Abstract:
A second stage diving regulator of the type used by scuba divers is provided. The regulator comprises a regulator housing and a mouthpiece. The regulator housing includes an inhalation chamber having a port, and a demand valve that releases air to the port in response to inhalation through the port. The mouthpiece comprises a unitary housing attachable to the regulator housing and includes a one-way exhalation pathway, thus obviating the need for an exhalation pathway in the regulator housing itself. Inhalation no-return valves can be additionally incorporated into the fluid pathway from the regulator housing to the diver to prevent fluids from flowing into the regulator housing through the mouthpiece. Saliva and exhaled air with its attendant moistures and pathogenic entities can thus be prevented from entering the regulator housing. The mouthpiece can be made easily detachable and can be sanitized between uses, making it particularly well suited for rental and instructional purposes. The disclosed invention keeps the interior spaces of the regulator clean and dry even when the regulator is not in place in the diver&#39;s mouth, thus extending regulator life and preventing a dangerous and irritating free-flow condition from occurring due to icing when used in cold water. The mouthpiece can be variously constructed to differentiate common-use mouthpieces from those owned individually.

Description:
This is a division of application Ser. No. 09/182,619, filed Oct. 29, 1998, now U.S. Pat. No. 6,089,225. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of scuba diving and, more particularly, to mouthpieces used with diving regulators. 
     BACKGROUND OF THE INVENTION 
     Regulators are devices that allow scuba divers to breathe air, or the like, while under water. The regulator uses valves to release air from high pressure tanks, typically through the action of an inhalation responsive diaphragm. Most often, a first stage regulator is attached to the tank. A second stage regulator is then connected to the first by a flexible hose and is supported by a mouthpiece retained in the mouth of the diver. This configuration requires minimal breathing effort since it locates the inhalation responsive elements closer to the center of pressure of the diver&#39;s lungs. 
     The regulator further includes a no-return exhaust valve mounted within the housing or incorporated into the inhalation diaphragm. Since exhalation occurs back through the regulator, the inhalation chamber is filled with expired air before the next inhalation cycle. U.S. Pat. No. 2,747,572, to Gagnan, locates the demand valve close to the respiratory port while placing the exhaust valve at a much greater distance, thus minimizing, though not entirely eliminating, the re-inhalation of expired air. 
     Due to its open nature, the second stage regulator can flood with corrosive salt water and abrasive sand and silt. U.S. Pat. No. 4,079,735, to Gaffney, shows a plug that fits into the mouthpiece to prevent the regulator from flooding when not in use, thus extending its serviceable life. However, the regulator may still flood when the plug is removed before use. 
     Most regulators release air directly into the respiratory port. A resultant venturi lowers the inhalation chamber pressure and reduces inhalation effort. However the venturi can become self-sustaining and spontaneous free-flow of air may occur if the regulator is not in place in the diver&#39;s mouth. U.S. Pat. No. 4,010,746, to Pedersen, teaches a vane extending into the respiratory port to draw water into the regulator. The inflow of water equalizes pressure across the diaphragm, thus closing the demand valve and disrupting the free-flow. Unfortunately, this approach requires that the regulator flood with harmful and corrosive sea water. 
     Compressed air cools as it exits the demand valve and moisture in the diver&#39;s exhalation condenses and can freeze on the demand valve if the regulator is used in cold water. This can cause the demand valve to remain open and result in an irritating and potentially dangerous uncontrolled free-flow. U.S. Pat. No. 4,356,820, to Trinkwalder, discloses a metallic vane to capture heat from the diver&#39;s exhalation and conduct it to the demand valve, thus preventing regulator free-flow due to icing. 
     Regulators are frequently shared by many divers, especially in rental operations and diver training programs. Pathogenic entities from one diver can be transmitted to the next. Some bacteria, such as tuberculosis, have become resistant to antibiotics. Hepatitis is difficult to kill and can survive on dry surfaces for great periods of time. And lethal new viruses, such as HIV, Marburg, and Ebola are emerging with an alarming frequency. Regulators are rinsed with fresh water after use, but this has little pathogen inactivating value. There is growing concern over this problem and some instructional agencies have even discontinued so-called buddy breathing exercises to minimize the risks associated with sharing regulators between students. 
