Abstract:
A respiratory mask and service module combination for pressure breathing. The respiratory mask has a hardshell member that extends along the contour of the face toward the peripheral edge of the mask and has a central portion forming a canopy. An inhalation/exhalation valve assembly having two breathing conduits and integrally formed so as to provide communication between the conduits. The assembly mounts externally to the mask such that the valves are capable of being sealed along the outer surface of the respiratory mask. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to limit the scope or meaning of the claims. 37 C.F.R. 1.72(b).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Applicant hereby claims priority based on U.S. Provisional Application No. 60/197,762 filed Apr. 17, 2000, entitled “Respiratory Mask With a Modular Inhalation/Exhalation Valve Assembly” which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to respiratory masks and service modules suitable for use in pressure breathing and other applications. 
     BACKGROUND OF THE INVENTION 
     High performance, high altitude flying typically poses several challenges for masks for pressure breathing. First, high mask pressures make it relatively difficult to hold the mask on the face with minimal leakage. Second, the “G” forces combined with the harnessing and mask pressures tend to cause discomfort for the user. Third, “G” forces sometimes cause the mask to lose proper position and to migrate around the face. 
     Because of the environment that the mask assembly is subjected to, namely the pressure differential in high altitude applications and the forces associated with High “G” force applications, it is desirable to minimize the volume of the internal breathing cavity. A larger breathing gas cavity where pressure is higher than ambient would create greater forces urging the mask away from the face of the user thus requiring tighter restraints to keep the mask on the face. 
     Accordingly there is a need for an oro-nasal mask that minimizes the surface area “footprint” of the mask internal breathing cavity on the face. 
     With any pressure breathing mask, some force needs to be exerted on the face to counteract pressure forces and for harnessing. It is important to exert this force in a fashion so that it is not localized or causing pressure points on isolated areas such as the bridge of the nose. 
     Also, because varying “G” loads and directions will magnify any mask weight and attempt to pull it around the face there is a need for a mask design that is structurally supported on the face so as to be resistant to being pulled around the face. 
     Further, in order to provide a proper seal for different face sizes and face shapes, it is often desirable to provide an arrangement so that breathing conduits or the like can be easily and quickly combined with more than one size mask. 
     In addition to the high altitude, high performance setting, the modular design would also be important to many other types of masks including, but not limited to, full facepiece masks, standard half facepiece masks, half facepiece masks with detachable goggles, or the like. 
     SUMMARY OF THE INVENTION 
     The present invention meets the above-described need by providing a respiratory mask and service module combination. 
     The mask provides a modular arrangement such that the service module can be used with many different sized mask assemblies. 
     The service module is described herein in connection with a mask assembly suitable for high “G” force applications. However, as it will be apparent to those of ordinary skill in the art, the service module could also be integrated into modular designs for other types of masks including, but not limited to, full facepiece masks, standard half facepiece masks, half facepiece masks with detachable goggles, or the like. 
     Also, in order to provide a proper seal for different face sizes and face shapes, it is often desirable to provide more than one size mask. The present invention provides for interchanging different mask assemblies with a single service module. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which: 
     FIG. 1 is a perspective view of the respiratory mask and inhalation/exhalation valve assembly of the present invention; 
     FIG. 2 is a front elevational view of the respiratory mask and inhalation/exhalation valve assembly of the present invention; 
     FIG. 3 is a perspective view of the half facepiece mask of the present invention with the inhalation/exhalation valve assembly removed; 
     FIG. 4 is a front elevation of the hardshell subassembly for the half facepiece mask of the present invention; 
     FIG. 5 is a perspective view of the hardshell subassembly for the half facepiece mask of the present invention; 
     FIG. 6 is a perspective view of the inside of the half facepiece respiratory mask; 
     FIG. 7 is a sectional side view of the mask and inhalation/exhalation valve assembly taken along lines  7 — 7  of FIG. 2; 
     FIG. 8 is a perspective view of an alternate embodiment of the inhalation/exhalation valve assembly having an integrally formed tab in the housing for connecting to straps for holding the mask in position; 
     FIG. 9A is a perspective view of the exhalation/inhalation valve body; 
     FIG. 9B is a front elevation view of the exhalation/inhalation valve body; 
     FIG. 10 is a sectional side view of the valve assembly taken along lines  10 — 10  of FIG. 9B; 
     FIG. 11 is an exploded perspective view of the valve assembly; and, 
     FIG. 12 is also an exploded perspective view of the valve assembly. 
