Abstract:
An apparatus for protecting a vehicle having a body from a rocket-propelled grenade (RPG), comprising a panel comprised of a plurality of spaced, generally parallel bars positioned in spaced outward relation to said body of said vehicle.

Description:
CROSS REFERENCE TO RELATED CASE 
       [0001]    The present invention is related to and claims the benefit of PCT/US2007/17108 filed Jul. 31, 2007 and of U.S. Provisional patent application No. 60/834,389, filed on Jul. 31, 2006, and entitled “Apparatus And Method For The Protection Of A Vehicle From Rocket-Propelled Grenades (RPGs).” 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field Of The Invention 
         [0003]    The present invention relates to armaments and more particularly to apparatus and methods for the protection of a vehicle from a rocket-propelled grenade (RPG). 
         [0004]    2. Brief Description Of Prior Developments 
         [0005]    RPGs are a class of generally shoulder-fired weapons having a shaped explosive charge and which are propelled by a rocket against heavily armored, lightly armored, and unarmored vehicles, bunkers or other fortified positions, and other targets. 
         [0006]    Because the shaped explosive charge concentrates the force of the detonated explosive, RPGs are a serious threat to both armored and unarmored vehicles. The prior art suggests a number of methods and apparatus, either active of passive, which may be effective in providing protection for vehicles from RPGs. Several previous passive methods have utilized arrays of round steel bars or slats. However these apparatus are too heavy for many vehicles, do not achieve full effectiveness in protecting the vehicle and its occupants, suffer extensive damage after an encounter, and are difficult to repair and maintain. 
         [0007]    A need, therefore, still exists for an improved highly effective, light weight, low cost apparatus and method for the protection for vehicles from RPGs. 
       SUMMARY OF INVENTION 
       [0008]    The present invention is an apparatus for protecting a vehicle having a body from a rocket-propelled grenade (RPG), comprising one or more panels comprised of a plurality of spaced, generally parallel bars positioned in spaced outward relation to said body of said vehicle. 
         [0009]    The present invention also encompasses a method for protecting a vehicle having a body from a rocket-propelled grenade (RPG) comprising the step of positioning one or more panels composed of a plurality of spaced generally parallel bars in spaced outward relation to said vehicle. The panels are designed to achieve maximum theoretical effectiveness while minimizing weight, damage to the adjacent structure, and operational interferences while simplifying repair. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention is further described with reference to the accompanying drawings wherein: 
           [0011]      FIG. 1  is a perspective view of a vehicle equipped with the RPG defense system of the present invention; 
           [0012]      FIG. 2  is a side-elevational view of a vehicle equipped with the RPG defense system shown in  FIG. 1 ; 
           [0013]      FIG. 3   a  and  FIG. 3   b  are views of the vehicle shown in  FIG. 2  in which the RPG defense system is shown respectively in its deployed and its collapsed position; and 
           [0014]      FIG. 4  is a schematic drawing showing the operation of the system of the present invention to cause the shaped explosive charge in an RPG to be disabled from detonating. 
           [0015]      FIGS. 5A-5D  depict illustrative embodiments of a bushing according to one embodiment of the invention. 
           [0016]      FIG. 6A  depicts an illustrative embodiment of fencing employing multiple panels to completely surround a vehicle according to one embodiment of the invention. 
           [0017]      FIG. 6B  depicts an illustrative embodiment of fencing employing multiple panels to completely surround a vehicle according to one embodiment of the invention. 
           [0018]      FIGS. 7A and 7B  depict a hinge according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]    Referring to  FIGS. 1 and 2 , there is shown a vehicle  10  with a body  12 . The vehicle  10  shown is a military Humvee utility vehicle, but it will be understood by those skilled in the art that the system of this invention may be adapted for use on military engineering vehicles as well as on many other types of heavily or lightly armored military vehicles or unarmored military vehicles or on civilian vehicles. On one side of the vehicle there is a front door  14  and a rear door  16 . On the opposed side of the vehicle  10  there is also a front door  18  and a side door  20 . Spaced outwardly from the doors  14 ,  16 ,  18  and  20  there are respectively panels  22 ,  24 ,  26  and  28 . 
