Exhalation valve assembly for a body-wearable protective device

Description

[0001] This invention relates generally to a facial breathing mask incorporating an exhalation valve, and a removable cover for such an exhalation valve.

[0002] Many different types of facial breathing mask are known for protecting a wearer against breathing in dangerous fumes, preventing cross-infection and the like. One such known mask comprises a resiliently flexible, e.g. rubberised, mask body configured to fit over a user's nose and mouth, in use, and including a generally central opening, in which is provided an opening defining an airway and having provided therein a set of radial support members, over which is provided a flexible diaphragm configured to define a one-way exhalation valve. The mask body is further provided with a pair of openings at opposing sides or 'cheek' portions thereof, for receiving respective filter cartridges. In use, when a user inhales, the diaphragm seals the central opening and the inhaled air is forced to pass through the filter cartridges to the user's nose and mouth. When the user exhales, the force of the airflow causes the edges of the diaphragm to flex away from the central opening support members, allowing exhaled air to pass therethrough out of the mask.

[0003] It is necessary to provide a cover on the protective device, over the diaphragm forming the exhalation valve, to prevent it from becoming damaged and / or clogged up with debris, for example. However, it is equally important to allow periodic access to and removal of the diaphragm such that it, and the corresponding exhalation airway components, can be cleaned and then reassembled for further use. Thus, a removable cover is generally provided for this purpose.

[0004] In prior art devices, such a removable cover is generally configured to clip on and off the face mask (in a linear direction). However, in view of the flexible nature of the mask body, and the degree of deformation that may occur when a user is securing the mask over their face, the valve cover can, relatively easily, be dislodged and inadvertently removed.

[0005] US2929376 discloses a regulator in a breathing apparatus comprising a casing open at one end, said casing forming a chamber with an inlet for breathable gas; valve means at said inlet urged in the closing direction by the pressure of said breathable gas and disposed to control the flow of breathable gas into said chamber; a diaphragm closing the open end of said casing and being exposed at one side to the pressure of gas in said chamber and at the other side to the pressure of a surrounding medium, said diaphragm being movable in - response to differentials in such pressures; means operative when said diaphragm moves inwardly relative to. said casing, to open said valve means and admit breathable gas; a mouthpiece formed on the end of the casing opposite said diaphragm through which said breathable gas may be inhaled and spent gas exhaled; -and an exhalation valve carried by and-closing an opening in said diaphragm, said exhalation valve being movable toward open, position when the, pressure in said chamber exceeds the pressure of the surrounding medium by a predetermined amount.

[0006] GB530289 discloses an exhalation valve for gas masks, particularly for horses comprises a screw-threaded pin arranged centrally of a bar bridging the annular valve seat and carrying the rubber or like valve disc, a nut-forming sieve being screwed on the pin from the interior, so as to clamp the beaded edge of the opening in the mask between the sieve and the valve seat.

[0007] WO2006118599 discloses a sealing device for positive pressure testing is attached to a respirator face mask and includes an outer frame integrally joined to a movable cap by a flexible link that biases the cap in an open position for the operational use of the face mask against a manually applied force to move the cap to a sealed position for the positive pressure testing to assure the proper fit of the face mask on the wearer. The method for positive pressure testing includes flexibly moving the sealing device from the open position to the sealing position such that the sealing surface of the cap seals the exhalation valve assembly closed. The wearer then exhales into the mask to test the seal of the mask. When the test is completed, the sealing device is released, and the inherent biasing force moves the cap from the sealing position to the open position.

[0008] WO2006037000 discloses a respirator exhalation unit comprises a negative pressure valve and a selectively actuable positive pressure valve assembly. The position of the positive pressure valve assembly is selectively adjustable to convert the exhalation unit for use in multiple operating modes, such as a negative pressure mode, a powered air mode, and a self-contained breathing apparatus mode (SCBA). Additionally, a closed-circuit breathing apparatus (CCBA) adapter assembly can be attached to the exhalation unit for conversion to a CCBA operating mode. Further, the negative pressure valve divides the interior of the exhalation unit into two chambers, one of which functions as a dead space that protects the user from exposure to any harmful contaminants at the end of exhalation.

[0009] US4850346 discloses breathing equipment, e.g., a half mask-type respirator. A mask is provided with three ports of common dimension in any one of which inhalation or exhalation fittings housing inhalation or exhalation valves may be mounted. Disclosed are chemical and mechanical filtration cartridges usable alternatively or in combination. Disposable chemical filtration cartridges having novel lock and seal structure are disclosed. Bayonet-type couplings for coupling the filter housings to the inhalation respiratory fittings and an audible device to indicate that the filter housings are properly coupled are disclosed. The respirator valve is a thin umbrella-shaped disk valve having a multiplicity of radiating ribs which biases the valve to the closed position.

