The present invention relates to security means intended for coupling to at least a part of
a shell of a substantially closed space, comprising a carrier on which a pattern of
electrically conducting members is arranged, wherein the means are connected to
registration means for registering a resistance change in the conducting members.
Such means are known and are particularly used to secure spaces which have to be
secured for whatever reason. Here can be envisaged relatively small spaces such as -
small - safes, electronics housings, security cases and value containers, but also larger
spaces such as for instance archive areas. By coupling at least a part of the shell of such
closable spaces - and preferably that part of the shell through which an unauthorized
person can most easily gain access to the space - to the security means according to the
preamble a detection of attempted forced entry by unauthorized persons into the space
can take place.
The operating principle of the above stated security means is based on a measurement of
a resistance change of the conducting members. The carrier with the electrically
conducting members which is coupled to the shell of the space for securing, preferably
along the surface thereof through which an unauthorized person could possibly gain
access to the secured space by means of forced entry, has a determined resistance. When
the pattern of electrically conducting members is for instance damaged or distorted, a
resistance change occurs which is registered by means of the registration means. These
latter can for instance be coupled to an alarm system so that an alarm is immediately set
into operation.
The security means discussed in the foregoing have a number of drawbacks however.
Firstly, it is found that the pattern of electrically conducting members along the
openings left clear by the pattern can usually be penetrated in relatively simple manner
with assist means suitable for the purpose in order to deactivate the electronic system,
introduce substances having an adverse effect on or disabling the operation of the
security means or even to remove the - valuable - goods situated in the secured space.
The security means are moreover found not to possess the desired sensitivity and to
respond over-sensitively in some cases and under-sensitively in other cases.
The present invention has for its object to provide security means as according to the
preamble which do not have the above stated drawbacks. The invention provides for this
purpose security means as according to the preamble which are characterized in that the
pattern of electrically conducting members is arranged on either side of the carrier and
that at least the aperture between the pattern of electrically conducting members is
provided with insulating material.
By providing the carrier on either side with a pattern of electrically conducting members
the danger of unnoticed penetration thereof is markedly reduced. The insulating material
situated between the conducting members protects the members against mechanical
damage during further operations such as coupling of the security means to the shell of a
space for securing. In addition, the presence of the insulating material prevents the
security means responding over-sensitively to for instance a treatment of the space for
securing in which the security means are applied which is somewhat rough but not
consistent with an attempted forced entry.
In a particular embodiment of the present invention the pattern of electrically
conducting members is formed in tracks and the electrically conducting tracks cover a
larger surface area than the intermediate insulating material.
The danger of unnoticed penetration of the pattern is hereby reduced still further.
In order to reduce if possible the danger of unnoticed penetration of the pattern still
further, the pattern of electrically conducting members on the one side of the carrier is
preferably shifted by at least one width relative to the pattern of electrically conducting
members on the other side of the carrier.
The patterns of electrically conducting members are thus "overlapping" on either side of
the carrier; where insulating material is situated on the one side of the carrier, a part of
the pattern of electrically conducting members is situated on the other side, and vice
versa.
In a following preferred embodiment, in order to achieve the above stated effect the
pattern of electrically conducting members on the one side of the carrier is displaced
relative to the pattern of electrically conducting members on the other side of the carrier.
The electrically conducting members advantageously comprise a conducting ink
comprising a mixture of carbon and metal powder.
The composition of such a carbon-metal powder mixture is determined as a function of
the desired resistance value of the conducting members. In an advantageous
composition an ultraviolet-sensitive resin is also added to the ink. The mixture of
carbon and metal powder in combination with the patterns of mutually overlapping
conducting members on either side of the carrier make the pattern of conducting
members invisible to X-ray examination. It is thus precluded that the orientation of the
pattern can be determined using advanced means and manipulations made possible. It
will be apparent that this provides an exceptional advantage.
In order to enhance the above stated effect still further, as well as to render impossible
visualization of the device using a microscope, in an advantageous embodiment the
security means are coated on at least one side with a light-absorbing layer.
The present invention also relates to a device for securing value goods, in particular
value documents, comprising a closable space which is enclosed by a shell, wherein the
goods for securing can be received in the space and wherein the shell is at least partially
provided with security means according to the present invention.
