U.S. patent application number 10/580577 was filed with the patent office on 2007-11-29 for low energy training cartridge.
This patent application is currently assigned to UTM IP LIMITED. Invention is credited to Michael Ernest Saxby.
Application Number | 20070272111 10/580577 |
Document ID | / |
Family ID | 29797851 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070272111 |
Kind Code |
A1 |
Saxby; Michael Ernest |
November 29, 2007 |
Low Energy Training Cartridge
Abstract
A low energy cartridge comprising: an outer casing 4; a rear
telecospically slidable portion 1 disposed, in use, to be
telescopically extendable with respect to the outer casing 4 in a
direction towards the breech-block of a firearm; a front
telescopically slidable portion 6 disposed, in use, to be
telescopically extendable with respect to the outer casing 4 in a
direction towards the barrel X of a firearm; means 2, 3 for causing
each telescopically slidable portion 1, 6 to telescopically extend
in reaction to firing of a firearm containing the cartridge; an
open end 13 of the front portion 6 configured to receive a
projectile 7 and means for propelling a projectile 7 from the open
end 13.
Inventors: |
Saxby; Michael Ernest;
(Bexhill-on-Sea, GB) |
Correspondence
Address: |
LAHIVE & COCKFIELD, LLP
ONE POST OFFICE SQUARE
BOSTON
MA
02109-2127
US
|
Assignee: |
UTM IP LIMITED
MILDENHALL
GB
|
Family ID: |
29797851 |
Appl. No.: |
10/580577 |
Filed: |
November 26, 2004 |
PCT Filed: |
November 26, 2004 |
PCT NO: |
PCT/GB04/04994 |
371 Date: |
April 26, 2007 |
Current U.S.
Class: |
102/444 |
Current CPC
Class: |
F42B 5/02 20130101; F42B
5/307 20130101 |
Class at
Publication: |
102/444 |
International
Class: |
F42B 8/00 20060101
F42B008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2003 |
GB |
0327492.5 |
Claims
1. A low energy cartridges comprising: an outer casing; a rear
telescopically slidable portion disposed, in use, to be
telescopically extendable with respect to the outer casing in a
direction towards a breech-block of a firearm; a front
telescopically slidable portion disposed, in use, to be
telescopically extendable with respect to the outer casing in a
direction towards a barrel of the firearm; means for causing each
telescopically slidable portion, in use, to telescopically extend
in reaction to firing of the firearm containing the cartridge; an
open end of the front telescopically slidable portion configured to
receive a projectile; and means for propelling the projectile from
the open end.
2. A low energy cartridge as claimed in claim 1 wherein the front
telescopically extendable portion is made from a plastic, other
pliable material or of a composite construction so as to seal the
front portion into the outer casing and a chamber of the
firearm.
3. A low energy cartridge as claimed in claim 1 further comprising
a projectile received in the front telescopically slidable portion,
the projectile comprising a bullet configured such that the bullet
remains sealed in the front portion until a portion of the bullet
has entered a rifled part of the barrel of the firearm.
4. A low energy cartridge as claimed in claim 1, wherein the means
for causing the telescopically slidable portions to telescopically
extend comprises a gas releasing device positioned at a rear of the
rear telescopically slidable portion, an open ended gas passage
extending through the rear portion and forwardly of the gas
releasing devices and a closure member sealingly slidably located
in the gas passage.
5. A low energy cartridge as claimed in claim 1 wherein the means
for causing the telescopically slidable portions to telescopically
extend comprises a primer positioned at a rear of the rear portion,
and an open ended gas passage extending through the rear portion
and forwardly of the primer.
6. A low energy cartridge as claimed in claim 5 further comprising
a propellant charge ignited by the primer and positioned between
the front and rear telescopically slidable portions.
7. A low energy cartridge as claimed in claim 4 further comprising
a primer positioned at a rear of the front portion and an open
ended gas passage extending through the front portion and forwardly
of the primer, the open ended gas passage being closable by a
projectile.
8. A low energy cartridge as claimed in claim 7 wherein the primer
of the front portion is initiated on impact of the closure member
with the primer.
9. A low energy cartridge as claimed in claim 1 wherein the outer
casing is shaped so as to include at or near each end an inwardly
jutting surface which serves to stop the telescopically slidable
portions separating from the outer casing when the portions
extend.
