Depth gauge seal

Abstract

The present invention relates to a depth gauge seal. One aspect of the present invention relates to a seal (21, 121) for a depth gauge (1) having a rotational axis (Z), which includes a radially inner side (213, 223) and a radially outer side (214, 224), and is characterized in that the height (h1) of the radially inner side (213, 223) of the seal (21, 121) is greater than the height (h2) of the radially outer side (214, 224).

Description

Field of the Invention

[0001] The field of the invention relates to a device for sealing a depth gauge that is subject to fluid pressure.

[0002] The invention more particularly relates to a seal for a depth gauge, and more particularly to a seal for a mechanical depth gauge that includes a membrane pressure sensor, the seal ensuring the tightness at the level of the membrane pressure sensor.

[0003] The invention also relates to a timepiece that includes such a mechanical depth gauge. Background Art

[0004] As Figure 1 illustrated, the mechanical depth gauge 1 makes it possible to indicate, for example, the water depth by means of a rotary pointer 2 facing a scale 3 of a dial 4, in particular using a pressure sensor housed in a depth gauge housing 6. The pressure sensor is generally connected to the pointer 2 by a mechanical transmission means.

[0005] The pressure sensor is generally housed in a pressure chamber arranged in the housing 6, such a pressure chamber being intended to receive a pressurized fluid.

[0006] In a mechanical depth gauge, the pressure sensor generally includes a deformable membrane (for example in the form of a metal disc including concentric undulations) in order to vary the amplitude of the elastic bending.

[0007] In order to fasten such a pressure sensor and ensure the tightness between the interior and the exterior of the depth gauge housing, it is known to weld the deformable membrane, see for example patent application DE 10 147 124, or to clamp the deformable membrane as proposed in document WO 01 / 01098. However, the manufacture of these deformable membranes is relatively complex and does not have a satisfactory reproducibility. In addition, if the pressure sensor is subject to a pressure exceeding its service pressure, it is not easy to ensure that the deformable membrane will not enter its plastic deformation range.

[0008] To remedy these drawbacks, manufacturers have replaced these metal discs with undulations with flat deformable membranes, but the fastening method still presents rather significant drawbacks. In fact, if the peripheral region of the deformable membrane is welded to the sensor structure, this reduces the elastic deformation that the membrane can withstand before plastic deformation, and thus reduces the sensitivity of the pressure sensor.

[0009] In addition, welding introduces different hardness characteristics for each solder. The resulting inaccuracy regarding the bending of the deformable membrane significantly reduces the accuracy of the sensor, and furthermore makes it difficult to use a stop to prevent the plastic deformation of the deformable membrane. Fastening the deformable membrane by means of its arrangement in the sensor structure also has some of the above-mentioned drawbacks.

[0010] To partly remedy these drawbacks, a pressure sensor with a simple design has been proposed, which enables the deformable membrane to bend as freely as possible under fluid pressure while maintaining satisfactory sealing, thanks to the use of seals.

[0011] Thus, document EP 2 264 399 proposes not to rigidly connect the peripheral region of the deformable membrane to the body or the cover of the depth gauge, so that when the deformable membrane bends under the action of an increasing fluid pressure in the pressure chamber, the peripheral region of the deformable membrane can pivot on a stop. This structure is shown by Figure 2 shown Figure 2 illustrates the peripheral region of the housing 6 of the depth gauge 1.

[0012] To ensure the sealing of such an assembly, an O-ring type seal 7 is compressed against the peripheral region of the deformable membrane 8 to ensure the sealing of the inner volume of the depth gauge relative to the pressure chamber 10. The seal 7 also serves as a support element to constantly press the peripheral region of the deformable membrane 8 against the stop 9, especially when the deformable membrane 8 pivots.

[0013] The O-ring 7 is housed in a circular groove 11 formed at the bottom of the depth gauge, which circular groove has a rectangular profile. Such a circular groove 11 has the advantage of facilitating the positioning of the O-ring 7 during assembly. Such a circular groove 11 also makes it possible to limit the radial expansion of the O-ring 7 and thus the deformation of the deformable membrane 8 during assembly as well as during pressurization of the pressure chamber 10. Thus, the circular groove 11 makes it possible to ensure sufficient contact pressure on the deformable membrane 8 to ensure the required sealing within the operating range of the depth gauge.

