FIREARM SUPPORT SYSTEM WITH INDEPENDENT CANT ADJUSTMENT AND LEVEL INDICATOR
The present disclosure relates to a firearm support, comprising a main body assembly, at least two legs operably attached to the main body assembly, a mounting assembly comprising an attachment mechanism configured to enable attachment of a firearm to the mounting assembly and a swivel mechanism configured to control an angular rotation about a swivel axis; and a cant mechanism configured to control an angular rotation about a cant axis by rotating the mounting assembly along an opening in the main body assembly, whereby cant angle may be locked and remain constant as an attached firearm swivels.
This disclosure relates to firearm supports, and, more particularly, to bipods enabling independent cant and swivel adjustments and level measurement capabilities.
BACKGROUND OF THE INVENTIONIn a typical mid to long range shooting application, a firearm may be equipped with an optical sighting device (i.e. a sight or scope) mounted above the rifle's bore.
To reach long distance targets, elevation compensation is used to counteract the gravitational pull of the Earth on a projectile. As depicted in
Before proceeding, it is worth noting that when a scope is mounted on a rifle it is almost always mounted parallel to the bore of the firearm, however, in
In regards to determining the correct holdover angle β, the holdover angle β is determined through a two-step process. The first step is to set the holdover angle β so that the bullet trajectory intersects the line of sight at a specific distance (100 yards for instance). When the holdover angle is so adjusted, the rifle bore and sight are said to be “zeroed” for that distance.
The second step is only necessary if the target is not at the zeroed distance. This step requires the rifleman to use a table, which is often referred to as a “drop table,” to determine the final adjustment to the holdover angle β. A typical drop table lists the height of a bullet above or below the line of sight as a function of the distance to the target. A drop table may be generated empirically at a rifle range; calculated using a ballistic simulator; or provided by ammunition manufacturers. Drop values are calculated under the assumption that the rifle has been zeroed at a specific distance at which the drop value is zero. Even for the same firearm, drop tables are specific to several parameters including bullet weight, bullet shape, cartridge powder load, primer used, barrel length, wind speed, direction and other variables.
Problematically, these adjustments and calculations assume that the rifle is held perfectly vertical. A significant problem is induced if a rifle is fired when the rifle plane, which is the plane that includes the line of sight and the bore axis, is not in the vertical plane, defined as the plane including the line of sight and a line from the center of the earth to the end of the rifle's bore. The angle between the rifle plane and vertical planes is referred to as the cant angle; when the cant angle (α) is not zero: this is called cant error. Since a shooter's eye is the point of reference, when the rifle plane is not in the vertical plane i.e. when a rifle is held canted, the rifle's bore rotates around the line of sight while the relationship between the sighting device and the barrel does not change.
Cant modifies the impact point of a projectile, creating a windage error Δx (horizontal component) and an elevation error Δy (vertical component). In the example depicted in
As a first approximation, the windage, or horizontal, error (Δx) is directly proportional to the distance to the target, to α and to β. The windage error Δx is approximately 3 cm per degree of α per degree of β and per 100 m of distance to the target. For example, at 500m, with β=0.2 degrees (typical of a high-velocity 5.56 mm bullet at that distance) Δx is approximately 3 cm per degree of cant.
This numerical example shows that at long range, even small deviations from a vertical hold significantly affect the impact point of a projectile. This windage error is subject to a compound effect when the distance to the target increases or when using a lower velocity round, as β itself increases with increasing distance and lower projectile velocity, since greater elevation compensation is needed in both situations to account for the longer period on which gravity will act on the projectile prior to impact with the target.
The windage error becomes an order of magnitude larger when shooting at an elevated target. With the previous example, at 500 m, shooting at a target just 2 degrees above the shooter, a single degree of cant induces a windage error Δx of approximately 30 cm.
Another issue faced by long-distance riflemen is that, in real life situations, there is typically no reference to the true horizon. If the shooter is on uneven ground and/or is aiming towards a non-horizontal background, the human physiology is not able to determine the position of the vertical plane with any degree of precision and significant unintentional canting of the rifle is to be expected.
Furthermore, when it is a shooter's intent to track a moving target, the shooter would, ideally, in a first step adjust the cant angle to adapt to the conditions of the terrain where the bipod is standing and in a second step allow the rifle to swivel to track the target. Such swivel/tracking functionality would ideally be such that it does not induce cant error when used.
Classic bipods do not allow for cant angle adjustment, their legs are either in a stored or deployed orientation. Often, such legs are telescopic. Other bipods offer only cant adjustment.
