Diversionary device

Abstract

A diversionary device has a housing containing a pyrotechnic cartridge with an ignitable fuse. A firing arrangement includes an ignition cap containing a primer charge. Passageways in the housing and ignition cap define a first flow path from the primer charge to a region of the housing in which the fuse is located through which flash from the primer charge can flow to ignite the fuse. A further flow path connects said region of the housing with the exterior of the housing to supply the fuse with oxygen for reliable burning. The device may be a multi-burst device containing a plurality of cartridges and the first flow path may include a flash divider for directing a proportion of the flash from a primer charge on to the fuse of each cartridge. The housing may be separable to allow replacement of the cartridges.

I/we claim: 
     
         1 . A diversionary device comprising a housing having an outer housing portion defining an internal cavity, at least one replaceable pyrotechnic cartridge mounted in the housing and at least partly located within the internal cavity, the cartridge having a first end containing an ignitable fuse, the housing defining a region in which the first end of the at least one cartridge is located, a firing arrangement mounted to the housing and including an ignition cap containing a primer charge, the housing and ignition cap defining a first flow path from the primer charge to the housing region to provide a fluid path through which a proportion of a flash of heat and pressure given off by a primer charge in the ignition cap when it is fired is can flow to ignite the fuse, in which a further flow path is provided to fluidly connect the housing region with the exterior of the housing. 
     
     
         2 . A diversionary device as claimed in  claim 1 , in which the outer housing portion includes a hollow side wall region closed at either end by means of an end closure to define the internal cavity, at least one of the end closures comprising an end closure member releasably mounted to the side wall region, the firing arrangement being mounted to a first of the end closures, a first passageway being defined through the first end closure and forming part of the first flow path, the ignition cap being mounted so as to close one end of the first passageway and having a second passageway defined there through, the second passageway communicating with the first passageway in the end closure and also forming part of the first flow path. 
     
     
         3 . A diversionary device as claimed in  claim 2 , in which the second passageway comprises a stepped bore having an enlarged diameter region proximal to an outlet end of the passageway to define a chamber in which carbon given off by the fuse and explosive charge on detonation can collect. 
     
     
         4 . A diversionary device as claimed in  claim 2 , in which the ignition cap comprises a head portion and a spigot portion projecting from the head portion, at least part of the spigot portion being received in a first end region of the first passageway, the primer charge being located in a recess in an outer surface region of the head portion and the second passageway extending from the recess to a distal end of the spigot for communication with the first passageway. 
     
     
         5 . A diversionary device as claimed in  claim 4 , in which the spigot is in screw threaded engagement with the first end region of the first passageway. 
     
     
         6 . A diversionary device as claimed in  claim 3 , in which the ignition cap has a flange portion which extends over an outer diameter portion of an outer surface of the primer charge to retain the primer charge in the recess. 
     
     
         7 . A diversionary device as claimed in  claim 2 , in which the first end of the at least one cartridge is located in a chamber forming part of the first passageway, the further fluid path comprising one or more further passageways defined within the first end closure to fluidly connect the chamber with the exterior of the housing. 
     
     
         8 . A diversionary device as claimed in  claim 7 , in which the, or each, further passageway opens at one end into the internal cavity for fluid communication with the exterior of the housing through the vent openings and at the other end into the first passageway for fluid communication with the chamber and the first end of the at least one cartridge. 
     
     
         9 . A diversionary device as claimed in  claim 2 , in which the region of the housing in which the first end of the at least one pyrotechnic cartridge is located is in direct fluid communication with the internal cavity defined by the outer wall portion of the housing for fluid communication with the exterior of the housing through the vent openings. 
     
     
         10 . A diversionary device as claimed in  claim 9 , in which the housing region comprises a chamber in the first end closure member, the first end of the at least one cartridge is located in the chamber with a clearance so that the chamber is in fluid communication with the internal cavity about the at least one cartridge. 
     
     
         11 . A diversionary device as claimed in  claim 9 , in which the first end of the at least one pyrotechnic cartridge is spaced inwardly from the first end closure member and so is located within the internal cavity for fluid communication with the exterior of the housing through the vent openings. 
     
     
         12 . A diversionary device as claimed in  claim 1 , in which a plurality of pyrotechnic cartridges are contained within the housing, each cartridge having a first end containing an ignitable fuse, the first end of each cartridge being located within a region of the housing which is in fluid communication with the exterior of the housing through the further flow path. 
     
