WO2004109215A1

WO2004109215A1 - Ballistic demining protective armor

Info

Publication number: WO2004109215A1
Application number: PCT/CA2004/000843
Authority: WO
Inventors: Roger J. Soar; Ian Swan
Original assignee: Pacific Safety Products Inc.
Priority date: 2003-06-06
Filing date: 2004-06-07
Publication date: 2004-12-16

Abstract

A demining protective armor (22) consists of means for preventing through-penetration of abrasive soil particulate ejecta, excluding means for preventing through-penetration of ballistic projectiles. In one embodiment the means for preventing through-penetration of soil ejecta includes a flexible garment (10) disposed outwardly so as to be between a land mine blast and the body of a user when the garment (10) is worn by the user. An outer cover (18) of the garment is disposed as a strike-face on a blast-side of the garment when worn by the user. Two side-by-side plies of ballistic nylon (12, 14) woven fabric are mounted adjacent the outer cover. One ply of non-woven ballistic felt (16) is mounted adjacent the two side-by-side plies of ballistic nylon (12, 14), opposite from the outer cover. An adjacent inner cover (20) is mounted on a body-side of the garment (10).

Description

BALLISTIC DEMINING PROTECTIVE ARMOR

Field of the Invention

This invention relates to the field of ballistic body armor and in particular to body armor worn as a garment by mine clearing personnel and to the lightweight protective panels from which the garments are made.

Background of the Invention

In some humanitarian demining situations, the primary threat to the deminer is soil ejecta in the form of soil particles and associated micro-particles. It is possible, however, to armor the deminer against this debris with relatively lightweight materials that are remarkably thin and inexpensive. The potential comfort and practicality of such 'soft' armor may lead to a greater acceptance by the humanitarian demining community, and could result in decreased levels of injury in that application. What is meant herein by humanitarian demining community would or could include non-governmental organizations having volunteers and training staff to provide trainees with training and equipment. These trainees are often drawn from local civilian population. The mines are typically found in areas where the civilian population live and work.

In our provisional patent application serial number 60/476, 188, incorporated herein by reference, we disclose the results of tests done using body armor to protect the skin of test mannequins used in testing the effects of exploding land mines on humans. In those tests, it became apparent that if a different approach than taken in the prior art was used in demining body armor, then lightweight pliable and relatively inexpensive to manufacture demining body armor employing for example merely a minimum of three layers, namely two layers of 1050 denier ballistic nylon having a 1 oz./sq.m polyurethane coating, and one layer of non-woven aramid needle-punched felt, for example of Kevlar™ or Twaron™, could be employed to protect against abrasion due to soil ejecta. In our provisional disclosure, we postulate that the successful body armor evidenced in the testing may be used to protect humans.

In the prior art, applicants are aware of conventional so-called explosive ordinance disposal (EOD) suits also referred to as personal protective equipment (PPE) and like heavy body armor employed by military, police, and the like by their EOD personnel. Such equipment is manufactured commercially by, for example Med-Eng Systems Inc. of Ottawa, Canada. Prior art of which applicant is aware includes that belonging to Med-Eng Systems Inc., such as the following US patents:

Such heavy body armor is designed to protect against ballistic projectile and fragmentation projectile penetration resulting from an exploding anti-personnel (AP) fragmentation mine. The armor is consequently heavily armored. In applicants' experience, such heavy body armor is expensive to manufacture, cumbersome and poorly ventilated or cooled.

Consequently, it is in the applicants' view impractical, unreasonable to expect, and unlikely that demining personnel clearing land mines all day long in hot climates would be inclined to wear such conventional demining PPE due to the extreme discomfort they would have to endure, even if it could be provided or afforded. Exemplary EOD and ballistic body armor prior art of which applicants' are aware includes the following patents: United States Patent No. 6,022,601 which issued to Pfister et al. on February 8, 2000; United States Patent No. 5,724,670 which issued to Price on March 10, 1998; United States Patent No. 5,660,913 which issued to Coppage, Jr. on August 26, 1997; United States Patent No. 5,180,880 which issued to Bachner, Jr. on December 5, 2000; United States Patent No. United States Patent No. 5,179,244 which issued to Zufle on January 12, 1993; and United States Patent No. 4,608,717 which issued to Dunbavand on September 2, 1986. Although only very recently published, applicant is also aware of the Final Report of the NATO Research and Technology Organization Human Factors and Medicine Panel, Task Group TG-024, entitled Test Methodologies for Personal Protective Equipment Against Anti-Personnel Mine Blast, published March 2004, which describes current mine protection equipment (at Annex B).

