Patent Publication Number: US-6701848-B1

Title: Anti-personnel canister

Description:
FEDERAL RESEARCH STATEMENT 
     [The inventions described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes.] 
     BACKGROUND OF INVENTION 
     The invention relates in general to anti-personnel (APERS) munitions and in particular to a gun launched anti-personnel munition. 
     U.S. Pat. No. 3,956,990 incorporates a payload of layers of flechettes. However, this design requires an internal charge and a plurality of detonator systems to disperse the payload. This is a costly and complicated design thereby allowing for higher probability of failure. 
     U.S. Pat. No. 4,301,737 is a dual purpose APERS round. In addition to the anti-personnel capability, it also uses an armor piercing anti-tank penetrator core. This round is not practical in the event there is no tank target. It is also less effective because there is a reduced anti-personnel payload. This also increases the costs considerably. 
     U.S. Pat. No. 4,494,459 is also a dual purpose APERS round. However, unlike U.S. Pat. No. 4,301,737, this design uses a high explosive, armor piercing charge instead of the penetrator core. These both lack practicality due to the need of an armored target. This design is even more costly because there is an aft charge for the anti-personnel shrapnel. 
     U.S. Pat. No. 4,515,083, while called “anti-personnel,” is not a gun fired ammunition. It is actually a hand-launched grenade. This contains an explosive, which turns the casing into shrapnel. 
     U.S. Pat. No. 4,580,500 is another dual purpose round. This design differs from the previous dual-purpose rounds in that both the anti-tank and the anti-personnel payload are mines. This design is not intended for the elimination of current personnel. 
     U.S. Pat. No. 4,583,461 is a canister with a payload of mini-bombs. The small bombs are ejected by the use of a charge (an ignitable propellant). The small bombs are deployed when the case reaches a specific height above the ground. This design is more suitable for a longer range. 
     A dual purpose round is disclosed, wherein the anti-tank portion is a high explosive charge, but the anti-personnel portion uses the fragmentation of the casing as the projectiles. This round is not desirable due to the duality of the design. It also has less effectiveness toward the anti-personnel portion due to the lack of payload. 
     A fragmentation projectile such as a single or dual purpose grenade or bomblet for a cargo projectile, is disclosed, wherein a fragmentation body the envelopes an explosive charge carrying casing, which fragmentation body comprises one or more fragmentation rings notched in axial direction. 
     U.S. Pat. No. 5,225,628 is specifically an anti-personnel round. This design utilizes a non-elastic collision projectile, which increases the effectiveness of each impact. However, this design has two major drawbacks. The first is that the canister must have an open end, which does not provide containment of the “Lead Wax Pellets”. It also has temperature restrictions. This also requires an indicator that increases the cost. 
     U.S. Pat. No. 5,866,841 is a fragmentation grenade. Though its effective principle is similar the method of function is vastly different; requiring high explosive to provide the energy to the high speed fragments. 
     U.S. Pat. No. 5,936,183 is an anti-personnel area denial device. It is not a round and functions like a mine using a TASER electronic stun method to provide a temporary non-lethal effect. This device has a completely different operating principle and effective range. 
     SUMMARY OF INVENTION 
     One embodiment of the present invention is an anti-personnel canister comprising a generally cylindrical container having side walls, the side walls defining an enclosure with a generally concave surface at one end and an opening at another end; the side walls having an outer surface, the outer surface including a plurality of longitudinal grooves formed therein and, below the plurality of longitudinal grooves, a circumferential obturator groove; a plurality of submunitions disposed in the enclosure; a spacer disposed in the enclosure between the plurality of submunitions and the opening; and a cap disposed on the opening of the container, the cap having a top surface and including a pair of orthogonal grooves formed on the top surface. 
    
    
     The invention will be better understood, and further objects, features, and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings. Brief 
     DESCRIPTION OF DRAWINGS 
     In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals. 
     FIG. 1 is a perspective view of a gun fired round incorporating the APERS canister of the present invention. 
     FIG. 2 is a sectional view of the canister of the present invention. 
     FIGS. 3A,  3 B and  3 C show various submunitions that fill the canister. 
     FIG. 4 is the sectional view of FIG. 2, without cross-hatching. 
     FIG. 5A is a sectional view of a slip ring and FIG. 5B is a sectional view of an obturator. 
     FIG. 6 is a top view of the cap for the canister. 
     FIG. 7 is a sectional view of the cap of FIG.  6 . 
    
