Abstract:
A face piece/reservoir combination that is molded as one piece. By integrating the face piece and reservoir bag into one single piece, the mask conserves space and reduces the number of parts while maintaining adequate reservoir volume. The mask has an edge on the face cup that provides a larger sealing area for the users face and provides a more comfortable fit than existing masks. The mask may be configured as a simple constant flow mask or it may include valves, allowing it to function as a phase dilution mask. The mask may be equipped with a rebreather bag and valves to function as a rebreather/phase dilution mask

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims benefit of U.S. provisional patent application Ser. No. 60/785,038 filed Mar. 23, 2006, which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to a passenger oxygen dispensing unit of the type used on aircraft with pressurized cabins by passengers during decompression emergencies to provide supplemental oxygen.  
       BACKGROUND OF THE INVENTION  
       [0003]     Modern pressurized passenger aircraft fly at altitudes in the range of 18,000 to 40,000 feet. At these altitudes the air is at a reduced density because the atmospheric pressure is much lower than at sea level. Thus, the partial pressure of oxygen in the air is not sufficient to sustain normal respiration. Consequently, there has been a need for a system to supply additional oxygen for the survival of passengers in the event of a depressurization emergency of the airplane cabin.  
         [0004]     In the prior art, especially in U.S. Pat. Nos. 4,098,271 and 4,832,017, there are shown emergency oxygen breathing apparatuses that include a facepiece having valves. The facepiece is designed to cover the nose and mouth of the user and is connected to an oxygen delivery tube. A bag which functions as a reservoir is connected between the facepiece and the delivery tube and the reservoir permits an efficient use of the limited oxygen supply. The masks are normally presented automatically on depressurization. For some masks, in order to activate the flow of oxygen, the facepiece and bag assembly are typically pulled down by the passenger.  
         [0005]     What is needed is a supplemental passenger oxygen mask that conserves space, reduces the number of parts while maintaining adequate reservoir volume, and provides a more comfortable fit.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention meets the above-described need by providing a face piece/reservoir combination that is molded as one piece. By integrating the face piece and reservoir bag into one single piece, the mask conserves space and reduces the number of parts while maintaining adequate reservoir volume. The mask has an edge on the face cup that provides a larger sealing area for the users face and provides a more comfortable fit than existing masks. The mask may be configured as a simple constant flow mask or it may include valves, allowing it to function as a phase dilution mask. The mask may be equipped with a rebreather bag and valves to function as a rebreather/phase dilution mask. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which:  
         [0008]      FIG. 1  is a perspective view of the supplemental passenger oxygen mask of the present invention;  
         [0009]      FIG. 2  is a side elevation view of the mask shown in  FIG. 1 ;  
         [0010]      FIG. 3  is a cross-sectional view taken along lines  3 - 3  of  FIG. 2 ;  
         [0011]      FIG. 4  is a side elevation view of the body prior to forming the mask;  
         [0012]      FIG. 5  is a cross-sectional view taken along lines  5 - 5  of  FIG. 4 ;  
         [0013]      FIG. 6  is a side elevational view of an alternate embodiment of the present invention; and,  
         [0014]      FIG. 7  is a cross-sectional view taken along lines  7 - 7  of  FIG. 6 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Referring generally to  FIGS. 1-5  and initially to  FIG. 1 , a supplemental passenger oxygen mask  10  is formed by a unitary member that includes both a reservoir  40  and a cup-shaped mask portion  16 . The reservoir  40  has a flow indicator  41  and an inlet  42  for attachment of a tube  49  that leads to an oxygen source. The oxygen source may comprise an oxygen cylinder, chemical oxygen generator, or the like. Actuation of the flow of oxygen may be accomplished in numerous ways as will be evident to those of ordinary skill in the art. The cup-shaped mask portion  16  has an edge  28  formed due to the fold that engages with the face of the user to form a seal during use. The sides of the cup-shaped mask portion  16  may be provided with an exhalation valve  31  and an ambient inhalation valve  37 . Also, the valve housings  38  may be provided with an attachment member  50  for connecting a head harness  51  to the mask  10 .  
         [0016]     As shown in  FIG. 2 , the mask  10  may be provided with a relatively flat end  20  where the flow indicator and gas inlet are located. While in use, the reservoir  40  has a wall  25  that curves outward and then inward from the end  20  toward the mask portion  16 . The wall  25  extends into the mask portion  16  where it is angled outward and terminates in an edge  28  formed by the fold. The edge  28  engages with the face of the user to form a seal. The head harness strap  51  connects to the attachment member  50 . The head harness strap  51  may be formed out of a resilient flexible material. In use, the mask portion  16  is placed over the mouth and nose of the user and the head harness strap  51  is stretched around the head of the user to hold the mask  10  in position against the face of the user.  
