AU2004201568A1 - Projectile firing apparatus - Google Patents

Description

P:CO'J]VnttiS lIIAU 21279662 specificafoc 1 04.doc-16/'04 -1I- PROJECTILE FIRING APPARATUS TECHNICAL FIELD This invention relates to apparatus for firing projectiles and has particular application to methods of and apparatus for firing projectiles for military use, although this invention is also applicable to civilian uses such as described in our earlier filed International application No. PCT/AUOO/00296, BACKGROUND ART The military applications of firing projectiles are well known, such as firing grenades, firing radar deflecting chaff and missile decoy packages. In military applications such as firing grenades, each cartridge case carries a projectile assembly containing a single grenade. Accordingly the relatively slow rate of delivery of grenades provides a significant constraint on the applications or utility of the equipment.

Recent developments involve projectiles which are fired from a barrel assembly having a plurality of projectiles arranged in-line within the barrel and which are associated with discrete selectively ignitable propellant charges for propelling the projectiles sequentially through the muzzle of the barrel. Sealing engagement is provided between projectiles and barrel so as to prevent rearward travel of an ignited propellant charge to the trailing propellent charge. Such barrel assemblies will be referred to hereinafter as of the type described. Such arrangements are illustrated in our earlier International Patent Applications.

Conventional barrel assemblies have the disadvantage that significant time may be required to position or reload them for sustained firing on a selected target or targets. This set-up time may be unsuitable for applications where time is of the essence, such as for setting up defences to multiple inbound missiles.

Known assemblies may also have a disadvantage by way of limitations on the volume of propellant that can be provided for each projectile.

OBJECT OF THIS This invention aims to provide for an improved weapon of the type described.

P 'Op~rOmafcwu.taXI MR 1A732217 662 upeiflr. O04.doe.I5YUMA0 -2- DISCLOSURE OF INVENTION In one aspect the invention lies in a barrel assembly including a barrel having a plurality of external chambers containing respective propellant charges, a plurality of projectiles stacked nose to tail within the barrel and having respective expansion spaces for propellant gases, each projectile having a corresponding external chamber and an expansion space, each chamber having a port that conveys propellant gas from the chamber into the expansion space for propulsion of the respective projectile, and a control system that ignites the propellant charges to create the propellant gases and propel the projectiles sequentially from the barrel.

In another aspect the invention lies in a barrel for a barrel assembly, having a plurality of external propellant chambers located along the barrel, each chamber having propellant ignition means and a port into the barrel for exit of propellant gases, wherein in use, the barrel is stacked with projectiles in nose to tail arrangement, each projectile having a respective external chamber loaded with a propellant charge and a corresponding expansion space for gases within the barrel, and the projectiles are fired from the barrel sequentially by ignition of the propellant charges.

In another aspect the invention lies in a projectile for a barrel assembly, having a housing, a nose part and a tail part, adapted for stacking in a barrel in nose to tail arrangement with other projectiles, wherein the tail part defines an expansion space for propellant gases received from a propellant chamber that is external to the barrel.

In another aspect the invention lies in a firing system for an assembly having a barrel with a stack of projectiles, including propellant charges arranged externally of the barrel for propelling respective projectiles sequentially from the barrel, propellant igniters arranged for initiating combustion of the propellant charges, expansion spaces between the projectiles to receive products of the combustion of the propellant charges, and ports in the barrel for conveying the combustion products from the propellant charges into the expansion spaces.

This specification also describes other inventions that have been claimed in parent specifications.

P.%Opai&calJsuI I;1lIAU2ZL2L79662 pcilutim. 04AdvA5/04W0 -3- 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 wherein:- FIGS. 1 to 4 illustrate barrel assemblies; FIG. 5 is a diagrammatic sectional end view of a cluster of barrels; FIG 6A is a cutaway view of a pod of grenade firing barrel assemblies; FIG. 6B is a diagrammatic view of a ffirther pod of projectile fifing barrel assemblies; FIG. 7 illustrate an aerial weapons system; FIG. 8 illustrates an unmanned aerial vehicle; FIG. 9 is an underside view of one of the pod catrers of the aerial vehicle of Fig. 8; FIG. 10 is a diagrammatic cross-sectional view of a pod of splayable barrel assemblies; and FIG. 11I illustrates a further aerial system.

DESCRIPTION OF PREFERRED EMBODIMENTS The barrel assembly 10 illustrated in Fig. 1 has multiple grenade carrying projectiles 11, for grenades of substantially known form, loaded in a rifled barrel 12 to impart spin upon firing for activating an arming device.

