Replacement stock system for rifle

A trigger assembly group of the type used with a rifle stock replacement system is provided. The trigger assembly group and may include a trigger assembly, including a trigger coupled to a trigger rod, a locking plate coupled to the trigger rod and a preload cylinder coupled to the locking plate. This in combination with the firing elements of the existing rifle may comprise a firing control mechanism. The trigger assembly group may also include a trigger block with a recess adapted to receive the trigger rod and the locking plate. A safety spool may be a part of the trigger assembly group and include a cross hole, which may be adapted to receive the preload cylinder when the safety spool is in a first position and not receive the preload cylinder when the safety spool is in a second position.

FIELD OF THE INVENTION

The present invention generally relates to firearm modification packages and, more particularly, replacement stock systems including safety mechanisms for firearms.

BACKGROUND OF THE INVENTION

In the 1940's, after WWII, the US Military desired a replacement rifle for the M-1, the Browning Automatic Rifle, the Carbine and the M3 A-1 Sub-machine gun. In many cases a squad would be carrying each of these four weapons in battle. The variety of weapons and ammunition was inefficient and as such, a replacement weapon for all four of the above mentioned weapons was developed. This weapon was the U.S. Rifle M14.

The M-14 uses a standard 7.62 mm×51 NATO round and may be fired semiautomatic (one round fired with each trigger pull), or full automatic (continuous fire as long as the trigger is held in the firing position and there are rounds in the magazine). The M14 has a muzzle velocity of 800 m/s (2800 ft/sec) and provides a high degree of accuracy along with an effective range rating of 800 meters (with optics). The M14 is still used today as a sniper rifle in some military units. The M14 works well in dirty conditions, providing a reliable platform for putting rounds down range with a firing rate of 700-750 rounds per minute. Numerous variations of the M14 have been made including the M39 Enhanced Marksman Rifle (EMR). This is used by a Designated Marksman when precision fire is needed but does not rate a Scout Sniper. In addition, Marine Scout Snipers and Explosive Ordnance Disposal teams use this platform when rapid and accurate fire is needed.

In the 1960's, during the Vietnam conflict, solders complained of the weight of the M-14 in jungle warfare. An M-14 with a loaded 20 round magazine and no optics weighs 11.5 lbs. New on the scene was the M-16, which uses the smaller 5.56 mm×45 NATO round. A M16A1 with a full 30 round magazine weighed in at a mere 7.9 lbs. The slightly modified M16A2 had a firing rate of 700-950 rounds per minute and a muzzle velocity of 950 m/s (3100 ft/sec), both greater than the M14, but the maximum effective range was lower at 550 meters. The smaller 5.56 mm M16 round not only lacked in the range of the M14, but also lacked stopping power compared to the 7.62 mm round of the M14. The M14 has a 22 inch barrel with an overall length of 44 inches. The M16A2 is 39.5 inches long and all M16 variations use a 20 inch barrel. Other variations of the M16, including the M4 Carbine uses a 14.5 inch barrel with an extended stock length of 33 inches. The shorter barrel reduces the maximum effective range but the shorter rifle makes maneuvering the rifle in a shooting position easier when clearing buildings and going through doorways.

In today's urban warfare environments, it may be desirable to combine the reliable and more powerful platform of the M14, but put it in a lighter and more compact tactical weapon platform. This need may be met by the Bullpup. The Bullpup may take the M14's 22 inch barrel, receiver and trigger group and position it in a stock to provide a more compact weapon than the 44 inch traditional M14 rifle. This may be done by locating the proximal end of the barrel behind the trigger group. To accomplish this, the stock and rail assemblies may be replaced and a new trigger assembly added, which actuates the existing M14 trigger assembly. The existing barrel of the M14 is still used. There have been attempts to create Bullpup rifles, which have been met with limited success. A common area of deficiency of existing systems is the interaction between the new trigger and the existing M14 trigger, several inches away. In addition to the coupling of the actuation of the old trigger with the new trigger, there is a need for a reliable safety to prevent actuation of the weapon when set to “safe”. The firing control mechanism as shown and described may provide these features.