10. A low energy cartridge as claimed in claim 9 wherein the
inwardly jutting surface comprises an annular flange having an
inner radius which is slightly smaller than a largest radius of the
corresponding telescopically slidable portion.
11. A low energy cartridge as claimed in claim 4 wherein the
closure member comprises a plug which has a cross section in a
direction perpendicular to a direction of travel of the
telescopically slidable portions, of similar shape and size to that
of the gas passage of the first telescopically slidable
portion.
12. A low energy cartridge as claimed in claim 11 wherein the
closure member is substantially spherical.
13. A low energy cartridge as claimed in claim 12 wherein the
closure member is a ball.
14. A low energy cartridge as claimed in claim 13 wherein the ball
is made from steel.
15. A low energy cartridge as claimed in claim 13 wherein the ball
is made from a plastic material.
16. A low energy cartridge as claimed in claim 4 wherein the
closure member has an outer surface which is selected to be of a
low friction material so as to allow the member to easily slide
along the gas passage.
17. A low energy cartridge as claimed in claim 1 further comprising
at least one gas tight seal between a telescopically slidable
portion and the outer casing.
18. (canceled)
Description
TECHNICAL FIELD
[0001] The present invention relates to ammunition, particularly
non-lethal ammunition intended for use in training and war games.
The invention has particular application in cartridges in which a
rearwards movement of a portion of the cartridge is used to
initiate the recycling of an automatic or semi-automatic
firearm.
BACKGROUND ART
[0002] Low energy cartridges for cycling self loading guns are
widely known. For example U.S. Pat. No. 5,677,505, U.S. Pat. No.
6,095,051, U.S. Pat. No. 5,700,972 and U.S. Pat. No. 6,439,123 B1
all relate to a two part cartridge which has a casing slidable
relative to a plug at the forward end of the cartridge. When the
cartridge is loaded in a gun and fired, force provided by a
propellant gas is employed to urge the slidable casing back against
the breech-block and recycle the weapon.
[0003] An example of such a cartridge is illustrated in FIG. 1 of
the accompanying drawings. A problem that arises with these prior
art cartridges is that they perform inconsistently when used in
guns of the same calibre but made by different manufacturers. This
is due to design variations between guns of different
manufacturers, variations which the manufactures claim, when used
in conjunction with live ammunition, provide certain technical
advantages. These variations, discussed in more detail in the
description of FIG. 1 given below, can result in different degrees
of gas loss and volume related pressure variations around the
bullet.
[0004] The high energy associated with propulsion of live
ammunition copes with these differences, however, the much smaller
amount of energy available to propel a bullet using prior art, low
energy training ammunition cartridges does not cope well.
Consequently, varying propellant gas loss and pressure variations
associated with comparable weapons from different manufacturers
significantly affects performance when these guns are used with low
energy cartridges to an extent that, behaviour of the ammunition
when fired from a weapon becomes inconsistent and unpredictable.
The changes encountered in the ammunition performance from one gun
type/make to another are considered unacceptable.
[0005] The present invention aims to provide a novel low energy
cartridge which allows more consistent and predictable performance
when firing non-lethal ammunition from weapons of the same calibre,
but different manufacturer.
SUMMARY OF INVENTION
[0006] In accordance with the present invention there is provided a
low energy cartridge comprising:
[0007] an outer casing;
[0008] a rear telescopically slidable portion disposed, in use, to
be telescopically extendable with respect to the outer casing in a
direction towards the breech-block of a firearm;
[0009] a front telescopically slidable portion disposed, in use, to
be telescopically extendable with respect to the outer casing in a
direction towards the barrel of a firearm;
[0010] means for causing each telescopically slidable portion, in
use, too telescopically extend in reaction to firing of a firearm
containing the cartridge;
[0011] an open end of the front portion configured to receive a
projectile and
[0012] means for propelling a projectile from the open end.
[0013] Optionally the cartridge further includes a projectile
received in the front portion of the cartridge, the projectile
comprising a bullet which is configured such that, in use, the
bullet remains sealed in the front portion of the cartridge until a
portion of it has entered the rifled part of the barrel of the
firearm.
[0014] Preferably, the means for causing the telescopically
slidable portions to telescopically extend include a gas releasing
device positioned to the rear of the rear telescopically slidable
portion, an open ended gas passage extending through the portion
and forwardly of the gas releasing device and a closure member
sealingly slidably located in the gas passage. The gas releasing
device may be a primer.
