TWO-PIECE INSERT AND/OR FLASH TUBE FOR POLYMER AMMUNITION CARTRIDGES

Abstract

A high strength polymer-based cartridge casing can include an upper polymer component, molded from a polymer. The upper component has a first end having a mouth, at least a wall between the first end and a second end of the upper component opposite the first end, an overlap portion extending from the wall near the second end. An upper insert is included and has a first end and an opposing second end, a molded area disposed approximate the first end, that engages the overlap portion to join the upper polymer component and the upper insert, and an insert engagement area disposed approximate to the second end. Further, a lower insert has a front end and a back end, an upper insert engagement area engaging with the insert engagement area, a rim and groove disposed around an outside of the lower insert, and a primer pocket disposed inside the back end. Lastly, a flash hole is inside the lower insert and communicates between the primer pocket and upper polymer component.

Claims

1. A high strength polymer-based cartridge casing comprising: an upper polymer component, molded from a polymer, comprising: a front end having a mouth; at least a wall between the front end and a back end of the upper component opposite the front end; and an overlap portion extending from the wall near the back end; an upper insert, having a first end and an opposing second end, comprising: a molded area disposed approximate the first end, that engages the overlap portion to join the upper polymer component and the upper insert; an insert engagement area disposed approximate to the second end; a lower insert, having a top end and a bottom end, comprising: an upper insert engagement area engaging with the insert engagement area; a rim and groove disposed around an outside of the lower insert; a primer pocket disposed inside the bottom end; and a flash hole, inside the lower insert and communicating between the primer pocket and upper polymer component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The file of this patent contains at least one drawing executed in color. Color drawings are necessary because color is an integral part of the claimed design. Copies of this patent with color drawings will be provided by the Office upon request and payment of the necessary fee.

[0033] The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements.

[0034] FIG. 1 is a cross-section of a bottle neck cartridge with a two-piece insert of the present invention;

[0035] FIG. 2 illustrates a side view of an example of the upper component;

[0036] FIG. 3 is a magnified cross-section illustrating an example of the upper component and upper insert of the present invention;

[0037] FIG. 4 is a magnified cross-section illustrating an example of the upper component, upper insert, and lower insert of the present invention;

[0038] FIG. 5 is a cross-section illustrating an example of the upper insert of the present invention;

[0039] FIG. 6 is a side view of an example of a lower insert;

[0040] FIG. 7 is a bottom front perspective view of the lower insert of FIG. 6;

[0041] FIG. 8 is a longitudinal cross-section view of the lower insert of FIG. 6;

[0042] FIG. 9A is a longitudinal cross-section view of example of belted lower insert;

[0043] FIG. 9B is a cross-section view of another example of a basin lower insert installed;

[0044] FIG. 10 is a cross-section view of another example of the upper component, upper insert and lower insert engaged;

[0045] FIGS. 11A and 11B are side and side-back profile views, respectively, of another example of an upper insert;

[0046] FIGS. 12A and 12B are side and side-back profile views, respectively, of another example of a lower insert;

[0047] FIG. 13 is a cross-section of another example of a lower insert;

[0048] FIG. 14 is a cross-section of a example of a crimped lower insert;

[0049] FIG. 15 is a cross-section of yet another example of an upper insert;

[0050] FIG. 16 is a cross-section view of an example of the upper and lower inserts engaged;

[0051] FIG. 17 is an exploded view of the entire cartridge;

[0052] FIG. 18 is a cross-section view of an example of a flash tube;

[0053] FIGS. 19A through 19E each illustrate different examples of flash tubes;

[0054] FIG. 20 is an exploded view of an example of the entire cartridge, including a flashtube; and

[0055] FIGS. 21A and 21B are prior art flash tube structures for brass cartridges.

DETAILED DESCRIPTION

[0056] In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

[0057] The present example provides a cartridge case body strong enough to withstand gas pressures that equal or surpass the strength required of brass cartridge cases under certain conditions, e.g. for both storage and handling. At the same time, the cartridge can be easily produced and still maintain surpass brass cartridges.

[0058] Referring now to FIG. 1, a cross-section of a bottleneck cartridge case 100 is illustrated. The cartridge case 100 includes an upper polymer component 200, an upper insert 300, and a lower insert 400. In this example, the upper polymer component 200 is made of a polymer while the upper and lower inserts 300, 400 are made from a metal, an alloy of metals, or an alloy of a metal and a non-metal. Regardless of materials, the outer dimensions of the cartridge case 100 are within the acceptable tolerances for whatever caliber firearm it is designed to be loaded into.

