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Patent application title: BAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES

Inventors:  William R. Kellner, Jr. (Lovettsville, VA, US)  Paul C. Dickson (San Diego, CA, US)  Paul W. Trester (Encinitas, CA, US)
Assignees:  GENERAL ATOMICS
IPC8 Class: AF41H700FI
USPC Class: 89 3608
Class name: Shields transportable self-propelled, e.g., tanks, etc.)
Publication date: 2011-09-29
Patent application number: 20110232472



Abstract:

A bar armor system is provided for reducing damage caused by RPGs launched towards a vehicle. The bar armor system includes at least one bar array, comprised of lateral bars and vertical bars, wherein the lateral bars are set in predetermined positions so as to reduce the possibility of shaped charges being directed towards the target vehicle. Tubular shaft retainers are provided to be positioned in annular openings in the vertical bars. The lateral bars can be of a round or hexagonal cross-section, and when hexagonal lateral bars are employed, the flat surfaces of the cross-section are positioned horizontally by the tubular shaft retainers so as to minimize the area presented to an oncoming RPG, particularly when the RPG strikes at a non-normal incidence. Push washers can be employed at the outside surfaces of the vertical bars so as to hold them in position. A mounting system is provided that is capable of positioning the bar armor system at close distances to the vehicle so that the overall size and weight of the vehicle is not unduly increased by the bar armor system. The mounts can include rotary latches to provide easy installation and removal. The system can also be of an electrically-conductive unified composition so that efficient electrostatic coating techniques can be used to cover the system. The system can also be provided in the form of kits for ready installation and for more economical repair.

Claims:

1. Bar armor system for protecting a vehicle from rocket-propelled grenades, comprising: at least one bar array; said bar array being comprised of: a plurality of lateral bars, said lateral bars being either round or hexagonal in cross-section; at least two vertical bars, each having a plurality of annular openings; and a plurality of tubular shaft retainers disposed in said annular openings of said vertical bars for receiving said lateral bars and for locating said lateral bars in a predetermined position; and mounts for mounting said bar array to said vehicle.

2. The bar armor system of claim 1, wherein said tubular shaft retainers are comprised of a spring steel alloy containing, by weight, between about 0.3% and about 0.8% carbon.

3. The bar armor system of claim 1, wherein said lateral bars are round in cross-section and have a yield strength of at least about 100 ksi.

4. The bar armor system of claim 1, wherein said lateral bars are hexagonal in cross-section and have a yield strength of at least about 93 ksi.

5. The bar armor system of claim 1, wherein said lateral bars are approximately 5/16ths of an inch in diameter.

6. The bar armor system of claim 1, wherein said lateral bars are hexagonal in cross-section, wherein two flat faces of the cross-section are oriented substantially horizontally.

7. The bar armor system of claim 1, wherein said lateral bars are each spaced apart at a distance less than about 57 mm.

8. The bar armor system of claim 1, wherein said lateral bars are each spaced apart at a distance of approximately 53 mm.

9. The bar armor system of claim 1, wherein said lateral bars are comprised of a steel alloy with greater than 2% uniform plastic deformation up to ultimate tensile strength and a total elongation to failure of not less than 5%.

10. The bar armor system of claim 9, wherein said steel alloy is selected from the group consisting of: AISI 1144 steel and AISI 41L40 steel.

11. The bar armor system of claim 1, wherein said bar array further comprises at least two push washers disposed on at least one of said lateral bars abutting at least one of said vertical bars.

12. The bar armor system of claim 11, wherein said bar array has a top and a bottom, and said push washers are disposed on the lateral bars second from top and second from bottom of said bar array.

13. The bar armor system of claim 1, wherein each of said mounts comprises a bracket.

14. The bar armor system of claim 13, wherein at least one of said brackets further comprises a rotary latch.

15. The bar armor system of claim 1, wherein said mounts position said lateral bars at a standoff distance of less than about 9 inches from the vehicle.

16. The bar armor system of claim 1, wherein said mounts position said lateral bars at a standoff distance of approximately 7.5 inches from the vehicle.

