Abstract:
An armor configuration has a curtain of overlapped plates of steel in close fitting flexible pockets disposed in front of, and temporarily displacable into, a space. The pockets hold the plates in overlapped alignment and the armor configuration has, inside the space, a space-filling resiliently compressible material. The armor configuration optionally has ballistic material backing layer behind the space.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent application 61/768,274 filed Feb. 22, 2013. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to protective equipment and personal armor; more particularly it relates to layered armor configurations. 
       BACKGROUND 
       [0003]    Conventional armor is heavy, especially steel armor, and further especially if it must stop high velocity ballistic threats such as armor-piercing rounds. What is needed is an armor to stop high velocity ballistic threats such as armor-piercing rounds at the lightest possible weight. It is known that steel, particularly various armor-grade steels, have great resistance to penetration by high velocity projectile rounds. With the proliferation of various armor piercing (AP) specialty rounds, still greater resistance to such penetration is being sought; and yet weight of such protection remains of primary importance. 
         [0004]    In some conventional armor configurations, various armor plating such as steel or ceramic are backed by some kind of dense foam to absorb back face deformations and to reduce trauma to the wearer. Such foam allows for only negligible displacement of the armor plate itself. 
         [0005]    Various overlapped steel or ceramic armor plating is known, particularly in the area of body armor. Whether body armor or vehicle armor is being discussed however, greatest penetration resistance at least weight is still the priority, followed closely of course by least cost. 
         [0006]    Some known armor configurations are as follows. One proposal is to have overlapping ceramic tiles glued to a multilayered ballistic cloth stack, with a dense foam cushion behind the ballistic cloth, between the armor and the wearer to hold the tiles in place upon impact by a projectile. Another proposal is to have overlapped platelets on a supporting fabric which can include 1/16 to ⅛ inch of a relatively hard (shore A 42-55) foamed vinyl plastisol. A third proposal is to have a series of overlapped or specially jointed protective plates inserted into pockets of a carrier material, with an inner layer of plates of a thick, dense material such as polyamide. Yet another proposal is to have armor panels comprising multi-hardened plates arranged in multiple layers on a fabric backing with optional rubber inserts in the pockets. In all of these proposals, the material behind the protective plates is aimed at preventing backward displacement of the armor upon projectile impact, to protect the wearer from impact by movement of the plates. 
       DISCLOSURE 
       [0007]    Method and material are disclosed to stop high velocity ballistic threats such as armor-piercing rounds at the lightest possible weight and lowest cost. 
         [0008]    In a first embodiment, steel strips are overlapped in an armor configuration. An example is for a plurality of 3 inch wide, ¼ inch thick steel strips that are overlapped by ⅛ or ½ or even 1 inch. Strip widths and steel specifications vary with the requirements of the armor application in ways that will be appreciated by those skilled in the art. This overlapped steel strip configuration is generally not attached to any of its underlayers but preferably hangs more or less vertically from a hanger bar. Tests have shown that with ¼ inch steel, a configuration of angled steel strips in a curtain floating on, or hanging in front of, an air gap or a low density foam adds an additional 500 fps protection vs AP rounds, compared to use of steel that is not free to be displaced into a space behind the curtain of steel alone. 
         [0009]    This method of layering the strips also creates an advantage in a ballistic event because an armor surface at even a slight angle off vertical, say 10-15 degrees, will out-perform an armor surface that is perpendicular to the (generally horizontal) trajectory of the projectile. In disclosed applications, preferred arrangements of the armor configuration (such as body armor, or vehicle armor) will present most of the steel strip faces at a slight angle off the vertical. In particular embodiments, the angle off the vertical is such that the curtain of plates is inclined slightly toward the horizontal, rather than away from the horizontal. See  FIG. 1 . 
         [0010]    The overlapped steel strips are alternatively maintained in overlapped configuration by laminating them between two sheets of flexible capturing material such as rubberized cloth. A metal or aluminum or steel or composite material having a fiber and resin combination is an optional outside cover layer for the overlapped steel curtain strips. In this disclosure, directions like outside and inside are with reference to the approaching path of an anticipated projectile. Outside is what is first encountered by the projectile; inside is what is on the other side of the particular protective layer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a schematic illustration of overlapping plates. 
           [0012]      FIG. 2  is a schematic illustration of energy dissipation for the armor. 
           [0013]      FIG. 3  is a schematic illustration of overlapping plates. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In one example aluminum skins are pressed under hydrostatic pressure and formed into the shape of the overlapped or tiled metal. When mixed with an adhesive resin, this protects them from blunt impact. 