[0059] The polymer used is lighter than brass. A high impact polymer can be used where the glass content is between 0%-50%. An example of an impact modified polymer is polyetherimide (PEI). Further examples include using polysulfones (PSU), polyphenylsulfone (PPSU), siloxane, polycarbonates, and any co-polymers, alloys or blends of the above.

[0060] The upper and lower inserts 300, 400 can be made of brass or steel, and, in examples, stainless steel. The nature of the features allows examples of the insert to be made of “softer” steel. Other examples use heat treated carbon steel, 4140. The 4140 steel has a rating on the Rockwell “C” scale (“RC”) hardness of about 20 to about 50. However, any carbon steel with similar properties, other metals, metal alloys or metal/non-metal alloys can be used to form the inserts.

[0061] In an example, the upper component 200 is made of high impact polymer combined with the inserts 300, 400 made of brass or steel that result in a cartridge that is approximately 50% lighter than a brass formed counterpart. This weight savings in the unloaded cartridge produces a loaded cartridge of between 25%-30% lighter than the loaded brass cartridge depending on the load used, i.e. which projectile, how much powder, and type of powder used.

[0062] FIGS. 1 and 2 illustrate the upper component 200 with a body 202 which transitions into a shoulder 204 that tapers into a neck 206 having a mouth 208 at a first end 210. The upper component 200 joins the upper insert 300 at an opposite, second end 212. The body 202 generally forms a propellant chamber 203, as this holds the propellant (not illustrated) to propel the projectile (not illustrated) typically fitted into the mouth 208. The propellant chamber 203 can be a volume from the lower insert 400 to approximately the shoulder 204. A bottom of a projectile extends into the mouth 208 and past the neck 206, and this can act as the other “end” to the propellant chamber 203.

[0063] The propellant is typically a solid chemical compound in powder form commonly referred to as smokeless powder. Propellants are selected such that when confined within the cartridge case, the propellant burns at a known and predictably rapid rate to produce the desired expanding gases. The expanding gases of the propellant provide the energy force that launches the projectile from the grasp of the cartridge case 100 and propels the projectile down the barrel of the gun at a known and relatively high velocity.

[0064] Turning to FIG. 3, the upper insert 300 joins the upper component 200 at an upper insert first end 302. The upper insert 300 is formed from a metal, metal alloy or metal/non-metal alloy. It can be formed by any known method in the art, including turning, milling, hydroforming, casting, cold heading, stamping, etc. In one example, when the upper component 200 is molded, it can be molded under or over the upper insert 300. This is a partial molding since the upper component 200 does not completely cover (or is completely subsumed by) the upper insert 300. In some examples, polymer can cover both the outside and inside of the upper insert 300 and thus the polymer may “sandwich” or flow on both sides of the upper insert 300 (not illustrated). In other examples, the upper insert 300 can just be undermolded, as illustrated, for example in FIG. 9B, or overmolded.

[0065] The body 202 includes a wall 214 having a thickness T. The upper component second end 212 has an overlap portion 216, which is the portion of the upper component 200 that engages the upper insert 300. The overlap portion 216 has a thinner wall thickness t, or a second thickness, at the second end 212 than the thickness T of the wall 214 before the overlap portion 216. In examples, this can be an average second thickness as the overlap portion 216 can have bands 218 which can vary the height (see below).

[0066] As illustrated in FIGS. 4 and 5, the upper insert 300 can include an undermolded area 304, where the overlap portion 216 engages the upper insert 300. Note this can also be an overmolded area, where the polymer and metal would just switch sides. The undermolded area 304 has a thickness t.sub.i, which can be taken as an average in examples of the undermolded area 304 that have one or more ridges, ribs, knurling, and/or keys 306. The ridges 306 allow the polymer from the overlap portion 216, during molding, to forms bands 218 (see FIG. 2). The combination of the ridges 306 and bands 218 aid in resisting separation between the upper insert 300 and the upper component 200. The resistance is most important during the extraction of the cartridge 100 from the firearm by an extractor (not illustrated).

[0067] The undermolded area 304, in an example, can include one or more keys (not illustrated). The keys can be flat surfaces on the ridges 306 that can prevent the upper insert 300 and the upper portion 200 from rotating in relation to one another, i.e. the upper insert 300 twisting around in the upper portion 200. Keys are only an example thereof, and other methods can be used to prevent the relative rotation of the two parts. Other examples can be any surface changes, i.e. dimples, teeth, etc., that perform the same non-rotational function.

