Abstract:
A modular hand grenade design that permits the use of compressed powders such as A-5. The hand grenade body is split into two main components—a base/sleeve and a nose cap. These two main components contain the explosive. They are loaded with explosive while still separate. The explosive is loaded into the base/sleeve and compressed to form a solid. A core sleeve is attached to the base to form a void inside the explosive where the detonating portion of a fuse assembly can be placed. Explosive is likewise loaded into the nose cap and compressed to form a solid. The nose cap is attached to the base/sleeve assembly. A fuse assembly is then attached to complete the grenade.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to the field of munitions. More specifically, the invention comprises a hand grenade with a modular design allowing the components to be easily varied in order to suit particular objectives. 
         [0003]    2. Description of the Related Art 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The present invention comprises a modular hand grenade design that permits the use of compressed powders such as A-5. The hand grenade body is split into two main components—a base/sleeve and a nose cap. These two main components contain the explosive. They are loaded with explosive while still separate. The explosive is loaded into the base/sleeve and compressed to form a solid. A core sleeve is attached to the base to form a void inside the explosive where the detonating portion of a fuse assembly can be placed. Explosive is likewise loaded into the nose cap and compressed to form a solid. The nose cap is attached to the base/sleeve assembly. A fuse assembly is then attached to complete the grenade. 
         [0005]    Different types of nose caps can be provided to allow the grenade to be reconfigured in the field. A shaped charge nose cap allows the grenade to perform armor piercing operations. A detonator nose cap allows the grenade to be remotely detonated using an electrical signal. Many other variations are possible using the inventive design. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view, showing a complete hand grenade made according to the present invention. 
           [0007]      FIG. 2  is a sectional elevation view, sowing internal details. 
           [0008]      FIG. 3  is an exploded perspective view, showing the major components of the present invention in a disassembled state. 
           [0009]      FIG. 4  is a perspective view, showing the nose cap. 
           [0010]      FIG. 5  is a sectional elevation view of the nose cap of  FIG. 4 . 
           [0011]      FIG. 6  is a sectional detail view, showing the wall of the nose cap. 
           [0012]      FIG. 7  is a perspective view, showing the base. 
           [0013]      FIG. 8  is a sectional elevation view of the base of  FIG. 7 . 
           [0014]      FIG. 9  is a sectional detail view, showing the wall of the base. 
           [0015]      FIG. 10  is a perspective view, showing the sleeve. 
           [0016]      FIG. 11  is a perspective view, showing the sleeve from another vantage point. 
           [0017]      FIG. 12  is a sectional detail view, showing the wall of the sleeve. 
           [0018]      FIG. 13  is a perspective view, showing the core sleeve. 
           [0019]      FIG. 14  is an elevation view, showing the fuse assembly. 
           [0020]      FIG. 15  is a sectional elevation view, showing the assembly process. 
           [0021]      FIG. 16  is a sectional elevation view, showing an alternate nose cap incorporating a shaped charge. 
           [0022]      FIG. 17  is a sectional elevation view, showing an alternate nose cap incorporating an electrical detonator. 
       
    
    
       [0023]      
         [0000]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                 REFERENCE NUMERALS IN THE DRAWINGS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 hand grenade 
                 12 
                 fuse assembly 
               
               
                 14 
                 body 
                 15 
                 safety clip 
               
               
                 16 
                 pin 
                 18 
                 pull ring 
               
               
                 20 
                 safety lever 
                 22 
                 nose cap 
               
               
                 24 
                 base 
                 26 
                 sleeve 
               
               
                 28 
                 core sleeve 
                 30 
                 explosive 
               
               
                 32 
                 explosive 
                 34 
                 joint 
               
               
                 36 
                 male thread 
                 38 
                 female thread 
               
               
                 40 
                 male thread 
                 42 
                 latitude channel 
               
               
                 44 
                 longitude channel 
                 46 
                 flat 
               
               
                 48 
                 panel 
                 50 
                 female thread 
               
               
                 52 
                 outer mating face 
                 54 
                 wall 
               
               
                 56 
                 fuse receiver 
                 58 
                 boss 
               
               
                 60 
                 inner mating face 
                 62 
                 wall 
               
               
                 64 
                 nose cap receiver 
                 66 
                 base receiver 
               
               
                 68 
                 female thread 
                 70 
                 wall 
               
               
                 72 
                 core sleeve 
                 74 
                 flange 
               
               
                 76 
                 mating surface 
                 78 
                 tube 
               
               
                 80 
                 hollow interior 
                 82 
                 detonator 
               
