Patent Publication Number: US-10782084-B2

Title: Bipod for projectile weapons

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Application No. 62/554,457 filed 5 Sep. 2017. For purposes of the United States, this application claims the benefit under 35 U.S.C. § 119 of U.S. Application No. 62/554,457 filed 5 Sep. 2017 and entitled BIPOD FOR PROJECTILE WEAPONS which is hereby incorporated herein by reference for all purposes. 
    
    
     FIELD OF THE INVENTION 
     This disclosure relates to bipods for supporting projectile weapons such as firearms, rifles, airguns, crossbows or the like. 
     BACKGROUND 
     In order to achieve precision and accuracy in shooting activities such as hunting, shooting sports, military and law enforcement, etc. it is generally desirable to achieve and maintain stable alignment of a projectile weapon with a target and to minimize forces acting to disturb the alignment. Examples of disturbing forces that may disrupt alignment of a projectile weapon with an intended target include, but are not limited to, gravitational forces, shocks and/or vibrations, recoil, and forces applied by the operator, support structures and/or devices attached to the weapon. 
     Shocks and/or vibrations can be generated externally as well as inside the weapon during the shot. For weapons like rifles, causes of internally-generated shocks and/or vibrations include, but are not limited to, the movement of the rifle&#39;s mechanism, the explosive initiation of the propellant charge by the primer, the pressure waves created by the burning propellant inside the bore, and the friction between the accelerating projectile and the bore. Internally-generated shocks and/or vibrations may disturb alignment directly. Internally-generated shocks and/or vibrations may also disturb alignment by being reflected back to the weapon from a weapon support system attached to the weapon, such as a bipod, or from a support surface in direct or indirect contact with the weapon. Weapons may be affected by externally-generated shocks and/or vibrations for example, when shooting from a vehicle or aircraft. Alignment-disturbing forces may, in some circumstances, be mitigated by a skilled operator, but acquiring such skills requires time and money and even the best operators are susceptible to stress and fatigue. 
     Bipods are two-legged stands useful for stabilizing projectile weapons by mechanically supporting a portion of the weapon against a support surface. Bipods are typically designed to support part of the weight of a weapon at the weapon&#39;s front end, thereby allowing an operator to align the weapon with a target by supporting and moving the weapon from the rear end. Before the execution of a shot, it is generally desirable for the mounted weapon to have some degree of mobility to help an operator to align the weapon with a target, follow the target if it is moving, move from one target to another, and/or regain alignment for subsequent shots if alignment was lost, all in the shortest time possible and with minimal operator intervention. However, this mobility should be temporarily restricted during the execution of a shot to ensure that the weapon is stable and in proper alignment until the projectile leaves the weapon. After the projectile leaves the weapon, it is generally desirable for the weapon to immediately revert back to a state of high mobility relative to the bipod to, for example, allow the weapon to move rearwards under the recoil force (i.e. allowing for “follow through” of the weapon), allow any generated recoil energy to dissipate with minimal alignment disturbance enabling the operator to maintain uninterrupted visual contact with the target during and after the shot, and facilitate rapid re-alignment for a subsequent shot. 
     Prior art bipods that have a rigid connection between the weapon and the legs of the bipod are stable during the execution of the shot, but offer limited mobility of the weapon relative to the bipod. These bipods may also have a tendency to “jump” under recoil. Hence, an operator may need to reposition the bipod by lifting the bipod or dragging the feet of the bipod across the ground in order to align or realign the weapon. 
     Prior art bipods that allow relative movement between the weapon and the legs of the bipod provide easy target acquisition/alignment, but may be unstable during the execution of the shot. To improve stability, these types of bipods may employ a manually-operated mechanical lock (e.g. levers, threaded knobs, etc.) to secure the moving parts of the weapon-bipod system together after the weapon is aligned with the target. Such mechanical locks typically cannot be operated using only gross motor skills. To operate the lock, an operator may have to remove either his/her trigger hand or his/her support hand from the weapon, which may, for example, take time, create visible movement, break shooting stance, and lead to loss of precision and/or accuracy. In addition, the weapon becomes rigidly connected to the legs of the bipod after locking the moving parts of the weapon-bipod system together, thereby suffering from similar disadvantages as bipods that have a rigid connection as described above. 
     Prior art bipods that are built so that a force required to move the weapon relative to the legs of the bipod is adjustably pre-set with a tensioning knob, are essentially a compromise between the two types described above, with the disadvantage that the weapon and the legs are in the same state of relative mobility throughout the operation cycle and cannot transition quickly from a state of high mobility before or after the shot to a state of strong cohesion/rigidity during the shot. 
     Alignment of the weapon with an intended target is often achieved by aiming through an optical device (e.g. a telescopic sight), whose optical axis is placed above the bore (barrel) axis of the weapon. Accurate alignment (especially important for shots at longer distance) requires that the optical axis of the aiming device and the bore axis of the weapon are both kept in the same vertical plane. Vertical misalignment can be caused, for example, by operator error, uneven terrain, gravitational induced tilting of the weapon, etc. and may cause a discharged projectile to miss its intended target left or right of the aiming point. 
     Prior art bipods that are attached to the weapon at a point below the weapon&#39;s centre of gravity, and which allow relative movement between the legs of the bipod and the weapon, produce a tendency for the weapon to tilt over around the attachment point under the effect of gravity, which may result in vertical misalignment of the optical axis of the aiming device and the axis of the barrel. To achieve stable vertical alignment for a shot, the operator may observe a levelling device installed on the weapon such as a bubble level or similar device, and may adjust the vertical alignment manually by, for example, rotating the weapon relative to the support, adjusting the length of the legs and/or manually locking the bipod in alignment by operating a locking lever, using a pre-tensioning device, etc. This may add time and movement to the process of aligning a weapon with an intended target. 
     Prior art bipods where the bipod attaches to the weapon at a point above its centre of gravity may be inherently stable and help the weapon to level itself, similar to a pendulum. These designs may provide varying degrees of relative mobility between the legs of the bipod and the weapon. Some of these designs may be heavy and complex, some may have limited degrees of freedom along only one or two axes, and others may feel loose and may lack the possibility of transitioning from a state of high mobility before the execution of a shot to a state of high stability/rigidity (i.e. limited mobility) during the execution of the shot, and back to a state of high mobility after the execution of the shot. 
     Prior art portable bipods are generally not designed deliberately and systematically with shock and/or vibration isolating and/or damping features. Shot precision and accuracy may be increased when shock and/or vibration-damping supports, such as sand-bags, are used as compared to when shock and/or vibration-damping supports are not used. 
     Different shooting situations and positions require different bipod leg lengths and configurations. Prior art bipods may address this by having legs with lengths adjustable within a limited range. Such bipods typically cannot be adjusted over the entire range of lengths necessary for the bipod to be universally useable for any shooting position. For example, the legs of such bipods typically cannot be adjusted for an operator to transition from shooting the weapon in a prone position to a sitting and/or a standing position. Changing a shooting position with such bipods may require replacing the entire bipod, or may require using a different support device, such as a shooting stick or tripod, etc., when changing from one shooting position to another. 
     When a prior art bipod is not in use, the legs of the prior-art bipod may be folded and stored in a position parallel to the bore axis of the weapon, and underneath the fore-end of the weapon. This may interfere with shooting off-hand, shooting from a resting surface (commonly referred to as a “rest”) not attached to the weapon (e.g. a sandbag) and may prevent other accessories (e.g. fore grips, flashlights, lasers, slings, etc.) from being attached to the underside of the weapon. 
