WO2006081591A1

WO2006081591A1 - Security system

Info

Publication number: WO2006081591A1
Application number: PCT/ZA2005/000076
Authority: WO
Inventors: Attila Aranyosi; Rudolph Petrus Mouton
Original assignee: Automated Identification Technologies (Pty) Ltd.
Priority date: 2005-01-26
Filing date: 2005-05-25
Publication date: 2006-08-03

Abstract

This invention provides for a security system which includes at least one portion of a fence (10) having an upper part (14) and a lower part (16) when in an operative condition. The system then further includes energizing means (12) for energizing the upper part (14) to a predetermined voltage level in the operative condition, a sensor (18) for automatically sensing tampering with the lower part (16), and a switch (20) for automatically connecting the energizing means (12) to the lower part (16) if the sensor (18) senses tampering with the lower portion (16).

Description

SECURITY SYSTEM

FIELD OF THE INVENTION

This invention relates to a security system.

BACKGROUND TO THE INVENTION

Electrical fences are known. A problem associated with existing electrical fences is that the electrification of parts of the fence below a certain height above ground level is generally not allowed by legislation due to the hazards it presents to unsuspecting people and/or animals. For this reason, only the top parts of fences are electrified. This has resulted in would-be criminals cutting and/or bending a lower part of a fence which is not electrified in order to bypass the electrified part at the top.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided a security system which includes at least a portion of a fence having an upper part and a lower part when in an operative condition, wherein said upper and lower parts include electrically conductive paths, and which upper and lower parts are electrically isolated from each other; energizing means for energizing the electrical conductive path of the upper part to a predetermined voltage level in the operative condition; a sensor for automatically sensing tampering with the lower part; and a switch for automatically connecting the energizing means to the electrical conductive path of the lower part to energize the lower part if the sensor senses tampering with the lower part.

It is to be appreciated that, by only energizing the lower part of the fence once tampering has been sensed, the danger of electrical shock to unsuspecting and innocent people or animals is prevented should they come into contact with the lower part. It is further to be appreciated that the upper part is generally of such a height to be out of general reach of people and/or animals, e.g. a certain height above ground level, or the like.

The fence may include a palisade fence. It is to be appreciated that palisade fencing is typically formed from unyielding bars arranged substantially upright to form a barrier or similar impediment. The bars may be placed in any orientation to form a barrier, e.g. upright, crosswise, and/or the like. The bars may include any cross- section. The bars may be solid or hollow.

It is further to be appreciated that palisade fencing typically further includes substantially horizontal members for supporting the bars by the members being arranged in connection with larger supporting pillars made from metal, concrete, wood, or the like. As such, the substantially horizontal members may be manufactured from any suitable material, e.g. metal, concrete, wood, and/or the like.

The electrical conductive paths of the upper and lower parts may be formed by the parts themselves, i.e. the parts may be manufactured from electrically conductive material, e.g. metal. Otherwise, the parts may include the conductive paths together with non-conductive materials for barrier purposes, e.g. wood or concrete bars with metal wiring partially embedded therein, or the like.

The fence may include a wire fence, or the like. It is to be appreciated that the fence may include any suitable fence which is able to be electrified, e.g. a wooden palisade fence having electrically conductive paths included therewith, or the like.

The energizing means may include an electrical power source for supplying voltage and current to the system. The energizing means may include a conventional energizer for an electric fence, e.g. for energizing a conductor to 10 000 V with non-lethal current levels, or the like.

The upper and lower parts of the fence may be electrically isolated from each other by being separated by an air gap. Accordingly, a span of the air gap may be calculated according to a voltage potential difference between the parts to prevent electrical arcing between said parts, e.g. a span of 50mm is used to prevent arcing between the parts having a potential difference of 10 000V, or the like. The sensor may include an electrical circuit which is configured to sense an interruption in the electrical path of the lower part. The sensor may include a strain gauge for sensing deformation of the lower part, e.g. a pole of a palisade fence being bent, or the like. It is to be appreciated that the strain gauge typically only senses substantial deformation, such as bending of a pole, or the like. It is also to be appreciated that the sensor may include any type of sensor able to detect tampering with the lower part.

The switch may include an electromechanical switch, e.g. a relay, or the like. The switch may include a solid state device, e.g. a transistor switch, or the like.

The sensor may be configured to sense a particular position of the fence which is tampered with. Accordingly, the switch may be configured to only connect a section of the fence including the sensed particular position being tampered with to the energizing means.

The system may further include an alarm which is activated when the sensor senses tampering with the lower part. The alarm may include an audio alarm. The alarm may include a visual alarm, e.g. a flashing light, or the like.

