U.S. patent application number 11/290451 was filed with the patent office on 2006-09-28 for perforated armor plates.
Invention is credited to Yoav Hirschberg, Mosche Ravid.
Application Number | 20060213360 11/290451 |
Document ID | / |
Family ID | 36587155 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060213360 |
Kind Code |
A1 |
Ravid; Mosche ; et
al. |
September 28, 2006 |
Perforated armor plates
Abstract
A system of armor plates is adapted for protection of a
structure against projectiles B and S of two characteristic
calibers D.sub.B and D.sub.S, D.sub.B>D.sub.S. The system
compres a main armor plate and an auxiliary plate mounted in front
of the main armor plate at a distance therefrom. The auxiliary
plate comprises a plate made of ballistic material and perforated
with through holes of characteristic diameter D, 1.2
D.sub.B>D>1.2 D.sub.S. At least one hard-material body of
diameter D.sub.H is disposed in each of the holes, such that the
auxiliary plate provides at least destabilization of impacting
projectiles S capable of free passage through an unobstructed hole
of diameter D.
Inventors: |
Ravid; Mosche; (Hod
Hasharon, IL) ; Hirschberg; Yoav; (M.P. Merom
Hagalil, IL) |
Correspondence
Address: |
NATH & ASSOCIATES, PLLC;Sixth Floor
1030 15th Street, N.W.
Washington
DC
20005
US
|
Family ID: |
36587155 |
Appl. No.: |
11/290451 |
Filed: |
December 1, 2005 |
Current U.S.
Class: |
89/36.01 |
Current CPC
Class: |
F41H 5/023 20130101;
F41H 5/0492 20130101; F41H 5/013 20130101; F41H 5/0414
20130101 |
Class at
Publication: |
089/036.01 |
International
Class: |
F41H 5/00 20060101
F41H005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 23, 2005 |
IL |
167615 |
Claims
1. A system of armor plates for protection of a structure against
projectiles B and S of two characteristic calibers D.sub.B and
D.sub.S, D.sub.B>D.sub.S, the system comprising a main armor
plate and an auxiliary plate mounted in front of said main armor
plate at a distance (stand-off) therefrom, wherein said auxiliary
plate comprises a perforated plate made of ballistic material and
perforated with through holes of characteristic diameter D, 1.2
D.sub.B>D>1.2 D.sub.S, and at least one hard-material body
disposed in each of said holes, such that said auxiliary plate
provides at least destabilization of impacting projectiles S
capable of free passage through an unobstructed hole of diameter
D.
2. The system of claim 1, wherein said body has diameter D.sub.H
which is not less than D-D.sub.S.
3. The system of claim 1, wherein said auxiliary armor plate is
connected to said main armor plate by a plurality of metallic bolts
or pins or brackets.
4. The system of claim 1, wherein the space between said auxiliary
armor plate and said main armor plate is free.
5. The system of claim 1, wherein the space between said auxiliary
armor plate and said main armor plate is at least partially filled
with a non-ballistic material.
6. The system of claim 5, wherein said non-ballistic material is a
honeycomb structure.
7. The system of claim 1 constructed of panels comprising said main
armor plate and said auxiliary armor plate fixed at said stand-off
therefrom, said panels being adapted for mounting on said
structure.
8. An armor panel for constructing the system of claim 1, said
panel comprising said main armor plate and said auxiliary armor
plate fixed at said distance L therefrom, said panel being adapted
for mounting on said structure.
9. An auxiliary armor plate for use in a system of armor plates for
protection of a structure against projectiles B and S of two
characteristic calibers D.sub.B and D.sub.S, D.sub.B>D.sub.S,
the system further comprising a main armor plate, said auxiliary
armor plate being adapted for mounting in front of said main armor
plate at a distance therefrom, wherein said auxiliary plate
comprises a perforated plate made of ballistic material and
perforated with through holes of characteristic diameter D, 1.2
D.sub.B>D>1.2 D.sub.S, and at least one hard-material body
disposed in each of said holes, so that said auxiliary plate
provides at least destabilization of impacting projectiles S
capable of free passage through an unobstructed hole of diameter
D.
