Accessory mounting hand guard for firearm

Hand guards for firearms and related methods are provided. In one example, a hand guard includes an elongated housing. The elongated housing comprises a lumen configured to substantially surround an intermediate portion of a barrel of a firearm, a lateral side wall, and a pair of inclined side walls respectively disposed on opposite sides of and inclined relative to the lateral side wall. Each of the inclined side walls comprises an elongated slot, wherein the elongated slots of the inclined side walls define a pair of angulated faces of a rail adapted to receive an accessory to be mounted thereon. For example, the rail may be a reduced-height Picatinny rail provided by the lateral side wall of the housing.

BACKGROUND

1. Technical Field

This invention relates to firearms in general, and in particular, to hand guards for firearms that enable various accessories to be mounted thereon reliably and efficiently.

2. Related Art

Firearms, such as the M16 and M4 rifles adopted for use by the U.S. military services, typically incorporate a hand guard made of a plastic or composite material, by which the shooter can effectively grasp a forward portion of the barrel of the weapon, e.g., for carrying, aiming and shooting the weapon effectively. Additionally, it is recognized that such firearms can often benefit from a variety of shooting accessories coupled to the weapon, such as lights for illuminating targets or sighting devices, e.g., laser targeting devices. Responsively, the prior art is replete with examples of devices, including hand guards adapted to replace the stock hand guard provided on the rifle, that are designed to enable one or more accessories to be coupled to the weapon.

However, these prior art devices and hand guards are not free of problems. For example, some rely on complicated mechanisms for coupling the hand guards to the rifle that can result in an unreliable mounting of the hand guard on the rifle, typically accompanied by a lengthy amount of time needed to mount the hand guard on the weapon. In other instances in which the hand guard mounts on the barrel of the rifle, the forces applied to the barrel in mounting the hand guard to it can twist or deform the barrel such that the accuracy of the rifle is adversely affected.

Accordingly, a need exists for hand guard designs that enable a variety of useful accessories to be mounted on a firearm, together with methods for mounting the hand guards on the firearm quickly, reliably and without adversely affecting their accuracy.

SUMMARY

In accordance with various embodiments described herein, hand guards that permit a variety of useful accessories to be mounted on firearms are provided, together with methods for mounting the hand guards on the firearms quickly, reliably and without adversely affecting their accuracy.

In one embodiment, a hand guard for a firearm, such as a rifle, includes an elongated tubular housing comprising an upper part, a lower part, opposite open ends, and an elongated lumen configured to receive an intermediate portion of a barrel of a firearm longitudinally therein. An expansion collar is disposed at one end of the housing. The expansion collar includes an expansion mechanism configured to adjustably compress the expansion collar and the lower part of the housing longitudinally between a pair of surfaces respectively disposed at opposite ends of the intermediate portion of the barrel.

In another embodiment, a method for using a hand guard with a firearm comprises providing an elongated tubular housing comprising an upper part, a lower part, opposite open ends, and a lumen configured to receive an intermediate portion of a barrel of the firearm longitudinally therein. An expansion collar is also provided. The collar has a longitudinally extending tongue and an expansion mechanism configured to adjustably compress the expansion collar and the lower part of the housing longitudinally between a pair of surfaces respectively disposed at opposite ends of the intermediate portion of the barrel. The tongue of the collar is inserted into an end of the housing to form an assembly, and the assembly is mounted onto a lower surface of the intermediate portion of the barrel and between the surfaces thereon. The expansion mechanism of the collar is then adjusted such that the assembly is held in compression between the surfaces.

In another embodiment, a hand guard includes an elongated housing. The elongated housing comprises a lumen configured to substantially surround an intermediate portion of a barrel of a firearm, a side wall, and a pair of elongated slots disposed on opposite sides of the side wall. Each of the elongated slots defines a corresponding angulated face of a rail adapted to receive an accessory to be mounted thereon. For example, the rail may be a reduced-height Picatinny rail provided by the side wall of the housing.

In another embodiment, a method includes inserting at least a portion of an expansion collar into an end of a part of a housing to form an assembly; positioning the assembly over an intermediate portion of a barrel of a firearm and between opposing surfaces thereon; and adjusting an expansion mechanism of the expansion collar such that the assembly is held in compression between the opposing surfaces by advancing a plurality of longitudinally extending screws respectively received in corresponding ones of a plurality of bores contained in the expansion collar such that a distal end of each screw is disposed in abutment with a bottom end surface of a corresponding one of the bores and at least a portion of each screw is loaded in compression.

DETAILED DESCRIPTION

FIG. 1Ais left side elevation view of an example firearm, namely, an M-16 rifle10, of a type with which embodiments of the novel hand guard of the present disclosure can be advantageously utilized. The M16, and a variant thereof, viz., the M4, has generally replaced the M14 and M1 carbine as the standard infantry rifles of the U.S. armed forces. Currently, the M16 is the most commonly manufactured 5.56×45 mm rifle in the world, and is in use by 15 NATO countries and more than 80 countries worldwide. Numerous companies in the United States, Canada, and China have, together, produced more than 8,000,000 M-16 rifles, in all of its many variants, of which approximately 90% are still in operation.

