Abstract:
The instant invention discloses a triboluminescent projectile useful for identifying a point of impact and includes one or more triboluminescent materials contained thereon or therein. The projectile is in the form of any shape or size and is constructed and arranged to be combined with at least one triboluminescent material. Mechanical stress inducing materials may be included with the triboluminescent materials. The projectile, in combination with the triboluminescent materials, provides a user with identification of the target-projectile point of impact.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to projectiles which contain luminescent material and more specifically to projectiles containing triboluminescent material which emit light upon impact. 
       BACKGROUND OF THE INVENTION 
       [0002]    Weapons have a wide range of applications. Militaries use weapons to protect national interests. Law enforcement agencies use weapons to protect its agents while pursuing its enforcement objectives. Individuals use weapons for personal protection, hunting and/or sporting activities. Any use of a weapon generally necessitates methods for ensuring that the projectiles fired from the weapon contacts the intended target. Determining the point of impact provides accuracy to assist in training and reducing the risks associated with impacting unintended targets. 
         [0003]    Ensuring that a projectile fired from a weapon strikes the intended target depends on several related factors, including conditions during use and the user&#39;s skill, knowledge and training. In order to minimize hitting unintended targets, it is not uncommon for military and law enforcement personnel to undergo intense training aimed at improving a user&#39;s accuracy and ability to strike an intended target. Moreover, in order to maximize the benefits of a training program, it is vital that adjustments are made under real-life situations. In order to accomplish these goals, it is imperative to determine where the projectiles actually strike a target. The effectiveness of the weapon can be tested as well, providing opportunities to provide needed calibrations or adjustments. In situations where the intended target is missed or for operations during limited visibility, i.e. night time covert operations, the user would have the ability to make the appropriate site adjustments. 
         [0004]    Several techniques have been utilized which aid a user in detecting points of impact with a target, including projectiles modified to include materials which can be ignited, burned or exploded to produce light, smoke, or combinations. Typical tracer ammunition includes bullets which have been modified to contain pyrotechnic agents. The pyrotechnic agents are ignited upon firing and burn very brightly, providing visible confirmation and tracking of the bullet as it is fired along its trajectory. The advantage of using tracer ammunition allows the shooter to visually track the projectile path as it makes its way to the intended target. Such visualization allows the trajectory of the fired projectile to be determined, with corrections relative to the intended target made based upon visual tracking of the projectile. Additionally, tracers may be used by a shooter to mark a target, providing others nearby a visual confirmation as to an intended target for which they should further shoot. 
         [0005]    Therefore, what is needed is a projectile, defined as a shell, bullet, munitions, ammunition, or the like which incorporates luminescent materials capable of emitting light upon impact with a target and which overcome the disadvantages associated with other methods for detecting projectile points of impact. 
       DESCRIPTION OF THE PRIOR ART 
       [0006]    Various devices are known in the prior art that use pyrotechnics to illuminate, signal, or generate smoke which in turn may be useful for determining projectile point of impact with a target. U.S. Pat. No. 4,301,732 discloses a tracer bullet which is modified to include a magnesium element. The magnesium element extends downwardly from the projectile element or slug, and into the shell of an assembled cartridge. The lower portion of the magnesium element contains a pyrotechnic material which is held in close proximity to the charge of powder in the shell. The explosion of the charge ignites the pyrotechnic while it discharges the projectile. The pyrotechnic, in turn, ignites the magnesium element. Openings are provided in the magnesium element to ensure that the bright light created by the burning of these elements can be seen from the side such as by a surveyor sighting through a theodolite at a remote point. As a result, the projectile leaves a highly visible trail. 
         [0007]    U.S. Pat. No. 5,661,257 discloses a covert multispectral day/night target marker which does not emit visible light. The marker emits a signature detectable in the electromagnetic spectrum including visible, near infrared, middle and longwave infrared, and radar regions. The marker is particularly useful for marking of target areas so that they can be easily detected from the ground or the air. The visible spectrum is marked by a white or colored pyrotechnic smoke generant. The near infrared region is marked by near infrared emitting photodiodes encased in a hardened polymeric molding compound. These diodes are only visible through night vision devices. The middle through the far infrared regions are marked by the heat generated from the combustion of the pyrotechnic smoke generant. The smoke generant is housed in a canister having a highly emissive surface. The radar region is marked using radar chaff. The target marker is configured for use with conventional mortar or rocket delivered flare systems. A hand held, rocket-propelled parachute signal is disclosed which includes near infrared emitting photodiodes and oscillator electronics assembly encased in a hardened polymeric molding compound launched from a hand-fired expendable-type launcher. 
