Abstract:
Adapter devices, apparatus, systems and methods of allowing a firearm to be supported by a foldable fore grip/gun handle. The fore grip gun handle can have bipod type legs that can be extendable from the handle. The fore grip handle can be just a vertical extension. The adapter can allow for the fore grip/gun handle to move from a fold back position along the bottom of the firearm so that the firearm can be easily carried, and the adapter to can allow for the handle to move down to a vertical support position beneath the firearm when the firearm is to be used. The adapter can also support a light in both a folded position and in a downwardly extended position, where light can be aimed forward, rearward to the side and/or pointed down from the firearm. The adapter can allow for a dual functioning component that can be either or both a fore grip and/or a light source.

Description:
This is a Divisional of Application Serial No.: 11/934,392 filed on Nov. 2, 2007 now U.S Pat. No. 7,861,451, now allowed which claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/905,556 filed Mar. 7, 2007, and this invention is a continuation in part of U.S. patent application Ser. No. 11/652,337 filed Jan. 11, 2007, now U.S. Pat. No. 7,568,304 which is a continuation in part of U.S. patent application Ser. No. 11/485,762 filed Jul. 13, 2006, now U.S. Pat. No. 7,490,429, which is a continuation in part of U.S. patent application Ser. No. 10/725,082 filed Dec. 2, 2003, now U.S. Pat. No. 7,111,424, and U.S. Design patent application Ser. No. 29/259,347 filed May 5, 2006, now U.S. Pat. No. D566,219. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to guns and firearms and more particularly to devices, apparatus, systems and methods of allowing a firearm to be supported by a fore grip/gun handle that can have bipod type legs or only a vertical extension, where the fore grip/gun handle can fold back along the firearm, and for allowing accessories such as a light or a combination fore grip and light to be foldable underneath the firearm. 
     BACKGROUND AND PRIOR ART 
     For many years, there has been considerable amount of prior art for fore grips and bipod devices, that date back to pre-20 th  century times, with bipods having a familiar appearance, structure and configuration, where the fore grips and bipods are generally kept in a vertical orientation beneath the firearm. 
     For example, some known prior art includes but is not limited to U.S. Pat. Nos. 271,251; 1,295,688; 1,355,660; 1,382,409; 1,580,406; 2,386,802; 2,420,267; 2,436,349, and 3,235,997. These patents disclose the respective art in relation to bipods, but do not disclose a fore grip or gun handle with a concealable and collapsible bipod. 
     U.S. Pat. No. 6,487,807 describes a tripod gun handle that provides a combination pistol grip and pivotal tripod. An examination of this patent reveals a number of problems with this device, and the most obvious problem is that the tripod legs are positioned on the exterior of the handle when not deployed. If the gun with this device attached was being used in wet or muddy environments, either in a deployed or storage position, the ingress of mud and dirt into and around the handle could result in the deployment and storage of the tripod legs being severely restricted due to the mud or foreign matter. Another problem is that deployment requires the rotation of a disengagement cam to force the legs into their deployed position and then a leg locking assembly is rotated to lock the legs into a locked position. Two separate actions are required to deploy and lock the tripod legs into a locked position. 
     Another problem with these bipods and leg stands is that the fore grip type stands are generally locked in a fixed position, which means an operator would have to physically move and/or physically raise the stand to adjust the firearm to fire a shot. Such physical movements of having to physically cant, tilt and/or lift the stand would be naturally uncomfortable to the operator. In addition such physical movements can cause the firearm to be held in an unsteady position that makes both a steady and reliable shot at an intended target both difficult and potentially impossible. 
     Another problem with many firearms having fore grips and bipods is that the fore grips remain in fixed vertical type orientations beneath the firearm at all times. Thus, these firearms can be cumbersome to carry since the fore grip is sticking down which can hit or rub against the sides of the human carrier. Also the fixed vertically oriented fore grips make the firearms difficult to store and transport since the lower extending vertical fore grip takes up valuable space and room during transport. 
