Semi-impermeable closure device

A portable object includes a case forming a housing inside which is arranged a device that requires air to operate, and a closure device including at least one permeable element. The closure device is arranged to provide impermeability to liquids while allowing the atmosphere inside the housing to communicate with the external atmosphere. The case comprises a recess in which a through opening is made, the recess being closed by the closure device. The closure device includes a permeable module mounted to move such that, in a gaseous environment, the permeable module is in a rest position allowing gases to penetrate the case opening through the permeable module, and in a liquid environment, the permeable module is in an operating position in which gases and liquids are blocked. The permeable module comprises a tubular support at the end of which is fixed a membrane.

The present invention concerns a portable object including a case forming a housing, inside which is arranged a device that requires air to operate.

PRIOR ART

There are known portable objects, such as watches or mobile telephone devices or touch tablets, which are considered to be waterproof to allow for use in an aquatic environment. To this end, said portable object is provided with a multitude of gaskets or solutions for ensuring virtually perfect impermeability both to gases and to liquids. In horology, gaskets are generally used to provide a seal between two moving parts, for example the winding button and the winding stem, or between two fixed parts, for example the case back and case middle.

Thus, for diving, gaskets must be impermeable to helium since molecules that are smaller than oxygen molecules pass through the gasket. When the diver ascends, helium contained inside the watch is degassed which will result in overcompression. If no helium release device is provided, the watch will generally lose its crystal which is not devised to withstand internal pressure.

However, there are applications in which this virtually perfect impermeability is a drawback. Indeed, in altimeter type applications or where a zinc air power supply is used, an air flow must be allowed between the housing of the portable object, in which the altimeter device and/or the zinc air power supply are arranged, and the exterior of the portable object.

While such objects exist, it is necessary to maintain the impermeability of said device.

It is also known to use membranes made of Gore-Tex® material. This material is known to be porous, i.e. it has a multitude of pores of such small size that it allows gases to pass through while blocking liquids.

However, this material has a drawback. Indeed, a membrane made of Gore-Tex® type material will only be waterproof to a limited depth of 15 to 40 m. Beyond this depth, water bubbles shrink under pressure which then allows water to pass through the pores making the material permeable.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to overcome the drawbacks of the prior art by providing a portable object including a semi-impermeable device, i.e. which allows gases to pass through but not liquids and which can be used at depths of more than 100 m.

To this end, the invention concerns a portable object comprising a case forming a housing, inside which is arranged a device that requires air to operate, said portable object further comprising a closure device comprising at least one permeable element, said closure device being arranged to provide impermeability to liquids while allowing the atmosphere inside the housing to communicate with the external atmosphere, characterized in that said case is composed of a first part and a second part attached to each other, the closure device further comprising a gasket made of a semi-permeable material.

In an advantageous embodiment, said gasket is made of silicon.

The invention also concerns a portable object comprising a case forming a housing inside which is arranged a device that requires air to operate, said portable object further comprising a closure device comprising at least one permeable element, said closure device being arranged to provide impermeability to liquids while allowing the atmosphere inside the housing to communicate with the external atmosphere, characterized in that said case has a through opening, the closure device comprising a semi-permeable membrane located opposite said opening, said semi-permeable membrane comprising a porous support on which is fixed a film that is permeable to gases and impermeable to liquids, the thickness of said film making it possible to change the time constant for equilibration of gases between the interior and exterior of the portable object.

In an advantageous embodiment, the film is a polymer.

In another advantageous embodiment, said case comprises, on its inner wall, a recess inside which the closure device is placed, said recess having a lateral wall comprising a groove extending along said lateral wall and used for holding said membrane, said membrane also being held pressed onto the inner wall by holding means composed of a cover and said closure device further comprises a gasket inserted between said cover and the membrane.