[0014] However, in the case of intensive use of the depth gauge, as described in application EP 2 264 399 and Figure 2 illustrated in, and / or in the case of poor cleaning of the depth gauge by the user, salt residues can accumulate in or near the circular groove 11, thereby leading to the risk of corrosion in this area and premature wear of the deformable membrane 8. Summary of the Invention

[0015] In this context, the present invention proposes a novel depth gauge seal having a profile that is particularly suitable for use at the pressure sensor, especially having a deformable membrane, so that it is possible to correctly ensure the level of sealing required for such use while making it possible to simplify the geometry of the different elements at the sealing area of the depth gauge in order to prevent the accumulation of salt residues in the peripheral region of the deformable membrane.

[0016] To this end, the present invention relates to a seal for a depth gauge having a rotational axis Z, the seal comprising a radially inner side and a radially outer side, characterized in that the height of the radially inner side of the seal is greater than the height of the radially outer side.

[0017] In addition to the features mentioned in the previous paragraph, the seal according to the present invention may have one or more of the following additional features considered individually or in any technically possible combination:

[0018] - The seal has a cross-section along a radial cutting plane, the cross-section having a polygonal shape;

[0019] - The cross-section has a trapezoidal shape including two parallel sides, the two parallel sides of the trapezoid being formed by the radially outer side and the radially inner side;

[0020] - The cross-section has a top surface, the top surface including at least one inclined flat portion with respect to the bottom surface;

[0021] - The top surface includes a first flat portion parallel to the bottom surface and a flat portion inclined with respect to the bottom surface;

[0022] - The at least one inclined flat portion has an inclination with respect to the bottom surface, the inclination being greater than 0° and less than or equal to 45°;

[0023] - The seal has a cross-section along a radial cutting plane, the cross-section having a quarter-circle shape;

[0024] - The seal is made of an elastomer, preferably made of nitrile;

[0025] - The seal is configured to be compressed against a deformable membrane of a depth gauge pressure sensor.

[0026] The present invention also relates to a depth gauge, which comprises:

[0027] - A housing closed at the bottom, the bottom defining a pressure chamber in fluid communication with the outside of the depth gauge,

[0028] - A pressure sensor, which includes a deformable membrane disposed above the pressure chamber;

[0029] - A seal according to the present invention, the seal ensuring the sealing of the housing with respect to the pressure chamber.

[0030] Advantageously, the seal is compressed and forms a support element for the deformable membrane.

[0031] Advantageously, the seal is disposed at the peripheral region of the deformable membrane.

[0032] Advantageously, when the deformable membrane is deformed under the action of an increasing pressure in the pressure chamber, the peripheral region of the deformable membrane can pivot by pressing against the seal.

[0033] Advantageously, the bottom is not provided with a channel or a groove for receiving the seal.

[0034] Advantageously, the bottom includes a top surface defining the bottom part of the pressure chamber, and the seal is directly located on the top surface of the bottom defining the bottom part of the pressure chamber.

[0035] Advantageously, the depth gauge includes an indexing member (organe d’indexage) provided on the top surface of the bottom to facilitate the centering of the seal.

[0036] Advantageously, the seal defines the peripheral part of the pressure chamber.

[0037] Advantageously, the deformable membrane is formed by a metal disc or by a disc of an amorphous metal alloy.

[0038] Advantageously, the disc is flat.

[0039] The invention also relates to a timepiece, such as a watch, in particular a diving watch, comprising a depth gauge according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The objects, advantages and features of the invention will become apparent upon reading the following detailed description with reference to the following drawings.

