Abstract:
A mine defeating projectile includes a housing defining an inner cavity, a plurality of channels extending through a front surface of the housing and to the inner cavity, and a plurality of cutout sections extending through as side wall thereof. The projectile further includes a fragmentation sleeve disposed in the inner cavity of the housing and a slider sleeve disposed in the inner cavity of the housing abutting an aft end of the fragmentation sleeve. The slider sleeve includes an explosive train and the slider sleeve is frangibly attached to the housing. The projectile further includes a finned section attached to an aft end of the housing. The finned section defines a protrusion for initiating the explosive train. The protrusion is spaced apart from the explosive train.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/151,294; filed 10 Feb. 2009; and entitled “Mine-Defeating Projectile,” which is hereby expressly incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to submunitions, and particularly to small-scale submunitions used in mine destruction applications. 
     2. Description of Related Art 
     The use of small-scale projectiles capable of individually defeating land or under-water mines has proven to be a successful method of neutralizing mines within a coverage area. In order to ensure destruction of a mine, current systems require the explosive payload of the projectile to be detonated while intimately coupled with the energetic fill of the mine. Moreover, in order to successfully defeat a mine, current projectiles must employ high energy explosive material of such quantity that a safe and arm mechanism is required to be integrated to meet modern safety standards. Traditional safe and arm mechanisms suffer problems including failing to fit within the housing of small-scale projectiles. Improvements to small-scale projectiles capable of defeating mines are thus desired. 
     There are many designs of submunitions used in mine destruction applications well known in the art, however, considerable shortcomings remain. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. However, the invention itself, as well as, a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a diagram illustrating an isometric view of a projectile in accordance with an exemplary embodiment of the invention; 
         FIG. 2  is a diagram illustrating an exploded view of the exemplary projectile of  FIG. 1 ; 
         FIG. 3  is a diagram illustrating an exploded view of an exemplary slider sleeve in accordance with the exemplary projectile of  FIG. 1 ; 
         FIG. 4A  is a diagram illustrating a cross-sectional view of the exemplary projectile of  FIG. 1 ; 
         FIG. 4B  is a diagram illustrating an enlarged view of a portion of the cross-sectional view of  FIG. 4A ; 
         FIG. 5A  is a diagram illustrating operation of the exemplary projectile of  FIG. 1  during an exemplary mine impact scenario; 
         FIG. 5B  is a diagram illustrating operation of the exemplary projectile of  FIG. 1  during an exemplary mine impact scenario; 
         FIG. 5C  is a diagram illustrating operation of the exemplary projectile of  FIG. 1  during an exemplary mine impact scenario; and 
         FIG. 5D  is a diagram illustrating operation of the exemplary projectile of  FIG. 1  during an exemplary mine impact scenario. 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
     Referring to  FIG. 1 , a side and top view of a projectile  100  is shown in accordance with an exemplary embodiment of the invention. The projectile  100  has a generally cylindrical body, symmetrical in rotation about an axis  101 . The projectile  100  has a forward end  102  and an aft end  104 . The projectile comprises a housing  110  having a blunt nose section  112  located at a forward end of the housing  110  and a main body  114 . The blunt nose section  112  has a flat forward face for allowing the projectile to supercavitate when traveling through water and to create a terra-dynamic cavity when traveling through sand or other such earthen materials. The main body  114  of the projectile housing  110  includes a plurality of cutout sections labeled generally as  115 . The cutout sections  115  are configured to allow projectile fragments to be expelled from an inner cavity of the housing  110  after mine impact. By way of example only, the projectile housing  110  may be comprised of tungsten. The projectile  100  further comprises a frangible barrier  130  having a plurality of sections labeled generally as  132  separated by perforations  134  (only one labeled for clarity). The frangible barrier  130  is symmetrically disposed about an aft end of the blunt nose section  112  and a forward end of the housing  110 . The perforations  134  separating each section  132  of the frangible barrier  130  are sized to hold the frangible barrier intact while traveling through water or sand overburdens and to detach upon impact with a mine casing, such as a metal mine casing, or a mine&#39;s energetic fill. By way of example only, the frangible barrier  130  may be comprised of aluminum, such as 7075-T6 aluminum. 