     U.S. Pat. No. 5,570,702, to Forman, shows a disposable cover to place over the mouthpiece before each use and U.S. Pat. No. 5,755,222, to Pansard, discloses a fastener to facilitate mouthpiece replacement. Both teach against the common use of mouthpieces, thus averting the transmission of communicable diseases. However, both fail to recognize that pathogenic entities are carried past the mouthpiece and into the regulator with exhaled air and saliva. Once there, they can be transmitted to the next user. 
     None of these inventions, or others of the like, taken separately or collectively, resolve all problems resulting from the open nature of the modern regulator. Some do not even resolve the issues they were intended to. And so, even after fifty years, there still remains a need to improve the operation of diving regulators. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a mouthpiece for use with diving regulators that prevents saliva and exhaled air with their pathogenic entities from entering the regulator housing. 
     It is another object of the present invention to provide a mouthpiece for use with diving regulators that can be removed for cleaning and sanitizing. 
     It is still another object of the present invention to provide a mouthpiece for use with diving regulators that prevents water, sand, and silt from flooding the regulator. 
     It is still another object of the present invention to provide a mouthpiece for use with diving regulators that prevents free-flow due to icing when used in cold water. 
     It is yet another object of the present invention to provide a mouthpiece for use with diving regulators that prevents free-flow when the mouthpiece is not in place in the diver&#39;s mouth. 
     It is still another object of the present invention to provide a mouthpiece for use with diving regulators that minimizes the re-inhalation of expired air. 
     The present invention accomplishes its intended objectives by providing a detachable mouthpiece to sealingly interfit the respiratory port of a regulator. The mouthpiece includes its own exhalation pathway. One or more no-return valves can be provided to prevent saliva, exhaled air, pathogenic entities, water, sand, and silt from entering the regulator. 
     Since both individuals and common-use agencies may use a mouthpiece of the present invention, it is possible that confusion might occur over which mouthpiece is in use. Therefore, it is still another object of the present invention to provide a mouthpiece that allows the user to differentiate common-use mouthpieces from those owned individually. 
     Further characteristics and advantages of the mouthpiece of the present invention will become apparent from a description of the preferred embodiments given hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view, shown in partial section, of a first preferred embodiment of a mouthpiece of the present invention fitted to a second stage regulator. 
     FIG. 2 is a sectional view of the housing of the mouthpiece shown in FIG.  1 . 
     FIG. 3 is an exploded view of an inhalation valve assembly suitable for use in the present invention. 
     FIG. 4 is an exploded view of an exhaust valve assembly suitable for use in the present invention. 
     FIG. 5 is an isometric view, shown in partial section, of a second preferred embodiment of a mouthpiece employing the principles of the present invention. 
     FIG. 6 is an elevational view, shown in partial section, of a third preferred embodiment of a mouthpiece of the present invention fitted to a second stage regulator. 
     FIG. 7 is an exploded view of an inhalation—exhaust valve assembly and anti free-flow device suitable for use in the mouthpiece of FIG.  6 . 
     FIG. 8 is a sectional view of the housing of the mouthpiece shown in FIG.  6 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a first preferred embodiment of a mouthpiece of the present invention fitted to a second stage regulator  10 . It should be understood that regulator  10  is an illustrative regulator and is just one of many breathing devices of the type used by divers that would accrue benefit from the use of a mouthpiece of the present invention. It should be further understood that as used herein, the term “air” refers to any breathable gas. 
     Regulator  10  comprises housing  110 , demand valve  120 , diaphragm  130 , perforated cover  140 , no-return exhaust valve  150  and purge button  180 . Exhaust valve  150  is shown here as a mushroom type check valve. It allows flow in only one direction. Air stored in high pressure tanks is supplied to demand valve  120  through hose  122  from a first stage regulator (not shown). Inhalation induced differential pressure across diaphragm  130  ultimately deflects lever  126  and releases air from demand valve  120 . Air can also be manually released by depressing purge button  180 . Once released, air flows into inhalation chamber  160  and out respiratory port  112  to the diver (not shown). When regulator  10  is fitted with a conventional mouthpiece, exhalation occurs back through respiratory port  112  and inhalation chamber  160  and out exhaust valve  150 . Regulator  10  can flood with water, sand, and silt when not in place in the diver&#39;s mouth. When fitted with a mouthpiece of the present invention, water, sand, silt, saliva, and expired air and their pathogenic entities are prevented or impeded from entering regulator  10 . 
