| CLAIMS 1) A door and frame assembly or a window and window frame assembly fitted in at least one region between an edge of the door and a co-operating edge of the door frame or an edge of the window and a co-operating edge of its corresponding window frame with attempted intrusive device insertion warning means comprising a pressure sensitive component responsive to pressure applied thereto by insertion of an intrusive device by closing an electrical circuit which includes an alarm or other alert indicative of the intrusive device insertion event. 2) An assembly as claimed in claim 1 in which the pressure sensitive component comprises a strip of material comprising electrically conductive matter such as carbon particles sensitive to applied pressure and which renders the strip or at least part thereof conductive upon application of a localised pressure thereto. 3) A door and frame assembly or window and window frame assembly, wherein at least one edge of said door or frame or said window or frame is fitted with attempted intrusive device warning means comprising a pair of oppositely located and normally spaced apart elongate members, at least in part the opposing faces of said members being electrically conductive along their length, said opposing faces being capable of temporary mutual contact upon insertion of an intrusive device between said door and said door frame or window and window frame assembly in the region of said warning means, said temporary contact being sufficient to create electrical contact between said opposing faces that actuates an alarm or other alert indicative of an attempted intrusive device insertion. 4) An assembly as claimed in claim 1 or 3, in which the warning means comprises a pair of oppositely located elongate strips of material at least partly covered or coated with conductive material rendering them electrically conductive along at least part of their length. 5) An assembly as claimed in claim 4, wherein aluminium foil is wrapped around the strips or applied to part thereof as a film or coating. 6) An assembly as claimed in any one of claims 1 , 4 or 5 wherein the warning means comprises strips held apart in a rest condition absent an intrusive device bearing upon them. 7) An assembly as claimed in any preceding claim wherein the intrusive device is an attempted ligature such as a sheet. 8) An assembly as claimed in any preceding claim in which the warning device is fitted into a rebate in an uppermost edge of the door, or directly on top of the door and which optionally extends over most of the length of the door edge. 9) An assembly as claimed in any one of claims 1 to 7, wherein the warning device is inserted into and retained within the upper edge of the framework surrounding the door. 10) An assembly as claimed in any preceding claim, wherein the warning device is applied additionally to either or both side edges of the door or of the door frame surrounding the door or to both sides of the window or of the window frame. 11) An assembly as claimed in any preceding claim wherein the warning device extends in the uppermost edge of the door or window or door frame or window frame and continuously at least partly around a side edge or the side edges thereof. 12) An assembly as claimed in claim 11 in which the door or window is at least partly rebated along its uppermost edge and along one or both side edges thereof. 13) An assembly as claimed in claim 1 or any one of claims 4 to 13, wherein the warning device comprises strips incorporating a series of insulating protuberances and/or spacing means. 14) An assembly as claimed in any one of claims 1 or 4 to 13, wherein adjacent conductive strips are sealed at their remote ends from which conductive wires extend, useful in an electrical circuit including the alarm or alert. 15) A warning device as defined in any preceding claim useful in an assembly as claimed in any preceding claim. 16) An assembly as defined in any one of claims 1 to 14 or a warning device as claimed in claim 15 substantially as herein described. 17) An assembly as claimed in any one of claims 1 to 14 or a warning device as claimed in claim 15 substantially as herein exemplified in any embodiment. 18) An assembly as claimed in any one of claims 1 to 14 or a warning device as claimed in claim 15 substantially as herein illustrated in any figure of the accompanying drawings. |
This invention is concerned with improvements in door and window gap intrusion alert systems such as in anti-ligature devices and methods but more specifically with an alert means fitted to a door and/or door or a window frame to alert others when an intrusive device such as a sheet is inserted between the door and the door frame or between the window and its associated window frame and when pressure is applied.
For example the intrusive means such as a ligature could possibly be hung side on over the door whilst opened and when pressure is applied this would trigger an alarm or alert.
In certain places such as prison, mental hospitals or secure units it is desired to minimise the risk of an inmate or patient attempting to end their life by hanging. The risk of certain patients or inmates attempting to commit suicide by hanging is well known amongst the community charged with their care or supervision, i.e. prison warders and psychiatric hospital staff.
