U.S. patent application number 11/187550 was filed with the patent office on 2007-02-08 for composite armor plate and ceramic bodies for use therein.
Invention is credited to Michael Cohen.
Application Number | 20070028757 11/187550 |
Document ID | / |
Family ID | 34073794 |
Filed Date | 2007-02-08 |
United States Patent
Application |
20070028757 |
Kind Code |
A1 |
Cohen; Michael |
February 8, 2007 |
Composite armor plate and ceramic bodies for use therein
Abstract
The invention provides a composite armor plate for absorbing and
dissipating kinetic energy from high-velocity projectiles, the
plate comprising a single internal layer of pellets which are bound
and retained in plate form by an elastic material, substantially
internally within the elastic material, such that the pellets are
bound in a plurality of spaced-apart rows and columns, the pellets
being made of ceramic material, and the pellets being substantially
fully embedded in the elastic material so that the pellets form an
internal layer, wherein the solidified material and the plate are
elastic, and wherein a majority of each of the pellets is in direct
contact with six adjacent pellets in the same layer to provide
mutual lateral confinement therebetween, each of the pellets being
characterized by a body having a substantially regular geometric
cross-sectional area and first and second end faces, each of the
end faces projecting from the body and having an outwardly
decreasing cross-sectional area wherein the height of the end face
disposed substantially opposite to an outer impact receiving major
surface of the plate is less than 15% of the length of the diameter
of the pellet body from which it projects.
Inventors: |
Cohen; Michael; (Mobile Post
North Yehuda, IL) |
Correspondence
Address: |
FULBRIGHT AND JAWORSKI LLP
555 S. FLOWER STREET, 41ST FLOOR
LOS ANGELES
CA
90071
US
|
Family ID: |
34073794 |
Appl. No.: |
11/187550 |
Filed: |
July 22, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10937205 |
Sep 8, 2004 |
|
|
|
11187550 |
Jul 22, 2005 |
|
|
|
Current U.S.
Class: |
89/36.02 |
Current CPC
Class: |
F41H 5/0414 20130101;
F41H 5/0492 20130101 |
Class at
Publication: |
089/036.02 |
International
Class: |
F41H 5/02 20060101
F41H005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2003 |
IL |
158320 |
Claims
1. A composite armor plate for absorbing and dissipating kinetic
energy from high-velocity projectiles, said plate comprising a
single internal layer of pellets which are bound and retained in
plate form, each of said pellets being characterized by a body
having a substantially regular geometric cross-sectional area and
first and second end faces, each of said end faces projecting from
said body and having an outwardly decreasing cross-sectional area
wherein the height of the end face disposed substantially opposite
to an outer impact receiving major surface of said plate is less
than 15% of the length of the diameter of the pellet body from
which it projects.
2. A composite armor plate according to claim 1, wherein the height
of the end face disposed substantially opposite to an outer impact
receiving major surface of said plate is less than the height of
the impact receiving end face.
3. A composite armor plate according to claim 1, wherein the end
face disposed substantially opposite to an outer impact receiving
major surface of said plate is spherical.
4. A composite armor plate according to claim 3, wherein said
end-face is convexly curved and wherein the ratio D/R between the
diameter D of the body of the pellet and the radius R of the
curvature of said convexly curved end face is between about 0.28:1
and 0.639:1.
5. A composite armor plate according to claim 1, wherein the end
face disposed substantially opposite to an outer impact receiving
major surface of said plate is in the form of an outwardly tapered
truncated cone.
6. A composite armor plate according to claim 1 whenever used as
ballistic protection for a rigid armor plate.
7. A composite armor plate according to claim 1, wherein a majority
of said pellets have at least one convexly-curved end face oriented
to substantially face in the direction of an outer impact receiving
major surface of said plate.
8. A composite armor plate according to claim 1, wherein said
pellets have at least one axis of at least 9 mm.
9. A composite armor plate according to claim 1, wherein said
pellets have at least one axis of at least 20 mm.
10. A composite armor plate according to claim 1, wherein each of
said pellets is formed of a ceramic material selected from the
group consisting of sintered oxide, nitrides, carbides and borides
of alumina, magnesium, zirconium, tungsten, molybdenum, titanium
and silica.
11. A composite armor plate according to claim 1, wherein each of
said pellets is formed of a material selected from the group
consisting of alumina, boron carbide, boron nitride, titanium
diboride, silicon carbide, silicon oxide, silicon nitride,
magnesium oxide, silicon aluminum oxynitride and mixtures
thereof.
12. A composite armor plate according to claim 1, wherein said
solidified material and said plate are elastic.
13. A composite armor plate according to claim 1, characterized in
that a channel is provided in a plurality of said pellets to reduce
the weight per area thereof.
14. A composite armor plate according to claim 13, wherein said
channel occupies a volume of up to 25% of said pellet.
