U.S. patent application number 10/938199 was filed with the patent office on 2005-06-16 for wall breaching apparatus and method.
Invention is credited to Alexander, Graham, Burky, Thomas E., Fisher, Michael L., Givens, Richard W., Klein, Jerome A., Paugh, Jason E..
Application Number | 20050126420 10/938199 |
Document ID | / |
Family ID | 34656956 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050126420 |
Kind Code |
A1 |
Givens, Richard W. ; et
al. |
June 16, 2005 |
Wall breaching apparatus and method
Abstract
Wall breaching apparatus and methods utilizing shaped charges
for penetration of walls of buildings and other structures for
rescue, escape, or military operations.
Inventors: |
Givens, Richard W.;
(Columbus, OH) ; Fisher, Michael L.; (Granville,
OH) ; Burky, Thomas E.; (Johnstown, OH) ;
Klein, Jerome A.; (Raymond, OH) ; Alexander,
Graham; (Blacklick, OH) ; Paugh, Jason E.;
(Columbus, OH) |
Correspondence
Address: |
BATTELLE MEMORIAL INSTITUTE
505 KING AVENUE
COLUMBUS
OH
43201-2693
US
|
Family ID: |
34656956 |
Appl. No.: |
10/938199 |
Filed: |
September 10, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60501815 |
Sep 10, 2003 |
|
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|
Current U.S.
Class: |
102/310 |
Current CPC
Class: |
F42B 3/02 20130101; F42B
1/02 20130101; F42D 3/00 20130101; F42B 3/08 20130101 |
Class at
Publication: |
102/310 |
International
Class: |
F42B 001/00 |
Claims
We claim:
1. A kit for constructing a wall breaching structure, the kit
comprising: a. a plurality of linear shaped charges; b. a plurality
of block explosive charges; and c. a plurality of connecting
members for connecting any of the shaped charges and the block
explosive charges to others of the shaped charges and the block
explosive charges; and wherein the shaped charges and the block
explosives can be configured into a multiplicity of different
arrangements and connected together to form a wall breaching
structure.
2. A wall breaching apparatus comprising: a. a plurality of linear
shaped charges; b. a plurality of block explosive charges; and c. a
plurality of connecting members for connecting any of the shaped
charges and the block explosive charges to others of the shaped
charges and the block explosive charges; and wherein the shaped
charges and the block explosives can be configured into a
multiplicity of different arrangements and connected together to
form a wall breaching structure.
3. A method of breaching a non-homogeneous reinforced aggregate
structure, the method comprising: a. placing the linear shaped
charge against the non-homogeneous reinforced aggregate structure,
the structure having a plurality of reinforcement members; and b.
exploding the linear shaped charge to generate a metal jet and a
blast wave, and wherein the metal jet cuts at least one of the cut
reinforcement members at one location and the remainder at two
locations and the blast wave creates an opening in the aggregate
material, and wherein the cutting of the reinforcement member and
the creation of the opening occur substantially simultaneously.
4. The method according to claim 3, wherein the metal jet cuts at
least about 10% to 75% of the cut reinforcement members at one
location and the remainder at two locations.
5. The method according to claim 3, wherein when double rebar is
used the metal jet cuts at least two of the cut reinforcement
members at one location and the remainder at two locations.
6. A method breaching a non-homogeneous reinforced aggregate
structure, the method comprising: a. placing an explosive charge
configured to define a portion of a perimeter of an opening to be
formed against the non-homogeneous reinforced aggregate structure,
the structure having a reinforcement member; and b. exploding the
explosive charge, and wherein a blast created by the explosive
charge creates an opening in the aggregate material, cuts the
reinforcement member in one location, and bends the reinforcement
member substantially at the portion of the perimeter of the opening
in a direction of the blast, such that a person can travel through
the opening thereby created.
7. The method according to claim 6, wherein the explosive charge
cuts at least about 10% to 75% of the cut reinforcement members at
one location and the remainder at two locations.
8. The method according to claim 6, wherein when double rebar is
used the explosive charge cuts at least two of the cut
reinforcement members at one location and the remainder at two
locations.
9. An initiation mechanism for igniting a linear shaped charge
comprising: a. a linear shaped charge having a metal liner; b. a
plurality of detonators attached to the linear shaped charge; and
c. a mechanism for simultaneously igniting the plurality of
detonators; and wherein the simultaneous ignition of the plurality
detonators creates a substantially planar detonation wave.
10. A method of creating a substantially planar detonation wave,
the method comprising: a. providing a linear shaped charge having a
metal liner; b. attaching a plurality of detonators to the linear
shaped charge; and c. igniting the plurality of detonators with a
mechanism for simultaneously igniting the plurality of detonators;
and d. wherein the simultaneous ignition of the plurality
detonators thereby creates a substantially planar detonation
wave.