[0041] - Figure 1 is a schematic front view of a depth gauge equipped with a membrane pressure sensor according to the prior art;

[0042] - Figure 2 is Figure 1 a partial radial cross-section view along line II-II of the peripheral region of the depth gauge illustrated according to the prior art;

[0043] - Figure 3 is a schematic and partial radial cross-sectional view of an embodiment example of a depth gauge according to the invention, the depth gauge being equipped with a seal and a membrane pressure sensor according to the invention;

[0044] - Figure 4 is Figure 3 an enlarged view of detail III in which is more particularly shown the peripheral region of the pressure sensor and the seal according to the invention when the depth gauge is not subjected to an external pressure greater than atmospheric pressure;

[0045] - Figure 5 is Figure 3Enlarged view of detail III, which more particularly shows the peripheral area of the pressure sensor and the seal according to the invention when the depth gauge is subjected to an external pressure greater than atmospheric pressure;

[0046] - Figure 6 is a schematic view of a cross-section along a radial cutting plane of a first exemplary embodiment of a seal according to the invention;

[0047] - Figure 7 is a schematic view of a cross-section along a radial cutting plane of a second exemplary embodiment of a seal according to the invention;

[0048] - Figure 8 is Figure 6 an alternative embodiment of the first exemplary embodiment of the seal shown according to the invention.

[0049] In all the figures, unless otherwise indicated, common elements have the same reference numerals. Detailed Description

[0050] has been described in the preamble of the present invention Figure 1 and Figure 2 .

[0051] Figures 3 to 5 Schematically shows a depth gauge 100 along the axis of rotation Z according to the invention.

[0052] For example, the depth gauge 100 is a depth gauge for being worn on a user's wrist, thanks to a wristband (not shown). Generally, a pressure sensor 17 housed in a housing 6 of the depth gauge 100 is used. The depth gauge 100 according to the invention includes a pointer 2 indicating the water depth, and the pointer 2 rotates facing a scale 3 provided on a dial 4.

[0053] The pressure sensor 17 located at the bottom of the housing 6 is connected to the pointer 2 through a mechanical transmission member 19, and the mechanical transmission member 19 is configured to convert the axial movement of the pressure sensor 17 along the axis of rotation Z of the depth gauge 100 into a rotational movement around the axis of rotation Z.

[0054] The transmission member 19 particularly includes a rotating shaft 22 equipped with a palpeur 23. Obviously, other mechanical transmission member structures can be conceived without departing from the present invention.

[0055] It will be noted that the depth gauge 100 can be combined with a watch in the same housing 6, particularly a diving watch, however this is not necessary. In this case, the housing 6 also includes a watch movement (not shown), and the dial 3 has scales to indicate information related to time information.

[0056] The housing 6 is closed by the drilled bottom 11. The pressure sensor 17 is mounted, for example, on the bottom 11 of the housing 6, as Figures 3 to 5 illustrated.

[0057] The pressure sensor 17 is arranged above a pressure chamber 29 defined by the bottom 28. The pressure chamber 29 communicates with the outside of the housing 6 through a hole 30, such that the pressure chamber 29 is in fluid communication with the outside of the depth gauge 100. Thus, the fluid contained in this pressure chamber 29 is subjected to the dominant pressure surrounding the depth gauge 100.

[0058] The pressure sensor 17 includes a deformable membrane 12, for example flat and circular, wherein the peripheral region 13 is clamped between the bottom 28 and a rigid stop 14 fastened in the housing 6, and the rigid stop is capable of restricting the deformation of the deformable membrane 12 of the pressure sensor 17.

[0059] In Figure 3 the illustrated exemplary embodiment, the rigid stop 14 is provided with a central opening 15, in particular for inserting the feeler rod 23. Thus, the feeler rod 23 can move vertically in the opening 15 and pivot the shaft 22 according to the displacement (deformation) of the deformable membrane 12.

[0060] Obviously, depending on the structure of the transmission member used, the shape of the rigid stop 14 can be different and does not have a central opening 15.

[0061] A return spring (not shown) keeps the free end of the feeler rod 23 pressed against the deformable membrane 12 to ensure permanent contact between these two elements.

[0062] Between the opening 15 and the peripheral region 13 of the deformable membrane 12, the rigid stop 14 has a slightly concave bottom surface, which together with the deformable membrane 12 defines a chamber 18, and the chamber 18 communicates with the rest of the inner volume of the housing 6 through the opening 15. This concave surface forms a stop surface 20 to limit the bending of the deformable membrane 12 when the deformable membrane 12 is subjected to a pressure difference exceeding the limit pressure, and the limit pressure will be defined hereinafter.

