Patent Publication Number: US-2004040562-A1

Title: Mask and spherically configured valve

Description:
FIELD OF THE INVENTION  
       [0001] The invention generally relates to valves and, more particularly, the invention relates to valves used with filter masks.  
       BACKGROUND OF THE INVENTION  
       [0002] Air filtration masks (referred to herein as “filter masks”) are widely used to protect people from air borne contaminants. For example, air borne dust particles are a commonly known hazard at a variety of different types of work sites. Consequently, workers at such sites often wear filter masks to avoid inhaling the potentially dangerous dust particles. To these ends, various types of filter masks are manufactured from a filtering material that filters contaminants from inhaled air. One problem with such filter masks, however, is that the filter material often creates an air resistance that can inhibit free breathing. To at least partially alleviate this problem, some filter masks include a one-way valve that permits its wearer to exhale more freely.  
       [0003] When the wearer is not exhaling, the valve should remain closed. In fact, this is preferred for all physical orientations of the mask. For example, if a flap valve is not normally biased closed by some force other than gravity, then it may open when the wearer bends over or otherwise causes the force of gravity to urge the flap away from its valve seat. Consequently, the filter mask may not provide the intended air filtering benefits.  
       [0004] The art has responded to this problem by providing filter masks with one-way valves that normally are biased closed in all physical orientations. One such valve includes a flexible flap that is specially molded to remain normally biased against its valve seat in all orientations. Although useful for its intended purpose, such a valve is relatively expensive to produce because it requires a specially molded flap. Other functionally similar configurations have been developed, but still are relatively complex, unreliable, and/or expensive to produce.  
       SUMMARY OF THE INVENTION  
       [0005] In accordance with one aspect of the invention, a valve includes a flexible member and a support member having a member connector. The flexible member is coupled with the member connector, which is substantially spherically configured.  
       [0006] In some embodiments, the support member includes a valve seat and the flexible member is biased against the valve seat when in a closed mode to prevent fluid flow. The valve seat may have an effective center, and the member connector may be spaced from the effective center. Illustratively, the valve seat is in a single plane. Alternatively, the valve seat is in one or more planes, and the member connector is in a different plane than such one or more planes to normally maintain the flexible member against the valve seat.  
       [0007] The flexible member may be biased to be in a spherical configuration when in the closed mode. In some embodiments, the flexible member is manufactured to be normally flat when not connected to the member connector. The support member may include a substantially spherically configured rib having a radius substantially equal to that of the member connector. In still other embodiments, the support member also includes a valve seat that is connected to the member connector. The valve seat, member connector, and flexible member together form a void when in the closed mode.  
       [0008] In accordance with another aspect of the invention, a valve having a closed mode for preventing fluid flow and an open mode for permitting fluid flow includes a normally flat flexible member and a support member having a valve seat and member connector. The flexible member is coupled with the member connector and biased to be substantially spherically configured when in the closed mode. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009] The foregoing and advantages of the invention will be appreciated more fully from the following further description thereof with reference to the accompanying drawings wherein:  
     [0010]FIG. 1 schematically shows a filter mask manufactured in accordance with illustrative embodiments of the invention.  
     [0011]FIG. 2A schematically shows an isometric view of a valve configured in accordance with illustrative embodiments of the invention, where the valve is in a closed mode.  
     [0012]FIG. 2B schematically shows an isometric view of the valve shown in FIG. 2A where the valve is in an open mode.  
     [0013]FIG. 3 schematically shows an exploded view of the valve shown in FIG. 2A.  
     [0014]FIG. 4 schematically shows a plan view of a support member with coupled flap of the valve shown in FIG. 2A.  
     [0015]FIG. 5 schematically shows a cross-section of the support member and flap shown in FIG. 4 along line  5 - 5 .  
     [0016]FIG. 6 schematically shows a cross-section of the support member and flap shown in FIG. 4 along line  6 - 6 .  
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS  
     [0017] In illustrative embodiments of the invention, a filter mask is manufactured with a spherically configured valve, which, during normal use, should remain closed in all orientations when its user is not exhaling. To that end, the valve has internal components that normally bias a sealing flap in a spherical configuration when the valve is closed. Details of illustrative embodiments are discussed below.  