     There is a need for bipods that allow an attached weapon to transition quickly from a mobile state before the execution of a shot to a rigid state during the execution of the shot, and back to a mobile state after the execution of the shot. There is also a need for self-levelling bipods that minimize vertical misalignment between the optical axis of an aiming device (e.g. telescopic sight) and the bore axis of an attached weapon; reduction of direct and reflected shocks and/or vibrations between the weapon, the bipod and a support surface; modular attachment devices which allow a bipod to be removably attached to a multitude of weapon accessory interfaces; quick-detach, interchangeable legs of various lengths and configurations; and bipods with legs that store unobtrusively when not in use but are deployable by an operator quickly with only gross motor skills being required. There is also a need for bipods which achieve the foregoing while minimizing required operator movement and/or intervention (i.e. bipods which minimize introduction of disturbances which may misalign a weapon and/or increase a time required to align a weapon). 
     SUMMARY 
     This invention has a number of aspects. These aspects may be combined but may also be applied individually or in sub-combinations. These aspects include, without limitation:
         Bipods for supporting projectile weapons.   Bipods attachable above the center of gravity of projectile weapons in a self-levelling configuration.   Bipods configured to permit an attached weapon to rapidly transition between a mobile state and a rigid state.   Bipods which can be locked in a stable shooting position without the operator breaking shooting stance and without the need to operate external levers or similar devices.   Bipods which feature a friction lock between the bipod legs and the weapon.   Bipods configured to permit an attached weapon to move in 3 dimensions.   Bipods configured to permit continuous adjustment of the force required to move the weapon relative to the bipod.   Bipods configured to allow ambidextrous adjustments.   Bipods with modular attachment devices allowing a bipod to be removably attached to a multitude of weapon accessory interfaces.   Bipods configured to permit an attached weapon to rotate around multiple axes.   Bipods comprising legs deployable at various angles.   Bipods comprising legs that are quickly detachable.   Bipods comprising interchangeable legs.   Bipods comprising legs that can provide support against horizontal support surfaces as well as against other types of support surfaces including but not limited to vertical and angled surfaces.   Bipods with legs that store unobtrusively when not in use.   Bipods that are deployable by an operator quickly with only gross motor skills being required.   Bipods comprising components and materials useful for shock and/or vibration isolation and/or damping which reduce the direct and reflected shock and/or vibration between the weapon, the bipod and the support surface.   Bipods comprising feet that provide consistent contact and/or grip on varied surfaces and at various angles of leg deployment.       

     For the purpose of this application, a rigid state for a weapon may refer to, without limitation, a state where the weapon is attached to a bipod and the weapon is not free to move in relation to the bipod. For the purpose of this application, a mobile state for a weapon may refer to, without limitation, a state where the weapon is attached to a bipod but movable in relation to the bipod. 
     One example aspect of the invention provides bipods that permit an attached weapon to rapidly transition between a mobile state and a rigid state. Such bipods may comprise locking mechanisms that allow an operator to achieve a rigid state by applying, for example, forward pressure on the weapon against the bipod, also known by a person skilled in the art as “loading” the bipod. In some embodiments, the locking mechanism may be implemented through friction elements such as rubber bumpers that allow two parts of the bipod (e.g., a first component rigidly attached to the weapon, and a second component rigidly attached to the bipod) to frictionally engage each other in any relative position chosen by the operator. In these implementations, the weapon is locked relative to the bipod when the two parts of the bipod are frictionally engaged, but can move freely relative to the bipod when forward pressure is released and the two parts of the bipod are frictionally disengaged. 
     Another example aspect provides bipods attachable to a projectile weapon at a point above the projectile weapon&#39;s center of gravity. Advantageously, this can allow the weapon to level itself by hanging below the attachment point and reduces the likelihood of the weapon being in vertical misalignment due to gravity, uneven terrain, operator error, etc. 
     Another example aspect provides a bipod comprising a joint that allows an attached weapon to hang freely and pivot around the joint in multiple degrees of freedom. Depending on its design, the joint may provide various degrees of pan, roll and tilt. In some embodiments the joint comprises a tightening mechanism. In such embodiments, an operator can adjust the tightness of the tightening mechanism to control the mobility of an attached weapon along a spectrum ranging from a completely mobile state to a completely rigid state according to, for example, the operator&#39;s preference(s) or for storage purposes when the bipod is not in use. The bipod may further comprise ambidextrous controls for adjusting the tightness of the tightening mechanism. In some embodiments, the joint comprises a spherical joint. 
     A further example aspect provides bipods comprising legs that are rapidly deployable from a rest position to one or more positions suitable for firing an attached weapon (e.g. each position may, for example, be referred to as a “firing position”). In some embodiments, a firing position refers to an upright position where the legs of the bipod are oriented in a direction generally perpendicular to an attached weapon&#39;s bore axis, while a rest position refers to a position where the legs of the bipod are folded and secured in a direction generally parallel to an attached weapon&#39;s bore axis. Some embodiments provide bipods comprising legs that can be deployed and locked in position at various angles. The angle between the legs of the bipod and an attached weapon&#39;s bore axis may be indexed in several positions depending on shooting conditions and/or the operator&#39;s preference. 
     Some embodiments provide bipods comprising detachable legs thereby allowing an operator to switch between legs of various lengths to match a distance between the weapon and a support surface. Such distance may depend on terrain and/or factors, such as, an operator&#39;s height, shooting stance and/or shooting position. Some embodiments provide detachable legs that can be quickly removed and/or replaced without tools. 
     Some embodiments provide bipods comprising legs that fold along the sides of the fore-end of a weapon when not in use. In some embodiments, folding the legs along the sides of the fore-end of the weapon leaves the underside of the fore-end unobstructed. 
     Some embodiments provide bipods comprising legs that are partially or fully enclosed by elastomeric outer sleeves. The sleeves may advantageously provide improved shock and/or vibration damping, increased operator comfort in adverse environmental conditions (e.g. wet conditions, cold, heat, etc.), and/or better grip when shooting from unusual positions (e.g. with the legs or feet pressed against a vertical or angled support, when shooting downwards with the legs resting on a horizontal rope, shooting downwards from an aircraft, etc.). 
     Some embodiments provide bipods comprising feet that provide consistent grip on varied surfaces and at various angles of leg deployment. The feet may be made from rubber, polyurethane or other elastomeric materials useful for stabilizing the bipod against different types of support surfaces at various angles and also provide shock and/or vibration isolation and damping between the weapon, bipod, and support surface. 
     Some embodiments provide bipods comprising shock and/or vibration isolation and/or damping design elements and materials, which reduce alignment disturbances induced by shocks and/or vibrations. 
     Some embodiments provide bipods comprising modular attachment methods that allow quick attachment and detachment of the bipod to the weapon without tools and/or multiple standardized weapon accessory interfaces. 
     Further non-limiting exemplary aspects of the invention include:
     1. A bipod for supporting an attached projectile weapon, the bipod comprising:
       a base attachable to the projectile weapon;   a bracket shaped to receive the projectile weapon, the bracket comprising first and second opposing ends;   the base and bracket coupled at a kinematic joint to form a kinematic pair;   a first leg coupled to the first opposing end of the bracket;   a second leg coupled to the second opposing end of the bracket; and   the bracket frictionally engageable with the base to lock their relative movement as a means to stabilize the orientation of the projectile weapon relative to a target;   wherein the frictional engagement between the bracket and the base is disengageable by the weapon&#39;s operator or by the weapon&#39;s recoil force separating them apart; and   wherein the bipod provides a means for the supported projectile weapon to rapidly transition from a state of mobility relative to a target before the execution of a shot, to a state of stability relative to the target during the execution of the shot, and back to a state of mobility after the execution of the shot.   
