Patent Publication Number: US-2022214125-A1

Title: Firearm Safety Feature

Description:
RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. application Ser. No. 16/821,209, filed on Mar. 17, 2020 by the same inventor, which is a continuation of U.S. application Ser. No. 15/221,220, filed on Jul. 27, 2016 by the same inventor, which claims the benefit of priority to U.S. Provisional Patent Application No. 62/197,937, filed Jul. 28, 2015 by the same inventor and entitled “Firearm Safety Feature”, all of which are incorporated herein by reference in their respective entireties. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates generally to firearms, and more particularly to safety features for firearms. 
     Description of the Background Art 
     Firearms are utilized for many applications including, but not limited to, hunting, target shooting, and home-defense. Firearms are designed to fire a projectile at a high rate of speed and are, therefore, very dangerous. Thus, safety is a primary concern when manufacturing and using firearms. A safety is a mechanical device that prevents unintended discharge of the firearm. Prior art safeties depend on other parts of the firearm in order to function properly. If one of these parts is broken, the safety will not function properly and the firearm may fire unintentionally. 
     For example, the US M1911 pistol is typically carried with the hammer cocked and the safety on. Carrying it in this manner has proven over the last 100+ years to be relatively safe, however, any mechanical device can fail due to spontaneous failure or improper assembly. 
     SUMMARY 
     The present invention provides safeguards, in addition to the traditional thumb safety, against the pistol firing unintentionally in the event of spontaneous part(s) failure due to, for example, an unintended impact upon the hammer or other part(s). It also increases safety in the event of improper assembly of the pistol, which could cause the sear pin to come out to the right side of the pistol, causing the sear to fail at holding the hammer in the cocked position. 
     An example firearm safety feature includes a firing pin, a hammer operative to impact the firing pin, a sear operative to engage the hammer such that the hammer is prevented from impacting the firing pin, a trigger operative to disengage the sear from the hammer, allowing the hammer to impact the firing pin, a safety switchable between a safe position and a firing position. The hammer includes an arresting surface and a portion of the safety positioned to prevent the sear from disengaging the hammer when the trigger is depressed includes a complementary arresting surface. The arresting surface and the complementary arresting surface become positively engaged when the safety is engaged and the sear fails to engage the hammer. In a more particular embodiment the arresting surface is defined by a first angled cut in the hammer and the complementary arresting surface is defined by a second angled cut in the portion of the safety. The first angled cut and the second angled cut are equiangular. 
     Another example firearm safety feature includes a firing pin, a hammer operative to impact the firing pin, a sear operative to engage the hammer such the hammer is prevented from impacting the firing pin, a trigger operative to engage the sear such that when the trigger is depressed the sear disengages from the hammer to allow the hammer to impact the firing pin, and a grip safety preventing the trigger from engaging the sear absent a firing grip on the firearm. The hammer includes an arresting surface and the grip safety includes a complementary arresting surface adjacent the hammer when the hammer is in a cocked position. The arresting surface and the complementary arresting surface become positively engaged when the grip safety is in a safe position and the sear fails to engage the hammer. In a particular embodiment, the hammer defines a travel path before impacting said firing pin, and the travel path passes through the complementary arresting surface when the grip safety is in a safe position. The arresting surface and the complementary arresting surface are parallel when the hammer contacts the grip safety along the travel path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the following drawings, wherein like reference numbers denote substantially similar elements: 
         FIG. 1  is a cutaway drawing of an example prior art firearm; 
         FIG. 2  is cutaway drawing of the firearm of  FIG. 1 ; 
         FIG. 3  is a diagram showing various parts of the firing mechanism and thumb safety of the firearm of  FIG. 1 ; 
         FIG. 4  is a photograph of an example prior art cutaway firearm showing the thumb safety in an engaged configuration; 
         FIG. 5  is a photograph of the firearm of  FIG. 4  showing the thumb safety in an unengaged configuration; 
         FIG. 6A  is a diagram showing various parts of an example firearm including a thumb safety according to the present invention; 
         FIG. 6B  is a diagram showing various parts of the firearm of  FIG. 6A  after failure of a sear; 
         FIG. 7A  is a diagram showing various parts of an example firearm including a grip safety according to the prior art in an engaged configuration; 
         FIG. 7B  is a diagram showing the firearm of  FIG. 7A  showing the grip safety in an unengaged configuration; 
         FIG. 8A  is a diagram showing various parts of an example firearm including a grip safety according to the present invention in an engaged configuration; and 
         FIG. 8B  is a diagram showing various parts of the firearm of  FIG. 8A  after failure of a sear. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a cutaway drawing of an example firearm  100 . Firearm  100  is a typical handgun, particularly a US M1911 pistol. While the M1911 pistol is used as an example, the present invention is not limited only to pistols of this type. Indeed, the designs can be adapted for use in any applicable firearm. 
