Abstract:
A lockable safety selector switch adapted to replace a manufacturer&#39;s original safety selector switch for a firearm having a selector detent pin with a tip. The lockable safety selector switch has a body adapted to selectively orient between a SAFE position that prevents the firearm from firing and a FIRE position that allows the firearm to fire, and a locking mechanism configured to operatively associate with the firearm selector detent pin to selectively lock the body in the SAFE position. The lockable safety selector switch is configured such that the firearm requires no modification for the lockable safety selector switch to replace the original safety selector switch.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/556,524, entitled RIFLE RECEIVER SELECTOR SWITCH LOCKING APPARATUS AND METHOD, filed on Nov. 7, 2011. The disclosure of the above application is incorporated herein by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    This invention relates principally to a lockable firearm safety selector switch, and more particularly to a novel lockable firearm selector switch that is capable of replacing the non-lockable safety selector switch in the receiver of an AR15 rifle or other similar designs, while requiring no modifications to the firearm receiver. 
         [0004]    It has become increasingly important for the purposes of theft prevention and public safety, to hinder the rapid use of a firearm that is otherwise in a stored condition. At least from a public perception standpoint, this has become particularly important for semiautomatic and assault weapon firearms. While no system is foolproof, a device or system that at least deters the rapid deployment and use of a firearm that would otherwise be amenable to such use is desirable. 
         [0005]    One pervasive and very successful assault weapon widely distributed in the worldwide market is the fully automatic M16 rifle and its semiautomatic (civilian or sport) version, the AR15. Millions of these rifles and their variants have been produced and continue to be produced and utilized throughout the world. One significant aspect of these rifles is the designed and specified interchangeability of the rifle&#39;s individual components, and each manufacturer of the AR15 must produce its rifles to meet these interchangeability specifications. That is, the rifle has been designed for maximum interchangeability of the vast majority of the rifle components such that, for example, a trigger assembly from one AR15 can be utilized in a different AR15 simply by swapping the components between the two firearms. With particular regard to the present invention, the AR15 share a common and interchangeable set of safety selector switches. Each AR15 has a safety selector switch. Unfortunately, none of the original equipment manufacturer (“OEM”) safety selector switches are lockable. 
         [0006]    It is desirable, therefore, to devise a safety selector switch for a firearm, and in particular for an AR15 rifle, that is interchangeable with the OEM safety selector switch. In addition, it is further desirable to devise such a lockable safety selector switch that requires no modification to the firearm&#39;s receiver to either install or operate. 
         [0007]    While the preferred embodiment of the present invention is directed to a lockable safety selector switch for an AR15 rifle, the invention is equally applicable to other models firearms, both rifles and hand guns. 
         [0008]    As will become evident in this disclosure, the present invention provides benefits over the existing art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The illustrative embodiments of the present invention are shown in the following drawings which form a part of the specification: 
           [0010]      FIG. 1  is a side view of portion of a receiver of a firearm having a lockable safety selector switch of one embodiment of the present invention; 
           [0011]      FIG. 2  is a side view opposite of  FIG. 1  of a portion of a receiver of a firearm having a lockable safety selector switch of one embodiment of the present invention, and having a key engaged with the switch; 
           [0012]      FIG. 3  is an exploded partially transparent perspective view of a lockable safety selector switch of one embodiment of the present invention, showing the interaction of a key and a firearm selector detent pin with the selector switch; 
           [0013]      FIG. 4  is a partially transparent perspective view of the lockable safety selector switch of  FIG. 3  in a fully assembled condition, and interacting with a firearm selector detent pin; 
           [0014]      FIG. 5  is another partially transparent perspective view of the lockable safety selector switch of  FIG. 3  in a fully assembled condition, showing the selector switch engaged with a key, a firearm selector detent pin and a firearm trigger arm; 
           [0015]      FIG. 6  is a perspective view of the movable detent of the lockable safety selector switch of  FIG. 3 ; 
           [0016]      FIG. 7  is a plan view of the movable detent of the lockable safety selector switch of  FIG. 3 ; 
           [0017]      FIG. 8  is a perspective view of the detent positioning cam of the lockable safety selector switch of  FIG. 3 ; 
           [0018]      FIG. 9  is a another perspective view of the detent positioning cam of the lockable safety selector switch of  FIG. 3 ; 
           [0019]      FIG. 10  is a partially transparent side view of the lockable safety selector switch of  FIG. 3  in a fully assembled condition in an unlocked condition and interacting with a firearm selector detent pin; 
           [0020]      FIG. 11  is a partially transparent side view of the lockable safety selector switch of  FIG. 3  in a fully assembled condition in a locked condition and interacting with a firearm selector detent pin; 
           [0021]      FIG. 12  is a partially cut away front sectional view of the lockable safety selector switch of  FIG. 3  positioned within a firearm receiver and interacting with the firearm&#39;s selector detent pin, with an external key engaging the switch, the switch in an unlocked condition; and 
           [0022]      FIG. 13  is a partially cut away front sectional view of the lockable safety selector switch of  FIG. 3  positioned within a firearm receiver and interacting with the firearm&#39;s selector detent pin, with an external key engaging the switch, the switch in a locked condition; 
           [0023]      FIG. 14  is an end view of the switch body of the lockable safety selector switch of  FIG. 3 . 
