Non-lethal munitions having densified materials

Abstract

A non-lethal projectile having a nose component, a driving band adjacent the nose component and a body component wherein one or more of the projectile components comprises densified materials such as elastomers and foam that incorporate a dense filler material. The dense filler material is a heavy metal powder. The body component of the projectile includes a stabilizing component such as fins, drag stabilizing tails or streamers, or rifling bands for spin stabilization.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of a non-lethal projectile of the present invention, typically used for a 12 gauge shotgun;

FIG. 2 is a perspective view of a second embodiment of a non-lethal projectile of the present invention;

FIG. 3 is a third embodiment of a non-lethal projectile of the present invention being a 40 mm projectile; and

FIG. 4 is a fourth embodiment non-lethal projectile of the present invention, also a 40 mm projectile.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a non-lethal projectile 10 of the present invention, for example, for a 12 gauge shotgun having a molded projectile body 12 having a rifling band 14 for spin stabilization of the projectile and a densified foam or polymer nose section 16. The nose section, for example could be a tungsten powder filled polyurethane. The projectile body, for example, could be a densified base such as tungsten powder filled thermoplastic elastomer (TPE). The projectile body 12 is a cylindrical body and can also be molded or machined from polycarbonate and the rifling band 12 is slightly larger in diameter than the cylindrical body. The rifling band engages rifling in the barrel of a rifled-bore shotgun or launcher and impart spin to the projectile as it travels down the barrel.

To meet projectile weight, mass property, or stability requirements, the nose, rifling band or body components can be densified using density-enhanced polymer materials. This produces components with strength and mass properties similar to the metal filler material, but with hardness and compliance properties similar to the polymer materials. The components are fabricated by calculating the required amount of filler material to produce the desired density in the finished projectile. The polymer/filler material is then compounded prior to the molding operation to assure a homogenous mold material. An example of a suitable source of tungsteri powder is a product named TECHNON, which is 99.9% pure tungsten metal powder and is sold by Tungsten Heavy Powders, Inc. of San Diego, Calif. The powder has a mean particle size in the 20-150 micron range. Other metal powders can be used as the filler material such as lead, iron or other heavy metals. The body is molded using conventional production molding techniques. The molded densified components of the present invention can be attached to each other using a suitable adhesive, such as cyanoacrylate, or the components can be molded in one piece using over-molding techniques. The dense powder additive can also be materials other than heavy metal, such as bismuth trioxide. The additive requires particulates denser than the elastomer material.

FIG. 2 illustrates a second embodiment projectile 20 having for example, a molded polyurethane finned body 22 and a densified foam nose 24. The finned body 22 has a number of fins 26 uniformly spaced around the circumference of the body. The densified foam nose 24 is produced by a process which has been developed to introduce a dense powder such a tungsten into the elastomer prior to the foaming step, so that after foaming, a much denser foam material is obtained. Due to the extremely high density of material such as tungsten, addition of a dense powder to an elastomeric foam has a dramatic effect on the material density and the resulting projectile mass. The projectile mass and delivered kinetic energy can be maximized without the use of solid metal slugs. The primary benefit of using an elastomeric foam as a projectile nose material is its compliant response when subjected to compression. This compliance allows energy dissipation upon impact with the target, minimizing the chance for serious injury. By controlling the amount of dense powder added to the elastomer prior to foaming, the compliant properties of the finished foam product can be maintained, along with the projectile lethality benefits. By using density-enhanced foam materials, the mass properties of the projectile can be adjusted without giving up desired material properties necessary for absorbing energy upon target impact.

A comparison of measured material properties for density-enhanced foam is illustrated in the following table which includes a comparison to a typical projectile foam nose material. The primary figure of merit that was used to compare the materials is a modified Indention Force Deflection (IFD, ASTM D3575) measurement, which is an industry standard for measuring the firmness of a foam sample by measuring the force required to compress the sample by 25%. The industry standard IFD measurement uses a sample that measures 15″ square by 4″ thick. Since this is not practical for measurement of a foam nose for a projectile, the test was modified to use a 1″×1″ cylindrical sample, and compared this measurement to IFD numbers for a material which was T600 olefin foam.

