MULTI-BARREL ASSEMBLY FEED FOR GUN

Abstract: A gun including a barrel assembly feed (19) for advancing a plurality of barrel assemblies (14) of the type having a plurality of projectiles stacked axially within each barrel assembly (30) together with discrete selectively ignitable propellant charges for propelling the projectiles from each barrel assembly (30), the plurality of barrel assemblies (14) being linked together in spaced apart parallel relationship (15) and locating one or more barrel assemblies (30) in a firing station wherein the firing station operatively supports the one or more barrel assemblies (30), the gun further including a charge initiator associated with the firing station for selectively initiating said discrete selectively ignitable propellant charges of one or more barrel assemblies (30) operatively supported by the firing station. The barrel assembly (30), has an inner barrel (32) made of a hard, non-deformable material and an outer casing (33) of a ductile material. The outer casing may be deformed by the slots (20) and sprocket teeth (21) of a sprocket drive.

Description: MULTI-BARREL ASSEMBLY FEED FOR GUN The invention relates to ordnance, in particular to firearms, including guns, and munitions for firearms. This invention has particular, but not exclusive, application to barrel assemblies having a plurality of projectiles stacked axially within the barrels together with discrete selectively ignitable propellant charges for propelling the projectiles sequentially through the muzzle of the barrels. This invention has particular application to munitions and firearms of the general type described and/or illustrated in my earlier International Patent Applications Nos. PCT/AU94/00124 and PCT/AU96/00459. In my earlier applications there is described arrangements for grouping a plurality of barrels each containing a plurality of projectiles so that a large number of projectiles can be fired simultaneously whereby a module is provided which contains a large number of projectiles for individual firing or firing in selected patterns without the need for reloading. Such grouping of projectiles has the disadvantage that the apparatus is bulky and has a relatively large frontal area and fixed wiring is required for the many individual triggering circuits. This invention aims to alleviate at least one of these disadvantages and/or to provide an alternate arrangement for ready utilisation of a large number of such barrels. With the foregoing in view, this invention in one aspect resides broadly in a gun including a barrel assembly feed for advancing a plurality of barrel assemblies of the type having a plurality of projectiles stacked axially within each barrel assembly together with discrete selectively ignitable propellant charges for propelling the projectiles from each barrel assembly, the plurality of barrel assemblies being linked together in spaced apart parallel relationship and locating one or more barrel assemblies in a firing station wherein the firing station operatively supports the one or more barrel assemblies, the gun further including a charge initiator associated with the firing station for selectively initiating said discrete selectively ignitable propellant charges of the one or more barrel assemblies operatively supported by the firing station. It will be understood that the term "gun" refers to an elongate tube from which projectiles are thrown by the force of an explosive. In the context of this invention the term "gun" particularly relates to firearms which are capable of rapid and continuous fire of projectiles. This capability may be controlled either by a firer having manual control over the firing of the firearm or by an automated system such as one controlled by computer. The present invention has particular application to machine guns for the rapid and continuous fire of bullets. The present invention has particular application to barrel assemblies of the type described in International Patent Application Nos. PCT/AU94/00124 and PCT/AU96/00459. Such barrel assemblies include a barrel; a plurality of projectiles axially disposed within the barrel for operative sealing engagement with the bore of the barrel, and discrete propellant charges for propelling respective projectiles sequentially through the muzzle of the barrel. The projectile may be round, conventionally shaped or dart-like and the fins thereof may be off-set to generate a stabilising spin as the dart is propelled from a barrel which may be a smooth-bored barrel. The projectile charge may be form as a solid block to operatively space the projectiles in the barrel or the propellant charge may be encased in metal or other rigid case which may include an embedded primer having external contact means adapted for contacting an pre-positioned electrical contact associated with the barrel. For example the primer could be provided with a sprung contact which may be retracted to enable insertion of the cased charge into the barrel and to spring out into a barrel aperture upon alignment with that aperture for operative contact