[0010] It would, therefore, be desirable to provide a wearable protective device including an exhalation valve, in which a removable cover is provided which addresses this issue.

[0011] In accordance with the present invention, there is provided a respiratory breathing mask including an exhalation valve assembly, comprising a valve support for receiving a valve member; a valve cover comprising an open-ended receptacle having side walls defining an enclosure and a cover at one end thereof; wherein the valve cover comprises two outer cover sections, a first, raised cover section and a second, lower cover section, the first and second cover sections defining a vertical through-hole therebetween; and a releasable mounting mechanism for releasably mounting the valve cover to the valve support so as to substantially cover the valve member, the mounting mechanism comprising a bayonet locking mechanism having a first part located on the valve support and a second part located on the valve cover, the first and second part being configured to engage in a locked configuration when the valve cover is rotated relative to the valve support from an unlocked configuration.

[0012] The mounting mechanism comprises at least three spaced apart locking members on the valve support, each locking member defining a locking edge, and at least three spaced apart openings in the valve cover, the location of the openings corresponding substantially to the location on the valve support of the locking members when the valve cover is located thereon so as to substantially cover the valve member such that the locking edge of each locking member engages with a locking edge of a respective opening in the valve cover.

[0013] The valve cover openings extend over at least 50% of the axial length of the side walls of the open-ended receptacle having side walls defining the enclosure.

[0014] The first part of the bayonet locking mechanism is provided on each locking edge of the locking member and the second part of the bayonet locking mechanism is provided on each locking edge of the valve cover openings.

[0015] The first part of the bayonet locking mechanism comprises a notch located along the length of the locking edge of the locking members, and the second part of the bayonet locking mechanism comprises a projection located along each length of the locking edge of the openings in the valve cover.

[0016] The locking edge on at least one side of the notch has a substantially convex curved profile along the direction of travel of the valve cover relative to the valve support during rotation thereof from the unlocked configuration to the locked configuration.

[0017] The locking members are located adjacent substantially diametrically opposing edges of the valve support and the valve cover openings are located adjacent corresponding substantially diametrically opposing edges of the valve cover.

[0018] An inner edge of each notch is stepped or relatively steeply tapered, and the locking edge on at least one side of the notch is provided with a relatively shallowly tapered profile.

[0019] The valve cover openings may extend over between 50 and 75% of the axial length of the side walls. In an alternative exemplary embodiment, the valve cover openings may extend over more than 75% of the axial length of the side walls.

[0020] These and other aspects of the present invention will become apparent from the following specific description, in which embodiments of the present invention are described, by way of examples only, and with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an exhalation valve and cover according to an exemplary embodiment of the present invention; Figure 2 is an exploded perspective view of a respiratory face mask incorporating the exhalation valve and cover of Figure 1; Figure 3 is a schematic front view of the respiratory face mask of Figure 2, in its fully assembled configuration, but with the cover removed; Figure 3a is a schematic side view of the respiratory face mask of Figure 3; Figure 3b is a schematic partial front view of a portion of the locking mechanism used in the exhalation valve of Figure 1; Figure 3c is a schematic partial side view of a portion of the locking mechanism used in the exhalation valve of Figure 1; Figure 4 is a front view of the respiratory face mask of Figure 2 in its fully assembled configuration, including the cover in its unlocked configuration; Figure 5 is a front view of the respiratory face mask of Figure 4, with the cover in its locked configuration; Figure 6 is a partial side view of an exhalation valve according to an exemplary embodiment of the present invention, with the cover in its unlocked configuration; and Figure 7 is a partial side view of the exhalation valve of Figure 6, with the cover in its locked configuration.

[0021] Referring to Figure 2 of the drawings, a respiratory mask including an exhalation valve according to an exemplary embodiment of the present invention comprises a rubberised mask body 6, a rigid inner body 1, a strap ring 2, a diaphragm 3 and an exhalation valve cage (or cover) 4. Each of these elements fits together to form a complete respiratory mask having side openings 36a for receiving a respective disposable filter cartridge (not shown). In its assembled form, the inner body 1 is sealed and affixed within the mask body 6, but the strap ring 2, diaphragm 3 and valve cover 4 can all be removed and re-attached as required.

[0022] Referring to Figure 3 of the drawings, there is provided a generally central, substantially circular opening 6a on a front face 6b of the mask body 6, the mask body 6 being formed of an elastically deformable material, e.g. rubber or the like. The inner body 1 defines a substantially rigid plate 1a defining a generally central, substantially circular collar 1b that projects outwardly from the opening 6a in the mask body 6. The collar 1b is spanned by six substantially equi-angularly spaced support struts 8 which extend, substantially radially, from a generally central pin hole 9. A pair of openings are provided on opposing sides of the mask body 6 and configured to removably receive respective disposable filter cartridges of any known configuration.