As can be seen inFIG. 1A, the example rifle10includes a receiver12having a combined carrying handle and rear sight14, a rear or shoulder stock16extending rearwardly from the receiver12, a pistol-type hand grip18, a trigger20for firing the rifle10, a magazine22for holding ammunition, an elongated barrel24extending forwardly from the receiver12, an upstanding front sight26mounted forwardly on the barrel24, and a longitudinal axis28concentric with the barrel24. Extending rearwardly from the front sight26to the receiver12is a gas tube30that conveys combustion gases from a port (not seen inFIG. 1A) in the barrel24located below the front sight26to the receiver12, which are used by components in the receiver for the automatic actuation of the rifle10when it is fired.

The example rifle10also conventionally includes a hand guard, typically made of a plastic composite, that surrounds the gas tube30and an intermediate portion32of the barrel24. However, inFIG. 1A, the conventional hand guard has been omitted for purposes of explication. As illustrated inFIG. 1A, the intermediate portion32of the barrel24includes a pair of front and rear radial surfaces34and36respectively disposed at opposite ends thereof. The front radial surface34comprises the rear surface of a hand guard forward support cap38, and the rear radial surface36comprises the front surface of a threaded hand guard rear slip ring retainer40(also referred to as a barrel nut). As discussed in more detail below, the two radial surfaces34and36disposed at the opposite ends of the intermediate portion32of the barrel24can, in some embodiments, provide features that are advantageous for mounting a hand guard100in accordance with the present disclosure on the rifle10.

FIG. 1Bis an upper, front, left side perspective view of the receiver12and barrel24of the rifle10ofFIG. 1A, showing a first example embodiment of a hand guard100in accordance with the present disclosure mounted thereon.FIGS. 2 and 3are upper, front, left side perspective and exploded perspective views of the example hand guard100, respectively. As illustrated inFIGS. 2 and 3, the example hand guard100comprises an elongated tubular housing102having an upper part104, a lower part106, opposite open ends108and110, and a lumen112configured to receive the gas tube30and intermediate portion32of the barrel24of the firearm10longitudinally therein.

As illustrated in the cross-sectional view of the housing102inFIG. 6, the housing102can have a generally polygonal cross-section, and in the particular embodiment illustrated, the housing102has eight side walls, i.e., is octagonal in cross-sectional shape. Other cross-sectional shapes, including round or annular, can also be used. At least one of the side walls of the housing102can comprise a longitudinal accessory mounting rail113, such as specified in MIL-STD-1913 and commonly referred to as a “Picatinny” rail, or other type of rail. In the particular example embodiment illustrated inFIG. 6, four such accessory mounting rails113are provided, disposed in alternating fashion around the circumfery of the housing102, one comprising the top side wall of the upper part104of the housing102, and three comprising the two lateral and one bottom side walls of the lower part106thereof.

As shown inFIG. 1B, when hand guard100is installed on receiver12, a top rail113on upper part104may be substantially level with another rail170(e.g., another longitudinal accessory mounting rail such as another Picatinny rail or other type of rail). Such positioning of rails113and170may advantageously permit various accessories to be mounted substantially in line with each other on rails113and170and/or permit such accessories to be mounted across both rails113and170(e.g., using mounting locations of both rails113and170).

One or more accessories many be mounted on rails113such as, for example, lighting devices, sighting devices, and/or others. For example, as identified inFIG. 3, a lighting device190(e.g., a SureFire Scout Light in one embodiment) may be provided to be mounted on rails113(e.g., directly and/or with a rail clamp192, such as a SureFire M93 Swing-Lever WeaponLight Rail Clamp in one embodiment and/or as identified in U.S. Pat. No. 8,127,484 which is hereby incorporated by reference in its entirety).

In some embodiments, upper part104may include one or more protrusions182(e.g., one or more flanges or individual protruding members) configured to engage or contact receiver12(seeFIGS. 1B and 3). For example, protrusion182may extend over, rest upon, and/or push against various external portions of retainer40and/or of rear sight14. In some embodiments, lower part106may include one or more protrusions180(e.g., implemented as one or more flanges or individual protruding members) configured to engage or contact receiver12(seeFIGS. 1B and 3). For example, protrusions180may rest upon and/or push against retainer40. In various embodiments, protrusions180and/or flanged portion182may be used to further secure hand guard100to rifle10.

As illustrated inFIGS. 2,3,8, and9, the example hand guard100further comprises an expansion collar114disposed at one end of the housing102. The expansion collar114incorporates an expansion mechanism, described below, configured to adjustably compress the expansion collar114and the lower part106of the housing102longitudinally between the radial surfaces34and36located at opposite ends of the intermediate portion32of the barrel24, as described above. In the particular embodiment illustrated in the figures, the expansion collar114is shown disposed adjacent to the front end108of the housing102, but as those of some skill in the art will appreciate, this arrangement can be reversed, such that the expansion collar114is disposed adjacent to the rear end110of the housing102.

