US 20070234458 A1
A composite ballistic material has one or more layers of flexible ballistic fabric and a plurality of scales disposed in an overlapping configuration. Scale configurations may vary depending on an intended use. However, the scales may have a substantially uniform thickness and may also have a mounting portion and an overlapping portion. The mounting portions may be aligned in a single layer. The overlapping portions may extend wider than the mounting portions. The overlapping portions may also be substantially non-planar. The overlapping portions may be arranged so that the overlapping portion of individual scales lies under or over the overlapping portion of adjacent scales. Scales may be initially joined with a binder in rows and subsequently joined to a flexible fabric to create the overlap in a direction substantially perpendicular to the rows.
1. A composite ballistic material comprising:
one or more layers of flexible ballistic fabric; and
a plurality of scales arranged in an overlapping configuration, the individual scales having a mounting portion and an overlapping portion, the mounting portions of the plurality of scales being disposed substantially in a non-overlapping layer, the overlapping portions of the scales having a first surface and a second surface spaced apart by a substantially constant thickness, an amount of the overlapping portion of a single scale that lies over or under other scales being between about 15 to 35 percent of a first overall width of the first surface in a first direction.
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9. A composite ballistic material comprising:
one or more layers of flexible ballistic fabric; and
a plurality of scales having a substantially uniform thickness and further having a mounting portion and an overlapping portion, the mounting portions of the plurality of scales being disposed substantially in a non-overlapping layer, the overlapping portions of the plurality of scales being substantially non-planar and being arranged in an overlapping configuration so that the overlapping portion of individual scales lies under or over the overlapping portion of adjacent scales.
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16. A method of constructing a composite ballistic material, the method comprising:
joining a row of scales having a substantially uniform thickness along a first direction to a plurality of flexible binders, each of the plurality of scales having a mounting portion and an overlapping portion, the mounting portions being disposed on the flexible binder in substantially in a non-overlapping layer, the overlapping portions of the scales being substantially non-planar and arranged in an overlapping configuration so that the overlapping portion of individual scales lies under or over the overlapping portion of adjacent scales; and
joining the plurality of flexible binders to a flexible fabric so that the overlapping portion of scales disposed on a first binder overlap the overlapping portion of scales disposed on a second binder.
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Personal body armor is worn by individuals to protect themselves from high velocity projectiles such as bullets and shrapnel. Clearly, the ultimate objective for armor and the materials from which the armor is comprised is to limit bodily harm that can be caused by such ballistic threats. An unfortunate reality of military arenas is that threatening conditions are pervasive. For that matter, threat scenarios are even omnipresent in civilian contexts. As a consequence, personal body armor may be worn for extended periods of time. Therefore, a subsidiary objective for personal body armor is that the armor be as light and comfortable as possible.
Another consideration pertains to flexibility of the armor. Certain conventional solutions use substantial metal and ceramic plates to provide ballistic protection. The hardness of these materials offers adequate protection but their hardness also contributes to a large and heavy solution. Even where smaller plates are used, the rigidity of the plates hinders overall flexibility. Other conventional solutions use a plurality of layers of high performance fiber material such as Kevlar® from DuPont and K-Flex®/T-Flex™. Unfortunately, protection from high-speed projectiles requires a commensurate increase in the number of layers of the ballistic fabric needed to provide protection. Additional layers, flexible though they may be, increase weight and decrease flexibility.
To increase flexibility, other conventional solutions use tiled configurations that permit relative motion between tiles. Some of these solutions have gaps between tiles that are vulnerable to ballistic penetration. Other solutions use an overlapping tile configuration but do not provide sufficient overlap to account for body flexure and inter-tile exposure that may occur if the wearer is in a reaching or bent position. Vulnerability between tiles may also be a legitimate problem where protection in close range or hand-to-hand combat is a concern.
The National Institute of Justice (NIJ) has developed a set of performance requirements in NIJ Standard 0101.04 establishing a minimum level of ballistic protection against different types of bullets. This standard recognizes the contradicting objectives discussed above. “Body armor selection is to some extent a tradeoff between ballistic protection and wearability. The weight and bulk of body armor are inversely proportional to the level of ballistic protection it provides; therefore, comfort decreases as the protection level increases.” Ballistic Resistance of Personal Body Armor, Revision A, NIJ Standard 0101.04, June 2001 at page 44. This statement reflects a necessary and commonly recognized compromise associated with conventional body armor. Accordingly, existing solutions may not provide an optimal solution that balances protection, comfort, and flexibility.
Embodiments of the present invention are directed to a composite ballistic material that uses one or more layers of flexible ballistic fabric in conjunction with a plurality of scales disposed in an overlapping configuration. Scale configurations may vary depending on an intended use. In general, the scales may have a substantially uniform thickness. Furthermore, the scales may also have a mounting portion and an overlapping portion. The mounting portions may be aligned in a single layer. For example, the scales may be initially joined to a binder in rows and subsequently joined to a flexible fabric to create overlap in a direction substantially perpendicular to the rows.
The overlapping portions of the scales may have different configurations. For example, in some embodiments, the overlapping portions may extend wider than the mounting portions. In certain embodiments, the overlapping portions may also be substantially non-planar. The overlapping portions may be arranged so that the overlapping portion of individual scales lies under or over the overlapping portion of adjacent scales. Some scales have curved configurations that may be particularly suitable to curved portions of a body armor device. Some scales may have overlapping portions disposed on one side of a mounting portion while others have overlapping portions disposed on opposing sides of a mounting portion.