However a rupturable propellant cup or high pressure chamber 13 is fixed to the projectile 11 for discharging from the barrel with the projectile to clear the barrel for firing the following projectile. This chamber 13 exhausts through ports 14 into the barrel space between the stacked projectiles 11I which space forms a low pressure chamber Each projectile 11 includes a projectile body 17, which in this embodiment is a grenade housing 18 housing a grenade 22, and a trailing sleeve 19 which is retained thereon for limited relative axial movement. The sleeve 19 has a head part 20 which tapers inwardly to an internal collar 21 which extends into a complementary shaped external recess 23 formed in the grenade housing 18. The sleeve 19 tapers outwardly at its rear end 24 to engage over a corresponding tapered leading face 25 of the projectile 11 stacked therebehind.

In use, as disclosed in our earlier inventions, loading of the projectiles 11I into the PiO~etcnnodm l1%1 A1JZM2] 79662 spccificalan 14 oc* 15/04 -4barrel 12 forms a wedge type seal 26 between the leading end of the sleeve 19 and the trailing tapered face 27 of the head part 20 which prevents the ignition of the leading propellant spreading about the grenade housing to the propellant in the following round.

Loading also effects a further wedge type seal 28 between the rear end 24 and the leading face 25 and expands the rear end 24 into operative sealing engagement with the barrel 12. Thus the sleeve forms a barrier to spreading of ignition thereabout to propellant charge in the trailing round.

Firing of the leading projectile 11I releases the leading seal while maintaining the sleeve 19 captive with the grenade housing 18 but maintains an operative seal at the rear end of the sleeve with the barrel 12. As the pressure propelling the projectile is relatively low, in the order of 3000psi, only minimal sealing is required.

The barrel assembly 30 illustrated in Fig. 2 is similar in configuration to that illustrated in Fig. 1, the main difference being the manner in which the sleeve 31 is retained on the grenade housing 32 and the configuration in which the sleeve 31 confines a smaller low pressure chamber 33 between adjacent projectiles 35 into which the high pressure chamber 36 exhausts through ports 38.

The sleeve 31 also has a shallow wedge 34 at its leading end which may be expanded into sealing engagement with the barrel during loading but which is released upon firing during the initial forward movement of the housing 32 and upon subsequent impact of the propellant chamber 36 with the back face of the return 37.

The barrel assembly 40 illustrated in Fig. 3 is also similar in configuration to that illustrated in Fig. 1, the main difference being the wedge sealing angles a and 3 between the trailing sleeve 31' and the projectile housing 42. In this embodiment which is more suited to low pressure low muzzle velocity applications, the opposed ends of the trailing sleeve 31' formned by the sealing angles a and j3 of between 30' and 55' are sufficiently blunt as to resist outward splaying into sealing engagement with the barrel under the influence of propellant pressures. Typically these would be in the order of 3000psi to with muzzle velocities of about 70m/sec and 250mn/sec respectively.

It will be seen that the bulbous nose part 43 of the projectile housing 42 is hollow for carrying explosives, or fuel as referred to in relation to Fig. 11. As in the embodiments illustrated in Fig 1 and 2 the propellant 37 in the high pressure chamber 42 is selectively PN~pa ak madt~amNIB [iAUD~I 2179t62 spmiftcutio IO4doc-LWi4 ignited to expel high pressure gases through the trailing ports 39 into the low pressure chamber 33' by a detonator 16. The detonator is triggered through an electrical circuit which uses the projectile column as one part of the circuit, the barrel 41 being made of insulating material or so lined, and with the circuit completed by an embedded insulated wire 29 leading from the primer 16 to a contact 29' on the projectile surface which is aligned when loaded, with a complementary contact 44 supported in the barrel 41.

Alignment of the contacts can be achieved in a barrel and projectile located by rifling grooves during the loading process. In a non rifled design, the use of a annular contact in the barrel wall can achieve a similar result.

The barrel assembly 45 illustrated in Fig. 4 substantially corresponds in mechanical configuration to the Fig. 3 embodiment. However the high pressure chamber 46 Is disposed externally of the barrel and communicates with the low pressure chamber 47 through aligned ports 48 and 49 in the wall of the barrel 50 and trailing sleeve 51 respectively. As shown cutaway in Fig. 5 the high pressure chamber 46 is of such configuration that it will fit snugly into the space bounded by the adjacent side walls 50 of further barrels of a cluster of barrels Further in each of the above embodiments the sleeve provided a relatively broad cylindrical surface which engages closely with the bore of the barrel so as to assist in preventing passage of ignited gases between the sleeve and the barrel. Further in the embodiments illustrated in Figs. 2, 3 and 4 the inward projections on the sleeve engage within complementary recesses formed in the housing and provide a labyrinth type seal across the inner face of the sleeve.

