Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
PCT/AU01/00606
CA 02407787 2002-10-31Received 27 November 2001
1
FORMING TEMPORARY AIRBORNE IMAGES
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to forming temporary airborne images and has
particular application to forming temporary airborne images for entertainment
purposes or advertising purposes. Such airborne images may be produced with
fireworks or other projectiles that deploy a medium in the sky for display.
Discussion of the Background Art
Pyrotechnic displays for entertainment purposes have become very popular at
events with organisations spending large sums of money in order to provide new
and/or interesting airborne displays. To provide individuality, such displays
must be
custom made or organised. Further the displays are limited by the deployment
systems for projecting the fireworks into the sky. This results in the
variations being
limited and/or expensive to produce.
Many displays require large quantities of high explosives to be accumulated at
the display site. Thus displays are often staged from a moored barge or
pontoon.
However the transport of the fireworks to the barge often entails transport
through
heavily populated areas and this poses a potential danger. Also the fireworks
need
to be set-up on site and this is generally labour intensive and time
consuming. The
set-up of fireworks is also very complex in the fusing in order to ensure that
the timing
of the firing is correct.
SUMMARY OF THE INVENTION
We have now found an improved apparatus and method suitable for use in
forming temporary airborne images such as pyrotechnic displays.
Disclosure of the Invention
The improved apparatus and method employ barrel assemblies from which
projectiles for deploying media for creating temporary airborne images such as
pyrotechnic projectiles may be launched from a barrel having a plurality of
such
projectiles axially disposed within the barrel and which are associated with
discrete
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selectively ignitable propellant charges for propelling the projectiles
sequentially
through the muzzle of the barrel. A sealing engagement is provided between
projectiles and barrel so as to prevent rearward travel of an ignited
propellant charge
to the trailing propellant charge.
According to the present invention there is provided a projectile for
deployment from a barrel assembly including a barrel having a plurality of
said
projectiles axially disposed within the barrel and which are associated with
discrete
selectively ignitable propellant charges for propelling the projectiles
sequentially
through the muzzle of the barrel, said projectile including:-
a housing portion containing material for forming temporary airborne images;
an initiator;
a propellant capsule associated with the rear end of the housing whereby the
propellant charge is ignited by activating the initiator;
a fuse link to provide delayed ignition of the pyrotechnic material;
a expandable collar wherein said collar is engaged with the housing for
support and in operative sealing engagement with the bore of the barrel in an
engaged condition and wherein said collar is relocatable relative to the
housing
whereby said collar is disengaged from operative sealing engagement with bore
of
the barrel in a relaxed condition for trailing movement with the housing, and
wherein
the expandable collar provides an open trailing end which engages about the
nose of
a following projectile or the breech end of the barrel in the case of the last
projectile,
and
a pressure member mounted on the housing inwardly of the open trailing end
wherein said collar is relocated from the engaged condition upon ignition of
the
propellant and is retained in a relaxed condition by the pressure member for
passage
through the barrel and out the muzzle of the barrel.
The projectile of the present invention contains material for forming
temporary
air-borne images. The image forming material may include, for example,
explosive
matter, incendiary matter, incandescent or luminous matter or other matter to
provide
a highly visible temporary image. Alternatively, the image forming matter may
include smoke, gas, particles or sheets or strips, such as in the nature of
chaff, or
other material capable of being dispersed to form, an image. The image forming
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matter may also include means for slowing its descent from its dispersed
position,
such as a parachute and the like.
The projectiles may be arranged in the barrel assemblies such that once fired
and the image forming matter deployed, the desired temporary airborne image is
formed. Projectiles containing different image forming matter, either
differing in
colour or form, may be sequentially loaded into each barrel assembly. ,
The image forming matter may be deployed, for example, by explosive means,
by stored energy or by separation of separable parts of the projectile to
expose the
image forming matter or by any other suitable dispersing means.
The projectiles of the present invention are fired from barrel assemblies of
the
type that include a barrel having a plurality of projectiles axially disposed
within the
barrel and which projectiles are associated with discrete selectively
ignitable
propellant charges for propelling the projectiles sequentially through the
muzzle of
the barrel. This invention may utilise barrel assemblies capable of firing a
controlled
rapid fire sequence of mortar like projectiles and being of the general type
described
and/or illustrated in our earlier International Patent Applications such as
PCT/AU94/00124, PCT/AU96/00379, PCT/AU00/00296 and PCT/AU00/00297. . In at
least some of these earlier applications, including the earliest filed
International
Application No PCT/AU94/00124 and PCTIAU96/00379 there are described
arrangements for grouping barrels each containing a plurality of projectiles
so that a
large number of projectiles can be fired in rapid-fire succession. In such
arrangements barrels may be formed from a cylindrical shell having a plurality
of
projectiles axially disposed within the shell for operative sealing engagement
with the
bore of the shell and discrete propellant charges for propelling respective
projectiles.
