GB2401992A

GB2401992A - Alarm call point

Info

Publication number: GB2401992A
Application number: GB0311391A
Authority: GB
Inventors: John Francesco Bourne; Christopher Marti Stringfellow; Neil John Morris; Karl Andrew Vondrak
Original assignee: KAC Alarm Co Ltd
Current assignee: KAC Alarm Co Ltd
Priority date: 2003-05-17
Filing date: 2003-05-17
Publication date: 2004-11-24
Anticipated expiration: 2023-05-17
Also published as: NO332652B1; EP1627368A1; WO2004102502A1; EP1627368B1; GB0311391D0; GB2401992B; TW200508997A; NO20055994L; MY137917A

Abstract

A call point has a chassis 10, a displaceable element 11 movable between set and activated positions so as to trigger an alarm, a flag 52 to provide a visual indication of such activation and a cover 12. The displacement element 11 and flag 52 are operatively associated with the cover, in that removal of the cover from the chassis 10 results in activation of the call point and the provision of a visual indication thereof. A key 26 is used to reset the element 11 back to its original position.

Description

240 1 992 PATENTS ACT 1977 A10886GB-MNS Title: Call Points

Description of Invention

This invention relates generally to alarm call points, with the term "call point" being used to refer to a manually-operable alarm device of the kind which is activated by user, in response to a fire or other such incident.

Such call points, in use, form part of an alarm system, with it commonly being the case that a number of call points are used, in a given system, at various locations in a building, for example.

Historically, call points have often been of the "break-glass" type, in which a sheet of glass or other frangible-type material must be broken, either manually or with the aid of a certain tool, so as to actuate a switch in the call point which, in term, causes the alarm to sound.

Alternative arrangements include manually-operable pressure plates that simply move (but do not break) in response to manual pressure.

Whether a particular call point is of the first (frangible) or second (non- frangible) type, a widely-accepted requirement is that unauthorized access to the internal components of the call point should be restricted, for evident safety and functional reasons.

With that in mind, it is an object of the present invention to provide an improved call point that overcomes at least some of the perceived drawbacks of

the call points of the prior art.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided a call point having a chassis, a displaceable element movable between set and activated positions so as to trigger an alarm, a flag to provide a visual indication of such activation and a cover, the displacement element and flag being operatively associated with the cover, in that removal of the cover from the chassis results in activation of the call point and the provision of a visual indication thereof.

The displaceable element may be biased (perhaps resiliently-biased) towards the activated position, the cover having an engagement part which, when the cover is attached to the chassis, restricts movement of the displaceable element towards said activated position.

The displaceable elements may comprise a plate, an edge of which, in the set position, may bear upon an engagement part of the cover.

The plate may be deformable, such that inwardly-directed pressure exerted thereupon allows the edge thereof to move free of the engagement part, thus allowing the plate to move towards the activated position.

The flag may be integral with or attached to the displaceable element.

Preferably, the flag comprises a part of the displaceable element which is visually distinct from the remainder thereof.

The cover may be mounted on the chassis such that limited sliding movement therebetween may be effected.

_ The chassis may have a catch which engages with the cover to restrict said sliding movement.

Preferably, the catch is releasable using an appropriately configured key.

The catch may comprise a resilient limb, with the key, in use, preferably being operative to urge part of the limb out of engagement with the cover.

The displaceable element may be provided with a restraining formation which, when the displaceable element is in the activated position, is operative to restrict movement of the element back towards the set position.

The restraining formation may comprise a protrusion, which in use, may abut against a co-operating formation of the chassis.

Preferably, the co-operating formation comprises a resilient finger.

Sliding movement of the cover may allow the displaceable element to move between set and test positions. An appropriately configured key may be required to allow movement of the displaceable element towards the test position, although the key may not be so required to return the element to the set position.

In accordance with a second aspect of the present invention, there is provided an alarm call point having a chassis, a displaceable element movable between set and test positions so as to test the alarm and a cover, the cover being mounted for sliding movement on the chassis and being operatively associated with the displaceable element such that an alarm test procedure may be invoked by bringing about sliding movement of the cover.

The invention, in its second aspect, may comprise one or more of the features described in relation to the first aspect, or elsewhere herein.

In accordance with a third aspect of the present invention, there is provided a trigger mechanism for a call point comprising a displaceable element adapted for movement, in use, between set and activated positions so as to trigger an alarm, a flag to provide a visual indication of such activation and a cover, the displaceable element and flag being operatively associated with the cover whereby removal of the cover from a chassis of the call point results in activation of the call point and the provision of a visual indication thereof.

The invention, in its third aspect, may comprise one or more of the features set out in the preceding paragraphs, or elsewhere herein.

Brief Description of the Drawings

Specific but non-limiting embodiments of the various aspects of the present invention will now be described in greater detail, but strictly by way of example only, by reference to the accompanying drawings, of which: Figure 1 is an exploded view of the principal components of a call point; Figures 2A, 2B and 2C are perspective views of a call point chassis; Figures 3A and 3B are perspective views of a call point cover; Figure 4 is a perspective view of a displaceable (non-frangible) element, or pressure plate; Figures 5A and 5B are perspective illustrations of a call point release key; and Figures 6A and 6B are perspective illustrations of a spring biased- plunger.