In all the above embodiments the propellant in the high pressure chamber is adapted to be ignited by electronically controlled ignition means, which ignition means are described in our earlier International Patent Applications.

As illustrated in Fig. GA, a typical weapon includes a cluster of barrel assemblies adapted to fire grenades 56 and contained in a pod 57 such that a selected number of near simultaneously exploding grenades may be fired at a time. The grenades 56 are fired selectively from the pod 57 by computer control. The weapon in the illustrated embodiment contains ninety-eight barrel assemblies each containing stacked grenades 56 and having selectively ignitable internal or external propellant charges. In this P.VOpf~LcL~.Ltnn1\IIAU2;12179662 spcdtid. 104 d 15/04/04 -6embodiment the pod 57 is carried on a turret mounting 58 whereby the barrels may be swivelled about vertical and horizontal axis for aiming purposes.

Suitably 40mm grenades 56 are used as the projectiles because of their ready availability. The grenades 56 are fired selectively by computer control from the pod 57 which is envisaged will contain ninety-eight barrel assemblies each containing stacked grenades 56 and having selectively ignitable internal or external propellant charges. The grenades 56 may be selectively fired to form a controlled impact array of exploding grenades on the zone to be investigated.

By way of example, using such a barrel assembly in a pod of ninety-eight barrels that would measure approximately 350mm x 700mm in cross section, with each barrel loaded with six projectiles, and with each projectile similar in size to a conventional military grenade, a barrel length of 900mm would be required and the assembly would provide a projectile capacity of five hundred and eighty-eight projectiles. This configuration would be suitable for short range applications such as for delivering projectiles from downwardly facing barrels. For longer range delivery fewer projectiles would be accommodated in each of such barrels or longer barrels would be used and more propellant would be utilised to achieve higher muzzle exit velocities.

The maximum rate of fire per barrel is expected to be as high as 20,000 projectiles per minute and the maximum rate for the combined ninety-eight barrels would be 1,960,000 projectiles per minute, assuming that all barrels are fired simultaneously at the maximum rate.

For a ninety-eight shot burst firing the leading round from each of the ninety-eight barrels, the rate is infinitely variable and which may be a ninety-eight shot burst fired at a rapid frequency.

The above ninety-eight barrel pod is one example of a range of performance specifications that could be available. Different performance specifications can be generated by altering the component parts of the pod. For example, a pod may be preloaded such that the nature and weight of the explosive and/or projectile may vary between individual barrels in the pod, or within a barrel.

A plurality of such pods 57 may be carried on a vehicle and arranged whereby each pod 57 may be selectively directed toward a desired target and fired at a selected rate.

P:pri'NciW12IAWUt2I79M2 qwifleadoo 104 do-15104104 -7- Alternatively the pods 57 may be fired collectively at a single target.

In a further example illustrated in Fig. 6B, a plurality of pods 57' may be mounted together on a trainable mount 58'. The aiming and firing of the barrel assemblies can be controlled by a radar fire control system 59' or other suitable weapons control system. In one form of barrel assembly 55', each barrel is 2.25 metres long and has an outside diameter of 20 nin. The combined propelling charge/projectile assembly length is 50 mm.

Leaving 0.25 metres of the barrel free, 40 projectile assemblies together with their associated propellant charges can be pre-loaded into the barrel. Each pod 57' has a crosssectional dimension of 0.75 metres by 0.75 metres for example, and therefore accommodates approximately 1200 barrel assemblies. Thus, a pod can be pre-loaded with 48000 projectiles.

This enables significant fire-power to be associated with a relatively small weapon and a very high discharge rate to be achieved, bearing in mind the firing rate of each individual barrel assembly may be significantly in excess of the rate achievable by conventional automatic weapons. The barrel assemblies may be formed as a relatively lightweight, honeycomb structure which will be very stiff. If desired, the barrels may be arranged to focus at a point relatively close to the weapon with a view to counteracting the Spreading tendencies produced by the expansion of the hot explosion gases radiating in an outwards direction. Alternatively a box-like baffle could be used to prevent the immediate outward spread of the gases. This baffle may be slidably supported about the outer barrel section for extension past the muzzle ends of the barrels during firing. A further optional manner of alleviating this perceived tendency would be to slightly stagger the firing of the projectiles.

In the embodiment illustrated in Fig. 7, the grenades 56 are fired downwardly from a pair of such pods 57, only one of which is shown, carried by a helicopter 59 to provide bombing coverage of a tract of land. The density of such bombing and the area of land covered by the bombing can be controlled by controlling the variables such as rate of fire, elevation and speed of the aircraft.

