Patent Grant
6901866
The present invention is related to ammunition rounds, and more particularly to cased telescoped ammunition rounds and ammunition firing systems.
Conventional cased telescoped ammunition is well known, particularly in connection with larger caliber firing systems. Representative conventional cased telescoped ammunition is disclosed in U.S. Pat. No. 4,907,510 (Martwick et al.), U.S. Pat. No. 4,604,954 (Clarke et al.), U.S. Pat. No. 4,335,657 (Bains), U.S. Pat. No. 4,220,089 (Smith); U.S. Pat. No. 4,197,801 (LaFever et al.), U.S. Pat. No. 2,996,988 (Kunz), and U.S. Pat. No. 2,866,412 (Meyer et al.). The cased telescoped ammunition disclosed in these references have drawbacks, and there is a need for a cased telescoped ammunition round assembly that provides improved performance and reliability.
The present invention provides an apparatus and method relating to a cased telescoped ammunition assembly that overcomes drawbacks experienced in the prior art. Under one aspect of the invention, a cased telescoped ammunition assembly is configured to be fired from a firing device. The assembly includes a combustible case body and noncombustible end caps connected to opposing ends of the case body. The case body is configured to be substantially consumed in combustion when the ammunition assembly is fired. An internal support structure is positioned in the interior portion of the case body and connected to the end caps. The internal support structure and the end caps define a load-bearing unit that provides a load path substantially independent of the case body. The load-bearing unit is configured to react external loads, such that the combustible case body is substantially isolated from and does not react the external loads.
Under another aspect of the invention, a method is provided for firing a cased telescoped ammunition assembly. The method includes loading the cased telescoped ammunition assembly into a breech of the firing device, whereby the ammunition round may be exposed to external loads. The external loads are reacted by the load-bearing unit along the load path, such that the case body is substantially isolated from the external loads. Propellant in the ammunition assembly is ignited, whereby the propellant and the case body are consumed in combustion, and the projectile is propelled into the barrel of the firing device. The end caps and the internal support are noncombustible and define a single spent unit after the propellant and the case body are consumed, and the spent unit is ejected from the breech after the projectile has been propelled into the barrel.
A combustible cased telescoped ammunition assembly and a corresponding method for firing the ammunition assembly in accordance with one or more embodiments of the present invention are described in detail herein. The following description sets forth numerous specific details, such as specific materials usable for the assembly and specific structures for use in manufacturing the assembly, to provide a thorough and enabling description for embodiments of the invention. One skilled in the relevant art, however, will recognize that the invention can be practiced without one or more of the specific details. In other instances, well-known structures or operations are not shown, or are not described in detail to avoid obscuring aspects of the invention.
In the illustrated embodiment, the combustible case body 12 is a substantially cylindrical body having an outer diameter slightly smaller than the inner diameter of the breech of the firing device. The case body 12 is fabricated from a combustible composite material, such as a resinated molded fiber composite with an energetic component in the form of nitrocellulose fibers. Alternate embodiments can use other combustible composite materials. The combustible case body 12 is comprised of a forward part 22 and an aft part 24 that mate to form the completed combustible case body 12. The two-piece case body 12 allows for easier manufacture of the ammunition assembly 10. Alternate embodiments, however, can use a single-piece case body 12.
As best seen in
The top and bottom end caps 14 and 16 each have an elastomeric sealing ring 32 attached to the open mouth portion 30 and that extends over the top and bottom end portions 26 and 28 of the case body 12. The sealing rings 32 have an outer diameter approximately the same size as the main portion of the case body 12 and the top and bottom end caps 14 and 16, such that the ammunition assembly 10 has a fairly uniform outer diameter along its length. The sealing rings 32, however, are adapted to expand radially outwardly and seal against the forward and aft ends of the breech when the ammunition assembly 10 is fired. The sealing rings 32 are made of an elastomer that can withstand the temperatures and pressures that occur in the firing chamber upon firing the ammunition assembly 10. After the ammunition assembly 10 has been fired, the sealing rings 32 contract and return substantially to their original pre-fired diameter, so the spent unit can be ejected from the breech of the firing device.
The ammunition assembly 10 includes a propellant bed 34 (shown only partially) contained in the case body 12. The bottom end cap 16 forms the closed bottom end of the ammunition assembly 10 so as to contain the propellant bed 34. The bottom end cap 16 is a noncombustible member than can withstand the high temperatures and pressures generated upon firing without being consumed. In the illustrated embodiment, the bottom end cap 16 is a steel alloy, although other materials can be used. The bottom end cap 16 removably retains an ignition device 36 (e.g., a primer) that extends into the propellant bed 34 to initiate burning and combustion of the propellant bed 34. The burning propellant bed 34 generates high pressure gas within the ammunition assembly 10 and the firing chamber of the firing device, thereby propelling the projectile into and through the barrel of the firing device. When the projectile 20 is fired, the outer end face 42 of the bottom end cap 16 seals against the breech face when the ammunition assembly 10 is in the firing chamber to help contain the high pressure gas in the firing chamber.
