Abstract:
A reusable special effects audible and visual fireball generator device which comprises a cylindrical main housing having end caps mounted at each end. A gas container is positioned within the housing and a knife blade is mounted within the housing adjacent one end cap. A holder containing a predetermined amount of black sporting powder is secured within the housing adjacent the other end cap. When the black sporting powder is ignited, the gas container is forced against the knife blade, rupturing the tank. The released liquid gas mixes with air and the black sporting powder igniting the mixture and providing a fireball effect.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   A reusable device for producing a safe and consistent sized gas fireball effect for various non-destructive device uses. 
   2. Description of the Prior Art 
   Devices for producing fireballs have been available in the prior art. The typical prior art device comprises black powder contained in a cardboard cup, capped and wrapped tightly with tape and placed on a fuel source such as gasoline, in a non-metal container. 
   The prior art fireball generators have at least one important limitation; once ignited, the device can not be reused. 
   What is desired is to provide a device for producing a gas fireball using a commercially available gas bottle, many of the device components being recoverable, and thus reusable after generation of the fireball. 
   SUMMARY OF THE INVENTION 
   A fireball generator device comprising a steel cylindrical main housing having first and second threaded end caps, a gas containing tank being positioned within the interior of the housing. A plastic cup is attached to the second threaded end cap and a small electric igniter is placed through a hole formed in the cup. Electric igniter lead wires are positioned on the outside of the housing. The cup is then filled with black sporting powder and a cap is secured to the cup to contain the powder. The device is then placed where the fireball is to be generated and the main electric battery wires are connected to the igniter wires exiting the housing end cap. When conditions are safe, the igniter inside the cup is ignited via a battery or blasting machine. 
   The powder then explodes within the cup, the resulting high pressure and temperature gases melting the cup so that it disengages from the cap and pushing the cup up against the top of the LPG tank (or a same sized tank having an equivalent ignitable type gas) forcing it forward at a high rate of speed. The gases are contained within a small area around the top of the tank to provide maximum gas pressure by using a steel insert sleeve that is adjacent to the outside diameter of the tank. As the tank moves forward, the gas pressure safely escapes through a series of patterned holes formed around the circumference of the housing releasing the built up pressure. At this time, the bottom of the tank slams into a puncture mechanism having a portion thereof set inside slots formed at one end of the housing. The mechanism rips open the tank bottom, instantaneously releasing the liquid gas from the tank. The gas released from the tank is vented to the outside of the pipe through the patterned holes and mixes with air, the black sporting powder igniting the tank gas and creating a fireball. 
   To reuse, the user opens the second end cap and replaces the tank, black powder cup, cap and igniter and starts the process over again. The first and second end caps and cylindrical housing, both preferably fabricated from steel, are cold to the touch immediately after the fireball due to the liquid gas being expelled from the vented holder. Since the fireball lasts between 1 and 3 seconds, the steel end caps and cylindrical housing remain relatively cool and thus not heat damaged, allowing these components to be reused. 

   
     DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention as well as other objects and further features thereof reference is made to the following description which is to be read in conjunction with the accompanying drawing therein: 
       FIG. 1  is a perspective view of the fireball generator device of the present invention illustrating the 360 degree hole pattern; 
       FIG. 2  is a side plan view of the device shown in  FIG. 1 ; 
       FIG. 3  is one end view of the device shown in  FIG. 1 ; 
       FIG. 4  is the other end view of the device shown in  FIG. 1 ; 
       FIG. 5  is a cross-sectional view along line  5 - 5  of  FIG. 2 ; 
       FIG. 6  is a cross-sectional view taken on line  6 - 6  of  FIG. 5  showing the blade therein; 
       FIG. 7  is a cross-sectional view along line  7 - 7  of  FIG. 5  showing the four centering screws for the gas cylinder; 
       FIG. 8  is a cross-sectional view along line  8 - 8  of  FIG. 5  showing the notches in the housing to support the blade; 
       FIG. 9  is a cross-sectional view along line  9 - 9  of  FIG. 5  showing the sharpness of the blade; 
       FIG. 10  is a cross-sectional view along line  10 - 10  of  FIG. 5  showing the 360 degree hole pattern; 
       FIG. 11  is a cross-sectional similar to  FIG. 5  showing the device after the explosive has exploded and driven the gas bottle into the blade; 
       FIG. 12  is a perspective view of the fireball generator device showing a different hole pattern formed in the surface of the housing; 
       FIG. 13  is a side plan view of the device shown in  FIG. 12 ; and 
       FIG. 14  is a cross-sectional view along line  14 - 14  of  FIG. 13  showing the different hole pattern. 