Suitably the barrel assemblies may be of the low-pressure type which fire
grenade-like projectiles although high muzzle pressure barrel assemblies may
be
used. Respective barrel assemblies may be loaded with different projectiles
and the
barrel assemblies may have different size bores for accommodating different
size
projectiles.
Suitably each projectile includes a trailing collar captively mounted to the
projectile body and when stored in the barrel, extends rearwardly to wedge
against
the nose portion of a trailing projectile body. Suitably the wedging action is
provided
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by a shallow wedge whereby, in use, the trailing end of the collar is expanded
into
operative sealing engagement with the barrel.
The trailing collar may be mounted for limited axial movement relative to the
projectile body and the leading end of the collar formed with an annular
sealing face
engageable with a complementary face formed on the projectile body whereby
rearward movement of the projectile body resulting from the reaction of
propellant
gases thereon forces the its complementary face into sealing engagement with
the
annular sealing face at the leading end of the collar.
The complementary face and the annular sealing face may extend
substantially radially and be formed with complementary sealing features
thereon.
However it is preferred that these faces are complementary part-conical
sealing faces
which wedge into tight sealing engagement with one another. The leading end
part
may also be expandable into operative sealing engagement with the barrel.
Suitably
however the wedging between the part-conical faces are relatively steep faces
whereby the leading end of the collar is not expanded into operative sealing
engagement with the barrel by the wedging action.
Preferably, each projectile is associated with a high-pressure propellant
chamber that exhausts to respective low pressure propulsion chambers formed
between the adjacent projectiles for efficient iow muzzle velocity operation.
The
high-pressure propellant chambers may be formed integrally with the projectile
body
or the trailing collar or be provided at the exterior of the barrel to
communicate
therewith through ports provided through the barrel wall.
The housing may be of any suitable configuration that provides for the
containment of the pyrotechnic material and is suitably configured for
engagement
with the trailing end of the expandable collar of the preceding projectile.
Preferably
the housing is of the type employed with grenade-like projectiles, having
relatively
squat shape although projectiles having elongate housings could also be
employed.
The housing may suitably be formed from biodegradable material and/or
combustible material. This material may be based on a natural product such as
woodchip or a synthetic material, such as a biodegradable polymer.
The selection of materials for use in forming temporary airborne images may
be any suitable materials and preferable may include pyrotechnic material. The
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selection of suitable pyrotechnic material is not narrowly critical and the
person
skilled in the art will be readily able to select appropriate pyrotechnic
materials.
The initiator may preferably be an electronic initiator whereby the
projectiles
may be electronically fired at an infinitely variable frequency up to the
maximum rate
5 of fire. For firing from a barrel assembly according to an aspect of this
invention and
arranged for low pressure, low muzzle velocity, the rate of bring may be
limited by the
time taken for each projectile to leave the barrel and by the time necessary
for the
gas pressure in the barrel to drop sufficiently to enable the firing of the
next projectile.
The electronic initiation may be effected by providing exposed contacts on the
housing whereby a propellant capsule associated with the rear end of the
housing is
ignited by enlivening the electrical circuit made through the contacts. In
order to
mate the contacts with complementary contacts in the barrel there may be
provided
rifling which is configured for aligned-only insertion of the projectile into
the barrel.
Insertion may be performed with the collar mated with the housing in its
engaged
condition or alternatively in its relaxed condition.
The propellant capsule may be of a convenient form and include 'a suitable
propellant. The selection of suitable propellants is not narrowly critical the
person
skilled in the art will be readily able to select appropriate propellants.
The propellant capsule is associated with the rear end of the housing. The
propellant capsule may be engaged with the end of the housing of located
proximate
to the end of the housing in the space between the adjacent projectiles, such
as
within the trailing end of the expandable collar.
The propellant is ignited by activating the initiator such that the ignited
propellant produces combustion products. The combustion products typically
include
a gas and the generation of and expansion of the gas propels the projectile
through
the barrel and out the muzzle of the barrel. The combustion products also
activate
the fuse link. The combustion products may also include burning or hot
materials
that can activate the fuse link such as by causing the fuse to ignite.
The fuse link may be any convenient fusing such as will be apparent to those
skilled in the art of manufacture of fireworks and the like. The fusing may be
selected
such that the combustion products of the propellant capsule activate the fuse
link and
cause the fuse link to ignite the pyrotechnic material at the desired time
after the
projectile has been fire from the barrel assembly. The delayed ignition of the
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pyrotechnic material may be selected to form the desired images in the sky by
igniting the pyrotechnic material of the multiplicity of projectiles at
selected times.
The fuse link may include other fuses or delay means for igniting the
pyrotechnic material. For example timing systems such as electronic timers,
twist
could systems and the like may be used. Alternatively the fuse link may be in
the
form of a laser initiation of the pyrotechnic material.