There are, however, bipods available that offer adjustment of cant and swivel angles, however, these angles may not be adjusted independently in the majority of such designs. Typical designs include a ball and socket joint whereby cant and swivel are adjusted simultaneously. This means that if a shooter attempts to track a target (swiveling) it is likely that the cant angle will be simultaneously modified.
Still other designs allow for cant and swivel angles to be independently adjusted. In such designs, however, once the cant angle has been adjusted, subsequent use of the swiveling functionality will modify the cant angle if the legs are not in the horizontal position, inducing cant error. Furthermore the cant adjustment mechanism of such designs relies on an unstable equilibrium concept: if loosened, gravity will cause the firearm being supported to tilt or fall to the side. A different design with a stable equilibrium would allow the mechanism to tend towards the vertical position on its own, stay there without requiring the user to exert strong force until the cant position is secured, and make it significantly easier to make one handed cant adjustments, even in prone position.
What is needed, therefore, are techniques for enabling a user to readily determine if a rifle is canted and to set a cant angle while allowing for swiveling and target tracking without impacting cant angle adjustment.
SUMMARY OF THE INVENTIONIt is an object of the present invention to provide a mechanism for tracking/swiveling movement without changing the cant angle.
It is another object of the present invention to provide a means of determining the cant angle, specifically in a way that is visible by the operator while adjusting the cant angle.
One embodiment of the present invention provides a firearm support, comprising: a main body assembly, at least two legs operably attached to the main body assembly, a mounting assembly comprising an attachment mechanism configured to enable attachment of a firearm to the mounting assembly, a cant guide projection comprising two concentric surfaces, and a swivel mechanism configured to control an angular rotation about a swivel axis, and a cant mechanism configured to control an angular rotation about a cant axis by rotating the mounting assembly along an opening in the main body assembly comprising two concentric surfaces co-concentric with the cant guide projection concentric surfaces.
Another embodiment of the present invention provides such a firearm support wherein the at least two legs are each operably attached to the main body assembly by an indexer assembly configured to control an angular rotation of the at least two legs about the main body assembly.
A further embodiment of the present invention provides such a firearm support wherein the at least two legs each comprise a telescoping assembly operable to extend and retract the at least two legs.
Yet another embodiment of the present invention provides such a firearm support wherein each telescoping assembly further comprises a catch channel disposed on the inner leg and a catch screw extending through the outer leg and operable to engage the catch channel.
A yet further embodiment of the present invention provides such a firearm support further comprising a cant locking mechanism comprising a locking plate and a threaded element such as a thumb screw or a locking lever operable to clamp the main body between the locking plate and the threaded element.
Still another embodiment of the present invention provides such a firearm support wherein the locking plate includes a level indicator.
A still further embodiment of the present invention provides such a firearm support wherein the threaded element is captive.
Even another embodiment of the present invention provides such a firearm support wherein the swivel mechanism comprises a first plate that stays fixed in relation to the firearm, a second plate configured to rotate parallel to the first plate around the swivel axis and a swivel locking assembly configured to move between a swivel locked position and a swivel unlocked position.
An even further embodiment of the present invention provides such a firearm support wherein the swivel mechanism comprises a means to limit the angular rotation of the second plate around the swivel axis.
A still even another embodiment of the present invention provides such a firearm support wherein the attachment mechanism comprises a mounting base having a rail-engaging clamp member and at least one locking lever being mounted to the mount base and being moveable to a clamping position, whereby clamping engagement with the mount rail is established, and to a released position, whereby clamping engagement with the mount rail is released.
A still even further embodiment of the present invention provides such a firearm support wherein each of the at least two legs further comprises a removable support foot attached to the outer leg.
One embodiment of the present invention provides a firearm support comprising a main body assembly, two legs operably attached to the main body assembly, a mounting assembly, a cant mechanism operable to control an angular rotation about a cant axis and to lock the position of the mounting assembly in a desired position relative to the ground and a swivel mechanism operable to control an angular rotation about a swivel axis, wherein the swivel mechanism can always be operated in such a way that the swivel axis remains perpendicular to the cant axis as the firearm swivels.
One embodiment of the present invention provides a firearm support comprising a cant mechanism operable to control an angular rotation about a cant axis and a swivel mechanism operable to control an angular rotation about a swivel axis, wherein the cant axis is substantially concentric with a bore of a firearm to which the firearm support is attached.
One embodiment of the present invention provides a firearm support comprising a cant mechanism operable to control an angular rotation about a cant axis and a swivel mechanism operable to control an angular rotation about a swivel axis, wherein the cant mechanism is located below the swivel mechanism.