with its mating barrel contact. If desired the outer case may be consumable or may chemically assist the propellant burn. Furthermore an assembly of stacked and bonded or separate cased charges and projectiles may be provide for reloading a barrel. Each projectile may include a projectile head and extension means for at least partly defining a propellant space. The extension means may include a spacer assembly which extends rearwardly from the projectile head and abuts an adjacent projectile assembly. The spacer assembly may extend through the propellant space and the projectile head whereby compressive loads are transmitted directly through abutting adjacent spacer assemblies. In such configurations, the spacer assembly may add support to the extension means which may be a thin cylindrical rear portion of the projectile head. Furthermore the extension means may form an operative sealing contact with the bore of the barrel to prevent burn leakage past the projectile head. The spacer assembly may include a rigid collar which extends outwardly to engage a thin cylindrical rear portion of the malleable projectile head inoperative sealing contact with the bore of the barrel such that axially compressive loads are transmitted directly between spacer assemblies thereby avoiding deformation of the malleable projectile head. Complementary wedging surfaces may be disposed on the spacer assembly and projectile head respectively whereby the projectile head is urged into engagement with the bore of the barrel in response to relative axial compression between the spacer means and the projectile head. In such arrangement the projectile head and spacer assembly may be loaded into the barrel and there after an axial displacement is caused to ensure good sealing between the projectile head and barrel. Suitably the extension means is urged into engagement with the bore of the barrel. The projectile head may define a tapered aperture at its rearward end into which is received a complementary tapered spigot disposed on the leading end of the spacer assembly, wherein relative axial movement between the projectile head and the complementary tapered spigot causes a radially expanding force to be applied to the projectile head. The barrel may be non-metallic and the bore of the barrel may include recesses which may fully or partly accommodate the ignition means. In this configuration the barrel houses electrical conductors which facilitate electrical communication between the control means and ignition means. This configuration may be utilised for disposable barrel assemblies which have a limited firing life and the ignition means and control wire or wires therefor can be integrally manufactured with the barrel. A barrel assembly may alternatively include ignition apertures in the barrel and the ignition means are disposed outside the barrel and adjacent the apertures. The barrel may be surrounded by a non-metallic outer barrel which may include recesses adapted to accommodate the ignition means. The outer barrel may also house electrical conductors which facilitate electrical communication between the control means and ignition means. The outer barrel may be formed as a laminated plastics barrel which may include a printed circuit laminate for the ignition means. The barrel assembly may have adjacent projectiles that are separated from one another and maintained in spaced apart relationship by locating means separate from the projectiles, and each projectile may include an expandable sealing means for forming an operative seal with the bore of the barrel. The locating means may be the propellant charge between adjacent projectiles and the sealing means suitably includes a skirt portion on each projectile which expands outwardly when subject to an in-barrel load. The in-barrel load may be applied during installation of the projectiles or after loading such as by tamping to consolidate the column of projectiles and propellant charges or may result from the firing of an outer projectile and particularly the adjacent outer projectile. The rear end of the projectile may include a skirt about an inwardly reducing recess such as a conical recess or a part-spherical recess or the like into which the propellant charge portion extends and about which rearward movement of the projectile will result in radial expansion of the projectile skirt. This rearward movement may occur by way of compression resulting from a rearward wedging movement of the projectile along the leading portion of the propellant charge it may occur as a result of metal flow from the relatively massive leading part of the projectile to its less massive skirt portion. Alternatively the projectile may be provided with a rearwardly divergent peripheral sealing flange or collar which is deflected outwardly into sealing engagement with the bore upon rearward movement of the projectile. Furthermore the sealing may be effected by inserting the projectiles into a heated barrel which shrinks onto respective sealing portions of the projectiles. The projectile may comprise a relatively hard