17. The bar armor system of claim 1, wherein said mounts attach to the vehicle magnetically.

18. The bar armor system of claim 1, wherein said bar array is approximately 3 feet wide.

19. The bar armor system of claim 1, wherein said vertical bars are substantially rectangular in cross-section.

20. The bar armor system of claim 1, wherein said vertical bars are approximately six feet in length, about one-half inch in width, and about one inch in depth.

21. The bar armor system of claim 1, wherein said vertical bars are comprised of a wrought aluminum alloy.

22. The bar armor system of claim 21, wherein said wrought aluminum alloy is 7075-T651 aluminum.

23. The bar armor system of claim 1, wherein each bar array is electrostatically coated.

24. The bar armor system of claim 23, wherein the electrostatic coating comprises a chemical agent resistant coating.

25. A kit for preparing a bar armor system comprising: at least two vertical bars, said vertical bars having a plurality of annular openings; a plurality of lateral bars, said lateral bars being either round or hexagonal in cross-section; a plurality of shaft retainers with an outer geometry adapted to be in registering relationship to said annular openings of said vertical bars and an inner geometry adapted to be in registering relationship to said lateral bars; said vertical bars, lateral bars, and shaft retainers operative to assemble into a bar array; and mounts for mounting said bar array to a vehicle.

26. The kit of claim 25, further comprising a plurality of push washers.

27. The kit of claim 25, wherein said mounts further comprise rotary latches.

28. The kit of claim 25, wherein said shaft retainers are already placed and oriented in said annular openings of said vertical bars.

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to bar armor. More particularly, this invention relates to bar armor systems for protecting a vehicle from rocket-propelled grenades.

[0003] 2. Description of Related Art

[0004] Shortly after rocket-propelled grenades ("RPGs") were used to attack vehicles, various forms of standoff armor arose to attempt to reduce the effectiveness of the RPGs. Towards the end of World War II, anti-vehicle infantry weapons came into wider use in response to the increasing use of tanks. To try to protect against these weapons, tank crews utilized a rudimentary form of standoff armor such as field-mounted bedsprings and/or screen doors positioned on the tank. Later, during the Vietnam War, additional forms of rudimentary standoff armor were employed, often comprised of scrap metal, screens, chicken wire, and chain-link fencing.

[0005] These rudimentary standoff armor systems were cumbersome and not very successful. The protection they attempted to afford was marginal at best. Generally, these systems merely attempted to cause the RPG to not strike a vehicle directly but to detonate away from the target. No attempt was made in these systems to prevent the RPG from detonating or to cause the RPG to do as little damage as possible upon detonation.

[0006] More recently, formal designs have been suggested to attempt to provide greater protection by reducing the chances of normal detonation of an RPG. General Dynamics has installed what it terms a "slat armor" system for a Stryker Armored Personnel Carrier ("APC"). This "slat armor" weighs approximately 5200 pounds and is quite cumbersome. Another system that has been suggested, produced by the company BAE Systems, uses a series of square aluminum bars, termed L-ROD®, for trying to protect vehicles such as the Buffalo and RG-31 in use by the United States military. Still another system has been employed by Canadian forces to retrofit the Leopard 2 tanks with a "slat armor" to help defend against RPGs. The Israeli military also began using a "slat armor" system in 2005 to help protect its heavily-modified Caterpillar D9R Armored Bulldozer against RPG attacks. Several of these later designs have operated by attempting to actually deaden the RPG by causing an electrical short in the RPG on impact.

[0007] While these later designs have offered some improvement over the earlier rudimentary systems, they have not been entirely successful, and have even raised additional difficulties. For example, although it is desirable to extend protection away from the vehicle, some of these systems appear to have extended the protection too far, resulting in increased size and weight and decreased maneuverability. The increase to vehicle dimensions also makes the vehicle unnecessarily more visible in the field, thereby causing additional danger to the occupants. These designs also have subjected the vehicle to increased wear and tear, and undue restriction in operations, such as in crowded urban environments, because of the increased size.

[0008] In addition, current systems also includes a lack of modularity in assembly and installation. For example, most current bar and slat armor systems are welded together and/or are welded directly to the vehicle, to provide the strength needed to defeat an RPG threat. Such welding is difficult and time-consuming. Additionally, when the welded designs break, a large portion of the bar or slat armor has to be replaced, rather than replacing only the damaged section. This is expensive, time-consuming, and decreases the time that the protected vehicle is available for field use.