The expandable collar may suitably be formed from biodegradable material
and/or combustible material. This material may be based on a natural product
such
as woodchip or a synthetic material, such as biodegradable polymers.
The collar is engaged with the housing for support and is in operative sealing
engagement with the bore of the barrel in an engaged condition. The expandable
collar may be supported on the housing through a fusible body part or by a
diaphragm type wall or spider having a central boss which is expanded when
engaged over a hub portion of the housing and which relaxes upon removal from
the
hub portion. The expandable collar suitably has a rearward cylindrical
extension
from its support on the housing and suitably the outer periphery of the
pressure pad
extends adjacent the inner surface of the cylindrical extension.
The collar is relocatable relative to the housing whereby said collar is
disengaged from operative sealing engagement with bore of the barrel in a
relaxed
condition. The collar is retained by the projectile for trailing movement with
the
housing. The expandable collar provides an open trailing end that engages
about
the nose of a following projectile or the breech end of the barrel in the case
of the last
projectile. Suitably the collar extends rearwardly to wedge about the nose
portion of
a trailing projectile body. Suitably the wedging action is provided by a
shallow wedge
whereby, in use, the trailing end of the collar may be expanded into operative
sealing
engagement with the bore of the barrel.
Suitably the configuration of the space into which the ignited propellant
propagates and the propellant properties are such that only low barrel
pressures
occur in use, such as in the order of 2,OOOpsi to S,OOOpsi. Typically the
collar is such
that in its relaxed attitude it does not prevent free movement of the
projectile through
the barrel either for loading purposes or during firing.
A pressure member is mounted on the housing inwardly of the open trailing
end. The collar is relocated from the engaged condition upon ignition of the
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propellant and said collar is retained in a relaxed condition by the pressure
member
for passage through the barrel and out the muzzle of the barrel.
A direction control means may be provided in a bank of barrel assemblies and
may permit uniform pivoting of the barrel assemblies so that the inclination
of the axis
of the barrel assemblies relative to the axis of a pod containing the bank of
barrel
assemblies may be selectively varied to enable a target position relative to
the pod to
be varied. The direction control means may permit individual pivoting of each
barrel
assembly so that the inclination of each barrel axis relative to a pod axis
may be
individually varied to enable a target position or individual target positions
relative to
the pod to be varied. Such individual control may be associated with
individual firing
control of each barrel assembly if desired.
The direction control means may alternatively permit a controlled splaying of
all barrel assemblies so that the area covered at the target zone may be
selectively
varied. Alternatively the direction control means may permit all or some of
the above
variations to be achieved individually or collectively as required.
The pod housing may be of any suitably configuration and may taper towards
its base to enable barrel . assemblies to be supported in a splayed attitude.
The
support means may be fold out legs that may be adjustable if desired. In one
form
the pod has a rectangular pod housing for economy or ease of storage and/or
transport and the base thereof constitutes the support means.
A pod of barrel assemblies may be fired from a marine platform. The pod may
also be fired from an aircraft or from a number of aircraft flying in
formation and if
desired, with the firing coordinated between the aircraft by a suitable
electronic link.
Other aspects of this invention relate to methods of loading a barrel with
projectiles and methods of delivering a pyrotechnic display as will
hereinafter become
apparent.
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 a typical embodiment of the invention and wherein:-
FIG. 1 Is a diagrammatic sectional view of one form of barrel assembly loaded
with two projectiles only;
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FIG. 2 illustrates the construction of a projectile of the embodiment;
FIG. 3 illustrates the housing and collar of a projectile separated for
loading
purposes;
FIG. 4 illustrates the final step iri the loading process; and
FIGS. 5 and 6 illustrate typical cross-sections through the projectile as
illustrated at 5-5 and 6-6 in Fig. 2.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
The barrel assembly 10 illustrated has a rifled barrel 11 loaded with
pyrotechnic projectiles 12. which may be selectively fired through
electronically
controlled ignition in a known manner. Each projectile 12 includes a main body
part
14 having a housing 15 containing pyrotechnic material 16 and a trailing
collar 17
supported on a trailing hub 18 of the body part 14 for limited relative axial
movement.
The collar 17 has~a leading wall 20 which abuts the trailing wall 21 of the
housing 15
and an internally tapered thickened rear end part 24 which engages about a
correspondingly tapered nose part 25 of a trailing projectile 12 to wedge the
collar 17
into sealing engagement with the barrel 11.
The hub 18 also supports a propellant capsule 30 connected by electrical
leads 31 to contacts 32 on the outer cylindrical wall portion 33 of the
housing 12.
