Abstract:
In one embodiment, a snorkel includes a conduit having a first end and a second end, a mouthpiece joined to the conduit second end, an arm adjacent the conduit first end and connected to a seal, wherein the seal is configured to pivot with respect to the conduit from a first position where the seal does not obstruct an opening in the first end of the conduit, to a second position, where the seal covers the opening in the first end of the conduit, and a float configured to control movement of the arm, wherein the float and conduit are configured so that movement of the float is guided along the length of the conduit and submerging the float causes the float to move along the conduit toward the first end of the conduit, which pivots the arm from the first position to the second position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The instant invention is a continuation application of U.S. patent application Ser. No. 13/603,230, filed Sep. 4, 2012 that is a continuation of U.S. patent application Ser. No. 11/484,060 filed Jul. 10, 2006, which was a continuation of U.S. patent application Ser. No. 11/075,490, now U.S. Pat. No. 7,077,127, filed Mar. 3, 2005, which was a continuation application of U.S. patent application Ser. No. 10/717,391, now U.S. Pat. No. 6,904,910, filed Nov. 17, 2003 and claims the benefit of U.S. Provisional Patent Application Ser. No. 60/428,034 entitled “Flip Top Valve For Dry Snorkels,” filed Nov. 20, 2002. The instant invention also makes reference to Disclosure Document No. 534,494 titled “Flip Top Valve for Dry Snorkels” filed Jul. 10, 2003. The disclosures of U.S. Pat. Nos. 7,077,127 and 6,904,910, U.S. patent application Ser. Nos. 13/603,230 and 11/484,060, U.S. Provisional Patent Application Ser. No. 60/428,034, and Disclosure Document 534,494 are hereby incorporated by reference in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is generally related to snorkels used by skin divers and swimmers. More particularly, this invention is concerned with preventing water from entering and flooding a snorkel. 
         [0004]    2. Description of the Prior Art 
         [0005]    Skin divers and swimmers use the snorkel as a means to breathe while swimming face down on the water surface. The snorkel functions as a conduit between the diver&#39;s mouth and the overhead air. Typically, the open end of the snorkel conduit extends a short distance above the water surface. Occasionally, due to swimming movements or wave action, small amounts of water flow or splash into the open end of the snorkel and partially floods the conduit. An experienced skin diver can sense when water enters the snorkel and responds by immediately stopping inhalation. Respiration is resumed after the snorkel has been purged of water. Inexperienced skin divers find occasional flooding especially troublesome because, undetected, water can be inhaled resulting in coughing and extreme discomfort. 
         [0006]    Water will also flood the snorkel when the swimmer deliberately dives below the water surface. The snorkel conduit will be completely flooded with water when the swimmer returns to the surface. When the open end of the snorkel is again above the water surface, the flooded conduit is purged for respiration by exhaling an explosive blast of air into the mouthpiece. 
         [0007]    Surface tension forms the purging blast of air into a bubble that spans the cross section of the snorkel conduit. Pressure within the bubble expands the bubble toward the open end of the conduit. As the leading surface of the bubble moves away from the mouthpiece, the bulk of the water within the conduit is pushed ahead of the bubble and out the open end. 
         [0008]    The purging bubble of air will slip past water that adheres to the inside surface of the conduit. After the purging air bubble is spent, residual water will flow down the inside surface toward the mouthpiece. Also, water which splashes into the open end of the snorkel conduit due to swimming movements or wave action will typically strike and adhere to the inside surface of the conduit and thereafter flow toward the mouthpiece. Water accumulates at the lowermost portion of the snorkel conduit, typically adjacent the mouthpiece, and can soon obstruct the conduit. Unless the conduit is completely blocked, a slow and cautious inhalation is possible after which another purging exhalation can be made. 
         [0009]    The respiratory effort needed to purge a snorkel is significant. Many skin divers and swimmers lack the respiratory strength needed to completely puree a flooded snorkel with a single exhalation, and must repeat the purging procedure several times. Also, water will sometimes enter the snorkel just as the swimmer has completed an exhalation, leaving very little air in the lungs to satisfactorily complete a purge. 
         [0010]    As a consequence of the difficulties typically encountered by a skin diver or swimmer when trying to purge a flooded snorkel, a number of inventions have been proposed to protect the snorkel opening with devices that prevent water from entering the conduit, even when the swimmer dives underwater. 