       
    
    
       [0024]    Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0025]    In referring to the drawings, an embodiment of the novel lockable safety selector switch  10  for a receiver R ( FIGS. 1 ,  2 ) of a firearm, such as for example an AR15, of the present invention is shown generally in  FIGS. 3-13 , where the present invention is depicted by way of example, and is shown in  FIGS. 3-5  and  10 - 13  to interact with a firearm selector detent pin P having a tip T associated with a compression spring S, and with a trigger arm A ( FIGS. 5 ,  12 - 13 ), which are all located within the receiver R. As can be seen, the switch  10  comprises a switch body  12 , a movable detent  14 , a detent positioning cam  16  and an assembly cap  18 , the components inside the body  12  comprising a locking mechanism. The switch body  12  is configured to match where necessary the outer surface configuration of the firearm manufacturer&#39;s original standard, or “spec”, selector switch for a desired firearm; here, an AR15. This facilitates the replacement of a standard selector switch with a novel lockable safety selector switch  10  of the present invention without any modification to the firearm or the switch  10 . However, while a standard selector switch is typically solid metal, the selector switch  10  of the present invention is hollow and comprises locking components contained within the switch body  12  to facilitate its locking function. 
         [0026]    Referring to  FIG. 3 , the switch  10  comprises a cylindrical shaft  20  having a central axis X. A coaxial generally cylindrical central portion  22  that is coaxial with but has a diameter slightly less than the shaft  20  extends approximately along the central third of the shaft  20 . The central portion  22  has a flat surface  23  along one side. A lever  24  extends laterally from one end of the shaft  20 , and is configured to allow the firearm operator to rotate the switch  10  about the axis X when the switch  10  is properly positioned within the receiver R of a firearm. Opposite the lever  24 , a cylindrical bore  26 , also having its central axis at X, extends approximately one third of the way into the shaft  20 . The bore  26  has an open distal end  28  and a closed proximal end  30  and is configured to house the cam  16  freely rotatable there within. The bore  26  does not extend into the central portion  22 . Female threads  32  are formed in the distal end  28  of the bore  26 . Further, a small conical bore  34  ( FIGS. 3-4 ,  12 - 14 ), centered upon and coaxial with the axis X, extends from the proximal end  30  of the bore  26  further into the shaft  20  in the direction of the lever  24 , the conical bore  34  having its apex directed away from the bore  26 . In addition, a plug or other cover (not shown) can be fashioned of rubber or some other suitable material such that the plug or cover can be removably secured in the cap  18  to seal the interior of the switch body  12  from the elements, including dust, grime and moisture. 
         [0027]    A radial arcuate slot  50  ( FIGS. 3-5 ) is formed in a portion of the shaft  20  near the distal end  28  of the bore  26 . The slot  50  has a generally concave profile that extends for a distance of approximately one fourth the circumference of the shaft  20 . The slot  50  terminates at one end at a generally cylindrical throughbore  52  and at the other end at a concave depression  54 , where the outer diameters of the bore  52  and the upper edge of the depression  54  are both equal to the width of the slot  50 , and there between form an arcuate groove  56  along the bottom of the slot  50 . Further, the bore  52  and depression  54  align with the slot  50  such that the upper edge of the slot  50  smoothly integrates into the upper edges of the bore  52  and the depression  54 . The bore  52  penetrates from the outer surface of the shaft  20  through to the bore  26  and has parallel ledges  53  formed on opposing sidewalls below the level of the slot  50 . The depression  54 , though not a throughbore, extends further into the shaft  20  than the groove  56 . The width of the slot  50  is such that the slot  50  can closely yet freely receive the tip T of the selector detent pin P at any position along the full length of the slot  50  when the switch  10  is properly installed in the receiver R (see  FIGS. 2 ,  12 - 13 ), and the selector detent pin P can closely yet freely extend into either of the throughbore  52  or the depression  54 . 