The invention finally concerns a portable object comprising a case forming a housing inside which is arranged a device that requires air to operate, said portable object further comprising a closure device comprising at least one permeable element, said closure device being arranged to provide impermeability to liquids while allowing the atmosphere inside the housing to communicate with the external atmosphere, characterized in that said case comprises a recess in which a through opening is made, said recess being closed by said closure device and in that said closure device comprises a permeable module mounted to move such that, in a gaseous environment, the permeable module is in a rest position allowing gases to penetrate said case opening through said permeable module and such that, in a liquid environment, the permeable module is in an operating position in which gases and liquids are blocked.

In a first advantageous embodiment, said permeable module comprises a tubular support at the end of which is fixed a membrane, the support being mounted, in a suspended manner, by means of a flexible gasket.

In a second advantageous embodiment, said membrane is selected to be permeable.

In a third advantageous embodiment, the closure device is arranged on an external wall of said portable object.

In a fourth advantageous embodiment, the closure device is arranged on an internal wall of said portable object.

In a fifth advantageous embodiment, said device requiring air to operate is a zinc air battery.

In a sixth advantageous embodiment, said device requiring air to operate is an altimeter.

In a seventh advantageous embodiment, the closure device renders said portable object impermeable to a depth of at least 100 m.

DETAILED DESCRIPTION

A portable object1according to the present invention is represented inFIGS. 1 to 5. This portable object1may take the form of a timepiece or a mobile telephone or a smart phone or a touch tablet.

Portable object1includes a case2forming a housing inside which is arranged a device4that requires air to operate.

In a first embodiment seen inFIGS. 1 to 3c, device4requiring air to operate is an electric battery6. This battery is, for example, of the zinc air type, i.e. it uses oxygen from the air to oxidise the metal of which it is formed and to supply electricity. The zinc air battery must be supplied with air otherwise it will dry out and lose performance.

This electric battery is used to operate an electronic system8associated with display means10. Electronic system8may also comprise control means and/or communication means.

Advantageously according to the invention, the portable object is also provided with a closure device12enabling the battery to be supplied with air while ensuring that the portable object is impermeable to liquids, this impermeability being able to achieve depths of more than 100 meters.

In a first variant seen inFIG. 1, case2of the portable object comprises at least a first part2aand a second part2bsuch as a case middle2aclosed by a back cover2b. Display means10, such as a digital screen or a dial/crystal assembly, may form a third part. Closure device12then comprises a gasket14placed between the first part2aand second part2b.

This gasket14is selected to be made of a semi-permeable material, i.e. a material that allows gas to pass through but blocks liquids. This material may be a polymer. Indeed, gases pass through dense polymer films by a process of “dissolution-diffusion”. The application of a gas pressure gradient (drive force) between the upstream face (under overpressure) and downstream face (under depression) of the membrane causes the following three successive phenomena:

Absorption of gas at the upstream surface,

Molecular dissolution and diffusion of the gas in the material

Desorption of the gas from the downstream surface.

One material used for this type of application is silicone. At ambient temperature, silicones exhibit, on average, a gas permeability that is 10 times greater than that of natural rubber, but become closer around 100 to 150° C.

This configuration therefore associates the small gap between first part2aand second part2b, and gasket14made of semi-permeable material, to allow a small quantity of air to pass from the exterior of the portable object to the interior. In this case, the time constant necessary to balance the gases between the interior and exterior of the portable object is on the order of several days. It is thus understood that this variant can be used for the operation of a portable object1using little electricity and thus requiring little air, such as, for example, a watch with three hands displaying only the time, which uses a few microamperes.

In a second variant seen inFIG. 2, case2of the portable object is arranged to include an opening16allowing a large volume of air to pass through, having, for example, a diameter of 5 mm, and located in the case back. In such case, closure device12comprises a high density membrane18placed inside the case. To this end, the inner wall of the case comprises, at the opening, a recess20for high-density membrane18. This recess has a lateral wall22. This lateral wall has a groove24extending along the lateral wall. The groove is used for holding said high-density membrane. The high-density membrane is held by holding means26composed of a gasket28and a cover30. Cover30is attached to the inner case wall so that gasket28is inserted between said cover30and high-density membrane18.

