Patent Application
20050011346
The present invention relates to a gun bolt locking mechanism. More particularly, the present invention relates to a device and method for locking a bolt to a bolt carrier during certain stages of the cycle of operation of a self-loading gun. It finds particular utility in a fully automatic gun and especially in a rotary, multi-barreled, machine gun.
The operation of self-loading, single-barreled guns is well known. Whether in semi-automatic or full automatic operation, the rate of fire is limited by the speed at which the gun can load, fire, and eject the spent cartridge of the ammunition being fired. Most of such weapons use the energy associated with the expanding gas or resulting recoil to operate the gun. Rotary machine guns are weapons that are designed to fire ammunition at an extremely high rate when compared to other types of weapons. A rotary machine gun includes a series of barrels that are mounted on a rotor assembly. The rotor assembly is externally driven, that is, power is applied to the rotor to rotate it with respect to a stationary gun housing to load, fire, and eject the spent casing as ammunition is fired in each barrel in rapid succession. As ammunition is fired in one barrel, a round is being loaded into another barrel, while a spent casing is extracted from yet another barrel. In this manner, the rotary machine gun achieves the high rate of fire.
Each round of ammunition is fired by igniting a primer contained within the cartridge case. There are two commonly used methods of igniting the primer. Some guns use electrical energy to ignite the primer, while other guns use mechanical force applied to the primer, normally by a firing pin. Accordingly, there are also two types of ammunition: electrically primed and percussion primed. Electrically primed ammunition must be fired with electrical energy and percussion primed ammunition must be fired with a mechanical impact.
Certain rotary machine guns manufactured by General Dynamics Armament and Technical Products are commonly used as part of the weapons systems on fighter aircraft. It has been discovered that under certain conditions, radiation generated by radar and communications equipment can ignite electrically primed ammunition. When these conditions occur, the uncontrolled ignition of the 20-mm shells creates a serious safety hazard. To eliminate this safety hazard, the aircraft should be able to switch from electrically-primed ammunition to percussion-primed ammunition with little or no modification to the gun.
In certain rotary machine guns having a reciprocating bolt associated with a reciprocating bolt carrier, a means is required to lock the gun bolt in an extended position relative to the bolt carrier during most of the gun cycle (cartridge extract, eject, rear dwell, cartridge feed, and cartridge ram), and to release the extended bolt during the rest of the gun cycle (bolt locking, firing, and unlocking).
With a rotary machine gun that only fires electrically-primed ammunition, the bolt locking mechanism can pass directly through the bolt body. For a firing mechanism that will work with both electric- and percussion-primed ammunition, however, the bolt locking mechanism cannot pass through the bolt body due to the need for a centrally-located firing pin and its spring mechanism.
The present invention is directed to a device and method for locking a bolt to a bolt carrier. While not limited to rotary, multiple-barreled machine guns, the preferred embodiment allows such a gun to fire both electric- or percussion-primed ammunition.
In accordance with one aspect, the present invention is directed to a carrier assembly for a gun. The assembly comprises a gun bolt carrier disposed to reciprocate axially with respect to the central axis of the gun, and a gun bolt disposed to reciprocate axially and rotate within the carrier. The gun bolt has a locking groove therein. The assembly also comprises a bolt locking mechanism extending through a portion of the bolt carrier to selectively engage the locking groove and thereby prevent the bolt from moving with respect to the carrier. The assembly further comprises a generally axial groove in a non-reciprocating portion of the gun that engages and selectively rotates the rotatable bolt locking mechanism to selectively lock the bolt to the carrier.
In accordance with another aspect, the present invention is directed to a multi-barreled machine gun having an externally powered rotor including a carrier assembly that reciprocates along the longitudinal axis of the rotor. The carrier assembly includes a bolt carrier having a gun bolt reciprocally mounted therein. The gun bolt includes a locking groove. The carrier assembly also includes a bolt locking mechanism for selectively locking the bolt to the carrier such that the machine gun is capable of firing both electric and percussion primed ammunition. The bolt locking mechanism comprises a selectively rotatable locking member extending through a portion of the bolt carrier to selectively engage the locking groove and thereby prevent the bolt from reciprocating axially within the carrier. The carrier assembly includes an axial groove in a non-reciprocating portion of the gun that engages and selectively rotates the selectively rotatable locking member to selectively lock the bolt to the carrier.
In accordance with another aspect, the present invention is directed to a method for selectively locking a gun bolt to a bolt carrier in a self-loading gun, including providing a gun bolt locking mechanism in the bolt carrier. The locking mechanism has a crank and crank pin at one end thereof. The crank pin engages a groove in a stationary portion of a gun. The groove is disposed to rotate the locking mechanism when the bolt carrier moves axially within the gun. The locking mechanism includes a bolt locking portion for engaging the bolt. The method also includes timing the rotation of the locking mechanism so that the bolt is locked to the bolt carrier during specific portions of the movement of the bolt.