               
                 84 
                 male thread 
                 86 
                 mating surface 
               
               
                 88 
                 delay element 
                 90 
                 gasket seat 
               
               
                 92 
                 locating pin 
                 94 
                 holding fixture 
               
               
                 96 
                 holding fixture 
                 98 
                 shaped charge nose cap 
               
               
                 100 
                 copper cup 
                 102 
                 detonator nose cap 
               
               
                 104 
                 detonator 
               
               
                   
               
             
          
         
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0024]      FIG. 1  shows hand grenade  10  in an assembled state. Body  14  contains explosive and is designed to rupture into fragments upon detonation. The body includes the novel elements of the invention. It is preferably attached to a conventional fuse assembly  12 . The fuse assembly includes pin  16  connected to pull ring  18 . The pin secures safety lever  20  in the “safe” position as shown. Safety clip  15  prevents unintentional deployment of the safety lever. The fuse components are well understood by those skilled in the art. Several existing fuses may be adapted for use with the invention, including the M213 fuse assembly currently being used by the United States Army. 
         [0025]    Body  14  is formed by combined three separate components.  FIG. 2  is a sectional elevation view through the hand grenade—illustrating how the three separate components are combined. Sleeve  26  is a hollow cylinder having female threads at either end. Nose cap  22 —which is equipped with corresponding male threads—screws into the first end of the sleeve. Base  24 —which is also equipped with corresponding male threads—screws into the second end of the sleeve. Of course, one could also create a design in which male threads are provided on the sleeve and female threads are provided on the nose cap and base. 
         [0026]    Cores sleeve  28  is mated against the interior of base  24 . It provides a housing for the inwardly protruding portion of fuse assembly  12  and keeps the fuse assembly separate from explosive  32 . Explosive  30  is loaded into nose cap  22 , with the two volumes of explosive meeting at joint  34 . 
         [0027]    A variety of explosives can be used, but A5 (a combination of RDX and wax) is preferred. Those skilled in the art will know that A5 must generally be pressed into place. The present design is particularly well suited to the use of A5—as will be explained subsequently. 
         [0028]      FIG. 3  shows an exploded perspective view of the components illustrated in  FIG. 2 . Nose cap includes male thread  36  which is sized to engage female thread  38  on a first end of sleeve  26 . Core sleeve  28  fits inside sleeve  26 . Base  24  is equipped with male thread  40  which engages a female thread on the second end of sleeve  26 . Fuse assembly  12  screws into base  24  in still another threaded engagement. 
         [0029]    The nose cap, sleeve, and base are preferably made of a strong and dense material such as steel. Core sleeve  28  is preferably made of a thin and ductile material such as copper. The fuse assembly is made of a variety of materials known to those skilled in the art. 
         [0030]      FIG. 4  shows a perspective view of nose cap  22 . All the components making up the body of the grenade are preferably provided with features which will cause the grenade to fragment in a predictable way. One way to accomplish this is to provide a series of channels in the interior or exterior surfaces. In the embodiment shown in  FIG. 4 , a series of channels are provided in the exterior surface of the nose cap. A plurality of longitude channels  44  intersect a plurality of latitude channels  42  in order to divide the exterior surface into a plurality of panels  48 . When the grenade detonates, the nose cap will tend to fragment along these channels and thereby break into fragments that are approximately the size of the individual panels  48 . Flat  46  may be provided on the nose cap as well. 
         [0031]      FIG. 5  shows a sectional elevation view through the nose cap. The reader will observe how latitude channels  42  reduce the thickness of wall  54 —thereby creating a local weakness which tends to promote fracture upon detonation.  FIG. 6  shows this feature in greater detail. Since the channels are provided on an exterior surface, they may easily be cut by a machining process. They may also be cast into the nose cap if a casting process is used. 
         [0032]      FIG. 7  depicts base  24  in a perspective view. Fuse receiver  56  is a hole sized to receive fuse assembly  12 . It includes female thread  50  (which engages a corresponding male thread on the fuse assembly. Outer mating face  52  surrounds the fuse receiver. When the fuse assembly is installed, an inward facing face of the fuse assembly bears against outer mating face  52  to form a seal. A seal enhancing feature is preferably included. In the embodiment shown, gasket seat  90  is provided. It retains an elastic O-ring which forms a positive seal with the fuse assembly. As for the nose cap, base  24  includes a plurality of latitude channels  42  and longitude channels  44  which divide its exterior surface into a plurality of panels  48 . 
