Abstract:
A shaped charge explosive device is provided having a front, a rear and an axis of symmetry with the device comprising an explosive charge, a liner lining a front of the explosive charge, the liner having a recess in the form of a groove encircling the axis of symmetry; and the groove arranged to provide an axis of projection for the liner at an angle A relative to the axis of symmetry. A method of cutting a structure is provided comprising the steps of providing the foregoing device, detonating the explosive charge to create a detonation wave; forming the liner into an formed projectile in the shape of an annular ring with the detonation wave; directing the formed projectile towards the structure; and forming an annular ring cut pattern in the structure with the formed projectile.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an explosive device having a shaped explosive charge to form a projectile. More particularly, the present invention relates to an explosive device comprising an annular shaped linear shaped charge to form an elongated explosively formed annular ring shaped projectile, which may be used as a cutting tool to form an annular ring shaped cut pattern in a structure. 
     BACKGROUND 
     A shaped charge may be understood to be a device having an explosive charge shaped to focus the effect of an explosive&#39;s energy. The shaped charge may be of a shape having a cavity therein, which is opposite the initiation train. If the cavity does not contain a liner, such may be referred to as an unlined shaped charge. Alternatively, if the cavity does contain a liner, such may be referred to as a lined shaped charge. 
     Conventional lined shaped charges are constructed with a charge casing, a hollow conical liner within the case, and the explosive charge positioned between the liner and case. A detonator is activated to initiate the explosive material to generate a detonation wave. This wave collapses and compresses the liner to form a high velocity jet and a slower moving slug as known to the art. The jet properties depend on the charge shape, the energy released, the liner mass and the liner composition. 
     U.S. Statutory Invention Registration No. H1216 in the name of Vigil et al., which published Aug. 3, 1993, discloses a linear shaped charge with rectangular shape. Due to the oblong configuration thereof, such may not be well suited for applications such as a warhead, which may better have a cylindrical configuration to better facilitate use with rockets, missiles, torpedoes and other self-propelled bombs. 
     U.S. Patent Application Publication No. 2006/0075888 in the name of Yang et al., which published Apr. 13, 2006, discloses a radial linear shaped charge pipe cutter. Thus, the jet disclosed therein appears to travel radially rather than axially, and does not appear capable of forming an annular ring shaped cut pattern. 
     While the above appear to contribute to the art of explosive devices, there is still a need for improvement. It is an object of the present invention to improve upon the art of explosive devices by providing an annular shaped linear shaped charge to form an elongated explosively formed annular ring shaped projectile, which may be used as a cutting tool to form an annular ring shaped cut pattern in a structure. 
     SUMMARY 
     According to one object of the invention, a shaped charge device may be provided comprising an explosive charge, a liner lining a front of the explosive charge with the liner having a recess in the form of a groove encircling an axis of symmetry and the groove arranged to provide an axis of projection for the liner at an angle B relative to the axis of symmetry. In certain embodiments, the angle B may be in the range of and all increments between 1 degree to 45 degrees with the axis of projection diverging along the axis of symmetry from a rear of the device towards a front of the device. 
     The groove may be V-shaped and circular or polygonal, and may have an apex angle A in the range of and all increments between 20 degrees to 140 degrees. The groove may be defined by an outer wall portion of the liner and an inner portion of the liner relative to the axis of symmetry, with the outer wall portion of the liner converging along the axis of symmetry from the front of the device towards the rear of the device while the inner wall portion diverges along the axis of symmetry from the front of the device towards the rear of the device. The outer wall portion and the inner wall portion may both be frusto-conical and planar. 
     The liner may have a circular or polygonal periphery and the groove may extend to the circular or polygonal periphery of the liner. The liner may be comprised of metal. The explosive charge may be arranged to form the liner into a formed projectile in the shape of an annular ring upon a detonation thereof. The annular ring may be circular or polygonal. 
     The explosive charge may comprise a high explosive, which may be characterized as a material that detonates, meaning that the explosive shock front passes though the material at a supersonic speed (e.g. 3,000 to 9,000 meters/second). The high explosive charge may comprise an organic nitrate explosive, such as a nitramine explosive. 
     The shaped charge explosive device may further comprise a core plug, which may be encircled by the explosive charge, as well as a detonator, which may include a ring of detonators or an explosive shaped detonation train, and casing, which may be circular or polygonal, located to a rear of the explosive charge. The casing and the liner may be in the form of an enclosed tubular channel. 