11. An initiation mechanism for igniting a linear shaped charge
comprising: a. a linear shaped charge having a metal liner; b. a
first detonator attached to the linear shaped charge; c. a second
detonator attached to the linear shaped charge; d. an intermediate
detonator attached to the linear shaped charge and disposed between
the first detonator and the second detonator; and e. a mechanism
for simultaneously igniting the first, second, and intermediate
detonators, and wherein the simultaneous ignition of the plurality
first, second, and intermediate detonators thereby creates a
substantially planar detonation wave.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/501,815, filed Sep. 10, 2003.
[0002] The full disclosure of the parent provisional application is
incorporated herein by reference.
FIELD OF THE INVENTION
[0003] This invention provides a portable easily deployable
apparatus for wall breaching in both civilian and military
environments. The apparatus has particular use in rescue operations
where persons may be trapped inside buildings or in providing
escape from an enclosed environment. Other uses include forced
entry into buildings or other structures.
BACKGROUND OF THE INVENTION
[0004] Conventional shaped charges can be used to defeat targets
such as reinforced concrete and typical structural materials such
as brick, stone, wood and the like. However, conventional apparatus
for breaching targets lack the ability to attack widely variable
targets, are typically heavy and cumbersome to carry. Typical prior
art devices are exemplified by U.S. Pat. No. 3,838,643 to Austin et
al.; U.S. Pat. No. 4,430,939 to Harrold; U.S. Pat. No. 4,905,601 to
Gabriel et al.; U.S. Pat. No. 5,036,771 to Alford; and U.S. Pat.
No. 5,524,546 to Rozner et al.
BRIEF DESCRIPTION OF THE INVENTION
[0005] The present invention includes several broad embodiments. A
first broad embodiment includes a kit that can be used for
constructing a wall breaching structure. The kit is made up of a
plurality of linear shaped charges; a plurality of block explosive
charges; and a plurality of connecting members for connecting any
of the shaped charges and the block explosive charges to others of
the shaped charges and the block explosive charges; typically the
shaped charges and the block explosives can be configured into a
multiplicity of different arrangements and connected together to
form a wall breaching structure.
[0006] A second broad embodiment includes an apparatus produced
from the kit that includes, a plurality of linear shaped charges; a
plurality of block explosive charges; and a plurality of connecting
members for connecting any of the shaped charges and the block
explosive charges to others of the shaped charges and the block
explosive charges; typically the shaped charges and the block
explosives can be configured into a multiplicity of different
arrangements and connected together to form a wall breaching
structure.
[0007] A third broad embodiment includes a method for breaching a
structure such as a wall and the like with a reduced weight charge.
The method provides for simultaneous cutting of rebar and blast of
an opening using a light shaped charge typically less than about 60
pounds. Typically the method includes the steps of providing a
metal lined linear shaped charge having a weight of less than about
60 pounds; placing the linear shaped charge against the
non-homogeneous reinforced aggregate structure, the structure
having a reinforcement member; and exploding the linear shaped
charge to generate a metal jet and a blast wave, wherein the metal
jet cuts the reinforcement member at at least one location and the
blast wave creates an opening in the aggregate material, and
wherein the cutting of the reinforcement member and the creation of
the opening occur substantially simultaneously.
[0008] A fourth broad embodiment includes provides for using
non-continuous polygon shaped wall breaching apparatus. The method
includes the steps of placing an explosive charge configured to
define a portion of a perimeter of an opening to be formed against
the non-homogeneous reinforced aggregate structure, the structure
having a reinforcement member; and exploding the explosive charge,
wherein a blast created by the explosive charge creates an opening
in the aggregate material, cuts the reinforcement member in one
location, and bends the reinforcement member substantially at the
portion of the perimeter of the opening in a direction of the
blast, such that a person can travel through the opening thereby
created.
[0009] A fifth broad embodiment includes an initiation mechanism
for firing a linear shaped charge. The mechanism typically includes
a linear shaped charge having a metal liner; a plurality of
detonators attached to the linear shaped charge; and a mechanism
for simultaneously igniting the plurality of detonators; wherein
the simultaneous ignition of the plurality detonators creates a
substantially planar detonation wave. A yet further embodiment of
the invention includes a method for making a substantially planar
detonation wave. One method includes creating a substantially
planar detonation wave, by the steps of providing a linear shaped
charge having a metal liner; attaching a plurality of detonators to
the linear shaped charge; and igniting the plurality of detonators
with a mechanism for simultaneously igniting the plurality of
detonators; and wherein the simultaneous ignition of the plurality
detonators thereby creates a substantially planar detonation wave.