15. A composite armor plate for absorbing and dissipating kinetic
energy from high-velocity projectiles, said plate comprising a
single internal layer of pellets which are bound and retained in
plate form by an elastic material, substantially internally within
said elastic material, such that the pellets are bound in a
plurality of spaced-apart rows and columns, said pellets being made
of ceramic material, and said pellets being substantially fully
embedded in the elastic material so that the pellets form an
internal layer, wherein said solidified material and said plate are
elastic, and wherein a majority of each of said pellets is
substantially in direct contact with six adjacent pellets in the
same layer to provide mutual lateral confinement therebetween, each
of said pellets being characterized by a body having a
substantially regular geometric cross-sectional area and first and
second end faces, each of said end faces projecting from said body
and having an outwardly decreasing cross-sectional area wherein the
height of the end face disposed substantially opposite to an outer
impact receiving major surface of said plate is less than 15% of
the length of the diameter of the pellet body from which it
projects.
16. A pellet for use in a composite armor plate for absorbing and
dissipating kinetic energy from high-velocity projectiles, said
pellet being made of a ceramic material and said pellet being
characterized by a substantially regular geometric cross-sectional
area, and first and second end faces, each of said end faces
projecting from said body and having an outwardly decreasing
cross-sectional area wherein the height of the end face disposed
substantially opposite to an outer impact receiving end face of
said pellet is less than 15% of the length of the diameter of the
pellet body from which it projects.
17. A pellet for use in a composite armor plate for absorbing and
dissipating kinetic energy from high-velocity projectiles according
to claim 13 wherein the height of the end face disposed
substantially opposite to an outer impact receiving end face of
said pellet is less than the height of the impact receiving end
face.
Description
[0001] The present invention relates to a ceramic body for
deployment in a composite armor panel, for absorbing and
dissipating kinetic energy from projectiles and to ballistic armor
panels incorporating the same. More particularly, the invention
relates to improved ceramic bodies for use in armored plates for
providing ballistic protection for light and heavy mobile equipment
and for vehicles against high-velocity, armor-piercing projectiles
or fragments and especially for use as add-on protection to rigid
armor plates such as the steel plates of armored vehicles.
[0002] The present specification is a continuation in part of U.S.
Ser. No. 10/937,205 filed on Sep. 8, 2004 and presently
pending.
[0003] The present invention is a modification of the inventions
described in U.S. Pat. Nos. 5,763,813; 5,972,819; 6,289,781;
6,112,635; 6,203,908; and 6,408,734 and in WO-A-9815796 the
relevant teachings of which are incorporated herein by
reference.
[0004] In U.S. Pat. No. 5,763,813 there is described and claimed a
composite armor material for absorbing and dissipating kinetic
energy from high velocity, armor-piercing projectiles, comprising a
panel consisting essentially of a single internal layer of high
density ceramic pellets said pellets having an Al.sub.2O.sub.3
content of at least 93% and a specific gravity of at least 2.5 and
retained in panel form by a solidified material which is elastic at
a temperature below 250.degree. C.; the majority of said pellets
each having a part of a major axis of a length of in the range of
about 3-12 mm, and being bound by said solidified material in
plurality of superposed rows, wherein a majority of each of said
pellets is in contact with at least 4 adjacent pellets, the weight
of said panel does not exceed 45 kg/m.sup.2.
[0005] In U.S. Pat. No. 6,112,635 there is described and claimed a
composite armor plate for absorbing and dissipating kinetic energy
from high velocity, armor-piercing projectiles, said plate
consisting essentially of a single internal layer of high density
ceramic pellets which are directly bound and retained in plate form
by a solidified material such that the pellets are bound in a
plurality of adjacent rows, wherein the pellets have an
Al.sub.2O.sub.3 content of at least 93% and a specific gravity of
at least 2.5, the majority of the pellets each have at least one
axis of at least 12 mm length said one axis of substantially all of
said pellets being in substantial parallel orientation with each
other and substantially perpendicular to an adjacent surface of
said plate and wherein a majority of each of said pellets is in
direct contact with 6 adjacent pellets, and said solidified
material and said plate are elastic.
[0006] In WO-A-9815796 corresponding to U.S. Pat. No. 5,972,819,
there is described and claimed a ceramic body for deployment in a
composite armor panel, said body being substantially cylindrical in
shape, with at least one convexly curved end face, wherein the
ratio D/R between the diameter D of said cylindrical body and the
radius R of curvature of said at least one convexly curved end face
is at least 0.64:1.
[0007] In U.S. Pat. No. 6,289,781 there is described and claimed a
composite armor plate for absorbing and dissipating kinetic energy
from high velocity projectiles, said plate comprising a single
internal layer of pellets which are directly bound and retained in
plate form by a solidified material such that the pellets are bound
in a plurality of adjacent rows, characterized in that the pellets
have a specific gravity of at least 2 and are made of a material
selected from the group consisting of glass, sintered refractory
material, ceramic material which does not contain aluminum oxide
and ceramic material having an aluminum oxide content of not more
than 80%, the majority of the pellets each have at least one axis
of at least 3 mm length and are bound by said solidified material
in said single internal layer of adjacent rows such that each of a
majority of said pellets is in direct contact with at least six
adjacent pellets in the same layer to provide mutual lateral
confinement therebetween, said pellets each have a substantially
regular geometric form and said solidified material and said plate
are elastic.