Indeed one may consider that those responsible for the welfare of such at risk patients or inmates have a duty to minimise as far as practicable, the opportunity for such patient or inmate to be able to cause harm or end life by whatever means, including by hanging from materials necessarily present such as bedding, sheets and the like.
It is already known to provide 'anti-ligature' door handles for example, wherein door handles are modified so as to reduce the risk of hanging therefrom by an at risk patient or inmate.
However, it remains a problem that other possible means of self harm or hanging can still be available, especially the continuing risk of an at risk patient or inmate attempting to hang themselves from the door or door frame of a cell or room in which they are located. Thus for example, it has been possible for an at risk patient or inmate to use a sheet wedged between the upper edge of a door and its associated frame with which to cause harm or death by hanging. For the sake of convenience we refer herein to a device by means of which a person may attempt to hang themselves as a 'ligature', and we refer to devices and means whereby the risk and/or opportunity of an at risk inmate or patient can be reduced as an anti-ligature device' or 'anti-ligature' means.
According to this invention there is provided in a first aspect a door and frame assembly or a window and window frame assembly fitted in at least one region between an edge of the door and a co-operating edge of the door frame or an edge of the window and a co-operating edge of its corresponding window frame with attempted intrusive device insertion warning means comprising a pressure sensitive component responsive to pressure applied thereto by insertion of an intrusive device by closing an electrical circuit which includes an alarm or other alert indicative of the intrusive device insertion event.
The pressure sensitive component may comprise a strip of material comprising electrically conductive matter such as carbon particles sensitive to applied pressure and which renders the strip or part thereof conductive upon application of a localised pressure thereto such as the insertion of an intrusive device between a door and door edge or between a window and window frame wherein such a strip is located. One such carbon containing material that may be commercially used for this purpose is known as Quantum tunnelling composite.
In a second aspect of the invention there is provided a provided a door and frame assembly or window and window frame assembly, wherein at least one edge of said door or frame or said window or frame is fitted with attempted intrusive device warning means comprising a pair of oppositely located and normally spaced apart elongate members, at least in part the opposing faces of said members being electrically conductive along their length, said opposing faces being capable of temporary mutual contact upon insertion of an intrusive device between said door and said door frame or window and window frame assembly in the region of said warning means, said temporary contact being sufficient to create electrical contact between said opposing faces that actuates an alarm or other alert indicative of an attempted intrusive device insertion. The warning means of embodiments according to the second aspect preferably, and optionally according to the first aspect, can conveniently comprise a pair of oppositely located elongate strips, e.g. of resiliently flexible plastic material but at least partly covered with or coated with conductive material such as aluminium foil to render them electrically conductive along at least part of their length. Aluminium foil may be wrapped around the strips or may be applied to only part thereof as a film or coating. The strips are conveniently held apart in a rest position, i.e. absent any attempted intrusive device such as a ligature device, in which condition the electrically conductive opposing faces of the strips are not in contact, anywhere along their conductive length. However, the strips are so arranged that they can be brought into temporary contact, and therefore close an electrical circuit, by the application of pressure thereto. In particular the alarm or other alert is so arranged to trigger by the level of pressure that would, e.g. be applied thereto by an at risk inmate or patient inserting a ligature device such as a sheet between a door and its door frame, in a region incorporating the present warning device.
Conveniently, the warning device can be fitted into a rebate in the uppermost edge of a door, or directly on top of the door by trimming the door and fixing or adhering to the top of the door, within a door and its corresponding frame assembly. Depending upon the length selected of the strips, such an arrangement can conveniently extend over most of the length of the said upper door edge. In alternative embodiments, such a two strip device could be inserted into and retained within the upper edge of the framework surrounding the door.
If required for even greater anti-ligature device warning effectiveness, the present warning means could be applied additionally to either or both side edges of the door or of the door frame surrounding the door. Whilst in practice it may be extremely difficult for an at risk patient to attempt to cause harm or hanging via a ligature device such as a sheet being wedged between a side of the door or door frame, it is nevertheless a risk that could be catered for.