       2. A bipod according to aspect 1 wherein one or both of the base and the bracket comprise at least one friction surface, allowing the base and the bracket to frictionally engage each other.   3. A bipod according to aspect 1 wherein the base and the bracket comprise:
       a first friction surface on the base, the first friction surface frictionally engageable with an opposing friction surface on the bracket by urging them together to provide a first friction lock, the first friction lock retaining the projectile weapon in a first plurality of predetermined orientations relative to the bracket; and   a second friction surface on the base, the second friction surface distal from the first friction surface on the base, the second friction element frictionally engageable with a second opposite friction surface on the bracket by urging them together to provide a second friction lock, the second friction lock retaining the projectile weapon in a second plurality of predetermined orientations relative to the bracket, the second plurality of orientations different from the first plurality of orientations;   wherein the first and second friction surfaces on the base and on the bracket are located on opposing sides of the joint.   
       4. A bipod according to aspect 1 wherein the joint between the base and the bracket comprises a spherical joint, and wherein the base and the attached projectile weapon can yaw, pitch and roll around three mutually orthogonal axes passing through the centre of the spherical joint.   5. A bipod according to aspect 4 wherein the spherical joint comprises a means for increasing and decreasing the force required to move the base relative to the bracket.   6. A bipod according to aspect 1 wherein the first and second legs are each pivotally coupled to the first and second opposing ends of the bracket respectively using a coupling mechanism, the coupling mechanism comprising a bracket pin engageable with a leg notch to lock the first and second legs in a leg deployment position relative to the bracket.   7. A bipod according to aspect 6 wherein the coupling mechanism further comprises a plurality of additional bracket pins engageable with the leg notch to lock the first and second legs in a plurality of additional leg deployment positions.   8. A bipod according to aspect 7 wherein the coupling mechanism further comprises a lever biased by a spring, the lever comprising a flared notch for receiving the bracket pin or one of the plurality of additional bracket pins whereby providing a means for the leg to be pivoted and locked in a plurality of leg deployment positions.   9. A bipod according to aspect 8 wherein the coupling mechanism further comprises:
       a concave shaped indentation on the bracket, the indentation shaped to receive a convex portion of the lever when one or both of the first and second legs are folded into a rest position generally parallel to the bore axis of the projectile weapon; and   a means of pivoting the leg without urging the lever from the said rest position to a first leg deployment position approximately downwards from and perpendicular to the bore axis of the projectile weapon, whereby allowing the projectile weapon operator to deploy the bipod legs using substantially only gross motor skills.   
       10. A bipod according to aspect 6 wherein each of the first and second legs comprise a leg member removably coupled to a leg cylinder, the leg cylinder pivotally coupled to the bracket.   11. A bipod according to aspect 10 wherein the leg member is removably coupled to the leg cylinder using a bayonet mechanism.   12. A bipod according to aspect 10 wherein the first and second legs are interchangeable with legs different in length from a first length to a second length different from the first length.   13. A bipod according to aspect 1 wherein at least one of the first and second legs comprises a toroidal shaped foot attached to the at least one of the first and second legs with the toroid axis of revolution perpendicular to the axis of the leg, thereby presenting substantially uniform contact surface around the foot&#39;s circumference, whereby providing substantially consistent contact between the feet and a support surface in a plurality of leg deployment positions.   14. A bipod according to aspect 13 wherein at least one of the toroidal shaped feet attached to at least one of the first and second legs is constructed similar to a vehicle tire from materials such as rubber, elastomer, or other suitable materials, and the outside surface of the toroidal shaped feet has treads, whereby providing a means for substantially increasing said foot&#39;s grip on the support surface.   15. A bipod according to aspect 13 wherein, when the legs are deployed in a position approximately downwards from and perpendicular to the bore axis of the projectile weapon, each of the feet attached to the first and second legs are oriented inwards towards the bore axis of the projectile weapon in a wedge shape, whereby providing a means for substantially increasing the grip of the feet against the support surface.   16. A device for supporting an attached projectile weapon, comprising:
       one or more legs that support all or part of the weight of the attached projectile weapon by transferring said weight to a support surface;   a means of attaching the legs to the projectile weapon; and   buffering members sandwiched between at least two contiguous elements of the device, constructed in shapes and from materials suitable to dampen and isolate vibrations, such as polymers, elastomers, foam, etc.;   whereby providing a means for substantially reducing the effect of direct and reflected vibrations to disturb a predetermined alignment with a target of an attached projectile weapon.   
       17. A bipod according to aspect 16 wherein at least one of the legs comprises an outer sleeve surrounding at least part of the leg, the outer sleeve made of a material, shape and size suitable for damping vibrations, such as rubber, elastomer, polymer, foam, etc.   18. A method for stabilizing a projectile weapon, the method comprising:
       attaching the projectile weapon to a bipod, the bipod comprising:
           a base attachable to the projectile weapon;   a bracket shaped to receive the projectile weapon, the bracket comprising first and second opposing ends;   the base and bracket coupled at a kinematic joint to form a kinematic pair;   a first leg coupled to the first opposing end of the bracket;   a second leg coupled to the second opposing end of the bracket; and   the bracket frictionally engageable with the base to lock their relative movement;   
           resting the bipod legs on a support surface;   frictionally disengaging the base from the bracket by moving the projectile weapon in a predetermined direction, thereby allowing the weapon to yaw, pitch and roll relative to the support surface;   aligning the projectile weapon with a target; and   when a predetermined alignment of the projectile weapon with the target has been achieved, frictionally engaging the base with the bracket by moving the projectile weapon in a predetermined direction and thereby locking the relative position between the weapon and the support surface, whereby stabilizing the alignment of the projectile weapon with the target for the execution of the shot.   
       19. A method according to aspect 18 wherein frictionally disengaging the base from the bracket is achieved by the projectile weapon&#39;s recoil force separating them apart, whereby allowing the projectile weapon to move rearwards under the recoil force while reducing the movement of the legs relative to the support surface.   20. A bipod for supporting an attached projectile weapon, the bipod comprising:
       a bracket shaped to receive the projectile weapon, the bracket comprising first and second opposing ends;
           a first leg coupled to the first opposing end of the bracket;   a second leg coupled to the second opposing end of the bracket; and   a base attachable to the projectile weapon, the base pivotally coupled to the bracket at a joint located between the first and second opposing ends of the bracket, the base frictionally engageable with the bracket to retain the projectile weapon in a desired orientation relative to the bipod.   
           
       21. A bipod according to aspect 20 wherein one or both of the base and the bracket comprise at least one friction element, the friction element increasing a coefficient of friction between the base and the bracket when the base frictionally engages the bracket.   22. A bipod according to aspect 21 wherein the at least one friction element is made of a material for damping one or both of shock and vibration of the bipod.   23. A bipod according to aspect 20 wherein the base comprises:
       a first friction element coupled to a first end of a top surface of the base, the first friction element frictionally engageable with a bottom surface of the bracket to provide a first friction lock, the first friction lock retaining the projectile weapon in a first plurality of orientations relative to the bipod; and   a second friction element coupled to a second end of the top surface of the base, the second end distal from the first end, the second friction element frictionally engageable with the bottom surface of the bracket to provide a second friction lock, the second friction lock retaining the projectile weapon in a second plurality of orientations relative to the bipod, the second plurality of orientations different from the first plurality of orientations;   wherein the first and second friction elements are coupled to the top surface of the base on opposing sides of the joint.   