One embodiment of the present invention provides a firearm support comprising a main body assembly, a mounting assembly, wherein the mounting assembly comprises an attachment mechanism operable to attach a firearm to the mounting assembly, a cant mechanism operable to control an angular rotation about a second axis, wherein the cant mechanism is created by rotating the mounting assembly along an opening in the main body assembly, whereby swivel and cant may be adjusted independently, and at least two legs operably attached to the main body assembly; wherein the at least two legs are each operably attached to the main body assembly by an indexer assembly configured to control an angular rotation of the at least two legs about the main body assembly; and wherein each indexer assembly comprises a spring loaded button that allows the leg to be released from its indexed position, and wherein the button can be pushed to release the indexed position.
One embodiment of the present invention provides a firearm support comprising a main body assembly, at least two legs operably attached to the main body assembly; wherein the at least two legs each comprise a telescoping assembly operable to extend and retract the at least two legs, and wherein each telescoping assembly comprises an outer leg further comprising an opening that is perpendicular to the outer leg axis, an inner leg at least partially disposed within the outer leg and operable to extend and retract relative to the outer leg, and comprising a plurality of notches disposed about the inner leg and a spring loaded release button disposed around the inner leg, wherein the release button only protrudes from the outer leg, if at all, through the outer leg opening; and wherein the release button is operable to slide within at least one of the plurality of notches so as to block the movement of the outer leg in relation to the inner leg, or when depressed to slide out of the notches so as to allow the outer leg to extend and retract relative to the inner leg.
Another embodiment of the present invention provides such a firearm support wherein the release button does not protrude from the outer leg.
A further embodiment of the present invention provides such a firearm support wherein each of the at least two legs further comprises a removable support foot attached to the outer leg.
Yet another embodiment of the present invention provides such a firearm support wherein each of the removable support foot is contained in the cylinder defined by the outer leg envelope.
One embodiment of the present invention provides a firearm support comprising a main body assembly, at least two legs operably attached to the main body assembly, a cant mechanism operable to control an angular rotation about a cant axis and a level indicator.
Another embodiment of the present invention provides such a firearm support wherein the level indicator comprises a ball guided in a cavity filled with a liquid.
A further embodiment of the present invention provides such a firearm support wherein the ball is guided between at least two surfaces, two of which are concentric with the cant axis.
Yet another embodiment of the present invention provides such a firearm support further comprising a swivel mechanism operable to control an angular rotation about a swivel axis.
One embodiment of the present invention provides a method for adjusting the cant and swivel of a bipod mounted device when tracking a target comprising providing a bipod mounting assembly comprising: first and second extendable legs; the bipod mounting assembly including a cant control mechanism controlled using a first control knob; the bipod mounting assembly further comprising a swivel control mechanism controlled using a second control knob, the swivel control mechanism being independent of the cant control mechanism; grasping the bipod mounted device and placing the first and second extendable legs against a supporting surface; aiming the bipod mounted device to orient the bipod mounting assembly at a selected cant angle or angle relative to a vertical plane, preferably in the vertical plane, and locking such cant angle using the first control knob; unlocking the swivel control mechanism using the second control knob; and aiming the bipod mounted device at the target.
The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.
For a rifle equipped with a sighting device we define:
-
- The bore axis as the axis of the rifle's bore;
- The line of sight as the straight line from the reticle of the sighting device to the target;
- The holdover angle β as the angle between the bore axis and the line of sight;
- The rifle plane as the plane including the line of sight and the bore axis;
- The vertical plane as the plane including the line of sight and the line from the center of the earth to the end of the rifle's bore; and
- The cant angle α as the angle between the vertical plane and the rifle plane.
The present disclosure provides bipods intended to be mounted to a rail platform, which allow for determining and setting of a cant angle while allowing for the rifle to be swiveled without affecting the cant angle, allowing for accurate target tracking at a long distance.
The bipods of the present disclosure provide a cant mechanism created by the interaction between a main body assembly 200 and a mounting assembly 100.
Now referring to the cant angle lock mechanism with captive thumb screw, as depicted in
When the user of such an embodiment has selected a cant angle, such angle, in embodiments, may be locked by clamping main body assembly surfaces 214 between the clamp surface 125 and cant locking plate 130 of mounting assembly 100 using cant locking thumb screw 140. A cant guide projection 122 may include a non-threaded opening 122C guiding cant locking thumb screw 140 (See
In
Cant locking plates 130 and 130L, in embodiments, have a threaded hole 131C so as to host a set screw 150 (see
Embodiments of the present disclosure may further incorporate a swivel mechanism. Such a mechanism may be a part of mounting assembly 100. As shown in
The swivel friction force, in embodiments, may be adjusted by varying the torque applied to screw 128.
