U.S. patent application number 15/228799 was filed with the patent office on 2016-11-24 for selectable kinetic energy of projectiles.
The applicant listed for this patent is Defendtex Pty. Ltd.. Invention is credited to James Michael O'Dwyer, Sean Patrick O'Dwyer.
Application Number | 20160341508 15/228799 |
Document ID | / |
Family ID | 32853872 |
Filed Date | 2016-11-24 |
United States Patent
Application |
20160341508 |
Kind Code |
A1 |
O'Dwyer; James Michael ; et
al. |
November 24, 2016 |
SELECTABLE KINETIC ENERGY OF PROJECTILES
Abstract
Projectiles with sealed propellant are described herein. In one
embodiment of the invention, a projectile includes a body having a
nose portion and a tail portion, a plurality of propellant charges
contained within the body, a plurality of selectable initiators
contained within the body for ignition of respective propellant
charges, one or more ports for exit of ignition gases produced by
the charges for propulsion of the projectile from the weapon, and
one or more inductors for inducing a firing current, where at least
one initiator only initiates on receiving a firing current which is
different from the firing signal required to initiate the other
initiators.
Inventors: |
O'Dwyer; James Michael;
(Brisbane, AU) ; O'Dwyer; Sean Patrick; (Norman
Park, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Defendtex Pty. Ltd. |
Moorabbin VIC |
|
AU |
|
|
Family ID: |
32853872 |
Appl. No.: |
15/228799 |
Filed: |
August 4, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13846484 |
Mar 18, 2013 |
9448026 |
|
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15228799 |
|
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|
12346600 |
Dec 30, 2008 |
8402897 |
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13846484 |
|
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|
10545206 |
Jun 16, 2006 |
7475636 |
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PCT/AU2004/000141 |
Feb 10, 2004 |
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12346600 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41A 19/62 20130101;
F42B 5/02 20130101; F42B 5/10 20130101; F42B 5/08 20130101; F41A
19/65 20130101; F42B 5/035 20130101; F41A 19/61 20130101; F41A
19/58 20130101 |
International
Class: |
F41A 19/58 20060101
F41A019/58; F42B 5/08 20060101 F42B005/08; F42B 5/03 20060101
F42B005/03; F41A 19/61 20060101 F41A019/61 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 10, 2003 |
AU |
2003900572 |
May 2, 2003 |
AU |
2003902103 |
May 23, 2003 |
AU |
2003902556 |
Claims
1. A barrel assembly, comprising a barrel containing a stack of
projectiles arranged axially from nose to tail of, each projectile
including a body having a nose portion and a tail portion, a
plurality of propellant charges contained within the body, a
plurality of selectable initiators contained within the body for
ignition of respective propellant charges, one or more ports for
exit of ignition gases produced by the charges for propulsion of
the projectile from the weapon, and one or more inductors for
inducing a firing current, wherein at least one initiator only
initiates on receiving a firing current which is different from the
firing signal required to initiate the other initiators.
2. A barrel assembly as in claim 1, wherein the firing currents
differ by energy level.
3. A method of firing projectiles from a barrel, comprising:
loading the barrel with a stack of projectiles arranged axially
nose to tail; sequentially selecting the leading projectile in the
stack for firing; determining a required kinetic energy or muzzle
velocity of the leading projectile; selecting one or a combination
of inductively initiated propellant charges within the leading
projectile to achieve the required energy or velocity; selecting a
firing signal or signals required to initiate the selected
propellant charges; and inductively triggering the selected
propellant charges.
4. A method according to claim 3, further comprising: determining a
required kinetic energy or muzzle velocity of the last projectile;
selecting one or a combination of propellant charges within the
barrel to achieve the required energy or velocity; selecting a
firing signal or signals required to initiate the selected
propellant charges; and triggering the selected propellant
charges.
5. A method according to claim 4, further comprising triggering any
remaining propellant charges in the barrel once the last projectile
has been fired.
Description
[0001] This is a divisional application of U.S. Ser. No.
13/846,484, filed Mar. 18, 2013, which is a continuation of U.S.
patent application Ser. No. 12/346,600, filed Dec. 30, 2008, now
U.S. Pat. No. 8,402,897, issued Mar. 26, 2013, which is a
divisional application of U.S. patent application Ser. No.