In yet another aspect, the present invention is directed to the method recited above for a multi-barreled machine gun.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the present invention and together with the description, serve to explain the principles of the invention.
Reference will now be made in detail to embodiments of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
In accordance with the invention there is provided a carrier assembly for a gun. The carrier assembly comprises a gun bolt carrier disposed to reciprocate axially with respect to the central axis of the gun, and a gun bolt disposed to reciprocate axially within the carrier.
As here embodied, and depicted in
As here embodied, and shown in
In accordance with the invention, the bolt in the carrier assembly includes a locking groove therein. As here embodied, and most clearly depicted in
In accordance with the invention the carrier assembly further includes a bolt locking mechanism extending through a portion of the bolt carrier to selectively engage the locking groove and thereby prevent the bolt from reciprocating axially within the carrier. Preferably, the bolt locking mechanism comprises an elongated shaft having a bolt passage groove therein, the bolt passage groove having a shape that allows the bolt to pass through the bolt passage groove.
As here embodied, and shown in
In accordance with the invention, the carrier assembly further includes a generally axial groove in a non-reciprocating portion of the gun that engages and selectively rotates the bolt locking mechanism to selectively lock the bolt to the carrier. By “generally axial” it is meant that the groove has its longitudinal axis generally aligned with the direction of linear movement of the carrier within the gun, but as will be disclosed in detail below, at least a portion of the groove is displaced with respect to the linear motion of the carrier to rotate the bolt locking mechanism.
As here embodied, and disclosed above, the locking shaft 50 further includes a crank 56 and a crank pin 58. The crank pin 58 is offset from the axis of rotation of the locking shaft 50 such that movement of the crank pin 58 in a direction at an angle to the direction of the linear (reciprocating) motion of the carrier will rotate the locking shaft 50.
The bolt 10 is locked in its extended position during the bolt cartridge extract, eject, rear dwell, cartridge feed, and cartridge ram stages of the gun cycle. It is only when the bolt locking mechanism 50 is rotated to release the bolt 10 that the bolt 10 can translate relative to the carrier 1 to its retracted position. The bolt 10 is released by the bolt locking mechanism 50 during the bolt locking, firing, and unlocking stages of the gun cycle.
Preferably, the bolt locking mechanism of the present invention includes a locking portion that engages the bolt carrier to prevent axial movement of the bolt locking mechanism. “Axial movement” of the bolt locking mechanism, means in a direction parallel to the length of the shaft body 52. As here embodied, and depicted in
An exemplary embodiment of a carrier assembly is illustrated in the exploded view of
The non-cylindrical portion of the gun bolt 10 preferably includes a bolt head 12 with locking lugs 14 and a flange extractor 16 for spent shell removal. The gun bolt 10 further includes a camming groove 18 for the cam shaft 20, and a forward aperture 24 for the cocking pin 26. A rear aperture 30 in the gun bolt 10 allows the insulator/bolt assembly pin 32 to slide therethrough. The bolt 10 also includes apertures 33 on opposing sides of a rear end of the bolt that accommodate flanges 42 of a tubular electrical insulator 40.
The insulator 40 preferably includes a forward aperture 44 for the cocking pin 26 and a rear aperture 46 for the insulator/bolt assembly pin 32. The insulator 40 also includes flanges 42, and houses a firing pin 60, a detent pin 70, and a coil spring 80. The detent pin 70 has a forward pin 72 that interacts with the cocking pin 26 and a rear spring guide 74 that interacts with the firing pin spring 80.
Insulator/bolt assembly pin 32 is preferably a cylindrical shaft and may include identical grooves 34 an 36 on ends and a recess 38 along its length for receiving the end of the firing pin spring 80.
The cocking pin 26 includes a detent 27 into which the forward pin 72 can be inserted. The cocking pin insulator 28 includes a rectangular slot 29 within which the cocking pin 26 can slide from its cocked position to its fired position.
The firing pin 60 preferably includes an aperture 64 at the rear, into which the cocking pin 26 is inserted. The cocking pin 26 is retained in the aperture 64 by the front pin 72 of detent pin 70, that passes through the opening 61 in the rear of the firing pin 60 into the opening 27 of the cocking pin 26. At the front of the firing pin 60 is a firing tip 66 for detonating a percussion primer. As disclosed above, the preferred embodiment is also capable of firing electrically primed ammunition. The firing pin is electrically isolated from the carrier assembly by the tubular insulator 40, the insulator pin 32, the insulator 28, and a firing pin insulator 68 surrounding the tip 66 of the firing pin. As here embodied, and depicted in
In addition to providing electrical insulation to the firing pin 60, the firing pin insulator can be made of an electrically insulating material, such as a polymer. The resilience of such a material on the surface of the firing pin reduces or prevents damage to the firing pin and firing pin recess in the bolt face caused by “dry firing” the gun. Moreover, the life of the firing pin and bolt face are extended by the ready and periodic replacement of such a firing pin insulator.