Another method for igniting a linear shaped charge includes the
steps of providing a linear shaped charge having a metal liner; a
first detonator attached to the linear shaped charge; a second
detonator attached to the linear shaped charge; an intermediate
detonator attached to the linear shaped charge and disposed between
the first detonator and the second detonator; and a mechanism for
simultaneously igniting the first, second, and intermediate
detonators, and wherein the simultaneous ignition of the plurality
first, second, and intermediate detonators thereby creates a
substantially planar detonation wave.
[0010] Typically the methods according to the invention provide
that the metal jet and/or explosive charge cuts at least about 10%
to 75% of the cut reinforcement members at one location and the
remainder at two locations. In some embodiments the where double
rebar is used the metal jet and/or explosive charge cuts at least
two of the cut reinforcement members at one location and the
remainder at two locations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is set of two diagrams depicting extended (FIG. 1A,
top diagram) and partially folded (FIG. 1B, bottom diagram) of an
apparatus according to the invention.
[0012] FIG. 2 is set of schematic diagrams depicting a frontal view
(top diagram) and a side view (bottom diagram) of the linear charge
arrangement according to the invention.
[0013] FIG. 3 illustrates the effect of standard linear shaped
charge initiation on liner collapse factors as in the prior
art.
[0014] FIG. 4 illustrates the effect of multiple initiation points
on wave shaping for the apparatus according to the invention.
[0015] FIG. 5 illustrates is a frontal view of wave fronts for
simultaneous initiation using hemispherical wave shaper
initiations.
[0016] FIG. 6 illustrates side (left diagram) and frontal views
(right diagram) for pyramidal wave shaper initiation.
[0017] FIG. 7 illustrates a four point initiation
configuration.
[0018] FIG. 8 illustrates detonating cord down-line connectors and
how they would mate.
[0019] FIG. 9 illustrates a complete initiation system with
hemispherical wave shapers, three point initiation, down-line
connectors and central hub
[0020] FIG. 10 illustrates a top view of a typical wall breaching
apparatus according to the invention and a side view of a linear
shaped charge.
[0021] FIG. 11 illustrates a schematic for a typical "basic"
configuration as discussed herein.
[0022] FIG. 12 illustrates a schematic for a "concept L"
configuration as discussed herein.
[0023] FIG. 13 illustrates a schematic for a "concept C"
configuration as discussed herein.
[0024] FIG. 14 illustrates a schematic for a "concept parallel"
configuration as discussed herein.
[0025] FIG. 15 illustrates a schematic for a "concept Y"
configuration as discussed herein.
DETAILED DESCRIPTION OF THE INVENTION AND BEST MODE
[0026] The wall breaching apparatus typically includes a quickly
deployed, fully contained, modular explosive charge. The wall
breaching apparatus typically includes a folding template, linear
shaped charges, integral initiation system, and attachment system.
The attachment system typically is a mini-stun gun attachment or a
(support) prop pole to hold the system in place. Other methods for
attachment known in the art may be used. There are two different
embodiments for the folding template that will trade-off deployment
time and cost/weight.
[0027] The wall breaching apparatus is modular so that it can be
used against differing target wall designs. One embodiment of a
typical wall breaching apparatus (typically six segments forming a
hexagon, approximately 23 pounds net explosive weight) will breach
the concrete and both layers of rebar contained in an 8 inch thick
double layer reinforced poured concrete wall producing at least a
36 inch diameter hole. A typical three segment system (three
segments separated by 120 degrees, approximately 12 pounds net
explosive weight) will breach a triple layer brick wall. A typical
two segment system (two segments separated by 180 degrees,
approximately 8 pounds net explosive weight) will breach CMU and
brick-on-block walls.
[0028] Detailed below are typical deployment embodiments and
methods, designs for the templates, initiation systems, and
explosive charges.
[0029] The invention provides for a kit that can be used for
constructing a wall breaching structure. The kit is made up of a
plurality of linear shaped charges; a plurality of block explosive
charges; and a plurality of connecting members for connecting any
of the shaped charges and the block explosive charges to others of
the shaped charges and the block explosive charges; typically the
shaped charges and the block explosives can be configured into a
multiplicity of different arrangements and connected together to
form a wall breaching structure.
[0030] The shaped charges contained in the kit are linear shaped
charges. The standard cross sectional design of a typical linear
shaped charge has straight sides extending from a single included
angle. This conventional linear shaped charge design is economical
to produce but is not the best based on weight and performance. The
design of the shaped charges for this wall breaching system follow
convention for high performance design of conical shaped charges
typically used for armor defeat in military applications, instead
of the convention for linear charges. Because of this the choice
available for cross section designs is much more varied. The cross
sections in this case can include the following patterns:
straight-sided, "trumpet" shaped, "tulip" shaped, and "bi-conic"
shaped. Using these additional shapes it is possible to obtain
better performance than the standard straight-sided approach.