[0063] The inner volume of the housing 6 contains air or another gas at a reference pressure.

[0064] A seal 21 having a rotational axis Z is compressed against the deformable membrane 12 (more specifically, at the peripheral region 13 of the deformable membrane 12) and ensures the sealing of the inner volume of the housing 6 relative to the pressure chamber 29 and the outside of the housing 6.

[0065] The seal 21 also forms a support element for the deformable membrane 12, which is configured to constantly press the peripheral region 13 of the deformable membrane 12 against the rigid stop 14, regardless of the deformation state of the deformable membrane 12. The compression of the seal 21 against the deformable membrane enables sufficient contact pressure to be obtained to ensure the sealing of the housing 6.

[0066] As Figure 5 illustrated ( Figure 5 more specifically illustrated in the peripheral region of the pressure sensor 17 and the seal 21 according to the present invention), when the deformable membrane 12 deforms and the pressure sensor 17 is subjected to the pressure difference between the chambers 29 and 18, the seal 21 is configured such that the peripheral region 13 of the deformable membrane 12 can pivot while ensuring the contact pressure required to ensure the sealing of the internal volume of the housing 6.

[0067] The bottom 28 has a vertical edge 24 arranged in the peripheral region of the bottom 28, which abuts against the rigid stop 14 adjacent thereto, and the height of the vertical edge 24 is selected such that the seal 21 is greatly prestressed against the deformable membrane 12 (as Figure 4 illustrated) to ensure the sealing between them throughout the operating pressure range of the pressure sensor 17 of the depth gauge 100.

[0068] The compression of the seal 21 presses the peripheral region 13 of the deformable membrane 12 against a part of the rigid stop 14 (i.e., the support band 25 along the edge of the concave stop surface 20 and actually positioned facing the seal 21). In this example, the support band 25 is flat, but it can also have a rounded or ridged transverse profile.

[0069] The material and thickness of the deformable membrane 12 are selected such that: throughout the entire pressure range that the sensor 17 will withstand, the deformation of the deformable membrane 12 remains within the elastic range.

[0070] The deformable membrane 12 is made of materials commonly used by those skilled in the art and known for such applications.

[0071] Preferably, the deformable membrane 12 is a metal disc or a disc made of an amorphous metal alloy (also known as metallic glass).

[0072] Thanks to the flat shape of the deformable membrane in the resting state, the method for manufacturing the deformable membrane is easy to implement, for example, by cutting in a stainless steel plate. In addition to the seal 21, other elements of the pressure sensor 17 can be made of metal or a rigid synthetic material, for example.

[0073] When the depth gauge 100 is immersed to a certain depth in water, the deformable membrane 12 elastically bends under the increased pressure difference between the chambers 29 and 18 located on either side of the deformable membrane 12. The bending of the deformable membrane 12 is transmitted to the touch rod 23. The mechanical transmission of the transmission member 19 between the touch rod 23 and the pointer 2 is arranged to produce an actual linear movement of the pointer 2 according to the pressure change. However, depending on the transmission member 19 and the different gear trains used, a non-linear movement of the pointer 2 can also be produced. In this case, the dial will have a non-linear scale 3.

[0074] For the above-mentioned limit pressure, the shape given to the stop surface 20 advantageously corresponds to the contour of the deformed shape of the deformable membrane 12. This contour (theoretically parabolic for a circular membrane, where the bending is small in this case) can be approximated by a spherical dome shape that is easy to machine. Preferably, the limit pressure is slightly greater than the maximum operating pressure of the depth gauge 100. Since depth gauges usually have to withstand a much greater maximum test pressure than the maximum operating pressure, the main role of the stop surface 20 is to prevent the deformable membrane 12 from undergoing plastic deformation under these test conditions, because the deformable membrane 12 is then blocked (épauler) by a rigid stop 14 that is much more rigid than it.