Additionally, as illustrated in, e.g.,FIGS. 2,3,7A,7C, and7D, the expansion collar114can include a longitudinal tongue116that can be slid into a complementary recess in the adjacent open ends108or110of the housing102to generally align the collar114concentrically with the housing102and the lumen112thereof.

As illustrated in, e.g.,FIGS. 2,3and8, in one embodiment, the expansion mechanism can comprise a plurality, e.g., two or more, of longitudinally extending screws118(e.g., also referred to as jack screws) respectively received in corresponding ones of a plurality of threaded apertures120contained in the expansion collar114. Each screw118has a distal end122that can be urged into abutment with an adjacent end,108or110of the lower part106of the housing102. In some embodiments, the end108or110of the housing102, against which the distal ends122of the screws118bear, can be protected against any resultant deformation and wear caused by abutment of the screw ends122by the provision of a corresponding plurality of wear pads124made of, e.g., a hard metal, disposed in corresponding, complementary recesses126in the adjacent end of the lower part106of the housing102. The distal ends112of the screws118can then respectively bear on the pads124with virtually no resulting wear or deformation of the adjacent end of the lower part106of the housing. In addition, as screws118are tightened, the longitudinal expansion of hand guard100may cause protrusions180to push against retainer40and thus tighten end110of hand guard100against rifle10.

As illustrated in, e.g.,FIGS. 3 and 9, in some embodiments, the expansion mechanism can further include a plurality of elongated compression members128that extend longitudinally from an end of the expansion collar114opposite to the end of the housing102at which the expansion collar114is disposed. As illustrated inFIG. 9, the compression members128can include a first end portion130that can comprise a material that may compress and expand (e.g., being at least partially deformable, compressible, and/or expandable) while still remaining relatively resilient, such as rubber or polyurethane, which is disposed in a corresponding bore132(seeFIG. 7B) in the expansion collar110, and an opposite second end134comprising a relatively harder bearing material, e.g., a metal, such as steel.

In some embodiments, the example hand guard100can be mounted on an associated rifle10in accordance with the following example mounting method, in which it is assumed that the expansion collar114is mounted at the front end108of the housing102and disposed adjacent to the front radial surface34, as illustrated in the example embodiment ofFIGS. 1A and 1B.

First, the upper part of the housing102is removed from the lower part106, which can be effected in a manner described in more detail below. The longitudinal tongue116of the expansion collar114is inserted into the front end108of the lower part106of the housing102to form a loose assembly therewith. The assembly of the expansion collar114and lower part106of the housing102is then mounted onto the lower surface of the intermediate portion32of the rifle barrel24and between the radial surfaces34and36disposed at the opposite ends thereof, i.e., with the compression members128of the expansion collar114disposed adjacent to the front radial surface34and the rear end110of the lower part106of the housing102disposed adjacent to the rear radial surface36. In one embodiment, the assembly of the expansion collar114and lower part106of the housing may be positioned around (e.g., without touching) the intermediate portion32of the rifle barrel24and rotated thereabout until the lower part106of the housing102is disposed beneath the rifle barrel24.

As illustrated inFIG. 8, the screws118are then advanced in their respective threaded apertures120in the expansion collar114such that the distal end122of each screw118engages a corresponding pad124in the adjacent end of the lower part106of the housing102. As indicated by the arrows136inFIGS. 8 and 9, further advancement of the screws118causes the lower part102and expansion collar114to spread apart from each other, thereby loading the entire longitudinal assembly comprising the compression members128, the expansion collar114, and the lower part106of the housing102, in compression between the two radial surfaces34and36, thereby firmly coupling the longitudinal assembly firmly to the rifle10.

As those of some skill will appreciate, this compressive force results in a reactive longitudinal tensile force being applied to the barrel24of the rifle10, which, unlike various prior hand guards, does not result in any twisting or local deformations of the barrel24, and therefore does not adversely affect the accuracy of the rifle10. Any differences in the respective forces exerted by the screws118are taken up by the plurality of compression members128, which compress or expand locally (e.g., performed by the material of first end portion130) to ensure that the force exerted by the screws118is substantially uniformly distributed among the compression members and on the adjacent end of the lower part106of the housing102. although such compression and expansion is described as being performed by the material of first end portion130of compression members128, such material may be provided by any component of hand guard100. For example, in one embodiment, such material may be provided as part of screws118and/or other components adapted to compress and expand between end108and surface34.

One of the many advantages provided by embodiments of the first example hand guard100of the present disclosure is that the upper part104of the housing102can be removed from the lower part106of the housing102, e.g., to gain access to the gas tube30and/or the intermediate portion32of the barrel24, without having to remove the lower part106and expansion collar114from the rifle10. As illustrated in, e.g.,FIGS. 3 and 6, this can be effected by the provision of a coupling mechanism for releasably coupling the upper part104of the housing102to the lower part106thereof. Moreover, the lower part106may remain tightly engaged with surfaces34and36(e.g., by longitudinal expansion) while the upper part104is removed. As a result, accessories installed onto lower part106may remain attached and in alignment while the upper part104is removed. Also, accessories installed onto upper part104may also remain attached and in alignment while the upper part104is removed. Therefore, if upper part104is subsequently attached to lower part106, all accessories attached to hand guard100may be aligned and ready for use without requiring further adjustment by the user.