     [0018]FIG. 1 schematically shows an exemplary filter mask  10  constructed in accordance with illustrative embodiments of the invention. The mask  10  may be similar to that disclosed in co-pending provisional U.S. patent application Ser. No. 60/386,297, having the title, “FACE MASK AND METHOD OF MANUFACTURING THE SAME,” filed on Jun. 5,2002, and naming Robert A. Brunell and George A. Snow and as joint inventors. The disclosure of that patent application is incorporated herein, in its entirety, by reference. Of course, it should be noted that although the mask  10  shown in that patent application and FIG. 1 are discussed, differently configured filter masks may be used in various embodiments of the invention.  
     [0019] The filter mask  10  includes a filter layer  12  that is supported on a porous, but relatively more rigid, molded support base  14 . In illustrative embodiments, the filter layer  12  and support base  14  are sufficiently resilient so that the filter mask  10  has a normally open concave area for sealingly receiving a user&#39;s nose and mouth. The filter mask  10  also includes a nose piece (not shown) to properly position the mask  10  against the user&#39;s nose, straps  16  to secure the mask  10  to the user&#39;s face, and a peripheral rim  18  that contours to the user&#39;s face when worn. The filter mask  10  also includes the above noted one-way valve  20 , which more freely permits air to be exhaled. Details of the valve  20  are discussed below with reference to FIGS.  2 A- 6 .  
     [0020] The straps  16  may be constructed from a resilient rubber material, or other conventionally known material (e.g., a non-resilient fabric), that permits a secure and snug fit between the user&#39;s face and the rim  18 . The straps  16  thus apply an inwardly directed force for those purposes. At a minimum, this force should be sufficient at least to hold the mask  10  to the user&#39;s face. Moreover, it is preferred that the rim  18  have a contoured surface that contours to the user&#39;s face. Accordingly, when the straps  16  apply the noted inwardly directed force to the mask  10 , the contoured surface should be sufficiently flexible and resilient to shape to the user&#39;s face. This ensures that the substantial majority of the user&#39;s air is inhaled and exhaled through the filter mask  10 . In some embodiments, the rim  18  includes additional material (e.g., rubber) to provide an effective seal against the user&#39;s face.  
     [0021]FIG. 2A- 6  show details of illustrative embodiments of the valve  20 . In particular, with reference to FIGS. 2A and 2B, the valve  20  includes a rigid plastic housing containing a flexible member, referred to herein as “flap  22 .” The Those skilled in the art sometimes refer to the flap  22  as a “diaphragm.” The interior of the housing is manufactured so that when the valve  20  is in a closed mode, the flap  22  is positioned to prevent air flow through the valve  20 . Conversely, when the valve  20  is in an open mode, the flap  22  is positioned to permit air flow through the valve  20  in one direction. Consequently, movement of the flap  22  causes the valve  20  to transition between open and closed modes.  
     [0022] More specifically, as shown in the exploded view of FIG. 3, the valve  20  includes the above noted flap  22  and two housing portions  24  and  26 . Namely, the housing portions  24  and  26  include a support member  24  for connecting to the flap  22 , and a cover  26  for covering the flap  22 . The cover  26  and support member  24  may be connected in any manner known in the art, such as with a snap-fit or ultrasonic welding. In illustrative embodiments, the cover  26  includes a tooth  28  that mates with a corresponding slot  30  in the support member  24  to align the two housing portions  24  and  26 . In addition, the cover  26  may have a small protruding flange (not shown) around its periphery to snap into flexible mating ridges (not shown) on the support member  24 .  
     [0023] The cover  26  has an open portion  36  to freely permit air flow, and a covered portion  38 . The open portion  36  includes a plurality of fingers  40  that extend from the covered portion  38  to the periphery of the cover  26 . The covered portion  38  may include a logo or other indicia indicating the make or type of mask  10 . In alternative embodiments, the cover  26  does not include the covered portion  38 . Specifically, in such embodiments, the substantial majority of the cover  26  may be open to freely permit fluid flow.  
     [0024] The flap  22  illustratively is produced from a flexible material that normally is substantially flat. In illustrative embodiments, the material is conventional gum rubber. More specifically, in illustrative embodiments, conventional processes stamp the flap  22  from a sheet of gum rubber to be in a substantially circular shape. No specialized molding processes are necessary to control the degree of curvature of the flap  22 . It should be noted that although a specific material has been discussed (i.e., gum rubber), its discussion is exemplary and not intended to limit the scope of the invention.  
     [0025] Accordingly, in a manner similar to the discussed sheet of gum rubber, the flap  22  normally is substantially flat when not coupled with the valve  20 . The flap  22  also may include a pair of holes  42  for receiving an anchor  52  that couples the flap  22  with the support member  24 . In alternative embodiments, the flap  22  may have an integrally molded anchor (not shown) to secure with corresponding coupling holes  50  in the support member  24 .  
