and P2 which are materialized respectively by the first bearing surface 12 of the annular peripheral shoulder 8 and by a second bearing surface 22 of the annular flange 16. In the example shown in the drawing, the first peripheral side wall portion 20 is undercut, that is to say that it is slightly inclined with respect to a closure axis O-O ' which, in the example shown, coincides with the axis geometric case of the waterproof watch case 1, that is to say the axis parallel to the axis of rotation of the needles. Preferably, the angle of inclination of the first peripheral side wall portion 20 is of the order of 10 °.

The inner face or surround 24 of the middle part 2 comprises, in its part adjacent to the lower face 14, a second peripheral side wall portion 26 forming a groove 28 open towards the inside. This second peripheral side wall portion 26, also undercut, is delimited in height by two planes P3 and P4 which are respectively materialized by a third and a fourth bearing surfaces 30 and 18 of the groove 28.

The profile of the second peripheral side wall portion 26 of the middle part 2 is complementary to that of the first peripheral side wall portion 20 of the bottom 4. In other words, the inclination of the second peripheral side wall portion 26 is substantially equal to to that of the first peripheral sidewall portion 20 of the bottom 4. With regard to the inclination of the first and second peripheral sidewall portions 20 and 26, it will finally be noted that their conicity is, in the illustrated example, directed in the direction from the bottom 4.

It will be understood that the first and second peripheral side wall portions 20 and 26 of the bottom 4 and the middle part 2 are arranged so that, in a first angular position of the bottom 4 with respect to the axis O-O ' ( figure 3 ), the bottom 4 can be separated from the middle part 2 and that, in a second angular position ( figure 4 ) In which the base 4 is rotated by a predetermined clearance angle Ω about the axis O-O 'from the first angular position, the bottom 4 is stuck on the middle part 2 by compressing the gasket 10. Moreover, the Hf height which corresponds to the distance between the planes P1 and P2 is less than the height Hc which corresponds to the distance between the planes P3 and P4 , so that the second bearing surface 22 of the annular flange 16 does not come into contact with the third bearing surface 30 of the groove 28 in the second angular position of the bottom 4 as defined above.

With particular reference to Figures 1 to 4 it can be seen that the peripheral lateral wall portion 26 of the caseband 2 comprises four circularly arcuate sections 32, two successive circular arcuate sections 32 each being connected to each other by a reentrant section 34 oriented towards each other. substantially radially to form a projection 36. Each arcuate section 32 occupies a circular arc Ac close to 90 ° and is centered on a point Cc offset from the closure axis OO 'which, in the particular example , in the example described and illustrated, the sections 32 in an arc have the same radius Rc , so that the centers Cc of each of these sections 32 are arranged on a circle 38 (shown in phantom) centered on the closing axis OO '.

As mentioned in the previous paragraph, the arcuate sections 32 which form the peripheral side walls 26 of the middle part 2 are eccentric with respect to the closure axis O-O ' and the distance of their points with respect to the axis O-O' varies progressively when one traverses the sections in an arc of circle 32 over their entire length. In the example illustrated, this distance increases when one traverses the arcuate sections 32 in the counterclockwise direction from below.

The peripheral side wall portion 20 of the bottom 4 also comprises four circular arcuate sections 40 each centered on a point Cf offset from the geometric closure axis O-O ' . Each arcuate section 40 occupies a circular arc Af less than 90 °, for example about 80 °, and has the same radius Rf, so that the centers Cf of arcuate sections 40 are arranged on a circle 42 (shown in phantom) centered on the closing axis O-O ' .

Each of the arcuate segments 40 of the bottom 4 is associated with an arcuate section 32 of the middle part 2, these arcuate sections 32, 40 associated with each other having substantially the same radius, so that the circles 38 and 42 are merged. It will be noted that the value of the angle Δf corresponds substantially to the value of the angle Δf deduced from the clearance angle Ω.

However, unlike the arcuate segments 32 of the middle part 2, two successive arcuate segments 40 of the bottom 4 are connected to each other by a broken profile portion 44 which defines a clearance 46 of depth such that it allows the passage of the projections 36 of the middle part 2 in the first angular position ( figure 3 ). The broken profile portion 44 comprises a first part 48 which extends from the end of a section in an arc of circle 40 and approaches the closing axis O-O ' substantially to the right of the end the next arcuate section 40 to join the latter by a second portion 50 extending substantially radially.

Thus, thanks to the profile of the peripheral lateral wall portions 20 and 26 respectively of the bottom 4 and the middle 2 of the invention and in particular of the broken profile of the peripheral side wall 20 of the bottom 4, the flange 16 of the bottom 4 can, in the first angular position represented in the figure 3 , to be engaged freely in the opening of the middle part 2, the sections 40 of the bottom 4 at that time eccentric with respect to the sections 32 of the middle part 2 which correspond to them. It then suffices to turn the bottom 4 relative to the middle part 2 by a predetermined clearance angle Ω from the first angular position to bring it into the second angular position ( figure 4 ) in which each section 40 of the bottom 4 is concentric with the portion 32 of the middle part 2 which is associated with it to ensure the locking of the bottom 4 on the middle part 2. During this rotation which makes it possible to pass the bottom 4 of its first angular position at its second angular position, the annular flange 16 of the bottom 4 penetrates gradually into the middle part 2, thus causing compression of the seal 10 and bringing each section 40 of the bottom 4 in intimate contact over its entire surface with the section 32 of the middle part 2 associated with it, thus ensuring effective blocking of the bottom 4 on the middle part 2.

