Patent Publication Number: US-2016231095-A1

Title: Limited range lethal ammunition

Description:
BACKGROUND 
     The present invention pertains to ammunition that is lethal for a predetermined limited distance or time. 
     Currently, projectiles that are commonly available to be fired from guns and cannons against human targets can be generally categorized as being lethal or less than lethal. Other uncommon projectiles are available, but are generally of a highly specialized type such as projectiles with electronic payloads, illumination projectiles, tracers, or others. The demand for less than lethal ammunition is becoming more prominent by police forces, military forces, and common citizens alike. Less than lethal ammunition is ammunition that is less likely to kill a living human target than are more traditional lethal weapons. However, there are several instances where projectiles are needed that are lethal for a given time or range and then become less than lethal to avoid collateral damage to unintended targets. 
     As previously stated, most current projectiles are generally designed to be only lethal or only non-lethal after being fired. Many different types of lethal projectiles are available. In small arms, examples include full metal jacket, hollow point, sabot, incendiary, and even high explosive rounds. Each type of projectile is designed to be more effective against a specific target set. Larger caliber projectiles can be designed with even more variation. Large caliber projectiles generally include the same types of projectiles as small arms, but additionally include chemical, white phosphorus, HEAT (High-Explosive, Anti-Tank), and other variants such as SAPHEI (Semi-Armor Piercing, High Explosive, Incendiary). Many of these larger caliber projectiles can be outfitted with a variety of fuzes including point detonation, timed, and active radar. Small caliber projectiles are generally defined as projectiles that have a diameter less than thirteen and a half millimeters (such as a 0.50 caliber rounds and below) and are generally fired from a weapon that can be transported by a person or two people. Large caliber projectiles are generally fired from weapon systems that require mechanical aids to be transported and/or fired. Examples of these systems include artillery, tanks, naval guns, etc. 
     Less than lethal projectiles also come in many variations. For example, there currently exist bean bag projectiles, rubber bullets, pepper rounds, and other chemical rounds. A still further type of ammunition exists specifically for use on target ranges. For example, there are large caliber projectiles that are designed to break apart in midair in order to limit their range and break apart into relatively large sections. There are also small caliber flechette rounds that are designed to break apart into small pieces upon impact with a solid surface. These rounds are generally designed to be used in target ranges or, in the case of flechette rounds, for home defense. When used for home defense, the rounds are designed to avoid inadvertent collateral damage by breaking apart into many small pieces when they strike a wall or other such surface instead of penetrating the wall and potentially impacting an innocent bystander. 
     The projectiles described above fill a certain roll, whether being designed to eliminate a specific target, to dissuade or injure a target, or to help prevent rounds from leaving a training or residential area. However, the rounds described above do not begin their trajectory in a lethal form to later transition to a less than lethal form after a predefined time or distance after being fired so as to control collateral damage to unintended targets. US Patent application 2002/0152914 discloses a projectile that attempts such a configuration with an internal cavity containing a combustion charge activated by a fuze. After leaving a barrel, the fuze is ignited via the ignition of the propellant used to propel the projectile. After the combustion charge is activated, it burns at high temperature to liquefy the projectile and therefore render it less than lethal. However, this round has several disadvantages. The heat that the charge generates creates hazards in itself. The heated projectile can burn a target, especially if the charge is ignited after the round penetrates a human target. Additionally, the rounds can create fire hazards. The initial lethality of the round can also be compromised as the internal cavity for the combustion charge is filled with low density material. The composition of the round must be carefully selected as well to insure that it liquefies at a desirable temperature. Finally, the storage parameters of this round are not ideal as they must be stored to avoid high temperatures in order not to degrade the round. 
     Thus, there is a need for improvement in this field. 
