Patent Publication Number: US-10317165-B2

Title: Modular chassis/stock system for a firearm

Description:
FIELD OF THE INVENTION 
     The present disclosure is directed generally to firearms and, more particularly, to a modular chassis/stock system for a rifle type of firearm that incorporates a recoil reduction assembly. 
     BACKGROUND 
     The firing of a firearm typically results in a recoil caused by the force of the expanding gas propelling a bullet/shot down the barrel. The expanding gases force the firearm rearwardly in a recoil action. Accordingly, most rifle or long gun type firearms subject to substantial recoil include a buttstock for engaging the shooter&#39;s shoulder when firing the firearm to help support the firearm during a recoil action. 
     Recoil reduction devices have been employed with firearms to reduce recoil that is felt by the shooter when the firearm is fired. Reduction in recoil that is felt by the shooter reduces the fatigue of the shooter and also lessens the impacts on the shooter&#39;s body. In addition, the shooter is better able to maintain a sight picture to assist in shot identification, to assist in making follow-up shots, and to improve overall shooting performance. 
     The ability to easily configure a recoil reducing firearm to fit the shooter&#39;s needs and anatomy can be useful in several situations, such as in tactical, sniping and target shooting applications. In addition, a buttstock that supports the firearm is desirable where the overall weight of the firearm is minimized while incorporating a recoil reduction system. Accordingly, there remains a need for further improvements in this area. 
     SUMMARY 
     The present disclosure generally is related to a modular chassis/stock system for a rifle type firearm that incorporates a recoil reduction assembly. The chassis/stock system includes a buttstock assembly that is configured to include an elongated housing for receiving a mounting body of the recoil reduction assembly. The mounting body houses a recoil strut to which the recoil pad assembly is engaged. 
     In one embodiment, an adjustment member is threadingly engaged to the mounting body to adjust the length of pull between the recoil reduction assembly and the buttstock assembly. In another embodiment, a shroud is provided around the rearward end of the buttstock that surrounds the recoil pad assembly and recoil strut. 
     This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevation view of a modular chassis/stock system for a firearm including a lower receiver structure, a handguard/accessory rail, and a buttstock assembly that incorporates a recoil reduction assembly. 
         FIG. 2  is a left end elevation view of the part of the modular chassis/stock system of  FIG. 1 . 
         FIG. 3  is a longitudinal section view along line  3 - 3  of  FIG. 2 . 
         FIG. 4  is an enlarged elevation view of recoil reduction assembly and buttstock assembly of the modular stock system of  FIG. 1 . 
         FIG. 5  is an isometric, exploded view of part of the recoil reduction assembly and the buttstock assembly of  FIG. 4 . 
         FIG. 6A  is an elevation view a mounting body of the recoil reduction assembly. 
         FIGS. 6B and 6C  are end elevation views of the mounting body of  FIG. 6A . 
         FIG. 7  is an enlarged elevation view of another embodiment of a recoil reduction assembly and buttstock assembly for a modular stock system. 
         FIG. 8  is an isometric, exploded view of part of the recoil reduction assembly and the buttstock assembly of  FIG. 7 . 
         FIG. 9  is a longitudinal section view of a modular chassis/stock system for a firearm including a lower receiver structure, a handguard/accessory rail, and a buttstock assembly that incorporates the recoil reduction assembly and buttstock assembly of  FIG. 7 . 
     
    
    
     Those skilled in the art will appreciate and understand that, according to common practice, the various features of the drawings discussed below are not necessarily drawn to scale, and that dimensions of various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present invention described herein. 
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Referring now to the drawings in which like numerals indicate like parts throughout the several views, the figures illustrate example embodiments of the modular chassis/stock system  10  according to the principles of the present disclosure. Modular chassis/stock system  10  and/or one or more components thereof can be used for various types of firearms, including M4, M16, AR-15, SCAR, AK-47, HK416, ACR, sniper rifles, shotguns, hunting rifles and other long guns, and gas-operated semi-automatic, automatic and manually operable firearms. However, the present disclosure should not be limited to the listed examples. 
     The following description is provided as an enabling teaching of exemplary embodiments, and those skilled in the relevant art will recognize that many changes can be made to the embodiments described. It also will be apparent that some of the desired benefits of the embodiments described can be obtained by selecting some of the features of the embodiments without utilizing other features. Accordingly, those skilled in the art will recognize that many modifications and adaptations to the embodiments described are possible and may even be desirable in certain circumstances, and are a part of the invention. Thus, the following description is provided as illustrative of the principles of the embodiments and not in limitation thereof. 