The clearance angle Ω is the minimum angle necessary to disengage the first peripheral side wall portion 20 from the second peripheral side wall portion 26 during the pivoting of the bottom 4 into the middle part 2. In the illustrated example, this angle clearance is of the order of 20 °.

Preferably, the clearance angle Ω will be as small as possible so that the contact area between the first and second peripheral side wall portions 20 and 26 is as large as possible, so as to obtain a better blocking of the bottom 4 on 2. It will thus obtain a compression of the seal 10 over a larger part of its perimeter.

Although in the embodiment of the invention just described, the peripheral side wall portion 20 of the bottom 4 is external and the peripheral side wall portion 26 of the middle part 2 is internal, it is obvious that according to an alternative embodiment could be provided the opposite. In the latter case, a flange similar to the annular flange 16 is formed on the middle part 2 instead of the open groove 28 formed, in the example described above, by the peripheral side wall portion 26, and a groove similar to the latter is formed in the bottom 4 in place of the annular flange 16.

It is understood that other embodiments of the waterproof watch case according to the invention may still be envisaged. For example, there may be provided watch cases whose sidewall portions of the bottom and the middle have respectively two, three, five or more sections in an arc. In this case, the shape of the broken profile portion connecting the bottom sections can of course vary.

While in the embodiment of the watch case described above all the arcuate portions of a peripheral side wall portion of one or the other of the first and second elements, bottom or middle, present the same radius, it can be provided that the arcuate sections of the first element have different radii and that the arcuate sections of the other element have radii corresponding to those of the first element.

It will be noted that the relative dimensions of the arcuate sections have deliberately been exaggerated to facilitate understanding of the invention.

Nomenclature

• Waterproof watch box 1
• Carrure 2
• Background 4
• Horns 6
• Ring peripheral shoulder 8
• Gasket 10
• First support surface 12
• Bottom 14
• Ring flange 16
• First portion of peripheral side wall 20
• P1 and P2 plans
• Second support surface 22
• Closing axis O-O '
• Inside or around 24
• Second portion of peripheral side wall 26
• Groove 28
• P3 and P4 shots
• Third bearing surface 30
• Clearance angle Ω
• Height Hc
• Stretches in an arc 32
• Incoming section 34
• Projection 36
• Arc of circle Ac
• Point Cc
• Radius Rc
• Circle 38
• Stages in an arc 40
• Point Cf
• Circle 42
• Broken profile portion 44
• Clearance 46
• First part 48
• Second part 50

Claims (9)

Watertight watch case comprising two elements respectively forming a middle part (2) and a bottom (4), a seal (10) being interposed between these two elements, a first of these elements comprising a first peripheral side wall portion ( 20) which extends in height, the second member also having a second upstanding peripheral side wall portion (26) which is of complementary shape to the first wall portion lateral peripheral (20) of the first element, the first and second peripheral side wall portions (20, 26) of the first and second elements being arranged so that, in a first angular position with respect to a pivot axis called closure axis (O-O '), the first element can be dissociated from the second element and that, in a second angular position in which the first element is t rotated by a predetermined angle (Ω) about said closure axis (O-O ') from the first position, the first member is locked in the second member by compressing the packer (10), the box waterproof watch characterized in that the bottom (4) and the middle (2) are made of a material whose hardness is at least 1000 HV. Waterproof watch case according to claim 1, characterized in that the material in which the bottom (4) and the middle part (2) are made is a ceramic. Sealed watch case according to claim 2, characterized in that the base (4) and the middle part (2) are made of sintered zirconia oxide. Waterproof watch case according to any one of claims 1 to 3, characterized in that the bottom (4) comprises a annular peripheral shoulder (8) which receives a seal (10) arranged to be compressed between a first bearing surface (12) of the annular peripheral shoulder (8) and a lower face (14) of the middle part ( 2). Sealed watch case according to any one of claims 1 to 4, characterized in that the second peripheral side wall portion (26) of the second element comprises at least two circular arcuate segments (32) each centered on a point ( Cc) offset from the closure axis (O-O '), these two sections (32) being connected to each other by a reentrant section (34) to form projections (36), the first peripheral side wall portion (20) of the first element comprising in turn at least two circular arcuate segments (40) each centered on a point (Cf) offset relative to the closure axis (O-O '), these two sections (40) being connected to one another by a section (44) whose profile is broken and which defines a clearance (46) of depth such that it allows, in the first angular position, the passage protrusions (36) of the second member in the recesses (46) of the first member. Sealed watch case according to claim 5, characterized in that each arcuate section (40) of the first element is associated with an arcuate section (32) of the second element, the associated sections (40; to one another having substantially the same radius (Cf; Cc) so that in the first angular position each arcuate section (40) of the first member is eccentric with respect to the arcuate section (32). ) of the second element which is associated with it, while in the second angular position, each arcuate section (40) of the first element is concentric with the arcuate section (32) of the second element which is associated therewith. Sealed watch case according to claim 6, characterized in that the peripheral side wall portion of the first and second elements comprises four sections in an arc regularly distributed along the perimeter of the first and second elements. Waterproof watch case according to any one of claims 1 to 7, characterized in that the first element is the bottom (4) and the second element is the middle part (2). Sealed watch case according to claim 8, characterized in that the peripheral side wall portion (20) of the base (4) is located furthest outwardly from the peripheral side wall portion (26) of the middle part (2).

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