CA2298670A1

CA2298670A1 - Projectile resistant structure

Info

Publication number: CA2298670A1
Application number: CA002298670A
Authority: CA
Inventors: Albert K. Lindstrom; John L. Cummer
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-07-31
Filing date: 1998-07-30
Publication date: 1999-02-11
Also published as: WO1999006785A2; WO1999006785A3; AU8669898A

Abstract

Projectile resistant structure (1) comprises a plurality of stacked flexible shield layers (20). Layers (20) are in general not bonded to one another, so that when a first of such layers is struck by spinning projectile (1) the layer acts without significant structural or other support from any other layers in countering the rotation of the projectile. Preferred shield layers are comprised of anisotropic puncture-resistant materials, stacked such that the principal axes of the layers are offset from each other, and further include substantially soft, impact-dissipating cores (3) disposed adjacent to one or more shield layers so as to spread the force imposed by an impacting projectile across a broader area of the shielded structure or body than would otherwise be affected by the impact. Cores are preferably water-resistant and less dense than water, such that they float and serve to support the shielded structure or body in water.

Description

Title: PROJECTILE RESISTANT STRUCTURE
This application claims the benefit of United States Provisional Application Serial No.
60/054, 379, entitled "Projectile Resistant Structure", filed July 31, 1997.
TECHNICAL FIELD
The invention relates to protective shield structures; more particularly, it relates to soft puncture-resistant armor made of laminated woven light-weight fiber materials for stmctures, including highly adaptable projectile-resistant shield panels, and for vests and other protecti~.-e garments for persons and other living things.
BACKGROUND OF THE INVENTION
It is estimated that worldwide an average of roughly 1000 people have been killed by bullets, bomb fragments, knives, arrows, and other puncture-causing objects or projectiles every single day during the 20th century. Wars have brought terrible casualties, often more civilian than military; law enforcement officers live in perpetual jeopardy; crime takes fearful toll among the peaceful; and political terrorism has provided new depths of horror.
Of these tens of millions dead, many millions could have been saved, with their unique:..
diverse, and sometimes brilliant talents, their love, and their abilities, through the use os puncture- or projectile-resistant protective armor, either in the form of vests or other garments, or eternally as armor for walls, doors, vehicles, and the like.
And the human cost is not ail. Many law enforcement or humanitarian missions have been defeated through the destruction of critical or sensitive equipment by bullets, tra~ments c:,r other projectiles; and many millions of dollars in material damage have been suffered. And as with the waste of human life, much of this material damage could have been averted through the use of puncture- or impact-resistant armor or other protective materials.
Protective materials are not entirely unknown. For example, soft armor material is known which is made from a plurality of fabric layers of light-weight, high strength fibers, particularly aramid fibers, such as those sold under the trademark Kevlar, and polyethelene f bers, such as those sold under the trademark SPECTRA. A typical soft armor material made from such fabric material is typically tailored in the form of a jacket or vest and is used to protect individuals against handgun, shotgun, club and knife assaults. Likewise, attempts at providing protection for persons within structures have been made. For example, Babbaza U.S. Pat. No.
i 0 5, l 64,536 discloses an armor resistant seat primarily utilizing ceramic-matrix composites as the ballistic resistant materials; and Dunbar U.S. Pat. No. 5,200,256 shows a variety of armored lirvngs, each of which employ rigid or relatively inflexible shield layers and in each of which the shield layers are strongly bonded to one another, for use with vehicles of one sort or another.
Even some flexible armors have been suggested. McArdle, U.S. Pat. No.
3,294,038, entitled Fragment Suppression Configuration, provides a protective system which includes a blanket portion composed of at least two layers of ballistic nylon felt interposed with an inner lamination or ply and enclosed with a ballistic nylon cloth envelope. A prime protective surface or layer composed of ceramic or tile assembly incorporates a plurality of individual ~~ightly spaced tiles each mounted with its faceside boned to an overlapping double layer glass cloth and its rearside covered with a separate metal backplate which is bonded with the metal backplate side and overlapping portions of the glass cloth against the faceside of the blanket.
An armored skin-diving. suit is the subject of U.S. Pat. No. 4,356,569 issued to Sullivan; the Sullivan device provides a flexible garment portion with a plurality of armor elements spaced at intervals thereon.
Protective vests constructed of material having projectile stopping capabilities are also known.
An example is shown in U.S. Pat. No. 4,483,020 to Dunn, entitled Projectile Proof Vest. 7'he Dunn device includes a network of rigid inner shock resistant plates lying under a layer of ballistic material, in order to minimize the force imparted by a slowing projectile upon the wearer of the vest. An example of metal armor is seen in U.S. Pat. No. 4,534,266 entitled Composite Armor Plating to Huet. The Huet device provides a composite metal armor comprising ceramic inserts arranged in a regular manner within a metal casing.

