GB2348311A

GB2348311A - Door alarm system

Info

Publication number: GB2348311A
Application number: GB0006895A
Authority: GB
Inventors: John Edward Seymour
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-23
Filing date: 2000-03-23
Publication date: 2000-09-27
Also published as: GB9906602D0; GB0006895D0

Abstract

An alarm system for a premises including a door 6 having a locking mechanism comprises a first sensing member 10 to sense whether the door is moved from its closed to its open position, and a second sensor 28 operative to sense whether a bolt 24 of the locking mechanism is in its operative (locked) position, or its withdrawn (unlocked) position. The alarm system also comprises other sensing elements, in conventional manner. If the first sensor 10 is activated, e.g. by the door being moved from its closed to its open position, or one of the other sensing elements of the system whilst the locking mechanism for the door is withdrawn, as indicated by the second sensing member 28, the alarm is triggered in a first mode, which may give a supervisor time to disarm the alarm. Conversely if the first sensor member 10 detects opening of the door, or one of the other sensors is activated, whilst the bolt 24 is in its locked position, the alarm system is triggered immediately to an emergency mode.

Description

Title: Alarm Systems Description of Invention This invention is concerned with improvements relating to alarm systems, particularly such as are used to protect premises (such as homes, offices, shops and the like) against unlawful intrusion.

A conventional alarm system comprises one or more sensors located within and/or around the premises to be protected and which are connected to a control mechanism. On activation of the alarm system, the operator has a specific period of time to vacate the premises, and on entering the premises a specific period of time subsequent to entry to deactivate the alarm system, for example by a key or by the input of a PIN number, or both. In the event that the alarm system is not deactivated during this period of time, the alarm is triggered in response to a signal produced by one of the sensors and a trigger signal is generated which in addition to producing an alarm signal, may also initiate transmission of a signal to a central security office, such as a police station, so that the situation may be investigated.

Notwithstanding this, during a further specific period of time after the alarm is triggered the operator may telephone the security office and by quoting an identification code may cancel the call-out.

Unnecessary call-outs cause problems, in that they are chargeable and are a waste of time. In particular, an unnecessary call-out may delay response to a second incident which could have serious implications.

One of the major problems is that it is difficult to determine the difference between an inadvertent triggering of the alarm, as may occur when an operator returning to the premises protected by the alarm system fails to carry out a particular function, and a genuine triggering of the alarm, as occurs when the premises is being entered illegally.

It has been suggested in the specification of my European patent 0755550 that an audible and/or visual warning signal should be generated on the triggering of the alarm system by certain sensors at least, to alert the person entering the premises to the fact that the alarm has been triggered, and that it is necessary to take remedial action to prevent a call-out. Thus at the central security office, a period of time is allowed subsequent to an alarm system being indicated as being triggered, before a call-out occurs.

However on occasion, particularly where the premises being protected are shops, a burglar can enter the premises, and steal items of significant value, and leave prior to the alarm system being triggered, or before the security office commences investigating action.

It is one of the various objects of this invention to provide an alarm system which overcomes some at least of the problems currently encountered.

According to this invention there is provided a method of operating an alarm system of the kind utilised to protect a wing such as a door or window having a locking mechanism, wherein the alarm is activated into a first mode when the locking mechanism is in an unlocked condition, and is activated into a second mode when the locking mechanism is in a locked condition.

Thus, where the locking mechanism is a bolt, when the bolt is in a withdrawn (unlocked) position, the alarm be may activated into the first mode, corresponding to the normal mode in which triggering of the alarm in response to a signal produced by one of the sensors does not occur until the elapse of a predetermined time, allowing the operator to deactivate the alarm, and in the event that the alarm is not deactivated within this period of time, the alarm is then triggered. However, if the alarm is triggered without the bolt having been withdrawn (ie. as happens when the door has been forced) the alarm may be activated into the second, emergency mode which the alarm is immediately triggered in response to a signal produced by a sensor.

Thus in the case of a domestic premises, whilst in the normal manner the alarm system may in response to a signal generated by one of the sensors initially emit a series of warning bleeps during a period of time in which the alarm system may be deactivated, in the emergency mode the alarm system may be triggered fully immediately.

Similarly, in the case of larger premises, in the normal mode the conventional period of time, with optionally the conventional warning bleeps, may be utilised to allow the operator to deactivate the alarm in the conventional manner. Conversely, in the emergency mode additional to the alarm operating in full immediately, a call-out to the security station may be initiated immediately.

Where the alarm system is of the kind which under certain circumstances will issue a warning message advising that the alarm has been triggered, and allowing the operator, in the case of inadvertent triggering, to telephone the security station and, by giving a code word, to cancel the call-out, in the emergency mode no such opportunity need be given.