In other embodiments, the locations and/or configurations of upper part104and/or lower part106may be changed. For example, in one embodiment, the locations of upper part104and lower part106may be reversed such that upper part104is actually positioned below lower part106while hand guard100is installed on intermediate portion32of barrel24. In such an embodiment, upper part104may be lowered downward from rifle10(e.g., lowered down on the trigger side of rifle10) while lower part106remains installed (e.g., positioned on a top side of rifle10and straddling intermediate portion32of barrel24).

As illustrated in, e.g.,FIGS. 3,5C, and5E, the upper part104of the housing102can include a pair of laterally spaced, downwardly extending side walls138, each having a lower edge140and a generally planar exterior surface142. As illustrated in, e.g.,FIGS. 3 and 6, the lower part106of the housing102can have a pair of laterally spaced, upwardly extending side walls141, each of which has a generally planar interior surface144, with a ledge146disposed at a lower edge thereof. As illustrated inFIG. 6, the side walls138of the upper part104are positionable inside the side walls141of the lower part106such that respective ones of the planar exterior surfaces142of the side walls138of the upper part104are disposed in facing opposition to corresponding ones of the planar interior surfaces144of the side walls141of the lower part102. As illustrated in, e.g.,FIGS. 3,4B,4D and6, the coupling mechanism can comprise a plurality of threaded fasteners148respectively extending laterally through apertures150(e.g., openings) in corresponding ones of the side walls141of the lower part106of the housing102and into corresponding threaded apertures152disposed in corresponding ones of the side walls138of the upper part104of the housing102, and arranged such that advancement of the fasteners148into the threaded apertures152acts to pull the planar surfaces142of the side walls138of the upper part104into engagement with corresponding ones of the planar surfaces144of the side walls141of the lower part106. In one embodiment, threaded apertures152may be provided by side walls138of the upper part104(e.g., integral therewith). In another embodiment, threaded apertures152may be provided by separate components153(e.g., nuts or bushings) that are pressed, welded, and/or otherwise attached positioned into apertures151of the upper part104(e.g., positioned within lumen112when hand guard100is assembled).

Additionally, in some embodiments, the threaded apertures152in the side walls138of the upper part104can be respectively disposed a first distance above the lower edge140of the corresponding side wall138of the upper part104, and the apertures150in the side walls141of the lower part106can be respectively disposed a second distance above the ledge146of the corresponding side wall141. The first distance can be made slightly greater than the second distance (e.g., greater by a distance of approximately 8 thousandths of an inch in one embodiment), such that advancement of the threaded fasteners148into the threaded apertures152further acts to pull the lower edges140of the side walls138of the upper part104into a tight engagement with the corresponding ledges146of the side walls141of the lower part106, thus ensuring a tight coupling of the upper part104to the lower part106.

In some embodiments, as shown inFIG. 3, apertures150may be implemented with countersinks155. In one embodiment, countersinks155may be offset downward or otherwise (e.g., by approximately 8 thousandths of an inch in one embodiment) such that upper portions of heads149of threaded fasteners148contact rail113and/or the lower part106before threaded fasteners148are fully screwed into threaded apertures152and fully seated within countersinks155. Such contact can provide compressive force to further secure upper part104and lower part106together.

As illustrated in, e.g.,FIGS. 2 and 3, selected ones or all of the side walls of the housing102can include a pattern of vent holes154extending therethrough. The vent holes154serve to reduce the weight of the hand guard substantially, and can also serve both to cool the barrel24of the rifle10during extended firing thereof, thereby ensuring that the hand guard100remains cool to the touch, and also to mount certain types of accessories to the hand guard100(e.g., such as lighting device190in one embodiment). In various embodiments, accessories may be mounted directly to vent holes154(e.g., without requiring rail clamp192or other mounting mechanisms).

FIG. 10is an upper left side perspective view of a receiver and barrel of an M4 rifle10(e.g., with rear sight14removed), showing a second example embodiment of a hand guard200in accordance with the present disclosure mounted thereon, andFIG. 11is an upper, front, right side perspective view of the receiver, barrel and second example hand guard200ofFIG. 10, showing an example accessory mounting bracket201mounted on the right side thereof.

As can be seen from a comparison of the figures respectively illustrating the first and second example hand guards100and200, the two example hand guards100and200differ in various ways such as, for example, the mechanisms used to spread the lower part of the hand guard and expansion collar apart from each other so as load the assembly of the expansion collar and the lower part of the housing of the hand guard in compression between the two radial surfaces34and36of the rifle10, coupling mechanisms and engagement surfaces, features in the side walls of the hand guard housing that enable various accessory mounting brackets to be coupled to it efficiently and reliably, and other features further discussed herein.