    
    
     DETAILED DESCRIPTION 
     Referring initially to FIGS. 1 and 2, a half facepiece respiratory mask  10  includes an inhalation/exhalation valve assembly  13  and a half facepiece mask assembly  16 . The inhalation/exhalation valve assembly  13  of the present invention is one form of a service module. The term “service module” is defined as a module having at least two or more conduits and designed so as to provide communication between at least two of the conduits. In the example shown, the service module is an inhalation/exhalation valve assembly. Other service applications requiring two conduits and integrally formed so as to provide communication therebetween are also part of the invention. Another example is a communications device in electrical communication with the inhalation or exhalation valve. In the embodiment shown, the valve assembly  13  is removably attached to the mask assembly  16  as described below and the valve assembly  13  is capable of being sealed with a single gasket  14  (FIG.  3 ). The mask  10  provides for a modular arrangement such that the inhalation/exhalation valve assembly  13  can be used with different sized mask assemblies  16 . The inhalation/exhalation valve assembly  13  is preferably contained in a single housing  80 . The mask assembly  16  is a half facepiece with a relatively rigid plastic hardshell member  22  having an elastomeric material  25  bonded thereto. The valve assembly  13  is described herein in connection with a mask assembly  16  suitable for high “G” force applications, however, as it will be apparent to those of ordinary skill in the art, the valve assembly  13  could also be integrated into modular designs for other types of masks including but not limited to full facepiece masks, standard half facepiece masks, half facepiece masks with detachable goggles, or the like. 
     The mask  10  has an inlet  103  for connection to a breathing gas tube and an outlet  108  (FIG. 10) leading to an exhalation port  111  for exhalation. The mask  10  can be provided with additional openings  34 ,  37  for microphones, drink tubes, anti-suffocation valves, or the like as shown in FIG.  3 . Also, the mask  10  can be equipped with a single opening to receive the inhalation and exhalation conduits or a single opening for a pair of conduits arranged so as to have concentric passageways for inhalation and exhalation gases as known to those of ordinary skill in the art. 
     Turning to FIG. 3, the half facepiece mask assembly  16  has an opening  28  for the inhalation valve, an opening  31  for the exhalation valve, and a pair of auxiliary openings  34  and  37 , which can be used for drink tubes, anti-suffocation valves and the like as mentioned above. The openings are all disposed on a substantially planar portion  40  that is integrally formed in the hardshell member  22 . The planar portion  40  is described in greater detail hereafter. 
     The hardshell member  22  is preferably an injection molded ABS. Suitable plastic materials include polycarbonate, polysulfone, and other thermoset plastics or thermoplastics and the like capable of being molded into a relatively rigid plastic structure, and may include fillers and additives for additional properties such as color and the like as known to those of ordinary skill in the art. The hardshell member  22  is preferably relatively rigid compared to the elastomer material  25 . The elastomeric material  25  covers most of the hardshell member  22  on the inside of the mask assembly  16  (as shown in FIG. 6) and is used wherever the mask contacts the skin of the wearer. 
     The elastomeric material  25  preferably comprises medium density silicone having a durometer of 50-70 shore A. However, other elastomers and the like would also be suitable such as any liquid injection molded or compression molded elastomer having suitable bonding and elastomeric material properties. 
     In order to make the half facepiece mask assembly  16  shown in FIG. 3, the hardshell member  22  is placed in a mold and the elastomeric material  25  is molded to the hardshell member  22  through primarily chemical bonding during the molding process with some additional support from mechanical bonding around the hardshell member  22 . 
