NZ615339B2 - Improvements in, or relating to, tamper evident systems - Google Patents
Improvements in, or relating to, tamper evident systems Download PDFInfo
- Publication number
- NZ615339B2 NZ615339B2 NZ615339A NZ61533913A NZ615339B2 NZ 615339 B2 NZ615339 B2 NZ 615339B2 NZ 615339 A NZ615339 A NZ 615339A NZ 61533913 A NZ61533913 A NZ 61533913A NZ 615339 B2 NZ615339 B2 NZ 615339B2
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- New Zealand
- Prior art keywords
- electrically conductive
- resilient deformable
- tamper
- conductive portion
- impedance
- Prior art date
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- 238000001514 detection method Methods 0.000 claims abstract description 30
- 239000000789 fastener Substances 0.000 claims description 19
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- 238000002847 impedance measurement Methods 0.000 claims description 2
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- 229910000529 magnetic ferrite Inorganic materials 0.000 description 4
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Abstract
Disclosed is a tamper detection element (9) adapted at least in part to be located against a first member to detect tampering therewith. The element (9) has a resilient deformable member (3) in a rigid housing able to deform because of the tampering and undergo tamper induced deformation. A contact sensing member (5) contained within the rigid housing is disposed towards the resilient deformable member. A first electrically conductive portion (4) sits adjacent or on the resilient deformable member (3) and a second electrically conductive portion resides on the contact sensing member (5). An electrical relationship can be formed between the first (4) and second electrically conductive portions, and the tamper induced deformation results in a change of impedance of the electrical relationship, the change therefore indicative of the tampering. sensing member (5) contained within the rigid housing is disposed towards the resilient deformable member. A first electrically conductive portion (4) sits adjacent or on the resilient deformable member (3) and a second electrically conductive portion resides on the contact sensing member (5). An electrical relationship can be formed between the first (4) and second electrically conductive portions, and the tamper induced deformation results in a change of impedance of the electrical relationship, the change therefore indicative of the tampering.
Description
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IMPROVEMENTS IN, OR RELATING TO, TAMPER EVIDENT SYSTEMS
TECHNICAL FIELD OF THE INVENTION
The present invention relates to tamper evident systems. In particular, though not solely,
the present invention is directed to tamper evident devices, their methods of use and
manufacture to detect unauthorised tampering of fasteners, or devices held in place by
fasteners.
BACKGROUND OF THE INVENTION
There is increased use of systems that are remotely monitored. These systems may only
occasionally be visited by human operators. Such systems may be remote in their
location, or may be in everyday situations, for example in households, commercial
premises, or urban or town environments.
The reasons these systems may rarely see human operators is because they may be
numerous in number and therefore the cost of regular visits may be too high, or may be
too remote to regularly visit. The systems themselves tend to be stable and will easily run
for long periods of time with no need for a human operator on site.
Such systems however, because they may be in dense population areas may be the
target of attempted theft, vandalism or other abuse which may compromise the system
itself, or at least the cabinet, components, for example key pad or similar the system and
equipment is contained in. The lack of regular human visits makes detection of such
tampering difficult.
Examples of such systems are household and commercial power meters. These can now
be easily monitored from the central control of the power company and thus there is no
need to visit such equipment to take meter readings as there has been in the past.
Moreover, there is a need to ensure such meters are not tampered with due to the cost of
such meters and also the loss of revenue if such meters do not read correctly.
There may also be systems that are regularly visited, but their equipment or content may
be mission critical (for example traffic light systems), of high value (for example currency
vending machines), or that otherwise require confidence in their integrity and security (for
example EFTPOS payment machines.
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Tamper detection is also valuable for a computer or electronics suite. For example, it may
allow an alert to occur if a person attempts to gain access to the internal units or remove
device components. Equipment that has key pads, security card readers, or credit card
and EFTPOS machine readers can often be tampered with to remove and replace the
content with the tamperer’s own equipment. This, for example, would direct funds to the
tamperer’s account instead of the correct account. Other tampering may involve insertion
of information scanning systems to allow capture of a user’s information, for example
security keypad entry, credit card or EFTPOS card details.
There is also a need for a device which can detect the loosening of, for example,
fasteners or other components relative to each other. Such loosening may occur due to
tampering, but may also occur due to general wear and tear, vibration and movement, and
the weather.
An example of a prior art solution is that found in US 6,774,807 of Lehfeldt et al. This
discloses a fastener that utilises a magnetic switch or micro-switch in the fastener or
against the fastener periphery that activates when the fastener is turned through a certain
angle. These switches are actuated by a mechanical system that must be in close
proximity to the fastener, or utilise a magnetic pickup and associated components. As
such they require extra systems and components and specially designed and shaped
fasteners.
In this specification where reference has been made to patent specifications, other
external documents, or other sources of information, this is generally for the purpose of
providing a context for discussing the features of the invention. Unless specifically stated
otherwise, reference to such external documents is not to be construed as an admission
that such documents, or such sources of information, in any jurisdiction, are prior art, or
form part of the common general knowledge in the art.
