Patent Publication Number: US-11644257-B1

Title: Auto-locking magazine extension

Description:
RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Patent Application No. 63/299,731, filed on Jan. 14, 2022 and entitled “AUTO-LOCKING MAGAZINE EXTENSION,” the entire contents of which are expressly incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Magazine extenders for increasing the capacity of firearm magazines are known. Such extenders typically operate by coupling to a lower open end of a magazine to increase the length and volume thereof and provide more room for additional rounds. 
     Since firearms are subject to substantial forces during operation, such as those caused by recoil or by dropping the firearm or magazine on a hard surface, it is desirable that a magazine extender be affixed to a magazine in a substantially robust and secure manner that prevents dislodgment. It is also desirable that the locking mechanism and associated components of the extender do not interfere with the internal workings of the magazine, such as the magazine spring and follower. Since dirt and debris accumulated during operation of a firearm can hinder reliability of magazines and extenders, users also strongly prefer extenders that can be affixed to or removed from a magazine in the field in a toolless (or near toolless) fashion. 
     BRIEF SUMMARY OF THE INVENTION 
     Various embodiments of the subject disclosure provide durable auto-locking magazine extenders, magazines with auto-locking magazine extenders, and firearm assemblies with magazines having auto-locking magazine extenders. At least some embodiments of the auto-locking magazine extender also resist inadvertent disassembly or damage during operation of a firearm and are capable of being installed/uninstalled in a toolless (or near toolless) fashion. 
     In accordance with an exemplary embodiment of the subject disclosure, a magazine extender is provided. The extender includes a baseplate structured to receive a lower open end of a magazine; a side bracket structured to couple to the baseplate for securing the magazine; and a locking pin selectively moveable into a locked position to lock the side bracket to the baseplate and an unlocked position to unlock the side bracket from the baseplate, in which the locking pin is prevented from being moved to the unlocked position by a handgrip of a firearm when the magazine is inserted into the handgrip. 
     In accordance with an aspect of the subject disclosure, the baseplate includes a securing slot sized to receive a rail of the magazine. 
     In accordance with another aspect of the subject disclosure, the baseplate includes a floor having an upper surface positioned to engage a magazine spring of the magazine 
     In accordance with still another aspect of the subject disclosure the baseplate includes a guide channel and the side bracket includes a leg engaging with the guide channel when the side bracket is coupled to the baseplate. 
     In accordance with yet another aspect of the subject disclosure the baseplate includes a floor having a window, the side bracket includes a through-bore aligned with the window when the side bracket is secured to the baseplate, and the locking pin includes a shaft positioned within the through-bore and a key structured to engage with the window of the baseplate when the locking pin is moved to the locked position. 
     In accordance with still another aspect of the subject disclosure, the key of the locking pin is shaped to engage the window of the baseplate only when the locking pin is in a single rotational orientation. 
     In accordance with yet another aspect of the subject disclosure, the key and window are each trapezoid-shaped. 
     In accordance with still another aspect of the subject disclosure, the side bracket includes a receptacle in communication with the through-bore and the locking pin has a stop positioned within the receptacle. 
     In accordance with yet another aspect of the subject disclosure, the receptacle has an upper face and the floor of the baseplate has an upper surface, the upper face and the upper surface limiting movement of the stop within the receptacle. 
     In accordance with still another aspect of the subject disclosure, the side bracket includes an upper surface and a portion of the shaft of the locking pin protrudes above the upper surface when the locking pin is moved to the unlocked position. 
     In accordance with yet another aspect of the subject disclosure, the portion of the shaft does not protrude above the upper surface of the side bracket when the locking pin is moved to the locked position. 
     In accordance with still another aspect of the subject disclosure, the handgrip of the firearm prevents the portion of the locking pin from protruding fully above the upper surface of the side bracket when the magazine is inserted into the handgrip of the firearm, thereby preventing the locking pin from being moved to the unlocked position. 
     In accordance with another exemplary embodiment of the subject disclosure, an extended magazine is provided. The extended magazine includes a magazine having a lower open end; a baseplate structured to receive the lower open end of the magazine; a side bracket structured to couple to the baseplate for securing the magazine; and a locking pin selectively moveable into a locked position to lock the side bracket to the baseplate and an unlocked position to unlock the side bracket from the baseplate, in which the locking pin is prevented from being moved to the unlocked position by a handgrip of a firearm when the magazine is inserted into the handgrip. 
     In accordance with still another exemplary embodiment of the subject disclosure, a firearm assembly is provided. The firearm assembly includes a firearm having a handgrip; a magazine in the handgrip and having a lower open end; a baseplate structured to receive the lower open end of the magazine; a side bracket structured to couple to the baseplate for securing the magazine; and a locking pin selectively moveable into a locked position to lock the side bracket to the baseplate and an unlocked position to unlock the side bracket from the baseplate, in which the locking pin is prevented from being moved to the unlocked position by the handgrip of the firearm. 
