Abstract:
A diving snorkel provided in the proximity of at least one of an upper opening and a mouthpiece with at least one partition extending from an inner wall of a snorkel conduit and also extending longitudinally of the conduit so as to compartmentalize the conduit in its circumferential direction, and thereby enable undesirable inflow of water to be obstructed as effectively as possible and enable efficient purging of water which enters into the snorkel.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to diving snorkels such as used by divers or swimmers. 
     Conventional snorkels comprise a snorkel conduit provided with an upper opening lying above the water surface during actual use of the snorkel, a mouthpiece lying under the water surface during actual use of the snorkel, and a lower opening including a non-return valve adapted to be opened downwards and lying under the water surface during actual use of the snorkel. 
     The known snorkel, for example, from Japanese Utility Model Registration Gazette No. 2536368 usually has its upper opening defined by a first tubular portion and a second tubular portion extending in parallel to each other. These first and second tubular portions are laterally communicate with each other via a passage. Between the first tubular portion and the second tubular portion, the conduit is substantially in a curved condition so that undesirable inflow of water into the mouthpiece through the upper opening can be obstructed as reliably as possible. 
     A quantity of water having flowed into the snorkel through the upper opening lying above the water surface during actual use of the snorkel must be forced out by a swimmer&#39;s expiration. Consequently, a larger quantity of water inflow will correspondingly increase a swimmer&#39;s physical fatigue. To alleviate such physical fatigue, it is required for the snorkel of well known art to obstruct the inflow of water through the upper opening as effectively as possible. While the snorkel of well known art intends to achieve this by curving the conduit, its inflow obstructing ability is not satisfactory. 
     Commonly to the conventional snorkels inclusive of the above-mentioned snorkel of prior art, a quantity of water staying immediately below the mouthpiece often generates turbulence as a swimmer attempts to purge out a quantity of water remaining within the snorkel by vigorous expiration. Such phenomenon may prevent the quantity of water from rapidly moving toward the upper opening. The expiration for purge thus utilized in vain will further increase the swimmer&#39;s physical fatigue. 
     SUMMARY OF THE INVENTION 
     In view of the problem as has been described above, it is an object of the invention to alleviate a swimmer&#39;s physical fatigue inevitably caused by the conventional snorkel and to eliminate the cause of such physical fatigue. 
     According to the present invention, there is provided a diving snorkel comprising a snorkel conduit provided with an upper opening, a lower opening a mouthpiece, and a non-return valve adapted to be opened downwards, wherein the snorkel conduit is provided in the proximity of at least one of the upper opening and the mouthpiece with at least one partition extending inwardly from an inner wall of the conduit and also extending longitudinally of the conduit so that the conduit is circumferentially comparmented by the partition. 
     According to one embodiment of present invention, the partition formed in the proximity of the mouthpiece lies in a region of the inner wall of the conduit opposed to a breathing seat of the mouthpiece. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a snorkel according to a principle of the invention; 
     FIG. 2 is a perspective view showing an upper portion of the snorkel as partially broken away; 
     FIG. 3 is a side view showing the snorkel in the proximity of a mouthpiece as partially broken away; 
     FIG. 4 is a sectional view taken along a line IV—IV in FIG. 3; 
     FIG. 5 is a view similar to FIG. 1, showing an alternative embodiment of the invention; 
     FIG. 6 is a side view showing an upper portion of the snorkel shown in FIG. 5 as partially broken away; 
     FIG. 7 is a perspective view showing the upper portion of the snorkel shown in FIG. 5 as partially broken away; and 
     FIG. 8 is a sectional view taken along a line VIII—VIII in FIG. 1, showing various embodiments (A)˜(D). 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Details of a snorkel according to the invention will be more fully understood from the description given hereunder with reference to the accompanying drawings. 
     FIG. 1 is a side view showing a snorkel  1  and a position of water surface W during actual use of the snorkel  1 . The snorkel  1  comprises a snorkel conduit  2  extending vertically of the figure and this snorkel conduit  2  has an upper opening  3  and a lower opening  4  provided, in turn, with a non-return valve  6  which will be described later in more detail. In the proximity of the lower opening  4 , a branch conduit  7  extends upward from the conduit  2  and an upper end of this branch conduit  7  forms a mouthpiece  9  provided with a pair of bit-projections  8 . 
     The snorkel  1  allows a swimmer to breathe through the mouthpiece  9  held in his or her mouth by means of the bit-projections  8  so that a quantity of air aspirated by the swimmer may be taken in through the upper opening  3  lying above the water surface W and a quantity of air expired by the swimmer may be forced out also through the upper opening  3 . A quantity of water having flowed into the snorkel  1  can be forced out through the upper opening  3  by instantaneous vigorous expiration of the swimmer. When the swimmer who has made a deep dive thereafter rises again toward the water surface W until the snorkel  1  restores its position as shown in FIG. 1, a quantity of water contained in the snorkel  1  which is now partially exposed above the water surface W has a pressure sufficient to open the non-return valve  6  and the quantity of water is purged out through the drainage opening  4 . A quantity of water remaining within the snorkel  1  is then forced out by the swimmer&#39;s expiration. 