[0015] Conveniently, the means for causing the portions to
telescopically slide comprise a primer positioned towards the rear
of each of the front and rear telescopically slidable portions.
Optionally, the means may comprise a primer positioned to the rear
of the rear portion which in turn ignites a propellant charge
causing both portions to telescopically slide. The propellant
charge may also, optionally, propel a projectile seated in the gas
passage of the front portion. Where a primer is present in the
front portion, this primer may be initiated by percussion, for
example on impact by the aforementioned closure member or, by
chemical action of a component of gas released in the gas passage
of the rear portion.
[0016] In use of a typical embodiment, the cartridge is loaded in
the firearm with both telescopically slidable portions retracted
into the outer casing. A projectile is positioned in the open end
of the gas passage of the front portion. When the firearm is fired,
the firing pin strikes the primer causing release of gas into the
gas passage extending forwardly of the primer. As the gas expands,
the closure member is caused to slide along the gas passage at
increasing speed towards the primer of the second telescopically
slidable portion. At the same time, the expanding gas forces the
rear telescopically slidable portion to extend towards the breach
block of the firearm, travelling in an opposing direction to the
closure member. As the closure member exits the open end of the
extending rear portion, gas escapes the passage of the rear portion
and expands into a space to the rear of the front portion. This
causes the telescopically slidable front portion to extend towards
the barrel of the firearm. Thus, the two telescopically slidable
portions are caused to travel in opposing directions.
[0017] The accelerating closure member strikes the primer of the
front portion causing release of a second quantity of gas into the
gas passage extending forwardly of this second primer. As it
expands, this second quantity of gas forces the projectile out of
the open ended gas passage and into the barrel of the firearm.
[0018] It will be appreciated that the front telescopically
slidable portion extends before the bullet is propelled through the
barrel of the firearm. The portion thus creates a seal between the
cartridge and the barrel to enable all of the propellant gas,
without pressure drops or gas losses, to propel the bullet up the
barrel. This overcomes inconsistencies in performance of cartridges
in firearms of varying manufacturer's designs.
[0019] Desirably, the outer casing is shaped so as to include at or
near each end an inwardly jutting surface which serves to stop the
telescopically slidable portions separating from the outer casing
when they extend. Optionally, the inwardly jutting surface
comprises an annular flange having an inner radius which is
slightly smaller than the largest radius of the corresponding,
telescopically slidable portion.
[0020] The closure member is conveniently a plug which has a cross
section in a direction perpendicular to the direction of travel of
the telescopically slidable portions, of similar shape and size to
that of the gas passage of the first telescopically slidable
portion. Desirably, the closure member is substantially spherical.
The closure member may, optionally, comprise a steel ball.
Alternatively, the closure member may comprise a ball of plastic
material. The outer surface of the closure member is desirably
selected to be of a low friction material so as to allow the member
to easily slide along the gas passage when the first gas is
released.
[0021] Desirably a gas tight seal is provided between at least the
rear telescopically slidable portion and the outer casing and
optionally also the front telescopically slidable portion and the
outer casing.
[0022] Either or both of the primers may in turn ignite a
propellant charge.
BRIEF DESCRIPTION OF DRAWINGS
[0023] For the purposes of exemplification, an embodiment of the
invention will now be further described with reference to the
following Figures in which;
[0024] FIG. 1 shows schematically a typical cartridge as is known
from the prior art, correctly located in the chamber of a
firearm.
[0025] FIG. 2 shows in cross section an embodiment of a
telescopically expandable cartridge in accordance with the
invention located in the chamber of a firearm, prior to firing;
[0026] FIG. 3 shows the embodiment of FIG. 2 shortly after the
firearm has been fired but before the projectile is propelled into
the barrel of the firearm;
[0027] FIG. 4 shows the embodiment of FIG. 3 at a later moment when
the projectile has been propelled into the barrel of the
firearm.
