Method and apparatus for defeating high-velocity projectiles

IS 2 373 145 T3

DESCRIPTION

Procedure and apparatus for neutralizing high velocity projectiles

Background of the Invention (1) Field of the Invention

The invention relates to protective clothing. More specifically, the invention relates to flexible body armor that is designed to neutralize high velocity projectiles.

(2. Background

Advances in body armor often refer to the development of improved materials from which armor is formed. In recent years, ballistic resistant materials that are formed from fibers with high tensile strength, such as aramid fibers or polyethylene fibers, have become in common use in the industry. Unfortunately, soft body armor, even with these advanced materials, has proven insufficient even to nullify armor piercing pistol ammunition, sharp thrust tools, and circular penetrators, all of which are now in common use.

To address this problem, various carbide shielding systems have been developed. Such a system employs a number of titanium discs one inch in diameter (2.54 cm) and 0.813 mm to 1.27 mm (0.032 to 0.050 inches) thick that are arranged in overlapping rows in such a way that inside a row, a disk overlaps its predecessor in the row and its successor in the row overlaps it. Subsequent rows overlap their predecessor and their successor overlaps them. The coin array is then attached to a substrate such as an adhesive impregnated aramid fabric. A second layer of aramid impregnated with adhesive can be used to wrap the "plate" that is formed by the coins. This wrapped plate can be attached to conventional flexible body armor over the vital organs. This provides good flexibility and is thin enough to be hidden.

Similarly, United States patents n.^you 3,563,836 and 5,196,252 disclose a projectile resistant armor comprising a plurality of unmilled plates that are attached to the surface of a flexible substrate. The plates are attached adjacently to the flexible substrate in a non-overlapping manner in any one layer, the plate-layered substrates can then be layered one on top of the other to create an overlapping plate configuration. The additional substrate layers are used to coat the plate layers and create projectile resistant armor.

Although this overlapping of coins and plates has been shown to effectively disperse force to neutralize most existing armor piercing gun shells, sharp thrust tools, and circular penetrators, rifle shells unfortunately continue to tear apart. through this shielding structure, as well as the underlying flexible body armor like a hot knife cuts through butter. Therefore, for protection against rifle projectiles, users have been required to use large rigid plates to protect vital organs. These large plates are heavy and not flexible at all, and generally not very comfortable to use. Additionally, these are almost impossible to use in such a way that they are hidden. Efforts to employ the coin design with thicker discs have been unable to produce a commercially viable product for neutralizing rifle shells. Thicker discs result in less flexibility and do not lay out well. The result is a thicker shielding structure, which is no longer flexible, and heavier than the solid plates previously discussed. User comfort is also a special concern in body armor production. Consequently, these limitations make such a structure impractical as a commercial product.

In view of the above, it would be desirable to have a flexible armor system that would neutralize high velocity projectiles, such as rifle projectiles.

Brief summary of the invention

An apparatus for neutralizing high velocity projectiles is disclosed in claim 1 and a manufacturing method thereof is disclosed in claim 15. Preferably, a plurality of disks of equal size and having a thickness greater than 2, 54mm (0.100 ”) are milled in a plurality of locations. Each milled location having a radius of curvature approximately equal to the radius of curvature of the disc. The discs are then arranged in an interwoven pattern row by row such that each disc in a row lies in a substantially straight line with the other discs in the row and overlaps a milled location of a disc in a row by above its row and has its milled place overlapped by a row disk below its row. The embedded pattern is then adhered to a flexible high tensile substrate and overlapped by a second high tensile strength layer such that the embedded pattern is wrapped between the substrate and the second layer. The wrap is then attached to a flexible body armor support.

In an alternate embodiment, a method and apparatus for neutralizing high-pressure projectiles are disclosed.

ES 2 373 145 T3 speed. A plurality of disks of equal size are provided comprising fiber-induced ceramic composites. The discs are arranged in an interwoven pattern row by row such that each disc in a row lies in a substantially straight line with the other discs in the row and overlaps a segment of a disc in an adjacent row. The embedded pattern is then adhered to a flexible high tensile substrate and overlapped by a second high tensile strength layer such that the embedded pattern is wrapped between the substrate and the second layer. The wrap is then attached to a flexible body armor support.