         [0015]    In each embodiment disclosed, the curtain (also sometimes referred to herein as a strike layer) is disposed to physically defeat the projectile. This can be a composite, or steel, or aluminum, or a ceramic hybrid, or any combination thereof. The strike layer is desirably constructed in such a way that it is at least semi flexible, or in other words, readily displacable into a space immediately behind it. Tiles, scales strips or plates may be used in this layer, and they may be overlapping or not overlapping. They are disposed in the curtain in such a way that a strip or plate, when impacted by a projectile, is free to be displaced temporarily backward into a space inside of or behind the curtain. Behind the air gap or foam-filled space, a semi flexible ballistic resistant material is optionally inserted or layered as a backing layer to catch any penetrating projectile fragments. 
         [0016]    In an alternate embodiment, a special shaped, semi rounded “fish scale” is used where strips would otherwise be used in the first two examples above. See  FIG. 3 . The scale design is optimized to reduce weight from excess overlapping of tiles while preventing any more vulnerable openings along scale edges. These scales may be laid at constant angles or random angles. 
         [0017]    In one embodiment, ballistic ceramic tiles are laid up and suspended in a stretchy, flexible rubber cast matrix or a composite wrapping. These tiles are laid on an angle where each tile overlaps the next like a tilted domino stack. The ballistic ceramic tiles can also be wrapped in fiber composite and pressed in a boroclave or other HIP press to create a fully encapsulated ceramic tile solution. This wrapping improves the ceramics ability to “stand and fight” by trapping a striking projectile&#39;s energy in the space of the tile, and obviating the disadvantage of an otherwise brittle conventional tile. 
         [0018]    In a variant of embodiments 1 and 2 above, a row of continuous loops is sewn onto a backing material. The loop material and the backing material may be the same material or different, and either or both materials can be ballistic cloth. The loops are shaped and disposed such that each loop will contain one each steel strip, and when the strips are fully inserted in the respective loops, the loop material is a tight fit on the strip, and the loops hold the strips in the desired overlapped configuration. See  FIG. 1 . 
         [0019]    It is to be noted that advantageously the steel is not glued or otherwise fastened to anything; rather they float freely outside of, or on top of, the space, whether the space is empty and filled with air, or with a layer of relatively low-density foam. The disclosed space with optional foam is just behind the overlapped steel strips or the steel strips and their cloth pockets. When the space is filled with foam, it is desirably in a continuous layer, rather than a layer of separate foam platelets. The foam is resilient and preferably has only negligible ballistic resistance of its own. 
         [0020]      FIG. 1  illustrates a general layered armor configuration  10  as discussed above, with overlapping steel strips  12  separated from optional ballistic backing layer  11  by layer of space  13  that is optionally foam-filled. Tiles or strips  12  may be individually wrapped in cloth loops  3  which are desirably formed by sewing seams  5  onto backing layer  14 , where one strip is inserted into each loop, and where the loop is sized to closely fit the selected strip. Each loop  3  is thus filled by insertion of the respective strip, and the elongated loops hold the strips in a desired overlapping configuration. Steel  12 , or steel strips  12  wrapped in loops  3  hang vertically from hanger bar  7 . 
         [0021]    In some embodiments, flexible ballistic resistant material is optionally layered behind steel strips  12  and used as the backing  14  for the loop material  3 . 
         [0022]      FIG. 2  is a schematic illustration of the temporary displacement of steel strip  12  into the air gap or foam-filled space  13 . The schematic is divided into four rapidly sequenced time phases 1 through 4. In phase 1, projectile  6  strikes steel  12  and, before the projectile can deform or begin to penetrate the steel, and steel  12  is displaced a bit in phase 2 into space  13 . At phase 3 there is further displacement of steel  12  into space  13 , and still there is no appreciable deformation or penetration of the steel by the projectile. Finally at phase 4, the steel has reached maximum displacement and the projectile is shattered and deformed by the steel, as the steel itself is deformed and partially penetrated by the remains of the projectile, with ballistic backing  11  catching any fragments. 
         [0023]    In a phase subsequent to phase 4 (not illustrated) steel strip  12  returns (under the influence of gravity, or with assistance by resilient foam) to its regular hanging position illustrated in phase 1. It should be noted that the schematic is on its side for ease of time phase explanation, though in practice the steel  12  hangs more or less vertically, or as discussed above, at an angle just off the vertical. 
         [0024]      FIG. 3  illustrates a general pattern for an overlapping scale armor of the type discussed above. 
         [0025]    With regard to systems and components above referred to, but not otherwise specified or described in detail herein, the workings and specifications of such systems and components and the manner in which they may be made or assembled or used, both cooperatively with each other and with the other elements of the invention described herein to effect the purposes herein disclosed, are all believed to be well within the knowledge of those skilled in the art. No concerted attempt to repeat here what is generally known to the artisan has therefore been made.