mandrel portion located by the propellant charge and which cooperates with a deformable annular portion may be moulded about the mandrel to form a unitary projectile which relies on metal flow between the nose of the projectile and its tail for outward expansion about the mandrel portion into sealing engagement with the bore of the barrel. The projectile assembly may include a rearwardly expanding anvil surface supporting a sealing collar thereabout and adapted to be radially expanded into sealing engagement with the barrel bore upon forward movement of the projectile through the barrel. In such a configuration it is preferred that the propellant charge have a cylindrical leading portion which abuts the flat end face of the projectile. The projectiles may be adapted for seating and/or location within circumferential grooves or by annular ribs in the bore or in rifling grooves in the bore and may include a metal jacket encasing at least the outer end portion of the projectile. The projectile may be provided with contractible peripheral locating rings which extend outwardly into annular grooves in the barrel and which retract into the projectile upon firing to permit its free passage through the barrel. The electrical ignition for sequentially igniting the propellant charges of a barrel assembly may preferably include the steps of igniting the leading propellant charge by sending an ignition signal through the stacked projectiles, and causing ignition of the leading propellant charge to arm the next propellant charge for actuation by the next ignition signal. Suitably all propellant charges inwardly from the end of a loaded barrel are disarmed by the insertion of respective insulating ruses disposed between normally closed electrical contacts. Ignition of the propellant may be achieved electrically or ignition may utilise conventional firing pin type methods such as by using a centre-fire primer igniting the outermost projectile and controlled consequent ignition causing sequential ignition of the propellant charge of subsequent rounds. This may be achieved by controlled rearward leakage of combustion gases or controlled burning of fuse columns extending through the projectiles. in another form the ignition is electronically controlled with respective propellant charges being associated with primers which are triggered by distinctive ignition signals. For example the primers in the stacked propellant charges may be sequenced for increasing pulse width ignition requirements whereby electronic controls may selectively send ignition pulses of increasing pulse widths to ignite the propellant charges sequentially in a selected time order, preferably however the propellant charges are ignited by a set pulse width signal and burning of the leading propellant charge arms the next propellant charge for actuation by the next emitted pulse. Suitably in such embodiments all propellant charges inwardly from the end of a loaded barrel are disarmed by the insertion of respective insulating fuses disposed between insertion of respective insulating fuses disposed between normally closed electrical contacts, the fuses being set to burn to enable the contacts to close upon transmission of a suitable triggering signal and each insulating fuse being open to a respective leading propellant charge for ignition thereby. A number of projectiles can be fired simultaneously, or in quick succession, or in response to repetitive manual actuation of a trigger, for example. In such arrangements the electrical signal may be carried externally of the barrel or it may be carried through the superimposed projectiles which may clip on to one another to continue the electrical circuit through the barrel, or abut in electrical contact with one another, the projectiles may carry the control circuit or they may form a circuit with the barrel. The barrel assembly feed advances a plurality of barrel assemblies linked together in spaced apart axial relationship. Preferably the barrel assembly feed includes opposed toothed drives which capture the barrels to advance the plurality of barrels. In a preferred embodiment the opposed toothed drives cooperate to hold the at least one barrel assembly therebetween and constitute the firing station. For example the opposed toothed drives may be a pair of opposed sprocket assemblies each having recesses between adjacent teeth which substantially conform to the cross-sectional shape of a respective opposed portion of the at least one barrel assembly so that each respective opposed portion engage simultaneously about the at least one barrel assembly at the firing station to position and operatively support the barrel assembly for firing. Preferably the firing station is capable of operatively supporting a plurality of barrel assemblies for simultaneous firing and more preferably the feed means feeds two or more parallel feeds of linked barrel assemblies so that the plurality of operatively supported barrels is arranged as a cluster of under and over barrels so as to provide a compact frontal area for reduced exposure. A plurality