U.S. patent application number 15/482068 was filed with the patent office on 2018-10-11 for two-piece insert and/or flash tube for polymer ammunition cartridges.
This patent application is currently assigned to PCP Tactical, LLC. The applicant listed for this patent is PCP Tactical, LLC. Invention is credited to Charles PADGETT, Lanse PADGETT.
Application Number | 20180292186 15/482068 |
Document ID | / |
Family ID | 63711314 |
Filed Date | 2018-10-11 |
United States Patent
Application |
20180292186 |
Kind Code |
A1 |
PADGETT; Charles ; et
al. |
October 11, 2018 |
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.
Inventors: |
PADGETT; Charles; (Vero
Beach, FL) ; PADGETT; Lanse; (Vero Beach,
FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PCP Tactical, LLC |
Vero Beach |
FL |
US |
|
|
Assignee: |
PCP Tactical, LLC
Vero Beach
FL
|
Family ID: |
63711314 |
Appl. No.: |
15/482068 |
Filed: |
April 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F42C 19/083 20130101;
F42B 5/307 20130101; F42C 19/0826 20130101 |
International
Class: |
F42B 5/307 20060101
F42B005/307; F42C 19/08 20060101 F42C019/08 |
Claims
1. (canceled)
2. A high strength polymer-based cartridge casing comprising: an
upper polymer component, molded from a polymer, comprising: 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, a volume
inside the wall at least partially forming a propellant chamber;
and an overlap portion extending from the wall near the second end;
an 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 insert; a rim and groove disposed around an outside of the
insert approximate the second end; a primer pocket disposed inside
the second end; and a flash hole, inside the insert and
communicating between the primer pocket and upper polymer
component; and a flash tube in fluid communication with the primer
pocket and the propellant chamber.
3. The high strength polymer-based cartridge casing of claim 2,
wherein the flash tube comprises: a front end disposed in the
propellant chamber; a back end disposed in the primer pocket
comprising a washer end sized larger than the flash hole and
preventing the back end from passing through the flash hole.
4. The high strength polymer-based cartridge casing of claim 3,
wherein the back end of the flash tube is sized approximately to a
diameter of the primer pocket.
5. The high strength polymer-based cartridge casing of claim 2,
wherein the flash tube comprises: a vent hole disposed on a
perimeter of the flash tube.
6. The high strength polymer-based cartridge casing of claim 2,
wherein the flash tube extends approximately 50% to 90% of a length
of the propellant chamber.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 62/319,609 filed Apr. 7, 2016.
[0002] This application claims priority to and is a
Continuation-in-Part of U.S. patent application Ser. No. 15/043,026
filed Feb. 12, 2016 which is a Continuation of U.S. patent
application Ser. No. 14/531,124 filed Nov. 3, 2014, now U.S. Pat.
No. 9,261,335 issued Jan. 27, 2016, which claims priority to
Divisional of U.S. patent application Ser. No. 13/865,040 filed
Apr. 17, 2013, now U.S. Pat. No. 8,875,633 issued Nov. 4, 2014,
which claims priority to U.S. patent application Ser. No.
13/350,607 filed Jan. 13, 2012, now U.S. Pat. No. 8,443,730 issued
May 21, 2013, which claims priority to U.S. Provisional Application
No. 61/433,170 filed Jan. 14, 2011, U.S. Provisional Application
No. 61/509,337 filed Jul. 19, 2011, U.S. Provisional Application
No. 61/532,044 filed Sep. 7, 2011, and U.S. Provisional Application
No. 61/555,684 filed Nov. 4, 2011.
[0003] This application also claims priority to and is a
Continuation-in-Part of U.S. patent application Ser. No. 15/187,421
filed Jun. 20, 2016 which is a Continuation of U.S. patent
application Ser. No. 14/642,922 filed Mar. 10, 2015, now U.S. Pat.
No. 9,372,054 issued Jun. 21, 2016, which is a Continuation of U.S.
patent application Ser. No. 14/315,564 filed Jun. 26, 2014, now
U.S. Pat. No. 9,003,973 issued Apr. 14, 2015, which is Divisional
of U.S. patent application Ser. No. 13/549,351 filed Jul. 13, 2012,
now U.S. Pat. No. 8,763,535 issued Jul. 1, 2014, which is
Continuation-in-Part of U.S. patent application Ser. No.