Brief description of the drawings

Figure 1 is a schematic cutaway diagram of a body armor assembly of one embodiment of the present invention.

Figure 2 is a perspective diagram of the arrangement of the discs in one embodiment of the invention.

Figure 3 is a diagram of an embedded pattern adhering to a substrate.

Figure 4 is an envelope diagram of the interwoven pattern between a substrate and an additional layer.

Figure 5 is a perspective view of a disk of an alternative embodiment of the invention.

Figure 6 is a sectional view of the disk of the embodiment of Figure 5.

Figure 7 is a perspective view of a disk of a second alternative embodiment of the invention.

Figure 8 is a cross-sectional view of the disk of the embodiment of Figure 7.

Figure 9 is a front view of one embodiment of body armor.

Figure 10 is a sectional view of one embodiment of the body armor.

Figure 11 is a side sectional cross-sectional view of one embodiment of the body armor.

Figure 12 is a perspective view of one embodiment of a disk.

Figure 13 is a perspective view of the embodiment of a disk of Figure 4 with a coating of

Eglass and epoxy modified resin.

Figure 14 is a sectional view of the embodiment of a disk of Figure 5 illustrating the liners.

Figure 15 is a perspective view of one embodiment of a disk.

Figure 16 is a sectional view of one embodiment of a disk.

Detailed description of the invention

Figure 1 is a schematic cutaway diagram of a body armor assembly of one embodiment of the present invention. Body armor 10 covers a wearer's torso and is designed to protect vital areas from high velocity projectiles. Through the appropriately shaped arrangement of the discs in an interwoven pattern, the overall body armor 10 remains flexible and also provides good protection against high velocity projectiles. Unlike the rigid 10 x 12 plates of the prior art, the embedded pattern can flex around the contours of the body and is therefore considerably more comfortable and can also be hidden more easily. The interwoven pattern 12 is typically sandwiched between two fabric layers 14 which are made of fibers with a high tensile strength, such as aramid fibers or polyethylene fibers. The fabric 14 is to be tear and cut resistant and is preferably ballistic grade material that is designed to reduce fragmentation. This fabric 14 may be impregnated with adhesive, therefore, the adhesive on the fabric adheres to the discs that make up the embedded pattern 12 and retains its relative position. One or more additional layers of fabric 14 can be added to the sandwich. This will be discussed further later.

Underlying the interwoven pattern 12 which is sandwiched between two or more layers of the tear and cut resistant fabric layers 14 is a conventional flexible body armor 16. A high velocity projectile is considered neutralized even if it penetrates the interlocking pattern armor and all layers of tissue if it does not penetrate the underlying flexible body armor or results in a rear end deformation greater than 44mm (1.73 ”). ), as defined posterior deformation by the National Institute of Justice (NIJ). Attachment straps, such as strap 18, attach a front panel of body armor 10 to a rear panel of body armor 10 in a conventional manner. The coupling strip 18 can be any conventional strip system common in the industry.

Figure 2 is a perspective diagram of the arrangement of the discs in one embodiment of the invention. In this case, the discs are arranged from left to right. Each subsequent row is also arranged from left to right. Switching from left to right, then right to left, has been found to create a weakness in the resulting pattern that often results in failure. Figure 2 shows only a two-row portion of the final interwoven pattern. The discs within each row form a substantially straight line. Because the discs overlap, each disc has a slight slope relative to a line normal to the layout surface. Additionally, each disc is rotated slightly such that a line through the center of a row in conjunction with an axis that cuts the milling arc of the center milling location in two equal parts is not a right angle. In one embodiment, this angle is approximately 60 °. A typical disc 52 is shown raised above its final placement in pattern 50. Disc 52 is typically a high hardness material, having a hardness greater than 450 Brinell. There are many suitable materials, including high carbon steel, stainless steel, steel alloys, and various

