Abstract:
Foldable and flippable adapter devices, apparatus, systems and methods of attaching accessories to firearm rails. Accessories can include fore grips, and lights. Adapters can include a slidable thumb switch for locking a swinging plate with side rails to a main plate, and spring loaded detents for locking the swinging plate in substantially vertical orientations. A folding rail adapter can be substituted for the existing rail system on firearms to allow the rail to be directly attached to the firearm. A flipping rail adapter can have a pivotal lever which supports a folding rail in an open position. Springably biased detent pins allow the lever to lock open. Pushing the lever back will overcome the springs so that the pins can pass out of the detents allowing the folding rail to move to a folded position.

Description:
This invention is a continuation-in-part of U.S. patent application Ser. No. 12/986,374 filed Jan. 7, 2011, which is a divisional of U.S. patent application Ser. No. 12/856,340 filed Aug. 13, 2010, now U.S. Pat. No. 7,987,623, which is a continuation-in-part of U.S. patent application Ser. No. 12/700,887 filed Feb. 5, 2010, now U.S. Pat. No. 8,028,457, which is a divisional of U.S. patent application Ser. No. 11/934,392 filed Nov. 2, 2007, now U.S. Pat. No. 7,861,451, 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 using foldable and flippable accessory adapters or folding rail assemblies for allowing a firearm to be attached to various devices such as but not limited to fore grip/gun handle that can have bipod type legs or only a vertical extension, and or other 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 Keng; 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. 
     An eighth objective of the subject invention is to provide devices, apparatus, systems and methods of using a folding plate assembly for attaching to existing picatinny rails on a firearm, that can support accessories such as fore grips, lights, and the like. 
     An ninth objective of the subject invention is to provide devices, apparatus, systems and methods of substituting a folding rail assembly for the existing picatinny rails plate on firearms, where the folding rail plate assembly does not enlarge the existing picatinny rail plate used on firearms. 
     A tenth objective of the subject invention is to provide devices, apparatus, systems and methods of substituting a folding rail assembly for the existing picatinny rails plate on firearms, that uses less material and is less expensive than a folding plate adapter. 
     An eleventh objective of the subject invention is to provide devices, apparatus, systems and methods of using a flip attachment and adapter assembly for attaching to existing picatinny rails on a firearm, that can support accessories such as fore grips, lights, and the like. 
     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 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. 
     Another embodiment of the firearm adapter can include an adapter member having an upper side and a lower side, a clamp on the upper side of the adapter member for allowing the member to be clamped to picatinny rails located beneath a firearm, a swing plate pivotally attached to the lower side of the adapter member, the swing plate having picatinny side edges for supporting an accessory thereon, and a sliding switch for allowing the swing plate to be released from a horizontal locked position to be able to rotate to a substantially vertical position. 
     The sliding switch can include an angled raised surface for allowing a finger of a user to push against, and a spring for biasing the sliding switch to the locked position. The sliding switch can include a set screw for adjusting the biasing extension of the spring. 
     The adapter can include a catch on a free end of the swinging plate for catching onto a protruding end on the sliding switch, so that the swinging plate is held in the locked position, and a spring loaded latch for locking the swinging plate in the substantially vertical position. 
     The adapter can include both a first spring for biasing the sliding switch to the locked horizontal position, and a second spring for locking the swinging plate to the substantially vertical position. 
     The accessory supported by the adapter can be a vertical fore grip, a bipod, or a fore grip with collapsible bipod legs. Additionally, the accessory can include a light or laser source. 
     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, clamping upper sides of a top plate member about the picatinny rails, pivotally attaching one end of a bottom plate member to the top plate member, locking the bottom plate member into a folded horizontal position parallel to the top plate member by a sliding switch being moved in one direction, and releasing the bottom plate member to rotate to a substantially vertical position by moving the sliding switch in an opposite direction. 
     The method can include the steps of spring biasing the sliding switch toward the one position, and/or locking the bottom plate member to the substantially vertical position by a spring. 
     A folding rail for firearms can be a folding rail assembly that can be substituted for an existing picatinny rails on a firearm, The folding rail can include a plate shaped member having a first end, a second end, a first longitudinal picatinny rail along one side of the plate shaped member between the first end and the second end, and a second longitudinal picatinny rail along an opposite side of the plate shaped member between the first end and the second end, and a hinge for allowing a portion of both the first longitudinal picatinny rail and the second picatinny rail to pivot relative to the plate shaped member, from a horizontal position to a substantially vertical position, wherein the plate shaped member is attached to an undersurface of a firearm. 
     The folding rail can include a latch for locking the portion of both the first longitudinal picatinny rail and the second picatinny rail to be in the horizontal position relative to the plate shaped member, and mounting holes in the plate shaped member for allowing fasteners to attach the plate shaped member to the undersurface of the firearm. 
     The plate shaped member can include a forward end with picatinny rails on both sides, and a rearward end with picatinny rails on both sides, with a middle rail section between the forward end and the rearward end, the middle end being pivotally attached to one of the forward end or the rearward end. The pivotal middle rail section includes picatinny rails on both sides of the middle rail section. 
     Another embodiment can include a firearm flip adapter for mounting accessories thereon, which includes an adapter member having an upper side and a lower side, a clamp on the upper side of the adapter member for allowing the member to be clamped to picatinny rails located beneath a firearm, a swing plate pivotally attached to the lower side of the adapter member, the swing plate having picatinny side edges for supporting an accessory thereon, a pivoting lever for holding the swing plate in a substantially vertical open position, and a switch for allowing the swing plate to be released from a horizontal locked position to be able to rotate to the substantially vertical open position. The switch can be a pivoting switch having a free end protruding sideways from the adapter assembly for allowing a finger of a user to move the switch. The switch can have a spring for biasing the pivoting switch to the locked position. 
