Patent Publication Number: US-6220237-B1

Title: Compressed air toy gun

Description:
TECHNICAL FIELD 
     This invention relates to compressed air guns, and specifically to compressed air toy guns which fire a succession of projectiles. 
     BACKGROUND OF THE INVENTION 
     Toy guns which shoot or launch projectiles have been very popular for many years. These guns have been designed to launch projectiles in a number of ways. A common method of launching has been by the compression of a spring which propels the projectile upon its decompression or release, as, for example, with BB guns and dart guns. These guns however usually do not generate enough force to launch projectiles with great velocity. 
     Toy guns have also been designed which use compressed air to launch projectiles such as foam darts or balls. These types of guns use a reciprocating air pump to pressurize air within a pressure tank. In use, a single dart is loaded and the pump is typically reciprocated several times with each firing of the gun. Therefore, the gun must be loaded and pumped with each firing as it is not capable of firing several darts in rapid sequence. The rapid firing of a gun may be desired for those playing a mock war or other type of competition. 
     Today children who play mock wars often carry several guns at one time in order to fire several shots simultaneously or in rapid succession or carry a gun which is capable to firing several shots. Guns which may fire several shots in rapid succession typically include a magazine which holds the projectiles. However, the transfer of the projectiles from the magazine to the breach of the gun has been difficult to accomplish, especially wherein the projectiles are made of a soft, pliable material. The difficulty with the transfer of soft projectiles and the like has been the inherent tendency to deform under force rather than being guided by a force. As such, the projectiles often become stuck within the transfer mechanism or within the breach itself. 
     Accordingly, it is seen that a need remains for a toy air gun which may be fire a succession of projectiles from a magazine without the projectiles becoming lodged during the transfer between the magazine and the breach mechanism. It is to the provision of such therefore that the present invention is primarily directed. 
     SUMMARY OF THE INVENTION 
     In a preferred form of the invention a gun adapted to launch a projectile comprises an elongated launch tube having an longitudinal axis and sized and shaped to receive a projectile. The gun also has a moveable seal mounted within the interior of the launch tube sized and shaped to sealably engage a first portion of the projectile positioned within the launch tube and a stationary seal positioned within the interior of the launch tube adapted to engage a second portion of the projectile generally opposite the first portion. The stationary seal is adapted to allow reciprocal movement of the launch tube relative to the stationary seal while maintaining sealing engagement between the stationary seal and the launch tube. The launch tube, moveable seal and stationary seal define a firing chamber. The launch tube is moveable between a loading position and a firing position so as to vary the distance between the moveable seal and the stationary seal along the longitudinal axis of the launch tube to cause the moveable seal to sealably engage the projectile and capture the projectile between the moveable and stationary seals. The gun also includes means for providing a supply of compressed air to the firing chamber for launching the projectile from the launch tube. With this construction, the projectile is captured between the seals through relative movement of the moveable and stationary seals to each other which ensures sealing engagement of the projectile with the moveable seal during the transfer of compressed air into the firing chamber. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a compressed air gun embodying principles of the present invention in a preferred form. 
     FIGS. 2 and 3 are a sequence of side views, shown in partial cross-section, showing a portion of the air gun of FIG. 1, which show in sequence, the actuation of the launch tube and pump. 
     FIG. 4 is a top view of the magazine. 
     FIG. 5 is a schematic view of a compressed air gun in another preferred form of the invention. 
    