ES 2 373 145 T3 titanium alloys. A preferred material is marketed under the trademark Mars 300 ™, and is available from Creusot-Loure Industries, a division of Creusot Marrel of France. Mars 300 ™ typically has a hardness of 630 to 650 Brinell. Other suitable material is sold under the trademark BP 633 ™ from Astralloy of Birmingham, Alabama. More suitable materials are sold in sheets. Mars 300 ™ is purchased in sheets that are approximately 0.4267mm (0.168 ”) thick. The individual discs have to be cut from the sheets. This can be accomplished by plasma cutting, laser cutting, or waterjet cutting, depending on the material used. "Cutting" as used herein (when unmodified) refers generically to any technique by which a disc is produced.

In one embodiment, the disc 52 is laser cut using conventional laser technology to ensure a uniform diameter and smooth edge such as between multiple discs. Waterjet cutting can be used but is not believed to be as good as laser cutting. Plasma cutting would also be possible but would then require additional deburring and smoothing steps to obtain the same edge smoothness. After cutting, each disc 52 is milled, disc 52 milled in three locations - a left milled location 54, a center milled location 58, and a right milled location 56. This milling can be done in any order.

In one embodiment, each milled site is milled in multiple passes. For example, the left milled location 54 is lowered to approximately half the final mill depth. The same mid-depth drill is then performed at right drill location 56 followed by center drill location 58. A second pass is then made to bring the reaming depth to approximately its final depth. A final high speed polishing pass is then performed to ensure a smooth finish for each of the milled locations.

Typically, the disc 52 has a radius between 12.7mm (1/2 ") and 50.8mm (2"). Larger radii reduce flexibility but also cost to manufacture. In a currently preferred embodiment, a 25.4mm (1 ") radius is used. Depending on the material, discs having thicknesses between 2,032mm (0.080 ") and 4.750mm (0.187") can be used. The radius of curvature of each milled location is approximately identical to the radius of disk 52. Therefore, if disk 52 has a one-inch radius, each milled location, left milled location 54, center milled location 58, and right milled location 56 also have a radius of curvature of 25.4 mm (1 ”). The depth of milling is typically 1.010 to 2.032mm (0.040 "to 0.080") for discs between 2.45mm (0.100 ") and 4.750mm (0.187") in thickness.

Each milled location has a “milling distance”. The milling distance is defined as used herein as the perpendicular distance between the edge of the disk 52 and the apex of the milling location 54, 56, 58. In one embodiment, the left and right milled locations 54, 56 have the same milling distance that on a 25.4mm (1 ") radius disc is 0.540". The center milled location has a 0.50 milling distance on a 25.4mm (1 ”) radius disc. It is important that when arranged in the nested pattern, three disks arranged in this way define an arc 60 into which an additional disk can be placed. In particular, a disc that sits on the arc 60 can only be in contact with the milling edge 62 of the discs on which the right and left milling location overlaps. This will depend on the depth of the reaming. In one embodiment, the milling edge 62 has a slight slope as opposed to being exactly perpendicular to the milling surface. This reduces disc cracking during a ballistic event and reduces wear on the milling equipment.

While in one embodiment all discs are identical to disc 52, this leads to a number of milled locations along the end edges (for example, the right edge and the bottom if a left-to-right arrangement is uses, or vice versa, the left edge and bottom if a right-to-left layout is used). The pieces fit together perfectly and there is no significant gap between overlapping discs. Overlapping the pattern shown has been found to effectively spread the force of an impact from a high velocity projectile to adjacent discs, thereby preventing penetration and deformation of the rear. The edges where the discs have milled places that are not overlapped by another disc are considered outside the "protection zone" provided by the armature.

Additionally, due to the slight tilt of each disc in the pattern, a perpendicular impact is highly unlikely and some of the energy will be absorbed in the deflection. Finally, during the ballistic event, the hardness of the material disc tends to expand or dull the projectile tip, resulting in a further reduction in its piercing ability. In particular, the arrangement can be manufactured in any shape such that the zone of protection conforms to the torso or other vital area.