     The adapter can have a catch on a free end of the swinging plate for catching onto a protruding end on the pivoting switch, so that the swinging plate is held in the locked position. The pivoting lever can include a lock position for locking the swinging plate in the substantially vertical position. The lock can include a first detent surface on a side of the lever, and a first moveable detent pin forming the lock position by pressing an end of the detent pin into the detent surface on the side of the lever. The adapter can include a first spring for biasing the detent pin into the lock position. The adapter can include a second detent surface on another side of the lever, and a second moveable detent pin forming a second lock position with an end of the second detent pin pressed into the second detent surface on the another side of the lever. The adapter can include a first spring for biasing the first detent pin into the first lock position, and a second spring for biasing the second detent pin into the second lock position. 
     The adapter can include a longitudinal slot down the lower side of the adapter member, the longitudinal slot for allowing a portion of the lever to rest therein when the swinging plate is in the locked closed position. 
     The accessory can be a vertical fore grip. The accessory can be a bipod. The accessory can be a fore grip with collapsible bipod legs. 
     A 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, clamping upper sides of a top plate member about the picatinny rails, pivotally attaching one end of a bottom plate member to the top plate member, pivotally attaching a lever between the top plate member and the bottom plate member, folding the bottom plate member into a folded horizontal position parallel to the top plate member by pivoting the top plate member relative to the bottom plate member, and pivoting the lever between the top plate member and the bottom plate member, and locking the bottom plate member into a substantially vertical position by a switch, which allows for the bottom plate member to pivot relative to the top plate member, and allows for the lever to pivot between the bottom plate member and the top plate member. 
     The method can include the step of pressing a detent pin into a detent surface on a side of the lever to lock the bottom plate member into the substantially vertical position. The method can include the step of biasing the detent pin into the detent surface by a spring. The method can include the step of pressing a first detent pin into a first detent surface on a side of the lever to lock the bottom plate member into the substantially vertical position, and pressing a second detent pin into a second detent surface on another side of the lever to lock the bottom plate member into the substantially vertical position. The method can include the step of biasing the first detent pin into the first detent surface by a first spring, and biasing the second detent pin into the second detent surface by a second spring. 
     The method can include the steps of providing a longitudinal slot down the lower side of the adapter member, and resting a portion of the lever into the longitudinal slot when the swinging plate is in the locked closed position. 
     A flippable adapter for mounting accessories thereon, can include a top plate member having an upper side and a lower side, a clamp on the upper side of the top member for allowing the top member to be clamped to picatinny rails located beneath a firearm, a bottom swing plate pivotally attached to the lower side of the top member, the bottom swing plate having picatinny side edges for supporting an accessory thereon, and a pivoting lever attached between the top plate member and the bottom plate member, the pivoting lever having a locked open position for holding the bottom swing plate in a substantially vertical open position relative to the top plate, and the pivoting lever having a locked closed position for holding the bottom swing plate in a sandwiched orientation to the top plate member. 
     The invention can attach to rail systems, such as picatinny rails underneath or to the side or on top of firearms. 
     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 . 
         FIG. 32  is a front bottom perspective view of another embodiment of the folding stack adapter assembly with long clamp. 
         FIG. 33  is a rear bottom perspective view of the adapter assembly of  FIG. 32 . 
         FIG. 34  is a front top perspective view of the adapter assembly of  FIG. 32 . 
         FIG. 35  is a rear top perspective view of the adapter assembly of  FIG. 32 . 
         FIG. 36  is a top view of the folding stack adapter assembly of  FIG. 32 . 
         FIG. 37  is a side view of the folding stack adapter assembly of  FIG. 32 . 
         FIG. 38  is a bottom view of the adapter assembly of  FIG. 32 . 
         FIG. 39A  is a left view of the adapter assembly of  FIG. 32 . 
         FIG. 39B  is an enlarged view of a portion of the adapter assembly of  FIG. 39A  showing radial slot cut in clamping apex to relieve mechanical clamping stress. 
         FIG. 39C  is another radial slot cut in clamping apex to relieve mechanical clamping stress. 
         FIG. 40  is a right view of the adapter assembly of  FIG. 32 . 
         FIG. 41  is a front top perspective view of the adapter assembly of  FIG. 32  with a long clamp. 
         FIG. 42  is a front top perspective view of the adapter assembly of  FIG. 32  with exploded long clamp. 
         FIG. 43  is a front top perspective view of adapter assembly with two short clamps. 
         FIG. 44  is a front top perspective view of the adapter assembly of  FIG. 32  with exploded short clamps. 
         FIG. 45  is an exploded top front perspective view of the adapter assembly with long clamp. 
         FIG. 46  is an exploded top rear perspective view of the adapter assembly of  FIG. 45  with long clamp. 
         FIG. 47  is an exploded bottom front perspective view of the adapter assembly of  FIG. 45  with long clamp. 
         FIG. 48  is an exploded bottom rear perspective view of the adapter assembly of  FIG. 45  with long clamp. 
         FIG. 49  is an end view of the adapter assembly of  FIG. 45  with long clamp. 
         FIG. 49A  is a cross-sectional view of the adapter assembly of  FIG. 45  with pivot rail up. 
         FIG. 49B  is an enlarged view of the thumb slide of  FIG. 49A . 
         FIG. 49C  is an enlarged view of the detent latch of  FIG. 49B . 
         FIG. 50  is a side view of the adapter assembly. 
         FIG. 51  is a side view of the adapter assembly with swing plate down. 
         FIG. 51A  is a cross-section view of the adapter assembly of  FIG. 49A  with pivot rail down. 
         FIG. 51B  is another view of the thumb slide of  FIG. 49B  with pivot rail down. 
         FIG. 51C  is another view of the detent latch of  FIG. 49C  with pivot rail down. 
         FIG. 52  is a side view w/pivot rail down. 
         FIG. 53  is a bottom front perspective view of the adapter assembly of the preceding figures with picatinny rail and fore grip with collapsible bipod legs. 
