Cartridge assembly having an integrated retention system

A cartridge assembly for large bore gun systems having an integrated retention assembly for maintaining propellant charges within the cartridge case. The cartridge case having an interior space for receiving propellant charges and an open proximate end through which the propellant charges can be fed. An insulating sleeve defining an interior channel is affixed to the cartridge case and extends out of the proximate end of the cartridge case. The interior channel serves as a chute through which propellant charges can be fed. After the propellant charges are loaded, the insulating sleeve is crimped closed to retain the propellant charges within the cartridge case. A closure plug can be inserted into the proximate end of the cartridge case after the insulating sleeve is crimped closed.

FIELD OF THE INVENTION

The present invention is generally directed to an apparatus and related methods for retaining propellant charges within cartridge cases during loading and firing of gun systems. More specifically, the present invention is directed to a cartridge assembly having an integrated retention system for retaining propellant charges within cartridge cases for use in gun systems having automated loading systems.

BACKGROUND

Large land based artillery and naval gun systems often employ a multi-step loading process in which the projectile and the propellant charge are separately loaded into the firing chamber and subsequently mated together within the firing chamber. Separately loading the propellant charges allows operators of a gun system to adjust the amount of propellant loaded depending on the intended travel distance of the projectile and other firing conditions. Propellant charges can be loaded as a single charge or as a plurality of smaller charges depending on the firing requirements. While separately loading the propellant charges significantly increases the flexibility of long ranged gun systems, the introduction of automated reloading systems and new strategies for using gun systems have created new problems not previously encountered that may interfere or conflict with the traditional multi-step loading process.

In many gun systems, the propellant charges are first loosely loaded into a cartridge case before the entire cartridge assembly is loaded into the firing chamber and mated to the projectile. The cartridge case may include an integrated primer for igniting the propellant charges. Wadding or a plug is often placed over the opening of the cartridge case to ensure that the maximum force of the generated gases from the ignited propellant charges is directed against the projectile. The wadding or plug assists in sealing the expanding propellant gases behind the projectile. While preloading the propellant charges into a cartridge case simplifies the reloading process by allowing operators or automated reloading machinery to handle a single cartridge assembly instead of a plurality of small charges, maintaining the propellant charges within the cartridge case during loading is often difficult.

During loading, a cartridge assembly is chambered by either a manual or a powered ramrod to ram the cartridge assembly into the firing chamber and against the projectile. As the propellant charges for large gun systems can often weigh dozens of pounds, the inertia of the moving propellant charges can cause the propellant charges to continue moving forward even after the rim of the cartridge case is abutted to the base of the projectile. The forward motion of the propellant charges can cause the cartridge cap or wadding to be displaced or the propellant charges to escape the cartridge case.

Propellant charges can be preloaded into a combustible bag before the charges are placed in the cartridge case to help keep the propellant charges together during loading and firing. However, this approach adds an additional step to the reloading process, potentially increasing the reloading time of the gun system. Furthermore, fitting the combustible bag over the propellant charges and within the cartridge case without blocking the interface between the projectile and the cartridge case can be difficult. The presence of a primer in the cartridge case can also interfere with the use of the bag. As such, there is still room for improvement in within cartridge cases.

SUMMARY OF THE INVENTION

The present invention is directed to a cartridge assembly for large bore gun systems such as artillery pieces and naval guns. The invention includes an integrated retention assembly for maintaining propellant charges within the cartridge case. A cartridge case generally includes an elongated body defining an interior space for receiving a propellant charge and having an open proximate end through which the propellant charge can be fed. The proximate end is located closest to the projectile when the cartridge case is chambered in the gun.

The advent of automated reloading systems has significantly shortened reloading times in gun systems. However, the rapid reloading capabilities provided by automated reloading systems have also created significant safety risks. An automated reloading system allows a single gun system to fire multiple projectiles in rapid succession, often before the firing chamber has an opportunity to cool from the previously fired rounds. As propellant charges are combustibles that can ignite when exposed to high temperatures, the propellant charges can prematurely ignite if the cartridge cap is displaced, exposing the propellant charges inside the cartridge case to high temperatures or if the propellant charges escape the cartridge case and come into contact with the hot interior walls of the firing chamber.