         [0028]    Referring now to  FIGS. 6 and 7 , it can be seen that the movable detent  14  is cylindrical, with a generally concave lower end  60  and an opposing generally flat upper end  62 . A sinusoidal groove  64  along the outer edge of the lower end  60  extends from the outer surface of the movable detent  14  to the inner concave surface of the lower end  60 . The groove  64  is shaped to conform to shape of the tip T of the selector detent pin P. The upper end  62  of the movable detent  14  is chamfered to form a curved rim  66  along the outer edge of the upper end  62 . Two matching parallel peripheral flats  68  are formed along opposing sides of the movable detent  14 , and extend from the lower end  60  to two matching and opposing and coplanar ledges  69  formed near the upper end  62 . The ledges  69  are configured to mate with the ledges  53  in the bore  52  at one end of the slot  50  in the shaft  20 . The flats  68  are configured to enable the movable detent  14  to fit within and slide along the curved surface of the slot  50  while the ledges  69  prevent the movable detent  14  from passing entirely through the slot  50  (see  FIGS. 3-5 ,  12 - 13 ). 
         [0029]    Referring to  FIGS. 8 and 9 , the positioning cam  16  has the general shape of a spool with a generally cylindrical central shaft  70 , and a pair of discs,  71  and  72 , of equal thickness at opposing ends of the shaft  70 . While the disc  71  is fully circular about its outer edge, it can be seen that the outer edge of the disc  72  traces an arcuate lip  79   a  of approximately two hundred forty degrees about the shaft  70 , and thereby forms a minor arcuate portion  79   b  of the disc  72  of approximately one hundred twenty degrees about the shaft  70 . The shaft  70  and the discs  71  and  72  are all coaxial about a central axis Y that runs through the center of the cam  16 . The discs  71  and  72  have outer ends,  73  and  74 , respectively, that are flat and parallel to each other. A key hole bore  75  extends generally into the center of the outer end  73  of the first disc  71  ( FIG. 3 ). On the other end of the cam  16  ( FIGS. 8-9 ), a conical detent  76  extends from of the outer end  74  of the disc  72  opposite the key hole bore  75 . The conical detent  76  is coaxial with the axis Y and has a base that is smaller in diameter than the diameter of the disc  72 . The conical detent  76  is configured to mate with and freely rotate within the conical bore  34  in the shaft  20  along the axis X such that when the detent  76  is engaged with the bore  34  the axis Y and the axis X are coaxial and there is little non-axial free play (see  FIGS. 5 ,  12 - 13 ). Of course, the conical bore  34  and corresponding conical detent  76  may be configured in other shapes, such as for example, a cylindrical bore and a matching cylindrical detent, so long as the shapes provide for axial alignment of and free rotation of the detent positioning cam  16  within the cylindrical bore  26 . Though generally cylindrical, the central shaft  70  is slightly spiral in cross-section such that the outer surface of the shaft forms a discrete radial ramp  77  with a single lip  78  located where the bottom of the ramp meets the top of the ramp around the shaft  70 . The lip  78  is generally rectangular and stretches from the first disc  71  to the second disc  72  along the shaft  70 . 
         [0030]    The assembly cap  18  ( FIGS. 3-5 ) is essentially a shortened screw that is utilized to close off and seal the bore  26  of the switch  10 . That is, the cap  18  comprises a short threaded shaft  80  and a generally flat head  82  at one end of the shaft  80 . The threaded shaft  80  is configured to mate with and screw into the female threads  32  along the inner surface at the open end of the bore  26  such that the head  82  of the cap  18  can be snugly tightened against the distal end  28  of the bore  26  in the shaft  20 . The length of the threaded shaft  80  is long enough to secure the cap  18  to the distal end  28  of the bore  26 , yet not so long as to compress or bind the cam  16  against the proximal end  30  of the bore  26  when the cam  16  is properly installed in the bore  26 . A throughbore  84  in the cap  18  is coaxial with and extends through the shaft  80  and through the head  82 . The throughbore  84  is configured to receive a shaped shaft, such as for example, an Allen wrench or a pentagonal wrench, to facilitate screwing the cap  18  into or out of the distal end  28  of the bore  26 . Further, the throughbore  84  is sufficiently wide to allow a key K to pass without hindrance through the bore  84  to the key hole  75  in the cam  16 . 