10/545,206, filed Jun. 16, 2006, now U.S. Pat. No. 7,475,636,
issued Jan. 13, 2009, which is a national phase application of
International Application No. PCT/AU2004/000141, filed Feb. 10,
2004, which claims the priority from Australian Patent Application
Nos.: 2003900572 filed Feb. 10, 2003; 2003902103 filed May 2, 2003;
and 2003902556 filed May 23, 2003. The disclosures of the
above-identified applications are incorporated by reference herein
in their entirety.
FIELD
[0002] The present invention relates generally to projectiles. More
particularly, this invention relates to projectiles with sealed
propellant.
BACKGROUND
[0003] The kinetic energy (KE) of conventional projectiles, for
example standard mortar rounds, may be varied by tailoring the
amount of propellant that is associated with each projectile before
firing. This may require different internal propellant loads
produced during manufacture or the use of auxiliary propellant
charges, where possible.
[0004] In mortar rounds, the projectiles and auxiliary propellant
charges are generally separate from one another before firing. The
auxiliary propellant is typically provided in a number of small
parcels that may be supplied in different volumes or in the same
volume for incremental use. Depending on the range that is
required, the mortar operator manually attaches one or more parcels
providing the appropriate amount of propellant to the mortar round
before insertion into a tube or barrel for firing. This procedure
also considerably slows the rate of fire that can be achieved by
the weapon and is prone to human error when loading.
[0005] It will be appreciated that a more cost effective,
convenient and reliable arrangement for varying the kinetic energy
of projectiles is desirable, particularly where a high rate of fire
is required. Particularly where the projectile firing weapon is of
the type including a plurality of rounds stacked in a barrel for
sequential firing and required to be remotely controlled. It would
be of further advantage if the construction of individual rounds
was substantially homogeneous.
SUMMARY
[0006] Projectiles with sealed propellant are described herein. In
one embodiment of the invention, a projectile includes a body
having a nose portion and a tail portion, a plurality of propellant
charges contained within the body, a plurality of selectable
initiators contained within the body for ignition of respective
propellant charges, one or more ports for exit of ignition gases
produced by the charges for propulsion of the projectile from the
weapon, and one or more inductors for inducing a firing current,
where at least one initiator only initiates on receiving a firing
current which is different from the firing signal required to
initiate the other initiators.
[0007] Other features of the present invention will be apparent
from the accompanying drawings and from the detailed description
which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] In order that this invention may be more readily understood
and put into practical effect, reference will now be made to the
accompanying drawings which illustrate embodiments of the
invention, wherein:
[0009] FIGS. 1A-1F show a first embodiment in which a projectile
has forward ports for exit of propellant gases;
[0010] FIGS. 2A-2D show a second embodiment in which a projectile
has rearward ports for exit of propellant gases;
[0011] FIGS. 3A, 3B show an inductive firing system for the
projectiles;
[0012] FIG. 4 is a sectional side elevational view of a projectile
of another embodiment of the invention, prior to firing;
[0013] FIG. 5 is a sectional side elevational view of the
projectile of the embodiment, after firing the third and fourth
propellant charges;
[0014] FIG. 6 is a sectional side elevational view of the
projectile of the embodiment, after firing the second, third and
fourth propellant charges;
[0015] FIG. 7 is a sectional side elevational view of the
projectile of the embodiment, after firing all propellant
charges;
[0016] FIG. 8 is a sectional end elevational view of the projectile
of the embodiment;
[0017] FIG. 9 is a sectional side elevational view of a variation
to the projectile of the embodiment;
[0018] FIG. 10 is a sectional side elevational view of a projectile
of another embodiment of the present invention, prior to
firing;
[0019] FIG. 11 is a sectional end elevational view of the
projectile of the embodiment;
[0020] FIG. 12 is a sectional side elevational view of a projectile
of a embodiment of the present invention, subsequent to firing all
propellant charges;
[0021] FIG. 13 is a sectional side elevational view of a projectile
of a embodiment of the present invention;
[0022] FIG. 14 is a sectional end elevational view of the
projectile of the embodiment;
[0023] FIGS. 15, 16 and 17 depict a projectile assembly of a
embodiment of the present invention; and
[0024] FIGS. 18, 19 and 20 depict a projectile assembly of another
embodiment of the present invention.
DETAILED DESCRIPTION
[0025] In the following description, numerous details are set forth
to provide a more thorough explanation of embodiments of the
present invention. It will be apparent, however, to one skilled in
the art, that embodiments of the present invention may be practiced
without these specific details. In other instances, well-known
structures and devices are shown in block diagram form, rather than
in detail, in order to avoid obscuring embodiments of the present
invention.