of pairs of such opposed sprocket assemblies may be provided in a side by side or over and under arrangement for simultaneously holding respective barrel assemblies at the firing station. Alternatively the barrel assembly feed may comprise driven opposed feed chains or toothed belts such as opposed belts each having a linear opposed path to provide a multiplicity of side by side firing stations at which the opposed feed chains on toothed belts they cooperate to operatively support a plurality of barrels for firing. Preferably the driven opposed feed chains or toothed belts are endless chains or belts adapted to feed the linked barrel assemblies. However, if desired one of the feed chains may constitute the linking means for linking the plurality of barrel assemblies together. The barrel assembly feeds may extend substantially the full length of the barrel assemblies so as to provide support against internal pressures resulting from firing so that the barrel assemblies size and strength may be minimised to provide for more effective storage of the barrel assemblies in the magazine and if desired the barrel assemblies may be of a disposable form and may be stripped from the chain upon or subsequent to exit from the firing station for ejection. The barrel assemblies for use in the present invention may be of the type described in International Patent Application Nos. PCT/AU94/00124 or PCT/AU94/00459. When such barrel assemblies are used in the embodiment of the present invention whereby a pair of opposed sprockets are employed as the barrel assembly feed and which act as the firing station, the opposed sprocket assemblies must be machined to high tolerances so that the barrel assemblies are not deformed as they are engaged and operatively supported by the opposed sprocket assemblies. We have found that by providing a barrel assembly with a ductile outer casing. Accordingly, in a second embodiment of the present invention there is provided a barrel assembly having a plurality of projectiles stacked axially within an inner barrel, said inner barrel being substantially non-deformable, said plurality of projectiles being stacked together with discrete selectively ignitable propellant charges for propelling the projectiles from the barrel assembly, wherein the barrel assembly further includes a ductile outer casing. The ductile outer casing may be made from a ductile metal such as copper or aluminium or of a plastics material. The plurality of barrel assemblies may be linked by a pair of bands arranged at opposite ends of the barrels wherein the bands are disposed to lie outside the confines defined by the opposed sprocket blocks or equivalent when disposed at the firing station. Alternatively, the opposed sprocket blocks or equivalent may be recessed to accommodate a band which may link the plurality of barrel assemblies substantially along their length. The band or bands may be relatively lightweight flexible material such as steel banding or fibre straps or the like. Alternatively the bands may be rigid links extending between each adjacent pair of barrels in a chain like manner. The bands may cooperate with the opposed sprocket assemblies to operatively support the one or more barrel assemblies for firing. The plurality of barrel assemblies linked together may be provided in the form of a magazine to facilitate convenient storage and transport as well as to the facilitate stoppage free feeding of barrel assemblies into the firing station. The charge initiator may be any suitable initiator for selectively initiating the discrete selectively ignitable propellant charges of the one or more barrel assemblies. Suitable charge initiating systems have been described hereinabove with reference to the barrel assemblies of International Patent Application Nos. PCT/AU94/00124 and PCT/AU96/00459 The charge initiator associated with the firing station may be incorporated into the barrel assembly feed but preferably each barrel assembly has correspondingly disposed firing circuit contact means which are exposed when the barrels are held at the firing station for contact by a stationary initiator which is brought into contact with the barrel contacts when they are operatively supported at the firing station. The one or more barrel assemblies operatively supported by firing stations may preferably engage barrel extensions which form part of the gun. The one or more barrel assemblies are preferably brought into co-axial alignment with the barrel extensions such that the barrel extensions sealably engage the one or more barrel assemblies. In a preferred embodiment a multiplicity of barrel extensions may be mounted on a rotating housing whereby the barrel extensions are brought into position co-axial with the one or more barrel assemblies simultaneously with the one ore more barrel assemblies being brought into operative support at the firing station. The gun of the present invention may also include other features and components associated with guns of the prior art, including butts, handles, sights, fixed mounts, and the like. 