    
     DETAILED DESCRIPTION 
     The APERS canister of the instant invention is a gun launched ammunition (round). It may be fired from, for example, a tank or artillery piece. The canister is designed for defeating groups of personnel at various ranges, as opposed to defeating tanks, armored personnel carriers, aircraft, or other vehicle targets. The goal of this type of ammunition, much like a shotgun, is to disperse the payload upon exiting the gun tube and achieve maximum dispersion thus eliminating the maximum number of enemy personnel. The payload may comprise round tungsten balls, steel rectangular prisms, or flechettes. 
     The effective range of the 105 mm canister is out to 500 meters. It is large enough to carry a payload capable of incapacitating an advanced squad of 10 men wearing winter gear. The cartridge is fired from standard United States Government military equipment with rifling typically used for firing 105 mm ammunition. The 105 mm canister has a plastic slip band in order to control the spinning of the projectile. There is no fuze on this round. In a preferred embodiment, the canister contains approximately 800-1000 tungsten balls, which are expelled upon muzzle exit. 
     FIG. 1 is a perspective view of a gun fired round incorporating the APERS canister  10  of the present invention. Canister  10  sits on cartridge  12 . Cartridge  12 , as is known in the art, is a combustible cartridge case loaded with propellant. An electric primer is fitted in the center of the propellant which when fired provides a flash and the gasses necessary to ignite the propellant. The burning propellant provides the gasses needed to force the canister  10  from the gun tube. 
     FIG. 2 is a sectional view of the canister  10  of the present invention. FIG. 4 is the sectional view of FIG. 2, without cross-hatching. Canister  10  comprises a generally cylindrical container  14  having side walls  16 . The side walls  16  define an enclosure  18  with a generally concave surface  20  at one end and an opening  22  at another end. The outer surface of side walls  16  (see FIG. 4) include a plurality of longitudinal grooves  24  formed therein. Preferably, the plurality of longitudinal grooves  24  are equally spaced around the circumference of side walls  16 . In a preferred embodiment, the number of longitudinal grooves  24  is four. Canister  10  is preferably made of steel. 
     Below the plurality of longitudinal grooves  24  is a circumferential obturator groove  26 . FIG. 5A is a sectional view of a slip band  44  and FIG. 5B is a sectional view of an obturator  42 . Obturator  42  is disposed in the obturator groove  26 . Plastic slip band  44  is disposed in the obturator groove  26  beneath the obturator  42 . Slip band  44  reduces the spin imparted to canister  10  by rifling in the gun tube. A circumferential cartridge attachment groove  52  is disposed below the obturator groove  26  for attaching the container  14  to a cartridge case  12 . In a preferred embodiment, the cartridge case is a 105 mm cartridge case. 
     A plurality of submunitions are disposed in the enclosure  18 , extending from the concave surface  20  to a spacer  30  disposed in the enclosure  18  between the plurality of submunitions and the opening  22 . As shown in FIGS. 3A,  3 B and  3 C, the submunitions comprise one of balls  36 , rectangular prisms  38  and flechettes  40 . Rectangular prisms  38  may be made of steel. Preferably, the submunitons are balls  36  made of tungsten. The number of tungsten balls  36  is in the range of about 800 to about 1000. 
     FIG. 6 is a top view of the cap  32  for the container  14 . FIG. 7 is a sectional view of the cap of FIG.  6 . The cap  32  is disposed on the opening  22  of the container  14 . The cap  32  includes a pair of orthogonal grooves  34  formed on the top surface thereof. Cap  32  is preferably made out of aluminum and holds the payload of submunitions in place. As best seen in FIG. 7, a bottom surface of the cap  32  includes a reduced thickness concave portion  46 . Cap  32  includes external threads  48  that mate with internal threads  50  on the inner surface of the side walls  16 . 
     In one embodiment, the thickness of the cap  32  at the concave portion  46  is about 0.225 inches, the depth of the pair of orthogonal grooves  34  is about 0.15 inches and the width of the pair of orthogonal grooves  34  is about 0.16 inches. In addition, the width of the longitudinal grooves  24  is about 0.065 inches, the depth of the longitudinal grooves  24  is about 0.055 inches, the outside diameter of the container  14  is about 4.128 inches and the thickness of the side walls is about 0.239 inches. 
     When canister  10  exits the gun tube, air pressure bears on the two orthogonal grooves  34  (stress channels) in the cap  32 . The air pressure, coupled with the four longitudinal stress grooves  24  on the side walls  16  and the centrifugal force caused by the rifled spinning, breaks the canister  10  apart, thereby deploying the submunitions contained therein. 
     While the invention has been described with reference to certain preferred embodiments, numerous changes, alterations and modifications to the described embodiments are possible without departing from the spirit and scope of the invention as defined in the appended claims, and equivalents thereof.