Abstract:
The present invention relates to adaptable leg supports for bipod assemblies and more specifically to an adaptable leg support assembly that is pivotable with respect to the legs of the bipod to maintain complete contact with the supporting surface as the weapon is rotated, removable to allow the adaptable leg support assembly to be sued with multiple bipod assemblies, and adaptable for use on different surfaces by changing the foot portion of the adaptable leg support assembly that actually contacts the supporting surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/950,893, filed Jul. 20, 2007, which is hereby incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to bipods and monopods for use with rifles and other weapons, and more specifically to the supports at the end of the bipod legs that are in contact with the surface providing support for the weapon. 
     2. General Background of the Invention 
     Bipod supports have long been used in connection with the rifles and other weapons, hereinafter referred to collectively as rifles. Such devices are generally clamped or bolted to the weapon&#39;s barrel or connected to a picatinny rail. The legs for such bipods can be either fixed in position to support the weapon or, as is more commonly the case, are spring-loaded and retractable to allow the legs to be extended to the desired length to support a rifle at the desired elevation and swiftly and securely retracted for movement from location to location. Such a spring-loaded leg typically comprises an internal spring that extends from the upper portion of the leg, near where the bipod assembly attaches to the weapon, to the lower portion of the leg, at a point close to the end of the leg that is in contact with the surface supporting the weapon. 
     The internal spring is typically connected to the lower portion of the leg using a pin that has a diameter of one-eighth of an inch that extends through the leg and protrudes on both sides of the leg. To prevent this pin from snagging on the user&#39;s clothing or other objects, bipod manufacturers typically place this pin close enough to the end of the leg that the rubber boot on the end of the leg extends far enough up the leg to cover the ends of the pin, which also has the effect of holding the rubber boot in place. This rubber boot also typically provides the sole point of contact between the leg and the supporting surface. 
     This, however, creates numerous problems that result in decreased accuracy from the weapon when using such typical rubber boots. If the boots are rounded, a similar amount of contact is provided throughout the normal range that the weapon may be pivoted, but the contact surface is generally less than sufficient to effectively “load up” the weapon on a hard surface, resulting in the weapon hopping after a shot. (Loading up involves the shooter leaning forward with his shoulder against the weapon&#39;s stock to increase the pressure on the bipod to keep the weapon in place.) This results in the shooter having to reset after each shot. Such rounded over rubber boots also pose a problem on soft ground because the act of loading up the weapon will tend to drive the ends of the legs into the ground. 
     Other known designs use disk- or claw-shaped feet, ostensibly to provide greater contact with the ground. Since these known designs do not have the capability to pivot, the advantage of having an ostensibly larger contact area is lost unless the weapon is being used on perfectly flat ground at an elevation parallel to the ground. Thus, if the shooter has to tilt the weapon relative to the ground, a portion of the feet are lifted off of the ground, thereby reducing the amount of contact the feet have with the supporting surface. 
     Yet another problem with known bipod designs is that the feet are not removable. This results in users needing to carry multiple bipods for different surfaces to ensure that they have a bipod that will provide them with the accuracy they need under different circumstances—a luxury that many shooters, especially those in military and police swift response units, simply do not have. Alternatively, a user could carry a single bipod with generic feet, such as the rounded rubber boots described above, that allows the bipod to be use in a variety of conditions but at a less than optimal level of accuracy. 
     SUMMARY OF THE INVENTION 
     The present invention relates to adaptable leg supports for bipod for rifles that pivot to allow the leg support to maintain optimum contact with the surface, even on uneven ground, allowing the user to “load up” the weapon in a variety of circumstances. The adaptable leg supports are additionally interchangeable, allowing the user to carry a variety of adaptable leg supports to adapt a single bipod to a variety of conditions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following figures, wherein like reference numerals denote like elements and wherein: 
       FIG.  1 —Illustration of an embodiment of the invention wherein the adaptable leg support is attached to the leg of a bipod. 
       FIG.  2 A—Illustration of an embodiment of the invention wherein the adaptable leg support is detached from the leg of a bipod. 
       FIG.  2 B—Illustration of the embodiment shown in  FIG. 2B  wherein the adaptable leg support is attached to the leg of a bipod. 
       FIG.  3 —Exploded view of an embodiment of the invention. 
       FIG.  4 —Illustration of the embodiment shown in  FIG. 2A  wherein the adaptable leg support is attached to the leg of a bipod. 