         [0008]    Other devices are known which produce light that are non-incendiary. U.S. Pat. No. 6,990,905 discloses a non-lethal marker projectile that provides site identification capability of a target upon impact with the target. The projectile includes a generally cylindrical rear base made of a resilient material and a front end made of plastic or composite extending longitudinally from the rear base. The front end includes an outer surface having a rear portion which is attached to the rear base and a nose portion serving as a windshield. The front end also includes a breakable container system located in the space which contains separated chemiluminescent reagents which when mixed produce light. The front end further includes a foam filler surrounding the breakable container system and which fills the space. In addition, an optional plastic donut containing either chemlucent chemical (peroxide or oxalate liquid) or air to cushion impact with objects may be placed in the front end with the foam filler. With this projectile construction, the container system breaks on a setback impact that is exerted during firing and initial launch, causing the chemiluminescent reagents to mix and be absorbed into the foam filler such that upon impact of the projectile with the target, the foam filler marks the target with the mixed chemiluminescent reagents diffused therein. 
         [0009]    U.S. Pat. No. 5,018,540 discloses a luminescent paintball having easily ruptured paintball type projectiles that are fired from compressed air guns. The invention provides for a double chamber projectile capsule that contains two chemical agents which, when mixed together on impact, provide a luminescent spot to visibly mark impacts at night. The modified paintball projectile is designed to fit into the present standardized paintball specifications, without adding unusual expense. 
         [0010]    U.S. Pat. No. 3,940,605 describes a chemiluminescent lighting apparatus for generating an illuminated marker material for delivery to a desired area. Two fluids to be mixed are contained in separate chambers and are separated from a mixing chamber by means of frangible disc-shaped members. A hollow gas generator expels gas when a squib fractures one of its walls. The force of the escaping gas exerts pressure on the two fluids sufficient to fracture the frangible disc members allowing mixing action in the mixing chamber. The mixed fluid chemically reacts to produce light and flows from the mixing chamber to a light transmittable material where it is stored to provide an illuminated area. 
         [0011]    While each of the prior art references provide projectiles which may mark a target, they all suffer from the disadvantages of either being incendiary, not effective for night time and day time detection, or require mixing of chemicals to be activated. Therefore, what is needed is a luminescent projectile containing a material that overcomes the disadvantages of the prior art. 
         [0012]    Triboluminescent materials, described as having the ability to emit light upon application of mechanical energy, is well known in the prior art. Such materials are disclosed in U.S. Pat. Nos. 6,071,632, 6,117,574, 7,230,127, and 7,242,443. 
         [0013]    U.S. Pat. No. 6,820,496 discloses a light emitting device which comprises a plurality of triboluminescent particles dispersed throughout an elastomeric body. The materials are activated by deforming the body, effectively transferring mechanical energy to some portion of the particles. The light emitted by these mechanically excited particles is collected and directed into a light conduit and transmitted to a detector/indicator means. 
         [0014]    U.S. Pat. No. 5,905,260 discloses a damage sensor for detecting damage within a structure such as aircraft wings or fuselage, or a bridge. The sensor comprises a small piece of a triboluminescent material connected via light guiding fibers or layers to one or more detectors. The sensor may be embedded within the structure or mounted on its surface. Impact of objects on the structure causes a physical damage to the triboluminescent material. Such damage causes light emission which is detected and recorded for later observation. The intensity of emission may be measured to give an indication of amount of damage received by the structure. Several different triboluminescent materials may be arranged in different location within the structure so that location of damage may be detected by a single detector sensitive to the different wavelengths of light emitted by the several materials. Light from the triboluminescent material may be detected directly by the detectors. Alternatively, material doped with suitable photo excitable dyes may be used to photo excite. 
         [0015]    U.S. Pat. No. 6,710,328 discloses a composite structure which contains crystalline and/or polycrystalline triboluminescent elements distributed throughout the structure. The structure is further coupled with at least one optical fiber. Each optical fiber is exteriorly light transparent/translucent along at least a longitudinal portion thereof which is positioned in the vicinity of at least one triboluminescent element. Concomitant with the occurrence of damage in and/or on the structure is the occurrence of mechanical action with respect to at least one triboluminescent element. As a consequence of the mechanical stress, the materials emit light which ultimately gets transmitted to remotely located photosensitive equipment. 
         [0016]    U.S. Pat. No. 4,020,765 discloses a warhead assembly having an explosive and a detonator for activating an explosive, a fuze comprising a triboluminescent material coated on the interior portion of the assembly, a photo-sensitive detector for detecting the light caused by the triboluminescent material upon impact of the warhead assembly, and means responsive to said photo-sensitive detector and communicating with said detonator so as to cause the detonator to activate and detonate the explosive. 