Yet there is a continued need for increased stopping power and increased efficiency in projectile-resistant structures. Each of -the devices described above relies upon the use of bonded, typically resin-saturated shield or fabric layers, and many of them incorporate heavy metal, ceramic, or metal-mesh reinforcing plates and layers, none of which are flexible or comfortable, and some of which can cause substantial injury of their own under heavy impact;
inflexibility leads to wearer discomfort in armored apparels and to an inability to adapt prefabricated armor panels in a wide variety of structural uses. None of the devices will float i;~
water, and few of them are adaptable enough to perform alternatively as vests, personal flotation devices, floating structures, armored blankets and portable armored shields, and integral armored construction for the protection of lives, equipment, and property. Nor can these prior devices prevent exit of a projectile at the edges of the protective panels. Moreover, each of the devices requires a great many layers of fabric to be effective in stopping a bullet, particularly if the bullci:
is spinning (as for example a result of being fired from a rifled barrel): the aramid fabric layers of these structures are all bonded together, and structures in which the layers of aramid fiber I S fabric are bonded together tend to permit a spinning bullet to pass through without capturing being captured, and hence are only successful as bullet proof structures by virtue of the use of many more layers than is needed in the present invention.
There is a need for a system which solves these difficulties and provides a strong, lightweight, projectile-resistant, flexible, optionally floating structure adaptable to a wide variety of structural and personal applications, including vests, portable shields.
personal flotation devices, floating structures, and the protection of otherwise unprotected persons, property, and equipment.
DISCLOSURE OF INVENTION
Accordingly, it is an object of the invention to provide a strong, lightweight, projec.tiie-resistant, flexible, optionally floating structure adaptable to a wide variety of structural and personal applications, including vests, portable shields, personal flotation devices, fioating structures, and the protection of otherwise unprotected persons, property, and equipment.

It is a further object of the invention to provide a projectile-resistant structure capable of stopping spinning projectiles, such as spin-stabilized or otherwise spinning bullets or fragments.
It is a further object of the invention to provide a projectile-resistant structure capable of stopping high energy projectiles with fewer shield layers than previously-known projectile-resistant devices.
It is a further object of the invention to provide a projectile-resistant structure which reduces or eliminates the tendency of projectiles to "run" or travel" along the surface of the structure toward an edge of the structure following impact.
It is a further object of the invention to provide any or all of the foregoing structures in light-weight form.
It is a further object of the invention to provide any or all of the foregoing structures in flexible form.
It is a further object of the invention to provide any or all of the foregoing structures in a comfortable form when incorporated in garments or other personal wear.
It is a further object of the invention to provide any or all of the foregoing structures in a form which floats in water or other fluids.
It is a further object of the invention to provide any or all of the foregoing advantages in a personal flotation device.
It is a further object of the invention to provide any or all of the foregoing advantages in a personal flotation device having selectable or adjustable flotation and protective characteristics.
It is a further object of the invention to provide any or all of the foregoing structures in a form in which glues and resins are not required, and in which shield layers are not impregnated or saturated with resins and are not bonded to each other.
It is a further object of the invention to provide any or all of the foregoing structures in a form which provides improved insulation potential for human users.
It is a further object of the invention to provide any or all of the foregoing advantages in a projectile-resistant shield panel adaptable for use with a wide variety of structures, vehicles, and the like.