One method of assembling the components of the preferred embodiment includes placing the firing pin 60 into the rear opening of the tubular insulator 40, and then the tubular insulator 40 is inserted into the bolt 10. Lugs 42, on opposing sides of the insulator 40 are inserted into apertures 33 on opposing sides of the bolt 10, and the insulator is turned within the bolt so that the flanges 42 of the insulator 40 engage grooves (not shown) on the inner bolt wall to lock the insulator 40 within the bolt 10. The insulator 40 is locked in the bolt 10 such that the forward apertures 24 and 44, and rear apertures 30 and 46, are substantially aligned. The insulator 28 is placed in the aperture 5.
The bolt 10 is inserted into the bolt carrier 1 through bore 2, so that the apertures 29, 24, and 44, the bore 3 and camming slot 18, and the rear apertures, 4, 30, and 46, are substantially aligned. The cocking pin 26 is inserted through the apertures 29, 24, 44, and 64 of the insulator, the bolt, the tubular insulator, and firing pin respectively.
Next, the detent pin 70 is inserted into the rear opening of the tubular insulator 40, now housed within the bolt 10 and the carrier 1, so that the forward pin 72 is inserted through the opening 61 in the back of the firing pin into the detent 27 in the cocking pin 26. The coil spring 80 is then inserted into the rear opening of the tubular insulator 40 so that the rear spring guide 74 extends into the firing pin spring 80. Next, the spring 80 is compressed and the insulator/bolt assembly pin 32 is inserted in the rear apertures 4, 30, 46, of the carrier, the bolt, and the tubular insulator, respectively, and rotated such that the firing pin spring 80 is seated in the recess 38 of the pin 32.
The cam shaft 20, surrounded by the cam roller 22 is inserted into the carrier bore 3 and camming groove 18, of the carrier and bolt, respectively. Preferably, the cam shaft 20 and the cam roller 22 are secured to the carrier 1 using a removable pin that simplifies assembly.
As can best be seen in
A rotary machine gun typically includes multiple carrier assemblies that reciprocate along tracks in a non-reciprocating rotor. As can be seen in
Firing in a particular carrier 1 occurs after the bolt head 12 rotates after insertion into the firing chamber 100 such that the locking lugs 14 of the bolt head 12 engage locking lugs 102 of the firing chamber 100 (see
As the carrier assembly is guided along the track 90, the crank pin 58 extending from the bottom of the bolt locking mechanism 50 is guided toward the firing position by a generally axial groove that is illustrated as a cam groove 110. Once the crank pin 58 of the bolt locking mechanism 50 reaches a laterally displaced portion of the cam groove 112 (see
Once the bolt 10 can translate relative to the carrier 1 and the breech bolt contacts the aft face of the barrel chamber, the cam shaft 20, which is guiding the carrier assembly, is driven forward through the camming groove 18 in the bolt 10, bringing the carrier 1 forward along the bolt 10. When the carrier 1 slides forward along the bolt 10, it pulls the insulator/bolt assembly pin 32 forward through groove 30 in the bolt 10. Due to the curvature of the bolt grooves 18 and 30, as the cam shaft 20 and insulator/bolt assembly pin 32 move forward through their respective grooves, the bolt 10 is forced to rotate relative to the carrier 1. Due to proper placement of the displaced portion 112 of the groove 110, this rotation occurs after the bolt face 12 has been inserted into the chamber 100, and serves to rotate the bolt 10 so that the locking lugs 14 of the bolt face 12 engage the locking lugs 102 of the chamber 100 (see
Once the bolt face 12 has been locked in the chamber 100, the cocking pin 26 is released from its cocked position. Because the firing pin 60 is biased in a forward direction by the coil spring 80, it immediately slides forward in the rectangular slot 29 of the insulator 28 to its firing position (see
After the cartridge is fired, the carrier assembly is retracted toward its rear dwell position, ejecting the spent cartridge. The cam path for the cam shaft 20 and roller 22 guides them backward such that the cam shaft 20 and therefore the insulator/bolt assembly pin 32 slide through their respective grooves 18, 30, in the bolt 10 until the bolt 10 is in an extended position relative to the carrier 1. The shape of bolt grooves 18 and 30 causes the bolt head 12 to rotate so that locking lugs 14 of the bolt face 12 disengage the locking lugs 102 of the chamber 100. As the carriage assembly slides back along the track, crank pin 58 of the bolt locking mechanism 50 is guided by the cam groove 110 such that when the crank pin 58 of the bolt locking mechanism 50 slides through the groove 110 of the cam groove, it rotates the bolt locking mechanism 50, and particularly its shaft 52, to lock the bolt in its extended position within the carrier 1 before the bolt has completely retracted from the barrel.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. For example, the present invention also contemplates other methods for guiding the bolt locking mechanism such as, for example, a rib that extends from the rotor along which the bolt locking mechanism slides. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