FIGS. 12 and 13are upper, front, left side perspective and exploded perspective views of the second example hand guard200, respectively. As illustrated inFIGS. 12 and 13, the second example hand guard200can, like the first example embodiment100above, comprise an elongated tubular housing202having an upper part204, a lower part206, opposite open ends208and210, and a longitudinal lumen212configured to accommodate the gas tube30and intermediate portion32of the barrel24of the rifle10longitudinally therein.

As illustrated in the cross-sectional view of the housing202in FIGS.16and19A-19C, the housing202can have a generally polygonal cross-section, and in the particular embodiment illustrated, the housing202has eight side walls, i.e., has a cross-sectional shape that is octagonal. Of course, other cross-sectional shapes, including round or annular, can also be used. At least one of the side walls of the housing202can comprise an integrally formed, longitudinal accessory mounting rail213, such as specified in MIL-STD-1913 and commonly referred to as a “Picatinny” rail, or as discussed below, a variation thereof. In the particular example embodiment illustrated in FIGS.16and19A-19C, two such integral accessory mounting rails213are provided, i.e., one disposed atop the top wall of the upper part204of the housing202, and one disposed on the bottom wall of the lower part206thereof.

As illustrated inFIGS. 10 and 11, when the second example hand guard200is installed on the receiver12of the rifle10, a top rail213on the upper part204can be disposed substantially level with another rail270(e.g., another longitudinal accessory mounting rail, such as another Picatinny rail or other type of rail). Such positioning of the rails213and270can advantageously enable various accessories to be mounted substantially in line with each other on the rails213and270and/or enable such accessories to be mounted across both rails213and270(e.g., using the mounting locations of both rails213and270). As discussed above in connection with the first example embodiment100, one or more accessories can be mounted on the rails213such as, for example, lighting devices, sighting devices, and/or other types of devices.

In some embodiments, the upper part204can include one or more protrusions282(e.g., one or more flanges or individual protruding members) configured to engage or overlie a front end portion of the receiver12(see, e.g.,FIGS. 10-12). For example, the protrusion282can extend over, rest upon, and/or push against various external portions of the retainer40. In some embodiments, the lower part206can include one or more protrusions280(e.g., implemented as one or more flanges or individual protruding fingers) configured to engage or contact the retainer (e.g., barrel nut)40(see, e.g.,FIGS. 12 and 13). For example, the protrusions280can rest upon and/or push against the retainer40. In various embodiments, the protrusions280and/or the flanged portion282can be used to further secure the hand guard200to the rifle10.

As illustrated in, e.g.,FIGS. 12,13,17A-17E,20A and20B, the second example hand guard200also comprises an expansion collar214disposed at one end of the housing202. The expansion collar214incorporates an expansion mechanism, described in more detail below, that is configured to adjustably compress the expansion collar214and the lower part206of the housing202longitudinally between the radial surfaces34and36located at opposite ends of the intermediate portion32of the barrel24, as described above. In the particular embodiment illustrated in the figures, the expansion collar214is shown disposed adjacent to the front end208of the housing202, but as those of some skill in this art will appreciate, this arrangement can be reversed, such that the expansion collar214is disposed adjacent to the rear end210of the housing202.

Additionally, as illustrated in, e.g., FIGS.13and17A-17E, the expansion collar214can include a pair of longitudinal tongues216that can be slid into a complementary recess in the adjacent open ends208or210of the housing202to generally align the collar214concentrically with the housing202and the lumen212thereof.

As illustrated in, e.g.,FIGS. 13 and 20A, in one embodiment, the expansion mechanism can comprise a pair of longitudinally extending screws218(also referred to herein as jack screws) respectively received in corresponding ones of a pair of threaded apertures217respectively contained in a corresponding pair of laterally opposing stanchions219respectively attached to the inner surfaces of the side walls241of the lower part206. In the particular example embodiment illustrated in the figures, each of the two side wall stanchions219is attached to a corresponding side wall241of the lower part206by a pair of threaded fasteners221that extend through corresponding through-apertures in the adjacent side wall241and into corresponding threaded apertures in the stanchions219. However, as those of some skill will understand, the stanchions219can be coupled or connected to the side walls241of the lower part206using other methods, such as brazing, welding, staking, riveting, adhesive bonding and so on.

As illustrated inFIGS. 17D and 20A, each of the longitudinal tongues216of the expansion collar214includes a longitudinal bore220having an open side and a bottom end surface224. Each jack screw218has a distal end that can be urged into abutment with an corresponding one of the bottom end surfaces224of the longitudinal bores220by advancing the jack screw218in the threaded aperture217of the corresponding stanchion219. Thus, as the screws218are advanced within the threaded apertures217of the stanchions219(e.g., in an opposite direction as screws118of hand guard100), the resulting longitudinal expansion of the hand guard200causes the protrusions280to push against the retainer40and thereby tighten the end210of the hand guard200against the forward facing surface36of the receiver12of the rifle10.