     Attempts over the years have been made to allow for allowing for some folding of portions of firearms. See for example, U.S. Pat. Nos. : 4,351,224 to Curtis; 4,625,620 to Harris; 5,074,188 to Harris; 5,085,433 to Parsons; 5,711,103 to Ken; 6,470,617 to Gregory; 6,517,133 to Seegmiller et al.; and 6,763,627 to Kaempe. However, none of these references overcomes all of the problems with the prior art described above. 
     Thus, the need exists for solutions to the problems addressed above. 
     The novel invention allows stands such as bipods to be able to fold as desired by the firearm operator. 
     SUMMARY OF THE INVENTION 
     A primary objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip/gun handle that can fold up along the firearm when not being used. 
     A secondary objective of the subject invention is to provide devices, apparatus, systems and methods of a detachable firearm fore grip/gun handle that can fold down to extend vertically below when the firearm is being used. 
     A third objective of the subject invention is to provide devices, apparatus, systems and methods of using a firearm fore grip/gun handle with extendable bipod legs. 
     A fourth objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip/gun handle that allows for a light to be attached to the fore grip/gun handle. 
     A fifth objective of the subject invention is to provide devices, apparatus, systems and methods of incorporating a light into a firearm fore grip/gun handle. 
     A sixth objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip gun handle with a pivotable light. 
     A seventh objective of the subject invention is to provide devices, apparatus, systems and methods of attaching and using a firearm fore grip gun handle with a foldable light. 
     A firearm fore grip adapter having an adapter member, an upper portion on the adapter member for allowing the member to be attachable beneath a firearm, and a lower portion pivotally attached to the adapter member, the lower portion for supporting a fore grip thereon, wherein the fore grip can move between a vertical downward position for supporting the firearm to a folded position with fore grip adjacent to the firearm. The upper portion can be an upper clamp for clamping the adapter member underneath of the firearm. 
     The upper clamp can include clamp edges for sliding about picatinny rails underneath the firearm. The upper clamp can include compressible clamp edges for clamping about picatinny rails underneath the firearm with a rotatable knob/screw. 
     The lower portion can include rails for allowing the adapter to attach to detachable fore grip. The adapter can include a pullable button for releasing the pivotable lower portion. The adapter can include a depressible button for releasing the pivotable lower portion. The adapter can include a switch for releasing the pivotable lower portion. 
     The fore grip can have bipod legs. The fore grip can have a light. 
     The invention can include an adapter member, an upper portion on the adapter member for allowing the member to be attachable beneath a firearm, and a lower portion pivotally attached to the adapter member, the lower portion for supporting another component thereon, wherein the other component can move between a vertical downward position for to a folded position adjacent to the firearm. 
     The another component can include a light. The another component can include a vertical fore grip. The another component can include both a vertical fore grip and a light. The another component can include a vertical fore grip with a light integrated inside of the fore grip. 
     A novel method of attaching a foldable accessory mounting plate to a firearm, can include the steps of providing a firearm having opposite facing picatinny rails underneath the firearm, providing a top plate member with an upper surface having a pair of opposite facing grooves, providing a bottom plate member with opposite facing picatinny rails, hingedly attaching one end of the bottom plate member to the top plate member by the hinge, sliding and mating the opposite facing grooves on the upper surface of the top plate member about the picatinny rails underneath the firearm, providing a vertically extending elongated accessory having an upper surface having a pair of opposite facing grooves, sliding and mating the opposite facing grooves on the upper surface of the elongated accessory about the picatinny rails on the bottom plate member, and folding the vertically extending elongated accessory to a horizontal orientation underneath the firearm by the hinge between the top and the bottom plate member. 
     The accessory can include a light. The accessory can include vertical fore grip. The method can include the steps of deploying a pair of legs with feet beneath the vertical fore grip and expanding the feet on the legs apart from one another. The vertical fore grip can include a light. 
     Another embodiment of the invention can have telescoping extendable legs that can be individually extended from beneath the fore grip handle. 