It is therefore an object of the present invention to provide an improved tamper evident
system, or to overcome the above shortcomings or address the above desiderata, or to at
least provide the public with a useful choice.
BRIEF DESCRIPTION OF THE INVENTION
In a first aspect the present invention consists in a tamper detection element adapted at
least in part to locate against a first member to detect tampering therewith, comprising or
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including:
a resilient deformable member able to deform because of said tampering (“tamper
induced deformation”);
a rigid housing to locate and substantially contain said resilient deformable member
to said first member;
a contact sensing member disposed towards said resilient deformable member and
substantially contained in said rigid housing;
a first electrically conductive portion adjacent or on said resilient deformable
member, and
a second electrically conductive portion on said contact sensing member,
wherein an electrical relationship can be formed between said first and second
electrically conductive portions, and said tamper induced deformation results in a
change of impedance of said electrical relationship, said change therefore
indicative of said tampering.
Preferably in use the resilient deformable member is held in compression.
Preferably the resilient deformable member can be removed from and reinserted into the
tamper detection element.
Preferably said second electrically conductive portion is disposed towards said first
electrically conductive portion.
Preferably there is a third electrically conductive portion on said contact sensing member
and said impedance is measured between said second and third electrically conductive
portions.
Preferably said element is located between said first member and a second member to
detect tampering as a relative movement therebetween.
Preferably said deformation occurs due to said relative movement of said first member
and said second member.
Preferably said resilient deformable member extends at least in part beyond said rigid
housing.
Preferably tampering with said rigid housing also results in said deformation.
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Preferably said impedance changes due to change in either or both a contact area, or a
pressure, between said first electrically conductive portion, and either or both of said
second and said third electrically conductive portions.
Preferably said resilient deformable member is an endless member.
Preferably said element can locate about a body of a fastener extending from said first
member, said body passing substantially through a middle of said element.
Preferably said element is adapted to be held in place against said first member by said
second member which is engaged with said first member.
Preferably said resilient deformable member is made from a resilient deformable material
such as, but not limited to any one or more of,
an elastomer, or
a rubber.
Preferably said contact sensing member is substantially formed from a printed wire board.
Preferably an electrical connection may be made from said element to a voltage or current
supply to measure said impedance and/or said variation thereof.
Preferably an impedance measurement device is externally connected to said element.
Preferably said impedance is made up of any one or more of a resistance, capacitance or
inductance.
Preferably the said first electrically conductive portion and said second electrically
conductive portion are substantially planar, at least where they are adapted to locate
between said first member and said second member.
Preferably said resilient deformable member is arranged to lie substantially co-extensive
with said contact sensing member.
Preferably an active region of said element to locate between said first member and said
second member is substantially shaped to conform to and be co-extensive with a surface
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or surfaces of said first member and or said second member that it locates between.
In a second aspect the present invention consists in a method of detecting tampering
with a first member, comprising or including the steps of:
providing a resilient deformable member able to deform because of said tampering
(“tamper induced deformation”) with said first member;
providing a rigid housing to locate and substantially contain said resilient deformable
member to said first member;
providing a contact sensing member substantially contained in said rigid housing and
disposed towards said resilient deformable member;
providing a first electrically conductive portion adjacent or on said resilient deformable
member, and
providing a second electrically conductive portion on said contact sensing member
connecting either or both said resilient deformable member and/or said contact
sensing member to said first member,
forming an electrical relationship between said first and second electrically conductive
portions;
wherein said tamper induced deformation results in a change of impedance of said
electrical relationship;
measuring said change; and
deciding whether a tamper event has occurred or not.
Preferably the resilient deformable member, in use, may be held in compression by said
first member.
Preferably the method further comprises the step of removing and reinserting the resilient
deformable member in the tamper detection element.
Preferably said decision of whether a tamper event has occurred includes the step of
determining whether said change meets or exceeds a threshold.
Preferably said method comprises the step of measuring a base reading of said
impedance.
Preferably said method comprises periodically measuring said base reading of said
impedance.
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Preferably said method comprises triggering an alert if said tamper event is detected.
Preferably said alert is triggered proximal said connection to said first member or part
thereof, or remote thereto.
Preferably there is a monitoring of a plurality of said tamper detecting elements connected
throughout a piece of equipment, to detect tampering with said equipment.
Preferably said resilient deformable member extends at least in part beyond said rigid
housing.
Preferably tampering with said rigid housing results in said deformation.
Preferably said method includes the step of monitoring said impedance to detect a tamper
event.
In a third aspect the present invention consists in equipment including one or more
tamper detecting elements to detect a tampering with at least a first member of said
equipment, said tamper detecting elements comprising;
a resilient deformable member able to deform because of said tampering (“tamper
induced deformation”);
a rigid housing to locate and substantially contain said resilient deformable member
to said first member;
a contact sensing member disposed towards said resilient deformable member and
substantially contained in said rigid housing;
a first electrically conductive portion adjacent or on said resilient deformable
member, and
a second electrically conductive portion on said contact sensing member
wherein an electrical relationship can be formed between said first and second
electrically conductive portions, and said tamper induced deformation results in a
change of impedance of said electrical relationship, said change therefore
indicating said tampering.