     In accordance with yet another exemplary embodiment of the subject disclosure, a magazine extender is provided for coupling to an open end of a magazine. The magazine extender includes a baseplate including an open proximal end, a closed distal end, a floor having a window and extending between the proximal and distal ends, and two side walls at opposite lateral sides of the floor, each of the side walls including a guide channel and a securing slot for receiving a rail of the magazine; a side bracket including an upper surface, a lower surface, a receptacle extending upwardly from the lower surface, and a through-bore extending upwardly from the receptacle and terminating at the upper surface of the main body, and two legs extending distally, each leg sized to closely engage a respective one of the guide channels of the baseplate when the side bracket is secured to the baseplate; and a locking pin including a stop positioned within the receptacle of the side bracket, a shaft extending upwardly from the stop and into the through-bore of the side bracket, and a key extending downwardly from the stop, in which the locking pin is selectively movable into a locked position and an unlocked position, the key of the locking pin engaging with the window of the baseplate in the locked position to lock the side bracket to the baseplate, the key of the locking pin disengaged from the window of the baseplate in the unlocked position to unlock the side bracket from the baseplate, and in which a portion of the shaft of the locking pin protrudes above the upper surface of the side bracket when the locking pin is moved into the unlocked position. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The following detailed description of an exemplary embodiment of the subject disclosure will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, there is shown in the drawings an exemplary embodiment. It should be understood, however, that the subject application is not limited to the precise arrangements and instrumentalities shown. 
         FIG.  1    is a side view of a firearm assembly including a firearm with a magazine and an auto-locking magazine extender in accordance with an exemplary embodiment of the subject disclosure; 
         FIG.  2    is an exploded perspective view of the firearm assembly of  FIG.  1   ; 
         FIG.  3    is a side sectional view of the magazine and magazine extender of  FIG.  1   ; 
         FIG.  4    is a front sectional view of the magazine and magazine extender of  FIG.  1   ; 
         FIG.  5    is an exploded perspective view of the magazine and magazine extender of  FIG.  1   ; 
         FIG.  6    is an exploded perspective view of the magazine extender of  FIG.  1   ; 
         FIG.  7    is another exploded perspective view of the magazine extender of  FIG.  1   ; 
         FIG.  8    is still another exploded perspective view of the magazine extender of  FIG.  1   ; 
         FIG.  9    is a perspective sectional view of the firearm assembly of  FIG.  1    showing a locking pin in a lower locked position; 
         FIG.  10    is a perspective sectional view of the firearm assembly of  FIG.  1    showing the locking pin in an upper unlocked position and the magazine removed partially from the firearm; 
         FIG.  11    is a diagram detailing a process for assembling the magazine extender of  FIG.  1    on a magazine of a handgun; and 
         FIG.  12    is a diagram detailing a process for disassembling and removing the magazine extender of  FIG.  1    from a magazine of a handgun. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to an exemplary embodiment of the subject disclosure illustrated in the accompanying drawings. Wherever possible, the same or like reference numbers will be used throughout the drawings to refer to the same or like features. It should be noted that the drawings are in simplified form and are not drawn to precise scale. In reference to the disclosure herein, for purposes of convenience and clarity only, directional terms such as upper, lower, top, bottom, above, below and diagonal, are used with respect to the accompanying drawings. Such directional terms used in conjunction with the following description of the drawings should not be construed to limit the scope of the subject disclosure in any manner not explicitly set forth. Additionally, the term “a,” as used in the specification, means “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import. 
     “About” as used herein when referring to a measurable value such as an amount, a temporal duration, and the like, is meant to encompass variations of ±20%, ±10%, ±5%, ±1%, or ±0.1% from the specified value, as such variations are appropriate. 
     “Substantially” as used herein shall mean considerable in extent, largely but not wholly that which is specified, or an appropriate variation therefrom as is acceptable within the field of art. 
     “Exemplary” as used herein shall mean serving as an example. 
     Throughout the subject application, various aspects thereof can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the subject disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, and 6. This applies regardless of the breadth of the range. 
     Furthermore, the described features, advantages and characteristics of the exemplary embodiments of the subject disclosure may be combined in any suitable manner in one or more exemplary embodiments. One skilled in the relevant art will recognize, in light of the description herein, that the subject disclosure can be practiced without one or more of the specific features or advantages of a particular exemplary embodiment. In other instances, additional features and advantages may be recognized in certain exemplary embodiments that may not be present in all exemplary embodiments of the present disclosure. 
