Abstract:
Embodiments of improved snorkeling equipment are disclosed, each enabling a swimmer to submerge his or her head and body a few feet beneath the water surface, to swim freely beneath the water surface without concern for the position of the air tube, and to draw in and expend out air with ease.

Description:
This is a continuation-in-part application of Ser. No. 08/893,663, filed on Jul. 11, 1997, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates to the field of snorkeling equipment. More specifically, this invention relates to snorkeling equipment that has been modified for use by a person who is unable to scuba dive because of certain physical limitations, but who nonetheless desires the recreational experience of swimming completely submerged in the water, as is the case in scuba diving. 
     2. Description of Prior Art 
     Certain people are physically unable to scuba dive because their ears cannot take the pressure of the greater depths, or because they have difficulty breathing the compressed gases used in breathing tanks. Moreover, scuba diving presents other obstacles to enjoyment. For example, scuba diving equipment can be expensive to own or rent, and the safe operation of such equipment requires training. 
     The recreational experience of completely submerged swimming, however, could be had if there were snorkeling equipment that permitted submerged swimming at depths of five feet or less, a range of depth where water pressure would be physically tolerable and air could be comfortably drawn into the lungs in lieu of compressed gases. The improved snorkeling equipment of this invention satisfies this recreational need. 
     Snorkeling equipment that is commonly available for recreational use generally consists of the following components: (1) a face mask with an adjustable rubber strap, (2) a rigid, J-shaped air tube, the short, curved end of which is fitted with a rubber mouthpiece, and (3) a rubber tether that secures the air tube to the rubber strap of the face mask so that the air tube freely depends therefrom when not in use. Although styles and materials may vary, snorkeling equipment must have these components, the basic features of which are constrained by the equipment&#39;s function as breathing apparatus designed to enable the swimmer&#39;s face to be completely submerged during swimming. To facilitate swimming, rubber or plastic swim fins may be provided as part of basic snorkeling equipment. 
     Because of the snorkeling equipment&#39;s basic functional design, the swimmer must swim along the water surface so that the long, straight end of the air tube clears the water surface and allows the swimmer to draw air into his or her mouth. Only the swimmer&#39;s face and the ventral side of his or her body remain submerged. Although the air tube could be lengthened to allow the swimmer&#39;s head and body to be completely submerged, this modification is not practical because the air tube when in use must remain more or less perpendicular with the water surface, and consequently, the range of movement of the swimmer&#39;s head and body would be severely limited by the allowable angle of the air tube relative to the water surface. 
     The improved snorkeling equipment of this invention has the following objectives: (1) to enable the swimmer to submerge his or her head and body a few feet beneath the water surface, (2) to enable the swimmer to swim freely beneath the water surface without concern for the position of the air tube, (3) to enable the swimmer to draw in and expend out air with ease, and ( 4 ) to provide the swimmer with snorkeling equipment of relatively simple construction and inexpensive parts for recreational use. These and other objectives will be apparent from the description below of the invention&#39;s preferred embodiments. 
     Others have made modifications to snorkeling equipment that are similar to some of the components of this invention in an effort to achieve the foregoing objectives. None of the prior art, however, describes, teaches, or suggests the novel combination taught by this invention. Nor does any of the prior art satisfactorily address all of the foregoing objectives. 
     U.S. Pat. No. 5,622,165 to Huang describes a snorkel diving device with a special floating disc that keeps the air tube above water level. Similarly, U.S. Pat. No. 5,351,681 to Hudson describes another design for a floating disc. Other designs that incorporate some sort of floating structure for maintaining the air tube above water are seen in U.S. Pat. No. 3,370,586 to Aragona, et al., and in Japanese Application No. 2-169393 to Tanaka. 
     Each of the foregoing designs lacks a lightweight, compact device that can provide a continuous flow of air to the swimmer so that the swimmer does not have to rely only on his or her diaphragm muscles to draw air from the atmosphere through the air pipe and down several feet of hose. It would be desirable for the swimmer to be able to draw in air with ease, notwithstanding the fact that he or she is completely submerged in water and has to draw air through a long hose connected to the air tube. When underwater, a swimmer&#39;s diaphragm must work against the pressure of water. Moreover, the length and diameter of the hose can present difficulties for breathing. The longer or narrower the hose is, the more work the diaphragm has to perform to draw in a sufficient volume of air. 
     Others have attempted to provide a suitable means for providing a continuous flow of air to the swimmer so that the swimmer does not have to rely only on his or her diaphragm muscles to draw air from the atmosphere through the air pipe and down several feet of hose. None of these solutions are satisfactory, however. 
     U.S. Pat. No. 5,535,734 to Lu, et al. discloses an optional fan blade assembly. (See FIG.  6  and Col. 4, lines 26-36.) This fan blade assembly is wind-driven. Looking at the drawing figure depicting the assembly, it is difficult to see that this assembly would provide a significant flow of air to the swimmer. For one thing, the small fan blade assembly, being disposed inside the narrow breathing tube, would not have a sufficient volume of air to propel. Moreover, the large fan blade assembly protruding through the top of the breathing apparatus is entirely dependent on wind action, which is unpredictable. Indeed, the more wind there is to drive the large fan blade assembly, the rougher the water will be, and the less stable and more prone to capsizing the floating structure will be. 