         FIG. 54  is a bottom rear perspective view of the adapter assembly with picatinny rail and fore grip with collapsible bipod legs of  FIG. 53 . 
         FIG. 55  is a front top perspective view of the adapter assembly with picatinny rail and fore grip with collapsible bipod legs of  FIG. 53 . 
         FIG. 56  is a front rear perspective view of the adapter assembly with picatinny rail and fore grip with collapsible bipod legs of  FIG. 53 . 
         FIG. 57  shows the adapter assembly of the preceding figures locked to a gun&#39;s picatinny rail separated from fore grip with collapsible bipod legs. 
         FIG. 58  shows the adapter assembly locked to the gun&#39;s picatinny rail of  FIG. 57  for fore grip with collapsible legs. 
         FIG. 59  is another view of the adapter assembly swinging open on an unlatched pivot rail. 
         FIG. 60  is a bottom front perspective view of a folding rail assembly. 
         FIG. 61  is a bottom rear perspective view of the folding rail assembly of  FIG. 60  with pivot rail down. 
         FIG. 62  is a top rear perspective view of the folding rail assembly of  FIG. 61  with pivot rail down. 
         FIG. 63  is another top front perspective view of the folding rail assembly of  FIG. 62  with pivot rail down. 
         FIG. 64  is a top view of the folding rail assembly of  FIG. 60 . 
         FIG. 65  is a left view of the folding rail assembly of  FIG. 60 . 
         FIG. 66  is a front view of the folding rail assembly of  FIG. 60 . 
         FIG. 67  is a right view of the folding rail assembly of  FIG. 60 . 
         FIG. 68  is a bottom view of the folding rail assembly of  FIG. 60 . 
         FIG. 69  shows a folding rail assembly being used to replace stock picatinny rail supplied with a gun, and detached fore grip with collapsible bipod legs. 
         FIG. 70  is another view of  FIG. 69  with fore grip having collapsible bipod legs connected to a locked folding rail assembly on gun. 
         FIG. 71  is another view of  FIG. 70  with fore grip having collapsible bipod legs attached to the folding rail assembly swinging open on unlatched pivot rail. 
         FIG. 72  is a bottom front perspective view of flip attachment adapter assembly with the folding rail closed. 
         FIG. 73  is a bottom front perspective view of the assembly of  FIG. 72  with the folding rail open. 
         FIG. 74  is a bottom rear perspective view of the assembly of  FIG. 72  with the folding rail closed. 
         FIG. 75  is a bottom rear perspective view of the assembly of  FIG. 72  with the folding rail open. 
         FIG. 76  is a top rear perspective view of the assembly of  FIG. 72  with folding rail closed. 
         FIG. 77  is a top rear perspective view of the assembly of  FIG. 72  with folding rail open. 
         FIG. 78  is a top front perspective view of the assembly of  FIG. 72  with the folding rail closed. 
         FIG. 79  is a top front perspective view of the assembly of  FIG. 72  with folding rail open. 
         FIG. 80  is a bottom view of the assembly of  FIG. 72 . 
         FIG. 81  is a right side view of the assembly of  FIG. 72 . 
         FIG. 82  is a top view of the assembly of  FIG. 72 . 
         FIG. 83  is a left side view of the assembly of  FIG. 72 . 
         FIG. 84  is a rear view of the assembly of  FIG. 72 . 
         FIG. 85  is a front view of the assembly of  FIG. 72 . 
         FIG. 86A  is a cross-sectional view of the assembly of  FIG. 72  with the folding rail closed. 
         FIG. 86B  is another cross-sectional view of the assembly of  FIG. 86A  with the folding rail half opened. 
         FIG. 86C  is another cross-sectional view of the assembly of  FIG. 86A  with the folding rail fully opened. 
         FIG. 87  is a bottom rear perspective view with partial cross-sectional view of the assembly of  FIG. 72  with folding rail closed. 
         FIG. 88  is another view of  FIG. 87  with the folding rail is half open. 
         FIG. 89  is another view of the assembly of  FIG. 87  with the folding rail is fully open. 
         FIG. 90A  is a bottom right perspective view along arrow  90 Y of the assembly of  FIG. 89  with the folding rail sectioned on the center-line of the spring loaded detent pins. 
         FIG. 90B  is a bottom left perspective view along arrow  90 Y of the assembly of  FIG. 89  with the folding rail sectioned on the center-line of the spring loaded detent pins. 
         FIG. 91  is another bottom front perspective view of the assembly of  FIG. 72  with the folding rail cut-away to show how the down-latch engages the catch surface on the folding rail. 
         FIG. 92  is another view of the assembly of  FIG. 91  except the down-latch release lever has been pushed forward. This action disengages the down-latch from the folding rail allowing the rail to open. 
         FIG. 93  is a top perspective view of the assembly of  FIG. 72  with clamp and clamp screws exploded. 
         FIG. 94  is a top perspective exploded view of the assembly of  FIG. 72 . 
         FIG. 95  is a bottom perspective exploded view of the assembly of  FIG. 72 . 
         FIG. 96  is a perspective view of picatinny rail separate from the adapter assembly, and separated from fore-grip oriented for assembly. The picatinny rail would typically be attached to a rifle (not shown). 
         FIG. 97  is another perspective view of adapter assembly mounted to the picatinny rail in  FIG. 96  with the fore-grip oriented for mounting to the adapter assembly. 
         FIG. 98  is a perspective view of the picatinny rail with attached assembly, with the fore-grip mounted to the adapter assembly. 
         FIG. 99  is a side view of a closed adapter assembly with a fore-grip with the adapter assembly mounted to a picatinny rail underneath a rifle. 
         FIG. 100  is another view of  FIG. 99  with the adapter assembly opened. 
         FIG. 101  is a side view of a closed adapter assembly with an accessory light, with the adapter assembly mounted to a picatinny rail underneath a rifle. 
         FIG. 102  is another view of  FIG. 101  with the adapter assembly opened. 