[0009] While not all previously-designed systems have employed welding, even the non-welded systems have not been satisfactory. For example, some systems use non-conductive parts, such as plastic bushings, to assemble the armor systems. However, use of such parts can prevent a quick and efficient electrostatic coating and can instead require the use of wet paint, which is more expensive, less efficient, and more time-consuming.

[0010] Among the additional deficiencies in later designs is that they have not addressed the specific weapons sought to be defeated. As a result, these designs do not adequately address the detonation details and capabilities of current weaponry and the dynamics of RPG impact. It appears that, in the past, more attention has been given to the economy of using commercially available materials, such as reinforcing bars used in construction, than to considerations for increasing effectiveness to prevent the formation of the most damaging explosions by the RPG. Nor does it appear that earlier designs have given consideration to the dynamics and geometry of the bar armor systems themselves, and their components, to most effectively prevent formation of the most damaging explosions by RPGs.

[0011] Accordingly, it is an object of the present invention to provide a bar armor system that can reduce the damage caused by RPGs targeting a vehicle. It is another object of the invention to minimize the formation of the most damaging explosions caused by RPGs launched at a vehicle. It is a further object of the invention to maintain effective protection against RPGs without unduly extending the size or increasing the weight of the vehicle. It is another object of the invention to provide a bar armor system that can position lateral bars so they can offer better protection against an oncoming RPG. It is a further object of the invention to provide a bar armor design that can be readily installed and repaired. It is still another object of the invention to provide a bar armor system that can be produced in kits, which can facilitate efficient installation and repair. Additionally, it is an object of the invention to provide a bar armor system that can be made of electroconductive materials that can be electrostatically coated when fully assembled. These and other objects of the invention will become apparent from the following brief summary of the invention, drawing figures, detailed description, and claims.

BRIEF SUMMARY OF THE INVENTION

[0012] The present invention provides a bar armor for protecting a vehicle from rocket-propelled grenades. The bar armor comprises at least one bar array and mounts for mounting the bar arrays to the vehicle. The bar arrays are comprised of a plurality of lateral bars, which can be either round or hexagonal in cross-section; at least two vertical bars, each having a plurality of annular openings; and a plurality of tubular shaft retainers disposed in the annular openings of the vertical bars for receiving the lateral bars and for holding the lateral bars in a predetermined position.

[0013] The lateral bars are approximately 5/16'' in diameter (which, for hexagonal cross-section lateral bars, is measured across the flats) and can be spaced apart at a distance less than about 57 mm for particular RPG threats. The hexagonal lateral bars are oriented having two flat faces oriented substantially vertically so as to provide a better geometry for reducing RPG shaped charge detonation. The bar arrays can further comprise at least two push washers disposed on at least one of the lateral bars abutting at least one of the vertical bars to prevent translation of the vertical bars. The mounts can comprise a bracket, which can further comprise a rotary latch, adapted to work in conjunction with particular lateral bars. The mounts can position the lateral bars at a distance of less than about 9 inches from the vehicle. The invention also provides bar armor that can be installed in kits, for easy installation, repair, and replacement. The system is also adapted to be electrostatically coated, including with a chemical agent resistant coating ("CARC") to promote further efficiencies.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0014] FIG. 1 is an isometric view of the bar armor system of the invention mounted to a vehicle sought to be protected.

[0015] FIG. 2 is expanded view of an RPG partly in cross-section to show the various components of the RPG, including its inner and outer ogives and piezoelectric fuse.

[0016] FIG. 3 is an expanded view of an RPG partly in cross-section in the proximity of lateral bars, to show how the lateral bars can operate to crush the outer ogive into the inner ogive, thereby forming an electrical contact and creating an electrical short-circuit to prevent the formation of a shaped charge.

[0017] FIG. 4 is a view of an assembled bar array.

[0018] FIG. 5 is an inside view of a vertical bar to show shaft retainers placed in the annular opening receiving lateral bars.

[0019] FIG. 6 is a view of a vertical bar showing the positions of the annular openings.

[0020] FIG. 7 is an expanded view of a tubular shaft retainer and a push washer.

