GB2229564A - Security blind - Google Patents

Abstract

A security blind for a doorway or window aperture comprises two superimposed layers of synthetic polymeric material, at least one continuous electric wire 11 sandwiched between the layers and forming a non-linear path between a pair of electric contacts 14, 16 spaced apart in the region of one or more edges of the blind, further electric contacts adapted for mounting on a door frame or window frame adjacent to the blind for disconnectable electrical connection to the contacts on the blind, a power supply to the frame-mounted contacts, and detector means for producing an electrical signal upon interruption of the electric circuit including the contacts and the wire. The blind may be a roller blind or a rigid, semi-rigid or flexible screen. <IMAGE>

Description

Security Blind The present invention is a security blind, intended to deter or impede unauthorised access through a doorway or window aperture or to warn of an attempt at such unauthorised access.

A number of different types of blind are already available for preventing or detecting entry into buildings through doors and windows but existing blinds suffer from a variety of disadvantages or are impractical for domestic use. Fbr example, the heavy metal roller shutters which may be used to secure shop premises at night are clearly unsuitable for application to a house door or window, while the mental lattice blinds often used by jewellers are not only relatively expensive for the householder but are visually unattractive for non-commerical premises.Normal Venetian blinds as such represent a potential physical barrier to a casual intruder and their effect may be enhanced by the provision of a motion-sensor or noisebdetesbor but an experienced potential intruder may be able to disarm or otherwise overcome an obstruction of this type. A modified roller blind may be provided with one or more magnetic detectors but may possibly be penetrated by simply cutting the fabric of the blind.

With the disadvantages of such prior blinds in mind, it is an object of the present invention to provide a security blind which is suitable for use to protect a doorway or window aperture, especially one in a domestic location, but which is adapted in many of its forms to provide an improved measure of security as compared with many prior blinds.

The security blind according to the present invention comprises two superimposed layers of synthetic polymeric material, at least one continuous electric wire sandwiched between said layers and forming a non-linear path between a pair of electric contacts spaced apart in the region of one or mDre edges of the blind, further electric contacts adapted for mounting on a door frame or window frame adjacent to the blind for disconnectable electrical connection to the contacts on the blind, a power supply to said frame-mounted contacts, and detector means for producing an electrical signal upon interruption of the electric circuit including said contacts and said wire.Thus the signal may indicate any unauthorised activity which disturbs the blind sufficiently to disconnect a contact on the blind from an adjacent frame-mounted contact or which, in penetrating the blind itself, seers the wire sandwiched therein.

The blind according to the invention may be in the form of a flexible roller blind or may be a rigid, semi-rigid or flexible screen for extending across the doorway or window opening. For example it may be a folding screen ocoprising two or nrxe panels hinged together.

The material of the blind may take the form of one or mDre continuous unbroken sheets but may alternatively comprise one or more open lattices, designed to cover the whole area of the doorway or window but to allow a high proportion of the incident light to pass through it and/or to afford a minimal obstruction to the view through it. The material of the layers of which the blind is formed is a synthetic polymeric material, among ' & ich materials polyvinyl chloride (PVC) is preferred, and it is most preferably a non-transparent material, so that the wire sandwiched therein cannot be seen.

The wire within the blind fonts a non-linear path between a pair of spaced contacts and preferably that path includes numerous changes of direction, so that it may traverse a significant area of the blind. Preferably at least two such paths are formed, by wires which are mutually independent, such that between them the wires traverse a major proportion of the area of the blind. The wire is preferably of a nonmagnetic material, for example aluminium, so that the presence or position of the wire in the blind cannot be detected magnetically.

The or each wire within the blind may extend continuously from a power-input contact to a further power-input contact or may follow a path between such a pair of power contacts which includes one or rrre pairs of intermediate contacts at the edges of the blind, by mEans of which the electric circuit may be interrupted by disconnecting from each other the intermediate contacts in a pair. In this way, movement of the blind away fram the adjacent frame may be detected at locations in addition to these at which power is supplied to the blind.