     SUMMARY 
     Disclosed is a fragmenting lethal projectile that, if it does not earlier impact an object, is lethal for a predetermined time or distance after being fired and then fragments into substantially solid pieces that are each less than lethal to an average human. The attributes of the fragments that make them less than lethal can be expressed in different ways. The fragments can impart an energy density of no more than ten J/cm 2  into an impact area, or even six J/cm 2 . The mass of each projectile can be less than five grains, two grains, or even one grain. Alternatively, the fragments on average can be dictated by the equation ln(M*d)&gt;ln(m*v 2 −7.5 where M=a mass of 45 kg, d=the largest cross sectional dimension of said piece in cm, m=the mass of said piece in g, and v=the velocity of said piece in m/s. 
     The number of fragments that the projectile fragments into can preferably be greater than one hundred or more preferably greater than five hundred. The number of pieces can be defined per millimeter diameter of the projectile prior to fragmentation. The projectile can preferably fragment into ten or more preferably even thirty fragments per millimeter of pre-fragmentation diameter. 
     The projectile can further include a detonating charge. A sleeve can be included which surrounds and is moveable with respect to the detonating charge. The detonating charge can be initiated by a fuze (sometimes spelled “fuse”). The fuze can be initiated by the combustion of propellant used to propel the projectile. Alternatively, the fuze can be initiated by the acceleration of the projectile, preferably at greater than ten thousand g. 
     The projectile can additionally include a mechanism to prevent the fragmentation of the projectile after it strikes a solid. This mechanism can be the deformation of the projectile itself. The projectile can have a diameter of less than thirteen and a half millimeters. The projectile can alternatively include fracture initiating features. 
     An alternate example of the projectile uses a solvent in place of the detonating charge. The body of the projectile can then optionally include a bonding agent that dissolves when in contact with the solvent. The reaction between the bonding agent and solvent can be initiated by a fuze. 
     Another alternate example projectile includes a first mechanism activated after the projectile is fired if the projectile does not strike an object within a predetermined time or distance and that substantially precludes such activation if the projectile strikes an object before said predetermined time or distance. The projectile can also have a casing and be configured and arranged to be fired from a barrel by the activation of propellant that is substantially consumed when the projectile leaves the barrel. 
     Further forms, objects, features, aspects, benefits, advantages, and embodiments of the present invention will become apparent from a detailed description and drawings provided herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view of a projectile having an internal detonating charge to render the projectile less than lethal. 
         FIG. 2A  is a cross sectional view of an alternative arrangement to the fragmentation-neutralizing feature illustrated in  FIG. 1 . 
         FIG. 2B  is a cross sectional view of a third alternative arrangement to the fragmentation-neutralizing feature illustrated in  FIG. 1 . 
         FIG. 2C  is a cross sectional view of a fourth alternative arrangement to the fragmentation-neutralizing feature illustrated in  FIG. 1 . 
         FIG. 2D  illustrates the disk  27  of  FIG. 2A   
         FIG. 3  is a cross-sectional view of a fifth alternative example of a projectile having an internal solvent to render the projectile less than lethal. 
     
    
    
     DESCRIPTION OF THE SELECTED EMBODIMENTS 
     For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. One embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features that are not relevant to the present invention may not be shown for the sake of clarity. 
       FIG. 1  illustrates an example projectile  10  having a detonating charge  12  and a fuze  14 . The projectile can optionally be connected to a shell casing  28  that contains propellant  30 . Such a configuration is common for small arms projectiles and less common for large caliber projectiles. The projectile  10 , as illustrated, includes fracture initiating features  26  such that when the detonating charge  12  explodes, the body  24  of the projectile fragments into smaller pieces. The size and dispersions pattern of these pieces can be controlled by the configuration of these fracture initiating features  26 . These fracture initiating features  26  can take the form of scored material, perforations, open spaces, adjacent pieces of, or imbedded materials, as examples. For example, ceramic particles or sections can be imbedded in the body  24  of the projectile. Alternatively, the body  24  can be comprised of stacked sections of metallic material. 
