Patent Publication Number: US-11662166-B2

Title: Reinforced magazine feed lips with rear actuated last round bolt hold open and follower

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims the priority of U.S. Ser. No. 63/186,842 filed May 11, 2021. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to a magazine, such as affixed within a magazine well of an AR type firearm. More particularly, the present invention discloses the provision of a plastic injection molded magazine having a redesign upper end including reinforced feed lips, such as incorporated into a bridge or tower integrated into the magazine construction. An area of the magazine top surrounding the feed lips is substantially closed with the exception of an upward follower projection which, upon discharging of a final round, elevates a separate bolt catch or custom drop in bolt hold adaptor into contact with the forwardly displacing bolt. Other features include forming the feed ramp integrally with specific versions of the magazine tube in order to simplify construction and reduce cost of manufacture. 
     BACKGROUND OF THE INVENTION 
     Attachable magazines are known in the relevant art, such as for use with AR type firearms. Conventional magazine construction includes each of a magazine body with a bottom attachable floor plate supporting an interior and upwardly biasing coil spring, along with a follower supported upon an upper end of the spring. Depending upon the capacity of the magazine, a plurality of cartridges are progressively loaded through feed lips configured into an upper end of magazine, downwardly compressing the interior supported and upwardly biased follower toward the floor plate. Upon inserting the magazine and progressively firing rounds from the firearm, the follower progressively displaces upwardly according to its spring bias until, following discharge of a last round, the follower is fully upwardly actuated in order to come into contact with and to arrest the forward traveling motion of the bolt in order to maintain the chamber in an open position. 
     Such traditional magazines are often constructed of stamped steel. More recently, injection molded plastics have been utilized in the construction of the magazines, with experienced shortcomings including instances of outward swelling of the feed lips, such as in response to prolonged periods of the inner spring exerting a constructed upward bias against the cartridges held against the feed lips of such polymer magazines. Also, known magazine designs include a substantially open top area toward the back end in order to allow room for the ascending follower to contact the vehicle bolt catch after the last round has been fired, this often further compromising the structural integrity of the magazine. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a magazine for use with an AR type firearm having a lower receiver with a magazine well in communication with an attached upper receiver incorporating a reciprocating bolt. The magazine includes an elongated body installable into the magazine well and having a top, interconnected front, sides and rear walls, with a closed bottom to collectively define a cartridge holding interior. 
     A spring is supported within the interior in contact with the closed bottom which either defines a bottom of the magazine or a separate floor plate secured to an open lower perimeter of the magazine body to define the closed bottom. The follower is positioned atop the spring in an upwardly biased direction toward a main opening in the top, through which the cartridges are loaded into the magazine. 
     A feed tower or other structurally supporting structure is integrated into the top and supports a pair of connected and reinforced feed lips positioned along opposed edges defining the main opening for facilitating the loading of the cartridges. The magazine top has a separate aperture positioned rearward of the feed tower, with a rear extending and upward projection of the follower aligning with the aperture such that, following discharge of a final cartridge from the firearm, the rear projection elevates through the rear aperture and above the top to actuate a bolt catch or separate drop in bolt hold open component incorporated into the firearm (this can include being incorporated into a single receiver firearm or alternatively an upper attachable receiver which secures to a lower receiver in turn having the magazine well), and in order to arrest the forward return motion of the reciprocating bolt following discharge of the last cartridge. 
