Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
  • F41A1/00—Missile propulsion characterised by the use of explosive or combustible propellant charges
  • F41A1/08—Recoilless guns, i.e. guns having propulsion means producing no recoil
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C13/00—Details of vessels or of the filling or discharging of vessels
  • F17C13/06—Closures, e.g. cap, breakable member

Definitions

• This invention relates to a bottom plate member which is designed and made for initially tightening a chamber in which a high gas pressure is generated. Examples of such chambers can be found in ammunition rounds for recoilless weapons but also in pipes and containers within the pro ⁇ cess industry.
• the invention relates to a bottom plate member which is located at the rear end of a propellant charge chamber of an ammunition round for a re ⁇ coilless weapon. Initially the bottom plate member pro ⁇ vides a tightening and barrier for the propellant gases, for instance gases of powder, generated in the chamber when the round is fired, but is broken when the gas pres- sure within the chamber exceeds a certain level so that the gases are allowed to exit from the rear end of the am ⁇ munition round.
• the propellant gases for instance gases of powder
• Bottom plate members of this type have previously been used in ammunition rounds for recoilless weapon systems. It is the gas outlet rearwards, when the rear bottom plate is broken, that makes the weapon recoilless. It is also previously known to use similar bottom plates as so-called blasting foils in the process industry, in which the func- tion of the bottom plate is to break and evacuate the gas ⁇ es as soon as an inadmissible gas pressure is generated in a pipe or a container.
• the object of this invention is to solve the problems that have been discussed above and provide a more controlled and splinterfree process for the opening of the plate so that a substantially 100% safety is achieved for this pro ⁇ cess.
• this is achieved by pro ⁇ viding the bottom plate with a through hole in the center which gives an effective starting point for the cracking process, fractural impressions for controlling the crack ⁇ ing process so that the plate after the cracking start is divided into a number of well defined flaps, but which are connected to each other, and a number of straight edges, which number corresponds to the number of flaps, against which edges the base of the flaps are arranged to be fold ⁇ ed when the plate is opened up due to the gas pressure.
• FIG. 1 shows a complete ammunition round for a recoilless weapon system before firing as well as after firing
• fig ⁇ ure 3 shows the bottom plate with the fractural impres ⁇ sions more in detail
• figure 4 shows an insert member for the bottom plate
• figure 5 shows the two members bottom plate and insert member put together.
• Figure 1 shows a complete ammunition round 1 in firing po ⁇ sition in a launching barrel 2 of a recoilless weapon sys- tern, for example a 20 mm ammunition round.
• the launching barrel 2 has a rear conventional nozzle 3 for the exhaust ⁇ ing propellant gases.
• the ammunition round 1 comprises a chamber 4 with a propellant charge therein and a detonator 5.
• a bottom plate 6 is located at the rear end of the chamber 4 for tightening the chamber and providing a bar ⁇ rier for the generated powder gases so that an efficient ignition over the propellant charge is guaranteed.
• the bottom plate consists basically of a comparatively thin, circular disc 7 and a flange 8 arranged at the rearmost part of the chamber wall 9.
• the bottom plate 6 is dimensioned so that it is broken and blown open by the gases as soon as a specific gas pressure has been reached within the chamber. It is this gas pres ⁇ sure that makes the weapon recoilless.
• the plate member has been designed and made in such a way that basically 100% safety against such small and harmful fragments is guaranteed when the plate member is opened up by the gas pressure.
• the design of the bottom plate is illustrated more in de- tail in figure 3 by means of a front view as well as a cross-section.
• the circular disc part 7 of the plate member has a star fracture so that six flaps 11 are formed.
• the star-shaped fractural impression is made by means of material-reducing notches in the plate, in this case six symmetrically arranged notches 10.
• the notches are not extending all the way to the periphery of the plate, but end up at a certain dis ⁇ tance d from the edge of the plate so that an integral, annular part with no material reductions is remained.
• the center of the plate has a through hole 12.
• the hole is small compared to the di ⁇ mension of the plate, specifically the diameter of the hole is approximately 10% of the plate diameter.
• this hole 12 is a through hole and located in the center of the plate it provides an efficient starting point for the cracking process. With fractural impressions 10 alone, it has turned out that small fragments are broken away from the central portion of the plate 6 which fragments might be harmful for personnel and/or equipment. By introducing the through hole in the center of the plate the risk for such undesired fragments is substantially reduced, the central portion of the plate which otherwise might give rise to said loose fragments is simply removed from the beginning.
• the through hole in the plate has also another purpose.
• a high-amplitude pressure peak is obtained which might give rise to a pen ⁇ dulum pressure in the chamber.
• the hole 12 in the plate has a damping ability with respect to such pressure peak and reduces the risk of dangerous pendulum-type pressure.
• Figure 2 illustrates the ammunition round 1 after firing with the now empty propellant charge chamber and the opened bottom plate 6.
• the flaps 11 of the plate have been bent backwards and bear against the inner wall of the noz ⁇ zle with their tips.
• the bottom plate member comprises a ring-shaped insert member 14, see figure 4, which insert member abuts the flange 8 of the bottom plate with its outer, circumfe ⁇ rential surface 15 and which has a hexagonal inner part, i e six straight edges 16 against which the base portions of the flaps are bent.
• the bottom plate itself according to figure 3 is prefer ⁇ ably made of a ductile stainless steel material.
• the in ⁇ sert member 14 for the plate, see figure 4 is preferably made of a sintered stainless steel material or made from a rod-shaped material which is finish-turned on its outer surface and then cut off in suitable lengths.
• the bottom plate also could be made as a unitary member, in which case the straight edges 16 against which the flaps are bent are made directly in the flange 8 of the bottom plate itself.
• the fractional impression is made as a star- shaped pattern so that six flaps are formed when the bot ⁇ tom plate is blown up.
• any other pattern formed by the fractional impressions can be used so that the num ⁇ ber of flaps can be varied.
• the insert member 14 is made with a number of straight edges, which number corre ⁇ sponds to the number of flaps, which means that each flap has a straight edge to be bent around upon the release of gas pressure.
• the hole 12 has been illustrated as a through hole, but it is understood that the hole can be sealed by means of a foil or the like to make the chamber damp-proof, especial ⁇ ly during transport and storage. Such a thin sealing mem ⁇ ber does not change the described function of the hole 12, however.
• the invention has been described in connection with a pro ⁇ pellant charge chamber for a recoilless weapon system. It should be understood that the bottom plate can be used al ⁇ so in other applications in which a controlled opening of a plate is required when a certain pressure has been ex ⁇ ceeded. Examples of such applications can be found in the process industry.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Containers And Packaging Bodies Having A Special Means To Remove Contents (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)
• Rigid Containers With Two Or More Constituent Elements (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20397927

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (6)

Citations (4)

Family Cites Families (5)

• 1995
  • 1995-04-11 SE SE9501344A patent/SE506253C2/sv not_active IP Right Cessation
• 1996
  • 1996-04-10 CA CA002217528A patent/CA2217528C/en not_active Expired - Fee Related
  • 1996-04-10 EP EP96910281A patent/EP0870165B1/en not_active Expired - Lifetime
  • 1996-04-10 DE DE69622586T patent/DE69622586D1/de not_active Expired - Lifetime
  • 1996-04-10 US US08/930,591 patent/US5900575A/en not_active Expired - Fee Related
  • 1996-04-10 WO PCT/SE1996/000469 patent/WO1996032610A1/en active IP Right Grant

Patent Citations (4)

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