The subject invention relates to ordinance shielding.
Rocket propelled grenades (RPGs) and other ordinance are used by terrorist groups to target military vehicles and structures. See WO 2006/134407 incorporated herein by this reference.
Others skilled in the art have designed intercept vehicles which deploy a net or a structure in the path of an RPG in an attempt to change its trajectory. See U.S. Pat. Nos. 7,190,304; 6,957,602; 5,578,784; and 7,328,644 all incorporated herein by this reference. Related prior art discloses the idea of deploying an airbag (U.S. Pat. No. 6,029,558) or a barrier (U.S. Pat. No. 6,279,499) in the trajectory path of a munition to deflect it. These references are also included herein by this reference.
Many such systems require detection of the RPG and deployment of the intercept vehicle quickly and correctly into the trajectory path of the RPG.
Static armor such as shown in U.S. Pat. Nos. 5,170,690; 5,191,166; 5,333,532; 4,928,575; and WO 2006/134,407 is often heavy and time consuming to install. When a significant amount of weight is added to a HMMWV, for example, it can become difficult to maneuver and top heavy. Such an armor equipped vehicle also burns an excessive amount of fuel.
Moreover, known static systems do not prevent detonation of the RPG. One exception is the steel grille armor of WO 2006/134,407 which is said to destroy and interrupt the electrical energy produced by the piezoelectric crystal in the firing head of the RPG. Bar/slat armor is also designed to dud an RPG. But, bar/slat armor is also very heavy. Often, a vehicle designed to be carried by a specific class of aircraft cannot be carried when outfitted with bar/slat armor. Also, if the bar/slat armor is hit with a strike, the RPG still detonates. Bar/slat armor, if damaged, can block doors, windows, and access hatches of a vehicle.
Chain link fence type shields have also been added to vehicles. The chain link fencing, however, is not sufficiently compliant to prevent detonation of an RPG if it strikes the fencing material. Chain like fencing, although lighter than bar/slat armor, is still fairly heavy. Neither bar/slat armor nor the chain link fence type shield is easy to install and remove.
Despite the technology described in the above prior art, Rocket Propelled Grenades (RPGs) and other threats used by enemy forces and insurgents remain a serious threat to troops on the battlefield, on city streets, and on country roads. RPG weapons are relatively inexpensive and widely available throughout the world. There are varieties of RPG warhead types, but the most prolific are the PG-7 and PG-7M which employ a focus blast or shaped charge warhead capable of penetrating considerable armor even if the warhead is detonated at standoffs up to 10 meters from a vehicle. A perfect hit with a shaped charge can penetrate a 12 inch thick steel plate. RPGs pose a persistent deadly threat to moving ground vehicles and stationary structures such as security check points.
Heavily armored, lightly armored, and unarmored vehicles have been proven vulnerable to the RPG shaped charge. Pick-up trucks, HMMWV's, 2½ ton trucks, 5 ton trucks, light armor vehicles, and M118 armored personnel carriers are frequently defeated by a single RPG shot. Even heavily armored vehicles such as the M1 Abrams Tank have been felled by a single RPG shot. The PG-7 and PG-7M are the most prolific class of warheads, accounting for a reported 90% of the engagements. RPG-18s have been reported as well, accounting for a significant remainder of the threat encounters. Close engagements 30 meters away occur in less than 0.25 seconds and an impact speed ranging from 120-180 m/s. Engagements at 100 meters will reach a target in approximately 1.0 second and at impact speeds approaching 300 m/s.
The RPG-7 is in general use in Africa, Asia, and the Middle East and weapon caches are found in random locations making them available to the inexperienced insurgent. Today, the RPG threat in Iraq is present at every turn and caches have been found under bridges, in pickup trucks, buried by the road sides, and even in churches.
Armor plating on a vehicle does not always protect the occupants in the case of an RPG impact and no known countermeasure has proven effective. Systems designed to intercept and destroy an incoming threat are ineffective and/or expensive, complex, and unreliable.
