Patent Publication Number: US-6655065-B1

Title: Barrel catch mechanism

Description:
BACKGROUND 
     1. Field of Invention 
     This invention relates to firearms, specifically to the barrel catch mechanism of a small handgun. 
     2. Description of Prior Art 
     Barrel catch mechanisms for handguns have a long history. Hinged barrel revolvers typically use a catch which locks the topstrap to the frame. This catch usually consists of a rotating member; however, a push button type is also shown in U.S. Pat. No. 368,599 (Marlin). 
     Hinged barrel pistols, which often do not use a topstrap, show a greater variety of barrel catch configurations. Among the barrel catches used in hinged barrel pistols are the rotating cam of the Remington double derringer, the rotating stirrup of the High Standard derringer, the sliding catch of the COP .357, the triggerguard actuated catch of the Thompson/Center Contender, and the push button catch of U.S. Pat. No. 44,123(Stevens). Hinged barrels are comparatively rare in self loading pistols; however, a frame mounted rotating catch is used in the Le Francais self loading pistols, as well as in some current Beretta and Taurus models. 
     Although the prior art is filled with barrel catches for hinged barrel handguns, heretofore known barrel catch mechanisms suffer from a number of disadvantages, particularly when applied to small handguns: 
     (a) Compact barrel catch mechanisms suitable for small handguns provide low strength and thereby limit the gun to the use of low energy cartridges. 
     (b) Robustly designed barrel catch mechanisms offering high strength use comparatively large components, or, are otherwise not readily adaptable to small handguns. 
     (c) Known barrel catches are ergonomically difficult to operate when miniaturized. 
     (d) Known barrel catches may interfere with the comfortable gripping of a small handgun. 
     (e) Barrel catch mechanisms located above the bore axis, or requiring a hinge above the bore axis, needlessly increase overall handgun height. 
     OBJECTS AND ADVANTAGES 
     Accordingly, among the objects and advantages of the present invention are: 
     (a) to provide a barrel catch mechanism suitable for small handguns which offers robustness and the strength to contain high energy cartridges. 
     (b) to provide a barrel catch mechanism which is ergonomically easy to operate. 
     (c) to provide a barrel catch mechanism which does not interfere with the comfortable gripping of a small handgun. 
     (d) to provide a barrel catch mechanism which is not a design constraint to minimizing handgun height. 
    
    
     DRAWING FIGURES 
     FIG. 1 is a left side view of a single shot pistol incorporating the invention. 
     FIG. 2 is a right side view of a single shot pistol incorporating the invention. 
     FIG. 3 is a partial sectional left side view with barrel locked and rotated into loading position. 
     FIG. 4 is a partional sectional left side view with barrel unlocked. 
     FIG. 5 is an isometric view of the locking piece. 
     FIG. 6 is an isometric view of the actuator. 
     FIG. 7 is a bottom view of the barrel. 
     FIG. 8 is a top view of the frame. 
     FIG. 9 is a left side view of the frame. 
     FIG. 10 is a right side view of the frame. 
     FIG. 11 is a partial sectional front view with barrel locked. 
     FIG. 12 is a partial sectional front view with barrel unlocked. 
     FIG. 13 is a partial sectional front view showing an additional embodiment of the locking stud. 
    
    
     REFERENCE NUMERALS IN DRAWING 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 1 
                 Single shot pistol 
               
               
                   
                 2 
                 Left grip plate 
               
               
                   
                 3 
                 Frame 
               
               
                   
                 4 
                 Triggerguard 
               
               
                   
                 5 
                 Barrel 
               
               
                   
                 6 
                 Right grip plate 
               
               
                   
                 7 
                 Hinge pin 
               
               
                   
                 9 
                 Forward lug 
               
               
                   
                 11 
                 Rear lug 
               
               
                   
                 12 
                 Barrel bore 
               
               
                   
                 13 
                 Aperture 
               
               
                   
                 15 
                 Forward well 
               
               
                   
                 17 
                 Rear well 
               
               
                   
                 19 
                 Locking piece 
               
               
                   
                 21 
                 Locking stud 
               
               
                   
                 23 
                 Actuator 
               
               
                   
                 25 
                 Bottom radius of rear lug 
               
               
                   
                 27 
                 Front radius of rear lug 
               
               
                   
                 29 
                 Rear radius of rear lug 
               
               
                   
                 30 
                 Rear radius of forward lug 
               
               
                   
                 31 
                 Front radius of rear well 
               
               
                   
                 32 
                 Rear radius of forward well 
               
               
                   
                 33 
                 Rear radius of rear well 
               
               
                   
                 35 
                 Top radius of catch 
               
               
                   
                 37 
                 Bottom radius of catch 
               
               
                   
                 39 
                 Threaded through hole 
               
               
                   
                 41 
                 Threaded 
               
               
                   
                 43 
                 end of actuator 
               
               
                   
