Patent Document

CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/249,525, filed Nov. 17, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     a. Field of the Invention 
     This invention relates, in general, to the field of paint ball guns and in particular to adaptor apparatus for securely mounting a paint ball hopper to a paint ball gun, which apparatus provides for rapid attachment and removal while providing for positive attachment. 
     b. Description of the Prior Art 
     A paint ball gun, in general, comprises three main components: a gun portion, a propellant portion and a hopper. The hopper contains a plurality of encapsulated paint balls, which, in general, are fed by gravity or gravity plus an assisting mechanism into the gun portion. The propellant portion provides the means to propel the paint ball out of the gun. The propellant portion and the gun portion are securely attached to each other, while the hopper is initially securely attached to the gun at a location above the gun portion. The hopper is fitted and attached to the paint ball gun by use of a prior art tube extending from the hopper, which is “press fitted” into a cylindrical opening in the gun, or is press fitted in a tube, which is threaded into the gun. In operation, a number of paint balls are loaded into the hopper through an opening at the top of the hopper, the paint balls are fed from the hopper into the gun and then discharged out of the nozzle by compressed gas. The ability to remove and reconnect a hopper is routine for a number of reasons, including but not limited to cleaning a hopper, trouble shooting the passage of paint balls from the hopper into the gun, for storage, for preventative maintenance procedures and other like operations. 
     The prior art press fit of the hopper to the gun thereby allows convenient removal and replacement a hopper; but, because the hopper is frequently removed from the gun and reattached, the initial tight fit becomes looser and looser, to an extent that the hopper will not stay in position on the gun. Typically, a person attempting to remove a hopper will employ a combination of twisting and side-to-side pulling motions until the hopper comes off. Understandably, such twisting and side to side pulling eventually causes the press fit to become a loose fit such that the hopper can become disengaged from the gun when no disengagement is desired. Moreover, such unintentional disengagement of the hopper from the gun can occur at the most inopportune times. For example, when an person is running which causes the gun to jump up and down, or when a person “hits the dirt” in going from a run to lying prone on the ground to either fire the paint ball gun or to take cover. When the hopper inadvertently becomes disengaged from the gun, the gun is inoperable which is not at all satisfactory. Further, when the press fit becomes too loose, a new hopper may be required which adds an unnecessary expense and inconvenience to persons participating in the sport associated with paint ball guns. 
     What is needed then, is attachment apparatus between the hopper and the gun that forms a tight connection, which does not loosen as a result of removing or replacing hoppers, forms an effective seal, and provides for rapid attachment and disengagement of the hopper when the gun is being used in the field or elsewhere and without tools. 
     The present invention simply and effectively provides the solution to these prior art problems. 
     SUMMARY OF THE INVENTION 
     The above objects as well as others are accomplished by the present invention which comprises adaptor apparatus that fits between a hopper of a paint ball gun and the gun itself. In one preferred embodiment, the adaptor apparatus is attached at one end, to either the hopper or the gun, while the other end is compression fitted to the other of the gun or the hopper. In accordance therewith, one end of the adaptor is threadingly connected to the gun and the other end utilizes a compressing device in association with a radially compressible bushing that is compressed onto a tube extending from a bottom of the hopper. The compression connection provides for the quick connect and removal of the hopper without the need for tools. 
     In accordance with the above, there has been summarized some of the more important features of one embodiment of the present invention in order that the detailed description of the invention as it appears in the below detailed description of the same, may be better understood. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, in which: 
     FIG. 1 is a schematic representation of a typical prior art paint ball gun to which the adaptor of the present invention may be applied; 
     FIG. 2 illustrates a partial portion of the paint ball gun of FIG. 1 to which the inventive adaptor has been applied; 
     FIG. 3 illustrates one embodiment of the compressible bushing of FIG. 2; 
     FIG. 4 illustrates another embodiment of the compressible bushing of FIG. 2; 
     FIG. 5 illustrates a one piece bushing and adaptor tube according to the present invention; and, 
     FIG. 6 illustrates yet another embodiment of the present invention that eliminates the use of a separate adaptor tube. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. Therefore, specific structural and functioning details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     Reference is now made to the drawings, wherein like the characteristics and features of the present invention shown in the various figures are designated by the same reference numerals. 
     Referring now to FIG. 1, a typical paint ball gun includes a gun portion  11 , a hopper portion  12  and a propellant portion  13 . As noted above, the propellant portion and the gun portion are securely connected together and are occasionally intended to be disengaged from each other such as when the propellant tank needs to be replaced. The hopper portion  12 , on the other hand, is intended to be securely attached to the paint ball gun, but somewhat readily disengaged from the gun on a routine basis for sundry reasons such as cleaning, performing maintenance, trouble shooting the feeding of paint balls from the hopper into the gun, etc. In operation, paint balls are loaded into the hopper  12  and then individually funneled into the gun  11 . Pulling the trigger causes the propellant to expel a single paint ball from the gun in the direction in which the gun is aimed. As the supply of paint balls in the hopper diminishes, the hopper is or can be refilled with additional paint balls. 
