GB2102998A - Portable alarm - Google Patents

Abstract

A portable alarm comprises a casing 11, 12 containing a powered audible-signal-producing means 18 powered by a replaceable battery 17. The battery 17 is coupled to the signal-producing means 18 via an "on/off" switch 21 which is resiliently biased "on" and which can be held "off", against the biasing action, only as along as pressure is applied to and maintained on a trigger 25. If the pressure is released, a part 26 of the trigger 25 flies out of contact with a spring-loaded plunger of the switch 21 and leaves the switch permanently "on". The trigger 25 is prevented from parting company altogether with the casing 11, 12 by a tail 28 which fastens the trigger 25 to the casing. Other embodiments are described, e.g. where the casing is deformable for operating the switch, and where the trigger can part company altogether with the casing. <IMAGE>

Description

SPECIFICATION Portable alarm The invention relates to portable alarms.

One increasingly common and unpleasant feature of modern society is the number of attacks on individual people, especially elderly people or women, and especiaily when such people are walking home alone at night.

Conventional means of summoning help are of little use in such situations, because the victim is usually taken completely by surprise and is unlikely to have either the presence of mind or the change to operate a warning means.

The invention seeks to provide a simple alarm whichxkan easily be carried by people walking alone and which will automatically send out an audible alarm-signal, if the person is attacked, without the need to be positively operated.

According to the invention a portable alarm comprises a casing containing a powered audiblesignal-producing unit and also containing a source of power coupled to the unit via an "on/off" switch which is resiliently biased "on" and which can be held "off", against the biasing action, only as long as pressure is applied to and maintained on a switch-operating region of, or switch-operating part associated with, the casing.

The alarm therefore operates on the "deadmans handle" principle. If the user releases his or her grip on the switch-operating means, the resilient biasing means will automatically return the switch "on" and the alarm will sound until the switch-operating region of the casing, or the switch-operating part associated with the casing, is again gripped by the user.

The casing may be fitted with a trigger or a button which, when pressed, holds the switch "off" for as long as pressure is maintained.

Such a trigger or button could be initially inserted into the casing, pressed continuously to hold the switch 'off", and, if pressure is suddenly released, be designed deliberately to part company with the casing. If it then remains attached to the casing, for instance by a cord, the attacker then has to work out how to piece the trigger and casing back together to stop the alarm. If the trigger comes wholly away from the casing and is not retained, the attacker has to find both trigger and casing before he can begin to work out why the alarm cannot apparently be stopped. In either event, particularly if the trigger or button is made small and insignificantly coloured, he is much more likely to abandon the attack altogether and leave the alarm sounding.

The trigger or button could for instance be spring-loaded so as to positively fly out of the casing if pressure is suddenly released.

Alternatively a region of the casing itself may be resiliently deformable to hold the switch "off" without the need for a seprate trigger or button.

For example, if the casing incorporates a carrying handle, the under surface the handle may be designed to be squeezed resiliently to hold the switch "off', with the switch automatically coming back on again once pressure on the handle is released and the under surface returns automatically to its unsqueezed configuration.

Or, again, the whole casing may be small enough to fit comfortably within the users grasp, and squeezed to hold the switch "off", without the need for any positively-designated handle region.

Practical versions of the alarm will normally be fitted with some means to hold the switch "off" when the alarm is not being used. Preferabiy such means are wholly removeable from the alarm once the alarm is brought into use.

For example, a spring clip may fit resiliently onto the casing to hold a switch-operating trigger or button down, against the biasing action, when the alarm is not being used. To bring the alarm into use, the clip is removed and is stored elsewhere, and its holding pressure replaced by continuing manual pressure exterted by the user.

One portable alarm embodying the invention is shown in the accompanying drawing. It will now be described with reference to that drawing. It is only one example of forms which the invention might take.

The drawing is a single drawing showing the parts of the alarm in "exploded" perspective. The component of the alarm are housed within a casing which is moulded in shatterproof glass fibre-reinforced plastics (GRP) material. It is selfcoloured black during manufacture, so that it will be inconspicuous when carried at night. Its outer surfaces could be moulded with a "leather-look" finish, it could be shaped to look like a purse or a handbag, and it could conceivably even be built into the handle region of a purse or a handbag. As illustrated, it consists of a two-part plastics moulding, each part of which is a mirror image of the other part but for the provision of internallybored posts in one-half moulding and cooperating bosses formed in the other half-moulding.