By providing the shell of the device, and preferably that part through which an
unauthorized person can most easily gain access to the space, with or coupling it to the
security means according to the present invention an attempted forced entry into the
secured space can be detected by registration of a resistance change.
If the secured goods must not fall into the hands of unauthorized persons, but may
optionally be replaced by authorized persons, which may for instance be the case for
value documents, it can be advantageous to at least partially destroy the goods when an
attempt at forced entry is made by an unauthorized person. To this end the registration
device in the device according to the present invention is advantageously coupled to
destruction means such that, when a determined limit resistance value is reached or
exceeded, activation of the destruction means and at least partial destruction of the
secured goods takes place.
The device according to the present invention is preferably applied for transport of value
documents, such as money, and in a preferred embodiment comprises a case.
The shell of the case preferably takes a double-walled form, while the security means
are situated between the walls. In this embodiment the security means are invisible from
the outside of the case.
The present invention will be further elucidated hereinbelow with reference to the
annexed drawing, in which:
- figure 1
- shows schematically a section of - a part of - security means
according to the prior art;
- figure 2
- shows schematically a section of - a part of - security means
according to the present invention; and
- figure 2
- shows schematically a section of a device for securing value
goods.
The figures are purely schematic and not drawn to scale. For the sake of clarity some
dimensions in particular are shown in greatly exaggerated manner. Corresponding
components are designated as far as possible in the figures with the same reference
numeral.
Figure 1 shows schematically a section of - a part of - security means 1 according to the
prior art. Such security means are intended for coupling to a shell, at least a part thereof,
of a substantially closed space. When an unauthorized person attempts to break into or
otherwise manipulate the substantially closed space provided with a security means,
detection of such an attempt can take place using the security means.
Security means 1 comprise a carrier 2 on which a pattern of electrically conducting
members 3 is arranged. The carrier normally comprises a flat sheet of carrier material. In
the shown embodiment the security means 1 are placed between two walls 5,6 of the
shell of a substantially closed space and coupled thereto using a glue connection 7.
Device 1 is moreover connected to registration means - not shown in the figure - for
registering a resistance change in conducting members 3.
The operation of security means 1 is based on a measurement of a resistance change in
conducting members 3. The carrier 2 with electrically conducting members 3 which is
coupled to shell 5,6 of the space for securing, and preferably along the surface thereof
through which an unauthorized person could possibly gain access to the secured space
by means of forced entry, has a determined resistance. When during an attempted forced
entry the shell of the secured space and therewith the pattern of electrically conducting
members is damaged or distorted, a resistance change occurs which is registered by
means of the registration means. The registration means can for instance be coupled to
an alarm system so that an alarm is immediately set into operation.
As discussed in the foregoing, the security means 1 of the prior art have a number of
drawbacks. As shown in figure 1, "openings" 8 left clear by the pattern are situated
between the pattern of electrically conducting members 3. It has been found that these
openings 8 can be penetrated in a relatively simple manner with assist means suitable
for this purpose in order to deactivate the electronic system, introduce substances having
an adverse effect on or disabling the operation of the security means or even to remove
the - valuable - goods situated in the secured space. The security means are moreover
found to respond over-sensitively and to already set off the alarm in the case of a
treatment which is somewhat rough but not consistent with an attempted forced entry.
The security means 1 according to the present invention, an embodiment of which is
shown in figure 2, does not display these drawbacks. Security means I according to the
present invention likewise comprise a carrier 2 on which a pattern of electrically
conducting members is arranged. In this case, however, the pattern of electrically
conducting members 3,4 is arranged on either side of carrier 2. Furthermore, at least the
aperture 8 (or: opening 8) between the pattern of electrically conducting members 3, and
in the embodiment shown in figure 2 also a small part of the space directly above and
below the pattern of electrically conducting members 3, is provided with insulating
material 10. In the shown embodiment the electrically conducting members 3 are
formed in a track-like pattern and cover a larger surface area than the intermediate
insulating material 10. The pattern of electrically conducting members 3 on one side of
carrier 2 is herein shifted by one width in relation to the pattern of conducting members
3 on the other side of carrier 2. This substantially precludes an unauthorized person
being able to penetrate the substantially closed space through the aperture (or openings)
between the pattern using assist means suitable for this purpose. The presence of the
insulating material 10 moreover prevents the security means responding over-sensitively
to for instance a treatment of the space for securing in which security means 1 are
applied which is somewhat rough but not consistent with an attempted forced entry.