SUMMARY OF THE INVENTION

The present invention provides a trigger assembly group of the type used with a rifle stock replacement system. The trigger assembly group may include a trigger assembly, including a trigger coupled to a trigger rod, a locking plate coupled to the trigger rod and a preload cylinder coupled to the locking plate. The trigger assembly group may also include a trigger block with a recess adapted to receive the trigger rod and the locking plate. A safety spool may be a part of the trigger assembly group and include a cross hole, which may be adapted to receive the preload cylinder when the safety spool is in a first (firing) position and not receive the preload cylinder when the safety spool is in a second (safety) position.

The preload cylinder may include a threaded screw portion and be received in the locking plate, thereby providing the ability to adjust the position of the preload cylinder relative to the locking plate. The trigger assembly group may also include a preload locking screw, which may be received by the locking plate and positioned non-collinear with the preload cylinder, and may be positioned substantially orthogonal to the preload cylinder. The preload locking screw may be adapted to provide a frictional force on the preload cylinder to restrict movement of the preload cylinder relative to the locking plate, thus locking it in place.

The trigger assembly group may also include a front trigger stop received by the trigger block and may be positioned to restrict the movement of the trigger assembly in a direction opposite to the first direction, or restrict movement toward the muzzle end of the firearm. There also may be included a trigger stop locking screw which may be received by the trigger block and may be positioned non-collinear with the front trigger stop. The trigger stop locking screw may be positioned substantially orthogonal to the front trigger stop, whereby the trigger stop locking screw may provide a frictional force on the front trigger stop to restrict movement of the front trigger stop relative to the trigger block, thereby locking the front trigger stop in place.

A safety spool pin may be provided and received by the trigger block. The safety spool pin may be adapted to provide a resistance to movement of the safety spool relative to the trigger block. This may be done by providing a spring biased ball in the safety spool pin. The ball may provide a frictional force on the safety spool commensurate to the contact surface topography of the safety spool, in that the safety spool may include one or more detent holes that receive the ball, thus releasably locking the safety spool in a position relative to the trigger block.

An exemplary method for restricting the action of a trigger on a firearm for use with a firearm is provided, including the components as previously disclosed and including the steps of rotating the safety spool from the first position to the second position and moving the preload cylinder by way of the trigger and trigger rod such that the preload cylinder contacts the safety cylinder, preventing the firearm from firing. This method may also include the steps of adjusting the position of the preload cylinder relative to the locking plate, providing a preload locking screw and securing the preload cylinder in a position relative to the locking plate by positioning the preload locking screw against the preload cylinder.

The firing control mechanism may include a primary safety lever that captures the original trigger safety tab, which may be a part of the original trigger group. This lever may be rotated toward the rear to disable the original trigger group or forward to enable actuation of the original trigger group. Used in combination with the safety spool and trigger rod described herein, the firearm can be made fully safe. Without this element of the firing control mechanism, the rifle may remain capable of unintended discharge, thus creating a potentially significant safety risk.

For purposes of summarizing the invention and the advantages achieved over the prior art, certain advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages can be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following description of the preferred embodiments and drawings, the invention not being limited to any particular preferred embodiment(s) disclosed.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the illustrative drawings, and particularly toFIGS. 1-4, there is shown a rifle assembly16including a replacement stock system in accordance with the present invention. The rifle assembly16may include an upper rail assembly18, a trigger assembly group20and a stock assembly22, including a cheek panel24and a magazine26, though the magazine26is not considered part of the invention and is shown only for illustrative purposes. InFIG. 1, the rifle assembly16is shown in an assembled state.

With reference toFIG. 2, the rifle assembly16, as shown inFIG. 1from a top view with section line 3-3 shows the location of the section, as shown inFIG. 3. The section shown inFIG. 3illustrates the interaction of the some parts of an existing rifle assembly16, such as, some elements of the upper rail assembly18, including the barrel28, and the primary trigger group30which may work with other elements of the rifle assembly16, including the trigger assembly group20, to make a fully functional firearm with a shorter overall length compared to the original rifle.

With reference toFIG. 3, the trigger assembly group20may include a secondary trigger32coupled to a trigger rod34with a trigger roller36on a distal end of the trigger rod34. The trigger roller36may articulate with the primary trigger38of the primary trigger group30. If the secondary trigger32is actuated toward the rear of the rifle assembly16, the trigger rod34and trigger roller36may also move in the same direction to apply a force to the primary trigger38, which may be used to fire the rifle assembly16. This combination allows for space optimization in that a longer barrel28may be used in a rifle assembly16with the shortest possible overall length. As previously noted, this bullpup design may have several advantages in a close quarter combat environment, without sacrificing accuracy provided with longer barrels of a traditional rifle.

