The present invention relates to a projectile used for incapacitation of a human being or animal target and more specifically mechanisms for absorbing kinetic energy of the non-lethal projectile.
Conventional weapons are used by law enforcement personnel to deter and subdue criminals. However, the use of conventional weapons by the law enforcement personnel is limited by the possibility of inflicting injury to an alleged suspect, since the courts and not law enforcement personnel have the responsibility for determining guilt and sentencing a criminal. Even worse the use of conventional weapons by law enforcement personnel may lead to a tragic injury or death of an innocent bystander. Furthermore, non-lethal weapons are required for controlling crowds in violent demonstrations.
A non-lethal weapons system is used to incapacitate as opposed to inflict injury in order to prevent suspect targets from fleeing, engaging in further combat, or committing other criminal acts. Conventional non-lethal weapons include billy clubs (or batons) rubber and plastic bullets. Batons as used by the law enforcement officers are wielded in close range and are capable of inflicting serious physical trauma. Rubber and plastic bullets are typically too energetic to be used at distances less than about 25 meters and become ineffective at distances greater than 50 meters. Conventional rubber and plastic bullets have caused a significant number of unwanted injuries.
U.S. Pat. No. 3,710,720 discloses a weapon system including a launcher and a flexible low lethality projectile of relatively large mass adapted to be radially expanded during trajectory so as to present a relatively large impact surface to the target. The projectile has an initial relatively small cross section so as to be insertable in a conventional launcher. The launcher has internal rifling grooves within the barrel to effect rotation of the projectile and radial expansion thereof due to centrifugal force. The relatively large area of contact on impact reduces energy per unit area penetration of the target while maintaining high inertia energy.
U.S. Pat. No. 6,012,295 discloses a baton projectile including a case of low density polyethylene, and a core of a soft material such as a thermoplastic gel modified rubber. At higher than acceptable impact forces, the case ruptures and the core spreads out to radially disperse the excess impact energy and to present a larger impact area to the target so that the risk of unacceptable penetration and trauma injury to the target is reduced.
The term “target” as used herein refer to the person or animal being incapacitated. The term “outward” as used herein referring to a non-lethal projectile includes a direction with a significant radial component pointing away from the longitudinal axis of the projectile.
The term “viscoelasticity” as used herein describes materials that exhibit both viscous and elastic characteristics when undergoing deformation.
The term “energy density” as used herein refers to a kinetic energy impact of a projectile on a target and is defined as the kinetic energy of the projectile divided by the area of the impact, typically given in units of area per square centimeter.
The term “pressure” as used herein refers to the force of impact of a projectile on a target divided by the area of the impact.
According to an aspect of the present invention, a projectile is provided for use in a non-lethal weapon system. The projectile includes a main body with a longitudinal axis and a deformable head attached to the main body. The projectile having a certain kinetic energy is launched along the longitudinal axis in the direction of a target. Upon impact of the projectile with the target, the deformable head deforms viscoelastically. A part of the kinetic energy of the projectile is viscously dissipated and another part of the kinetic energy is absorbed elastically so that the remaining kinetic energy of the projectile on impact with the target is reduced to a non-lethal level. The projectile preferably includes a semi-rigid element. which includes two or more segments connected by foldable portions. The semi-rigid element preferably supports at least in part the deformable head and attaches to the main body. An air gap and/or soft material is preferably disposed between the semi-rigid element and the main body and/or between the semi-rigid element and the deformable head. Upon impact of the projectile with the target, one or more of the foldable portions bends outward or moves outward in response to the impact. One or more separators are preferably embedded into the deformable head. The separators are preferably transversely oriented, substantially perpendicular to the longitudinal axis. Alternatively, multiple longitudinal members are embedded within the deformable head pointing towards the target and substantially parallel to the longitudinal axis. Upon impact, the longitudinal members are bent outward away from the longitudinal axis. The bending outward by the longitudinal members preferably assists in holding the projectile to the target. The longitudinal members optionally include at least one barbed end which pierce and/or attach to the target upon impact. The deformable head is preferably formed at least in part from a silicone rubber polymer raw material without added cross linking agents or other additives. The projectile preferably includes a second body with the same longitudinal axis. The second body includes a hollow. The first body fits marginally within the hollow so that during the impact the first body is forced into the hollow, deforming at least one of the first body or the second body and thereby absorbing another portion of the kinetic energy. The projectile preferably includes an elastic mechanism which on impact absorbs elastically a portion of the kinetic energy which is stored elastically as stored energy within said elastic mechanism. After the initial impact with the target, the elastic mechanism optionally releases the stored energy to the target thus extending the impulse duration at a lower force.