     The invention can be used with fore grips having concealable and collapsible bipod legs. Alternatively, the accessory mount can be used with other types of fore grips such as basic vertical fore grips, or any stands that can be attached to rails such as picatinny rails beneath firearms. 
     A firearm fore grip with accessory mount holder, can include an elongated handle w having a top end and a bottom end and outer sidewalls between the top end and the bottom end, and an accessory mount having a portion that is attached to a portion of the outer sidewalls of the handle, the accessory mount having rails for allowing an accessory to be removably attached to the rails on the accessory mount. 
     The accessory mount can be molded to a side portion of the outer sidewalls of the handle. 
     Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment, which is illustrated in the accompanying flow charts and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Referring particularly to the drawings for the purposes of illustration only, and not limitation: 
         FIG. 1  is a bottom rear right perspective view of a folding stacking unit. 
         FIG. 2  is a bottom front left perspective view of the stacking unit of  FIG. 1 . 
         FIG. 3  is a top rear right perspective view of the stacking unit of  FIG. 1 . 
         FIG. 4  is top front left perspective view of the stacking unit of  FIG. 1 . 
         FIG. 5  is a rear end view of the stacking unit of  FIG. 1 . 
         FIG. 6  is a left side view of the stacking unit of  FIG. 1 . 
         FIG. 7  is a front end view of the stacking unit of  FIG. 1 . 
         FIG. 8  is a top view of the stacking unit of  FIG. 1 . 
         FIG. 9  is a bottom view of the stacking unit of  FIG. 1 . 
         FIG. 10  is an exploded perspective view of the stacking unit of  FIG. 1 . 
         FIG. 11  is an exploded perspective view of the stacking unit of  FIG. 1 . 
         FIG. 12  is an enlarged rear end view of the stacking unit of  FIGS. 1 ,  5 . 
         FIG. 13  is an enlarged left side view of the stacking unit of  FIGS. 1 ,  6 . 
         FIG. 14  is a cross-sectional view of the stacking unit of  FIG. 12  along arrows  14 X. 
         FIG. 15  is a rear view of the preceding stacking unit with pivot rail folded forward. 
         FIG. 16  is a left side view of  FIG. 15 . 
         FIG. 17  is a cross-sectional view of  FIG. 15  with pivot rail folded forward. 
         FIG. 17A  is an enlarged view of the rail mount plate, release button, pivot rail latch, release button finger access slot and latch spring shown in  FIG. 17 . 
         FIG. 18  is another cross-section view of  FIGS. 15 ,  17  with pivot rail being folded. 
         FIG. 18A  is an enlarged view of the rail mount plate, release button, pivot rail latch, release button finger access slot and latch spring shown in  FIG. 18 . 
         FIG. 19  is another cross-section view of  FIGS. 15 ,  18 - 18  with pivot rail locked. 
         FIG. 19A  is an enlarged view of the rail mount plate, release button, pivot rail latch, release button finger access slot and latch spring shown in  FIG. 19 . 
         FIG. 20  is a rear bottom right perspective view of the folding stacking unit attached to a vertical fore grip, with the stacking unit mounted to a picatinny rail of a firearm. 
         FIG. 21  is a front bottom left perspective view of  FIG. 20  showing the folding stacking unit attached to a vertical fore grip, with the stacking unit mounted to the firearm. 
         FIG. 22  is a rear top right perspective view of the folding stacking unit attached to fore grip, with the stacking unit mounted to a picatinny rail of a firearm of  FIG. 20 . 
         FIG. 23  is front top left perspective view of the folding stacking unit attached to a vertical fore grip, with the stacking unit mounted to the firearm of  FIG. 21 . 
         FIG. 24  is side view of bipod vertical fore grip detached from the stacking unit that is mounted beneath the firearm. 
         FIG. 25  is another side view of  FIG. 24  with the fore grip mounted to the stacking unit. 
         FIG. 25A  is an enlarged view of the fore grip mounted to stacking unit of  FIG. 25 . 