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 front end view of a gun according to one aspect of the invention, and FIG. 2 is a detail view of one form of feed mechanism particularly suited to feeding and supporting thin wall barrel assemblies. FIG. 3 is an isometric view of the form of feed mechanism shown in Fig. 2. FIG. 4 is a detailed view of another form of feed mechanism particularly suited to feeding and supported thin walled barrels. FIG. 5 is an isometric cross section of a barrel assembly of one form of the invention. FIG. 6 is an isometric projection of a sprocket mechanism similar to that shown in Fig. 3 incorporated into a gun having barrel extensions incorporation thereon. FIG. 7 is a cut away drawing of Fig. 6. The gun 10 illustrated in Fig. 1 includes a central supporting structure 11 which is fixed or able to be aimed and supporting magazines 12 and 13 containing live and spent barrel assemblies respectively at opposite sides thereof. The barrel assemblies 14 in the magazines are linked together as shown in Fig. 2 and Fig. 3 by linking webs 15 which maintain the barrel 14 in spaced apart parallel relationship in a flexible manner forming barrel-chains. in this embodiment, each magazine 12 and 13 hold two barrel-chains which feed individually through breech mechanisms 16 and 17 disposed one above the other in the central supporting structure 1 1. The arrangement is such that the respective live barrel assemblies in the magazine 12 are fed through the breech mechanism to respective multiple firing positions at which the active barrel assemblies are clamped with their axes parallel and parallel to the line of sighting of the weapon ready for firing by control means. The control means makes sequential operative contact with the barrel assembly triggering circuit when the barrel assemblies are fed to the respective firing stations. The triggering arrangement is such that once held in position, the control contacts are made so that an operator may selectively fire one or more of the barrel assemblies simultaneously with selected sequential control of the firing of projectiles in each barrel assembly. In the illustrated embodiment, six barrel assemblies may be maintained in firing positions, three in each of the upper and lower barrel-chains. Typically each barrel assembly would contain 20 rounds and the magazines 12 and 13 would be capable each of holding 200 barrel assembly. Thus the weapon could store 4,000 rounds and be capable of a firing rate in the order of 2,700 rounds per minute with six rounds available for simultaneous firing. The chain feed mechanism is suitably of the type illustrated in Fig. 2 and Fig. 3 and comprises opposed rotatable chain blocks 19 coupled for simultaneous timed rotation such that slots 20 formed between the sprocket teeth 21 engage tightly about the barrel assemblies and provide support therefore throughout their length during firing. In this manner, the necessary strength for resisting firing pressures may be built into the rotating blocks in the breech mechanism enabling thin wall barrel assembly to be provided for ease of manufacture and/or economy of manufacture or light weight. For example the barrel assemblies may be formed from as carbon fibre barrel assemblies enabling maximum rounds to be available for a given vehicle or aircraft load capacity. It will be seen that the weapon has a reduced exposed profile as the magazines may be mounted remote from the breech mechanisms for storage in areas where they may be located in a shielded position for example. The drive means for operating the feed mechanism may be gas or electric or otherwise as desired and the rounds may be of any suitable size. The barrel assemblies may be disposable or reloadable. Fig. 4 shows three opposed rotatable chain blocks 19 aligned vertical with adjacent chain blocks 19 contra rotating so as to feed the linked barrel assemblies 14 through the firing station formed by the opposed slots 20 in opposite directions. Fig. 5 shows a barrel assembly 30 having a bore 31 into which projectiles and explosive charges may be aligned axially. The barrel assembly 30 has an inner barrel 32 made of a hard, non deformable material and an outer casing 33 made of a ductile material such as copper or aluminium. The outer casing 33 may be deformed by the slots 20 and the sprocket teeth 21 of a sprocket drive as shown in Figs. 2, 3 and 4. Figs. 6 and 7 shows the sprocket assembly of Figs. 2 and 3 incorporated into a gun. The housing 40 and the rotatable barrel housing 41 retain the barrel assemblies 14 into abutment with each other and provide a resilient seal to enable the barrel assemblies to be accurately positioned and retained in position during the discharge of the rounds contained in each barrel. The barrel extension frame 41 holds eight barrels 42 which rotate cooperatively with the sprockets 19 such that the barrel extensions 42 align with the barrel assemblies 14 when the barrel assemblies 14 are operatively supported between the sprockets 19. 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 herein set forth.