The system may include a transmitter for transmitting an alarm signal to a remote receiver when the sensor senses tampering with the lower portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of non-limiting example, with reference to the accompanying drawings wherein

Figure 1 shows, in perspective view, a security system, in accordance with the invention; and

Figure 2 shows, in diagrammatic view, a circuit diagram for one embodiment of the security system. DETAILED DESCRIPTION OF THE INVENTION

With reference to the accompanying drawings, a security system including at least a portion of a fence, in accordance with the invention, is generally indicated by reference numeral 10.

The security system includes at least a portion of a fence 10 having an upper part 14 and a lower part 16 when in an operative condition, i.e. when the fence portion is erected. In the embodiment shown, the upper and lower parts 14 and 16, respectively, define electrically conductive paths by the components being manufactured from electrically conductive metal. In addition, the upper and lower parts 14 and 16 are electrically isolated from each other.

The system also includes energizing means 12 for energizing the electrical conductive path of the upper part 14 to a predetermined voltage level in the operative condition.

The system also includes a sensor 18 for automatically sensing tampering with the lower part 16 of the fence portion 10.

Also included in the system is a switch 20 for automatically connecting the energizing means 12 to the electrical conductive path of the lower part 16 of the fence portion in order to energize the lower part 16 if the sensor 18 senses tampering with the lower part 16.

It is to be appreciated that, by only energizing the lower part 16 of the fence 10 once tampering has been sensed, the danger of electrical shock to unsuspecting and innocent people or animals is prevented should they innocently come into contact with the lower part 16. It is further to be appreciated that the upper part 16 is generally of such a height to be out of general reach of people and/or animals, e.g. a certain height above ground level, or the like. Accordingly, international legislation typically advocates a height below which a fence is not allowed to be electrified for safety reasons. For example, any portion of a fence which is in general and easy reach of people or animals which is able to come into contact with that specific portion is typically not allowed to be electrified. Only portions of a fence which must be touched to climb over the fence is generally electrified. Accordingly, only a potential intruder is in danger of electrical shock if he/she tampers with the lower part 16 of the fence 10.

As such, in a preferred embodiment, the fence 10 includes metal palisade fencing. Palisade fencing is generally comprised of unyielding bars arranged to form a barrier. Figure 1 shows a portion of a palisade fence. It is also to be appreciated that the bars are separated by a distance calculated to prevent a person and/or animal from passing between them.

Otherwise, in other embodiments, the fence 10 may include wire fencing

(not shown), or the like. It is to be appreciated that the fence 10 may include any suitable fence which is able to be electrified, e.g. a wooden fence having electrically conductive portions, or the like. Accordingly, this invention is not limited to certain types of fencing, but a in a preferred embodiment the fencing is typically palisade fencing.

Accordingly, in the embodiment shown, the electrical conductive paths of the upper and lower parts 14 and 16 are formed by the parts 14 and 16 themselves, i.e. the parts 14 and 16 are manufactured from electrically conductive material, e.g. metal, or the like. Otherwise, in other embodiments, the parts 14 and 16 may include non- conductive material together with the electrical conductive paths for barrier purposes e.g. concrete palisade fencing with metal wiring attached thereto, or metal strips imbedded in concrete palisade fencing, or the like.

The upper and lower parts 14 and 16 of the fence are further electrically isolated from each other by being separated by an air gap in the embodiment shown. The span of the air gap is generally calculated to prevent electrical arcing between the upper and lower parts 14 and 16 which may result from the high voltage level on the upper part 14 and the neutral lower part 16. In a preferred embodiment, the span of the air gap is 50mm. It is to be appreciated that the span is calculated to include a safety factor, as a 50mm air gap is the arcing distance for a voltage level of 30 000V. The energizing means 12 includes an electrical power source for supplying voltage and current to the upper and lower parts 14 and 16. In the embodiment shown, the energizing means 12 includes a transformer 12.1 and a conventional energizer 12.2 for an electric fence, e.g. for energizing a conductor to 10 000 V with non-lethal current levels, or the like. The energizing means receives electrical power from a standard 240V mains grid connection.

In a preferred embodiment of the invention, the sensor 18 for sensing tampering with the lower part is configured to sense an interruption in the electrical path of the lower part 16, e.g. when the fence has been cut, or the like. In other embodiments, the sensor 18 may include a strain gauge for sensing deformation of a part of the lower part 16, e.g. bending of a pole of a palisade fence, or the like. It is to be appreciated that the strain gauge is typically only used in a fence which is not easily deformable, e.g. palisade fencing, or the like, due to the hazard which exists that a wire fence is easily deformable.

The switch 20 is for connecting the electrical path of the lower part 16 to the energizing means 12 in order to energize the lower part 16 to the predetermined voltage if the sensor 18 senses tampering with the lower part 16. In one embodiment of the invention, the switch 20 is an electromechanical switch, e.g. a servo relay, or the like. In other embodiments, the switch 20 can be a solid state electronic device, or the like.