       24. A bipod according to aspect 20 wherein the joint comprises an adjustable tightening mechanism, wherein adjusting the adjustable tightening mechanism adjusts a range of pivotal movement of the joint relative to the bracket.   25. A bipod according to aspect 24 wherein the joint comprises a spherical joint, and wherein the base is pivotally movable around three mutually orthogonal axes passing through the spherical joint.   26. A bipod according to aspect 20 wherein the first and second legs are each pivotally coupled to the first and second opposing ends of the bracket respectively using a coupling mechanism, the coupling mechanism comprising a bracket pin engageable with a leg notch to lock the first and second legs in a first position relative to the bracket.   27. A bipod according to aspect 26 wherein the firing position comprises a position where an angle between a central axis of each of the first and second legs and the projectile weapon&#39;s bore axis is 90°.   28. A bipod according to aspect 26 wherein the coupling mechanism further comprises a plurality of additional bracket pins engageable with the leg notch to lock the first and second legs in a plurality of positions different from the first position.   29. A bipod according to aspect 28 wherein the plurality of firing positions comprises positions where an angle between a central axis of each of the first and second legs and the projectile weapon&#39;s bore axis is 0°, 30° and 60°.   30. A bipod according to aspect 26 wherein the coupling mechanism further comprises a bushing made of a material for damping one or both of shock and vibration of the bipod.   31. A bipod according to aspect 26 wherein the coupling mechanism further comprises a lever biased by a spring, the lever comprising a flared notch for receiving the pin.   32. A bipod according to aspect 31 wherein the coupling mechanism further comprises an indentation, the indentation shaped to receive the lever when folding one or both of the first and second legs into a rest position.   33. A bipod according to aspect 32 wherein the indentation comprises a concave-shape and the lever comprises a convex portion, the convex portion of the lever receivable by the concave indentation.   34. A bipod according to aspect 33 wherein the flared notch is releasable from the indentation when mechanical force is exerted to rotate one or both of the first and second legs from the rest position to the first position, wherein releasing the flared notch from the indentation requires only gross motor skills of an operator of the projectile weapon.   35. A bipod according to aspect 20 wherein each of the first and second legs comprise a leg member removably coupled to a leg cylinder, the leg cylinder pivotally coupled to the bracket.   36. A bipod according to aspect 35 wherein the leg member is removably coupled to the leg cylinder using a bayonet mechanism.   37. A bipod according to aspect 20 wherein at least one of the first and second legs comprises an outer sleeve, the outer sleeve made of a material for damping one or both of shock and vibration of the bipod.   38. A bipod according to aspect 20 wherein at least one of the first and second legs comprises a foot attached to the at least one of the first and second legs, the foot made of a material for damping one or both of shock and vibration of the bipod and the foot comprising a surface engageable with a supporting surface wherein engagement of the surface with the supporting surface increases a coefficient of friction between the bipod and the supporting surface when the bipod is rested on the supporting surface.   39. A bipod according to aspect 20 wherein each of the first and second legs are pivotally movable inwards towards a bore axis of the projectile weapon.   40. A bipod according to aspect 20 wherein the first and second legs are extendible in length from a first length to a second length different from the first length.   41. A method for stabilizing an attached projectile weapon, the method comprising:
       removably attaching the projectile weapon to a bipod, the bipod comprising:
           a bracket shaped to receive the projectile weapon, the bracket comprising first and second opposing ends;   a first leg coupled to the first opposing end of the bracket;   a second leg coupled to the second opposing end of the bracket; and   a base attachable to the projectile weapon, the base pivotally coupled to the bracket using a joint located between the first and second opposing ends of the bracket, the base frictionally engageable with the bracket to retain the projectile weapon in a desired orientation relative to the bipod;   
           resting the bipod on a surface; and   frictionally engaging the base with the bracket using the weight of the projectile weapon, a force applied to the projectile weapon by an operator of the projectile weapon, or both.   
       42. A bipod for supporting a projectile weapon, the bipod comprising:
       a bracket attachable to the projectile weapon above the projectile weapon&#39;s center of gravity;   a first leg cylinder and a second leg cylinder pivotally attached to opposing ends of the bracket respectively;   a first leg member attachable to the first leg cylinder;   a second leg member attachable to the second leg cylinder; and   a base to which the projectile weapon may be affixed, the base attachable to the bracket at a joint located between the opposing ends of the bracket, the base having a first friction element at a top surface of the base, the first friction element frictionally engageable with the bracket so as to provide a first friction lock between the affixed projectile weapon and the bipod.   
       43. A bipod according to aspect 42 wherein the joint comprises a spherical joint and wherein, the base is rotatable around three mutually orthogonal axes passing through the spherical joint.   44. A bipod according to aspect 43 wherein the spherical joint comprises a radial gap on an outer race of the joint, the radial gap having an adjustable width to tighten or loosen the spherical joint relative to the outer race.   45. A bipod according to aspect 42 wherein the first friction element is made of rubber, polyurethane or other elastomeric materials.   46. A bipod according to aspect 42 wherein the first leg cylinder and the bracket are secured to each other by a pin positioned on the bracket and engageable with a notch located on the first leg cylinder so as to lock the first leg cylinder in a firing position.   47. A bipod according to aspect 46 wherein the firing position comprises a position where the angle between the central axis of the first leg member and the attached projectile weapon&#39;s bore axis is 90°.   48. A bipod according to aspect 46 wherein the first leg cylinder and the bracket are further secured with one another by a plurality of additional pins so as to lock the first leg cylinder in a plurality of firing positions.   49. A bipod according to aspect 48 wherein the plurality of firing positions comprise positions where the angle between the central axis of the first leg member and the attached projectile weapon&#39;s bore axis is 0°, 30° and 60°.   50. A bipod according to aspect 46 wherein the first leg cylinder comprises a lever biased by a spring, the first leg cylinder engages a flared notch of the lever when the flared notch receives the pin.   51. A bipod according to aspect 50 wherein the bracket comprises an indentation, the lever receivable by the indentation to fold the first leg cylinder into a rest position.   52. A bipod according to aspect 51 wherein indentation comprises a concave-shape and the lever comprises a convex portion, the convex portion of the lever is receivable by the concave indentation to fold the first leg cylinder into the rest position.   53. A bipod according to aspect 52 wherein the flared notch is releasable from the indentation when mechanical force is exerted to rotate the first leg cylinder from the rest position to the firing position.   54. A bipod according to aspect 46 wherein the bracket comprises a second pin located at a second end of the bracket, the second leg cylinder engageable with the second pin to lock the second leg cylinder in a firing position.   55. A bipod according to aspect 42 wherein the first leg member is attachable to the first leg cylinder and the second leg member is attachable to the second leg cylinder, the first and second leg members are respectively removably attached to the first and second leg cylinders through a bayonet mechanism.   56. A bipod according to aspect 42 wherein at least one of the first leg member and second leg member comprises an outer sleeve, and wherein the outer sleeve is made of one or more of rubber, polyurethane, and other elastomeric materials.   57. A bipod according to aspect 42 wherein at least one of the first and second leg members comprises a foot attachable to the at least one of the first and second leg members.   58. A bipod according to aspect 57 wherein the foot is made of rubber, polyurethane, or other elastomeric materials.   59. A bipod according to aspect 57 wherein the foot is toroidal-shaped.   60. A bipod according to aspect 57 wherein the foot comprises a plurality of treads around the outer circumference of the foot.   61. A bipod according to aspect 42 wherein the bracket further comprises a shaft protruding outwardly from an end surface of the bracket, and wherein a bushing is engageable with the shaft and a bore within the leg cylinder.   62. A bipod according to aspect 61, wherein the bushing is made of any one or more of a shocks and/or vibrations damping material, shocks and/or vibrations isolating material and self-lubricating material.   63. A bipod according to aspect 42 wherein the bracket comprises a pair of downwardly extending arms positioned at opposing ends of the bracket, each of the arms respectively pivotably engageable with the first and second leg cylinder for allowing the positioning of the first and/or second leg members.   