The various embodiments disclosed herein are directed to a material composition for use in body armor. Different configurations implement scales that are joined to a flexible fabric to create a composite structure. The composite structure may be used in protective body armor such as that generally shown in
The illustrated vest 10 includes a neck aperture 12 and a pair of arm apertures 14 and generally provides coverage for a human torso. The composite structure 100 may cover some (as shown) or the entire vest 10. In one embodiment, the composite structure 100 comprises a plurality of individual scales 16 that are disposed in an overlapping arrangement. That is, a majority of scales 16 have other scales 16 that cover some portion of those scales 16 while simultaneously covering other scales 16. Further, overlapping exists in both the vertical and horizontal directions as shown.
In one embodiment, the scales 16 are constructed from a thermoplastic polymer, though other materials may be implemented. Suitable examples may include, polyethylene, polypropylene, PMMA. In one embodiment, the scales 16 are constructed of 0.125″ or 0.063″ thick polycarbonate. Additional details of the scales 16 and other scale configurations are provided below.
As indicated, the scales 16 overlap in multiple directions and preferably by an amount that prevents inter-scale separation that may expose vulnerable gaps in the composite structure 100.
In one embodiment, the layer of overlapping scales 16 is joined to an adjacent layer 18 a of ballistic fabric. This first layer 1 8 a may then be joined, at least loosely, to a remaining plurality of layers 18 b. The quantity of layers 18 b used for a particular application may vary depending on the performance requirements. In general, the composite structure 100 should be sufficient to radially redirect the kinetic pulse that is caused by projectile impact. In an exemplary embodiment, a layer of overlapping scales 16 and less than 10 layers of ballistic fabric were sufficient to limit back face signature to between 0.8 and 0.9 inches. An acceptable limit of 1.73 inches is established by NIJ Standard 0101.04 for different ammunition, including Full Metal Jacketed 9 mm and Jacketed Soft Point 0.44 Magnum bullets. By comparison, body armor such as vest 10 that only incorporates layers 18 b of ballistic fabric may require as much as about two times the number of layers to simply meet the NIJ standard. Many more layers may be required to achieve the same performance as the composite structure 100.
One advantage provided by the composite structure 100 is that the scales 16 are lighter than metal or ceramic equivalents. However, this does not preclude the use of metal or ceramic scales 16 as these other materials may provide different performance characteristics suitable for a particular application. In any event, the scales 16 are joined to a layer 18 a of ballistic fabric in such a manner that the composite structure 100 may flex while it is worn. This flexure is illustrated in
The overlapping portion 22 is generally circular and may be dome shaped 22 a as illustrated in the cross section view provided in
The overlapping portion 22 of the exemplary scales 16 is substantially circular. Further, the scales 16 are joined to an underlying layer 18 a of ballistic fabric at the mounting portion 20. As a result, the free end of the scale (bottom end in the orientation shown in
As indicated, the mounting portions 20 of a given scale 16 are narrower than the overlapping portions 22. This configuration allows the scales 16 to be positioned so that the mounting portions 20 abut one another at a junction 28. Absolute contact between adjacent mounting portions 20 is not expressly required but may be desirable. At the least, the mounting portions 20 of adjacent scales 16 should be placed in close proximity to one another to increase the amount of overlap L1. Dimension L1 describes the amount of horizontal overlap between adjacent scales 16. Notably, this dimension L1 is at least partly determined by the extent to which the width or diameter of overlapping portion 22 exceeds the mounting portion 20 (see also
The amount by which a single scale 16 lies under or over an adjacent scale 16 is shown qualitatively as the cross hatched area 26 in
One advantage to this configuration is that individual rows 36 of scales 16 may be pre-fabricated in extended stock lengths. Then, a desired length may be cut from the stock lengths and joined to a layer 18 a of ballistic fabric in a vertically overlapping configuration at the desired pitch P. Further, the binding 30 may be made from a fabric that permits the row 36 of scales 16 to be stitched to a layer 18 a of ballistic fabric in an expeditious manner. Furthermore, the binding 30 may itself be flexible, thus contributing to the overall flexibility of the composite structure 100.
The scales 16 described thus far have a profile generally illustrated in
The curved overlapping portion 122 is more clearly shown in
Another type of scale 216 is illustrated in
The length D6 of the individual overlapping portions 222 a, 222 b, 222 c may vary. Symmetry may be preserved by using a length D6 that is approximately one third the overall length of the scale 216. Further, the corrugated geometry may be obtained by orienting the overlapping portions 222 a, 222 b, 222 c at an angle α with respect to one another. A range of angles may be used with smaller angles resulting in a lower profile. For example, an angle α of about 15-25 degrees may be suitable. In one embodiment, an angle α of about 19 degrees is used.
Alternative scales 217, 218 similar to scale 216 are presented in
The elongated scales 216, 217, 218 may provide enhanced protection due to the additional overlap in the long direction (direction of length D5). These scales 216, 217, 218 may be particularly suitable for the chest region of a vest 110, where less flexibility and greater protection may be required. In contrast, the smaller scales 16, or the curved scales 116,118 may be suitable for other regions of a vest 110. In combination, the use of these scales 16, 116, 118, 216, 217, 218 in protective armor such as vests 10, 110 may provide an effective compromise between protection, weight, and flexibility.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. For example, the embodiments described above have contemplated attaching the scales to a layer of ballistic fabric. It may be desirable to attach the scales to a thin non-ballistic fabric that is subsequently attached to layers of ballistic fabric. This and other manufacturing considerations may call for other manufacturing techniques. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.