     The feed tower is located toward closer to the rear of the magazine body than the front. In certain variants, a feed ramp is integrated into the top of the magazine, proximate the front. The upper receiver further can include either of a custom bolt catch or a bolt hold open adapter which is upwardly engaged by the elevating rear magazine projection in order to arrest a return forward cycling motion of the reciprocating bolt. Alternatively, and in absence of the separate bolt catch or hold open adaptor, at least one variant provides a main contoured upper surface of the follower which, upon discharge of the final cartridge, elevates above the feed lips in order to arrest the return forward cycling motion of the reciprocating bolt. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which: 
         FIG.  1    is a perspective view of a magazine and follower according to a first variant of the present invention including upper end located and reinforced feed lips in combination with a magazine tube integrated feed ramp and rear top aperture for seating the upwardly projecting rear portion of the follower; 
         FIG.  2    is a perspective view of another variant of the magazine and follower depicted in  FIG.  1    for use with a smaller caliber of ammunition; 
         FIG.  3    is a perspective view of a yet further variant of the magazine and follower depicted in  FIG.  1    for use with a larger caliber of ammunition; 
         FIG.  4    is an enlarged top end perspective of the version of the magazine and follower depicted in  FIG.  2    and better illustrating the bridging reinforcement between the upper feed lips, along with the aperture formed in the closed outer perimeter of the magazine top end surrounding the bridge supported feed lips; 
         FIG.  5    is an upper perspective of a magazine and follower according to a related variant and including a bridging construction between the feed lips to prevent flexing under a full magazine load; 
         FIG.  5 A  is an illustration similar to  FIG.  5    of a further related variant of upper magazine feed lips and bridging structure; 
         FIG.  5 B  is a partial upper perspective of the upper magazine shown in  FIG.  2   ; 
         FIG.  6    is a top perspective of the variant of  FIG.  1   ; 
         FIG.  6 A  is a top perspective of the variant of  FIG.  3   ; 
         FIG.  6 B  is a partial top perspective of the variant of  FIG.  2   ; 
         FIGS.  7 - 7 A  illustrate first and second cutaway environmental views depicting first and second alternate engagement configurations for the magazine follower interacting with the bolt catch or bolt in order to establish a last shot bolt hold open condition; 
         FIGS.  8 - 8 A  depict a pair of upper perspective views of the magazines of  FIGS.  1  and  3    and better showing the upper feed ramp integrated into the body of the magazine; 
         FIG.  9    is a perspective view of the follower of  FIG.  2   , removed from the magazine; 
         FIG.  10    is a cutaway view taken along line  10 - 10  of  FIG.  2    and depicting a seating profile established between the magazine interior and the biasingly supported follower; 
         FIG.  11    is a perspective view of the follower of  FIG.  3   , removed from the magazine; 
         FIG.  12    is a cutaway view taken along line  12 - 12  of  FIG.  3    and depicting a seating profile established between the magazine interior and the biasingly supported follower; 
         FIG.  13    is a perspective view of the follower of  FIG.  1   , removed from the magazine; and 
         FIG.  14    is a cutaway view taken along line  14 - 14  of  FIG.  1    and depicting a seating profile established between the magazine interior and the biasingly supported follower. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the attached illustrations, the present invention discloses a number of related variants (see with further reference to magazine  10  of  FIG.  1   , magazine  100  of  FIG.  2   , and magazine  200  of  FIG.  3   ) of a magazine having a redesign upper end including opposing edge extending (also termed bridge supported) reinforced feed lips extending along both sides of a main opening defined in the magazine for loading the cartridges. As will be further described, an area of the magazine top surrounding the feed lips is substantially closed with the exception of a separate aperture located rearward of the main opening in alignment with an upward follower projection which, upon discharging of a final round, elevates a separate bolt catch or custom drop in bolt hold adaptor into contact with the forwardly displacing bolt. Other features include forming the feed ramp integrally with the magazine tube in order to simplify construction and reduce cost of manufacture. 
       FIG.  1    is a perspective view, generally at  10 , of a magazine and follower according to a first variant of the present invention and including upper end located and reinforced feed lips in combination with a magazine tube integrated feed ramp and rear top aperture for seating the upwardly projecting rear portion of the follower.  FIG.  2    is a perspective view of another variant, generally at  100 , of the magazine and follower depicted in  FIG.  1    for use with a smaller caliber (such as including but not limited to .22 LR) of ammunition and which provides a dual purpose follower for engaging the forward cycling bolt following discharge of a final cartridge. Finally,  FIG.  3    provides a perspective view of a yet further variant  200  of the magazine and follower similar to that depicted in  FIG.  1    for use with a larger caliber of ammunition. 
     In each instance, and as best shown in the cutaway environmental views of  FIGS.  7 - 7 A , the magazine attaches within a magazine well of an AR type lower receiver  2 . An upper receiver is attached to the lower receiver in communication with the magazine well, with the outer housing of the upper not shown in order to reference a bolt carrier group  4  which reciprocates in fore and aft directions in overhead communication with the magazine well and, in a forward most position, for chambering a cartridge from the magazine in order to seat against a chamber location  6  communicating with a forward extending barrel  8 . With reference again to  FIGS.  7 - 7 A , a bolt catch  3  can be associated with a separate drop in component such as a last shot bolt hold open device, this also including other types of bolt hold open adaptors. 