     The projectile  10  can also include a baseplate  17  with an aperture  16 . The baseplate  17  can further be joined to an external housing  25 . The housing  25  can aid in containing the body  24  and the fracture initiating feature  26 , if, for example, the body is formed from loosely fitting discs or other structures. In this example, the fuze  14  is a chemical fuze that is initiating by the combustion of propellant  30  used to fire the projectile. The aperture  16  allows the gasified propellant to make contact with the fuze  14  to initiate it. The fuze  14  is designed such that it initiates the detonating charge  12  a predetermined time after the fuze  14  is initiated. Fuzes can be chemical based, as is illustrated, inertia fuzes, or other. If inertia fuzes are utilized, a large acceleration force on the projectile can be applied to initiate the fuze in order to avoid inadvertent detonation of the projectile. The fuze can also be electronic and the fuze can be arranged such that it specifies a time or distance for which the detonating charge  12  is initiated. For example, for range the fuze can include a receiver (not shown) to detect an electronic signal from its firing source. The fuze then detonates either after it no longer receives the signal or when it receives a command to detonate based upon time or distance in flight. Alternatively, the fuze can detect that the projectile has travelled a certain distance and then initiate the detonating charge  12 . The projectile can also include a sealing cap  18  to allow the insertion of the fuze  14  and detonating charge  12  during assembly of the projectile  10 . 
     The detonation of the projectile is engineered such that the fragments of the projectile are less than lethal to an average human. Therefore, the projectile can be fired in a lethal state for a predetermined time or range. Outside of this time or range, the projectile is rendered less than lethal to avoid inadvertent fatalities of innocent bystanders. For example, if used by a police officer chasing a criminal, projectiles that miss the intended target of the criminal will be rendered less than lethal after a time or range, decreasing the probability of a bystander being injured and/or killed by the projectile. 
     Several criteria can be used to evaluated the lethality of a projectile. The mass of the projectile as well as its velocity are important contributors to the projectile&#39;s lethality. However, the size of cavitation that a projectile can create as it travels through flesh also can contribute to the projectile&#39;s lethality. It has been found that kinetic energy density is one way of defining lethality. Specifically it is believed that an energy density of ten J/cm 2  will compromise average human skin and six J/cm 2  will compromise an average human cornea. One can define a correlation between the mass of the human target, the diameter of the projectile, the mass of the projectile, and the velocity of the projectile. Specifically, a projectile conforming to the equation ln(M*d)&gt;ln(m*v 2 )−7.5 has been found to be less than lethal, where M=the mass of the target in kg, d=the diamter of the projectile in mm, m= the mass of the projecitle in g, and v=the the velocity of the round in m/s. 
     A projectile with lower mass has less momentum and kinetic energy that a similar projectile traveling at the same velocity. Therefore, a projectile that can be fractured into smaller pieces can become less lethal, not only because the mass of each piece is much smaller, but because the smaller particles may slow more rapidly. Conversely, a projectile that is fractured into more pieces can quickly become less lethal. However, these statement are accurate so long as the fragments themselves are not large enough to have enough kinetic energy and/or momentum to pierce human skin and/or cause significant damage or death to a human target. Many current projectiles such as high explosive artillery and previous shrapnel artillery rounds are examples where the projectile is designed to fragment into pieces large enough to be lethal to intended targets. 
     Advantageously, the projectile disclosed is designed to avoid fragmentation if it strikes a target. This is beneficial, for example, if the round strikes a human that was an intended target. In such an instance, it can be undesirable for the detonating charge to detonate within the human. Therefore, several mechanisms have been disclosed to prevent this occurrence. One is illustrated in  FIG. 1  as concentric cylinders  32  and  22 . In this example, the inner cylinder  22  is held by a loose friction fit within outer cylinder  32 . Therefore, the inner cylinder  22  can move relative to the outer cylinder  32  (the inner cylinder  22  can slide within the outer cylinder  32 ). Additionally, the detonating charge  12  can be joined to the inner cylinder  22  such that they move as a single unit. When the round is fired, the force of the accelerating projectile  10  can cause the inner cylinder  22  and detonating charge  12  rearward such that the detonating charge  12  contacts the fuze  14 . When the projectile  10  strikes a solid surface, the detonating charge  12  slides forward, leaving an air gap  13  between the detonating charge and the fuze  14 . The air gap can serve to prevent the fuze from being able to initiate the detonating charge  12  to detonate. Furthermore, the impact of the projectile  10  and the resulting deformation of the projectile  10  can aid in the separation of the fuze  14  from the detonating charge  12 . 