         [0020]    Referring, for example, to panel  22 , each of the panels includes a plurality of spaced, parallel horizontal bars as at horizontal bars  30  and  32 . As will be described in greater detail below, each of these horizontal bars, as at bars  30  and  32 , is preferably cross sectionally square or otherwise cross sectionally rectangular or otherwise has at least one angular feature on its outer side, including a triangular or other polygonal shape. According to one embodiment, the horizontal bars are implemented as ½ inch square high strength aluminum alloy bars with a 2¾ inch spacing between horizontal bars, although other sizes and spacings may be used, including a 3″ spacing. Additionally, other materials may be used, such as steel, carbon fiber, and/or high strength aluminum alloys, including 7075-T6 aluminum. 
         [0021]    Each of the horizontal bars is attached to two spaced parallel vertical bars  34  and  36 , which may be spaced at apart at regular or irregular amounts. According to one embodiment, the spacing may be in the range of 16 inches to 36 inches, though smaller or larger spacings may be used. The panels are each also suspended from four horizontal posts as at posts  36 ,  40 ,  42  and  44  in the case of panel  22 . The panel  22  is also pivotally attached to the posts. For example, post  38  is attached to the body  12  at pivot  46  and is attached to the panel  22  at pivot  48 . The horizontal bars may be deployed at a distance from the vehicle to permit sufficient breakup of the RPG prior to impact with the vehicle. The range of spacing from the outside of the vehicle can be a long as desired. In general it should not be too close to the vehicle. According to one embodiment of the invention, the spacing between the horizontal bars and the vehicle is between 8-12 inches. A larger spacing may be used. 
         [0022]    In addition to the protection provided by the horizontal and vertical bar modular fencing sections, further protection may be provided by providing a shock attenuating backup layer on the outside of the vehicle. The layer may be comprised of metal or a composite honeycomb, multi-layer fiber reinforced polymer matrix composites, such as Kevlar (Aramid fibers), Spectra or Dyneema (polyethelyne fibers). This attenuation layer may be used to attenuate peak pressure in the explosive caused by collision of an RPG with the vehicle surface, which decreases the probability of initiation of a high order rapid deflagration of the residual explosive. The shock attenuating backup layer may not be required on vehicles already equipped with heavy armor plates. 
         [0023]    As is shown in  FIGS. 3   a  and  3   b , the panels as, for example, panels  22  and  24  may be pivotable upwardly and inwardly from the lower deployed position, respectively at  50  and  52  to upper collapsed positions  54  and  56 , respectively. It will be understood that the upper collapsed positions  54  and  56  provided a reduced transverse dimension to allow easier maneuvering of the vehicle  10  in, for example, tight spaces. The collapsible feature of the invention also allows for easier stage and transport of the vehicle with which the system is used. There is also a one-inch aluminum honeycomb attenuator  58  over the armored vehicle doors. This additional attenuator and the armor works with the system of this invention to protect the vehicle occupants from the duded RPG impact and blast effects. 
         [0024]    The vertical members may also be secured to a horizontal portion of the vehicle, or other portions of the vehicle, without a pivotal connection. This may be particularly useful for portions of the vehicle that do not need to be accessed regularly, such as the front or rear portions of the vehicle or non-doored side portions of the vehicle. 
         [0025]    According to one embodiment of the invention, the horizontal bars are secured to the vertical bars using bushings. The bushings help to prevent or minimize rotation of the horizontal bars upon RPG impact and permit deformation and movement of a horizontal bar through the vertical support upon impact with a RPG, blast debris, or fragments. This serves to minimize transfer of load and subsequent deformation and damage of the vertical support members and overall structure. According to one embodiment, the bushings are designed to break away, during impact, to further reduce transfer of impact loads to support structure. This may be accomplished by using a material that is strong enough to withstand vehicle operation loads but less strong than the vertical and horizontal members. Examples include polymer materials such as Delrin, Nylon, or other injection moldable or castable plastics. 
         [0026]    One embodiment of a bushing is shown in  FIGS. 5A-5D . Referring to  FIG. 5A , the bushing  500  includes an inner cavity that fits around a horizontal bar. The inner cavity accommodates the shape of the horizontal bar to facilitate attachment to it. In addition, the vertical bars may include features to facilitate attachment of the bushings, including holes, including D shaped holes. According to one embodiment, the inner cavity is a ½ inch square and fits around ½ inch square horizontal bars. Each horizontal bar is inserted through the inner hole in the bushing and is secured only by friction. In one embodiment stop screws (ADD- FIG. 3   a  and  3   b,  ##) inserted near the ends of each horizontal bar are employed to prevent the bars from shifting horizontally during operation and to secure the bushings to the vertical member. In another embodiment, clamps on the protuding length of selected horizontal bars, adjacent to and outside the vertical member, may be used to stabilize the assembly. 