     First Preferred Embodiment 
     Mouthpiece  20 , shown in FIG. 1, comprises housing  200 , inhalation valve assembly  30 , two exhaust valve assemblies  40 , only one of which is shown, and optional locking device  24 . Housing  200 , better shown in FIG. 2, has an opening  230  formed by sleeve  210 , mouthgrip opening  250  formed by mouthgrip  260  and vent openings  240  formed by sidearms  220 . Sleeve  210  further includes groove  215  to receive an optional locking device  24  and recess  232  to receive respiratory port flange  114  and inhalation valve assembly  30 . Sidearms  220  include recesses  242  to receive exhaust valve assemblies  40 . When gripped in the mouth of the diver, mouthpiece  20  supports regulator  10  and thus maintains diaphragm  130  in a substantially fixed position relative to the diver&#39;s lungs. The regulator-mouthpiece combination has two separate exhaust routes; one through exhaust valve  150  and the other through mouthpiece openings  240 . 
     One inhalation valve assembly  30  well suited for use with mouthpiece  20  is shown in FIG.  3 . Stem  334  of mushroom type valve  330  fits into slot  314  of valve body  310 . Valve  330  is locked in place by protrusion  336  on stem  334 . Flapper  332  forms a seal with valve body surface  315 . Differential pressure in one direction will open flapper  332  and allow fluid to pass through openings  316 . Differential pressure in the opposite direction forces flapper  332  more tightly against surface  315 , thus preventing fluid flow. Barrel  313  of body  310  fits into respiratory port  112  of regulator  10 . It includes groove  312  to receive O-ring  370 . O-ring  370  engages with and seals against flange  114  of respiratory port  112 . Surface  311  of valve body  310  can optionally form a seal with recess  232  of housing  200 . 
     Exhaust valve assembly  40  is best shown in FIG.  4 . Stem  434  of valve  430  fits through opening  414  of body  410  and is held in place by protrusion  436 . Flapper  432  seals against webbed structure  418 , allowing only one-way flow through openings  416 . Surface  412  provides sealed engagement with housing  200  when installed within sidearm recess  242 . 
     During inhalation, the diver&#39;s suction is transmitted through inhalation valve assembly  30  and causes air to be released from demand valve  120  into inhalation chamber  160 . Air then flows to the diver along an inhalation fluid pathway comprising respiratory port  112 , inhalation valve assembly  30 , and mouthgrip opening  250 . The one-way nature of exhaust valve assembly  40  prevents water from entering mouthpiece  20  during the inhalation cycle. During exhalation, inhalation valve assembly  30  closes and exhaled air vents along the fluid pathways comprising mouthgrip opening  250 , sidearms  220 , exhaust valve assemblies  40 , and vent openings  240  into the surrounding water. 
     Saliva and expired air with its attendant moistures and their pathogenic entities are thus prevented from entering respiratory port  112  and inhalation chamber  160  of regulator  10 . Free-flow due to icing is prevented. Inhalation valve assembly  30  is located on a plane with the diver&#39;s lips and, thus, no previously expired air is re-breathed. And when mouthpiece  10  is not in place in the diver&#39;s mouth, water, sand, and silt are prevented from entering regulator  10 , thus extending regulator life. 
     In a rare case, regulator  10  may flood with water, chiefly through a seal failure of inhalation diaphragm  130  or exhaust valve  150 . If not in use at the time, the diver can clear regulator  10  by depressing purge button  180  while orienting regulator  10  so that water will be expelled through valve  330 . If in use, the diver can expel water through exhaust port  150  by exhaling into mouthpiece  20  while depressing purge button  180 . Having two separate exhaust pathways is particularly advantageous. Pathogenic entities washed off the interior surfaces of the regulator, or carried into the regulator by water, will be expelled through exhaust port  150  and away from the diver. 
