Patent Application
20210102791
This disclosure relates to primers for munitions, and more particularly, to scalable, electrically initiated primers for major caliber gun systems that improve the survivability of a propelling charge system exposed to insensitive munitions (IM) stimuli.
Charges for major caliber guns with high-energy properties can raise safety concerns due to the risk that unplanned or inadvertent stimuli could cause unwanted ignition of the propelling charges. Primers that increase the safety of such charges have been desired and sought by those in the industry. Specifically, there remains a need for a major caliber gun propellant ignition device (primer) that supports the safety of multiple munitions applications across a variety of platforms. For example, support for non-conventional variants of projectiles, some with mid-body obturators, is desired as such variants complicate propelling charge interchangability.
In general, a design that uses common components between versions is desired for improved affordability and reliability. Further, a design that uses commercially available energetic materials and commercially available shipping methods is desired to reduce reliance on special military documentation and requirements.
In minor caliber applications, prior art primers have been used in 57 mm encased ammunition (Bofors 3P) to reduce the IM response of the system when combined with other system features, such as a brass cartridge case or pressure release feature. However, major caliber cartridges of the prior art generally have failed IM tests.
Accordingly, a there is a desire for a safe and scalable primer for major caliber gun systems that improve the survivability of a propelling charge system.
Embodiments generally relate to scalable, electrically initiated, IM primers for major caliber gun systems. Embodiments of IM primers improve the survivability of propelling charge systems to IM stimuli and support a plurality of system level requirements. Some embodiments of IM primers can support multiple munitions applications in a variety of platforms. Some embodiments of IM primers utilize commonality of component between versions to improve affordability and reliability. Some embodiments of IM primers use commercially available energetic materials and shipping methods which can reduce reliance on special military documentation. Embodiments can provide prompt, robust, and controlled hot gas output to ignite gun propellant without generating pressure waves. Embodiments provide a primer designed to effect a controlled response to IM stimuli that improves safety of a system in transportation and storage.
An embodiment relates to an IM primer for use with major caliber gun systems, including an elongate housing, a tube, an ignition assembly, and a booster assembly. The elongate housing has a proximal end and a distal end. The tube has a first end coupled within the distal end of the elongate housing. The ignition assembly is located within the proximal end of the housing. The booster assembly is located within the elongate housing adjacent the ignition assembly and including a booster holder providing a cylindrical structure defining an internal bore in which a first burst disk resides and is mechanically restrained by a booster disk lock.
In some embodiments, the distal end of the elongate housing surrounds an adapter that interfaces between the elongate housing and the first end of the tube, wherein the adapter includes a second burst disk.
An embodiment relates to an IM primer for use with major caliber gun systems, including an elongate housing coupled with a tube of narrower cross section. The housing and the tube define a centrally located bore of varying dimension and features. The bore includes an ignition assembly, a booster assembly having a first burst disk, and an adapter having a second burst disk. The first burst disk and the second burst disk are mechanically, bidirectionally, retained in place.
The above summary is not intended to describe each illustrated embodiment or every implementation of the subject matter hereof. The figures and the detailed description that follow more particularly exemplify various embodiments.
Subject matter hereof may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying figures, in which:
While various embodiments are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the claimed inventions to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims.
Embodiments disclosed generally provide a scalable, electrically initiated, IM primer 10 for major caliber gun systems. In general the IM primer 10 improves the survivability of propelling charge systems to IM stimuli among other features. For example, an IM primer 10 can effect a controlled response to IM stimuli that improves safety of a system in transportation and storage.
Second burst disk 180 is generally a thin circular member that helps reduce or prevent flame propagation via the IM primer 10. In some embodiments, first burst disk 150 is similar to second burst disk 180. In some embodiments, however, first burst disk 150 is more robust than second burst disk 180, and is not crimped like second burst disk 180. The burst disks can resist external pressure to several hundred PSI.
Second burst disk 180 generally isolates the primer energetic material from any reaction of the main propellant until a substantial amount of the propellant has been consumed in the ignition resulting from IM stimuli. The diameter of the disk 180 is sized for compatibility with the interior dimensions of the housing 100 and its burn chamber. The second burst disk 180 is generally retained between the burn chamber and the primer adapter 170.