The high-density membrane18, also called a “supported membrane” or “composite membrane” is composed of a film18a, made of a polymer material that retains water 100% but is permeable to gases, like all plastics.

Thus, in order to use film18a, it must be deposited on a support18bwhich is also a membrane but much thicker. This support membrane18bis porous so that air can pass through; the only function of support membrane18bis mechanical, since its only object is to act as a support for polymer film18a. For example, a support membrane made of Gore-Tex® may be used. Consequently, the drawback of Gore-Tex® membranes is overcome, since film18awill ensure impermeability to liquids even at great depths.

To regulate the air flow passing through high-density membrane18, the parameter to act on is the thickness of film18a. The thinner film18a, the greater the flow will be, but also the more fragile film18awill be and vice versa.

Typically, to have a time constant for equilibration of gases between the interior and exterior of the portable object on the order of a minute, the thickness of film18amust be on the order of 10 micrometers.

This feature enables high-density membrane18to be used in a portable object having a relatively high electrical energy consuming electronic system, around 50 milliamperes, this power consumption may be due to the use of digital sensors or screens or Bluetooth® type communication means.

In a third variant seen inFIG. 3a, case2of the portable object comprises, on its external wall, a recess32inside which is arranged closure device12. An opening34is arranged in recess32. Closure device12takes the form of a permeable module36mounted to be movable.

Indeed, closure device12, i.e. permeable module36, comprises a support38taking the form of an open tubular piece, at the end of which is attached a membrane40. Support38is mounted in a suspended manner by means of a flexible gasket42. In the case of a circular tubular support38, flexible gasket42is also circular. The inner edge42aof flexible gasket42is attached to tubular piece38, whereas the outer edge42bis attached to lateral wall32aof recess32.

Membrane40closing one of the ends of tubular support38is located at the end of the tubular support facing the recess and is made of a permeable material. One material used is Gore-Tex® which has the feature of allowing gases to pass through and retaining liquids up to a pressure of 1 bar.

Closure device12operates as follows. When the portable object is in the open air, air passes through permeable membrane40and penetrates opening34of case2so that battery6can provide electrical energy. Permeable module36is then in a first position, or rest position, in which no external stress is applied on flexible gasket42.

When a portable object1is immersed, water then exerts pressure and therefore a mechanical force on membrane40of tubular support38. This mechanical force on membrane40causes a deformation of flexible gasket42. The deformation of flexible gasket42permits a movement of permeable module36and therefore of tubular support38, so that it moves and enters into contact with the bottom of the recess, i.e. into a second position or operating position. In such case, membrane40enters into contact with bottom32b. This contact between permeable membrane40and bottom32bof recess32, i.e. the case, results in closure of the passage, even under a high pressure of 10 bars.

The advantage of such a closure device is that it can provide a time constant for equilibrium of the gases between the interior and exterior of the portable object on the order of a second, i.e. the flow of air is large while still ensuring the impermeability of the portable object.

In a first variant of this third embodiment, bottom32bof the recess is provided with a second gasket44called a flat gasket. Flat gasket44is used to improve the blocking of water ingress. Indeed, this flat gasket44is made of a plastic type material, such as a polymer or rubber. The function of flat gasket44is to completely block the pores of the membrane.

In a second variant of this third embodiment, an absorber such as, for example, silica gel is used in addition to the membrane. The absorber is used to reduce the importance of relative humidity variations in a watch. The quantity of absorber can be determined according to the volume of the watch so that the permeability to humidity of the latter is equivalent to that obtained with conventional gaskets.

In a third variant of this third embodiment, closure device12is arranged to be invisible. To this end, recess32seen inFIG. 3bis closed by a cap39, this cap being pierced with at least one aperture39ballowing water to penetrate to act on permeable module36. This variant advantageously allows closure device12to be protected against any shocks that may occur. To ensure the impermeability of said cap, a gasket39bis used.