         FIG. 26  is another view of  FIGS. 24-25  with fore grip in folded position to firearm. 
         FIG. 26A  is an enlarged view of the folded fore grip and mounting plate of  FIG. 26 . 
         FIG. 27  is a side view of a foldable light/foldable fore grip with light detached from a stacking unit that is mounted beneath a firearm. 
         FIG. 28  is another view of  FIG. 27  showing the light/fore grip with light, attached to the firearm mounted stacking unit, with light/fore grip with light, in folded position. 
         FIG. 29  is another view of  FIGS. 27-28  with light/fore grip with light in downward extended position, with the light being useable as a map light, or the light being used as a vertical fore grip. 
         FIG. 30  shows a novel combined vertical fore grip with built in-light. 
         FIG. 31  is a side cross-sectional view of the interior of the fore grip light of  FIG. 30 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Before explaining the disclosed embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation. 
     The invention claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/905,556 filed Mar. 7, 2007, and this invention is a continuation in part of to U.S. patent application Ser. No. 11/485,762 filed Jul. 13, 2006, which is a continuation in part of U.S. Patent Application Ser. No. 10/725,082 filed Dec. 2, 2003, now U.S. Pat. No. 7,111,424, and U.S. Design patent application Ser. No. 29/259,347 filed May 5, 2006, all by the same inventors and assigned to the same assignee, which are all incorporated by reference. 
     The inventors of the subject invention have to date patented at least one U.S. Pat. No. 7,111,424 to Gaddini, which is incorporated by reference. This patent includes a replaceable mounting assembly that allows for mounting of the gun handle by various means to a gun. A fore grip or gun handle, designed with ergonomic reasons in mind, provides a stable means of holding the gun. A plurality of legs that are concealed within the fore grip are coupled via a hinge to a spring piston assembly. A spring-loaded fulcrum release mechanism holds the piston assembly in a compressed and locked position. 
     When the piston assembly is released upon activation of the spring-loaded fulcrum release mechanism, the legs are driven downwards by the piston and upon being released from the confinement of the fore grip are deployed outwards to a locked position by a hinge or pivot mechanism. The legs have feet that are designed so that, when the legs are concealed within the handle, the feet seal off the deployment and spreader mechanisms from entrance of any debris, material etc that may interfere with the deployment of the bipod. 
     As shown in the figures, the invention can be used with the inventors novel fore grip that has a mounting section or end having parallel rails that can be attached to rails, such as picatinny rails on a firearm such as a rifle, and the like, by adjusting the head piece clamps with rail clamp bolt. The fore grip can include of a machining or a casting that utilizes aluminum or a molding that utilizes high impact resistant polymer or a composite material. The fore grip is a grip for gripping by the hand of a user when the fore grip is attached to the firearm. 
     Although the mounting end is shown as being an integral part of the handle for illustration purposes only, it should be understood that the mounting end head piece can be a separate component that is then attached by other members, such as threads or a lock screw or locking bolt to the handle. For illustrative purposes, the mounting end head piece uses a picatinny mounting rail (MIL-STD-1913 rail), a mounting system widely used by military for attachment of various devices to military rifles. However, it should be understood that other methods of attachment to a firearm could be used. 
     As described in the parent patent applications that are incorporated by reference, the fore grip can have a handle portion, with bottom retaining cap have a concealable and collapsible bipod legs. One version can have a tubular recess consisting of a first cylindrical cutout housing the bipod legs when concealed and a sliding piston that deploys the legs and a second cylindrical cutout housing a release mechanism and a void space for other accessories. The release mechanism such as a depressible button has a compression spring positioned between the piston assembly and the bottom of the first cylindrical cutout and the compression spring. The legs are connected to the bottom of the piston assembly via a hinge and spring that when released from confinement within the fore grip, causes the legs to expand outward until deployed. 
     Another version of the fore grip with bipod uses only one spring, wherein the legs can be gravity and/or snap/shook released from the handle by a switch (such as the depressible button) and the spring expands the legs out to the fully deployed position. 