[0075] In Figures 3 to 5 In the illustrated example of the embodiment, only the central part of the deformable membrane 12 facing the opening 15 may undergo additional bending, but the additional stress is reduced and, with appropriate sizing, it can be kept within the elastic range. Obviously, these advantages also exist in cases where the pressure sensor accidentally withstands excessive pressure, such as water hammer in a pressure gauge.

[0076] Assuming that the peripheral region 13 of the deformable membrane 12 is neither welded nor set in a structure that supports it, it can pivot almost freely on the support strip 25 to tilt and approach the stop surface 20.

[0077] It will also be noted that a countersunk hole 26 is arranged between the seal 21 and the vertical edge 24 to enable the edge of the deformable membrane 12 to freely lower during the deformation of the deformable membrane.

[0078] Figure 6 Represents a first example of an embodiment of the seal 21 according to the present invention, and Figure 7 Represents a second example of an embodiment of the seal 121 according to the present invention.

[0079] Figure 6 More specifically, a cross-section S of a first example of an embodiment of the seal 21 according to the present invention along a radial cutting plane in its non-compressed state is schematically illustrated.

[0080] Figure 7More specifically, a second exemplary embodiment of the seal 121 according to the present invention is schematically illustrated in a cross-section S' along a radial cutting plane in its non-compressed state.

[0081] Unlike the seals known from the prior art described in the preamble of the present invention, the seals 21, 121 according to the present invention have a non-circular cross-section and are asymmetric between a radially inner part Pi and a radially outer part Pe. Figure 2 In

[0082] In Figure 6 and Figure 7 , the radially inner part Pi is located on the left side of a dashed axis which represents the center of the width L of the cross-sections S, S' of the seals 21, 121, while the radially outer part Pe is located on the right side of said dashed axis.

[0083] The expressions "radially inner" and "radially outer" are clearly to be considered with respect to the depth gauge 100 and the axis of rotation Z of the seals 21, 121, which two axes of rotation coincide. Thus, the radially inner part, side or face is radially closer to the axis of rotation Z than the radially outer part, side or face.

[0084] The term "side" refers to the lateral part of the seals 21, 121.

[0085] As Figures 6 to 8 shown, the seals 21, 121 in their non-compressed state have a radially inner side 213, 223 whose height h1 is greater than the height h2 of the radially outer side, thus resulting in a difference in the material thickness between the radially inner part Pi and the radially outer part Pe of the seals 21, 121.

[0086] For example, the ratio of the height h1 of the radially inner side 213, 223 to the height h2 of the radially outer side 214, 224 is between 2 and 1.25.

[0087] For example, the height h1 of the radially inner side 213, 223 is equal to the width L of the seals 21, 121.

[0088] The difference in height between the radially inner side 213, 223 and the radially outer side 214, 224 makes it possible to advantageously obtain a difference in the material volume between the radially inner part Pi and the radially outer part Pe of the seals 21, 121.

[0089] When the deformable membrane 12 deforms and pivots at the seals 21, 121, this difference between the radially inner part Pi and the radially outer part Pe makes it possible to maintain sufficient contact pressure over the entire contact surface area of the seal 21, so as to release, during the clamping and mounting of the bottom 28 onto the housing 6, the contact pressure previously obtained during the compression of the seals 21, 121. In fact, when the deformable membrane 12 deforms under a positive pressure, it will move towards the rigid stop 14 and thus away from the housing bottom 28.

[0090] The seals 21, 121 according to the invention have such a geometry that it makes it possible to advantageously dispense with the use of channels or grooves (as Figure 2 shown) usually arranged at the bottom for receiving the seals, and thus dispense with the need to have a support surface at their radially inner part in order to radially pressurize the seals, with the aim of restricting their radial expansion and maintaining sufficient compression during the deformation of the deformable membrane 12, so as to ensure the required level of tightness.

[0091] In fact, the seals 21, 121 according to the invention have sufficient rigidity, especially at their radially inner part Pi, so as not to require a support surface capable of restricting their radial expansion during their compression against the deformable membrane 12.

