Patent Publication Number: US-6904901-B2

Title: Air-powered projectile launcher

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention. 
   This invention relates to the field of small projectile launchers. More specifically, the invention comprises an air-powered launcher capable of individually feeding and shooting pliable objects such as marshmallows and foam ear plugs. 
   2. Description of the Related Art 
   Small projectile launchers have long been known as novelty items. These launchers typically fire potatoes, vegetable slices, marshmallows, tennis balls, and the like. Some are spring loaded, while others use pistons to compress a charge of air. They typically fire a small projectile which can be used in “mock combat” games without actually injuring the target. These devices have also found application other than as novelty items. Some have been used to fire marking projectiles in the veterinary and timber industries. Others have been used as pill injectors for treating horses and cows. Thus, although such projectile launchers are most often viewed as novelty items, their applications may be much broader. 
   BRIEF SUMMARY OF THE PRESENT INVENTION 
   The present invention comprises an air-powered projectile launcher. A double-acting piston within a pump tube is employed. A separate magazine tube is used to hold a plurality of projectiles. One end of the magazine tube feeds into a barrel assembly. The opposite end is closed by a one-way valve. The muzzle of the barrel is closed by a muzzle valve. When the piston is pulled through a back stroke, an air manifold directs the flow to induce a vacuum in the end of the magazine tube proximate the barrel. The vacuum closes the muzzle valve and opens the one way valve on the opposite end of the magazine tube. The vacuum then pulls the first projectile into the barrel. 
   When the piston is pushed through a forward stroke, pressure is directed behind the first projectile and in front of the second projectile. The second projectile is forced back into the magazine tube. The pressure within the magazine tube closes the one way valve, effectively making the second projectile the base of a closed firing chamber. As the piston continues through its forward stroke, the first projectile is forced through the barrel. The muzzle valve flies open and the first projectile shoots out at substantial velocity. The piston is then ready for a new back stroke, which repeats the cycle. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective hidden line view, showing the present invention. 
       FIG. 2  is an exploded detail view, showing how the barrel mounts to the manifold. 
       FIG. 3  is a section view, showing the barrel&#39;s internal details. 
       FIG. 4  is a section view, showing some internal passages. 
       FIG. 5  is a hidden line detail view, showing the connections to the piston. 
       FIG. 6  is a hidden line perspective view, showing the location of the one way valve. 
       FIG. 7  is a detail view, showing the loading of the magazine. 
       FIG. 8  is a section view, showing the firing cycle. 
       FIG. 9  is a section view, showing the firing cycle. 
       FIG. 10  is a section view, showing the firing cycle. 
       FIG. 11  is a perspective view, showing a variant having a detachable magazine. 
       FIG. 12  is a perspective view, showing the detachable magazine in more detail. 
       FIG. 13  is a perspective view with a section, showing how the magazine sealer can be detached from the magazine tube. 
       FIG. 14  is a section view, showing the internal details of the detachable magazine version. 
   

   REFERENCE NUMERALS IN THE DRAWINGS 
   
     
       
         
             
             
           
             
                 
             
           
          
             
               10 
               projectile gun 
             
             
               12 
               magazine tube 
             
             
               14 
               pump tube 
             
             
               16 
               slide 
             
             
               18 
               cross pin 
             
             
               20 
               pin slot 
             
             
               22 
               tube bracket 
             
             
               24 
               handle 
             
             
               26 
               manifold 
             
             
               28 
               barrel assembly 
             
             
               30 
               muzzle 
             
             
               32 
               muzzle valve 
             
             
               34 
               bore 
             
             
               36 
               breach receiver 
             
             
               38 
               piston 
             
             
               40 
               connecting rod 
             
             
               42 
               magazine outlet 
             
             
               44 
               one-way valve 
             
             
               46 
               barrel 
             
             
               48 
               breach plug 
             
             
               50 
               throat 
             
             
               52 
               air hole 
             
             
               54 
               feeding cone 
             
             
               56 
               pressure chamber 
             
             
               58 
               feeding tube 
             
             
               60 
               sealing ring 
             
             
               62 
               valve slot 
             
             
               64 
               follower 
             
             
               66 
               vent 
             
             
               68 
               feed plenum 
             
             
               70 
               projectile 
             
             
               72 
               first projectile 
             
             
               74 
               second projectile 
             
             
               76 
               retaining clip 
             
             
               78 
               detachable magazine 
             
             
               80 
               magazine sealer 
             
             
               82 
               magazine receiver 
             
             
               84 
               one piece barrel 
             
             
               86 
               sealing ring 
             
             
                 