     To use the fore grip, a user simply attaches the fore grip to the firearm, regardless of whether or not the bipod legs are deployed. If the legs are deployed, then the user has the option of using the gun with the legs deployed or compressing or squeezing the legs together, and pushing them upwards into the fore grip until the male part of the spring-loaded fulcrum release mechanism catches and locks the bipod legs and the piston assembly into the closed position. 
     As described above, the invention can be used with the inventors&#39; novel bipod fore grip shown in the figures. A preferred embodiment can have the head piece having a length of approximately 1.85 inches a width of approximately 1.29 inches and a height of approximately 1.15 inches. In a fully leg retracted/closed position, the fore grip can have a height of approximately 6.32 inches. The handle portion  110  can have a length of approximately 2.95 inches and a width of approximately 1.37 inches. The legs can have a width of approximately 0.73 inches along with the feet having a width of approximately 0.99 inches. In a fully deployed/expanded position, the fore grip can have an overall height of approximately 8.57 inches, with the legs  120  having a spread eagle angle therebetween of approximately 76 degrees, and the inside angle of the feet  128  to the rest of the legs being approximately 52 degrees. The feet can be spread apart from toe to toe at approximately 6.95 inches. 
     Although, the preferred embodiment lists specific dimensions, the invention can be practiced with different sized and shaped components. 
     The fore grip can be made from various components such as but not limited to polymeric materials, such as but not limited to plastic and/or glass filled nylon with and without metal inserts such as aluminum, galvanized metal, stainless steel, and the like Additionally, the fore grip can include void spaces where possible to decrease weight. 
     Although a depressible button is shown above, the invention can use other types of activation such as but not limited to toggle switches, pressure actuated switches, temperature actuated switches and the like, to release the inside legs to slide down and expand outward from beneath the housing. 
     Folding Stacking Plate Designator Reference Numbers 
     
         
           1000  Folding Stacking Unit 
           1004  Optional clamp turn screws to attach clamps 
           1006  Optional side plate for clamp turn screws 
           1010  Rail Mount Plate/top plate member 
           1012  leg member 
           1013  inwardly facing groove 
           1014  leg member 
           1015  inwardly facing groove 
           1018  notch on lower surface of top plate member 
           1019  pin-hole 
           1020  Pivot Rail Member/lower-bottom plate member 
           1022  Upper pivot rail edge 
           1024  Side Rail 
           1026  Side Rail 
           1028  front tab 
           1029  pin-hole 
           1030  Pivot Pin 
           1040  Release Button 
           1045  fastener (screw, and the like) 
           1050  Pivot Rail Latch 
           1052  Ledge edge of Latch 
           1055  Longitudinal Top Slot 
           1060  Release Button 
           1062  Finger Access Slot of Release button 
           1070  Latch Cover Plate 
           1074  Downwardly protruding pin 
           1075  fastener(s) 
           1075 R threaded receiving holes 
           1080  Picatinny Rail 
           1090  Vertical Fore Grip 
           1100  Latch Spring 
           1110  Latch Catch 
           1200  Firearm (i.e. rifle, etc.) 
           1400  Attachable/detachable light accessory/fore grip with light 
           1450  upper mounting plate with grooves 
           1455  fastening screw knob 
           1500  fore grip with built in light 
           1510  lens 
           1515  light source 
           1520  cap 
           1530  batteries 
           1550  inside of light fore grip 
           1590  depressible switch 
       
    
       FIG. 1  is a bottom rear right perspective view of a folding stacking unit  1000 .  FIG. 2  is a bottom front left perspective view of the stacking unit  1000  of  FIG. 1 .  FIG. 3  is a top rear right perspective view of the stacking unit  1000  of  FIG. 1 .  FIG. 4  is top front left perspective view of the stacking unit  1000  of  FIG. 1 .  FIG. 5  is a rear end view of the stacking unit  1000  of  FIG. 1 .  FIG. 6  is a left side view of the stacking unit  1000  of  FIG. 1 .  FIG. 7  is a front end view of the stacking unit  1000  of  FIG. 1 .  FIG. 8  is a top view of the stacking unit  1000  of  FIG. 1 .  FIG. 9  is a bottom view of the stacking unit  1000  of  FIG. 1 . 