     According to another object of the invention, a method of cutting a structure may be provided comprising the steps of providing a shaped charge device comprising an explosive charge, a liner lining a front of the explosive charge, the liner having a recess in the form of a groove encircling an axis of symmetry and the groove arranged to provide an axis of projection for the liner at an angle B relative to the axis of symmetry; detonating the explosive charge to create a detonation wave; forming the liner into an formed projectile in the shape of an annular ring with the detonation wave; directing the formed projectile towards the structure; and forming an annular ring cut pattern in the structure with the formed projectile. The formed projectile may be in the shape of an annular jet ring or slug ring. The annular ring cut pattern may be conical or a polygonal pyramid. 
     The method may further comprise the shaped charge explosive device having a core plug, and impacting a portion of the structure within the annular ring cut pattern with the core plug. 
     The structure may be targeted by a weapon containing the shaped charge explosive device. The weapon may comprise a rocket, missile, torpedo or other self-propelled bomb. The weapon may comprise a warhead and the structure may comprise a structure of an enclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features of this disclosure, and the manner of attaining them, will become more apparent and better understood by reference to the following description of embodiments described herein taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a shaped charge explosive device according to one embodiment of the present invention; 
         FIG. 2  is a cross-sectional perspective view of the shaped charge explosive device of  FIG. 1  taken along line 2-2; 
         FIG. 3  is a cross-sectional side view of the shaped charge explosive device of  FIG. 1  taken along line 2-2; 
         FIG. 4  is a cross-sectional side view of the shaped charge explosive device of  FIG. 1  taken along line 2-2 which further shows the formation of a jet ring and slug ring along with the formation of a ring shaped cut pattern in a structure; 
         FIG. 5  is a cross-sectional perspective view of a shaped charge explosive device according to another embodiment of the present invention; and 
         FIG. 6  is a side view of another embodiment of the shaped charge explosive device in a warhead of a self-propelled bomb. 
     
    
    
     DETAILED DESCRIPTION 
     It may be appreciated that the present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The embodiments herein may be capable of other embodiments and of being practiced or of being carried out in various ways. Also, it may be appreciated that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting as such may be understood by one of skill in the art. 
     Referring to  FIGS. 1 and 2 , a lined shaped charge explosive device is shown at reference character  10 . Explosive device  10  comprises a seamless circular liner  12 . Liner  12  may comprise materials such as metal, glass, ceramic or other suitable material. More particularly, metal liners may comprise aluminum, beryllium, cadmium, cobalt, copper, gold, lead, magnesium, molybdenum, nickel, platinum, silver, tantalum, tin, titanium, tungsten, depleted uranium, zinc and zirconium. Liner  12  may have a thickness in the range of and all increments between 0.5 millimeters to 12 millimeters, and more particularly in the range of and all increments between 2 millimeters to 6 millimeters. However, the thickness will depend on the overall scale. 
     Liner  12  has a circular indentation or recess in the form of a V-shaped circular groove  16  which encircles axis of symmetry  22  and may surround disc portion  26 , which can aid in the formation of a jet and slug as described below. However, in alternative embodiments, such as shown in  FIG. 5 , disc portion  26  may be eliminated. 
     Groove  16  has adjacent planar frusto-conical wall portions  18 ,  20  with front side surfaces which form a concave apex angle A as shown in  FIG. 3 . Concave angle A may be in the range of and all increments between 20 degrees to 140 degrees, more particularly in the range of and all increments between 30 degrees to 110 degrees, and even more particularly in the range of and all increments between 30 degrees to 90 degrees. 
     Liner  12  has a circular periphery  14  which overlies an adjacent edge  28  of casing  32  described in further detail below. For purposes of orientation herein, liner  12  is located to a front of device  10  while casing  32  is located to a rear of device  10 . 
     From circular periphery  14 , to form circular groove  18 , outer frusto-conical wall portion  18  may converge rearwardly relative to axis of symmetry  22  while inner frusto-conical wall portion  20  may diverge rearwardly relative to axis of symmetry  22 . With respect to one another, wall portions  18  and  20  converge rearwardly towards the apex  24  of groove  16 . As shown, the wall portions  18 ,  20  of liner  12  do not necessarily form an acute sharp angle at the apex  24  of angle A but rather are formed with a radius r in the range of and all increments between 1 millimeter to 8 millimeters. However, in alternative embodiments it should be recognized that wall portions  18 ,  20  may form a sharp angle. 
     At the mouth or opening of groove  16 , which is opposite apex  24 , outer frusto-conical wall portion  18  may terminate in a maximum outer diameter OD, which may define the circular periphery of 34 of liner  12 , in the range of and all increments between 25 millimeters to 300 millimeters, and more particularly in the range of and all increments between 50 millimeters to 150 millimeters. Also at the entrance to groove  16 , inner frusto-conical wall portion  20  may terminate in a minimum inner diameter ID in the range of and all increments between 5 millimeters to 250 millimeters, and more particularly in the range of and all increments between 20 millimeters to 100 millimeters. 
