LOCK UP SYSTEM FOR A HANDGUARD

[0001] The present invention relates to an improved lock-up system for a handguard of a firearm. In use, the lock-up system provides a strong, near-permanent locking means for joining the handguard to a corresponding upper receiver.

[0002] Firearms, particularly high caliber rifles, are manufactured in various components, such as an upper receiver that includes a barrel nut and its corresponding barrel extension, a barrel (discharge end), a bolt carrier, a lower receiver, a butt stock, a trigger, and a handguard.

[0003] Handguards are popular components of many firearms, particularly AR 15 rifles and military M16s. Handguards extend over the firearm barrel and allow a firearm user to help align the barrel end of the firearm without touching a hot barrel after discharge. Further, handguards generally contain a plurality of external openings in which accessories, like scopes and level devices, can be attached.

[0004] Handguards generally butt up to and are aligned with the upper receiver. It is desirable to have the connection between a handguard and its corresponding upper receiver be as tight and permanent as possible. However, handguards do not always align end to end as desired and lock up with their corresponding upper receiver and there is resulting “play” between the two components. One option is to buy a one-piece upper receiver/handguard, such as disclosed in U.S. Pat. No. 8,234,808 to Lewis. But manufacturers and OEM manufacturers and some end users like to buy separate handguards and assemble the handguard to the upper receiver post-OEM or in the field. The current known locking systems are bulky in size, difficult to assemble, require laborious timing of the assembly to the upper receiver and can be difficult to remove for updating and maintenance of the rifle.

[0005] The present invention is directed to an innovative solution for providing a lock-up device, a lock-up system that combines a handguard with the lock-up device, and a method for near permanently joining a handguard to a corresponding upper receiver via a barrel nut assembly and the lock-up device.

[0006] According to one aspect of the present invention, the lock-up system is directed to a handguard, a barrel nut, and a wedge assembly.

[0007] The handguard has a first end and a second end with a bore therethrough. The bore is configured to receive the barrel nut. The second end also has a lower lip that is adjacent to the bore. The lower lip has an interior surface that is configured to receive the wedge assembly.

[0008] The barrel nut is configured to receive a barrel of a firearm. The barrel nut has a first end and a second end. The second end is configured to receive a portion of an upper receiver. The first end of the barrel nut has an outer surface that is configured to be received within the bore. The outer surface may be cylindrical in shape.

[0009] The wedge assembly includes a top wedge and a bottom wedge. The upper surface of the top wedge has a generally indented surface, which may be concave in shape. The generally indent surface of the top wedge is configured to be biased against the outer surface of the barrel nut. The lower surface of the top wedge is inclined. The bottom wedge has a lower surface configured to be received into and confront the interior portion of the lower lip of the handguard. The upper surface of the bottom wedge is inclined, complementary to the incline of the lower surface of the top wedge.

[0010] According to another aspect of the present invention, the lock-up system is directed to a combined handguard, upper receiver, barrel nut, and wedge assembly. The barrel nut is affixed to a portion of the upper receiver. Both the upper receiver and handguard have outer edges that closely confront each other in use. The upper receiver has a first end and a second end where the first end closely confronts the second end of the handguard with the barrel nut therebetween mostly positioned within the bore of the handguard. The locked-up handguard and upper receiver may look like a unitary member when assembled.

[0011] The lock-up system may include an optional assembly screw and locator pin. The optional assembly screw is configured to be positioned within a slot of the inclined upper surface of the bottom wedge and a slot that is abutted by a key in the lower inclined surface of the top wedge. The screw may be tightened to bring and retain the top and bottom wedges into close contact. The locator pin may be used to guide and retain the relative position of the top wedge relative to the bottom wedge. The locator pin is configured to be received within an aperture within the bottom wedge from the lower surface to the inclined surface.

[0012] Another embodiment includes a wedge assembly having an upper generally indented surface and a lower inclined (angled) surface that is configured to be received within a complementary inclined (angled) interior surface of a lower lip of the handguard. The alternate embodiment wedge assembly may be unitary in construction.

[0013] Optional fastener or fasteners may be used to retain an exterior portion of the handguard relative to the inserted outer surface of the barrel nut.