     An alternative detonation preventing mechanism is illustrated in  FIG. 2A .  FIG. 2A  illustrates the body of the projectile being formed without the sealing cap  18 . Instead, the body  24  of the projectile is formed such that when the projectile  10  strikes a solid surface, the projectile deforms and renders the detonating charge inert. In this example, the body is configured to form a point  25  that interacts with a pushrod  23 . The pushrod can then interact with a disk  27 . Disk  27  can be perforated or, as illustrated in  FIG. 2D , have spokes  51  to connect the pushrod  23  to the rim  50  of the disc  27 . The perforations or openings  51  in the disc allow the fuze  14  to initiate the detonation of the detonating charge  12  during normal operation. However, when the projectile  10  strikes a solid surface prior to the fuze  14  initiating, the pushrod  23  and disc  23  can be configured relative to the forward part of the projectile, to eject the fuze  14  rearward such that it can no longer initiate the detonating charge  12 . 
       FIG. 2B  illustrates yet another example projectile  10 . In this example, the fuze  14  extends longitudinally through the body  26  of the projectile  10 . The detonating charge  12  also extends longitudinally through the body  26  of the projectile and can surround the fuze  14 . The fuze  14  and detonating charge  12  can be configured and arranged such that the fuze  14  contacts the detonating charge via initiation chamber  60 . The initiation chamber  60  in this example enables physical interaction between the fuze and the detonating chamber to initiate the detonation of the detonating charge  12 . Locating the initiation chamber  60  on the front of the bullet enables the defusing of the charge if the round strikes a solid surface. The initiation chamber  60  can deform or otherwise be rendered inoperable by the impact of the projectile  10 , inhibiting the detonation of the detonating charge  12 . 
       FIG. 2C  illustrates a variation of the projectile of  FIG. 2B . In this example, the fuze  14  is locating towards the exterior of the projectile  10 . The fuze  14  can be located within channels  62  along the surface  63  of the projectile. The surface  63  can be a thin metallic or other covering around the body of the projectile. The channels  62  can extend through one or multiple paths through the surface  63  of the projectile. Alternatively, the channels  62  can extend through the body  24  of the projectile. The initiation chamber  64  in this example functions similarly the initiation chamber  60  of  FIG. 2B . Advantageously, the greater separation of the fuze  14  from the detonating charge  12  can increase the probability that the projectile  10  will be defused if it strikes a solid surface prematurely by decreasing the probability that the fuze  14  will make contact with the detonating charge  12 . 
       FIG. 3  illustrates another example projectile. The projectile in this illustration  40  includes a solvent  44  in a container  45  and a fuze  42 . The fuze  42  acts similarly to the fuze  14  previously described in that upon reaching the container  45 , it consumes the container  45 , releasing the solvent to permeate channels  48  to more evenly be distributed to improve the dispersion of the solvent through the projectile  46  material. In this projectile, the fuze acts on container  45  within the projectile  46  to consume the container  45 , thereby releasing the solvent to flow into pathways to dissolve binding agents so that the projectile is converted into numerous smaller fragments. This can be accomplished through the addition of a binding agent to the body of the projectile  46  which the solvent rapidly dissolves. Optionally wetting agents can be included along channels  48  to aid in the dispersion of the solvent. The channels  48  can be designed to alter the fragmentation pattern of the projectile  46  or to improve the contact between the solvent  44  and the projectile  46  after the fuze  42  has initiated the dispersion or activation of the solvent  44  by consuming container  45 . Additionally, the projectile  46  can also include features (not shown) analogous to those shown in earlier FIGS. to prevent the dispersion or activation of the solvent  44  after it strikes a solid surface. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes, equivalents, and modifications that come within the spirit of the inventions defined by following claims are desired to be protected. All publications, patents, and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent, or patent application were specifically and individually indicated to be incorporated by reference and set forth in its entirety herein.