     As shown in  FIGS. 1-3 , the chassis/stock system  10  generally includes a chassis  12  including a lower receiver  14  and a handguard/rail assembly  16  extending forwardly from lower receiver  14  to a forward end  22  of chassis  12 . Typical components that can be provided with or attached to chassis/stock system  10  not shown include an upper receiver mountable to the lower receiver  14  that includes firing control components such as sears and a trigger, a barrel assembly mountable to the upper receiver in handguard/rail assembly  16 , a bolt assembly slidably received in the upper receiver for operation of the chassis/stock system  10 , and a magazine that is positionable in magazine well  18  that is defined in the chassis  12  and in communication with the chamber for supplying ammunition to the chamber. Chassis  12  includes a pistol-style handgrip  20  adjacent a rearward end  24  of the chassis  12 . 
     In the illustrated embodiment, chassis/stock system  10  includes a buttstock assembly  30  that is mounted to the rearward end  24  of the chassis  12  at a hinge  32 .  FIG. 1  shows the chassis/stock system  10  in a shooting configuration with the buttstock assembly  30  in an extended position in alignment with the chassis  12 , with its hinge blocked or the buttstock assembly  30  otherwise fixed against further pivoting movement. The buttstock assembly  30  can also be moved to a folded position, pivoted forwardly toward the receiver  14 . 
     Referring further to  FIGS. 4 and 5 , buttstock assembly  30  includes a skeletonized body or frame  34  extending from a forward end  36  at hinge  32  and an opposite rearward end  38 . As used herein, forward and forwardly refer to the direction the chassis/stock system  10  is pointing when the firearm is being aimed at a target, and rearward and rearwardly refer to the opposite direction toward the shooter. As further shown in  FIG. 4 , the frame  34  of buttstock assembly  30  has a reduced mass and/or surface area as compared to a solid frame, and frame  34  includes a plurality of members that define one or more laterally opening windows. 
     In the illustrated embodiment, there is shown a first laterally opening window  40  and a second laterally opening window  42  defined by frame  34 . Frame  34  is sized and configured to provide the required structural support to transfer the force of the recoil to the recoil reduction assembly  80  (described below) without compromising the structural integrity of the buttstock assembly  30 . Frame  34  can be made from a light-weight, high strength material such as, for example, aluminum, magnesium, steel, other metals and metal alloys, polymers, carbon fiber, composites, or any other suitable material. The members forming frame  34  can be solid, hollow, or combinations thereof. 
     Frame  34  includes an elongated housing  60  for receiving a part of recoil reduction assembly  80  to allow recoil reduction assembly  80  to be mounted to buttstock assembly  30 . Housing  60  includes an outwardly projecting body portion  62  that extends outwardly from opposite sides of frame  34 . Body portion  62  extends from a forward end  64  to an opposite rearward end  66 . An inner bore  68  is defined by body portion  62  and opens at rearward end  66 . Inner bore  68  receives a part of recoil reduction assembly  80  therein. As discussed further below, in one embodiment, the recoil reduction assembly  80  is translatable into and out of inner bore  68  to adjust the length of pull. 
     Frame  34  includes an upper frame member  44  extending rearwardly from forward end  36  to a rear mounting pad  46  at rearward end  38 . Frame  34  also includes a lower frame member  48  extending forwardly from rear mounting pad  46  in parallel relation to upper frame member  44 . Frame  34  also includes an obliquely oriented forward frame member  50  extending between the upper and lower frame members  44 ,  48 . Frame  34  further includes an intermediate frame member  52  extending parallel to the upper and lower frame members  44 ,  48  that extends from the rear mounting pad  46  to the forward frame member  50 . 
     Frame  34  defines two windows  40 ,  42  in the illustrated embodiment. However, other embodiments contemplate no windows, one window, or three or more windows. In the illustrated embodiment, the first window  40  is defined by the rear mounting pad  46 , the lower frame member  48 , the forward frame member  50 , and the intermediate frame member  52 . The second window  42  is defined by forward end  64  of the elongated housing  60 , the intermediate frame member  52 , the forward frame member  50 , and the upper frame member  44 . Windows  40 ,  42  open at each of the lateral sides of frame  34 . 
     The elongated housing  60  is located between and extends along the upper frame member  44  and the intermediate frame member  52 . In one embodiment, the elongated housing  60  is formed unitarily with the upper frame member  44  and the intermediate frame member  52 . In another embodiment, the housing  60  is attached to one or more members of the frame  34 . 