In figure 2 the security means 1 according to the present invention are connected using
glue connections 7 to the walls 5,6 of the shell of the substantially closed space. A
connection of the security means 1 to the shell in other manner, for instance by means of
clamping, is of course also possible. The shell can take an inflexible form, although a
flexible embodiment is likewise possible. On the side of outer wall 6 the security means
are further provided with a light-absorbing layer 12, so that the chance that the security
means can be discerned from outside is if possible decreased still further.
The carrier 2 of the security means according to the present invention must be
sufficiently strong so that it neither tears nor is otherwise damaged during a movement
of the shell of the substantially closed space. The carrier must herein display some
degree of elasticity in longitudinal and transverse direction so that it ensures the
required tolerance when the electrically conducting members 3 are arranged, and does
not cause too great a resistance change as a consequence of manipulation of the shell.
Since the security means can be applied in both a flexible and inflexible shell, the
carrier must be flexible for bending and folding movements. It is also recommended that
the carrier is not hygroscopic and not very temperature-sensitive. Finally, the carrier
must adhere well to the pattern of electrically conducting members 3.
The material of carrier 2 preferably comprises polyester. Polyester sheets serving as
carrier material advantageously have a thickness of a maximum of 75 µm.
The electrically conducting members 3 are preferably formed by printing inks composed
of conducting materials which are not visible, or hardly so, using X-rays, such as a
mixture of carbon and metal powders. Using such a mixture an acceptable total
resistance value of the electrically conducting members 3 can be obtained. The printing
inks for the conductive tracks must have a good adhesion to both carrier 2 and glue
layers 7. This adhesion must be such that when the security means are pulled loose of
the adhesion surfaces the pattern of electrically conducting members is separated or at
least interrupted.
The glue layers must display a good adhesion to the applied printing inks and to the
walls of the shell.
Security means 1 are connected to registration means - not shown in the figure - for
registering a resistance change of conducting members 3. The registration means are
preferably programmed such that an alarm system will be set into operation only when a
determined limit value is exceeded. Such an alarm system can generate for instance an
auditively or visually discernible signal. Another possibility is that the registration
means are coupled to destruction means, wherein an activation of the destruction means
takes place when a determined limit resistance value is exceeded.
Use can for instance be made of the this latter option if the security means according to
the present invention is applied in a device for securing value goods in the form of a
container or case for transporting value documents such as money. A section of such a
case 14 is shown schematically in figure 3, wherein closable access from outside to the
inside of the case is situated on the side and is not shown. The shell of case 14 encloses
a space 15 in which value goods such as for instance value documents and money can
be received. The shell of case 14 is double-walled and comprises an inner wall 5 and an
outer wall 6. Situated between the two walls 5,6 are the security means 1 according to
the present invention which are coupled to the respective walls 5,6. This coupling can
be effected using a glue connection; other coupling methods obvious to the skilled
person can however likewise be applied for this purpose.
Case 14 is preferably enclosed on all sides by the security means 1, also designated an
electrode for shell security. When in such an embodiment the shell of the case is
provided along the whole surface thereof with shell security means 1, this is also termed
perimeter security of the case. Security means 1 can be arranged integrally or as one or
more separate sheets along the periphery of the space 15 for securing. Although security
means 1 are placed in the shown embodiment between the two walls 5,6 of the shell,
subject to the objective and the desired security, the security means can likewise be
arranged on the inside of inner wall 5 or on the outside of outer wall 6.
If an unauthorized person attempts to gain access to the space 15, he will come into
contact with the security means and herein bring about a resistance change, whereby the
destruction means are activated and the goods situated in the space will be at least
partially destroyed.
Although the present invention is described with reference to the above discussed
embodiments, the invention is in no way limited thereto. The application of the security
means according to the present invention is not limited to the detection and registration
of attempted forced entry or guarding against theft of secured goods, and other
applications are likewise possible. The security means can thus be used as liquid
detector or distortion detector. Other applications obvious to the skilled person are
likewise included herein.