In some embodiments of the present invention, the strips can be fashioned to not only extend in the uppermost edge of the door or door frame, but also to extend continuously at least partly around a side edge or side edges of the door frame, whilst preventing electrical contact between opposing faces of the device unless caused by an inserted intrusive device such as a ligature device pressing upon one of the strips. Such arrangements may benefit from the door being rebated not just along its uppermost edge but also partly along a side edge or the side edges thereof.
To separate the strips in the normal (at rest, uninserted) condition a series of insulating protuberances may be used width-wise such as small rubber strips. Alternatively, as subsequently illustrated a pair of such strips may be deployed lengthwise between the conductive elongate members. Additional spacing means may be deployed to help stabilise the uppermost of the strips, such as small rubber projections. The adjacent conductive strips can be sealed at their edges with bonding tape, and the remote ends of the strips can be affixed to lugs from which conductive wires extend. The said wires can be used in an electrical circuit including the alarm or alert.
In order that the invention may be illustrated, more easily appreciated and readily carried into effect, preferred embodiments of intrusive device insertion warning means within a door will now be described purely by way of non-limiting example only with reference to the accompany drawings, wherein:
Figure 1 is a view of an upper strip of a twin strip device;
Figure 2 is a view of the lower trip of the two strip device;
Figure 3 is a view of the assembled two strip device;
Figure 4 is a view of the device shown in Figure 3 protected by a sleeve;
Figure 5 is a view of the assembled, sleeve-protected device fitted into a rebate in the uppermost edge of a door and in contact with an attempted ligature device;
Figure 6 shows a modified intrusive ligature insertion warning device in exploded view fitted at the upper edge of a door;
Figure 7 illustrates an assembled warning device fitted within a soft rubber extrusion where a rebate is not needed for the door or door frame,
Figure 8 shows an underneath plan view, exploded view and cross-sectional detail of a completed ligature alert system housed within an extruded sheath and fitted to an upper door edge, Figure 9 is a partial sectional view of the upper corner of a door frame and door including the warning device and alarm sender unit,
Figure 10 is a side elevation of the door corner shown in Figure 9,
Figure 11 is a plan view along the notional section 11 - 11 identified in Figure 9, and
Figure 12 is a detailed part sectional view of an alarm sender antenna unit as fitted within the door of Figures 9 to 11.
Referring to the drawings and firstly to Figures 1 and 2 thereof, the anti-ligature warning means comprises a pair of plastics strips here shown in separation. The upper sheet 1 is an elongate plastics strip of rectangular shape with a contact face 3 having aluminium foil affixed thereto. One end of the sheet has provision to receive a metal lug 7 on the reverse side attached to conductive wire 7a which leads to an alarm or other electrical alert (not shown). In another non illustrated arrangement conductive glue can be bonded to the sheet without the intermediary of the lug. The lower strip 2 is similar to the upper strip also including an aluminium foil layer along its contact face 4. In order to keep apart the contact faces 3 and 4 in normal usage, i.e. before contact with and pressure from an attempted ligature, a series of insulating spacers 5 are used such as rubber frets, in spaced array along the length of lower strip contact face. In order to stabilise the upper contact face when the two strips are assembled together, a series of rubber points 6 can be deployed. The lower strip also has provision at one end on the reverse side to receive a metal contact lug 8 attached to a conductive wire 8a for electrical connection with the alarm or alert (not shown). Again as foreshadowed above, in another arrangement it is practical to dispense with such metal lug by using conductive glue bonded directly to the respective sheet.
The lugs 7 and 8 are to be in electrical contact with the aluminium foil on the contact faces of the strips.
Referring to Figure 3 the two strips 1 and 2 have been partly assembled by bonding together their side edges with insulated bonding tape. Referring to Figure 4 the bonded strips from Figure 3 have been placed into a protective insulating sleeve 9 that is also tamper resistant and may be made of strong cloth or rubber for example. The conductive wires 7a and 8a project out of one end of the sleeve 9 for connection to the alarm or alert (not shown).
