Patent Publication Number: US-11029114-B2

Title: Trigger mechanism for firearms

Description:
BACKGROUND 
     State of the Art 
     The present invention relates to a trigger mechanism for firearms. More specifically, the present invention relates to a trigger mechanism, with particular application for automatic and semiautomatic firearms. 
     Field of Art 
     In order to fire most firearms, the user places his or her index finger on the trigger of the weapon. As the trigger is pulled rearwardly, a hammer inside the firearm is released and either directly or indirectly (e.g., via a firing pin) strikes the primer or rim of the casing to thereby cause the powder charge to ignite and fire the bullet. For many people, use of the index finger is relatively easy and allows for a desirable firing rate. However, use of the index finger to actuate a trigger can have negative effects. 
     One disadvantage of using the index finger is that as the finger contracts and pulls the trigger, a slight rotational movement may occur in the user&#39;s hand which may cause the weapon to be deflected slightly and thereby interfere with obtaining a highly accurate shot. This is particularly true, in a high stress situation, such as where a person is subject to return fire. 
     Another disadvantage with using the index finger to actuate a trigger is that the mobility of the index finger is often reduced if the user&#39;s hand is cold. This can cause a slower reaction time and less ability to determine if the trigger has been properly pressed. While a shooter may wear a glove, the trigger guards for many firearms are small enough that they can interfere with the ability to freely use the index finger if a glove is being worn. 
     Yet another problem with the conventional location of triggers is that they are susceptible to being accidentally depressed. While good training lessens the likelihood of a person carrying a firearm with their finger immediately adjacent the trigger, every year there are numerous accidents wherein a person stumbles or slips and inadvertently squeezes the trigger. Likewise, in situations where the firearm is being used in heavily wooded surroundings, there is a risk that an errant branch, etc. may contact the trigger and cause an inadvertent discharge of the weapon if the safety is off. While proper use of the safety should prevent such accidents, they occur, nonetheless. 
     Thus, it is desirable to find a system and method for actuating a firearm which does not require use of the index finger. It is also desirable to find a system and method for actuating an automatic or semiautomatic weapon which is less susceptible to accidental discharge of the weapon. 
     SUMMARY OF THE INVENTION 
     The following summary of the present invention is not intended to describe each illustrated embodiment or every possible implementation of the invention, but rather to give illustrative examples of application of principles of the invention. 
     In some configurations, the invention may comprise a trigger body having a trigger which extends rearwardly so that the trigger can be actuated by the shooter&#39;s thumb. 
     In some configurations, the firearm may include a pistol grip and a void or compartment may be disposed in or above the rear of the pistol grip with the trigger extending into the void. 
     In some configurations, the trigger body may include an arm having a catch for engaging a lip on a hammer of the trigger mechanism. 
     In some configurations, the trigger body may carry a disconnector which has a catch for engaging a lip on the hammer of the trigger mechanism. 
     In some configurations, the hammer may include an arm having a lip on one side for engaging a disconnector and a lip on the other side for engaging a catch on the trigger body. 
     These and other aspects of the present invention are realized in the trigger mechanism for firearms which can be actuated by the user&#39;s thumb. The trigger mechanism may provide increased safety and potentially increased accuracy while firing the weapon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments of the present disclosure are shown and described in reference to the numbered drawings wherein: 
         FIGS. 1 through 3  illustrate a side view of the functioning of a trigger mechanism of a conventional semi-automatic rifle; 
         FIG. 4  shows a side view of the functioning of a trigger mechanism of an automatic rifle. 
         FIG. 5  shows a side view of a trigger mechanism made in accordance with principles of the present invention in a state ready for firing; 
         FIG. 6  shows a side view of the trigger mechanism of  FIG. 5  in an open, firing position; 
         FIG. 7  shows a side view of the trigger mechanism in a return position after firing, but before being ready for firing; 
         FIG. 8  shows a side view of a lower receiver having a trigger mechanism in accordance with the present invention disposed in a firing position; 
         FIG. 9  shows a rear perspective view of an alternate configuration of the lower receiver and pistol grip. 
         FIG. 10  shows a side view of the trigger mechanism in a reset position after firing; 
         FIG. 11  shows a rear perspective view of the side view of the lower receiver with the trigger in a ready-to-fire position; 
         FIG. 12  shows an exploded view of a thumb operated receiver; and 
         FIG. 13  shows a side view of the thumb operated receiver of  FIG. 12 . 