     Referring to  FIGS. 1-10 , stacking unit  1000  can have a rail mount plate  1010  being a top plate member which hingedly attaches to a lower plate member  1040  which functions as a lower plate member by pivot pin  1030 .  FIG. 10  is an exploded perspective view of the stacking unit  1000  of  FIG. 1 .  FIG. 11  is an exploded perspective view of the stacking unit  1000  of  FIG. 1 . 
     Referring to  FIGS. 1-11 , the stacking unit  1000  can include an upper surface with a pair of leg members  1012 ,  1014  each with internal facing side grooves  1013 ,  1015 . The grooves  1013 ,  1015  are inwardly facing clamp edges that can slide about existing picatinny rails underneath of a firearm, such as a rifle and the like, which will be described in greater detail below. The inwardly facing clamp edges  1013 ,  1015  can also include optional clamp turn screws  1004  ( FIG. 20 ) to attach the inwardly facing clamp edges about both sides of the existing picatinny rails underneath the firearm. 
     The stacking unit  1000  can also include a lower plate member  1020  (pivot rail) having opposite facing side rails  1024 ,  1026  that can be similar to or replicate the existing picatinny rails underneath the firearm. The side rails  1024 ,  1026  can be used for mounting a vertical fore grip such as the inventor&#39;s novel bipod fore grip thereon, which is shown below in  FIG. 20 . 
     The lower member  1020  of the stacking unit  1000  can be pivotally mounted to the rail mount plate  1010  by a pivot pin  1030  that passes through pin-hole  1029  of the bottom plate member  1020  and pin-hole  1019  of top plate member  1010 . The fit can be a frictional fit where the operator pulling back on front tab  1028  can extend the pivot rail member (lower member) from a position horizontal to and within the top member (rail plate member)  1010  to a position substantially perpendicular to the rail mount plate member  1010 , where it is held in place by friction. Tab  1028  rests inside of notch  1018  on the lower surface of top plate member  1010  while lower plate member  1020  is perpendicular to top plate member  1010 . 
       FIG. 12  is an enlarged rear end view of the stacking unit  1000  of  FIGS. 1 ,  5 .  FIG. 13  is an enlarged left side view of the stacking unit  1000  of  FIGS. 1 ,  6 .  FIG. 14  is a cross-sectional view of the stacking unit  1000  of  FIG. 12  along arrows  14 X. 
       FIG. 15  is a rear view of the preceding stacking unit  1000  with lower plate member  1020  (pivot rail member) folded forward.  FIG. 16  is a left side view of  FIG. 15 . 
       FIG. 17  is a cross-sectional view of  FIG. 15  with pivot rail member  1020  folded forward.  FIG. 17A  is an enlarged view of the rail mount plate (top plate member)  1010 , release button  1060 , pivot rail latch  1050 , release button finger access slot  1060  and latch spring shown  1100  in  FIG. 17 . 
       FIG. 18  is another cross-section view of  FIGS. 15 ,  17  with pivot rail member (lower plate member  1020 ) being folded.  FIG. 18A  is an enlarged view of the rail mount plate member (top plate member)  1010 , release button  1060 , pivot rail latch  1050 , release button finger access slot  1060  and latch spring  1100  shown in  FIG. 18 . 
       FIG. 19  is another cross-section view of  FIGS. 15 ,  18 - 18  with pivot rail locked.  FIG. 19A  is an enlarged view of the rail mount plate, release button  1060 , pivot rail latch  1050 , release button finger access slot  1060  and latch spring  1100  shown in  FIG. 19 . 
     Referring to  FIGS. 12-18B , pushing the lower plate member (pivot rail member)  1020  in the opposite direction of CL allows the lower member  1020  to pivot back to latch and lock onto the rail mount plate  1010  which is shown in  FIGS. 12-18B  below. 