     Referring now to the Figures, there is shown an exemplary auto-locking magazine extender  100  in accordance with the subject disclosure. Magazine extender  100  increases the round capacity of a magazine  500  of handgun  600  or other firearm, such as a rifle or shotgun. As best shown in  FIGS.  1  and  2   , handgun  600  includes a receiver assembly  620  having a hollow handgrip  605  sized to receive magazine  500 , a magazine release button  615  on handgrip  605 , a slide  625  coupled to the upper portion of receiver assembly  620  and a trigger assembly  630  operable to fire rounds stored in magazine  500 . Handgun  600  also includes other well-known components and structures not shown or described herein. 
     As shown in  FIGS.  3 - 10   , magazine extender  100  includes a baseplate  200  for receiving an open end  505  of magazine  500 , a side bracket  300  structured to releasably couple to baseplate  200  for securing magazine  500  thereto and a locking pin  400  for locking side bracket  300  to baseplate  200 . 
     As best shown in  FIGS.  5  through  8   , baseplate  200  includes an open proximal end  205 , a closed and rounded distal end  210 , a beveled floor  215  with an upper surface  217  extending between proximal and distal ends  205 ,  210  and having a trapezoid-shaped window  220  at proximal end  205 , and two side walls  225  at opposite lateral sides of floor  215  and extending between proximal and distal ends  205 ,  210 . The inner face of each wall  225  includes a lower lateral protrusion  230  and a guide  235  which together form a guide channel  240  extending between proximal and distal ends  205 ,  210 . Each guide  235  also cooperates at its top end with a lateral and inwardly projecting lip  245  to form a securing slot  250  sized to receive rails  510  of magazine  500 . Baseplate  200  and its features are formed integrally into one monolithic piece (such as by injection molding), though it should be appreciated that baseplate  105  may be formed from multiple separate pieces and be constructed from any material(s) suitable for its intended purpose. 
     Side bracket  300  includes a main body  305  and two legs  310  extending distally from opposite sides of main body  305 , each of which is sized and positioned to closely engage a respective guide channel  240  of baseplate  200 . Main body  305  includes a curved proximal face  312 , two lateral and distally facing receipt channels  315 , a lower surface  320 , a receptacle  325  extending upwardly from lower surface  320  and having an upper face  330 , and a cylindrical through-bore  335  communicating with receptacle  325  and extending upwardly therefrom and terminating at an upper surface  340 . Like baseplate  200 , side bracket  300  and its features are formed integrally into one monolithic piece, though it should be appreciated that side bracket  300  may be formed from multiple separate pieces and be constructed from any suitable material(s). 
     Locking pin  400  includes a stop  405 , a cylindrical shaft  410  extending upwardly from stop  405  and terminating at an upper face  415 , and a trapezoid-shaped key  420  extending downwardly from stop  405  and having respective proximal and distal faces  425 ,  430 . 
     To ensure proper alignment of side bracket  300  with respect to baseplate  200 , guide channels  240  of baseplate  200  closely receive legs  310  of side bracket  300  and receipt channels  315  of side bracket  300  closely receive the proximal ends of guides  235 . This ensures that lower surface  320  of side bracket  300  closely engages upper surface  217  of floor  215  of baseplate  200  and aligns receptacle  325  of side bracket  300  with window  220  of baseplate  200 . Shaft  410  of locking pin  400  extends upwardly through bore  335  of side bracket  300 , with stop  405  being positioned within receptacle  325 . When extender  100  is secured to magazine  500 , upper face  330  of receptacle  325  and upper surface  217  of floor  215  limit movement of stop  405  within receptacle  325  between a lower locked position, in which proximal face  425  of key  420  engages proximal side  222  of window  220  to prevent removal of side bracket  300  laterally from baseplate  200  (see  FIG.  9   ), and an upper unlocked position, in which key  420  clears window  220  to allow removal of side bracket  300  laterally from baseplate  200  (see  FIG.  10   ). By ensuring that locking pin  400  locks side bracket  300  in a lower position (rather than an upper or other position), magazine extender  100  provides enhanced robustness against inadvertent unlocking and disassembly caused by a falling magazine  500  striking a hard surface (such as when magazine release button  615  is pressed in typical fashion to allow empty magazine  500  to fall out of handgun  600  under force of gravity). In such an event, magazine  500  falls straight and typically strikes the ground in an upright position (extender  100  first), upon which inertia urges locking pin  400  even more strongly into the lower locked position. Likewise, recoil forces (which typical jolt a firearm upwards) may more strongly seat locking pin  400  in the lower locked position. 