[0008] In U.S. Pat. No. 6,408,734 there is described and claimed a
composite armor plate for absorbing and dissipating kinetic energy
from high velocity, armor-piercing projectiles, as well as from
soft-nosed projectiles, said plate comprising a single internal
layer of high density ceramic pellets, characterized in that said
pellets are arranged in a single layer of adjacent rows and
columns, wherein a majority of each of said pellets is in direct
contact with at least four adjacent pellets and each of said
pellets are substantially cylindrical in shape with at least one
convexly-curved end face, further characterized in that spaces
formed between said adjacent cylindrical pellets are filled with a
material for preventing the flow of soft metal from impacting
projectiles through said spaces, said material being in the form of
a triangular insert having concave sides complimentary to the
convex curvature of the sides of three adjacent cylindrical
pellets, or being integrally formed as part of a special
interstices-filling pellet, said pellet being in the form of a six
sided star with concave sides complimentary to the convex curvature
of the sides of six adjacent cylindrical pellets, said pellets and
material being bound and retained in plate form by a solidified
material, wherein said solidified material and said plate material
are elastic.
[0009] The teachings of all of these specifications are
incorporated herein by reference.
[0010] As described and explained therein, an incoming projectile
may contact the pellet array in one of three ways: [0011] 1. Center
contact. The impact allows the full volume of the pellet to
participate in stopping the projectile, which cannot penetrate
without pulverizing the whole pellet, an energy-intensive task.
[0012] 2. Flank contact. The impact causes projectile yaw, thus
making projectile arrest easier, as a larger frontal area is
contacted, and not only the sharp nose of the projectile. The
projectile is deflected sideways and needs to form for itself a
large aperture to penetrate, thus allowing the armor to absorb the
projectile energy. [0013] 3. Valley contact. The projectile is
jammed, usually between the flanks of three pellets, all of which
participate in projectile arrest. The high side forces applied to
the pellets are resisted by the pellets adjacent thereto as held by
the substrate or plate, and penetration is prevented.
[0014] There are four main considerations concerning protective
armor panels. The first consideration is weight. Protective armor
for heavy but mobile military equipment, such as tanks and large
ships, is known. Such armor usually comprises a thick layer of
alloy steel, which is intended to provide protection against heavy
and explosive projectiles. However, reduction of weight of armor,
even in heavy equipment, is an advantage since it reduces the
strain on all the components of the vehicle. Furthermore, such
armor is quite unsuitable for light vehicles such as automobiles,
jeeps, light boats, or aircraft, whose performance is compromised
by steel panels having a thickness of more than a few millimeters,
since each millimeter of steel adds a weight factor of 7.8
kg/m.sup.2.
[0015] Armor for light vehicles is expected to prevent penetration
of bullets of any type, even when impacting at a speed in the range
of 700 to 1000 meters per second. However, due to weight
constraints it is difficult to protect light vehicles from high
caliber armor-piercing projectiles, e.g. of 12.7 and 14.5 mm and
above, since the weight of standard armor to withstand such
projectile is such as to impede the mobility and performance of
such vehicles.
[0016] A second consideration is cost. Overly complex armor
arrangements, particularly those depending entirely on composite
materials, can be responsible for a notable proportion of the total
vehicle cost, and can make its manufacture non-profitable.
[0017] A third consideration in armor design is compactness. A
thick armor panel, including air spaces between its various layers,
increases the target profile of the vehicle. In the case of
civilian retrofitted armored automobiles which are outfitted with
internal armor, there is simply no room for a thick panel in most
of the areas requiring protection.
[0018] A fourth consideration relates to ceramic plates used for
personal and light vehicle armor, which plates have been found to
be vulnerable to damage from mechanical impacts caused by rocks,
falls, etc.
[0019] Fairly recent examples of armor systems are described in
U.S. Pat. No. 4,836,084, disclosing an armor plate composite
including a supporting plate consisting of an open honeycomb
structure of aluminum; and U.S. Pat No. 4,868,040, disclosing an
antiballistic composite armor including a shock-absorbing layer.
Also of interest is U.S. Pat. No. 4,529,640, disclosing spaced
armor including a hexagonal honeycomb core member.
[0020] Other armor plate panels are disclosed in British Patents
1,081,464; 1,352,418; 2,272,272, and in U.S. Pat. No. 4,061,815
wherein the use of sintered refractory material, as well as the use
of ceramic materials, are described.
[0021] In the majority of the patents by the present inventor, the
preferred embodiments are pellets having a cylindrical body and at
least one convexly curved end face and the especially preferred
embodiment is that described in U.S. Pat. No. 5,972,819 wherein the
body is substantially cylindrical in shape with at least one
convexly curved end face, and preferably two identical convexly
curved end faces, wherein the ratio D/R between the diameter D of
said cylindrical body and the radius R of curvature of said
convexly curved end faces is at least 0.64:1.
[0022] It has now been found that when mounting composite armor
panels as add-on protection for the rigid steel armor of light and
heavy armored vehicles, the pellet itself is capable of damaging or
even penetrating said rigid steel armor backing.
[0023] With this state of the art and these considerations in mind,
there is now provided according to the present invention a
composite armor plate for absorbing and dissipating kinetic energy
from high-velocity projectiles, said plate comprising a single
internal layer of pellets which are bound and retained in plate
form, each of said pellets being characterized by a body having a
substantially regular geometric cross-sectional area and first and
second end faces, each of said end faces projecting from said body
and having an outwardly decreasing cross-sectional area wherein the
height of the end face disposed substantially opposite to an outer
impact receiving major surface of said plate is less than 15% of
the length of the diameter of the pellet body from which it
projects.
