Forming temporary airborne images

Abstract

Barrel assembly ( 10 ) includes rifled barrel ( 11 ) loaded with several pyrotechnic projectiles ( 12 ) for selective firing by an electronically controlled system. Each projectile ( 12 ) includes body ( 14 ), housing ( 15 ) containing pyrotechnic material ( 16 ), and trailing collar ( 17 ) supported on trailing hub ( 18 ) of body ( 14 ) for limited axial movement. Collar ( 17 ) includes leading wall ( 20 ) abutting trailing wall ( 21 ) of housing ( 15 ) and an internally tapered thickened rear part ( 24 ) engaging nose ( 25 ) of trailing projectile ( 12 ) to wedge into sealing engagement with barrel ( 11 ). Hub ( 18 ) supports propellant capsule ( 30 ) connected by electrical leads ( 31 ) to contacts ( 32 ) on outer cylindrical wall ( 33 ) of housing ( 12 ). Complementary contacts ( 34 ) are supported in barrel ( 11 ). Alignment of contacts ( 34 ) with contacts ( 32 ) occurs during the loading process. Fuse ( 35 ) extends between capsule ( 30 ) and primer ( 36 ) so that material (16) explodes a set time after firing projectile ( 12 ) from barrel ( 11 ).

1 . 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: 
 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.    
     
     
         2 . A projectile according to  claim 1  wherein the image forming material is selected from the group consisting of explosive matter, incendiary matter, incandescent and luminous matter.  
     
     
         3 . A projectile according to either  claim 1  or  claim 2  wherein the projectile includes an explosive means for deploying the image forming material.  
     
     
         4 . A projectile according to either  claim 1  or  claim 2  wherein the housing is formed from separable parts for deploying the image forming material.  
     
     
         5 . A projectile according to any one of  claims 1  to  4  wherein the housing is formed from materials selected from the group consisting of biogradable materials and combustible materials.  
     
     
         6 . A projectile according to any one of  claims 1  to  5  wherein the initiator is an electronic initiator whereby the projectiles are selectively electronically fired at a variable rate of fire.  
     
     
         7 . A projectile according to any one of  claims 1  to  6  wherein the propellant capsule is engaged with the end of the housing of located proximate to the end of the housing in the space between the adjacent projectiles.  
     
     
         8 . A projectile according to any one of  claims 1  to  7  wherein fusing is 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.  
     
     
         9 . A projectile according to any one of  claims 1  to  7  wherein the fuse link is selected from the group consisting electronic timers, twist count fuses, and laser initiation.  
     
     
         10 . A projectile according to any one of  claims 1  to  9  wherein the expandable collar is formed from biodegradable material and/or combustible material.  
     
     
         11 . A projectile according to any one of  claims 1  to  10  wherein the expandable collar has a rearward cylindrical extension from its support on the housing and the outer periphery of the pressure member extends adjacent the inner surface of the cylindrical extension.  
     
     
         12 . A projectile according to any one of  claims 1  to  11  wherein the collar extends rearwardly to wedge about the nose portion of a trailing projectile body.  
     
     
         13 . A projectile according to  claim 12  wherein 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.  
     
     
         14 . A projectile according to any one of  claims 7  to  13  wherein the barrel assemblies are of the low-pressure type which fire grenade-like projectiles.  
     
     
         15 . A projectile according to any one of  claims 1  to  14  wherein projectile is associated with a high-pressure propellant chamber that exhausts to respective low pressure propulsion chambers formed between the adjacent projectiles for efficient low muzzle velocity operation.  
     
     
         16 . A projectile according to  claim 15  wherein the high-pressure propellant chamber is formed integrally with the projectile body.  
     
     
         17 . A barrel assembly including a plurality of projectiles according to any one of  claims 1  to  16  wherein said barrel assembly includes a barrel having a plurality of said 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.  
     
     
         18 . A barrel assembly according to  claim 17  wherein including a direction control means for pivoting of the barrel assembly so that the inclination of the axis of barrel assemblies relative to the axis of a pod containing a bank of barrel assemblies may be selectively varied to enable a target position relative to the pod to be varied.  
     
     
         19 . A barrel assembly according to  claim 18  wherein direction control means permits 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.