The subject invention relates to ordnance shielding.
Rocket propelled grenades (RPGs) and other ordnance 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, RPG-69s, and RPG-7Ls 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.
Chain link fencing has been used in an attempt to dud RPGs by destroying the RPG nose cone. See. for example, DE 691,067. See also published U.S. Patent Application No. 2008/0164379. Others have proposed using netting to strangulate the RPG nose cone. See published U.S. Application No. 2009/0217811 and WO 2006/135432.
WO 2006/134407, insofar as it can be understood, discloses a protective grid with tooth shaped members. U.S. Pat. No. 6,311,605 discloses disruptive bodies secured to armor. The disruptive bodies are designed to penetrate into an interior region of a shaped charge to disrupt the formation of the jet. The shaped charge disclosed has a fuse/detonator mechanism in its tail end.
No known prior art, however, discloses a net supporting a spaced array of hard points at a set off distance from a vehicle or a structure wherein the hard points are designed to dig or tear into the nose cone of an RPG and dud it.
Pending U.S. Patent Application Publication No. 2009/0266227, incorporated herein by this reference, discloses a novel vehicle protection system. The following reflects an enhancement to such a system.
In the field, if a hard point net is placed over a door, window, or other means of ingress or egress, it can be a slow process to remove the net from the frame and open the door or window in order to enter or exit the vehicle or structure. The same is true if it is desirable to remove one or more hard point nets and their frames for maneuvers, staging operations, transportation of a vehicle, or the like. The tubular frame members also add some weight to the vehicle or structure. Also, the frame members, if struck by an RPG, may cause detonation of the RPG.
In various aspects of the invention, in some embodiments. ingress and egress are made easier and a lighter weight system is provided. The subject invention results from the at least partial realization that, in one preferred embodiment, hard point nets with one or more cables serving as the frame components allow easier ingress, egress, provide improved coverage, and results in a lighter weight system. When two adjacent nets share the same cable, hard point coverage is even further improved.
The invention, in one example, includes a shield comprising a net including hard points at select nodes of the net. One or more sides of the net include a plurality of cable guides such as eyelets and at least one cable under tension extends through the cable guides supporting the net.
One specific design, the eyelets include a peripheral groove for receiving a net chord therein, the hard points include a body portion with a cavity and a plug received in the cavity, and a net chord extends between the plug and the body portion, around the eyelet groove, and back between the plug and the body portion. Typically, the hard points include slots in the body portion for the net chords.
Besides the cable(s), the framis for the net may include a top cross bar for supporting the net. In one version, spaced top struts interconnect the top cross bar with the vehicle or structure. In one example, the top cross bar includes a tensioning mechanism for the cable.
If the vehicle or structure includes a door, both top struts can be connected to the door or, alternatively, one top strut can be connected to the door and one top strut can be connected to the vehicle or structure. In the later design, the top struts are preferably pivotable with respect to the top cross bar and with respect to the door or vehicle structure.
The framis for the net, in some examples, includes spaced bottom struts for opposing sides of the net. In one example, the bottom struts are foldable with respect to the vehicle or structure and/or include a shock absorbing device. In one version, each bottom strut is connected to a net cable but the net cable is removable from its associated bottom strut. In but one example, a pin is removably received in a bottom strut and connected to the net. In one design, a cable extends through cable guides at the top and bottom of a first side of the net, over to a second side of the net and through cable guides at the bottom and top of the second side, to the top of the net, then through cable guides at the middle on the second side, then to the bottom of the net, over to the first side of the net, through cable guides of at the middle of the first side of the net, and then to the top of the net.
In another example, a member is provided for tensioning sides of the net and typically resides between the net and the vehicle or structure.
In several examples, a tray on the vehicle or structure is provided for storing the net. Typically, there are cable guides on opposing sides of the net and spaced cables, one on each side of the net. An adjacent net can be provided with cable guides and a cable then extends through the cable guides of both nets.
The invention also features a shield comprising a net with opposing sides of the net including a plurality of cable guides for supporting the net when a cable is provided under tension through the cable guides on each side of the net.