     The mask assembly  16  is designed such that a sealed chamber  18  (FIG. 6) capable of receiving pressurized breathing gas is formed inside a portion of the mask assembly  16 . Because of the environment that the mask assembly  16  is subjected to, it is desirable to minimize the volume of this chamber  18 . For example, the pressure differential in high altitude applications and the forces associated with High G force applications make it desirable to minimize the volume of the breathing gas chamber  18 . A larger breathing gas chamber where pressure is higher than ambient would create greater forces urging the mask away from the face of the user thus requiring tighter restraints to keep the mask on the face. Also, when the pilot experiences high G forces, the pressure of the breathing gas may be automatically increased, and this additional pressure increases the above-described forces that urge the mask away from the wearer&#39;s face. 
     As shown in FIG. 6, the chamber  18  is sealed by a primary faceseal  43  that defines an area that is substantially less than the size of the entire inside area of the mask assembly  16 . When the mask  10  is placed on a wearer&#39;s face, the primary faceseal  43  extends over the bridge of the nose, around the sides of the nose and mouth and across the mental protuberance to subdivide the inside of the mask assembly  16  into a relatively small chamber that is sealed to confine the breathing gas. 
     Returning to FIGS. 1-3, the hardshell member  22  of the mask assembly  16  has a shape that extends outward from the face to form a canopy  46  to define the volume inside the mask assembly  16  for receiving pressurized gases. The hardshell member  22  extends outward to form the canopy  46  and terminates in the planar portion  40  (FIG.  3 ). As described above, the planar portion  40  can be equipped with one or more openings for various purposes. The planar portion  40  and the openings provide a modular design such that a valve assembly  13  can be used with different size mask assemblies  16  or vice versa. 
     For example, in order to provide a proper seal for different face sizes and face shapes, it is often desirable to provide more than one size mask. The present invention provides for interchanging different mask assemblies  16  with a single inhalation/exhalation valve assembly  13 . 
     Also, the arrangement of the openings and the design of the inhalation/exhalation valve assembly  13  as described in detail herein provide for easy attachment and sealing between the mask assembly  16  and the valve assembly  13 . 
     The hardshell member  22  of the mask defines the boundaries of the canopy  46  and also extends beyond the canopy  46  and conforms to the shape of the wearer&#39;s face. The hardshell member  22  extends beyond the canopy  46  below and to the sides of the canopy  46 . The extension of the hardshell member  22  is most prominent along the “wings”  47  or the portion conforming to the shape of the cheek of the wearer. “Wings” are defined herein as extended portions of the hardshell member  22  that extend beyond the canopy across the cheeks of the wearer and conform substantially to the curvature of the wearer&#39;s face. 
     The hardshell member  22  of the present invention has a first portion  49  that defines the canopy  46  and has a second portion  52  that extends around the canopy  46 . The second portion  52  extends underneath the canopy  46  and around the sides of the canopy  46  to conform to the shape of the wearer&#39;s face. The second portion  52  terminates along a peripheral edge  153 . The elastomeric material  25  continues past the edge  153 . The hardshell member  22  also includes a cut out portion  55  that provides for access to the nose by the wearer. In the cut out portion  55 , the hardshell member  22  is removed but the elastomeric material  25  remains. The hardshell member  22  surrounding the cutout portion  55  provides some additional support to the sealing area around the bridge of the nose. 
     In FIGS. 4 and 5, the hard shell portion  22  is shown with the inhalation opening  28  and exhalation openings  31  provided. As shown, the first portion  49  of the hardshell member  22  has a planar portion  40  that extends across the front of the canopy  46 . The first portion extends from the planar portion  40  inward toward the wearer&#39;s face and terminates at the second portion  52 . The transitions between the planar portion  40  and the side walls  58  of the first portion  49  are radiused to provide an aerodynamic design. At the junction  53  (best shown in FIGS. 1 and 4) between the first portion  49  and the second portion  52 , the curvature of the hardshell member  22  changes relatively abruptly from a curve dictated by the first portion  49  defining a canopy  46  to the curvature of the second portion  52  which is dictated by the curvature of the wearer&#39;s face. The second portion  52  extends around the canopy  46  on the wearer&#39;s cheeks and extends to points  61  and  64  located on opposite sides of the wearer&#39;s chin. 