     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
         FIG. 1  is a perspective view of an example embodiment of a bipod with its legs deployed in an example firing position. 
         FIG. 1A  is an expanded perspective view of an example embodiment of a leg. 
         FIG. 2  is a rear view of the bipod according to the  FIG. 1  embodiment. 
         FIG. 2A  is an expanded perspective view of an example bipod. 
         FIG. 2B  is an expanded perspective view of an example bipod. 
         FIG. 3A  is a perspective view of the bipod base and bearing assembly attached to the bipod shown in  FIG. 1 . 
         FIG. 3B  is a perspective view of another example embodiment of a bipod base and bearing assembly. 
         FIG. 3C  is a perspective view of an example embodiment of a spherical joint attachable to the bipod bases shown in  FIGS. 3A and 3B . 
         FIG. 3D  is a perspective view of a bipod bracket designed to receive a bipod base like those shown in  FIGS. 3A and 3B . 
         FIGS. 4A to 4C  are schematic views of example friction locks between a base and a bracket of a bipod. 
         FIG. 5  is a side view of an example bipod in an alternate position with its legs folded in an example rest position. 
         FIG. 6  is an expanded schematic view illustrating a mechanism for deploying and locking the legs of a bipod in various positions according to an example embodiment. 
         FIGS. 7 to 9  are perspective views of another example embodiment of a bipod. 
         FIG. 10  is a cross-sectional view of a base, joint and bracket of the bipod shown in  FIGS. 7 to 9 . 
         FIG. 11  is a perspective view of an example embodiment of a bipod with its legs deployed in an example forward firing position. 
         FIG. 12  is a top view illustrating the feet of the bipod angled inwards to improve stability according to an example embodiment. 
         FIG. 13  is a perspective view of an example foot. 
     
    
    
     DETAILED DESCRIPTION 
     Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
       FIG. 1  is a perspective view of bipod  100  according to an example embodiment. Bipod  100  comprises bracket  20 , base  40 A and legs  70 A,  70 B (collectively legs  70 ). Bracket  20  may be generally reverse U-shaped to provide a generally flat platform  21  sandwiched between two arms  22 A,  22 B (collectively arms  22 ) that extend in generally downward directions and are angled away from platform  21  (as shown in  FIGS. 1 and 2 ). In some embodiments, platform  21  forms a base of a trapezoid and arms  22  form the sides of the trapezoid. In some embodiments, arms  22  are not angled away from platform  21  (i.e. arms  22  are perpendicular to platform  21 ). Platform  21  provides a solid surface for mechanically coupling base  40 A to bipod  100 . Legs  70  may, for example, be pivotally coupled to arms  22  of bracket  20 . In some embodiments, legs  70  are rigidly coupled to arms  22 . Bracket  20  may, for example, be made from any suitable material including but not limited to various metals, reinforced polymers or the like. In some embodiments, bracket  20  and/or legs  70  are made of one or more composite materials. 
     In some embodiments, see e.g.  FIGS. 1 and 1A , one or both of legs  70  each comprises a leg cylinder  60  (i.e. leg cylinder  60 A or  60 B), a leg member  80  (i.e. leg member  80 A or  80 B) and a foot  90  (i.e. foot  90 A or  90 B). In such embodiments, a leg cylinder  60  pivotally couples a leg member  80  to an arm  22 . Leg members  80  may, for example, be made from tubes of metal, reinforced polymer or other suitable material to provide structural rigidity. 
     Optionally, a leg  70  may comprise an outer sleeve  82  (i.e. outer sleeve  82 A or  82 B). Outer sleeve  82  dampens shock and/or vibration experienced by bipod  100  and may be equivalent to the elastomeric outer sleeves described elsewhere herein. Outer sleeves  82  (i.e. outer sleeves  82 A and/or  82 B) may, for example, be made of rubber, polyurethane or other materials suitable for damping of shocks and/or vibrations travelling along legs  70 . 
     Feet  90  may, for example, be made from materials including, but not limited to, rubber, polyurethane, other suitable elastomeric material, etc. Feet  90  may be made from material with good abrasion and/or UV resistance. In some embodiments, feet  90  may have an approximately toroidal shape similar to the shape of vehicle tires (as shown in  FIG. 13 , for example). The toroidal shape may help feet  90  maintain consistent contact with a support surface, regardless of the position and/or angle of legs  70  relative to a mounted weapon&#39;s bore axis. A generally round profile may also allow feet  90  to rotate on a support surface instead of jumping under recoil. In some embodiments, feet  90  may comprise treads  91  (see  FIG. 13 , for example) around their circumference to improve grip on different surfaces. The construction and materials of feet  90  may also provide damping and isolation of direct and reflected shocks and/or vibrations traveling between the weapon through the bipod to and from a support surface. Foot  90 A and foot  90 B may be identical, similar or different from each other. 
     Feet  90 A,  90 B may, for example, be connected to leg members  80 A,  80 B with pinned connections where leg members  80  pass through a socket in feet  90  and are attached to feet  90  by inserting pins (not shown) through the centre of feet  90  and holes  92  in leg members  80 . In some embodiments, feet  90  are permanently attached to leg members  80 . In other embodiments, feet  90  are detachable from leg members  80 . Feet  90 A,  90 B may, for example, comprise treads  91 A,  91 B respectively (collectively tread  91 ). 
     As illustrated in  FIG. 1A , a leg  70  may comprise a pin  81  engageable with a leg cylinder  60  through, for example, a bayonet mechanism. Such mechanism allows for a leg member  80  to be easily and quickly detached and/or reattached to a leg cylinder  60 . This mechanism also allows for a leg  80  to be easily and quickly exchanged for a leg  80  having a different length and/or configuration. In some embodiments, the bayonet mechanism described herein may comprise a spring  65  (see  FIG. 6 ) within leg cylinder  60 . Compression of spring  65  by a coupled leg member  80 , for example, exerts a spring force against leg member  80  engaging pin  81  with guide channel  62  of leg cylinder  60 . Engagement of pin  81  with guide channel  62  may, for example, prevent inadvertent uncoupling of a leg member  80  from its corresponding leg cylinder  60 . 
       FIG. 2  is a rear view of bipod  100 . Leg  70 A may be identical to, or different from, leg  70 B. In some embodiments, arm  22 A, leg cylinder  60 A, leg member  80 A and foot  90 A are identical counterparts of arm  22 B, leg cylinder  60 B, leg member  80 B and foot  90 B respectively. In some embodiments, at least one of arm  22 A and arm  22 B, leg cylinder  60 A and leg cylinder  60 B, leg member  80 A and leg member  80 B, or foot  90 A and foot  90 B is different from its corresponding part forming the collective. For example, leg cylinder  60 A and leg cylinder  60 B may be mirror counterparts of each other while leg member  80 A and foot  90 A may be identical to leg member  80 B and foot  90 B. 
     In some embodiments, one or more parts corresponding to legs  70 A and  70 B are interchangeable. For example, leg cylinders  60 A and  60 B may be interchangeable (e.g. leg cylinder  60 B may be coupled to arm  22 A and leg cylinder  60 A may be coupled to arm  22 B). Alternatively, or in addition, leg members  80 A and  80 B may be interchangeable (e.g. leg member  80 B may be coupled to leg cylinder  60 A and leg member  80 A may be coupled to leg cylinder  60 B). As a further alternative, or further addition, feet  90 A and  90 B may be interchangeable (e.g. foot  90 B may be coupled to leg member  80 A and foot  90 A may be coupled to leg member  90 B). 