         [0031]    Referring to  FIGS. 3-5 , the switch  10  is assembled by placing the movable detent  14  through the bore  26  and into the slot  50  with the lower end  60  facing away from the axis X in the bore  26  and with upper end  62  facing toward the axis X and partially protruding into the bore  26 . The dimensions of the movable detent  14  and the peripheral flats  68  are such that detent  14  cannot pass entirely through the slot  50 , but that the peripheral flats  68  will align with and fit slidingly against the sidewalls of the slot  50  and that the orientation of the sinusoidal groove  64  is such that the groove  64  will align with the slot  50 . In this way, the tip T of the selector detent pin P can slide along the slot  50  and into the concave lower end  60  of the movable detent  14  through the sinusoidal groove  64 . The ledges  69  prevent the movable detent  14  from passing out of the bore  26  entirely through the slot  50 , and thereby hold the movable detent  14  nested in the slot  50 . 
         [0032]    The cam  16  is then placed in the bore  26  such that the conical detent  73  nests within the conical bore  34  at the end of the bore  26  in the shaft  20  and the central shaft  70  aligns with the movable detent  14  and the slot  50  such that the upper end  62  of the movable detent  14  rests against the central shaft  70 . The minor arcuate portion  79   b  of the disc  72  is directed generally upward away from the slot  50  and engages a small limiting detent  300  protruding from the end  30  of the bore  26 . The limiting detent  300  ( FIGS. 5 ,  14 ) restricts the rotation of the cam  16  within the bore  26  such that the cam  16  can only rotate along the arc defined by the non-arcuate portion of the disc  72 . 
         [0033]    The cap  18  is then screwed into the distal end  28  of the bore  26  until the cap  18  is snug. Because the key hole  75  and the bore  84  are coaxial when the switch  10  is assembled, the key hole  75  in the cam  16  is exposed through the throughbore  84  in the cap  18 , allowing a user to lock or unlock the switch  10  through the cap  18 . As previously explained, the short threaded shaft  80  of the cap  18  is just long enough to hold the cam  16  in the bore  26  without restricting the cam from freely rotating therein. When the switch  10  is properly assembled, the axes X and Y are substantially coaxial, and the cam  16  can rotate about its axis Y within the bore  26  and the key K can be inserted through the throughbore  84  and into the key hole  74  to facilitate such rotation. 
         [0034]    After assembly, the switch  10  is ready to be installed in the receiver R. To do so, the selector detent pin P and its associated spring S must first be removed from the receiver R. The switch  10  is then positioned in the receiver R in place of the original OEM selector switch. (See  FIGS. 1-2 ,  12 - 13 ). The selector detent pin P and spring S are then reinstalled in the receiver R such that the tip T of the selector detent pin P engages the slot  50  or the lower end  60  of the movable detent  14 , and the spring S thereby provides a bias that holds the selector detent pin P in engagement with the switch  10 . ( FIGS. 3-5 ,  10 - 13 ). In addition, when properly installed, the trigger arm A of the receiver R, which is capable of movement in an arc from a first lower position to a second upper position within the receiver R, positively and with a bias engages the shaft  20  at either the central portion  22  or alternatively the flat surface  23 , depending on the rotational orientation of the shaft  20  within the receiver R. ( FIG. 5 ). Importantly, when the trigger arm A engages the cylindrical central portion  22 , the trigger arm is not able to reach its second upper position and the firearm is consequently unable to fire and is therefore in a “SAFE” mode. In contrast, when the trigger arm A engages the flat surface  23 , the trigger arm is able to reach its second upper position and the firearm is consequently able to fire and is therefore in a “FIRE” mode. 
