Note: Descriptions are shown in the official language in which they were submitted.
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BARREL ASSEMBLY WITH TUBULAR PROJECTILES FOR FIREARMS
TECHNICAL FIELD
The invention relates to munitions and firearms. This invention has
particular,
but not exclusive, application to a barrel assembly having a plurality of
rounds
stacked axially within a barrel together with discrete selectively ignitable
propellant
charges for propelling the rounds sequentially through the muzzle of the
barrel. Such
barrel assemblies will be referred to hereinafter as "of the type described".
BACKGROUND ART
This invention concerns barrel assemblies for munitions and firearms,
particularly of the type described, such as illustrated in earlier
International Patent
Applications Nos. PCT/AU94/00124 and PCT/AU96/00459 filed by the present
inventor.
Whilst tubular rounds are known in certain limited applications such as
supersonic projectiles, the applicant is unaware of any tubular rounds
suitable for
stacking within a barrel with selectively ignitable propellant charges, and
particularly
no tubular rounds suited to barrel assemblies of the type described.
DISCLOSURE OF INVENTION
It is desirable to provide barrel assemblies for electronically controlled
munitions and firearms, particularly of the type described, that are adapted
to firing
tubular type rounds, and to provide tubular rounds for that purpose.
According to one aspect this invention provides a barrel assembly of the type
described including:
a barrel having a muzzle;
a plurality of tubular rounds stacked axially within the barrel and arranged
for
operative sealing engagement with the barrel;
closure means interposed between the tubular rounds for effecting both an
operative barrel closure between the tubular rounds; and
a selectively ignitable propellant charge within each round and ignitable for
propelling an adjacent leading round and associated closure means through the
muzzle of the barrel.
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Preferably the tubular rounds are stacked in abutting relationship, although
they could be spaced apart by the propellant. It is also preferred that each
round
includes a tubular body having a closure means associated with at least its
trailing
end.
The closure means may also act to close the leading end of the trailing round.
Alternatively, separate closure means could be used for the leading and
trailing ends
of each round provide that the closure for the leading end is made inoperative
upon
ignition of the charge therein to enable the combustion effects to propel the
leading
round from the barrel.
The closure means may be arranged to discard from the tubular body or it may
be fixed to the leading tubular body. The tubular rounds may be configured to
have
desired flight characteristics by their aerodynamic form. The form of the
inner face of
the tubular body, when used with a discarding closure means, may act to
maintain
axial alignment of the round with the flight path. Alternatively the tubular
body may
be weighted whereby one end is heavier than the other end.
The closure means is suitably a closure wall member sandwiched between
adjacent tubular body portions. Each closure wall member may extend to and
engages sealably with the barrel. Alternatively the tubular rounds may have
complementary outer end wall portions which abut or lie closely adjacent one
another, with the closure wall member being sandwiched between inner end wall
portions.
In the former arrangement, the closure wall member may be sandwiched
between end faces of adjacent tubular rounds. The closure wall member may be
of a
form which does not deform under operational conditions. Alternatively, the
peripheral portion of the closure wall member may be formed so as to spread
outwardly between the adjacent tubular rounds into operative sealing
engagement
with the barrel by axial compression applied by the end faces. For low
pressure
applications, such deformation for effecting a tight sealing engagement with
the
barrel should not be necessary.
The end faces of adjacent tubular rounds may extend radially of the barrel or
the end faces of adjacent tubular rounds may be formed to engage with
respective
complementary wedging surfaces on the peripheral portion of the sandwiched
closure wall member.
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The tubular bodies of adjacent rounds may overlap one another to provide a
telescoped engagement between adjacent rounds. For this purpose the rounds may
include outer end wall portions which overlap inner end wall portions of the
adjacent
round and the closure wall members may be sandwiched between inner
complementary end wall faces of the telescoped rounds.
If desired the telescoped portions of adjacent rounds may include a thin
walled
portion which may expand outwardly into sealing engagement with either the
adjacent telescoped round portion so as to prevent escape of propellant into
the
barrel or blow by into the adjacent propellant charge. Alternatively the
outward
expansion may be of the outer telescoped portion so as to enhance the sealing
engagement of the round being fired and the barrel.
Each sandwiched closure wall member may also be arranged to react to
propellant charge pressure against its leading face to seal against the end
face of the
trailing round to prevent blow-by ignition of the charge contained in the
adjacent
trailing round. Such reactive sealing may also occur between abutting end face
portions of the rounds and/or between the leading round and the closure wall
member.