According to this invention there is also provided an alarm system of the kind comprising a plurality of sensors, and a control mechanism which may be set in an activated condition and a deactivated condition, the control mechanism when in its activated condition being responsive to a signal produced by one of the sensors to generate an alarm signal, characterised in that the control mechanism may be set in a first activated condition in which it so responds to such a signal after the elapse of a period of time during which the alarm may be deactivated, and a second activated condition in which it so responds to such a signal in a shorter period of time. Preferably, it may so respond substantially immediately.

The alarm system may comprise means, to which the control mechanism is responsive, to determine whether the control mechanism adopts its first activated condition or its second activated condition.

Thus said means may be afforded by an element of the alarm system such as a locking mechanism thereof.

Thus with the locking mechanism unlocked, the control mechanism may be set to its first activated condition, and with the locking mechanism locked, the control mechanism will adopt its second activated condition.

According to this invention there is also provided an alarm system for protecting a premises comprising a wing such as a door or window having a locking mechanism moveable from an operative condition to lock the wing and an inoperative condition in which the wing may be opened, the alarm system comprising : a) a first sensing means responsive to the position of the wing; b) a second sensing means responsive to the condition of the locking mechanism; and c) a control mechanism operative, with the alarm system activated in response to opening of the wing i) to generate an alarm signal of a first type where the first sensing means has sensed opening of the wing and the second sensing means senses that the locking mechanism is in its inoperative condition, and ii) to generate an alarm signal of a second type when the first sensing means senses opening of the wing and the second sensing means senses that the locking mechanism is in its operative condition.

Thus the alarm signal of the first type may be the conventional bleep, indicating for a short period of time that the alarm is activated, prior to the full alarm signal being produced at the end of said period of time by full triggering of the alarm, whilst the alarm signal of the second type may be the full alarm signal from the outset.

Preferably the first and second sensing means are provided by a sensing device comprising first and second sensing members associated with the wing and locking mechanism, respectively, and a control unit, conveniently a programmable microchip, to which signals from the sensing members are conducted, and from which a signal to the control mechanism of the alarm system is conducted.

Preferably the control mechanism comprises a parallel data-bar system across which sensing devices of the kind described above may be connected, other types of sensing device also being connectable across the data-bus system, such as conventional sensing devices or passive sensors.

There will now be given a detailed description, to be read with reference to the accompanying drawings, of an alarm system which is a preferred embodiment of this invention, having been selected for the purposes of illustrating the invention by way of example.

In the accompanying drawings: FIGURE 1 is a schematic sectional view showing a door having a locking mechanism, to which an alarm system in accordance with the invention has been connected; FIGURE 2 is a circuit diagram showing a busbar system connecting the system to a simple control mechanism.

In conventional manner the alarm system in accordance with the invention comprises a sensing mechanism comprising a first sensor unit 10, comprising a sensing member conveniently afforded by a reed switch mounted in a housing in the edge 5 of the door 6, and a passive transmitter 12, such as a small magnet, in a recess in the door jamb 4 which when the door is closed is adjacent to the reed switch. When the door is closed the transmitter holds the reed switch closed, and when the door is opened, the magnet moves away, and the reed switch opens.

Wires 15a, 15b extend from the reed switch to a control unit 18 of the sensing mechanism.

The locking mechanism of the door 6 similarly comprises, in conventional manner, a housing 20 mounted on the door 6, and a bolt 24 mounted in the housing for movement between a retracted position in which the door is unlocked (shown in full lines in Figure 1) and an advanced position in which the bolt extends into a keeper 26 in the door jamb, in which the door is locked (shown in dotted lines in Figure 1).

The sensing mechanism of this invention comprises a second sensor unit 28, comprising a sensing member afforded by a reed switch 28 mounted in the housing 20, and a passive transmitter such as a small magnet 30 in a recess in the bolt 24 which when the bolt is retracted is adjacent to the reed switch 28, and holds the reed switch closed. Two wires 32a, 32b extend from the reed switch 28 to the control unit 18.

The alarm system comprises a central control mechanism 40, from which a two wire data-bus 42a, 42b extends around the premises to be protected. A number of control units 18 of the kind described above may be connected to the data-bus by connecting wires 19a, 19b.

Other types of sensor unit, which may be passive infrared sensors, or sensing systems not in accordance with this invention, may similarly be connected to the data-bus.

In the use of the alarm system which is the preferred embodiment of this invention, when an operator (authorised user of the system) unlocks the lock correctly, the reed switch 28 is closed, and this is sensed by the control unit 18.