Of course, it is possible for recess32to be arranged on the inner wall of case2. Case2is thus arranged to have on its inner wall a recess32′, provided with a lateral wall32a′on which is arranged movably mounted permeable module36, as seen inFIG. 3c. Holes2aare arranged to allow air or a liquid to be in contact with permeable module36.

Indeed, closure device12, i.e. permeable module36, comprises a support38taking the form of an open tubular piece, at the end of which is attached a membrane40. Support38is mounted in a suspended manner by means of a flexible gasket42. The inner edge42aof flexible gasket42is attached to tubular piece38, whereas the outer edge42bis attached to lateral wall32a′of recess32′.

Recess32′ is then closed by a cap39′ mounted on the inner face of case2, the cap permitting cooperation with membrane40so that, when portable object1is immersed, water will then exert pressure and thus a mechanical force on membrane40causing a deformation of flexible gasket42. This deformation of flexible gasket42allows permeable module36to move and enter into contact with said cap acting as the bottom of the recess.

Cap39′ may be secured by a screw thread directly incorporated in said cap39′ or by screws and a gasket39a′.

In a second advantageous embodiment seen inFIGS. 4 to 5c, the device requiring air for operation4is an altimeter7. Altimeter7may be mechanical or electronic and includes a deformable membrane7a.

In the case of a mechanical altimeter, the latter includes a transmission mechanism7b. Membrane7ais capable of deforming mechanically under the effect of external pressure acting in that case on transmission device7b. Transmission mechanism7bthus transfers said movement of deformation from membrane7a, representing pressure, to display means10which display the altitude value.

In the case of an electronic altimeter (not represented), the latter includes a transmission circuit7c. Membrane7ais capable of deforming mechanically under the effect of external pressure acting in that case on transmission circuit7c. Transmission circuit7cis an interface allowing the deformation of the membrane to be converted into an electrical signal. This electrical signal is processed so that display means10can use the signal to display altitude information.

Advantageously according to the invention, portable object1is also provided with a closure device12allowing air to penetrate the housing of the portable object to interact with membrane7aof the altimeter without water penetrating.

In a first variant seen inFIG. 4, case2of the portable object is arranged to include an opening116allowing a large volume of air to pass through, having, for example, a diameter of 5 mm, and located in the case back. In such case, closure device12comprises a high density membrane18placed inside case2. To this end, the inner wall of the case comprises, at the opening, a recess120for high-density membrane118. This recess120has a lateral wall122. Lateral wall122has a groove124extending along lateral wall122. Groove124is used for holding said high-density membrane118. High-density membrane118is held by holding means126composed of a gasket128and a cover130. Cover130is attached to the inner case wall so that gasket128is inserted between said cover130and high-density membrane118.

The high-density membrane118, also called a “supported membrane” or “composite membrane” is composed of a film118a, made of a polymer material that retains water 100% but is permeable to gases, like all plastics.

Thus, in order to use film118a, it must be deposited on a support118bwhich is also a membrane but much thicker. This support membrane118bis porous so that air can pass through; the only function of support membrane118bis mechanical, since its only object is to act as a support for polymer film118a. For example, a support membrane118bmade of Gore-Tex® may be used.

To regulate the air flow passing through high-density membrane118, the parameter to act on is the thickness of film118a. The thinner film118a, the greater the flow will be, but also the more fragile film118awill be and vice versa.

Typically, to have a time constant for equilibration of gases between the interior and exterior of the portable object on the order of a minute, the thickness of film118amust be on the order of 10 micrometers.

This feature allows high density membrane118to be used for an altimeter since the equilibration time is relatively short. A short equilibration time allows the user to quickly obtain the required altitude value.

In a second variant seen inFIG. 5a, case2of the portable object comprises, on its external wall, a recess132inside which is arranged closure device12and an opening arranged in the recess.