10. The auxiliary plate of claim 9, wherein said body has a
diameter D.sub.H which is not less than D-D.sub.S.
11. The auxiliary plate of claim 9, wherein said carrying plate is
made of ballistic steel.
12. The auxiliary plate of claim 9, wherein said holes are disposed
with center-to-center spacing from 1.2 D to 1.9 D.
13. The auxiliary plate of claim 12, wherein said holes are
disposed in a regular array.
14. The auxiliary plate of claim 10, wherein said hard-material
bodies are made of ceramics.
15. The auxiliary plate of claim 10, wherein said hard-material
bodies are fixed in said holes by plastic resin or aluminum.
16. The auxiliary plate of claim 9, further comprising at least one
front and/or rear layer of material bonded thereto so as to fix the
hard-material bodies in said holes.
17. The auxiliary plate of claim 16, wherein said at least one
layer is one or more of the following: fiberglass, aramid fabric,
metallic sheet, carbon or other fibers in hard matrix.
18. An add-on armor kit comprising the auxiliary armor plate of
claim 9 and an instruction for use thereof in said system of armor
plates.
19. The add-on armor kit of claim 18, further comprising means for
mounting said auxiliary armor plate on said structure.
Description
FIELD OF THE INVENTION
[0001] This invention relates to multi-layer ballistic armor and,
particularly, to armor plates suitable for use as add-on (exterior)
armor for military vehicles.
BACKGROUND OF THE INVENTION
[0002] Perforated or slit armor plates are in use for many years in
armor systems where they are installed at some stand-off distance
from the vehicle's basic armor. The use of those plates is mainly
to effectively break an incoming projectile or at least to divert
it from its incident trajectory and thus substantially reduce its
residual penetration capability through the basic armor. The total
weight of such armor system is considerably less than the weight of
a basic armor with the same antiballistic capability. Usually the
holes or slits are designed to interact with the characteristic
diameter of the threat (projectile caliber), and the performance
effectiveness of such armor under impact is dominated by the plate
material and thickness.
[0003] U.S. Pat. No. 5,014,593 discloses perforated plate armor
including outer and inner perforated steel plates and which have
associated patterns of holes. The plates are spaced with respect to
each other and with respect to the object to be protected. The
patterns of holes of the perforated steel plates are offset with
respect to each other to prevent straight line penetration. An
inner backing plate is provided to stop any particles that might
penetrate both perforated steel plates. Fillers and connectors
space the outer and inner perforated steel plates and the backing
plate with respect to each other.
[0004] U.S. Pat. No. 5,221,807 discloses a ballistic armor with
front and rear layers, which are spaced from each other by a
spacing layer. The front layer is made of ceramic material formed
with blind holes, and it is designed to score impacting projectiles
before they strike the rear layer, which functions as a main armor
layer.
[0005] EP 0 699 887 describes an antiballistic structure comprising
a front stand-off panel including an elastically deformable
laminate matrix and a plurality of rigid elements supported
therein. The rigid elements are means for absorbing the energy of
the incident projectiles and for destabilizing them. The front
panel is mounted on a deformable separator layer which is fixed on
a main armor plate.
[0006] U.S. Pat. No. 4,398,446 discloses add-on armor arrangements
designed for the attachment to a side wall of a military vehicle to
provide different levels of ballistic protection. The difference in
the arrangements is mainly in the number of armor layers and their
location relative to the vehicle's side wall. In particular, in
some arrangements where only one armor layer is used, it is mounted
either directly or close to the vehicle's side wall or at a
location spaced therefrom by spacers. In the arrangements where two
armor layers are used, one of them is mounted directly or close to
the vehicle's side wall while the other is mounted at a location
spaced therefrom. In all the cases, each armor layer consists of
tiles whose edges abut each other to define a substantially
uninterrupted armor surface.