Preferably there is a plurality of said elements to detect tampering with said equipment.
Preferably detection of whether a tamper event has occurred includes determining
whether said change meets or exceeds a threshold.
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Preferably a base reading of said impedance is made.
Preferably said base reading of said impedance is measured.
Preferably an alert is triggered if said tamper event is detected.
Preferably said alert is triggered proximal said connection to said first member, or remote
thereto.
In a fourth aspect the present invention consists in a kit of parts for at least one tamper
detecting element, comprising or including;
a resilient deformable member able to deform because of said tampering (“tamper
induced deformation”);
a rigid housing to locate and substantially contain said resilient deformable
member to said first member;
a contact sensing member disposed towards said resilient deformable member;
said rigid housing to substantially contain said contact sensing member;
a first electrically conductive portion adjacent or on said resilient deformable member;
and
a second electrically conductive portion on said contact sensing member;
wherein an electrical relationship can be formed between said first and second electrically
conductive portions, and said tamper induced deformation results in a change of
impedance of said electrical relationship, said change therefore indicative of said
tampering.
Preferably said kit includes a fastening means for said element.
Preferably wherein said resilient deformable member extends at least in part beyond said
rigid housing.
Preferably said kit includes a plurality of said elements.
In yet still another aspect the present invention may be said to broadly consist in a tamper
detection element as herein described with reference to any one or more of the
accompanying drawings.
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In yet still another aspect the present invention may be said to broadly consist in a
method of detecting tampering as herein described with reference to any one or more
of the accompanying drawings.
In yet still another aspect the present invention may be said to broadly consist in
equipment including one or more a tamper detecting elements as herein described
with reference to any one or more of the accompanying drawings.
In yet still another aspect the present invention may be said to broadly consist in a kit of
parts for a tamper detecting element as herein described with reference to any one or
more of the accompanying drawings.
As used herein the term “and/or” means “and” or “or”, or both.
As used herein “(s)” following a noun means the plural and/or singular forms of the noun.
The term “comprising” as used in this specification means “consisting at least in part of”.
When interpreting statements in this specification which include that term, the features,
prefaced by that term in each statement, all need to be present, but other features can
also be present. Related terms such as “comprise” and “comprised” are to be interpreted
in the same manner.
It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10)
also incorporates reference to all rational numbers within that range (for example, 1, 1.1,
2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that
range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7).
The entire disclosures of all applications, patents and publications, cited above and below,
if any, are hereby incorporated by reference.
To those skilled in the art to which the invention relates, many changes in construction
and widely differing embodiments and application of the invention will suggest themselves
without departing from the scope of the invention as defined in the appended claims. The
disclosures and the descriptions herein are purely illustrative and are not intended to be in
any sense limiting.
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Other aspects of the invention may become apparent from the following description which
is given by way of example only and with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred forms of the present invention will now be described with reference to the
accompanying drawings in which;
Figure 1 shows an external isometric view of an embodiment of the tamper detecting
element mounted to a threaded member on part of a piece of equipment,
Figure 2 shows an exploded view of Figure 1,
Figure 3 (A) shows a side view of Figure 1,
Figure 3 (B) shows a cross section along line AA of Figure 3A,
Figure 4 shows Detail B from Figure 3(B),
Figure 5 close up showing pill deforming out of housing,
Figure 6 is a circuit diagram for the tamper detecting element,
Figure 7 (A) is an isometric external view of equipment with tamper detecting
element(s) located thereon,
Figure 7 (B) is an isometric internal view of Figure 7(A),
Figure 8 Shows Detail C from Figure 7(B), and
Figure 9 Shows various circuits in which the present invention uses impedance to
sense tampering, with (9A) showing a single resistive circuit across once
portion of the resilient deformable member (for example a (first) electrically
conductive portion (for example on the deformable member) onto a single pad
as a further (second) electrically conductive portion), (9B) showing a double
resistive circuit with two or more sensed resistive portions (for example a (first)
electrically conductive portion of the deformable member onto a first pad as
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the (second) electrically conductive portion and a second pad as the third
electrically conductive portion, (9C) showing a single capacitive circuit across
the resilient deformable member (for example a (first) electrically conductive
portion of the deformable member spaced by off from a single pad (for
example by a non-conductive portion of the deformable member to act as a
dielectric) as a further (second) electrically conductive portion, (9D) a dual
capacitive circuit of (9C), (9E) showing a single inductive circuit across one
side of the deformable member where the member has a ferrite or similar
core, and (9F) showing a dual inductive circuit of (9E).
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments will now be described with reference to Figures 1 through 9.
The tamper detection element 1 is shown in Figures 1 and 2 held to a first member 2 by a
second member 8. In this instance the second member 8 is comprised of a threaded
fastener 8A and a nut 8B engaged thereon. There are several ways in which the element
1 can perform its task, and in the preferred embodiment it is sandwiched between a first
member and a second member. A fastener is just one example of how it can be held in
place, other methods can also be used, such as sandwiching between a first member and
a second member which may be a planar surface such as a wall or door. For example the
fastener 8A and nut 8b in Figures 3 and 4 may not be present, but rather the second
member 8 is a surface of a cabinet or door sandwiching the element 1 in place.