[0014] The present invention also includes a method of locking-up a handguard relative to a corresponding upper receiver. The method includes providing a handguard configured as discussed above. A barrel nut, such as described above is affixed to an external portion of the upper receiver that has outer edges that conform to outer edges of the second end of the handguard. The wedge assembly, as discussed above, is positioned within the lower lip of the handguard with the respective inclined surfaces of the top and bottom wedge in a closely confronting relationship. The two inclined surfaces slide against each other to provide tension and pressure. The bore and indented upper surface of the top wedge, now combined and inserted within the lower lip of the handguard, forms a hollow that conforms to the outer edge of the barrel nut. The barrel nut is squeezed into the hollow space between the upper surface of the top wedge and within the bore. One or more fasteners may be optionally added to secure the wedge to the handguard and the barrel nut outer surface to the handguard.

[0015] The method of locking-up the handguard relative to the corresponding upper receiver may include the alternate embodiment where the wedge assembly is optionally unitary in nature so that the pressure is maintained when the lower angled surface of the (preferably unitary) wedge assembly is inserted within a handguard that has a lower lip interior surface that has a complementary angled surface to the lower angled surface of the wedge assembly.

[0016] Similar to the system embodiments, the method may include tightening an optional assembly screw, as well as an optional locator pin to provide further tension and to tighten the bottom wedge to the top wedge.

[0017] Another optional feature is a partial aperture within each outer edge of the handguard and upper receiver, respectively. The partial aperture is aligned with the corresponding aperture of the other respective member (handguard or upper receiver). The combined entire aperture may incorporate an alignment pin that aligns the upper receiver and the handguard.

[0018] In this way, the physical connection between the wedge assembly, handguard, and barrel nut is secure and intended to be permanent.

[0019] These and other advantages are discussed and/or illustrated in more detail in the DRAWINGS, the CLAIMS, and the DETAILED DESCRIPTION OF THE INVENTION.

[0034] Referring to FIGS. 1-9, according to one embodiment of the invention, the lock-up system of the present invention consists of a handguard 1, a bottom wedge 2, a locator pin 3, a top wedge 4, an assembly screw 5, and a barrel nut 6. The lock-up system is designed to attach to any milspec upper receiver 8 and barrel extension 7, illustrated in FIG. 1.

[0035] Locator pin 3 is pressed into a hole 101 of bottom wedge 2 such that a diameter 102 of locator pin 3 protrudes from a lower surface 103 of bottom wedge 2, but not into a slot 104. Assembly screw 5 is inserted into a threaded a hole 105 of top wedge 4 such that a diameter 106 of assembly screw 5 engages an elongated diameter 107 of top wedge 4. Top wedge 4 and assembly screw 5 now engage bottom wedge 2 with assembled locator pin 3 such that an inclined (angled) surface 108 of the bottom wedge 2, and a complementary inclined (angled) surface 109 of the top wedge 4 are in direct contact, and a key 110 of top wedge 4 corresponds to and is positioned within slot 104 of bottom wedge 2. Further, assembly screw diameter 106 is captured within a cutout 111 of bottom wedge 2.

[0036] Referring to FIG. 2, the inclined surface of the bottom wedge may be an angle α in the range of 0.5 to 85 degrees, with a preferred range of 1.5 to 4 degrees as measured from an imaginary plane P-P. The top wedge's complementary inclined surface angle β would be in the range of 0.5 to 85 degrees, with a preferred range of 1.5 to 4 degrees as measured from an imaginary plane P₁-P₁. According to one aspect of the present invention, the angle of the inclined lower surface of the top wedge and the angle of the inclined upper surface of the bottom wedge are equal or substantially so that the overall profile of the combined wedge assembly is generally rectangular in shape.

[0037] Referring particularly to FIGS. 4 and 5, the complete wedge assembly (FIGS. 2 and 3) with bottom wedge 2, top wedge 4, locator pin 3 and assembly screw 5 can now be assembled into handguard 1. The assembly aligns by locating diameter 102 of locator pin 3 into an opening 112 of handguard 1. Lower surface 103 of bottom wedge 2 seats into a lower lip (e.g., slot) 113 of handguard 1. A flat front 114 of top wedge 4 is brought into orientation such that it will be in close proximity of a slot front 115 of handguard 1.

