GB2287742A - High voltage security grille - Google Patents

Abstract

A security grille for a glazed window or door comprises a first set of grille elements (2, 4, 6, 8) and a second set of grille elements (3, 5, 7, 9). The first and second sets of grille elements are electrically insulated from each other and electrically energised relative to each other. Conveniently, the first set of grille elements are at high voltage and the second set of grille elements are at earth potential. The first and second sets of grille elements are most preferably interdigitated such that alternate grille elements are at differing potentials. If an intruder breaks the glass of the door or window he contacts adjacent grille elements and receives a painful, but non-lethal, electric shock. One set can be electrically connected to a top rail and the other set can be electrically connected to a bottom rail. Insulating sockets 21 can be provided for extra strength. <IMAGE>

Description

Title - Security Grille This invention relates to a security grille.

The invention is of utility primarily in glazed windows or doors of, for example, commercial premises, shops and offices where break-ins might occur, or of gaols or the like from which attempts might be made to break out. Such glazed windows or doors will be called "glazed panels".

Glazed panels may be necessary for illumination, or for aesthetic or display purposes, for example, but they are vulnerable to breakage by thieves who wish to steal something from the window or enter premises, or by, for example, prisoners held inside a gaol who may wish to break out. An alarm system may be useful since it can indicate the breakage of the glass but it does not prevent someone who has broken the glazed panel from reaching or climbing through it. Also, it is not uncommon for thieves to force entry into premises which are protected by an alarm and to make their escape before police officers or other persons have time to respond to the alarm.

It is an object of the present invention to provide an improved security grille.

According to the invention there is provided a security grille for a glazed panel comprising a first set of grille elements and a second set of grille elements, the first and second sets of grille elements being electrically insulated from each other and being electrically energised relative to each other.

The security grille according to the invention is advantageous primarily in that, in addition to acting as a physical barrier, the sets of grille elements provide an electrical barrier. Since the grille elements of the first and second sets are electrically energised relative to each other, a thief or burglar who makes contact with them will receive an electric shock.

The grille elements are preferably energised by an energiser, which is preferably a high voltage, low power device. Preferably the voltage generated is between 5kV and 20kV. In practice, the voltage used must of course conform to relevant Health & Safety standards; current such standards specify a maximum voltage of lOkV. Most preferably, the voltage is applied in such a manner as to create short-duration DC pulses, eg at frequency of is~'.

Preferably, one set of grille elements is at the high voltage and the other set of grille elements is at earth potential.

For Health & Safety reasons, the security grille according to the invention is preferably fitted internally of the glazed panel, such that contact with the grille elements is precluded unless the glazed panel is broken. For similar reasons, alternate grille elements are preferably spaced apart sufficiently that an intruder's hand cannot become trapped between them, and the intruder thereby be subjected to multiple electric shocks.

Preferably, the second set of grille elements are interposed between, or interdigitated with, the first set of grille elements such that alternate grille elements are at different potentials.

The security grille may comprise top and bottom rails, the first set of grille elements being electrically connected to the top rail and insulated from the bottom rail, and the second set of grille elements being electrically connected to the bottom rail and insulated from the top rail.

The grille elements may be rigidly secured to both top and bottom rails, electrical insulation being provided where necessary by insulated spacers.

In a particularly preferred embodiment, the first set of grille elements are received at one of their ends within apertures or recesses in the top rail, and at their other ends are received within insulating bushings located in apertures or recesses in the bottom rail. Likewise, the second set of grille elements is received in apertures or recesses in the bottom rail and received in insulating bushings located in the top rail. When the grille is assembled and installed, the grille elements are pressed into close contact with the rails within which they are received, and electrical contact is achieved. This arrangement is particularly advantageous in that, because the grille elements are not permanently fixed to the rails, the security grille may be packaged in compact form, facilitating transport and storage prior to installation.

The grille elements may comprise tubular or solid bars of metal.

They may be linear or non-linear and may have a decorative function. The grille elements may contact the glazed panel or may be spaced from it.

The top and bottom rails may be connected to a voltage monitor which is connected to an alarm system so as to detect any intruder contacting the security grille. The alarm system may be triggered by any attempt to break the electrical connection between the energiser and the security grille. The alarm system may incorporate, or be connected to, conventional alarm system features such as a tamper alarm, audio or visual alarm indicators (such as a siren and strobe lamp), switches and an autodialler.

The alarm may be operated, and the security grille activated, by means of a keypad.

The invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of a security grille according to the invention, Figure 2 is a detail of an insulator used in the security grille of the invention, Figure 3 is a rear elevational view of a glazed panel having a security grille according to the invention, Figure 4 is a sectional view of the glazed panel shown in Figure 3, and Figure 5 illustrates a practical embodiment of a system including two glazed panels.

Referring to Figure 1 of the drawings, a security grille according to the invention is illustrated schematically. A first set of grille elements 2,4,6,8 is attached to, or mounted in, a top rail 16. A second set of parallel grille elements 3,5,7,9 is secured to, or mounted in, a bottom rail 17. The evennumbered grille elements 2,4,6,8 and the top rail 16 are electrically connected at 18 to the positive terminal of an energiser. They are insulated or separated as indicated at 19 from the lower rail 17 and the odd-numbered grille elements 3,5,7,9 which are earthed as shown.

Anyone trying to break a glazed panel and enter or reach through will contact the grille elements and, as soon as two adjacent grille elements are touched, the energiser will give the intruder a high voltage, low current electric shock in the form of short duration DC pulses.