[0024] Preferably, the height of the end face disposed
substantially opposite to an outer impact receiving major surface
of said plate is less than the height of the impact receiving end
face.
[0025] In first preferred embodiments of the present invention, the
end face disposed substantially opposite to an outer impact
receiving major surface of said plate is spherical.
[0026] In these first preferred embodiments, especially preferred
are pellets wherein said end-face is convexly curved and wherein
the ratio D/R between the diameter D of the body of the pellet and
the radius R of the curvature of said convexly curved end face is
between about 0.28:1 and 0.639:1.
[0027] In further preferred embodiments of the present invention,
the end face disposed substantially opposite to an outer impact
receiving major surface of said plate is in the form of an
outwardly tapered truncated cone forming a chamfered end.
[0028] As stated, the composite armor plate and pellets of the
present invention are especially preferred whenever used as
ballistic protection for a rigid armor plate since it has been
found that they increase the area distribution of the initial
impact of the pellet as transferred by inertia from the impacting
projectile.
[0029] Thus the major difference between the plate and pellets of
the present invention and those of the prior plates and pellets in
this series is in the shape and size of the end face disposed
substantially opposite to the outer impact receiving major surface
of the plate however, nevertheless it is still preferred that a
majority of said pellets have at least one convexly-curved end face
oriented to substantially face in the direction of an outer impact
receiving major surface of said plate.
[0030] As stated, the present invention also provides a pellet for
use in a composite armor plate for absorbing and dissipating
kinetic energy from high-velocity projectiles, said pellet being
made of a ceramic material and said pellet being characterized by a
substantially regular geometric cross-sectional area, and first and
second end faces, each of said end faces projecting from said body
and having an outwardly decreasing cross-sectional area wherein the
height of the end face disposed substantially opposite to an outer
impact receiving end face of said pellet is less than 15% of the
length of the diameter of the pellet body from which it
projects.
[0031] In preferred embodiments of this aspect of the present
invention there is provided a pellet for use in a composite armor
plate for absorbing and dissipating kinetic energy from
high-velocity projectiles, wherein the height of the end face
disposed substantially opposite to an outer impact receiving end
face of said pellet is less than the height of the impact receiving
end face.
[0032] In the preferred embodiments of the present invention said
pellets have at least one axis of at least 9 mm and the present
invention is especially applicable and preferred for use with
plates incorporating pellets having at least one axis of at least
20 mm.
[0033] In yet further embodiments of the present invention a
channel is provided in a plurality of said pellets to reduce the
weight per area thereof.
[0034] In said further embodiments said channel preferably occupies
a volume of up to 25% of said pellet.
[0035] In especially preferred embodiments of the present
invention, there is now provided a composite armor plate for
absorbing and dissipating kinetic energy from high-velocity
projectiles, said plate comprising a single internal layer of
pellets which are bound and retained in plate form by an elastic
material, substantially internally within said elastic material,
such that the pellets are bound in a plurality of spaced-apart rows
and columns, said pellets being made of ceramic material, and said
pellets being substantially fully embedded in the elastic material
so that the pellets form an internal layer, wherein said solidified
material and said plate are elastic, and wherein a majority of each
of said pellets is substantially in direct contact with six
adjacent pellets in the same layer to provide mutual lateral
confinement therebetween, each of said pellets being characterized
by a body having a substantially regular geometric cross-sectional
area and first and second end faces, each of said end faces
projecting from said body and having an outwardly decreasing
cross-sectional area wherein the height of the end face disposed
substantially opposite to an outer impact receiving major surface
of said plate is less than 15% of the length of the diameter of the
pellet body from which it projects.
[0036] While the cylindrical pellets of this preferred embodiment
are defined as being substantially in direct contact with six
adjacent pellets, it is known that a ceramic body which has been
pressed, by it's nature, has an external surface area which is not
smooth and has lack of consistency in its diameter along the main
axis, and it is because of this that when casting the panel with
the solidified material, the casting materials such as resin,
molten alumina, epoxy, etc., seeps into all spaces between the
ceramic bodies such as between cylinders and spheres and the like,
including the very small space found between the walls of two or
more adjoining cylinders, forming a natural retaining substance in
which the ceramic bodies are confined. Thus even when the ceramic
bodies are closely packed, the casting material will at least
partially penetrate between any two bodies. This is due to the fact
that during the pressing process, the ceramic material is compacted
in the die and when the material is released from the die the
material has a tendency to try and spring back to a less compact
form. This generally occurs in the top part of the material so
pressed, which is the first part of the body released from the die.
Thus, in this case, there will be a small difference in the
diameter of the body along the vertical axis. Secondly, it is well
known that during the pressing process there are sometimes
differences in densification of the powder in different areas of
the ceramic body. When sintering the ceramic body, these small
differences will cause the body to shrink in accordance with the
different compressions found in various areas of the body,
resulting in another reason for a small lack of homogeneity in the
diameter along the vertical axis of the body. Thus there is rarely
a situation in which one ceramic body is perfectly in direct
contact with a second ceramic body in the panel along its entire
vertical surface, rather, the casting material will seep between
the two bodies, at least partially encasing each of said bodies,
thus creating at least a partial honey-comb sleeve, that at least
partially enwraps the ceramic body, and the term substantially in
direct contact, is intended to also denote this possibility.