Indeed, closure device12, i.e. permeable module136, comprises a support138taking the form of an open tubular piece, at the end of which is attached a membrane140. Support138is mounted in a suspended manner by means of a flexible gasket142. In the case of a circular tubular support138, flexible gasket142is also circular. The inner edge142aof flexible gasket142is attached to tubular piece138, whereas the outer edge142bis attached to lateral wall132aof recess132.

Membrane140closing one of the ends of tubular support38is located at the end of the tubular support facing the recess and is made of a permeable material. One material used is Gore-Tex® which has the feature of allowing gases to pass through and retaining liquids up to a pressure of 1 bar.

Closure device12operates as follows. When the portable object is in the open air, air passes through permeable membrane140and penetrates opening134of case2so that the altitude measurement can be made by membrane7a. Permeable module136is then in a first position, or rest position, in which no external stress is applied on flexible gasket142.

When a portable object1is immersed, water then exerts pressure and therefore a mechanical force on membrane140of tubular support138. This mechanical force on membrane140causes a deformation of flexible gasket142. The deformation of flexible gasket142permits a movement of permeable module136and therefore of tubular support38, so that the latter moves and enters into contact with the bottom of the recess, i.e. into a second position or operating position. In such case, membrane140enters into contact with bottom132b. This contact between permeable membrane140and bottom132bof recess132, i.e. the case, results in closure of the passage, even under a high pressure of 10 bars.

The advantage of such a closure device is that it can provide a time constant for equilibration of the gases between the interior and exterior of the portable object on the order of a second, i.e. the flow of air is large while still ensuring the impermeability of the portable object. Consequently, the altitude measurement is fast so that the user does not have to wait long to have the exact measured altitude.

In a first variant of this second embodiment, bottom132aof recess132is provided with a second gasket144called a flat gasket. Flat gasket144is used to improve the blocking of water ingress. Indeed, this flat gasket144is made of a plastic type material, such as a polymer or rubber. The function of flat gasket144is to completely block the pores of the membrane.

In a second variant of this second embodiment, an absorber such as, for example, silica gel is used in addition to the membrane. The absorber is used to reduce the importance of relative humidity variations in a watch. The quantity of absorber can be determined according to the volume of the watch so that the permeability to humidity of the latter is equivalent to that obtained with conventional gaskets.

In a third variant of this second embodiment, closure device12is arranged to be invisible. To this end, recess132seen inFIG. 5bis closed by a cap139, this cap being pierced with at least one aperture139ballowing water to penetrate to act on permeable module136. This variant advantageously allows closure device12to be protected against any shocks that may occur. To ensure the impermeability of said cap, a gasket139bis used.

Of course, it is possible for the recess to be arranged on the inner wall of case2. Case2is thus arranged to have on its inner wall a recess132′, provided with a lateral wall132a′on which is arranged movably mounted permeable module136, as seen inFIG. 5c. Holes2aare arranged to allow air or a liquid to be in contact with permeable module136.

Indeed, closure device12, i.e. permeable module136, comprises a support138taking the form of an open tubular piece, at the end of which is attached a membrane140. Support138is mounted in a suspended manner by means of a flexible gasket142. The inner edge142aof flexible gasket142is attached to tubular piece138, whereas the outer edge142bis attached to lateral wall132a′of recess132′.

Recess132′ is then closed by a cap139′ mounted on the inner face of case2, the cap permitting cooperation with membrane140so that, when portable object1is immersed, water will then exert pressure and thus a mechanical force on membrane140causing a deformation of flexible gasket142. This deformation of flexible gasket142allows permeable module136to move and enter into contact with said cap acting as the bottom of the recess.

Cap139′ may be secured by a screw thread directly incorporated in said cap139′ or by screws and a gasket139a′.

It will be clear that various alterations and/or improvements evident to those skilled in the art may be made to the various embodiments of the invention described in this description without departing from the scope of the invention.