It is a further object of the invention to provide any or all of the foregoing advantaf,es in a projectile-resistant pontoon adapted for use with marine vehicles and structures.
It is a further object of the invention to provide any or all of the foregoing advantages in a portable projectile-resistant shield.
It is a further object of the invention to provide any or all of the foregoing advantages in a projectile-resistant briefcase.
It is yet another object of the invention to meet any or all of the needs summarized above.
These and such other objects of the invention as will become evident from the disclosur;;
below are met by the invention disclosed herein.
The invention addresses these concerns and provides such a system. The invention provides soft armor protection for both structures and living beings through the use of multiple layers of unbonded protective shield layers comprised of, for example, aramid fiber fabr ics, optionally backed by a relatively soft, impact-absorbent foam layer. The soft foam layer acts to dissipate and spread the impact of a projectile while the unbonded fabric layers capture the projectile, particularly when the projectile is spinning, as in the case of a bullet fired from a rifled barrel.
The composite projectile- or puncture-resistant panel of the invention is generally formed by wrapping one or more layers of relatively soft, energy-absorbent dense, lightweight foam with layers of protective, generally flexible shield material such as aramid fiber fabrics. When shield layers comprised of anisotropic materials or fabrics are used -- as for example aramid fiber fabrics -- preferred embodiments are formed by alternating the bias of successive wrap layers.
This alternation or offsetting of bias orientations in various layers of the shield fabric has beer found, among other things, to discourage or prevent egress of a bullet through unwrapped edges of the panel, or partial capture and "travel" of projectiles along the face of various plies of shic~lr!
material. Wrapping the shield layers around the core, or using the core in conjunction with unwrapped layers on either one or both sides of the core, enhances the performance of the composite panel by putting the core in position to spread the impact of the projectile over a nnic',~
larger area than the projectile would otherwise typically affect, thus reducing or entirely preventing blunt trauma injury and minimizing the number of aramid fabric layers in the construction of the panel. For example, in the case of an embodiment employing a wrapped core, a particularly penetrating projectile might breach an entire outer set of shield layers, or an outer panel of such layers, pass into or through the soft foam core, and be captured by the inner set of shield wraps or by a separate inner panel. The composite shield-laminate and core panel of the invention is adaptable to a myriad of uses including vests, water survival suits, personal flotation devices; portable shields such as projectile-resistant panels and attache cases; vehicle door, wall and roof panels; and bulletproof floats and pontoons for inflatable watercraft and float planes and the like.
One aspect of the invention provides a projectile- or puncture-resistant structure, or panel, comprising a plurality of flexible shield layers or laminae. The individual layers are stacked to form a panel, but are not bonded to each other, though they may and in many preferred embodiments are attached at one or more edges or at their peripheries. It has heretofore been the virtually universal practice, in fabricating laminated armor panels, structures or personal protective devices, to fully bond each of the individual shield layers, or "wraps," of the panels or structures to each other by saturating the layers with adhesives prior to laying them up into panels and allowing the adhesives to set. It has been found as one aspect of the invention, however, that stacking or laying up the layers, or laminae, into panels without bonding the individual layers or laminae together enhances the overall puncture-resistant or projectile-stopping properties of the panel, particularly with regard to spinning projectiles. This is because when a first of the layers in such a panel is struck by the spinning projectile, the fibers of the layer (sometimes broken by the impact) snag or grab the projectile, typically through friction or by actual snagging of irregularities in the surface of the projectile (as for example rifling marks on a bullet fired from a rifled barrel). When individual layers of the panel are not bonded to each other, the layers are free to move and more firmly grasp and slow the projectile until it stops, particularly if one or more of the outer layers are actually pierced and the projectile is engaged by inner layers, each of which acts in the same manner to slow and stop the projectile. Ln addition, unpierced layers of shield material act in more conventional manner to stop tYce projectile through tensile action along the fabric fibers. It has been shown through tests that the stopping power of panels according to this aspect of the invention is superior to conventional bonded pmels, and that penetration of panels according to the invention, particularly by spinning projectiles, is less likely than their conventional counterparts under similar conditions and utilizing similar numbers and types of shield layers.
Generally preferred embodiments of the protective, projectile- or puncture-resistant shield aspect of the invention are comprised of anisotropic puncture-resistant materials. As is well known, anisotropic materials are those which exhibit different characteristics, as for example stiffness or ultimate tensile or shear strength, in various directions. Such materials are said to posses structural "biases" in those directions. For example, many composite materials are composed of substantially-aligned fibers of great strength and high tensile modulus. Such materials are extremely strong and extremely stiff along the axis of their aligned fibers, and exhibit substantially lower strength and stiffness in other directions. The axes of greatest strength and stiffness in anisotropic materials are typically referred to as the "principal axes" of the material. Many aramid fiber fabrics exhibit such anisotropic characteristics, or "bias," due chiefly to the manner in which they are woven; the "warp and weft" of their weave provides distinct properties in various directions. In embodiments of the invention comprising shield layers made of such materials, it has been found that stacking layers of the material so that the principal axes or the "bias" directions of two or more of the various layers are rotationally offset from each other offers significant advantages for slowing and stopping projectiles or other puncturing or piercing objects, particularly when the projectiles or objects are spinning. Fur example, it has been observed that spinning projectiles such as bullets fired from rifled barrels have a tendency, when striking panels comprised of layers of anisotropic materials, to spin along the fabric either with or across the weave, and thus to travel or "run" along or parallel to the surface of the various shield layers toward the edge of the panels, sometimes exiting the panels at an edge. It has been found that when bullets strike panels composed of the same materials with the principal axes of the various layers rotationally offset from each other, this tendency <;an be reduced or altogether eliminated. In particular, it has been found advantageous in preventing this "traveling" of such projectiles to offset the principal axes of the various layers by angles of at least approximately 30 degrees, with best results being observed when alternating layers are offset at approximately right angles, or 90 degrees. For example, in a twenty-ply (or ten-wrap, generally there are two plies per wrap) panel it has been found to be particularly advantageous to align the principal axes, or biases, of the first, third, fifth, seventh, and ninth wraps, and to ~a_v the second, fourth, sixth, eight, and tenth wraps with their axes, or biases, aligned at right angles to the others. Panels constructed with such orientations of their anisotropic layers have exhibited great strength and penetration resistance, and a marked tendency to reduce or eliminate travelling or running of projectiles after impact.
A further aspect of the invention is the provision within the shield panel of a substantially soft, impact-dissipating core. The core may be disposed next to or among any of the individual shield layers. In preferred embodiments the core is disposed between shield layers, either by stacking up individual layers or by wrapping continuous shield material around the core. Ur;e of the functions of the core is to absorb the impact of a projectile or other object striking the individual shield layers and to both dissipate and spread the impact through the shield layers and ultimately to the structure or person supporting the shield, with a minimum of blunt-trauma type injury resulting. In preferred embodiments of the invention the core is made from relatively soft, flexible, light-weight material such as lightweight dense foams derived from various materials, including plastics. Light-weight, water-resistant fibers being well known and generally available, the core may be used to provide yet another advantage: when fabricated of water-resistant materials (i.e. those which do not readily absorb water) less dense than water (either fresh or salt water), the core can be used to both protect and support persons or objects in the water or other fluids, as for example in the fabrication of personal flotation devices or pontoons, floats, or the like.
2.0 Thus another aspect of the invention is a personal flotation device designed for wear by human beings, and in particular human beings possessing both a torso and a head. Preferred embodiments of such flotation devices comprise one or more protective panels of the typ;~
described above, with pluralities of flexible shield layers stacked with or wrapped about a substantially soft energy absorbent core, typically water-resistant foam of lesser density than water. The cores of such devices need not be sandwiched between shield layers, but may lie next to a set of such layers, preferably on the side of the panel closest the wearer of the device. The panels of such devices are fabricated to cover and fit the torso of the wearer in the manner of a vest, and thus to provide coverage to most or a substantial portion of the wearer's torso. Tl~us flotation devices according to this aspect of the invention may serve the dual purpose;. eon protecting the wearer from projectiles or other potentially dangerous or penetrating objets, aad of keeping the wearer afloat, either in water or (if constructed of suitable materials) in other liquids. Such devices may also be adapted to protect the wearer from heat or cold, by the selection of suitably-insulating core and shield layer materials.
It has been found that great advantage may be gained by providing personal flotation devices or other protective garments according to the invention with auxiliary panels adapted for selective attachment to one or more various locations on the main flotation panel(s). Preferred embodiments of these auxiliary panels comprise a plurality of flexible ~'iield layers and a substantially soft energy absorbent core, in the manner of other panels according to the invention, the core being disposed either next to the shield layers or between any two of them in a manner generally similar to the primary panel(s), and may be configured in any of the general forr.~s described herein, including by providing cores composed of water-resistant materials less dense than water, so that they may aid in supporting a wearer in the water. By allowing selective and/or adjustable attachment of such auxiliary panels to the main panels) or to such panels' earner both the flotational and puncture-resistant / protective characteristics of the device may be tailored with relatively great precision to accomplish a broad range of purposes. Selective positioning and adjustment of auxiliary panels is accomplished in a number of ways, as by means of snaps, buttons, zippers, hook and loop fasteners, or other conventional means.
It has further been found advantageous to adapt personal floatation devices according to the invention such that a portion of the panel is disposed behind the wearer's head, so as to provide additional flotational support and impact protection to the wearer while the device is worn. Typically this may be accomplished by extending the rear portion of the main panel upward behind the shoulders and neck of the wearer until it extends all or part of the way behind the wearer's head. Preferred embodiments of this aspect of the invention further take advantage.
of such configurations by adding a handle to the neck or head portion of the vest to facilitate carriage and handling of the flotation device.
Panels according to the invention may be put to a wide variety of protective uses. For example, such panels may be employed with or without cores as moveable, easily installable protective panels in cars (particularly in car doors, roof liners, carpets, and the like), aircraft (including helicopters), boats, and other vehicles; in podiums and other structures; as "bomb blankets", or free panels used to cover potentially explosive devices or to provide moveab!~;