         [0027]    To facilitate deployment, according to one embodiment of the invention, sets of the horizontal and vertical bars may be made to accommodate particular vehicles or multiple vehicles. The sets may be configured to have the same cross sections, so that multiple horizontal and vertical members and bushings may be stocked in predetermined lengths so that when they break as a result of a RPG or other incident, the broken pieces may be removed and new pieces put in place. This allows for 80-90% commonality of hardware and assemblies between different vehicles. Each vehicle may require different attachment members to pivotally connect modular fencing sections of horizontal and vertical bars to the vehicle or to secure the modular fencing sections without a pivotal connection to other parts of a vehicle. Additional sections may be attached with hinged sections to permit the effective width of the vehicle to be reduced when maneuvering in tight quarters. This also facilitates crew ingress and egress and access to parts of the vehicle that need frequent access. 
         [0028]      FIGS. 7A and 7B  depict a hinge according to an embodiment of the present invention. Referring to  FIGS. 7A and 7B , the hinge includes hinges  700 , a hinge spring plate  710 , a pin hinge  720 , a cotter pin  730 , a flat washer  740 , a hinge spring  750  and bolts and nuts  760 . The hinges  700  are U shaped and attach to one another via the pin hinge  720  and cotter pin. A pair of hinge spring plates attach to the hinges and are used to secure the hinge spring  750 . The bolts and nuts are used to secure the hinge spring plate to the hinges. The hinges themselves attach to the vehicle and to horizontal or vertical bars to facilitate opening and closing of sections of fencing. The hinges may be attached using any of the techniques referenced herein. It will be understood that beyond pins and nuts and bolts, other fasteners and fastening techniques and pivotal connections may be used. For example, detents, rivets, welding, adhesive, screws and/or other techniques may be used. 
         [0029]    According to one embodiment of the invention, the modular fencing system is mechanically assembled and does not require any welding, thus eliminating softening of a heat treated vehicle hull and/ or armor plates, which tends to reduce blast protection capability of a hull. Rather, the fencing sections are secured to a vehicle using bolts. Beyond bolts, other fasteners or fastening techniques may be used, including clamps, removable pins, utilizing either ball dentents or cotter pins, allow easy securing of the fencing sections to the vehicle and release of hinged doors or total removal of selected sections where required. 
         [0030]      FIGS. 6A and 6B  are illustrative views of additional vehicles with modular fencing systems according to embodiments of the present invention. 
       Operation 
       [0031]    Referring to  FIG. 4 , the operation of the RPG defense system of the present invention is shown. An RPG is shown generally at  60  and includes a piezoelectric nose initiator  62 , an outer ogive  64 , an inner ogive  66 , a shaped charge cone  68 , a shaped explosive charge  70 , and a base detonator  72 . The system of the present invention which interacts with the PRG includes a horizontal bar  74  which is cross sectionally square and which has consequently outer angular features  76  and  78 . As described above the system also includes other spaced, parallel horizontal bars as at bar  80  which is also cross sectionally square and which consequently has outer angular features  82  and  84 . 
         [0032]    As is conventional, when an RPG hits a target (not shown) the piezoelectric nose initiator  62  would produce an electric current which would be transmitted to the detonator  72  which detonates the explosive charge  70 . In the case shown in  FIG. 4 , however, the outer ogive  64  contacts angular feature  82  of horizontal bar  80  so as to deform the outer ogive  64  to cause it to contact inner ogive  66  to short-circuit current produced at piezoelectric nose initiator  62  and thereby disable the means for detonating the explosive  70 . 
         [0033]    It will be appreciated that a lightweight, low-cost and effective RPG defense system for lightly armored and engineering vehicles as well as other vehicles which operates by disabling the RPG shaped charge electronic fusing circuit has been described. This system also works with the existing vehicle armor and optional attenuation to protect occupants from RPG impact and blast effects. The system is also field installable and maintainable. The system may also be made removal or collapsible. The system will also have a minimal effect on driver visibility. 
         [0034]    While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications or additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.