EP2439710B1

EP2439710B1 - Alarm apparatus

Info

Publication number: EP2439710B1
Application number: EP11183945.2A
Authority: EP
Inventors: Matthew Phelps
Original assignee: Cooper Security Ltd
Current assignee: Cooper Security Ltd
Priority date: 2010-10-11
Filing date: 2011-10-05
Publication date: 2020-02-12
Anticipated expiration: 2031-10-05
Also published as: GB2484555B; GB201017892D0; EP2439710A3; GB2484555A; EP2439710A2; GB201017104D0

Description

The present invention relates to alarm systems, particularly to intruder alarm systems, where the components of the alarm system are provided with anti-tamper means. The components of the alarm system are said to form alarm apparatus. Alarm systems generally contain a control unit that is connected to one or more sensors and one or more alarm indicators (sounders, etc). Upon activation of the alarm, a trigger signal from each activated sensor is transmitted, either through wires or wireless means, to the control unit and alarm sounders.
Such alarm systems can also incorporate expander units. These expander units provide more capacity so that more sensors, sounders, etc can be incorporated into the alarm system. Upon activation of the alarm, a trigger signal from each activated sensor that is connected to the expander unit is transmitted, through wires or wireless means, to the expander unit, and the expander unit then transmits the trigger signal, through wires or wireless means, to the control unit. Such alarm apparatus are often fitted to walls of buildings in exposed, accessible locations and so are usually fitted with anti-tamper means. An example of a prior art alarm apparatus provided with anti-tamper means is given in US2005/219046A1 . These anti-tamper means generally comprise a spring connected to a microswitch, and the spring extends between the alarm apparatus and the wall to which the alarm apparatus is mounted. The spring is usually positioned against the wall in at least a partially compressed configuration.
If an attempt is made to remove the alarm apparatus from the wall, the compressed spring is allowed to relax, triggering the microswitch, and generating a 'tamper' condition at the alarm apparatus. This causes a signal to be transmitted to the control unit and this may set off an alarm.
However, it is possible to interfere with the spring of such anti-tamper means.
In addition, such anti-tamper means are designed to be used with an alarm apparatus fitted to a flat surface. These anti-tamper means do not work so well for uneven surfaces.
The present application arose in an attempt to provide an improved alarm apparatus for alarm systems.
According to a first aspect of the present invention there is provided an alarm apparatus for an alarm system as recited by Claim 1.
The dependent claims specify preferred but optional features.
The alarm apparatus can be a control unit, a sensor, an alarm indicator, an expander unit, or any other components of the alarm system that can be mounted to an external surface. Anti-tamper means are usually provided on expander units, so preferably, the alarm apparatus is an expander unit.
The alarm apparatus may comprise a housing, such as a box, which houses one or more alarm components, eg a housing for one or more sounders, sensors, control devices, power supplies, expanders or otherwise.
The protective means is arranged to be held captive by the housing yet able to float axially therewith. This allows the amount by which the protective means extend outwardly from a part of the housing to vary, and enables the protective means to extend across a range of different sized gaps formed between the housing and a surface to which the alarm apparatus is mounted. The protective means may fully extend across the gap, or partly across the gap.
The shroud preferably fits at least partially around the anti-tamper means and has at least one hollow end. The shroud can have many different shapes, for example, the shroud can be in the form of a tube, or a cap, or a plate, or a pair of parallel or non-parallel plates.
The shroud may have one hollow and one closed end. The closed end can project outside the housing of the alarm apparatus, and the hollow end can be retained inside the housing. It is also possible to have the cap in an inverted configuration, with the closed end retained inside the housing, and the hollow end projecting outside the housing.
The shoulder may limit the size of the gap across which the protective means may fully extend. The maximum size of the gap would be the amount by which the shroud extends outwardly from the housing when the shoulder is in contact with the housing.
The shoulder may be separable from the shroud. In some embodiments, the shoulder is attached by a weakened portion to the body of a shroud, for example, so that the shoulder may be frangibly separable from the shroud. However, other means could be used to separate the shoulder from the shroud. It may also be possible to repeatedly separate and reconnect the shoulder and the shroud, for example, using a clip or a screw mechanism. The separability allows the same shroud to be used with or without the shoulder depending on the circumstances.
The anti-tamper means may comprise a compressible component and a switch. The compressible component may be a spring, and the switch may be a micro switch.
If the shroud is in the form of a cap having one open end and one closed end, the compressible component is preferably compressed against the closed end of the shroud, and the closed end of the shroud is preferably in contact with the external surface.
There may also be a means for fixing the protective means to the surface on which the unit is mounted. Preferably, the shroud is screwed to the external surface. However, the shroud could also be glued, nailed or otherwise attached to the surface. The shroud can be provided with projections through which screws, nails or other fixing means can be fitted, or the fixing means can be fitted through a closed end of the shroud, or through the shoulder.
Fixing the shroud to the external surface enables the protective means to be used with uneven external surfaces. If the external surface is uneven and no fixing means are provided, it is difficult to arrange the alarm apparatus so that the protective means are reliably fixed against the external surface, resulting in the protective means often functioning less effectively. Providing fixing means with the protective means overcomes this problem.
At least part of the housing of the alarm apparatus is preferably formed with a pre-formed shroud. The shroud is preferably separable from the housing, preferably by means of a weakened portion, for example a frangible portion. The shroud can be separated from the housing before or after the housing of the alarm apparatus has been fully assembled.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which;