         [0017]     Turning to  FIG. 3 , an inverted end of the body  13  forms the cup-shaped mask portion  16 . The cup-shaped portion  16  includes an end wall  22 . The end wall  22  supports an inhalation check valve  34 . The side wall  19  of cup-shaped portion  16  is disposed adjacent to the wall  25  of the body  13  to form a double walled area. Side wall  19  is attached to side wall  25  by means of valve housings  38  in the example shown. At the end of the cup-shaped portion  16 , a folded over transition from the wall  19  to the wall  25  forms the edge  28  that contacts the face of the user. The edge forming the lip  28  and the choice of materials results in a more comfortable fit compared to prior art masks having separate reservoir bags and cup-shaped breathing masks constructed of relatively rigid plastic materials.  
         [0018]     The mask  10  may be provided with three separate valves as shown in the figures. The valves include an exhalation valve  31 , the inhalation check valve  34 , and an ambient inhalation valve  37 . The valve housings  38  contain valve flappers and springs (not shown). A mechanical flow indicator  41  may be attached to the base of the reservoir bag  40  which indicates when oxygen is flowing to the mask  10 . Alternatively, an inflatable flow indicator option is also available. As will be evident to those of ordinary skill in the art, provisions for a lanyard for actuating flow when the mask  10  is pulled toward the face of the user can also be made with this design.  
         [0019]     Referring to  FIGS. 4-5 , the mask  10  of the present invention may be formed from a unitary body of flexible material. For example, the mask  10  may be molded from a clear silicone material such as Baysilone LSR 2050, which is a liquid, injection moldable silicone available from GE Silicones, Waterford, New York. Other materials are also suitable as will be evident to those of ordinary skill in the art based on this disclosure. The mask body  13  may be initially formed in the shape of a hollow oblate spheroid. Oblate is defined herein as flattened or depressed at the poles  11 ,  12 . Spheroid is defined herein as a figure resembling a sphere where sphere is defined as a body whose major circumferences approximate to circles. The body  13  may be provided with a thicker section  14  and a thinner section  15  to improve flexibility. Alternatively, the body  13  may be constructed of uniform thickness throughout. Other hollow elongate shapes are also suitable as will be evident to those of ordinary skill in the art based on this disclosure. After the body  13  is initially formed, the cup portion  16  may be formed by pushing one end  17  (i.e., the short radius end) of the body  13  inward to form walls  19  and  22  ( FIG. 3 ) and attaching the inward folded wall  19  of the inverted portion to the wall  25  of the body  13 . The mask body  13  is molded as one piece with openings  26 ,  27  for receiving valves  31  and  37 , and head harness attachments  50 . Openings  26 ,  27  are capable of aligning when the body  13  is inverted to form the cup-shaped portion  16 . Valve housings  38  are installed in the aligned openings. The valve housings  38  extend through the walls  19  and  25  and secure the walls  19 ,  25  together to fix the cup-shaped portion  16  and a reservoir  40  formed by the remaining portion of the body  13 .  
         [0020]     Turning to  FIG. 6 , a rebreather/phase dilution type mask  100  has a body  103  similar to the mask  10  shown in  FIGS. 1-3 . The body  103  may be constructed of a material having uniform thickness or the body  103  may include a thinner wall section  104  and a thicker wall section  105 . In order to recycle a portion of exhaled air, the mask  100  includes a rebreather bag and an additional valve as described in detail below. The mask  100  also includes a cup-like mask portion  106  and a reservoir section  109 . The reservoir section  109  has an inlet  112  with a flow indicator  115  and a tube  118  leading to an oxygen source.  
         [0021]     The mask portion  106  terminates at an edge  128 . An ambient exhalation valve  129  is disposed in a valve housing  131 . The valve housing  131  includes an attachment member  134  for connecting the mask  100  to a head harness  137 . The mask  100  includes a reservoir inhalation valve  140 .  
         [0022]     Turning to  FIG. 7 , the rebreather passenger mask assembly functions as a hybrid version of current reservoir bag passenger masks. Metered oxygen flows through the tube  118  into reservoir section  109 . Oxygen flow is indicated by the flow indicator  115  located at the base of the reservoir section  109 . During inhalation, oxygen is drawn from the reservoir section  109  through the reservoir inhalation valve  140 . When the oxygen in the reservoir section  109  is depleted, a spring loaded flapper in a rebreather inhalation valve  149  opens which allows exhaled air from a separate rebreather bag  143  to be inhaled. When the rebreather bag  143  is also depleted, the ambient inhalation valve  146  opens to allow ambient air (i.e., cabin air) to enter the mask portion  106 . Both the ambient inhalation valve  146  and the reservoir inhalation valve  140  employ specially sized springs to prevent the valves from opening out of sequence. When the user exhales, the inhalation valves  140 ,  149  and ambient air valve  146  close and the rebreather exhalation valve  149  opens allowing the initial slug of exhaled air to empty into the rebreather bag  143 . When the rebreather bag  143  is full, the ambient exhalation valve  152  opens to allow the rest of the exhalation to empty into the ambient air. This valve  152  also employs a specially sized spring to allow the valve to open at the proper point in the breathing cycle. The object of the rebreather bag  143  is to capture the first portion of the exhalation which is rich in oxygen content and relatively low in carbon dioxide. This first portion of the exhalation corresponds to the gas that remains in the airways of the upper respiratory tract and in areas external to the user that do not reach the gas exchange zones of the lungs.  
         [0023]     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.