[0007] EP 1 128 154 describes a ballistic armor panel for attaching
to an object, the panel comprising a carrying board made of a hard
material such as steel and formed with a plurality of adjoining
through-going holes. Each hole accommodates a body made of a hard
material. The panel is mounted face to face with the protected
object.
SUMMARY OF THE INVENTION
[0008] In this application, some terms will be used as follows:
[0009] Destabilization (of a projectile) is loss of stable
orientation of the projectile axis along the flight trajectory as a
result of a non symmetrical impact with a layer of material. The
destabilization is measured by the yaw angle between the projectile
longitudinal axis and the direction of the flight trajectory. The
yaw angle increases the stopping power effectiveness of the armor
system especially when the yaw angle exceeds 5.degree..
[0010] Characteristic diameter (of a projectile or an opening) is
just the diameter, if the projectile or the opening is circular,
or
[0011] diameter of the largest inscribed circle, in case of a
non-circular opening; and
[0012] diameter of the smallest described circle, in the case of a
projectile with non-circular cross-section (shrapnel or
fragment);
[0013] Ballistic material is a hard material capable of penetration
resistance.
[0014] Main armor plate is an armor plate mounted closest to the
structure to be protected or resident therein. A wall of the
structure may be also a main armor plate or part thereof.
[0015] In accordance with one aspect of the present invention,
there is provided a system of armor plates for protection of a
structure such as a vehicle against projectiles B and S of two
characteristic calibers D.sub.B and D.sub.S, D.sub.B being larger
than D.sub.S. The system comprises a main armor plate and an
auxiliary armor plate mounted in front of the main armor plate at a
distance L therefrom. The auxiliary plate is perforated with
through holes of characteristic diameter D, D being larger than
D.sub.S up to about 1.2 D.sub.B. At least one hard-material body is
fixed in each of the holes, so as to provide at least
destabilization of impacting projectiles S or B capable of free
passage through an unobstructed hole of diameter D when striking
close to the hole center.
[0016] The space between the auxiliary armor plate and the main
armor plate may be free or at least partially filled with a
non-ballistic material, for example a honeycomb structure.
[0017] The auxiliary armor plate may be connected to the main armor
plate by a plurality of metallic bolts, pins or brackets.
[0018] The system may be constructed of panels comprising the main
armor plate and the auxiliary armor plate fixed at the distance L
therefrom, the panels being adapted for mounting on the
structure.
[0019] According to another aspect of the present invention, there
is provided an auxiliary armor plate for use in the above system of
armor plates, which auxiliary plate may be made of ballistic
steel.
[0020] The holes in the auxiliary plate are preferably disposed
with center to center spacing from 1.2 D to 1.9 D, preferably in a
regular array.
[0021] The hard-material bodies may be made of ceramics and may be
fixed in the holes by resin or metal.
[0022] The auxiliary plate may further comprise at least one front
and/or rear layer of material bonded thereto so as to fix the
hard-material bodies in the holes. The material may be fiberglass,
aramid fabric, metallic sheet or other fiber fabric in resin
matrix.
[0023] According to further aspect of the present invention, there
is provided an add-on armor kit comprising the above auxiliary
armor plate, an instruction for use thereof in a system of armor
plates, and optionally, means for mounting the auxiliary armor
plate on the protected structure.
[0024] The invention may be applied to various types of military
vehicles and may provide combined ballistic protection against
projectiles of different diameters ranging, for example from 7.62
mm, 0.5'' (12.7 mm), to 14.5 mm or even to 20 mm.
[0025] The armor having the main and auxiliary plates according to
the present invention may have a lighter weight than the weight it
would need to have in order to provide the same level of ballistic
protection, if the armor consisted only of one plate or if the
auxiliary plate had only through openings. Moreover, when used as
an add-on armor on a vehicle's basic structure, the auxiliary armor
plate of the present invention may allow a smaller distance to the
basic structure, than the distance it would need to have for the
same level of ballistic protection, with single plate armor of the
same weight (perforated or not).