   

   DESCRIPTION OF THE INVENTION 
   Referring now to the  FIGS. 1-11 , a first embodiment of the fireball generator device  10  of the present invention is illustrated (device  10  is essentially identical to the device embodiment shown in  FIGS. 12-14  except that the housing hole patterns are different). Fireball generator  10  comprises main housing cylinder  12 , preferably made of steel, and threaded end caps  14  and  16  also preferably made of steel. Cylinder  12  has slots  13  ( FIGS. 6 and 8 ) formed in the end adjacent end cap  14  and a cutout  15  formed about the interior circumference of cylinder  12  adjacent end cap  16  as shown in  FIG. 5 . End caps  14  and  16  screw onto threads  19  formed on the ends of housing  12  as illustrated in  FIG. 5 . End caps  14  and  16  have a plurality of rib members  20  extending in a radial direction from the surface of the end caps, the rib members providing better gripping and turning features for a user and preventing device  10  from rolling around on the ground after device positioning. A plurality of venting holes  22  are formed around the entire circumference of housing cylinder  12  (360° pattern is illustrated). As shown in  FIG. 5 , a liquid propane (LP) tank  24  (or a same sized tank having an equivalent ignitable type gas, such as MAPP gas) having liquid propane gas  27  therein is positioned with the hollow interior area  28  of housing  12 . Four guide screws  32  ( FIG. 7 ) equispaced around the circumference of housing  12  secure and align tank  24  in place within interior area  28 . A plastic cup  34  is positioned within a insert pipe sleeve  30 , pipe sleeve  30  limiting, or reducing, gas generated when the black sporting powder placed in cup  34  is ignited. Pipe sleeve  30  slides into housing  12 , stops at its shoulder and mates with cutout  15 . The outside diameter of sleeve  30  is less than the inside diameter of housing  12  so that sleeve  30  can easily slide into housing  12  without the user having to exert undue force. Cutout  15  prevents the sleeve  30  from dropping down the housing to the other end. The user removes sleeve  30  by reaching inside and pulling it out from housing  12 . An electric igniter is placed inside cup  34  and the igniter wires extend through a hole  40  formed in threaded end cap  16 , the hole being sealed with clay or glue. A predetermined amount of black sporting powder  29  is poured into cup  34  (cup  34  is designed so that the user can not overfill the cup with black sporting powder which would create a dangerous condition) and then covered with threaded cap  42 , cap  42  screwing inside of steel end cap  16 . Cap  34  and cup  42  can either be pressed fit together and glued or screwed together (and glued if necessary). As will be explained hereinafter, the igniter, cup  34  and cap  42  are replaceable items. Cup  34  has a threaded recess well  41  to engage the threaded boss formed on the tank end preventing the tank  24  from moving if the device  10  itself is moved or repositioned. 
   A knife blade  50  having a triangular shaped protruding member  51 , a sharp tip portion  52  and shoulders  59  is positioned in a manner such that flange ends  53  are positioned within end cap  14  and shoulders  59  slide into slots  13  formed in one of the threaded ends of housing  12 . Shoulders  59 , when inserted into slots  13 , enable knife blade  50  to be correctly aligned inside housing  12 . 
   Starting with the housing cylinder  12  and end caps  14  and  16 , in order to fabricate the fireball generator of the present invention, a user unscrews the steel pipe main housing end cap  16  and then inserts tank  24  into the main housing  12 . Tank  24  is positioned such that threaded boss  37  on the end of tank  24  screws into the threaded well  41  formed in cup  34 . A small electric igniter (typically 12′ long) is placed into the cup receptacle, the electric igniter lead wires (the part that hooks to a power source—battery, etc.) extending through a hole formed in plastic cap  42  and then through hole  40  formed in threaded cap  16 . Device  10  is then moved to a predetermined area and long battery wires are connected to the igniter wires exiting pipe end cap  16 . When all conditions are safe, the igniter inside cup  34  is activated via a battery or blasting machine. 
   The black sporting  29  powder explodes within cup  34  (see  FIG. 11 ) melting the coupling between cup  34  and cap  42  and the high pressure gases pushes cup  34  against the top of the tank  24  forcing it forward at a high rate of speed. The gases are contained within a small area around the top of tank  24  to provide maximum gas pressure by using steel insert sleeve  30  positioned adjacent to the exterior wall of tank  24 . As the tank  24  moves forward a few inches, the gas pressure safely escapes through a series of venting holes  22  formed around the housing circumference releasing the built up pressure. At this time, tank  12  slams into the knife blades  50  set inside the bottom of steel pipe cap end  14 , ripping open the bottom of tank  24  and releasing gas  27 . The gas is vented to the outside of the pipe  12  through the holes  22 . At the same time gas  27  is released, it mixes with air and the black sporting powder, igniting the liquid gas and creating a consistent and predictable fireball. 
   To reuse, steel end cap  16  is opened and the tank  24 , the cup  34  and cap  42  are replaced and the process started over again. Note that the knife blade  50  can be used over many times until it needs to be replaced. Mechanisms other than knife blade  50  can be used to rip open the bottom of tank  24 , such as a steel punch. 
   Igniter components other than black sporting powder can be utilized with the fireball generator device of the present invention. For example, high pressure, inert gases such as dry nitrogen can be utilized. If this is the case, a different technique is necessary to ignite the liquid gas. For example, an electric pyrotechnic spark would ignite the released liquid gas when the tank is ruptured. Alternately, a flint can be designed into housing  12  so as the tank  24  is moving into the knife blade  50 , it rubs the flint causing a spark to ignite the gas. 
     FIGS. 12-14  illustrate a second embodiment of a fireball generator, fireball generator  60  comprising a housing  12 ′ wherein the series of patterned holes  22 ′ is formed approximately 180° around the circumference of housing  12 . Other than this differing hole pattern, the configuration of device  60  is identical to device  10 . 
   The device of the present invention is not designed to be a weapon or destructive device and thus provides a simplified and economical device for generating an audible and visual fireball effect that provides a safe, consistent and predictable sized fireball effect for use within the entertainment industry and as a training aid for law enforcement, fire departments and other governmental agencies, the military and companies engaged in the business of security training. 
   While the invention has been described with reference to its preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its essential teachings.