     
    
    
     It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The embodiments shown accomplish various aspects and objects of the invention. It will be appreciated that it is not possible to clearly show each element and aspect of the present disclosure in a single figure, and as such, multiple figures are presented to separately illustrate the various details of different aspects of the invention in greater clarity. Similarly, not all configurations or embodiments described herein or covered by the appended claims will include all the aspects of the present disclosure as discussed above. 
     DETAILED DESCRIPTION 
     Various aspects of the invention and accompanying drawings will now be discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The skilled artisan will understand, however, that the methods described below can be practiced without employing these specific details, or that they can be used for purposes other than those described herein. Indeed, they can be modified and can be used in conjunction with products and techniques known to those of skill in the art in light of the present disclosure. The drawings and the descriptions thereof are intended to be exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims. Furthermore, it will be appreciated that the drawings may show aspects of the invention in isolation and the elements in one figure may be used in conjunction with elements shown in other figures. 
     Reference in the specification to “one embodiment,” “one configuration,” “an embodiment,” or “a configuration” means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment, etc. The appearances of the phrase “in one embodiment” in various places may not necessarily limit the inclusion of a particular element of the invention to a single embodiment, rather the element may be included in other or all embodiments discussed herein. 
     Furthermore, the described features, structures, or characteristics of embodiments of the present disclosure may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details may be provided, such as examples of products or manufacturing techniques that may be used, to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that embodiments discussed in the disclosure may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations may not be shown or described in detail to avoid obscuring aspects of the invention. 
     Before the present invention is disclosed and described in detail, it should be understood that the present invention is not limited to any particular structures, process steps, or materials discussed or disclosed herein, but is extended to include equivalents thereof as would be recognized by those of ordinary skill in the relevant art. More specifically, the invention is defined by the terms set forth in the claims. It should also be understood that terminology contained herein is used for the purpose of describing particular aspects of the invention only and is not intended to limit the invention to the aspects or embodiments shown unless expressly indicated as such. Likewise, the discussion of any particular aspect of the invention is not to be understood as a requirement that such aspect is required to be present apart from an express inclusion of that aspect in the claims. 
     It should also be noted that, as used in this specification and the appended claims, singular forms such as “a,” “an,” and “the” may include the plural unless the context clearly dictates otherwise. Thus, for example, reference to “a bracket” may include an embodiment having one or more of such brackets, and reference to “the target plate” may include reference to one or more of such target plates. 
     As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result to function as indicated. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context, such that enclosing the nearly all of the length of a lumen would be substantially enclosed, even if the distal end of the structure enclosing the lumen had a slit or channel formed along a portion thereof. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. For example, structure which is “substantially free of” a bottom would either completely lack a bottom or so nearly completely lack a bottom that the effect would be effectively the same as if it completely lacked a bottom. 
     As used herein, the term “generally” refers to something that has characteristics of a quality without being exactly that quality. For example, a structure said to be generally vertical would be at least as vertical as horizontal, i.e. would extend 45 degrees or greater from horizontal. Likewise, something said to be generally circular may be rounded like an oval but need not have a consistent diameter in every direction. 
     As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint while still accomplishing the function associated with the range. 
     As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. 
     Concentrations, amounts, proportions and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually. This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described. 
     Turning now to  FIG. 1 , there is shown a side view of the trigger mechanism, generally indicated at 4, of a conventional semi-automatic rifle, such as an AR-15. The trigger mechanism  4  may include a trigger body  8 , including a trigger  8   a , a front face  8   b  and a rear arm or portion  8   c . Disposed adjacent the rear arm  8   c  is a safety  10 . The trigger body  8  pivots about a pin  12  and engages a trigger spring  22  so that trigger  8   a  is biased in a forward position. 
     Carried partly in the trigger body  8  is a disconnector  14 . Disposed toward the front face  8   b  of the trigger body  8  is a hammer  18 . The hammer  18  pivots about a pin  20  and is biased into an open or firing position by a hammer spring  26 . As will be discussed below, the trigger body  8  and the disconnector  14  selectively hold the hammer  18  in various positions during the firing cycle of the weapon. 
     In order to use the weapon, the safety  10  is rotated into a fire ready position as shown in  FIG. 1 . When not in use, the safety  10  is rotated 90° so that the safety body engages the trigger body  8  and prevents the trigger  8   a  from pivoting rearwardly when force is applied thereto. Rotating the safety  10  into the fire position aligns a channel in the safety body with the rear arm  8   c  of the trigger body to thereby enable the trigger body  8  to rotate as the trigger  8   a  is pulled. 