         FIG. 103  is a perspective view of the adapter assembly of  FIG. 72  with an alternate down-latch release button switch. This actuator is a sliding button as opposed to the previously presented lever release. The latch is engaged in this view. 
         FIG. 104  is another view of  FIG. 103  except the button switch has been moved to the left and the latch is disengaged. 
         FIG. 105  is a side view of the adapter assembly of  FIG. 72  mounted to the picatinny rail of a rifle. A dimension is given showing the distance from the bottom of the rifle rail to the bottom of the rail underneath the adapter assembly. 
     
    
    
     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 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 
           1700  Adapter assembly with one long clamp. 
           1710  Adapter body. 
           1720 ) Swing plate. 
           1730  Pivot pin. 
           1740  Detent plate. 
           1750  Detent latch. 
           1760  Picatinny rail. 
           1770  Grip pod assembly. 
           1780  Adapter assembly with two short clamps. 
           1790  Gun. 
           1800  Folding rail assembly. 
           1810  Folding assembly swing plate. 
           1820  Thumb nut. 
           1830  Thumb slide. 
           1840  Plate latch. 
           1850  Long clamp. 
           1860  Set screw. 
           1870  Clamp screw. 
           1880  Short clamp A. 
           1890  Short clamp B. 
           1900  Radial stress relief slot. 
           1910  Slide spring. 
           1920  Detent spring. 
           1930  Folding rail body. 
           1940  Folding rail swing plate latch. 
       
    
       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 . 
     A list of components for additional embodiments will now be described.  1700 ) Adapter assembly with one long clamp. 
     
         
           1710  Adapter body. 
           1712  Front end 
           1713  Front horizontal slot 
           1715  Rear horizontal slot 
           1717  Longitudinal slot 
           1718  Rear end 
           1719  Cavity with mateable grooved interior walls 
           1720  Swing plate. 
           1722 . Side edges 
           1724  bottom of plate with raised flat ribs (four shown) 
           1725  hinge end 
           1726  top of plate with raised rounded ribs (two shown) 
           1727  groove in rounded surface of hinge end  1725   
           1728  outer ledge catch end 
           1730  Pivot pin. 
           1740  Detent plate. 
           1745  Screw type fasteners  1750  Detent latch. 
           1752  U-shaped slot 
           1758  Protruding end 
           1760  Picatinny rail. 
           1770  Grip pod assembly. 
           1780  Adapter assembly with two short clamps. 
           1790  Gun. 
           1800  Folding rail assembly. 
           1810  Folding assembly swing plate. 
           1815 . Hinge 
           1820  Thumb nuts. 
           1830  Thumb slide. 
           1835  Screw type fastener 
           1840  Plate latch. 
           1842  Raise side edges of plate latch 
           1844  Rear end of latch 
           1845 . Slot in latch 
           1848  Protruding end 
           1850  Long clamp. 
           1860  Set screw. 
           1870  Clamp screws. 
           1875  Threaded ends. 
           1880  Short clamp A. 
           1890  Short clamp B. 
           1900  Radial stress relief slot. 
           1910  Slide spring. 
           1920  Detent spring. 
           1930  Folding rail body. 
           1932 . Forward End 
           1933 . opening 
           1935 . Base 
           1937 . opening 
           1938  rearward end 
           1940  Folding rail swing plate latch. 
           1942 . Rotatable Knob 
           1945  Protruding edge
 
Adapter Assembly with One Long Clamp
 
       
    
       FIG. 32  is a front bottom perspective view of another embodiment of the folding stack adapter assembly  1700  with long clamp.  FIG. 33  is a rear bottom perspective view of the adapter assembly  1700  of  FIG. 32 .  FIG. 34  is a front top perspective view of the adapter assembly of  FIG. 32 .  FIG. 35  is a rear top perspective view of the adapter assembly  1700  of  FIG. 32 .  FIG. 36  is a top view of the folding stack adapter assembly  1700  of  FIG. 32 .  FIG. 37  is a side view of the folding stack adapter assembly  1700  of  FIG. 32 .  FIG. 38  is a bottom view of the adapter assembly  1700  of  FIG. 32 .  FIG. 39A  is a left view of the adapter assembly  1700  of  FIG. 32 .  FIG. 39B  is an enlarged view of a portion of the adapter assembly  1700  of  FIG. 39A  showing radial slot cut in clamping apex to relieve mechanical clamping stress.  FIG. 39C  is another radial slot cut in clamping apex to relieve mechanical clamping stress.  FIG. 40  is a right view of the adapter assembly  1700  of  FIG. 32 .  FIG. 41  is a front top perspective view of the adapter assembly  1700  of  FIG. 32  with a long clamp  1850 .  FIG. 42  is a front top perspective view of the adapter assembly  1700  of  FIG. 32  with exploded long clamp  1850 . 
       FIG. 45  is an exploded top front perspective view of the adapter assembly with long clamp.  FIG. 46  is an exploded top rear perspective view of the adapter assembly of  FIG. 45  with long clamp.  FIG. 47  is an exploded bottom front perspective view of the adapter assembly of  FIG. 45  with long clamp.  FIG. 48  is an exploded bottom rear perspective view of the adapter assembly of  FIG. 45  with long clamp  1850 .  FIG. 49  is an end view of the adapter assembly of  FIG. 45  with long clamp  1850 .  FIG. 49A  is a cross-sectional view of the adapter assembly of  FIG. 45  with pivot rail up. 
       FIG. 49B  is an enlarged view of the thumb slide of  FIG. 49A .  FIG. 49C  is an enlarged view of the detent latch of  FIG. 49B .  FIG. 50  is a side view of the adapter assembly.  FIG. 51  is a side view of the adapter assembly with swing plate down.  FIG. 51A  is a cross-section view of the adapter assembly of  FIG. 49A  with pivot rail down.  FIG. 51B  is another view of the thumb slide of  FIG. 49B  with pivot rail down.  FIG. 51C  is another view of the detent latch of  FIG. 49C  with pivot rail plate  1720  down.  FIG. 52  is a side view w/pivot rail plate  1720  down. 