       SUMMARY OF THE INVENTION 
       [0011]    The instant invention is a valve for the top end of skin diving snorkels having a conduit with an open end above the water surface, and an underwater end that terminates in a mouthpiece. The mouthpiece provides a flow path between the conduit and the interior of the diver&#39;s mouth. The conduit&#39;s above water opening is in-line with the conduit&#39;s longitudinal axis, thereby providing a substantially straight and unrestricted respiratory flow path. The top valve consists of a flexible diaphragm mounted on a compound linkage. The linkage is attached to the conduit adjacent the top opening. A buoyant component activates the valve linkage whenever the snorkel starts to descend below the water surface. By the time the open end of snorkel is underwater, the linkage has moved the diaphragm over and against the top opening thereby preventing water from entering the conduit. Conversely, when the top of the snorkel is above the water surface, the diaphragm is moved to the side of the conduit, completely away from the top opening and out of the respiratory flow path. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    A detailed description of the invention is made with reference to the accompanying drawings wherein like numerals designate corresponding parts in the several Figures. 
           [0013]      FIG. 1  is a side view of a snorkel having a top valve that has been constructed in accordance with the principles of the instant invention. 
           [0014]      FIG. 2  is a close-up side view of the open valve of  FIG. 1 . 
           [0015]      FIG. 3  is a close-up oblique view of the open valve of  FIG. 1 . 
           [0016]      FIG. 4  is a longitudinal sectional side view of the snorkel of  FIG. 1  shown with the valve closed. 
           [0017]      FIG. 5  is a close-up side view of the closed valve of  FIG. 4 . 
           [0018]      FIG. 6  is an upward-looking oblique view of the closed valve of  FIG. 4 . 
           [0019]      FIG. 7  is another close-up side view similar to  FIG. 2 . 
           [0020]      FIG. 8  is an oblique view showing an alternate configuration. 
           [0021]      FIG. 9  is a close-up side view of another alternate configuration showing the valve open. 
           [0022]      FIG. 10  is a close-up side view of the alternate configuration of  FIG. 9  showing the valve closed. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Referring to  FIG. 1 , a snorkel  10  in accordance with an embodiment of the invention is pictured in the approximate position of use by a diver swimming face down on water surface  12 . (For clarity, the diver is not shown in the FIGS.) The words “upper” and “lower” or “above the water surface” and “below the water surface,” or the like, are made with reference to the orientation of snorkel  10  go shown in  FIG. 1 . 
         [0024]    Snorkel  10  includes conduit  20  having upper end  20   a  that extend into the air above water surface  12 . The lower end of conduit  20  is closed by purge valve  40 . Purge valve  40  is arranged to allow fluid, for example water or saliva, to flow freely from conduit  20  to ambient. Although the preferred configuration includes purge valve  40 , the instant invention can be incorporated on snorkels that do not include purge valve  40  by terminating the underwater end of conduit  20  at mouthpiece  42 . 
         [0025]    Purge valve  40  is, typically, a flexible diaphragm of a resilient material, for example silicon elastomer or the like, which is restrained in such a way that it can selectively flex under slight pressure to allow flow in one direction only. Reverse pressure forces the diaphragm to seal closed. Consequently, purge valve  40  will prevent the reverse flow of water from ambient into conduit  20 . 
         [0026]    Mouthpiece  42 , above purge valve  40 , branches from the side of conduit  20 . Mouthpiece  42  is adapted to be held by the mouth of the diver and provides a flow path from conduit  20  to the interior of the mouth 
         [0027]    Conduit  20  is constructed of a rigid or semi-rigid material, for example, acrylic or vinyl plastic or the like. Conduit  20  is configured to approximately follow the curvature of the diver&#39;s head. The upper portion of conduit  20  smoothly curves to place upper end  20   a  approximately over the center of the head. 
         [0028]    Providing a substantially smooth flow path that is free of abrupt changes in path direction facilitates respiration and purging. While not so limited, the curvature of conduit  20  may, for example, follow an elliptical path around the diver&#39;s head. Alternately, the upper portion of conduit  20  can be straight. 