[0038] In use, barrel nut 6 will be fastened onto upper receiver 8 by threads 116 of the barrel nut 6 and threads 117 of the upper receiver 8, thereby holding the barrel extension 7 in place along with any firearm barrel received therein. Holding the wedge assembly (FIG. 2) into position, a wrench may be inserted through opening 118 in the handguard 1, thereby adjusting the assembly screw 5. By turning the assembly screw in a clockwise direction, the screw threads 119 are drawn into the threaded hole 105 of the top wedge 4. As this proceeds, the screw head surface 120 contacts the capture surface 121 of the bottom wedge 2 in such a way as to impede movement of said screw, independent of the bottom wedge 2. Since the assembly screw can move no further, being stopped against the capture surface 121 on the bottom wedge 2, further clockwise rotation of the assembly screw 5 results in motion of the top wedge 4 toward the surface 120 of the assembly screw.

[0039] The two wedges are held in constant contact by an assembler, causing the surface 108 of the bottom wedge 2, and the surface 109 of the top wedge 4 to be held in contact. The motion of the top wedge 4 relative to the bottom wedge 2, assembly screw 5 is turned clockwise. As the smallest ends of each wedge move toward each other, a generally indented, preferably concave, surface 122 of the top wedge 4 moves into closer proximity of the lower surface 103 of the bottom wedge 2. In general, this means that the concave surface 122 of the top wedge 4 is receding from the open diameter 123 of the handguard 1. As this loosening of the wedge continues, the top wedge 4 moves in such a way as to bring its forward surface 114 into contact with the interior surface of lower lip 115 of the handguard 1. A small amount of pressure can be created between these two surfaces (surface 114 and interior surface of lower lip 115) by continuing to rotate the assembly screw 5 clockwise a few degrees beyond the point wherein the surfaces 114, 115 are brought into contact causing the wedge to seat itself open and held in position for assembly and confrontation with the barrel nut 6. At this time, an assembler releases hold of the wedge assembly (FIG. 2), as it is now self-retained.

[0040] With the conditions described it is now possible to slide the handguard 1 with wedge assembly (FIG. 2) over the barrel nut 6, which is threaded onto the threaded end of upper receiver 8. The handguard diameter 123, which is fashioned to be slightly larger than the diameter 124 of the barrel nut 6, together with the wedge assembly surface 122, now forms a relative (e.g., cylindrical) hollow that corresponds to the outer surface (e.g, diameter) 124 of the barrel nut 6. The handguard 1, in combination with the wedge assembly (FIG. 2), now slides onto the barrel nut 6 until confronting contact is made between the handguard 1 and the upper receiver 8 along their respective flat surfaces (125, 126 of FIG. 4). Some form of alignment may be made at this time, such as the addition of an alignment pin (not illustrated) extending between aperture 127 and corresponding aperture 128 of the upper receiver 8 and handguard 1, respectively.

[0041] Once confronting contact is made between the upper receiver 8 and the handguard 1, a wrench may be once again inserted through the handguard opening 118 to access assembly screw 5. By rotating the screw counter-clockwise, a relatively small reverse in the motion of the wedges 2, 4 may be achieved when the surface 129 of assembly screw 5 and the capture surface 130 of bottom wedge 2 make contact. Now the assembly screw 5 will not move independent of the bottom wedge 2 as a result of these two surfaces making confrontational contact. The threaded portion of the top wedge 4 will move away from the head of said screw and down the length of the assembly screw's threaded portion 119. The relative motion of the two wedges results in the larger ends of each wedge moving closer to each other. Concave upper surface 122 of top wedge 4 and lower surface 103 of bottom wedge 2 move away from each other. As this happens, the concave surface has already been put into biasing contact with the cylindrical diameter 124 of barrel nut 6 as the concave upper surface 122 of top wedge 4 moves toward the relative center of the diameter 123 of handguard 1. A squeezing force is applied to the outer diameter 124 of the barrel nut 6. This squeezing force between the handguard inner diameter 123 and the concave upper surface 122 of top wedge 4 that is applied to the outer diameter 124 of the barrel nut 6 affixes the handguard to the barrel nut, holding the relationship between the handguard 1 and the upper receiver 8 near permanently.