         [0033]      FIG. 8  shows a sectional elevation view through base  24 . The reader will observe how fuse receiver  56  passes through from the exterior surface to the interior surface. Inner mating face  60  is positioned to bear against the core sleeve—as will be explained subsequently. Gasket seat  90  is provided in a flat upstanding boss  58 . Male thread  40  is provided to engage the female thread on the second end of sleeve  26 .  FIG. 9  shows a detail of wall  62  of base  24 —illustrating how the channels (in this case lateral channel  42 ) create local reductions in wall thickness to provide predictable fragmentation. As for the nose cap, the base is preferably made of a dense and strong material such as steel. 
         [0034]      FIG. 10  is a perspective view of sleeve  26 . This is preferably made as a relatively thick-walled cylinder. The first end includes nose cap receiver  64 —featuring female thread  38 . The outer surface of sleeve  26  includes longitude channels  44  and latitude channels  42 . These divide the exterior into panels  48 . 
         [0035]      FIG. 11  shows the second end of sleeve  26 . Base receiver  66  is configured to attach to the base, and female thread  68  is provided for this purpose. The interior surface of sleeve  46  is preferably made smooth to facilitate the loading of the explosive.  FIG. 12  is a detailed sectional view, showing how the inclusion of the channels (in this case latitude channels  42 ) creates fracture lines in wall  70  of sleeve  26 . 
         [0036]      FIG. 13  shows core sleeve  72  in more detail. This component separates the igniter portion of the fuse from the explosive contained within the grenade. It is preferably of thin-walled construction so that it may be easily breached. The part is preferably drawn out of a ductile material such as copper. Tube  78  is drawn to an extended length. Flange  74  is provided so that mating surface  76  can bear against inner mating face  60  of base  24 . Hollow interior is sized to admit the relevant components of the fuse assembly. 
         [0037]      FIG. 14  is an elevation view showing more details of fuse assembly  12 . Mating surface  86  bears against the O-ring contained within gasket seat  90  of base  24 . Male thread  84  threads into female thread  50  in base  24 . Descending from the triggering portion of the fuse assembly is a column containing delay element  88  and detonator  82 . These extend into the interior of core sleeve  72  when the grenade is assembled. When the pin is pulled and the grenade is thrown, the delay element is triggered. It burns for an established interval (typically 5 seconds) before igniting detonator  82 . The detonator then ruptures the core sleeve and detonates the A5 within the grenade body. 
         [0038]    The unique construction of the invention lends itself to manufacturing. As mentioned previously, A5 must generally be pressed into place (as opposed to granular nitrocellulose powders which may be simply poured through an opening).  FIG. 15  shows a simplified representation of the A5 loading process. Base  24  is first attached to sleeve  26 . Holding fixture  94  is provided. It includes locating pin  92 . The sleeve and base assembly is placed in holding fixture  94 . Core sleeve  28  is then placed over locating pin  92 , which properly locates the core sleeve with respect to the rest of the grenade assembly. An adhesive or sealant can be used to secure the flange of the core sleeve to base  24 . 
         [0039]    Explosive  32  (preferably A5) is then introduced through the opening. The explosive is compressed—typically using a ram. Once compressed the explosive fuses into a solid mass. The assembly of base  24 , sleeve  26 , and cores sleeve  28  may then be lifted free of the holding fixture and its associated pin. Because the explosive has been fused into a solid mass, the components will remain in the position shown even after the assembly has been lifted free of locating pin  92 . 
         [0040]    The nose cap is also shown being loaded in holding fixture  96 . Flat  46  on the nose cap may be placed against the bottom of holding fixture  96  to positively locate the component. Explosive is then introduced and pressed into place. As for the sleeve/bases assembly, the explosive is preferably fused into a solid mass that will hold its shape once the nose cap is removed from holding fixture  96 . 
         [0041]    Separate holding fixtures are shown for the base/sleeve assembly and for the nose cap. A third fixturing device (locating pin  92 ) is provided for core sleeve  28 . Those skilled in the art will know that such fixtures can be combined into a single fixture. Thus, although a first holding fixture, second holding fixture, and third holding fixture are illustrated—these should not necessarily be thought of as separate items. 
         [0042]    The explosive pressing process produces a solid mass of A-5 in both the base/sleeve assembly and the nose cap. In some embodiments it is desirable to leave the nose cap and the base/sleeve assembly separate (for reasons that will be made apparent subsequently). The reader will observe that the compressed explosive within the base/sleeve assembly has an exposed surface (facing upward in the view). The compressed explosive within the nose cap also has an exposed surface facing upward. These exposed surfaces are preferably sealed so that moisture and other contaminants cannot enter the device prior to the mating of the nose cap to the rest of the hand grenade. 