     Rental and instructional agencies can equip their regulators with mouthpieces of the present invention to extend the life of their regulators and minimize the risk of transmitting disease. The mouthpiece can be easily removed after use and sanitized or sterilized by methods that would otherwise prove detrimental to the regulator as a whole. Nevertheless, individuals may still prefer to use their own mouthpieces. It would be of benefit to common-use agencies and individual divers if they could differentiate one mouthpiece from another. Raised lettering  270 , such as the last three letters of the word “COMMON” as shown on housing  200  of FIG. 1 can be used to differentiate a mouthpiece intended for common use from one privately owned. Other forms of indicium can also be used. For instance, a individually owned mouthpiece can be inscribed with an icon depicting a single diver, while a common-use mouthpiece can be inscribed with an icon or a group of icons representing multiple divers. A color coding scheme can also be used wherein common-use mouthpieces, or portions thereof, are of one color, and those owned individually are of another. Texture, finish and opacity can also act as indicium to differentiate one type of mouthpiece from another. Similar indicium can be used with any embodiment of the present invention. 
     Second Preferred Embodiment 
     While FIG. 1 shows a mouthpiece best suited for original equipment manufacture, FIG. 5 shows a mouthpiece well suited to retro-fit existing regulators. Mouthpiece  50  comprises housing  500  having sleeve  510  to form first opening  530  to receive respiratory port  112 . Sleeve  510  includes recess  532  to receive flange  114 , and recess  538  to receive inhalation valve body  534 . Valve  330  is installed into valve body  534  to form an inhalation valve assembly. Housing  500  further includes mouthgrip  560  with mouthgrip opening  550  to provide fluid communication with the diver. Sidearms  520  provide vent openings  540  and have recesses  542  within to receive exhaust valve assemblies  40 . Thus an inhalation fluid pathway is formed comprising respiratory port  112 , inhalation valve body  534 , valve  330  and mouthgrip opening  550 . Exhalation occurs along two exhalation fluid pathways comprising mouthgrip opening  250 , sidearms  220 , exhaust assemblies  40  and vent openings  240  into the surrounding water. 
     Third Preferred Embodiment 
     FIG. 6 shows another preferred embodiment of a mouthpiece well suited to retro-fit existing regulators. Mouthpiece  60  comprises housing  800  and valve plate assembly  70 . Anti free-flow plug  750  is removed when regulator  10  is in use. Housing  800 , best shown in FIG. 8, comprises sleeve  810  forming an opening  830  to receive respiratory port  112  and further includes mouthgrip  860  with mouthgrip opening  850  to provide fluid communication with the diver. Sidearm  820  provides vent opening  840  to provide a fluid pathway to the surrounding water. Valve plate assembly  70 , best shown in FIG. 7, comprises plate  710 , valve  330  and valve  430  to allow inhalation flow through openings  717  and exhalation flow through openings  715 . When installed in housing  800 , valve plate assembly  70  is supported by protrusion  844  on one end and flange  713  on the other. It is further supported by surface  842 . Seals are formed by the interference of barrel  712  and plate surface  718  with housing  800  and sleeve  810  with respiratory port  112 . Flanged recess  815  of housing  800  is provided for the optional use of locking device  24 , such as a cable tie or Velcro strip. As with mouthpieces  20  and  50 , mouthpiece  60  provides fluid pathways from regulator  10  to the diver and from the diver to the surrounding water and prevents saliva and exhaled air and their pathogenic entities from entering respiratory port  112  and inhalation chamber  160  of regulator  10 . 
     Valve plate assembly  70  is installed into housing  800  by inserting it through any of openings  830 ,  840  or  850 , urging it into place and snapping it into position. Mouthpiece  60  is easily disassembled for cleaning by distending housing  800  and extracting valve plate assembly  70 . Mounting the inhalation and exhaust valves on a common carrier is particularly advantageous since fewer parts are involved and there is no ambiguity over valve orientation. 