Sometimes guns misfire. In a misfire the propellant charge does not properly ignite. Removing misfired or unfired propellant charges from the firing chamber can also create a risk of unintended ignition, if the propellant charges spill from the cartridge case as the misfired cartridge case is extracted from the firing chamber and contact hot surfaces within the firing chamber if the gun has been previously fired.

According to an embodiment of the invention, an insulating sleeve defining an interior channel is affixed to the cartridge case and extends out of the open proximate end of the cartridge case prior to loading of the propellant. The interior channel serves as a chute through which propellant charges can be inserted into the cartridge case. After the propellant charges are loaded, the insulating sleeve is gathered or folded and crimped closed to retain the propellant charges within the cartridge case.

In an example embodiment, the insulating sleeve is formed from a high tensile strength, insulating material that secures the propellant charge and inhibits the propellant charge from moving toward the proximate end of the cartridge case during loading of a cartridge or extraction of a misfired cartridge case. The insulating sleeve also insulates the propellant charges from hot gases and surfaces within the firing chamber when the cartridge case is loaded into a hot firing chamber.

According to an embodiment of the invention, a high tensile strength strap can be used to secure and crimp the insulating sleeve closed at its proximate end. In another aspect of the invention, an adhesive strip can be affixed to the insulating sleeve to reinforce the high tensile strength strap to assist in securing the insulating sleeve against opening during loading of the cartridge or extraction of a misfired cartridge. High strength and temperature resistant adhesive or adhesive tape is used to affix the insulating sleeve to the cartridge case and help keep the insulating sleeve closed.

According to an embodiment of the invention, a closure plug can be inserted into the proximate end of the cartridge case to assist in efficient use of the gases generated by the ignited propellant charges. According to an embodiment of the invention, the closure plug can include a distal conical indent or other space defined for receiving the crimped portion of the interior bag so that the closure plug evenly sits in the proximate end of the cartridge case. The closure plug can also have a proximate conical indent or other shaped indentation for interfacing with certain irregularly shaped projectiles.

The above summary of the various representative embodiments of the invention is not intended to describe each illustrated embodiment or every implementation of the invention. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the invention. The figures in the detailed description that follow more particularly exemplify these embodiments.

DETAILED DESCRIPTION OF THE FIGURES

As depicted inFIG. 1, cartridge assembly10according to an example embodiment of the invention includes cartridge case12, at least one propellant charge14, and retaining assembly16. The cartridge case12comprises generally cylindrical elongated body18defining interior space20for receiving propellant charge14and having open proximate end22and closed distal end24. Cylindrical for the purposes of this application includes tapered cartridge cases12. Cartridge case12is generally formed of metal, such as, for example, brass. Elongated body18further presents interior surface26and exterior surface28. According to an embodiment of the invention, cartridge case12further includes commonly includes primer25extending through the distal end24of the cartridge case12and projecting into interior space20.

Propellant charge14can be formed as a single unitary propellant charge as depicted inFIG. 1or be made up of a plurality of individual propellant charge units packed within cartridge case12. Propellant charge14can be solid or granular. According to one embodiment of the invention, the total weight of propellant charge14does not exceed about 28.5 kg. This should not be considered limiting.

Retaining assembly16includes insulating sleeve30and closure member32. Insulating sleeve30has a generally cylindrical shape surrounding and defining interior channel34and having open proximate end36and open distal end38. Flexible insulating sleeve30may be formed from insulating Kevlar mesh, wool/rayon blend or any other insulating material having sufficient tensile strength to retain the propellant charge14under the acceleration expected during loading, ramming and handling of cartridge assembly10. In an example embodiment, insulating sleeve30is formed from 0.030″ Kevlar netting.

In one example embodiment, insulating sleeve30further includes adhesive strip40disposed on the exterior of insulating sleeve30near the distal end thereof. Other forms of adhesive may be used as well, such as hot melt adhesives. Or, adhesives may be applied to or integrated into insulating sleeve30. Adhesive strip40, according to one embodiment of the invention, can include an adhesive tape such as, but not limited to, the 3M-1099 and 3M-DP-460 tape products produced by the 3M Corporation of St. Paul, Minn.