     Key  420  of locking pin  400  is trapezoid-shaped and sized to engage trapezoid-shaped window  220  in the assembled state only when locking pin  400  is in a specific rotational orientation. This ensures that upper face  415  of pin  400  (which is cut at an angle with respect to the axis of shaft  410 ) lies flush with upper surface  340  of side bracket  300  when pin  400  is in the lower locked position. While key  420  and window  220  are trapezoid-shaped, it should be appreciated that these features may be designed with different shapes or keying features to ensure proper rotational alignment of pin  400  or, alternatively, these features need not be keyed at all, such as with respect to embodiments that do not require a specific rotational orientation of pin  400 . Further, although shaft  410  and through-bore  335  are generally cylindrical with cross-sections that are substantially circular in shape, it should be appreciated that these features may be designed to have different cross-sections, such as, e.g., square or triangle shaped cross-sections, and that various embodiments of the subject disclosure are not intended to be limited to any particular cross-sectional shape of shaft  410  or through-bore  335 . 
     As best shown in  FIGS.  9 - 10   , when magazine  500  with magazine extender  100  is inserted and secured within handgrip  605  of handgun  600 , a lower surface  610  of handgrip  605  automatically locks side bracket  300  to baseplate  200  by engaging with upper face  415  of locking pin  400  to ensure pin  400  cannot be moved into the upper unlocked position during operation of handgun  600  (see  FIG.  9   ). However, to the extent locking pin  400  is inserted into side bracket  300  in the wrong rotational orientation, or side bracket  300  is not fully inserted into baseplate  200  to align key  420  with window  220 , key  420  of pin  400  will not engage window  220 , thereby maintaining locking pin  400  rigidly in the upper unlocked position. In this position, upper face  415  of shaft  410  engages and stops handgrip  605  at some distance above upper surface  340  of side bracket  300  to prevent magazine  500  from being fully inserted and secured within handgrip  605 . This provides a safety feature that prohibits installation of magazine  500  into handgun  600  when magazine extender  100  is not properly assembled and secured to magazine  500 . In the event locking pin  400  and/or side bracket  300  are damaged and become dislodged from baseplate  200 , handgun  600  still may be safely operated at least temporarily, as biasing forces exerted against floor  215  by magazine spring  515  produce frictional forces that maintain rails  510  of magazine  500  within securing slots  250  of baseplate  200 . 
     Referring now to  FIG.  11   , there is shown a diagram detailing a process  1100  for assembling magazine extender  100  on magazine  500  of handgun  600 . The process begins at step  1105  and proceeds to step  1110 , at which a user compresses magazine spring  515  of magazine  500 , slides rails  510  of magazine  500  distally into securing slots  250  of baseplate  200 , and releases spring  515  to permit engagement of spring  515  with floor  215  of baseplate  200 . The process then proceeds to step  1115 . At this step, the user inserts shaft  410  of locking pin  400  upwardly into through-bore  335  of side bracket  300  until key  420  is fully maintained within receptacle  325 . Then, at step  1120 , the user inserts legs  310  of side bracket  300  laterally into guide channels  240  of baseplate  200  until key  420  of pin  400  aligns with window  220  of baseplate  200 . The process then proceeds to step  1125 , at which the user presses upper face  415  of shaft  410  downwardly to urge locking pin  400  into the lower locked position, thereby locking side bracket  300  to baseplate  200 . Alternatively, locking pin  400  may be secured into the locked position by inserting and securing magazine  500  within handgrip  605  of handgun  600 . Insertion of magazine  500  in this manner causes lower surface  610  of handgrip  605  to engage with upper face  415  of shaft  410  to urge locking pin  400  downwardly into the locked position. In other embodiments, locking pin  400  simply falls downwardly into the locked position under force of gravity when key  420  of locking pin  400  aligns with window  220  of baseplate  200 . In still other embodiments, a biasing member (such as a compression spring) is positioned within receptacle  325  between stop  405  of pin  400  and upper face  330  of receptacle  325  to provide a biasing force to urge pin  400  into the lower locked position when key  420  and window  220  align. The process then ends at step  1130 . 
     Referring now to  FIG.  12   , there is shown a diagram detailing a process  1200  of removing magazine extender  100  from magazine  500  of handgun  600 . The process begins at step  1205  and proceeds to step  1210 , at which a user removes magazine  500  from handgun  600  by depressing the magazine release button  615  of firearm  600  and sliding magazine  500  downwardly out of handgrip  605 . The process then proceeds to step  1215 . At this step, the user inserts a fingernail, pin punch, ball point pen or other readily available tool or structure into window  220  to urge locking pin  400  upwardly into the upper unlocked position, thereby disengaging key  420  from window  220  of baseplate  200 . Then, at step  1220 , the user removes side bracket  300  by sliding it proximally with respect to baseplate  200 . With side bracket  300  removed, the process proceeds to step  1225 , at which the user compresses magazine spring  515  slightly and removes magazine  500  from baseplate  200  by sliding it proximally until rails  510  fully clear securing slots  250  of baseplate  200 . The process then ends at step  1230 . 
     It should be appreciated by those skilled in the art that changes may be made to the exemplary embodiments described above without departing from the broad inventive concept thereof. It is to be understood, therefore, that this disclosure is not limited to the particular exemplary embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the claims defined herein.