     In each of the variants  10 ,  100  and  200 , the magazine includes an elongated body installable into the magazine well and (with reference to magazine  10  in  FIG.  1   ) having a top  12 , interconnected front  14 , sides  16  and  18  and rear  20  walls, and a bottom  22 . A spring (not shown) is supported within the interior in contact with a floor retention plate (also not shown) which is incorporated into or otherwise separately attached to close the bottom. 
     Referring again to  FIG.  1    a follower  24  is supported in positioned atop the interior spring so as to be biased in an upward direction toward an opening in the top, through which the cartridges are loaded into the magazine. 
     A variant of a reinforcing superstructure, also termed a feed tower, is integrated into the top of each magazine configuration and supports a pair of feed lips positioned along opposed edges defining an opening for facilitating the loading of the cartridges. Each of the magazine configurations  10 ,  100  and  200  exhibits a different configuration of feed tower, with magazine  10  showing a tower  26  with upper configured feed lips  28  and  30  which are further connected at  19  as shown in  FIG.  1    as well as to interconnected the separate rear aperture  32  for seating the rear upward projection  34 . As described herein, the feed lips are defined as an integral part of the body, such as which can be constructed from an injection molded plastic. The construction of the feed lips  28 / 30  with reinforced connection  19  are reinforced to limit outward swelling in response to the upward forces exerted by the spring against the inserted cartridges. 
     As further shown in  FIG.  1   , the aperture  32  formed in the top  12  (see also  FIGS.  6 - 6 B ) is positioned rearward of the feed tower, with the rear upward projection  34  of the follower aligning with the aperture such that, following discharge of a final cartridge from the upper receiver, the rear projection  34  elevates above the top  12  of the magazine in order to arrest the forward returning motion of the bolt. This is best depicted in  FIGS.  7 - 7 A  which illustrate first and second cutaway environmental views depicting first and second alternate engagement configurations for the magazine follower (this at  124  for the variant of  FIG.  2   ) interacting with the bolt catch or bolt in order to establish a last shot bolt hold open condition. The follower  124  includes a rear attached and upwardly extending projection  126  which aligns with a separate rear slot or aperture  128  (from the main opening defined between the feed lips  104 / 106  in the rear of the magazine top  120  as again shown in  FIG.  2   ). The magazine of  FIG.  2    also depicts a rear reinforced connection  103  established between the feed lips  104 / 106  as shown, again for separating the rear aperture  128  as well as for preventing outward swelling of the feed lips in response to upward forces exerted upon the inserted cartridges by the spring. 
     Also depicted in  FIG.  1    is a forward located feed ramp  36  integrated into the top  12  of the magazine assisting in feeding of cartridges into the upper receiver chamber. A similar feed ramp  236  is configured into the forward top location of the corresponding magazine design  200 , with the smaller caliber magazine  100  (such as utilized with a smaller caliber cartridge including a .22 LR) not including a similarly configured feed ramp. 
     The smaller caliber magazine  100  in  FIG.  2    is again shown and corresponds to most of the features of the corresponding magazine  10  of  FIG.  1   , except as to a redesign of the feed tower which depicts a curved end profile at  102  separating the feed lips  104 / 106  and defining the reinforced connection  103  and extending upwardly from a top  120  of the magazine and through which projects the inner spring supported follower  124  in the uppermost position. An upper contoured edge the main follower body, again at  124 , can be ascending at a forward end, this in order to provide the dual function (otherwise provided by the rear attached and upwardly extending projection  126  seating through separate aperture  128 ) of restraining the return motion of the bolt and in order to establish a last shot bolt hold open condition. 
     A reconfiguration of the feed lips (see at  104  and  106 ) is provided at the top of the feed tower, through which the cartridges (not shown) successively fed or loaded into the magazine. The feed lips  104  and  106  again are reinforced (see again at  103 ) and prevented from flexing owing to their construction incorporated into the superstructure or feed tower. 