Thus when subsequently the door is opened, and the central control mechanism is triggered by opening of the reed switch 10, the alarm system is caused to operate in a first mode. This may involve emitting a bleeping noise to alert the operator to the fact that the alarm needs to be deactivated by entering the PIN number, and if this is not done within the time permitted, an alarm signal may be sounded, and the security station alerted.

Conversely with the reed switch 28 retained closed, as would be the case if the door were broken open without disengagement of the locking mechanism, opening of the reed switch 10 under these conditions causes the central control mechanism to generate an alarm signal of a second type, which can be considered to be an emergency mode. Under these circumstances, no period of time is allowed for entry of a PIN number, and if desired a signal is sent to a central control station requiring a high priority call-out to be executed.

It will of course be appreciated that, within the scope of this invention, a number of generally conventional changes may be made to the system. For example, the system may be operated with reed switches which are normally closed, or normally open.

For example, if the operator attempts to activate the alarm whilst the bolt is in its unlocked position, then the alarm system will not activate, and if desired a message may be given indicating the problem, and requiring the operator to take the appropriate action.

Whilst it is appreciated that the present invention does not resolve all problems of alarm systems, and (for example) would not recognise were the bolt to be withdrawn by the lock being picked, as distinct from the correct key being used, the invention enables the alarm system instantly to detect a condition where the door has been forced open without retraction of the locking bolt, the presumption being that under these circumstances there is a high degree of certainty that the intruder is unauthorised.

In the present specification"comprise"means"includes or consists of' and"comprising"means"including or consisting of'.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS 1. A method of operating an alarm system of the kind utilised to protect a wing such as a door or window having a locking mechanism, wherein the alarm is activated into a first mode when the locking mechanism is in an unlocked condition, and is activated into a second mode when the locking mechanism is in a locked position.
2. A method according to Claim 1 wherein the locking mechanism is a bolt, and when the bolt is in a withdrawn position, the alarm is activated into the first mode, and if the alarm is triggered without the bolt having been withdrawn, the alarm is activated into the second mode.
3. A method according to one of Claims 1 and 2 wherein the alarm system is of the kind which under certain circumstances will issue a warning message advising that the alarm has been triggered, and wherein in said second mode, no such warning message is issued.
4. An alarm system of the kind comprising a plurality of sensors, and a control mechanism which may be set to an activated condition and a deactivated condition, the control mechanism when in its activated condition being responsive to a signal produced by one of the sensors to generate an alarm signal, characterised in that the control mechanism may be sent to a first activated condition in which it so responds to such a signal after the elapse of a pre-determined period of time, and a second activated condition in which it so responds to such a signal in a shorter period of time.
5. An alarm system according to Claim 4 comprising means to determine whether the control mechanism adopts its first activated condition or said second activated condition.
6. An alarm system according to Claim 5 wherein said means is afforded by an element of the alarm system.
7. An alarm system according to Claim 6 wherein said element is constituted by locking mechanism of the system.
8. An alarm system according to Claim 7 wherein with the locking mechanism unlocked, the control mechanism is set to its first activated condition, and with the locking mechanism locked, the control mechanism is set to its second activated condition.
9. An alarm system for protecting a premises comprising a wing having a locking mechanism movable from an operative condition to lock the wing and an inoperative condition in which the wing may be opened, the alarm system comprising : a) a first sensing means responsive to the position of the wing; b) a second sensing means responsive to the condition of the locking mechanism; and c) a control mechanism operative, with the alarm system activated in response to opening the wing i) to generate an alarm signal of a first type when the first sensing means has sensed opening of the wing and the second sensing means senses the locking mechanism is in its inoperative condition, and ii) to generate an alarm signal of a second type when the first sensing means senses opening of the wing and the second sensing means senses that the locking mechanism is in its operative condition.
10. An alarm system according to Claim 9 wherein the alarm signal of the first type indicates a short period of time that the alarm is activated, prior to the full alarm signal produced at end of said period of time by full triggering of the alarm, whilst the alarm signal of the second type is the full alarm signal from the outset.
11. An alarm system according to Claim 10 wherein the first and second sensing means are provided by first and second sensing members associated with the wing and locking mechanism respectively, and a control unit to which signals from the sensing members are conducted, and from which a signal to the control mechanism of the alarm is conducted.
12. An alarm system according to any one of Claims 4 to 11 wherein the control mechanism comprises a parallel data-bar system across which sensing devices may be connected.
13. A method of operating an alarm system, when carried out substantially as hereinbefore described with reference to the accompanying drawings.
14. An alarm system constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.
15. Any novel feature or combination of features hereinbefore described and/or shown in the accompanying drawings.