In
The housing 100 can contain and utilize class 2 black powder as the primary energetic material. Black powder is advantageous as it can generally be legally transported as a flammable solid, without a government IHC. The burn chamber of the housing 100 can be sized to hold as much as 40 grams of black powder. Charge masses of 20 g or 30 g can provide adequate burn pressure and duration in some embodiments.
In
In general, the outside of the cylindrical body portion 173 is intended for insertion within the distal end of the housing 100 of an IM primer 10. The outwardly projecting head portion 175 is to reside outside the housing 100 and abut up against its end. A second burst disk 180 fits within the bore 172 at the intersection of the two bores 172a and 172b. At this location, the second burst disk 180 is held up against an internal annular lip 177. Further, the tube 200 of the IM primer 10 is intended to couple within the bore 172 and, more specifically, be located within the bore 172b such that it abuts up against the second burst disk 180. This arrangement permits advantageous mechanical retention of the second burst disk 180.
In
Tube 200 is generally fabricated from high pressure tubing. Tube 200 has an outer diameter that is compatible to fit within the adapter 170 and corresponding smaller center bore 208. Along the length of the tube 200 are spaced apart air vents 206. In some embodiments, there can be seventeen vent holes 206, for example. The cross-sectional area of all these air holes may be similar to the cross-sectional area of the adapter 170 in some embodiments. Based on the air flow permitted through the tube 200, the initial flow restriction is generally created by the adapter 170. Various lengths of tube 200 are possible. In some examples, an eleven inch tube can be used. The inlet to the tube 200 and the tube air vents 206 are sizeable to sustain and distribute gas generate during high pressure burning of the primary energetic. The length of the tube 200 is adjusted to the end use to protect it and the housing from external mechanical forces. It is also noted that the mass of the primary energetic is also scalable for larger volume propelling charge cartridge volumes. In one example, the IM primer 10 can be used with five inch propelling charges. However, other size charges for major caliber gun systems can be used as well. The distal second end 204 of the tube 200 contains a set screw 210. Accordingly, the distal interior at second end 204 is adapted for receiving a threaded set screw 210.
In general, the overall IM primer 10 is safe to assembly and handle using standard workplace practices. The ignition assembly 110 and booster assembly 120 can be installed sequentially into the burn chamber defining the interior bore of the housing 100 using special spanners. The primer tube 200 with corresponding second burst disk 180 and adapter 170 become a completely inert subassembly that is attached to the burn chamber after it is filled with the specified mass of black powder. The igniter is HERO safe after installation in the cartridge case. Further, many of the components of the IM primer 10 are reusable after minor disassembly and cleaning operations.
Various embodiments of systems, devices, and methods have been described herein. These embodiments are given only by way of example and are not intended to limit the scope of the claimed inventions. It should be appreciated, moreover, that the various features of the embodiments that have been described may be combined in various ways to produce numerous additional embodiments. Moreover, while various materials, dimensions, shapes, configurations and locations, etc. have been described for use with disclosed embodiments, others besides those disclosed may be utilized without exceeding the scope of the claimed inventions.
Persons of ordinary skill in the relevant arts will recognize that the subject matter hereof may comprise fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not meant to be an exhaustive presentation of the ways in which the various features of the subject matter hereof may be combined. Accordingly, the embodiments are not mutually exclusive combinations of features; rather, the various embodiments can comprise a combination of different individual features selected from different individual embodiments, as understood by persons of ordinary skill in the art. Moreover, elements described with respect to one embodiment can be implemented in other embodiments even when not described in such embodiments unless otherwise noted.
Although a dependent claim may refer in the claims to a specific combination with one or more other claims, other embodiments can also include a combination of the dependent claim with the subject matter of each other dependent claim or a combination of one or more features with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a specific combination is not intended.
Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. Any incorporation by reference of documents above is further limited such that no claims included in the documents are incorporated by reference herein. Any incorporation by reference of documents above is yet further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein.
For purposes of interpreting the claims, it is expressly intended that the provisions of 35 U.S.C. § 112(f) are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.