In an alternative embodiment, special finishing discs with fewer milled locations can be used to ensure that a full thickness disc overlaps all milled locations. For example, a lower row of discs can be milled only to allow an adjacent disc to overlap on the lower row, for example, having only one right milled location (for a left-to-right arrangement), and since no other disc will overlap the discs in the bottom row, this will avoid the thin spots in the bottom row.

Figure 3 shows an embedded pattern of discs 52 that is attached to a substrate 80. As discussed above, the substrate 80 can be an adhesive-impregnated polyethylene or aramid fiber fabric. The

ES 2 373 145 T3 suitable fabrics include fabric sold under the trademark SPECTRA® from Allied-Signal of Morristown, NJ, TWARON® microfiliment from Akzo-Nobel of Blacklawn, Georgia, SB31 and SB2, sold under the trademark DYNEEMA, from DSM of the Netherlands, PBO sold under the trademark ZYLON® from Toyobo of Tokyo, Japan, KEVLAR® or PROTERA® from EI Dupont de Nemours & Company of Chattanooga, Tennessee. One skilled in the art will find other suitable fabrics.

Some suitable substrates are available with a corrosive adhesive coating covered by a release liner. In addition to being corrosive, it is important that the adhesive once cured remains flexible to reduce dissociation of the discs and substrate during a ballistic event. The substrate of a desired size can be cut and the release paper peeled off to expose the adhesive surface. The disk can then be arranged directly on the adhesive which holds it in a position relative to one another. Because the substrate is flexible and the discs bend around their intersection, the combo unit is flexible. Alternatively, the pattern can be arranged and the substrate adhered over the top.

As shown in Figure 4, the next step is to place another layer of this adhesive-coated flexible substrate on the other side of the hand-laid coins to fix them in a flexible position that does not change when the panel flexes, such so that even though each coin will pivot away from adjacent coins, the actual position of each coin remains in substantially the same place as it was arranged. This second layer of adhesive fabric that is used to wrap the interwoven pattern provides additional strength capability, thereby reducing the risk of a disc deflecting and the body armor failing.

The NIJ defines various levels of threat. A level three threat is a 7.62 x 51 millimeter, 150 grain (9.72 gram) full metal jacketed projectile traveling at 2700 - 2800 ft / second (823 - 853 m / s). It has been determined that the invention disclosed above will neutralize level three and all minor threats. Additional layers of the adhesive coated flexible substrate may be added to either side in any proportion (i.e. this is within the scope of and it is contemplated in the invention to have more substrate layers to one side of the plate than to the other side of the board) in multiple layers to obtain different performance criteria. Some situations benefit from allowing the coins to shift slightly during the ballistic event, while others make it desirable for the coin to remain as fixed in place as possible.

In an alternative embodiment of the invention, a high tensile strength "dry" flexible substrate is provided. This is then coated with a flexible bonding agent, for example a silicon elastomer resin. The disks can then be arranged as described above. The bonding agent is then cured to flexibly maintain the relative locations of the discs. A similarly coated layer can be used to sandwich the plate from the opposite side. It is also within the scope of the invention, and contemplated therein, the use of a layer with a flexible bonding agent while a facing layer is of the peel and stick variety described above. As used herein, "adhesive impregnated substrate" refers to a suitable flexible high tensile strength material having an adhesive that is set aside, whether it is commercially available with adhesive applied or is coat later as described above.

In yet another embodiment, an adhesive-impregnated substrate is created by one or other of the methods described above and the (interleaving) layer is non-adhesive and merely engages the underlying substrate around the periphery of the plate. This will somewhat degrade the retention of the disc as compared to sandwiched between the adhesive layers. Consequently, this configuration will not survive as many impacts and the face layer that fits around the periphery serves mainly as a protection against small fragments.

