Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
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Field of the Invention
The present invention relates to an intruder barrier and
in particular, to an intruder barrier of the type which
is rotatably mounted on the top of a wall whereby a person
attempting to pass over the barrier is prevented from
obtaining an effective hand-grip on either the wall or
barrier.
Description of the prior art
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In many instances where security devices are required, they
are not required to provide an absolute bar to the
professional or skilled thief but are more often required
to deter vandals or, for example, where there is a likeli-
hood of danger, to prevent children and other unauthorised
personnel entering a premises. This is particularly the
case, for example, in power stations and the like premises
where the perimeter walls, fences and portions of the
building must be so protected as to prevent children an`d
other unauthorised personnel climbing on to or over them.
Thus, there are many cases where the security device is
not so much to prevent unauthorised entry of the profess-
ional thief as to provide a safety device which will prevent
untoward accidents. Needless to say, in the latter cas
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the security aspect is also important.
Static barriers are well known such as for example, spiked
railings, barbed wire or pieces of broken glass embedded in
the top of the wall. While some of these methods may
restrict the activities of vandals unfortunately, they are
not particularly efficient and can be readily easily
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overcome. More importantly they present a considerable
safety hazard~
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Further it is known from British Patent Specification No.
.1
612,265 to provide apparatus for preventing or obstructiny
the scaling of walls, fences or the like barrier which
~; comprises a substantially cylindrical member constituted
` by a series of rods, bars or sheet material arranged
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~ around the perimeteres of a number of co-axial discs to
7 15 produce a cage-like body mounted to rotate on bearing
brackets adapted to be secured to the top of a wall or
fence. Such devices conslst,~ln thelr slmplest form,
; ~ of a substantially cyl~indrical~ member~mounted in bearings
to rota~te on a substantially horizontal axis along a wàll
20 or fence top whereby a person attempting to pass over
the barrier is prevented from obtaining an effective
handgrip on the wall or barrier which rotates. These
devices can be readily easily jammed in one position so
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that it is then only a question of climbing over a
stationary barrier. Thus these devices while more suitable
than spiked railings, barbed wire or capping members with
inserted broken glass are not, unfortunately, as suitable
as they could be for the purpose.
In Deutsche ~ffenlegungsschrift 2,206,436 there is described
an intruder barrier substantially similar to the
intruder barrier of British Patent Specification No. 612,265
except that this intruder barrier is mounted on a support so
as to be movable at least partly at right angles to its
longitudinal direction. Generally the device is roughly
vertically displaceable, however, this intruder barrier is
not necessarily any more efficient in use than the simpler
constructions of intruder barrier and additionally, is
more complex and costly to manu-Facture.
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The term "wall" is used in this specification not only to
designate a solid wall such as a conventional perimeter
wall but also a wall forming part of a building or any
type of fence or railing. Additionally, the term "wall"
includes the sides of any structure such as a tower or
structural steel building or support.
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The object of the present invention is to provide an
improved intruder.barrier of the type hereinbefore
described which will be efficient in operation while
at the same time relatively inexpensive to manufacture.
A further object of the invention is to provide an intruder
barrier which will not constitute a man-trap in use.
A still further object of the invention is to provide an
intruder barrier that will be particularly useful for
mounting on easy scale perimeter fences, for example,
chain link fences.
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SUMMARY OF THE INVENTION
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According to the invention there is provided an intruder
barri`er for mounting on the surface of a wall comprising:
a support shaft having a longitudinal axis; a support frame-
work on which the support shaft is mounted, for mountingthe support shaft on the wall with its longitudinal axis
substantially parallel to the surface of the wall; and
a scaling barrier mounted on the support shaft to be rotatable
about sai.d longitudinal axis, said scaling barrier being
formed by a plurality of blades substantially equi-spaced
circumferentially and radially arranged relative to said
; axis, each blade diverging from an apex formed by bending
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a sheet of material intermediate its ends, portions of the
material at the apex being cut away to interlock with the
apex of another sheet thus forming a hole for reception
of the support shaft.
In one embodiment of the invention each sheet forms a
pair of blades. Ideally when there are four blades the
; angle of the apex between each pair of blades is approx-
imately a right angle.
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The advantages of the present invention are many and it
may be mentioned that the apparatus can be manufactured
at a relatively low cost, is simple to erect and generally
; efficient in use. Further the invention does not constitute
! a man-trap or any other device that is likely to cause
damage to unauthorised intruders while, at the same time,
it prevents children or o~her less skilled personnel from
climbing the perimeter wall.
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The intruder barrier according to the present invention is
particularly suitable for mounting on easlly scaled peri-
- meter fences, for example, a chain-link fence. It provides
a more efficient barrier than the more conventional means
used, such as, the cranking of the uprights away from the
vertical, adjacent the top of the fence to provide an
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overhang or the use of barbed wire strands with the
attendant dangers to personnel and consequently to the
occupier under publ;c liability legislation.
lt should also be noted that a great advantage of the
present invention is that it is equally difficult to get
out of a premises as it is to get into it and~ therefore,
; it will deter anybody attempting to enter the premises
since he or she will be aware that there is no easy exit
back over the barrier.