     Lu et al. teaches away from the use of gasoline-powered air pumps and other mechanically driven devices because of the known risks of mechanical failure from use of the device in water and contamination of breathing air from engine exhaust. (See Col. 1, lines 38-52.) These disadvantages are inherent in the invention of U.S. Pat. No. 4,832,013 to Hartdorn, which discloses the use of a gasoline-powered air compressor. As seen in the disclosure, this design must be able to eliminate excess engine heat, noxious exhaust gases, and water accumulation. (See Col. 2, lines 27-59.) As a result, the design is overly complicated and cumbersome. 
     U.S. Pat. No. 5,471,976 to Smith discloses a battery operated air pump. Smith employs the air pump, however, in conjunction with a “contractible tube concept” which accumulates an air supply between breath. (See Col. 2, lines 20-28.) As indicated in the disclosure, without the contractible tube concept, Smith&#39;s portable electric air pump and battery system could not deliver the necessary flow of air. Smith also employs a low pressure regulator to regulate the flow rate and pressure for safe breathing. (See Col. 2, lines 38-40.) Like Hartdorn, Smith improves upon the conventional air pump used in the diving art. An air pump, whether gasoline-powered or battery-powered, however, does not meet the objectives of this invention. 
     BRIEF SUMMARY OF THE INVENTION 
     The improved snorkeling equipment of this invention has a rigid air tube that is fitted to a float so that the air tube is kept afloat in a stable position more or less perpendicular to the water surface. Inside the floating structure is a centrifugal fan which draws the air in from the air tube and forces it to the swimmer&#39;s mouthpiece via several feet of flexible tubing. A purge valve system consisting of (1) a purge valve intake fitted between the flexible tubing and the mouthpiece, through which fresh air passes to the lungs and (2) a reservoir purge valve outlet fitted on the mouthpiece, through which stale air passes from the lungs directly into the water instead of flowing back up the air tube, ensures an unidirectional flow of air from the air tube to the mouthpiece. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     This invention is further described with the following drawings, in which: 
     FIG. 1 is a perspective view of the modified snorkeling equipment constructed in accordance with the teachings of the present invention; 
     FIG. 2 is an environmental view of the modified snorkeling equipment that shows its use; 
     FIG. 3 is a cross-sectional view of the float from one side, revealing the placement of the centrifugal fan and the power supply; 
     FIG. 4 is a close-up, partial cross-sectional view of the mouthpiece and a partial segment of the flexible tubing, revealing the purge valve system consisting of the purge valve intake and the reservoir purge valve outlet; 
     FIG. 5 is a view of another preferred embodiment of this invention, with the mouthpiece modified to permit two segments of flexible tubing to feed into it; 
     FIG. 6 is a view of still another preferred embodiment of this invention, with the mouthpiece modified to permit two segments of flexible tubing to feed into it, but with the purge valve intakes fitted at different positions; and 
     FIG. 7 is a close-up, partial cross-sectional view of the float from the top plan, revealing the placement of the centrifugal fan relative to the motor. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of this invention is shown in FIG.  1 . It has a mouthpiece  3  to which a segment of flexible tubing  4  is attached and sealed at one end; a float  5  which has a connecting joint  12  to which the segment of flexible tubing  4  is attached and sealed at its other end, a rigid air tube  13 , and a switch  14  for turning the fan inside the float on and off. The float  5  may be of virtually any shape, but preferably has a bow  15  to facilitate its travel on water along the direction of the arrow. The mouthpiece  3  has a rubber bitepiece  21 , a trunk  22 , a reservoir purge valve outlet  23 , and a purge valve intake  24 . The invention optionally has a face mask  2  with an adjustable strap  11 , and a rubber or woven fabric tether  16  that is fitted around the segment of flexible tubing  4  and the adjustable strap  11  of the face mask  2 . 
     This invention is shown in use in FIG.  2 . The float  5  bobs along at water surface  41  and keeps the air tube  13  in a stable position, more or less perpendicular to the water surface  41 . The flexible tubing  4  freely depends in the water  42  from the float  5  at the connecting joint  12 . Fresh air  43  is drawn into the air tube  13 , through the flexible tubing  4 , through the purge valve intake  24 , into the trunk  22  of the mouthpiece  3  and then into the lungs of the swimmer  50  via the bitepiece  21 . Stale air (shown as bubbles)  44  breathed out of the lungs of the swimmer  50  passes directly into the water  42  through the reservoir purge valve outlet  23 . 