     Base  40 A is mechanically couplable to bracket  20  at platform  21  through mounting joint  50 . A projectile weapon (not shown) can be attached to base  40 A, thereby mounting the projectile weapon to bipod  100 . In some embodiments, the projectile weapon (e.g., a rifle) may comprise various types of proprietary modular mounting interface devices (e.g., Picatinny rails, M-LOK® rail, Keymod™ rail, etc.) and base  40 A may be removably attached to various clamping or other attachment devices (not shown) to allow base  40 A to attach to different types of mounting interfaces that may be present on a weapon. In some embodiments, base  40 A is rigidly attached to the projectile weapon. 
     In some embodiments, base  40 A may, for example, comprise rounded edges or ends as shown in  FIG. 2B . 
     In the embodiment shown in  FIGS. 1 and 2 , base  40 A attaches to bracket  20  below platform  21 . Hence, a projectile weapon will attach to base  40 A directly or through an adaptor at a point above the projectile weapon&#39;s center of gravity in, for example, a self-levelling configuration. In some embodiments, joint  50  may comprise bearings or the like that allow base  40 A (and a mounted weapon) to pan, tilt and roll relative to bracket  20  (i.e. joint  50  allows for three degrees of freedom in such embodiments). In some embodiments, the bearings may be spherical. 
       FIG. 3A  is a perspective view of an example embodiment of base  40 A, mounting joint  50 , tension screw  42  and handle  43  disengaged from bracket  20 . In some embodiments, mounting joint  50  comprises a tightening mechanism. Such tightening mechanism may, for example, be used to restrict movement of base  40 A relative to bracket  20  and may comprise means for varying an amount by which movement of base  40 A relative to bracket  20  is restricted. For example, the tightening mechanism may comprise race  51  described elsewhere herein in combination with tension screw  42  (i.e. the means for varying the amount by which movement of base  40 A relative to bracket  20  is restricted). 
       FIG. 3B  is a perspective view of an example embodiment of base  40 B, mounting joint  50 , tension screw  42  and handle  43  disengaged from bracket  20 . In some embodiments, base  40 A and base  40 B can be interchanged with each other. 
     In some embodiments, mounting joint  50  has three degrees of freedom (e.g. pan, tilt and roll relative to bracket  20 ) allowing base  40 A or  40 B to pivot relative to bracket  20  about three different axes of rotation passing through mounting joint  50 . In such embodiments, mounting joint  50  may comprise a spherical bearing. 
       FIG. 3C  is a perspective view of an example embodiment of mounting joint  50 , where mounting joint  50  comprises a race  51 , mounting screw  52  and ball  53 . In some embodiments, bracket  20  may comprise a hole  25  (as shown in  FIG. 3D ) passing through the center of platform  21  to receive mounting joint  50 . Hole  25  may comprise a shouldered layer  26  (as shown in  FIG. 3D ) at or near the bottom surface of platform  21  to support race  51  inside hole  25 . 
     Mounting joint  50  may engage bracket  20  by sitting on shouldered layer  26  as described above, or via other means. Ball  53  of mounting joint  50  may be attached to raised boss  45  at the top of base  40 A or  40 B with mounting screw  52  while leaving a gap between the bottom surface of platform  21  and top surface  41  of base  40 A or  40 B. This configuration allows base  40 A or  40 B to remain attached to bracket  20  (through mounting joint  50 ) while being able to move freely around the center of mounting joint  50  at the same time. 
     In some embodiments, race  51  may comprise radial gap  55  (as shown in  FIG. 3C ). Radial gap  55  may be tightened or loosened to adjust the tightness of race  51  around ball  53 . Increasing the tightness of race  51  increases the force required to move attached base  40 A or  40 B relative to bracket  20 , whereas decreasing the tightness of race  51  decreases this force. 
     In some embodiments, bracket  20  may comprise bore  27  for receiving a screw or the like to adjust the tightness of a tightening mechanism corresponding to a mounting joint  50 . The bore may extend in a direction generally perpendicular to both a bore axis (e.g. line  101  in  FIG. 5 ) of a mounted weapon and a central axis of hole  25  receiving mounting joint  50 . 
     In the example embodiment shown in  FIG. 3A , tension screw  42  with adjustable handle  43  can be threaded through bore  27  of bracket  20  to engage race  51  at about a right angle to radial gap  55  (in such embodiments, bore  27  comprises a thread pattern corresponding to the thread pattern of tension screw  42 ). By turning handle  43 , tension screw  42  presses radially towards or away from race  51  depending on the direction of rotation of handle  43 . Radial gap  55  allows race  51  to tighten or loosen around ball  53  to respectively increase or decrease friction between ball  53  and race  51 . Hence, pivotal movement of an attached base  40 A can be restricted or expanded relative to bracket  20  by turning handle  43 . In some embodiments, either end of bracket  20  may receive handle  43  and tension screw  42  thereby supporting ambidextrous adjustment of handle  43  (i.e. both sides of bracket  20  comprise a bore  27  as shown, for example, in  FIG. 3D ). 
     Coupling base  40 A to bracket  20  using mounting joint  50  results in a corresponding gap extending between a surface of base  40 A (e.g. top surface  41  (see  FIG. 3A )) and an opposing surface of bracket  20  (e.g. a bottom surface of platform  21 ). Such gap provides a “locking mechanism” allowing base  40 A to rapidly transition from a mobile state (where base  40 A may pivot freely (i.e. pan, tilt and/or roll) relative to bracket  20  as described elsewhere herein) and a rigid state (where base  40 A cannot pivot freely relative to bracket  20  as described elsewhere herein). In some embodiments, the locking mechanism comprises, for example, a surface of base  40 A frictionally engaging an opposing surface of bracket  20 . In such embodiments, friction between the surface of base  40 A and the opposing surface of bracket  20  precludes pivotal movement of base  40 A relative to bracket  20 . In some embodiments, base  40 A may comprise one or more frictional elements frictionally engageable with the opposing surface of bracket  20  for increasing a coefficient of friction between base  40 A and bracket  20 . Such frictional elements may be made from any suitable materials including, but not limited to, rubber, polyurethane or the like. 
     In some embodiments, as shown in  FIG. 3A  for example, base  40 A comprises friction elements  44 A,  44 B. Friction elements  44 A,  44 B may, for example, be attached to top surface  41  of base  40 A. In some embodiments, friction elements  44 A,  44 B form a part of top surface  41 . Friction elements  44 A,  44 B may or may not be identical to each other. Friction elements  44 A,  44 B may be made from different materials, shaped differently, designed with different thicknesses from each other, etc. In some embodiments, friction elements  44 A,  44 B may have cross-sections that are rectangular, circular, triangular, pentagonal, hexagonal, octagonal or the like. 
     The thickness of friction elements  44 A,  44 B and/or the height of boss  45  can be chosen so as to leave a small gap between the top of friction elements  44 A,  44 B and platform  21  when bipod  100  is in a “neutral” state (e.g. a state where an attached weapon has not been aligned with an intended target) (see  FIG. 4A ). When an operator frictionally engages top surface  41  with platform  21 , base  40 A and bracket  20  are “locked” together transitioning base  40 A from a mobile state to a rigid state. Due to, for example, the relatively small size of the gap between friction elements  44 A,  44 B and platform  21  and the fulcrum provided by the length of a mounted weapon, the weapon only needs to move a short distance to create contact friction strong enough to lock base  40 A against bracket  20 . Hence, an operator can align a weapon with a target by freely rotating base  40 A around mounting joint  50 , and once proper alignment has been achieved and the operator is ready to fire, s/he can stabilize the weapon quickly and with minimal movement in a multitude of positions during shot execution by frictionally engaging base  40 A with bracket  20 . Locking can be achieved in any relative position between base  40 A and bracket  20 , as chosen by the operator for proper alignment with the target. 