     FIG. 2 is a perspective view of the conduit  2  in the proximity of the upper opening  3  as partially broken away. Within the conduit  2 , there is provided partitions  11  extending inwardly from the inner wall radially or parallel to one another and extending from the opening  3  longitudinally of the conduit  2  so that the partitions  11  may circumferentially compartmentalize an inner space of the conduit  2 . When a plurality of such partitions  11  are provided as shown, they may be formed so as to extend in parallel one to another longitudinally of the conduit  2 . The partitions  11  serve as baffle plates adapted to obstruct undesirable inflow of water, on one hand, and to rectify a stream of water forced out by expiration or a stream of fresh air taken in by aspiration of the swimmer both through the upper opening  3 , on the other hand. Breathing of the swimmer is thereby facilitated. 
     FIG. 3 is a side view of the snorkel  1  in the proximity of the mouthpiece  9  as partially broke away and FIG. 4 is a sectional view taken along a line IV—IV in FIG.  3 . The mouthpiece  9  includes a breathing seat  13  directly communicating with the branch conduit  7  and the inner wall of the conduit  2  facing the breathing seat  13  is formed with second partitions  12 . The partitions  12  extend inwardly from the inner wall radially or parallel to one another and also longitudinally of the conduit  2  so that they may circumferentially compartmentalize the conduit  2 . While there may be provided at least one second partition  12 , if it is desired to provide a plurality of such second partitions  12 , as shown, they may be arranged so as to extend in parallel one to another longitudinally of the conduit  2 . With the snorkel  1  having such second partitions  12 , the swimmer&#39;s vigorous expiration can efficiently force out a quantity of water contained within the conduit  2 . This is for the reason that a quantity of water remaining immediately below the breathing seat  13  can be rectified along the second partitions  12  without generation of any turbulence and rapidly moved toward the upper opening  3 . In this manner, the swimmer&#39;s expiration can be efficiently utilized to purge out the quantity of water and the swimmer&#39;s fatigue can be correspondingly alleviated. 
     The lower opening  4  at the bottom of the conduit  2  is provided with a non-return valve  6  mounted thereon from outside of the conduit  2 . The nonreturn valve  6  is made of a soft elastic material and adapted to be opened downwards. 
     FIG. 5 is a side view showing a snorkel  51  according to an alternative embodiment of the invention, FIG. 6 is a side view of this snorkel  51  in the proximity of the upper opening  3 , viewed as partially broken away, and FIG. 7 is a perspective view corresponding to FIG. 6 as partially broken away. Except for the portion in the proximity of the upper opening  3 , the snorkel  51  is similar to the snorkel  1  shown in FIG.  1 . The arrangement of the snorkel  51  in the proximity of the upper opening  3  is substantially the same as the arrangement disclosed in the previously mentioned Japanese Utility Model Registration Gazette No. 2536368. Specifically, the top of the conduit  2  is actually defined by a first tubular portion  53  and a second tubular portion  54  extending in parallel to the first tubular portion  53 , these tubular portions  53 ,  54  laterally communicate with each other via a passage  56 . The upper opening  3  comprises two openings  3 A,  3 B formed at upper and lower ends of the second tubular portions  54 , respectively, so that draft/purge can occur through both of these two openings  3 A,  3 B. The inner wall of the second tubular portion  54  is provided with a plurality of first partitions  11  extending inwardly from a region of the inner wall opposed to the passage  56  radially or parallel to one another and also longitudinally of the second tubular portion  54 . The first partitions  11  function not only to obstruct undesirable inflow water through the upper opening  3  but also to rectify a stream of water entering into the second tubular portion in the vertical direction and thereby to make it difficult for this stream of water to scatter toward the first tubular portion  53 . 
     The snorkel  51  shown is provided with the first partitions  11  adapted to obstruct undesirable inflow of water and the second partitions  12  adapted to improve a purge efficiency achieved by a swimmer&#39;s expiration. Therefore, both the first partitions  11  and the second partitions  12  are effective to alleviate the swimmer&#39;s physical fatigue. It should be understood, however, that the invention may be exploited in the form of the snorkel provided with either the first or second partitions alone. 
     FIG. 8 shows four embodiments (A)˜(D) of the first partitions  11  as viewed in the direction as indicated by arrows VIII—VIII in FIG.  1 . Of FIG. 8, (A) shows an embodiment in which a pair of sets each comprising a plurality of first partitions  11  are opposed to each other in the vertical direction, each set being parallelly arranged side by side in the horizontal direction as viewed in the figure; (B) shows another embodiment in which a plurality of first partitions  11  extend toward a center of the conduit  2 ; (C) shows still another embodiment in which there is provided a single slightly curved first partition  11 ; and (D) shows further another embodiment in which there is provided a single first partition  11  extending straightly toward the center of the conduit  2 . 
     The snorkel according to the invention can effectively alleviate a swimmer&#39;s physical fatigue by the first partitions adapted to obstruct undesirable inflow of water and by the second partitions which improve a purge efficiency achieved by the swimmer&#39;s expiration.