     Beneath liner  12  is located an annular ring shaped explosive charge  30 , which is located between liner  12  and casing  32 . Explosive charge  30  may comprise a high explosive, which may be characterized as a material that detonates, meaning that the explosive shock front passes though the material at a supersonic speed (e.g. 3,000 to 9,000 meters/second). The high explosive charge may comprise an organic nitrate explosive, such as a nitramine explosive. The explosive charge may also comprise nitroaromatics (e.g. 2,4,6-trinitrotoluene; 1,3,5-trinitrobenzene; 2,4-dinitrotoluene; 2,6-dinitrotoluene). 
     More particularly, the explosive charge  30  may comprise 1,3,5-trinitroperhydro-1,3,5-triazine, which may also be known by the variants RDX; cyclonite; hexogen; T4; hexahydro-1,3,5-trinitro-1,3,5 triazine; 1,3,5-trinitro-1,3,5-triazacyclohexane and cyclotrimethylenetrinitramine. 
     The explosive charge  30  may also comprise a plastic or putty explosive, which is hand malleable, such as composition  4 , or C 4 , which includes approximately 91% 1,3,5-trinitroperhydro-1,3,5-triazine; 6% plasticizer (e.g. diethylhexyl or dioctyl sebacate) and 2% plastic binder (e.g. polyisobutylene) by weight. 
     The explosive charge  30  may also comprise 1,3,5,7-tetranitro-1,3,5,7-tetrazocane, which may also be known by the variants HMX; cyclotetramethylene-tetranitramine; tetrahexamine tetranitramine and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocane. 
     The explosive charge  30  may also comprise a polymer-bonded explosive, which, in contrast to a plastic explosive, is not hand malleable after curing, such as LX-14, which includes approximately 96% 1,3,5,7-tetranitro-1,3,5,7-tetrazocane and 4% polymer binders (e.g. estane &amp; 5702-F1) by weight. 
     Casing  32  provides a backer or support structure to explosive device  10  to direct the energy of explosive charge  30 . Casing  32  is shown to be cylindrical around outer surface  34  and further comprises inner concave surfaces  36 ,  38  which form a bowl-like circular recess wall structure around axis of symmetry  22 , and provide surfaces to form the shape of explosive charge  30 . 
     Also between liner  12  and casing  32  is a centrally located elongated core plug  40  which is centered on the axis of symmetry  22  and surrounded by explosive charge  30 . Core plug  40  and explosive charge  30  are located in and occupy the circular recess formed by casing  32  and the cavity formed between casing  32  and overlying liner  12 . Core plug  40  provides surfaces  42 ,  44  which oppose surfaces  36 ,  38  of casing  32  to provide a symmetrical annular shape to explosive charge  30 . In alternative embodiments, as shown in  FIG. 5 , core plug  40  can be eliminated. 
     As shown in  FIG. 3 , groove  16  and explosive charge  30  are arranged to provide a projection axis or axis of projection  52 , which, in the present embodiment, bisects apex angle A equally. As shown, axis of projection  52  is at an angle B relative to axis of symmetry  22 . Angle B, which may be referred to as the projectile angle or angle of projection relative to the axis of symmetry  22 , is in the range of and all increments between 1 degree to 45 degrees, more particularly in the range of and all increments between 2 degrees to 20 degrees, and even more particularly in the range of and all increments between 5 degrees to 15 degrees. 
     When device  10  is detonated, the explosive charge is set off by detonator  50  located to the rear of device  10  on the axis of projection  52  creates a shock wave produced by the detonation front. In various embodiments, detonator  50  may comprise a single detonator, a ring of detonators or an explosive shaped detonation train. As the shock wave progresses from the apex  24  towards the opening of the groove  16 , the shock wave compresses the liner  12 . As shown in  FIG. 4 , under the pressure of the shock wave, the liner  12  collapses and protrudes towards the axis of projection  52 , which results in the formation of a forward jet ring  60  and slower moving rearward slug ring  62 . From the shape of groove  16 , the jet ring  60  and the slow moving slug ring  62  form the shape of an enclosed annular ring, which mimics the shape of the groove. Thus, if the shape of the groove  16  is circular or oval, for example, the shape of the jet ring  60  and slug ring  62  may be expected to be circular or oval, respectively. 
