Abstract:
A handgrip apparatus for firearm includes a hollow housing defining a handgrip surface and forming an enclosure. A fastener is connected to the housing for removably attaching the handgrip apparatus to a fore-end portion of a firearm. A retractable leg assembly is movable between a retracted position and an extended position and includes a pair of pivoting legs usable as a bipod support when the leg assembly is in the extended position.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit under 35 U.S.C. §119(e) of U.S. provisional application Ser. No. 60/555,279 filed Mar. 22, 2004. The aforementioned provisional application is incorporated by reference in its entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to a combination hand grip and bipod for firearm, as well as a method of supporting a firearm using same. The present invention is convertible between a hand grip and a bi-pod or rest, and finds wide utility for use in connection with firearms, including without limitation, military and police use and training, hunting, target shooting, and the like. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention. 
       FIGS. 1 and 2  illustrate the removable hand grip according to an embodiment of the present invention, which is shown attached to a weapon via an accessory mount rail interface, such as a Picatinny rail interface, wherein the extendable legs are retracted for use in standard operation. 
       FIGS. 3 ,  4 , and  5  are front, side, and perspective views of the hand grip apparatus embodiment of  FIGS. 1 and 2 , wherein the legs are in the retracted position. 
       FIGS. 6 ,  7 , and  8  are front, side, and perspective views of the hand grip apparatus embodiment of  FIGS. 1 and 2 , wherein the legs are in the extended position for supporting the barrel or stock of a firearm on a generally horizontal surface. In a preferred aspect, the support surface may be the ground, e.g., for so-called “over-the-beach” targeting or wherein the user is otherwise in a prone position. 
       FIG. 9  is a side sectional view of the latch release assembly taken along the lines  9 - 9  shown in  FIG. 3 . 
       FIG. 10  is a fragmentary illustration showing the latch and leg assemblies. 
       FIG. 11  is an exploded view of the handgrip apparatus. 
       FIG. 12  illustrates a handgrip apparatus according to a second embodiment. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawing figures, a hand grip apparatus  100  is provided which may be mounted to an accessory rail interface assembly  102  of a weapon  104  of a type having a butt stock  105  and a rear pistol grip  107  adjacent a trigger  109 . Although the embodiment depicted in  FIGS. 1 and 2  is shown attached to the fore portion of an M4A1 rifle having a Picatinny rail interface (e.g., as specified in MIL-STD-1913), it will be recognized that the present invention may be adapted for use with all manner firearms, including without limitation rifles, handguns, machine guns, mortars, etc., and all manner of weapon accessory mount rail interfaces or mounting systems. 
   The hand grip  100  converts between a hand grip mode of operation and a bi-pod mode of operation. In the handgrip mode of operation, the handgrip  100  is used as a conventional generally vertical hand grip (see  FIG. 1 ), e.g., wherein (for a right-handed marksman) the handgrip  100  is grasped by the left hand and the pistol grip  107  is grasped by the right hand, with the butt stock  105  held against the right shoulder. In the bi-pod mode of operation, the hand grip device  100  functions as a gun rest to support the front of the weapon above a support surface during targeting or shooting operations (see  FIGS. 6-8 ). While the bi-pod legs of the depicted embodiment may advantageously be employed to support the fore end of a firearm on the ground by a user in a prone position, it will be recognized that the support legs may be used to support a firearm on any generally horizontal surface on which is may be desired to support a firearm, such as tabletops, benches, floors, the ground, pavement, and the like. 
   The hand grip  100  extends generally perpendicular to the rail interface, and in a preferred embodiment, is angled toward the user to minimize bending of the user&#39;s wrist, preferably about 3-12 degrees with respect to the barrel, and more preferably about 5 degrees. As used herein, the term “vertical hand grip” is not intended to preclude such variations. 
   The hand grip  100  includes a hand grip housing  110 , a rail clamp assembly  112 , a retractable leg assembly  114 . A latch release assembly  116  is mounted within the housing  110 . 
   The housing  110  may be made of any rigid material, and in a preferred embodiment is made from aluminum, more preferably light weight aircraft aluminum. The hand grip assembly may include circumferential grooves, ridges, knurls, or other hand grip features. Also, the housing  110  may be textured, e.g., via sandblasting, to improve grip. In the depicted embodiment, an optional recess  118  is provided on the front side of the housing  110  for receiving the user&#39;s index finger. Optionally, additional finger recesses for additional fingers may also be provided. Optionally, a soft or resilient material (not shown) may be provided on the exterior of housing  110 . 