     Referring to  FIGS. 32-52 , an adapter assembly with one long clamp  1700  can include a rectangular adapter body  1710  having a plate type configuration. Located on the bottom the adapter assembly body  1710  can be swing plate  1720  with side edges  1722  similar to the edges of a picatinny rails (shown as  1760  in  FIG. 53 ) that are often attached underneath of a weapon. The pivoting plate  1720  can be located between the front end  1712  and rear end  1718  of the adapter body  1710 . The plate  1720  can have a bottom side  1724  with raised flat ribs, and an upper top side  1726  with raised rounded ribs. One end  1725  of the plate  1720  can be pivotally attached by a pivot pin  1730  to a front end  1712  of the adapter body  1710  (see  FIG. 51A ). 
     Detent Plate in Front End 
     In the front end  1712  of the adapter body  1710  can be detente plate  1740  which holds a detent spring  1920  on inner side. See for example,  FIGS. 32 ,  34 ,  39 A,  41 - 45 ,  47 ,  48 ,  49 C,  51 C. The detent plate  1740  can be a fixably attached to the front end  1712  of the adapter body  1710  by screw type fasteners  1745 . The detent spring  1920  pushes into a U-shaped slot  1752  of the detent latch  1750 . The opposite protruding end  1758  is biased toward and against the pivot hinge  1725 . The rounded exterior surface of the pivot hinge  1725  allows for the rail plate  1720  to easily rotate downward until the protruding end  1758  locks into groove  1727  in the exterior surface  1725  of the swing plate  1720  so that the pivoting plate  1720  is locked in a substantially vertical orientation relative to the adapter body  1710 . (See  FIGS. 49A ,  49 C,  51 A,  51 C). 
     To rotate the pivoting plate  1720  back to a horizontal position, the user can press against the pivoting plate, often by grabbing the accessory clamped to the plate such as the fore grip to overcome the spring tension  1920  of the detent plate  1740 . 
     Thumb Slide in Rear End 
     In the rear end  1718  of the adapter body  1710  can be a thumb slide  1830 . See for, example,  FIGS. 32 ,  33 ,  35 ,  37 ,  38 ,  40 ,  45 ,  46 ,  47 ,  48 . The thumb slide  1830  can have a raised angled surface and be attached to a slot  1845  in plate latch  1840  by a screw type fastener  1835  (See  FIGS. 45 ,  47 ,  48 ). The plate latch  1840  can have raised side edges  1842  form a dovetail shape that allows the plate latch  1840  to slide within a matching grooves inside of dovetail shaped cavity  1719  in rear end  1718  of the adapter body  1710 . A longitudinal slot  1717  along the longitudinal axis of the rear end  1718  allows for the thumb slide  1830  to slide relative to the rear end  1718 . (See  FIGS. 45 ,  47 ,  48 ). 
     The freely moving protruding end  1848  of the plate latch  1840  when pushed by the thumb slide  1830  in the direction of arrow X 1  can latch onto and catch the outer ledge catch step-shaped end  1728  of the freely moving end of the swing plate  1720 . The upper surface of the protruding end  1848  can be sloped at an angle so as to lift against the catch step-shaped end  1728  of the swing plate  1720 . The spring  1910  pushes the sloped surface of protruding end  1848  so that it takes up any play between itself and the catch step-shaped end  1728 . This play can exist based due to manufacturing tolerances and/or regular wear of these parts. See for example,  FIGS. 49A ,  49 B,  51 A,  51 B. 
     The rear end  1844  of the plate latch  1840  can push against a slide spring  1910  and the length adjustable set screw  1860  so that the protruding end  1848  of the plate latch  1840  is being pushed in the direction of arrow X 1 . The spring is sandwiched between the set screw  1860  and the rear end  1844  of the plate latch  1840 . By not fully seating the screw  1860  against the spring  1910 , the tension of the spring  1910  can be adjusted. Tightening the length adjustable set screw  1860  can further lock the protruding end  1848  of the plate latch against the outer ledge catch end  1728  of the swing plate  1720 . Loosening the set screw  1860  can allow for the thumb slide  1830  to more easily slide in place. The user can release the swing plate  1720  from a horizontal position and rotate in the direction of arrow R, by pushing the thumb slide  1830  in the direction of arrow X 2 , shown in  FIGS. 51 ,  51 A,  51 B,  52 . 
     A pair of clamp screws  1870  can pass through horizontal slots ( 1713  in the front end, and horizontal slot  1715  in the rear end  1718  of the adapter body  1710 . See for example,  FIGS. 39A ,  39 B,  39 C,  40 ,  45 - 48 . The threaded ends  1875  of the clamp screws  1870  are held against the long clamp  1850  by respective thumb nuts  1820 . A radial stress relief slot  1900  can be formed between the long clamp  1850  side and the opposite side of the adapter body  1710 . The radial stress relief slot  1900  has interior facing groove side walls that allow for the adapter assembly to wrapped about picatinny rails underneath of a weapon. A user can loosen the thumb nuts  1820  to allow the adapter assembly  1700  to slide about the picatinny rails  1760  underneath a weapon  1790 , such as a gun. 
       FIG. 53  is a bottom front perspective view of the adapter assembly  1700  of the preceding figures with picatinny rail  1760  and fore grip  1770  with collapsible bipod legs. Such a fore grip with collapsible bipod legs can include ones such as those shown and described in U.S. Pat. Nos. D566,219; 7,111,424; 7,409,791; and 7,490,429 to the same assignees of the subject invention, and which are all incorporated by reference. 