     The extension of the hardshell member  22  beyond the canopy  46  and along the curvature of the cheeks of the wearer provides several advantages including distribution of the forces associated with the retention system for the mask. Under high G force conditions and high altitude flying where the restraint system may pull the mask very tightly against the face, the distribution of the forces over a larger area provides for much greater comfort. If a mask has a small area of contact, the force is concentrated in that area and leads to discomfort. 
     In FIG. 5, the cut-out region  55  is shown. Part of the hardshell member  22  surrounding the cut-out region  55  includes a relatively thin strip of material  67  that, because it is made of the hardshell material is more rigid than the elastomeric material portion  25 , and provides support to maintain the seal across the bridge of the nose. Because the material has some degree of flexibility and because of the curvature of the member  67  (best shown in FIG. 4) it functions similar to a spring that is pre-loaded such that it urges the elastomeric material  25  toward the face to keep the seal around the bridge of the nose. 
     In FIG. 6, the inside of mask assembly  16  is shown. As described previously, when the mask  10  is placed on the face of the wearer, a faceseal  43  extends around the bridge of the nose, down each side of the nose and mouth and across the mental protuberance. The faceseal  43  preferably comprises a reflective seal that bends to conform to the shape of the wearer&#39;s face. The space extending from the faceseal  43  to the front of the mask assembly  16  where the openings are located defines the intended breathing gas chamber. 
     A peripheral elastomeric section  70  (FIG. 1) of the elastomeric material  25  extends past the edge of the hardshell. Rolled edges  73  are shown along the cheeks and downward under the chin. The peripheral section  70  is not intended to define a pressurized gas chamber. The primary purpose of peripheral section  70  is to bear and to comfortably distribute the load on the wearer&#39;s face from the mask restraint/harness system. The peripheral section  70  also helps to maintain the proper alignment of the mask  10  on the wearer&#39;s face under high G force conditions. Peripheral section  70  may be provided with a rolled over edge  73  that provides additional padding so that the mask fits comfortably over the face. If the faceseal  43  is breached, the peripheral section  70  may also function to restrict the breathing gas from escaping from the inside of the mask  10 . The peripheral section  70  may include a rollover edge  73  that is connected on the cheeks near the nose portion and that extends around the remainder of the perimeter of the mask assembly  16 . The hardshell member  22  extends almost to the perimeter of the mask assembly  16  as described above. The elastomeric material  25  covers the inside of the hardshell member  22  along the portions of the hardshell that conform to the shape of the wearer&#39;s face to cushion the face and extends for a short distance beyond the edge of the hardshell member  22  at the perimeter of the mask for increased comfort. Accordingly, the mask transitions from an elastomeric covered hardshell portion conforming to the curvature of the wearer&#39;s face to a section of entirely elastomeric material extending around the perimeter of the mask. The hardshell member  22  and not the elastomeric material  25  is intended to provide the primary support to the mask assembly  16  along the cheek contours of the wearer&#39;s face. As an alternative, the elastomeric material  25  could be coextensive with the hardshell member  22  and therefore not extend beyond the hardshell periphery. 
     The peripheral section  70  and the mask assembly  16  conform to the shape of the wearer&#39;s chin such that the mask assembly  16  is substantially supported from the chin during use. The mask assembly  16  is designed such that the primary support and positioning of the mask is provided by the hardshell member  22  extending across the cheek portions and by the peripheral section  70  and the inside of the mask assembly  16  cradling the wearer&#39;s chin. As a result the restraint forces required for high altitude and high G force conditions are spread across a large area of the face and are concentrated across the width of the face and on the chin and lower jaw. In contrast, the portion of the mask that crosses the bridge of the nose is very well cushioned and is designed to seal with maximum comfort. 