Referring next to Figure 5, the assembled protected device 11a of Figure 4 is fitted into a channel rebate in a door along its uppermost edge 11 , or it could be placed directly on top of the door. It can be bonded into position with the two wires fitted into a channel 15 routered into the side edge of the door and affixed to a sender means 16 which connects wirelessly, or hard wired if preferred, to an alarm panel or a nurse panic alarm system (not shown). A timed delay can be built in of, e.g. 25 seconds or thereabouts.
The side edge 12 of door 10 is fitted into a door frame (not shown) via hinges 13.
An attempted ligature device in the form of a sheet 14 has been placed between the upper edge of the door fame (not shown) and the uppermost edge of the door, i.e. within the region of the door that includes the warning means. When the door is closed to securely mount the attempted ligature, pressure will be applied by the compressed upper part 14a of the interposed sheet to the strips 1 ,2 causing a temporary electrical contact between the conductive contact faces (until pressure release) and so activating the alarm or alert enabling swift attendance and release of the ligature.
Referring to Figure 6 the protected door 10 has side edge 12 and a wireless transmitter 16a inbuilt into that side edge connected to conductive wire 7a protruding through the upper edge 11 of the door 10. The intrusive device insertion warning system comprises a pair of conductive strips 3a, 4a rendered electrically conductive by the use of a metal- containing coating such as of copper and/or silver although other conductive materials may be used. In order to hold the conductive strips 3a, 4a in separation a pair of spacing elongate insulating strips 17 of neoprene foam are deployed between the opposing internal faces of those strips 3a, 4a.
The wires 7a (and 8a but not shown here) are bonded to the respective strip 3a (or 4a) by conductive glue to aluminium foil 19. The assembled strips 3a, 4a with interposed insulating strips are housed within an elongate rubber strip 18 of neoprene as illustrated in more detail hereafter.
Referring to Figure 7, the elongate strip 18 is shown as comprising a pair of wedge- shaped opposing edges between an internal channel section within which the pressure sensitive strip (3a) is located. There is a slit 20 along the length of the extrusion. Use of the extruded elongate strip 18 is advised where there is sufficient gap between the door edge and the corresponding door frame. Use of the wedge-like chamfered edges helps to minimise entrapment or catching of the warning device during normal opening and closing. Referring to Figure 8, different views of the warning device are illustrated using the same reference characters to identify the same components as previously described. In the underneath plan view, a hole 24 for one of the electrical cables (7a, 8a but not shown in this view) is apparent at one end 21 of the conductive strip adjacent the conductive aluminium tape 19 for terminating the cables in good electrical contact with the relevant strip.
At the other end of the strip an aperture 22 is provided for a pivotal hinge to project through, although such is not necessary in all embodiments. Additionally there are maintenance holes 23 to service the hinge.
As shown in Figure 9, the alarm antenna unit 16 is shown in more detail, being a generally rectangular unit fitted within a recess within the body of the door and covered by a removable wooden cover plate 22 flush with the outer door edge. The sender unit is surrounded by intumescent paper 21. Wires 7a,8a lead from the unit 16 to the warning device at the upper edge of the door, with its neoprene cover 18 outermost.
In Figure 10, the wooden cover plate is seen in more detail to blend in unobtrusively with the exposed door edge and to provide easy access for repair or replacement. Anti- ligature screws are used to secure this wooden cover in place.
Figure 11 is a corresponding plan view along the notional section 11 - 11 in Figure 9. One arrangement of a suitable warning device sender is shown in partial cut-away in Figure 12. A battery compartment houses a replaceable battery 25. The alarm sender is one of basically known type comprising a PCB designed to wirelessly transmit a warning signal to a remote alarm or alert means (not shown) upon closure of the electrical circuit caused by pressure applied to the warning means strips e.g. by an inserted ligature. The sender also includes a tamper switch 26, a terminal block 27, an LED indicator and the antenna 29.
Throughout this specification emphasis has been placed upon doors and door frames, but the invention may be deployed in windows and their corresponding window frames not necessarily to detect a ligature but to detect other intrusive insertion devices such as a jemmy, lever or other break-in tool. In such instance the corresponding alarm can be directed to the householders, burglar alarm company or to the police.