Claims: THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A gun including a barrel assembly feed for advancing a plurality of barrel assemblies of the type having a plurality of projectiles stacked axially within each barrel assembly together with discrete selectively ignitable propellant charges for propelling the projectiles from each barrel assembly, the plurality of barrel assemblies being linked together in spaced apart parallel relationship and locating one or more barrel assemblies in a firing station wherein the firing station operatively supports the one or more barrel assemblies, the gun further including a charge initiator associated with the firing station for selectively initiating said discrete selectively ignitable propellant charges of the one or more barrel assemblies operatively supported by the firing station. 2. A gun according to claim 1 wherein the firing station operatively supports a plurality of barrel assemblies for simultaneous firing. 3. A gun according to claim 2 wherein the barrel assembly feed is adapted to feed two or more parallel feeds of linked barrel assemblies so that the plurality of operatively supported barrel assemblies is arranged as a cluster of under and over barrels so as to provide a compact frontal profile. 4. A gun according to any one of claims 1 to 4 wherein the barrel assembly feed includes driven opposed feed chains or toothed belts each adapted to have a linear opposed path at the firing station at which firing station the driven opposed feed chains or toothed belts cooperate to operatively support one or more barrel assemblies for firing. 5. A gun according to claim 4 wherein the driven opposed feed chains or toothed belts are endless chains or belts adapted to feed the linked barrel assemblies. 6. A gun according to any one of claims 1 to 5 wherein the charge igniter is incorporated into the feed means and wherein each barrel assembly has correspondingly disposed firing circuit contact means which correspondingly disposed firing circuit contact is exposed when the barrel assemblies are held at the firing station for contact by a stationary charge igniter or by charge igniter which is brought into contact with the barrel assemblies contacts after they are positioned in operative support at the firing station. 7. A gun according to any one of claims 1 to 6 wherein the barrel assembly feed includes opposed toothed drives which operatively support the barrel assemblies therebetween at the firing station. 8. A gun according to claim 7 wherein the opposed toothed drives are a pair of opposed sprocket assemblies each having recesses between adjacent teeth which substantially conform to the cross-sectional shape of a respective opposed portion of the barrel assemblies in the chain so that each engage simultaneously about an opposed barrel assembly portion at the firing station to operatively support the barrel assembly for firing. 9. A gun according to claim 8 wherein a plurality of pairs of opposed sprocket assemblies may be provided in a side by side arrangement for simultaneously holding respective barrel assemblies at the firing station. 10. A gun according to any one of claims 7 to 9 wherein the opposed tooth drives extend substantially the full length of the barrel assemblies so as to provide support against internal pressures resulting from firing so that the size and strength of the barrel assemblies may be minimised to provide for more effective storage of the barrel ^assemblies in the magazine 1 1. A gun according to any one of claims 7 to 10 wherein the barrel assemblies are linked by a band disposed outside the confines defined by the opposed sprocket blocks when disposed at the firing station. 12. A gun according to any one of claims 7 to 1 1 wherein the opposed sprocket blocks are recessed to receive the band. 13. A magazine fed weapon according to any one of claims 1 to 12 wherein the band includes is one or more steel bands of fibre straps. 14. A barrel assembly having a plurality of projectiles stacked axially within an inner barrel, said inner barrel being substantially non-deformable, said plurality of projectiles being stacked together with discrete selectively ignitable propellant charges for propelling the projectiles from the barrel assembly, wherein the barrel assembly further includes a ductile outer casing. 15. A barrel assembly according to claim 14 wherein the ductile outer casing is formed from copper, aluminium or a plastics material.

Inventors: O'DWYER JAMES MICHAEL, O'DWYER, JAMES, MICHAEL
Applicants: DWYER JAMES MICHAEL O, METAL STORM LTD, METAL STORM LIMITED, O'DWYER, JAMES, MICHAEL
Application year: 2000
Main classification: F41A3
IPC codes: F41A3, F41A9, F41F1, F42B5