     Distal end  730  of valve plate  710  has been shown as a short member. But, as a matter of choice, distal end  730  could be angled away from mouthpiece  60  and elongated to direct escaping bubbles away from the diver&#39;s vision. This bubble deflector can be an integral part of valve plate  710 . Alternatively, a separate bubble deflector can be attached to barrel end  730  or to mouthpiece housing  800 . Similar bubble deflectors can be used with any embodiment of the present invention. 
     Plug  750  prevents free-flow from occurring when regulator  10  is not in use by the diver. Plug  750  is inserted through opening  850  of housing  800  and is held in place by the interference of handle  754  with sidewalls  848 . Plate  752  having slot  756  can be placed either in contact with or in close proximity to valve  330 . In either case, valve  330  is prevented from opening freely, thus allowing pressure to increase within inhalation chamber  160  and preventing free-flow from occurring. If plate  752  is in hard contact with valve  330 , excess pressure in inhalation chamber  160  will vent through exhaust valve  150 . If plate  752  is only in close proximity to valve  330 , excess pressure will vent through either exhaust valve  150  or inhalation valve  330 , depending on the relative cracking pressures of each. Plug  750  can be clipped to the diver&#39;s harness to hold regulator  10  in place when not in use. Alternatively, plug  750  can be attached to mouthpiece  60  at slot  824  by lanyard  770 . Plug  750 , or the like, can be used with any embodiment of the present invention. 
     Manufacturing Considerations 
     Housings  200 ,  500  and  800  and valves  330  and  430  can be molded in flexible elastomers, such as silicone or neoprene rubber by known methods. Valve bodies  310 ,  410  and  534  and valve plate  710  can be economically molded in plastic or fabricated in metal. Any or all parts can be fabricated to include indicium to differentiate common-use mouthpieces from those owned individually. 
     The invention is not limited to the use of mushroom type no-return valves. There are many other types of valves known in the art that can be used with equal success. For instance, duck-bill, spring loaded plate, ball and cup, and swing plate types of no-return valves can be easily adapted for use with a mouthpiece of the present invention. Moreover, the number and placement of valves along the fluid pathways is not limited to that shown in the preferred embodiments. Multiple valves could be used in series or parallel and placed inside or outside the envelope of the mouthpiece housing. 
     The mouthpiece housing need not actually include a mouthgrip as such. The mouthgrip can be replaced by a mouthgrip mounting tube so that users can customize the mouthpiece assembly to their own liking. For instance, an anatomical mouthpiece, such as that shown in U.S. Pat. No. 5,203,324 to Kinkade, could be attached to the mouthpiece housing without losing the advantages of the present invention. 
     Housings  200 ,  500  and  800  have been illustrated as singular molded entities, but, again, no such limitation is intended. Housings could just as well be fabricated as multi-part assemblies and can include special adapters or the like to more readily facilitate attachment and sealing to respiratory ports of different design or dimension than that illustrated herein. Conversely, a mouthpiece housing with integral inhalation and exhaust valves could be molded as a single unit. 
     Respiratory port  112  of regulator  10  has been shown as an outwardly extending tube. Again, no such limitation is intended. The respiratory port of regulator  10  could also be manufactured as an inwardly extending tube or as a simple opening. A mouthpiece employing the principles of the present invention could be adapted to sealingly interfit respiratory ports of any design without departing from the novel scope and nature of the invention. 
     The diver or a manufacturer could eliminate or render inoperative exhaust valve  150  if a mouthpiece of the present invention is to be used with the breathing device. While this eliminates one possible leak path into the regulator, it sacrifices the advantage of having independent exhaust pathways. Nevertheless, if such a modification were made to the regulator, the inhalation valve could also be eliminated from the mouthpiece design, although several more of the advantages of the mouthpiece would be lost. Since there would be no exhalation pathway through the regulator housing, exhaled air with its attendant moisture and pathogenic entities would be impeded from entering the inhalation chamber of the regulator. However, flooding would occur if the regulator were not in place in the diver&#39;s mouth. 
     While the present invention has been shown in what is thought to be its most practical embodiments, it will be apparent to those skilled in the art that numerous modifications can be made without departing from the novel scope of the invention. Hence, the proper scope of the present invention should be determined only by the broadest interpretation of the appended claims so as to encompass all such modifications and equivalents.