Figure 5 is a perspective view of a disk of a second alternative embodiment of the invention. In this embodiment, a flat disk is prepared in the normal way and then slightly curved around an axis that cuts the arc of the central milled location in two equal parts. The bending will normally vary between 2 ° and 15 ° with respect to the horizontal, depending on the dimensions and the curvature of the area to be protected by the reinforcement. This embodiment is most suitable where large discs are used as the light curve, for example 50.8mm (2 ") radius, which allows the discs to better match the contours of the body. This is desirable with large discs because larger discs imply reduced flexibility of the overall assembly. Therefore, from the point of view of comfort, it is desirable to have a curved disc to accommodate the contour and movement of the body. For discs with a radius of 1 ”(2.54 cm) or less, such bending is considered unnecessary and undesirable. Figure 6 is a cross-sectional view of the disk of the embodiment of Figure 5.

Figure 7 is a perspective view of a disk of an alternative embodiment of the invention. In this embodiment, the disk is prepared as described above. After milling but prior to layout, a press is used to concave the disc with respect to the rear which results in the disc being convex in the direction of the milled surface. Figure 8 is a sectional view of the disk of the embodiment of Figure 7. In this view, the concavity is clearly evident. This disc design may have

ES 2 373 145 T3 has improved deflection characteristics versus flat disc and may also improve comfort for some users.

Figure 9 is a front view of a body armor assembly as it may be worn in one embodiment of the present invention. Body armor 110 covers a wearer's torso and is designed to protect vital areas from high velocity projectiles. Flaps 120 in the body armor extend around the wearer's body to extend protection to the wearer's sides. In one embodiment the body armor is wrapped around a segment of the wearer, for example the torso, which provides substantially uniform armor protection on an enveloping circumference.

Figure 10 is a front sectional view of one embodiment of a body armor set. Discs 152 are arranged in an interlocking pattern to cover vital areas where body armor is worn. Unlike the rigid 10 x 12 plates of the prior art, the embedded pattern can flex around the contours of the body and is therefore considerably more comfortable and can also be hidden more easily. Each disc 152 is formed of a high hardness material. In one embodiment, each disc has a circular sheet shape having a maximum thickness in the center of the disc and tapering in thickness toward the outer edge providing one or more downwardly sloping surface segments. In one embodiment, the thickness of the circular sheet-shaped disk decreases at a uniform downward sloping slope relative to the center toward the outer edge. In another embodiment the circular sheet shape has an internal circumference within which the disc has a uniform thickness and slopes uniformly downward between the internal circumference and the circumferential edge of the disc.

Typically the edge thickness will be about half the thickness in the center. In that sense, when arranged in the embedded pattern, the discs show a pivoting capacity that allows flexibility on the order of 60% greater than existing metal plate or coin arrangements. There are many such suitable ceramic materials that are also relatively lighter in weight compared to steel or other high hardness metals.

The tapering cross-sectional design, intrinsic to the circular sheet shape of one embodiment of the invention, renders the disc surface non-planar, which provides a slope to deflect ballistic impacts compared to a flat, uniform planar surface. In this regard, the ceramic composite material can be sintered and / or molded into a circular sheet shape of homogeneous ballistic quality more easily and at a lower cost than can be done with a metal disk, which either has to be turned or machined to produce a similar circular sheet shape whose cross section gradually decreases. However, circular sheet-shaped metal discs are within the scope of the invention and are contemplated therein. Through the suitably shaped arrangement of the discs in an interwoven pattern, the overall body armor 110 remains flexible and also provides good protection against high velocity projectiles.

Additionally, the lighter weight and greater flexibility of the ceramic composite compared to prior art protection against high velocity projectiles allows for greater mobility and range of motion by the user. For example, body armor vests composed of imbricated ceramic discs of ballistic quality hardness and fracture toughness can be wrapped entirely around a segment of the wearer, such as the torso, extending disc protection down to the 360 degrees around the user. The lighter ceramic material also avoids the marked negative buoyancy of high hardness metal coins or plates typical of prior art body armor. This allows for use in the field while swimming or climbing, something for which prior art body armor is not suitable.