In one form of the security blind acoording to the present invention, the contacts upon the blind are in the form of plugs and the contacts for mounting upon the frame are sockets adapted to receive the plugs. Thus a socket may be one by means of which the power is fed to the circuits within the blind or may be a socket of which the function is to provide an electrical connection between an adjacent pair of intermedlate edge contacts on the blind. It is preferred that sockets and plugs of these two types resemble each other externally, even to the extent of providing false power leads to the second form of socket if desired, in order to confuse a potential intruder by disguising the nature of the plug or socket.

Where the function of a socket is to connect together adjacent inteddediate contacts as described, it is advantageous to make the electrical connection very sensitive, so that it is broken very easily. For example, the contact pins of a plug on the blind nay bye designed to be relatively short and therefore to extend for only a short distance into the socket. In addition, a spring means, for example a light helical canpression spring, may be provided to assist ejection of the plug from the associated socket.

When the security blind is in the form of a screen mounted upon hinges, or of a folding screen comprising two or more panels hinged together, the contacts by which power is supplied to the blind or transferred between adjacent panels may be incorporated in the hinges, such that a male contact on one hinge component engages a female contact on the other hinge occponent. In this way the power input point to the screen is disguised and in addition any attempt to lift a screen from its supporting hinges will interrupt the circuit and trigger an alarm or the like.

The electrical leads from the power supply to the contacts by means of which electrical power is fed to the circuits within the blind are preferably as inconspicuous as possible, since they are a potential source of vulnerability in any security system.

Thus in a preferred enbodmnent of the security blind according to the present invention, the power to those contacts is fed by means of a connecting strip which is punted upon the framework of the doorway or window aperture and which includes a wire or similar electrical conductor contained within it and running generally parallel to its length. The connecting strip, which is of an electrically insulating material, for example polyvinyl chloride or another plastics material, may be designed to engage a socket or hinge of one of the above-mentioned types at each of its ends, and/or to be interconnectable to a further length of strip.In this way, the connecting strip is adaptable to windows and doorways of different sizes and also the power input positions to a given blind may be changed.

In a particularly preferred form, connecting strips of the foregoing type may so engage a socket that the socket itself does not need to be punted on the adjacent frame but is retained there by the connecting strips. If, then, an intruder attempts to gain access by lifting the strip away fran the window or door frame, the socket may baoome disengaged and thus break the electrical circuit and activate an alarm. As a further feature, the socket may include a part which is autanatically ejected, for example by spring means, if the socket is lifted away from the frame.

The electrical circuit may be supplied with power from the mains supply via a suitable transformar, by means of which the voltage may be reduced to a safe working level and if desired rectified, or from a battery. Preferably the normal supply is from the mains and a battery is provided to power the circuit in the event of a mains failure.

If the circuit, or one of the circuits when two or rrore paths are provided over the area of the blind, is interrupted, a detector neans operates to produce an electrical signal, which may be used to operate an alarm or other warning. The alarm may be an audible one and/or a visible one, which latter may comprise a single warning light or may take the form of flashing room lights. Preferably any alarm, once activated, can only be switched off by neans of a switch operated by a secure key. Advantageously, sane form of waning is given if the power supply fran the mains fails.

The invention will now be further described with reference to the accompanying drawings, which illustrate, by way of exarrple only, two preferred embodiments of the security blind according to the present invention and Wherein:- Fig. 1 illustrates in elevation a first embodiment of the blind, for installation in a doorway; Fig. 2 illustrates the electrical circuit within the blind of Fig. 1; Fig. 3 illustrates, in vertical section, a plug incorporated in the blind of Fig. 1; Fig. 4 illustrates, in vertical section, a first form of socket to engage the plug of Fig. 3; Fig. 5 illustrates, in vertical section, a second form of socket to engage the plug of Fig. 3;; Fig. 6 illustrates a socket connecting strip in elevation from the front, partly in section; Fig. 7 is an end elevation of the connecting strip of Fig. 6; Fig. 8 is a perspective view of a second embodiment of the blind, in the form of a folding screen; and Fig. 9 is a vertical cross-sectional view of a hinge, suitable for use in the blind of Fig. 8.