Each half-moulding is referenced respectively 11, 12 in the drawing. The four posts in the halfmoulding 11 are referenced 13, and the four bosses in the other half-moulding 12 which cooperate with the posts 11 are referenced 14.

Self-tapping screws 1 5 pass through the bosses 14 and into bores formed in the posts 13 to secure the two half-moulding together.

Each half-moulding is lipped, as shown, to locate it positively against the other half-moulding before the screws 1 5 are driven home.

An internal rib 16 is moulded into the main body region of the half-moulding 11. It serves to strengthen the body, but its main purpose is to form effectively a compartment for a small 9-volt dry battery 1 7. The battery 1 7 constitutes the electrical power supply for an audible-signalproducing amplifier 18 to which it is coupled by wires 1 9 via a spring-loaded "on/off' switch 21.

The switch 21 is located in the handle region of the half-moulding 11. Another rib 22 is moulded internally into the handle region. One end face of the body of the switch 21 locates against one side of this rib 22. The other end face of the switch body locates against one of the posts 1 3. The spring-loaded plunger of the switch passes through a cut out 22A in the rib 22.

A terminal cap 23 connects the wires 1 9 electrically to the terminals of the battery 1 7 in releasable manner. When the battery 1 7 is spent, it can be replaced by simply unscrewing the screws 1 5 to give access to the batterycontaining compartment, unclipping the terminal clip 23, putting a new battery into the compartment, and replacing the clip 23 to complete the electrical circuit.

Alternatively the man skilled in this field could readily design a means of access to the battery 17 which did not involve separating the two halfmouldings 11, 12 of the casing.

The region of the half-moulding 12 which will accommodate the amplifier 18 is perforated, as shown, to allow the sound produced by the amplifier to issue from the casing. Additional posts 24 are moulded into the interior of the halfmoulding 11 to locate the amplifier 18 in place initially when the alarm is being assembled.

An elongate plastic switch bar 25 has two projections respectively 26, 27 moulded into it.

Both projections extend in the same general direction from the elongate axis of the bar 25.

The bar and its projections are so designed that the projections 26, 27 can be inserted into gaps formed in the under surface of the handle of the two half-mouldings, and the bar 25 can then be squeezed flat against the under surface of the handle.

In that position, the projection 26 pushes the spring-loaded plunger of the switch 21 down, against the biasing action of the spring, and holds the switch "off". A tail formed integrally with the bar 25, and projection 27, extends from one end of the bar. The tail is wrapped around the handle of the assembled casing 11, 12, its end portion is threaded through a hole in the projection 27, and it thus retains the bar 25 on the casing when manual pressure holding the bar against the under surface of the handle is released during use of the alarm.

The tail is referenced 28 in the drawing.

A resilient clip 29 is formed separately from the casing. In use, it fits over the handle of the casing and holds the bar 25 tight against the under surface of the handle. It thereby holds the switch 21 "off" when the alarm is not being used.

To bring the alarm into use, the clip 29 is removed from the handle of the casing 11, 12 and is stored elsewhere, for example in the pocket of a garment worn by the user. The holding pressure of the clip 29 is replaced by continuing manual pressure exterted by the user gripping the handle and the bar 25. As long as,the bar 25 is held flat against the under surface of the handle, the projection 26 holds the plunger of the switch 21 down, overcoming the biasing action of the spring loading means in the switch, and holds the switch "off".

If the users grip on the handle and the bar 25 is suddenly released, for example if the user is attacked and automatically releases his or her grip, the spring-biasing in the switch 21 pushes the projection 26 out of the way and the switch comes "on". The amplifier 18 sounds an audible signal and continues to sound as long as the battery 1 7 can supply electrical power to it. The bar 25 parts company with the handle of the casing, but does not positively fly out of the casing. It is retained by the tail 28. The attacker then has to work out how to stop the alarm from continuing to sound. He will most probably first jump on it to try to smash it. Because the casing is made of shatterproof GRP, he will find he cannot easily smash it. He then has to try to work out to piece together the bar 25 and the rest of the casing.If the bar is fitted wrong-way-round into underside of the handle of the casing, the projection 27 is not long enough to push the switch 21 "off". Rather than attempt any of this, if the attacker finds he cannot immediately destroy the alarm by jumping on it, he is more likely to abandon the attack altogether and leave the alarm sounding.