WO 99/Ob785 PCT/US98/15743 cover, or as bulkhead shields for aircraft cargo holds and the like; or as integral or removable seat cushions. They may be mounted permanently or impermanently, by means of any suitable conventional fasteners, such as screws, rivets, snaps, etc., or hook-and-loop fasteners; a.nd they may be encased as integral pants of a structure or hung bare on walls, bulkheads, or partitions.
Groups of individual panels may even be used by besieged or otherwise threatened individuals to construct small, temporary protective enclosures in times of need. The details of th;:, fabrication of shield panels, roof liners, seat covers, bomb blankets, and the like according to the invention, beyond those critical details disclosed in this specification, will be well known in the art and well within the ability of the skilled designer of protective devices once he or she has been armed with the disclosure of the invention.
A specific and particularly advantageous use to which core-employing panels accordintY
to the invention may be but is the construction of impact-, puncture, or projectile resistant pontoons and floats for boats, planes, and the like. Preferred embodiments of this aspect of the invention comprise a core having an outer surface, a plurality of shield layers, and a coveriric;.
The core is typically water-resistant and less dense than water, as described above. The pturality of shield layers being wrapped about the outer surface of the core, optionally with the offset bias or principal axis of~'set discussed above; the layers may be wrapped many thicknesses deep. 'fhz covering is typically disposed about the shield outer layer, for structural support of the pontoon and protection of the pontoon from exposure to weather and the environment in which it is used.
For example, different coverings may be required for various operations in mining slag pools than fresh water; the selection of proper covering materials will involve many factors. such as exposure to ultraviolet rays, sunlight, heat, water, minor impacts, or other enmronmental factors.
The evaluation of such factors and the selection of an appropriate covering material is well within the ken of the ordinary designer of such pontoons, once he or she has been armed with the disclosure of the invention. As generally described above, the shield layers in such a protective structure are preferably not bonded to each other, so that when a first of such layers is struck b~:
a spinning projectile the layer acts without significant structural support from any other layer in countering the rotation of the projectile. Moreover, they are typically comprised o' acusotropic puncture-resistant materials and are wrapped so that the principal axes of at least two of the layers are rotationally offset from each other, preferably by angles ranging fro~a w0 99/06785 PCT/US98/15743 approximately 30 degrees to substantially normal or perpendicular (90 degrees). Cores according to this aspect of the invention may be provided with auxiliary reinforcement, either by means of the shield layers or the covering, or by means of internal reinforcement, such as integrally provided re-bar or structural framing.
It is anticipated that preferred embodiments of any of the various panel aspects of the invention discussed will be used in conjunction with panel covers. Such covers are generally intended for use in deploying and protecting shield panels. For example, in a personal flotation device according to the invention, a cover may advantageously be employed to help fit the flotation device to its wearer, and to hold it in place, and to support straps, attachments, pockets, insulating layers, etc., as well as to protect the shield panels and core from exposure to the elements and from damage. Likewise, a cover for a moveable shield panel may be employed to mount the panel, to hang it on a wall, or for identification, visibility, or marketing purposes as well as protection of the panel itself. The selection of appropriate materials for such structures, will, again, be well within the ability of one skilled in the relevant art.
Another aspect of the invention involves a specific application of the shield panel aspect of the invention in providing a portable projectile-resistant shield.
Preferred embodiments of this aspect of the invention comprise one or more protective panels, according to the foregoing, and a briefcase. the briefcase being sut~icient in size to cover a substantial portion of a typical human torso, so that it may be held before one's body and used to shield the user, and particularly the user's vital organ cavity, ti-om projectiles or unwanted impacts. Generally the method of using tl-us shield aspect of the invention is to dispose the shield panel inside the briefcase somewhere, as along one of the larger sides or in a liner of the briefcase, and to hold it up, when threat~n~d, before the body so as to interpose it between the user and any unwanted potentially impacting objects. One way of stating this is to say that the briefcase shield is typically izeld out before its user so that the briefcase is generally perpendicular or normal to a ray emanating from the center of the user's torso, which generally has the effect of placing the shield layer substantially perpendicular to the line of travel of potentially impacting objects, so that the shield rr~ay most effectively stop, slow, or deflect them. Preferred embodiments of this aspect of the invention employ briefcases at least 13 "x 17" in major dimension (this having been found to be sufficient to cover most human vital organ cavities), with shield panels suitably sized to fit, depending .gin the application to which the shield is to be put.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a preferred embodiment of the invention being struck by a projectile.
Figure 2 is a schematic view of a preferred embodiment of a plurality of anisotropic shield layers according to the invention.
Figures 3a and 3b are schematic cutaway views of a preferred embodiment of a projectile resistant structure aspect of the invention being struck by a projectile.
Figure 4 is a schematic view of a preferred embodiment of the personal flotation device aspect of the invention.
Figure 5 is a perspective view of a preferred embodiment of the personal flotation device aspect of the invention.
Fi~,rure 6 is a perspective view of a preferred embodiment of the personal flotation devic,:
aspect of the invention.
Figure 7a is a perspective view of a preferred briefcase embodiment of the portable projectile resistant shield aspect of the invention. Figure 7b is a cutaway view of a preferred briefcase embodiment of the projectile resistant shield of the invention.
Figures 7c, 7d., and 7e are schematic views showing the sizing and use of a briefcase embodiment of the projecti~w resistant shield of the invention.
Figure 8 is a perspective view of a preferred pontoon embodiment of the projectii;
resistant structure aspect of the invention.
Figures 9a and 9b are perspective views of marine applications of preferred embodiments of shield aspects of the invention.
Figure 10 is a perspective view of several preferred embodiments of the projectiir~
resistant shield aspect of the invention incorporated in an automobile.
Figure 11 is a perspective view of several preferred embodiments of the projectile resistant shield aspect of the invention incorporated in an aircraft.

