Patent Publication Number: US-9885538-B2

Title: Adjustable ergonomic grip for a weapon

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional continuation of and claims priority to U.S. patent application Ser. No. 14/984,290, filed Dec. 30, 2015, entitled “ADJUSTABLE ERGONOMIC GRIP FOR A WEAPON,” the disclosure of which is expressly incorporated by reference herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used and licensed by or for the United States Government for any governmental purpose without payment of any royalties thereon. This invention (Navy Case 200,415) is assigned to the United States Government and is available for licensing for commercial purposes. Licensing and technical inquiries may be directed to the Technology Transfer Office, Naval Surface Warfare Center Crane, email: Cran_CTO@navy.mil. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The invention relates to firearms, and more particularly, to a firearm grip adjustable to a plurality of angular positions. 
     Adjustable grips for firearms are known in the art. Conventional firearm grips typically have standard sizes with set grip angles. A desired grip angle is often determined by the shooter&#39;s ability to fire the firearm with the center of mass of the shooter&#39;s hand aligned with the shooter&#39;s forearm with little to no wrist movement. More particularly, the desired grip angle is typically determined by what best accommodates shooting in a traditional rifle stance or in a squared tactical stance. With a traditional rifle stance, the shooter&#39;s weak side shoulder faces an opponent. With a squared tactical stance, the shooter&#39;s shoulders and torso are facing the target. 
     In both instances, the buttstock of the rifle is either placed near the centerline of the body or high up on the chest with elbows down or tucked-in. This results in ulnar deviation of the wrist which may lead to wrist fatigue and injury. While adjustable grips are available in the prior art, none are known to effectively correct for ulnar deviation present in currently used shooting stances, nor are easily and quickly adjustable in the field. 
     Therefore, there remains a need in the art to provide a field adjustable handgrip for firearms that effectively accommodates different shooting stances. 
     According to an illustrative embodiment of the present disclosure a firearm includes a body with a barrel extending along a longitudinal barrel axis, and a handgrip extending along a grip axis downwardly from the longitudinal barrel axis. The handgrip includes an upper grip portion coupled to the body, and a lower grip portion operably coupled to the upper grip portion for angular adjustment along a pivot axis extending perpendicular to the longitudinal barrel axis and the grip axis. A locking device is configured to move between a locked position and an actuated position, the locking device in the locked position secures the lower grip portion in one of a plurality of different angular positions relative to the upper grip portion, and the locking device in the actuated position permits rotational movement of the lower grip portion relative to the upper grip portion. A push button is supported by the lower grip portion and configured to move the locking device from the locked position to the actuated position. 
     According to a further illustrative embodiment of the present disclosure, an adjustable handgrip for a firearm includes an upper grip portion, a lower grip portion, a button, a locking device, a spring, and a button. The upper grip portion attaches to the firearm and has a downwardly extending lobe with a first pivot opening. The lower grip portion has an upwardly extending lobe with a second pivot opening. The first pivot opening and the second pivot opening are coaxially aligned so that the lower grip portion is angularly adjustable along the pivot opening axis relative to the upper grip portion. The button is coaxially aligned with the pivot axis within the first and second pivot openings. The locking device is operably coupled to the lower grip portion and is configured to move between a first position and second position. The locking device in the first position secures the lower grip portion in one of a plurality of different angular positions relative to the upper grip portion. The locking device in the second position releases the lower grip portion for angular adjustment relative to the upper grip portion. The spring is configured to bias the locking device along the pivot axis toward the first position, and the button is operably coupled to the locking device. When the button is depressed, it biases the spring and moves the locking device along the pivot axis toward the second position. 
     According to another illustrative embodiment of the present disclosure, a method of assembling an adjustable grip for a firearm includes the steps of providing a firearm, and coupling an upper grip portion of an adjustable handgrip to the firearm. The method further includes the steps of providing a lower grip portion, where first and second outer lobes are supported by one of the upper grip portion or the lower grip portion, the first outer lobe including a first pivot opening and the second outer lobe including a second pivot opening, and a center lobe supported by the other of the lower grip portion or the upper grip portion, the center lobe including a third pivot opening. The method further includes the steps of inserting a spring within the second pivot opening of the second outer lobe, inserting a locking device between the first and second outer lobes to bias against the spring, inserting the center lobe intermediate the first and second outer lobes, aligning the third pivot opening with the first and second pivot openings, and inserting a button within the aligned first and third pivot openings. 