The element 1 consists of a resilient deformable member 3 which when the element is
secured in place is held down against or in proximity to a contact sensing member 5. In
practice the resilient deformable member 3 is made from an elastomer such as silicon.
However, any material that is compressible and resilient will suffice, for example rubber
(natural or synthetic), or other such similar materials. In a preferred embodiment there is
present a housing 9, to at least in part contain the members 3 and 5. The element 1 relies
on change in pressure on the element to vary the impedance of the element.
The relationship between the resilient deformable member 3 and the contact sensing
member 5 will determine if a tamper is occurring. The tamper detection may comprise an
electrical circuit connected to tamper detection element 1. The electrical circuit may
measure the impedance, or its variation, of the circuit, for example of the resilient
deformable member 3 and the contact sensing members. The impedance measured may
comprise one of, or a combination of, resistive, capacitive or inductive components.
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In one embodiment as a resistive circuit the resilient deformable member 3 has a first
electrically conductive portion 4 as seen in Figure 4. This in the assembly shown is on the
lower part of the resilient deformable member 3. In an alternative embodiment the first
electrically conductive portion may be on the upper or a middle part of the resilient
deformable member, for example in use as a capacitive circuit. In some embodiments the
first electrically conductive portion may be encapsulated inside the resilient deformable
member, for example in use as an inductive circuit. In a further alternative embodiment
the first electrically conductive portion may be adjacent, and not part of the resilient
deformable member. When the first conductive portion and the resilient deformable
member are adjacent there may be an air gap (for example for capacitive sensing), spacer
or other element/s placed between them.
The first electrically conductive portion 4 may be a lower portion of the member 3 that is
conductive. The electrically conductive portion 4 may contact the contact sensing
member 5, for example on a second electrically conductive portion 6 as shown in Figure 6
or the portion and member may be separated by another element, such as an electrical
insulator (for example when capacitive or inductive sensing is used). For example when
the material is an elastomer it may be doped, for example with carbon to make that lower
portion conductive to therefore form the first conductive portion 4. When it is the lower
form and in contact with the second conductive portion 6 is may be used for resistive
sensing of tampering. When it is on the upper portion (whether unitary or separate) then it
may be part of a capacitive sensing or inductive sensing. In a further example the
material may be silicon doped with ferrite to act as, for instance, a magnetic core. IN
other forms, the deformable member 3 may act as a way to exert pressure (and therefore
vary it n tampering) and other electrical components to form the impedance circuit may be
located against it. However, there will be other methods known in the art for other
materials that may also suffice. Preferably the upper portion and remainder of the
member 3 that is not in contact with the contact sensing member 5 is not conductive. This
may insulate the circuit from the effects of any wear of the housing 9. As shown in Figure
2 the member 3 is an endless member, but can be formed as necessary to fit the desired
application.
The contact sensing member 5 is shown in Figure 2 (and Figure 6) has at least one
second electrically conductive portion 6 at the head 14. In the preferred form shown in
Figure 2 it has two such portions a second 6 and third 7 (or more) on a top surface, which
are diametrically opposed, to allow for example electrical contact with the first conductive
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portion 4 when there is resistive sensing. Alternatively the portions may be below the
surface (for example when physical electrical contact with deformable member 3 is not
required, for example in capacitive or inductive sensing). The portions may cover
substantially the whole of contact sensing member or may comprise a section or part of
the contact sensing member. The head 14 of the contact sensing member 5 typically
conforms to the shape of the resilient deformable member 3 it locates against but is not
necessarily so. Therefore in the example shown in Figure 2 the head 14 is also shown as
an endless member. However, in other embodiments the head 14 of the contact sensing
member 5 where it locates with the resilient deformable member 3 may be shaped as
needed for the intended application.
The tail 15 extends from the head 14 of the contact sensing member 5 as shown in Figure
2. The tail 15 contains circuit traces 16 which go to one each to the second electrically
conductive portion 6 and third electrically conductive portion 7. Traces 16 then connect
out and at the end of the tail 15 for connection to sensing equipment 17. The sensing
equipment can be locally contained within the piece of equipment 12 which is being
protected, and in addition may send signals locally for alerts or may send them remotely
from the piece of equipment 12. For example the sensing equipment 17 may send a local
alert for example a flashing light or otherwise, and may also or instead send a signal to a
remote sensing station to sound an alarm to indicate tampering with the equipment.
The contact sensing member or members may comprise additional electrical contacts.
The electrical contacts may be provided on a backing layer. The backing layer may
provide support or encourage the contacts into appropriate positions. In a preferred
embodiment these contacts will comprise a part of a printed wire board. The printed wire
board may be rigid, flexible or comprise both rigid and flexible sections. In the following
description it should be realised that reference to a printed wire board or other backing
layer material encompasses a broad range of backing layers, flexible, rigid or otherwise.
