U.S. patent application number 10/567290 was filed with the patent office on 2007-06-21 for security mesh panel.
Invention is credited to Jeffrey S.K. Yeo.
Application Number | 20070138454 10/567290 |
Document ID | / |
Family ID | 34114579 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070138454 |
Kind Code |
A1 |
Yeo; Jeffrey S.K. |
June 21, 2007 |
Security mesh panel
Abstract
The present invention relates to a security panel (1), for
example for use in a security barrier, and to a method of forming
the security panel. The security panel (1), comprises an expanded
metal mesh (2), the mesh hating apertures (9) therethrough bounded
by a plurality of sides (11), at least one of said apertures (9)
having at least one side (11) to which is affixed a separate barbed
structure (4), the barbed structure having at least one barb (14)
extending in a plane of the panel (1) in towards another side (11)
of said aperture (9).
Inventors: |
Yeo; Jeffrey S.K.;
(Singapore, SG) |
Correspondence
Address: |
HOWREY LLP
C/O IP DOCKETING DEPARTMENT
2941 FAIRVIEW PARK DRIVE, SUITE 200
FALLS CHURCH
VA
22042-2924
US
|
Family ID: |
34114579 |
Appl. No.: |
10/567290 |
Filed: |
July 29, 2004 |
PCT Filed: |
July 29, 2004 |
PCT NO: |
PCT/SG04/00226 |
371 Date: |
July 18, 2006 |
Current U.S.
Class: |
256/2 |
Current CPC
Class: |
E04H 17/04 20130101 |
Class at
Publication: |
256/002 |
International
Class: |
B21F 25/00 20060101
B21F025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 5, 2003 |
SG |
200305400-4 |
Claims
1. A security panel (1), comprising an expanded metal mesh (2), the
mesh having apertures (9) therethrough bounded by plurality of
sides (11), at least one of said apertures (9) having at least one
side (11) to which is affixed a separate barbed structure (4), the
barbed structure having at least one barb (14) extending in a plane
of the panel (1) in towards another side (11) of said aperture
(9).
2. A security panel (1) as claimed in claim 1, in which said barbed
structures (4) are affixed to all sides (11) of said at least one
aperture (9).
3. A security panel (1) as claimed in claim 1, in which the barbed
structure (4) has a plurality of said barbs (14) extending in the
plane of the panel (1) in towards another side (11) of said
aperture (9).
4. A security panel (1) as claimed in claim 1, in which the barbed
structure (4) comprises a plurality of barbed points (15,16,17)
grouped in threes, a first (15) and a second one (16) of said
barbed points extending in opposite directions parallel with the
corresponding side (11) of said aperture (9), and the third one
(17) of said barbed points extending transversely away from the
corresponding side (11) of said aperture (9).
5. A security panel (1) as claimed in claim 1, in which said at
least one barb (14) has a plurality of barbed points (15,16,17),
each of said barbed points extending towards another side (11) of
said aperture (9).
6. A security panel (1) as claimed in claim 1, in which each side
(11) of an aperture (9) is formed from an elongate strip of metal
(6), each of said strips of metal being joined integrally to
adjacent strips of metal (6) at mesh nodes (8), the barbed
structure (4) being affixed to just one corresponding strip of
metal (6).
7. A security panel (1) as claimed in claim 6, in which the barbed
structure (4) is affixed to said one corresponding strip of metal
(6) at one or more points lying between said mesh nodes (8).
8. A security panel (1) as claimed in claim 6, in which the barbed
structure (4) lies entirely between mesh nodes (8).
9. A security panel (1) as claimed in claim 6, in which the barbed
structure (4) has a channel (12) with a complimentary shape to the
corresponding strip of metal (6) to which the barbed structure (4)
is affixed, the strip of metal (6) being seated in the channel (12)
when the barbed structure (4) is affixed to the corresponding strip
of metal (6).
10. A security panel (1) as claimed in claim 9, in which each barb
(14) has a corresponding base portion (18) that extends laterally
away from said channel (12) in the plane of the panel (1).
