GB2197516A - Security device - Google Patents

Abstract

The device is particularly applicable to protecting works of art, particularly pictures, and can be attached to the back of a picture frame (16, Fig. 4, not shown) and be held "off" when against a wall (50) but operates as soon as the picture frame is moved away from the wall giving an alarm, which can be audible and persist after release of a switch actuator 22, and may further be visible by releasing a tag 32. While the picture or other object holds the device against a wall or other surface, the switch actuator is depressed to hold a switch 20 open. Upon movement of the object, the actuator is released to close the switch and complete an alarm circuit, and the tag, which is held by string, is allowed to drop thereby providing an additional indication. Alternatively or additionally, similar operation to such switch response can result from cutting a picture underlayed by a strip having conductive properties changed by such cutting. <IMAGE>

Description

SPECIFICATION Security device This invention relates to security devices and systems and has application, inter alia, in the protection of pictures on exhibition or other display, particularly temporary and/or frequently changing exhibitions or displays which are open to reasonably ready access by viewers.

There is no difficulty in protecting rooms, galleries or other display spaces at times when they are closed, i.e. not affording access to viewers. Cost is virtually the only limit to the degree and sophistication of security systems at such times, and is not usually a problem in providing reasonable security at reasonable cost, as general intruder detection is not expensive. However, such systems are not suitable for use during opening times.

Security systems for operation during opening times and available at reasonable cost tend to rely upon integrity of an electric circuit linking several, often a large, number of protected items, which circuit has to be broken whenever a protected item is interfered with.

Examples of such systems range from using overhead track with suspensions down to pictures, which is suitable for a permanent or rarely changed exhibition gallery, to yet simpler wire loop circuits going through protected items and requiring local disconnection for their removal, which is used for displays of consumer electric goods in shops. However, the former is quite expensive and not very flexible for changing picture displays and the latter is not easy to implement for picture displays and is even more difficult to make sightly.

Sightliness is, in fact, often a significant matter in a display, as is the frequently related unacceptability of disturbing or risking damage to walls and/or wall coverings, for example in rooms whose decoration is special to a particular era and can be extremely costly. Such factors militate against embedding circuits or security devices in walls, or attaching parts of security devices to wall coverings especially on a temporary basis.

It is one object of this invention to make available a practical and advantageous alternative security provision.

In addressing the problems with that object in mind, it was perceived both that the primary objective of existing security systems was to detect intruders and/or to guard against actual theft, i.e. when the galleries etc were closed and possibly entirely unmanned or only lightly manned by watchmen, and that, when a gallery etc is open, i.e. normally manned, a satisfactory primary requirement is quickly to draw attention simply to the fact that a protected item has been or is being disturbed, but with ready identification of that item.

According to one aspect of this invention, a security device comprises a self-contained unit including self-powering means, alarm means activatable by the self-powering means, switch means controlling establishment of operative connection between the self-powering means and the alarm means, a switch actuator determining "on" and "off" states of the switch means by reason of proximity with a surface, and means for temporarily securing the unit physically in a relation with an item to be protected that assures activation of the alarm means when the item is moved. As applied to framed pictures conventionally hung on walls, units hereof will be attachable to lower rear parts of the framed pictures to bear against the wall, and can rely upon the mass of the framed pictures and gravity to hold the switch actuators to the "off" state of the switch means.Another aspect of this invention concerns such a method of protecting pictures etc.

preferred embodiments of this invention provide that the alarm means will be activated at least for a preset time, even if the switch actuator is immediately restored to determination of the "off" state of the switch means.

Alarm devices producing an audible noise are readily available and are a natural choice both for attracting immediate attention and for operation where the actual security unit hereof is not itself readily visible, say actually hidden from normal view by the protected item as is often preferred in application of systems hereof.

Alternative or additional indication of disturbance is, of course, possible, whether visual or otherwise and whether or not linked with some remote identification equipment, say as a receiver for coded sound etc. and serving to tell staff at that equipment which protected item is concerned.