In one embodiment the contact sensing member 5 is a flexible printed circuit with exposed
conductive portions forming the second electrically conductive portion 6 and third
electrically conductive portion 7. Some, or all, of the areas of the flexible printed circuit
may also be reinforced. This may help to insert it into equipment and/or for mounting
purposes. In a further embodiment a rigid printed wiring board may be used, for instance
to provide a more resilient member. In a preferred embodiment the total impedance of the
circuit formed in conjunction with the first resilient deformable member 3 when in contact
with the contact sensing member 5 is within a known range and any deviation may cause
an alarm.
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In one embodiment the impedance of an immediate physical contact between a resilient
deformable member 3 having a first electrically conductive portion 4 against at least the
second electrically conductive portion 6 and preferably third electrically conductive portion
7 is within a known range, and any deviation again, may cause an alarm. In an alternative
embodiment the impedance of an electrical relationship between a first electrically
conductive portion 4 adjacent or on said resilient deformable member 3 and a second
electrically conductive portion 6 and possibly a third electrically conductive portion 7 is
within a known range, and any deviation again, may cause an alarm. In this alternative
embodiment there may not be contact between all or any of the conductive portions 4, 6,
and 7 and the capacitance or inductance between the conductive portions may be
measured.
In an alternative embodiment the total impedance of the circuit formed in conjunction with
the first resilient deformable member 3 when in contact with the contact sensing member
is within a known range and any deviation may cause an alarm. The change in the total
impedance of the circuit formed may be due to a change electrical relationship between
the members 3, 5. In a first example the capacitance between the resilient deformable
member 3 and its first electrically conductive portion 4 and at least the second electrically
conductive portion 6 and preferably third electrically conductive portion 7 is within a known
range, and any deviation again, may cause an alarm. For instance the capacitance of two
conductive areas will change if the distance or pressure between those areas or their
spatial relationship is altered. A straightforward example of this is a parallel plate
capacitor. In a further example the inductance between the resilient deformable member
3 and its first electrically conductive portion 4 and at least the second electrically
conductive portion 6 and preferably the third electrically conductive portion 7 is within a
known range, and any deviation due to a change in pressure or relative movement, may
cause an alarm. For instance, the resilient deformable member 3 may comprise a coil
and the movement of the first electrically conductive portion 4 may change the inductance
apparent to the first electrically conductive member and a second portion 6. In a further
example the resistance of a path through the electrically conductive portion 7 of the
resilient deformable member 3 and at least the second electrically conductive portion 6
and preferably the third conductive portion 7 is within a known range, and any deviation
due to a change in pressure or relative movement may cause an alarm. In a simple
example contact could be made between the conductive portions forming a small circuit
between the second and third conductive portions, alternatively this may be a capacitive
or inductive circuit as shown in Figure 9. The total measured impedance may include a
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combination of resistance, capacitance or inductance, in combination or as separate
measurements.
Figure 9 demonstrates further methods of creating measureable impedance. It will be
clear to the reader that these are only example methods and may be combined or
alternative methods may be used. Looking first at Figure 9a, a measurement may be of
the resistance between a first electrically conductive portion 4 (which in the preferred
embodiment is part of the deformable member 3), adjacent to the resilient deformable
member 3, in physical contact with a second electrically conductive portion 6 below the
member. In an alternative resistive embodiment (figure 9b) a third electrically conductive
portion 7 may be present on the contact sensing member, or elsewhere. This portion may
allow a circuit to be formed between the first, second and third contact members for
sensing. In some embodiments the first conductive portion may be on (part of) the resilient
deformable member 3.
Figures 9c and 9d demonstrate alternative embodiments which may measure capacitive
impedance. Figure 9c shows a first electrically conductive member 4 and a second
electrically conductive member 6 separated by a (or part of a) resilient deformable
member 3. In this embodiment the member 3 acts as a dielectric between the two
conductive portions and movement of the resilient deformable member will result in a
change in the level of capacitance of the electrical relationship between the portions. In
figure 9d a further embodiment is shown where a third electrically conductive portion 7 is
present, located on the contact sensing member 6. In this embodiment the first
electrically conductive portion 4 may be adjacent to the resilient deformable member 3 –
placed directly above or separated by an air-gap or intermediate layer – or the first
electrically conductive portion 4 may be on (part of or encapsulated by) the resilient
deformable member 3.
Figures 9e and 9f demonstrate further alternative embodiments which may measure
inductive impedance. Figure 9e shows a system in which first 4 and second 6 electrically
conductive members may be coils or loops. The resilient deformable member 3 may
comprise a silicon doped ferrite core to increase the effect of any tamper induced
deformation, or may be separate thereto, and simply hold the core proximate the coils.
Tamper induced deformation may be measured by the change in inductance between the
conductive portions. In alternative embodiments the conductive members may be wound
around areas of the tamper detection element as would be known by one skilled in the art.
Figure 9f shows a further embodiment where both the first 4 and second 6 electrically
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conductive portions are located on the contact sensing member. The resilient deformable
member 3 may be doped with ferrite (or support a separate core) so as to provide a
magnetically permeable core to improve coupling between the conductive portions.
Other circuit traces may also be present in the printed wire board for redundancy or other
purposes.