     The initial position of the trigger  8  causes a front face  8   b  of the trigger body to engage a sear  18   a  on the hammer  18  to hold the hammer in place. Pulling on the trigger  8  causes the trigger body to rotate with the rear arm  8   b  of the trigger body so that the rear arm moves into a void in the safety, and the front face  8   b  to pivot downwardly out of engagement with the sear  18   a . This allows the hammer  18  to pivot upwardly and forwardly under the force of the hammer spring  26  and forcefully strike the bolt action assembly  30  to cause the firing pin (not shown) to engage the bullet and cause discharge as shown in  FIG. 2 . 
     The force of the powder charge in the cartridge behind bullet exploding drives the bolt action assembly  30  rearwardly, pushing the hammer  18  down into the position shown in  FIG. 3 . The hammer  18  includes a lip  18   b  and the disconnector  14  includes a catch  14   a  which engages the lip to form retaining members when the bolt action assembly  30  pushes the hammer  18  downwardly/rearwardly in  FIG. 3 . The catch  14   a  momentarily holds the hammer  18  in place while the trigger body  8  rotates back into a position where the front face  8   b  will engage the sear  18   a  on the hammer. As the trigger  8   a  rotates back into place, the catch  14   a  disengages from the lip  18   b  so as to return the hammer  18  into the position shown in  FIG. 1 . 
     In a fully automatic version, shown in  FIG. 4 , a second disconnector  32  is disposed above and rearwardly from disconnector  14  and is mounted on a pin  34  which allows the second disconnector to pivot. A spring  35  is used to bias the second disconnector  32  into a downward slope ending in an engagement face  36 . The hammer  18  also includes a projection  38  extending from a top end thereof. When the trigger  8   c  is pulled and held down, the rearward thrust of the bolt action assembly  30  pushes the hammer rearwardly until the projection  38  passes the engagement face  36 , at which point the second disconnector will hold the hammer  18  in the orientation shown in  FIG. 4 . 
     As the bolt action assembly slides forwardly back into position for firing the next round, the bolt action assembly engages the second disconnector  32  and causes the second disconnector to pivot, thereby releasing the hammer  18  from the second disconnector. Once released, the hammer spring  26  drives the hammer  18  back into contact with the bolt action assembly (e.g., the firing pin) to thereby fire the bullet. As long as the trigger  8   a  is held back, the hammer  18  will continue to reengage with and then be released from the second disconnector  32  as the bolt action assembly slides back and forth, thereby firing bullets until either the trigger is released—thereby causing face  8   b  to engage with the sear  18   a , or until all of the cartridges have been fired. 
     Turning now to  FIG. 5 , there is shown a trigger mechanism generally indicated at  44 , made in accordance with the principles of the present invention. The trigger mechanism includes a trigger body  48  which pivots about a trigger pin  52 . The trigger body  48  may include a first trigger portion or trigger arm which forms a trigger  48   a , a second trigger portion or second trigger arm which includes a retention member, such as a trigger catch  48   b , and a third trigger portion or third trigger arm which forms a safety structure  48   c  (which may be a slot or projection as shown below). The safety structure  48   c  may engage a safety  50  to selectively prevent pivoting of the trigger body  48  about the trigger pin  52 . As shown in  FIG. 5 , the first trigger arm forming the trigger is disposed on one side of the trigger pin  52 , while the second trigger arm and third trigger arm are disposed on an opposing side of the trigger pin. 
     Disposed partially in the trigger body  48  is a disconnector  54 . The disconnector  54  may include a retention member, such as a disconnector catch  54   a  which may be configured to engage a first hammer retention member, such as a hammer lip or hammer catch  58   b  on a hammer  58 . The hammer  58  may also include a second hammer retention member, such as a second hammer lip or second hammer catch  58   a  which can be engaged by the trigger catch  48   b  on the trigger body  48 . The first hammer lip  58   b  and the second hammer lip  58   a  can be disposed on a hammer arm  58   c  extending from the main body of the hammer  18 . 
     As shown in  FIG. 5 , the trigger mechanism  44  is prepared for firing. By pressing downwardly on the trigger  48   a  as shown in  FIG. 6 , the trigger body  48  rotates about trigger pin  52  (downwardly on the left side and upwardly on the right) and causes the trigger catch  48   b  to release the second hammer lip  58   a  of the hammer  58 . This allows the hammer spring  66  to rotate the hammer  58  about the hammer pin  60  so that the hammer moves forwardly and upwardly to strike the bolt action assembly (not shown) to engage the primer or rim of a cartridge, thereby causing the firing of a bullet. 