     The elastomeric material  25  is bonded against the hardshell member  22  and extends approximately one-quarter to one-half of an inch beyond the edge of the hardshell member  22  around the perimeter of the mask. The extended portion of the elastomeric material  25  around the peripheral edge of the hardshell may terminate in the rollover edge  73 . The elastomeric material  25  covers the hardshell member  22  on the inside of the mask and may provide a rollover edge  73  along the boundary defined by the peripheral section  70 . However, the elastomeric material  25  primarily covers the hardshell member  22  which extends along the curvature of the wearer&#39;s face in the cheek regions to cushion it against the wearer&#39;s face. The peripheral section  70  also restrains the free flow of gas if the primary seal is breached. 
     Turning to FIG. 7, one form of the service module is an inhalation/exhalation valve assembly that is combined into a single housing  80  that fits onto the canopy  46  of the mask assembly  16  and is attached to the mask assembly  16  such that the valve assembly  13  can be sealed to the mask assembly  16  with a single gasket  14  (FIG. 3) disposed on the planar portion  40 . The valve assembly  13  has a breathing gas inlet  103  with a channel  109  to a demand type one-way inhalation valve  92 . A portion of the incoming breathing gas is split off and provides a pressure source for the pressure compensated exhalation valve  95 . The split-off portion of the incoming breathing gas provides a force for biasing the exhalation valve  95  in the closed position. The valve assembly  13  is described in greater detail below. 
     In FIG. 8, the housing  80  for the inhalation and exhalation valves  92 ,  95  is provided with an integrally formed tab  100  that can be connected to the straps  97  of a harness system (not shown) for extending about the head of the wearer and for supporting the mask assembly  16 . The arrangement of the tab  100  to connect to the harness system provides the advantage that it further reduces the complexity of the mask assembly  16  because it does not require any strap mounts to be manufactured on the mask assembly  16 . Accordingly, the tab  100  eliminates some parts from the mask assembly  16  which makes it easier to manufacture as part of a modular system. As an alternative, the tab  100  could be attached to the hardshell member  22  or the elastomeric material  25 . It is known in the art to provide various harness systems for attaching masks to the head of the wearer. The mask of the present invention is readily adaptable for use with these harness systems. The harnesses may be connected directly to the housing  80  or to the mask  10 , as described above, or may be connected to structures connected to the housing  80  or mask  10  as known to those of ordinary skill in the art. 
     Turning to FIGS. 9A-9B, the inhalation/exhalation valve housing  80  is designed to be constructed of a single plastic body with one or more openings for breathing related and other passageways to the interior of the mask assembly  16 . By arranging the inhalation and exhalation valves  92 ,  95  (FIG. 10) in a single plastic housing capable of attaching to the mask assembly  16  on a planar portion  40 , the sealing of the mask assembly  16  and the valve assembly  13  is simplified. The housing  80  has an inlet  103  for the breathing gas mixture and an outlet  108  (FIG. 10) leading to an exhalation port  111  for exhalation. 
     One way inhalation valves  92  for receiving sources of pressurized breathing gases and pressure compensated exhalation valves  95  are generally known to those of ordinary skill in the art, and therefore the valve assembly  13  will be discussed briefly. As shown in FIG. 10, a main passageway  109  receives breathing gas under pressure from a source of pressurized breathing gas (not shown). The breathing gas flows until it fills up the inlet area outside the inhalation valve  92 . A one way inhalation valve  92  provides for a demand system. When the wearer breathes in, the pressure on the opposite side of the inhalation valve  92  is reduced such that the valve opens. Breathing gas from the inlet area enters the breathing chamber until the pressure inside the chamber reaches a level sufficient to close the valve  92 . 
     A portion of the inlet breathing gas is split off and passes through a connecting tube  94  that is directed to the outside of the one-way exhalation valve  95 . The split-off pressurized breathing gas provides a force against the exhalation valve  95  that biases the valve  95  in the closed position. When the wearer of the mask exhales, the pressure generated by the wearer has to overcome the force of the diverted inlet gas in order to open the valve  95 . When the exhalation pressure reaches a sufficient level, the valve  95  opens and the exhalation gases are released through the outlet  108  to the surrounding atmosphere. 