[0092] Thus, the seals 21, 121 according to the invention make it possible to ensure the tightness of the housing 6 over the entire operating pressure range of the pressure sensor 5 of the depth gauge 100, while the overpressure in such channels or grooves causes salt residues to accumulate in this area in the peripheral region 13 close to the deformable membrane 12.

[0093] Thus, the seals 21, 121 according to the invention make it possible to advantageously remove any ribs, roughnesses that promote the accumulation of salt residues in the case of poor cleaning of the depth gauge 100, while ensuring the required level of tightness within the operating range of the depth gauge 100.

[0094] The seals 21, 121 according to the invention are advantageously located directly on the top surface 28a of the bottom part of the bottom 28 that delimits the pressure chamber 29, the top part of the pressure chamber 29 being delimited by the bottom surface of the deformable membrane 12.

[0095] With the seals 21, 121 according to the invention, the peripheral part of the pressure chamber 29 is directly delimited by the seals 21, 121 and in particular by their radially inner sides 213, 223.

[0096] However, as Figure 4 and Figure 5As shown, the bottom 28 may have a wall 27 in a radially outer region relative to the seals 21, 121. The wall 27 is, for example, vertical or slightly inclined and can form a lateral stop for positioning the seals 21, 121. Thus, sliding of the seals during assembly is prevented, and correct positioning of the seals 21, 121 facing the support band 25 of the rigid stop 14 is ensured. This region is not in communication with the fluid circulating in the pressure chamber 29, there is no risk of salt residue accumulation, and thus no risk of premature deterioration of the deformable membrane 12.

[0097] Referring Figure 6 , a first exemplary embodiment of the seal 21 has a cross-section S that is of a polygonal shape, and more specifically a trapezoidal shape including two parallel sides. The two parallel sides of the trapezoid are formed by the radially outer side 214 and the radially inner side 213 of the seal.

[0098] The cross-section S of the seal 21 has flat surfaces that are separated from each other by rounded sections that form connection portions between different flat surfaces or faces.

[0099] More specifically, the seal 21 includes four flat faces:

[0100] - A bottom face 211;

[0101] - A top face 212;

[0102] - A radially inner side face that forms the above-mentioned radially inner side 213, and

[0103] - A radially outer side face that forms the above-mentioned radially outer side 214.

[0104] The rounded sections connecting the different faces have an arcuate cross-section, and the rounded surfaces can have a relatively large radius of curvature.

[0105] Preferably, the radially inner side face and the radially outer side face extend in a direction substantially perpendicular to the bottom face 211. Thus, the sides 213, 214 of the seal 21 extend substantially perpendicular to the bottom face 211.

[0106] The top face 212 of the seal 21 has at least one portion that is inclined with respect to the bottom face 211, for example, an inclination greater than 0° and less than or equal to 45°.

[0107] In Figure 6 the illustrated exemplary embodiment, the entire top face 212 is inclined. However, according to Figure 8In the illustrated alternative embodiment, it is also conceivable that the top surface 212 has a first flat portion 212a parallel to the bottom surface 211 and a second flat portion 212b inclined with respect to the bottom surface 211. In this case, the inclined flat portion 212b will be located in a radially outer region with respect to the first flat portion 212a.

[0108] As explained above, the inclination of at least a portion of the top surface 212 of the seal 21 intended to be in contact with the deformable membrane 12 makes it possible to further improve the performance of the seal 21 during pivoting of the deformable membrane 12.

[0109] The inclination of at least a portion of the top surface 212 of the seal 21 also makes it possible to ensure an optimal and more uniform contact pressure during deformation of the deformable membrane 12, regardless of the pressure prevailing in the chamber 29.

[0110] Over the entire operating pressure range of the depth gauge 100, producing at least one inclined top surface makes it possible to ensure a sufficient level of contact pressure between the seal 21 and the deformable membrane 12.

[0111] Thus, due to this specific geometry, the seal 21 according to the invention makes it possible to compensate for the pressure losses caused by the removal of the support walls formed by the channels or grooves during pivoting of the deformable membrane 12. Thus, especially when the membrane is deformed (as Figure 5 illustrated), when the sealing requirements are greatest, and even in the absence of channels or grooves restricting the deployment of the seal, the seal 21 makes it possible to ensure the required level of sealing.