     According to another illustrative embodiment of the present disclosure, a method of operating an adjustable handgrip for a firearm includes the steps of providing a firearm and an adjustable handgrip with an upper grip portion, a lower grip portion, and a button, and depressing the button to an actuated position, wherein a locking device releases the lower grip portion for rotational movement relative to the upper grip portion about a pivot axis. The method further includes the steps of rotating the lower grip portion of the adjustable grip relative to the upper grip portion about the pivot axis to a user desired angle of use, and releasing the button wherein the locking device is biased to a locked position to secure the lower grip portion at the user desired angle relative to the upper grip portion of the adjustable handgrip. 
     Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrative embodiment exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description when taken in conjunction with the accompanying drawings. 
         FIG. 1  is a side elevational view of an illustrative adjustable firearm grip coupled to a firearm; 
         FIG. 1A  is a detailed view of  FIG. 1 , showing the mounting of the illustrative adjustable firearm grip to the receiver body of the firearm; 
         FIG. 2  is a detailed side elevational view of  FIG. 1  showing the illustrative adjustable firearm grip positioned in a multitude of angular positions; 
         FIG. 3  is a first perspective view of the adjustable firearm grip of  FIG. 1 ; 
         FIG. 4  is second perspective view of the adjustable firearm grip of  FIG. 1 ; 
         FIG. 5  is a first exploded view of the adjustable firearm grip of  FIG. 1 ; 
         FIG. 6  is a second exploded view of the adjustable firearm grip of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view of the adjustable firearm grip taken along  7 - 7  of  FIG. 3 ; 
         FIG. 8  is a cross-sectional view of the adjustable firearm grip taken along line  8 - 8  of  FIG. 3 , showing the locking device in a static or locked position, with the push button biased in a first direction; 
         FIG. 9  is a cross-sectional view of the adjustable firearm grip taken along line  8 - 8  of  FIG. 3 , showing the locking device in an actuated or locked position, with the push button biased in a second direction; 
         FIG. 10  is a cross-sectional view similar to  FIG. 8  showing an alternative arrangement of the lower portion coupled to the upper portion; and 
         FIG. 11  is a cross-sectional view similar to  FIG. 8  showing an alternative means of retaining the button and locking device. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, which are described below. The embodiments disclosed below are not intended to be exhaustive or limit the invention to the precise form disclosed in the following description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings. It will be understood that no limitation of the scope of the invention is thereby intended. The invention includes any alterations and further modifications in the illustrated devices and described methods and further applications of the principles of the invention which would normally occur to one skilled in the art to which the invention relates. 
     Referring initially to  FIGS. 1 and 1A , an illustrative firearm  10  includes a receiver body  12 , a barrel  14  supported by the receiver body  12  and extending forwardly along a longitudinal barrel axis  16 , and a buttstock  18  extending rearwardly from the receiver body  12 . An ammunition cartridge  20 , a trigger  22 , and a handgrip  24  are supported by the receiver body  12 . The illustrative firearm  10  shown in the drawings is a long gun or rifle, such as an M16 rifle or an M4 carbine rifle. However, it should be appreciated that the present invention may be used with a wide variety of conventional firearms. 
     With reference to  FIGS. 2-4 , the handgrip  24  is attached to a portion of the receiver body  12  adjacent to the trigger  22 , and includes an upper grip portion  26  and a lower grip portion  28 . In an illustrative embodiment, the upper grip portion  26  is attached to the receiver body  12  by use of a conventional fastener, such as a machine screw  30 . More particularly, a lower receiver mounting tab  25  of the receiver body  12  is secured within a slot or channel  27  of the upper grip portion  26 . The channel  27  is defined by arms  29  and  31  of the upper grip portion  26 . 
     A safety selector detent  32  and safety selector detent spring  34  are illustratively received within a bore  36  extending between the receiver body  12  and the upper grip portion  26  proximate the machine screw  30 . The screw  30  extends through the channel  27  of the upper grip portion  26 , while the bore  36  extends within the arm  31  of the upper grip portion  26 . It should be appreciated that the detent spring  34  is captured within the bore  36  between the receiver body  12  and the upper grip portion  26 . As further detailed herein, the lower grip portion  28  may be adjusted without removing the upper grip portion  26 , which could result in the loss of the detent spring  34 . 