Figure 12 is a perspective view of a preferred embodiment of the projectile resistant shield panel aspect of the invention. -BEST MODE OF CARRYING OUT THE INVENTION
When used in this specification, the term "projectile resistant" means having an ability or tendency to resist puncturing, impact, and other damage caused by ballistic and thrusted or otherwise propelled objects, such as for example bullets, knives, arrows, shrapnel, and fragment.
For purposes of the specification the term is interchangeable with the terms "impact resistant"
and "puncture resistant."
To say that two or more shield layers are "bonded" to each other means, within the meaning of this specification, that the layers are field-glued, resined, fizsed, epoxied, cemented, adhered, or otherwise broadly, globally or generally fixed, stitched, or sewn, or otherwise mechanically fastened to one another, or adapted so as allow shear load transfer from one bonded part to another, over a significant portion of their surfaces. Being glued, sewn, hemmed, seamed, or otherwise fixed or secured at one or more edges or at a periphery for the purpose of securing or completing a group of layers as a panel, a segment of a panel, garment or like device is not "bonded" in this sense. For example, in a personal floatation device according to the invention the edges of individual shield panels are typically sewn together, in order to allow the panels to retain their proper shape, but the panel layers are not, for purposes of this disclosure, considered bonded because of it.
Turning now to the drawings, the invention will be described in a preferred embodiment by reference to the numerals of the drawing figures wherein like numbers indicate like parts.
Figure 1 is a perspective view of a preferred embodiment of the invention being struck by a projectile. Projectile 1, depicted as a bullet, has been fired in the direction of arrow 40 and is spinning in the sense shown by arrow 41. Shield layers 20 are stacked against each other but are not bonded together, with the result that when projectile 1 strikes first or outermost shi~l~_i layer 2 and (in the case depicted, but of necessity) breaks several of fibers 21 of first shield lay;~~.r 2, both broken and unbroken fibers grab or snag the projectile such that continued spinning of the projectile places the fibers in tension, as indicated by arrows 42, causing them to resist thL
spinning. Because shield layers 20 are not bonded to each other, they are relatively free tees deflect, or even bunch together in response to the tension induced in the individual fibers. adding the work of the layer-displacement to work done by the shield layer in countering the rotation of the projectile. To the extent that the projectile breaches the first layer and proceeds to contact second layer 30, the process is repeated, with several of fibers 21 in the second layer snagging the projectile, placing the fibers in tension and causing the layer to bunc.:.
>vloreover, any additional, unbreached layers act in more conventional manner to resist penetration of the projectile, the fibers of such panels being placed in tension by the attempted passage of projectile 1. 'The action of slowing or stopping the spinning of the projectile in this manner contributes to the greater efTrciency of the invention than previous protective shields, permitting projectiles to be stopped with fewer layers than previously possible due to bonding of the various shield layers to each other.
Figure 2 is a schematic view of a preferred embodiment of a plurality of anisotropic shield layers according to the invention. The four anisotropic puncture-resistant shield layers 45 any?
46 are comprised of fibers 21 bound together into sheets or layers 20 by means of binders 22.
1 ~ Both because fibers 21 generally have greater tensile stiffness and strength than binders 22 and because of the geometry of the construction of the layers 20, layers 20 exhibit much greater strength and stiffness in a direction parallel to their respective fibers 21.
That is, the two layers 45 exhibit greater stiffness and strength in the direction of arrows 44 than in the direction ef arrows 43, while the two layers 46 exhibit greater stiffness and strength in the direction of arrows 43 than in the direction of arrows 42. Thus layers 46 may be said to possess principal axes, or to be structurally biased, in the direction of arrows 43, while layers 45 may be said to posses principal axes, or to be structurally biased, in the direction of arrows 44.
In the Figure layers 4~
and 46 have been stacked alternately so that angle 47 between the principal axes (or the "bias"1 of alternate layers is approximately 90 degrees, and alternate layers are laid down with substantially normal or perpendicular biases. It has been found that stacking the layers with substantial offset between the bias or principal axes helps greatly in preventing the "running" or "traveling" of bullets along the surface of the shield layers. Any substantial offset will suffice, from approximately 30 degrees and up, with excellent advantage and generally superior "nrn"
stopping performance occurring at approximately 90 degrees offset.