     The magazine design of  FIG.  3    is substantially similar to  FIG.  1    except as to scale or cartridge size, with similar features depicted including the arrangement of a feed tower  202  with opposing upper edge arranged and reinforced feed lips  204 / 206  (see also reinforced connection  205  established between the feed lips opposing the main opening and the separate rear aperture  232 ), between which projects a main portion of the follower (at  224 ). The follower also again includes a rear attached and upward projecting portion referenced at  234  which, similar to that depicted at  34  in  FIG.  1   , actuates upwardly through the separate aperture  232  defined rearwardly of the main opening (as defined by the feed lips connecting/reinforcing portion  205  of the magazine tower) for seating the main body portion  224  of the follower in response to a final discharged cartridge, and so that the rear portion  234  in turn upwardly displace a bolt catch or other customized drop in component in order to arrest a forward return cycling of the reciprocating bolt to maintain the chamber in the open position. As with the embodiment of  FIG.  1    (at  36 ), a forward feed ramp  236  is shown in  FIG.  3    which is integrated into the top of the magazine. 
       FIGS.  8 - 8 A  depict a pair of upper perspective views of the magazines of  FIGS.  1  and  3    and better showing the upper feed ramp  236  integrated into the body of the magazine variant  200 . The construction of the magazine top is further such that the feed tower construction (at  202 ) provides reinforcing support to the upper feed lips  204 / 206  in order to prevent deformation or bowing during feeding or retention of the cartridges and owing to the associated spring biasing forces exerted upon the upward biased follower. In this manner, a polymeric magazine construction can provide the necessary structural support for feeding larger caliber ammunition. 
     As again shown in related magazine variant  200  in  FIG.  3   , rear located aperture  232  in the otherwise closed outer perimeter of the magazine top aligns with the upper projecting rear portion  234  of the follower  224 . As previously described, the rear projection  234  upwardly ascends in order to engage any bolt catch or drop in component (such as a last shot bold hold open component) following discharge of a final round. 
       FIG.  4    again provides an enlarged top end perspective of the version of the magazine and follower depicted in  FIG.  2    and better illustrating the bridging reinforcement connecting portion  103  of the tower structure and including the curved end profile  102  between the upper feed lips  104 / 106 . As shown, the connecting portion  103  separates the main cartridge receiving interior from the rear located aperture  128  formed in the closed outer perimeter of the magazine top for seating the rear projecting follower portion  126 . The cartridge rounds are presented forward of the rear position to allow space for the bridge constructed along the back of the feed lips  104 / 106 . The variant provides a dual-purpose follower in which the main portion  124  provides for forward arresting engagement of the cycling bolt, this as a back up to the rear magazine projection  126  for engaging a bolt catch or other suitable drop in component. 
     As further shown in  FIG.  4   , the curved end profile  102  in combination with the reinforced connection  103  stiffens the feed lips  104 / 106  to reduce swelling issues commonly seen in polymer magazines. In typical AR15 magazines, the back of the magazine may be slotted to allow room for the follower to contact the bolt catch after the last round has been fired. Such prior constructions have been found to cause structural instability in the magazine design and to increase the incidence of deformation of the magazine upper and feed lips in order to properly retain and feed the rounds. 
       FIG.  5    is an upper perspective of a magazine and follower according to a related variant, generally at  300 , and including a bridging construction  302  between the feed lips, at  304  and  306 , to prevent flexing under a full magazine load. A rear integral projection  308  of the follower ascends upwardly through an aligning aperture  310  in the otherwise closed outer perimeter of the magazine top, such that additional reinforcing support is imparted to the magazine construction to prevent deformation or bowing in response to the spring loaded upward forces exerted upon and in turn by the magazine follower. 
       FIG.  5 A  is an illustration similar to  FIG.  5    of a further related variant  300 ′ of upper magazine feed lips  304 ′/ 306 ′ and bridging structure  302 ′. A rear integral follower projection is again shown, at  308 ′, and ascends upwardly through an aligning aperture  310 ′ in the otherwise closed outer perimeter of the magazine top, such that additional reinforcing support is again imparted to the magazine construction to prevent deformation or flex/bowing in use. 
       FIG.  5 B  is a partial upper perspective of the upper magazine shown in  FIG.  2    and as substantially shown in  FIG.  4    and better illustrating the configuration of the upward rear follower projection  126  ascending through the rear aperture  128 . As previously described, the follower  124  is dual purpose in that either the main body of the follower or the rear projection  126  can engage the forward return cycling bolt (in the instance of the main body engaging the bolt directly and in the further instance of the rear projection  126  via a bolt catch or other customized drop in component). 