     Once the jet ring  60  and/or slug ring  62  make contact with the desired structure  64 , the ring  60 ,  62  may be configured to cut into the structure  64  to provide a cutting tool in the form of a cutting ring. For example, if the structure  64  comprises a shell (e.g. outer shell of (1) a building, bunker or other fortification, such as a door, side wall, floor or roof thereof; or (2) a vehicle which may travel by land, water or air (e.g. a tank, ship, submarine or airplane) such as armor, a hull or a fuselage thereof; or (3) a weapon or other munition; or (4) any protective enclosure), the jet ring  60  and slug ring  62  may be configured to cut through the wall structure to provide a ring shaped cut pattern  66  therein, as shown in cross-section in  FIG. 4 . In this manner, the explosive device functions as a hole saw. 
     The ring shaped cut pattern  66  may provide an aperture in the structure  64 . However, in certain instances, the aperture may be at least partially occluded by a resulting obstruction portion  68  of the structure  64  formed and defined by the rings  60 ,  62  as the cutting is performed. 
     In the event the ring shaped cut pattern  66  creates an aperture which is occluded by an obstruction portion  68  of the structure  64 , within the path defined by the confines of the jet ring  60  or slug ring  62  may be located core plug  40  which may travel at a speed slower than the jet ring  60  and the slug ring  62 . Thus after the jet ring  60  and slug ring  62  has formed the ring shaped cut pattern  66 , and an obstruction portion  68  of the structure  64  may now exists within the confines of the resulting aperture, the core plug  40  may now impact the obstruction portion  68  and eject it from the aperture. In the even there is no plug  40 , the center obstruction  68  may still ne removed by blast over pressure from the explosive  30  detonation. 
     Now, given that the jet ring  60  and slug ring  62  travel along the angle of projection B relative to the axis of symmetry  22 , the ring shaped cut pattern  66  will tend to be in the form a frusto-conical ring shaped cut pattern  66  which enlarges in diameter as it progresses through the structure  64  from a point of entry  70  to a point of exit  72 . Thus, any obstruction  68  in the aperture may also take on a frusto-conical shape. Given that the fact that the frusto-conical shape of the obstruction will enlarge from the point of entry  70  to point of exit  72  of the jet ring  60  and slug ring  62 , it may be easier for the core plug  40  to eject or remove the obstruction  68  from the structure  64  than if the ring shaped cut pattern  66  were simply cylindrical, which may be expected to occur if the angle of projection B of the explosively formed projectile was parallel with the axis of symmetry  22 . 
     In an alternative embodiment, as shown in the cross-sectional view of  FIG. 5 , explosive device  10  may have a polygonal shape, and in particular polygonal liner  12 , polygonal groove  16 , polygonal explosive charge  30  and polygonal casing  32 . More specifically, as shown in  FIG. 5 , the polygonal shape is an octagon. In other embodiments, the polygonal shape may be a trigon, tetragon (square), pentagon, hexagon, heptagon, nonagon, decagon, hendecagon or dodecagon. In contrast to the preceding embodiment, the explosive device  10  of  FIG. 5  will create a polygonal annular ring (as opposed to a circular annular ring), and have a cut pattern which is a polygonal pyramid (as opposed to conical), with the number of sides corresponding to the number of sides of the explosive device  10 . 
     As shown in  FIG. 6 , the explosive device  10  may be utilized as a warhead in a missile, rocket, torpedo or other self-propelled bomb  80  having an aerodynamic cover or nose cone  82 . In other embodiments, explosive  10  may be used as a static (stationary) device and not as part of a self-propelled bomb. As also shown in  FIG. 6 , casing  32  may comprise a tubular channel. 
     Also as shown in  FIG. 6 , self-propelled bomb  80  may include a secondary device  84 , which may comprise another explosive charge configured to detonate after the charge  30  has detonated, or a sensing device, such as a device capable of sensing a weapon of mass destruction, such as a nuclear weapon. 
     The shaped charges disclosed herein may be used in various types of military ordnance, such as weapons and munitions including warheads (explosive material and detonator delivered by rocket, missile, torpedo or other self-propelled bomb), gun-fired projectiles and mines. The shaped charges may also be used breeching devices to breach a structure, such as provide an opening to gain entry to the structure or to weaken the structure (e.g. demolition of a building). The shaped charges may also be used an initial breech device for a secondary device (e.g. tandem warhead). 
     While a preferred embodiment of the present invention has been described, it should be understood that various changes, adaptations and modifications can be made therein without departing from the spirit of the invention and the scope of the appended claims. 
     The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. Furthermore, it should be understood that the appended claims do not necessarily comprise the broadest scope of the invention which the Applicant is entitled to claim, or the only manner(s) in which the invention may be claimed, or that all recited features are necessary.