       FIG.  5 —Illustration of an embodiment of the adapter portion of the adaptable leg support. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first embodiment of adaptable leg support assembly  10 . Adaptable leg support assembly  10  is comprised of adapter  22  and claw foot  50 . Adapter  22  comprises leg-receiving portion  24  and foot-receiving portion  26 . Adapter  22  is preferably machined from T6 aluminum although it can be formed from any substantially rigid material capable of having the requisite features machined into it or capable of being formed into the requisite shape by molding, die-casting, or other methods of forming. 
     Referring to  FIG. 3 , leg-receiving portion  24  of adapter  22  defines blind bore  28  and keyways  32  and  34 . Spring  30  is retained in blind bore  28  using an epoxy adhesive to adhere spring  30  to the bottom of blind bore  28 . Blind bore  28  has a diameter greater, preferably no more than one-sixteenth of an inch greater, than the diameter of leg L. Spring  30  preferably has a diameter equal to the diameter of leg L such that it exerts force against the bottom of leg L when leg L is inserted into blind bore  28 . Keyways  32  and  34  are J-shaped channels defined in the sidewall of blind bore  28  of the leg-receiving portion  24  of adapter  22 . Keyways  32  and  34  have a width just greater than the diameter of pin P (shown in  FIGS. 2 &amp; 4 ), thereby allowing pin P to traverse keyways  32  and  34 . The opening in keyways  32  and  34  are diametrically opposed to allow opposing end portions of pin P on leg L to simultaneously traverse keyways  32  and  34 . 
     Referring to  FIG. 2A , the lower portion of a typical bipod leg L (with the standard rubber boot removed) is illustrated. Leg L typically contains internal spring S that extends from pin P located at the lower end of each leg L to hinge bolts (not shown) at the upper end of each leg L. Leg L typically has a diameter of three-eighths of an inch and the pin P typically has a length of seven-eighths of an inch and a diameter of one-eighth of an inch. Of course these measurements can vary depending on the application for which the bipod is designed. The ends of pin P that extend beyond the outer surface of leg L provide the point of removable attachment for adapter  22 . 
     Referring to  FIGS. 2A and 2B , adapter  22  is connected to leg L by aligning the opening in keyway  32  and the opening in keyway  34  with the opposing end portions of pin P on leg L. Leg L is then inserted into blind bore  28  with sufficient force to compress spring  30  until the opposing end portions of pin P reach the bottom portion of the J-shape of keyways  32  and  34 . Adaptable leg support assembly  10  is then rotated until the opposing end portions of pin P reach the closed end portion of J-shaped keyways  32  and  34 . The force is then removed from leg L and the opposing force of spring  30  causes leg L to move slightly out of blind bore  28  until the end portions of pin P engage the closed end portion of keyways  32  and  34 . 
     Referring again to  FIG. 1 , claw foot  50  is attached to slotted portion  26  of adapter  22  via bracket  40 . Bracket  40  has an angle α that is equal to the angle that leg L makes with the barrel of the rifle. Bracket  40  is connected to claw foot  50  using a pair of three-sixteenth inch diameter rivets  41 . In alternative embodiments, a single rivet  41  or plurality of rivets  41  greater than two can be used to connect bracket  40  to claw foot  50  or one or more bolts and nuts (not shown) can be used. Bracket  40  is sized to slide into slot  42  defined by slotted portion  26  of adapter  22 . In one embodiment, the end portion of slot portion  26  of adapter  22  defines a pair of aligned apertures  44  located to align with aperture  46  in bracket  40  when bracket  40  is inserted into slot  42 . Bracket  40  is then pivotally connected to adapter  22  using threaded pivot pin  70  and nut  72  (best seen in  FIG. 3 ). The pivotal connection allows claw foot  50  to remain fully in contact with in contact with the supporting surface as the rifle is rotated through a range of angles to the supporting surface as the shooter aims the rifle. Thus, the shooter is allowed to load up the rifle more effectively because the complete contact of the feet with the ground allows the shooter to apply greater pressure to the rifle&#39;s shoulder rest without causing the feet slide. 