A method of manufacturing a shield, in accordance with one example, includes running chords of a net through a body portion of a hard point, direction the chord to a cable guide, redirecting the chord back between through the body portion of the hard point; and forcing a plus into the body portion of the hard point locking the chord therein. Preferably, the net chord is directed about the cable guide.
The invention also features a method of manufacturing a shield comprising securing hard points at select nodes of a net, adding cable guides to one or more sides of the net, and providing at least one cable under tension through the cable guides to support the net in a spaced relation with respect to a vehicle or structure.
One method includes supporting the net by a top cross bar and interconnecting the top cross bar with the vehicle or structure using spaced top struts. The method may further comprise making the top struts foldable with respect to the vehicle or structure. The method typically includes tensioning at least one cable. A method may include supporting the net via spaced bottom struts, making the bottom struts foldable with respect to the vehicle or structure, and/or equipping each bottom strut with a shock absorbing device. A bottom fabric portion may be provided for the net.
In one method, a member is provided for tensioning sides of the net and typically the member is placed between the net and 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 a vehicle (e.g., a HMMWV vehicle). In one particular example, tubular frame members 22a-22d include hook type fasteners secured to the outside thereof and the fabric net periphery 24,
If the frame structure of
As shown in
Strut members 46a and 46b may also be designed to be easily removed from the vehicle structure via quick release pins and/or the like. Members 46 could also be pivotably attached to the vehicle or structure. Other means for securing the net to the one or more cables can also be used and there are other ways possible for tensioning the cables.
As shown more clearly in
Side walls 74a-74f,
In this specific design, the base portion 72 and plug were made of hardened steel (e.g., ASTM A108 alloy 12L14) and combined weighed between 10 and 80 grams. A base portion with more or less sides is also possible. For a six sided design, the area of face 76,
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 be 0.5 inch to 0.75 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 80 grams although in testing 60 grams was found to be optimal, e.g., a 30 gram base portion and a 30 gram plug. Hard points between 10 and 40 grams are typical.
The net material may be polyester which provides resistance to stretching, ultraviolet radiation resistance, and durability in the field. Kevlar or other engineered materials can be used. A knotted, knotless, braided, or ultracross net may be used. The chord diameter may be 1.7 to 1.9 mm. Larger net chords or multiple chords are possible; however, the chord(s) design should be constrained to beneath threshold force to dynamic break loads typical of RPG impact and engagements. 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 190 mm.
The preferred spacing or standoff from the net to the vehicle is between 4 and 24 inches, (e.g., 6-12 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 struts and the like 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.
The result, in various embodiments, is a lighter weight system which is easy to deploy and then deactivate and stow. In some embodiments, coverage of the hard points is also improved.
In this manner, hour glassing of the opposing sides of net shield 100 is prevented.
In
Although specific features of the invention are shown in some drawings and not in others, 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 is a continuation of U.S. patent application Ser. No. 13/200,296 filed Sep. 22, 2011 which hereby claims the benefit of and priority thereto under 35 U.S.C. §§119, 120, 363, 365. and 37 C.F.R. §1.55 and §1.78, which is a continuation-in-part of U.S. patent application Ser. No. 12/807,532 filed Sep. 8, 2010, which is a continuation-in-part of and claims benefit of and priority to U.S. patent application Ser. No. 12/386,114 filed Apr. 14, 2009, which claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/124,428 filed Apr. 16, 2008.
This invention was made with U.S. Government support under Contract No. HR0011-09-C-0017 awarded by DARPA. The Government has certain rights in the invention.
Number | Date | Country | |
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61124428 | Apr 2008 | US |
Number | Date | Country | |
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Parent | 13200296 | Sep 2011 | US |
Child | 13873839 | US |
Number | Date | Country | |
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Parent | 12807532 | Sep 2010 | US |
Child | 13200296 | US | |
Parent | 12386114 | Apr 2009 | US |
Child | 12807532 | US |