In order to provide physical security as well as the electrical deterrent effect, the two sets of grille elements are each mounted in the top rail 16 and the bottom rail 17, but electrical separation is maintained at one end of each grille element by the use of insulators as shown in enlarged scrap view in Figure 2.

The bottom rail 17 can be seen to be a hollow square section bar having a circular hole 20 in which a circular insulating socket 21 is mounted. One of the even-numbered grille elements, for example the grille element 4, is mounted in the socket 21 so as to be physically secured to, but electrically insulated from, the bottom rail 17. Likewise, further insulating sockets 21 are used to insulate the odd-numbered grille elements, eg the grille element 5, from the top rail 16 (see Figure 3).

The ends of the grille elements which make contact with the respective rails are received within circular holes in one face of the rails, the ends of the grille elements making electrical contact with the internal faces of the rails, as at the point, for example, marked by the numeral 46.

Referring to Figures 3 and 4 of the drawings, a practical embodiment is shown in use. The same reference numerals have been used where appropriate. The bottom rail 17 is connected to the energiser earth 10 and is fixed to a sill 22 by means of screws 23 passing into the surrounding masonry.

The insulating sockets 21 can be seen in the bottom rail 17 mounting the first set 2,4,6,8 of grille elements which are electrically connected to the top rail 16. The top rail 16 itself is secured by means of a washer/insulator 24 to the lintel at the top of the window or other glazed panel. The positive connector 18 from the energiser is also shown. A sectional view in Figure 4 illustrates that the grille elements 2 etc are spaced from, and parallel to, the glass 25 of the window. However, it might be possible for the grille elements to be in contact with the window provided adequate electrical insulation could be achieved.

In the example shown, the top and bottom rails are of square section steel tube and the grille elements are of hollow steel tube of smaller circular cross-section. However, they could be solid bars or strips.

The form of energiser used in the system is similar to that used in an electrified fence for agricultural use, and is capable of producing a relatively high voltage of the order of between 5kV and 20kV but at low current. This means that although a painful shock is felt, the shock is non-lethal.

A suitable electric fence energiser may be of the type marketed by Rutland Electric Fencing Co Ltd under the designations RUTLAND ESM400, ESM600 or ESM1000. Such energisers satisfy relevant standards such as CENELEC EN61011/1 (Test Report Ref 95145). In practice, it is important that only approved units are used.

The system can be used to protect a number of glazed panels and Figure 5 illustrates the arrangement. Glazed panels 26,27 are connected in series with each other and have a common positive connector 18 electrically connected to their top rails and a common earth 10 electrically connected to their bottom rails.

The earth and live connectors make connection with a control unit 29 incorporating an energiser to generate the voltage between them.

The control unit 29 also incorporates a voltage monitor. Any contact with the grille elements which produces a voltage change will be detected by the voltage monitor. This in turn passes a signal to an alarm system, for example to operate a siren 31.

The power supply for the whole system is a mains power outlet indicated at 32. A battery back-up unit 33 is also provided.

The system can be controlled using a keypad 34 and a key switch 35.

The control unit 29 is also connected to a magnetic contact switch 36 located on a designated entry/exit door. Actuation of the contact switch 36 by a person entering through the door initiates a delay during which the alarm can be disabled using the keypad 34 or the key switch 35.

Modifications can be made to the system described. In particular, the rectilinear grille elements can be replaced by more decorative elements if the device is to be used in security of a residence or office. The number and spacing of the grille elements will be determined by the use to which the security grille is put. For example, relatively slender and inconspicuous grille elements may be required for a jeweller's shop window but these must be closely spaced together. This would prevent anyone breaking the window and reaching through between the bars to steal valuable items. However, where the security grille is only intended to prevent a person gaining access through a glazed panel, the grille elements may need to be fairly substantial bars or tubes which are spaced at a separation between bars of opposite polarity of approximately 10cm.

Claims (11)

Claims

1. A security grille for a glazed panel comprising a first set of grille elements and a second set of grille elements, the first and second sets of grille elements being electrically insulated from each other and being electrically energised relative to each other.

2. A security grille as claimed in Claim 1, wherein the grille elements are connected to, and energised by, a high voltage, low power energiser, generating a voltage of between 5kV and 20kV.

3. A security grille as claimed in Claim 2, wherein the voltage is applied in such a manner as to create short-duration DC pulses.

4. A security grille as claimed in any preceding claim, wherein one set of grille elements is at a high voltage and the other set of grille elements is at earth potential.

5. A security grille as claimed in any preceding claim, wherein the second set of grille elements are interposed between, or interdigitated with, the first set of grille elements such that alternate grille elements are at different potentials.

6. A security grille as claimed in any preceding claim, which comprises top and bottom rails, the first set of grille elements being electrically connected to the top rail and insulated from the bottom rail, and the second set of grille elements being electrically connected to the bottom rail and insulated from the top rail.

7. A security grille as claimed in Claim 6, wherein the grille elements are received within openings in the top and bottom rails, electrical insulation being provided at one end of each grille element by insulated spacers.

8. A security grille as claimed in Claim 7, wherein the first set of grille elements are received at one of their ends within openings in the top rail and at their other ends are received within insulating bushings located in apertures or recesses in the bottom rail, and the second set of grille elements are received within openings in the bottom rail and received in insulating bushings located in the top rail.

9. A security grille as claimed in any preceding claim, wherein the grille elements comprise tubular or solid bars of metal.

10. A security grille as claimed in any preceding claim, which is connected to an alarm system.

11. A security grille substantially as hereinbefore described and as illustrated in the accompanying Figures.