[0021] FIG. 8 shows an expanded view of a bar array mounted to a portion of a vehicle showing mounts.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The bar armor system of the present invention is adapted to minimize damage caused by rocket-propelled grenades ("RPGs") by reducing the incidence of shaped charges forming upon contact or near-contact with a vehicle sought to be protected. Shaped charges are directionally-oriented explosive detonations (i.e., combustions that propagate via self-sustaining supersonic shock waves) that have the particular effect and highest incidence in causing damage. Shaped charges can be very damaging. Depending on the particular RPG, a shaped charge can penetrate at least 30 cm into armored steel or more. It is unacceptable to attempt to combat shaped charges by simply increasing the thickness of the vehicle armor. The increased thickness would make the vehicle so massive and cumbersome that it could effectively render the vehicle immobile.

[0023] The present invention reduces the need for increased armor thicknesses by substantially reducing the risk of shaped charges causing damage to a targeted vehicle. Among the ways this is achieved is by causing the RPG to deflagrate (i.e., combust via subsonic thermal conductivity) rather than form a shaped charge upon detonation. When the RPG deflagrates, it may still travel at a significant velocity and can still explode into fragments. However because deflagration is subsonic and largely non-directional, it causes much less damage than does shaped charge detonation.

[0024] Referring to FIG. 1, the bar armor system 010 of the invention is positioned on vehicle 001 sought to be protected. Vehicle 001 can be any of a wide array of vehicles, such as a HMMWV or Humvee, Buffalo, RG-31, Mine-Resistant Ambush Protected ("MRAP") vehicles, FMTV (Family of Medium Tactical Vehicles), and others. As will be explained in more detail below, bar armor 010 can be assembled directly on vehicle 001 or can be provided in sections or in the form of kits.

[0025] The present invention protects against a wide array of RPGs. Among the most widely-used RPGs are the RPG-7 and the RPG-7m. Referring to FIG. 2, RPG 090 comprises a dual shell (ogive) and a piezoelectric fuse 091 that can deliver a voltage to detonator 094, designed to form a shaped charge in the direction of piezoelectric fuse 091. In general, these RPGs are comprised of an outer shell or outer ogive 092, and an inner shell or inner ogive 093. Outer ogive 092 and inner ogive 093 are, by design, electrically isolated from each other. In RPG 090, one end of the piezoelectric fuse is electrically coupled to the outer ogive 092 and the other end is electrically coupled to inner ogive 093. When piezoelectric fuse 091 hits a target, it compresses and creates a voltage differential across the fuse, which outer ogive 092 and inner ogive 093 carry to detonator 094, thereby forming a shaped charge.

[0026] It has previously been suggested that an effective way of preventing an RPG 090 from forming a shaped charge is by bringing outer ogive 092 and inner ogive 093 into sustained electrical contact, thereby creating an electrical short circuit that prevents a voltage differential from traveling to and triggering detonator 094. For an RPG launched towards a target, short-circuiting can be accomplished by crushing outer ogive 092 until it physically contacts and deforms inner ogive 093 before piezoelectric fuse 091 compresses upon hitting a target, as shown in FIG. 3. Advantageously, because RPG 090 is short-circuited, the RPG can cause less damage even if it passes through the bar armor and strikes the vehicle.

[0027] The present invention greatly increases the ability of the bar armor to reduce damage caused by RPG shaped charges by increasing the likelihood of short-circuiting. This is accomplished with a dynamically structured design that minimizes the points of contact upon which a RPG hit will result in the formation of a shaped charge, and maximizes the possible points of contact in which a RPG hit will result in crushing the ogives, thereby short-circuiting the RPG and stopping detonation.

[0028] The present invention, while adapted to be effective to defeat multiple types of RPGs, is dynamically and structurally designed so as to be most effective at defeating the detonation of particular RPGs or a particular family of RPGs. The bar armor of the invention takes into consideration the size and geometry of the particular RPG warhead 090; the speed or range of speeds over which the RPG is most likely to strike a target; the size, sensitivity, and location of the piezoelectric fuse 091; the size, thickness, material composition, and material strength of the outer ogive 092 and the inner ogive 093; and the dimensions and durability of the vehicle 001 that the bar armor protects.