The ignition of the propellant charges may be such as is described in my
earlier International applications. For this purpose each selectively
ignitable
propellant charge may include an electrically actuated primer connected to a
pair of
spaced annular contacts extending about the round and contacting respective
electrical contacts protruding through the barrel and suitably associated with
electronic control means.
The closure means may be integral with the rounds and may include wall
segments which may move, or a wall which may expand, forwardly from a closed
attitude to an open attitude and substantially barrel conforming attitude.
When in the
closed attitude the wall segments may react to ignition of a leading
propellant charge
to maintain or enhance the closing effect of the closure means.
Suitably each round with its propellant charge is prepared prior to loading
into
the barrel but if desired the barrel may be loaded by sequentially loading a
round
tubular body having on open leading end, propellant charge followed by closure
of
the open end, either as a separate operation or as a result of placing the
next round
tubular body into its located position.
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In another aspect, the invention resides in a round for firing from the barrel
assembly of a munition or firearm, said round including:
an open ended tubular body adapted for loading into a barrel of the barrel
assembly and for operative sealing engagement with the barrel;
a closure wall member adapted to be interposed between said tubular body
and the tubular body of an adjacent round for effecting an operative barrel
closure
between rounds; and
a selectively ignitable propellant charge within the tubular body of the
adjacent
round, which propellant charge is ignitable for propelling the tubular body of
said
round through the muzzle of the barrel.
BRIEF DETAILS OF THE DRAWINGS
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 typical embodiments of this invention and wherein:
FIGS. 1A to 1 D diagrammatically illustrate, in section, one form of the
invention and its mode of operation;
FIGS. 2A to 2D diagrammatically illustrate, in section, a further embodiment
of
the invention and its mode of operation;
FIG. 3 is a perspective view illustrating one round of the embodiment
illustrated in FIGS. 2A to 2D;
FIG. 4 diagrammatically illustrates, in section, another form of the
invention;
and
FIG. 5 diagrammatically illustrates, in section, yet another form of the
invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the embodiment illustrated in FIGS. 1A to 1D, the barrel assembly 10 has a
plurality of rounds 11 stacked in axial abutting relationship within the
barrel 12 and
which are adapted to be fired electrically or otherwise in sequence, such as
is
illustrated in the inventor's earlier International applications or as is
otherwise known
in the art.
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Each round 11 comprises a tubular body 13 associated with a barrel closure
member 14 disposed between and separating adjacent tubular bodies 13a, 13b,
13c
and 13d from one another, and with a propellant charge 15 arranged behind a
closure member 14. The propellant charge 15a is, for example, supported within
a
5 trailing tubular body 13b between respective barrel closure members 14a and
14b.
In the embodiment a further propellant charge 15d is contained in a rear
extension 16
of the barrel assembly 10 for propelling the rearmost tubular body 13d.
It will be seen in FIG. 1A that the leading annular end 18 of each body 13
extends inwardly and rearwardly to form a part conical end face 19. The part
conical
end face co-operates with a complementary part conical face 22 formed about
the
outer trailing peripheral portion of the barrel closure member 14, as shown in
FIG.
1 B. A further complementary part conical leading face 23 is formed about the
outer
edge of the closure member 14, as shown in FIG. 1 C. The further complementary
part conical leading face 23 is associated with a return face 24 so as to
provide a
recess 25 which receives the complementary shaped trailing end wall 26 of each
tubular body 13.
It will be seen that the end walls 26 return inwardly whereas the remainder of
the tubular body 13 is of constant tubular section, although it could be
formed to
provide a venturi shape through the body 13 if desired.
The return wall portion 26 is captured by the closure member 24 during firing
of the leading body 13 from the barrel as illustrated in FIG. 1 B. As depicted
in FIG.
1 C the closure member 14 may be discarded from the tubular body 13 during
flight,
such as the result of rotation of the body 13 due to rifling provided in the
barrel 12 or
it may stay with the body 13 during flight as depicted in FIG. 1 D. For this
purpose,
the closure member 14 could be secured to the body 13 by screwing, pinning,
gluing,
swaging or otherwise as required.
In use, the barrel assembly 10 is stacked with rounds 11 wherein an empty
tubular body 13a is the leading projectile. When the leading propellant charge
15a is
ignited in the next adjacent body 13b, the resultant gas pressure will act
upon both
the leading and trailing end closure members 14a, 14b enclosing the ignited
propellant charge. The action of the gas pressure causes the leading closure
member 14a to be propelled from the barrel 12 together with the leading body
13a.