Closure member32is adapted to crimp closed proximate end36of insulating sleeve30and retain propellant charge14within cartridge case12. Closure member32may include first tie33made of, for example, Kevlar parachute cord, a nylon tie, or any other closing means having sufficient tensile strength to secure closed proximate end36of insulating sleeve30from reopening during loading, handling and extraction of cartridge assembly10. In an example embodiment, closure member32can further include second tie35to further reinforce first tie33. According to another embodiment of the invention, second adhesive strip42is disposed on the interior of insulating sleeve30at proximate end36. Adhesive strip42may form a part of closure member32securing proximate end36of the insulating sleeve30from reopening or may be used alone to secure proximate end36of the insulating sleeve30from reopening.

As shown in FIGS.1and4-8, the cartridge assembly10can further include closure plug44insertable into proximate end of cartridge case12. Closure plug44assists in inhibiting the leakage of gases generated by the ignited propellant charge14and helps to ensure that the maximum amount of force is applied to projectile4.

In one embodiment, depicted inFIGS. 4-6, closure plug44includes exterior wall46having proximate end48and distal end50. Distal end50of closure plug44is dimensioned to be insertable into proximate end22of cartridge case12. According to an example embodiment, adhesive strip52may be disposed at distal end50of exterior wall46between closure plug44and inner surface26of cartridge case12. According to one embodiment, closure plug44can be formed to have a solid body.

According to another embodiment, as depicted inFIGS. 6 and 8closure plug44defines interior space54therein and a plurality of ribs56within closure plug44. Ribs56include anterior reinforcement ribs58within proximal end48generally perpendicular to exterior wall46. Anterior reinforcement ribs58may taper from radially to centrally as seen inFIGS. 6 and 8and may abut proximate conical indent60centrally located in closure plug44. Proximate indent60is depicted as conical in shape but may be of any shape and may be formed to complementarily mate to a base of a projectile (not shown) such as a sabot projectile known to those of skill in the art. Proximate indent60partially defines projectile space61.

Closure plug44may also present supporting arms62and central ring64. As best seen inFIG. 8, arms62extend inwardly from exterior wall46and coupled to central ring64. Arms62may extend proximately and centrally from exterior wall46to central ring64. Arms62may be radially located approximately half way between anterior reinforcement ribs58as depicted inFIG. 8. Arms62and anterior reinforcement ribs58may number five each as depicted but this should not be considered limiting. Central ring64may present angled ring wall66. Optionally, closure plug44may include generally planar distal wall68.

Referring toFIG. 7, according to another embodiment of the invention, distal end52of closure plug44further includes formed wall70. Formed wall70presents peripheral portion72, intermediate taper74and centrally located distal conical indent76. Peripheral portion72mates with exterior wall46. Exterior wall46may present anterior taper78and planar nose80. In this embodiment closure plug44present a generally closed structure with internal ribs56including anterior reinforcement ribs58and posterior reinforcement ribs82. In this embodiment, closure plug presents annular mating indent84and thickened reinforcing ring86. Anterior reinforcement ribs58and posterior reinforcement ribs82extend generally radially and may alternate circumferentially as depicted inFIG. 7.

Referring toFIG. 9, the invention may also include foam wadding88inserted between closure plug44and insulating sleeve30. For example, 1.5 inch ESD foam wadding maybe inserted behind closure plug44.

Closure plug44may be formed for example, from Torlon 42031L material. In another example embodiment, interior space54between exterior wall46and distal wall68or formed wall70may be filled with low density ESD foam.

The invention also includes a method of loading propellant charge14into cartridge case12including securing open distal end38of sleeve30to interior surface26of cartridge case12then extending open proximate end36of sleeve30outwardly from proximate end22of cartridge case12followed by inserting at least one portion of propellant charge14into cartridge case12through the open proximate end36of sleeve30. The method further includes gathering open proximate end36of sleeve30within proximate end22of cartridge case12and closing the second open end of sleeve30within cartridge case12and securing the second open end of sleeve30within cartridge case12with closure member.