That report describes at page 1-2 the difference between fragmentation and blast mines. In particular, the repost states that "Fragmentation mines... are area weapons that explosively disperse high velocity fragments that injure or kill personnel up to several tens of meters away. If initiated very close to the intended victim, the victim is also injured by blast, but if this is the case, the victim also has a very high probability of being killed by the fragments. Fragmentation mines can be activated through a variety of stimuli such as downward pressure or the pull from a trip wire. There also exist sophisticated fuse systems that detect ground vibrations, noise or infrared signatures, but these fuse types are not widely available and are seldom used in practice. With trip wires, it is difficult to predict the direction of a fragmentation mine attack. Thus, soldiers require all-round protection to defend against such a weapon.

The situation for AP blast mines is quite different, These devices come in a wide range of shapes, materials and colors. They often contain only a minimal amount of metal, which makes them difficult to detect with current mine detectors. Furthermore, they are designed for concealment in the ground, waiting for activation by the victim. They injure primarily by the direct effect of blast on human tissues. However, the mine case and the internal trigger mechanism break up and can become fragments that also injure the victim. The blast also propels soil, small pebbles, and other environmental debris that cause further fragmentation injuries and contaminate wounds.

Accidents involving buried blast mines ... occur either when the victim steps on the mine or while the victim is trying to locate and remove a mine. Each type of accident yields a well-defined pattern of injury. When the victim steps on a blast mine, the body is usually in the standing position, which places the lower extremities closest to the blast while the sensitive organs of the upper body are further away. The near contact of the lower extremity with the blast results in traumatic amputation of the leg and sever contamination of adjacent soft tissues. When the accident occurs during mine clearance, the soldier is usually lying prone or in a kneeling position and, with the exception of the hands, most body parts are not in direct contact with the blast. However, the reduced distance from the blast greatly increases the probability of injury to the head and upper body organs."

The report further states at page 2-3 that "thermal injury is common with any close range explosion, but it is often overwhelmed and hidden by other injury mechanisms. For a mine, thermal injury is usually restricted to the very near region to the blast and its severity depends on the time of exposure.... In the worst case, the duration of the after burn is of the order of 10-25ms, but the temperature can be of the order of 1000°C, which is sufficient to cause thermal injury. Blast injury is easier to notice. From a macroscopic point of view, the very high pressure near the explosion source overwhelms the strength of human tissues, causing their disintegration. Further away, the blast can cause more macroscopic injuries including damage to the ears, respiratory tract, and to the gastro-intestinal tract. Blast lung...can occur if the explosive mass is large enough or if the distance is small enough."

The report also states at page 2-4 that "the expansion of the detonation products is believed to be a dominant injury mechanism to human tissue. Several studies...quantified the mine explosion process in physical terms such as pressure and velocity. It takes only 5 μs for the detonation wave to transform the solid explosive into high-pressure gas. From that point onward, the soil confines the expansion of the detonation products. The hot gas pushes on its surroundings, deforming the soil directly above the mine into a hemispherical cap.... Hot gas then breaks through the soil surface at several points and jets out at supersonic speed, pushing the air ahead and creating an air shock. The push of the gas also creates soil ejecta, a stream of soil particles that flow along a thin conical zone surrounding the gas core." (reference numerals in the above quotations have been removed)

Summary of the Invention

The outcome of test trials revealed that ballistic threats commonly considered for the design of demining suits may be not applicable for humanitarian demining applications. The threat resulting from demining anti-personnel mines where a deminer will stand or crouch in proximity to the mine, is associated predominantly with soil ejecta characterized by high-speed soil debris and micro-particles that erode protection through abrasion. It was determined that while thin layers of aramids were ineffective at preventing particle penetration, other material combinations as disclosed herein turned out to be quite successful.

The present invention represents, in applicants' view, a fundamental shift in the approach taken to protecting humanitarian mine-clearing personnel, herein alternatively referred to as deminers. Rather than liaving as a primary objective the protecting against fragmentation penetration, as well documented in the prior art, applicants have recognized that a primary threat faced by deminers, and that which statistically takes the majority of the lives of deminers, is the result of massive skin abrasion due to the abrasive effects of soil ejecta when a deminer is in close proximity to an exploding anti-personnel blast mine. Statistically, the primary cause of death of such deminers is not from fragmentation wounds, but rather from massive skin loss and infection. Consequently, if demining body armor was for the most part to serve the purpose of protecting against massive skin abrasion due to soil ej ecta in the form of lightweight inexpensive body armor, which in applicants' view would consequently increase the likelihood that such body armor would be worn by a much larger percentage of deminers, then such body armor would likely save many lives. It is understood that such body armor is not designed to prevent fragmentation penetration to the same level of protection demining PPE suits.