     The arrangement of the components inside the float  5  is revealed in the cross-sectional view of FIG.  3 . There is scroll shaped housing  6  that houses a centrifugal fan  7 . The centrifugal fan preferably has backward-curved blades  8 . Air is drawn through the air tube  13  and into the scroll shaped housing  6  where it moves in a clockwise direction (shown by the arrows) out of the housing outlet  9 . The fan  7  and its housing  6  are enclosed within one compartment  31  of the float  5 . A connecting joint  32  perforating one of the walls of compartment  31  connects the housing outlet portion  9  to one end of a segment of flexible tubing  33 . This segment  33  is inside another compartment  34 . Another connecting joint  35  perforating one of the walls of compartment  34  joins the other end of the segment  33  to one end of another segment of flexible tubing  36 . This segment  36  is inside another compartment  37 . The other end of this segment of flexible tubing  36  is connected to connecting joint  12 , which in turn connects to the tubing  4 . The purpose of having multiple compartments inside the float  5  is to segregate the air supply from the fan motor (situated behind the fan  7  and therefore not seen in this FIG.) and the power supply  38 . The power supply  38 , preferably a lantern battery having a voltage compatible with the fan motor, is in a separate compartment  39 . A 6-volt lantern battery will power the fan for about two hours. All of the compartments are watertight. 
     “In an embodiment of the present invention, for example, the float  5  may comprise a toroidal mass of buoyant material having a space around the axis of the toroidal mass. The components described above are placed in this space. The space has a side, a top and a base, wherein the side of such space is enclosed by the toroidal mass. The top of the space is enclosed and sealed by a first circular cap and base of the space is enclosed and sealed by a second circular cap.” 
     The construction of the mouthpiece  3  is revealed in FIG.  4 . The mouthpiece  3  is Y-shaped, with a hollow trunk  22  that branches into a rubber bitepiece  21 , a purge valve intake  24  and a reservoir purge valve outlet  23 . The flexible tubing  4  is attached and sealed to the purge valve intake  24 . 
     FIGS. 5 and 6 illustrate two additional embodiments of this invention. In FIG. 5, the mouthpiece  3 A is cruciate in shape, such that the hollow trunk  22 A branches into a rubber bitepiece  21 A, a reservoir purge valve outlet  23 A directly opposite the bitepiece  21 A, and two purge valve intakes  24 A and  24 B. Attached and sealed to the purge valve intakes  24 A and  24 B are two segments of flexible tubing  4 A and  4 B which are joined together at their other ends and to another segment of flexible tubing  4 C by a rigid T-joint  25 . The flexible tubing  4 C is attached at its other end to the float  5  in the manner shown in FIG.  3 . 
     In FIG. 6, the mouthpiece  3 A again is cruciate in shape. In this embodiment, however, the hollow trunk  22 A branches into the bitepiece  21 A, a reservoir purge valve outlet  23 B of a different design from that of  23 A, and the two segments of flexible tubing  4 A and  4 B. The two purge valve intakes  24 A and  24 B are fitted to the segments of flexible tubing  4 A and  4 B at their opposite ends, and to thee rigid T-joint  25 . The flexible tubing  4 C is again attached to the rigid T-joint  25  as shown in FIG.  5 . 
     In FIG. 7, the centrifugal fan  7  in its scroll shaped housing  6  is shown along with the fan motor  60 . A drive shaft  61  connects the fan  7  to the motor  60 . The shaft  61  perforates a wall that separates the compartment  31  in which the fan  7  and the fan housing  6  are enclosed from the compartment  62  in which the motor  60  is enclosed. The motor  60  is preferably a 6-volt, 3-amp motor. 
     The drive shaft  61  perforates the wall separating the fan from the motor, but it has a watertight fitting  63  with a cotton greased plate or cap to prevent water from seeping into the motor compartment  62 . In this manner, the motor stays dry. Note that the scroll shaped housing  6  has an inlet portion  10  that is joined to the air tube  13 . Arrows in this FIG. again show the direction of travel of the air. 
     As seen in FIG. 3, the battery  38  is also housed in a separate compartment  39 . In the event that water does seep into the battery compartment, any leakage from the battery is contained and kept away from the air supply. 
     The supply of a motorized fan or some other means of forcibly drawing air through the air tube will enable this invention to be used optimally for swimming at depths of 3 to 5 feet. This invention is not designed for use at depths beyond 5 feet, as professional divers and snorkelers recommend that one have special training before swimming at depths beyond 5 feet. 
     The selection of a centrifugal fan is critical to the performance of this invention. A centrifugal fan operating within a scroll shaped housing permits the efficient distribution of air which is drawn through the inlet and forced out in one direction through the outlet. The backward-curved blades, which generate less static pressure than forward-curved blades at the same speed of rotation, are preferable because they operate at high efficiency and have non-overloading power characteristics. These performance characteristics inherent in backward-curved blades enable the fan to operate efficiently without the risk of overloading a small 6-volt, 3-amp motor. 
     Absent a complete immersion of the fan in water, motor overload and failure is unlikely. Any water that splashes into the scroll shaped housing from the inlet will be expelled with the air through the outlet as a result of the fan action. The passage of some amount of water through the flexible tubing to the swimmer does not present a problem because the swimmer can easily expel that water through the reservoir purge valve outlet. 
     The selection of low voltage, low amperage motor is preferred. A small motor allows the fan to be powered by a cheap, lightweight lantern battery. It also ensures that the entire assembly remains compact and portable. 
     While preferred embodiments of the invention have been shown and described, it will be apparent to those skilled in this art that various modifications may be made in these embodiments without departing from the spirit of the present invention. For that reason, the scope of the invention is set forth in the following claims.