         [0029]    As best seen in  FIG. 3 , the upper portion of conduit  20  terminates at opening  24 . Opening  24  is directly in-line with the conduit&#39;s longitudinal axis, thereby providing a substantially straight and unrestricted respiratory flow path to ambient. 
         [0030]    Referring to  FIGS. 2 and 7 , valve assembly  50  is mounted on conduit  20  adjacent opening  24 . Valve assembly  50  consists of a compound linkage that moves diaphragm  44  from an open position (shown by  FIG. 2 ) to a closed position (shown by  FIG. 5 ), and vice-versa. When diaphragm  44  is at the open position, it is located to the side of conduit  20 , completely out of the respiratory flow path. When diaphragm  44  is at the closed position, it is located to provide a watertight covering of opening  24 . 
         [0031]    Diaphragm  44  is loosely mounted on arm  52  by tab  46 . The movement of arm  52  is guided by the compound action of short link  60  and long link  70 . One end of short link  60  is joined to arm  52  by pivot  62 . The other end of short link  60  is joined to one side of snorkel opening  24  by pivot  64 . Similarly, one end of long link  70  is joined to arm  52  by pivot  72 ; and the other end of long link  70  is joined to the opposite side of snorkel opening  24  by pivot  74 . 
         [0032]    The lengths of links  60  and  70 ; and the relative positions of pivots  62 ,  64 ,  72  and  74  are chosen to form a quadrilateral linkage assembly that moves diaphragm  44  from the open to the closed positions, and vice-versa. Referring to  FIG. 7 , link  60  is distance R60 long. Link  70  is distance R70 long. Pivots  62  and  72  are distance R62 apart. Pivots  64  and  74  are distance R74 apart. R60, R70, R62 and R74 form a four-sided polygon. 
         [0033]    The dimensions of R60, R70, R62 and R74; and the locations of pivots  62  and  72  on arm  52 ; and the locations of pivots  64  and  74  on conduit  20 ; are carefully chosen so that assembly  50  will either hold diaphragm  44  to the side of conduit  20  out of the respiratory flow path as shown by  FIG. 2  (the “open” position), or place diaphragm  44  over and against opening  24  as shown by  FIG. 5  (the “closed” position). Furthermore, the dimensions and locations are chosen so that valve assembly  50  is stable only when at either the fully open or completely closed positions. 
         [0034]    Referring to  FIG. 7 , links  60  and  70 , diaphragm  44 , and arm  52 , are shown in the open position as solid lines; and in the closed position as dashed lines identified  60 C,  70 C,  44 C ad  52 C respectively. The movement of link  70  between the open and closed positions is depicted by the double arrowed arc identified “Open-Closed”. 
         [0035]    While not so limited, empirical studies have determined that R74 should be equivalent to the outside diameter of conduit  20 . The ratio of R60, R70, and R62 to R74 should be approximately 0.3 to 1.4 to 0.3 to 1. In addition, links  60  and  70  should be nearly parallel when valve assembly  50  is at the open position (see  FIG. 7 ). 
         [0036]    Valve assembly  50  moves in response to the movement of float  30 . The movement of float  30  is transmitted to valve assembly  50  by rod  32 . One end of rod  32  is firmly joined to float  30 . The other end of rod  32  is pivotally joined with pivot  72  of link  70  (best seen in  FIG. 6 ). 
         [0037]    When float  30  is not in the water, the weight of float  30  pulls rod  32  downward thereby pulling arm  52  to the open position. When float  30  is in the water, the resultant buoyant force pushes rod  32  upward thereby pushing arm  52  to the closed position. The upward pointing arrow in  FIG. 4  depicts the direction of closing movement of float  30  and rod  32 . 
         [0038]    Diaphragm  44  is, typically, a flexible diaphragm of a resilient material, for example silicon elastomer or the like. Diaphragm  44  is loosely mounted on arm  52  by tab  46 . The loose mounting enables diaphragm  44  to flex and tilt as needed to make a watertight seal against the periphery of opening  24 . 