     Still referring to  FIG. 1 , the projectile  100  further comprises a finned section  120  located aft of the projectile housing  110 . The finned section  120  includes a plurality of fins  122  located proximate the aft end of the finned section. The finned section  120  may also be comprised of aluminum, such as 7075-T6 aluminum. By way of example only, the projectile  100  may be approximately 5.5 inches in length and have an outer diameter of about 0.44 inches. In one configuration, the projectile weighs approximately 56 grams. The projectile  100  may also have a center of gravity located approximately 1.7 inches aft of the forward end  102  of the projectile  100 . It is noted that the scale of the projectile is in no way limited to the exemplary embodiment and may be reduced or extended in size. 
     Referring now to  FIG. 2 , a diagram is shown illustrating an exploded view of the exemplary projectile  100  of  FIG. 1 . As shown, the projectile housing  110  further comprises a plurality of cylindrical cutouts  116  symmetrically disposed about the axis  101 . The cylindrical cutouts  116  may be formed as bore holes and are of sufficient size to allow an energetic fill of a mine to enter an inner cavity of the projectile housing  110  after the projectile  100  impacts the mine. Cylindrical cutouts  116  may alternately be shaped as slots having sufficient size to allow the energetic fill of the mine to flow into the inner cavity of the projectile housing  110 . The projectile  100  further comprises a fragmentation sleeve  210 . The fragmentation sleeve  210  has an outer diameter sized to mate with an inner diameter of the projectile housing  110 . The inner diameter of the fragmentation sleeve  210  is sized to allow the fragmentation sleeve to break apart and propel through the cutout sections  115  of the projectile housing  110  upon projectile detonation. In particular, the thickness of the wall of the fragmentation sleeve  210  are sufficiently small relative to the inner diameter of the fragmentation sleeve  210  to allow fragments to be expelled with sufficient velocity to cause the energetic fill of the mine to detonate. By way of example only, the fragmentation sleeve  210  may be comprised of 303 stainless steel and may have a thickness of approximately 0.005 inches. The fragmentation sleeve  210  may also include one or more vent holes  212  that allow air to escape as the energetic fill of the mine flows in to the fragmentation sleeve  210 . 
     Still referring to  FIG. 2 , the projectile  100  further comprises a slider sleeve  220  which is inserted in the aft end of the projectile housing  110 . An outer surface  223  of the slider sleeve  220  may be threaded to allow the slider sleeve  220  to be removably inserted into the aft end of the projectile housing  110 . The slider sleeve  220  has an outer diameter sized to mate with the inner diameter of the aft end of the projectile housing  110 . The slider sleeve  220  has an inner surface sized to receive a plurality of additional energetic components, as are discussed in greater detail herein. By way of example only the slider sleeve  220  may be comprised of AISI S7 tool steel. As shown, the finned section  120  of the projectile  100  also has a protrusion  201  that extends from the forward end of the finned section  120  and is involved in initiating detonation of the projectile  100 . The finned section  120  may also have a threaded surface  124  located proximate the forward end of the finned section  120 . The threaded surface  124  is adapted to allow the finned section  120  to be removably inserted into the aft end of the projectile housing  110 . 
     Referring now to  FIG. 3 , a diagram is shown illustrating an exploded view of an exemplary slider sleeve  220  and elements disposed therein in accordance with the exemplary projectile  100  of  FIG. 1 . As shown, the slider sleeve  220  has a plurality of circular cutout sections  226  sized to receive a corresponding plurality of shear pins  312 . By way of example only, two circular cutout sections  226  may be located on opposite sides of the slider sleeve  220 . Two corresponding shear pins  312  may be employed for insertion into each of the circular cutout sections  226 . The shear pins  312  may be comprised of high strength steel. The slider sleeve  220  also includes an energetic column slider  320  having a forward section  324  and an aft section  322 . The outer diameter of the aft section  322  is larger than the outer diameter of the forward section  324 . The outer surface of the energetic column slider  320  is sized to mate with an inner surface of the slider sleeve  220  and to allow the energetic column slider  320  to move freely relative to the slider sleeve  220 . As shown, the energetic column slider  320  has a plurality of circular cutout sections  326 , corresponding to the plurality of shear pins  312 , also sized to receive the plurality of shear pins  312 . The energetic column slider  320  also has a closed forward face  328  and a substantially hollow inner cavity sized to receive an insensitive energetic component  330 , a sensitive energetic component  340 , and a percussion primer  350 , which define an explosive train. The aft end of the energetic column slider  320  is open to receive these energetic components. By way of example only, the energetic column slider  320  may be comprised of AISI 303 stainless steel. The insensitive energetic component  330  may be a high energy, insensitive explosive material, such as a combination of octagon and vinylidine fluoride-hexafluoropropene polymer, for example, PBXN-5, or the like. The sensitive energetic component  340  may be deflagration-to-detonation material, such as DXN-1 or the like. The percussion primer  350  may be a M42C2 primer or the like. Each of these energetic components has corresponding outer diameters that allow the energetic components to be pressed into the aft end of energetic column slider. 