[0026] Reference in the specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the invention. The
appearances of the phrase "in one embodiment" in various places in
the specification do not necessarily all refer to the same
embodiment.
[0027] Referring to the drawings it will be appreciated that the
invention can be implemented in various ways for a variety of
projectiles and purposes. The invention may be provided as a single
projectile, as a weapon containing projectiles, or as a barrel
assembly containing stacked projectiles for insertion in a weapon,
for example.
[0028] The embodiments described herein relate to mortar rounds of
up to about 60 mm caliber, it will be appreciated that the
invention finds application in variety of projectile
configurations. In particular, projectile configurations adapted
for axial stacking in a barrel assembly and arranged for sequential
firing, suitably by electronic means, as disclosed in earlier
patent applications originating from either or both of these
inventors.
[0029] FIG. 1A shows a projectile having a body 10 with nose and
tail portions 11 and 12 adapted to be stacked in a barrel with
other similar projectiles. The projectile typically includes a
payload 13 which may be of various kinds such as explosive,
flash-bang, smoke-generating or fire retardant for example.
Propellant charges 14 are contained by cavities within the
projectile and are selectively ignited by respective initiators 15,
preferably inductive elements such as semiconductor bridges (SCBs),
although a range of wired or wireless primer systems may be used.
The charges are held in their cavities by plugs 16 which may be
threaded or glued in place, for example. Ports 17 are provided in
the nose portion for exit of the gases produced by combustion of
the charges. In this example the ports open forwards and propel a
leading adjacent projectile from the barrel. This projectile is in
turn propelled by charges in a trailing adjacent projectile or by
charges in the base of the barrel. The nose portion is preferably
shaped to fit the tail portion of the leading projectile and
similarly the tail portion is shaped to fit the nose portion of the
trailing projectile. This provides a degree of sealing between the
projectiles and may be achieved in various ways.
[0030] FIGS. 1B and 1C are end views of the projectile in FIG. 1A
showing the nose and tail portions. There are four propellant
charges 14 located symmetrically around the longitudinal axis of
the projectile, retained by four plugs 16 and correspondingly
provided with four ports 17 for exit of combustion gases. The
number and arrangement of the charges may be varied to suit the
purpose of the particular projectile. It should be borne in mind
however, that the flight characteristics of the projectile may
change when the charges are selected and ignited, unless all of the
charges are ignited before the projectile is fired from the barrel.
The centre of mass of the projectile may shift for example.
[0031] FIG. 1D shows how two projectiles of this kind may be
stacked in a barrel. The nose portion 11 of the trailing projectile
fits the tail portion 12 of the leading projectile, and preferably
expands the tail portion 12 into a sealing contact with the inside
of the barrel. In this example, a convex curved surface of the nose
portion matches a concave surface in the tail portion, and the tail
portion also includes a rim 18 that contacts the body of the
trailing projectile. One or more charges in the trailing projectile
are selected and ignited to propel the leading projectile from the
barrel with a required kinetic energy. Once the leading projectile
has departed any charges remaining in the trailing projectile are
ignited to produce a predetermined weight and centre of mass in the
trailing projectile, which is now the leading projectile. Each
projectile therefore has reasonably standard and predictable
characteristics for flight.
[0032] FIGS. 1E and 1F show how the last projectile in a stack of
projectiles of this kind may be fired. Propellant charges 14 may be
provided in the base of the barrel as either a separate removable
element 19E, or as a fixed element 19F of the barrel itself. The
charges 14 in each of these figures are contained and ignited in a
manner similar to that of the charges in the projectiles. The
separate base element 19E is preferably loaded down the barrel
before the projectiles while the fixed base element while charges
in the fixed element 19F may be loaded as individual items from the
rear of the barrel. These charges may be selected and fired to
provide a predetermined kinetic energy to the last projectile.
[0033] FIG. 2A shows an alternative projectile having a body 20
with nose and tail portions 21 and 22, adapted to be stacked in a
barrel with other similar projectiles if required. The projectile
includes a payload 23 in this example. Propellant charges 24 are
contained by cavities within the projectile and are selectively
ignited by respective initiators 25, preferably inductive elements
such as semiconductor bridges (SCBs), although a range of wired or
wireless primer systems may be used. The charges are held in their
cavities by plugs 26 which may be threaded or glued in place, for
example. Ports 27 are provided in the tail portion for exit of the
gases produced by combustion of the charges. In this example the
ports open rearwards and propel the respective projectile from the
barrel. The nose portion is preferably shaped to fit the tail
portion of the leading projectile and similarly the tail portion is
shaped to fit the nose portion of the trailing projectile. This
provides a degree of sealing between the projectiles and may be
achieved in various ways.