[0029] Referring again to FIG. 1, according to one embodiment of the invention, bar armor 010 comprises a plurality of bar arrays 100 and a plurality of mounts 600 to attach bar arrays 100 to vehicle 001. At least one of the bar arrays 100 comprises a plurality of lateral bars 200, a plurality of shaft retainers 400 that receive lateral bars 200, and at least two vertical bars 300 having a plurality of annular openings 310 that receive shaft retainers 400 as shown in more detail in FIGS. 4 and 8.

[0030] Each bar array 100 provides a modular, standard-sized bar armor segment readily adaptable to protect multiple types and configurations of vehicles 001. A typical bar array 100 can be approximately 6 feet high and 3 feet wide depending on the number of bar arrays to be employed in protecting a particular vehicle. It will be understood that to protect other vehicles or portions of vehicles, and/or against other threats, bar array panels of various sizes and in various numbers can be used.

[0031] Referring to FIG. 4, bar array 100 comprises a number of lateral bars depending on the vehicle sought to be protected. In particular, a bar array can have anywhere from between approximately ten and fifty lateral bars with a distance spacing 220 between each bar and the next. Preferably between approximately twenty-five and thirty-five lateral bars, more preferably from between approximately twenty-eight to thirty-two lateral bars, and most preferably approximately thirty lateral bars can be used in a bar array 100.

[0032] The vertical bars can also vary in number. For a bar array having approximately 30 lateral bars, the bar array can use two vertical bars. As will be discussed in more detail below, the bar arrays can be provided in the form of a kit so that the bar armor can be readily transported and installed on the vehicles at the most convenient location for installation. In addition, it is contemplated that providing the bar armor in the form of discrete bar arrays permits removal, repair, and reinstallation of a particular bar array without removing the entire bar armor from the vehicle.

[0033] Referring to FIG. 4, among the advantages to the present invention is that the bar arrays are provided with spacing 220 between lateral bars 200 so that the bar armor can best combat a particular RPG threat. The lateral bars can be secured in such manner as to maintain position in even the most rigorous of circumstances, including difficult terrain, and even nearby explosion. Thus, referring to FIGS. 4 and 5, shaft retainers 400 are provided that can securely hold lateral bars 200 and vertical bars 300 in position relative to each other and relative to vehicle 001. Additionally, push washers 500 can be provided to maintain vertical bars 300 in optimal location and orientation.

[0034] As shown in FIGS. 4 and 5, at least one bar array 100 contains at least two vertical bars 300 having annular openings 310 at periodic intervals. Each of these annular openings 310 receives a shaft retainer 400, which in turn receives and holds lateral bar 200. Height 105 of the bar array 100 is determined by height 350 of the vertical bars 300. Width 115 of the bar array 100 is determined by length 230 of lateral bars 200. It is contemplated to use different numbers of lateral bars and vertical bars of appropriate dimensions and of an appropriate spacing best adapted to protect a particular vehicle from a particular RPG threat, or a portion of the vehicle to be protected.

[0035] As shown in FIG. 4, approximately 6-foot vertical bars can be combined with approximately 3-foot lateral bars to create a bar array 100 that is about 6 feet in height 105 and about 3 feet in width 115. In that implementation, a portion 235 of each of the lateral bars 200 extends past the vertical bar in the bar array 100 so as to prevent the vertical bars 300 from coming too close to the vertical bars of an adjacent bar array upon installation, which can unduly cause the risk of an RPG forming a shaped charge upon striking the vertical bars.

[0036] Referring to FIGS. 4 and 6, vertical bars 300 are provided with annular openings 310 for receiving shaft retainers 400 and keeping lateral bars 200 at a spacing 220 effective to defeat or attempting to defeat an RPG threat. Vertical bars 300, in concert with shaft retainers 400, constrain the vertical movement of lateral bars 200 such that an incoming RPG 090 can have its outer ogive 092 crushed into sustained electrical contact with inner ogive 093. Keeping lateral bars 200 at distance spacing 220 decreases the likelihood that an incoming RPG 090 will strike the bar armor in such manner that piezoelectric fuse 091 would compress and send a voltage differential to detonator 094, causing the formation of shaped charge sought to be avoided by the use of bar armor. Upon contact with RPG 090, this vertical constraint also avoids or attempts to avoid, lateral bars 200 from translating vertically to maintain the integrity of the overall bar armor system.