[0112] Furthermore, due to the seal according to the invention, the contact pressure between the deformable membrane 12 and the bottom 28 is more uniform over the entire surface area compared to a circular O-ring without channels or grooves.

[0113] Figure 7 An example of a second embodiment of the seal 121 according to the invention is illustrated.

[0114] Except as will be described below, the seal 121 is identical to the above-described first embodiment example. Thus, all features described with reference to the first embodiment example also apply to this second embodiment example.

[0115] The seal 121 also includes four flat surfaces:

[0116] - a bottom surface 221;

[0117] - a top surface 222;

[0118] - a radially inner side surface forming the above-mentioned radially inner side 223, and

[0119] - Form the radial outer surface of the above-mentioned radial outer side 224.

[0120] In this second embodiment example, the inclined top surface 212 is replaced by a flat top surface 222, which is substantially parallel to the bottom surface 221 and has a reduced size (e.g., approximately L / 2), and the joint section 225 between the top surface 222 and the radial outer surface 224 has a larger radius of curvature, typically approximately L / 2.

[0121] Therefore, the top surface 222 and the radial outer surface forming the radial outer side 224 have a smaller size than the first embodiment example, typically approximately L / 2.

[0122] The cross-section of the seal 121 according to this second embodiment example can be similar to a quarter-circle shape.

[0123] In the same way as the first embodiment example, according to this second embodiment example, the shape of the seal 121 makes it possible to advantageously eliminate the use of channels or grooves usually arranged at the bottom 28 for accommodating the seal, and eliminate the need for: having a support surface at its radial inner part to radially press on the seal, aiming to limit its radial expansion and maintain the target compression during seal compression, so as to ensure the required sealing level.

[0124] The circular surface 225 with a significantly large surface area also makes it possible to improve the performance of the seal 121 during the pivoting of the deformable membrane 12, so as to ensure the best and uniform contact pressure on the extended surface area.

[0125] Obviously, without departing from the scope of the present invention, other seal cross-sectional profiles can be envisaged, as long as they have a larger material volume at the radial inner part relative to the radial outer part, and the top surface of the seal has such a profile that enables it to follow the pivoting of the deformable membrane 12 when the deformable membrane 12 is under a pressure difference, without losing the uniformity at the contact pressure.

[0126] The seals 21, 121 are made of an elastomer, preferably made of nitrile.

[0127] The bottom 28 may also include indexing elements 31 arranged on at least a part of the top surface 28a of the bottom 28 to facilitate the positioning and centering of the seals 21, 121 without channels or grooves.

[0128] The indexing element 31 forms a protrusion, such as a boss. The indexing element 31 extends circularly on at least a part of the top surface 28a of the bottom 28. Preferably, the indexing element 31 is circular.

[0129] This indexing element 31 forms a visual and / or sensory indicator facilitating the positioning and centering of the seals 21, 121 during assembly. It will be noted that the height of the indexing element 31 is substantially less than the height of the seals 21, 121 or less than the vertical edge 27. In fact, as described and shown, the indexing element 31 is not intended to form a channel or recess for positioning the seals 21, 121, but rather a small boss capable of indicating the correct centering of the seals 21, 121.

[0130] Regarding the assembly of the pressure sensor 17, it is readily understandable that it is particularly simple, especially since it only requires:

[0131] - inserting the rigid stop 14 into the housing 6,

[0132] - positioning the seals 21, 121 on the top face 28a of the bottom 28,

[0133] - mounting the sealing membrane 12 on the seals 21, 121,

[0134] - fastening the bottom 28 to the housing 6 in the usual way; the height of the second vertical edge 24 automatically determines the prestress applied to the seals 21, 121.

[0135] The invention also relates to a timepiece, such as a watch and in particular a diving watch, comprising a depth gauge and a seal according to the invention, which seal is capable of ensuring the tightness of the pressure sensor relative to the timepiece housing.