In fact, for some simple embodiments of this invention, a mechanical visual indicator or flag is provided by way of a tag that is released from the unit behind a picture when the latter is moved and drops down below the frame of that picture. Such a tag may fit between the switch actuator and the wall, say held on a flexible cord, chain or the like, and say required to be in position to hold the switch actuator in the position corresponding to "off". i.e. there is a switch actuating clearance when the tag is not in place.

At least as alternative units, such proposals constitute other aspects of this invention.

Other applications for units of this invention including their temporary affixing proximate to the protected article and held "off" by that article, say affixed to a display tabie or shelf next to, perhaps behind, the article concerned.

Then, the unit will go "on" if the article is moved relative to the unit.

Further, in relation to framed pictures, such as valuable paintings, same are vulnerable to being cut from their frames, at least unless covered with glass or other protective transparent sheet, which normally requires that framing includes a fillet or the like to space the glass or other protective sheet from the painted surface and is generally disadvantageous in terms of best display and appreciation.

It is another object of this invention to afford protection, actually detect cutting of a picture or the like.

According to another aspect of this invention, there is provided associated with or for association with a picture or the like security means including a strip emplaced or emplaceable between sheet material of the picture or the like and support means therefor, the strip affording electrical conduction properties between connections thereto which properties change when the strip is cut by a blade or the like penetrating thereto through said sheet material.

Some embodiments of this invention use a conducting path of the strip which is broken by said blade, i.e. are of a connection-breaking type. Other embodiments use conducting paths that are normally mutually disconnected and become electrically connected by said blade, i.e. are of a connection making type.

For a conventional oil painting on canvas over a stretcher frame, the security strip hereof is conveniently emplaced by sandwiching between the canvas and side members of the stretcher frame.

A particularly advantageous security strip hereof has an electrical conductor or conductors in or on a thin flat insulating carrier, which can be sheet material, usually though not necessarily flexible, say a plastics film.

A suitable insulating carrier for connection making embodiments may hold conductors so that they can never directly contact each other in which case the security means relies upon conductivity of a cutting blade to afford electrical connection between the conductors.

That may be achieved, as will be specifically described, where the conductors are on opposite sides of the carrier, at least where such carrier is at least as readily, preferably more readily cut, than the sheet material of the picture. The conductors can be of narrow strip form or broader, and if of strip form, it can be advantageous for one to be broader than the other in a manner consistent with possible inclination of a cutting edge in use. However, the conductors could be on one side only of the carrier, then sufficiently closely spaced to be interconnected by any expected cutting blade.

Alternatively, the carrier could permit conductor diplacement into mutual electrical contact, say by being of mesh or other expanded partially open type, though it may then be necessary or advisable or preferred to dispose at least one conductor specifically to be capable of being displaced,say by virtue of free or excess length across a carrier aperture and of inherently less resistance to bending than to being severed by any expected cutting blade.

In practice, it has been found to be satisfactory to use conductive layers on each side of a plastics film, actually to do so using metal foil and double-sided adhesive tape. Such security means is satisfactorily flat and thin, and can be readily emplaced between sheet material of a picture or the like and a backing surface therefor, specifically of an oil painting on canvas between the back of the canvas and a stretcher side by adhering to either, say using further adhesive tape such as masking tape.

Strictly, such security cutting means is required only as one local device on one side of a picture, and it is expected that such will be preferred, though more extensive application could be made via several such devices or one or more devices covering more of this picture backing.

Wires to and from the conductors are readily taken away, say through or past a stretcher side or sides to a connection-detect device or system, which, as a device, can be local to the picture or the like concerned, say attached to the rear of the picture or its frame and of a type including a latching relay or equivalent at least where of self-powered, say battery-operated type.

A suitable insulating carrier for connectionbreaking embodiments of this invention need only assure that a blade will break a single conductor associated therewith. Current drawn by such a conductor should be iow, at least where the security means is locally powered by a battery, then perhaps preferably of a rechargable type.

Preferably, embodiments of this invention are implemented using a connection to a security device of the first-mentioned aspect of this invention, which could then perform a dual role.