Figure 1: is a side view of an expander unit in situ.
Figure 2: is a cross-sectional side view of an expander unit in situ.
Figure 3: is a cross-sectional side view of a further arrangement, and
Figure 4: is a panel for forming part of the housing of an expander.

In these embodiments, the invention comprises an expander unit. However, it will be appreciated by a person of skill in the art that the alarm apparatus can also comprise a control unit, a sensor, an alarm indicator, or any other components of the alarm system that can be mounted to an external surface.
Figure 1 illustrates an expander mounted to a surface such as a wall. The expander unit 1 generally comprises housing 2, anti-tamper means 3, and protective means 4. The expander unit is mounted to an external surface 5 (the means for mounting the expander unit to the external surface are not illustrated in the figures). The protective means 4 is in the form of two parallel plates 6a, 6b which protect the anti-tamper means 3 by restricting user access to the anti-tamper means. In other embodiments only one plate need be provided, or more than two plates can be provided, and the plates may be planar or arcuate, and the more than two plates need not be parallel.
Referring to figure 2, in an arrangement in accordance with the invention, the anti-tamper means 3 comprise a switch 8 and a spring 9, and the protective means 4 comprise a shroud 9, in the form of a cap, with shoulders 11. The shroud 10 fits through an opening 13 in the expander unit. The bottom surface 12 of the shroud 10 protects outside the expander unit 2, and the shoulders 11 are retained within the expander unit 2. The shoulders 11 have an outer diameter that is larger than the diameter of the opening 13 and so the shoulders prevent the shroud 10 from being fully removed from the expander unit 2 through the opening 13.
The shroud 10 is held captive within the housing 2, yet able to float axially (direction A) within the housing 2. By being able to float axially relative to the housing 2, the shroud 10 can fill a gap 7 between the housing 2 and the surface 5. The maximum size of the gap 7 across which the shroud 10 can extend is the amount by which the shroud 10 extends from the housing 2 when the shoulder 11 is in contact with the housing 2.
The expander unit 1 is mounted to the external surface 5 so that the bottom surface 12 of the shroud is in contact with the external surface, and the spring 9 is compressed against the external surface of the shroud 10. The anti-tamper means 8, 9 are then fully contained within the shroud 10. A user cannot gain access to the spring 9, without taking apart the expander unit 2, and so the anti-tamper means 8, 9 are protected by the shroud 10.
Referring to figure 3, in an alternative arrangement according to the invention, the shroud 10 has the same configuration and orientation to the shroud 10 in figure 2, but in this case, the shroud 10 is fixed to the external surface 5. The fixing means are a screw 15 that is screwed through the bottom surface 12 of the shroud 10. The spring 9 is protected within the shroud 10.
Figure 4 illustrates how, most preferably, the shroud may be pre-formed as part of the housing for an expander. The figures show a panel 17 in the form of a rear moulding 18, the rear moulding being the wall of the expander unit that faces the external surface. The panel is formed with a projecting shroud portion 19 that is fixed to the rear moulding 18 by frangible means 21 or other breakable/ removable means. The shroud 19 is in the form of a cap, and may be provided with a removable shoulder 20. Before use of the expander unit, the shroud 19 is separated from the rear moulding 18 by breaking the frangible means 21. The shroud is then fitted through the opening 22 in the rear moulding, and the shroud can be used to protect the anti-tamper means in this position.
The anti-tamper means preferably comprise a compressible component and a switch. The compressible component is generally a spring, and the switch is generally a microswitch.
A microswitch is generally a miniature electric switch that is actuated by a very small physical force, generally through the use of a tipping point mechanism. Microswitches have the advantages of being low cost and durable. However, it will be appreciated by a person of skill in the art that any type of mechanism that is capable of being activated when the expander unit is tampered with is suitable for use with the present invention.
The compressible component is generally a coiled spring, but it is obvious to a person of skill in the art that any component that is capable of at least partially extending between the expander unit and the surface to which the expander unit is mounted, and that can be somehow affected by an attempt to tamper with the expander unit, is suitable for use with the present invention. For example, the compressible component could also be a piece of compressible material such as a soft rubber, or the component could be compressible by means of a concertina mechanism.
The compressible means are at least partially compressed when the unit is mounted to the external surface.