[0034] FIGS. 2B and 2C are end views of the projectile in FIG. 2A
showing the nose and tail portions. There are four propellant
charges 24 located symmetrically around the longitudinal axis of
the projectile, retained by four plugs 26 and correspondingly
provided with four ports 27 for exit of combustion gases. The
number and arrangement of the charges may be varied to suit the
purpose of the particular projectile, bearing in mind that the
flight characteristics of the projectile may change when the
charges are selected and ignited. The weight and centre of mass of
the projectile may change for example. On the other hand, the
rearward exit ports are less likely to create drag.
[0035] FIG. 2D shows how two projectiles of this kind may be
stacked in a barrel. The nose portion 21 of the trailing projectile
fits the tail portion 22 of the leading projectile, and preferably
expands the tail portion 22 into a sealing contact with the inside
of the barrel. In this example, a convex curved surface of the nose
portion matches a concave surface in the tail portion, and the tail
portion also includes a rim 28 that contacts the body of the
trailing projectile. It will be appreciated that a wide range of
shapes and dimensions may be used in any of the projectiles
described herein. One or more charges in each projectile are
selected and ignited to propel the respective projectile from the
barrel with a required kinetic energy. The projectiles generally
have less predictable flight characteristics than those of FIG.
1A.
[0036] FIG. 3A shows a typical propellant charge 14 or 24 from
FIGS. 1 and 2 in more detail. The charge material 300 is contained
by a metal housing 301, open fully at one end 302 and with a
smaller aperture 303 at the other end 304. A disc 305 of composite
material blocks the aperture 303 but is ruptured on ignition of the
charge material so that combustion gases can pass through the
aperture into a respective exit port. An initiator 306 is threaded
or press-fitted into end 302, based on an SCB igniter in this
example. The initiator includes the SCB 307 connected across a coil
308, both mounted in a fitting 309 of plastic for example. A small
amount of pyrotechnic material 310 surrounds the SCB to act as a
booster in combustion of the charge material. Many alternative
structures could be used for the propellant charges and for the
initiator, which could also be introduced directly to cavities in
the projectile without need of the housing 301 for example.
[0037] Semiconductor bridges are known devices having the
appearance of a microchip with two terminal wires, such as shown in
U.S. Pat. No. 4,708,060 and subsequent US patents. If an electric
potential is placed across these two wires, the semiconductor
bridge releases a small amount of energy, most in the form of heat.
The energy released by the SCB may in some cases be insufficient to
ignite the propellant charges directly and the initiators may
further require a set-up chemical compound (i.e. a compound which
is capable of being initiated by an SCB and will, in turn, ignite
the charge). SCBs can be designed and arranged such that a current
induced between the two terminals can cause energy release. It is
considered that the various means of inducing a current in a coil
of wire using a magnetic field (induction) are well enough
understood by those proficient in the art that such details need
not be discussed here, save one example. It is therefore to be
taken that all such means of providing a suitable firing current,
whether by inducing said current or otherwise, are within the ambit
of this invention.
[0038] FIG. 3B schematically shows an inductive firing system that
may be used to launch the projectiles shown in FIGS. 1 and 2. A
magnetic field suitable to activate an SCB can be induced using a
signal transmitting coil 33 wrapped around the barrel 30, suitably
in the vicinity of projectiles 31 therein, i.e. one transmitting or
primary coil 33.1, 33.2, etc. for each projectile 31.1, 31.2, etc.
The current in the primary coils 33 can be selectively turned on or
off by a fire control unit (FCU) 39 and thus the resulting current
in receiving or secondary coils 35.1, 35.2 can be manipulated in
the same fashion. The primary coils may be connected separately to
the FCU or in series. The FCU may be operated in various ways to
select the kinetic energy and therefore the charges to be ignited
for the next projectile to be fired. A manual user could operate a
rotatable switch that simply indicates 1, 2, 3 . . . or all of the
charges are to be ignited. The user or an automated firing system
determines the kinetic energy required for a particular projectile
according to the environment in which the user or the automated
system is located.
