Abstract:
A ballast system for toy submarines comprises a plumbing device, a flexible bag, a piece of wire and a rod. The ballast system draws water in and forces water out by decompressing and compressing the flexible bag.

Description:
BACKGROUND OF INVENTION 
     Ballast systems which enable boats to dive and surface have been employed in real submarines, industrial submersibles and radio controlled submarines for professional modelers. In many of these cases, structural integrity at high pressure and precise volume control of the ballast tank are often required to operate the ballast system properly in hostile environment such as a deep sea. Therefore, they often require complicated and expensive structures. High pressure air or sometimes chemicals are used in these systems to pump water out of ballast tanks. When such systems are being used in toy submarines, they are not safe for children. 
     The present invention is intended for toy submarines which are to be operated in the bath tub, swimming pool, or other shallow water. Accordingly, several objects of my invention are to provide an easily manufacturable device which performs diving and surfacing maneuvers and is safe for children. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is an exploded front perspective view of the present invention. 
     FIG. 2 is a cross-sectional side view showing the operation of the invention when being used in surfacing the toy submarine. 
     FIG. 3 is a cross-sectional side view showing the operation of the invention when being used in diving the toy submarine. 
     FIG. 4 is an exploded front perspective view of the pressure hull. 
     FIG. 5 is an exploded front perspective view of the external hull. 
    
    
     DESCRIPTION OF DRAWING 
     1. Tube 
     2. Front Stop Plate 
     3. Wire 
     4. Flexible Bag 
     5. Rear Stop Plate 
     6. Mounting Bracket 
     7. Connecting Rod 
     8. Nuts 
     9. Bolts 
     10. Guiding Rod 
     11. Holes of the guiding rod 
     12. Electrodes of the chain driving unit 
     13. Holes 
     14. Chain 
     15. Sprocket 
     16. Chain Driving Unit 
     17. Batteries for the driving unit 
     18. External hull 
     19. Front External hull half 
     20. Rear External hull half 
     21. Pressure hull 
     22. Front pressure hull half 
     23. Rear pressure hull half 
     24. Electric wire pair for the chain driving unit 
     25. Propulsion motor 
     26. Electric wire pair for the propulsion motor 
     27. Batteries for the propulsion motor 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, the tube 1 and the flexible bag 4 form the main body of the ballast system. One end of the tube 1 is to be used as a nozzle for water to enter the system. The other end is fitted into the opening of the flexible bag 4. Adhesives, clamps, industrial processes can be applied to the overlapping area between the outer surface near the end of the tube 1 and inner surface of the opening of the flexible bag 4 to prevent water from leaking out of the ballast system. 
     A shielded wire 3 is glued spirally around the flexible bag 4. The wire is used to control the shape of the flexible bag 4. For example, it stops the flexible bag 4 from over expanding at deep water. It also forces the skin of the bag to be folded more properly when it is compressed. 
     The guiding rod 10 is longer than the flexible bag 4. The guiding rod 10 is installed inside the flexible bag 4. It is hollow inside and has holes 11 on its surface to allow water to enter or leave the ballast system more efficiently. One end of the guiding rod 10 is clamped to the end of the flexible bag 4 by the mounting bracket 6 and the connecting rod 7. The other end is inside the tube 1. When the flexible bag 4 is compressed or decompressed, the guiding rod 10 slides back or forth inside the tube to force the flexible bag 4 to move along the same direction as the length as the tube. A front stop plate 2 is mounted at about the junction of the tube and the flexible bag. A rear stop plate 5 is mounted at the end of the flexible bag 4 against the connecting rod. When the flexible bag is compressed, the folded skin of the flexible bag is confined in between the front stop plate 2 and rear stop plate 5. So water in the flexible bag can be emptied more completely. 
     A typical application of the ballast system in a toy submarine is illustrated in FIG. 2 and FIG. 3. The ballast system is installed inside the pressure hull 21 of a wire controlled submarine. The ballast system is driven by a chain drive system. The chain drive system comprises a chain 14, sprockets 15, and a chain driving unit 16. The electricity for the driving unit 16 is provided by the batteries 17 above the water through the electric wire pair 24. The direction of rotation of the sprockets 15 can be changed by switching the polarities of the batteries 17 which powers the chain driving unit 16. The holes 13 of the external hull 18 allow water to flood the external hull 18 freely. They also allow air inside the external hull to escape. 
     FIG. 2 shows the operation of the ballast system when submarine surfaces. Assume the weight of the submarine has been properly adjusted, so the amount of water displaced by the ballast system is enough to sink or surface the submarine. In FIG. 2, the flexible bag 4 is compressed and water is forced out of the flexible bag. The submarine becomes lighter than the water and floats. 
     FIG. 3 shows the operation of the ballast system when submarine dives. In FIG. 2, the flexible bag 4 is decompressed and water is drawn into the flexible bag. The submarine becomes heavier than the water and sinks. 
     The assembly of the submarine which employs the ballast system described above is illustrated in FIG. 4 and FIG. 5. FIG. 4 shows how the pressure hull 21 is assembled. The ballast system is installed inside the front half 22. The electric wire inside the rear half 23 is connected to the electrodes 12 of the chain driving unit 16. Then, depends upon the material of the front half 22 and rear half 23, both halves can be glued or welded together to form the pressure hull 21. FIG. 5 shows the final assembly of the submarine. Pressure hull 21 is glued inside the front half 19 of the external hull 18. Then, both front half 19 and rear half 20 are glued together to form the external hull 18 of the submarine. 
     Having described one specific embodiment of my invention, it is obvious that various modification and alterations may be made without departing from the spirit and the scope of the invention as defined in the appended claim.