[0026] The above may be partially explained by the combined effect
of:
[0027] the auxiliary plate with holes and hard bodies, which may
cause a projectile of wide caliber range, when penetrating and
impact the hard bodies of said auxiliary plate, to be deflected and
to further be initially shattered or at least destabilized; and
[0028] the spacing between the auxiliary and the main plates, which
allows the deflected projectile trajectory or destabilized
projectile attitude to further deviate from a normal impact on the
main plate, or allows the projectile's parts to be more separated
in space between their impact on the main plate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to understand the invention and to see how it may
be carried out in practice, an embodiment will now be described, by
way of non-limiting example only, with reference to the
accompanying drawings, in which:
[0030] FIG. 1 is a schematic perspective view of a ballistic armor
in accordance with an embodiment of the present invention; and
[0031] FIG. 2 is a cross-sectional view of the armor shown in FIG.
1.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0032] An armor system 10 schematically shown in FIGS. 1 and 2 is
an example of ballistic armor of the present invention designed for
ballistic protection of a basic structure, e.g. side wall 12 of a
vehicle, against two kinds of ballistic threats, for example, large
caliber bullets B and smaller caliber bullets S.
[0033] The armor 10 comprises a main armor plate 14 and an
auxiliary armor plate 16 located in front of the main armor plate
14. The plates 14 and 16 are attached to the side wall 12 by
attachment means such as bolts 18 as shown in FIG. 1.
Alternatively, the main armor plate 14 may be attached to the side
wall 12 by one attachment means, and the auxiliary plate 16 may be
attached to the main plate 14 or to the side wall by another
attachment means. The attachment means are designed to keep the
plates at a predetermined fixed distance (stand-off) from each
other.
[0034] The main armor plate 14 is designed to stop alone, or
together with the side wall 12 but without the auxiliary plate 16,
projectiles of relatively small diameter D.sub.S and penetration
capability (lower level threats) such as 7.62 mm small arm bullets.
The main plate may be a composite armor plate, for example
comprising front layer 20 and a rear, backing layer 22 bonded to
the front layer. The front layer 20 may comprise cylindrical
pellets made of ceramics, for example alumina, held by synthetic
resin. The rear layer 22 may be made of aluminum sheet, fiberglass,
aramid fiber material such as Kevlar.TM., another fabric in resin,
or a combination thereof. It should be understood that the side
wall may be integral with the main armor plate or may be considered
a main armor plate by itself, as a component of the armor system
described herein.
[0035] The auxiliary plate 16 comprises a perforated plate which
may be made of steel, titanium or aluminum and their alloys, or of
carbon fibers and the likes in hard resin matrix. The perforated
plate is formed with through holes 19 of diameter D, spaced from
each other by a distance and arranged in a regular pattern.
[0036] The perforated plate with the holes 19 may be designed to
deflect and shatter or at least destabilize by itself projectiles
with relatively large diameter D.sub.B which cannot be stopped by
the main plate 14 alone or together with the side wall 12. For
example, such projectiles may be 0.5'' to 14.5 mm machine-gun armor
piercing bullets. The diameter D of the holes in this case is
smaller than D.sub.B but large enough to be felt by a projectile of
diameter D.sub.B, when impacting the hole. The range of D then may
be between D.sub.S and D.sub.B, preferably 1.1
D.sub.S<D.ltoreq.0.9 D.sub.B. The total area of the holes 19 is
preferably between 40% and 50% of the area of the perforated plate.
For example, for bullets of 0.5'' or 14.5 mm caliber, holes of
diameter D=11 mm may be used (in 8 mm thick plate), arranged in
staggered rows, with centers disposed at 16 mm from each other.
[0037] In operation, a projectile B impacts the perforated plate
and, while penetrating the plate, is deflected (its path is
deviated from the normal flight direction thereof) and initially
shattered or at least destabilized. The destabilized and deflected
projectile or parts thereof, then impact the front layer 20 of the
main plate 14, which further shatters the projectile or its parts
into small fragments. The backing layer 22 absorbs and dissipates
kinetic energy of the fragments on the protected side wall 12, at
which the projectile is finally stopped.