[0023] Referring back to Figure 2 of the drawings, a flexible diaphragm 3 is provided over the opening defined by the collar 1b and is supported by the struts 8, and secured by a rearwardly projecting pin which is integrally formed with the diaphragm 3 and configured to be received within the pin hole 9.

[0024] Referring additionally to Figures 3a to 3c of the drawings, three generally L-shaped locking members 110 are integrally formed with the inner body and located adjacent to the circumferential edge of the collar 1b. Each locking member 110 comprises an elongate leg portion 110a and a shorter flange portion 110b at its distal end which extends substantially orthogonally to the longitudinal axis of the leg portion 110a to create the substantially L-shaped locking member 110. Each locking member 110 extends, from the proximal end of the respective leg portion 110a, outwardly and at a slight angle to the front face of rigid plate 1a, and the flange portion of 110b of each locking member 110 extends radially outward relative to the opening 6a and substantially parallel to the principal plane of the rigid plate 1a, as shown most clearly in Figure 3b of the drawings.

[0025] As shown particularly in Figure 3c of the drawings, the free edge of the flange portion 110b of each locking member 110 is profiled to include a notch 110c at an intermediate distance along its lateral length. The notch 110c is defined by stepped or sharply tapered inner edges and a curved and convex profile leading to a shallower taper at a location laterally distant from the notch 110c.

[0026] Referring back to Figure 2 of the drawings, the strap ring 2 defines a generally central recess 2a defining an opening 2b, that accommodates the collar 1b of the inner body 1, over which the diaphragm 3 is mounted, when the respiratory mask is fully assembled for use. The opening 2b is framed by a substantially circular border 2c defining the inner circumferential edge of the recess 2a. The valve cage or cover 4 comprises a generally cylindrical, substantially rigid shell 4a, which may be transparent and formed of, for example, plastics material. The cylindrical shell is circumferentially dimensioned to fit within the recess 2a of the strap ring 2 when the respiratory mask is fully assembled for use. The shell is provided with an outer cover having a first, raised convex portion 4b and a second, lower substantially flat portion 4c, defining a generally central upper opening 4d therebetween. A vertical support member 4e is provided vertically across the opening 4d between the raised and lower cover portions 4b, 4c. The side edges of the shell 4a are provided with cut-away portions in the form of substantially rectangular openings 20a, 20b, 20c which extend laterally from the outer edge of a respective cover portion and a location close to the opposite longitudinal edge of the shell 4a, i.e. close to the circumferential edge of the strap ring recess 2a when the respiratory mask is fully assembled for use, and spanning almost the entire length of the cylindrical shell portion 4a of the cover.

[0027] The lower edge of each of the rectangular openings 20a, 20b, 20c is provided with a respective tooth or rib 13 at a location that is off-centre along its length.

[0028] It will be appreciated from, for example, Figures 1, 4, 6 and 7 of the drawings, that the relative locations of the openings 20a, 20b, 20c in the shell of the valve cage or cover 4 correspond generally to the relative locations of the locking members 110 provided on the inner body 1 and the circumference of the shell 4a, at least at the location of the openings 20a, 20b, 20c is such that the locking members 110 can be accommodated within the shell at these respective locations when the respiratory mask is fully assembled for use.

[0029] Further openings 22 may be provided at the circumferential locations around the side of the shell 4a, as required, to further decrease breathing resistance, as will be discussed in more detail later.

[0030] In use, the valve cage 4 can be placed over the exhalation valve of the respiratory mask (outwardly defined by the diaphragm 3), and twisted relative to the locking members 110 to lock the valve cage (in the form of a cover) over the exhalation valve assembly. The locking mechanism is in the form of a bayonet locking mechanism, with the notch 110c in each of the flange portions 110b of respective locking members 110 forming the female receptor of the locking mechanism and the tooth or rib 13 on the inner edge of each of the openings 20a, 20b, 20c forming the male part of the mechanism.

[0031] Thus, referring to Figures 6 and 7 of the drawings, each opening 20a, 20b, 20c has a raised tooth 13 on the innermost edge of the aperture relative to the main body 6 of the respiratory mask, when in a fully assembled configuration for use. The raised tooth 13 of each opening 20a, 20b, 20c corresponds to a notch 110c in the flange portion 110b of each locking member 110.

[0032] Referring to Figure 6 of the drawings, when the exhalation valve is in the unlocked configuration, the three locking members 110 are loosely received within the recesses defined by the rectangular openings 20a, 20b, 20c of the valve cage 4. Therefore, the valve cage 4 can be lifted from the assembly, releasing the strap ring 2 and enabling the exhalation valve to be dismantled. This may, for example, be necessary in order to remove and clean the diaphragm 3, a task which generally needs to be performed on a regular basis.