Figures 3a and 3b are schematic cutaway views of a preferred embodiment of a projectile resistant structure aspect of the invention being struck by a projectile.
Projectile-resistant structure 30 is comprised of laminated shield 23 and substantially soft, impact-dissipating cere 3. Core 3 is enclosed in wrapped laminated shield 23 comprised of a plurality of individual shield layers 20, and thus disposed between two portions of the same innermost continuous shield layer.
In many embodiments core 3 is not fully wrapped in laminated shield 23, but simply disposed next to an outer shield layer. In the Figure projectile 1 is shown prior to and following impact with outer shield layer 2 (on impact the projectile has flattened and its shape has been deformed).
Laminated shield 23 has absorbed much of the impact of the projectile, spreading the resultant toad through its individual layers 20 by means of tension, as shown by arrows 48, and into cure 3, which has absorbed much of the impact and spread or dissipated the impact (as shown by arrows 49) through the core and into the supporting structure or the wearer's body, so that the blunt trauma experienced by or induced in any structure (or body) supporting projectile-resistant structure 10 by projectile 1 will be spread over as wide an area as possible and minimized.
Preferred materials for fabrication of the shield layers of the invention include polymeric aromatic amide (polyaramid) fiber-based fabrics (such as that marketed under the tradename KEVLAR) and extended-chain polyethelene (ECPE) fiber fabrics (such as that marketed under the tradename SPECTRA). For substantially soft, impact-dissipating cores, and in particular for those cores intended for use in personal flotation devices according to the invention, relatively soft, water resistant, flexible, light-weight but dense material such as foams d:~ived from various materials, including plastics are used. Preferred materials for use in fabricating cores according to the invention include closed-cell cross-linked polyethelene, or polyethelene / EVA foams with fine cell molecular structure; in particular, the foams marketed under the designation Dupont MC 1900 Microcell Poiyethelene EVA foam or the tradename ENSOLITE. Wrapped-core shield panels according to the invention and capable of stopping most handgun-fired bullets have been fabricated using as few as 10 wraps of Poly (P-Phenylene Terephthalamide) Aramid I29, Lincoln Fabrics Ltd. Style #33b3 KEVLAR (a nominal 28x28 fiber weave) wrapped atop one-inch thicknesses of MC 1900; preferred embodiments of the invention have used between 3 and 25 shield layers of such materials on a one-inch core. However, the penetration-resist~rt characteristics required of a given shield panel will vary, depending upon the use to which ahe *rB