[0068] The upper insert 300 also has a second end 308 with an insert engagement area 310. The insert engagement area 310 can be the area of the upper insert 300 that engages the lower insert 400. An example of the second end 308 of the upper insert 300 can also have a bevel 312 to ease the insertion of the lower insert 400 into the second end 308.

[0069] Further, the insert engagement area 310 has a thickness Ti and this can be equal to or about equal to the wall thickness T of the body wall 214 (T≈Ti) and is greater than the undermolded area thickness t.sub.i (Ti>t.sub.i). This allows the upper component 200 and the upper insert 300 to be molded in the same mold with the same pin so as the pin can be easily extracted from the second ends 212, 308. If the upper insert engagement area thickness Ti is greater than the body wall thickness T (Ti>T) then the molding pin cannot either properly enter or be extracted from this portion of the molded cartridge. Further to the concept of molding pin insertion, in examples, no barrier can be formed along the length of the upper portion 200. The body 202 can be hollow and uninterrupted from the mouth 208 to the second end 212.

[0070] In comparing all of the thicknesses, the examples focus on the wall thickness T, the upper insert engagement area thickness Ti, the overlap portion wall thickness t, and the undermolded (overmolded) area thickness t.sub.i. As described above, one object of the invention is to allow molding a bottleneck polymer cartridge 100 with a single molding pin removed from the second ends 212, 308. Thus, the sum of the overlap portion wall thickness t and the undermolded area thickness t.sub.i should not exceed either the wall thickness T or the upper insert engagement area thickness Ti. In mathematical terms T≈Ti≈(t+t.sub.i). The values can be exactly equal, or within enough tolerances to allow the molding pin to be inserted on the inside for molding, and the outside dimensions allow the cartridge to be chambered in a weapon chambered for the particular caliber.

[0071] Said differently, that the discussions of examples of thicknesses herein are how thick the interior segments of the element are. The outside dimensions on the cartridge case 100 are typically within the tolerances of cases for a particular caliber projectile.

[0072] Turning to the insert 400, as illustrated in FIGS. 6-9, a back end 402 of the insert 400 is also the rear end of the casing 100. The insert 400 is formed with an extraction groove 404 and a rim 406. The groove 404 and rim 406 are dimensioned to the specific size as dictated by the caliber of the ammunition. The insert 400 can be formed by turning down bar stock to the specific dimensions, cold formed, cold formed and turned to produce the final design.

[0073] The insert 400 includes an upper insert engagement area 408, where the insert engagement area 310 engages the insert 400. The upper insert engagement area 408 can be smooth, have one or more ridges, threads, snaps, etc. 410. The upper insert engagement area 408 allows for a metal-on-metal connection between the upper and lower inserts 300, 400. This connection can be bonded (e.g., adhesives, welds, etc.) and/or mechanical (e.g., friction fit, snap, threading, interference fit, press fit, etc.) or any other metal-on-metal bonding known to those of ordinary skill. The strength of this bond is most important during the extraction of the cartridge from the firearm by an extractor (not illustrated).

[0074] The upper insert engagement area 408 can also include a polymer engagement area 412. The polymer engagement area 412 can be any structure that further engages the polymer of the body wall 214. In one example, the engagement can be at the overlap portion 216. This polymer engagement area 412 can add to the strength of maintaining the lower insert 400 engaged with the cartridge 100. Also, the polymer engagement area 412 can prevent the insert 400 and the upper component 200 from rotating in relation to one another, i.e. the insert 400 twisting around. Keys are only an example thereof, and other methods can be used to prevent the relative rotation of the two parts. Other examples can be any surface changes, i.e. dimples, teeth, etc., that perform the same non-rotational function.

[0075] Furthermore, the polymer engagement area 412 “pinches” against the overlap portion 216 and can act as a gasket, preventing gases from getting between the polymer of the body 202 and the upper component 300. This gasket effect keeps the polymer that flows into undermolded area 304 from separating away from the insert engagement area 310.

[0076] In another example, below the upper insert engagement area 408, toward the back end 402, is a self reinforced area 414. This portion extends to the back end 402 of the lower insert 400 and includes the extraction groove 404 and rim 406. The self reinforced area 414 must, solely by the strength of its materials, withstand the forces exerted by the pressures generated by the gasses when firing the projectile and the forces generated by the extractor. In the present example, the self reinforced area 414 withstands these forces because it is made of a heat treated metal or a metal/non-metal alloy.