Practical implementation of this invention will now be specifically indicated, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of one unit hereof partly broken away; Figure 2 is a plan view of the same unit; Figure 3 is an electric circuit diagram; Figure 4 shows use in connection with a painting or the like; Figure 5 shows an alternative electric circuit diagram; Figure 6 shows in plan arrangement of components on a circuit board; Figure 7 is a section through a complete device using line X-X of Figure 6; Figure 8 is a plan view of a complete device also showing further the section line )(-X; Figure 9 is a section through a cutting sensor for connection making embodiments;; Figures 1 0A and 10B show alternative cutting sensors for connection-making embodiments; Figure 11 is a fragmentary plan view partly broken away of a picture equipped with a cutting sensor hereof; Figure 12 shows an outline electrical circuit; Figure 13 is a section through a cutting sensor for connection-breaking embodiments; and Figure 14 shows an outline electrical circuit.

In Figures 1 and 2, a security unit 10 has a generally cuboid case 12, though the shape of the case is not important hereto. One major surface 10A carries attachment means in the form of double-sided adhesive tape 14 by which it is further shown in Figure 4 attached to the lower back part of a framed picture 16, hung on a wall 50, though other securement means can be used if desired or preferred.

Figure 4 also shows, dashed, optional combination with the picture cutting alarm to be described relative to Figures 9 to 14. The other major face 10B is shown apertured at 18 for protrusion therethrough of an actuator 20 of a microswitch 22, actually for movement against spring bias (see 24 in Figure 3) by a blade member 26 hinged into the case 12 at 28, though any other convenient manner of operation can be used (including having the actuator 20 directly engaging the wall 50).

The position of the switch-operating parts 20, 26 is shown to be within a stepped recess 30 that accommodates a tag 32 whose thickness is such that, with the tag 32 in the position shown and the switch operating parts 20, 26 fully depressed, the back surface 32B of the tag will be slightly proud of said other main surface 10B of the unit 10. Removal of the tag 32 from the recess 30 will release the switch-operating parts 20, 26 and the switch 22 will change its state from "off" to "on".

The tag 32 is shown attached to the case 12 by a cord 34 extending between a tag anchorage 36 and a case anchorage 38, the latter being shown in a recess 40 conveniently of less depth than the recess 30, see Figure 2 and dashed in Figure 1.

When installed on the back of a hung picture 16 or the like (as indicated in Figure 4) the tag 32 will be held in position by the effect of gravity on the mass of the picture 16 where the latter is hung in conventional manner relative to a wall surface 50 using a hook or hooks 42 and cord 44 extending between eyelets 46 at each side of the picture frame. If the picture 16 or the like is disturbed, specifically its bottom moved away from the wall surface 50, the tag will fall out and be visible below the picture frame, see right hand diagram of Figure 4. That, of course, gives a visual indication of disturbance of the picture 16 or the like. Moreover, recessing of the tag position will assure a clearance for micro-switch actuation until the tag is replaced.Felt 48 may be fixed on the surface 10B and/or back of the tag 32 further to protect special wall-coverings.

Additionally, however, the case 12 is indicated as containing an alarm device 52, usually of audible sound type, see speaker indication in Figure 3; also a battery 54 for electrical self-powered operation of the unit 10 on a self-contained basis. Control of operation is basically by way of the microswitch 22 so that the alarm device 52 is energised whenever the microswitch 22 goes to the "on" state, i.e. when the tag 32 falls out or the switch operating parts 20, 26 are otherwise not held in their "off" demand position.

Such direct and immediate operation of the unit 10 is indicated in Figure 3 via circuit paths 56A, B, C and D. If desired, a delay device could be included to give an interval between disturbance and operation of the alarm device 52, perhaps to allow inadvertent movement of the picture 16 to be corrected without alarm operation.

However, another provision is shown to guard against a disturber quickly pushing the switch operating parts 20, 26 back to the "off" demand state. That is by way of a timer device 58 having a trigger connection 58A from the circuit path 56B and then serving to hold another switch 60 closed for a preset time interval. The switch 60 controls another energising path for the alarm device 52 via branch circuit paths 62A, 62B from path 56A to path 56C. Conditioning branch circuit paths 64A, 64B from path 56A to path 56D are also shown for assuring that the timer 58 is ready for triggering.