     The connection of the hopper to the gun, in the prior art comprises a male-female arrangement where a tube at the end of the hopper extends downward and is press fitted into an opening in the top of the gun, or the end of the hopper is press fitted into a tube that is threadingly attached to the gun. The tube is relatively large, for example three quarters of an inch or more, such that a standard paint ball can pass through the tube and into the gun. The tube thereby comprises a passage through which the paint balls contained within the hopper are transferred or fed into the gun. This type of connection, as explained above, initially provides for a sufficiently tight connection, which is needed to support the G-forces caused by the weight of a loaded hopper when the gun is rapidly moved from one position to another, such as when the person using the gun is running or falling down, but after a number of disengagements, the press fit becomes loose and the hopper can readily fall off the gun. 
     FIG. 2 shows, in cross section, the details of one embodiment of the inventive connecting adaptor  10  as it is positioned between the outlet tube  29  of a hopper  12  and the inlet opening  17  to the gun  11 . In this embodiment, the inventive adaptor includes a tubular member  14 , a bushing member  23  (which may also be referred to as a compression member), and a nut  20 . The lower end of the tubular member  14  is threadingly attached  15  to the inlet opening  17  of gun  11 , or is press fitted into opening  17 . Although not necessary to the invention, a ledge  19  at the lower end of tubular member  14  seats against a corresponding surface on the gun  11  at the entrance of opening  17  to provide a firm and stable platform when tubular member  14  is fully threaded or press fitted into opening  18 . 
     A type of a variable force, slip-fit connection connects the upper end of the tubular member  14  to the outlet tube  29  of the hopper  12 . The bushing  23 , which is compressible in an inwardly, radial direction, is positioned within a nut  20  and above the upper end of tube member  14  and in axial alignment therewith. For convenience of assembly and disassembly, the bushing can be non-permanently attached to the nut by means of a small lip extending from the bushing that mates with a groove in the inside of the nut. The nut  20  fitting over bushing  23  includes a flange  22  positioned at the upper edge of bushing  23 . The upper end of tube  14  and the lower end of nut  20  are threadingly connected  21  such that tightening of the nut  20  causes flange  22  to bear down on bushing  23 , while the upper end of tube member  19  bears up against the bushing  23 , resulting in radial compression of bushing  23 . As the tightening force of nut  20  increases, the bushing  23  continues to decrease in diameter until such time as it fits tightly up against the outer circumference of the hopper outlet tube  29 . In this manner, one end of the inventive adaptor  10  is fly and securely attached to the hopper  12  and the other end of the inventive adaptor is firmly and securely attached to the gun  11 . 
     In order to disengage the hopper  12  from the gun  11  all that is required is to loosen nut  20  which allows bushing  23  to return to its original uncompressed size thereby releasing the force against the outer circumference of hopper tube  29  which allows the hopper  12  to be pulled out of the top end of the adaptor  10  with relative ease and without the need to forcefully pull and twist the hopper. The attachment of the lower end of the adaptor  10  to the gun  11  is not disturbed during the disengagement procedure and therefore, neither a threaded connection or a press fit connection will become loose. 
     In FIG. 3, it is seen that bushing  23  comprises a cylindrical member having an inner surface  24 , an outer surface  25 , a top surface or edge  26 , a bottom surface or edge  27 . A single opening  31  through the wall of the bushing extending from the upper edge  26  to the lower edge  27  is provided to allow the bushing to compress in diameter. The outer surface  25  of bushing  23  is dimensioned to have a diameter slightly less than the diameter of the inner surface  28  of nut  20 . The length of compression member  23  is dimensioned to fit within the axial space formed between the flange  22  and the upper end  32  of tubular member  14  when nut  20  is partially threaded onto tubular member  14 . A different version of the non-permanent attachment of the bushing to the nut is shown in FIG.  3  and comprises the protruding lip extending from the upper end of the bushing and a corresponding groove (not shown) in the nut. 
     The lower end surface  27  of bushing member  23  is tapered and fits against the upper end  32  of tube member  14  which end  32  is also tapered. The upper end surface  26  of compression member  23  and the inner surface of flange  22  are also tapered. The diameter of the inner surface  24  of bushing  23  is sized to be slightly greater than the outer diameter of the tube portion  29  extending downward from hopper  12 . For convenience during engagement and disengagement of the hopper, the bushing is held in place within nut  20  by means of an annular ledge around the bushing and a small annular groove in the inside of nut  20 . 
     When a hopper  12  is to be attached to a gun  11 , nut  20  is tightened such that the flange  22  of nut  20  and the upper edge  32  of cylindrical member  14  begin to contact the upper and lower ends  26  and  27  of compression member  23 , respectively. The lower end of hopper tube  29  is then inserted into the bushing  22  for an appropriate distance. The uncompressed size of bushing  22 , as described above, allows for easy insertion of the hopper tube  29  into the bushing  22 . When tightening of nut  20  continues, compression member  23  compresses inwardly, first taking up the small space between the inner diameter of the bushing  23  and the outer diameter of the hopper tube  29 , and then applies a compressive force to the outer diameter of the tube  29  which results in a firm and secure connection of the hopper  12  to the gun  11 . To remove a hopper  12  from a gun  11 , it is a simple matter to loosen nut  20  which allows bushing  21  to expand to its original size recreating the clearance space between the bushing  23  and the hopper tube  29 , thereby allowing the hopper tube  29 , and the hopper  12  attached thereto, to be removed. 