[0038] However, the perforated plate alone, as described above, may
be pierced by low caliber threats, such as the bullet of diameter
D.sub.S, passing through the holes 19 when D>D.sub.S without any
influence to their trajectory. For example, a 7.62 mm bullet may
pass easily through 11 mm dia holes. Although the main armor plate
14 will be usually capable to stop such low-level threat, sometimes
a small-caliber threat may be an overmatch to the main armor plate.
Such threat may be special armor-piercing munitions with WC
(Tungsten Carbide) core, such as 7.62.times.51 mm API(WC)FFV,
NAMMO, etc.
[0039] To avoid such situation, the present invention provides hard
bodies of characteristic diameter D.sub.H such as ceramic pellets
28 which are placed in the holes 19, as shown in FIG. 2, to augment
the perforated plate and obtain the auxiliary plate 16. The bodies
may be bonded in the holes, and the auxiliary plate may be covered
at one or both sides by a thin layer of laminated fabrics 30 such
as fiberglass, aramid, carbon or other fibers in hard resin etc.
and/or metallic sheet such as aluminum sheet.
[0040] With such arrangement, the low-caliber threat S will impact
either the auxiliary plate 16 or one of hard bodies 28 and will be
shattered, or at least destabilized, losing great deal of its
penetrating capability. The operation of the armor 10 against the
large-caliber projectile B will be at least the same as the
perforated plate without the hard bodies, or even may have improved
performance.
[0041] Although this solution will raise somewhat the areal density
(weight) of the auxiliary plate of given thickness, it will enhance
its performance and efficiency. The eventual effect will be that
the overall weight may be reduced, for example 8 mm thick steel
auxiliary plate with ceramic bodies will be equivalent to 10 mm
thick steel perforated plate that still cannot affect all
low-caliber special threats (for example, WC core). Moreover, the
inventors have found that adding fixed hard bodies in the holes
allows making the holes larger without losing the antiballistic
effect against the higher-caliber threat B. The diameter D of the
hole may be made as large as about 1.2 D.sub.B. Those projectiles B
that hit close to the hole center are shattered by the impact into
the hard body. It will be appreciated that, especially with larger
holes, the diameter D.sub.H of the hard bodies is preferably not
less than the difference between D and D.sub.S, i.e. not less than
D-D.sub.S in order to avoid penetration of low-caliber threat S if
the hard body is bonded off-center. Thus, the usage of larger holes
allows further reducing the weight of the auxiliary plate,
especially if made of steel, as the ceramic bodies have lower
specific weight than steel.
[0042] The perforated plate for the auxiliary plate 16 may be made
of metallic or non metallic materials such as ballistic steel of
various grades, titanium, aluminum alloys, hard fibrous material
plates or laminates etc, by drilling, milling, punching, laser or
water jet cut, etc.
[0043] The armor 10 may be produced as a module with the auxiliary
plate 16 fixedly attached to the main plate. The module may be
provided with means for mounting on the vehicle side wall 12, which
may be protected by a number of such modules. Alternatively, the
auxiliary plate may be produced separately as add-on plate and
mounted at a vehicle manufacturer facility or at an
armor-specialized workshop. Also, the auxiliary plate may be
offered in a kit with means for mounting and instructions for
mounting on a vehicle with given basic armor and required ballistic
protection level.
[0044] Although a description of specific embodiments has been
presented, it is contemplated that various changes could be made
without deviating from the scope of the present invention as
defined in the following claims. For example, the holes in the
auxiliary plate may be of non-circular form but polygonal, elliptic
or extended like slits. The space between the two plates may be
empty or filled by a spacing layer of non-ballistic material such
as wood, plastic or light metal layer which may be formed as porous
foam or honeycomb, etc.
* * * * *