     The exhalation gases can be released in at least two ways. If the housing  80  for the valve assembly  13  is sealed along its entire periphery by the gasket  14  (FIG.  3 ), then an exhalation port  111  (FIGS. 1 and 9A) must be provided in the housing  80 . As known to those of ordinary skill in the art, the exhalation port  111  preferably includes a one-way check valve and/or a mechanical guard to prevent debris and the like from entering the mask through port  111 . 
     As an alternative, the housing  80  may be sealed to the mask assembly  16  around the valves  92  and  95  but not completely sealed around the periphery of the housing  80 . In this manner a gap can be provided between the housing  80  and the mask assembly  16  below or around the exhalation valve  95  outside the mask assembly  16  such that the exhalation gases can escape through the gap after passing through the exhalation valve  95 . 
     The housing  80  provides the mechanical guard to prevent debris from entering the mask  10  because of the torturous path that the exhalation gas travels from the exhalation valve through the gap between the valve housing  80  and the mask assembly  16 . The pathway of the exhalation gases is shown by arrow  113  in FIG.  10 . 
     The valves  92 ,  95  are disposed inside the housing  80  such that they are both capable of being sealed with the single gasket  14  along a single plane. The gasket  14  fits on the planar portion  40  of the mask assembly  16  as shown in FIG.  3 . The inhalation valve  92  and exhalation valve  95  both extend into the canopy  46  and are attached by threaded members that fit inside the mask assembly  16  and attach to the portion of the valves that extends into the mask assembly  16  as described in detail below. 
     Turning to FIGS. 11-12, the housing  80  has a ledge  110  formed around a cylindrical hollow member  112  for the inhalation valve  92 . The ledge  110  engages with the planar portion  40  (with gasket  14  disposed therebetween) such that the valve assembly  13  is sealed to the mask assembly  16 . An inlet valve seat  115  carries a one way flapper valve  118 . The inlet valve  92  is covered by a protective guard  121 . The protective guard  121  is threaded such that it attaches to the cylindrical hollow member  112  on the inside of the mask assembly  16  such that the protective guard  121  secures the cylindrical hollow member  112  to the mask assembly  16 . 
     The exhalation valve  95  is arranged such that a ledge  130  is established substantially coplanar with the ledge  110 . The arrangement of the valves  92 ,  95  inside the housing  80  enables the valve assembly  13  to be sealed by the gasket  14  along a single plane. 
     The exhalation valve  95  includes a first coil spring  200  seated in the housing  80 . A diaphragm  203  is disposed adjacent to the first spring  200 . A spring cup  206  supports a second spring  209  that is disposed between the spring cup  206  and an exhalation plate  212 . An exhalation support member  215  holds the springs  200 ,  209 ; the spring cup  206 ; and the exhalation plate  212  in alignment. An exhalation valve seat  220  that defines ledge  130  attaches to the exhalation support member  215  to hold the exhalation plate  212  in position in alignment with the other parts. A hollow cylindrical tube  240  is disposed on the exhalation valve seat  220  and extends into the mask assembly  16  when the valve assembly  13  is mounted on the mask assembly  16 . A ring nut  245  attaches to the tube  240  on the inside of the mask assembly  16  by means of fasteners  250  to secure the valve assembly  13  to the mask assembly  16 . The fasteners  250  extend through the ring nut  245 , the exhalation valve seat  220 , the exhalation support member  215  and into the housing  80  to maintain all of the parts in axial alignment. The exhalation valve  95  is a one-way valve that opens when the pressure exerted by the wearer during exhalation is applied to the exhalation plate  212  causing the diaphragm  203  to deflect and cause an opening that allows the air to escape through outlet  108  (FIG. 10) to atmosphere. 
     It is to be understood that the inhalation/exhalation valve assembly  13  is one form of service module. Other modules suitable for use with two or more conduits at least two of which are interconnected by one or more integral connecting passages would also be suitable. The service module of the present invention provides a single externally mounted module having two conduits and designed so as to provide for communication between the conduits. 
     While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.