Patent Publication Number: US-2023136053-A1

Title: Firearm trigger assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 63/263,165 filed on Oct. 28, 2021, entitled “2-STAGE RIFLE TRIGGER ASSEMBLY,” which is hereby incorporated by reference in its entirety for all that is taught and disclosed therein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to firearms, and more particularly to a firearm trigger assembly that has two stages to provide feedback to the shooter without adversely affecting the trigger&#39;s reset time by increasing trigger travel to reset. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Rifle triggers are available in single-stage and two-stage forms. Single-stage triggers feature an unchanging pull weight throughout the entire trigger motion until the rifle discharges. In contrast, two-stage triggers typically feature a lower pull weight during the first stage&#39;s range of motion that terminates in a “wall” at the end of the first stage. This significant change in pull weight signals the shooter that additional trigger movement will discharge the firearm. 
     AR-15 rifles typically come with a mil-spec, single-stage trigger. This has the disadvantage of having a high pull weight relative to many alternative single-stage triggers. AR-15 mil-spec triggers also require a substantial range of trigger motion to discharge the rifle because of the extended length of the sear point on the hammer. Replacement AR-15 rifle single-stage triggers provide a high degree of responsiveness and reset speed for a follow-on shot, but they lack the feedback and increased safety provided by a two-stage trigger. Conventional replacement AR-15 rifle two-stage triggers have the disadvantage of having a longer reset time for a follow-on shot compared to single-stage triggers. An additional disadvantage of conventional 2-stage triggers is the requirement to use the disconnector spring for the second stage, which forces opposing benefits: having a clear, distinct wall, or having a fast, crisp trigger reset. This requirement also affects the pull weight. Thus, there are a lot of undesirable compromises associated with a conventional 2-stage trigger. 
     Therefore, a need exists for a new and improved firearm trigger assembly that has two stages to provide feedback to the shooter without adversely affecting the trigger&#39;s reset time by increasing trigger travel to reset. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the firearm trigger assembly according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of having two stages to provide feedback to the shooter without adversely affecting the trigger&#39;s reset time. 
     The present invention provides an improved firearm trigger assembly, and overcomes the above-mentioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide an improved firearm trigger assembly that has all the advantages of the prior art mentioned above. 
     To attain this, the preferred embodiment of the present invention essentially comprises a frame, a hammer pivotally connected to the frame, a trigger element pivotally connected to the frame and operable to selectively restrain and release the hammer in response to movement of the trigger element between a restraint position and a release position, a trigger lever movably connected to the trigger element and movable with respect to the trigger element between a first unactuated position and a second actuated position, the trigger element being configured to remain in the restraint position when the trigger lever is in the first unactuated position, in any of a range of positions intermediate the first unactuated position and the second actuated position, and when in the second actuated position with an application of force to the trigger lever below a selected force threshold, and the trigger lever being operable to move the trigger element to the release position in response to an application of force to the trigger lever greater than the selected force threshold. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached. 
     There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a left side view of the current embodiment of a firearm trigger assembly constructed in accordance with the principles of the present invention in use installed in a rifle. 
         FIG.  2    is a top isometric view of the firearm trigger assembly of  FIG.  1    detached from the rifle. 
         FIG.  3    is an exploded view of the firearm trigger assembly of  FIG.  1    detached from the rifle. 
         FIG.  4    is a side sectional view of the firearm trigger assembly of  FIG.  1   . 
         FIG.  5    is a top sectional view of the firearm trigger assembly of  FIG.  1   . 
         FIG.  6 A  is a side sectional view of the firearm trigger assembly of  FIG.  1    in the first unactuated position. 
         FIG.  6 B  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in one of a range of positions intermediate the first unactuated position and the second actuated position. 
         FIG.  6 C  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in the second actuated position with an application of force to the trigger lever below a selected force threshold. 
         FIG.  6 D  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in the second actuated position with an application of force to the trigger lever greater than the selected force threshold such that the sear has released the hammer. 
         FIG.  6 E  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in the second actuated position with an application of force to the trigger lever greater than the selected force threshold. The hammer has recoiled under the influence of the rifle action and has been caught by the disconnector. 
         FIG.  7 A  is a side sectional view of the firearm trigger assembly of  FIG.  1    in the first unactuated position. 
         FIG.  7 B  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in one of a range of positions intermediate the first unactuated position and the second actuated position. 
         FIG.  7 C  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in another one of a range of positions intermediate the first unactuated position and the second actuated position. 
         FIG.  7 D  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in the second actuated position with an application of force to the trigger lever below a selected force threshold. 
         FIG.  7 E  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in the second actuated position with an application of force to the trigger lever greater than the selected force threshold such that the sear has released the hammer. 
         FIG.  7 F  is a side sectional view of the firearm trigger assembly of  FIG.  1    showing the trigger lever in the second actuated position with an application of force to the trigger lever greater than the selected force threshold. The hammer has recoiled under the influence of the rifle action and has been caught by the disconnector. 