   The hand grip  110  may be generally tubular and is closed at a first end  120  which is proximal to the mounting rail  102  when mounted on a weapon. The rail clamp assembly  112  (which can best be seen in  FIG. 11 ) includes a first rail grabber  122  which is preferably permanently attached to the housing  110  and which is preferably integrally formed therewith. A second rail grabber  124  is mounted on a threaded rod  126 , which is mounted on the proximal end  120  of the housing  110 . The threaded rod  126  passes through an opening  128  in the second rail grabber  124  and is received within an opening  130  in the first rail grabber  122 . The threaded rod  126  partially rests in a groove  132  formed on the housing end  120  and is secured via a fastener  138 , such as a threaded fastener, passing through the first rail grabber, the threaded rod, and into the housing  110 . The second rail grabber  124  is moveable along the threaded rod  126 . 
   In operation, the first and second rail grabbers  122  and  124  are placed on opposite transverse sides of a rail to be mounted and cooperate to removably secure the apparatus  100  to a rail interface. An internally threaded nut  134  may be rotated about the threaded rod  126  to urge the second rail grabber toward the first rail grabber to provide a clamping action about the rail interface ( 102 ). The threaded interface depicted includes an alternating series of protrusions  106  and recesses  108  (see  FIG. 2 ). 
   When mounted, the threaded rod  126  extends into a selected one of the recesses  108  (selected in accordance with a user&#39;s desired longitudinal position of the hand grip  110  on the weapon  102 ) to further secure the hand grip  110  to the accessory rail and prevent any movement there along. In the depicted embodiment, the threaded rod  126  includes a shaped portion  127  complimentary with the recesses  108 . It will be recognized that the fastening system may be modified to accommodate other rail interface systems. 
   In the preferred embodiment shown, the nut  134  rotates relative to the threaded rod  126 . Optionally, a protrusion on the threaded rod  126 , a threaded fastener or lug (not shown), or other means for preventing complete removal of the nut  134  from the threaded rod  126  may be provided. 
   The latch assembly  116  is mounted interiorly within the proximal end of the housing  110 . The latch assembly  116  is secured within the housing  110  via one or more threaded fasteners  140 . The latch assembly  116  includes a latch member  142  slideably captured between a first and second latch assembly housing members  144  and  146 , respectively. Each of the first and second latch assembly housing members  146  and  144  include aligned openings  148  and  150  passing therethrough. The latch member  142  includes a push button  152  which passes through an opening  153  in the housing  110 , preferably disposed at a position the opposite the grip recess  118 . The latch member  142  includes an opening  154 . A spring  156  is captured between the latch housing members  146  and  144  and urges the latch member  142  outwardly such that the opening  154  is urged out of alignment with the openings  148  and  150 . Pressing the button  152  against the bias of the spring  156  brings the opening  154  into alignment with the openings  148  and  150  thereby releasing the leg mechanism  114  as will be described in further detail below. In certain embodiments, the latch release button  156  is located at a position on the handgrip surface so as to be accessible by an operator&#39;s thumb when the operator&#39;s hand is closed about the housing. 
   As can best be seen in  FIGS. 9 and 10 , which shows the leg assembly  114  retracted and engaging the latch assembly  116 , the leg assembly  114  includes a locking pin  160  which passes through the openings  148 ,  154 , and  150  of the latch assembly  116 . The pin  160  includes a tapered or generally conical end  162 . The end  162  includes a base flange  164  which may engage the  15  upper surface of the latch member  142  to prevent passage therethrough unless the push button  152  is depressed by the user to bring the opening  154  into alignment with openings  150  and  148 . On the lower surface of the latch  142 , the peripheral edge of the opening  154  may be counter-sunk, beveled, rounded, etc., so as to cooperate with the tapered end  162  of the pin  160  to facilitate passage of the tapered end  162  of the pin  160  in the upward (in the orientation shown) direction. 
   The pin  160  passes through a central opening in a spring flange  170  and may be secured by a fastener such as a retaining pin  172 . A coaxial spring  174  engaging the spring flange  170  and latch assembly housing base  144  is compressed when the leg assembly  114  is in the retracted position. The compression of the spring  174  causes the leg assembly  114  to be urged downward into the extended or open position (see  FIG. 2 ) when the button  152  is depressed, thus bringing the opening  154  into alignment with the openings  150  and  148 . To retract the bipod legs, the legs are simply collapsed and reinserted into the housing  110 , against the bias of the spring  174 , wherein the pin  160  engages the latch assembly  116  as described above. 
   The spring flange  170  is mounted on the upper end of an axial rod  176 , which may be integrally or separately formed with the spring flange  170 . The rod  176  includes an elongated opening  178 . Two leg spreader arms  180  are pivotally attached to the lower end of the rod  176  and pivot about pivot pin  177 . A leg mounting member  182  includes first and second hinge members  184 , to which are hingedly attached to first and second legs  186 . Legs  186  pivot about pivot pins  188  between a retracted or closed position and an extended or open position. The spreader/brace members  180  also pivotally attach to an inward facing side of the legs  186  at pivot point  190 . The pivotal attachment of the spreader arms  180  can best be seen in  FIG. 11 . 
