Patent Publication Number: US-11029111-B2

Title: Firearm barrel lock

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/849,577, filed May 17, 2019, in the United States Patent Office. All disclosures of the document named above are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     There is a need for a practical, easy to use lock for a firearm. Such a lock will, when engaged prevent discharge of the firearm and when not engaged will allow the use of the firearm without hindrance. The art includes earlier firearm locks, such as McLaren U.S. Pat. No. 6,560,910. The present invention offers substantial advantages over the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention is a lock for a firearm which may be inserted into the barrel of the firearm. The firearm includes a chamber adjacent a barrel with the chamber having a diameter which is greater than the diameter of the barrel. The lock of the present invention includes a user manipulatable proximate end and a distal end which responds to the user manipulation by transiting between a lock condition and an unlock condition. The proximate and distal ends of the lock are coupled by a hollow shaft in which a rod is supported. The length of the hollow shaft is sufficient to place the distal end of the lock within the chamber of the firearm when the proximal end extends beyond the length of the barrel. The rod cycles between two positions, in one, a lock condition and the other an unlock condition. The rod cycles in response to user manipulation of the proximate end. 
     In one embodiment the rod may translate toward the distal end in response to user manipulation of the user manipulatable end. The distal end includes a flexure pawl which extends from the distal end of the rod adjacent an aperture in the hollow shaft. In the unlock condition the flexure pawl presents a surface which exhibits a continuation of the surface of the hollow shaft. The rod includes a first portion, at the extreme distal end, with one diameter and an adjacent portion with a greater diameter. The flexure pawl engages the rod and, as the rod translates toward the distal end, the flexure pawl engages the portion of the shaft of greater diameter. This causes the surface of the pawl to above the surface of the hollow shaft. When this action occurs with the distal end of the lock located in the chamber of the firearm, the motion of the pawl causes the surface of the pawl to engage an interior ridge of the firearm located at the junction of the chamber and barrel. Engagement of the pawl with the ridge of the firearm prevents extraction of the shaft from the barrel of the firearm, effectively locking the firearm against use. With the lock in this lock condition, translation of the rod toward the proximate end results in the flexure pawl no longer engaging the greater diameter portion of the rod. Engagement of the pawl with the portion of the rod of lesser diameter allows the pawl retract to be again flush with the surface of the shaft so as to no longer engage in a ridge in the firearm. In this configuration the distal end and shaft may be withdrawn from the barrel of the firearm allowing normal use. 
     In another embodiment, actuation of the lock (produced by user actuation) causes the rod within the hollow shaft to rotate between the lock and unlock conditions. The distal end of the rod has an oval cross-section having a major and minor axis. At the distal end the rod supports two tabs, each extending less than 180° about the rod and held in engagement with the surface of the rod by a garter like spring. In the unlock condition the tabs engage with the minor axis of the rod. With the tabs engaged with the minor axis of the rod, the surface of the tabs is co-extensive with the surface of the hollow shaft. When the rod rotates about 90° the tabs come into engagement with the major axis. As a result of engagement with the major axis the tabs move away from the centerline of the rod. That motion causes the surfaces of each of the tabs to extend beyond the surface of the hollow shaft and engage with the interior ridge of the firearm. The engagement of the tabs and ridge prevent withdrawal of the shaft and prevents normal use of the firearm. With the lock in this lock condition rotation of the rod by another 90° allows the tabs to again engage with the minor axis of the rod so the tabs retract to lie flush with the surface of the hollow shaft and disengage with the ridge in the firearm allowing the shaft to be withdrawn so the firearm is again in condition for normal use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is an exploded view of one embodiment of the invention; 
         FIG. 2  is a cross-section of the device of  FIG. 1 ; 
         FIG. 3  is a perspective view of the device of  FIG. 1 ; 
         FIG. 4  is a cross-section of the distal end of the device of  FIG. 1  in an unlock condition; 
         FIG. 5  is a cross-section of a firearm and located therein the distal end of the device of  FIG. 1  in a lock condition; 
         FIG. 6  shows variations on the flexure element of the device of  FIG. 1 ; 
         FIG. 7  is a perspective view of another embodiment of the invention; 
         FIG. 8  is a cross-section of the device of  FIG. 7 ; 
         FIG. 9  is a cross-section of the distal end of the device of  FIG. 7 ; 
         FIGS. 10 and 11  are perspective and section of the distal end of the device of  FIG. 7  in the unlock condition; 
         FIGS. 12 and 13  are perspective and section of the distal end of the device of  FIG. 7  in the lock condition. 