         [0039]    Float  30  is typically a low-density material, for example closed-cellular ridged foam or the like. Alternately, float  30  can be hollow. As best seen in  FIG. 6 , float  30  loosely surrounds and is thereby guided by conduit  20 . Although a spherical external surface is pictured, float  30  can be cylindrical, elliptical, or any other useful shape. By appropriately adjusting the length of rod  32 , float  30  can be located anywhere along conduit  20  between valve  50  and mouthpiece  42 . When float  30  is located relatively close to valve  50 , the closing response of valve  50  is delayed until almost all of conduit  20  is underwater. When float  30  is located relatively close to mouthpiece  42 , the closing response of valve  50  will be very sensitive to water movement up conduit  20 . The ideal location of float  30  is a compromise so that valve  50  is fully closed by the time conduit  20  is completely underwater, but not so sensitive as to be inadvertently closing due to wave action or swimming movement. 
         [0040]    Arm  52  is typically fabricated by molding a rigid material, for example polycarbonate plastic. Links  60  and  70  are typically fabricated by bending wire, for example, 316 stainless steel wire. Links  60  and  70  can also be fabricated by stamping and bending thin sheet metal stock, for example, 316 stainless steel sheet. Alternately, links  60  and  70  can be fabricated by molding a rigid material, for example polycarbonate plastic. 
         [0041]    Referring to  FIGS. 1 and 2 , when float  30  is entirely out of the water, the weight of the float has pulled rod  32 , and consequently pivot  72 , downward. Conversely, referring to  FIGS. 4 and 5 , when water travels up snorkel  10  and starts to submerge float  30 , for example, due to wave action or a deliberate diving action by the swimmer, buoyant force will overwhelm the weight of float  30  and the weight of valve assembly  50 , causing pivot  72  to move upward, which causes arm  52  to drop diaphragm  44  over opening  24 . Short link  60  serves to provide the sideways and dropping movement of arm  52  and, thereby, diaphragm  44 . Advantageously, the volume of float  30  is chosen so that sufficient buoyant force is available to close valve  50 . However, an overly large float  30  will be bulky and unwieldy. Consequently, the size of float  30  is a compromise that provides adequate buoyancy but not excess bulk. 
         [0042]    When float  30  is partially or completely submerged, buoyant force will cause diaphragm  44  to cover opening  24 , thereby preventing water from entering conduit  20 . If opening  24  is closed while the swimmer is inhaling, inhalation flow will be blocked to prevent the undesirable entry of water into conduit  20 . If opening  24  is closed while the swimmer is exhaling, the pressure of exhalation will flex diaphragm  44  outward thereby allowing the exhaled gases to continue to escape. Any subsequent inhalation will be blocked until float  30  is once again above the water. 
         [0043]    If the swimmer removes mouthpiece  42  from the mouth while in the water, for example to talk, snorkel  10  will often be at least partially flooded when the swimmer returns mouthpiece  42  to the mouth for additional use. Similarly, if the swimmer enters the water without mouthpiece  42  already in the mouth, snorkel  10  will often be at least partially flooded when the swimmer first puts mouthpiece  42  in the mouth. In addition, saliva from the mouth can drain into conduit  20  and accumulate below mouthpiece  42 . 
         [0044]    Water and saliva in conduit  20  are purged by forcefully exhaling air into mouthpiece  42 . Surface tension forms the exhaled air into a bubble that expands upward in conduit  20 . As the leading surface of the bubble moves away from mouthpiece  42 , the bulk of the water within conduit  20  is pushed ahead of the bubble and out opening  24 . This purging action is facilitated by the instant invention because opening  24  is substantially in line with the longitudinal axis of conduit  20 . 
         [0045]    In the event that float  30  moves upward (due, for example, to wave action) during the purging exhalation, diaphragm  44  will close, but the expulsion of water will continue because the internal pressure will flex the diaphragm outward, away from opening  24 , and allow the water inside conduit  20  to escape. Consequently, inventive snorkel  10  does not prevent a purging exhalation even when conduit upper end  20   a  is nearly or completely underwater. 
         [0046]    When optional purge valve  40  is provided, a forceful exhalation will also expand downward, forcing fluid below mouthpiece  42  to flow to ambient through purge valve  40 . The outflow of water will flex purge valve  40  outward. Consequently, a purging exhalation forces water within conduit  20  to be cleared both above and below mouthpiece  42 . 