Thus, the present invention in one preferred embodiment comprises no less than two layers of ballistic nylon, such as 1050 denier ballistic nylon, as the strike face adjacent a single layer disposed towards the body of non- woven aramid felt such as manufactured and available commercially from TEIJIN TWARON BV of 6800 TC Axnhem, The Netherlands (Twaron™), and DuPont, of Richmond, NA., USA (Kevlar™) aramid felt. The felt layer is located between the nylon layers and the body of the deminer. The felt may be described as needle-punched non- woven aramid fiber felt. As an example, Twaron #9 felt has a weight of 300 grams/sq.m. The minimum of three layers or plies forming the panel structure may advantageously be encased between and within waterproof membranes or layers. Collectively this structure is referred to herein as "demining armor", for example forming a waterproof pouch, apron or the like, or other garment. In the preferred embodiment, a demining garment manufactured according to the preferred embodiment, may take the form of an apron of demining armor to be worn by a deminer so as to cover the front of the torso and at least the groin and upper legs, keeping in mind that many deminers, in applicants understanding, will crouch or squat when demining or otherwise assume the position used during, for example, their farming activities if they are lay farmers clearing their fields of AP mines. Additionally, sleeves of demining armor may be provided to protect at least the arms and shoulders. A collar of demining armor protects the neck above the apron. It is expected that the deminer would wear a conventional protective face shield which would extend downwardly so as to overlap the collar, in addition to conventional protective gloves, boots, etc.

The present invention may be characterized as ballistic demining protective armor comprising in a preferred embodiment a blast panel, and a garment constructed using the blast panel so as to be disposed outwardly of the body of a user when worn, having a minimum of two and no more than five side-by-side plies of ballistic nylon woven fabric (the greater the denier no., the less plies required for a particular level of protection) adjacent the outer cover, and one or more ply of non- woven needle-punched aramid felt adjacent the body-side of the panel or garment.

More broadly stated, and in keeping with our new approach to humanitarian demining protection, the present invention may also be characterized as demining protective armor which consists of means for preventing through-penetration of soil ejecta, that is, preventing penetration of soil ej ecta completely through the armor, and has a limited capability for preventing, that is which reduces, through-penetration of ballistic projectiles, (typically 17 grain or greater) wherein the means for preventing through-penetration of soil ejecta may include the preferred embodiment summarized above, but may also include other embodiments where the number of layers are increased, or other layers of material interleaved in keeping with the limitation that protection against through-penetration is still only provided primarily against soil ejecta.

In summary then the ballistic demining protective armor of the present invention consists of: (a) A panel comprising means for preventing through-penetration of abrasive soil particulate ejecta comprising high velocity micro-particles of less than substantially 2.5mm diameter and having less than approximately or substantially 1,000 m/s velocity, and, (b) for reducing through-penetration of ballistic projectiles characterized as 17 grain FSP (fragment simulating projectile) at substantially greater than 325 m/s. In one embodiment the panel is formed as a flexible garment disposed outwardly so as to be between a land mine blast and the body of a user when the garment is worn by the user. An outer cover of the garment is disposed as a strike-face on a blast-side of the garment when worn by the user. At least two side-by-side plies of ballistic nylon (approximately 1 ,000 denier) woven fabric are mounted adjacent the outer cover. No more than 5 plies should be required. The plies of ballistic nylon may include coating, such as a polyurethane coating, to form a flexible matrix holding fibers of the nylon substantially locked in place relative to one another so as to inhibit fiber displacement. One ply of non- woven aramid felt or a substantive equivalent (for example a plurality of lighter weight layers) is mounted adjacent the two side-by-side plies of ballistic nylon, opposite from the outer cover. An adjacent inner cover is mounted on a body-side of the garment. To reiterate, the demining protectivb armor according to one aspect of the present invention only consists of means for preventing through-penetration due to blast of abrasive soil particulate ejecta wherein the ejecta are high velocity micro-particles of less than substantially 2.5mm diameter and having less than approximately or substantially 1,000 meters per second velocity and to thereby only inhibit without necessarily preventing, through-penetration of ballistic projectiles of 17 grain FSP at substantially greater than 325 meters per second velocity. The means for preventing through-penetration of soil ejecta includes a flexible panel for use in a garment to be worn disposed outwardly so as to be between a land mine blast and the body of a user when the garment is worn by the user. An outer cover of the garment is disposed as a strike- face on a blast-side of the garment when worn by the user. Between two and five side-by-side plies of ballistic nylon woven fabric are disposed adjacent the outer cover. Non-woven aramid felt is disposed adjacent the side-by-side plies of ballistic nylon, opposite from the outer cover, and adjacent an inner cover on a body-side of the garment.

Brief Description of the Drawings

Figure 1 is a deminer wearing one embodiment of a demining garment incorporating the demining armor according to the present invention.

Figure 2 is a partially cut away exploded view of a portion of the garment of Figure

1 illustrating the combination of plies forming the ballistic material from which the garment of Figure 1 is constructed.