At the same time the gas pressures will force the trailing closure member 14b
into
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axial compression with the trailing body 13b, resulting in radial expansion of
the part
conical end face 19 of the trailing body.
This arrangement will wedge the leading annular end 18 of the trailing body
13b into sealing engagement with the barrel 12 and wedge the closure member
14b
into sealing engagement with the part conical end face 19, ensuring there is
no
leaking of combustion gasses into the propellant of the next trailing charge
15b.
Thereafter, the empty body 13b as shown in FIG. 1 B may be propelled from the
barrel assembly 10 by ignition of the propellant 15b in the next trailing body
13c.
In the embodiment of the barrel assembly illustrated in FIGS. 2A to 2D, each
round 30 has a tubular body portion 31 provided with outwardly converging wall
segments 33 which abut or overlap to form respective closures for the tubular
body
31. These segments 33 provide a central land portion 35 which mutually abut
when
the rounds 30 are disposed along the length of a barrel 36.
The preferred form of wall segments 33 is an opposing pair of segments as
illustrated in FIG. 3, disposed between body extensions 38 having end walls 39
which abut when disposed in the barrel 36.
The leading segments 33 open to lie alongside the barrel 36 upon ignition of
the propellant 37 contained within the round 30. Propellant ignition also
propels the
leading round 30, shown partially in FIG. 2A. This action provides the next
leading
round 30 with a substantially tubular body 31 in the barrel, which body is
closed only
at its rear end by the trailing closure segments 33 which diverge rearwardly
to
provide a land portion 35, as shown in FIG. 2B. The land portion 35 abuts the
land
portion 35 formed at the front of the forwardly diverging segments 33 of the
next
adjacent trailing round 30.
When the propellant 37 in that next adjacent trailing round 30 is ignited, its
leading segments 33 will open to place the pressure of the combustion gasses
into
contact with the trailing faces of the segments 33 at the trailing end of the
leading
body 31 and thus propel that body from the barrel 36. In this action, the next
body is
made ready for firing.
The segments could alternatively be a plurality of substantially triangular
segments having their bases disposed about the periphery of the body 31 and
extending inwardly to form a pyramid shaped closure.
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If desired, the trailing closure segments 33 may be coupled to the tubular
body
31 by hinge means 32, which segments open upon exiting the barrel due to air
pressure passing through the tubular body 31, as illustrated in FIG. 2D. If
desired,
these segments 33 may be provided with flights or other projections to
stabilise the
flight of the body 31 or make it spin as required.
It will be seen from the above that the high pressure resulting from
propellant
burn which propels the leading body 31 acts on the rear section of the
trailing round,
pressing it against the leading edge of the following round, and sealing
against
undesired blow-by ignition of the propellant in that following round, thus
ensuring
consistent operation of the firearm at a desired firing rate.
In operation barrel closure members 14 may be the free floating and behave
as a discarding section, separated by the rotation of the tubular round if
fired from a
rifled barrel, or separated by air pressure during flight. With the section
discarded the
round would have improved aerodynamic performance for relatively long range
engagements, such as need when fired from an aircraft or when used to engage
incoming missiles in such areas as ship self defence.
However, in certain applications there may be advantage in fixing the closure
members 14 to the tubular body 31. For example, the closed rounds may be fired
from multiple barrels against a buried land mine. Such a round would then act
to
scoop earth into the body 31 and carry it away from the mine location. That
effect
would be into addition to the usual disturbance of earth due to the kinetic
impact of
the round on the ground. Firing multiple rounds from multiple barrels thus has
the
potential to provide improved means of exposing and/or neutralizing buried
land
mines.
The rounds make contact with each other while stacked in a barrel, and are
positively located in their intended position. In effect, the rounds utilize a
cartridge
case which also doubles as the projectile itself.
In the barrel assembly 40 illustrated in FIG. 4, the barrel 41 is shown
cutaway
at its leading end or muzzle so that only the two rearmost rounds 42 and 43
are
illustrated, a leading round (not shown) having been recently fired from the
barrel. It
will be seen that in this embodiment the rounds 42 and 43 are telescoped, with
the
outer leading end portion 44 of the trailing round 43 extending about the
inner trailing
end portion 45 of the intermediate round 42.