The tamper detection element 1 also has a housing 9. The housing may be designed to
contain the contact sensing member and the resilient deformable member and ensure
appropriate contact and positioning between them. It can also serve to protect the
members 3 and 5 to prevent tampering with them. In a preferred embodiment shown in
Figure 4 the housing is hollowed out in the direction towards the resilient deformable
member 3 and contact sensing member 5 to at least receive the head 14 of the contact
sensing member 5 and a substantial part of the resilient deformable member 3. In a
preferred form of the housing 9 there is a small aperture 18 in a side wall to allow the tail
to be passed there through and may also be an internal relief to help retain at least the
head 14 of the contact sensing member 5. The housing 9 may also have one or more
engaging features 19 to provide engagement and holding with a tool (not shown). For
example in Figure 2 the engaging features 19 are flat as shown on a side wall and
opposing side wall of the housing 9 for holding by pliers or a spanner or similar tool. In a
second preferred embodiment board the housing may be substantially larger than the
contact sensing member 5. The additional space in the housing may contain a printed
wire board. The printed wire board may comprise further security features and/or may
comprise an interface between the contact sensing member 5 and the tail 15. The printed
wire board may be shaped to fit in a hollow region of the housing. The shape of the
housing may provide means to easily remove or attach the device. In this embodiment
the tail 15 may be detachable from the housing, in some cases allowing easier installation.
As in the previous embodiment the housing may be hollowed out in the direction towards
the resilient deformable member 3, allowing contact or close proximity between resilient
deformable member 3 and the contact sensing member 5.
The housing 9 is preferable made from a resilient material. This material may be similar
to that used for the second member 8, in the embodiment shown this may be stainless
steel or a similar metal. In a preferred embodiment the material may be a resilient plastic,
for example the plastic may be PVC. As shown in Figure 2 the housing 9 is an endless
member and is contoured to conform with those parts of the conduct sensing member 5
and resilient to formable member 3 which reside therein. However, in other embodiments
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the housing 9 could be shaped as desired for the applicable installation. In a particular
embodiment the housing may appear substantially rectangular. The rectangle may have
rounded corners to contour to a second member 8 it is attached to. The end of the
rectangle distal from the second member 8 may have substantially sharp corners and may
comprise the tail 15, or the attachment means for the tail 15.
An embodiment of the assembly of the tamper detection element 1 is shown in Figures
3a, 3b and 4. In the assembly shown there is a first member 2 to which the tamper
detection element 1 is attached. In the assembly shown the second member is a
threaded fastener 8a together with a nut 8b thereon. In assembling the contact sensing
member 5 is assembled with the housing 9 (though typically this will be preassembled and
come as a sub assembly) together with the resilient deformable member 3. Again the
resiliently deformable member may already be held captive in the housing or maybe
assembled with it as required. The tamper detection element 1 is then located in the
example shown over the threaded fastener 8a and if necessary if not assembled
beforehand the resiliently deformable member 3 is then located there over and into the
appropriate cavity in the housing 9. The securing nut 8b is done up over the thread
fastener 8a to lock the assembled tamper detection element 1 in place. As can be seen in
Figure 4 the resiliently deformable member 3 is squashed between the second member 8
(in this case the threaded fastener 8a and nut 8b) and the contact sensing member 5.
Shown in Figure 4 also is the first electrically conductive portion 4 of the resilient
deformable member 3. As can be seen the first electrically conductive portion 4 is held
against the second electrically conductive portion 6 and in the preferred embodiment the
third electrically conductive portion 7. When a voltage or current is applied to the second
electrically conductive portion 6 a circuit is formed across to the third electrically
conductive portion 7 via the first electrically conductive portion 4. In some cases an AC
current or voltage may be used. The degree of pressure of the first electrically conductive
portion 4 will vary the impedance between the second and third electrically conductive
portions 6 and 7 respectively. This effect, caused by the tamper induced deformation of
the resilient deformable member 3 may be enhanced by appropriate selection of the
resilient deformable member 3 material. Therefore once the tamper detection element 1 is
assembled a base reading can be taken and thereafter variance in this base reading, for
example the total impedance of the circuit, outside of certain thresholds will indicate that
tampering is occurring, for example the distance between the first member 2 and second
member 8 is changing. For example an unauthorised user may be undoing the nut at 8b
which will then reduce the pressure of the resilient deformable member 3 against the
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contact sensing member 5 thus resulting in an increased impedance of this circuit. Once
this exceeds the threshold value then an alarm or tampering event will be triggered. In
other embodiments less preferable the circuit may be formed and measured between the
first electrically conductive portion 4 and the second electrically conductive portion 6 only.
In an alternative embodiment there may not be direct contact between the first electrically
conductive portion 4 and the second electrically conductive portion 6. In this case a
capacitance may be measured and the pressure between the resilient deformable
member and the contact sensing member 5 will alter the relationship between the
members and the impedance will change.
Further should the housing 9 be tampered with, for example drilling in from the side or
similar attempt at removal or tampering with the circuit the resilient deformable member 3
will “ooze” out the hole that is formed and reduce the pressure of the portion 4 against, or
proximate the portion or portions 6 and 7 and therefore again vary the impedance of the
circuit. The resilient deformable member is adapted to allow this tamper induced
deformation. In some embodiments the material used for the resilient deformable
member may be selected to enhance characteristics of the tamper induced deformation.
