GB2131213A - Alarm apparatus - Google Patents

Abstract

A self contained alarm apparatus for anti-theft or intruder alarm purposes consists of a housing (1) attachable or connectible to an article to be protected such as a video tape unit, the housing (1) containing an inertia sensor switch (2) responsive to movement and/or vibration associated with the article and in circuit with a high pitch sounder emitter or "siren" (3). A movement responsive device (20) responsive in particular to inclining movement of the article (8) and housing (1) is shown consisting of a ball (22) in a closed tube (21), rolling of the ball (22) causing activation of the inertia sensor (2). The housing (1) is attachable to the article (8) by double sided adhesive material or by Velcro fastening or by pull cord connection. The apparatus may also serve as an intruder alarm in which case it contains or carries a reed switch or more than one such switch in circuit with the sound emitter (3) and for co-operation with a magnet so that on their relative movement the sound emitter (3) is operated. <IMAGE>

Description

SPECIFICATION Alarm apparatus The object of this invention is to provide simple, compact and effective alarm apparatus especially but not exclusively for anti-theft use in relation to portable articles such as, for example, videotape units which at the present time are particularly liable to theft.

According to the invention alarm apparatus comprises a housing containing or carrying movement and/or vibration responsive switch means in circuit with a high pitch sound emitting device accommodated within the housing, which housing is adapted to be secured to a portable article to be protected or otherwise installed whereby when the apparatus is in the operative condition and on the switch means being activated e.g. by movement and/or vibration associated with an article in relation to which the housing is secured or positioned, substantially continuous sounding of the sound emitting device is effected.

Practical examples of the apparatus are shown in the accompanying diagrammatic drawings in which: Figure 1 is a plan view showing the components of the apparatus, Figure 2 is a similar side elevation, Figure 3 is an end view in the direction of the arrow Ill of Figure 1, Figure 4 is a circuit diagram and, Figure 5 shows an alternative mode of use of the apparatus.

Referring to Figures 1 to 3 the housing 1 which may be of strong and durable plastic material contains an inertia sensor switch 2 in circuit with a high pitch sound emitting device 3 and a battery or batteries 4 for self-contained supply of current to the circuit via a key operated on/off switch 5. A printed or other suitable circuit board 6 carrying an appropriate circuit is shown serving as a partition in the housing 1 and a typical circuit is shown in Figure 4. A battery condition indicator may be provided at 7, (Figures 1 and 2) and also a lamp such as a light emitting diode (LED) 50 to indicate that the apparatus is in the operative condition.

The inertia sensor 2 is preferably of the type in which a ball is finely located in a cup or similar support so that the moment the apparatus is subject to slight movement or even vibration the ball is dislodged to make or break a circuit as required, in this case to complete a circuit to the sound emitter 3.

Other suitable movement or vibration responsive switch means may be employed.

The sound emitter 3 is preferably that which is termed a "siren" and which emits a loud high pitch penetrating and continuous sound so that in addi tion to giving an audible warning over a consider able range the sound is such that it deafens the ears to other sound and is highly painful to the ears at close range.

Whereas the inertia sensor 2 is responsive to slight movement or vibration of the housing 1 or of an article such as a video tape unit 8 to which it is attached inclination of the housing 1 (i.e. with the article 8) may not be sufficient to activate the sensor 2 and to cover this possibility a sensing device 20 responsive to inclining movement is shown included and consisting of a member such as a ball 22 freely movable in a casing 21 shown of closed tubular form such that on the slightest inclination the ball 22 moves or rolls in the casing which movement itself is usually sufficient to activate the inertia sensor 2 and thus operate the sound emitter 3. Particularly, if the ball 22 rolls against one end of the tube 21 the impact ensures activation of the sensor 2 whilst it is found that even side movement of the ball 22 in the tube 21 is sufficient.The ball 22 may be located in a central rest position in the casing or tube 21 by a slight depression permitting movement of the ball in any direction on the slightest inclination of the housing 1.

However, a further sensing device 20 may be provided at right angles in plan view to the device shown or the normally horizontal device 20 may be inclined to the sides of the housing 1 so that the ball 22 is caused to roll whether the housing is inclined sideways or endwise.

Instead of the device 20 a mercury switch may be similarly arranged for causing the globule of mercuryto move in relation to suitable switch contacts which latter are connected in circuit with the sound emitter 3 for operating the latter e.g. through a delay device as referred to below. Here again the mercury globule may be located in the switch tube or casing by a slight depression or slight downward curvature of the tube.

The housing 1 is securely closed in a tamperproof manner and may be readily fitted in position on an article 8, e.g. unobtrusively at the back of the latter either by strong double sided adhesive tape which resists quick removal of the apparatus from the article 8, or as shown by detachable "Velcro" fastening 90, i.e. by means of co-operating pieces or strips of "Velcro" material adhesively affixed one to the housing 1 and the other to the article such as the casing of a video tape unit 8.