With reference toFIG. 4, a partially disassembled rifle assembly16is shown with the subassemblies of the rifle assembly16illustrated in groups. The upper rail assembly18is the only subassembly which includes components from an existing rifle. The stock assembly22, including the cheek panel24and the trigger assembly group20are all new elements of the replacement stock system of the present invention.

The interaction of the “old versus new” of the present invention may be more clearly illustrated inFIGS. 5-7. With the stock assembly22removed, the upper rail assembly18and the trigger assembly group20are clearly shown from a left side inFIG. 5, from a right side inFIG. 6, and an isometric partially disassembled inFIG. 7. In these views, the old parts, namely the barrel assembly group40, may include the barrel28, the Op Rod charging handle42and primary trigger group30, including the primary trigger38. In the case of an automatic or semi automatic gas powered rifle, as is shown here in the barrel assembly group40, a gas cylinder44and operating rod46may also be included in the barrel assembly group40. To fire the rifle assembly16, the secondary trigger32may be used in a manner consistent with the primary trigger38, if the primary trigger38was accessible to a user. In that the primary trigger group30, and therefore the primary trigger38may be obscured and not easily accessible due to the placement of the primary trigger group30near the shoulder of the user in the bullpup design, the secondary trigger32may be located closer to the muzzle48, so that the user's trigger finger may be in a more comfortable position when using the rifle assembly16.

To accomplish this, the secondary trigger may be coupled to the trigger rod34, which may be supported by a trigger block50to assist in guiding the movement of the trigger rod34, such that the trigger roller36on the distal end of the trigger rod34may interact to actuate the primary trigger38of the primary trigger group30. The trigger rod34may include one or more bends to navigate around the structure of the primary trigger group30without interference, which may interfere with the movement of the secondary trigger32. The trigger roller36, may provide a smoother actuation of the primary trigger38in that the primary trigger38may be pivotally coupled to the primary trigger group30, whereas the secondary trigger32may move in a linear fashion relative to the barrel assembly group40. The interaction of the linear movement with a pivotal movement may require an additional degree of freedom added to the trigger assembly group20to compensate for the angular movement of the primary trigger38. This additional degree of freedom may be provided by the trigger roller36being rotatably coupled to the trigger rod34, thus allowing a bearing surface between the trigger roller36and the trigger rod34. This may provide a smoother transfer of force from the secondary trigger32to the primary trigger38. A smooth trigger pull may provide the user with less superfluous motion during the trigger pull, which may result in a more accurate shot.

InFIG. 7an upper cover rail45is shown displaced from the barrel28with the front mount assembly47and rear mount assembly49located there between. It may be important for the upper cover rail45to be precisely located relative to the barrel28in that one of the functions of the upper cover rail45may be to support any sighting mechanism or optics of the rifle assembly16. As such, the consistent alignment of the upper cover rail45to the barrel28may be desirable. This consideration has been solved by the use of the front mount assembly47, which may include a barrel cavity51, which may be mounted directly to the barrel28, near the muzzle48. In a similar manner, the rear mount assembly49may also be mounted directly to the barrel28, only near the primary trigger group30. Both the front mount assembly47and the rear mount assembly49may be precisely manufactured to provide a consistent mounting height surface53relative to the barrel28. The upper cover rail45may then be supported on the front mount assembly47and the rear mount assembly49and fastened thereto by screws55, thereby providing a reasonably accurate parallel surface of the upper cover rail45and the barrel28.

With reference toFIGS. 8-11, the trigger assembly group20is shown in more detail. InFIG. 8an entire trigger assembly group20is shown. The trigger assembly group20may include a pistol grip52, a trigger guard54, along with the trigger assembly56, which may include the secondary trigger32, the trigger rod34and the trigger roller36, as previously noted. The trigger block58may be disposed on one end of the pistol grip52and may provide a recess60to receive the trigger assembly56.

With reference toFIGS. 10aand10b, the trigger block58has a breakout area removed so as to more clearly show some detail of the parts. In addition, the trigger assembly56has been displaced from the trigger block58to more clearly show the detail of an interaction of the trigger assembly56and the safety spool62. The trigger assembly56may also include a locking plate64coupled to the trigger rod34. The locking plate64may support a preload cylinder66, which may take the form of a threaded screw. A portion of the preload cylinder may extend beyond the locking plate64in the direction of the safety spool62. The safety spool62may include a cross hole68, which may be adapted to receive a portion of the preload cylinder66when the trigger assembly56is moved in the direction of the arrow70. This safety spool62may include one or more safety levers72. The safety levers72maybe rigidly mounted to the safety spool62, the safety spool62may be received by a cylindrical cavity73within the trigger block58so as to provide a defined angular rotation of the safety spool62relative to the trigger block58.