A tag 31 is moulded into the half-moulding 11 of casing. A hole is formed in the tag 31. The hole enables the alarm to be hung on a hook behind the door of a house or alternatively attached permanently to the door by a cord. .A householder who is reluctant to admit anyone, but who has to open the door before he or she can see who is there, can remove the clip 29, grip the handle of the alarm, and open the door. If the caller forces an entrance, the alarm will sound as soon as the householder releases his or her grip on the handle of the alarm casing.

The alarm illustrated, and described above, could be modified within the scope of the invention. For example the bar 25 could be done away with, and a projection corresponding to the projection 26 could be built into the inside of the handle of the casing. If the under surface of the handle were made resiliently deformable, the projection would push up against the springloaded plunger on the switch 21 when the user gripped and squeezed the under surface of the handle.

The clip 29 would then have to be a rigid Ushaped clip, fitting over the handle and compressing the handle so as to hold the switch "off" when the alarm was not being used.

Alternatively there may be no positivelydesignated handle region in the casing. Instead, the top and bottom surfaces of the casing could be made sufficiently resiliently deformable to be squeezed "off". Once again, a suitable rigid clip would have tobe provided, embracing the casing and compressing the deformable portions of the casing towards one another to hold the switch "off' when the alarm was not in use.

Other modifications will become apparent to those skilled in this field. For example, it is not essential for the bar 25 to part company altogether with the rest of the alarm. Even if the attacker manages to fit it back correctly into the handle region of the casing, he then has to hold the bar (and the rest of the alarm) permanently to prevent the alarm from sounding again in the absence of the clip 29. Again, the tag 31 can be used to padlock the alarm to a handbag: if the attacker snatches the bag, he invevitably carries off the alarm as well, and the alarm will continue to sound as long as the attacker is without the clip 29 or as long as he cannot work out how to stop the alarm.

Claims (10)

Claims

1. A portable alarm comprising a casing containing a powered audible-signal-producing unit and also containing a source of power coupled to the unit via an "on/off' switch which is resiliently biased "on" and which can be held "off", against the biasing action, only as long as pressure is applied to and maintained on a switch-operating region of, or switch-operating part associated with, the casing.

2. An alarm according to Claim 1 fitted with a trigger or a button which, when pressed, holds the switch "off" for as long as pressure is maintained.

3. An alarm according to Claim 1 or Claim 2 in which the trigger or button is initially inserted into the casing, pressed continuously to hold the switch "off", and is so designed that, if pressure is suddenly released, the trigger or button parts company with the casing.

4. An alarm according to Claim 3 in which the trigger or button is spring-loaded so as to positively fly out of the casing if pressure is suddenly released.

5. An alarm according to Claim 1 in which a region of the casing is resiliently deformable to hold the switch "off" without the need for a separate trigger or button.

6. An alarm according to Claim 5 in which the casing incorporates a carrying handle, the under surface of the handle being designed to be squeezed resiliently to hold the switch "off", and the switch automatically coming back on again once pressure on the handle is released and the under surface returns automatically to its unsqueezed configuration.

7. An alarm according to Claim 5 in which the casing is small enough to fit within the users grasp, and, when squeezed, holds the switch "off" without the need for the casing to incorporate a positively-designated handle region.

8. An alarm according to any of the preceding claims, in which the alarm is fitted with means to hold the switch "off" when the alarm is not being used, and such means are wholly removeable from the alarm once the alarm is brought into use.

9. An alarm according to Claim 8 in which a spring clip fits resiliently onto the casing to hold a switch-operating trigger or button down, against the biasing action, when the alarm is not being used.

10. A portable alarm substantially as described herein with reference to, and as illustrated in, the accompanying drawing.