         [0043]    Once the explosive is loaded, the nose cap and sleeve/base assembly may be threaded together.  FIG. 2  shows the two sub-assemblies joined together. Joint  34  is formed between the explosive within the nose cap and the explosive within the sleeve. It is preferable to eliminate any voids at this interface. Thus, filler material is preferably introduced at joint  34  during the assembly process. A two part epoxy is a suitable filler material. 
         [0044]    The modular nature of the device allows more many variations—particularly with the nose cap. The reader will observe that once the propellant has been pressed into place, the nose cap can be attached to or removed from the balance of the hand grenade. This allows for the use of different types of nose caps. Interchangeable nose caps are preferably provided, with the decision of which type to use being left to the soldier in the field. 
         [0045]      FIGS. 16 and 17  show two examples of the many types of nose caps which could be provided.  FIG. 16  shows shaped charge nose cap  98 . Copper cup  100  is provided to contain explosive  32  and form it into a desired shape. The nose cap is then attached to the balance of the grenade. When the grenade fires, the copper cup will be collapsed into a stream of plasma—as is understood by those knowledgeable in the field of munitions. This allows the grenade to penetrate thick metal plates and even armored vehicles. 
         [0046]      FIG. 17  shows another alternate nose cap—detonator nose cap  102 . This embodiment includes a detonator receiver configured to accommodate an electrically triggered detonator  104 . This nose cap is also screwed into the body of the grenade. It allows the user to place the grenade and remotely detonate it using an electrical signal. This embodiment also allows two or more grenades to be simultaneously detonated using an electrical signal. 
         [0047]    The embodiments of  FIGS. 16 and 17  can be factory-created variations. Of course, it may well be preferable to provide the soldier with the option of changing among a variety of nose caps in the field. If this option is provided, it is important to prevent moisture ingress into the body of the grenade. A seal is therefore preferably provided over the exposed surface of the explosive in the nose cap and the explosive contained within the balance of the grenade. An example is a foil seal attached over each volume of explosive. This would allow the nose cap to remain off the body of the grenade without causing problems. 
         [0048]    The modular nature of the grenade allows for many other variations. Returning to  FIG. 2 , the reader will note that the overall length of the grenade may be varied by varying the length of sleeve  26 . This would vary the volume of explosive within the grenade and the resulting blast and fragmentation radius. A short version can be made to reduce the blast radius. 
         [0049]    The grenade as pictured in  FIG. 2  is relatively compact compared to the existing M67 hand grenade in present use. This results in part from the ability to use A5 explosive rather than the Comp B explosive used in the M67. The M67 is a spherical container that is loaded through a relatively small opening in the top. Comp B is a low melting-point material which can be poured through this opening. It would not be possible to load A5 into the M67, however, because it would not be possible to press it into place. 
         [0050]    The use of the A5 in place of Comp B allows either (1) a much more powerful grenade having similar dimensions; or (2) a comparably powerful grenade having significantly smaller dimensions. The present grenade is relatively slender—having a diameter of about 1.5 inches (or 37 mm). An M67 has a diameter of about 2.5 inches (or 67 mm). The reduced diameter allows a soldier having a smaller hand to more easily grip and throw the grenade. In addition, the slender configuration allows the present invention to more easily be carried in a pocket or other holding device on a tactical vest. 
         [0051]    The illustrations show the use of an existing fuse assembly with a safety handle configured for use with the M67 grenade. The reader will observe in  FIG. 2  that the safety handle could be reconfigured to lie more closely along sleeve  26 . Such an alternate embodiment could easily be provided and this would further enhance the ergonomics of the design. The current “safety clip” is likely to be replaced by a new “confidence clip” and the design is compatible with that feature as well. 
         [0052]    The preferred use of the machined channels on the exterior surface of the components allows the channel spacing to be altered without requiring expensive dedicated tooling. It is simple to use a lathe, a broach, or a grinding device to create the channels. The channel variation allows the size of the fragments produced upon detonation to be varied as desired. 
         [0053]    The reader will thereby appreciate that the present invention provides a modular hand grenade design with numerous advantages over the existing designs. The foregoing description and drawings comprise illustrative embodiments of the present invention. Having thus described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only, and that various other alternatives, adaptations, and modifications may be made within the scope of the present invention. Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Accordingly, the present invention is not limited to the specific embodiments illustrated herein, but is limited only by the following claims.