				In-house	ASTM
		Wt. %	Density	IFD	D3575
Sample	Description	Tungsten	(lb/ft3)	psi @ 25%	psi @ 25%
1	Tungsten/	94.84	241.9	144
	PU foam
2	Tungsten/	93.72	189.9	55
	PU foam
3	Tungsten/	92.90	117.0	22.5
	PU foam
4	PU Foam	0.00	7.62	1.25
5	Minicel	0.00	6.84	17	18
	T600

As shown in sample 5, the in-house IFD measurement yielded similar results to the ASTM test for the same -material, giving some confidence to the measurement on the density-enhanced materials.

FIG. 3 illustrates a third embodiment munition 30 having a projectile 32 positioned within an aluminum 40 mm shell case 34 and comprising a molded polycarbonate body 36 having appropriate rifling bands 38 for spin stabilization and a densified foam nose 40. For example, the foam nose could be a tungsten-filled polyolefin and the projectile body 36 could be a tungsten-filled polycarbonate. The projectile is propelled from the casing by a smokeless powder charge 42 positioned in the casing below the projectile.

FIG. 4 illustrate a fourth embodiment non-lethal munition 50 having a projectile 52 positioned within a shell casing 54 having a molded polycarbonate base 56 a densified material mid-section 58 and a rigid, crushable densified foam nose 60. For example, the nose could be made of a tungsten filled polyurethane foam having a hollow section 62 so that the nose is crushable.

One example of a propulsion system for the present invention incorporates a blank cartridge 64 and a ruptured disc 66 positioned into a high pressure chamber 68 located at one end 70 of the shell casing. The high pressure chamber 68 is connected to a low pressure chamber 72 by a vent hole 74. The projectile 52 is positioned in the low pressure chamber 72 of the shell casing.

Although the present invention has been described and illustrated with respect to four embodiments thereof, it is not to be so limited since changes and modification can be made therein which is in the full intended scope of the invention as hereinafter claimed. For example, the projectile can be molded as a single piece having a nose component and a body component or can be molded as separate components and joined together.

Claims

1. A non-lethal projectile comprising: a nose component; anda body component,wherein at least one of the nose component or the body component comprises a densified material comprising an elastomer or foam having a densified powder filler.

2. The projectile of claim 1 wherein the non-lethal projectile further comprises a driving band positioned on the body component.

3. The projectile of claim 1 further comprising means for providing aerodynamic stability of the projectile during flight.

4. The projectile of claim 3 wherein the means for providing aerodynamic stability includes at least one of a fin, tail or ribbon attached to the body component for drag stabilization.

5. The projectile of claim 1 wherein the elastomer of the nose or the body portion is at least one of a polyurethane, polyolefin, silicon rubber, polyvinyl chloride or polystyrene and the densified powder filler is a heavy metal being at least one of tungsten, lead or iron.

6. The projectile of claim 1 wherein the nose component is in elastomeric foam densified by the mixture of a heavy metal powder.

7. The projectile of claim 1 further comprising a shell casing for receipt of the base component.

8. The projectile of claim 1 wherein the projectile is to be fired from a 12 gauge launching system.

9. The projectile of claim 1 wherein the projectile is to be launched from a 37 or 40 mm gas gun.

10. The projectile of claim 1 wherein the body component is molded or machined polycarbonate.

11. The projectile of claim 5 wherein the filler has a mean particle size of about 20 to about 150 microns.

12. A less-than lethal munition comprising a projectile having a nose section and a body section wherein at least one of the nose section and the body section comprises a polymer that is densified by a powder filler to maximize kinetic energy delivered by the munition.

13. The munition of claim 12 further comprising a driving band positioned on the body section.

14. The munition of claim 12 further comprising a means for providing aerodynamic stability comprising at least one of a fin, tail, or ribbon attached to the body section of the munition for drag stabilization.

15. The munition of claim 12 wherein the polymer is selected from the group including polyurethane, polyolefin, silicon rubber, polyvinyl chloride or polystyrene.

16. The munition of claim 12 wherein the nose section is a foam polymer.

17. A method of manufacturing a non-lethal projectile comprising the steps of: selecting a desired elastomer material for the projectile;calculating a required amount of filler material for a desired density of the projectile;compounding the selected elastomer material and the calculated filler material; andmolding the compounded elastomer and filler materials into the projectile.

18. The method of claim 17 further comprising molding a nose component and a body component of the projectile.

19. The method of claim 18 further comprising the step of joining the nose component and the body component by an adhesive or by over molding.

20. The method of claim 18 wherein the step for molding the nose component is by foaming.