[0037] Vertical bars 300 are of dimensions appropriate to protect a vehicle 001 such that each vertical bar 300 covers all or a portion of the height of vehicle 001, as shown in FIG. 1. Each vertical bar 300 can be approximately 6 feet in height 350, 1/2 inch in width 360, and 1 inch in depth 370, with annular openings of about 0.35 to 0.41 inches in diameter, at approximately every 2.1 inches. However, other dimensions, spacings, and configurations of annular openings can be used as best adapted to protect a particular vehicle or a portion of a vehicle from a particular RPG threat.

[0038] Vertical bars 300 can be made of materials strong enough so that the bar armor can withstand a RPG hit on lateral bars 200 without vertical bars 300 undergoing undue plastic deformation. Thus, vertical bars 300 can be made from a wide variety of materials such as steel, aluminum, titanium, or others with the necessary strength, weight, and material characteristics. Preferably, vertical bars 300 can be made of a wrought aluminum alloy. More preferably, vertical bars 300 can be made of an age-hardenable grade of wrought aluminum alloy with high strength and ductility, such as 7075-T651 drawn, cold-finished, and stress-relieved aluminum bar stock with an ultimate tensile strength of 80 ksi and 8% elongation to failure.

[0039] Vertical bars 300 have, at predetermined intervals, annular openings 310 which are of such geometry as to be in registering relationship with outer geometry 421 of shaft retainers 400. As shown in FIGS. 4 and 5, annular openings 310 receive shaft retainers 400, which in turn hold lateral bars 200 in place. Annular openings 310 are spaced at predetermined distances in vertical bars 300. Preferably, annular openings 310 are substantially round and are spaced apart at a distance slightly less than distance spacing 220, such that lateral bars 200 will be spaced at distance 220 when located in shaft retainers.

[0040] The vertical bars are positioned relative to the lateral bars so as to provide sufficient restraining force to keep the lateral bars at distance spacing 220 in the event of an RPG hit. This, in turn, requires that vertical bars 300, as well, maintain their position. To implement this, push washers 500 can be placed on vertical bars 300 to provide a restraining force to assist keeping vertical bars 300 in their predetermined position and orientation. This can further prevent vertical bars 300 from spreading apart horizontally when the lateral bars 200 are hit by an RPG 090. As shown in FIG. 7, push washers 500 have an opening 523, an inner geometry 522 adapted to be in registering relation to lateral bars 200, and an outer geometry 521 to provide contact with vertical bars 300. Push washers 500 can slide over lateral bars 200 and abut vertical bars 300, as shown in FIG. 8.

[0041] Preferably, as shown in FIG. 4, bar array 100 comprising two vertical bars 300 can use four push washers 500, although varying numbers of push washers are also contemplated. Two of the push washers 500 are preferably located on lateral bars 200 second from the top and second from the bottom of the bar array and abutting outside faces 379 of each vertical bar 300. Push washers are strong enough to prevent translation of the vertical bars. They can be comprised of aluminum, steel, or titanium, sufficiently protected to resist corrosion. Preferably, they are comprised of zinc-coated spring steel.

[0042] Advantageously, the lateral bars in each bar array, are positioned and kept in positions so as to maximize protection from RPGs. If allowed to unduly translate from those positions, the lateral bars would be less effective because the lateral bars would no longer be at the predetermined spacing, areal profile, and position best suited to prevent a particular RPG from forming a shaped charge. Also, allowing undue rotation of the lateral bars reduces the effectiveness of the lateral bars in preventing shaped charge formation. Preferably, the shaft retainers' inner geometry operates to prevent undue rotation of the lateral bars. Preferably, the shaft retainers have a tubular outer dimension 421 and can have an inner geometry 422 adapted to fit in registering relation with lateral bars 200. The use of shaft retainers allows each bar array 100 to be quickly assembled by inserting lateral bar 200 into shaft retainer 400 located in annular opening 310 of vertical bar 300 without need for undue welding, bolting, screwing, or chemical lubricants, although some alternative uses of such means is also contemplated.