[0033] Conversion of the exhalation valve from the unlocked configuration to the locked configuration requires a substantially 45° rotation of the valve cage, forcing the inner edge of the openings 20a, 20b, 20c along the convex and tapered edge of respective flange portions 110b of the locking members 110 until each tooth 13 reaches a respective notch 110c and the stepped, opposite edge of the notch 110c prevents further rotation of the valve cage 4 relative to the inner body without the application of a much larger force.

[0034] Referring to Figure 7 of the drawings, when the exhalation valve is in the locked configuration each raised tooth 13 sits inside each notch 110c in each respective flange portion 110b of the locking members 110, preventing the valve cage 4 from rotating and subsequently lifting from the assembly. The shallow taper and curved profile of the leading inner edge of each opening 20a, 20b, 20c (in the direction of travel of the cover when being rotated from the unlocked to the locked configuration) allows the locking action to be effected with relatively little force. However, the steeper, stepped edges immediately adjacent the each notch 110c means that a much greater force is required to unlock the valve cage 4 to remove it, thereby minimising its accidental removal, in use.

[0035] The overall configuration of the valve cage locking mechanism, and the use of the large side openings as part of the locking mechanism itself, enables the cover to be provided with a relatively large open area, and breathing resistance is thereby minimised.

[0036] In some exemplary embodiments of the invention, and as can be seen in Figure 3 of the drawings, two of the locking members 110, and therefore two of the flange portions 110b are of the same dimensions, whilst a third locking member 110, and therefore the respective third flange portion 110b, is of a different, smaller, dimension. This ensures that the valve cage 4 cannot be assembled onto the respiratory mask incorrectly and the corresponding openings 20a, 20b, 20c will only engage with the flange portions 110b in a single, specific orientation. There are may also be markings engraved on the surface of the strap ring 2, corresponding to an indent in the valve cage 4, directing the user to the correct positions for the valve cage 4 when in the unlocked and locked configurations.

[0037] It will be apparent to a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined in the appended claims.

Claims

1. A respiratory breathing mask including an exhalation valve assembly, comprising: a valve support (1) for receiving a valve member (3); a valve cover (4) comprising: an open-ended receptacle (4a) having side walls defining an enclosure and a cover (4b, 4c) at one end thereof; wherein the valve cover comprises two outer cover sections, a first, raised cover section (4b) and a second, lower cover section (4c), the first and second cover sections (4b, 4c) defining a vertical through-hole (4d) therebetween; and a releasable mounting mechanism for releasably mounting the valve cover (4) to the valve support (1) so as to substantially cover the valve member (3), the mounting mechanism comprising a bayonet locking mechanism having a first part (110) located on the valve support (1) and a second part located on the valve cover (4), the first and second part being configured to engage in a locked configuration when the valve cover is rotated relative to the valve support from an unlocked configuration; wherein the mounting mechanism comprises: at least three spaced apart locking members (110) on the valve support (1), each locking member (110) defining a locking edge (110b), and at least three spaced apart openings (20a, 20b, 20c) in the valve cover (4), the location of the openings (20a, 20b, 20c) corresponding substantially to the location on the valve support (1) of the locking members (100) when the valve cover (4) is located thereon so as to substantially cover the valve member (3) such that the locking edge (110b) of each locking member (110) engages with a locking edge of a respective opening (20a, 20b, 20c) in the valve cover (4), wherein the valve cover openings (20a, 20b, 20c) extend over at least 50% of the axial length of the side walls of the open-ended receptacle (4a) having side walls defining the enclosure; the first part (110c) of the bayonet locking mechanism being provided on each locking member locking edge (110b) and the second part (13) of the bayonet locking mechanism being provided on each valve cover opening locking edge; wherein the first part of the bayonet locking mechanism comprises a notch (110c) located along the length of the locking edge (110b) of the locking members (110), and the second part of the bayonet locking mechanism comprises a projection (13) located along each length of the locking edge of the openings (20a, 20b, 20c) in the valve cover (4); wherein the locking edge (110b) on at least one side of the notch (110c) has a substantially convex curved profile along the direction of travel of the valve cover (4) relative to the valve support (1) during rotation thereof from the unlocked configuration to the locked configuration; wherein the locking members (110) are located adjacent substantially diametrically opposing edges of the valve support (1) and the valve cover openings (20a, 20b, 20c) are located adjacent corresponding substantially diametrically opposing edges of the valve cover (4); and wherein an inner edge of each notch (110c) is stepped or relatively steeply tapered, and the locking edge on at least one side of the notch (110c) is provided with a relatively shallowly tapered profile.

2. A respiratory breathing mask according to claim 1, wherein the valve cover openings (20a, 20b, 20c) extend over between 50 and 75% of the axial length of the side walls.

3. A respiratory breathing mask according to claim 1, wherein the valve cover openings (20a, 20b, 20c) extend over more than 75% of the axial length of said side walls.