13/350,585, filed Jan. 13, 2012, abandoned, which claims priority
to U.S. Provisional Application No. 61/433,170 filed Jan. 14,
2011.
[0004] This application is a Continuation-in-Part of U.S. patent
application Ser. No. 15/463,906 filed Mar. 20, 2017, which is a
Continuation of U.S. patent application Ser. No. 14/482,843 filed
Sep. 10, 2014, now U.S. Pat. No. 9,599,443 issued Mar. 21, 2017,
which in turn is a Continuation of U.S. patent application Ser. No.
14/041,709 filed Sep. 30, 2013, abandoned, which in turn is a
continuation of U.S. patent application Ser. No. 12/847,319 filed
Jul. 30, 2010, now U.S. Pat. No. 8,573,126 issued Nov. 5, 2013.
[0005] This application is a Continuation-in-Part of U.S. patent
application Ser. No. 15/463,906 filed Mar. 20, 2017, which is a
Continuation of U.S. patent application Ser. No. 14/482,843 filed
Sep. 10, 2014, now U.S. Pat. No. 9,599,443 issued Mar. 21, 2017,
which is a continuation of U.S. patent application Ser. No.
14/460,877 filed Aug. 15, 2014, now U.S. Pat. No. 9,194,680 issued
Nov. 24, 2015, which in turn is a Divisional of U.S. patent
application Ser. No. 13/836,192 filed Mar. 15, 2013, now U.S. Pat.
No. 8,807,008 issued Aug. 19, 2014, which in turn is a
Continuation-in-Part of U.S. patent application Ser. No. 13/350,607
filed Jan. 13, 2012, now U.S. Pat. No. 8,443,730 issued May 21,
2013, which claims priority to U.S. Provisional Application No.
61/433,170 filed Jan. 14, 2011, U.S. Provisional Application No.
61/509,337 filed Jul. 19, 2011, U.S. Provisional Application No.
61/532,044 filed Sep. 7, 2011, and U.S. Provisional Application No.
61/555,684 filed Nov. 4, 2011.
[0006] All of the above applications are incorporated herein by
reference.
FIELD OF INVENTION
[0007] The present subject matter relates to ammunition articles
with plastic components such as cartridge casing bodies, and, more
particularly, a two-piece insert used with the plastic
cartridges.
BACKGROUND
[0008] It is well known in the industry to manufacture projectiles
and corresponding cartridge cases from either brass or steel.
Typically, industry design calls for materials that are strong
enough to withstand extreme operating pressures and which can be
formed into a cartridge case to hold the projectile, while
simultaneously resist rupturing during the firing process.
[0009] Conventional ammunition typically includes four basic
components, that is, the projectile, the cartridge case holding the
projectile therein, a propellant used to push the projectile down
the barrel at predetermined velocities, and a primer, which
provides the spark needed to ignite the propellant which sets the
projectile in motion down the barrel.
[0010] The cartridge case is typically formed from brass and is
configured to hold the projectile therein to create a predetermined
resistance, which is known in the industry as bullet pull. The
cartridge case is also designed to contain the propellant media as
well as the primer. However, brass is heavy, expensive, and
potentially hazardous. For example, the weight of .50 caliber
ammunition is about 60 pounds per box (200 cartridges plus
links).
[0011] The cartridge case, which is typically metallic, acts as a
payload delivery vessel and can have several body shapes and head
configurations, depending on the caliber of the ammunition. Despite
the different body shapes and head configurations, all cartridge
cases have a feature used to guide the cartridge case, with a
projectile held therein, into the chamber of the gun or
firearm.
[0012] The primary objective of the cartridge case is to hold the
projectile, primer, and propellant therein until the gun is fired.
Upon firing of the gun, the cartridge case seals the chamber to
prevent the hot gases from escaping the chamber in a rearward
direction and harming the shooter. The empty cartridge case is
extracted manually or with the assistance of gas or recoil from the
chamber once the gun is fired.
[0013] One of the difficulties with polymer ammunition is having
enough strength to withstand the pressures of the gases generated
during firing. In some instances, the polymer may have the
requisite strength, but be too brittle at cold temperatures, and/or
too soft at very hot temperatures. Additionally, the spent
cartridge is extracted at its base, and that portion must withstand
the extraction forces generated from everything from a bolt action
rifle to a machine gun.