[0043] It is desirable to prevent the vertical bars from becoming unduly plastically deformed if the lateral bars are struck by an RPG. Among the advantages that the bar armor system 010 of the invention can provide is that the lateral bars are designed to deform and/or fracture upon being struck by an RPG, such that the vertical bars can remain substantially undamaged. In this event, prompt repair can be facilitated because the vertical bars (which attach to the mounts) can remain in place and only the damaged shaft retainers and damaged lateral bars would need to be replaced and/or repaired.

[0044] Shaft retainers 400 are strong enough to keep lateral bars 200 from translating or rotating during the use of the bar armor system. Shaft retainers can be made of any composition and dimensions capable of achieving the aforementioned results. Preferably, shaft retainers are made of metal, such as spring steel, or aluminum, titanium, or other steels sufficiently protected to resist corrosion. Most preferably, shaft retainers are composed of zinc-coated steel alloy, containing between about 0.3% and about 0.8% carbon by weight, sufficient to increase both yield and ultimate tensile strength substantially to a "spring steel quality" from the cold-working (i.e., plastic deformation) of the material in forming the shaft retainer.

[0045] Referring to FIGS. 1 and 4, lateral bars 200 are of sufficient stiffness, density, and yield strength to be able to crush outer ogive 092 into inner ogive 093 upon contact with an RPG 090. The lateral bars are also preferably as light as possible to reduce the weight of the bar armor system, assist in installation, minimize the negative impact that use of bar armor typically has on vehicle maneuverability and fuel efficiency, and reduce wear and tear on the vehicle components. Preferably, the lateral bars are comprised of a material of moderate-to-high yield strength. More preferably, lateral bars are comprised of any steel alloy with an associated 0.2% offset tensile yield strength not less than 93 ksi, which demonstrates appreciable (i.e., greater than 2%) uniform plastic deformation up to the ultimate tensile strength and a total elongation to failure of not less than 5%, such as 4130 steel. Most preferably, lateral bars have a 0.2% offset tensile yield strength of at least 100 ksi and are comprised of AISI 1144 cold-finished and stress-relieved alloy steel, AISI 41L40 cold-finished annealed alloy steel, or other steel alloy possessing similar material properties.

[0046] Lateral bars 200 in shaft retainers 400 in vertical bars 300 are separated by spacing 220. Spacing 220 is selected to be most effective in preventing particular RPG threats forming shaped charges. This spacing provides a low areal percent for direct contact by a RPG, especially when the RPG is travelling at an off-angle (i.e., not normal to the plane of the bar array). For the RPG-7 and RPG-7m, the spacing 220 between lateral bars 200 is less than about 57 mm, and is preferably approximately 53 mm. Preferably, lateral bars are approximately 5/16'' in diameter. The diameter of a cross-section of hexagonal lateral bar 205 is measured from flat 206 to the opposite flat 206 across the narrowest part of the cross-section. More preferably, lateral bars 200 are either round in cross-section 201 with a yield strength of at least about 100 ksi, or hexagonal in cross-section 205 with a yield strength of at least about 93 ksi.

[0047] Many cross-sectional geometries of lateral bars 200 can be effectively used to combat a particular RPG threat. Round cross-sections are rotation invariant, i.e., they present the same profile to an RPG threat upon any axial rotation of any degree. As such, directional orientation is not necessary for a round lateral bar 201.

[0048] As will be explained below with reference to a hexagonal cross-section 205, lateral bars of non-round cross-sectional geometries used against each RPG threat should be placed at the proper orientation most effective in combating that threat. Proper orientation will present the smallest amount of surface area towards an oncoming RPG threat.

[0049] As shown in FIG. 5, two edges 207 of cross-section of hexagonal lateral bar 205 are oriented horizontally, towards front 361 and back 369 of vertical bars 300, such that an edge 207 of hexagonal lateral bar 205 will extend as far as possible from vehicle 001 and its opposite edge 207 will extend as close as possible to the vehicle. This orientation of hexagonal lateral bars minimizes the area that bar array 100 presents to an incoming RPG 090, especially when the RPG is travelling at an off-angle (i.e., not normal to the plane of the bar array). Hexagonal lateral bars 205 are a common shape and do not require significant additional machining or special ordering. As such they are widely available and easily replaceable.

[0050] Referring again to FIGS. 1 and 3, to be effective against a RPG, the bar armor is mounted to a vehicle 001 at a standoff distance 620 away from vehicle 001.