     Upon firing of a shot, recoil forces may automatically unlock base  40 A (e.g. transition base  40 A from a rigid state to a mobile state) allowing the weapon to move freely rearward and allowing for more of the recoil force to be directed and dissipated in a direction along the bore axis, which may improve precision and accuracy and may allow for better shot follow-through (e.g. by an operator&#39;s body absorbing a portion of the recoil forces, bipod  100  absorbing a portion of the recoil forces, etc.). It will be appreciated that in operation in certain leg deployment positions, such as that exemplified in  FIG. 1 ., base  40 A, joint  50 , legs  70  and the circular contact surface between feet  90  and the support surface form and act as a parallelogram mechanism which in use allows the bracket to translate backwards as the weapon recoils during a shot, allowing the coupled weapon to move relatively freely and quasi-linearly backwards under recoil. This may advantageously reduce disturbances to alignment, improve precision and accuracy, and prevent the bipod from “jumping” upon recoil which would require re-alignment of the bipod for a subsequent shot. 
     Friction elements  44 A,  44 B do not need to engage platform  21  at the same time to stabilize a mounted weapon. In some embodiments, only one of friction elements  44 A,  44 B engages platform  21  at any given time depending on factors including but not limited to the design of friction elements  44  (i.e. friction elements  44 A,  44 B), the position of legs  80 , the angle of shooting, etc. For example, friction element  44 A may act as a front bumper useful for locking a mounted weapon in position when legs  70  are deployed in a direction generally perpendicular to the bore axis of the mounted weapon (as shown in  FIG. 4B ), while friction element  44 B may act as a rear bumper (as shown in  FIG. 4C ) useful for locking a mounted weapon in position when legs  70  are deployed in alternative shooting positions (e.g. a forward position as seen in  FIG. 11 ). 
     In some embodiments, friction element  44 B may aid in arresting and/or dissipating rearward movement of a weapon under recoil. 
     As described elsewhere herein,  FIG. 4A  schematically illustrates bipod  100  in a neutral position. In such position, a surface of base  40 A is not frictionally engaged with an opposing surface of bracket  20  allowing for pivotal movement of base  40 A relative to bracket  20  (i.e. base  40 A is in its mobile state).  FIGS. 4B and 4C  schematically illustrate bipod  100  in example locked positions. In such positions, friction element  44 A ( FIG. 4B ) or friction element  44 B ( FIG. 4C ) frictionally engage the opposing surface of bracket  20  precluding pivotal movement of base  40 A relative to bracket  20  (i.e. base  40 A is in its rigid state). Base  40 A and/or frictional elements  44 A,  44 B may, for example, be frictionally engaged with an opposing surface of bracket  20  by one or both of a weight of the weapon and a force applied to the weapon by the operator (e.g. a force applied to a stock of the weapon in a direction towards bipod  100 , through a technique known to persons skilled in the art as “loading the bipod”). 
     Although the exemplary schematic illustrations of bipod  100  in  FIGS. 4A to 4C  illustrate a base  40 A comprising two friction elements  44 A,  44 B, a person skilled in the art will readily understand based on the disclosure of the invention herein that base  40 A may frictionally engage an opposing surface of bracket  20  in alternate embodiments where base  40 A comprises no friction elements (i.e. a surface of base  40 A directly frictionally engages an opposing surface of bracket  20 ), a single friction element or more than two friction elements. 
     In some embodiments, only base  40 A comprises one or more friction elements described herein. In some embodiments, one or more of the friction elements described herein may be attached to, or form a part of, a surface of bracket  20 . In such embodiments, both base  40 A and bracket  20  may comprise friction elements. In alternate embodiments, only bracket  20  comprises friction elements. 
       FIG. 5  is a side view of bipod  100  comprising legs  70  retracted into a rest position (alternatively may be referred to as a “storage” position). 
     In the example embodiment shown in  FIG. 5 , leg cylinder  60 B is pivotally connected to bracket  20  at arm  22 B. Leg cylinder  60 B may comprise lever  61 B biased by a spring (e.g. spring  65 B shown in  FIG. 6 ). In some embodiments, leg  70 B can be deployed from a rest position to a firing position (as shown in  FIG. 2 ) by actuating lever  61 B. In some embodiments, leg  70 B can be deployed from a rest position to a firing position by mechanically rotating leg  70 B around the pivoted connection without the need to actuate lever  61 B. This allows for quick deployment of leg  70 B from its rest position to its firing position. Leg  70 A may be coupled to bracket  20  at arm  22 A in an identical, similar, or different way. 
       FIG. 6  is an expanded schematic view illustrating an example mechanism for deploying and locking legs  70  of bipod  100  in various firing positions according to an example embodiment. To avoid obscuring the schematic illustration of  FIG. 6 , only a single leg  70  (i.e. leg  70 A) is illustrated. The mechanism described below may be equally applied to leg  70 B. 
     In the example embodiment shown in  FIG. 6 , arm  22 A comprises shaft  30 A (counterpart of shaft  30 B, see  FIG. 3D  for shaft  30 A). Shaft  30 A may mate with a bore in cylinder  60 A (not shown in  FIG. 6 ), whereby cylinder  60 A is pivotally attached to arm  22 A. Shaft  30 A may comprise an axial threaded hole, receiving side screw  31 A. Side screw  31 A and washer  32 A secure leg cylinder  60 A against arm  22 A while allowing leg cylinder  60 A to pivot about a central axis passing through shaft  30 A. 
     In some embodiments, bushing  35 A (see  FIG. 2B , for example) is mounted over shaft  30 A and is received within a bore of leg cylinder  60 A. Likewise, a bushing may be mounted over shaft  30 B. Such bushing and bushing  35 A may be collectively referred to as bushings  35 . In some embodiments, bushings  35  may be used to reduce rotational friction and/or to isolate the transmission of shocks and/or vibrations between bracket  20  and leg cylinders  60 A,  60 B respectively. One or both of bushings  35  may, for example, be a cylindrical bushing, a flange bushing or the like. 
     In some embodiments, arm  22 A may comprise indexing pins  23 A and an indentation  24 A. Pins  23 A and indentation  24 A may, for example, be distributed around an arcual groove extending circumferentially around the end of arm  22 A (as partially shown in  FIG. 3D ). Leg cylinder  60 A engaging bracket  20  through shaft  30 A may comprise lever  61 A pivotable around anchor pin  63 A and biased against spring  65 A (e.g. a spring identical to, or a counterpart of, spring  65 B). Lever  61 A may comprise a flared notch  64 A capable of engaging position pins  23 A or resting in indentation  24 A (e.g. a flared notch identical to, or a counterpart of, flared notch  64 B). 
     When leg member  80 A (or leg  70 A) is folded in its storage position, flared notch  64 A snuggly rests in indentation  24 A. In some embodiments, indentation  24 A comprises a pin similar to indexing pins  23 A such that an operator needs to press lever  61 A against spring  65 A to disengage flared notch  64 A from the pin to deploy leg member  80 A (or leg  70 A) from its storage position to a firing position. In some embodiments, indentation  24 A does not have any such pin. In such embodiments, indentation  26 A and flared notch  64 A are shaped to allow the side part of flared notch  64 A to slide up on a ramp and release from indentation  24 A and slide on a raised segment of the circumferential groove at the end of arm  22 A when an operator applies force to rotate leg member  80 A (or leg  70 A) around the axis of shaft  30 A to deploy in its firing position. The ramp profile in indentation  24 A and corresponding profile of the side of flared notch  64 A allows leg cylinder  60 A to pivot around shaft  30 A without the need for an operator to activate a release mechanism to rotate leg member  80 A into a firing position. 