The swivel angle, in embodiments may be limited to a predetermined range, for instance by adding a tab to the inside wall of cylinder 123 and a corresponding recess to cylinder cavity 112 (not shown). Since the swivel angle is limited by interference with main body assembly 200, a limitation of the swivel range within mounting assembly 100 is not necessary.
The swivel mechanism is completely independent from the cant mechanism.
A most important feature of the aforementioned cant angle adjustment mechanism is that once the cant angle is adjusted to zero, mounting assembly 100 is horizontal. Therefore, the swivel mechanism allows for tracking of a target while keeping the firearm in the vertical plane, thus avoiding the creation of cant error.
It is therefore important and beneficial to have the following mechanical sequence: firearm—mounting mechanism—swivel mechanism—cant mechanism—legs instead of firearm—mounting mechanism—cant mechanism—swivel mechanism—legs.
Still other embodiments of the present disclosure incorporate a swivel lock assembly. A swivel lock assembly, in embodiments, comprises a swivel locking knob 160, a swivel lock screw 170, a swivel lock spring 180 (see
The swivel locking knob 160, in embodiments, has a locking projection 162 that is configured to sink into swivel locking knob cavity 121.
In
In
Further embodiments of the present disclosure incorporate rail mounting mechanisms, such as quick disconnects and permanent clamps, for mounting the bipod of the present disclosure to a firearm.
Firearms such as M-16/AR-15/M4 and other long range rifles often feature accessory mounting rails positioned below, above and/or on the sides of the barrel. Such a rail may include a number of mounting projections interleaved with a series of grooves, and these mounting projections and grooves may be employed to associate the accessory with the rail. Rails usually conform to certain standards. For example, two common rails include the “Picatinny” MIL-STD 1913 rail and the “Weaver” rail, both include interleaved mounting projections and grooves, but differ in their dimensions. Other rail types, such as the “keymod” rail exist and one of ordinary skill in the art would be able to readily adapt the invention of the present disclosure to such an alternative rail system.
Firearm accessories have historically been mounted by means of mounting screws. This is typically referred to as a permanent mount since the accessory will typically remain assembled to the firearm until the end of a mission. Because various missions often require a different set of accessories, and because field modification of weapon configurations can be critical in combat situations, there is a need for versatile and reliable quick-disconnect (QD) attachment mechanisms, also known as “throw lever” mechanisms. We present here two means of attachment to a mounting rail 400 featuring four oppositely angulated clamping surfaces 401.
Although rail mounting systems are extensively discussed and have many desirable attributes when used in conjunction with embodiments of the present disclosure, the scope of this disclosure should not be limited to rail mounting solutions. Methods of mounting an accessory to firearms not equipped with such rails are well known to those having ordinary skill in the art.
Now referring to
In embodiments, a leg may be locked when 350 is positioned in one of the cavities 222 and spring 370 biases 350 outwards, as shown in
Rotation knob may further comprise an opening 352. This opening 352, in embodiments, is configured to allow inner leg 310 to rotate when a user presses on 350.
Inner leg 310, in embodiments, may also comprise a forked end 312. In such an embodiment, pin 240 is secured into inner leg 310 and goes through a pivot plate 220, providing an axis of rotation for inner leg 310. Alternatively, pin 240 could be a screw and a nut.
Now referring to
Now referring to
Now referring to
Embodiments of the present invention further comprise a level or cant indicator. Such embodiments include a cant guide projection 122, which includes two guide holes 122B (see
In embodiments, vial housing 134 may also feature a track 134B to house a compression ring (not shown) to prevent the aforementioned liquid from leaking.
Alternatively, vial housing 134 and vial cover 136 can be replaced by a unitary glass vial.
In embodiments, vial cover 132 further comprises an opening 132A so as to allow a user to ascertain the position of ball 138. Vial cover 132 may also comprise angular markings 132B, enabling direct reading of the cant angle, preferably with each dot representing 1 degree of cant.
Further embodiments, as shown in
Combining a low profile leg extension knob 330A and angled foot 380 allows the device to provide a streamlined leg design, where nothing protrudes from the envelope of the outer leg cylinder.
The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.
Claims
1. A firearm support, comprising:
- a main body assembly;
- at least two legs operably attached to said main body assembly;
- a mounting assembly comprising an attachment mechanism configured to enable attachment of a firearm to said mounting assembly, a swivel mechanism configured to control an angular rotation about a swivel axis, and at least one cant guide projection comprising concentric surfaces; and
- a cant mechanism configured to control an angular rotation about a cant axis by rotating said mounting assembly along at least one surface of said main body assembly that is co-concentric with said cant guide projection concentric surfaces.