       FIG. 2  is a cutaway drawing of firearm  100  in an alternate configuration, particularly in an unloaded and unlocked condition with the slide held open. 
       FIG. 3  is a diagram showing various parts of the firing mechanism and thumb safety of firearm  100 . Applying the safety blocks a sear  302 . When pulling a trigger  308  on the  1911 , trigger  308  acts upon the bottom of sear  302 , causing the bottom of sear  302  to move rearward. As sear  302  is mounted via a pivot pin  310  that is roughly vertically central to its body, when the bottom of sear  302  moves rearward, the top of sear  302  moves forward, disengaging from a sear notch  304  in a hammer  306 , allowing hammer  306  to fall and contact a firing pin  322 , which then impacts the cartridge and causes the cartridge to fire. When pulling trigger  308  with the safety on, the bottom of sear  302  is blocked from any rearward movement by a lug  314  integral to the safety, so the pistol will not fire. 
     Note that when the safety is engaged, it pivots or swings up, presenting integral lug  314  that protrudes inward, which blocks sear  302  as described above. This safety can only be engaged when hammer  306  is cocked. Hammer  306 , pivoting on its own pin  312 , comprises an upper portion, containing the part that actually contacts firing pin  322  and has serrations to increase friction for thumb-cocking, and the lower portion, which contains sear notch  304 , which, in concert with the tip of sear  302 , acts to hold hammer  306  in the cocked position. The safety can only be engaged with hammer  306  in a cocked position, because, in the cocked position, a radial clearance cut in the bottom portion of hammer  306  provides space for safety lug  314  to occupy when the safety is pivoted up into the “safe” position. In this “safe” position, lug  314  does appear to be in the way of hammer  306  falling, should a spontaneous failure of sear  302 , sear pin  310 , or sear notch  304  of hammer  306  occur. However, the relationship between cocked hammer  306  and safety lug  314  is such that if hammer  306  should fall, it will simply cam safety lug  314  out of the way and continue to fall onto firing pin  322 . The safety&#39;s “on” and “off” positions are detented by a spring plunger, and the effort to move the safety up and down varies greatly from pistol to pistol and can be tuned to be heavy or light. In a pistol with heavy detents, this detent action, making downward movement of the safety require greater effort, could constitute enough resistance to the safety&#39;s movement to retard the fall of hammer  306  enough to prevent firing. However, in many pistols it will not, and, in any event, the safety detent effort is not and should not be relied upon as a safety feature. 
       FIG. 4  is a photograph of an example prior art cutaway firearm  400  showing the thumb safety in an engaged configuration. 
       FIG. 5  is a photograph of firearm  400  showing the thumb safety in an unengaged configuration. 
       FIG. 6A  is a diagram showing various parts of an example firearm  600  including a thumb safety according to the present invention. The present invention includes alterations to the previously discussed safety system. Particularly, it includes differently shaped hammer  606  and safety lug  614 . Even more particularly, hammer  606  includes an arresting surface  624  and safety lug  614  includes a complementary arresting surface  626 . When contacting each other, these arresting surfaces create a positive engagement, preventing hammer  606  from falling. 
     In a traditional M1911, such as firearm  100 , when the safety is engaged, it rotates upward and, subsequently, the safety lug rotates upward as well. When the hammer falls due to a failure of the sear, sear pin, or sear notch of the hammer, the hammer applies a rotational force on the safety lug, which rotates downward, and the safety disengages. 
     The present design prevents this by orienting the arresting surfaces in a way that eliminates the rotational force on safety lug  614 . When the arresting surfaces come into contact, the resulting force on safety lug  614  is predominately radial, as opposed to tangential or rotational. Indeed, the rotation of hammer  606  acts to lift safety lug  614  toward hammer  606  as opposed to rotating it down and out of place. While a particular embodiment of the present invention is detailed below, it should be noted that alternate features can be used without departing from the scope of the present invention. 
     In the example design the radial cut in the bottom of hammer  606 , provided to give safety lug  614  clearance, includes a right-angle cut or notch defined partially by arresting surface  624 . Safety lug  614  also includes a right-angle cut defined partially by complementary arresting surface  626 , so, should hammer  606  fall with the safety on, it is not possible for hammer  606  to simply bump or cam the safety to the off position and continue falling. Indeed, the hammer  606  and safety lug  614  will become hooked together, and due to the positive angles of the engagement surfaces, this engagement is very secure. Optionally, the engaging surfaces can be textured, coated, and/or otherwise adapted to increase the coefficient of friction between the surfaces, which makes the engagement even more secure. Under the influence of a hammer spring  620  on hammer  606 , pushing it forward, hammer  606  and safety lug  614  tend to pull themselves into this positive engagement. This positive arresting of the fall of hammer  606  occurs about a third to half-way between the “cocked” and fully-forward positions of hammer  606 . 