In this embodiment of the invention, the safety levers72are in a down position inFIG. 10awhere the cross hole68of the safety school62may be oriented collinear with the preload cylinder66, when the trigger assembly56is received into the trigger block58. InFIG. 10b, the safety levers72are elevated such that the cross hole68of the safety spool62is now substantially orthogonal to the preload cylinder66, when the trigger assembly56is received into the trigger block58. When the cross hole68is not aligned with preload cylinder66, the preload cylinder66will contact the safety spool62, when the trigger assembly56is moved in the direction of the arrow70, thus limiting its relative movement in that direction. This restriction to movement of the trigger assembly56may act as a safety to restrict the movement of the primary trigger38(not shown here) and thus prevent the rifle assembly16from firing when the safety levers72are in the elevated position.

InFIG. 11a cropped view of a partially disassembled trigger assembly group20is shown. In this view, the trigger block58has another breakout on the far side of the trigger block58. The trigger assembly group20may include adjustments, to allow the user to fine tune the feel of the movement of the trigger assembly56to the individual desires of the user. One adjustment is that of the preload cylinder66relative to the locking plate64. With the trigger assembly56received into the recess60of the trigger block58, a first wrench74may be inserted into a first hole76to access the preload cylinder66. In one form of the invention, the preload cylinder66may be a threaded screw, threaded into the locking plate64. The first wrench74may then screw or unscrew the preload cylinder66, thereby altering the distance the preload cylinder66extends beyond one surface of the locking plate64. The farther the preload cylinder66extends beyond the locking plate64, the less travel the secondary trigger32, and the entire trigger assembly56, will travel within the trigger block58when the safety spool62is in the “safety on” position. This is as is shown inFIG. 10b, the safety lever72is in the up or vertical position. After adjusting the position of the preload cylinder66, the preload cylinder66may essentially be locked in place by the preload locking screw78. The preload locking screw78may also take the form of a threaded screw, and be received by the locking plate64. The preload locking screw78may be positioned substantially orthogonal to the preload cylinder66. The preload locking screw78may contact the preload cylinder66both within the locking plate64, thus providing a frictional force to resist movement of the preload cylinder66relative to the locking plate64. The preload locking screw78may be adjusted by the second wrench80through a side access hole82in the trigger block58.

A second adjustment may be provided near the trigger guard54. A front trigger stop83may be provided, and may also take the form of a screw. The front trigger stop83may be received by the trigger block58and threaded in to allow a portion of the front trigger stop83to extend into the trigger block recess60. The front trigger stop83may offer interference as a stop to limit the forward movement of the locking plate64of the trigger assembly56. The distance the front trigger stop83extends through and into the trigger block recess60, may determine the distance the trigger assembly56may move in the forward direction, toward the trigger guard54, and also may be adjusted with the first wrench74. Once the front trigger stop83in set in place, the front trigger stop83may be secured by tightening a trigger stop locking screw85into the trigger block58until it contacts the front trigger stop83. The trigger stop locking screw85may be positioned orthogonal to the front trigger stop83so that any force applied by contacting the trigger stop locking screw85against the front trigger stop83may provide a side load to the front trigger stop83and inhibit its movement.

A third adjustment may be provided by the third wrench84and adjusting the relative position of a safety spool pin86relative to the trigger block58. The safety spool pin86may include a spring biased ball88on one end. The spring biased ball88may be received by one or more detent holes90in the safety spool62. The third wrench84may be used to screw the safety spool pin86further into the trigger block58. When this is done, the spring biased ball88applies a greater force to the safety spool62, and when the spring biased ball88is received into a detent hole90, a greater force must be applied to the safety lever72to rotate the safety spool62from a “safety on” to “safety off” position. This adjustment allows for the user to adjust the tension required to move and hold the safety lever72in each of the “safety on” and “safety off” positions.