         [0017]    U.S. Pat. No. 4,372,211 discloses a round assembly having a propellant and an igniter for activating the propellant, a thermoelectric power supply comprising a plurality of junctions, which are coupled to the propellant for sensing the propellant temperature, and means of generating a voltage in response to the temperature sensed by the junction 
         [0018]    U.S. Pat. No. 7,278,290 discloses a projectile impact energy and location measurement system which employs a target apparatus having an impact plate of a solid durable substance such as steel or titanium. Disposed over the plate is a layer of elastoluminescent material composed of zinc sulfide and manganese embedded in an elastomeric composite. This luminescent material is designed to emit light or exhibit luminescence when elastically strained, for example when a projectile strikes the material. Optical photosensitive sensors are deployed at strategic locations to observe and record color images of the target before during and after impact by a projectile. The disadvantage of this system is that the detection of light is performed in a controlled environment in which the target is required to contain elastoluminescent materials. 
       SUMMARY OF THE INVENTION 
       [0019]    The present invention is an apparatus and method of making triboluminescent materials for use within projectiles, the triboluminescence causing the production of light upon the projectile impacting a target. Triboluminescence, also known as mechanoluminescence or fractoluminescence, is the ability of some materials to emit light upon application of mechanical energy. Light output is based upon the fracture of triboluminescent material crystals, a process known to occur in both organic and inorganic materials with some materials capable of producing light intense enough to be visible. 
         [0020]    The instant invention encompasses luminescent projectiles useful for identifying a point of impact and includes one or more triboluminescent materials contained therein. The projectile can be of any shape or size which is constructed and arranged to be combined with at least one triboluminescent material. The projectile, in combination with the triboluminescent materials, provides a user with identification of the target-projectile point of impact. 
         [0021]    In a particular illustrative embodiment, the triboluminescent material is coated on the outer surface of the projectile body. The projectile body may also contain the triboluminescent materials within a reservoir. The triboluminescent materials may be press fit together to form unitary projectile capable of being fired from a weapon. During the process of firing and exiting the weapon, the luminescent projectile does not produce light. However, upon striking a target, the impact produces enough mechanical stress on the triboluminescent material so as to cause the materials to emit light. Depending on the types of triboluminescent materials used, light production can be varied, such as visible light, infrared light, or light associated with certain wavelengths. Additionally, triboluminescent materials may also be combined with mechanical stress inducing materials. As used herein, the term “mechanical stress inducing materials” means any material that may cause or enhance the impact force used to activate the triboluminescent material, including, but not limited to steel ball bearings. 
         [0022]    Accordingly, an objective of the instant invention to teach a luminescent projectile containing triboluminescent materials. 
         [0023]    It is a further objective of the instant invention to teach a luminescent projectile containing triboluminescent materials which emits light upon impact with a target. 
         [0024]    It is yet another objective of the instant invention to teach a luminescent projectile containing triboluminescent materials which emit light upon impact with a target thus providing site identification of the target-projectile impact. 
         [0025]    It is a still further objective of the invention to teach luminescent projectile containing triboluminescent materials which emits light upon impact with a target, thus exhibiting site identification of the target-projectile impact. 
         [0026]    Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with any accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. Any drawings contained herein constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0027]      FIG. 1  is a plane view of a projectile; 
           [0028]      FIG. 2  is a plane view of the luminescent projectile containing triboluminescent materials coated on the outer surface; 
           [0029]      FIG. 3  is a pictorial view of a projectile having an inner reservoir; 
           [0030]      FIG. 4  is a pictorial view of a projectile having an inner reservoir including triboluminescent materials; 
           [0031]      FIG. 5  is a pictorial view of a projectile containing triboluminescent materials and mechanical stress inducing materials within an inner reservoir. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    Now referring to  FIG. 1 , illustrated is a conventional projectile depicted by a generally cylindrically shaped body  10  having a rounded proximal end  12  and a distal base end  14 . The body  10  is formed by a continuous outer side surface  16 . An inner cavity of a projectile may include lethal or non-lethal shot. In the instances of self contained ammunition, the body  10  may further include a propellant. Although the figure illustrates a generally cylindrically shaped body  10  having a rounded front end  12  and linear base  14 , any shape is within the scope of the invention. 