WO 99/06785 PCT/US98/15'743 panel is to be put and the types of penetration it is intended to prevent. A
wide variety of materials will be well suited to various environments and threats. Once the inventor has bee.o armed with the disclosure of the invention, an undue amount of experimentation will not k;L.
required before a suitable combination of numbers and types of shield layers and cores will bP
found; at most the making of a few prototypes according to the invention will be required, wioh testing. Covers for many embodiments of the shield panel and other aspects of the invention may be made from a wide variety of materials, including canvas, cotton, nylon, robber, neoprene, <Fr»:1 various polymers and synthetic materials. The selection of proper cover materials will dep~sr:d upon the use to which a particular application is to be put, and the environment in which it is to be used, and will lie well within the ability of the ordinarily-skilled desige. ~r armed with the disclosure of the invention.
Fi~,n,rre 4 is a schematic view of a preferred embodiment of the personal flotation device aspect of the invention. The device is shaped to fit the torso and protect the rear of the head of a human wearer and to allow the arms of the user pass through indentations 55 in the periphery I5 of the device, so that the wearer may be simultaneously both protected and free to move willus~:s undue restraint. Covering 50 covers both front panel 51 (shown dark in the Figure) and rear panel 52. Front panel 51 is designed to substantially cover the chest and front are of the wearer, and is fitted with selectively removable and attachable auxiliary panels 54.
Panel 51 is constructed in the manner described elsewhere herein, with a substantially soft, liquid resiytar~t, floatable core covered front and back with, preferably, at least 10 individual shield layers of KEVLAR or SPECTRA. The cores (not shown) of front panel 51 and rear panel s?
are bctiv water resistant and much lighter than water. The thickness of the core varies in accordance wit::
the core material used and with the uses to which the flotation device is to he put. It has been found that in devices designed for the support of adult humans in water a two-inch (2") thickness of core material in the front panel gives excellent results, including both protection of the wearer from projectiles or other potentially penetrating objects and the provision of substantial buoyancy. Auxiliary panels 54 are attached to cover 50 in the front panel area by means of h;.:ol:.
and loop fasteners, as drawn, but may be attached by any permanent or detachable mechanisnn known to the designer (although impermanent, renewable fastening is preferred). Thev :~r,:.
depicted in "normal" wear positions at the bottom of the front of the flotation device, at ahuu=, waist level of a typical wearer or user of the device. For maximum user protection front panel 51 is integrally formed with rear panel- 52. In preferred embodiments rear panel 52 also incorporates a substantially soft., water resistant, buoyant core (not shown) covered or wrapped with at bast 10 individual shield layers; however, the rear panel core is generally substantially thinner than the front panel core, as it has been found that the provision of greater buoyancy in the front of such devices is generally an aid to wearers in the water. Thus, for example, where the front panel core has a thickness of two inches (2"), a one-inch ( 1 ") core is typically found sufFrcient for the back, both for flotation and projectile-stopping purposes.
The device is donned by wrapping it around the torso of the user with his or her arms extending through indentations 55 between the front and rear panels; fastening shoulder straps 56, which are secured on the front by hook-and-loop fasteners 59 and sewn permanently to the rear cover;
fastening side fastener 57 (shown as hook and loop) and optional crotch support 58 (in the manner of the shoulder straps). Optional handle 9 is provided on head portion 53, typically by sewing the handle to the cover. The outside of cover 50 may also optionally include pockets 60 (see Figures 5 and 6) for carrying emergency supplies and equipment, such as food, flashlights, whistles, and the like.
Figures 5 and b are perspective views of a preferred embodiment of the personal flotation device aspect of the invention, and illustrate use of auxiliary panels 54. In Figure 5 the panels are shown in a "stowed" position, with their bottom edges approximately even with the bottom edge of the flotation device, allowing maximum freedom of movement to wearer 99. In Figur;;
6, the auxiliary panels are deployed downward, providing impact- or projectile-resistant protection and additional flotation in the region of the wearer's hips, legs and lower abdomen.
The auxiliary panels are depicted as attached to the flotation device by means of hook and 1001 fasteners, mating parts 59 of which are located over a wide portion of cover 50 to allow maximum flexibility in their deployment, and therefore in protective and flo~ational options for the wearer. With adaptable fasteners such as hook and loop fasteners, auxiliary panels rrmy ~:vc~n be turned sideways, as shown for the middle panel in Figure 6.
Figure 7a is a perspective view of a preferred briefcase embodiment of the projectile resistant shield aspect of the invention. Figure 7b is a cutaway view of a preferred briefcase embodiment of the projectile resistant shield of the invention. Briefcase 70 has compartments Vt~O 99/(16785 PCT/US98/15743 71 sized to accommodate protective or shield panels 5, one on each side of the case. Panels 5 comprise multiple shield layers 21 wrapped about cores 3 and covered by protective cover S0;
they are placed within compartments 71 to form a portable projectile- or impact-resistant shield.
Optionally, one or more of panels 50 may simply be placed inside briefcase 70 and used in the same way. Figures 7c, 7d, and 7e are schematic views showing the sizing and use of a briefcase embodiment ofthe projectile resistant shield ofthe invention. As shown in Figure 7c, it has been found that the vital organ cavity, including the ribcage, throat, and upper abdomen and spinal column, of most human beings may be covered by a panel measuring approximately 13 inches by 17 inches (see rectangle 97). One of the purposes of the briefcase portable-shield aspect of the invention is to protect the organ cavity of its user; thus a preferred size for briefcase shields according to the invention is at least 13 by 17 inches. In Figure 7d it is shown that a briefcase of preferred dimensions may also be used to shield the organ cavity from the side. In Figure 7e user 98 is shown holding briefcase shield 70 to his chest in order to protect his organ cavity.
Figure 8 is a perspective view of a preferred pontoon embodiment of the projectile-resistant structure aspect of the invention. Pontoon 80 is suitable for emple~ment with a boat, aircraft, or any other floating or marine structure, or on its own as buoy or float. Pontoon 80 comprises cover 50 over a plurality of shield layers 20 wrapped around core 3, which may optionally comprise integral or embedded reinforcing structures, as will occur to those skilled in the art of designing marine structures. Attachments 6 are provided for attaching the pontoon to a structure, and if present may take any number of conventional forms, such as weld tabs, gussets, brackets, etc., attached by any conventional mechanical means.
Figures 9a and 9b are perspective views of marine applications of preferred embodiments of shield aspects of the invention. Figure 9a shows small boat 82 incorporating pontoons 80 to provide primary flotation; in addition, panels 5 have been placed in various locations abouT
control center 81 to protect operator 98. Panels 5 may be incorporated by means of conventional construction techniques inside the structure, or may be attached directly to bulkheads, wall, floors (or decks), or overheads by other conventional means.
Figure 9b shows panels 5 used in similar fashion to protect high-occupancy regions of power boat 83. Another advantage afforded by the invention is that, in addition to increasing projectile and impact protection and providing buoyancy, panels 5 comprising foam according to the invention may also be used to provide thermal insulation, as will occur to skilled structural designers and architects. -Figure 10 is a perspective view of several preferred embodiments of the projectile resistant shield aspect of the invention incorporated in an automobile.
Automobile 10 has several shield panels 5 attached to doors 84. As with the boats of Figure °, panels S may b.
incorporated within or attached to the structures of automobile 10, using any suitable conventional technology. In addition to passenger cars, shield panels 10 might be incorporated in light or armored military vehicles, in armored cars used by banks, ete., in delivery vans, or in a wide variety of vehicular applications. Floors, doors, roofs, trunks, engine compartments, and other automotive features may be protected.
Figure I i is a perspective view of several preferred embodiments of the projectile resistant shield aspect of the invention incorporated in an aircraft. Aircraft 85 incorporates shield panels 5 to protect pilots 98 in a similar manner to uses described in Figures 9 and 10. As in any other structural applications, shield panels S may be employed to protect sensitive or important structure or equipment as well as people; for example, in vehicles and the like shield panels might be employed to protect computer installations or other electronic equipment, such as radios er radar; or, for example, in a passenger airliner they may be used to line aircraft cargo holds or other relatively high-risk locations in order to protect vital structure from internal or cargo explosions, terrorist acts, and the like.
Figure 12 is a perspective view of a preferred embodiment of the projectile-resistant shield panel aspect of the invention, and shows a preferred construction of such a panel. A
plurality of shield layers 20 have been wrapped in the direction of arrows 31 around a double-layer of impact-absorbent core 3, and cover 50 encompasses the entire assembly. As shown in the picture, several laminations of shield layers may be produced by means of a single physic l length of shield layer fabric or material, wrapped about on top of itself, and ultimately sealed o=.' seamed at one or more edges to keep the shield layers in place during service.
In embodimen~a employing anisotropic shield layers, full advantage may be taken of the biased or principal characteristics of the properties of the anisotropic layers by wrapping to several layers' thickness;
as shown in the Figure, using one or more separate lengths of shield material or fabric, adding one or more additional layers by wrapping in an orthogonal direction (indicated in the Figure bar arrows 32) and, if desired, adding still fu --rther layers in the original or any other direction.
With regard to systems and components above referred to, but not otherwise specified or described in detail herein, the workings and specifications of such systems and components and the manner in which they may be made or assembled or used, both cooperatively with each other and with the other elements of the invention described herein to effect the purposes herein disclosed, are all believed to be well within the knowledge of those skilled in the art. _Na concerted attempt to repeat here what is generally known to the artisan has therefore been made.
In compliance with the statute, the invention has been described in language more or leis specific as to structural features. It is to be understood, however, that the invention is nor limited to the specific features shown, since the means and construction shown comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims, appropriately interpreted in accordance with the doctrine of equivalents.
IS
INDUSTRIAL APPLICABILITY
The invention has applicability to the field of protective shield structures, and in particular to soft armor made of laminated woven light-weight fiber materials. It provides imprc~~ed protection for people and other living things, for sensitive or rare equipment, and for any oti;er items under substantial risk of damage due to impact or projectiles.

