The present invention relates to primers for firearms and other munitions. More specifically, a cup is provided for containing the ignitable material of a primer, and for holding the ignitable material within a firearm cartridge or within another munition.
Cartridges for firearms, as well as other munitions such as larger projectile cartridges and explosives are often ignited by a primer. Presently available primers and detonators are made from a copper or brass alloy cup with a brass anvil and containing lead azide or lead styphnate. When the base of the cup is struck by a firing pin, the priming compound is crushed between the cup's base and the anvil, igniting the primer charge. The burning primer then ignites another flammable substance such as smokeless powder, explosive substances, etc. Lead azide and lead styphnate are hazardous due to their toxicity as well as their highly explosive nature. Additionally, present manufacturing methods are very labor-intensive, with the necessary manual processes raising costs, causing greater difficulty in maintaining quality control.
Energetic materials such as thermite are presently used when highly exothermic reactions are needed. Uses include cutting, welding, purification of metal ores, and enhancing the effects of high explosives. A thermite reaction occurs between a metal oxide and a reducing metal. Examples of metal oxides include La2O3, AgO, ThO2, SrO, ZrO2, UO2, BaO, CeO2, B2O3, SiO2, V2O5, Ta2O5, NiO, Ni2O3, Cr2O3, MoO3, P2O5, SnO2, WO2, WO3, Fe3O4, COO, Co3O4, Sb2O3, PbO, Fe2O3, Bi2O3, MnO2, Cu2O, and CuO. Example reducing metals include Al, Zr, Th, Ca, Mg, U, B, Ce, Be, Ti, Ta, Hf, and La. The reducing metal may also be in the form of an alloy or intermetallic compound of the above-listed metals.
A properly designed energetic material, for example, that which is disclosed in US 2016/0102030, which was invented by K. R. Coffey et al. and published on Apr. 14, 2016, would provide an effective alternative to presently used primer materials, as well as being safer to manufacture. The entire disclosure of US 2016/0102030 is expressly incorporated herein by reference. In addition to the structures and methods disclosed therein, a primer cup is disclosed herein for easily installing such a primer within a conventional cartridge casing, or within another location that is designed to receive a conventional primer.
The above-described needs are met by a primer. The primer comprises a tube having a side wall. The tube defines a first open end, a second open end, a tube interior, and a central axis. The second open end defines a ledge projecting towards the central axis. The primer further comprises a disk having a first surface, a second surface, and an edge. The disk is dimensioned and configured to fit within the interior of the tube with the periphery of the disk abutting the wall. The disk has an ignitable material deposited upon the first surface. The ledge of the tube is dimensioned and configured to resist passage of the disk therethrough.
The above-described needs are met by a cup for a primer. The cup comprises a tube having a side wall. The tube defines a first open end, a second open end, a tube interior, and a central axis. The second open end defines a ledge projecting towards the central axis. The primer further comprises a disk having a first surface, a second surface, and an edge. The disk is dimensioned and configured to fit within the interior of the tube with the periphery of the disk abutting the wall. The ledge of the tube is dimensioned and configured to resist passage of the disk therethrough.
These and other aspects of the invention will become more apparent through the following description and drawings.
Like reference characters denote like elements throughout the drawings.
Referring to the drawings, an example of a primer cup is shown. The illustrated example of a primer cup may be used with a firearm cartridge, or with another munition that utilizes a primer in any capacity. Although the illustrated example of a primer cup is intended for use with an ignitable material that can be deposited on the disk as described below, for example, a thermite priming material, it is not limited to such use. As used herein, the terms top, bottom, front, back, side, etc. are used for convenience only, and are not intended to limit the scope of the invention. It is recognized that rotation of the components described herein would result in a different portion of each component being a top, side, etc.
The primer cup 10 (
Referring to
Referring to
An example of a process for making the tube 12 begins with malleable metal tubing such as brass tubing having an external diameter corresponding to a typical external diameter for a standard primer. The tube is cut to a length corresponding to or slightly longer than the length of a standard primer. One end of the tube is bent to form the ledge 20. The sidewall 15 of the tube 12 is then crimped to form the inward projections 26.
The disk 14 is made from a sheet of malleable metal, such as a brass sheet. Some examples of the process will form multiple disks 14 simultaneously. A press is utilized to form the disk 14 into the shape that is described above and illustrated in the drawings. Individual discs 14 can be cut from the sheet before or after the pressing process. The thermite may be deposited within the recess 40 either before or after the discs 14 are cut from the brass sheet, depending upon when the pressing process takes place.
Once the disks 14 and tubes 12 are formed, a disk 14 is inserted into the opening 22 of a tube 12, and moved downward within the tube 12 until the second edge portion 38 is within the opening 24, and the first edge portion 36 abuts the ledge 20, and is retained by the inward projections 26. Once the disks 14 are installed within the corresponding tubes 12, an adhesive may be utilized to further secure each disk 14 within its tube 12. Suitable adhesives are known in the art of manufacturing ammunition for firearms. As one example, an anaerobic, UV curable adhesive is known to be drawn into the interface between a conventional primer and casing, and could also be utilized to adhere the disk within 14 to the tube 12. The inward projections 26 may be formed either before or after the disk 14 is positioned inside the tube 12.
The present invention therefore provides a primer that includes an ignitable material deposited thereon. The ignitable material can in some examples be a layered thermite material. The primer can be easily and safely manufactured by depositing the ignitable material on a disk, and then inserting the disk into a tube to form the primer cup. The primer can be dimensioned and configured to fit within a primer pocket of a standard firearm cartridge or the primer pocket of another munition that utilizes standard primers.
A variety of modifications to the above-described embodiments will be apparent to those skilled in the art from this disclosure. Thus, the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention. The appended claims, rather than to the foregoing specification, should be referenced to indicate the scope of the invention.
This application claims the benefit of U.S. provisional patent application Ser. No. 62/579,141, filed Oct. 30, 2017, and entitled “Primer Cup for a Thermite Primer.”
Number | Date | Country | |
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62579141 | Oct 2017 | US |