The unmanned combat aerial vehicle 60 illustrated in Figs 8 and 9 carries six such pods 57 in cases 61 under the wings 62 at each side of the fuselage 63. It is envisaged that each pod could contain six 40mm grenade pods with one hundred barrel assemblies per P:\pwW'mflt9-AtIU IMT]2I7%62 spcci.u IO4dcc-151G4D4 -8pod and with six grenades in each barrel. This would provide a loaded capacity of 7,200 grenades representing a payload of about 3,600lb.

In this embodiment aiming of the barrels containing the grenades 56 would be achieved by remote control of the aircraft which may carry a video camera or the like for assisting its control remote from an operator.

The projectile firing pod 70 is illustrated diagrannatically in Fig. 10 and cutaway to illustrate only two barrel assemblies 71 of the type described which would be contained within a rectangular pod housing 72 in spaced apart relationship suspended from an upper wall 73 from respective ball type mountings. 74.

Each barrel assembly 71 extends downwardly through the fixed ball-like mountings 74 to direction control means 75 which in this embodiment is able to individually or collectively control the barrel assembles 71 for movement to an inclined attitude at one side or the other of their normal vertical position illustrated or to the front or back of that normal vertical position or to a combination of those attitudes as required.

For this purpose, each barrel assembly is provided with a cylindrical positioning block 78 supported rotatably about its lower end for eccentric motion about the axis of each barrel assembly. An intermediate wall 80 is apertured to closely receive each cylindrical positioning block 78. The vertical position of the intermediate wall 80 is controlled by a hydraulic ram 81 supported on the base wall 82 of the pod housing 72.

Extension and/or refraction of the ram 81 will move the intermediate wall 80 in a vertical direction restraining the respective apertures for movement along respective fixed axes so that, in the illustrated barrel assemblies, as the intermediate wall 80 moves downwardly, the lower ends of the barrel assemblies 71 will be moved inwards towards one another causing the barrel assemblies to splay outwardly relative to one another due to the fixed spacing of their upper ball mountings 74, Accordingly, it will be seen that by controlling the position of the hydraulic ram 81 the barrel assemblies can be positioned with their axes vertical and parallel, inclined to the vertical and parallel, or with their axes in a splayed attitude.

Each positioning block may be selectively rotated about the lower end of the barrel assembly on which it is mounted by extension or retraction of a further hydraulic ram 84 supported on the intermediate wall 80 and extending to a track 83 in the outer side wall of P~wpmawinmfatml M hI I ALM 1217966 qwafcadov iO4dcc-5/0/ -9the respective positioning block 78. The configuration of the track could be such that normal vertical movement of the intermediate wall 80 will not cause rotation of the blocks 78 in the direction of the arrow 85 unless the ram 84 is extended or retracted.

It will be seen that the vertical ram 81 connected to the intermediate wall 80 acts collectively on all barrel assemblies so as to move them in unison while individual horizontal rams 84 are provided for each barrel assembly 71.

These rams 84 may be individually controlled independent of the ram 81. Thus, for example, whereas the positioning blocks 78 are illustrated in the drawings arranged at opposing offsets with respect to the illustrated barrel assemblies 71, one of the positioning blocks could be rotated through 7800 by its ram 84 so as to arrange both cylindrical positioning blocks 78 with their axes parallel to one another and at an identical offset to the axes of the associated barrel assemblies 71.

In this configuration, operation of the vertical ram 81 would pivot both barrel assemblies identically to one side or the other from the vertical, while at intermediate positions of one positioning block 78 relative to the other, splaying of the barrel assemblies could be achieved. Of course, both sets of rams 84 and 81 could be actuated simultaneously and be controlled by a suitable controller 86 to achieve a significant variation in target direction and spread of the fall of projectiles fired therefrom. In addition, the configuration of the impact pattern may be varied within a predetermined zone. The barrel assemblies may also be controlled to provide a limited amount of turreting to achieve long range tight grouping of projectiles.

A projectile firing pod may have an in-built remote controller 86, which may receive positional information from orientation sensors mounted on, or associated with, the barrel assemblies or from the ram positions. The positional information relating to the orientation of the barrel assemblies in space can be derived, for example when deployed on an aircraft, from the aircraft inertial navigation system (INS). If required, the orientation information can be combined with terrain data, such as provided by a radar altimeter or digital terrain data, to provide range to the target site. It will be appreciated that projectiles may be readily delivered and deployed very quickly to a site even though that site may be off-level and thereafter the projectile firing pod may be remotely controlled to fire projectiles at a common or at varying inclinations to the vertical to achieve the desired fall P:aprlcWlcm6MSTll\11I AUlI2179663 niecadu 044x-15c-t04?04 of projectiles at the impact zone. Also, the proportions of the impact pattern may be varied or maintained constant with varying target impact zones.