On the opposite end of the ammunition assembly 10, the top end cap 14 has an enlarged aperture 38 with substantially the same diameter as a leading portion 40 of the projectile 20 to allow for passage of the projectile through the top end cap upon firing. The outer end face 44 of the top end cap 14 is configured to sealably mate with the barrel face of the firing device when the ammunition assembly 10 is in the firing chamber and fired, thereby properly containing and directing the propellant gases through the top end cap into the barrel during the act of firing. The top end cap 14 is also a noncombustible member similar to the bottom end cap 16 that can withstand the temperatures and pressures generated upon firing without being consumed.
The top and bottom end caps 14 and 16 are securely interconnected to each other by the noncombustible internal support structure 18 positioned within the interior area 19 of the case body 12. The case body 12 extends around the support structure 18 but is not rigidly attached to the support structure. The case body 12 is also not rigidly attached to the top and bottom end caps 14 and 16. In the illustrated embodiment, the case body 12 is sized so it can move a slight distance axially relative to the top and bottom end caps 14 and 16 and the support structure 18 if an external axial load is exerted directly on the case body 12. Accordingly, the case body 12 essentially “floats” on the support structure 18 between the top and bottom end caps 14 and 16.
The top and bottom end caps 14 and 16 along with the support structure 18 define a load-bearing unit that provides a load path through the ammunition assembly 10. The load-bearing unit reacts external tensile, compression or bending loads that may be exerted on the ammunition assembly during handling and loading. The load-bearing unit is also configured to have ductile compressive and tensile properties suitable to withstand the pre-firing loads on the ammunition assembly 10, and also to withstand the forces generated within the firing chamber when the ammunition assembly is fired. The load-bearing unit is substantially independent of the case body 12, so the case body is substantially isolated from the load path and does not react the external loads. Accordingly, the case body 12 can be made of a combustible material that may not be strong enough to react the external loads without being damaged.
The support structure 18 also forms an internal frame-like structure that provides lateral support to the combustible case body 12 so as to help the case body react direct lateral impact loads that may occur during pre-firing handling of the ammunition assembly 10. The support structure 18 also helps maintain the ammunition assembly's overall cartridge cylindrical runout, also known in the industry as cylindricity, which is very important when trying to insert the ammunition assembly 10 into a firing chamber without binding interference.
In the illustrated embodiment, the support structure 18 includes a cylindrical guide sleeve 50 rigidly affixed to the top end cap 14. In one embodiment, the guide sleeve 50 has external threads that threadably mate with internal threads formed in the top end cap 14. The guide sleeve 50 is axially aligned with the top end cap 14 and has an inner diameter substantially identical to the aperture 38 in the top end cap. The guide sleeve 50 snugly yet removably retains the projectile 20 in the interior area 19 and in axial alignment with the case body 12 and the top end cap 14. The guide sleeve 50 is configured to assist in guiding the projectile 20 into the barrel of the firing device upon firing. In the illustrated embodiment, the guide sleeve 50 is made of a high-strength, noncombustible material, such as a steel alloy or the like, that is able to withstand the high temperatures and pressures created upon firing of the ammunition assembly 10.
The support structure 18 of the illustrated embodiment also has a plurality of elongated support rods 52 securely connected to the guide sleeve 50 and to the bottom end cap 16. The support structure 18 shown in
The flame front from the burning propellant ignites the case body 12 and begins consuming the case body in combustion. As the propellant and case body 12 continue to burn, the pressure in the firing chamber 74 greatly increases, thereby creating tension stress on the support structure 18. This tension stress causes the support structure 18 to elastically deform axially within the firing chamber 74. The majority of this elastic deformation is substantially isolated to the middle portion 53 of the support rods 52 because of the reduced diameter of the middle portions. The top and bottom end caps 14 and 16 also move axially and engage the barrel face 78 and the breech face 76, respectively, thereby forming gas seals that prevent propellant gas leakage. The propellant bed 34 and the case body 12 are completely consumed within the firing chamber 74 and the pressures in the firing chamber drive the projectile 20 into the barrel 82 of the firing device 70. In one embodiment, the projectile 20 is adapted to engage rifling grooves (not shown) in the barrel 82 to impart spin to the projectile, and in other embodiments the projectile is adapted for firing through a smooth-bore barrel.