     As the bolt action assembly moves rearwardly in response to the explosive force in the cartridge, the bolt action assembly engages the hammer  58  and pushes the hammer rearwardly and downwardly until the first hammer lip  58   b  engages the disconnector catch  54   a  on the disconnector  54  as shown in  FIG. 7 . The disconnector  54  momentarily holds the hammer  58  by the first hammer lip  58   b  while the trigger body  48  is returning to its normal or rest position. As the trigger catch  48   b  moves forward to reengage the second hammer lip  58   a  on hammer arm  58   c , the disconnector catch  54   a  is released from the first lip  58   b  on the hammer  58 , returning the trigger mechanism  44  to the orientation shown in  FIG. 5 . 
     The length of the arm forming the trigger  48   a  can be adjusted to accommodate the receiver in which the trigger mechanism  44  is disposed. In such a configuration a user may fire rounds by pressing on the trigger with their thumb. This enables a person to fire rounds without having to use their index finger. This can be advantageous, for example, if it is very cold and the person is or wearing a glove on their hand. Likewise, it allows the trigger  48  to be positioned so that it is less likely to be interfered with by branches in forests, etc. 
     It will be appreciated that this configuration may also be used for a fully automatic weapon. For example, the hammer  58  may include a projection  70 , and a second disconnector  74  could be provided to maintain firing as long as the bolt action assembly continues to reset the engagement between the projection  70  on the hammer and the second disconnector. 
     Turning now to  FIG. 8 , there is shown a side view of the lower receiver  80  with the trigger  48  in a ready-to-fire position. The lower receiver  80  includes a first hole  52   a  for receiving the trigger pin  52  ( FIGS. 5-7 ) about which the trigger body  48  pivots. The lower receiver also includes a second hole  60   a  for receiving the hammer pin  60  ( FIGS. 5-7 ) about which the hammer  58  pivots. Also shown on the lower receiver  80  is the safety switch  50 . The safety switch may include a plurality of raised surfaces  84  which may be used to slide the safety switch between an initial, safety position (shown in  FIG. 8 ), and an open, fire position caused by moving the safety switch forward. Preferably, the safety switch is constructed so as to give an audible click when the switch is moved between the safety and fire positions so that the shooter knows that the gun is ready to fire. It will be appreciated that the placement of the safety switch allows the user to move it between safety and fire positions with their index finger, thereby allowing the user to keep their hand on the pistol grip  78 . 
     The lower receiver  80  may also include other structures similar to conventional lower receivers. For example, the lower receiver  80  includes a hole  82  for mounting the bolt catch (not shown), a hole  88  for receiving the pivot pin for attachment to the upper receiver, and the mount  92  for attachment of the butt stock assembly (not shown). The lower receiver  80  also includes a magazine compartment  96  for receiving a magazine  98  of bullets. 
     Toward the back of the receiver is a void or chamber  99  which extends inwardly. The trigger  48   a  forms a lever disposed in the void so that the shooter can fire the weapon by pressing on the lever with his or her thumb. While shown in  FIG. 8  as being above the pistol grip  78 , it will be appreciated that the arm or lever forming the trigger  48 ′ could be at a different angle and length so that it extends down into a void or chamber  99 ′ in the rear of the pistol grip. 
       FIG. 9  shows an alternate configuration of the lower receiver  80  and the pistol grip  78 . The void or chamber  99 ″ has closed sidewalls  100  to further protect a trigger (not shown) disposed inside. 
       FIG. 10  shows a side view of an alternate configuration of the trigger mechanism, generally indicated at  104 . The trigger mechanism  104  includes the trigger body  108  which includes a first arm or lever forming the trigger  108   a  and extending downwardly at an angle. The trigger body  108  further includes a second arm which may extend generally vertically (i.e., about 110-130 degrees from the first arm) along which the catch  108   b  is disposed. A third arm extends forwardly (i.e., about 140-170 degrees from the first arm) on a side opposite the hole  112   a  into which the trigger body pin is disposed. The third arm receives the disconnector  114  and has a safety structure  108   c  in the form of a projection  113  disposed along the arm. The safety  110  includes an arm  115  which selectively engages the projection for engaging the projection  113  such that when the arm engages the projection, the trigger body  108  cannot pivot upwardly with the third arm or downwardly with the first arm forming the trigger  108   a . The safety  110  may also include a detent pin (i.e., a pin which nests in an indentation in the lower receiver) so as to provide an auditory indication when the safety is been moved into the fire position. 