[0031] The materials used to construct the shaped charge liners
useful in this wall breaching kit can include: copper, tantalum,
silver, gold, aluminum, composites of metals, alloys of these
metals, composites of these metals with fluorocarbon polymers,
other malleable metals, glass and mixtures thereof.
[0032] The block explosives used in the kit can typically be high
velocity explosives such as the standard M112 demolition block
which consists of 1.25 pounds of plastic explosive. Other block or
bulk explosive charges could be used, including: one pound TNT
demolition blocks, cartridges of either military or commercial
dynamite, cast pentolite boosters, flexible sheet explosive or
detonating cord charges.
[0033] The connecting members and other supporting or enclosing
parts of the kit or apparatus according to the invention are
typically constructed of lightweight and strong materials with the
desire being to minimize the amount of fragmentation created during
the detonation of the wall breaching charges. These construction
materials may include: wound carbon fiber, carbon fiber composite,
an aluminum/polymer composite, fiberglass or other polymer
composite. The connecting members will be able to deploy the
explosive charges from a folded, compact arrangement into an
extended position in the final moments before breaching the wall
target. The connecting members will perform this deployment by
either unfolding or extending by applied gas pressure or mechanical
force.
[0034] Another aspect of the invention is an apparatus produced
from the kit that includes, a plurality of linear shaped charges; a
plurality of block explosive charges; and a plurality of connecting
members for connecting any of the shaped charges and the block
explosive charges to others of the shaped charges and the block
explosive charges; typically the shaped charges and the block
explosives can be configured into a multiplicity of different
arrangements and connected together to form a wall breaching
structure. The constituents of the apparatus are typically those
described earlier for the kit.
[0035] Deployment Method
[0036] A preferred embodiment such as an umbrella template is
designed for quick deployment and the reduction of time-on-target.
FIG. 1 shows the umbrella template with attached explosive charges.
The following steps are used to deploy the umbrella template
version of the modular breaching system:
[0037] 1. Pull contents out of a carrying bag (not shown)
[0038] 2. Approach wall;
[0039] 3. Place front end of device on wall while making sure that
the (support) leg is firmly planted. In poor weather conditions
stakes may be used;
[0040] 4. Deploy umbrella template by pushing sleeve towards
wall;
[0041] 5. While holding deployed device against wall, anchor charge
to the wall by firing two stud guns (not shown) through attachment
pads (not shown) if necessary;
[0042] 6. Prime central hub 111 with either one or two standard
detonator systems (e.g. time delay firing unit, shock-tube, etc);
and
[0043] 7. Retreat to safe area and fire breaching charge.
[0044] Another embodiment of the invention provides for a Compact
Template 200 that consists of three (3) jointed sections shown
either as 211 or 213 in Diagram 2A. Diagram 2B shows the jointed
sections 211 or 213 partially assembled. Individual shaped charges
201 are shown as part of the set. See diagrams 2A, 2B, 2C and 2D in
FIG. 2. The three sections can be joined by pins 215 to create a
hexagon (diagram 2C) that can be used to make a thirty-six inch
hole in a rebar reinforced concrete wall, lesser sections can be
used in configurations described herein, or a single section can be
deployed against smaller targets, such as lesser walls. Diagram 2D
is a side view of the assembly. The following steps are used to
deploy the compact template version of the modular breaching
system:
[0045] 1. Pull contents out of carrying bag (not shown);
[0046] 2. Assemble the hexagon or other figure;
[0047] 3. The six sides are folded in the middle via hinge, unfold
the hinge and slide lock pin in place;
[0048] 4. Connect the six sides together to form a hexagon, hook
inside and slide pin on outside (note hook is integral and slide
pins are permanently attached);
[0049] 5. Attach the two mini-stud guns,
[0050] 6. Connect the detonation cords from the distributor into
the legs of the hexagon;
[0051] 7. Carry assembled hexagon to the wall;
[0052] 8. While holding device against wall, anchor hexagon to wall
by firing two or more stud gun studs (not shown) through attachment
pads (not shown);
[0053] 9. Prime central hub 111 with either one or two standard
detonator systems (e.g. time delay firing unit, shock-tube,
etc);
[0054] 10. Retreat to safe area and fire breaching charge.
[0055] Referring again to FIGS. 1A and 1B, the umbrella type system
100 includes a leg support made up of a leg base 101, a straight
leg portion 103, connector 105, and angled leg 107. These provide
support to hub 111 which in turn provides support to linear shaped
charges 109 with connection members 113 that are connected to both
the charges 109 and the hub 111. End stop 115 and stop connector
117 complete the assembly.