DESCRIPTION OF ILLUSTRATED EMBODIMENT
[0028] FIG. 1 illustrates schematically a typical cartridge Z as is
known from the prior art. In the figure, dimension A is a constant
used by all firearm manufacturers for a given ammunition type. The
cone shaped surface B is not common to all manufacturers designs
and may be plane and smooth. Also, in some manufacturers firearms,
the cartridge may make a seal between the rifled barrel X and the
chamber Y or it may have grooves that run from the surface with
dimension C across the cone shaped face and along the surface with
dimension A thereby rendering it impossible to make a seal between
the rifled barrel X and the chamber Y.
[0029] The dimensions C and D may vary from manufacturer to
manufacturer as may diameters E and F. H represents the direction
of extension of a telescopically expanding low energy cartridge
during recycling.
[0030] The dimension I may vary from manufacturer to manufacturer.
In addition, manufacturers use slightly varying breech and chamber
dimensions and configurations (for example fluted chambers) for use
with live ammunition.
[0031] The variations in the previously discussed design parameters
of firearms of the same calibre but different manufacturer cause
gas loss and volume related pressure variations around a bullet
propelled from the firearm.
[0032] FIG. 2 illustrates a cartridge in accordance with the
invention. As can be seen from the Figure, the cartridge of the
invention comprises an outer casing 4 in to which are
telescopically slidably arranged a rear portion 1 and front portion
6. The rear portion includes a primer 2 sited to the rear of the
portion where, in use, it can be initiated in striking by a firing
pin of the firearm (not shown). At the opposing end of the rear
portion 1, on the outer surface of the portion 1 is an annular
flange 9 which includes an annular recess which receives a sealing
ring 10. The sealing ring 10 provides a gas tight seal which
prevents gases released from the primer 2 escaping from the rear of
the cartridge. Towards the rear of the outer casing 4 on an inner
surface of the casing as an annular protrusion 8. the inner radius
of the annular protrusion is selected to be smaller than the outer
radius of the flange 9 such that, when the rear portion 1 extends,
it is prevented from separating from the casing by flange 9
abutting against protrusion 8.
[0033] A gas passage 11 extends forwardly of the primer 2 in the
rear portion 1. Carried within the gas passage 11 is a closure
member which may be a steel or plastic ball 3 which has a diameter
comparable to that of the diameter of the gas passage 11. The ball
3 acts as a closure member preventing the escape of gas released by
the primer 2 from escaping through the open end of the gas passage
11. The ball 3 is, however, slidable within the gas passage 11.
[0034] The front portion 6 is made from plastic or composite
construction of pliable material which serves to seal in the outer
casing 4. The pliable nature of the material allows deformation at
the interface between the front portion 6 and the entry to the
barrel X maintaining a seal even if fluting is present. The front
portion further comprises a second primer 5 sited towards its rear
end. A second gas passage 12 extends forwardly of the second primer
5 and opens into a socket 13 configured to receive an end of a
bullet or other projectile 7.
[0035] As for the rear portion, the smallest diameter (at position
14) of the front end of the casing 4 is smaller than the largest
diameter (at position 15) of the front portion 6 so as to prevent
separation of the front portion 6 from the casing 4 when the front
portion telescopically extends.
[0036] In a desirable application of an embodiment of the
invention, a bullet 7 is configured such that the bullet 7 remains
sealed in the socket 13 of the pliable front portion 6 of the
cartridge until the it has entered the rifled part X of the barrel
of the firearm. This may be achieved by providing a bullet 7 with a
parallel section 7a, sealed in the socket 13 of the pliable front
portion 6.
[0037] FIG. 3 shows the initial action of the cartridge of FIG. 2
when the firearm is fired. On firing, a firing pin P strikes the
primer 2 in of the rear portion 1 which causes gas to be released
into gas passage 11. The pressure of the gas in passage 11 causes
ball 3 to travel towards the front portion 6. As the ball begins to
exit the gas passage 11, gas escapes past the ball and begins to
force the front 6 and rear 1 portions apart. The rear portion 1
extends telescopically towards the breech of the firearm so as to
recycle the firearm as is known from the prior art.
[0038] As can be seen from FIG. 4, the front portion 6 also
telescopically extends so as to seal the front pliable portion at
the interface between the guns chamber Y and the barrel X and
deposit the front end of the projectile 7 into the barrel X of the
firearm. The ball 3 strikes the primer 5 of the front portion 6
causing release of gas into gas passage 12. The released gas builds
up a pressure behind projectile 7 which ultimately forces the
projectile along the barrel X.
* * * * *