11. A security panel (1) as claimed in claim 10, in which the
barbed structure (4) has at least one pair of said barbs (14)
spaced along the length of the corresponding strip of metal (6) and
extending in the plane of the panel (1) in towards another side
(11) of the same aperture (9), each one of said pair of barbs (14)
having a base portion (18) that is distinct from base portions (18)
of any adjacent barbs (14).
12. A security panel (1) as claimed in claim 10, in which the
barbed structure (4) has one or more tabs (24) which wrap around
the corresponding strip of metal (6).
13. A security panel (1) as claimed in claim 12, in which said
tab(s) (24) is/are provided between base portions (18) of an
adjacent pair of barbs (14).
14. A security panel (1) as claimed in claim 12, in which the
barbed structure (4) has at least one pair of said barbs (14)
spaced along the length of the corresponding strip of metal (6),
and at least one of said tabs (24) is positioned between said
adjacent pair of barbs (14).
15. A security fence, comprising at least two upright fence
supports (32), and a security panel (1), said security panel being
supported by said fence supports (32), wherein the security panel
(1) is as claimed in claim 1.
16. A method of forming a security panel (1), comprising the steps
of: making a plurality of non-intersecting cuts in a sheet of
metal; expanding the cut sheet to form an expanded metal mesh (2),
the mesh having apertures (9) therethrough bounded by a plurality
of sides (11); forming one or more barbed structures (4) in metal
separate from the expanded metal mesh (2), the or each barbed
structure (4) having at least one extending barb (14); and affixing
at least one of said barbed structures (4) to a side (11) of at
least one of said apertures (9) so that at least one barb (14)
extends in a plane of the panel (1) in towards another side (11) of
said aperture (9).
17. A method of forming a security panel (1) as claimed in claim
16, in which the method comprises the step of affixing the or each
barbed structure (4) between a pair of nodes (8) of the metal mesh
(2).
18. A method of forming a security panel (1) as claimed in claim
16, in which the method comprises the steps of forming the barbed
structure (4) with at least one extending tab (24), and then
wrapping the or each tab (24) around portions of the metal mesh (2)
bounding the aperture (9) in order to affix the barbed structure
(4) to said side (11) of said aperture (9).
19. A method of forming a security panel (1) as claimed in claim
16, in which the method comprises the step of welding the barbed
structure (4) to the metal mesh (2) at one or more points between
nodes (8) of the metal mesh (2).
20. A security panel (1) as claimed in claim 6, in which the barbed
structure (4) has one or more tabs (24) which wrap around the
corresponding strip of metal (6).
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a security panel, for
example for use in a security barrier, and to a method of forming
the security panel.
BACKGROUND
[0002] Security barriers are conventionally formed from straight
sections of elongated metal tape having barbs formed at spaced
intervals along the tape. The metal tape may be traditional barbed
wire, which usually comprises two or more braided wires with
regularly spaced intertwined wire barbs. Alternatively, the metal
tape may be razor wire, which usually has a central wire with
laterally extending planar barbs. An example of such razor wire is
disclosed in U.S. Pat. No. 4,509,726.
[0003] It is known to form metal tape, and particularly razor wire,
into a security mesh panel in order to provide a barrier which is
both stronger and more secure than a barrier formed purely with
elongate parallel strands of metal tape. One such security mesh is
disclosed in patent document CA 1,190,433, which shows a security
mesh panel formed from straight razor wire that is bent into a saw
tooth pattern that interlinks with adjacent saw tooth bent razor
wires. The mesh is then riveted or welded at the junctions.
[0004] Other types of security mesh panel formed from razor wire
are disclosed in U.S. Pat. No. 4,666,129, GB 2,259,722 A, WO
00/65178 and 2,240,351 A, all of which are similar to CA 1,190,433
in that individual strands of razor wire are joined together by
welding or riveting to form a security mesh panel.