       FIG. 54  is a bottom rear perspective view of the adapter assembly  1700  attached to a picatinny rail  1760 , where the adapter assembly  1700  is attached to a fore grip  1770  with collapsible bipod legs of  FIG. 53 .  FIG. 55  is a front top perspective view of the adapter assembly  1700  with picatinny rail  1760  attached to a fore grip  1770  with collapsible bipod legs of  FIG. 53 .  FIG. 56  is a front rear perspective view of the adapter assembly  1700  attached to picatinny rails  1760 , with the adapter assembly  1700  attached to the upper end of a fore grip  1770  with collapsible bipod legs of  FIG. 53 .  FIG. 57  shows the adapter assembly  1700  of the preceding figures locked to a gun&#39;s picatinny rail  1760  separated from the fore grip  1770  with collapsible bipod legs.  FIG. 58  shows the adapter assembly  1700  locked to the gun&#39;s picatinny rail  1760  of  FIG. 57  with the adapter assembly  1700  attached to the fore grip  1770  with collapsible legs.  FIG. 59  is another view of the adapter assembly  1700  with swing plate  1720  swinging open to an unlatched position. 
     Adapter Assembly with Two Short Clamps 
       FIG. 43  is a front top perspective view of adapter assembly  1780  with two short clamps  1880 ,  1890 .  FIG. 44  is a front top perspective view of the adapter assembly  1780  of  FIG. 32  with exploded short clamps  1880 ,  1890 . Unlike the previous embodiment, the adapter assembly  1780  has two short clamps  1880 ,  1890  instead of long clamp  1850 . Other than the short clamps  1880 ,  1890 , this embodiment functions similarly to the previous embodiment with long clamp  1850 . A radial stress relief slot  1900  is formed between the pair of short clamps  1880 ,  1890  and opposite side of the adapter body  1710 . The two clamps  1880 ,  1990  together have less weight and less material and be less costly than a single long clamp  1850 . Reducing weight of the invention can be desirable in the field where soldiers desire the least amount of weight for their equipment. The single long clamp  1850  can be more stable when attaching about picatinny rails underneath of a firearm. 
     Folding Rail Assembly 
       FIG. 60  is a bottom front perspective view of a folding rail assembly  1800 .  FIG. 61  is a bottom rear perspective view of the folding rail assembly  1800  of  FIG. 60  with pivot rail  1810  down.  FIG. 62  is a top rear perspective view of the folding rail assembly  1800  of  FIG. 61  with pivot rail  1810  down.  FIG. 63  is another top front perspective view of the folding rail assembly  1800  of  FIG. 62  with pivot rail  1810  down.  FIG. 64  is a top view of the folding rail assembly  1800  of  FIG. 60 .  FIG. 65  is a left view of the folding rail assembly  1800  of  FIG. 60 .  FIG. 66  is a front view of the folding rail assembly  1800  of  FIG. 60 .  FIG. 67  is a right view of the folding rail assembly  1800  of  FIG. 60 .  FIG. 68  is a bottom view of the folding rail assembly  1800  of  FIG. 60 . 
     Referring to  FIGS. 60-68 , the folding rail assembly  1800  includes a folding rail body  1930  having a generally planar plate configuration with a forward end  1932  and a rearward end  1938 , each having openings  1933 ,  1937  for allowing fasteners such as screws and bolts to attach the assembly  1800  to an undersurface of a weapon. In a preferred embodiment both the forward end  1932  and the rearward end  1937  have picatinny type side rails on both sides. In the middle of the assembly  1800  between the forward end  1932  and the rearward end  1937  can be pivotal swing plate  1810  also having picatinny type rails on both sides. A hinge  1815  attaches on end of the swing plate  1810  to the forward end  1932 . A swing plate latch  1940  can be on the rearward end  1938  of the rail assembly  1800 . The latch  1940  can be rotatable by a raised knob  1942  that allows for an extended portion  1945  to be over the free end  1812  of the swing plate  1810 . 
     On the top of the rail assembly  1800  can be a longitudinal base  1935  having a generally flat surface for allowing the rail assembly to sit flush against the undersurface of a firearm. 
       FIG. 69  shows a folding rail assembly  1800  being used to replace stock picatinny rail that is often supplied with a gun  1790 , and detached forward grip  1770  with collapsible bipod legs.  FIG. 70  is another view of  FIG. 69  with forward grip having collapsible bipod legs connected to a locked folding rail assembly on gun  1790 .  FIG. 71  is another view of  FIG. 70  with forward grip  1770  having collapsible bipod legs attached to the folding rail assembly  1800  swinging open on an unlatched pivot rail. 
     The folding rail assembly  1800  can be a substitute for the picatinny rails that are often attached underneath of firearm. The folding rail assembly can be used underneath the gun or in other areas, such as but not limited to be attached to one side of the gun or on top of the gun. 
     The folding rail assembly  1800  has a lower profile than the folding stack embodiments that were previously described. The folding rail assembly  1800  would allow for accessories such as a fore grip to be located closer to the weapon, instead of being spaced away from the weapon. A problem with fore grips is that the lower end of a vertical fore grip can extend further than what is desired. For example the lower bottoms of fore grips have been known to catch on the ground, etc., and/or poke into the user. 
     The folding rail assembly  1800  is more ergonomic than a folding stack assembly since it does not lengthen the overall length of a fore grip that can be attached thereon. 
     The folding rail assembly  1800  would be similar in weight to an existing picatinny rail system The folding rail assembly  1800  would have substantially less weight and use less material and be less expensive than the folding stack embodiments. 
     Similar to the previous embodiments, the folding rail can be modified to lock in both the horizontal and vertical positions, using features similar to that of the previous embodiments. 