     In certain embodiments, washers (not shown) may be inserted between the internal walls of slot  42  and the adjacent surfaces of bracket  40  or rub sleeve  43  (best seen in  FIG. 3 ) surrounding a portion of bracket  40  adjacent to aperture  46  can be used to facilitate the rotation of bracket  40  relative to adapter  22 . (In  FIG. 3 , the rub sleeve is shown surrounding the portion of interconnection tab  102  of ski foot  100  that corresponds to the portion of bracket  40  that defines aperture  46  when claw foot  50  is connected to adapter  22 .) In certain embodiments the washers or rub sleeve  43  are formed from plastic, and in a certain embodiment rub sleeve  43  is formed from a polyacetal such as Delrin®. 
     Each claw  51  of claw foot  50  extends radially away from the center of claw foot  50  and is approximately equally spaced from adjacent claws  51 . Each claw  51  terminates in a point  52  that is turned down from upper surface  53  of claw foot  50 . 
     The embodiment illustrated in  FIGS. 2-4  includes ski foot  100 . Ski foot  100  is preferably formed from a single piece of metal or other relatively rigid material and comprises two portions: interconnection tab  102  and supporting portion  104 . Interconnection tab  102  forms an angle α with supporting portion  104  that is equal to the angle that leg L makes with the barrel of the rifle such that bottom surface  106  of supporting portion  104  is parallel to the barrel of the weapon when the bipods legs are deployed. Ski foot  100  has a thickness that is complementary to slot  42  defined by slotted portion  26  of adapter  22 , and interconnection tab  102  defines aperture  108  that allows ski foot  100  to be pivotally connected to adapter  22  in the same manner as bracket  40  of claw foot  50 . The pivotal connection allows supporting portion  104  of ski foot  100  to remain fully in contact with in contact with the supporting surface as the rifle is rotated through a range of angles to the supporting surface as the shooter aims the rifle. Thus, the shooter is allowed to load up the rifle more effectively because the complete contact of the feet with the ground allows the shooter to apply greater pressure to the rifle&#39;s shoulder rest without causing the feet slide. 
     As best seen in  FIG. 3 , threaded pivot pin comprises head end portion  74 , having a diameter greater than the diameter of aligned apertures  44  in adapter  22 ; opposing threaded end portion  78 ; and cylindrical portion  76 , having a smooth surface and a diameter slightly smaller than the diameter of aligned apertures  44  in adapter  22  and aperture  108  in interconnection tab  102  located intermediate head end portion  74  and opposing threaded end portion  78 . In the illustrated embodiment, rub sleeve  43  surrounds a portion of interconnection tab  102  adjacent to aperture  108  to facilitate the rotation of ski foot  100  relative to adapter  22 . 
     Supporting portion  104  of ski foot  100  further includes upstanding edges  110  and  112 . In the illustrated embodiment, edges  110  and  112  extend away from upper surface  114  of supporting portion  104  at an angle of approximately 135 degrees, but any angle between 90 and 180 degrees would work. These upstanding edges allow the wide, flat bottom surface  106  to slide easily of the top of the shooting surface rather than digging in. This characteristic is frequently desirable with automatic weapons to allow the user to quickly redirect fire without having to lift the weapon. 
     Ski foot  100  can be adapted for use in applications in which the user does not want the weapon to slide on the shooting surface by covering bottom surface  106  with non-slip boot  108 . Boot  108 , which can be any stretchable, non-slip material such as natural or synthetic rubber, is connected to ski foot  100  by inserting supporting portion  104  into boot  105 . This allows the user to load up the weapon when using it on a shooting bench or an urban surface such as a rooftop, a sidewalk, or a vehicle. 
     Illustrated in  FIG. 5  is an alternative embodiment of adapter  22 ′ that can accommodate bipods that have pins in the end portions of their legs as discussed above and bipods that do not have pins in the end portions of their legs. In this embodiment, keyways  24 ′ and  26 ′ have a straight shape rather than a J-shape and there is no spring contained in bore  28 . Also defined in adapter  22 ′ are one or more threaded apertures  27  for receiving set screws  25 . The leg of the bipod is inserted into bore  28  and the adapter is connected to the leg by tightening set screws  25  against the leg of the bipod. If the leg of the bipod has a pin located at its lower portion, the end portions of the pin can slide into keyways  24 ′ and  26 ′. 
     While the above describes several specific embodiments of the invention, those skilled in the art may appreciate that certain modifications may be made to the apparatus and methodology herein disclosed, without departing from the scope and spirit of the invention. Thus, it should be understood that the invention may be adapted to numerous rearrangements, modifications, and alterations and that all such are intended to be within the scope of the appended claims.