Claims

An alarm apparatus comprising a housing (2), an anti-tamper means (3) comprising a compressible component (9) and a switch (8), said anti-tamper means being adapted for triggering an alarm when the alarm apparatus is removed from a surface it is fixed to and the compressible component (9) is allowed to relax, thereby triggering the switch (8), and a protective shroud (10) adapted to project outwardly from an opening in the housing of the alarm apparatus and positioned to protect the anti-tamper means by restricting user access to the anti-tamper means, wherein the shroud projects through a part of the housing and is arranged to be held captive by the housing yet able to float axially relative to the housing to enable the protective shroud means to project through the housing by a varying amount, wherein the shroud is mounted to project at least partly between part of the housing of the alarm apparatus and a surface to which the alarm apparatus is mounted, the shroud is in the form of a cap having a shoulder (11), the shoulder having an outer diameter that is larger than the diameter of the opening to prevent the shroud from being fully removed from the housing through the opening, wherein the shroud is mounted so that a surface of the bottom of the shroud is in contact with said surface to which the alarm apparatus is fixed to; characterised in that said compressible component is compressed against the other opposite surface of the bottom of the shroud when the alarm apparatus is mounted on the surface, and in that the shroud is arranged to be held captive by the housing yet able to float axially relative to the housing to enable the protective shroud means to project through the housing, towards said surface to which the apparatus is fixed, by a varying amount up to the amount by which the shoulder comes in contact with the housing.
An alarm apparatus as claimed in claim 1, wherein the alarm apparatus is an expander unit (1).
An alarm apparatus as claimed in claim 1, wherein the shroud fits at least partially around the anti-tamper means and has at least one hollow end.
An alarm apparatus as claimed in claim 1, wherein the shoulder is separable from the shroud.
An alarm apparatus as claimed in claim 4, wherein the shoulder is attached by a weakened portion (21) to the body of the shroud.
An alarm apparatus as claimed in any preceding claim, including a means for fixing the protective means to the surface on which the unit is mounted.
An alarm apparatus as claimed in any preceding claim, wherein at least part of the housing of the alarm apparatus is formed with a pre-formed shroud, and the shroud is separable from the housing.