     
    
    
     The same reference numerals refer to the same parts throughout the various figures. 
     DESCRIPTION OF THE CURRENT EMBODIMENT 
     An embodiment of the firearm trigger assembly of the present invention is shown and generally designated by the reference numeral  10 . 
       FIGS.  1 - 5    illustrate the improved firearm trigger assembly  10  of the present invention. More particularly,  FIG.  1    shows the firearm trigger assembly in use installed in a rifle  12  shown in dashed lines. In the current embodiment, the rifle is an AR-15 rifle. The firearm trigger assembly has a frame  14  with a hammer  16  pivotally connected to the frame and a trigger element  18  pivotally connected to the frame and operable to selectively restrain and release the hammer in response to movement of the trigger element between a restraint position and a release position. A trigger lever  20  is movably connected to the trigger element and is movable with respect to the trigger element between a first unactuated position and a second actuated position. The trigger element is configured to remain in the restraint position when the trigger lever is in the first unactuated position, in any of a range of positions intermediate the first unactuated position and the second actuated position, and when in the second actuated position with an application of force to the trigger lever below a selected force threshold. The trigger lever is also operable to move the trigger element to the release position in response to an application of force to the trigger lever greater than the selected force threshold. 
     In the current embodiment, the trigger lever  20  is biased to the first unactuated position, and the trigger element  18  has a lever portion  22  coextensive with the trigger lever. The lever portion of the trigger element extends adjacent to the trigger lever. The trigger lever has a free end  38  operable to contact a free end portion  36  of the lever portion of the trigger element to motivate the trigger element. Furthermore, the trigger element and trigger lever each have lever portions  22 ,  34  each having free ends  36 ,  38 , and the free ends of each lever portion abut each other when the trigger lever is in the second actuated position. 
     A disconnector  24  is connected to the trigger lever  20 . Both the trigger lever and the trigger element  18  pivot about a common axis  26 . The free ends  36 ,  38  of both the trigger lever and the trigger element extend a common distance from the common axis. A hammer spring  28  is connected to the trigger lever to establish a first stage pull weight. A trigger element spring  30  biases the trigger element with respect to the frame  14  to establish the selected force threshold. The majority of threshold force comes from sear friction and pushing the hammer  16  out of the way, but any adjustability is from the trigger element spring, which is a small spring positioned underneath the trigger element. The trigger lever is biased by a second spring (the hammer spring) other than the trigger element spring. Thus, a first spring (the trigger element spring) intervenes between the trigger element and the frame, and a second spring (the hammer spring) intervenes between the hammer and the trigger lever. 
     The firearm trigger assembly  10  is assembled into a single unit that can be readily installed into a host rifle  12  for easy assembly. The two-stage trigger functionality is divided into two separate movements to fully release the hammer  16  and fire the rifle. The trigger element  18  and trigger lever  20  operate independently of each other. Therefore, the first stage and second stage trigger movements are separate moving parts. The trigger lever is partially received by the trigger element in varying amounts as the trigger lever&#39;s position moves between the first unactuated position and the second actuated position. 
     To assemble the firearm trigger assembly  10 , a disconnector spring  40  is inserted into a spring hole  42  in the trigger lever  20  to bias the disconnector forward. The disconnector  24  is then slid onto the trigger lever, and a disconnector pin  44  secures the disconnector in place. The trigger lever is then interlocked into the trigger element  18  by rotating, sliding them together, rotating the opposite direction, and finally sliding the trigger element upwards to align the bushing holes  46 ,  48 . The trigger element includes a ring-shaped feature  50  that is raised above the main surface  52  by a small amount. The ring-shaped feature minimizes surface friction between the trigger lever and the trigger element, which allows for more force control during assembly and in use for shooting. An additional ring-shaped feature is present on the opposed side of the trigger element to minimize surface friction when interacting with a safety catch  54 . 
     Subsequently, a trigger link  56  (shown in  FIGS.  7 A-E ) is installed on the trigger lever  20  and is held in place rigidly by a socket cap screw  58 . Location  60  on the trigger lever interacts with location  62  on the trigger link to prevent the rifle  12  from firing when force is applied to either the trigger lever or trigger element  18  while the rifle&#39;s safety is on. The trigger element spring  30  is then inserted into a spring hole  64  in the trigger element. The trigger element spring is secured by a set screw  66 . The trigger element spring places tension on the trigger element. The force exerted by the trigger element spring is set independently of the tension of the trigger lever by adjusting the height of the set screw. 