As illustrated in, e.g.,FIGS. 13 and 20B, in some embodiments, the expansion mechanism can further include a plurality of elongated compression members228that extend longitudinally from an end of the expansion collar214opposite to the end of the housing202at which the expansion collar214is disposed. As illustrated inFIG. 20B, the compression members228can include a first end portion230that can comprise a material that can compress and expand (e.g., being at least partially deformable, compressible, and/or expandable) while still remaining relatively resilient, such as a rubber or polyurethane, which is disposed in a corresponding bore232(see, e.g.,FIG. 17B) in the expansion collar214, and an opposite second end234that can comprise a relatively harder bearing material, e.g., a metal, such as steel or aluminum.

In some embodiments, the second example hand guard200can be mounted on an associated rifle10in accordance with the following example mounting method, in which it is assumed that the expansion collar214is mounted at the front end208of the housing202and disposed adjacent to the front radial surface34of the rifle10, as illustrated in the example embodiment ofFIGS. 10 and 11. However, as discussed above, this orientation can be reversed, if desired.

First, the upper part204of the housing202is removed from the lower part206, which can be effected in a manner described in more detail below. The longitudinal tongues216of the expansion collar214are inserted into the front end208of the lower part206of the housing202to form a loose assembly therewith. The assembly of the expansion collar214and lower part206of the housing202is then mounted onto the lower surface of the intermediate portion32of the rifle barrel24and between the radial surfaces34and36disposed at the opposite ends thereof, i.e., with the compression members228of the expansion collar214disposed adjacent to the rear-facing front surface34and the rear end210of the lower part206of the housing202disposed adjacent to the front-facing rear surface36. In one embodiment, the assembly of the expansion collar214and lower part206of the housing202can be positioned around (e.g., without touching) the intermediate portion32of the rifle barrel24and rotated thereabout until the lower part206of the housing202is disposed below the rifle barrel24.

As illustrated inFIGS. 20A and 20B, the screws218are then advanced in their respective threaded apertures217in the stanchions219such that the distal end of each screw218is disposed in abutment with corresponding one of the bottom end surfaces224of the longitudinal bores220in the tongues216of the expansion collar214. As indicated by the arrows236inFIGS. 20A and 20B, further advancement of the screws218causes the lower part206and the expansion collar214to spread apart from each other longitudinally, thereby loading the entire longitudinal assembly comprising the compression members228, the expansion collar214, and the lower part206of the housing202, in compression between the two radial surfaces34and36, thereby firmly coupling the longitudinal assembly firmly to the rifle10.

As those of some skill will appreciate, this compressive force results in a reactive longitudinal tensile force being applied to the barrel24of the rifle10, which, unlike various prior hand guards, does not result in any twisting or local deformations of the rifle barrel24, and therefore, does not adversely affect the accuracy of the rifle10. Any differences in the respective forces exerted by the screws218are taken up by the plurality of compression members228, which compress or expand locally (e.g., effected by the resilient material of first end portion230) to ensure that the force exerted by the screws218is substantially uniformly distributed among the compression members228and on the adjacent end of the bottom part206of the housing202. Although such compression and expansion is described as being effected by the material of the first end portions230of compression members228, such operation can also be provided by any component of the hand guard200. For example, in one embodiment, this function may be effected by, for example, a spring comprising a part of the jack screws218and/or other components adapted to compress and expand between the end208of the lower part206of the housing202and the rear-facing radial surface34.

One of the many advantages provided by the embodiments of the hand guard100and200of the present disclosure is that the upper part104or204of the housing102or202can be removed from the lower part106or206of the housing102or202, e.g., to gain access to the gas tube30and/or the intermediate portion32of the barrel24, without having to remove the lower part106or206and the expansion collar114or214from the rifle10. As illustrated in, e.g.,FIGS. 13 and 16, this can be effected in the case of the second example hand guard200by the provision of a coupling mechanism for releasably coupling the upper part204of the housing202to the lower part206thereof. Moreover, the lower part206can remain tightly engaged with surfaces34and36(e.g., by longitudinal expansion) while the upper part204is removed. As a result, accessories installed on the lower part206can remain attached and in alignment with the rifle10while the upper part204is removed. Also, any accessories installed onto the upper part204can also remain attached and in alignment with the upper part204when the upper part204is removed. Thus, if the upper part204is subsequently re-attached to the lower part206, all accessories attached to the hand guard200, whether mounted on the upper part204or the lower part206will remain aligned and ready for use without requiring further adjustment by the user.