             
          
         
       
     
   
   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a hidden line view of projectile gun  10 . Magazine tube  12  and pump tube  14  are held in position by manifold  26  and tube bracket  22 . Slide  16  slide forward and backward along pump tube  14 . Cross pin  18 —which is connected to an internal piston, rests within pin slot  20 . Pin slots the forward and backward travel of slide  16 . 
   Handle  24  is provided on the lower portion of tube bracket  22 . Barrel assembly  28  is attached to manifold  26 . Muzzle  30  is regulated by muzzle valve  32 . The projectiles to be fired by the device are stored in magazine tube  12 . The user charges the device by pulling slide  16  to its rearward limit. When the user then pushes slide  16  forward, a projectile will be expelled from muzzle  30 . Each cycling of slide  16  loads and fires a single projectile. 
     FIG. 2  shows barrel assembly  28  removed from manifold  26  and in an exploded state. Breach plug  48  fits into breach receiver  36 , with sealing ring  60  forming an airtight seal. The forward end of magazine tube is open (magazine outlet  42 ). Barrel  46  threads onto the forward portion of breach plug  48 . Muzzle valve  32  is pivotally mounted to barrel  46 . 
     FIG. 3  is a section view through breach plug  48  and barrel  46  (with the two components being assembled). Referring to both  FIGS. 2 and 3 , magazine outlet  42  fits inside breach plug  48 , adjacent to feeding cone  54 . The projectiles are fed through this assembly from right to left in the view as shown. Feeding cone  54  narrows to feeding tube  58 . Feeding tube  58  leads into pressure chamber  56 . Pressure chamber  56 , in turn, leads to throat  50 . Bore  34  is connected to throat  50 . 
   The two components are threaded together, though the actual method of joinder is not significant. A series of radially spaced air holes  52  pass through breach plug  48 . These apply pressure and vacuum forces to pressure chamber  56 , as will be described subsequently. Valve slot  62  is provided to attach muzzle valve  32 . 
     FIG. 4  is a section view through the assembled projectile gun. The reader will observe how breach plug  48  fits within manifold  26 . The forward end of pump tube  14  is sealed by manifold  26 . Vent  66  is cut into the top of pump tube  14 , however. Vent  66  feeds into feed plenum  68 , a hollow cavity within manifold  28 . Returning briefly to  FIG. 2 , feed plenum  68  is readily visible. Breach plug  48  actually seats against a step-down in the bore through manifold  26  (visible as a ring in FIG.  2 ). The reader will observe that feed plenum  68  completely surrounds magazine tube  12 . 
   Returning now to  FIG. 4 , the purpose of air holes  52  will be explained. Piston  38  moves forward and backward within pump tube  14 , since it is connected to slide  16 . As it moves forward, air is pushed through vent  66  into feed plenum  68 . It then flows through air holes  52  and pressurizes pressure chamber  56 . The reverse is also true—When piston  38  moves backward, a vacuum is created within pressure chamber  56 . 
   Follower  64  is a free-sliding plug within magazine tube  12 . The rearward end of magazine tube  12  is closed by a one-way valve which allows air to flow into, but not out of, the rear of magazine tube  12 . 
     FIG. 5  illustrates the connections between slide  16  and piston  38 . Piston  38  is attached to connecting rod  40 . Connecting rod  40  is pierced by a transverse hole, as is slide  16 . Cross pin  18  is located in the transverse hole through connecting rod  40  and slide  16 . It is retained via friction, adhesive, clips, or other known devices. Cross pin  18 , as mentioned previously, also rests within pin slot  20 . Thus, when the user graps slide  16  and moves it forward or backward, piston  38  will move likewise. 
     FIG. 6  shows a rear view of projectile gun  10 . Tube bracket  22  is used to mount one-way valve  44 , which closes off the rear end of magazine tube  12 . 
     FIGS. 7-10  illustrate the operation of the device. In  FIG. 7 , barrel assembly  28  has been removed to expose magazine outlet  42 . One or more projectiles  70  are pushed into magazine outlet  42  and into magazine tube  12 . Projectiles  70  should be somewhat pliable. Small marshmallows and foam ear plugs are good examples of suitable projectiles. 
   Once the desired number of projectiles has been loaded, the user replaces barrel assembly  28  as shown in FIG.  8 . Barrel assembly  28  may be fitted by simply pressing it into manifold  26  (conventional latching features may also be used to retain it). Follower  64  lies to the rear of projectiles  70  within magazine tube  12 . 