[0051] However, large standoffs are not without their problems. A large standoff will place more weight further away from the vehicle's center of mass, thereby increasing its moment of inertia and decreasing the handling ability of the vehicle. A larger standoff will also increase the size and weight of the mounts. Additionally, a larger standoff will increase the profile and effective size of the vehicle. This will decrease the vehicle's mobility, prevent it from entering constricted environments, and make it easier to spot and target with hostile fire.

[0052] According to the present invention, the standoff to defeat the RPG-7 and RPG-7m is set at only about 7-7.5 inches from the exterior of the vehicle. This standoff minimizes the negative effect on handling, maneuverability, and vehicle profile while still allowing the lateral bars to form a contact between outer ogive 092 and inner ogive 093. While a distance of 7-7.5 inches is preferred, it will be understood that other standoff distances can be employed based on the configuration of the particular RPG threat sought to be defeated and the specific configuration parameters of the bar array used.

[0053] Mounts 600 operate to affix bar array 100 to a vehicle 001 at standoff distance 620, and are of sufficient strength and in sufficient quantity to support and retain the bar arrays 100 under a variety of conditions, including impact from an RPG. The mounts can be as lightweight and inexpensive as possible. Preferably, the mounts are also easy to use and operable for rapid installation and removal of a bar armor system pursuant to this invention. Most preferably, the mounts attach magnetically to the vehicle sought to be protected, which greatly enhances ease of use in the field.

[0054] Preferably, the present invention comprises at least two sets of mounts per bar array, a set of upper mounts and a set of lower mounts. The upper mounts can operate without a positive locking feature for simplicity and ease of installation. The lower mounts can operate in conjunction with a rotary latch to provide a quick and easily-obtained positive lock for an installed bar array 100.

[0055] As shown in FIG. 8, mounts 600 of this invention can further comprise brackets 610 to allow bar array 100 to attach to a vehicle without need for undue welding or cutting into the vehicle. Brackets 610 can further comprise rotary latches 615, which are adapted to quickly connect bar panel 100 to vehicle 001 and quickly disconnect bar array 100 from vehicle 001. The particular rotary latch used will depend on the cross-sectional geometry (e.g., round or hexagonal) and diameter of lateral bars 200. Rotary latches 615 are preferably located between brackets 610 and inner faces 371 of vertical bars 300. Rotary latches 615 are a common commercial item.

[0056] The bar array 100 of this invention can come assembled or semi-assembled in a kit ready for mounting on vehicle 001. The kit can comprise at least two vertical bars each having a plurality of annular openings, a plurality of lateral bars being either round or hexagonal in cross-section, a plurality of shaft retainers, and mounts for mounting said bar array. The kits can also comprise push washers and latches such as rotary latches. The kit can also include vertical bars wherein the shaft retainers are already positioned in the annular openings.

[0057] The bar array of this invention can be entirely electroconductive. This can enable the use of electrostatic coating techniques which are quicker and more efficient than wet paint methods. Preferably, the electrostatic coating comprises a chemical agent resistant coating.

[0058] As seen from the above, a bar armor system has been described which is effective in defeating or substantially defeating RPGs. The bar armor system of the invention does not unduly extend the size and weight of the vehicle. Advantageously, the system positions lateral bars to be most effective against RPGs and provides an arrangement wherein damaged parts can be replaced with a minimum of difficulty. The invention also facilitates installation and repair with minimum effort and enables electrostatic coating with maximum efficiency.

[0059] It should be understood that while the invention has been described with reference to preferred embodiments, other alternatives within the scope of the invention are contemplated, and the scope of the invention is to be limited only by the claims presented below.


Patent applications by GENERAL ATOMICS

Patent applications in class Self-propelled, e.g., tanks, etc.)

Patent applications in all subclasses Self-propelled, e.g., tanks, etc.)


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Images included with this patent application:
BAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and imageBAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and image
BAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and imageBAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and image
BAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and imageBAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and image
BAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and imageBAR ARMOR SYSTEM FOR PROTECTING AGAINST ROCKET-PROPELLED GRENADES diagram and image
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Top Inventors for class "Ordnance"
RankInventor's name
1David L. Hunn
2Jesus S. Gomez
3Thomas Mann
4John Carberry
5Kevin M. Klatte
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