Instead of direct attachment the apparatus may be connected to the article e.g. by a pull cord 100 plugged into the housing 1 at 11 and which on movement away of the article causes activation of the sensor 2.

The apparatus may be otherwise secured or also secured to the article e.g. in a positive manner and in the case of a video tape unit 8 or other piece of mains operated equipment having flex to it the exterior of the housing 1 is provided with a clamp 10 or other suitable member through which the flex passes to the unit or article 8. In this way the apparatus is secured to the unit in such a manner that it cannot readily be removed. The clamp 10 may be such as to shield the flex against being cut between it and the unit 8.

The circuit of the apparatus includes provision for a delay (e.g. ten seconds) before the apparatus becomes operative after switching it on so that a person operating the switch 5 can move clear of the apparatus before it becomes responsive to vibration or movement. Similarly, there is provision for a delay (e.g. five seconds) before the sound emitter 3 operates after the apparatus has been subject to vibration or movement so that it can be switched off by an authorised person before sound emission takes place.

With the apparatus in position of use and switched on, and on any attempt by an intruder to remove the unit or article 8 the resulting movement and/or vibration immediately causes high pitch sound emission from the apparatus and whereas this is a deterrent in itself the fact that the apparatus cannot quickly be removed from the unit, makes any attempt to do so virtually impossible at close range to the sounding apparatus. Thus, the intruder is most unlikelytotakeawaythe unit with the sounding apparatus still attached to it.

In this regard the circuit is such that once it is activated by disturbance of the inertia sensor 2, the sound emitter 3 continues to sound and can only be stopped by switching off the apparatus and resetting the sensor. Any known or suitable circuit may be employed in the apparatus.

In addition to the above described practical applications of the apparatus it may be used for intruder alarm purposes in other ways such as a self contained door or window alarm. In such a case and as indicated in Figure 5 the housing 1 contains or carries a reed switch 24 which co-operates with a permanent magnet 25 mounted on the door or window fram. In the example shown additional or alternative positioning of the reed switch and magnet is indicated at 24', 25' i.e. according to installation requirements.

The or each reed switch 24 acts in place of the inertia sensor 2 and effects operation of the sound emitter 3 as soon as movement of the reed switch relative to the magnet 25 takes place on opening of the door or window. Alternatively, the housing 1 may be fixedly mounted on the door or window frame for co-operation of the or each reed switch 24 with a corresponding magnet or magnets 25 mounted on the door or window for movement therewith.

As well as effective operation in any of the above applications, the apparatus can be inexpensively produced and easily fitted in a matter of a few minutes.

Claims (12)

1. Alarm apparatus comprising a housing con taining or carrying movement and/or vibration re sponsive switch means in circuit with a high pitch sound emitting device accommodated within the housing, which housing is adapted to be secured to a portable article to be protected or otherwise installed whereby when the apparatus is in the operative condition and on the switch means being activated by movement and/or vibration associated with an article in relation to which the housing is secured or positioned, substantially continues sounding of the sound emitting device is effected.

2. Alarm apparatus according to Claim 1 wherein the movement and/or vibration responsive switch means consists of an inertia sensor switch.

3. Alarm apparatus according to Claim 2 wherein the housing contains movement sensing means responsive more particularly to inclining movement of the housing in order to cause activation of the inertia sensor switch or direct operation of the sound emitting device.

4. Alarm apparatus according to Claim 3 wherein the movement sensing means consists of at least one casing containing a member moveable therein.

5. Alarm apparatus according to Claim 4 wherein the movement sensing means consists of at least one tube containing a ball for rolling movement therein.

6. Alarm apparatus according to Claim 3 wherein the movement sensing means consists of a mercury switch in circuit with the sound emitting device.

7. Alarm apparatus according to any of the preceding claims wherein the housing is adhesively attachable to a said article, e.g. a video tape unit such as by double sided adhesive tape or like material.

8. Alarm apparatus according to any of Claim 1 to 6 wherein the housing is detachably attachable to a said article, e.g. a video tape unit such as by co-operating parts of "Velcro" fastening materials which are respectively affixed to the housing and article.

9. Alarm apparatus according to any of Claims 1 to 6 wherein the housing is attachable by pull cord connection to a said article.

10. Alarm apparatus according to any of the preceding claims wherein the housing is provided with an external clamp or the like for securely receiving an electric supply cable to a said article when the housing is attached or connected to the latter.

11. Alarm apparatus according to Claim 1 wherein the movement responsive switch means consists of at least one reed or like switch arranged to co-operate with a separately mountable magnet whereby on their relative movement the switch is conditioned to cause operation of the sound emitting device, e.g. for intruder alarm purposes.

12. Alarm apparatus substantially as herein described with reference to Figures 1 to 4 or Figure 5 of the accompanying drawings.