         FIG. 14  show a typical gun lock according to one embodiment juxtaposed to a typical firearm; and 
         FIG. 15  shows a typical gun lock according to the invention inserted in a firearm. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       FIG. 1  is an exploded view of a first embodiment of the invention. At a proximal end are two half base housings  15 . The housings  15  are pinned and fused with attachment to the base receiver cap  16 . Contained within the housings  15  are a set of four cams  1 , each of which can rotate on the linear actuating spindle  14 . Each cam  1  has a notch  19  which establishes a coded position for that cam. When all four cams  1  are in their coded position, each of the notches  19  will register so that a comb  13  is allowed to translate. A knob  3  is pressed onto the spindle  14  and pinned by the pin  51 . A spring release tab  2  is fixed to the comb  13  and a spring  18  is attached to the comb  13  and the housing  16  to provide a force to stabilize the tab  2  within the notch  20  to stabilize the knob  3  against motion. 
     When the cams  1  achieve their coded condition and the comb is free to translate the user may apply a force to withdraw the tab  2  from the notch  20 . When the tab  2  is withdrawn from notch  20  the knob  3  is free to rotate in response to user actuation. Rotation of the knob  3  produces rotation of the spindle  14 . The presence of the threads on the spindle  14  produce translation of the shaft  21  from rotation of the spindle  14 . Located within the shaft  21  is the translation shaft or rod  4  which can translate forward (away from knob  3 ) and back (towards the knob  3 ) in response to translation of the shaft  21 .  FIG. 2  is a section of apparatus of  FIG. 1  showing the relation of spindle  14  and shaft or rod  4  within the shaft housing  5 . At the distal end  40  of the translation shaft or rod  4  is the pawl  41 , shown in greater detail in  FIG. 4 . 
     The pawl  41  fits into the end cap  42 . The end cap  42  is the leading end of the lock to enter the barrel. The end cap  42  is made of resilient material that is less hardened than the barrel so that introduction of the lock into the firearm is not detrimental to the firearm. As seen in  FIGS. 1 and 4 , the distal end of the translation shaft  4  has a first reduced region  45  and a second reduced region  46 . Each of the reduced regions  45  and  46  has a diameter smaller than the upstream region so that (see  FIG. 4 ) the translation shaft  4  exhibits a first shoulder  48  (between the translation shaft  4  and first reduced region  45 ) and a second shoulder  47  between the first and second reduced regions  45  and  46 . The flexure pawl  41  has a pair of wings  51 - 52  which fit within a slot  53  in the tubular surface of the shaft housing  5 . The interior of each of the wings  51 ,  52  has a diameter which first reduces to a minimum and then increases at increasing distances from the proximal edge of the wing toward the distal end producing an edge  53  of the smallest diameter. When the translation shaft  4  translates toward the distal end the edge  53  first intersects shoulder  47  and then rides up the shoulder  47 . As a consequence, the surfaces of wings  51  and  52  jut above the surface of the shaft housing  5 . When inserted in the barrel of a firearm (see  FIG. 5 ) the distal end of the lock extends through the barrel  101  and into the chamber of the firearm. The chamber of the firearm and barrel intersect in the edge  105 . When the lock is inserted into the chamber of the firearm in an unlock condition (translation shaft  4  in the retracted position), and thereafter transitioned to a lock condition (by motion of the tab  2  and rotation of the knob  3 ), the surface of the wings  51 ,  52  jut above the surface of shaft  5  and intersect with the edge  105  of the firearm. Thereafter, the comb  2  is retracted so the tab is again inserted into the slot  20  in the knob  3 . In this condition the lock cannot be withdrawn and the firearm is incapable of discharging. To transition the lock to the unlock condition, the cams must again be positioned into their coded position so the comb  13  can be shifted forward allowing the tab  2  to be withdrawn from the slot  20  in the knob  3 . This frees the knob  3  to rotate to translate the shaft  4  backward (toward the proximal position) moving the edge  53  past the shoulder  47  retracting the wings  51 ,  52  from intersecting the edge  105  allowing the lock to be withdrawn from the firearm. 