[0056] Initiation System for the Wall Breaching Apparatus
[0057] The initiation mechanism of the wall breaching apparatus is
a key contributor to its enhanced performance over standard linear
shaped charges. A simultaneous line initiation along the entire
back of the charge allows for the classical collapse sequence of
the angled liner. With this method, the detonation wave planes from
a circular pattern at the point source into a horizontal line. This
planar detonation wave sweeps across the angled liner from the apex
to the base of the liner's triangular shape. This collapse profile
allows for the plastically deformed metal from both sides of the
liner to impact at the stagnation point and jet efficiently towards
the target. The cross-sectional view of this reaction in the wall
breaching apparatus is very similar to that of a classical conical
shaped charge.
[0058] This contrasts with the detonation methodology of a standard
linear shaped charge. This device is normally initiated from the
ends of each charge as shown in FIG. 3. The detonation front for
such an initiation travels perpendicular to the angled liner. This
detonation method does not permit the Chapman-Jouguet (CJ) front to
collapse the liner in the desired manner, from the apex to the
base. This side on method would initiate collapse at the front edge
of the CJ front. This collapse point may not be the apex of the
liner. The side on wave would also induce an X and Y component into
its jet's velocity vector. The X component, jet momentum parallel
to the target surface, would represent lost penetrating
ability.
[0059] The initiation method of the wall breaching apparatus
strives to achieve an apex to base collapse of the liner in a
direction that is tangent to the target as shown in FIG. 4. This
collapse progression of the wall breaching apparatus liner is like
that of a conical shaped charge. This maximizes the penetrating
ability of the charge. In order to achieve a planar detonation wave
shape, simultaneous multipoint initiation is used. The detonation
front from the multiple initiation sites collide midway between the
points. This integrated wave approaches a planar form much faster
than a detonation wave produced from a single initiation point.
This technique has a similar effect to wave shaping in conical
charges. FIG. 4 shows four detonators 401 and boosters 403 that are
used to fire a linear shaped charge 407. The detonators 401 produce
four wave fronts 405 that combine to produce a linear wave front
perpendicular to the target. The wave fronts 405 move much more
linearly from the apex 409 of the linear shaped charge 405 to the
bottom 411 in the Y direction than the prior art.
[0060] The initiation method used for wall breaching apparatus
assumes a simultaneous line initiation directly above the apex of
the liner along the entire length of each segment of the system.
This line initiation method is crucial to the charge performance.
An instantaneous detonation wave that collapses the liner from apex
to base results in a jet that is oriented directly at the target.
This line initiation forms a detonation wave that begins as a small
circle expanding outward through the explosive towards the liner.
As this circle expands with time, the circumference of the front
expands radially from the initiation point. From the reference
location of the liner, the expanding shape of the wave begins to
flatten and become somewhat planar. This flattened wave sweeps the
liner from apex to base. The time related contours of this wave can
be seen below in FIGS. 4, 5, and 7. As the detonation front sweeps
the liner, it transfers momentum into the liner material. The liner
material is then accelerated as a jet inward towards a linear axis
progressing from the apex to the base. The jets collide at a point
along this axis called the stagnation point. At the stagnation
point, the momentum is again redirected towards the base along the
axis. This redirected jet is oriented perpendicular to the target
for achieving maximum penetration.
[0061] Achieving an instantaneous line initiation along the back of
the charge is not easily accomplished. Referring now to FIGS. 6A
and 6B, these setups use sections of Primasheet.RTM. explosive cut
in the form of equilateral triangles. These triangles contain a
sequential series of holes cut in them at regular intervals. The
spacing between each of these holes also forms a progression of
equilateral triangles. These holes force a circular shaped
detonation front to curve around them. The equidistance around each
equilateral triangle force the detonation front to assume a planar
shape as it moves down the sheet.
[0062] A planar wave shape can also be achieved with simultaneous
multi-point initiation. Collisions of multiple circular shaped
detonation fronts congeal into an integrated wave front that has a
flattened appearance as it moves through the remaining un-reacted
explosive. The spacing between multiple initiation points
determines the degree of planarity that is achieved in the newly
formed wave. This can be observed in the drawing below. This
assumes that the detonation velocity is constant throughout the
explosive, as is most often the case.
[0063] Referring again to FIG. 3, a standard linear shaped charge
301 that is end initiated by detonator 303 and booster 305 results
in a detonation wave 306 that engulfs the liner 307 (see liner apex
311 and liner base 313) in an enlarging circular expansion focused
from the point source 309 and expanding along the longitudinal axis
of each charge. This wave geometry results in jets that move in an
angular direction to the target. This angular direction contains
vector components that are both parallel and at right angles to the
intended target. For future discussions, the parallel to target
directions will be defined as the "X" direction and the
perpendicular to target direction will be defined as the "Y"
direction. The shape of this detonation front results in a unique
jet shape. The jet vector from the top portion of the liner is
moving primarily in the "X" direction. Accordingly, the jet vector
from the base of the liner is moving mainly in the "Y" direction.