         [0035]    As can be appreciated, when a key K is inserted through the throughbore  84  and into the keyhole bore  75  to engage the cam  16  of a fully assembled selector switch  10  installed in the receiver R of a firearm, the key K can be used to rotate the cam  16  within the bore  26  of the selector switch  10  about the arc defined by the minor arcuate portion  79   b  of the disc  72 . Because the movable detent  14  is biased upward and against the ramp surface  77  of the shaft  70  of the cam  16 , the rotation of the cam  16  in one direction forces the movable detent  14  downward away from the axis Y to a first downward position at one end of the limited rotation of the cam  16  ( FIGS. 10 ,  12 ), and rotation of the cam in the opposite direction allows the movable detent  14  to extend upwards toward the axis Y to a second upward position at the other end of the limited rotation of the cam  16  ( FIGS. 11 ,  13 ). The cam  16  thereby acts as a tumbler within the locking mechanism of the switch  10 . The displacement of the movable detent  14  between the downward position and the upward position is very slight, and in one embodiment is equal to 0.025 inches. 
         [0036]    When the cam  16  is rotated clockwise about its axis Y within the bore  26  by the key K, the ramp  77  about the outer surface of the shaft  70  forces the movable detent  14  to its downward position (see  FIG. 12 ), where the sinusoidal groove  64  aligns with the groove  56  in the slot  50 . In this way, the selector detent pin P is free to move out of the throughbore  52  and out of the concave lower end  60  of the movable detent  14 , through the groove  64 , and along the groove  56  in the slot  50  to engage the depression  54  under bias from the spring S when the shaft  20  is rotated about the axis X by turning the lever arm  24 . The depression  54  is deep enough to allow the spring S to bias the tip T of the selector detent pin P to snap into the depression  54  and to releasably hold the selector detent pin P thereat, but not so deep as to prevent the lever arm from rotating back about the axis X to move the selector detent pin P out of the depression  54 . The ability of the selector detent pin P to move along the groove  56  in the slot  50  in turn allows the flat  23  of the shaft  20  to be rotated into alignment with the trigger arm A such that the trigger arm A can rotate upward in contact with the flat  23  and thereby place the firearm in its “FIRE” mode to allow the firearm to be fired. Hence, when the key K is rotated in clockwise to move the movable detent  14  to its downward position, the selector switch  10  is in an unlocked condition, and allows the user to freely select between the firearm&#39;s “SAFE” and “FIRE” modes. 
         [0037]    Conversely, when the cam  16  is rotated counterclockwise about its axis Y within the bore  26  by the key K, the ramp  77  about the outer surface of the shaft  70  allows the spring S to force the movable detent  14  to its upward position (see  FIG. 13 ), where sinusoidal groove  64  is no longer in alignment with the groove  56  in the slot  50 . In this orientation, the tip T of the selector detent pin P is extended upward under bias from the spring S into the throughbore  52  such that the tip T is locked into position within and cannot move out of the throughbore  52 . With the selector detent pin P locked in place in the throughbore  52 , the shaft  20  cannot rotate. As can be seen from  FIG. 5 , in this orientation, the flat  23  of the shaft  20  is not engaged with the trigger arm A, and the trigger arm A is thereby in the position that will not allow the firearm to be fired, i.e. the “SAFE” mode. Hence, when the movable detent  14  is in its upward position and the selector detent pin P is aligned with the throughbore  52 , the firearm will remain locked in the “SAFE” mode. 
         [0038]    While we have described in the detailed description a single configuration that may be encompassed within the disclosed embodiments of this invention, numerous other alternative configurations, that would now be apparent to one of ordinary skill in the art, may be designed and constructed within the bounds of our invention as set forth in the claims. Moreover, the above-described novel lockable safety selector switch  10  of the present invention can be arranged in a number of other and related varieties of configurations without expanding beyond the scope of our invention as set forth in the claims. 
         [0039]    For example, the firearm selector switch  10  of the present invention can be readily modified for ambidextrous use by attaching to or forming a second lever arm, opposite the lever arm  24 , at the distal end  28  of the body  20  of the switch  10  such that the second lever arm is positioned outside the receiver R when the switch  10  is assembled in the receiver R. Similarly, switch  10  can alternately be configured with the lever arm  24  as a separate component that attaches to the shaft  20  with a screw or some other similar attaching device. 
         [0040]    Additional variations or modifications to the configuration of the novel lockable safety selector switch  10  of the present invention may occur to those skilled in the art upon reviewing the subject matter of this invention. Such variations, if within the spirit of this disclosure, are intended to be encompassed within the scope of this invention. The description of the embodiments as set forth herein, and as shown in the drawings, is provided for illustrative purposes only and, unless otherwise expressly set forth, is not intended to limit the scope of the claims, which set forth the metes and bounds of our invention.