Underwater swimming apparatus
FIELD OF THE INVENTION 
     The present invention relates to an underwater swimming apparatus and, in particular, to an underwater swimming apparatus which makes it possible to freely swim underwater without scuba equipment or the like. 
     BACKGROUND OF THE INVENTION 
     Diving without any scuba equipment is restricted to short time periods during which people can hold their breath. 
     Diving using scuba equipment makes it possible to swim underwater for a long time. However, diving with scuba equipment requires much training and experience. Therefore, it is hard for people in general to dive or swim with scuba equipment. Therefore, in order to swim underwater or to obtain living space underwater, for example, a station or a dome is constructed underwater, and the interior of the dome is used as a living space. Further, Japanese Utility Model Unexamined Publication No. 49-17000 discloses an apparatus which can make it possible to swim and to behave in a desired manner in an underwater dome. The apparatus includes means for supporting the dome at a desired depth in the sea, a gate through which users can come into and go out from the dome, and means for supplying air of a pressure higher than the water pressure at such depth. However, such apparatus has a complicated construction and no known apparatus has been proposed yet which can easily and readily provide people with living space underwater. 
     SUMMARY OF THE INVENTION 
     An underwater swimming apparatus according to the present invention comprises a group of containers connected at a side wall thereof to each other in a stepped manner. Each of the containers opens downwardly, and notch means are provided at a lower portion of the side wall of each container to be connected to the next container. Means are provided for pumping air into a lowermost one of the containers, and means for supporting the containers are provided parallel to and spaced from the containers. Also means for anchoring the containers and the supporting means under water are provided. Air pumped from the pumping means remains in the space defined by the containers. Therefore, people can swim in the space without scuba equipment or the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be explained in detail hereinafter with reference to the accompanying drawings. 
     FIG. 1 is a perspective view showing an arrangement of the containers constituting an underwater swimming apparatus shown in FIG. 2; 
     FIG. 2 is a perspective view showing the underwater swimming apparatus according to one embodiment of the present invention; and 
     FIG. 3 is a side view showing a space in which people can swim. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the drawings, reference numeral 1 designates a cubic container, the bottom of which is opened. A plurality of containers 1 are connected to each other in a stepped manner so as to provide a group of containers 10 as shown in FIG. 1. Namely, the containers 1 are integrated into a container group 10 in which the containers are disposed in a stepped arrangement and connected at one side wall thereof to each other. Reference numeral 2 designates a notch formed at a lower portion of a side wall of each container 1. The lower portion is not connected to the next container, but the rest of the side wall is connected to the next one. Reference numeral 3 generally designates an air supply means communicating with the lowermost container 1. The air supply means 30 includes a compressor for pumping compressed air into the lowermost container 1 and a hose communicating at one end thereof with the compressor and at the other end thereof with the lowermost container 1. Reference numeral 4 designates a staircase disposed parallel to the container group 10. The staircase 4 is used as container supporting means and is spaced by a predetermined distance from the container group 10 through coupling members (not shown in FIG. 2) provided between the containers 1 and the staircase 4. Reference numeral 5 designates anchor means for anchoring the container group 10 and the staircase 4 under water. The anchor means 5 includes posts each of which is secured at a base end portion thereof on the bed of the sea and is connected at a distal end portion thereof to the container group 10 and the staircase 4 thereby anchoring them under water. 
     Operation of the apparatus constructed as above will now be described. 
     Firstly, the compressor is operated to pump air of a predetermined pressure level into the lowermost container 1. Air introduced into the lowermost container 1 passes through the notch into the next upper container 1 and then to a further upper container 1, one after another. Finally, the interior of all containers 1 is filled with air. Accordingly, a lower space of the container group 10 defines a living space filled with air in which people can swim. In the illustrated embodiment, since the staircase 4 is disposed at a predetermined spacing from the container group 10 and air is accumulated in the space defined within the containers of the container group 10, people can swim or otherwise use the area. The staircase 4 of the shown shape permits people to use the staircase 4, e.g., for standing up, sitting or the like. Furthermore, a diver can step down from the uppermost container 1 to the lower ones, one after another, so that he can thereby proceed to the deep sea without any scuba equipment or other air accumulator. 
     According to the present invention, there is provided an underwater swimming apparatus which is simple in construction and which can readily and safely provide a living space under water. Accordingly, the present invention is highly applicable for ocean leisure.