In an alternative embodiment, see Figure 5, a device enabling and disabling switch 80 is shown for operation to the "on" state at installation. Also, specific timer circuitry is indicated relative to an audible alarm 82 of a type receiving supply current when the switch 80 is "on" but further requiring a control signal at 84 in order to be activated. Such control signal is shown as available from the collector-emitter path of transistor 86 when it is switched on by operation of the normally "off" microswitch push button 88. When that happens, a capacitor 90 is also charged and thus assures persistence of conduction of the transistor 86 and thus presence of the control signal on line 84 for a preset time even if the microswitch push button 88 is immediately restored to its off state.

Specific organisation of components of such an embodiment, including battery 92, is indicated in Figure 6 on circuit board 94 having a slot 96 for access by a tool to operating slider 808 for the switch 80. The board is also shown with screw holes 98 for its securement to a picture frame, and with dashed lines at positions corresponding to placement and securement thereto of a cover 75 with an aperture 76 for the microswitch push button 88, see Figures 7 and 8. Also shown in Figures 7 and 8 is a shield sheet 77 itself apertured at 78 for the micro-switch button 88.

Moreover, Figure 7 shows a preferred holdoff member 79 for the micro-switch push button 88 in the form of a circular tag with an edge chamfer 79C from a diameter greater than that of the cover aperture 76 to a diameter less than that of the cover aperture 76 so as to be readily centred thereat.

It should be evident that the described alarm units are capable of giving two different indications of disturbance of an associated picture 16 or the like, one via its audible alarm device and the other via its tag. That is on a basis wholly local and individual to that picture 16 or the like.

It should further be appreciated that units hereof can readily be incorporated into a larger system, for example where the alarm devices produce different signals detectable by or for a central unit, say as different pitch audible signals and suitable detection means, or as other unit-coded signals. One possible and simple communication system could use mains wiring with a sound pick up device in the display area and a sounding device in another place.

Moreover, units hereof are readily used, or adapted or modified to be used, in relation to protecting items other than pictures or the like. Thus, a unit as described might be sandwiched between a surface and a protected item bearing on its tag, or be attached to the same surface as supports the protected item, say by adhesive tape at its end surface 30 or either of its side surfaces 72, 74 for Figures 1 and 2. However, it may be preferred to use a different housing from Figures 6 to 8, and/or to omit the tag and have the case or cover without any recessing, so that the microswitch push button bears directly on the protected item, for example a valuable piece of pottery, scuipture or whatever.

Figure 9 shows electrically insulating tape 100, such as double-sided adhesive plastics tape, with conductors 102 and 104 on opposite sides, say of metal foil adhered to the tape. The conductors 102, 104 may each be continuous sheet, or of strip form, then preferably with one strip wider than the other. A conducting knife blade can thus cause electrical connection between the conductors 102 and 104 as it cuts the tape 100.

The overall strip device 110 of Figure 9 will be thin and readily emplaced between sheet material of a picture or the like and a support therefor, see canvas 120, stretcher side 122 and frame 124 in the fragmentary brokenaway view of Figure 11. If not done directly using adhesive on one side of the strip 110, that is readily achieved using broader masking tape thereover, see dashed at 106 in Figure 9, which also shows further narrower masking tape 108 at the other side of the strip if it is desired or necessary for the conductor 102 not to contact the sheet material of the picture or the like. Electrical connections are shown at 112, 114 to the conductors 102, 104.

Figure 10A shows a variant in which conductors 102A and 104A are on the same side of tape 100A, but close enough to be bridged by a cutting blade.

Figure 10B is fragmentary and shows a variant in which tape is replaced by open-structured carrier material 100B, shown with staggered apertures, and conductor first-encountered (104B) by a cutting blade is shown looped at each aperture so as to go onto contact with the other conductor (102B). The former conductor (104B) is shown as two conductors both connected to electrical connection 1 14B, and the latter conductor (102B) as broader to be contacted by either of the conductors 104B.