Pending U.S. patent application Ser. No. 11/351,130 filed Feb. 8, 2006, incorporated herein by this reference, discloses a novel vehicle protection system. The following reflects an enhancement to such a system.
In accordance with one aspect of the subject invention, a new vehicle and structure shield is provided which, in one specific version, is inexpensive, lightweight, easy to install and remove (even in the field), easy to adapt to a variety of platforms, effective, and exhibits a low vehicle signature. Various other embodiments are within the scope of the subject invention.
The subject invention results from the realization, in part, that a new vehicle and structure shield, in one specific example, features a plurality of spaced rods held in position via the nodes of a net and used to dud an RPG or other threat allowing the frame for the net to be lightweight and inexpensive and also easily attached to and removed from a vehicle or structure.
The subject invention features a vehicle and structure shield comprising a flexible net subsystem including an array of rods or hard points supported by the net subsystem and configured to impact a projectile striking the net. A frame including mounting brackets attached thereto positions the frame in a spaced relationship with respect to the vehicle or structure. A first releasable fastener subsystem releasably secures the net subsystem to the frame. A second releasable fastener subsystem releasably secures the mounting brackets of the frame to a vehicle or structure.
In one example, the net subsystem includes first and second spaced nets having nodes interconnected by the rods. In this design, each rod may include a base portion with castellations for the first net and post portion extending from the base portion and also including castellations for the second net.
In another design, the net subsystem includes a single net and the rods each include a post portion and a base portion with a cavity receiving the post portion therein. In one example, the rods include a multi-sided portion defining sharp corners. In one version, there are six sides and six sharp corners. The multi-sided portion may include a cavity frictionally receiving a plug therein and a wall with longitudinal slots therein for the chords of a net.
In one embodiment, the frame may include telescoping members. Typically, the first releasable fastener subsystem includes hook type fasteners on the frame and loop type fasteners on the periphery of the net and the second releasable fastener subsystem includes loop type fasteners on the frame mounting brackets and hook type fasteners on patches securable to the vehicle or structure. The second releasable fastener subsystem may further include straps extending from the frame to the vehicle or structure.
One vehicle and structure shield in accordance with the subject invention includes a net with chords intersecting at nodes and a hard point for at least select nodes. One preferred hard point includes a multi-sided portion defining sharp corners, a cavity therein for a net node, and a plug received in the cavity locking the net node therein. The chords are preferably configured with a compliance which prevents detonation of a munition striking a chord.
One shield system in accordance with the subject invention features a flexible net including chords intersecting at nodes, a hard point for at least select nodes, a frame including mounting brackets positioning the frame in a spaced relationship with a vehicle or structure, a first releasable fastener subsystem releasably securing the net to the frame, and a second releasable fastener subsystem releasably securing the mounting brackets of the frame to the vehicle or structure. The chords of the net are configured with compliance which prevents detonation of an RPG striking a chord.
The subject invention also features a method of protecting a vehicle or structure. One preferred method includes choosing a net mesh size to maximize the effectiveness of the net against the munition striking in the net. Hard points are designed to maximize their effectiveness against a munition striking the net. The hard points are attached to at least select nodes of the net and the net is attached to a frame itself attached to a vehicle or structure supporting the net at a predetermined distance from the vehicle or structure. Attaching the net to the frame and attaching the frame to the vehicle or structure may include using hook and loop fasteners.
The typical net mesh size is between 110 mm and 180 mm. The preferred hard points weight between 10 and 40 grams, are between ½ inch to ¾ inches across, between ½ inch to 1 inch tall, and are multi-sided. The frame is designed to space the net between 4 and 24 inches from the vehicle or structure.
The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.
Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:
Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment. Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer.