Detailed Description of Preferred Embodiments

Land mine blasts generate extensive erosion and pitting of materials in proximity to the blast. The damaged field is not uniform. In testing, areas of focused damage move from place to place from one test to the next. This is intrinsic to the nature of a land mine blast and represents the real threat that must be protected against. Applicants attribute concentrated areas of penetration of test materials to jets of material being expelled from the blast zone. In the testing documented in our provisional application, the particle tracks left within the test material varied in size from 250 microns (0.010 inches) in diameter to as much as 3 millimeters (one eighth inch). As also documented in our provisional patent application from which this patent application claims priority, a combination of two-ply 1050 denier ballistic nylon backed with a single ply of Twaron ™ felt exhibited no penetrations even after being exposed to two mine blasts. The front face of the test sample displayed large areas of fine dust deposition and a limited number of larger impact points. Entrainment of fine dust through the impact points also took place, as evidenced by deposition on the front face of the second layer of the ballistic nylon. However, the second layer was sufficient at stopping the larger particles, which only left an impression in the Twaron ™ felt. The area density of this combination is 1356 grams per square meter. During N-50 evaluation of the two-ply 1050 denier ballistic nylon backed with one-ply Twaron ™ felt combination, applicants' observed that the back face signature, that being the indentation in ΝIJ calibrated clay, of the non-penetrating particles range between 12.7 millimeters (0.5 inches) and 19 millimeters (0.75 inches) for both a one-grain sphere and a seventeen-grain FSP. The combination of materials thus proves successful in stopping micro-particles of dust as well as larger projectiles. The following table sets out the particle sieve sizes for typical test media against which the panel of the present invention was tested and the corresponding percentage of particles passing through each sieve size. Distribution of Test Particles

Thus as may be seen in Figures 1 and 2, wliich illustrate one embodiment employing the present invention, demining personnel may wear a ballistic demining protective garment 10, such as the long sleeved apron illustrated, wholly made from sheets of demining armor employing two adjacent plies of 1050 denier ballistic nylon 12 and 14, and one ply of Twaron ™ felt 16 immediately adjacent the two plies of ballistic nylon 12 and 14. The plies of ballistic nylon and the ply of Twaron ™ felt are encased between flexible waterproof sheets 18 and 20. Within garment 10, the ply of Twaron ™ felt is sandwiched between, on one side, the two plies of ballistic nylon, and, on the other side, one of the waterproof sheets and the body of the deminer. In garment 10, the sheets of the demining armor combination 22 are, in the illustrated embodiment, and without intending to be limiting, fashioned into a high collar 24, which advantageously extends far enough up the neck of the deminer so as to overlap behind a face shield 26. Sleeves 28, and a torso and leg covering portion 30 are also provided, again constructed of demining armor combination 22.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. Demining protective armor only consisting of means for preventing through-penetration due to blast of abrasive soil particulate ejecta wherein said ejecta are high velocity micro- particles of less than substantially 2.5mm diameter and having less than substantially 1 ,000 meters per second velocity and to thereby only inhibit without necessarily preventing, through-penetration of ballistic proj ectiles of 17 grain F SP at substantially greater than 325 meters per second velocity.

2. The armor of claim 1 wherein said means for preventing through-penetration of soil ejecta includes a flexible panel for use in a garment to be worn disposed outwardly so as to be between a land mine blast and the body of a user when said garment is worn by the user, an outer cover of said garment disposed as a strike-face on a blast-side of said garment when worn by the user, between two and five side-by-side plies of ballistic nylon woven fabric adjacent said outer cover, non- woven aramid felt adjacent said side-by-side plies of ballistic nylon, opposite from said outer cover, and adjacent an inner cover on a body-side of the garment.

3. The armor of claim 2 wherein said plies of ballistic nylon are two plies of ballistic nylon of 1050 denier ballistic nylon.

4. The armor of claim 3 wherein said plies of ballistic nylon include a coating to form a flexible matrix holding fibers of said nylon substantially locked in place relative to one another so as to inhibit displacement.

The armor of claim 2 wherein said aramid felt is needle-punched aramid fiber felt having a collective weight of 300 grams/square meter.

6. The armor of claim 2 wherein said panel contains only two side-by-side plies of said plies of ballistic nylon.

7. The armor of claim 2 wherein said panel contains only one ply of aramid felt.

8. The armor of claim 2 wherein said panel contains only two side-by-side plies of said plies of ballistic nylon and only one ply of said aramid felt.

9. The armor of claim 8 wherein said two side-by-side plies of ballistic nylon are immediately adjacent and contacting said ply of ballistic felt.

10. The armor of claim 9 wherein said two plies of ballistic nylon and said ply of ballistic felt are the only plies of ballistic material within said garment.

11. The armor of claim 10 wherein said two plies of ballistic nylon are 1050 denier ballistic nylon and said ballistic felt is non- woven aramid fiber felt.

12. The armor of claim 2 wherein said inner and outer covers are waterproof.