Figure 2 shows a diagram for the system. In this embodiment, the switch 20 includes an electro-mechanical servo which includes a plurality of contacts. A servo motor 20.2 is configured to bridge the relevant contacts upon being energized by control circuitry 20.1. The control circuitry 20.1 is, in turn, activated by the sensor 18.

It is to be appreciated that, in one embodiment, the sensor 18 is configured to sense a specific position of the fence which is being tampered with. Accordingly, the switch 20 is then configured to only connect that specific section of the fence being tampered with to the energizing means 12.

For example, the embodiment shown in Figure 1 is a single fence portion 10 comprised of two concrete pillars supporting the plurality of metal bars. Accordingly, a fence or barrier constructed from a plurality of such portions 10 may have a sensor 18 configured to sense a specific portion being tampered with. As such, the switch then only energizes that specific lower portion, and not the entire fence or barrier.

The system may further include an alarm (not shown) which is activated when the sensor 18 senses tampering with the lower part 16. The alarm may include an audio alarm. The alarm may include a visual alarm, e.g. a flashing light, or the like. Furthermore, the sensor 18 may be connected to other types of monitoring equipment (not shown) which can transmit a signal to a security company when tampering is sensed, or the like.

The system may also include a transmitter for transmitting an alarm signal to a remote receiver when the sensor 18 senses tampering.

It is to be appreciated that the switch 20 may include a predetermined delay before connecting the lower part 16 to the energizing means 12 when the sensor 18 detects tampering with the lower part 16. This delay is to prevent an innocent person accidentally bumping into a fence, or the like, from being subjected to electrical shock.

It is to be appreciated that the fence portion 10 is usable to construct any type of barrier or enclosure. Accordingly, the energizing means 12 and sensor 18 may be configured to extend their respective functions to the entire barrier and not just a single portion 10, e.g. the energizing means 12 can energize an entire fence, or the like.

It shall be understood that the examples are provided for illustrating the invention further and to assist a person skilled in the art with understanding the invention and is not meant to be construed as unduly limiting the reasonable scope of the invention.

The Inventor regards it as an advantage that the invention is able to energize a fence portion once tampering with the fence is detected in order to deter a person from tampering with the fence.

Claims

1. A security system which includes at least a portion of a fence having an upper part and a lower part when in an operative condition, wherein said upper and lower parts include electrically conductive paths, and which upper and lower parts are electrically isolated from each other; energizing means for energizing the electrical conductive path of the upper part to a predetermined voltage level in the operative condition; a sensor for automatically sensing tampering with the lower part; and a switch for automatically connecting the energizing means to the electrical conductive path of the lower part to energize the lower part if the sensor senses tampering with the lower part.

2. A system as claimed in claim 1 , wherein the fence includes a palisade fence.

3. A system as claimed in claim 1 , wherein the fence includes a wire fence.

4. A system as claimed in any one of claims 1 to 3, wherein the electrical conductive paths of the upper and lower parts are formed by the parts themselves.

5. A system as claimed in any one of claims 1 to 3, wherein the parts include the conductive paths together with non-conductive materials for barrier purposes.

6. A system as claimed in any one of claims 1 to 5, wherein the energizing means includes an electrical power source for supplying voltage and current to the system.

7. A system as claimed in any one of claims 1 to 6, wherein the upper and lower parts of the fence are electrically isolated from each other by being separated with an air gap.

8. A system as claimed in claim 7, wherein a span of the air gap is calculated according to a voltage potential difference between the upper and lower parts to prevent electrical arcing between said parts.

9. A system as claimed in any one of claims 1 to 8, wherein the sensor includes an electrical circuit which is configured to sense an interruption in the electrical path of the lower part.

5

10. A system as claimed in any one of claims 1 to 8, wherein the sensor includes a strain gauge for sensing deformation of the lower part.

11. A system as claimed in any one of claims 1 to 10, wherein the switch I O includes an electromechanical switch.

12. A system as claimed in any one of claims 1 to 10, wherein the switch includes a solid state device.

15 13. A system as claimed in any one of claims 1 to 12, wherein the sensor is configured to sense a particular position of the fence which is tampered with.

14. A system as claimed in claim 13, wherein the switch is configured to only connect a section of the fence including the sensed particular position being tampered 0 with to the energizing means.

15. A system as claimed in any one of claims 1 to 14, which includes an alarm which is activated when the sensor senses tampering with the lower part.

5 16. A system as claimed in claim 15, wherein the alarm includes an audio alarm.

17. A system as claimed in either one of claims 15 or 16, wherein the alarm includes a visual alarm. 0

18. A system as claimed in any one of claims 1 to 17, which includes a transmitter for transmitting an alarm signal to a remote receiver when the sensor senses tampering with the lower portion.

19. A system as claimed in claim 1 , substantially as herein described and illustrated.

20. A new system substantially as herein described.