                 45 
                 Push button 
               
               
                   
                 47 
                 Through hole 
               
               
                   
                 49 
                 Counterbore 
               
               
                   
                 51 
                 Recess 
               
               
                   
                 53 
                 Compression spring 
               
               
                   
                 55 
                 Camming surface 
               
               
                   
                   
               
            
           
         
       
     
     Description—FIGS.  1  to  13   
     FIGS. 1 and 2 show a single shot pistol  1  which incorporates the present invention. Pistol  1  has a frame  3  with an integral triggerguard  4 , a left grip plate  2 , a right grip plate  6 , and a hinged barrel  5 . A comparable pistol is disclosed in U.S. Patent applications titled “Passive Safety Mechanism” and “Firing Mechanism” filed Oct. 31, 1997 which are hereby incorporated by reference in their entirety herein. 
     FIG. 4 shows barrel  5  in the loading position. Barrel  5  has a forward lug  9 . Barrel  5  is connected to frame  3  by a hinge pin  7  which passes through forward lug  9  and triggerguard  4 . Barrel  5  also has a rear lug  11 . Rear lug  11  is an underlug with a transverse aperture  13 . Triggerguard  4  has a forward well  15  which accepts forward lug  9  of barrel  5 . Frame  3  also has a rear well  17  which is transversely accessible to a locking piece  19 . Locking piece  19  has a cantilever locking stud  21  and is controlled by a spring loaded actuator  23 . 
     FIG. 3 shows that rear lug  11  is accepted by rear well  17 . Rear lug  11  incorporates a bottom radius  25  in order to avoid interference with rear well  17  during rotation of barrel  5 . With barrel  5  rotated into the battery position as shown, locking stud  21  of locking piece  19  engages rear lug  11  through aperture  13 . 
     FIG. 7 shows that front lug  9  has a rear radius  30 . FIG. 7 also shows that rear lug  11  incorporates both a front radius  27  and a rear radius  29 . Rear well  17  has a corresponding shape. FIG. 8 shows that rear well  17  has a front radius  31  and a rear radius  33 . In addition forward well  15  has a rear radius  32 . The radiused shape of rear well  17  allows the well to be cut with a standard end mill and reduces potential stress concentrations. 
     FIG. 5 depicts locking piece  19 . Locking piece  19  has both a top radius  35  and a bottom radius  37 . Locking stud  21  is cylindrical and tangent to top radius  35 . A threaded through hole  39  is provided to accept actuator  23 . 
     FIG. 6 shows actuator  23 . Actuator  23  is a cylindrical member having a threaded end  41 . Opposite threaded end  41  is a larger diameter head  43  having a fully radiused end which serves as a push button  45 . 
     FIG. 9 depicts a through hole  47  and a counterbore  49  in the left side of frame  3 . Hole  47  and counterbore  49  accept actuator  23 . Moving on to FIG. 10, hole  47  is aligned with a recess  51  designed to accept locking piece  19 . Recess  51  is deep enough to provide access to well  17 . This geometry is shown as hidden lines in FIG.  8 . 
     FIG. 11 shows barrel  5  in the locked position. Locking stud  21  engages rear lug  11 . Rear lug  11  is centered beneath a barrel bore  12 . Locking piece  19  is maintained in the locked position by the force of a helical compression spring  53  which bears upon head  43 . Compression spring  53  is located in counterbore  49  and is concentric with actuator  23 . Push button  45  is accessible through a relieved portion of right grip plate  2 . 
     FIG. 12 shows barrel  5  in the unlocked position. Adequate force applied to push button  45  transversely translates locking piece  19  such that locking stud  21  is disengaged from rear lug  11 . Barrel  5  may now be freely rotated upward for loading. The displacement of locking piece  19  is limited in magnitude such that locking piece  19  does not extend beyond frame  3 . This allows locking piece  19  and corresponding recess  51  to be concealed under right grip plate  6 . 
     FIG. 13 shows an alternate embodiment. A camming surface  55  has been applied to locking stud  21  to provide for automatic closing of the barrel. 
     Conclusion, Ramifications, and Scope 
     Thus, the reader will see that the barrel catch mechanism of this invention is compact and suitable for small handguns, while also providing the robustness and strength required to contain high energy cartridges. In addition, the catch is ergonomically easy to operate, does not interfere with comfortably gripping a small handgun, and is not a design constraint to minimizing handgun height. 
     Although the description above contains many specificities, these should not be construed as limiting the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible. For example, the locking stud can have other cross sectional shapes, such as rectangular, oval, trapedzoidal, etc.; the locking piece can be changed in shape and orientation; the transverse locking force can be provided by a different type of spring; the locking surface of the rear lug can be changed in shape, a portion of the actuator can be made integral with the locking piece, etc. 
     Accordingly, the scope of the invention should be determined not by the embodiment(s) illustrated, but, by the appended claims and their legal equivalents.