Abstract:
A bayonet lug extension for AR-15 design carbine length rifles. The bayonet lug extension positions a bayonet relative to the barrel end to have the proper amount of blade available for use.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to bayonet lugs for firearms and, more particularly, to a bayonet lug extension for an AR-15 carbine length rifle. 
         [0002]    Standard military issue bayonets designed to fit M-16 rifles will not install correctly on an AR-15 rifles that are provisioned with a carbine length barrel. Currently all AR-15 rifles with carbine length barrels have the bayonet lug located too far away from the flash suppressor resulting in the bayonet support ring resting loosely on the barrel, thereby causing undesirable radial movement. 
         [0003]    This placement also shortens the blade length protruding past the end of barrel. This results in a condition where a significant portion of the bayonet blade does not extend beyond the end of the rifle barrel, thereby limiting its effectiveness. While, other devices replace the flash suppressor with a modified flash suppressor that provides radial support for the bayonet support ring, but the substitution of flash suppressors does not correct the issue of the shortened blade length protruding past end of barrel, reducing the bayonet&#39;s functionality and effectiveness. 
         [0004]    In short, other systems fail to re-position the bayonet forward to the milspec location specified on full barrel length AR-15/M-16 rifles. Since they do not re-position the bayonet forward to the mil spec position on the rifle, the overall length of functional bayonet blade length is reduced by up to 40%. 
         [0005]    As can be seen, there is a need for an improved bayonet mounting lug, so that bayonet will have the proper amount of blade available for use. 
       SUMMARY OF THE INVENTION 
       [0006]    In one aspect of the present invention, a bayonet lug extension, comprises 
         [0007]    a bayonet lug adapter, adapted to releaseably attach to a bayonet lug on a rifle; and a bayonet receiver lug, adapted to releaseably attach to a bayonet lug groove defined in an end of a bayonet handle; wherein said bayonet lug adapter and said bayonet receiver lug are spaced apart on said bayonet lug extension such that a support ring on said bayonet handle may be received in a flash suppressor of said rifle. 
         [0008]    In another aspect of the invention, the bayonet lug adapter further comprises a latch plate pivotally attached to the bayonet lug adapter, and the latch plate is releaseably engageable with a bayonet lug slot on said bayonet lug. 
         [0009]    The latch plate may further comprise a protrusion releaseably engageable with the bayonet lug slot. In certain embodiments, a spring biases the latch plate protrusion for engagement in the bayonet lug slot. 
         [0010]    In other aspects of the invention, the bayonet lug adapter further comprises a substantially T-shaped slot, wherein the T-shaped slot is adapted to receive said bayonet lug of the rife. 
         [0011]    In another aspect, the bayonet lug extension further comprising a spacer interposed between said bayonet lug adapter and said bayonet receiver lug. In some embodiments, the bayonet lug adapter, bayonet receiver lug and the extension spacer comprise a unitary body. 
         [0012]    According to another aspect of the invention a bayonet lug extension comprises: a bayonet lug adapter, having a T-shaped slot defined in a top surface of the bayonet lug adapter, a slot defined in an outer lateral surface of the bayonet lug adapter, and a latch plate pivotally received in the slot. An extension spacer operatively connects the bayonet lug adapter with a bayonet receiver bracket. The bayonet receiver bracket comprises a bayonet receiver lug adapted to receive attachment of an end of a bayonet handle. 
         [0013]    In other embodiments, the latch plate further comprises a protrusion at a top end of the latch plate, wherein the protrusion is selectively positioned between a latched state and a released state. In the latched state the protrusion extends into the T-shaped slot. In the released state the protrusion is withdrawn from the T-shaped slot. A spring may biases the protrusion in the latched state. 
         [0014]    In other preferred embodiments, the latch plate further comprises a latch plate finger grip at a bottom end of the plate, wherein pinching the finger grip positions the protrusion in the released state. 
         [0015]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view of an AR-15 with an embodiment of a lug extension, with bayonet affixed. 
           [0017]      FIG. 2  is a perspective view of an embodiment of a bayonet lug extension. 