[0039] In order to fire the charges in a designated projectile (for
example projectile 31.2), the FCU 39 applies firing signal current
to the primary coil 33.2 wrapped around the barrel 30 for that
projectile 35.2. The resultant magnetic field induces a current in
the secondary coil 35.2, which is applied to the two terminals of
the initiators 32, 33, 34. Ignition of one or more propellant
charges 36a, 36b, 36c occurs in response to those initiators
arranged to ignite upon receipt of the firing signal.
[0040] SCBs can also be designed such that they will not initiate
due to a simple current but only when a particular "type" of
current occurs. Indeed, SCB technology now offers the ability to
manufacture SCBs that require various and distinct levels of energy
of ignition signal to activate the energetic material. Encoders and
decoders could also be used in conjunction with SCB technology, if
required. Where encoders/decoders and other logic circuits are
employed, a signal modulation scheme may comprise any pulse wave
modulation (PWM), pulse code modulation (PCM) or pulse amplitude
modulation (PAM) scheme, or in any other suitable encoding scheme.
This allows the separate, smaller propellant charges 36 to be
discretely ignited via the common induction coil pairs 33, 35.
[0041] We now turn to consider the use of variations in current to
embed an ignition signal as an example. In order to fire propellant
charge 36a for the designated (or any particular) projectile 35.2
the FCU 39 applies current (with the appropriate modulated
variations embedded within it) to the primary coil 33.2 associated
with that projectile. The resultant current in secondary coil 35.2
(induced by the magnetic field) thus varies in intensity in
proportion to the variations in current the FCU has applied. The
induced current that is delivered to the SCBs thus also varies in
proportion with the variations in intensity of the magnetic field.
Thus the appropriate SCB 32 in propellant load 36a of the
projectile 35.2 can be delivered the appropriate coded signal and
therefore be initiated without the initiation of propellant charges
36b or 36c, through the use of a single induction coil 33 per
projectile.
[0042] It will be appreciated that, upon initiation of a selected
propellant charge or charges 36, the rapid combustion thereof
operates to discharge the associated projectile from the barrel 30.
Where only one propellant charge is initiated, eg. centre charge
36b by SCB 33, the kinetic energy imparted to the projectile will
be considerably lower than imparted when all three propellant
charges 36a, 36b, 36c are initiated.
[0043] FIGS. 4 to 8 of the drawings depict a projectile 45 of
another embodiment of the invention having a projectile body 46
with a cavity 49 wherein a plurality of propellant charges 50 are
disposed longitudinally in the projectile. In contrast, the
propellant charges of the embodiments discussed above were disposed
laterally within the projectile. For reasons of clarity, the
initiators and secondary or receiving coils have been omitted from
these drawings.
[0044] The projectile 45 is depicted in FIG. 4 prior to ignition of
any of the propellant charges 50, which charges are separated from
one another with the cavity 49 by wall members. The propellant
charges 50 are composed of a mouldable material in the present
embodiment, whereby the rearmost charge 50.4 is exposed through the
aperture 58 communicating with the exterior of the projectile
adjacent a tail portion of the body 46. Suitably the wall members
are in the form of sealing discs 51 having edge surfaces with
profiles arranged to wedge into a shallow inwardly tapered wall of
the cavity 47. Accordingly, the shaped propellant charges and
alternating sealing discs may be located into the cavity 49 via the
aperture 58 from the tail 48 of the projectile 45.
[0045] Since the propellant cavity becomes smaller in diameter
toward the head portion 47 of the projectile, if the first loaded
sealing disc 51 is forced toward the head 47 of the projectile,
wedging will occur between the band edge and the tapered interior
wall of the cavity 47, and the disc will retain the forwardmost
charge 50.1 in place. Accordingly, when a similarly directed force
is applied during firing, e.g. the force resulting from combustion
of the second propellant charge 50.2 being initiated, the sealing
disc 51 will further be wedged into place with said interior wall
56. This "wedge-sealing" action aims to reduce the likelihood of
ignition of propellant charge 50.2 causing any sympathetic or
"blow-by" ignition of propellant charge 50.1.