[0014] A number of U.S. patents and applications by Padgett, see
above, disclose a single metal insert with a one or two piece
polymer cartridge case. The two-piece case facilitates the
manufacturing of a bottleneck cartridge. Molding a polymer
cartridge requires a "pin" to be inserted into a mold to form the
polymer and then extracted. The wider diameter of the powder
chamber of a standard bottleneck cartridge opposed to the diameter
of the mouth makes it impossible to remove the molding pin. The
two-piece design allows a pin to be inserted through the wider
bottom to the narrower neck. The second piece of the cartridge can
overmold the metal insert for maximum strength and the two polymer
sections can be fused together. For a blank or subsonic polymer
cartridge, the walls can be made straight from the mouth which
eliminates the need for an internal diameter change.
[0015] Hence a need exists for a polymer casing that can perform as
well as or better than the brass alternative. A further improvement
is the base inserts to the polymer casings that are capable of
withstanding all of the stresses and pressures associated with the
loading, firing and extraction of the casing, while reducing
manufacturing costs and maintaining strength.
[0016] Turning now to the concept of flash tubes, it is not new and
is currently used in many large caliber weapon systems. The flash
tube is essentially a tube that runs through the center of the
cartridge from the primer pocket to the middle area of the case
with the goal of enhancing the ignition of the propellant
charge.
[0017] In large caliber weapons, the flash tube is often filled
with an extremely fast burning propellant such as black powder.
These flash tubes often have vents in multiple locations along the
axis of the tube to ignite the powder in the cartridge at the same
time resulting in better ignition.
[0018] In small caliber ammunition, the propellant volume is not
significant enough to warrant the need for such a device. That
said, research conducted during World War II and again in the
1970's using a flash tube vented only at the top showed that the
ignition of the propellant in a 50 BMG case could be significantly
improved.
[0019] During the 1930's, small arms expert Elmer Keith proposed
that the use of a flash tube in small caliber ammunition could
result in better performance. The concept can be reduced to this:
igniting the powder column near the top of the cartridge would
result in the powder burning top down thus keeping the propellant
in the case instead of propelling it down the bore. By keeping the
powder in the case until fully consumed, the heat of combustion
would be better localized enhancing the burn and reducing the heat
generated in the bore. This has the added benefit of reducing
barrel erosion caused by the "sand blasting effect" of the powder
granules being propelled down the bore. Using this pioneering
technique, Mr. Keith was able to maintain the same velocity as the
standard cartridge, yet peak chamber pressure was reduced by close
to 10,000 PSI. He termed this method as Duplex Loading. This should
not be confused with current use of the term which describes the
use of one or more powders of varying burn rate stacked in a
case.
[0020] The use of the flash tube is now better known as front or
forward priming. Mr. Keith continued his testing and showed because
the pressure had been reduced, he could increase the charge to get
back to "normal" pressures resulting in substantial velocity
increases.
[0021] During WWII, Mr Keith was called to Frankford Arsenal to
work on the .50 caliber cartridge using his forward priming
technique. Using this technique, Mr Keith was able to produce
documented increases in velocity of 200 fps. Unfortunately due to
the conflict at hand, the research was concluded as the army deemed
that changes to an already extremely effective cartridge would be
inadvisable at a time when maximum production was the primary goal.
The work on the forward primed .50 caliber cartridge was
essentially dropped and never really picked up again by the
army.
[0022] Mr Keith continued his work on small caliber ammunition,
employing his forward priming technique on the 30-06 cartridge and
eventually forming a small ammunition company. Though the results
of his efforts showed great promise, manufacturing processes kept
the technique from the larger market.
[0023] Later in the 1970's, Richard Culver picked up where Mr.
Keith left off and began testing forward priming as well as duplex
and triplex loading. I will not cover the research associated with
duplex and triplex loading due to the fact that the results can
have disastrous effects, but Mr. Culver's testing of the forward
priming confirmed Mr Keith's earlier work conclusively.
[0024] Culver used the 30-06 and 7.62 NATO cartridges for his
study. He produced cases using a flash tube very similar to what Mr
Keith described. Culver created a very detailed experimental study
to test the effects of a flash tube in small caliber ammunition.
His work was based on the concepts that Mr Keith has postulated,
that the forward priming had two significant benefits. The first is
directing the primer blast toward the base of the projectile and
the second being the ignition of the top of the powder charge
first. The initial primer blast propels the projectile into the
bore, sealing it, before the charge is ignited thus increasing the
volume prior to ignition. This has the effect of reducing the peak
pressure. In conventionally loaded ammunition, the charge is
ignited from the rear forward resulting in much of the charge
burning prior to any movement of the projectile.