    
     DETAILED DESCRIPTION 
     With reference next to the drawings, there is shown a compressed air gun  10  having a stock or handle  11 , a launch tube  12  reciprocally mounted to the stock  11 , and a manual air pump  14 . The gun  10  has a pressure chamber  15  positioned within the launch tube  12  and a release valve  16  mounted within the pressure chamber  15  in fluid communication with the air pump  14  through a pressure tube  17 . The gun also includes a multi-projectile hopper or magazine  18  mounted for rotational movement upon the stock  11 . 
     The pump  14  includes a conventional cylinder  20 , a cylinder rod  21  terminating at a sealing head  19 , and a handle  22  mounted to an end of the cylinder rod  21 . The handle  22  has a flange  23  projecting upwardly. 
     The magazine  18  has a cylindrical outer shell  25  and an internal indexing wheel  26  positioned within the outer shell  25 , as best shown in FIG.  5 . The outer shell  25  includes a pivotal lid  27  and a bottom opening  28  extending to a loading tube  29 . The indexing wheel  26  has a central pivot hub  31  having an annular array of fins  32  extending therefrom which are coupled to an annular internal housing ring  33 . The central hub  31  is mounted to an indexer  35  having a rachet assembly  36  and a pneumatic drive  37  coupled to pressure tube  17  through a pressure tube  38 . The rachet assembly  36  has an angled toothed top plate  39  and an angled toothed bottom plate  40  sized and shaped to conform with top plate  39  and rotate relative to the bottom plate in only one direction. The bottom plate  40  is coupled to pneumatic drive  37  and a coil spring  41  which biases the bottom plate in a direction opposite to the force of the pneumatic drive  37 . 
     The pressure chamber  15  is fixedly mounted to the stock  11  and adapted to receive and store a supply of air at elevated pressure levels. The pressure chamber  15  has an exit opening  43  therein. The release valve  16  has a cylindrical manifold  45  and a cylindrical plunger  46  slidably mounted within manifold  45  in alignment with exit opening  43 . Plunger  46  has a gasket  47  to ensure sealing engagement of the plunger  46  about exit opening  43 . The pressure chamber  15  also includes an annular, O-ring type seal  48  which provides an air tight seal between the pressure chamber  15  and the interior of the launch tube  12 . In this embodiment the front wall of the pressure chamber may be considered part of a “seal” which seals off the launch tube. 
     The launch tube  12  has a top opening  50  sized and shaped to allow the passage of projectiles therethrough and a forward, annular, O-ring type seal  52  fixedly mounted to the interior of the launch tube in a location spaced forward of opening  50 . The launch tube  12 , pressure chamber  15  and seal  52  define a firing chamber  55 . The launch tube  12  also has slots therethrough through which extend portions of the pressure chamber and pressure tube  38  to allow unobstructed reciprocal movement of the launch tube as described in more detail hereinunder. A flange  54  sized and shaped to engage pump flange  23  depends from the front end of the launch tube  12 . A spring  56  extends between the launch tube and the stock so as to bias the launch tube forwardly. The launch tube  12  is adapted for reciprocal movement between a loading position shown in FIG. 2 and a firing position shown in FIG.  3 . 
     In use, an operator actuates the pump to pressurize a supply of air by grasping the handle  22  and moving the cylinder rod  21  rearwardly within the cylinder  20 . Pressurized air within the cylinder passes through pressure tube  17  into the manifold  45  of the release valve  16 . The pressurized air within the release valve manifold  45  causes the plunger  46  to move to a forward position sealing the opening  43 . Pressurized air then flows between the plunger  46  and the release valve manifold  45  so as to pressurize the pressure chamber  15 . A portion of the pressurized air passing through pressure tube  17  is diverted into pressure tube  38  and conveyed into the pneumatic drive  37 . With increased pressure within the pneumatic drive  37  the drive forces the rotation of the bottom plate  40 , which engages and causes the rotation of the top plate  39  against the biasing force of coil spring  41 . The movement of the top plate  39  in turn causes the rotation of the indexing wheel  26 , thereby bringing a projectile P in alignment with the opening  28  in the bottom of the magazine  18 . The projectile P drops downwardly through the opening  28 , through the loading tube  29 , and through the launch tube opening  50  so that the projectile P is positioned within the launch tube  12 , as shown in FIG.  2 . All references herein to directions are for purposes of clarity in reference to the drawings. 
     Continued movement of the pump handle  22  causes handle flange  23  to engage launch tube flange  54  and move the launch tube  12  from its loading position, shown in FIG. 2, to its firing position, shown in FIG. 3, against the biasing force of spring  56 . This rearward movement of the launch tube causes the forward seal  52  is engage the projectile P. This movement also causes the launch tube opening  50  to be positioned behind the pressure chamber seal  48  so that with the projectile sealably engaging the forward seal as the firing chamber  55  is sealed completely. 
     The final movement of the launch tube by the movement of the pump coincides with the maximum pressure of the pump, so that the passage of the pump sealing head  19  past the pump coupled to pressure tube  17  causes a release of air pressure within pressure tube  17  back into the pump cylinder. The release of air pressure causes the pressure valve plunger  46  to move to a rearward position unsealing opening  43 . With the unsealing of opening  43  pressurized air within pressure chamber  15  flows through opening  43 , into the firing chamber  55  of the launch tube. Pressurized air within launch tube propels the projectile P past the forward seal  52  and from the launch tube. The actuation of this type of release valve and air pump is described in more detail in U.S. Pat. No. 5,701,879 which is specifically incorporated herein. 
     Upon the release of pressurized air from pressure chamber  15  the pressurized air within pneumatic drive  37  is released through pressure tubes  38  and  17 . The release of air from pneumatic drive  37  causes the bottom plate  40  to be rotatably spring biased by coil spring  41  back to its initial position. As such, the bottom plate is again registered with the top plate  39  so as to initiate the next indexing movement of the magazine wheel  26 . 
     The return of the pump handle  22  to its initial, extended position, shown in FIG. 2, allows the spring biasing force of spring  56  to return the launch tube  12  to its initial, loading position. 
     It should be understood that the forward seal  52  causes enough resistance to not only insure a proper seal about the projectile but to momentarily delay the forward travel of the projectile so that there is a maximum build up of compressed air within the firing chamber of the launching tube. As such, as the projectile passes the forward seal there is a maximum force of air pressure within the launch tube to provide maximum distance of the projectile. 
     It should be understood that a pressure tank, alone or in addition to the air pump, may also be used to provide compressed air, as shown in FIG.  5 . Such an arrangement is also described in detail in U.S. Pat. No. 5,787,869 and U.S. patent application Ser. No. 08/822,008, which are specifically incorporated herein. As such, a gun may utilize a pump, a pressure tank, or the combination of a pump and pressure tank to provide a supply of compressed air. 
     While this invention has been described in detail with particular reference to the preferred embodiments thereof, it should be understood that many modifications, additions and deletions, in addition to those expressly recited, may be made thereto without departure from the spirit and scope of invention as set forth in the following claims.