     With further reference to  FIGS. 2-4 , the lower grip portion  28  is coupled to the upper grip portion  26  along a pivot axis  38  and can be secured in a plurality of angular positions through operation of a user interface, such as a push button  40 . The lower grip portion  28  illustratively defines a grip axis  42  extending perpendicular to the pivot axis  38 . Illustratively, the grip axis  42  extends generally downwardly from the barrel axis  16 . As further detailed herein, depending upon the angular orientation of the lower grip portion  28 , the grip axis  42  may extend substantially perpendicular to the barrel axis  16 , substantially parallel to the barrel axis  16 , and in a variety of discrete positions therebetween. A cavity  43  may extend along the grip axis  42  and open downwardly within the lower grip portion  28  to provide a space for storage. 
     The lower grip portion  28  may be angularly adjusted about pivot axis  38  between a plurality of positions A, B, C and D from a forward position A (where grip axis  42  extends substantially vertical) rearwardly (clockwise in  FIG. 2 ) to a rearward position D. Illustratively, each position A, B, C, D is offset by approximately 15 degrees from each adjacent position A, B, C, D, such that the total range of angular adjustment from position A to position D is approximately 45 degrees. It should be appreciated that the number and degree of incremental angular adjustments, along with the total range of angular adjustment, may vary. For example, in one illustrative embodiment the lower grip portion  28  may be rotated rearwardly by 90 degrees from downward position A shown in  FIG. 2  to a rearward or stowed position, such that the grip axis  42  extends parallel to the barrel axis  16 , thereby providing a compact arrangement for carrying or concealing the firearm  10 . 
     With reference to  FIGS. 5 and 6 , the illustrative handgrip  24  includes a locking device  44  configured to secure the lower grip portion  28  in one of the plurality of different angular positions A, B, C, D relative to the upper grip portion  26 . The push button  40  is configured to release the locking device  44  in response to a user input, illustratively by depressing the push button  40 . In certain illustrative embodiments, indicia may be provided on the lower grip portion  28  in a dial type arrangement surrounding the push button  40 , wherein a mark on the push button  40  aligns with the indicia to provide the user with an indication of the selected angular orientation of the lower grip portion  28  relative to the upper grip portion  26 . 
     One illustrative embodiment of the locking device  44  is shown in  FIGS. 8 and 9 . The upper grip portion  26  has a downwardly extending center arm or lobe  46  with a first pivot opening  48 . The first pivot opening  48  of the downwardly extending center lobe  46  includes a counterbore  50  including a plurality of circumferentially spaced lugs or teeth  51 . The teeth  51  are illustratively arranged in a ring and are co-axially aligned with the first pivot opening  48  about pivot axis  38 . The lower grip portion  28  has an upwardly extending first outer arm or lobe  52  with a second pivot opening  54 , and an upwardly extending second outer arm or lobe  56  with a third pivot opening  58 . The first lobe  52  and the second lobe  56  of the lower grip portion  28  are in spaced relation to each other to define a center channel or slot  60  to receive the downwardly extending center lobe  46  of the upper grip portion  26 . As further detailed herein, the third pivot opening  58  of the upwardly extending second lobe  56  includes outer counterbore  67  and inner counterbore  69 . 
     The first pivot opening  48 , the second pivot opening  54 , and the third pivot opening  58  are coaxially aligned along the pivot axis  38 . A locking drum  62  is operably coupled to the lower grip portion  28 , and is configured to move axially along the pivot axis  38  between a first, static or locked position ( FIG. 8 ), and a second, actuated or released position ( FIG. 9 ). More particularly, the locking drum  62  includes a disc shaped body  64  having a first side supporting a protrusion or guide sleeve  66 , and a second side supporting a plurality of circumferentially spaced lugs or teeth  68 . 
     With reference to  FIGS. 5-7 , the protrusion  66  of the locking drum  62  is illustratively asymmetric, such as a non-concentric shaped wall. The non-concentric shaped protrusion  66  is axially aligned with the third pivot opening  58  of the lobe  56  of the lower grip portion  28 . Insertion of the non-concentric protrusion  66  into the inverse non-concentric shaped counterbore  67  of the lobe  56  prevents the rotation of the locking drum  62  relative to the lower grip portion  28 . The illustrative protrusion  66  is D-shaped and includes a plurality of anti-rotation flats  70  configured to cooperate with flats  72  in the counterbore  67  of the lower grip portion  28 , which is also D-shaped, thereby preventing rotation of the locking drum  62  relative to the lower grip portion  28 . 