[0037] Furthermore, when the casting material of the plate is a
liquefied solid material, if one were to x-ray the panel, one would
see that the panel shows a honey-combed shaped casting, which at
least partially encloses the ceramic bodies. Since this is the
case, it is possible also to first cast such a partial honey-combed
shape and then to place the special insert pellets and the other
pellets in the proper configuration therein.
[0038] Furthermore, because of the support this ceramic body
receives from the backing layers, one may distance the ceramic
cylinders or said ceramic bodies, one from another, until V50
penetration for 7.62 mm ammunition at muzzle velocity is
attained.
[0039] For standard ceramic bodies, such as ceramic cylinders, with
similar convex domes based on small radii, which are even somewhat
reminiscent of a ball, there are small contact points with the
backing material, and with adjacent bodies, and when impacted by a
projectile in any side of the cylinder, or ceramic body, the
cylinder or ceramic body may have a tendency to tumble or turn and
allow the projectile to lightly penetrate without breaking the
ceramic body because of the high structural strength of the ceramic
body. In contradistinction, when working with a ceramic body or
cylinder, according to the present invention, having first and
second end faces wherein each of said end faces projects from said
body and has an outwardly decreasing cross-sectional area wherein
the height of the end face disposed substantially opposite to an
outer impact receiving major surface of said plate is less than 15%
of the length of the diameter of the pellet body from which it
projects, said latter end face has a larger radius and surface area
which is in contact with the backing, and this property allows the
cylinders to spread the energy over a larger area and therefore the
body has a far less tendency to twist or turn or tumble upon said
projectile impact, which further allows for the ceramic cylinders
or ceramic bodies to be set further apart from one another. In
order to provide for homogeneity of distance between all of the
ceramic cylinders or bodies used in such a fashion, these bodies
can be wrapped or encapsulated by rings made from various materials
such as aluminum or any material with a low aerial density so long
as the rings made from these materials will maintain equal distance
between the ceramic bodies mentioned above.
[0040] In like fashion, it is possible to place the ceramic
cylinders or ceramic bodies into a honey-comb structure, which has
been previously fashioned, when the thickness of the walls of the
honey-comb will allow the cylinders or ceramic bodies to maintain
equal distance one from the other as mentioned above while
preferably allowing for valley contact between adjacent bodies as
discussed herein.
[0041] In the event that it is desirable to insure a situation in
which the ceramic cylinders or ceramic bodies are distanced one
from another and still retain their full ballistic resistance
capabilities one may add an "ear" or a pin-like protrusion to the
ceramic body which acts to sufficiently slow and erode the
penetrating projectile or fragment. By adding this pin-like
protrusion or ear to the ceramic cylinder or ceramic body, the
contact valley effect that has been described herein, is improved
in comparison to the contact-valley effect found in the absence of
such pin-like protrusions or ears. This is also the case when the
ceramic bodies or cylinders are not separated one from another by
any distance and are substantially at least partially in contact
with each other.
[0042] This pin-like protrusion or ear can be either a part of the
ceramic body or cylinder or can be a separate ceramic body onto
itself.
[0043] When the pin-like protrusion or ear is not a part of the
ceramic cylinder or body, but is, in itself, a separate entity, it
can be made of ballistic materials with a high hardness such as
ceramics or high hard metals or any other materials with a high
hardness which are wear resistant.
[0044] The pin can be roll shaped, ball shaped, pyramidal, or
prismatic or any shape that can resist and erode the impacting
projectile. Because of the fact that the ceramic body has already
defeated the impacting projectile the purpose of the pin is merely
to diminish the potential speed of the resulting fragments.
[0045] When it is desirable to insure equal distance between the
ceramic cylinders or ceramic bodies, these bodies can be wrapped or
encapsulated by rings made from various materials such as aluminum
or any material with a low aerial density as has been previously
mentioned and when this is done to ceramic cylinders or ceramic
bodies which are used in conjunction with the pin-like protrusions
or ears previously described the pin or ears both diminish the
impacting speed of the fragments or projectiles and also erode
them.
[0046] In like manner, the cylinders with pins or ears can be
placed in a pre-formed honeycomb as previously described.
[0047] Thus, the afore-described bodies can be united or bonded
inside any unifying material in a single layer. This uniting or
bonding material can be made from materials such as a thermoplastic
polymer, e.g., a polycarbonate, or can be made from a thermoset
plastic such as epoxy or polyurethane, or from aluminum, magnesium,
steel, etc.
[0048] The panel that is based on cylinders or ceramic bodies
bonded together inside a unifying or bonding material, is a
ballistic panel designed to resist projectile penetration. However,
when it is desirable to improve the ballistic tendency of said
panel against multi-impacting projectiles or against improvised
explosive device (IED) threats, it is possible to add materials
that will improve the panel's over-all resistance and ability to
defeat threats, such as Kevlar, Fiber Phenol, aluminum, titanium or
perforated steel, or any of them in any combination, or, in like
manner, to cast them in a box which has been previously
prefabricated in accordance with the desired structural
characteristics.
[0049] In like manner, it is also possible to add to the panel,
either frontally, behind the panel, or on any of its sides, or in
any combination, materials or a combination of materials, which
will improve the structural strength of the panel improving its
ability to stand against both multi-impact and IED threats.