The drives for rotating the blocks 78 could be independent of the intermediate wall such as rotary drives with flexible or splined drives to the base of the barrel assemblies.

Further, the base 82 could be inclined to the side walls or be movable to an inclined position to provide a coarse inclination toward the target zone with final aiming control achieved remotely by the direction control means A typical application of pods described above, as illustrated in Fig. 11 could be to fire a selected array of projectiles containing fuel to be dispersal therefrom in a controlled manner and pattern to form a defined fuel/air cloud to be detonated by further projectiles fired from the same pod or pods.

For example the fuel containing projectiles could form a fuel/air cloud 90 in a substantially conical shape and detonation could be effected simultaneously from a plurality of locations 91 about the upper portion of the cone to form a focused explosion directed to the desired target 92.

The size and height of the cloud could 90 be selected to deliver high pressure shock waves to a localised area. This could be utilised to explode a land mine field, as a lethal anti-personnel attack or, by further elevating the cloud 90 to provide a concussive nonlethal attack against ground troops.

It will of course be realised that the above has been given only by way of illustration 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 defined by the appended claims.

Claims (16)

1. A barrel assembly including: a barrel having a plurality of external chambers containing respective propellant charges, a plurality of projectiles stacked nose to tail within the barrel and having respective expansion spaces for propellant gases, each projectile having a corresponding external chamber and an expansion space, each chamber having a port that conveys propellant gas from the chamber into the expansion space for propulsion of the respective projectile, and a control system that ignites the propellant charges to create the propellant gases and propel the projectiles sequentially from the barrel.

2. An assembly according to claim I wherein each projectile has a tail structure that determines the respective expansion space in conjunction with the respective trailing projectile.

3. An assembly according to claim 2 wherein the tail structure is a trailing sleeve that interacts with the projectile to form a seal with the barrel against passage of propellant gases.

4. An assembly according to claim 2 wherein the tail structure includes a passage aligned with the port of a respective external chamber for flow of propellant gas from the external chamber into the respective expansion space.

An assembly according to claim 1 wherein each external chamber is a relatively high pressure chamber for detonation of the propellant charge and the expansion space is a relatively low pressure chamber into which propellant gases flow following detonation.

6. A barrel for a barrel assembly, having a plurality of external propellant chambers located along the barrel, each chamber having propellant ignition means and a port into the F:'Octac~wcls~ hi l LI AU2Ul2179662 spciflenio 104 dA-5[04/04 -12- barrel for exit of propellant gases, wherein in use, the barrel is stacked with projectiles in nose to tail arrangement, each projectile having a respective external chamber loaded with a propellant charge and a corresponding expansion space for gases within the barrel, and the projectiles are fired from the barrel sequentially by ignition of the propellant charges.

7. A barrel according to claim 6 wherein each external chamber is a relatively high pressure chamber for detonation of the respective propellant charge and the corresponding expansion space is a relatively low pressure chamber that receives gases from the external chamber.

8. A projectile for a barrel assembly, having a housing, a nose part and a tail part, adapted for stacking in a barrel in nose to tail arrangement with other projectiles, wherein the tail part defines an expansion space for propellant gases received from a propellant chamber that is external to the barrel.

9. A projectile as in claim 8 wherein the tail part includes an entry port for passage of the propellant gases from the external chamber into the expansion space.

A projectile as in claim 9 wherein the entry port is adapted for alignment with an exit port of the external chamber.

11. A projectile as in claim 8 wherein the tail part defines the expansion space in conjunction with the nose part of a respective trailing projectile.

12. A firing system for an assembly having a barrel with a stack of projectiles, including: propellant charges arranged externally of the barrel for propelling respective projectiles sequentially from the barrel, propellant igniters arranged for initiating combustion of the propellant charges, expansion spaces between the projectiles to receive products of the combustion of the propellant charges, and P:OpariakclalsmnUI u 1AU2\12179662 pccificaion 104.doc-]6/04104 -13- ports in the barrel for conveying the combustion products from the propellant charges into the expansion spaces.

13. A system according to claim 12 wherein the expansion spaces are determined by trailing sleeves on the projectiles.

14. A barrel assembly substantially as herein before described with reference to figure 4.

15. A barrel substantially as herein before described with reference to figure 4.

16. A firing system substantially as herein before described with reference to figure 4. DATED this 16 t h day of April, 2004 Metal Storm Limited by DAVIES COLLISON CAVE Patent Attorneys for the Applicants RENIPW