In other embodiments, the locations and/or configurations of the upper part204and/or lower part206can be changed. For example, in one embodiment, the locations of the upper part204and lower part206can be reversed such that upper part204is actually positioned below the lower part206while hand guard200is installed on intermediate portion32of barrel24. In such an embodiment, the upper part204can be lowered downward from rifle10(e.g., lowered down to the trigger side of rifle10) while lower part206remains installed (e.g., positioned on a top side of the rifle10and straddling the intermediate portion32of the barrel24). Indeed, in this embodiment (and applicable to hand guard100and200), it is possible to omit the upper part104/204entirely and install, for example, a grenade launcher or other component in its place below the barrel24of the rifle10. In other embodiments, upper part104/204may be omitted while lower part106/206is positioned on a bottom side of the rifle10(e.g., to permit installation of any desired apparatus in place of upper part104/204above barrel24). In any case, omission of upper part104/204may also permit the user to gain access to barrel24, gas tube30(e.g., in some embodiments, gas tube30may not be accessible while upper part104/204is removed), and/or other portions of rifle10while lower part106/206remains installed in a position on a bottom side or top side of rifle10.

As illustrated in, e.g.,FIGS. 13,15B,15C, and15E, the upper part204of the housing202can include a pair of laterally spaced, downwardly extending lateral side walls238, and inclined side walls239(e.g., inclined approximately 45 degrees relative to side walls238). Each of side walls238include a generally planar exterior surface242and a flange243(e.g., a downwardly projecting engagement surface extending over lateral side walls238). As illustrated in, e.g.,FIGS. 13,14C, and16, the lower part206of the housing202can have a pair of laterally spaced, upwardly extending lateral side walls241, and inclined side walls247(e.g., inclined approximately 45 degrees relative to side walls241). Each of side walls241has a generally planar interior surface244and also an upper edge245(e.g., an upwardly projecting engagement surface at the intersection of angulated faces255A-B). As illustrated in FIGS.16and19A-19C, the side walls238of the upper part204are positionable inside the side walls241of the lower part206such that respective ones of the planar exterior surfaces242of the side walls238of the upper part204are disposed in facing opposition to corresponding ones of the planar interior surfaces244of the side walls241of the lower part206. Moreover, flange243of upper part204may be brought into contact with upper edge245of lower part206.

As illustrated in, e.g.,FIGS. 12 and 13, the coupling mechanism can comprise a plurality of threaded fasteners248respectively extending laterally through apertures250in corresponding ones of the side walls241of the lower part206of the housing202and into corresponding threaded apertures252disposed in corresponding ones of the side walls238of the upper part204of the housing202, and arranged such that advancement of the fasteners248into the threaded apertures252acts to pull the planar surfaces242of the side walls238of the upper part204into engagement with corresponding ones of the planar surfaces244of the side walls241of the lower part206. In one embodiment, the threaded apertures152can be provided in the side walls238of the upper part204(e.g., integral therewith). In another embodiment, the threaded apertures252can be provided by separate components (e.g., nuts or bushings) that are pressed, welded, and/or otherwise attached positioned into corresponding apertures in the upper part204(e.g., positioned within the lumen212when the hand guard200is assembled).

Additionally, in some embodiments, the threaded apertures252in the side walls238of the upper part204can be disposed such that they are slightly higher (e.g., offset by a distance of 8 thousandths of an inch in one embodiment) than the apertures250in the side walls241of the lower part206when upper part204is inserted into lower part206(e.g., when flanges243of upper part204are in contact with upper edges245of lower part206but before upper part204and lower part206have been secured together). As threaded fasteners248are advanced into the threaded apertures252, the offset between apertures250and252causes flanges243of the side walls238of the upper part204to be pulled into a tight engagement with the upper edges245of the side walls241of the lower part206, thus ensuring a tight coupling of the upper part204to the lower part206.

As illustrated inFIG. 13, in some embodiments, the apertures250can be implemented with frustoconical countersinks. In one embodiment, the countersinks can be offset downward or otherwise (e.g., by approximately 8 thousandths of an inch in one embodiment) such that the upper portions of the heads of the threaded fasteners248contact the rail213and/or the lower part206before the threaded fasteners248are fully screwed into the threaded apertures252and fully seated within the corresponding countersinks. Such contact can provide compressive force to further secure the upper part204and the lower part206together.

As illustrated in, e.g.,FIGS. 12 and 13, selected ones or all of the side walls of the housing102can include a pattern of apertures251(e.g., in upper part204) and259(e.g., in lower part206). Apertures251and259reduce the weight of the second example hand guard200substantially, and also permit cooling of the barrel24of the rifle10during extended firing thereof, thereby ensuring that the hand guard200remains cool to the touch.

Additionally, as discussed below, apertures251and259may be used to implement elongated slots254A-B to define rails289which may be used to mount accessories to the hand guard200, e.g., such as, for example, rails262illustrated inFIGS. 10,19A, and19B, the accessory mounting bracket201illustrated inFIG. 11, and/or other accessories. In some embodiments, slots254A may be defined by apertures251in inclined side walls239of upper part204and upper edge245of lower part206. In some embodiments, slots254B may be defined entirely by apertures259in inclined side walls247of lower part206.