[0136] The seal according to the invention also makes it possible to achieve the following advantages:

[0137] - ensuring the required tightness regardless of the diving depth and thus regardless of the position of the pressure sensor;

[0138] - being of a size similar to that of seals commonly used in depth gauges (and in particular diving watches);

[0139] - eliminating the corrosion problem in the peripheral area of the deformable membrane by eliminating the channels or recesses for positioning the seal.

Claims

1. A seal for a depth gauge (100) having a deformable membrane, the depth gauge (100) having a rotational axis (Z) and a housing (6) closed by a bottom (28), the seal including a radially inner side and a radially outer side, characterized in that, the height (h1) of the radially inner side of the seal is greater than the height (h2) of the radially outer side, and the seal is configured to seal between the deformable membrane and the bottom (28) to prevent salt residues from accumulating in the peripheral region of the deformable membrane, and the bottom (28) is not provided with a channel or groove for receiving the seal.

2. The seal according to claim 1, characterized in that, the seal has a cross-section along a radial cutting plane, and the cross-section has a polygonal shape.

3. The seal according to claim 2, characterized in that, the cross-section has a trapezoidal shape including two parallel sides, and the two parallel sides of the trapezoid are formed by the radially outer side and the radially inner side.

4. The seal according to any one of claims 2 to 3, characterized in that, the cross-section has a top surface (212), and the top surface includes at least one inclined flat portion with respect to the bottom surface (211).

5. The seal according to any one of claims 2 to 3, characterized in that, the cross-section has a top surface (212), and the top surface (212) includes a first flat portion (212a) parallel to the bottom surface (211) and a flat portion (212b) inclined with respect to the bottom surface (211).

6. The seal according to claim 5, characterized in that, the inclined flat portion (212b) has an inclination with respect to the bottom surface (211), and the inclination is greater than 0° and less than or equal to 45°.

7. The seal according to claim 1, characterized in that, the seal has a cross-section along a radial cutting plane, and the cross-section has a quarter-circle shape.

8. The seal according to any one of claims 1 to 3, characterized in that, the seal is made of an elastomer.

9. The seal according to any one of claims 1 to 3, the depth gauge includes a pressure sensor (17) having a deformable membrane (12), characterized in that, the seal is configured to be compressed against the deformable membrane (12) of the pressure sensor (17).

10. The seal according to any one of claims 1 to 3, characterized in that, the seal is made of nitrile.

11. A depth gauge (100), characterized in that, it includes: - a housing (6) closed by a bottom (28), the bottom (28) defining a pressure chamber (29) in fluid communication with the exterior of the depth gauge (100), - a pressure sensor (17) including a deformable membrane (12) disposed above the pressure chamber (29); - A seal according to any one of the preceding claims, the seal being mounted and compressed between the bottom (28) and the deformable membrane (12), the seal ensuring the sealing of the housing (6) relative to the pressure chamber (29), the bottom (28) not being provided with a passage or groove for receiving the seal.

12. The depth gauge (100) according to claim 11, characterized in that the seal is compressed and forms a support element for the deformable membrane (12).

13. The depth gauge (100) according to claim 12, characterized in that the seal is provided at the peripheral region (13) of the deformable membrane (12).

14. The depth gauge (100) according to claim 13, characterized in that when the deformable membrane (12) is deformed under the action of an increase in pressure in the pressure chamber (29), the peripheral region (13) of the deformable membrane (12) can pivot by pressing on the seal.

15. The depth gauge (100) according to any one of claims 11 to 14, characterized in that the bottom (28) includes a top surface (28a) defining the bottom part of the pressure chamber (29), and the seal is directly located on the top surface (28a) of the bottom (28) defining the bottom part of the pressure chamber (29).

16. The depth gauge (100) according to claim 15, characterized in that the depth gauge (100) includes a centering element (31) arranged on the top surface (28a) of the bottom (28) to facilitate the centering of the seal.

17. The depth gauge (100) according to any one of claims 11 to 14, characterized in that the seal defines the peripheral part of the pressure chamber (29).

18. The depth gauge (100) according to any one of claims 11 to 14, characterized in that the deformable membrane (12) is formed by a metal disc or a disc of amorphous metal alloy.

19. A timepiece comprising a depth gauge (100) according to any one of claims 11 to 18.

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