[0025] The results of Mr Culver's experiments confirmed that
forward priming of a 7.62 cartridge significantly reduced the peak
pressures for a given load. He furthered the testing to increase
the pressure back to normal by increasing the load and was able to
gain an additional 100 fps while maintaining normal pressures.
[0026] Mr Culver proposed that these benefits could be extremely
beneficial in machine gun use where the reduced barrel temperatures
could allow for longer strings of firing without damaging the
barrel. The reduced erosion could also increase barrel life. In his
closing, he recommended that the 300 Win Mag cartridge was an ideal
cartridge for further studying this technique due to is volume to
bore diameter ratio. Some examples of forward primed brass
cartridges are illustrated in FIGS. 21A and 21B.
SUMMARY
[0027] The examples of the present invention for 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.
[0028] Another example of a high strength polymer-based cartridge
casing has an upper polymer component, molded from a polymer, with
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, a
volume inside the wall at least partially forming a propellant
chamber, and an overlap portion extending from the wall near the
second end. Then an upper insert has a first end and an opposing
second end with 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 is
disposed approximate to the second end. A lower insert has a front
end and a back end with 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
back end, and a flash hole, inside the lower insert and
communicating between the primer pocket and upper polymer
component. Additionally included is a flash tube in fluid
communication with the primer pocket and the propellant
chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] 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.
[0030] 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.
[0031] FIG. 1 is a cross-section of a bottle neck cartridge with a
two-piece insert of the present invention;
[0032] FIG. 2 illustrates a side view of an example of the upper
component;
[0033] FIG. 3 is a magnified cross-section illustrating an example
of the upper component and upper insert of the present
invention;
[0034] FIG. 4 is a magnified cross-section illustrating an example
of the upper component, upper insert, and lower insert of the
present invention;
[0035] FIG. 5 is a cross-section illustrating an example of the
upper insert of the present invention;
[0036] FIG. 6 is a side view of an example of a lower insert;
[0037] FIG. 7 is a bottom front perspective view of the lower
insert of FIG. 6;
[0038] FIG. 8 is a longitudinal cross-section view of the lower
insert of FIG. 6;
[0039] FIG. 9A is a longitudinal cross-section view of example of
belted lower insert;
[0040] FIG. 9B is a cross-section view of another example of a
basin lower insert installed;
[0041] FIG. 10 is a cross-section view of another example of the
upper component, upper insert and lower insert engaged;
[0042] FIGS. 11A and 11B are side and side-back profile views,
respectively, of another example of an upper insert;
[0043] FIGS. 12A and 12B are side and side-back profile views,
respectively, of another example of a lower insert;
[0044] FIG. 13 is a cross-section of another example of a lower
insert;
[0045] FIG. 14 is a cross-section of a example of a crimped lower
insert;
[0046] FIG. 15 is a cross-section of yet another example of an
upper insert;
[0047] FIG. 16 is a cross-section view of an example of the upper
and lower inserts engaged;
[0048] FIG. 17 is an exploded view of the entire cartridge;
[0049] FIG. 18 is a cross-section view of an example of a flash
tube;
[0050] FIGS. 19A through 19E each illustrate different examples of
flash tubes;
[0051] FIG. 20 is an exploded view of an example of the entire
cartridge, including a flashtube; and
[0052] FIGS. 21A and 21B are prior art flash tube structures for
brass cartridges.
DETAILED DESCRIPTION
[0053] 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.
[0054] 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.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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.
[0062] 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).
[0063] 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 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).
[0064] 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.
[0065] 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.
[0066] 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.apprxeq.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.
[0067] 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.apprxeq.Ti.apprxeq.(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.
[0068] 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.
[0069] 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.
[0070] 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).
[0071] 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.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] 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.
[0079] 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.
[0080] 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.
[0081] 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.
[0082] 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.
[0083] 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.
[0084] 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.
[0085] 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.
[0086] 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 2/3 or 3/4 (.about.66% and .about.75%) of
the distance to the shoulder 204 or bottom of the projectile.
[0087] 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.
[0088] 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.
[0089] 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.
[0090] 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.
[0091] 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.
[0092] 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.
* * * * *