     The pawl  41  has wings  51  and  52  which present a continuous surface that is flush with the shaft housing  5  when the wings  51 ,  52  are withdrawn into an unlock condition. The form of the pawl illustrated in  FIGS. 1-5  can be changed to any of the forms  9 - 11  illustrated in  FIG. 6 . Different shapes illustrated in  FIG. 6  are accompanied by different force levels which are required to deploy the wings outwardly from the unlock to the lock condition. The pawl can be made from stainless steel, optimally a 17-4 PH or 17-7 PH and can be made with varying spring flexure lengths and thicknesses as illustrated in  FIG. 6 . In particular the forms represented at  9  and  10  each include back relied. The back relief at  10  represents a longer spring section than that referenced at  9 . The longer spring section reduces the force required of the translation shaft or rod  4  to deploy the two pawls. The form of the pawl represented at  11  does not include any back relief at all. The absence of back relief requires more force to achieve the transitional movement. Consequently, the sequence of the forms  11 ,  9  and  10  represent a sequence of reduced force required to achieve the transitional movement. 
     A second embodiment is illustrated in  FIGS. 7-13 . The embodiment of  FIG. 1  operates between the lock and unlock condition by translation of the shaft  4 . The embodiment of  FIG. 7  has a similar shaft which is fixed and released by the use of cams  1 - 4 , knob  3 , comb  13  having tab  2  interacting with slot  20  just as the embodiment of  FIG. 1 . However, shaft  4  of  FIG. 1  is replaced by shaft  17  and the flexure pawl  41  is replaced by pawl  12 . Shaft  17  operates the pawl  12  between a lock and unlock condition by rotation of the shaft  17 . In other words, with the cams  1 - 4  in their coded positions, the comb  13  is free to move forward freeing the tab  2  allowing knob  3  to rotate. Rotation of knob  3  causes spindle  14  to rotate. In the embodiment of  FIG. 7  rotation of spindle  21  produces rotation of shaft  17 . As seen in the section of  FIGS. 8 and 9  the pawl  12  includes two segments,  110 , each secured about the shaft  17  by a spring  111 . The shaft  17  has an oval cross section—compare  FIGS. 11 and 13 . In  FIG. 11  (showing the unlock or retracted condition) the segments  110  fit around the shaft  17  separated by a minor axis of the oval. In  FIG. 12  the segments  110  are separated by the major axis of the oval. When the segments  110  are separated by the minor axis of the oval the outer surface of the segments are colinear with the surface of the housing  5 . On the other hand the increased length of the major axis of the oval is such that when the segments surround the major axis (as seen in  FIGS. 12 and 13 , the surface of the segments  110  protrude beyond the surface of the housing  5  to such an extent that the segments impact the edge  105  at the intersection of barrel and chamber of the firearm. If, at this time the lock is inserted into the chamber and locked with the major axis of the shaft  17  separating the segments  110 , then the segments will prevent the segments from passing the edge  105 , i.e., the lock cannot be withdrawn from the firearm and so the firearm cannot be discharged. If the tab  2  is moved out of the slot  20  and the knob rotated so the minor axis of the shaft  17  separates the segments  110 , then the surface of the segments will retract to lie colinear with the surface of the housing  5  allowing the segments to pass the intersection of the barrel and chamber and allowing the lock to be withdrawn from the firearm. 
     The pawl design represented in  FIGS. 10-13  show how two independent elements can be held together by a spring and actuated by a rotary cam mechanism (the shaft  17 ). 
       FIGS. 14 and 15  illustrate a typical gun lock  200  (which can represent either the gun lock of  FIGS. 1-3  or the gun lock of  FIGS. 7-13 ).  FIG. 14  shows the gun lock  200  adjacent but not inserted into the firearm  300  whereas  FIG. 15  shows the gun lock  200  inserted into the firearm  300 . 
     The foregoing is a description of two specific embodiments of the invention but it is apparent that many variations may be made within the spirit and scope of the invention which is expressed within the scope of the attached claims.