[0005] A number of problems have been noted with such security mesh
panels. First, a large number of individual strands of razor wire
have to be formed and aligned relative to one another prior to
fixing the strands together. In a production environment, this
requires specially designed machinery both to manipulate and join
the stands. Second, although in principle it is possible to make a
weld or rivet as strong as the surrounding material, in practice
each join is a potential source of weakness. For example, a weld
may not have been formed in the optimum manner. Both welds and
rivets are a potential source of corrosion, either from the use of
differing types of metals in the same structure, or from damage
done to a galvanized protective finish on the original razor
wire.
[0006] One solution to the latter problem is to form the razor wire
from stainless steel, but this is a prohibitively expensive
material to use in many applications, particularly perimeter
fencing formed from the security mesh panels.
[0007] It is an object of the present invention to provide a
security mesh panel that deals with these issues.
SUMMARY OF THE INVENTION
[0008] According to the invention, there is provided security
panel, comprising an expanded metal mesh, the mesh having apertures
therethrough bounded by a plurality of sides, at least one of said
apertures having at least one side to which is affixed a separate
barbed structure, the barbed structure having at least one barb
extending in a plane of the panel in towards another side of said
aperture.
[0009] Because the security panel is formed from an expanded mesh,
there is no need for welds or rivets at mesh nodes. The panel
therefore has an inherent strength and durability beyond that which
may be achieved with a security panel formed from individual
lengths of razor wire. Furthermore, there is no need for there to
be any welds or other joins between the barbed structures and the
mesh at the mesh nodes. Such joins can be made entirely away from
the mesh nodes. Therefore, the formation and performance of these
joins cannot adversely affect the strength of the mesh at the
nodes. Because any stresses on a security panel will tend to be
concentrated at one or more of the mesh nodes, the overall strength
of the security panel can readily be improved as compared with a
security panel having joins between individual pieces of razor
wire.
[0010] Preferably, the barbed structures are affixed to all sides
of said at least one aperture. This helps to provide the maximum
number of the barbs projecting into each aperture of the security
panel, thereby improving the security of the panel. Furthermore,
for the same reason the barbed structure may have a plurality of
said barbs extending in the plane of the panel in towards another
side of said aperture.
[0011] In one preferred embodiment of the invention, the barbed
structure includes a plurality of barbed points grouped in threes,
a first and a second one of said barbed points extending in
opposite directions parallel with the corresponding side of said
aperture, and the third one of said barbed points extending
transversely away from the corresponding side of said aperture.
[0012] In general, each side of an aperture is formed from an
elongate strip of metal, and each of the strips of metal is joined
integrally to adjacent strips of metal at mesh nodes. In a
preferred embodiment, the barbed structure is then affixed to just
one corresponding strip of metal. So that the fixing of the barbed
structure does not adversely affect the strength of the mesh nodes,
the barbed structure is preferably affixed to this one
corresponding strip of metal at one or more points lying between
the mesh nodes. Similarly, the barbed structure preferably lies
entirely between mesh nodes.
[0013] The invention further provides a security fence, comprising
at least two upright fence supports, and a security panel, said
security panel being supported by said fence supports, wherein the
security panel is according to the invention.
[0014] Also according to the invention, there is provided a method
of forming a security panel, comprising the steps of: making a
plurality of non-intersecting cuts in a sheet of metal; expanding
the cut sheet to form an expanded metal mesh, the mesh having
apertures therethrough bounded by a plurality of sides; forming one
or more barbed structures in metal separate from the expanded metal
mesh, the or each barbed structure having at least one extending
barb; and affixing at least one of said barbed structures to a side
of at least one of said apertures so that at least one barb extends
in a plane of the panel in towards another side of said
aperture.
[0015] The method may also comprise the step of affixing the or
each barbed structure between a pair of nodes of the metal
mesh.
[0016] One way of affixing the barbed structure to the metal mesh
is to form the barbed structure with at least one extending tab,
and then wrap the or each tab around portions of the metal mesh
bounding the aperture in order to affix the barbed structure to
said side of said aperture.