This is shown in Figure 5, where part of the housing 9A has been broken away. This
again will once a threshold is exceeded result in an alarm or tamper alert.
In the embodiment shown the first member 2 is a mounting plate and this for example
could be the plate of a piece of equipment through which the second member 8b as a
threaded member is passed there through to hold for example a further piece of
equipment against the first member 2 and when an attempt is made to remove or alter any
of the pieces of equipment by tampering with the tamper detection element 1 an alarm will
result. For example any attempt to create relative movement between the first member 2
and second member 8 (or elements 8a or 8b) will result in a reduced or varied impedance
of the circuit and again once the threshold is exceeded an alarm will sound.
The tamper detection element may be connected to a separate measurement device,
preferably through a connecting wire or cable. The tail 15 is preferably a flat cable and
may contain further traces or security devices. In a preferred embodiment this is a flat
USB cable. Figure 6 shows an embodiment of this connection using a 5 wire cable. In
this embodiment separate electrical connection is made to each of the electrically
conductive portions 6 and 7. In an alternative embodiment a single electrical connection
may be used, particularly if measuring the impedance or capacitance. In an alternative
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embodiment further electrical connections may be used or further tracks may be present
on the tail or measuring device for signal noise reduction or security means.
Such an assembly is shown in Figures 7a, b and Figure 8 where a piece of equipment 12
in this case a security key pad is held to a plate or first member 2 via a threaded fastener
as the second member 8. Any attempt for example to undo the security nut 8b will result
in a varied impedance of the circuit and sound an alarm. In Figure 8 the tail 15 on the
contact sensing member 5 can be seen and in this case it is loomed into the internal parts
of the piece of equipment 12. In other embodiments the tamper detection element 1 may
locate between a first member 2 and second member 8 for example as two plates or
portions of a cabinet and when relative movement between the two portions occurs
pressure is increased or decreased on the tamper detection element and therefore the
resulting impedance in the circuit will vary. In this application the tamper detection
element 1 may be in cased or packaged to retain all parts therein and may have some
form of adhesive mounting or similar to mount it to one of the two members 2 or 8 and
again a base reading taken when the two members are at the correct relationship with
each other.
The equipment 12 to be protected may be assembled with the tamper detection elements
1 as part of its assembly process or the tamper detection elements 1 may be retrofitted to
the equipment 12 either on site or as part of the maintenance of the equipment 12.
In the preferred use of the present invention there is a plurality of detection element and
these may be arrayed throughout the equipment 12 being protected. The invention may
also consist of the kit of parts to provide one or more tamper detections elements for
example to supply of equipment 12 assemblers or maintainers for pre or post fitting
thereto.
The foregoing description of the invention includes preferred forms thereof. Modifications
may be made thereto without departing from the scope of the invention.
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WHAT WE
Claims (40)
1. A tamper detection element adapted at least in part to locate against a first member to detect tampering therewith, comprising or including: 5 a resilient deformable member able to deform because of said tampering (“tamper induced deformation”), a rigid housing to locate and substantially contain said resilient deformable member to said first member; a contact sensing member disposed towards said resilient deformable 10 member and substantially contained in said rigid housing; a first electrically conductive portion adjacent or on said resilient deformable member, and a second electrically conductive portion on said contact sensing member, wherein an electrical relationship can be formed between said first and second 15 electrically conductive portions, and said tamper induced deformation results in a change of impedance of said electrical relationship, said change therefore indicative of said tampering.
2. An element as claimed in claim 1 wherein in use the resilient deformable member 20 is held in compression.
3. An element as claimed in either one of claims 1 or 2 wherein the resilient deformable member can be removed from and reinserted into the tamper detection element.
4. An element as claimed in any one of claims 1 to 3 wherein said second electrically conductive portion is disposed towards said first electrically conductive portion.
5. An element as claimed in any one of claims 1 to 4 wherein a third electrically 30 conductive portion on said contact sensing member and said impedance is measured between said second and third electrically conductive portions.
6. An element as claimed in any one of claims 1 to 5 wherein said element is located between said first member and a second member to detect tampering as a relative 35 movement therebetween.
7. An element as claimed in claim 6 wherein said deformation occurs due to said 303694476 509033NZPR relative movement of said first member and said second member.
8. An element as claimed in any one of claims 1 to 7 wherein said resilient deformable member extends at least in part beyond said rigid housing.
9. An element as claimed in claim 8 wherein tampering with said rigid housing also results in said deformation.
10. An element as claimed in any one of claims 1 to 8, when dependent on claim 5, 10 wherein said impedance changes due to change in either or both a contact area, or a pressure, between said first electrically conductive portion, and either or both of said second and said third electrically conductive portions.
11. An element as claimed in any one of claims 1 to 10 wherein said resilient 15 deformable member is an endless member.
12. An element as claimed in any one of claims 1 to 11 wherein said element can locate about a body of a fastener extending from said first member, said body passing substantially through a middle of said element.