           [0018]      FIG. 3  is a perspective view of the bayonet lug reversed 180 degrees from the view shown in  FIG. 2 . 
           [0019]      FIG. 4  is an exploded view of an embodiment of the bayonet lug extension. 
           [0020]      FIG. 5  is a perspective view of the bayonet lug extension in an unlatched state. 
           [0021]      FIG. 6  is a detail perspective view of the bayonet lug extension aligned for attachment to a rifle. 
           [0022]      FIG. 7  is a section detail view of the bayonet lug extension along line  7 - 7  of  FIG. 6 . 
           [0023]      FIG. 8  is a side view of a lug adaptor for the bayonet lug extension. 
           [0024]      FIG. 9  is a detail perspective view of the bayonet lug extension installed on a rifle. 
           [0025]      FIG. 10  is a section detail view of the bayonet lug extension along line  10 - 10  of  FIG. 9 . 
           [0026]      FIG. 11  is a section detail view of the bayonet lug extension along line  11 - 11  of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0027]    The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
         [0028]    Broadly, an embodiment of the present invention provides a bayonet lug extension  10  for a rifle  50 , such as the AR-15/M-16, provisioned with a carbine length barrel. The bayonet lug extension  10  of the present invention provides quick, tool free installation and removal of the bayonet lug extension  10  to the rifle  50 , while providing a solid mount for the M-16 bayonet  54 . 
         [0029]    As best seen in reference to  FIG. 1 , the bayonet lug extension  10  permits the attachment of a bayonet  54  to the rifle  50 . The bayonet lug extension  10  of the present invention properly locates a bayonet support ring  62  of the a standard M-16 bayonet  54  in proper alignment with an annular channel  64  defined at an aft end of a flash suppressor  66  attached to the end of a rifle barrel  68 . The bayonet  54  is attached to the bayonet lug extension  10 . 
         [0030]    In reference to  FIG. 2 , the bayonet lug extension  10  comprises a lug adaptor  12 , an extension spacer  38 , and a bayonet receiver bracket  40 . The lug adaptor  12  is configured to releaseably attach the bayonet lug extension  10  to the existing bayonet lug  52  of the rifle  50 . The extension spacer  38  provides spacing between the lug adaptor  12  and the bayonet receiver bracket  40 , so that a bayonet receiver bracket lug  46  is positioned, relative the barrel  68 , in order to position the bayonet support ring  62  is in proper alignment with the annular channel  64  of the flash suppressor  66 . 
         [0031]    In a preferred embodiment of the invention the extension spacer  38  is a cylindrical rod, however any shape for the spacer is suitable so that the bayonet receiver bracket  40  and bayonet receiver bracket lug  46  are positioned at the specified position on the rifle barrel  68 . In the preferred embodiment, the lug adaptor  12  comprises a bore defined through an aft face to receive the adaptor rod  38   
         [0032]    In further reference to  FIGS. 2 and 3 , the lug adaptor comprises a lug adaptor T-slot  14 , defined through an aft face of the lug adaptor  12 . The T-slot  14  is adapted to receive the existing bayonet lug  52  of the rifle  50 . The lug adaptor  12  also has a slot  20  defined along at least one side face of the lug adaptor, to pivotally receive a latch plate  26  therein. With additional reference to  FIG. 4 , latch plate  26  has a protrusion  28  that extends inwardly at a top end of the latch plate  26  and extends into the T-slot when in a latched state. A finger grip  32  is provided at a second end of the latch plate  26  and extends downwardly from slot  20  and below a lower end of the lug adaptor  12 . The finger grip  32  allows a user to position the protrusion  28  between the latched state and a released state for installation and removal of the lug extension  10  from the rifle  50 . The latch plate  26  pivots about a pin  36 , extending through a latch plate pivot hole  30 . As seen in reference to  FIG. 4 , a bore  18  may extend between a front face and the back face of the lug adaptor  12 . 