     Flip Attachment Adapter Assembly 
     
         
           2000  Grip Flip assembly. 
           2001  Folding picatinny rail. 
           2002  Main body. 
           2002 A. Head portion of main body 
           2003  Picatinny Clamp edges. 
           2004  Down-latch release lever. 
           2005  Latch lever pivot pin. 
           2006  Detent pin retaining screw. 
           2007  Folding rail pivot pin. 
           2008  Clamp screw. 
           2009  Down-latch. 
           2010  Down-latch cover plate. 
           2011  Down-latch catch surface. 
           2012  Picatinny clamping feature on main body. 
           2013  T-slot captures lock lever guide pin (not shown). 
           2014  Lock lever. Holds folding rail in the up position. 
           2015  Lugs on the main body index the Grip Flip to the picatinny rail onto which the assembly is mounted. 
           2016  Rubber bumper. 
           2017  Down-latch adjustment screws. 
           2018  Cover plate mount screws. 
           2019  Lock lever guide pin. 
           2020  Lock lever detent. 
           2021  Detent pin. 
           2022  Detent pin spring. 
           2023  Nesting slot for lock lever. 
           2024  Down-latch spring. 
           2025  Down-latch adjustment screw. 
           2026  Lock lever pivot pin. 
           2027  Rubber O-ring. 
           2028  Picatinny rail mounted on firearm, such as a rifle 
           2029  Fore-grip. 
           2030  Firearm such as rifle 
           2031  Accessory light. 
           2032  Flip Adapter assembly shown with alternate latch release slider button. 
           2033  Latch release slider button. 
           2034  Down latch cavity. 
       
    
       FIG. 72  is a bottom front perspective view of flip attachment adapter assembly  2000  with the folding rail  2001  closed.  FIG. 73  is a bottom front perspective view of the assembly  2000  of  FIG. 72  with the folding rail  2001  open.  FIG. 74  is a bottom rear perspective view of the assembly  2000  of  FIG. 72  with the folding rail  2001  closed.  FIG. 75  is a bottom rear perspective view of the assembly  2000  of  FIG. 72  with the folding rail  2001  open.  FIG. 76  is a top rear perspective view of the assembly  2000  of  FIG. 72  with folding rail  2001  closed.  FIG. 77  is a top rear perspective view of the assembly  2000  of  FIG. 72  with folding rail  2001  open.  FIG. 78  is a top front perspective view of the assembly  2000  of  FIG. 72  with the folding rail  2001  closed.  FIG. 79  is a top front perspective view of the assembly  2000  of  FIG. 72  with folding rail  2001  open.  FIG. 80  is a bottom view of the assembly  2000  of  FIG. 72 .  FIG. 81  is a right side view of the assembly  2000  of  FIG. 72 .  FIG. 82  is a top view of the assembly  2000  of  FIG. 72 .  FIG. 83  is a left side view of the assembly  2000  of  FIG. 72 .  FIG. 84  is a rear view of the assembly of  FIG. 72 .  FIG. 85  is a front view of the assembly  2000  of  FIG. 72 . 
     Referring to  FIGS. 72-85 , the flip assembly  2000  includes folding rail  2001  having picatinny rail lower surface that can foldably attached to a main body  2002  by a folding rail pivot pin  2007 . The main body  2002  can have a clamp  2003  with picatinny clamping feature edges  2012  that can clamp about picatinny rails on a firearm. At least one clamp edge can be moveable by clamp screw(s)  2008 . A pivotal lock lever  2014  can hold the folding rail  2001  the functionality of which will be described later, in the up position. A rubber bumper  2016  on an inner surface of the main body  2002  can function as a vibration isolator when the folding rail  2001  is moved into a closed position. 
     A down latch release lever (switch)  2004  can be pivotally attached to a head portion  202 A of the main body  2002  by a latch lever pin  2005 . A down latch cover plate  2010  attached to the head portion  202 A by mount screws  2018  covers a rear end of the assembly  2000 . Pivoting the switch  2004  from one side to another can move the down latch  2009  into the head portion  202 A of the main body  2002  compressing spring  2024 . Releasing the latch switch  2004  decompresses spring  2024  which pushs the down latch  2009  into a down latch catch surface (slot)  2010  in the free end of the folding rail  2001 . Lugs  2015  on the main body  2002  can index the assembly  2000  to the picatinny rail on which the assembly  2000  can be mounted. 
     The down-latch adjustment screws  2017  provide an adjustable down stop for the folding rail  2001 . Should there be manufacturing variances in any of the down-latch components, there might be space between the down-latch  2009  and the down-latch catch surface  2011  when the folding rail  2001  is in the latched position. Any space between these components would cause undesirable looseness and noise in the assembly  2000 . The down-latch adjustment screws  2017  can be adjusted to move the down-latch catch surface  2011  closer to the down-latch  2009  removing any space and facilitating a tight fit. 
       FIG. 86A  is a cross-sectional view of the assembly  2000  of  FIG. 72  with the folding rail  2001  closed. Down latch  2009  is shown engaged to folding rail  2001 . Lock lever  2014  is shown in nesting slot  2023  of the main body  2002 . The spring loaded detent pin  2021  location is shown in all section views ( FIGS. 86A-86C ) so that the path of the pin  2021  into the detent  2020  can be seen as the folding rail  2001  is opened. 
       FIG. 86B  is another cross-sectional view of the assembly  2000  of  FIG. 86A  with the folding rail  2001  half opened. As the rail  2001  is opened the lock lever guide pin  2019  slides in the rail T-slot  2013 .  FIG. 86C  is another cross-sectional view of the assembly  2000  of  FIG. 86A  with the folding rail  2001  fully opened. The spring loaded detent pin(s)  2021  biased by spring(s)  2022  (shown in  FIG. 87 ) has found the detent  2020  and locked the rail  2001  in the open position. 
       FIG. 87  is a bottom rear perspective view with partial cross-sectional view of the assembly  2000  of  FIG. 72  with folding rail  2001  closed. In this view, the folding rail  2001  is cut-away to show how the lock lever  2014  is oriented to the spring ( 2022 ) loaded detent pin  2021 . The tip of the spring ( 2022 ) loaded detent pin  2021  can be seen resting against the side of the lock lever  2014 . The detent pin  2021  is under spring  2022  pressure and will drop into the lock lever detent  2020  (not shown) when the two are aligned (as shown in  FIG. 89 ). 