The security blind 10 illustrated in Figs. 1 and 2 is in the foxm of an open mesh of opaque PVC, formed as a sandwich of two layers with several lengths of aluminium wire enclosed between the layers. As shewn in Fig. 2, which is a view corresponding to Fig. 1 but with the PVC mesh omitted, the wires form a number of circuitous paths 11 within the nesh, which run between points on the edge of the blind. At each of these edge points, two wires 11 terminate at contacts or terminal pins within a plug which is also sandwiched within the blind.Each plug is intended to engage a socket (described in nDre detail below) at a corresponding position on the adjacent frame of the dborway or window opening. Thus there is a socket to receive a plug at each of the points 12 to 17 (Fig. 2).

In this first e=bodiment, power is applied to the embedded wires at points 14 and 16; for example point 14 may be connected via the adjacent socket to a positive 12-volt DC source, point 16 being similarly connected to negative. At points 12, 13, 15 and 17, the sockets are such as to provide a direct link between the two pins of the plug. Thus the wires, plugs and sockets together form two non-linear paths of similar length extending between the points 14 and 16. These paths are so routed as to cover together a large part of the area of the blind 10.

Within reasonable limits, the points 12 to 17 are interchangeable in that any two of them may serve for power input and the others will simply interconnect adjacent wire ends.

Similarly, in forming the blind 10, the wires embeeded therein may be laid out along a wide variety of alternative paths.

The socket connector 18 illustrated in Figs. 6 and 7 is punted in lengths around a major part of the doorway or window frame, to which it is secured by screws. Aluminium wires 19 extending in a parallel pair down the length of each connector join sockets 20 in the ends of the connector. By means of corresponding pairs of pins projecting from the socket units 21, 22 (Figs. 4 and 5) and inserted into the sockets 20, these socket units 21 and 22 are held against the frame. Thus a large part of the perimeter of the frame is covered by connectors 18 alternating in sequence with socket units 21, 22.

The plug illustrated in Fig. 3 is one of six (in the illustrated embodiment) included in the structure of the blind 10 and located at the points 12-17 of Fig. 2. These plugs are indicated by the reference numeral 23 in Fig. 1. As shown in Fig. 3, the plug block 24, which supports the contact pins 25 to which the wires 11 are connected, is sandwiched between the two layers 26, 27 of the blind. Also sandwiched in the blind and spaced apart on each side of the plug block 24 are two presstuds 28.At each end of each socket oonnector 18 is a button or stud 29 to receive a press-stud 28. Thus, at each point around the frame of the doorway where a socket unit 21 or 22 is engaged on each side by a connector 18, a plug 23 is able to be inserted in the socket unit and held therein by one of the adjacent press-studs 28 clipped to a button 29.

As an alternative to press-studs 28 and buttons 29, the plugs 23 may be secured to the adjacent connectors by magnetic clasps 30 or by hook-and-loop fabric strips.

The socket unit 21 illustrated in Fig. 4 is a power-input unit having staggered sockets 31 to receive the pins 25 of a plug 23. The e sockets 31 are electrically connected to pins 32 at each end of the unit, by means of which electrical power fran an adjacent connector 18 is passed to the sockets and to the next connector in line.

The socket unit 22 is of the type for electrically connecting the two pins 25 of an associated plug. The pins 25 extend though sockets 37 and abut a copper plate 33, which is held in contact with the pins by a spring 34, the other end of which is located within a itrEber 35 disposed within the socket unit.

It will readily be understood that, when the various components are assembled around a doorway, for exampl the wires 11 are energised by electrical power from a remote source (not shown) via the connectors 18, sockets 21 and plugs 23, the circuits within the blind being ccatpleted via the plugs 22.

The plugs 22 are not a part of the external circuit, the pins 36 being dLitty pins serving to hold the plugs in place.

An attempt by an intending intruder to penetrate the blind wil1 break one of the electrical paths within the blind. Any attempt to lever a connector 18 fran the adjacent frame will either disconnect a socket unit fran the connector or allow the member 35 to be ejected from the relevant socket unit 22 and thus break the circuit at the pins 25. A break of electrical continuity of any sort will activate a relay (not shown) and thereby initiate an audible and/or a visual waring of the activities of the potential intruder.