     In the example embodiment shown in  FIG. 6 , arm  22 A comprises four position pins  23 A that correspond to different firing positions. When an operator applies force to pivot leg cylinder  60 A (and attached leg member  80 A) around shaft  30 A, flared notch  64 A slides along the circumferential groove at the end of arm  22 A until it engages the first pin of indexing pins  23 A (as seen in  FIG. 6 ). Flared notch  64 A may, for example, be designed to eliminate play and maintain a play-free engagement over a long period of time by compensating for wear. Spring  65 A applies pressure on lever  61 A to ensure that flared notch  64 A firmly engages an indexing pin  23 A. 
     In the example embodiment shown in  FIG. 6 , the first pin of indexing pins  23 A is positioned such that leg member  80 A (or leg  70 A) extends in a direction generally perpendicular to a mounted weapon&#39;s bore axis (e.g. line  101  in  FIG. 5 ) when flared notch  64 A engages the first pin (i.e. pin  23 A- 1  as shown in  FIG. 6 ). Other pins (e.g. pins  23 A- 2 ,  23 A- 3 ,  23 A- 4 , etc.) may be distributed across the circumferential groove of the end of arm  22 A to lock leg member  80 A at different angles depending on which pin flared notch  64 A engages. In the example embodiment shown in  FIG. 6 , pins  23 A are distributed evenly such that the angle between leg member  80 A (or leg  70 A) and a mounted weapon&#39;s bore axis is 90° when flared notch  64 A engages the first pin (i.e. pin  23 A- 1 ), 60° when flared notch  64  engages the second pin (i.e. pin  23 A- 2 ), 30° when flared notch  64  engages the third pin (i.e. pin  23 A- 3 ), and 0° when flared notch  64 A engages the last pin (i.e. pin  23 A- 4 ) (e.g. leg member  80 A is parallel to a mounted weapon&#39;s bore axis). In other embodiments, different angles can be achieved by modifying the distribution and/or number of position pins  23 A. 
     In some embodiments, bipod  100  may be as shown in  FIGS. 7 to 9 . In such embodiments, bipod  100  comprises a base  40 C with a single friction element  44 . Loading an attached weapon (i.e. transitioning base  40 C from a mobile state to a rigid state) frictionally engages friction element  44  with a bottom surface of bracket  20 . Such embodiments, may also comprise, semi spherical shaped feet  90 . Leg cylinders  60  couple leg members  80  to bracket arms  22 . In some such embodiments, friction between bracket arms  22  and cylinders  60  respectively facilitates positioning legs  70  in a plurality of different firing positions. 
       FIG. 10  is a cross-sectional view of base  40 C and bracket  20  corresponding to bipod  100  shown in  FIGS. 7 to 9 . Base  40 C, as shown in  FIG. 10 , is in its neutral state (i.e. base  40 C is pivotally movable relative to bracket  20 ). 
       FIG. 11  is a perspective view of bipod  100  with its legs deployed in an alternative firing position. The toroidal shape of feet  90  allows bipod  100  to stabilize against vertical support surface  200  when legs  70  are propped forward. As previously discussed, friction elements  44 A,  44 B (hidden from view in  FIG. 11 ) may be designed to allow mounted weapon  102  to lock in position at different angles relative to legs  70 . 
       FIG. 12  is a top view illustrating feet  90  of the bipod  100  angled inwards to improve stability according to an example embodiment. In some embodiments, feet  90  may be adjusted to modify the angle between feet lines  95  and the bore axis of a mounted weapon. These adjustments may be made by twisting feet  90  relative to legs  70 , rotating the joint between feet  90  and legs  70 , etc. In some embodiments, feet  90  are non-adjustable. 
     As described elsewhere herein, some embodiments of bipod  100  provide built-in shock and/or vibration isolators and/or shock and/or vibration dampers to reduce disturbances caused by both internally generated shocks and/or vibrations (e.g. movement of the weapon&#39;s mechanism, explosive initiation of the propellant charge by the primer, pressure waves created by the burning propellant inside the bore of a weapon, friction between the accelerating projectile and the bore of a weapon, etc.) and external shocks and/or vibrations (e.g. when shooting from a vehicle or aircraft). For example, friction elements  44 A,  44 B may be made of materials with good shock and/or vibration damping properties (e.g. rubber, polyurethane, etc.) to absorb shocks and/or vibrations transmitted from the weapon and/or reflected back to the weapon through the connection between base  40 A and bracket  20 . Additionally, the coupling mechanism between leg cylinders  60  and shafts  30  (e.g. shafts  30 A,  30 B) may comprise a bushing  35  made from shock and/or vibration damping material (e.g. self-lubricating polymer, vibration damping polymer, etc.). Legs  70  may also comprise outer sleeves  82  made of rubber, polyurethane, or other suitable material with good shock and/or vibration damping properties that fully or partially enclose legs  70  (or leg members  80 ) and dampen shocks and/or vibrations propagating along legs  70  (or leg members  80 ). In preferred embodiments, feet  90  may also be made of a material with good shock and/or vibration damping properties and may dampen shocks and/or vibrations propagating along legs  70  (or leg members  80 ) and/or dampen the effects on bipod  100  of shocks and/or vibrations traveling across a supporting surface. In some embodiments, mounting joint  50  and/or springs  65  may also dampen shocks and/or vibrations propagating through bipod  100 . 
     Bipod  100 , may, for example, be used to stabilize a projectile weapon. Bipod  100  may be removably coupled to a projectile weapon using any method described elsewhere herein. Once the projectile weapon is coupled, frictionally engaging one or more of friction elements  44 A,  44 B with bracket  20  may, for example, stabilize the projectile weapon. Friction elements  44 A,  44 B may be frictionally engaged to bracket  20  using any method described elsewhere herein. Frictions elements  44 A,  44 B may, for example, be frictionally engaged to a bottom surface of platform  21  as described elsewhere herein. 
     In the exemplary embodiments described herein, bases  40 A,  40 B, and  40 C are shown as being coupled below bracket  20 . A person skilled in the art will recognize that bases  40 A,  40 B, and  40 C may, for example, be coupled above bracket  20  (i.e. a bottom surface of base  40 A,  40 B, or  40 C would be frictionally engageable with a top surface of the bracket). A person skilled in the art will recognize that other types bases are available and may be coupled above or below bracket  20 . In some embodiments of the invention, bases  40 A,  40 B, and  40 C may be coupled to bracket  20  in any orientation so long as their surface is frictionally engageable with a surface of bracket  20 . 
     Interpretation of Terms 
     Unless the context clearly requires otherwise, throughout the description and the claims:
         “comprise”, “comprising”, and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”;   “connected”, “coupled”, “attached” or any variant thereof, means any connection, coupling or attachment, either direct or indirect, between two or more elements; the coupling, connection or attachment between the elements can be physical, logical or a combination thereof;   “herein”, “above”, “below”, and words of similar import, when used to describe this specification, shall refer to this specification as a whole, and not to any particular portions of this specification;   “or”, in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list;   the singular forms “a”, “an”, and “the” also include the meaning of any appropriate plural forms.       

     Specific examples of systems, methods and apparatus have been described herein for purposes of illustration. These are only examples. The technology provided herein can be applied to systems other than the example systems described above. Many alterations, modifications, additions, omissions, and permutations are possible within the practice of this invention. This invention includes variations on described embodiments that would be apparent to the skilled addressee, including variations obtained by: replacing features, elements and/or acts with equivalent features, elements and/or acts; mixing and matching of features, elements and/or acts from different embodiments; combining features, elements and/or acts from embodiments as described herein with features, elements and/or acts of other technology; and/or omitting combining features, elements and/or acts from described embodiments.
         It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, omissions, and sub-combinations as may reasonably be inferred. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.