[0046] Ignition of propellant volume 50.1 however will push the
adjacent sealing band in the other direction, both unlocking it and
forcing it toward the tail 48 of the projectile 45. The sealing
disc 51 will not move far before the edge of the sealing disc loses
contact with the cooperating interior wall 56 of the cavity,
thereby allowing burning propellant 50.1 to reach rearward
propellant charge 50.2. The next rearward propellant charge 50.2 is
thus ignited and the process continues rapidly until propellant
volume 50.4 is ignited. In summary, the ignition of a particular
propellant charge 50 will not ignite a propellant charge that is
closer to the nose of the projectile, as explained above.
[0047] FIGS. 5, 6 and 7 show the consequences of igniting a
selected propellant charge in the projectile 45. In FIG. 5 the
third propellant charge 50.3 has been ignited resulting in the
combustion of charges 50.3 and 50.4. In FIG. 6, the second
propellant charge 50.2 has been ignited resulting in the combustion
of charges 50.2, 50.3 and 50.4. In FIG. 7, the first propellant
charge 50.1 has been ignited, resulting in the combustion of all
propellant charges.
[0048] The aperture includes means for resisting the expulsion of
the sealing discs from the cavity, which take the form of a
plurality of inwardly radially extending fingers or catch points 57
(as depicted in FIGS. 4 to 8) to stop or at least resist the
sealing discs 51 from being expelled or otherwise leaving the
projectile cavity 49 entirely. There are several small catch points
57 disposed around the periphery of the aperture 58, as will be
apparent from the view of FIG. 8. A preferred alternative involves
the catch points extending fully across the aperture in the form of
a crossbar to ensure that the discs are contained within the
projectile. In another form, the wall members or sealing discs may
be constructed of a combustible material which has an outer face
treated in order to resist combustion, ie. consumption may only be
initiated by propellant burning forward of the wall member.
[0049] Since it may or may not be viable for the catch points to be
conveniently manufactured as part of the projectile, the catch
points 57 may be formed as a separate component 59 that is
removably retained in the tail portion 48', such as by cooperating
screw threads (not shown), once the cavity 49 has been loaded with
propellant charges 50 and respective sealing discs. This component
modification of the fourth embodiment is shown in FIG. 9.
[0050] In a further modification, the entire cavity portion 49
including the rearward aperture 58 may be formed as a separate
component and similarly removably retained in the projectile body
46. The separate component containing the cavity could
alternatively be formed with the lateral arrangement of propellant
charges and respective expansion bleed ports as described
above.
[0051] In a fifth embodiment of the present invention depicted in
FIGS. 10 and 12 (again omitting the initiators and secondary or
receiving coils), a projectile 60 includes wall members 61 that are
themselves screw threaded into place via cooperating threads 62
provided on the wall member edges and the interior wall of the
propellant cavity 63, respectively. Furthermore, as shown in FIG.
10, the wall members 61 each include sealing plugs 64 that are
wedged into place in the wall members in a similar fashion as the
sealing discs discussed above.
[0052] The sealing plugs 64 are outfitted with a small T-shaped
retaining member 65 that stops or at least resists the plugs from
leaving the projectile cavity 63 entirely. It is presently expected
that the sealing plugs 64 would need to be manufactured as two
pieces (ie. plug and retaining member) and assembled in situ. In a
similar fashion to the fourth embodiment discussed above, the
T-shaped portion is made up of several small catch points, rather
than using the entire ring. However, in this embodiment, the catch
points are a plurality of radially outwardly extending fingers 66
of somewhat cruciform configuration. Also as above, this is so that
when a T-shaped member 65 hits its respective wall member 61, it
does not close off the propellant charge 67 to the exterior of the
projectile 60, as shown in the enlarged cross-sectional view of the
FIG. 11.
[0053] It is presently considered that the T-shaped retaining
member 65 may only be necessary for the screwed-in wall member 61
closest to the rear of the projectile. FIG. 12 shows the end result
of igniting the forwardmost propellant charge 67.1 in this
scenario. The individual propellant charges 67 may be ignited using
only one induction coil per projectile (as discussed above in
relation to FIGS. 1A and 1B) with different coded SCBs for each
propellant charge 67.1, 67.2, 67.3, etc. Accordingly four (4)
different kinds of code responsive SCBs would be required in the
presently illustrated example of the fifth embodiment.
[0054] The above embodiments of the invention all entail the use of
separate (and generally volumetrically smaller) propellant charges.
Typically the operator can elect or an automated fire control
system can determine, to burn 1/4 of the available propellant, 1/2,
3/4 or all of the propellant available to a particular projectile.
However, it is to be understood that propellant volumes need not be
divided in this manner, and in fact can be divided in any way
desired.