     Proceeding to  FIG.  9   , a perspective view is shown of the follower  124  of  FIG.  2   , removed from the magazine  100 . This magazine and follower combination typically references a smaller caliber cartridge, such as a .22 lr. The follower  124 , includes an inwardly tapered and narrowed main body terminating in an upper planar surface including an upwardly sloping portion  125  and interconnected apex surface  127 . As previously described, this profile provides the .22 lr follower with the dual function of either the main body  124  of the follower or the rear projection  126  engaging the forward return cycling bolt (in the instance of the main body engaging the bolt directly as well as in the further instance of the rear projection  126  via a bolt catch or other customized drop in component). The .22 lr follower  124  further includes a forward end located and downwardly flared configuration (see wings  127  and  129 ). A base portion  131  of the follower  124  includes a reverse flared configuration with side tabs (one of which is shown at  133 ) for seating an upper edge of the magazine spring (not shown). 
       FIG.  10    is a cutaway view taken along line  10 - 10  of  FIG.  2    and depicting a seating profile established between the magazine interior  100  and the biasingly supported follower. The forward end winged profiles  127 / 129  of the follower body seat within an otherwise open interior of the magazine interior and which, upon discharge of a final cartridge, provide adequate elevating guidance to the follower in the manner depicted in  FIG.  2   . 
       FIG.  11    is a perspective view of the follower of  FIG.  3   , removed from the magazine, and which can include for use with such as a 5.7×28 mm sized cartridge. As previously described, the follower includes a trapezoidal shaped and flattened upper profile. A pair of downward extending legs  225  and  227  define inner arcuate profiles which seat the magazine spring therebetween within the magazine interior. 
     Also depicted are side notches  229  and a small raised pad  231  on the front one of the legs  225  which, when seated within the cutaway of the magazine interior as shown in  FIG.  12   , provides a guided seating profile established between the magazine interior and the biasingly supported follower. As further shown in  FIG.  12   , the cutaway profile of the magazine  200  seats the follower  224  in manner preventing any misalignments during operation and includes each of a main outline  233  for seating the main follower body  224 , a rearward narrowed portion  235  for seating rearward projection  234 , a pair of side locating features  237 / 239  for seating the follower side notches  229  and a forward notch  241  for seating the smaller forward projection  231 . 
       FIG.  13    is a perspective view of the follower  24  of  FIG.  1   , also removed from the magazine, and similar to the variant in  FIG.  11   , also includes a trapezoidal shaped and flattened upper profile, a pair of downward extending legs  25  and  27  define inner arcuate profiles which seat the magazine spring therebetween within the magazine interior, side notches  29  and a small raised pad  31  on the front one of the legs  25  which, when seated within the cutaway of the magazine interior as shown in  FIG.  12   , and provides a guided seating profile established between the magazine interior and the biasingly supported follower. 
     Finally,  FIG.  14    is a cutaway view taken along line  14 - 14  of  FIG.  1    and depicting a similar seating profile established between the magazine interior and the biasingly supported follower of  FIG.  13   . This again includes a main outline  33  for seating the main follower body  224 , a rearward narrowed portion  35  for seating the follower rearward projection  34 , a pair of side locating features  37 / 39  for seating the follower side notches  29 , and a forward notch  41  for seating the smaller forward projection  31 . 
     In each of the above variants  10 ,  100  and  200  of the magazine, the upper incorporated feed lips are physically connected and reinforced at the rear of the magazine. In comparison to previous magazine designs, in which the feed lips weren&#39;t connected and the follower extended between them to the rear of the magazine as a single piece, the reinforced construction of the feed lips avoids instances of swelling which, in extreme cases, allows rounds slip out the top of the magazine. Furthermore, and by connecting the feed lips in the manner provided in the present invention, instances of swelling is eliminated. 
     Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, and without deviating from the scope of the appended claims. The detailed description and drawings are further understood to be supportive of the disclosure, the scope of which being defined by the claims. While some of the best modes and other embodiments for carrying out the claimed teachings have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims. 
     The foregoing disclosure is further understood as not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims. 
     In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. 
     Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, and the like) are only used to aid the reader&#39;s understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other. 
     Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader&#39;s understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification. 
     It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.