     
         13 . A diversionary device as claimed  claim 1 , in which the housing comprises an inner housing portion received within the internal cavity in spaced relation to a side wall region of the outer housing portion, the inner housing portion defining at least one cartridge chamber containing a pyrotechnic cartridge, the cartridge chamber having an outlet arranged to direct substantially all of the explosive force from the cartridge when detonated outwardly in a radial direction relative to a central longitudinal axis of the housing towards the outer wall portion. 
     
     
         14 . A diversionary device as claimed in  claim 13 , in which the inner housing portion has more than one chamber, each containing a respective pyrotechnic cartridge, each chamber having an outlet arranged to direct substantially all of the explosive force from a pyrotechnic cartridge detonated in the chamber outwardly in a radial direction relative to the central longitudinal axis towards the outer housing portion. 
     
     
         15 . A diversionary device as claimed in  claim 14 , in which the inner housing portion has three chambers each containing a respective pyrotechnic cartridge. 
     
     
         16 . A diversionary device as claimed in  claim 13 , in which the vent openings are arranged so that they comprise no more than 50%, or no more than 60% or no more than 70% of the total area of the outer housing portion in regions immediately radially opposite the, or each, chamber outlet. 
     
     
         17 . A diversionary device as claimed in  claim 16 , in which the vent openings are arranged in zones that are circumferentially offset from the outlet openings of the chambers such that regions of the outer housing portion that are located radially opposite the, or each, of the chamber outlets have no vents. 
     
     
         18 . A diversionary device as claimed in  claim 13 , in which the inner housing portion is generally cylindrical, the, or each, chamber being formed in an outer diameter region of the cylindrical inner housing portion. 
     
     
         19 . A diversionary device as claimed in  claim 18 , in which the inner housing portion has more than one chamber, each containing a respective pyrotechnic cartridge, each chamber having an outlet arranged to direct substantially all of the explosive force from a pyrotechnic cartridge detonated in the chamber outwardly in a radial direction relative to the central longitudinal axis towards the outer housing portion, the chambers being circumferentially equi-spaced about the inner housing portion, and generally cylindrical or part cylindrical in shape, each chamber having a longitudinal axis parallel with a central longitudinal axis of the inner housing portion, a radially outer edge of the, or each, chamber breaking through the outer diameter of the inner housing portion to form the outlet. 
     
     
         20 . A diversionary device as claimed in  claim 12 , in which the device comprises an arrangement located in the first flow path for dividing the flash so that a proportion of the flash is directed on to the fuse of each of the cartridges. 
     
     
         21 . A diversionary device as claimed in  claim 20 , in which the housing comprises an inner housing portion received within the internal cavity in spaced relation to a side wall region of the outer housing portion, the inner housing portion defining a plurality of cartridge chambers, each containing a pyrotechnic cartridge, each cartridge chamber having an outlet arranged to direct substantially all of the explosive force from its respective cartridge when detonated outwardly in a radial direction relative to a central longitudinal axis of the housing towards the outer wall portion, the arrangement for dividing the flash comprising a projection on one end of the inner housing portion which is shaped to direct a proportion of the flash towards the fuse of each of the pyrotechnic cartridges. 
     
     
         22 . A diversionary device as claimed in  claim 21 , in which the outer housing portion includes a hollow side wall region closed at either end by means of an end closure to define the internal cavity, at least one of the end closures comprising an end closure member releasably mounted to the side wall region, the firing arrangement is mounted to a first of the end closures, a first passageway being defined through the first end closure and forming part of the first flow path, the ignition cap being mounted so as to close one end of the first passageway and having a second passageway defined there through, the second passageway communicating with the first passageway in the end closure and also forming part of the first flow path, and the projection has a generally conical portion with an apex positioned substantially centrally of a second end of the first passageway in the first end closure. 
     
     
         23 . A diversionary device as claimed in  claim 22 , in which grooves are provided in the outer surface of the conical projection, the grooves being spaced and aligned so as to direct a proportion of the flash on to the fuse of each of the pyrotechnic cartridges. 
     
     
         24 . A reloadable multi-burst diversionary device, the device comprising a housing having an outer housing portion having a side wall region and end closures at opposed ends of the side wall region to define an internal cavity, the housing further comprising an inner housing portion received within the outer housing portion, the inner housing portion defining one or more chambers, each chamber for receiving a replaceable pyrotechnic cartridge comprising a housing containing a pyrotechnic charge and a fuse with a time delay, the device further comprising a removable ignition cap for containing a primer charge and a fluid passage arrangement through which a proportion of a flash of heat and pressure given off by a primer charge when it is fired in the ignition cap is directed into each chamber, the device further comprising a firing arrangement for selectively detonating the primer charge, in which the housing is capable of disassembly and reassembly to enable the cartridges to be replaced after use.