[0077] FIGS. 7 and 8 illustrate an example of the inside of the lower insert 400. Open along a portion of the back end 402 and continuing partially toward the upper insert engagement area 408 is a primer pocket 416. The primer pocket 416 is dimensioned according to the standards for caliber of the cartridge case and intended use. A primer (not illustrated) is seated in the primer pocket 416, and when stricken causes an explosive force that ignites the propellant (not illustrated) present in the upper component 200.

[0078] Forward of the primer pocket 416 is a flash hole 418. Again, the flash hole 418 is dimensioned according to the standards for the caliber of the cartridge case and intended use. The flash hole 418 allows the explosive force of the primer, seated in the primer pocket 418, to communicate with the upper component 200.

[0079] In another example, forward of the primer pocket 416 and inside the upper insert engagement area 408 can be a basin 420. The basin 420 is adjacent to and outside of the inner bowl 314 of the lower component 300. The basin 420 is bowl shaped, wherein the walls curve inwards toward the bottom. The bottom of the basin 420 is interrupted by the flash hole 418.

[0080] The example of FIG. 9 also includes a belted lower insert 400. The belt 424 can be used to provide headspacing and has a larger outer diameter than the lower component's outer wall. Belted cartridges are used primarily in “magnum” rounds and in some cases to prevent the higher-pressure magnum cartridge from accidentally being chambered in a gun with a chamber of similar size.

[0081] The present example can also use, either with or without providing headspacing, the belt 424 as stopping point of the upper insert engagement area 408. Another feature of the lower insert 400 is two ridges 410, to reduce the amount of the insert that is required to be upper insert engagement area 408 by the upper insert 300.

[0082] The belt 424 can also be used to stop the insertion of the lower insert 400 into the upper insert 300. The belt 424 can engage the bottom of the bevel 312 and act as a stop.

[0083] FIG. 9A further illustrates an example using two ridges 410, instead of three ridges 410 as illustrated and discussed above. In the illustrated two ridge design, the first ridge 410A is wider than the second ridge 410B, to provide the additional surface area that is lacking if there are three or more ridges. The width differential can be approximately 2 to 4 times larger. The ridged design increases the pull strength to separate the lower insert 400 from the upper insert 300, providing additional strength to extract the empty cartridge after firing. Further to the two ridge example, it is easier to machine the insert than the three ridge version, but both are still feasible.

[0084] FIG. 9B illustrates a smooth walled “basin” lower insert 400 in cross-section. This example of the lower insert 400 does not have ridges 410. The fit between the upper and lower inserts 300, 400 can be mechanical friction, or any of the other ways noted above. Also illustrated is second bevel 426 on the lower insert 400. The second bevel 426 also aids in the insertion of the lower insert 400 into the upper insert 300. This second bevel 426 is sloped opposite the basin 420.

[0085] FIGS. 10-12 illustrate another example with smoother surfaces. As illustrated, the lower insert 400 does not cover the polymer of the overlap portion 216. Further, the top face 421 of the lower insert 400 is “flat”. FIGS. 6-9 illustrated an example with the basin 420, this example does not have a basin 420. FIGS. 11A and 11B illustrate another example of the upper insert 300. This illustrates a top bevel 316 to aid in molding. FIGS. 12A and 12B illustrate another example of the lower insert 400. Here, the upper insert engagement area 408 can be smooth and can form an interference fit with the upper insert 300. Further, in this example, the lower insert 400 can only have a rim 406. The extraction groove 404 can be formed from the spacing between the rim 406 and the upper insert 300 and does not need to be machined into the lower insert 400. This can save manufacturing costs.

[0086] In examples, the upper and lower inserts 300, 400 engage around the inside of the upper 300 and the outside of the lower 400. The upper insert 300 does not contact, or act as an extension of, the flash hole 418.

[0087] FIG. 13 illustrates another cross-section of a lower insert 400. Here the belt 424 and the groove 404 are similar, where the true stopping point for the insertion of the lower insert 400 into the upper insert 300 is at the edge of the belt, also noted 424. FIG. 14 illustrates the lower inset 400 with a crimp ring 422. The crimp ring 422 can be set, in certain examples, above the belt 424. Once the upper and lower inserts 300, 400 are engaged, the bevel 312 of the upper insert can be crimped into the crimp ring 422. This can be used to increase the strength of the engagement between the upper and lower inserts 300, 400.