     The disconnector  114  rides on/in the third arm, such that pressing downwardly on the trigger  108   a  moves the third arm and the disconnector upwardly. This facilitates the engagement of the engagement members (catch  114   a  disposed on the arm  114   b  and lip  118   b  on the arm  118   c  of the hammer  118 ) momentarily engaging while the other engagement members reengage. In other words, trigger  108  body pivots back into its original position, where the catch  108   b  engages and holds the second lip  118   a  on the arm  118   c  of the hammer  18 . It will be appreciated that the relative orientations of the portions or arms of the trigger body  108  can be adjusted to change the position of the trigger  108   a  depending on its desired position. 
     Turning now to  FIG. 11 , there is shown a rear perspective view of the trigger mechanism  104 . The manner in which the projection  113  on the third arm or portion of the trigger body  108  is received into a notch  117  in the arm  115  of the safety  110  can clearly be seen. Moving the safety  110  forward, such as pushing forward on the raised surfaces  74  moves the projection  113  out of the notch (or the arm from around the projection to be more specific) and allows the trigger body  108  to pivot. 
     The position of the trigger body  108 , the disconnector  114  and the hammer  118  shown in  FIG. 11  is consistent with the position of those structures immediately after the bolt action assembly (not show) has moved rearwardly to return the hammer  118 , but prior to rotation of the trigger  108   a  upwardly enough that the engagement member or catch  114   a  on the disconnector releases the engagement member or first lip  118   b  on the arm  118   c  of the hammer and the engagement member or catch  108   b  on the trigger body reengages the engagement member or second lip  118   a  on the hammer body. It will be appreciated that cycling from the initial pre-firing orientation, to the firing position (where the hammer strikes the bolt action assembly), into the orientation shown in  FIG. 11  and back into the original pre-firing position takes a mere fraction of a second. 
     Also shown in  FIG. 11  are the shoulders  112   b  and  120   b  which surround the holes  112   a  and  120   a  which hold the pins for the trigger body  108  and the hammer  118 , respectively. The shoulders are provided for mounting the trigger body spring and the hammer body spring discussed above. 
     Turning now to  FIG. 12 , there is shown an exploded view of a lower receiver  180  and trigger mechanism  144 . At the top of the figure is the hammer  158  just above a hammer spring  166  which biases the hammer into a firing position. Below the hammer spring  166  is the disconnector  154  which can be positioned in the slot of the trigger body  148 . To the left of the trigger body are the buffer retainer  151  and the buffer retainer spring  153 . 
     To the right and down from the trigger body  48  is a bolt catch roller pin  157  and a bolt catch  159 . Below the bolt catch  159  is the bolt catch plunger  161  and the bolt catch spring  163 . Further to the right are the magazine catch  165  and the magazine catch spring  167 . A safety selector  171  and safety screw  173  can be positioned on one side of the receiver  180 , while a second safety selector  171   a  and second safety screw  173   a  can be positioned on the other side so that the safety may be actuated on either side of the receiver. Positioned below the trigger body  148  is the trigger spring  162  and the safety  150  which is engaged by the safety selector  171  to selectively engage the projection on the trigger body  148 . 
     Disposed to the left of the lower receiver  180  is the take down pin spring  175  and the take down pin detent  177 , while the take down  179  pin is disposed just under the left end of the lower receiver  180 . Just below the take down pin spring  175  and the take down spring detent  177  is the gas shield  181  which may nest in the open top portion of the grip  178  and may include channel for the trigger to pass through. The grip  178  may be attached to the lower receiver  180  by a pair of grip screws  183 . 
     Disposed adjacent to the grip  178  are the trigger pin  152  and the hammer pin  160 . Adjacent the pins  152  and  160  are the magazine release button  185  and the safety selector spring  187 . Adjacent the safety selector spring  187  is the pivot pin  189 . Disposed at the right end of the lower receiver  180  are the pivot pin spring  191  and the pivot pin detent  193 . 
       FIG. 13  is a side view of the lower receiver  180  and the pistol grip  178 . In use, the shooter would insert their thumb into the void at the top of the pistol grip  178  (viewable in  FIG. 12 ) to push down on the trigger and fire the gun. 
     While discussed in the context of semiautomatic and automatic firearms, it will be appreciated that the trigger of a conventional firearm which is neither semiautomatic or automatic could be configured to use a trigger that includes a lever or arm which extends rearwardly so that it is disposed in or adjacent the rear of the handle of the weapon so that the lever can be engaged by the shooter&#39;s thumb, thereby firing the weapon. 
     Thus, there is disclosed a trigger mechanism for firearms. It will be appreciated that numerous modifications may be made without departing from the scope and spirit of this disclosure. The appended claims are intended to cover such modifications.