     Referring now to  FIG. 4A  and  FIG. 4B , diagrams are shown illustrating a cross-sectional view of the exemplary projectile  100  of  FIG. 1 .  FIG. 4B  illustrates an enlarged view of a portion of projectile  100 , as indicated in  FIG. 4A . The projectile housing  110  includes an inner cavity labeled as  410 . The inner cavity  410  is connected to the cylindrical cutout sections  116 . As shown, the cylindrical cutout sections  116  are inwardly angled to connect to the inner cavity  410  of the projectile housing  110 . A flat section  412  may also be included to reduce the likelihood that an internal component, such as the front surface  328  of the energetic column slider  320 , will exit the projectile if an inadvertent detonation of the projectile occurs. One or more catches may also be included along the cylindrical cutout sections  116  in order to provide additional safety barriers without significantly impeding the flow of the energetic fill of the mine. As shown, the shear pins  312  secure the relative positions of the slider sleeve  220  and the energetic column slider  320 . The forward face of the finned section  120  also secures the slider sleeve  220  in place against a shoulder section  430  of the inner surface of the projectile housing  110 . The outer diameter of the aft section  322  of the energetic column slider  320  is larger than an inner diameter D of the projectile housing  110 . In this manner the energetic column slider  320  is supported by the shoulder section  430  of the projectile housing  110  thereby preventing the shear pins  312  from being defeated as a result of external forces applied to the projectile  100 . The energetic column slider  320  has an overall length shorter than that of the slider sleeve  220 . As a result of the difference in overall length, along with the positioning of the shear pins  312 , an offset gap  440  is formed between the aft end of the energetic column slider  320  and the forward face of the finned section  120  when the projectile  100  is assembled. The percussion primer  350  is sized so that the aft end of the percussion primer  350  is aligned with the aft end of the energetic column slider  320 . In this manner the same offset gap  440  exists between the percussion primer  350  and the forward end of the finned section  120 . 
     Still referring to  FIGS. 4A and 4B , the protrusion  201  of the finned section  120  is located within the gap offset  440  when the projectile  100  is assembled. By way of example only, the protrusion  201  may be about 0.025 inches, measured from a forward end to an aft end. The offset gap  440  may be approximately 0.0625 inches measured from the aft end of the percussion primer  350  to the forward face of the finned section  120 . A detonation sequence is initiated by impacting the percussion primer  350  with the protrusion  201 . As configured, the offset gap  440  prevents the protrusion  201  from contacting the percussion primer  350  while shear pins  312  are intact. The shear pins  312  may be defeated only by application of an aftward force applied at the forward surface of the energetic column slider  320 . Since the energetic column slider  320  is located within the projectile housing  110 , the need for a separate safe and arm mechanism is advantageously eliminated. Operation of the exemplary projectile  100  during an exemplary mine-impact scenario will now be discussed with reference to  FIGS. 5A-5D . 
       FIG. 5A  is a diagram illustrating operation of the exemplary projectile  100  of  FIG. 1  during an exemplary mine impact scenario. In the exemplary scenario a projectile  100  impacts a surface  512  of mine  510 , after having traveled through one or more media, such as water, air and/or sand. Note that in  FIGS. 5A-5D , mine  510  is represented in phantom to better reveal the exemplary operational characteristics of the projectile  100 . The frangible barrier  130  substantially prevents entry of such media into the inner cavity  410  of the projectile housing  110 . The frangible barrier  130  is also adapted to be of sufficient structural integrity to remain intact while traveling through such media. In this manner, premature detonation of the projectile is prevented. The frangible barrier  130  is, however, also adapted to break apart upon impacting a material of sufficient hardness, such as a metal mine housing. When attempting to defeat mines having a plastic housing, the frangible barrier  130  will be adapted to break apart upon impact with the energetic fill, such as TNT, of the mine.  FIG. 5A  illustrates the manner in which the frangible barrier  130  will break apart, in effect zippering apart at seams defined by the perforations  134  from an aft end to a forward end of the frangible barrier  130 . After the frangible barrier  130  breaks away from the projectile housing  110 , cylindrical cutouts  116  are exposed allowing the energetic fill of the mine to flow into the projectile housing  110 . 