     In one embodiment there can be two detents  2020  and two spring ( 2022 ) loaded detent pins  2021 , one on either side of the lock lever  2014 . Only the facing detent pin  2021  can be seen in these views.  FIG. 87  shows how the lock lever guide pin  2019  follows the T-slot  2013  in the folding rail  2001 . 
       FIG. 88  is another view of  FIG. 87  with the folding rail  2001  is half open. The detent pin  2021  can be seen sliding along the lock lever  2014  and moving toward the lock to lever detent  2020 . The lock lever guide pin  2021  can be seen sliding down the T-slot  2013  in the folding rail  2001 . 
       FIG. 89  is another view of the assembly  2000  of  FIG. 87  with the folding rail  2001  fully open. The spring ( 2022 ) loaded detent pin  2021  has found the lock lever detent  2020  and has locked the lever  2014  in position. The lever  2014  therefore locks the folding rail  2001  in position. The lock lever guide pin  2019  can be seen at the extreme end of the T-slot  2013 . 
       FIG. 90A  is a bottom right perspective view along arrow  90 Y of the assembly  2000  of  FIG. 89  with the folding rail  2001  sectioned on the center-line of the spring loaded detent pins  2021 .  FIG. 90B  is a bottom left perspective view along arrow  90 Y of the assembly  2000  of  FIG. 89  with the folding rail  2001  sectioned on the center-line of the spring loaded detent pins  2021 . These two section views show the two inwardly biased detent pins  2021  as well as give another perspective on the previously shown and described lock lever guide pin  2019 . The inward spring biasing ( 2022 ) of the detent pins  2021  can be controlled by the adjustable depth of each detent pin retaining screw  2006 . 
       FIG. 91  is another bottom front perspective view of the assembly  2000  of  FIG. 72  with the folding rail  2001  cut-away to show how the down-latch  2009  engages the catch surface  2011  on the folding rail  2001 .  FIG. 92  is another view of the assembly  2000  of  FIG. 91  with the exception that the down-latch release lever  2004  has been pushed forward. This action disengages the down-latch  2009  from the folding rail  2001  allowing the rail  2001  to open. 
       FIG. 93  is a top perspective view of the assembly  2000  of  FIG. 72  with moveable clamp  2003  and clamp screws  2008  exploded.  FIG. 94  is a top perspective exploded view of the assembly  2000  of  FIG. 72 .  FIG. 95  is a bottom perspective exploded view of the assembly  2000  of  FIG. 72 . The lock lever  2014  is supported and pivotally attached to the main body the lock lever pivot pin  2025 . An O-ring  2027 , such as a rubber O-ring allows for smooth and frictionless rotation of the folding rail  2001  pivoting portions relative to the main body pivoting portions. 
     The down-latch adjustment screw  2025  threads into the down-latch  2009  and provides an adjustment for how far the down-latch  2009  can slide into down latch cavity  2034  before it bottoms and can go no further. This controls how far the front end of the down-latch  2009  protrudes from the opposite end of the cavity  2034  providing further latch adjustment over and above the down-latch adjustment screws  2017 . The down-latch spring  2024  spring loads the down latch  2009  insuring that the latch will engage with the down-latch catch surface  2011  of the folding rail  2001  when it is in the latch position. The down-latch  2009 , and spring  2024  are held in place by down-latch cover plate  2010 . The down-latch cover plate  2010  is affixed to the main body  2002  using cover plate mounting screws  2018 . 
       FIG. 96  is a perspective view of picatinny rail  2028  separate from the adapter assembly  2000 , and separated from fore-grip  2029  oriented for assembly. The picatinny rail  2028  would typically be attached to a firearm, such as a rifle not shown.  FIG. 97  is another perspective view of adapter assembly  2000  mounted to the picatinny rail  2028  in  FIG. 96  with the fore-grip  2029  oriented for mounting to the adapter assembly  2000 .  FIG. 98  is a perspective view of the picatinny rail  2028  with attached assembly  2000 , and with the fore-grip  2029  mounted to the adapter assembly  2000 . 
       FIG. 99  is a side view of a closed adapter assembly  2000  with a fore-grip  2029  attached adapter assembly  2000  mounted to a picatinny rail  2028  underneath a firearm  2030  such as but not limited to a rifle.  FIG. 100  is another view of  FIG. 99  with the adapter assembly  2000  opened. 
       FIG. 101  is a side view of a closed adapter assembly  2000  with an accessory light  2031 , with the adapter assembly  2000  mounted to a picatinny rail  2028  underneath the firearm  2030 .  FIG. 102  is another view of accessory light  2031  attached to the adapter assembly  2000  mounted firearm  2030  of  FIG. 101  with the adapter assembly  2000  opened. 
       FIG. 103  is a perspective view  2032  of the adapter assembly  2000  of  FIG. 72  with an alternate slide down-latch release button switch  2033 , which can operate as the those described and shown in previous embodiments of the invention. This actuator  2033  can be a sliding button as opposed to the previously described lever release  2004 . The switch is shown engaged in  FIG. 103 .  FIG. 104  is another view  2032  of  FIG. 103  except the button switch  2033  has been moved to the left and the latch is disengaged. 
       FIG. 105  is a side view of the adapter assembly  2000  of  FIG. 72  mounted to the picatinny rail  2028  of a firearm such as a rifle. In a preferred embodiment, the novel flip adapter  2000  will only add a depth of less than approximately one inch, and preferably as short in height to be 0.67 inches. This dimension shows the distance from the bottom of the firearm rail  2028  to the bottom of the rail underneath the adapter assembly  2000 . 
     Although the invention mentions a plate and shows some rectangular configurations, the invention can include different shapes, such as but not limited to oblong shapes, rectangular shapes, cylindrical shapes, and the like. 
     Although the invention is shown as being attached to rails underneath firearms, the invention can also be attached to rails on both of the sides of firearm, and/or on top of a firearm. 
     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.