According to another aspect of the present invention, a projectile is provided for use in a non-lethal weapon system. The projectile includes a first body with a longitudinal axis. The projectile having kinetic energy is launched substantially along the longitudinal axis in the direction of a target. Upon impact of the projectile with the target an elastic mechanism absorbs elastically a first portion of the kinetic energy. The elastic mechanism preferably reduces the maximum force that the projectile exerts on the target during the impact. The elastic mechanism initially during the impact absorbs elastically a second portion of the kinetic energy which is stored elastically as stored energy within the elastic mechanism. After the initial impact with the target the elastic mechanism releases the stored energy to the target thus extending the duration of the impulse but at a lower force. Alternatively, a locking mechanism stores the first portion of the kinetic energy within the elastic mechanism; whereby the remaining kinetic energy of the impact is reduced to a non-lethal level of the target. The projectile preferably includes a deformable head attached to the first body. The deformable head is formed from a viscoelastic material which manifests both the elastic mechanism (with the elastic mechanical properties of the viscoelastic material) and further manifests the locking mechanism with the viscous properties of the viscoelastic material. The elastic mechanism preferably includes a spring which is deformed upon the impact, and stores elastically the first portion of the kinetic energy. This stored energy can be optionally delivered later to the target by releasing the locking mechanism. Alternatively or in addition, the projectile preferably includes a second body with the same longitudinal axis and a hollow. A portion of the first body fits marginally within the hollow. The elastic mechanism includes an elastic deformation of the first body and/or second body while the first body is forced into the hollow during the impact. The first body is preferably externally ridged with first ridges and the hollow is internally ridged with matching second ridges. While the first body is forced into the hollow during the impact, the locking mechanism includes locking the first ridges on the second ridges. The first ridges and second ridges are preferably shaped to prevent release of the elastic mechanism. Alternatively, the locking mechanism is performed using a frictional mechanism which dissipates another portion of the kinetic energy as energy of kinetic friction between the first body and the second body.
According to still another aspect of the present invention, there is provided a projectile including the main body, the deformable head which deforms viscoelastically, the semi-rigid element including at least two segments connected by at least one foldable portion thereof and supports at least in part the deformable head and the second body which during the impact the first body is forced into the hollow of the second body, deforming at least one of the first body or the second body and thereby absorbing a portion of the kinetic energy.
The foregoing and/or other aspects will become apparent from the following detailed description when considered in conjunction with the accompanying drawing figures.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
Before explaining embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of design and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
By way of introduction, embodiments of the present invention are applicable to projectiles fired at high speed, for example by standard weaponry, e.g. rifle, which carry sufficient kinetic energy to inflict trauma or kill. Projectiles are launched at high speed or high kinetic energy in order to achieve accuracy and range. Absorption of the energy on or just prior to impact according to aspects of the present invention to provide an accurate and non-lethal projectile. Moreover, different embodiments of the present invention may be applied independent of the method of incapacitation used. The incapacitation may be inflicted by different methods including the impact of the projectile and/or by other known methods such as electric shock or administration of drugs, e.g. by needle, or through the air to skin, eyes, and/or respiratory membranes of the target.
Referring now to the drawings,
A non-limiting list of examples of base materials which may be used for deformable head 13 includes: silicones; fluorosilicones; polyurethanes; polysulfides; polybutylenes (polymers based on C4 monomers); polyvinyl chloride; acrylic resins; vinyl acetate; ethylene vinyl acetate; vinyl acrylic (copolymers of vinyl acetate and alkyl acrylates such as butyl acrylate); styrene butadiene rubber (SBR); styrenic block copolymers; oleoresinous compositions; bituminous; rosin; unsaturated elastomers such as polybutadiene, polyisoprene and polychloroprene; saturated elastomers such as polyisobutylene, ethylene propylenediene monomer rubber (EPDM), ethylene-propylene copolymers (EPR—Ethylene Propylene rubber), nitrile-butadiene rubber, and polybutene; and mineral clays and synthetic clays. Mixture of the above mentioned materials or additives thereto such as powders, colloidal silica, fibers may be used to adjust the mechanical properties, e.g. increase the shear force on impact or increase material shelf life, of the deformable material as is known in the art of materials science. The deformable material is optionally constructed of two or more layers made of different materials with different characteristics of deformability to achieve a specific behavior of deformation. The deformable material is optionally coated to protect the deformable material from environmental conditions or excessive forces during firing or ballistic travel.
In preferred embodiments of the present invention, the material of deformable head 13 is viscoelastic and responds both viscously like putty and elastically like rubber
The viscous deformation causes some of the kinetic energy of the impact to be dissipated and the elastic deformation allows some of the kinetic energy to be stored elastically in the material. The percentage of the elastic energy in the material depends on the material selected. If it is desired to reduce the bounce of the projectile from the target, elastic energy can be reduced for example to a few percent of the kinetic energy of the projectile.
A preferred raw material used for the deformable head is Bayer Siloprene HV1/401. The material is preferably used not according to manufacturers instructions but without any cross linking agents or other additives. A method for making putty like elastic organo-silicon compositions, which retains shape for an extended period of time, is described in U.S. Pat. No. 3,350,344.
It should be noted the shape that the shape of deformable head 13 can be, by non-limiting example, conical, spheroid, cylindroid, ellipsoid, or aspheric.
Reference is now made to
The magnitude of the shear forces depends on the thickness of the shear layer. Reducing the thickness of the material layer increases the shear forces. Therefore, as illustrated in
Reference is now made to
Reference is now made to
Reference is now made to
When projectile 50 hits target 11 there is contact between target 11 and deformable head 13. As the middle segment is forced by the pressure to moves toward main body 15, the outer segments unfold with an outward motion. As a result, the cross sectional area of projectile 50 is increased on impact and the area cross-sectional area of the deformed material of deformable head 13.
Semi-rigid support element 43 or 53 in different embodiments preferably folds elastically and/or plastically or a combination of both elastic and plastic deformation.
Reference is now made to
Reference is now made to
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The foregoing discussion of various embodiments of the present invention is illustrative only. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
Although embodiments of the present invention have been shown and described, it is to be appreciated that variations, modifications, and other applications may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
The present application claims the benefit of U.S. provisional application 60/909,461 filed on Apr. 1, 2007, by the present Applicants, the disclosure of which is included herein by reference.
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