     The safety catch  54  has an aperture  68  that aligns with the bushing holes  46 ,  48  of the trigger element  18  and trigger lever  20 . The alignment is maintained by a bushing  70  that will be installed later, which allows for rotation about the bushing. The rear  72  of the safety catch sits on a portion  74  of the disconnector pin  44 . When the trigger lever is pulled, the front  76  of the safety catch rotates downward. The safety catch serves as a drop safety and prevents any inadvertent striking of the firing pin if the hammer  16  were to ever disengage from the trigger sear  78  on the trigger element unintentionally. The safety catch stops the hammer in a position where, even if the hammer were to be released from that position, the hammer lacks sufficient energy to discharge the rifle  14 . The safety catch ensures the trigger lever and trigger element must be intentionally pulled for the rifle to fire. 
     The components that have been assembled thus far into a subassembly are subsequently placed in the frame  14 . A bushing  80  will be inserted into the bushing holes  82 ,  84  defined by the frame to hold the subassembly in place. Compression springs  32  are then installed into the bottom  86  of the frame. The compression springs make installation of the firearm trigger assembly  10  in the rifle  14  easy, consistent, and secure. The compression springs place upward tension on the bottom rear of the frame, which applies consistent force to the bushings and the trigger pins in the receiver of the rifle. The hammer  16  and hammer spring  28  are then installed in the frame. The hammer spring provides force for the hammer, the safety catch  54 , and the trigger lever  20 . A full-length spring leg  86  of the hammer spring rests on the safety catch, which keeps the rear  72  safety catch firmly pressed into the portion  74  of the disconnector pin  44 . The full-length spring leg also provides most of the pull weight of the trigger lever  20 . A shorter length spring leg  88  rests on the trigger link  56  and contributes minimally to the pull weight of the trigger lever because the shorter length spring leg terminates so close to the common axis  26 . Finally, the bushings  70 ,  80  are installed by inserting them in the various bushing holes in the components and frame. 
       FIGS.  6 A-E  and  7 A-E illustrate the improved firearm trigger assembly  10  of the present invention. More particularly,  FIGS.  6 A and  7 A  show the trigger lever  20  in the first unactuated position ready to fire.  FIGS.  6 B and  7 B  show the trigger lever partially pulled rearward in one of a range of positions intermediate the first unactuated position and the second actuated position. The trigger lever has not yet encountered the trigger element  18 , which has remained stationary.  FIG.  7 C  shows the trigger lever partially pulled rearward in another one of a range of positions intermediate the first unactuated position and the second actuated position. The trigger lever has not yet encountered the trigger element  18 , which has remained stationary. The trigger link  56  has begun to separate from contacting the trigger element.  FIGS.  6 C and  7 D  show the trigger lever bottomed out against the trigger element in the second actuated position with an application of force to the trigger lever below a selected force threshold. The first stage of trigger pull is complete, and the user experiences increased resistance indicating that increased force will be required to perform the second stage of trigger pull to discharge the rifle  14 . The contact between the trigger lever and trigger element also provides a visual indication the first stage of trigger pull is complete.  FIGS.  6 D and  7 E  show the trigger lever having moved the trigger element to the release position in response to an application of force to the trigger lever greater than the selected force threshold. The hammer has been released by the trigger sear to discharge the rifle.  FIGS.  6 E and  7 F  show the hammer has recoiled under the influence of the rifle action and has been caught by the disconnector  24 . Once the trigger lever and trigger element have been released by the shooter, the hammer retention function will be transitioned from the disconnector to the trigger sear as the trigger lever and trigger element returned to the first unactuated position illustrated in  FIGS.  6 A and  7 A . The current invention allows the trigger element to be in contact with the hammer prior to the hammer releasing from the disconnector, which is a unique feature. Furthermore, the trigger lever does not have to fully return to its start position before the hammer resets. This allows for faster follow up shots that traditional 2-stage triggers cannot achieve. 
     It should be appreciated that the trigger link  56  is critical to the proper function of the firearm trigger assembly  10 . The trigger link is mounted on the trigger lever  20  using two locating bosses on the trigger link and a corresponding slot and hole on the trigger lever and is secured by the socket cap screw  58 . Once the trigger link is rigidly mounted on the trigger lever, an extended ledge  90  on the trigger link interfaces with a shelf  92  on the trigger element  18  and prohibits the trigger element from moving without the trigger lever (and by connection the trigger link) moving first. Therefore, with the safety catch  54  on safe, a back safety flat  94  on the trigger lever will not be able to move up, so neither the trigger lever nor the trigger element can be pulled without first disengaging the safety catch. Once the safety catch is off, the trigger lever can be pulled and will move the ledge on the trigger link completely out of the way of the shelf on the trigger element, allowing the trigger sear  78  to move downward and release the hammer  16 . 
     In the context of the specification, the terms “rear” and “rearward,” and “front” and “forward,” have the following definitions: “rear” or “rearward” means in the direction away from the muzzle of the firearm while “front” or “forward” means it is in the direction towards the muzzle of the firearm. 
     While a current embodiment of a firearm trigger assembly has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. Although rifles have been disclosed, the firearm trigger assembly is also suitable for use with any other firearm type where a two-stage trigger would be beneficial. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
     Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.