Claims

I claim:

1. A projectile resistant structure, the structure comprising a plurality of flexible shield layers, the layers being stacked but not bonded to each other, whereby when a first of such layers is struck by a spinning projectile the layer acts without significant structural support from any other layers in countering the rotation of the projectile.

2. The structure of Claim 1, wherein the shield layers are comprised of anisotropic puncture-resistant material, each shield layer having a principal axis; and the layers are stacked so that the principal axes of at least two of the layers are rotationally offset from each other by at least approximately thirty degrees.

3. The structure of Claim 2, wherein at least two of the layers are rotationally offset from each other by approximately ninety degrees.

4. The structure of Claim 2 or 3, wherein the shield layers are comprised of polyaramid fiber-based fabrics.

5. The structure of Claim 1, 2, or 3, further comprising a substantially soft impact-dissipating core, the core being disposed between any two of the shield layers.

6. The structure of Claim 5, wherein the substantially soft energy absorbent core is water-resistant and less dense than water.

7. A personal flotation device for wear by a human being having a torso and a head, the device comprising a flotation panel adapted to support the human in water, the panel comprising a plurality of flexible shield layers adapted to shield a substantial portion of the torso and a substantially soft energy absorbent core, the core being disposed adjacent to any of the shield layers and being water-resistant and less dense than water, whereby the human being may with support of the panel float in water.

8. The device of Claim 7, further comprising at least one auxiliary panel selectively attachable to at least one location on the flotation panel, the auxiliary panel comprising a plurality of flexible shield layers and a substantially soft energy absorbent core, the core being disposed between any two of the shield layers and being water-resistant and less dense than water.

9. The device of Claim 7, wherein at least a portion of the panel is adapted for disposition behind the head of the human being, thereby to provide flotational support to the head in water.

10. The device of Claim 9, wherein the portion of the panel adapted for disposition behind the head comprises a carrying handle.

11. The device of Claim 7, wherein none of the layers is bonded to another layer.

12. The device of Claim 7, wherein the shield layers are comprised of anisotropic puncture-resistant material, each layer having a principal axis, and the layers are stacked so that the principal axes of at least two of the layers are rotationally offset by at least approximately thirty degrees with respect to each other.

13. The structure of Claim 12, wherein the shield layers are comprised of polyaramid fiber-based fabrics.

14. A projectile resistant shield, the shield comprising a briefcase, the briefcase being sufficient in size to cover a substantial portion of a human torso having a center when the briefcase is disposed before the torso; and a protective panel, the panel comprising a plurality of flexible shield layers and a substantially soft, energy absorbent core, the core being disposed between any two of the shield layers, none of the layers being, bonded to another layer;
the protective panel being disposed inside the briefcase such that the plurality of shield layers is substantially normal to a ray emanating from the torso center when the briefcase is disposed before the torso.

15. A projectile-resistant pontoon for a floating vehicle, the pontoon comprising a core having an outer surface, a plurality of shield layers, and a covering;
the core being water-resistant and less dense than water;
the plurality of shield layers being wrapped about the outer surface of the core, so that after wrapping they comprise a shield outer layer;
the covering disposed about the shield outer layer.

16. The pontoon of Claim 15, wherein the plurality of shield layers comprises one or more layers of shield fabric wrapped around the core and again onto itself but not bonded to any shield layer, whereby when a first of such layers is struck by a spinning projectile the layer acts without significant structural support from any other layers in countering the rotation of the projectile.

17. The pontoon of Claim 15, wherein the shield layers are comprised of anisotropic puncture-resistant material, each shield layer having a principal axis; and the layers are wrapped so that the principal axes of at least two of the layers are rotationally offset from each other by at least approximately thirty degrees.

18. The pontoon of Claim 17, wherein at least two of the layers are rotationally offset from each other by approximately ninety degrees.

19. The structure of Claim 17 or 18, wherein the shield layers are comprised of polyaramid fiber-based fabrics.

20. A projectile-resistant panel comprising a substantially soft, impact-dissipating core haying an outer surface, a plurality of shield layers, and a covering;
the plurality of shield layers being wrapped about the outer surface of the core, so that after wrapping they comprise a shield outer layer;
the covering disposed about the shield outer layer.

21. The panel of Claim 20, wherein the plurality of shield layers comprises one or more layers of shield fabric wrapped around the core and again onto itself but not bonded to any shield layer, whereby when a first of such layers is struck by a spinning projectile the layer acts without significant structural support from any other layers in countering the rotation of the projectile.