[0017] Additionally or alternatively, the barbed structure may be
affixed to the metal mesh by welding the barbed structure to the
metal mesh at one or more points between nodes of the metal
mesh.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention will now be further described, by way of
example only, and with reference to the accompanying drawings, in
which:
[0019] FIG. 1 is a plan view of one side of a security mesh panel
according to the invention;
[0020] FIG. 2 is an enlarged plan view of part of the opposite side
of the security mesh panel of FIG. 1;
[0021] FIG. 3 is a cross-section view through the security mesh
panel, taken along line III-III of FIG. 2; and
[0022] FIG. 4 is a view of a security fence, comprising upright
fence supports that support the security panel of FIGS. 1 to 3.
DETAILED DESCRIPTION
[0023] FIG. 1 shows a plan view of one side of a security mesh
panel 1. The security panel 1 is formed from a planar expanded
metal mesh 2 to which individual elongate metal barbed structures 4
have been permanently affixed, for example by spot welding. The
expanded mesh 2 is itself formed in a conventional manner from a
metal sheet, for example 3 mm thick mild steel, galvanized steel or
even stainless steel, through which a series of parallel
non-overlapping slits have been punched. After the slits have been
formed, a pair of opposite edges of the sheet is pulled apart to
expand the sheet and form the mesh 2. If the expanded metal sheet
requires corrosion protection, then it may be galvanized.
[0024] Reference is now made also to FIGS. 2 and 3, which show
respectively an enlarged plan view of a side of the security mesh 2
opposite to that shown in FIG. 1, and a cross section view through
the security mesh. The mesh 2 consists of a series of adjacent
strips of metal 6, which in this example are essentially straight
sections. Each straight section 6 is bounded by mesh nodes 8 at
which each straight section merges integrally with adjacent
straight sections 6. Each mesh node 8 is therefore joined to four
adjacent straight sections 6 in an X-pattern, except at an edge 10
of the mesh where each mesh node 8 is joined to two adjacent
straight sections 6 in a V-pattern.
[0025] The metal mesh 2 therefore presents a number of diamond
shaped apertures 9, each of which is bounded by four adjacent sides
11.
[0026] Each barbed structure 4 lies entirely between a pair of mesh
nodes 8, which are at opposite ends of a mesh straight section 6.
In the present example, there are three such barbed structures
between 4 each mesh node 8. There may, however, be one, two, four
or any convenient number of such barbed structures 4 between the
nodes 8.
[0027] The barbed structures 4 are all punched from sheet metal,
preferably galvanized steel or stainless steel and then folded
along a central axis to form a square U-shaped channel 12 that
extends the full length of each barbed structure 4. As can be seen
from FIG. 3, each straight section 6 has a square cross-section.
The cross section may, however, alternatively be rectangular. The
cross-section of the straight section has a complementary shape
with the U-shaped channel so that each barbed structure 4 is seated
securely on a corresponding straight section 6. Each straight
section 6 is therefore seated in the channel 12 when the barbed
structure 4 is affixed to the corresponding straight section 6.
[0028] Each barbed structure 4 is formed with at least one, and
preferably two or three barbs 14 along opposite sides of the barbed
structure. Here, the barbs 14 are multi-pointed. The number and
spacing of the barbs 14 will depend on the relative sizes of the
barbs 14 and aperture 9. The barbs 14 each have a pair of barbed
points 15, 16 that extend parallel with the length of the U-shaped
channel 12 and at a distance from the straight section 6. A third
intermediate barbed point 17 extends transversely away from the
channel 12 and straight section 6. Each of the barbed points 15,
16, 17 is triangular in plan view and extends in the plane of the
security mesh 2 towards another side 11 of the aperture 9.
[0029] When the barbed structures 4 are being assembled with the
metal mesh 2, the complimentary square shapes of each straight
section 6 and corresponding barbed structure 4 hell to align the
barbed structure 6 with the plane of the metal mesh 2. This greatly
simplifies the manufacturing process, as it is not necessary to
hold each barbed structure 4 in place prior to permanent affixing
of the barbed structure 4 to the corresponding straight section
6.