         [0033]    In an illustrative embodiment as exemplified in  FIG. 2 , outer side surface  16  of a projectile is coated or impregnated with one or more triboluminescent materials  18 , including but not limited to zinc sulfide doped with manganese or the crystals of Europium Tetrakis and Neodonium Tetrakis. Any triboluminescent material known or later developed is contemplated by the invention. The outer surface may be coated with the triboluminescent materials in any manner which allows the triboluminescent materials to remain on the surface, including use of adhesive materials such as acrylics, silicones, urethanes, acrylates and epoxy based adhesives which may include adducts of bisphenol-A and epichlorhydrin cured by polyamine or anhydride initiators, and similar adhesives based on other epoxides, UV curable and thermally curable adhesives based on acrylic, vinylic, styrenic, or thiol/ene monomer systems, cyanoacrylate adhesives, pressure sensitive adhesives, hot melt adhesives, latex based adhesives, PVA adhesives, solvent based adhesives, urea formaldehyde and melamine formaldehyde adhesives, anaerobic adhesives, bis-diallyamine derived adhesives or the like capable of securing triboluminescent material to the surface of the projectile. As illustrated in the figure, triboluminescent materials  18  are coated along the entire outer surface  16  in a uniform manner so as to not to affect projectile operation. However, it is important to note that the triboluminescent materials may be coated anywhere along the outer surface of the body of the projectile including placement along the base only so as to allow better projection handling. 
         [0034]    In addition to coating the triboluminescent materials along the outer surface, the materials may be incorporated within one or more reservoirs formed in the projectile which communicates with the projectile&#39;s surface so that light emission occurs upon impact. Referring to  FIGS. 3 and 4 , the projectile body  10  may contain an inner reservoir  20  containing triboluminescent materials  18 . the reservoir eliminates any possible tracing effect and is ruptured upon impact. In another illustrative example,  FIG. 5  exemplifies inner reservoir  20  having triboluminescent materials  18  and mechanical stress inducing material  22 . 
         [0035]    In practice, the luminescent projectile, including but not limited to pellets, bullets (large and small caliber), rounds, missiles, or similar devices which can be adapted or constructed to be loaded into any weapon, including, but not limited to, small caliber arms such as hand guns, rifles, machine guns, large caliber guns, large and small scale artillery, infantry support weapons, weapons mounted on vehicles, tanks, ships, or aircraft, and fired at a target. Upon striking a target, the impact produces enough mechanical stress on the triboluminescent material so as to cause the materials to emit light. Depending on the types of triboluminescent materials used, light production can be varied, such as but not limited to visible light, infrared light, light associated with certain wavelengths, or combinations thereof. Light emission is non-incendiary. 
       EXAMPLE 1 
       [0036]    A .45 caliber bullet was coated with triboluminescent materials. Prior to firing the weapon, the bullet was coated along the outer surface with triboluminescent materials, including but not limited to, zinc sulfide doped with manganese. Other triboluminescent materials may include crystals of Europium Tetrakis or Neodonium Tetrakis. Triboluminescent materials were coated to the bullet using contact adhesives. After coating the bullet in adhesive materials, the bullet was rolled in triboluminescent materials such that the triboluminescent materials adhered to the bullet in sufficient manner so as to not inhibit the ability of the bullet to be fired from a weapon. After adhesion, the bullet was placed in a weapon and fired at a target. The coated bullet emitted a flash of light which was not a spark upon hitting an aluminum target. 
       EXAMPLE 2 
       [0037]    Using a .45 caliber bullet, a reservoir was drilled into the nose of the bullet. To the reservoir, triboluminescent materials, such as zinc sulfide doped with manganese, was added. Other triboluminescent materials placed into the reservoir may include crystals of Europium Tetrakis or Neodonium Tetrakis. The triboluminescent materials were press fitted into the reservoir and placed in a weapon. Upon firing the weapon, the bullet hit an aluminum plate. Upon impact with the plate, the bullet emitted a visible flash. 
       EXAMPLE 3 
       [0038]    Using a .45 caliber bullet, a reservoir was drilled into the nose of the bullet. To the reservoir, triboluminescent materials, such as zinc sulfide doped with manganese, was added. In this example, the triboluminescent materials filled only a portion of the reservoir. To the half-filled reservoir, mechanical stress inducing materials, such as but not limited to steel ball bearings, were added. The mechanical stress inducing materials were press fit into the reservoir and sealed. Other triboluminescent materials filled into the reservoir may include crystals of Europium Tetrakis or Neodonium Tetrakis. Upon firing the weapon, the bullet hit an aluminum plate and upon impact emitted a visible flash. 
         [0039]    The use of the .45 caliber is for reference only. The triboluminescent material can be applied to any size bullet from 5 mm through 30 mm and greater. Bullets include round nose, full metal jacket, partition bullets, boat tail, spire point hollow point and so forth. Shells and cartridges and be rimless, rimmed, belted, self propelled or externally propelled. 
         [0040]    All patents and publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. 
         [0041]    It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and any drawings/figures included herein. 
         [0042]    One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objectives and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments, methods, procedures and techniques described herein are presently representative of the preferred embodiments, are intended to be exemplary and are not intended as limitations on the scope. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention and are defined by the scope of the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in the art are intended to be within the scope of the following claims.