FIGS. 19A-19Care cross-sectional views of the second example hand guard200, as seen along the lines of the section16-16taken inFIG. 12, showing various accessory and accessory bracket mounting features. As discussed above and illustrated inFIGS. 19A-19C, at least one of the side walls of the housing202can comprise an integral, longitudinal accessory mounting rail213, such as specified in MIL-STD-1913 and commonly referred to as a “Picatinny” rail. In the particular example embodiment illustrated in the figures, the housing202includes two such integral accessory mounting rails213, viz., one disposed atop the top wall of the upper part204of the housing202, and one disposed on the bottom wall of the lower part206of the housing202. In this regard, each side of rails213include two angulated faces253A-B (seeFIGS. 19A-C) which subtend an angle θ of about 90 degrees, and the width w between the respective intersection of the angulated faces253A-B on either side of each rail213is about 0.835 inches.

Additional side rails289may be provided with “Picatinny rail” features, but having a substantially reduced height relative to conventional Picatinny rails213(e.g., without the “neck” portion256of the conventional Picatinny rail213). In this regard, rails289include angulated faces255A-B and255C-D provided on opposite sides of lateral side walls241and proximate to slots254A-B. Slots254A (e.g., having perimeters defined by apertures251in inclined side walls239of upper part204and upper edge245of lower part206as discussed) define angulated faces255A (e.g., interior facing angulated faces corresponding to portions of upper edge245of lower part206). Slots254B (e.g., having perimeters defined by apertures259in inclined side walls247of lower part206as discussed) define angulated faces255C (e.g., interior facing angulated faces). External surfaces of lateral side walls241may provide angulated faces255B and255D (e.g., exterior facing angulated faces).

Angulated faces255A-B and255C-D of rails289may exhibit the same angle θ and the same width w as described for angulated faces253A-B of rails213. However, as can be seen inFIGS. 19A-C, the respective outer surfaces291of rails289are generally coplanar with the respective outer surfaces of the side walls241of the lower part206. Thus, the “neck” portion256of the conventional Picatinny rail213is eliminated in rails289, resulting in a lighter, narrower, easier-to-grip hand guard200without any sacrifice in accessory mounting capabilities.

FIG. 18Ais an upper, front, left side perspective view of the example accessory mounting bracket201shown inFIG. 11, andFIG. 18Bis an upper, front, right side perspective view thereof. The bracket201can be configured to mount, for example, a light190discussed above in connection withFIG. 3. As illustrated inFIG. 18A, in some embodiments, the mounting bracket201can comprise two pairs of fingers258A and258B configured to engage a Picatinny rail. In some implementations, the pair of fingers258A can be fixed on the bracket201and the other pair of fingers258B can be arranged to pivot toward and away from the fixed pair258A, for example, by turning the head of an actuating member260of the type illustrated inFIG. 18B. As illustrated inFIG. 19C, this arrangement enables the mounting bracket201to be clamped to a side wall (e.g., as fingers258A-B extend through slots254and around side wall241) of the housing202using the “reduced-height” Picatinny rail design discussed above.

If desired, conventional Picatinny accessory mounting rails262can be mounted on the outer surfaces of the side walls of the upper and/or lower parts204and206of the hand guard housing202(e.g., mounted on rails289, using apertures251of upper part204, using apertures259of lower part206, using apertures261in lateral side walls241, and/or others). As illustrated in the figures, these can be mounted to corresponding ones of the side walls using, for example, threaded fasteners264(e.g., seeFIGS. 19B-C), but it should be understood that they can also be mounted to the housing202using other fastening techniques, such as riveting, adhesive bonding and the like.

As shown inFIG. 21, side walls241of lower part206include recesses207. Recesses207may be used to position various types of accessories, such as clamp mounts and/or other devices, on hand guard200. For example,FIG. 21illustrates a lighting device290(e.g., a SureFire Scout Light in one embodiment) attached to a clamp mount292. Clamp mount292is more clearly shown in the assembled view ofFIG. 22and the exploded view ofFIG. 23.

Clamp mount292may include a bolt293, a first clamp member294, a roll pin295, a second clamp member296, a washer297, a split lock washer298, and a nut299. Clamp mount292may be installed on a side wall241using slots254in a similar manner as described with regard to mounting bracket201. For example, rotation of nut299may cause first and second clamp members294and296to be pulled toward each other to cause at least a flange296A of second clamp member296to extend around side wall241.

As shown inFIG. 22, when clamp mount292is assembled, a shank293A of bolt293is exposed. Recesses207in side walls241may be configured (e.g., having substantially scalloped and/or rounded interior surfaces complimentary to shank293A) to receive shank294A while clamp mount292is installed. Such engagement of a recess207with shank294A permits clamp mount292to be conveniently and rapidly positioned at one or more predetermined positions along (e.g., relative to) side wall241. Other configurations of recesses207and clamp mounts292may be used where appropriate.

The foregoing description is presented so as to enable any person skilled in the art to make and use the invention. For purposes of explication, specific nomenclature has been set forth to provide a thorough understanding of the disclosure. However, it should be understood that the descriptions of specific embodiments or applications provided herein are provided only by way of some example embodiments of the invention, and not by way of any limitations thereof. Indeed, various modifications to the embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention should not be limited to the particular embodiments illustrated and described herein, but rather, should be accorded the widest possible scope consistent with the principles and features disclosed herein.