[0030] In order to make each barbed point 15, 16, 17 as sharp as
possible, the barbed structure 4 is preferably stamped from
relatively thin sheet metal, for example between 0.3 mm and 0.5 mm
thick. The barbs 14 should, however, be difficult to bend back by
hand, and in order to reinforce each barb 14 against such bending,
each barb 14 has a corresponding base portion 18 that extends in
the plane of the mesh panel 2 laterally away from the channel 12.
Each barb 14 has a central waist 20 from which the three barbed
points 15, 16, 17 project and from which the base portion 18 flares
outwards towards the channel 12. This arrangement of base portion
18 and waist 20 therefore permits each barb 14 to be spaced at a
sufficient distance from the straight section 6 to provide enhanced
security, while at the same time diminishing the distance between
the waist 20 and the barbed points 15, 16, 17 in order to reduce
the amount of leverage that may be applied in an attempt to bend
back a barbed point 15, 16, 17.
[0031] The outwardly flared shape of the base portion 18 also makes
the pair of parallel barbed points 15, 16 more exposed, thus
increasing the deterrent effectiveness of these barbed points 15,
16. For this reason, each base portion 18 is distinct from base
portions of any adjacent barbs 14.
[0032] The effectiveness of each barb 14 is also enhanced if there
is a longitudinal spacing between adjacent parallel barbed points
15, 16 at least as great as the lateral spacing of each of these
points from the central channel 12. Therefore, it is particularly
preferred that each base portion 18 is separated by a gap 22 from
adjacent base portions 18.
[0033] Furthermore, this arrangement permits the barbed structure 4
to have one or more tabs 24 which wrap around the corresponding
straight section 6 to which the barbed structure 4 is affixed. In
the illustrated embodiment, there is a pair of such tabs 24 spaced
along the length of the corresponding strip of metal 6 and which
extend from opposite sides 25, 26 of the channel 12. The tabs 24
enhance the join between the barbed structure 4 and the
corresponding straight section 6, and may be wrapped around the
straight section 6 prior to welding in order to ensure that each
straight section 6 is held securely in place prior to permanent
affixing of the barbed structure 4 to the straight section 6.
[0034] The tabs 24 may be used to hold the barbed structures 4 to
the corresponding straight section 6 prior to welding of the barbed
structure to the straight section. In an alternative embodiment,
not illustrated in the drawings, the barbed structures 4 have no
tabs, but are crimped to the corresponding straight section 6, the
crimping being sufficient to hold the barbed structure in place
prior to permanent fixing, for example by welding.
[0035] The security panel 1 described above may be used in various
applications where a panel-type security barrier is needed. The
security panel 1 may form only a portion of a security barrier, for
example a security strip atop a wall or fence, or may form all or
substantially all of a security barrier. An example of the latter
application is illustrated in FIG. 4, which shows a security fence
30 comprising at least two upright fence supports 32, which may be
secured in the ground 34, with the security panel 1 being supported
by the fence supports 32. Because of the solid interconnection
between the strips of metal 6 at integral mesh nodes 8, such a
security fence 30 is very strong compared with mesh structures in
which initially separate strips have been subsequently secured
together by welding or riveting.
[0036] In summary, there a number of advantages to forming the
security panel 1 from an expanded metal mesh 2 to which a number of
separate barbed structures 4 are affixed. First of all, the fixing
of the barbed structures 4 and the mesh 2 does not adversely affect
the strength of the mesh. Corrosion of a metal mesh 2 is a
particular problem at mesh nodes, and because each mesh node 8 in
the expanded metal mesh 2 is not subject to subsequent welding,
riveting or the like, each mesh node 8 will tend to be less
susceptible to corrosion. The security panel 1 of the invention
therefore does not need to be formed in expensive materials such as
stainless steel in order to form a durable security barrier.
[0037] The particular form of barbed structure 4 and mesh straight
section 6 described above also provides significant advantages,
both in terms of the assembly of the structure and the ultimate
deterrent value of the security mesh structure.
[0038] The invention therefore provides an economical and
convenient security panel that may be used in a range of different
security applications.
* * * * *