When manufactured of a metal mesh such as weldmesh the
metal mesh is almost impossible to climb as the mesh tends
to sag and bend under weight while at the same time the
edge of the mesh is sufficiently sharp as to cut into a
persons hand if any pressure or load is applied and at the
same time there is no question of severe injury.
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BRIEF DESCRIPTION OF THE DRAWINGS
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Fig. 1 is an elevational view of an intruder barrier
according to the invention mounted on a wall,
Fig. 2 is a cross-sectional view in the direction of
the arrows V-V of Fig. 1, and
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Fig. 3 is an exploded view of portion of the intruder
barrier of Fig. 1.
DETAILED DESCRIPTION OF THE IN~ENTION :
~ Referring to the drawings, there is illustrated an intruder
: 5 barrier mounted on a wall 1. The intruder barrier comprises
a scaling barrier, indicated generally by the reference
numeral 2, formed by a plurality of blades 3 mounted for
rotation on a support shaft 5. The support shaft 5 forms
a longitudinal axis for the scaling barrier which is sub-
stantially parallel to the surface of the wall 1. A pair
of wall-engaging uprights, of which one is shown at 6,
form a support framework for the scaling barrier 2. The
. blades 3 are of open mesh or net configuration and in
,~: this embodiment are manufactured from expanded metal mesh.
The blades 3 are thus constructed of a semi-rigid material
~: which wi:ll deform under the load of a human intruder but
: at the same time is not easily deformable. The exposed
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edges of each blade 3 forms a relatively sharp cutting edge.
There may be more than one set of blades spaced apart along
~: 20 the support snaft 5. Preferably, the minimum spacing "A"
between the bottom of each blade 3 and the top surface of
the wall 1 is of the order of 12 cms while at the same time
~I the spacing between two adjacent blades 3 is so arranged to
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prevent somebody climbing beneath them and over the wall 1.
In use, the blades 3 deform to some extent and rotate freely
under load and this combination presents a formidable
barrier to a would-be vandal.
Intruder barriers having such deformable blades form the
subject of our co-pend;ng Application No. 320,171.
A pair of blades 3 is formed from the one sheet of material
being bent intermediate its ends to form an apex 8 from which
the two blades diverge at approximately a right angle. The
apices of two pairs of blades 3 interlock to form a hole 9
for reception of the support shaft 5.
It will be appreciated that it is not necessary that the
blades be manufactured from an expanded metal mesh material
nor indeed is it necessary to manufacture a pair of blades
from the one sheet of material. A blade may in fact be formed
by bending a sheet of material intermediate its ends and
cutting away portion of the material at theapex to interlock
with the apex of another blade or blades thus forming a hole
for the reception of a support shaft. An important adYantage
of a mesh or net like material is that there is no need to
cut away portion of the material at ~he apex. The additional
advantages of the use of a mesh configuration are firstly,
that there is relatively little resistance to air or wind
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passage therebetween and thus the blades will not rotate in
the wind. Another advantage ofthe use of expanded metal
mesh is that in addition to sagging and bend;ng under weight
and having sharp edges so as to cut into a persons hand the
actual material itself is sufficiently sharp as to make it
very difficult to grip or hold. Also it is very difficult
to cut expanded metal mesh as it has not got uniform cross-
sections such as, for example, conventional wire has. It
is, however, preferable that there be at least four blades
and in fact that when there are four blades that the angle
at the apex between each pair of blades is approximately
a right angle.
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Preferably, the intruder barriers according to the present
invention are generally of relatively short length as
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~ 15 shown thus further foiling an attempt to lock them for '!
`/~ scaling.
In a particularly suitable construction of intruder barrier
in accordance with the invention itis preferable that
there be at least four blades each pair of blades being
formed from the one sheet of the material. This has the
advantage of saving on material. Ideally when there are
four blades the angle at the apex between each pair of
blades should be approximately a right angle.
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As mentioned above the material forming each blade may be a
semi-rigid material deforming under load. Ideally the
material is not readily deformable, that is to say it is
not easily deformed under load but at the same time is
sufficiently deformable as to make it difficult to jam
or otherwise secure in one position.
In accordance with the invention the intruder barrier is
so adapted to be secured to the top o-F a wall and in use
project beyond one face thereof. Thus, when the intruder
barrier projects beyond the face oF the wall it is all
the more difficult to climb it.
Further the intruder barrier may be secured to or incorp-
orated in a vertical wall and adapted to project beyond
that face of the wall. This may be of considerable
; 15 importance where the wall is very high and it would be
dangerous if children were to climb to the top of the
wall and then fall when trying to climb over an intruder
bar ier on the top of the wall.
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