After the projectile 20 is fired out of the barrel 82 and the pressure in the firing chamber 74 and breech 72 is dissipated, the support structure 18 contracts axially substantially to its pre-fired condition, thereby pulling the top and bottom end caps 14 and 16 out of engagement with the barrel face 78 and the breech face 76, respectively. After firing, only the top and bottom end caps 14 and 16, the support structure 18, and ancillary items, such as the ignition device 36, remaining in the firing chamber 74 are retracted into the breech 72 as a unitary spent unit. The spent unit is then ejected from the firing device 70 in an ejection cycle. The support structure 18 holds the top and bottom end caps 14 and 16 in axial alignment during the ejection cycle, thereby greatly minimizing the risk of a jam in the firing chamber 74 or the breech 72, which would take the weapon out of service at least until the jam was cleared.
In one embodiment, the ammunition assembly 10 is usable in a gun or other firing device 70 having a firing chamber 74 configured to move out of alignment with the barrel face 78 and the breech face 76 in order to eject the unitary spent unit and load a fresh ammunition assembly 10. The fresh ammunition assembly 10 is loaded into the firing chamber 74 by pushing it in from the rear of the now open firing chamber. The fresh ammunition assembly 10 is firmly and aggressively pushed against the unitary spent unit, thereby ejecting it out of the front of the firing chamber 74. This reloading process typically creates a substantial axial impact and compressive load on the fresh ammunition assembly 10, and this axial impact is reacted along the load path so the combustible case body 12 is not damaged during the loading process. Upon completion of this loading/ejection cycle, the firing chamber 74 is realigned with the barrel face 78 and the breech face 76, and the chambered fresh ammunition assembly 10 is ready for firing.
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for the purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.
This non-provisional patent application claims priority to provisional U.S. patent application Ser. No. 60/333,577, entitled COMBUSTIBLE CASED TELESCOPED AMMUNITION ROUND ASSEMBLY, filed Nov. 27, 2001, hereby incorporated in its entirety by reference thereto.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2072671 | Foulke | Mar 1937 | A |
| 2866412 | Meyer et al. | Dec 1958 | A |
| 2996988 | Kunz | Aug 1961 | A |
| 3705549 | Quinlan et al. | Dec 1972 | A |
| 3901153 | Brabets et al. | Aug 1975 | A |
| 4015527 | Evans | Apr 1977 | A |
| 4197801 | LaFever et al. | Apr 1980 | A |
| 4220089 | Smith | Sep 1980 | A |
| 4335657 | Bains | Jun 1982 | A |
| 4444115 | Romer et al. | Apr 1984 | A |
| 4535697 | Moser et al. | Aug 1985 | A |
| 4593622 | Fibranz | Jun 1986 | A |
| 4604954 | Clarke et al. | Aug 1986 | A |
| 4763577 | Romer et al. | Aug 1988 | A |
| 4802415 | Clarke et al. | Feb 1989 | A |
| 4815390 | Garcia | Mar 1989 | A |
| 4907510 | Martwick et al. | Mar 1990 | A |
| 5029530 | Martwick et al. | Jul 1991 | A |
| 5042388 | Warren et al. | Aug 1991 | A |
| 5155295 | Campoli | Oct 1992 | A |
| 5160804 | Wähner et al. | Nov 1992 | A |
| 5233928 | Ducros et al. | Aug 1993 | A |
| 5265540 | Ducros et al. | Nov 1993 | A |
| 5333551 | Heitmann et al. | Aug 1994 | A |
| 5388522 | Martwick et al. | Feb 1995 | A |
| 5415104 | Bispling et al. | May 1995 | A |
| 5433148 | Barratault et al. | Jul 1995 | A |
| 5467716 | Boual | Nov 1995 | A |
| 5557059 | Warren et al. | Sep 1996 | A |
| 5841062 | Manole et al. | Nov 1998 | A |
| 6119600 | Burri | Sep 2000 | A |
| 6158348 | Campoli | Dec 2000 | A |
| 6457603 | Freist et al. | Oct 2002 | B1 |
| Number | Date | Country |
|---|---|---|
| 0 483 787 | May 1992 | EP |
| 0 307 307 | Jul 1992 | EP |
| 2 044 416 | Oct 1980 | GB |
| WO 9420813 | Sep 1994 | WO |
| WO 9420814 | Sep 1994 | WO |
| WO 9924778 | May 1999 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20030121444 A1 | Jul 2003 | US |
| Number | Date | Country | |
|---|---|---|---|
| 60333577 | Nov 2001 | US |