     Frame  34  further defines a slot  70  between the forward end  64  of the elongated housing  60  and the rear mounting pad  46 . Buttstock assembly  30  also includes an adjustment member  72  that is received in the slot  70 . In the illustrated embodiment, adjustment member  72  is a thumbwheel that is positioned around a part of recoil reduction assembly  80  in slot  70  and rotated clockwise or counterclockwise by the shooter to adjust the length of pull. In another embodiment, the adjustment member  72  is a lever or tab that is pivoted or translated by the shooter to adjust the length of pull. 
     Recoil reduction assembly  80  includes a cylindrical mounting body  82  that is received in inner bore  68  of housing  60 . Mounting body  82  is shown in further details in  FIGS. 6A-6C . In one embodiment, the mounting body  82  includes threads  84  on an outer surface  86  of mounting body  82 . The adjustment member  72  is positioned around and threadingly engaged with threads  84  of mounting body  82  when mounting body  82  is positioned in inner bore  68  of housing  60 . The rearward end of mounting body can include a plurality of radially positioned, axially extending holes  87  and an internal hex shaped recess  89  for engagement of retention member  94 , which allows for adjustment of the tension of recoil reduction assembly  80 . 
     Recoil reduction assembly  80  further includes a recoil strut  90  that is positioned in a chamber  88  defined by mounting body  82 . Recoil strut  90  extends rearwardly though rear mounting pad  46  to a recoil pad assembly  92 . Recoil strut  90  can be employed in conjunction with a shock absorbing element in chamber  88  of mounting body  82 , such as a spring, gas cylinder, air cylinder, or other recoil absorbing device (not shown). The retention member  94  can be loosened or tightened on mounting body  82  to adjust the tension of recoil reduction assembly  80 . 
     Recoil reduction assembly  80  also includes an adjustable retention member  94  that is engaged to a rearward end of mounting body  82  to capture recoil strut  90  in chamber  88  mounting body  82  for engagement to rear mounting pad  46 . Tightening or loosening of adjustable retention member  94  adjusts the tension pressure of recoil strut  90 , providing for a stiffer or softer buffer depending on the adjustment that is made. In one embodiment, retention member  94  is a nut that extends through rear mounting pad  46  is rotated around recoil strut  90  to adjust the recoil resistance, but other arrangements are also contemplated. There is further provided a guide rod  96  that extends between rear mounting pad  46  and recoil pad assembly  92  to prevent or resist rotation of recoil pad assembly  92 . Guide rod  96  is received in a bore  104  formed through rear mounting pad  46  and lower frame member  48  and in a hole in recoil pad assembly  92 . Guide rod  96  and bore  104  extend parallel to recoil strut  90 . 
     Recoil pad assembly  92  includes a recoil pad (not shown), a back plate  98 , and an adapter plate  100 . Back plate  98  attaches to the recoil pad and includes a track  102  that allows the recoil pad to be moved up or down to better fit the shooter. Adapter plate  100  attaches the back plate  98  and the recoil pad to recoil strut  90 . 
     Buttstock assembly  30  includes a cheek piece  110  and a riser  112  that is attached to cheek piece  110  and frame  34 . Riser  112  is positioned along and extends through upper frame member  44  at the forward end  64  of housing  60 . Riser  112  is secured to upper frame member  44  with a fastener  114  that allows the vertical positioning of cheek piece  110  relative to upper frame member  44  to be adjusted and secured in the adjusted position. Cheek piece  110  is elongated and forms a U-shaped body that is positioned above upper frame member  44 . 
     Referring now to  FIGS. 7-9  there is shown another embodiment modular chassis/stock system  10 ′ that includes an adjustable modular buttstock assembly  30 ′ that is similar to or the same as modular chassis/stock system  10  and adjustable modular buttstock assembly  30  except as otherwise discussed. Therefore, elements in  FIGS. 7-9  that are similar or the same as the elements in  FIGS. 1-6  are designated with the same reference numeral and are not re-described herein with respect to  FIGS. 7-9 . 