[0050] The term "regular geometric" as used herein refers to forms
that are regular forms such as circles and ovals as well as forms
that repeat themselves including star shapes, polygonal
cross-sectional shapes and multiple repeating patterns of
alternating straight and curved segments characterized in that a
cut along said regular geometric cross-sectional area or
perpendicular thereto results in two surfaces which are
symmetrical.
[0051] The term "elasticity" as used herein relates to the fact
that the plates according to the present invention are bent when a
load is applied thereto however upon release of said load the plate
returns to its original shape without damage.
[0052] The armor plates described in EP-A-0843149 and European
Patent Application 98301769.0 are made using ceramic pellets made
substantially entirely of aluminum oxide. In WO-A-9815796 the
ceramic bodies are of substantially cylindrical shape having at
least one convexly-curved end-face, and are preferably made of
aluminum oxide.
[0053] In WO 99/60327 it was described that the improved properties
of the plates described in the earlier patent applications of this
series is as much a function of the configuration of the pellets,
which are of regular geometric form with at least one
convexly-curved end face (for example, the pellets may be spherical
or ovoidal, or of regular geometric cross-section, such as
hexagonal, with at least one convexly-curved end face), said panels
and their arrangement as a single internal layer of pellets bound
by an elastic solidified material, wherein each of a majority of
said pellets is in direct contact with at least four adjacent
pellets and said curved end face of each pellet is oriented to
substantially face in the direction of an outer impact-receiving
major surface of the plate. As a result, said specification teaches
that composite armor plates superior to those available in the
prior art can be manufactured using pellets made of sintered
refractory materials or ceramic materials having a specific gravity
below that of aluminum oxide, e.g., boron carbide with a specific
gravity of 2.45, silicon carbide with a specific gravity of 3.2 and
silicon aluminum oxynitride with a specific gravity of about
3.2.
[0054] Thus, it was described in said publication that sintered
oxides, nitrides, carbides and borides of magnesium, zirconium,
tungsten, molybdenum, titanium and silica can be used and
especially preferred for use in said publication and also in the
present invention the ceramic bodies utilized herein are formed of
a ceramic material selected from the group consisting of sintered
oxide, nitrides, carbides and borides of alumina, magnesium,
zirconium, tungsten, molybdenum, titanium and silica.
[0055] All of these features are incorporated herein as preferred
embodiments of the present invention.
[0056] More particularly, the present invention relates to a
ceramic body as defined for absorbing and dissipating kinetic
energy from high velocity armor piercing projectiles, wherein said
body is made of a material selected from the group consisting of
alumina, boron carbide, boron nitride, titanium diboride, silicon
carbide, silicon oxide, silicon nitride, magnesium oxide, silicon
aluminum oxynitride and mixtures thereof.
[0057] In preferred embodiments of the present invention said
pellets each have a major axis and said pellets are arranged with
their major axes substantially parallel to each other and oriented
substantially perpendicularly relative to said outer
impact-receiving major surface of said panel.
[0058] Thus, in preferred embodiments of the present invention
there is provided a composite armor plate as herein defined,
wherein a majority of said pellets have at least one
convexly-curved end face oriented to substantially face in the
direction of an outer impact receiving major surface of said
plate.
[0059] The solidified material can be any suitable material, such
as aluminum, a thermoplastic polymer such as polycarbonate, or a
thermoset plastic such as epoxy or polyurethane.
[0060] When aluminum is used as said solidified material an x-ray
of the plate shows the formation of a honeycomb structure around
the pellets.
[0061] In French Patent 2,711,782, there is described a steel panel
reinforced with ceramic materials; however said panel does not have
the ability to deflect armor-piercing projectiles unless a
thickness of about 8-9 mm of steel is used, which adds undesirable
excessive weight to the panel and further backing is also necessary
thereby further increasing the weight thereof.
[0062] The composite armor plate according to the present invention
can be used in conjunction with and as an addition to the standard
steel plates provided on armored vehicles or as add on armor for
armored vehicles having aluminum or titanium containing rigid
surfaces, as well as in conjunction with the laminated armor
described and claimed in U.S. Pat. No. 6,497,966 the teachings of
which are incorporated herein by reference.
[0063] According to a further aspect of the invention, there is
provided a multi-layered armor panel, comprising an outer,
impact-receiving layer formed by a composite armor plate as
hereinbefore defined for deforming and shattering an impacting high
velocity projectile; and an inner layer adjacent to said outer
layer and, comprising a ballistic material for absorbing the
remaining kinetic energy from said fragments. Said ballistic
material will be chosen according to cost and weight considerations
and can be made of any suitable material such as Dyneema, Kevlar,
aluminum, steel, titanium, or S2, or any combination thereof.
[0064] As described, e.g., in U.S. Pat. No. 5,361,678, composite
armor plate comprising a mass of spherical ceramic balls
distributed in an aluminum alloy matrix is known in the prior art.