     Referring now to  FIG. 5B , another diagram is shown illustrating operation of the exemplary projectile  100  of  FIG. 1  during an exemplary mine impact scenario. In particular,  FIG. 5B  illustrates the flow of the energetic fill of the mine into the projectile housing  110  as the projectile penetrates deeper (relative to  FIG. 5A ) into the mine. The flow of the energetic fill through the cylindrical cutout sections  116  and into the inner cavity  410  of the projectile housing is indicated by arrows  520  and  530 . At this point in time, the energetic fill has begun to flow into the inner cavity  410  but has yet to impact the forward face of the energetic column slider  320 . As such, the shear pins  312  remain intact and the offset gap  440  is still in place. 
     Referring now to  FIG. 5C  and  FIG. 5D , diagrams are shown illustrating operation of the exemplary projectile of  FIG. 1  during an exemplary mine impact scenario.  FIG. 5D  illustrates an enlarged view of a portion of projectile  100 , as indicated in  FIG. 5C . In particular,  FIG. 5C  and  FIG. 5D  illustrate the state of the projectile shortly after the energetic fill of the mine has impacted the forward face  328  of the energetic column slider  320 . As shown, the shear pins  312  are defeated as a result of the aftward force caused by the mass flow rate of the energetic fill of the mine entering the inner cavity  410 . After the shear pins  312  are defeated the force of the energetic fill pushes the energetic column slider  320  along with energetic components  330 ,  340  and  350  aftward. The offset gap  440  closes and the percussion primer  350  impacts the protrusion  201  of the finned section  120  of the projectile  100 . In this manner, the protrusion  201  acts as a firing pin that initiates detonation of the energetic components of the projectile  100 . Initiation of the percussion primer  350  initiates the higher energy sensitive energetic component  340 . Initiation of the sensitive energetic component  340  in turn causes the high explosive energetic component  330  to detonate. At this point, the inner cavity  410  of the projectile housing  110 , surrounded by fragmentation sleeve  210 , has filled with the energetic fill of the mine. Detonation of the high explosive energetic component  330  will in turn initiate detonation of the energetic fill of the mine that is encased within the inner cavity  410 . Initiation of the energetic fill of the mine located within the inner cavity  410  will cause the fragmentation sleeve  210  to break apart expelling fragmented sections through the cutout sections  115  of the projectile housing  110 . The expelled fragmented sections of the fragmentation sleeve  210  in turn initiate detonation of the energetic fill of the mine. High order detonation or deflagration of the mine fill may also be initiated by allowing the detonation wave within the inner cavity  410  of the projectile  100  to travel forward through the cylindrical cutouts  116  into the adjacent mine fill. Since the energetic material of the mine is used to initiate this fragmentation, the amount of insensitive high explosive material  330  required to detonate the mine can advantageously be reduced relative to existing mine-defeating projectiles. By way of example only, the amount of insensitive high explosive material may be about 0.05 grams. Reducing the amount of insensitive material to such a level along with the novel construction of the projectile advantageously eliminates the need for a separate safe and arm mechanism. The projectile  100  can be initiated in a human hand and by modern safety standards is considered to be “hand safe”. 
     According to embodiments of the present invention the mine-defeating projectile having described herein provides a small-scale projectile capable of defeating land mines without the need for a safe and arm mechanism. 
     The present invention provide significant advantages including, but not limited to, (1) providing a projectile that includes only a small amount of explosive but is effective in defeating mines and (2) providing a projectile that requires no safe and arm mechanism but is effective in defeating mines. 
     The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below. It is apparent that an invention with significant advantages has been described and illustrated. Although the present invention is shown in a limited number of forms, it is not limited to just these forms, but is amenable to various changes and modifications without departing from the spirit thereof.