Preferably, net subsystem 10 is removeably secured to frame 16 and frame 16 is removeably secured to vehicle 20,
As shown in
Manufacturing of a net with hard points in accordance with the subject invention is thus simplified. A net node is placed in cavity 70′,
There are trade offs in the design of the hard points and also the net. The aspect ratio of the hard points, their size, center of gravity, mass, and the like all play an important role. Hard points which are too large, for example, and a net mesh size which is too small results in too much surface area to be stricken by an RPG, possibly detonating the RPG. Hard points which are too small may not sufficiently damage the RPG ogive and dud the RPG. Steel is a good material choice for the hard points because steel is less expensive. Tungsten, on the other hand, may be used because it is heavier and denser, but tungsten is more expensive. Other materials are possible. The hard points may weigh between 10 and 40 grams and be ½ inch to ¾ inches across and between 0.5 inches and 1 inch tall.
It is preferred that the net node is placed at the center of gravity at the hard point. The length of the hard point is preferably chosen so that when an RPG strikes the net, the hard point tumbles 90 degrees and digs into the RPG ogive. The moment of inertia of the hard point is designed accordingly. In still other designs, the hard point may have more or less than six sides. The hard points may weigh between 10 to 40 grams although in testing 20 to 30 grams was found to be optimal.
The net material may be polyester which provides resistance to stretching, ultraviolet radiation resistance, and durability in the field. Kevlar may also be used. A knotted net is preferred. The chord diameter may be 1.7 to 1.9 mm. The typical net mesh size may be 176 mm (e.g., a square opening 88 mm by 88 mm) for a PG-7V RPG and 122 mm for a PG-7 VM model RPG. But, depending on the design, the net mesh size may range from between 110 and 180 mm.
The preferred spacing or standoff from the net to the vehicle is between 4 and 24 inches but may be between 4 and 60 centimeters. Larger standoffs may extend the footprint of the vehicle and thus be undesirable. Too close a spacing may not insure closing of the electrical circuitry of the RPG ogive by the hard points. The frame and mounting brackets are designed to result in the desired spacing.
It is desirable that the net material and mesh size be chosen and the net designed such that an RPG ogive, upon striking a net chord, does not detonate. RPGs are designed to detonate at a certain impact force. Preferably, the breaking strength of the net chord material is around 240 lbs so that an RPG, upon striking a net chord or chords, does not detonate. The net is thus designed to be compliant enough so that it does not cause detonation of the RPG. Instead, the hard points dig into the RPG ogive and dud the RPG before it strikes the vehicle or structure.
This design is in sharp contrast to a much more rigid chain link fence style shield which causes detonation of the RPG if the RPG strikes a wire of the fence. The overall result of the subject invention is a design with more available surface area where duding occurs as opposed to detonation.
When an RPG nose or ogive 90,
In one embodiment, the frame members are made of light weight aluminum. One complete shield with the net attached weighed 1.8 lbs. The shield is thus lightweight and easy to assemble, attach, and remove. If a given shield is damaged, it can be easily replaced in the field. The rods connected to the net cell nodes are configured to angle inwardly when an RPG strikes the net. This action defeats the RPG by duding it since the electronics associated with the explosives of the RPG are shorted as the rods impact or tear through the outer skin of the RPG ogive.
The result, in one preferred embodiment is an inexpensive and light weight shielding system which is easy to install and remove. The shields can be adapted to a variety of platforms and provide an effective way to prevent the occupants of the vehicle or the structure from injury or death resulting from RPGs or other ordinances. When used in connection with vehicles, the shield of the subject invention exhibits a low vehicle signature since it extends only a few inches from the vehicle.
The system of the subject invention is expected to meet or exceed the effectiveness of bar/slat armor and yet the flexible net style shield of the subject invention is much lighter, lower in cost, and easier to install and remove. The system of the subject invention is also expected to meet or exceed the effectiveness of chain link fence style shields and yet the net/hard point design of the subject invention is lower in cost, lighter and easier to install and remove.
Although specific features of the invention are shown in some drawings and not in others, however, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments.
In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant can not be expected to describe certain insubstantial substitutes for any claim element amended.
Other embodiments will occur to those skilled in the art and are within the following claims.
This application hereby claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/124,428, filed on Apr. 16, 2008 under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. §1.55 and §1.78.
Number | Date | Country | |
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61124428 | Apr 2008 | US |