   The base of the spring flange  170  rests within a recess  192  formed on the upper surface of the leg mounting member  182  when the legs are fully extended. The leg mounting member  182  acts as a stop, limiting the pivoting range of motion of the legs  186 . A pin  194  is secured to the leg mounting member  182  and passes through the elongate opening  178  to capture the spring flange  170 . The retaining pin travels generally confined to the length of the elongate opening  178  when the legs are moved between the extended and retracted positions. The legs  186  are pivotally attached at their lower ends to pivoting feet  196 . Each of the feet  196  pivot about a respective pivot pin  198 . Springs  200  are provided to pivotally urge the feet into a closed position (see  FIG. 11 , thereby maintaining the feet within the overall footprint of the hand grip when the feet are retracted. When the legs are extended, and placed on a support surface, the weight of the weapon causes the feet to pivot against the bias of the springs  200  to align the feet with the support surface. The feet  196  may be made of any suitable material, including plastics, composite materials, metals, and so forth. The lower surface of the feet  196  may be grooved or otherwise textured to prevent slippage on the support surface. 
   An internally flanged base member  202  (as best seen in  FIG. 11 ) is secured to the distal housing end  220  to provide retention of the leg assembly  114  within the housing  110  when the leg assembly  114  is in the open position. A stop member  204  received within the base member  202  includes two oppositely disposed stops  208  extending inwardly. The underside surface  210  of the leg mounting member  182  abuts the stop member  204  when the legs are in the fully open position. The stop members  208  allow a desired degree of rotation of the leg assembly relative to the housing portion  110 . The relative rotation permits the weapon to be horizontally pivoted to engage the target without the need to move or shift the feet relative to the underlying support surface. The legs  186  and/or leg hinge members  184  cooperate with the stop members to limit range of rotation. The stop members  208  may be sized and/or configured to permit some desired or predetermined degree of rotation. 
   The stop member  204  and the distal housing end may include aligned or mating surface features to retain the stop member  204  at the desired orientation with respect to the housing and to prevent relative rotation of the stop member  204  relative to the housing  110 . In the preferred embodiment, one or more (two in the illustrated embodiment) protrusions or bosses  215  on the stop member  204  engage complimentary grooves or depressions  213  formed on the housing  110 . Alternatively, one or more protrusions may be formed on the housing  110  and complimentary aligned openings or depressions may be formed on the stop member  204 . Other means for aligning and preventing rotation of the stop member  204  are also contemplated, such as a “keyed” peripheral shape which is complimentary with a corresponding feature on the housing  110  distal end  220 . 
   The base ring  202  may be secured to the housing via any of a number of means. For example, the base ring  202  may contain internal threads which mate with threads  212  provided on the distal housing end  220 . Alternatively or additionally, other fasteners such as set screws, adhesives, clips, dogs, pawls, or the like, or combinations thereof, may be used. 
   In the depicted embodiment, the handgrip housing  110  includes optional surfaces or recesses  222  for receiving an optional switch  224 . An alternative handgrip apparatus embodiment  100 ′ which is generally as described above by way of reference to the handgrip apparatus  100 , but which lacks the switch  224  and switch mounting surface  222  is shown in  FIG. 12 . 
   The switch  224 , which may be a mechanical contact switch, is provided for actuating an electronic accessory mounted on the weapon  104 , such as a laser sight module, light source for target illumination, or other electronically operated accessory. The switch  224  includes a connector  226  for removably electrically coupling the switch  224  to the accessory. In one embodiment, the switch  224  includes normally open contacts and is resiliently depressible to close the contacts for actuating an attached accessory, although other switch configurations are also contemplated. 
   In the depicted preferred embodiment, the handgrip housing includes mounting surfaces  222  on opposite transverse sides of the handgrip surface for left- or right-side mounting. In the depicted embodiment, the switch  224  may be removably attached to the housing  110  by bands, cables, ties, etc.,  228  encircling the handgrip housing  110  and switch member  224 . The bands  228  engage grooves or recesses  230  formed in the housing  110 . Of course, other fastener types may be employed, such as clips, clasps, adhesive fasteners, or snap-fit or otherwise complimentary mating features formed on the housing  110  and switch  224 . 
   In the embodiment illustrated in  FIG. 1 , the switch  224  appears on the right side of the handgrip housing  110 . In operation, the left hand of a right-handed marksman is closed about the handgrip housing  110  such that the user&#39;s fingertips are on the switch  224 . The laser sighting module or other accessory may then be actuated by increasing the gripping force by an amount sufficient to close the contacts. It will be recognized that other switch types and configurations may be employed. 
   The invention has been described with reference to the preferred embodiments. Modifications and alterations will occur to others upon a reading and understanding of the preceding disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.