The security blind illustrated in Fig. 8 is a folding screen consisting of four panels hinged together. Each panel comprises an openemesh SttUCtire formed from two superimposed layers 40 of PVC held within a frame 41. When the screen is extended as shown across a norway (exemplified in the drawing by French windows 42), it is retained in position by elongated retainers 43 at the top and bottan of the doorway.

Between the PVC layers 40 are sandwiched wires (not visible) in the manner of the wires 11 of the first emEcdinEnt. Power is fed to the wires via sockets 44, which are mounted upon the frame of the doorway by means of connectors 45 similar to the connectors 18. Plugs secured within the screen engage the sockets 44. Power is passed from the wires in each of the panels of the screen to the adjacent panel or panels via the hinges 46, one of which is shown in greater detail and to a larger scale in Fig. 9.

The hinge comprises two interlocking parts 47, 48 as shcwn, associated with respective adjacent screen panels 49, 50 and engaging each other via nylon lishes 51, 52. When a similar hinge is used to ncunt a screen upon a connector on a door or window frame, the part corresponding to hinge part 47 is preferably on the connector.

In a plastics socket 53, for example of nylon, in the hinge part 48, a carbon brush 54 is backed by a light spring 55. A short contact pin 58 projecting from the hinge part 47 enters the socket 53 and abuts the carbon brush 54 when the hinge is in its assembled condition. Wires 56 and 57 lead from within the screen panels 49, 50 to the pin 58 and carbon brush 54 reecti'rely.

The security blind of Fig. 8 functions in essentially the same nenner as that of Figs. 1 to 7. That is, the wires within the panels are a part of an electrical circuit which includes some at least of the hinges 46, sockets 44 and connectors 45.

Any interruption of that circuit produces an electrical signal to warn the householder that the blind has been in some way tampred with.

Claims (14)

1. A security blind comprising two superirrposed layers of synthetic polymeric material, at least one continuous electric wire sandwiched between said layers and forming a non-linear path between a pair of electric contacts spaced apart in the region of one or mDre edges of the blind, further electric contacts adapted for mounting on a dbor frame or window frame adjacent to the blind for disconnectable electrical connection to the contacts on the blind, a power supply to said framemounted contacts, and detector means for producing an electrical signal upon interruption of the electric circuit including said contacts and said wire.

2. A security blind as claimed in claim 1, in the form of a roller blind.

3. A security blind as claimed in claim 1, in the form of a folding screen or a screen mounted upon hinges.

4. A security blind as claimed in any of the preceding claims, wherein the superinposed layers are in the form of an open lattice.

5. A security blind as claimed in any of the preceding claims, wherein the wire forms at least two said non-linear paths.

6. A security blind as clairned in any of the preceding claims, wherein the wire is of a nonemagnetic material.

7. A security blind as clalined in any of the preceding claims, wherein the contacts upan the blind are in the form of plugs and the contacts for mounting upon the frame are sockets adapted to receive the plugs.

8. A security blind as claimed in any of the preceding claims, including one or more additional fra.=emDunted contacts adapted to interconnect electrically two mutually adjacent contacts on the blind.

9. A security blind as claimed in claim 8, wherein said additional frareemounted contacts are in the form of sockets having spring neans to assist ejection of blindemDunted contacts in the form of plugs.

10. A security blind as claimed in any of the preceding claims, wherein at least one frame-mounted contact and the contact on the blind to which it is connectable are together incorporated in a hinge.

11. A security blind as claimed in any of the preceding claims, wherein the power to the frameimounted contacts is supplied by a connecting strip which is mounted upan the frame and includes a linear electrical conductor.

12. A security blind as claimed in claim 12, including two or mDre said connecting strips, adapted together to suppOrt a said frame-mounted contact in the form of a socket.

13. A security blind substantially as hereinbefore described with reference to, and as illustrated in, Figs. 1 to 7 of the accompanying drawings.

14. A security blind substantially as hereinbefore described with reference to, and as illustrated in, Figs. 8 and 9 of the accompanying drawings.