The focusing jet from the liner collapse is moving in a gradient
from the apex to the base. It would appear as an inverted angle
traveling at an incidental angle to the liner. The jet's gradated,
angular formation helps to explain the comparatively short length
jets that result from end initiating a standard linear shaped
charge.
[0064] This phenomenon was observed in a test performed in a small
mockup of hexagonal breaching charge using standard 2,000
grains/foot linear shaped charge, loaded with 70/30 Octol. This
test device was shot at a {fraction (1/2)} inch thick steel target.
The six segments of the charge were sized to fit inside a 4 inch
inscribed circle. Each segment was simultaneously initiated at its
midpoint. This initiation technique resulted in collision of 12
separate and inverted angular jets at the corners of the hexagon.
Because of the inverted angular shape of the colliding jets,
expanded penetration of the target was achieved. The initial
collisions occurred along the "Y" axis of the angular liner. After
the bottom of the center point of the jets collided along the liner
axis, the collisions began to occur outward and away from the
liner's centerline. These collisions resulted in expanded
penetration in the target opposing the connecting corners of the
assembled hexagon.
[0065] The present invention uses multiple firing points that
enhance the planarity of the detonation wave and maximize the "Y"
component of the jet.
[0066] Referring now to FIG. 5, hemispherical shaped boosters 501
between the detonators 503 and planar shaped charge 505 are one
embodiment that can expand the distributed detonation front area
from multi-point initiation along the charges back. These
hemispheres 501 would contain a phenolic material or similar acting
material inside its interior to prevent the shock wave from passing
straight through the booster in a spherical shape. The explosive
would comprise a shell configuration 507 around the half circle's
perimeter. At the charge contact point, the detonation from would
be in the shape of a ring. As the front 509 expands inward and
outward from the ring, the colliding waves result in a greatly
flattened shape. The wave which started at the top 511 of the
linear shaped charge is much flatter in appearance when it reaches
the bottom 513 than single point initiation in the same three
locations.
[0067] Another shape with a unique advantage in wave shaping is a
pyramid shape whose bottom side is at the width of the top of the
charge has symmetrical advantages along both the charges
cross-section and length. See FIG. 6A (cross sectional view) and 6B
(side view). In the configuration shown 600 a plastic fixture holds
the linear shaped charge 603 and detonator holders 604. The linear
shaped charge is fired with pyramidal wave shapers 605 between the
detonators 607 and the high explosive 609 of the linear shaped
charge 603. Typically a copper liner 611 is used with the shaped
charge as shown. Liner apex 613 and liner base 615 are typical as
shown. Optionally legs 619 may be used to offset the linear shaped
charge 603. Attachment points 621 are those typically used in the
art.
[0068] Another configuration for producing satisfactory wave
shaping is to use multiple point initiation as seen in FIG. 7. In
this case four detonators 701 are used per wall breaching apparatus
section 700. For six sections this results in 24 total detonators
crimped to detonating cord leads. Each section of four cords is
typically connected to a single cord lead using custom down-line
connectors. These connectors ensure an explosive train from the
single 150 grain cord to the four 50 grain cords. The six 150 grain
cords are embedded into the central hub and are initiated by a
Primasheet.RTM. booster and the firing device detonator. This
embodiment uses boosters 705 between detonators 701 and linear
shaped charge 703. The top of the charge is at 709 and the bottom
at 711. The combined wave shape 713 is much more planar and results
from the combination of waves from the multiple detonation points
715.
[0069] FIG. 8 is a schematic showing cord line connectors 801 and
how they would mate from the central hub 803 for three detonation
points per linear shaped charge.
[0070] FIG. 9 illustrates an eight sided polygon configuration 900
with eight linear shaped charges 901, three hemispherical wave
shapers 903 and associated detonators, central hub, and down line
connectors 907.
[0071] Referring now to FIGS. 10A and B, these illustrate a four
point polygon configuration 1000 with eight linear shaped charges
1001, four detonators 1003, central hub 1005, and down line
connectors 1007. A blown up view of the linear shaped charge 1001
is shown in FIG. 10B having a liner 1011, enclosure 1013, and
explosive 1015.
[0072] One embodiment for the wall breaching apparatus 1100 is a
set of six linear shaped charges 1101 arranged in a hexagonal
shape. This embodiment is the basic embodiment. See FIG. 11. The
charge will be initiated at multiple points on each linear charge
in an effort to maintain a planar shock wave during the liner
collapse event. Connection members 1103, central hub 1105 and leg
1105 provide support.