Also in this embodiment, to arrange the interwoven pattern, the disks are arranged from the left to the right. Each subsequent row is also arranged from left to right. Switching from left to right, then right to left, has been found to create a weakness in the resulting pattern that often results in failure. The discs within each row form a substantially straight horizontal line. Because the discs overlap, each disc rests on a slight incline relative to a line normal to the horizontal layout surface. In one embodiment, this slight incline of the discs complements their sloping circular sheet shape to increase the probability of deflection from impact.

After the discs are arranged from left to right and top to bottom and sandwiched between a pair of layers of adhesive, the entire pattern is reversed for assembly on the body armor. Most threats have been found to arrive on a downward trajectory. Therefore it is desirable that each row of discs overlap the row below it when the armor is worn. It is, however, within the scope of and contemplated by the invention to arrange the disks in an alternate order, for example from right to left, bottom to top. It is also contemplated that by reversing the embedded pattern in the course of assembly the body armor can be connected such that each row overlaps the row above it.

IS 2 373 145 T3

A number of possible ceramic composites have been found suitable as high hardness materials for discs. These include fiber-induced ceramics sold under the trademarks SINTOX® FA and DERANOX® from Morgan Matroc, Ltd. of Bedforshire, England. In particular, the alumina oxide ceramic SINTOX® FA and DURANOX® D995L, for a zirconia-hardened alumina oxide ceramic composite, which is composed of approximately 88% by weight of alumina plus approximately 12% by weight transformation hardened zirconia (TTZ) have proven to be suitable ceramic composites.

Although alumina-based composites are preferred, other bases can be used to form the ceramic composite including barium titanate, strontium titanate, calcium zirconate, magnesium zirconate, silicon carbides, and boron carbides. As noted, these potential ceramic bases are not limited to oxyceramics but also include mixed oxides, non-oxide materials, silicates as well as MICATHERM® ceramics, (the latter being a trademark for inorganic thermoplastic materials sold by Morgan Matroc, Ltd. of Bedforshire, England).

Suitable ceramic composites will have relatively high hardness and fracture toughness. Typically such materials will have at least about 12 GPa in hardness and at least 3.5 MPa m^1/2 in fracture toughness in order for the armor to withstand a level three ballistic event as defined by the National Institute of Justice (NIJ). A level three threat is a 7.62 x 51 millimeter, 150 grain (9.72 gram) full metal jacketed projectile traveling at 2,700 - 2,800 ft / second (823 - 853 m / s). Ultimately, the levels of hardness and fracture toughness will depend on the type of ceramic composite used. For exemplary embodiments of the present invention using alumina bases, the minimum fracture toughness for alumina would be 3.8 MPa m^1/2 and 4.5 MPa m^1/ for zirconia hardened alumina. The hardness for alumina would be in the approximate range of 12 to 15 GPa, and for zirconia hardened alumina, the hardness would be at least about 15 GPa.

In certain cases, the ceramics used can be supplemented with the addition of a toughening agent such as hardened metal oxides. In one embodiment, TTZ is added to the alumina base. The inclusion of metal oxides increases the strength of the resulting ceramic composite and resists dissociation of the disc upon impact during a ballistic event. For alumina-based ceramic composites, the TTZ weight percent range for suitable ballistic grade ceramics would be between 0.05% and 20%. In one embodiment, the percentage of TTZ by weight relative to the alumina base is about 12% of the composite material.

The ceramics are mixed in ways that are commonly known in the art. Sintering and molding procedures, including injection molding, to form the disk are well known in the art. In one embodiment, the discs can be formed by injection molding and then pressed into the desired shape. Once formed, certain embodiments of the discs are then encased with a containment shell material. This material provides greater integrity for the disc and increases its fracture toughness, consequently increasing its ability to absorb the impact of ballistic projectiles without dissociation. In one embodiment, this wrap is a fiberglass wrap that is adhered by an adhesive substrate. Suitable fiberglass materials include Eglass and S-2 Glass available from Owens Corning Fiberglas Technology, Inc. of Summit, Illinois. Suitable adhesives include modified epoxy resins. The containment shell and epoxy resin substrate can be applied to the disk by high pressure steam curing, or in other ways known in the art. Strength, cohesion and structural integrity can also be imparted by overlaying the disk surface with aramid fibers, in layers or crosswise on an adhesive substrate.