       FIG. 6B  is a diagram showing various parts of the firearm of  FIG. 6A  after failure of a sear. Arresting surface  624  and complementary arresting surface  626  are positively engaged, preventing hammer  606  from falling and striking a firing pin  622 . 
       FIG. 7A  is a diagram showing various parts of an example firearm  700  including a grip safety according to the prior art in an engaged configuration. Absent a firing grasp on the pistol, a grip safety  702 , under the influence of a flat spring (not shown) inside the pistol&#39;s handle portion, pivots to the rear (about a pivot shaft  704  of the thumb safety). When pivoted to this position, a horizontal, forward-reaching arm  706  integral to the grip safety is pivoted downward and blocks the rearward movement of a trigger  708 . While grip safety  702  prevents rearward movement of the trigger from disengaging a sear  710  from a hammer  712 , and, thus, prevents unintended firing of firearm, someone skilled in the art will realize that grip safety  702  will not prevent unintended firing in the event of a failure of sear  710 . 
       FIG. 7B  is a diagram showing the firearm of  FIG. 7A  showing the grip safety in an unengaged configuration. When a firing grasp is applied to the handle of firearm  700 , grip safety  702  pivots forward, and forward reaching arm  706  is raised up and out of the path of trigger  708 . In this position, trigger  708  can move rearward, rotating sear  710  about a sear pin  714  (assuming a safety lug  716  is in the firing position), thereby causing the pistol to fire. There is nothing about grip safety  702  that acts upon hammer  712  or blocks its path in any way. 
       FIG. 8A  is a diagram showing various parts of an example firearm  900  including a grip safety  902  according to the present invention in an engaged configuration. Grip safety  902  includes alterations from the traditional grip safety. Particularly grip safety  902  includes a hook  904 , which introduces a relationship between grip safety  902  and a hammer  906 . In the example embodiment, hook  904  is fashioned into the “beavertail type”. In alternate embodiments hook  904  can be altered or substituted for specific applications. Hook  904  includes an arresting surface  908 , and hammer  906  includes a complementary arresting surface  910 . When these surfaces contact each other, they create a positive engagement, preventing hammer  906  from falling. The positive engagement arrests the forward movement of hammer  906  in the event of a spontaneous failure of a sear  912 , a sear pin  914 , or a sear notch  916  of hammer  906 . 
     Absent a firing grasp on firearm  900 , as stated above, a forward-protruding horizontal arm (not shown) of grip safety  902  blocks movement of a trigger  918 . In the example design, grip safety  902  has an added portion  920  that presents a roughly vertical surface  922  behind cocked hammer  906 . This added portion envelops hammer  906  at its rear, and vertical surface  922  has a horizontal cut  924  in it. Hammer  906  includes a raised hook  926  at the very rear of the “spur” or serrated thumb-cocking surface. When grip safety  902  is at rest in its “out” or “engaged” position, that is, when there is nothing pushing it inward, not only is trigger  918  blocked as per the original design, but the newly introduced rear vertical surface  922  with horizontal cut  924 , in this at-rest position, is pivoted slightly upward and forward, so that raised hook  926 , at the rear of the spur of hammer  906 , is in an interference relationship with horizontal cut  924  in vertical surface  922 . In other words, the arc described by raised hook  926 , in the event of hammer  906  falling due to a spontaneous failure of sear  912 , sear pin  914 , or sear notch  916  on hammer  906 , interferes with horizontal cut  924  in vertical surface  922  of grip safety  902 , effecting a positive engagement of the two parts. This engagement positively arrests the forward fall of hammer  906 , preventing an unintentional discharge. 
     Example grip safety  902 , in that it by necessity envelops hammer  906  more than previous designs, also affords hammer  906  more protection against an unintentional blow, which could cause the engagement between hammer  906  and sear  912  to fail. Further, as it closes the gap that is normally present between a typical hammer and grip safety, the likelihood of getting an article of clothing snagged in the gap, interfering with the drawing of the pistol, is greatly reduced. 
       FIG. 8B  is a diagram showing various parts of the firearm of  FIG. 8A  after failure of a sear. Horizontal cut  924  and raised hook  926  are positively engaged, preventing hammer  906  from falling and striking a firing pin  928 .