     In addition to the configuration described above, bushing  23  can take on many configurations, any of which will satisfactorily serve its intended purpose of bearing against the hopper tube  29  and thereby form a secure fit between the hopper and the gun and yet provide a fit that is easily taken apart. FIG. 4 depicts another configuration of the bushing  23 . In this embodiment, there is provided a plurality of openings  33  that extend through the wall and along the axial length of the bushing. However, the openings initiate from alternate ends of the bushing and stop prior to reaching the other end of the bushing. Rather than decrease the overall diameter of the bushing as in the embodiment of FIG. 3, tightening of the nut  20  serves to cantilever the portions  34  of the bushing between the openings  33 , at the upper and lower ends of the bushing, inward toward the hopper tube  29 . The inward motion being caused by the action of the mating tapered edges of the bushing and the nut, and the bushing and the upper edge of the tube member  14 . Other configurations of the openings vis-a-vis the bushing can be readily be envisioned by a person having ordinary skill in the field, which other configurations are intended to be included within the scope of the present invention. Then too, the bushing can be made from a soft rubber or plastic material such that the inward compression caused by the tightening of the nut  20  is accomplished by the inherent compressibility of the material from which the bushing is made. With a soft rubber or plastic bushing, therefore, no openings may be required. 
     Modifications to the tapered ends of the bushing  23 , the edge of the tube member  14 , and the flange  22  of nut  20  to cause inward movement of the bushing  23  can also be readily be envisioned by a person having ordinary skill in the field, which other modifications are intended to be included within the scope of the present invention. For example, the tapered edges on the bushing can be located on the outer circumference of the bushing. Further, the taper on the flange  22  of nut  20  can be eliminated, and/or the taper on the upper end of bushing  23  can be eliminated. Thus, only the taper on the bottom of the bushing  23  and the taper on the top of the tube member  14  serve to radially compress bushing  23 . While such a configuration will work as intended, it may not be as efficient as the embodiment of FIG.  2 . Of course, the angle of the taper and the location of the same are a matter of choice of design. 
     FIG. 5 illustrates an embodiment of the present invention where the tube member and the bushing are combined in one piece, which will be referred to as the compressible tube member  5  The compressible tube member includes a tube portion  36  and a bushing portion  37  The bushing portion  37  includes one or more openings  38  that extend from the upper edge to a location slightly above the threads  39 . Threads  39  serve the same function as in the previous embodiments, i.e. provide for the attachment of the nut  20  which when tightened, forces the upper portion of bushing portion inward and tight against the outer circumference of hopper tube  14 . The one-piece compressible tube member  35  will compress in a cantilever fashion, which will work satisfactorily, but will not work as efficiently as the embodiment of FIG.  2 . 
     Another embodiment of the present invention is illustrated in FIG.  6 . In this embodiment, the invention comprises the nut  20  and a compression member  40  that comprises the bushing portion  37  of the single piece compression tube member of FIG.  5 . As the nut  20  is tightened, the tapered flange  22  bears against the tapered edge  41  of bushing  40  causing the portions  42  of the bushing  40  between the slots  38  to cantilever inwardly and against the outer circumference of the hopper tube  29 . In operation, the nut  20  is fitted onto the hopper tube  29 , the bushing  40  is then fitted onto the hopper tube  29  and is moved axially until the protruding lip of a snap ring  43  snaps into an annular groove provided in the bushing  40 . The hopper tube is then inserted into the opening  17  in gun  11 . Nut  20  is moved downward, sliding over bushing  40  and is threaded into the correspondingly threaded opening  17  in gun  11 . The interaction of the tapered ends of bushing  40  and nut  20  cause the bushing to bear tightly against the hopper tube  29 , completing the connection. 
     It is to be understood that turning any member end for end, or providing a compressible connection where the tube member attaches to the gun do not fall outside the scope of the present invention comprising attaching a hopper to a paint ball gun using an adaptor in combination with a compressible member. For example, Where the gun includes a tubular member extending out of the gun, another compression fitting located at the bottom of the adaptor tube can be used. In this embodiment, another bushing is fitted within another nut, both of which are positioned in a direction opposite to the bushing and nut at the top of the adaptor tube. 
     In order that the connection between the hopper  12  and the gun  11  can be made and disengaged in the field, and without tools, the outside surfaces of the cylindrical member  14  and the nut  20  can be knurled to permit hand tightening and loosening. 
     While the invention has been described, disclosed, illustrated and shown in certain terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be nor should it be deemed to be limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved.

Technology Category: 2