However, such prior art composite armor plate suffers from one or
more serious disadvantages, making it difficult to manufacture and
less than entirely suitable for the purpose of defeating metal
projectiles. More particularly, in the armor plate described in
said patent, the ceramic balls are coated with a binder material
containing ceramic particles, the coating having a thickness of
between 0.76 and 1.5 mm and being provided to help protect the
ceramic cores from damage due to thermal shock when pouring the
molten matrix material during manufacture of the plate. However,
the coating serves to separate the harder ceramic cores of the
balls from each other, and will act to dampen the moment of energy
which is transferred and hence shared between the balls in response
to an impact from a bullet or other projectile. Because of this and
also because the material of the coating is inherently less hard
than that of the ceramic cores, the stopping power of a plate
constructed as described in said patent is not as good, weight for
weight, as that of a plate in accordance with the present
invention.
[0065] U.S. Pat. No. 3,705,558 discloses a lightweight armor plate
comprising a layer of ceramic balls. The ceramic balls are in
contact with each other and leave small gaps for entry of molten
metal. In one embodiment, the ceramic balls are encased in a
stainless steel wire screen; and in another embodiment, the
composite armor is manufactured by adhering nickel-coated alumina
spheres to an aluminum alloy plate by means of a polysulfide
adhesive. A composite armor plate as described in this patent is
difficult to manufacture because the ceramic spheres may be damaged
by thermal shock arising from molten metal contact. The ceramic
spheres are also sometimes displaced during casting of molten metal
into interstices between the spheres.
[0066] In order to minimize such displacement, U.S. Pat. Nos.
4,534,266 and 4,945,814 propose a network of interlinked metal
shells to encase ceramic inserts during casting of molten metal.
After the metal solidifies, the metal shells are incorporated into
the composite armor. It has been determined, however, that such a
network of interlinked metal shells substantially increases the
overall weight of the armored panel and decreases the stopping
power thereof.
[0067] It is further to be noted that U.S. Pat. No. 3,705,558
suggests and teaches an array of ceramic balls disposed in
contacting pyramidal relationship, which arrangement also
substantially increases the overall weight of the armored panel and
decreases the stopping power thereof, due to a billiard-like effect
upon impact.
[0068] As will be realized, when preparing the composite armor
plate of the present invention, said pellets do not necessarily
have to be completely covered on both sides by said solidified
material, and the term internal layer as used herein is intended to
denote that the pellets are either completely or almost completely
covered by said solidified material, wherein outer face surfaces of
the plate are formed from the solidified material, the plate having
an outer impact receiving face, at which face each pellet is either
covered by the solidified material, touches said solidified
material which forms surfaces of said outer impact receiving face
or, not being completely covered by said solidified material which
constitutes surfaces of said outer impact receiving face, bulges
therefrom, the solidified material and hence the plate being
elastic.
[0069] In U.S. Ser. No. 09/924,745 there is described and claimed a
composite armor plate for absorbing and dissipating kinetic energy
from high velocity projectiles, said plate comprising a single
internal layer of pellets which are directly bound and retained in
plate form by a solidified material such that the pellets are bound
in a plurality of adjacent rows, said pellets having a specific
gravity of at least 2 and being made of a material selected from
the group consisting of glass, sintered refractory material and
ceramic material, the majority of the pellets each having at least
one axis of at least 3 mm length and being bound by said solidified
material in said single internal layer of adjacent rows such that
each of a majority of said pellets is in direct contact with six
adjacent pellets in the same layer to provide mutual lateral
confinement therebetween, said pellets each having a substantially
regular geometric form, wherein said solidified material and said
plate are elastic, characterized in that a channel is provided in
each of a plurality of said pellets, substantially opposite to an
outer impact-receiving major surface of said plate, thereby
reducing the weight per area of each of said pellets.
[0070] In preferred embodiments described therein each of said
channels occupies a volume of up to 25% within its respective
pellet.
[0071] Said channels can be bored into preformed pellets or the
pellets themselves can be pressed with said channel already
incorporated therein.
[0072] The teachings of said specification are also incorporated
herein by reference.
[0073] Thus, in preferred embodiments of the present invention a
channel is provided in the pellets of the armor of the present
invention to further reduce the weight per area thereof and
preferably said channel occupies a volume of up to 25% of said
body.
[0074] In accordance with the present invention said channels are
preferably of a shape selected from the group consisting of
cylindrical, pyramidal, hemispherical and quadratic, hexagonal
prism and combinations thereof.
[0075] As is known, there exists a ballistic effect known in the
art in which a projectile striking a cylinder at an angle has a
tendency to move this cylinder out of alignment causing a
theoretical possibility that a second shot would have more
penetration effect on a panel.
[0076] As will be realized, since material is removed from the
pellets of the present invention their weight is decreased, as is
the overall weight of the entire composite armor plate from which
they are formed, thereby providing the unexpected improvement of
reduced weight of protective armor panels without loss of stopping
power.
[0077] The invention will now be described in connection with
certain preferred embodiments with reference to the following
illustrative figures so that it may be more fully understood.
[0078] With reference now to the figures in detail, it is stressed
that the particulars shown are by way of example and for purposes
of illustrative discussion of the preferred embodiments of the
present invention only, and are presented in the cause of providing
what is believed to be the most useful and readily understood
description of the principles and conceptual aspects of the
invention. In this regard, no attempt is made to show structural
details of the invention in more detail than is necessary for a
fundamental understanding of the invention, the description taken
with the drawings making apparent to those skilled in the art how
the several forms of the invention may be embodied in practice.