     A spring  74  includes a first end  76  received within an opening  77  defined by the protrusion  66 , and a second end  78  engaging a lip  80  defined within the second pivot opening of the second lobe  56 . The spring  74  biases against the locking drum  62  axially along a first direction toward the first lobe  52  (as shown by arrow  82  in  FIG. 8 ), thereby securing the lower grip portion  28  in one of a plurality of angular positions. In this first, static or locked position of the locking device  44 , the circumferentially spaced locking teeth  68  of the locking drum  62  are engaged with the cooperating teeth  51  of the upper grip portion  26 . When the spring  74  is compressed axially in a second direction (as shown by arrow  84  in  FIG. 9 ) by depressing the push button  40 , the locking drum  62  is in axially moved away from the first lobe  52 , wherein the lower grip portion  28  can be adjusted to a different angular position relative to the upper grip portion  26 . In this second, actuated or released position of the locking device  44 , the circumferentially spaced locking teeth  68  of the locking drum  62  are disengaged from the cooperating teeth  51  of the upper grip portion  26 . 
     With further reference to  FIGS. 5 and 6 , the push button  40  is secured to the locking drum  62  via a fastener, such as a drum screw  86 . More particularly, the threaded shank  88  of the drum screw  86  is coupled to a threaded insert  90  which is coupled to the push button  40 , illustratively through a friction fit. More particularly, the threaded insert  90  may be a split sleeve  91  that receives the screw  86  and expands within the push button  40  as the screw  86  is threaded therein. Outer surface of the sleeve  91  may include a textured outer surface to increase frictional engagement between the insert  90  and the push button  40 . 
       FIGS. 5 and 6  illustrate an embodiment where the spring  74  is biased by second end  78  engaging the lip  80  within the pivot opening  58 . A cap or plug  92  includes retention arms  94  that are received within the first end  76  of the spring  74 . The cap  92  is configured to cover the pivot opening  58  in the lower grip portion  28 , thereby preventing debris from entering the locking device  44 . A flexible elastomeric membrane  95  ( FIG. 8 ) may be placed over the outer end of the push button  40  to prevent debris from entering the locking device  44 . 
       FIG. 8  illustrates the locking device  44  in the first, static or locked position where the locking drum  62  secures the lower grip portion  28  in a desired angular position relative to the upper grip portion  26 . More particularly, the spring  74  biases the locking drum  62  in the direction of arrow  82 , thereby forcing the teeth  68  of the locking drum  62  into axial engagement with the cooperating teeth  51  of the upper grip portion  26 .  FIG. 9  illustrates the locking device  44  in the second, actuated or released position where the locking drum  62  releases the lower grip portion  28  for angular adjustment relative to the upper grip portion  26  around the pivot axis  38 . More particularly, a force applied by a user to push button  40  in the direction of arrow  84  (i.e., depressing the push button  40 ), forces the teeth  68  of the locking drum  62  away from the cooperating teeth  51  of the upper grip portion  26 . It should be appreciated that the size and spacing of the teeth  51  of the upper grip portion  26  and the teeth  68  of the locking drum  62  determine the number and angular dimensions of available positions of the lower grip portion  28  relative to the upper grip portion  26 . 
       FIG. 10  shows a further illustrative embodiment handgrip  24 ′ where the lower grip portion  28 ′ includes an upwardly extending center arm or lobe  46 ′ received within a slot or channel  60 ′ defined by first and second arms or lobes  52 ′ and  56 ′ extending downwardly from the upper grip portion  26 ′. 
       FIG. 11  shows another illustrative embodiment handgrip  24 ″ including a spring retention cap  96  and a button retention cap  98 . The spring retention cap  96  is threadably received within the pivot opening  58 ″ of the lobe  56 ″. The spring  74  is retained along the pivot axis  38  between the locking drum  62  and the spring retention cap  96 . The button retention cap  98  is threadably received within the pivot opening  54 ″ of the lobe  52 ″ and concentrically receives a reduced diameter end portion  100 . A lip  102  is defined by the end portion  100  and engages the button retention cap  98  to axially retain the push button  40 ″ within the lower grip portion  28 ″. 