Typically, disc 152 has a radius between 12.7mm (1/2 ") and 25.4mm (1"). Larger radii reduce flexibility but also cost to manufacture. In a current embodiment, a 25.4mm (1 ") radius is used. Each disc decreases its thickness in cross section by varying between its central zone (where the thickness is at its maximum) and its edge (where the thickness is at a minimum). The maximum and minimum thicknesses will vary according to the level of ballistic threat to be neutralized. For example, to neutralize a high velocity ballistic rifle threat, a maximum thickness of 9.53 mm (3/8 ”) can be used in the center whose cross section gradually decreases to a minimum thickness of 7.81 mm (3 / 20 ”) on the edge. A low velocity rifle threat (or a high velocity pistol threat) may require only a thickness of between 3.18 mm (1/8 ") (maximum) and 2.54 mm (1/10") (minimum ). In one embodiment, the circular sheet shaped discs have a center thickness of approximately 1/4 "(6.36mm) and an edge thickness of 1/8" (3.18mm).

The overlap of the imbricated placement pattern has been determined to effectively disperse the force of an impact from a high velocity projectile to adjacent discs, thereby preventing penetration and deformation of the rear. Additionally, due to the slight tilt of each overlapping disc in the embedded pattern, a perpendicular impact is highly unlikely and some of the energy will be absorbed in the deflection. In the circular sheet embodiment, the gradual decrease in thickness in the cross section, which forms a non-planar inclined surface, makes a perpendicular impact extremely unlikely.

Figure 11 shows an interwoven pattern of disks 152 that is attached to a substrate. As analyzed

ES 2 373 145 T3 above, the substrate can be a polyethylene or aramid fiber fabric impregnated with adhesive. The same fabrics that have been discussed above are suitable for use with ceramic discs. The arrangement on the adhesive substrates is also analogous.

Figure 12 is a perspective view of a disk. In this embodiment, the disc has a circular sheet shape of variable thickness, 6.36 mm (1/4 ") in the center whose cross section gradually decreases with a uniform slope to 3.18 mm (1/8"). on the circumferential edge. In an interlocking pattern, the edges of adjacent discs overlap, creating areas of significant thickness that have multiple layers of discs. Normally, this pattern will not overlap in the center, or thickest area, of the disc. Therefore, a projectile striking the pattern of discs at any point will hit either a singular disc near its thickest area, or multiple discs layered at least as thick, and probably thicker, than the thickest area of ​​the disc. singular. Furthermore, the slope of the circular sheet shape between areas of varying thickness discourages any perpendicular ballistic impact.

Figure 13 shows a perspective view of a disk after application of a containment shell. As indicated above, this wrap can be a fiberglass or aramid fiber composite material that adheres to a substrate which can be a modified epoxy resin. The casing imparts increased fracture toughness and toughness, reducing disc fracturing and dissociation in response to a ballistic event.

Figure 14 shows a cross section of a disk illustrating its circular sheet shape. Adhesive layers 122 and containment wrap 124, as noted above, are apparent.

Figure 15 is a perspective view of a disk of an alternative embodiment of the invention. In this embodiment, the formation of the disk is substantially as described above, varying only in the slope of the final result. Although the thickness varies from the center to the edge, the slope of said gradually decreasing cross section is not uniform, leaving an abult more pronounced in the center that is domed in shape. This leaves the surface area extending from the edge of the circumference to the center dome-shaped substantially flat. This embodiment allows the discs to have a greater overlap surface area, which increases the surface area in which a projectile would encounter multiple disc layers. However, the substantially flat area increases the probability of a perpendicular impact. The domed discs can be arranged in a manner analogous to that described above and assembled into body armor capable of neutralizing level three threats.

Figure 16 is a side view of the alternate embodiment shown in Figure 15.