[0079] In the drawings:
[0080] FIG. 1 is an elevational view of a first preferred pellet
according to the present invention;
[0081] FIG. 2 is an elevational view of a second preferred pellet
according to the present invention;
[0082] FIG. 3 is an elevational view of a third preferred pellet
according to the present invention; and
[0083] FIG. 4 is an elevational view of a fourth preferred pellet
according to the present invention.
[0084] Referring to FIG. 1 there is seen an elevational view of a
preferred pellet 2 according to the present invention having a
substantially cylindrical body 4 and two convexly curved end faces
6 and 8. As indicated in the drawing, end face 6 which is designed
to serve as the outer impact receiving end face of the pellet 2 has
a radius of curvature of 17 mm as indicated by the letter R and the
cylinder has a diameter of 28 mm. In contradistinction the end face
8 designed to be disposed substantially opposite to the outer
impact receiving end face 6 has a spherical surface with a radius
of curvature of 100 mm. Thus as will be realized, in this
embodiment, the ratio D/R between the diameter of the body of the
pellet and the radius R of the curvature of said convexly curved
end face 8 is 0.28:1.
[0085] Referring to FIG. 2 there is seen an elevational view of a
further preferred pellet 20 according to the present invention
having a substantially cylindrical body 24 and two convexly curved
end faces 26 and 28. As indicated in the drawing, end face 26 which
is designed to serve as the outer impact receiving end face of the
pellet 20 has a radius of curvature of 17 mm as indicated by the
letter R and the cylinder has a diameter of 28 mm. In
contradistinction the end face 28 designed to be disposed
substantially opposite to the outer impact receiving end face 26
has a spherical surface with a radius of curvature of 44 mm. Thus
as will be realized, in this embodiment, the ratio D/R between the
diameter of the body of the pellet and the radius R of the
curvature of said convexly curved end face 28 is 0.636:1.
[0086] Referring to FIG. 3 there is seen an elevational view of yet
a further preferred pellet 30 according to the present invention
having a substantially cylindrical body 34 with one convexly curved
end face 36 and a further end face 38 disposed substantially
opposite to the outer impact receiving end face 36 wherein said end
face 38 is in the form of an outwardly tapered truncated cone. As
with the embodiments discussed with reference to FIGS. 1 and 2, end
face 36 which is designed to serve as the outer impact receiving
end face of the pellet 30 has a radius of curvature of 17 mm as
indicated by the letter R and the cylinder has a diameter of 28 mm.
In contradistinction, the end face 38 designed to be disposed
substantially opposite to the outer impact receiving end face 36 is
in the form of a chamfer with a height (h) of 2 mm and wherein the
angle of the outwardly tapered truncated cone vis a vis the
cylindrical body is 45.degree.. Thus as will be realized, in this
embodiment, the height (h) of the end face 38 is less than 15% of
the length of the diameter of the pellet body from which it
projects and in fact is less than 10% of the length of the diameter
of the pellet body.
[0087] Referring now to FIG. 4 there is seen a variation of the
pellet 30 as described with reference to FIG. 3 and similar numbers
have been used to describe similar parts. Thus as seen, said
pellet, 30' is formed of a cylindrical body 34 with one convexly
curved end face 36 and a further end face 38 disposed substantially
opposite to the outer impact receiving end face 36 wherein said end
face 38 is in the form of an outwardly tapered truncated cone. As
with the embodiments discussed with reference to FIGS. 1 and 2, end
face 36 which is designed to serve as the outer impact receiving
end face of the pellet 30' has a radius of curvature of 17 mm as
indicated by the letter R and the cylinder has a diameter of 28 mm.
In contradistinction the end face 38 designed to be disposed
substantially opposite to the outer impact receiving end face 36 is
in the form of a chamfer with a height of 2 mm and wherein the
angle of the outwardly tapered truncated cone vis a vis the
cylindrical body is 45.degree.. In addition said pellet 30' is
provided with a channel 40 substantially opposite to the outer
impact-receiving end face 36 of said pellet, thereby reducing the
weight per area of said pellet. In the embodiment shown, said
channel has a diameter of 15 mm.
[0088] The pellets 2, 20 and 30' are all formed of a ceramic
material. Preferred ceramics are sintered oxide, nitrides, carbides
and borides of alumina, magnesium, zirconium, tungsten, molybdenum,
titanium and silica.
[0089] Preferred materials are typically alumina, boron carbide,
boron nitride, titanium diboride, silicon carbide, silicon oxide,
silicon nitride, magnesium oxide, silicon aluminum oxynitride and
mixtures thereof.
[0090] While not shown, the plates of the present invention or at
least the outer surface thereof can be furthered covered by a thin
layer of kevlar, fiberglass, or even aluminum for protection and
for concealing the structure thereof.
[0091] It will be evident to those skilled in the art that the
invention is not limited to the details of the foregoing
illustrative embodiments and that the present invention may be
embodied in other specific forms without departing from the spirit
or essential attributes thereof. The present embodiments are
therefore to be considered in all respects as illustrative and not
restrictive, the scope of the invention being indicated by the
appended claims rather than by the foregoing description, and all
changes which come within the meaning and range of equivalency of
the claims are therefore intended to be embraced therein.
* * * * *