         [0047]    The volume of the portion of conduit  20  between mouthpiece  42  and purge valve  40  is advantageously sized to hold, away from the respiratory flow path, saliva or any residual water that remains after a purging exhalation. Empirical studies have determined that a volume equivalent to ten percent (10%) of the snorkel&#39;s total internal volume can be sufficient for this purpose. 
         [0048]    When a swimmer dives below the water surface and snorkel  10  is completely submerged, float  30  will have moved upward, thereby causing diaphragm  44  to cover opening  24 . As the diver continues to swim below the water surface and looks around, the orientation of snorkel  10  will not necessarily remain upright. Head movements will change the orientation of snorkel  10  relative to the water surface. For example, snorkel  10  will be completely inverted relative to the water surface when the swimmer is looking directly upward. 
         [0049]    When a swimmer first dives underwater, buoyancy can provide sufficient force to close valve assembly  50  when snorkel  10  is fully submerged, ambient pressure can also act to hold diaphragm  44  firmly against opening  24 . Underwater, the pressure inside snorkel  10  can never be greater than ambient because excess pressure will be vented through the check valve action of diaphragm  44  or, when snorkel  10  is inverted, purge valve  40 . The ambient pressure at the depth of diaphragm  44 , or purge valve  40  when snorkel  10  is inverted, will determine the maximum pressure inside conduit  20 . As the swimmer dives deeper, ambient pressure against the lungs will compress the lungs thereby maintaining the respiratory tract at or near ambient pressure. Although instinctively the swimmer will stop breathing when underwater, and may plug mouthpiece  42  with the tongue, the pressure of the respiratory tract will involuntarily bleed through mouthpiece  42  into conduit  20 . However, unless the swimmer continuously exhales into snorkel  10  as the depth increases, the pressure inside snorkel  10  will be somewhat less than ambient. The slightly lower pressure inside conduit  20  with respect to ambient pressure is used by the instant invention to keep diaphragm  44  firmly sealed against opening  24 , no matter what the orientation of snorkel  10 . 
         [0050]    Furthermore, when snorkel  10  is inverted, the buoyant force will be working to move float  30  away from the closed position, but the gravitational force and the differential pressure force across diaphragm  44  will be working to hold diaphragm  44  in the closed position. For diaphragm  44  to remain at the closed position even when snorkel  10  is inverted, the net pressure force against the diaphragm plus gravitational force must be greater than the buoyant force from float  30 . The preferred configuration includes purge valve  40  because purge valve  40  provides the benefit of maintaining the pressure inside conduit  20  less than ambient when snorkel  10  is inverted underwater, thereby maximizing the pressure force holding diaphragm  44  closed. 
         [0051]    It is advantageous to cover valve assembly  50  in order to prevent external objects or material, for example seaweed, from snagging on or otherwise interfere with the function of linkages  60  and  70 , arm  52 , and diaphragm  44 . Any such cover must be open at the top so that it will not interfere with respiratory or purging flow. Referring to  FIG. 8 , cover  20   b  is shown as an example of a means to protect the valve components and also streamline the top of conduit  20 . Cover  20   b  is shown protruding from the side of conduit  20 , but other configurations can be conceived that are appropriate, for example a ring that completely surrounds valve  50  and conduit end  20   a , and possibly float  30 . 
         [0052]      FIGS. 9 and 10  show an alternate configuration, open and closed respectively, of the instant invention in which float  30  is directly attached to and is carried by link  70 . To accommodate the placement of float  30  on link  70 , pivot  74  must be located as shown in  FIGS. 9 and 10 . As with the configuration of  FIG. 1 , the dimensions of the four-sided polygon formed by the various links must be chosen so that diaphragm  44  moves completely out of the respiratory flow path when float  30  is above the water surface. 
         [0053]    Other variations on the diameter, cross-section shape and radius of curvature of conduit  20 ; size and shape of float  30 ; size, shape and location of valve assembly  50  on conduit  20 ; size and shape of cover  20   b ; and various methods to adjust the mouthpiece location and orientation relative to the conduit, are contemplated. 
         [0054]    It is understood that those skilled in the art may conceive of modification and/or changes to the invention described above. Any such modifications or changes that fall within the purview of the description are intended to be included therein as well. This description is intended to be illustrative and is not intended to be limiting. The scope of the invention is limited only by the scope of the claims appended hereto.