Complementary contacts 34, which may be spring loaded ball contacts as
illustrated
or brush type contacts, are supported in the barrel 11. Alignment of these
contacts
34 with the projectile contacts 32 is achieved during the loading process
through use
of non-uniform rifling as described below. In a non-rifled design, the use of
longitudinally separated annular contacts in the barrel wall and on the
projectile can
achieve a similar result.
The hub 18 has a fuse 35 therethrough which extends between the propellant
capsule 30 to a primer 36 in the pyrotechnic material 16 such that the
material 16 will
be exploded a set time after firing the projectile from the barrel 11, this
time being set
by the fuse 35.
Referring to Fig. 2, it will be seen that hub 18 is built up from a leading
part 40
integral with the housing 15 and a trailing part 41 which supports the capsule
30 and
provides a pressure wall 42 which extends outwardly to terminate adjacent the
inner
face 43 of the collar 17. These parts 40 and 42 are assembled together, such
as by
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gluing, after the collar 17 has been located loosely about a necked portion 44
of the
leading part 40. This configuration wherein the collar 17 located on the
necked
portion 44 is illustrated in Fig. 3.
The forward portion 46 of the hub 18 in front of the necked portion 44 is
dimensioned as an interference fit with the central aperture 47 of the leading
wall 20.
. Thus when the wall 20, and the collar 17 which it supports, is forced onto
the hub
portion 46, the collar is expanded outwardly into tight engagement with the
wall of the
barrel 11. This expansion 'is effected once the collar 17 has been inserted
into ~ the
barrel in abutment with a previously located projectile, so as to positively
locate and
hold each projectile in place and in operative engagement with the respective
contacts 34.
Referring to Figs. 3 to 6 it will be seen that the rifling 49 in the barrel 11
is
relatively deep and it is arranged in a non-symmetrical rrranner whereby the
projectiles 12 must be aligned in a unique manner before they can be engaged
and
fed to their fully home position. For loading purposes opposing ones of the
rifling
beads 48 in the housing 15 have diametrically opposed gaps 53 therein (see
Fig. 5)
which are not present in the corresponding bead 52 on the collar 17 as shown
at 53a
(see Fig. 6). Thus, with reference to Figs. 3 and 5, a loading tool 50 having
two spiral
prongs 51, and which is insertable through the gaps 53 about the housing 15 to
abut
the beads 52 at 48b, is used to load the projectile 12, with the collar 17
loosely
supported about the necked portion 44, into the rifled barrel 11. Initially,
the collar 17
is forced rearwardly through the barrel, spiralling into tight engagement with
the
previously loaded projectile 12.
Thereafter as shown in Fig. 4, a load is applied to the nose of the projectile
12
using pushing tool 53 so as to force the hub 18 through the aperture 47 in the
collar
17 which passes over the forward portion 46 of the hub 18, expanding the
collar 17
and locking the projectile in position with the contacts 32, 34 in engagement
with one
another and enabling ignition of the propellant in the capsule 30.
In use when the propellant in a leading capsule 30 is ignited the gas
pressures
act directly on the pressure wall 42 forcing the housing 15 forwardly and
through the
wall 20 until the aperture 47 sits over the necked portion 44. This initial
movement
releases the collar 17 for free travel with the housing 15 from the barrel 11.
At the
same time the released collar provides sufficient gas containment behind the
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projectile 12 for propulsion of the projectile to the desired height before
the activated
fuse 35 ignites the pyrotechnic material 16 through the primer 36.
Further in the above embodiments the collar 17 provides a relatively broad
cylindrical surface which engages closely with the bore of the barrel 11 so as
to
5 assist in preventing passage of ignited gases between the sleeve and the
barrel to
the propellant of a trailing projectile. This seal is enhanced in use through
expansion
of the thickened trailing end 24 upon rearward movement of the following
projectile
as a result of being subject to propulsion pressures in the barrel from
discharge of
the leading projectile.
10 In this embodiment the housing and the collar are formed from compressed
wood particles so that they will burn up with ignition of the pyrotechnic
material. Any
material that does not burn will fall to the ground and degrade. For this
purposes the
wood particles are suitably bonded with a water-soluble glue to accelerate
their
degradation.
The barrel assemblies 10 of this invention may be set up and fired from a
fixed
launch pad such as an on-ground pad or a moored vessel. Preferably however the
projectiles are fired from barrel assemblies supported on an aircraft which
may carry
the fireworks to a display site across minimally occupied terrain such as by
following
a river to a river display site. This will minimise the risk of transporting
large
quantities of high explosive into a densely populated area. Use of an aircraft
as the
launch pad also provides the advantage that projectiles may be launched in
rapid
succession with lateral separation therebetween so as to facilitate accurate
formation
of images spread across the sky, much in the manner of a printer head firing
dots
onto a page to produce a printed image
It will of course be realised that the foregoing description has been given
only
by way of illustrative example of this invention and that all such and other
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 this invention as is
herein set
forth in the following claims
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