   To prepare the device for firing, the user first grabs slide  16  and pulls it rearward.  FIG. 9  shows this action, with piston  38  nearing the end of its rearward stroke. A vacuum is created within the forward portion of pump tube  14 . This vacuum is carried through vent  66 , feed plenum  68 , air holes  52 , and into pressure chamber  56 . The vacuum pulls muzzle valve  32  closed. One-way valve  44 , in the rear of magazine tube  12  opens to admit air into the magazine tube, behind follower  64 . Follower  64  then moves forward, pushing the projectiles along, until first projectile  72  is lodged in throat  50  (It is stopped by the narrowing diameter of throat  50 ). Second projectile  74  rests within feeding tube  58 . 
     FIG. 10  shows the forward stroke of piston  38 . High pressure is created within pressure chamber  56 . This pressure forces second projectile  74  back into feeding tube  58  (using all the remaining projectiles against follower  64 ). One-way valve  44  will not allow air to escape from the rear of magazine tube  12 . Thus, the remaining projectiles and follower  64  effectively become a rearward wall of pressure chamber  56 . Since the pressure has nowhere else to go, first projectile  72  is compressed into throat  50  and down bore  34 . Air compression in front of first projectil  72  opens muzzle valve  32 . First projectile  72  then shoots out at considerable velocity. 
   Once piston  38  reaches the forward limit of its stroke, the cycle is set to repeat. When the piston is again cycled rearward, the configuration shown in  FIG. 9  will recur. Thus, those skilled in the art will realize that each cycle of the piston, shoots one of the projectiles in magazine tube  12 . 
   The loading process illustrated in  FIG. 7  is effective but not very rapid. Some users may desire the immediate reloading of a full magazine.  FIG. 11  depicts a variant including a detachable magazine. Manifold  26  is modified to include magazine receiver  82 . Detachable magazine  78  includes magazine sealer  80  affixed to its forward extreme. Detachable magazine  78  is loaded with projectiles. A follower  64  and one-way valve  44  are also provided. 
   To reload the device, the user presses the forward end of detachable magazine  78  into magazine receiver  82  and rotates the rearward end down into retaining clips  76  provided on the top of tube bracket  22 . Magazine sealer  80  provides an airtight seal with manifold  26 . The internal passages and connections within manifold  26  may be the same as illustrated previously, though the dimensions will vary to accommodate the addition of magazine sealer  80 . 
   Thus, to reload the weapon, the user attaches detachable magazine  78 . The user may need to cycle slide  16  to advance the first projectile to firing position. The user then fires the device normally. Several detachable magazines  78  can be carried for quick reloading. 
   Although the preceding descriptions contain significant detail they should not be viewed as limiting the invention but rather as providing examples of the preferred embodiments of the invention. As one example, vent  66  could be configured to feed directly into pressure chamber  56  rather than through feed plenum  68 . The principles governing the operation of the device would be the same.  FIGS. 12-14  depict this variation (also including the use of a detachable magazine and a one-piece barrel assembly).  FIG. 12  shows detachable magazine  78  in more detail. It includes a feed tube with one way valve  44  closing one end. Magazine sealer  80  is removably mounted on the opposite end. Magazine sealer  80  includes a pliable sealing ring  86 , which seals the assembly to magazine receiver  82  in manifold  26 . 
   In order to allow quick loading of detachable magazine  78 , magazine sealer  80  is detachable.  FIG. 13  shows the assembly with magazine sealer  80  detached. Magazine outlet  42  is exposed for rapid loading. Magazine sealer  80  is sectioned in the view to allow the visualization of its internal features. The reader will observe that it includes internal features previously found in breach plug  48  (feeding cone  54  and feeding tube  58 ). 
     FIG. 14  shows detachable magazine  78  in position within the projectile launcher, with a section through the assembly to expose the internal details. Breach plug  48  has been eliminated. Vent  66  feeds directly into the area immediately behind one piece barrel  84  (pressure chamber  56 ). The linear progression through feeding cone  54 , feeding tube  58 , pressure chamber  56 , throat  50 , and bore  34  is the same as for the previously disclosed embodiments. Thus, the function of feeding and firing the projectiles is identical. However, the device has been simplified. It also permits the use of a detachable magazine. 
   Those skilled in the art will realize that many such structural variations are possible without altering the operating principles of the invention. Accordingly, the scope of the invention should be determined by the following claims, rather than the examples given.