Ammunition and explosives – Cartridges – Projectile structure
Reexamination Certificate
1999-10-28
2001-10-02
Jordan, Charles T. (Department: 3644)
Ammunition and explosives
Cartridges
Projectile structure
C102S444000, C102S501000, C102S502000, C102S529000
Reexamination Certificate
active
06295933
ABSTRACT:
The present invention relates to the general field of firearms.
It relates to a novel non-lethal projectile for firearm cartridges, in particular for handguns, used at short range and intended to neutralize or immobilize an animal, an attacker or a hostile person without endangering his life, for the purpose of maintaining order or of self-defense.
The present invention also relates to a process for obtaining such a projectile and to novel, soft and elastic, composite materials which can be used to form such a projectile.
The use, with the abovementioned goal, of plastic bullets has been known for a long time but they turn out to be too hard and often cause serious physical injuries with significant after-effects, sometimes even fatal after-effects, which is not desired when weapons of this type are used.
The use is also known of deformable projectiles made of rubber or of elastomer comprising a filler, in particular of thermoplastic elastomer of EPDM (ethylene-propylene-diene monomers), styrene-isoprene-styrene or styrene-butadiene-styrene type.
Patent Application GB 2,192,258 discloses, for example, a non-lethal round comprising a projectile made of synthetic polyisoprene.
Patent Application FR 2,532,742 discloses projectiles formed of a rubber bullet having a Shore A hardness of 40 to 55 and a diameter less than that of the bore of the barrel of the gun. This document teaches that it is essential to thus restrict the diameter of the bullet in order not to risk bursting or bulging the barrel of the gun. It also teaches that the range of hardness mentioned results from a compromise. The projectile must be sufficiently hard so as not to flatten out to an excessive degree inside the barrel, which would cause it to bulge or to burst, and the projectile must be sufficiently soft to neutralize the individual without seriously injuring him.
However, it turns out that, under certain conditions of use, in particular in close defense weapons, that is to say for short ranges, for example of less than 5 m, between the weapon and the target, the abovementioned projectiles known to a person skilled in the art are too hard and do not flatten out sufficiently on impact, which can here again result in serious injuries which can be fatal.
A person skilled in the art is therefore searching for novel elastomeric projectiles which do not have the abovementioned drawbacks and which do not result in any risk of serious injury to a living target when they are used in a close defense weapon, while ensuring the neutralization of the target for a sufficient period of time.
The present invention makes it possible to solve this problem.
A particular subject-matter of the invention is novel non-lethal projectiles for firearms having the desired abovementioned characteristics and furthermore exhibiting many other advantages.
The novel projectiles according to the invention are particularly soft, since they exhibit a Shore A hardness of between 2 and 30. They flatten out on the living target with the formation of a pancake, ensuring his temporary neutralization as a result of the shock created on impact but without inflicting serious injuries, even when fired at short range.
Furthermore, by virtue of the use of a novel, very specific, composite material in preparing the novel projectiles according to the invention, these projectiles have mechanical properties such:
that they do not result in any damage to the barrel of the gun, despite their very low hardness, even when they are used in the form of balls having a diameter identical to or greater than the diameter of the bore of the barrel, which runs counter to the teaching of the abovementioned state of the art,
that they remain physically intact and retain their mechanical properties (low hardness, elasticity) until impact on the target and even during impact,
that they can be used in cartridges devoid of wadding, by themselves ensuring leaktightness with respect to combustion gases from the propellent powder. In this particularly simple and economic configuration, the projectiles have a diameter equal to or greater than the diameter of the cartridge into which they can be forcibly inserted,
that they possess an exceptional shape memory much better than that of the projectiles known until now. Projectiles according to the invention in the form of balls with a diameter of 13 mm, forcibly inserted into cartridges with a diameter of 9.6 mm and thus retained under stress at ambient temperature, return fully to their original spherical shape when they are released and their mechanical properties have remained intact.
The novel non-lethal projectiles for firearms according to the invention are composed of a soft and elastic composite material comprising a polymeric organic matrix and a pulverulent metallic filler dispersed in the polymeric matrix.
They are characterized in that:
the Shore A hardness of the composite material, determined according to the method well known to a person skilled in the art, is between 2 and 30, preferably between 10 and 25,
the relative density of the composite material is between 1.0 and 2.9, preferably between 1.5 and 2.5,
the relative density of the metallic filler is between 4 and 22,
the polymeric organic matrix is a crosslinked polybutadiene comprising polybutadiene chains, that is to say chains with the general structure &Parenopenst;C
4
H
6
&Parenclosest;
x
, x being an integer, which are connected by bridges, -he number-average molecular mass (Mn) of the polybutadiene chains being between 500 and 10,000, preferably between 1000 and 5000.
The crosslinked polybutadiene is preferably composed solely of polybutadiene chains which are connected by bridges.
All the ranges of values mentioned above, as well as those which will follow, should be understood as including the limits.
“Crosslinked” polybutadiene should be understood as meaning a polybutadiene with a three-dimensional structure, which polybutadiene is obtained by the establishment of bridges between polybutadiene chains &Parenopenst;C
4
H
6
&Parenclosest;
x
, generally by thermosetting of a liquid or pasty composition comprising a liquid polybutadiene comprising reactive functional ends and a crosslinking agent for this polybutadiene.
It is particularly surprising that the composite material used according to the invention, which comprises a crosslinked polymeric matrix and a fairly high level of filler, can be so soft and elastic, softer and more elastic than the majority of known filler-comprising thermoplastic polymeric materials.
These soft and elastic, crosslinked polymeric composite materials, particularly suited to the preparation of non-lethal projectiles for firearms, are novel, to our knowledge.
According to a particularly preferred alternative form of the invention, the crosslinked polybutadiene is a polyurethane, that is to say that the polybutadiene chains are connected to the bridges by urethane functional groups.
Such a crosslinked polymer can be obtained by reaction of a polybutadiene comprising hydroxyl ends with a polyisocyanate crosslinking agent.
According to another alternative form, the crosslinked polybutadiene is a poly(ester-alcohol), the polybutadiene chains of which are connected to the bridges by ester-alcohol functional groups of formula
Such a crosslinked polymer can be obtained by reaction of a polybutadiene comprising carboxyl ends with a polyepoxide crosslinking agent.
According to another alternative form, the crosslinked polybutadiene is a poly(ester-amine), the polybutadiene chains of which are connected to the bridges by ester-amine functional groups of formula
Such a crosslinked polymer can be obtained by reaction of a polybutadiene comprising carboxyl ends with a polyaziridine crosslinking agent.
According to a preferred alternative form of the invention, the crosslinked polybutadiene is plasticized. Mention may be made, as examples of plasticizers well known in the rubber industry, of dioctyl azelate, dioctyl sebacate and dioctyl phthalate.
According to another preferred alternative form of the invention, the crosslinked polyb
Dubocage Bernard
Maucourt Jacques
Bucknam and Archer
Jordan Charles T.
Smith Kimberly S
SNPE
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