     As shown in  FIGS. 10-11 , and  17 - 19 A, latch spring  1100  fits inside a top longitudinal slot  1055  within latch  1050 . An inner end of latch  1050  includes a ledge edge  1052  which can latch against upper ledge edge  1022  of pivot rail member  1020  (shown more clearly in  FIGS. 17-19A . A release button  1040  can be held in place by a fastener  1045  such as a screw, and the like, which fastens into threaded surfaces in the end of pivot rail latch  1050  opposite to end having ledge edge  1052 . 
     A downwardly protruding pin  1074  in plate  1076  can fit into longitudinal top slot  1055  of pivot rail latch  1050  and be held in place by fasteners  1075 , such as screws which lock plate  1070  to threaded receiving holes  1075 R in top plate member  1010 . 
     The downwardly protruding pin  1074  is useful so that pivot rail latch  1050  can move to the left and right by the slot  1055  sliding about the downwardly protruding pin  1074 . 
     The operation of using the release button  1060  will know be described in reference to  FIGS. 19A ,  18 A, and  17 A in that order, the release button  1060  can be moved by the operator using a finger inserted into access slot  1062  of the release button  1060  to press against downwardly protruding lip edge  1042  in the direction of arrow R. Mount plate  1010  which is fixably attached to pivot rail latch  1050  contracts against latch spring  1100  while moving ledge edge  1052  away from upper pivot rail edge  1022  of pivot rail member  1020 . This allows the pivot rail member (lower plate member  1020 ) to be able to pivot downward to a vertical position as shown in  FIG. 17 . 
     The pivotable lower plate member  1020  can have a pair of opposite facing rails that can mount to the inventors&#39; bipod with extendable legs, which is shown and described in their previous patent, and other patents pending. 
     Alternatively, the stacking unit  1000  can allow for other fore grips to be mounted thereon. Still furthermore, the stacking unit can be an integral part of a vertical fore grip. 
     While a pullout type switch is shown, the lower portion of the stacking unit can be released with other types of buttons, such as a depressible button, and the like. 
       FIG. 20  is a rear bottom right perspective view of the folding stacking unit  1000  attached to a vertical fore grip  1090 , with the stacking unit  1000  mounted to a picatinny rail  1080  of a firearm (not shown) such as a rifle, and the like. As previously described the clamp screw  1004  can be used to attach the folding stacking unit  1000  by holding an optional side plate  1006  in place. 
       FIG. 21  is a front bottom left perspective view of  FIG. 20  showing the folding stacking unit  1000  attached to a vertical fore grip  1090 , with the stacking unit  1000  mounted to the picatinny rails  1080  of a firearm (not shown) such as a rifle, and the like.  FIG. 22  is a rear top right perspective view of the folding stacking unit  1000  attached to fore grip  1090 , with the stacking unit  1000  is mounted to a picatinny rail  1080  of a firearm of  FIG. 20 .  FIG. 23  is front top left perspective view of the folding stacking unit  1000  attached to a vertical fore grip  1090 , with the stacking unit  1000  mounted to the firearm of  FIG. 21 . 
       FIG. 24  is side view of bipod vertical fore grip  1090  detached from the stacking unit  1000  that is mounted beneath the firearm  1200 . As previously described, the clamping grooves of the stacking unit  1000  can mateably slide about the picatinny type rails  1080  under the firearm  1200 , Alternatively, the stacking unit  1000  can be attached to the picatinny rails by removing the optional side plate  1006  (shown in  FIG. 20 ), by fasteners  1004  and positioning the remaining clamping groove about a picatinny rail and fastening the side plate  1006  back in place with fastener  1004 . 
       FIG. 25  is another side view of  FIG. 24  with the fore grip  1090  mounted to the stacking unit  1000 .  FIG. 25A  is an enlarged view of the fore grip  1090  mounted to stacking unit  1000  of  FIG. 25 , 
       FIG. 26  is another view of  FIGS. 24-25  with fore grip in folded position to the firearm.  FIG. 26A  is an enlarged view of the folded fore grip  1090  and mounting plate  1000  with firearm  1200  of  FIG. 26 . 