[0088] FIG. 15 is a cross section of the upper insert 300 prior to engagement with the lower insert 400 and FIG. 16 is another example of the upper and lower inserts 300, 400 engaged. FIG. 17 is an exploded view of the cartridge 100, where the upper component 200 is undermolded into the upper insert 300 and the lower insert 400 is then inserted into the upper component 300.

[0089] FIG. 18 introduces another element to the lower insert 400, a flash tube 500. The flash tube 500 can come up from the flash hole 418, through the primer pocket 416 and into the propellant chamber 203. The flash tube 500 can extend any distance into the propellant chamber 203. In examples, the flash tube 500 extends approximately between 50-90% of the propellant chamber, with other examples at approximately ⅔ or ¾ (˜66% and ˜75%) of the distance to the shoulder 204 or bottom of the projectile.

[0090] FIGS. 19A through 19E illustrate separate examples of the flash tube 500. The flash tube 500 has a propellant chamber end 502 and an opposite insert engagement end 504. The flash tube 500 is hollow and extends from the primer pocket 416. FIGS. 19A and 19B illustrate examples where the flash tube 500 is vented using holes. Vent holes 506 perforate the flash tube 500 and can be spaced in any pattern around the flash tube 500 from a single hole to multiple holes around a single perimeter to multiple rows/columns of holes extending along the flash tube 500. FIGS. 19C and 19D illustrate the vent holes as slits 506A. In FIG. 19C, the slits 506A are only at the top portion of the flash tube 500. FIG. 19D illustrates multiple slits 506A in a spaced pattern. FIG. 19E illustrates an example that the flash tube 500 can be solid and a single vent hole 506B can be at the propellant chamber end 502 at the “top”. In addition, examples can combine vent holes 506 to include slits 506A and top hole 506B. None of the above is limiting to the size and shape of the venting 506, as any size, shape, and pattern can be used to vent the primer blast.

[0091] FIGS. 19A and 19C-E illustrate a washer end 508 to the insert engagement end 504. The washer end 508 is sized to be approximately the same diameter as, or smaller than, the primer pocket 416. FIG. 19B illustrates a threaded end 510 to the insert engagement end 504. In this example the flash tube 500 and the lower insert 400 and/or primer pocket 416 can be joined by a threaded arrangement. The matching threads on the lower insert 400 can be in multiple places. In one example, the matching threads can be inside the flash hole 418 or after the flash hole 518 toward the propellant chamber 203. Note that while a press fit and threaded engagement are illustrated and described, this is not limiting to the ways known to attach the two elements.

[0092] FIG. 20 illustrates an example of engaging the flash tube 500 which can involve inserting the propellant chamber end 502 through both the primer pocket 416 and the flash hole 418 until the washer end 508 is stopped by where the primer pocket 416 ends. In this example, the flash tube 500 takes all of the primer charge and the flash hole 418 can be said not to be used. As above, the flash tube 500 and the lower insert 400 and/or primer pocket 416 can be joined by bonding (e.g., adhesives, welds, etc.), mechanical processes (e.g., friction fit, snap, threading, interference fit, press fit, etc.) or any other metal-on-metal bonding known to those of ordinary skill. Alternately, the flash tube 500 can be fitted up through the primer pocket 416 and flash hole 418 and then screwed into place or can be inserted from the top, or the mouth 208, and screwed in on top of the lower insert 400. In all regards, the flash tube 500 is fluidly connected to the primer pocket 416 so that the primer ignition passes from the primer pocket 416 and out the vent hole 506 to ignite the propellant in the propellant chamber 203. The flash tube 500 can pass it directly or it can first pass through the flash hole 418 and into the flash tube 500.

[0093] All examples contemplate that the flash tube 500 can be preassembled to the lower insert 400 before the lower insert 400 is engaged to the upper insert 300 or assembled after engagement. Additionally, the flash tube 500 can be manufactured directly into the lower insert 400, removing extra assembly steps.

[0094] As noted above, the use of a flash tube 500 can reduce the amount of propellant needed to generate a given pressure in comparison to the amount of propellant needed without the tube 500. This allows for different configurations where more propellant is used (to fill the propellant chamber 203) to increase pressures and increase the velocity of the discharged projectile. Alternately, the size of the propellant chamber can be reduced to accommodate the reduced propellant load. These reductions can extend to not only typical ammunition, but blank and subsonic ammunition, reducing the propellant load even further. See, at least U.S. Pat. Nos. 8,763,535 and 9,003,973, which are incorporated herein by reference.

[0095] While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.