The method may further include securing open proximate end36closed with first tie33. Securing open proximate end36closed with first tie33may include tying gathered open proximate end36closed. The method may also include securing the open proximate end36closed with an adhesive such as second adhesive strip42.

The method may include securing open proximate end36of sleeve30to interior surface26of cartridge case12by positioning second adhesive strip42between sleeve30and interior surface26of cartridge case12.

The method may include inserting closure plug44into proximate end22of cartridge case12. The method may also include applying second adhesive strip42between closure plug44and open proximate end36of cartridge case12.

The method may include selecting the closure plug to present distal conical indent76and/or proximate indent60.

In operation, Referring toFIGS. 2-3and6-7, insulating sleeve30is affixed to the inner surface26of the cartridge case12by adhesive strip40or another adhesive such that insulating sleeve30forms a chute through which propellant charge14can be inserted. After a desired amount of propellant charge14is inserted through interior channel34of insulating sleeve30and packed into interior space20of cartridge case12, proximate end36of insulating sleeve30is gathered and crimped or secured closed with closure member32. A portion of insulating sleeve30and closure member32can protrude beyond proximate end36of propellant charge14. According to an embodiment of the invention, second adhesive strip42can be used to further secure closed proximate end36of insulating sleeve30or be used alone to secure sleeve30closed. After proximate end36of insulating sleeve30is closed, cartridge assembly10can be rammed into a firing chamber such that proximate end22of cartridge case12interfaces with a base portion of a projectile (not shown). Insulating sleeve30arrests the forward motion of propellant charge14at the termination of the ramming of cartridge case12to prevent propellant charges14from escaping cartridge case12.

The insulating material of insulating sleeve30also insulates the propellant charge14from possible high temperatures and hot surfaces in the firing chamber during loading and extraction of a misfired cartridge assembly10

When closure plug44is used, closure plug44is inserted into open proximate end22of cartridge case12. Closure plug44may be secured by second adhesive strip42inserted between closure plug44and cartridge case12. When closure plug44as depicted inFIGS. 6 and 8is used, closure member32and open proximate end36after having been secured by closure mechanism32may fit into projectile space61if present. When closure plug44as depicted inFIG. 7is used with cartridge case12, open proximate end36of insulating sleeve30may be positioned in projectile space61defined by distal conical indent76.

After a closure plug44is inserted into cartridge case12, proximate end22of cartridge case12may be crimped into mating indent84of closure plug44.

EXAMPLES

Cartridge assembly10including a closure plug44as depicted inFIG. 7was tested utilizing an inert propellant charge14. Inert propellant charge14had a mass of 28.5 kilograms and was positioned with 1.5 inches of clearance between closure plug44and propellant charge14. Insulating sleeve30was formed of wool/rayon, bonded to cartridge case12, interior surface26with 3M-1099 adhesive. 1.5 inches of foam wadding88was placed between propellant charge14and closure plug44and cartridge assembly10was rammed at 10.0 meters per second. Under these circumstances, movement of closure plug44was limited to 0.142 inches. In another test, closure plug44moved 0.077 inches after 2 ram tests. Closure plug44remained intact and inert propellant charge14was retained.

In another test, an inert propellant charge14having a mass of 28.5 kilograms was positioned with 0.5 inches clearance between it and closure plug44as depicted inFIG. 7. Insulating sleeve30was formed of 0.30 inch Kevlar netting and the prepared cartridge assembly10was rammed at 10.5 meters per second. Under these circumstances, closure plug44moved 0.143 inches after one ram test. Closure plug44remained intact and inert propellant charge14was retained.

In another test, a 28.5 kilogram inert propellant charge14was secured inside insulating sleeve30made of 0.30 Kevlar netting and added Kevlar cord was used as first tie33to secure insulating sleeve30. Closure plug44as depicted inFIGS. 6 and 8was utilized permitting a 2.0 inch space between inert propellant charge14and closure plug44. Under these circumstances, impact between inert propellant charge14and closure plug44was prevented.

Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement calculated to achieve the same purpose could be substituted for the specific examples shown. This application is intended to cover adaptations or variations of the present subject matter. Therefore, it is intended that the invention be defined by the attached claims and their legal equivalents, as well as the following illustrative embodiments.