     Similar to the techniques for mounting the stacking unit  1000  to the firearm  1200 , the fore grip  1090  can be mounted by sliding the grooves on the top of the fore grip  1090  about the side rails  1024 ,  1026  on the sides of the lower plate member (pivot rail member)  1020 . Alternatively, the side plates on the top of the fore grip  1090  can be removed and the fore grip  1090  attached to the side rails of the pivot rail member  1020  similar to the technique described above. 
     Referring to  FIGS. 25 ,  25 A,  26  and  26 A, pivot rail member  1020  with fore grip  1090  can be held in a horizontal orientation by a frictional fit. Alternatively, a pivotal lock catch  1120  which is pivotally attached to an undersurface portion of top plate member  1010  to one side of the fore grip  1090  has a pivotal arm with a notch end  1022 . Folding up fore grip  1090  in the direction of arrow F causes pivotal lock catch  1120  to rotate up so that rounded tip edges about notch  1022  push back spring biases spring pin  1135  in set screw  1130  until pin  1135  extends and catches into notch  1022  resulting in the fore grip  1090  being locked in a horizontal position. Pulling down on the bottom of fore grip  1090  can cause the other tip edge of pivotal lock catch  1120  to push against pin  1135  allowing the fore grip  1090  to go back to a vertical position. 
     Light Embodiments 
       FIG. 27  is a side view of a foldable light/foldable fore grip light  1400  detached from a stacking unit  1000  that is mounted beneath a firearm  1200 .  FIG. 28  is another view of  FIG. 27  showing the light/fore grip  1400  with light  1410 , attached to the firearm mounted stacking unit  1000 , with light/fore grip  1400  with light  1410 , in folded position.  FIG. 29  is another view of  FIGS. 27-28  with light/fore grip  1400  with light  1410  in downward extended position, with the light  1410  being useable as a map light, or the light being used as a vertical fore grip. 
     Referring to  FIGS. 27-29 , the invention can have a novel light mounted to the stacking unit  1000 , so that the light can be used in either a folded position, or in a downwardly extending position. The light/fore grip  1400  with light  1410  can have an upper plate member assembly  1450  similar to dual inwardly facing grooves that exist on the top of the fore grip  1090  described above, with optional fastener  1455 , which can attach to the lower plate member  1120  similar to the previous embodiments above. 
     The folding unit can also allow the light to fold frontward, so that the light is turned on in the direction of where the firearm is pointed. Additionally, the folding unit can allow the light to face rearward behind the firearm. Additionally, the folding unit can allow the light to face sideways to the left and to the right of the firearm, as well. 
     Still furthermore, the invention can allow for both a vertical fore grip with a light built  1550  into the fore grip  1500 , so that it can have dual functions for use as a vertical fore grip and as light. The light can be useful for non firearm use, such as a map light to allow the operator to view maps, and the like, during dark conditions.  FIG. 30  shows a novel combined vertical fore grip  1500  with built in-light.  FIG. 31  is a side cross-sectional view of the interior of the fore grip light  1500  of  FIG. 30 . 
     Referring to  FIGS. 30-31  the fore grip  1500  can have a similar shape to the exterior surfaces of the fore grip  1090  previously described with an upper end  1505  being attachable to the lower plate member  1020  of stacking unit  1000  similar to the fore grip  1090  previously described. The inside  1550  of the fore grip  1500  can include components such as but not limited to batteries  1530  and a light source  1515 , such as a bulb, LED (light emitting diode), and the like, and lens  1510 . Cap  1520  can rotate to both turn on the light and allow the lens  1510  to extend beneath fore grip  1500 . Alternatively, side button  1590  can be depressed to active and deactivate light  1515 . 
     Although the invention mentions a plate, the invention can include different shapes, such as but not limited to oblong shapes, rectangular shapes, cylindrical shapes, and the like. 
     While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.