     Frame  34 ′ of buttstock assembly  30 ′ includes an elongated cylindrical housing  160  that is located between and extends along the upper frame member  44  and the intermediate frame member  52 . In one embodiment, the elongated housing  160  is formed unitarily with the upper frame member  44  and the intermediate frame member  52 . In another embodiment, the housing  160  is attached to one or more members of the frame  34 ′. In contrast to housing  60 , housing  160  does not include any slot or adjustment member, but includes an inner bore  168  defined by laterally outwardly projecting body portion  162  for receiving a part of a recoil reduction assembly  180  like housing  60 . Body portion  162  of housing  160  includes a width that projects laterally outwardly from the adjoining frame members  44 ,  52  and a forward end wall  169  at the forward end  164  of housing  160 . Forward end wall  169  extends between frame members  44 ,  52 . 
     Buttstock assembly  30 ′ includes recoil reduction assembly  180  that includes a cylindrical mounting body  182  that is received in the inner bore  168  of housing  160  as shown in  FIG. 9 . In one embodiment, the mounting body  182  includes a smooth or non-threaded outer surface  186 . Recoil reduction assembly  180  further includes recoil strut  90  that is positioned in a chamber  188  defined by mounting body  182 . Chamber  188  includes a rearward portion  188   a  and a forward portion  188   b  that is reduced in cross-sectional size relative to rearward portion  188   a.    
     Recoil strut  90  extends rearwardly through a back plate  148  and a rear mounting shroud  146  to a recoil pad assembly  192 . Mounting shroud  146  forms an elongated oval or racetrack shaped perimeter around an inner space  147 . In the illustrated embodiment, mounting shroud  146  is formed as a unit with back plate  148  at the outer perimeter edge of back plate  148 . Back plate  148  defines a hole  149  that aligns with inner bore  168  of housing  160  and also define fastener bores  151  for receiving fasteners to secure back plate  148  and mounting shroud  146  to a rearward end of frame  34 ′. 
     Recoil strut  90  can be employed in conjunction with a shock absorbing element in the chamber  188  of mounting body  182 , such as a spring, gas cylinder, air cylinder, or other recoil absorbing device  191  in forward portion  188   b . Recoil strut  190  includes a cavity  193  for receiving the shock absorbing device  191 . Recoil strut  190  includes a flange  191  that is positioned in rearward portion  188   a  of chamber  188  that is in contact with or near contact with the inner wall surface of mounting body  182  to guide the reciprocating movement of recoil strut  190  in chamber  188 . The retention member  194  is secured against a rearward end  189  of mounting body  182  by a back plate  148  that is mounted to the rearward end of frame  34 ′, capturing recoil strut  90  in mounting body  182  and capturing mounting body  182  in inner bore  168  of housing  160 . 
     Recoil pad assembly  192  includes a recoil pad  204 , an optional spacer  202 , and an adapter plate  200 . One or more spacers  202  of selected thickness can be mounted between adapter plate  200  and recoil pad  34  to adjust the length of pull. Adapter plate  200  includes an inner flange  201  that is received in mounting shroud  146 . Mounting shroud surrounds the connection to recoil strut  90  and protects the space between recoil pad assembly  192  and the rearward end of frame  34 ′. Adapter plate  200  attaches any spacers  202  and the recoil pad  204  to recoil strut  90 . 
     Frame  34 ′ also includes a cheek piece  110 ′ that is similar to cheek piece  110  discussed above. However, cheek piece  110 ′ includes first and second risers  112   a ,  112   b  that are attached to cheek piece  110 ′ and frame  34 ′. Forward riser  112   a  extends through upper frame member  44  and into oblique frame member  50 , and rearward riser  112   b  is positioned along and extends through upper frame member  44  at the forward end  164  of housing  160 . Risers  112   a ,  112   b  can be secured to upper frame member  44  to allow the vertical positioning of cheek piece  110 ′ relative to upper frame member  44  to be adjusted and secured in the adjusted position. Cheek piece  110 ′ is elongated and forms a U-shaped body that is positioned above upper frame member  44 . 
     From the above description it is apparent that that the construction of a firearm and/or modular chassis/stock system  10 ,  10 ′ with an adjustable modular buttstock assembly  30 ,  30 ′ according to the principles of the present disclosure provides a firearm with a lightweight yet highly configurable buttstock and recoil reduction assemblies while further providing for substantially quick and easy adjustment and reconfiguration of features of the buttstock and recoil reduction assemblies. 
     It is believed that the disclosure set forth herein encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the disclosure includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. Similarly, recitation of “a,” “a first” or “the” element, or the equivalent thereof, should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements, unless the context clearly indicates otherwise. As used herein, the terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. 
     While the present application illustrates various embodiments, and while these embodiments have been described in some detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative embodiments, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant&#39;s general inventive concept.