[0073] A preferred material for the shaped charge liner is copper,
however other materials such as those listed above may be used. A
preferred high explosive for the wall breaching apparatus is
PBX-9501. This explosive was selected for its favorable combination
of high detonation velocity, good manufacturability, and good
sensitivity characteristics. Other explosives useful with the
invention include Octol, Composition A, composition B, LX-14, PAX
compositions and the like. Preferably a light weight material such
as a plastic material (e.g. polymethyl methacrylate) is used to
encase the high explosive of the wall breaching apparatus. Other
polymeric materials useful for encasing the high explosives include
polyethylene, polypropylene, fiberglass, carbon fiber composites,
and mixtures thereof.
[0074] Typical high strength materials that can be penetrated by
the invention include 7000 psi unconfined compressive strength
concrete and 50 Ksi yield strength reinforcing steel.
[0075] The modular breaching system according to the invention is
able to defeat concrete, concrete with single rebar, or concrete
with double rebar in a single shot. Further this system can be
tailored easily in the field to suit the specific target. This
reduces its weight and increases the speed of deployment. The
modular breaching system is based on the penetrating capabilities
of linear shaped explosive charges. This is the basic unit of
explosive power that is used to breach the target, but this new
particular breaching charge now opens up the ability to change the
fundamental approach to wall breaching, particularly hard targets
like reinforced concrete, to greatly reduce weight of the breaching
system.
[0076] The current approach to wall breaching of reinforced
concrete targets is to cut a roughly circular hole with a
penetrating explosive charge, usually sections of linear shaped
charge. This is shown below in what is termed the "Basic"
configuration (See FIG. 11). While this charge is highly effective
against the reinforced concrete wall targets (assuming the
explosive charge of the linear shaped charges clear the opening)
the overall charge is very heavy due to the high weight necessary
in penetrating charges. This current design to produce a 36"
diameter hole uses approximately 108 to 113" of linear shaped
charge. Concept basic can weight up to about 60 lbs.
[0077] This embodiment is based on the assumption that it is
required to cut both ends of the rebar in the wall in order to
effectively breach the target. But this is simply not the case. If
the penetrating charge can be counted on to reliably cut the rebar
in the wall then it is really only necessary to cut one end of the
rebar. The remaining long pieces of rebar will be bent out of the
way by the blast effect of the high explosive in the linear shaped
charge or in additional bulk explosives. Typically the bulk
explosives are of much lower weight per unit than the linear shaped
charges. This means that by using the present invention in
different geometric shapes that are designed to cut only one end of
the rebar the remaining wall section can be fractured and cleared
using bulk explosive charges (such as composition C-4 plastic
explosive) that are fired substantially simultaneously with linear
shaped charges. Discussed below are several different embodiments
of the modular breaching system that utilize this methodology and
their associated characteristics such as the expected reduction in
weight. All of these designs utilize the rapid deployment mechanism
and hub described elsewhere in this disclosure as shown in the
figures herein.
[0078] A further embodiment of the invention provides for using
non-continuous polygon shaped wall breaching apparatus. The method
includes the steps of placing an explosive charge configured to
define a portion of a perimeter of an opening to be formed against
the non-homogeneous reinforced aggregate structure, the structure
having a reinforcement member; and exploding the explosive charge,
wherein a blast created by the explosive charge creates an opening
in the aggregate material, cuts the reinforcement member in one
location, and bends the reinforcement member substantially at the
portion of the perimeter of the opening in a direction of the
blast, such that a person can travel through the opening thereby
created. Typical non-continuous polygon shaped apparatus is
illustrated in FIGS. 12-15.
[0079] First is "Concept L" 1200 shown in FIG. 12. This embodiment
1200 uses four (typically 18') linear shaped charge 1201 sections
arranged in an "L" shape associated with two blocks of C-4 plastic
explosive 1202 to clear the remainder of the hole and push the
rubble and rebar out of the way. Support is provided by connection
members 1203, hub 1205, and leg 1207. The designed arrangement and
simultaneous detonation of the explosive charges will cause
colliding shock waves to produce fractures in the concrete between
the charges and break up the concrete enough such that the bulk C-4
charges can clear the hole out. This principle of colliding shock
waves is repeat in each of the embodiments described. This
embodiment produces an approximately 36" square hole and utilizes
72" of linear shaped charge explosive charge. This reduces the
weight to approximately 80% of a fully circular "Basic"
configuration.