[0055] In FIGS. 15 and 16 of the drawings there are shown
components of a projectile assembly of the type described in the
present applicant's International Patent Application No.
PCT/AU02/00932. The earlier invention was concerned with the staged
or sequential ignition a plurality of propellant charges associated
with each projectile in order to reduce in-barrel pressures whilst
maintaining projectile muzzle velocity during firing.
[0056] The applicant has now realized that the present invention
may also find a further application as discussed in relation to
this sixth embodiment. Here each projectile assembly 80 includes a
main projectile body 81 with a head portion 82 and a rearwardly
extending tail portion 83 having a tapered skirt 84, as depicted in
FIG. 15. The projectile assembly 80 also includes a plurality of
propellant cup members 85 which also include a tail portion 86 with
tapered skirt 87 extending rearwardly from a transverse wall 88
similarly to the main body 81, as depicted in FIG. 16. When
assembled together in a barrel (not shown) and subject to an axial
in-barrel load, the wedging action on the tapered skirt portion
effectively seals the respective tail portions against the barrel
bore, as described in the applicant's earlier International
Applications.
[0057] With reference to FIG. 17, it will be seen that the
assembled main projectile 81 and cooperating cup members 85.1, 85.2
effectively from a cavity that is divided by wall members formed by
transverse walls 88 of the propellant cups. Thus by provision of
coded firing signals to the initiators 90 disposed with the
respective propellant charges 89, one, two or all three charges may
be simultaneously fired to achieve a desired muzzle velocity.
[0058] A further embodiment of the invention is depicted in FIGS.
18, 19 and 20, wherein the main projectile body 91 is of the type
including a head portion 92 with rearwardly extending central spine
93 and a band or collar 94 disposed on the head portion 92 of the
projectile body 91, wherein the collar and head portion include
complementary tapered surfaces 95, 96. An auxiliary projectile body
97 also includes a central spine 98 and a similarly configured
collar member 99. In both cases, the collar members are arranged to
provide an operative seal with the bore of a barrel (not
shown).
[0059] With particular reference to FIG. 20, it will be appreciated
that individual propellant charges 101, 102, 103, 104, 105 and 106
may be selectively simultaneously ignited by receipt of firing
signals by respective initiators 111, 112, 113, 114, 115 and 116.
In the present embodiment, each initiator is integrated with a
receiving means that can receive the firing signals directly from a
signal transmitting coil disposed in the barrel (not shown), thus
obviating the requirement for secondary receiving coils.
[0060] Further, the embodiment illustrates how different propellant
charge separating means may be employed together in a projectile
assembly, in that a given pair of charges 103 104 is separated from
other pairs 101-102 and 105-106 by transverse walls of the
auxiliary projectiles 97.1, 97.2, whilst individual charges within
the pair may be separated by respective enclosures in the form of
non-metallic bags 121, 122, 123, 124, 125 and 126.
[0061] In the embodiments discussed above, it will be appreciated
that any propellant charges remaining in the barrel after firing a
particular projectile may be cleared from the barrel by separate
initiation, prior to firing the next projectile in the stack of
projectiles.
[0062] Furthermore, it is envisaged that the propellant division
and selective initiation arrangement of the present invention may
be used within many of the present applicant's other earlier
projectile designs and barrel assembly configurations. Put more
simply, there are existing designs and configurations not mentioned
here that could use the method outlined above of separate smaller
propellant loads and coded SCBs (or other ignition method) to
achieve an electronically selectable range variable projectile.
[0063] For example in the barrel assembly 70 of FIG. 13, with
projectiles 71 axially stacked with a barrel 72 as illustrated in
sectional side elevation, the propellant charge 73 could be split
into four loads 73.1, 73.2, 73.3, 73.4, using bags each containing
a respective initiator 74, 75, 76, 77, as shown in FIG. 14.
[0064] With the addition of different coded SCBs to each bag and an
induction coil pair (not shown) for each projectile we have a
system similar to that of above. It is to be taken that the present
invention is applicable to alternative configurations of projectile
and barrel assemblies (not explicitly mentioned here), including
but not necessarily limited to those of the applicant, which are to
be considered within the ambit of this patent application.
[0065] It is to be understood that the above embodiments have been
provided only by way of exemplification of this invention, and that
further modifications and improvements thereto, as would be
apparent to persons skilled in the relevant art, are deemed to fall
within the broad scope and ambit of the present invention described
above.
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