     With further reference to  FIGS. 1-6 , an illustrative assembly method of the handgrip  24  will be further detailed. The illustrative assembly method includes the steps of coupling the upper grip portion  26  to the receiver body  12  of the firearm  10 . More particularly, the safety selector detent  32  and the safety selector detent spring  34  are illustratively received within the bore  36 . The upper grip portion  26  receives the mounting tab  25  of the receiver body  12  and is secured to the receiver body  12  by the screw  30 . 
     The assembly method continues by axially compressing the spring  74  and inserting it within the center slot  60  of the lower grip portion  28 , with the second end  78  of the spring  74  engaging the lip  80  of the second lobe  56 . With the spring  74  still compressed, the locking drum  62  is then placed within the center channel  60  of the lower grip portion  28 , with the locking teeth  68  facing toward the teeth  51  of the first lobe  52 . The opening  77  within the locking drum  62  receives and engages radially with the first end  76  of the spring  74 . The anti-rotation flats  70  of the protrusion  66  cooperate with flats  72  in the counterbore  67  of the lower grip portion  28 , thereby preventing rotation of the locking drum  62  relative to the lower grip portion  28 . With the spring  74  compressed and the locking drum  62  fully depressed within counterbore  69 , the assembly method continues by inserting the center lobe  46  of the upper grip portion  26  within the channel  60  intermediate the first outer lobe  52  and the second outer lobe  56  of the lower grip portion  28 . The first pivot opening  48  of the center lobe  46  is aligned with the second pivot opening  54  and the third pivot opening  58 . When properly aligned, locking teeth  68  of the locking drum  62  will engage or mesh with cooperating teeth  51  in the center lobe  46 . 
     Next, the threaded insert  90  is inserted within the push button  40 , and then inserted into the aligned second pivot opening  54  of the first outer lobe  52  and the first pivot opening  48  of the center lobe  46 . The screw  86  is then inserted through the third pivot opening  58  of the second outer lobe  56  and threaded into the insert  90 , thereby securing the locking drum  62  to the push button  40 . The cap  92  is then inserted within the third pivot opening  58  of the second outer lobe  56 , where the arms  94  are secured within the first end  76  of the spring  74 . 
     A further embodiment of assembling the handgrip  24 ″ as illustrated by  FIG. 11  includes threadably inserting the spring retention cap  96  into the opening  58 ″ of the lobe  56 ″ to engage the spring  54  and bias it in a second direction away from the cap  96 . A further embodiment of assembling the handgrip  24 ″ includes threadably inserting the push button retention cap  98  into the lobe  54 ″ to engage the push button  40 . 
     With further reference now to  FIGS. 1-6 , an illustrative operating method of the handgrip  24  will be further detailed. In the static or locked position of the locking device  44 , the lower grip portion  28  is secured from moving relative to the upper grip portion  26 . More particularly, the teeth  68  of the locking drum  62  engage with the teeth  51  of the upper grip portion  26  to prevent relative rotation therebetween ( FIG. 8 ). The illustrative operating method includes the steps of the user depressing the push button  40  to move the locking device  44  to the actuated or released position, wherein the locking device  44  releases the lower grip portion  28  for rotational movement about the pivot axis  38  relative to the upper grip portion  26 . More particularly, the teeth  68  of the locking drum  62  are moved into axially spaced relation to the teeth  51  of the lower grip portion  28  to permit relative rotation therebetween ( FIG. 9 ). 
     The operating method continues by the user rotating the lower grip portion  28  of the handgrip  24  relative to the upper grip portion  26  to the user preferred angle of use, while continuing to depress the push button  40 . Next, the user releases the push button  40  thereby causing the locking device  44  to return to the static or locked position ( FIG. 8 ). More particularly, the teeth  68  of the locking drum  62  are biased by the spring  74  toward the teeth  51  of the upper grip portion  26 . As such, the lower grip portion  28  is secured at the user desired angle relative to the upper grip portion  26 . 
     As may be appreciated, the adjustable handgrip  24  provides an ability to change the grip angle of the lower grip portion  28  and better accommodate different shooting stances, and to make slight incremental adjustments of the grip angle of the lower grip portion  28  while in the field. By rotating the lower grip portion  28  relative to the upper grip portion  26  of the handgrip  24 , wrist fatigue and injury can be minimized by permitting the shooter to hold the firearm  10  at or closer to a natural wrist position. If desired, one available position could be to fold the upper grip portion  26  of the handgrip  24  upwardly for more compactness while being carried and/or concealed. 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the spirit and scope of the invention as described and defined in the following claims.