     [0026] The support member  24  is specifically manufactured to cause the flap  22  to be spherically configured when the valve  20  is in its closed mode. More particularly, the flap  22  is considered to be “spherically configured” when its surface has a radius of curvature that is substantially uniform in all directions. In other words, to be spherically configured, all points on the surface of the flap  22  have a substantially identical (but finite-i.e., not flat) radius of curvature. More generally, an element of the valve  20  is considered to be spherically configured when such element has a radius of curvature that is substantially uniform. Accordingly, to spherically configure the normally substantially flat flap  22 , the support member  24  has spherically configured components. The flap  22  is mounted within the housing so that the spherically configured elements of the support member  24  cause the flap  22  to be spherically configured. The flap  22  thus may be considered to be normally spherically configured when within the valve  20 .  
     [0027] To these ends, the support member  24  includes a spherically configured flap connector portion  44  for connecting with the flap  22 , and a pair of spherically configured ribs  46  for providing structural support to the flap connector portion  44 . The flap connector portion  44  has a relatively large radius of curvature that also causes the ultimate radius of curvature of the flap  22  to be relatively large. In addition, the support member  24  also includes a valve seat  48  that cooperates with the flap  22  to seal the valve  20 . The valve seat  48  illustratively is in a single plane that is different than that of the flap connector portion  44 . As shown below, positioning the valve seat  48  in a different plane than the flap connector portion  44  more effectively permits the flap  22  to be spherically configured. In illustrative embodiments, the ribs  46  also are spherically configured.  
     [0028] To secure the flap  22 , the flap connector portion  44  has a pair of holes  50  formed therein to receive the anchor  52  for securing the flap  22 . As noted above, the anchor  52  may be separate from the flap  22 , or may be integral with the flap  22 . When separate, the anchor  52  may be any conventional material used for such purposes, such as plastic or rubber. In addition, the anchor  52  is manufactured to provide an inwardly directed force that normally forces the flap  22  to be substantially flush against the flap connector portion  44 . Specifically, when the flap  22  is forced inwardly, its outer periphery bears against the valve seat  48 , while a portion of its surface is substantially flush against the connector portion  44 . The flap  22  also may bear against the ribs  46 . The combination of forces cooperate to cause the flap  22  to be spherically configured. As noted above, because it is spherically configured, the flap  22  should remain closed in all orientations when the mask user is not exhaling.  
     [0029] One important feature of illustrative embodiments is the fact that the flap  22  is connected to the flap connector portion  44  at a location that is off center relative to the entire valve  20 . Specifically, the flap  22  is not connected to the flap connector portion  44  at its center or at its periphery. While still enabling some relative flap stiffness, this arrangement permits the cracking pressure (i.e., the minimum air pressure to open the valve  20 ) to be lower than if the same flap  22  were connected at the substantial center of the valve  20 . In addition, in a manner different than if it were connected at its periphery, this arrangement also permits the entire 360 degrees of the flap  22  to lift from the valve seat  48  to permit air flow. It should be noted that principles of the noted off-center connection applies to other valves that are not necessarily circular. For example, for a valve that is not symmetrically shaped with an exact center, a connection spaced away from an effective center should provide similar results.  
     [0030] To illustrate the spherical configuration of various embodiments, FIGS. 5 and 6 respectively show cross sections of the valve  20  along lines  5 - 5  and  6 - 6  of FIG. 4. Although FIG. 4 shows the flap  22  and support member  24  only, FIGS. 5 and 6 are drawn to show the cross sections as if the cover  26  were attached to the support member  24 . As shown, from both sides of the valve  20 , the flap  22  is spherically configured and thus, remains flush against the valve  20  seat  48 . A sufficient air flow in the direction indicated in FIG. 5 causes the flap  22  to lift from the valve seat  48 , thus opening the valve  20 . Air flow in the opposite direction thus is inhibited because the flap  22  cooperates with the valve seat  48  to prevent it from passing through the valve  20 .  
     [0031] In some embodiments, the flap connector portion  44  does not smoothly merge into the valve seat  48 . In such embodiment, the valve seat  48  forms an abrupt wall at the outer radial portion of the flap connector portion  44 . The flap  22 , valve seat  48  and flap connector portion  44  thus together form a small void at that point.  
     [0032] Although various exemplary embodiments of the invention have been disclosed, it should be apparent to those skilled in the art that various changes and modifications can be made that will achieve some of the advantages of the invention without departing from the true scope of the invention. These and other obvious modifications are intended to be covered by the appended claims.