[0042] Once the attachment is completed further fasteners can be applied if desired. Two threaded holes 131 are applied to the sides of the handguard 1 in such a way as to be related to the diameter 123 near the middle of the features' longitudinal length. Two set screws can be threaded into these holes such that they protrude into the inner diameter 123 of the handguard 1 and intersect the radial cut 132 of the barrel nut 6. The radial cut 132 of barrel nut 6 is angled back toward the upper receiver 8, and as these set screws are tightened into the radial groove 132, they tend to slide down its angle, being forced toward upper receiver 8. The result is that handguard 1 is forced toward the upper receiver 8, and while no further movement of the handguard toward the upper receiver is possible as the two flat surfaces 125, 126 of handguard 1 and upper receiver 8, respectively, are already in confronting contact with each other, this additional force has the added benefit of resisting any possible movement of the handguard 1 off of the barrel nut 6.

[0043] There are many possible methods of employing wedge surfaces to achieve handguard lock-up of a handguard to a receiver. Above described is a serviceable design and method to achieve this end, but many variations of the wedge surface, its angle, shape, location, and interrelationship to the handguard, barrel nut, and receiver can be created.

[0044] Many possible permutations of the invention exist. One such permutation is an alternate embodiment illustrated in FIGS. 10-13.

[0045] In this embodiment, handguard 11, which is substantially the same as handguard 1, is brought into contact with barrel nut 12 along cylindrical surface 201 of barrel nut 12 and 202 of handguard 11. Handguard 11 has a first end and a second end with a bore 202 therebetween. Similar to the first embodiment, handguard 11 has a lower lip 17 with an interior surface 209 that is configured to receive a wedge assembly 16 via end 206 of wedge assembly 16.

[0046] Barrel nut 12 is substantially the same as barrel nut 6 in the first embodiment, having a first end and a second end where the first end is configured to receive a portion of an upper receiver (not illustrated in FIGS. 10-13) and a second end having an outer surface (e.g., a cylindrical surface) 201 that is configured to be received axially within the bore of the handguard and directly above the lower lip. The interior surface of the lower lip has an inclined surface or surfaces 205 that is complementary to the lower surface(s) 204 of wedge assembly 16.

[0047] The wedge assembly 16 in this embodiment is different in that it does not need an assembly screw, a key/slot combination, or a locator pin. Rather, the wedge assembly has an upper generally indented (e.g., concave) surface 203 and an inclined lower surface 204 that is complementary to the inclined surface 205 of handguard 11. The angles of the inclined surfaces 205 (handguard) and wedge lower surface 204 may be in the same general angled ranges as those discussed in the first embodiment.

[0048] Concave surface 203 is placed in near contact with cylindrical surface 201 of barrel nut 12, and inclined surface or surfaces 204 of wedge assembly 16 are simultaneously brought into contact with inclined surface or surfaces 205 of handguard 11 lower lip 17. In this case, end surface 206 of wedge assembly 16 would begin in its loosened condition in near or exact contact with abutting surface 207 of handguard 11. As assembly proceeds, opposite end surface 208 of wedge assembly 16 would move rearward toward leading edge surface 209 of handguard 11. As this action continues, wedge assembly 16 slides across the contact between its inclined surfaces 204 and the inclined surfaces 205 of handguard 11, causing generally indented (e.g., concave) surface 203 to approach, contact and then pressure the outer (e.g., cylindrical) surface 201 of barrel nut 12. This pressure exerted effectively causes lock-up of the handguard, wedge and barrel nut.

[0049] The present invention may include other variants such as a tapered pin and conical slot as an alternate to the first embodiment. In such a variant, the slot would exist in both the barrel nut and handguard, to which the tapered pin could be applied to bring about said wedge pressure to cause handguard to receiver lock-up.

[0050] These few examples and embodiments, which are by no means exhaustive, are merely intended to illustrate some of the many variations that can occur without departing from the spirit of the invention.