[0080] "Concept C" 1300, shown in FIG. 13, utilizes three 18"
linear shaped charges 1301, two bulk explosive charges 1302,
connection members 1303, hub 1305, and leg 1307 as shown. This
embodiment produces a more circular hole that is approximately 31"
in diameter and uses the colliding shock wave phenomena described
above. This embodiment uses a total of 54" of linear shaped charge
and therefore will weigh approximately 60% of the Basic
configuration.
[0081] Referring now to FIG. 14, "Concept Parallel" 1400 typically
utilizes four about 13-14" linear shaped charges 1401, two bulk
explosive charges 1402, connecting member 1403, hub 1405, and leg
support 1407 as shown. This embodiment produces a roughly circular
hole that is about 30 to 36" in diameter and uses the colliding
shock wave phenomena described above. This embodiment uses about a
52 to 56" of linear shaped charge and therefore will weigh
approximately 65% of the Basic configuration. The hole diameter is
about 113". A typical reinforced rebar spacing is about 8".
[0082] The concept parallel typically cuts the reinforcing bars in
reinforced concrete in one and/or two places per rebar, however not
all of the cut rebars are cut twice as is the case in a circular or
polygonal wall breaching system. In this system two parallel linear
shaped charges provide double cutting to only some rebars. The
system is typically placed against a wall to be breached so that
the parallel linear charges are at about a 45.degree. angle from
the vertical and the explosive charge initiated. The angle of
application may range from about 35.degree. to 55.degree. degrees.
Although some of the bars are only cut once the wall is still
penetrated either by the linear charges alone or with the aid of
one or more additional lightweight explosive charges that blow out
the wall. This system is typically of lower weight than a circular
or polygonal wall breaching system.
[0083] Referring now to FIGS. 15A and 15B, "Concept Y" 1500
utilizes three linear shaped charges 1501, connecting members 1503,
hub 1505, and leg support 1507 as shown. This embodiment is not
designed for breach reinforced concrete but rather is for triple
course brick or brick-on-block target walls. This embodiment
produces a roughly circular hole that is approximately 30" in
diameter. The vertical imprint is shown in FIG. 15B. Colliding
shock wave phenomena is much less important in these types of
targets. This embodiment will weigh approximately 50% of the Basic
configuration.
[0084] Another embodiment of the invention includes a method for
breaching a structure such as a wall and the like with a reduced
weight charge. The method provides for simultaneous cutting of
rebar and blast of an opening using a light shaped charge typically
less than about 60 pounds. Typically the method includes the steps
of providing a metal lined linear shaped charge having a weight of
less than about 60 pounds; placing the linear shaped charge against
the non-homogeneous reinforced aggregate structure, the structure
having a reinforcement member; and exploding the linear shaped
charge to generate a metal jet and a blast wave, wherein the metal
jet cuts the reinforcement member at at least one location and the
blast wave creates an opening in the aggregate material, and
wherein the cutting of the reinforcement member and the creation of
the opening occur substantially simultaneously.
[0085] A further embodiment includes an initiation mechanism for
firing a linear shaped charge. The mechanism typically includes a
linear shaped charge having a metal liner; a plurality of
detonators attached to the linear shaped charge; and a mechanism
for simultaneously igniting the plurality of detonators; wherein
the simultaneous ignition of the plurality detonators creates a
substantially planar detonation wave. The mechanism for
simultaneously igniting the linear shaped charges typically
includes a capacitive discharge pulse power unit, an explosively
driven power supply that provides an electrical pulse, and other
electrical pulse generators known in the art the associated
wiring.
[0086] A yet further embodiment of the invention includes a method
for making a substantially planar detonation wave. One method
includes creating a substantially planar detonation wave, by the
steps of providing a linear shaped charge having a metal liner;
attaching a plurality of detonators to the linear shaped charge;
and igniting the plurality of detonators with a mechanism for
simultaneously igniting the plurality of detonators; and wherein
the simultaneous ignition of the plurality detonators thereby
creates a substantially planar detonation wave.
[0087] Another method for igniting a linear shaped charge includes
the steps of providing a linear shaped charge having a metal liner;
a first detonator attached to the linear shaped charge; a second
detonator attached to the linear shaped charge; an intermediate
detonator attached to the linear shaped charge and disposed between
the first detonator and the second detonator; and a mechanism for
simultaneously igniting the first, second, and intermediate
detonators, and wherein the simultaneous ignition of the plurality
first, second, and intermediate detonators thereby creates a
substantially planar detonation wave. More than three detonators
than those outlined above may be used.
[0088] While the forms of the invention herein disclosed constitute
presently preferred embodiments, many others are possible. It is
not intended herein to mention all of the possible equivalent forms
or ramifications of the invention. It is to be understood that the
terms used herein are merely descriptive, rather than limiting, and
that various changes may be made without departing from the spirit
of the scope of the invention.
* * * * *