The stock assembly22is shown in an assembled state inFIG. 12and partially disassembled inFIG. 13. The general function of the stock assembly22is to support the upper rail assembly18, and provide a comfortable interaction between the rifle assembly16and the user. One such comfort element is the cheek panel24. The cheek panel24may provide a smooth and consistent surface so that the user may place the side of their face against the cheek panel24while the rifle assembly16is firing. Another function of the cheek panel24is to redirect the expired gas from the breach as the bolt moves to the rear at the moment a cartridge is fired and the spent brass is ejected. Without the cheek panel24, high pressure gas may be directed back toward the operator. This may be more problematic when the rifle assembly16is used in either an automatic or semiautomatic firing mode. The cheek panel24may redirect the expired gas from the breach up and away from the operator. The cheek panel24may be enclosed on all sides with the exception of the open bottom section92. In this embodiment of the invention the cheek panel24may include an open bottom section92for enabling access to the removable cartridge magazine26and also the primary safety110.

The stock94may provide a cradle to support the barrel28of the rifle assembly16. When firing, the barrel28may get extremely warm, especially when firing in full automatic. To help prevent burning the hand of the user, the stock94may support the barrel28while providing an air cushion between the outside of the barrel28and the interior portions of the stock94. Slots96may also be provided in the stock94to assist airflow, and therefore the distribution of heat from the barrel28. The stock94may also provide a means for supporting additional accessories. To facilitate this, a bottom rail98and side rails100may be mounted to the stock94. Accessories that may be mounted to the bottom rail98or side rails100may include a bipod, laser sights or illumination (not shown here).

A rifle sling may also be used to help carry the rifle assembly16and to help support the rifle assembly16when firing. The sling (not shown here) may be supported by attachment to a front sling support102, and a rear sling support104. A recoil pad106may be provided on the distal end of the stock94. The recoil pad106may be positioned against the shoulder of the user while firing the rifle assembly16, thus aiding in dampening the impact force against the user due to the recoil of the rifle assembly16when firing. Spare cheek panel screws108may be stored on the stock94near the recoil pad106.

A primary trigger safety110may be pivotally coupled to the stock94. The primary trigger safety110may be incorporated within the firing control mechanism to provide a complete method to disable or enable the firing mechanism. The primary trigger safety110may be used to provide interference to movement of the primary trigger38. The primary trigger safety110may be accessible to the user through the open bottom section92of the cheek panel24and operate as an additional safety. The original rifle safety may not be accessible to the user as the replacement stock may obstruct access to the original rifle safety. The primary trigger safety110may be coupled to the original rifle safety, and may include a safety arm111. The safety arm111of the primary trigger safety110may extend the structure of the original rifle safety to account for the new stock. This may allow the original rifle safety to be actuated by way of the primary trigger safety110. Therefore, if the weapon is dropped or sustains another type of stress, the likelihood of an accidental discharge of the weapon may be greatly reduced by locking the primary trigger38as well as the secondary trigger32as opposed to only the secondary trigger32.

A pair of tie plates112may be used as a structural reinforcement to improve the mechanical strength of the stock94. To provide for precise machining of the detail of the stock94, a large amount of material may be required to be removed from the stock94. The tie plates112may provide a precise and adjustable means of structural reinforcement of the stock94after the machining process. A receiver leveling screw114may be provided to the stock assembly22, and may be positioned near the recoil pad106. The receiver leveling screw114may be used to fine tune the vertical orientation of the barrel assembly group40when received into the stock assembly22. In that the invention may provide a means to retrofit an existing barrel assembly group40into a new stock assembly22, normal manufacturing variances of the barrel assembly group40, possibly being produced according to slightly different specifications and produced in different factories, may provide variations in overall dimensions. To adjust for these variations, the receiver leveling screw114may fine tune the orientation of the barrel assembly group40, and therefore the barrel28to the stock assembly22. The result may be a more accurate and reliable rifle assembly16. The leveling screw114may also be considered a part of the fire control mechanism. Due to variations in manufacturing tolerances and the desire to stabilize the rifle original trigger group assemblies, the leveling screw114may take a critical role in allowing the new parts to properly align with the old parts. That without some form of adjustment, such as the leveling screw114, the assemblies may be either too loose or too tight, thereby affecting the operation of the firing control mechanism.

The foregoing detailed description of the present invention is provided for purposes of illustration, and it is not intended to be exhaustive or to limit the invention to the particular embodiment shown. The embodiments may provide different capabilities and benefits, depending on the configuration used to implement key features of the invention.