2. The firearm support of claim 1, wherein said at least two legs are each operably attached to said main body assembly by an indexer assembly configured to control an angular rotation of said at least two legs about said main body assembly.
3. The firearm support of claim 1, wherein said at least two legs each comprise a telescoping assembly operable to extend and retract said at least two legs.
4. The firearm support of claim 3, wherein each telescoping assembly has a plurality of indexed positions.
5. The firearm support of claim 1, further comprising a cant locking mechanism comprising a locking plate and a threaded element such as a thumb screw or a locking lever operable to clamp said main body between said locking plate and said mounting assembly.
6. The firearm support of claim 5, wherein said locking plate includes a level indicator.
7. The firearm support of claim 5, wherein said threaded element is captive.
8. The firearm support of claim 1, wherein said swivel mechanism comprises a first plate that stays fixed in relation to said firearm, a second plate configured to rotate parallel to said first plate around said swivel axis and a swivel locking assembly configured to move between a swivel locked position and a swivel unlocked position.
9. The firearm support of claim 8, wherein said swivel mechanism comprises a means to limit the angular rotation of said second plate around said swivel axis.
10. The firearm support of claim 1, wherein said attachment mechanism comprises a mounting base having a rail-engaging clamp member and at least one locking lever being mounted to said mount base and being moveable to a clamping position, whereby clamping engagement with said mount rail is established, and to a released position, whereby clamping engagement with said mount rail is released.
11. The firearm support of claim 1, wherein each of said at least two legs further comprises a removable support foot attached to said outer leg.
12. A firearm support, comprising:
- a cant mechanism operable to control an angular rotation about a cant axis; and
- a swivel mechanism operable to control an angular rotation about a swivel axis;
- wherein said cant mechanism is independent of said swivel mechanism and is located below said swivel mechanism.
13. A firearm support, comprising:
- a main body assembly;
- a mounting assembly comprising an attachment mechanism operable to attach a firearm to said mounting assembly and a swivel mechanism configured to control an angular rotation about a swivel axis;
- a cant mechanism operable to control an angular rotation about a cant axis, wherein said cant mechanism is created by rotating said mounting assembly along at least one opening in said main body assembly, whereby swivel and cant may be adjusted independently; and
- at least two legs operably attached to said main body assembly; wherein said at least two legs are each operably attached to said main body assembly by an indexer assembly configured to control an angular rotation of said at least two legs about said main body assembly; and wherein each indexer assembly comprises a spring loaded button that allows said leg to be released from its indexed position, and wherein said button can be pushed to release said indexed position; and
- wherein said at least two legs each comprise a telescoping assembly operable to extend and retract said at least two legs, wherein each telescoping assembly has a plurality of indexed positions.
14. A firearm support, comprising:
- a main body assembly;
- at least two legs operably attached to said main body assembly; wherein said at least two legs each comprise a telescoping assembly operable to extend and retract said at least two legs, and wherein each telescoping assembly comprises an outer leg further comprising one or two button openings that are perpendicular to the outer leg axis and concentric to each other, an inner leg at least partially disposed within said outer leg and operable to extend and retract relative to said outer leg, said inner leg to comprising a plurality of indexing notches; and
- a spring loaded release button assembly disposed through said button openings, wherein said release button assembly only protrudes from said outer leg, if at all, through said outer leg button openings; and wherein said release button is operable to slide within at least one of said plurality of indexing notches so as to block the movement of said outer leg in relation to said inner leg, or when depressed to slide out of said notches so as to allow said outer leg to extend and retract relative to said inner leg.
15. The firearm support of claim 14, wherein each of said at least two legs further comprises a removable support foot attached to said outer leg.
16. A firearm support, comprising:
- a main body assembly;
- at least two legs operably attached to said main body assembly;
- a cant mechanism operable to control an angular rotation about a cant axis; and
- a level indicator.
17. The firearm support of claim 16, wherein said level indicator comprises a ball guided in a cavity filled with a liquid, wherein said ball is guided between at least two surfaces, two of which are concentric with said cant axis.
18. The firearm support of claim 16, further comprising a swivel mechanism operable to control an angular rotation about a swivel axis.
Type: Application
Filed: Jan 16, 2016
Publication Date: Jul 21, 2016
Inventor: Mr. Remy Trotabas (Chester, NH)
Application Number: 14/997,525