Figure 12 shows one electric circuit suitable for association with the strips of Figures 9 and 10, basically comprising an audible alarm device 152 and a battery 154 in a circuit 156A, B, C and D including connections 142 and 144 for lines 112 and 114 from the device 110 (or 110A, 110B). A relay 158 is also shown with a trigger line 158A from the circuit part 1 56B after the connections 142, 144 and controls normally-open contacts 160 in a circuit path 156B after the connections 142, 144 and activating the alarm 152 when the contacts 160 close. The relay 156 is of a latching type so as to respond to momentary energisation of its trigger line, 1 56A thereafter to hold the contacts 160 closed until resetting. A latch/hold connection 164A, 164B is shown.It will be appreciated that the relay 160 may be of wholly electronic type, and alarms etc. other than audible could be used.

Figure 13 shows a strip suited to connectionbreaking for sensing attempted cutting out of a picture. A tape 100C carries a conductor 102C on one surface, and is shown doubled over for convenience of making connections 112C, 1 14C at one end only.

An electronic circuit for connector-breaking embodiment is shown in Figure 14 again relative to an audible claim 112 and to a battery 154 in a circuit 156A, B, D. This time, the circuit 1 56 is shown interrupted by contacts 170 controlled by a relay 1 72 shown with an energisation circuit path 174A, 1 74B across the contacts 1 70 and including connections 142C, 144C to the strip 110C. The contacts 1 70 are of normally-closed type held open only by energisation of the relay 1 72. Thus, once the conductor 102C of the strip 1 10C is broken, the relay 172 will cease to be energised and the alarm 152 will sound until the relay is reset.

Testing of the Figure 14 circuit could simply be by disconnecting one of the connectors 142C, 144C. The relay hold circuit 171C should, of course, be of very low current drain.

The circuitry of Figure 12 or Figure 14 can readily be in a small housing attaching to the back of a picture, and could be as in the embodiments of Figures 3 or 5, see dashed connections bridging the micro-switch push buttons thereof, and the dashed provisions of Figure 4.

Claims (14)

1. A security device comprising a self-contained unit comprising self-powering means, alarm means activatable by the self-powering means, switch means controlling operative connection between the self-powering means and the alarm means, and a switch actuator determining "on" and "off" states of the switch means relative to enabling said operative connection, said switch operator so determining by reason of proximity with a surface, and means for securing the unit physically relative to an item to be protected so that activation of the alarm means occurs when said item is moved.

2. A security device according to claim 1 for protection of a framed picture and like item, wherein the device is placed between said item and a wall on which the picture is bung.

3. A security device according to claim 1 or claim 2, wherein said unit is secured to the back of a framed picture or like article where it will bear against a wall on which the picture is hung and affording said surface.

4. A security device according to any preceding claim, wherein said switch actuator comprises or further comprises a member loosely sandwiched between said surface and said unit until said item is moved.

5. A security device according to claim 4 with claim 3, wherein said member comprises a tag or flag falling to give visual indication that said item has been moved.

6. A security device according to claim 5, wherein the tag or flag is secured to the unit by a flexible cord, chain or like means.

7. A security device according to any preceding claim, wherein the alarm means is operative for at least a preset time even if the switch actuator is immediately restored to its "off" state.

8. A security device according to any preceding claim, wherein, at least until said item is moved the device is hidden by said item as normally viewed.

9. A security device for preventing cutting a picture out of its frame, comprising a strip emplaceable between sheet material of the picture'and support means therefor, the stripaffording electrical conduction properties between connections thereto which properties change when the strip is cut by a blade or the like penetrating through said sheet material.

10. A security device according to claim 9, wherein the strip has a conducting path that is broken by said blade or the like.

11. A security device according to claim 9, wherein the strip has conducting paths that are normally mutually disconnected but become electrically connected by said blade.

12. A security device according to claim 9, 10 or 11, wherein detection circuitry is of a similar type to that employed in a device according to claim 1 or claim 7.

13. A security device according to claim 12, wherein the strip connections are alternative to the switch means of any one of claims 1 to 8.

14. A security device arranged and adapted to operate substantially as herein described with reference to and as shown in Figures 1 and 2 or Figure 3 or Figure 4 or Figure 5 or Figures 6 to 8 or any one of Figures 9 to 14.