13. An element as claimed in any one of claims 1 to 11, when dependent on claim 6, which is adapted to be held in place against said first member by said second member which is engaged with said first member. 25
14. An element as claimed in any one of claims 1 to 13 wherein said resilient deformable member is made from a resilient deformable material such as, but not limited to, any one or more of an elastomer, or a rubber.
15. An element as claimed in any one of claims 1 to 14 wherein said contact sensing 30 member is substantially formed from a printed wire board.
16. An element as claimed in any one of claims 1 to 15 wherein an electrical connection may be made from said element to a voltage or current supply to measure said impedance and/or said variation thereof.
17. An element as claimed in any one of claims 1 to 16 wherein an impedance measurement device is externally connected to said element. 303694476 509033NZPR
18. An element as claimed in any one of claims 1 to 17 wherein said impedance is made up of any one or more of a resistance, capacitance or inductance. 5
19. An element as claimed in any one of claims 1 to 18 wherein the said first electrically conductive portion and said second electrically conductive portion are substantially planar, at least where they are adapted to locate between said first member and said second member. 10
20. An element as claimed in any one of claims 1 to 19 wherein said resilient deformable member is arranged to lie substantially co-extensive with said contact sensing member.
21. An element as claimed in any one of claims 1 to 20 wherein an active region of 15 said element to locate between said first member and said second member is substantially shaped to conform to and be co-extensive with a surface or surfaces of said first member and or said second member that it locates between.
22. A method of detecting tampering with a first member, comprising or including 20 the steps of: providing a resilient deformable member able to deform because of said tampering (“tamper induced deformation”) with said first member; providing a rigid housing to locate and substantially contain said resilient deformable member to said first member; 25 providing a contact sensing member substantially contained in said rigid housing and disposed towards said resilient deformable member; providing a first electrically conductive portion adjacent or on said resilient deformable member, and providing a second electrically conductive portion on said contact sensing 30 member connecting either or both said resilient deformable member and/or said contact sensing member to said first member, forming an electrical relationship between said first and second electrically conductive portions; 35 wherein said tamper induced deformation results in a change of impedance of said electrical relationship; measuring said change; and 303694476 509033NZPR deciding whether a tamper event has occurred or not.
23. A method as claimed in claim 22 wherein the resilient deformable member is, in use, held in compression by said first member.
24. A method as claimed in either one of claims 22 or 23 further comprising the step of removing and reinserting the resilient deformable member in the tamper detection element. 10
25. A method as claimed in any one of claims 22 to 24 wherein said decision of whether a tamper event has occurred includes the step of determining whether said change meets or exceeds a threshold.
26. A method as claimed in any one of claims 22 to 25 wherein said method 15 comprises the step of measuring a base reading of said impedance.
27. A method as claimed in claim 26 wherein said method comprises periodically measuring said base reading of said impedance. 20
28. A method as claimed in any one of claims 20 to 27 wherein said method comprises triggering an alert if said tamper event is detected.
29. A method as claimed in claim 28 wherein said alert is triggered proximal said connection to said first member or part thereof, or remote thereto.
30. A method as claimed in any one of claims 20 to 29 comprising monitoring a plurality of said tamper detecting elements connected throughout a piece of equipment, to detect tampering with said equipment. 30
31. A method as claimed in any one of claims 22 to 30 wherein said resilient deformable member extends at least in part beyond said rigid housing.
32. A method as claimed in any one of claims 22 to 31 wherein tampering with said rigid housing results in said deformation.
33. A method as claimed in any one of claims 22 to 32 wherein said method includes the step of monitoring said impedance to detect a tamper event. 303694476 509033NZPR
34. Equipment including one or more tamper detecting elements to detect a tampering with at least a first member of said equipment, said tamper detecting elements comprising; 5 a resilient deformable member able to deform because of said tampering (“tamper induced deformation”); a rigid housing to locate and substantially contain said resilient deformable member to said first member; a contact sensing member disposed towards said resilient deformable 10 member and substantially contained in said rigid housing; a first electrically conductive portion adjacent or on said resilient deformable member, and a second electrically conductive portion on said contact sensing member wherein an electrical relationship can be formed between said first and 15 second electrically conductive portions, and said tamper induced deformation results in a change of impedance of said electrical relationship, said change therefore indicating said tampering.
35. Equipment as claimed in claim 34 wherein there is a plurality of said elements to 20 detect tampering with said equipment.
36. Equipment as claimed in either of claims 34 or 35 wherein detection of whether a tamper event has occurred includes determining whether said change meets or exceeds a threshold.
37. Equipment as claimed in any one of claims 34 to 36 wherein a base reading of said impedance is made.
38. Equipment as claimed in claim 37 wherein said base reading of said impedance is 30 measured.
39. Equipment as claimed in any one of claims 34 to 38 wherein an alert is triggered if said tamper event is detected. 35
40. Equipment as claimed in claim 39 wherein said alert is triggered proximal said connection to said first member, or remote thereto.
Publications (1)
Publication Number | Publication Date |
---|---|
NZ615339B2 true NZ615339B2 (en) | 2015-03-25 |
Family
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