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All end face portions are part conical with the respective complementary outer
end face portions 46 and 47 terminating adjacent one another, and the inner
end
face portions 48 and 49 terminating in spaced apart relation with one another
and in
abutting relationship with the closure wall member 50. The closure wall member
includes a peripheral portion 52 also having a part conical end face 54. In
this
embodiment the telescoped wall portions 44 and 45 are relatively long and are
formed as a close fit, one within the other.
In use during discharge of the leading round (not shown), propellant pressure
acts against the closure wall member 50 of the intermediate round 42 which
contains
the ignited propellant. This urges the end face 54 of the wall member 50
against the
complementary inner end face portion 49 of the trailing round 43. During exit
of the
leading round, pressure thus acts on the leading ends 47, 49 of the trailing
round 43
and forces the intermediate projectile 42 outward and rearward to wedge the
trailing
face 46 into the leading outer face 47 effecting a seal therebetween. The
outward
pressure also expands the leading end 51 of the leading outer end portion 44
of the
trailing round 43 info engagement with the barrel 41.
The inner faces 48, 49 also wedge into sealing engagement with the
peripheral portion 52 of the closure wall member 50, preventing blow by
ignition of
the propellant for the trailing round 43. Furthermore, the propellant pressure
will tend
to expand the inner trailing end portion 45 of the intermediate round 42 into
tight
engagement with the outer leading end portion 44 of the trailing round 43 so
as
minimise leakage to the barrel 41.
As illustrated a primer 55 is located within each selectively ignitable
propellant
charge 56 and connected to positive and negative slip ring type contacts 57,
58
spaced along the outer periphery of the rounds 42, 43. The barrel 41 is
provided with
correspondingly located spring contacts 53, 59 protruding into the barrel for
effecting
a contact with the respective contact rings 57, 58.
Suitable electronic controls are provided for actuating the primer and
igniting
the propellant charges 56. These peripheral contacts 57, 58 are suitably
utilised on
all the illustrated rounds such as is shown in FIG. 3.
The barrel assembly 60 illustrated in FIG. 5 is similar to the embodiment
illustrated in FIG. 4, the difference being reversal of the rounds 61 and the
annular
skirt portion 63 provided in the barrel 64. That is in the FIG. 4 embodiment,
the
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rounds 42, 43 have an inner wall which reduces rearwardly whereas the inner
wall 62
of the rounds 61 is of constant diameter throughout the majority of its length
and then
expands outwardly. It is believed that this arrangement will provide a more
aerodynamic configuration but less effective sealing than the embodiment of
FIG. 4.
INDUSTRIAL APPLICATION
The barrel assembly and tubular rounds of this invention could be utilised in
small arms but it is envisaged that they would be more suited to rounds of
2Omm
diameter and above. It will be seen that each barrel closure may cooperate
with the
leading annular end of the adjacent tubular round, either by forcing the
annular end
outwardly into contact with the bore of the barrel and wedge a barrel closure
into
sealing engagement with the barrel or the leading annular end, or by causing
the
closure member to wedge into close sealing contact with the part-conical inner
end of
the tubular round and without significant expansion of that leading end into
engagement with the barrel.
This wedging may be achieved by maintaining the wedging angles relatively
steep, by providing a stop on the leading end which stops rearward movement of
the
closure at a point at which sealing between the closure and tubular round is
effected
but prior to radial expansion of the leading end of the tubular round
occurring.
Alternatively the leading end may be formed sufficiently robust to resist
outward
splaying under the influence of the wedging action created by the propulsion
force
from a leading round. Such a sealing action is more suited to low pressure,
low
muzzle velocity applications.
While illustrated as being stacked rounds supplied in situ in a barrel, the
rounds may also be supplied individually to a weapon from an external magazine
by
conventional means. For this purpose each round may include the closure wall
suitably fixed to the trailing end of the round and a wad closure or the like
for
securing the propellant in the round.
The barrel assemblies of this invention which utilise open tubular rounds may
also be useful for firing from underwater locations such as from ships,
submarines or
as concealed land based surtace piercing defence installations. For example
submarines may utilise such barrel assemblies for self defence, for underwater
mine
destruction or anti-torpedo or missile activity.
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It will of course be realised that the above has been given only by way of
illustrative example of the invention and that all such modifications and
variations
thereto as would be apparent to persons skilled in the art are deemed to fall
within
the broad scope and ambit of the invention as is set forth in the following
claims.