         [0033]    Further in reference to  FIG. 7 , a spring  34  is disposed in a spring shaft  24  defined transversely in the lug adaptor  12 , proximal to the slot  20 . Spring  34  urges the lower end of the latch plate  26  outwardly such that the protrusion  28  is releaseably received within the T-slot  14  via a T-slot inner cutout  22 . In a preferred embodiment of the invention, the lug adaptor is provided with a second latch plate  26  on a second side of the lug adaptor  12 , wherein the configuration of the elements are in opposed relation to the first latch plate  26 . In this manner, the latch plate protrusions  28  are in opposed relation within T-slot  14  to engage within an existing bayonet lug slot  58  on the rifle&#39;s bayonet lug  52 . With particular reference to  FIG. 5 , the user may squeeze the latch plate finger grips  32  together so as to overcome the spring  34  bias against the finger plate  26  to selectively position the finger plates between a latched state and a released state. 
         [0034]    In a preferred embodiment of the invention, the lug adaptor  12  includes a lug adaptor  16  hole to receive a first end of the extension spacer  38  in a tight press fitting engagement to securely attach the spacer  38  to the lug adaptor  12 . Alternatively, spacer  38  may be integrally formed with lug adaptor  12 . 
         [0035]    Returning now to the bayonet lug receiver bracket  40 , the receiver bracket  40  comprises a receiver bracket lug  46  that is shaped according to the existing bayonet lug  52 . The receiver bracket lug  46  includes a pair of receiver bracket latch teeth  42  extending outwardly from the lateral sides of the lug  46 . A bayonet receiver bracket latch slot  44  is defined between an inner face of the receiver bracket latch teeth  42  and an opposing surface of the bayonet receiver bracket  40 . The bayonet receiver bracket  40  may further comprise an aperture  48  to receive the extension spacer  38  in a tight press fitting engagement securely attach the receiver bracket  40  with the extension spacer  38 . In an alternative embodiment of the invention, the extension spacer  38  may be integrally formed with  43  receiver bracket  40 . As will be appreciated, in certain embodiments, the bayonet lug adapter  12 , extension spacer  38 , and the bayonet receiver bracket  40  may be formed as a unitary body. 
         [0036]    As seen in reference to  FIG. 9 , the bayonet lug extension  10  is shown attached to the existing bayonet lug  52  of the rifle  50 . With particular reference to  FIG. 10 , the existing rifle bayonet lug  52  is received within lug adaptor T-slot  14 . 
         [0037]    Protrusions  28  at the top end of the latch plates  26  extend through T-slot inner cutout  22  and into T-slot  14 . In reference to  FIG. 11 , the protrusions  28  extend into the bayonet lug slot  58  of the existing rifle bayonet lug  52  to secure the bayonet lug extension  10  to the rifle  50 . Returning to  FIG. 1 , the bayonet receiver bracket lug  46  is received within a bayonet lug groove  56  defined in an aft end of a handle of the bayonet  54 . 
         [0038]    To utilize the bayonet lug extension  10  of the present invention, a user would grasp the device  10  in one hand, and an AR-15 with a carbine length barrel in the other. Next they would slide the lug adaptor  12  over the rifle&#39;s bayonet lug  52  until the lug adaptor  12  locks into position with the engagement of protrusions  28  in the bayonet lug  52  bayonet lug slot  58 . While the forward edge face of a bayonet lug tooth  59  is angled so as to automatically separate the latch plate protrusions  28 , the user may need to pinch the latch plate finger grips  32  to fully seat the bayonet lug extension  10  on the existing bayonet lug  52 . 
         [0039]    To attach a bayonet  54  to the bayonet lug extension  18 , the user would slide the bayonet support ring  62  of an M-16 bayonet  54  over the flash suppressor  66 , while aligning the bayonet&#39;s lug groove  56  with the receiver bracket lug  46  until the handle of the bayonet  54  slides over the device&#39;s receiver bracket lug  46  and the bayonet locks into position at the specified position with the bayonet support ring  62  received with the annular channel  64  at the aft end of the flash suppressor  66 . 
         [0040]    To remove the bayonet lug adapter  10 , the user would squeeze the latch plate finger grips  32  until the protruding tips  28  of the latch plate release from the receiver bracket latch slots  44 . 
         [0041]    It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.