Detailed Description and Best Mode of the Invention Referring first to Figure 1, a call point assembly (shown in exploded form) includes a chassis 10 and a displaceable element 11 which, when the call point is assembled, lies between the chassis 10 and a removable cover 12. In place of the displaceable element 11, a frangible plate 13 (made, for example, of glass) may be provided, in conjunction with an optional graphics label 14 which may be adhered thereto. It should be understood, however, that the present invention relates principally to non-frangible type call points, with the glass plate 13 and graphics label 14 thus being shown simply for the sake of completeness.

Abridged lid 15 may also be provided which, as shown in Figure 2A, is pivotally secured to an upper part of the chassis 10, so as to provide protection against inadvertent activation of the call point, in generally conventional manner. The lid 15, for the avoidance of doubt, does not form part of the present invention.

Disposed towards the rear of the call point chassis 10 is a printed circuit board (PCB) 16, to which are mounted appropriate electronic and electrical components, again in generally conventional manner. In this example, an LED 17 is provided, which illuminates in the event of the call point being activated.

Also mounted to the PCB 16 is a microswitch assembly 18 having an actuating element 19 disposed, when the call point is assembled, for engagement with a spring-biased plunger 20, shown in more detail in Figures 6A and 6B. The plunger 20 is attached to the PCB 16 by way of slotted engagement between an engagement head 21 and a slot 22 provided in an edge portion of the PCB 16, with a coil (compression) spring 23 being disposed between the plunger 20 and a spring-holding lug 24 provided as part of a PCB cover 25. It should be understood, in that regard, that movement of the plunger 20 in line with the principal axis of the spring 23 causes the switch actuating element 19 to be depressedlreleased, thus activating/resetting an associated alarm system, depending upon the system's particular configuration.

Although not forming part of the call point assembly itself, there is also provided a release/ test key 26 which, as explained in more detail hereinafter, serves to release the cover 12 from the chassis 10, for resetting and testing purposes. The key 26 is illustrated in more detail in Figures 5A and 5B.

The PCB 16 is provided with at least one (in this case two) edge connectors 27 which are adapted for electrically-conducting engagement with a removable connector 28, by way of a push-fit engagement, to facilitate call point installation. This is described in more detail in our co-pending patent application and does not form part of the present invention.

As explained above, the plunger 20 is slidably receiveLwithin a slot 22 of the PCB 16 which, in turn, is attached, by way of a snap-fit engagement, to the PCB cover assembly 25. When assembled, this sliding engagement is assisted by a pair of plunger runners 213, which lie either side of guide ribs 22a provided on an inside surface of the chassis 10. The spring 23 is thus trapped between the plunger 20 and an inwardly- facing surface of the holding lug 24 meaning, when assembled, that a nose 29 of the plunger 20 will be disposed near - but slightly raised from - a V-shaped recess 30 provided in an edge 31 of the chassis 10.

This nose 29 is received by a correspondingly-configured V-shaped recess 32 provided in an edge 33 of the displaceable element 11. The element 11, when the call point is assembled, lies within a holding area 34 of the chassis 10, the area 34 being defined, towards a lower part call point, by inturned L- shaped formations 35 and side walls 36. Runner ribs 37 are also provided, whereby the displaceable element 11 may undergo limited sliding movement, generally in the plane of the chassis 10, against the action of the spring 23.

Downward movement of the element 11, under the bias of the spring 23, is restricted by engagement of a lower edge 38 of the element 11 with the inturned formations 35. It will be understood, however, that the element it is free to move - albeit to a limited extent - in an upwards direction, against the action of the spring 23, into an aperture 39 provided in the chassis.

As explained briefly above, the displaceable element l l is held in place by the cover 12 which is mounted to the chassis 10 by engagement of cover arms 40 with outer surfaces of the chassis side walls 36. The cover arms 40 are configured so as to permit limited sliding movement of the Ushaped cover 40 along runner tracks 41 of the chassis 10, with inwardly facing lugs 42, provided on the cover arms 40, serving to restrict the degree of permitted sliding movement, by abutment thereof with stop walls 43 of the chassis. Thus, at one extreme, the distal ends of the cover arms 40 will lie in contact with abutment surfaces 44 Df the chassis, although sliding movement of the cover, in a generally downwards direction, allows the cover 12 to become slightly separated from these abutment surfaces, with the degree of separation being limited by the presence of the stop walls 43 of the chassis.

With the cover 12 in place, the lower edge 38 of the displaceable element 11 rests on a pair of engagement posts 50, with this engagement restricting movement of the displaceable element 11 towards the inturned formations 35, under the action of the spring 23. This condition corresponds to a "set" alarm condition, in which the microswitch actuator 19 is depressed by engagement thereof with a ramped lug 51 of the plunger 20. Thus, the displaceable element 11 is trapped between the engagement posts 50 and the spring-biased nose 29 of the plunger 20. In this position, an alarm activation flag 52, in the form of a coloured band or strip, provided integrally with an upper portion of the element 11, is concealed from view by an upper housing assembly 53 ofthe chassis 10.

The cover 12 is held in position as a result of a snap-fitting engagement between a pair of resilient, barbed limbs 73 and ramped shoulder formations 54 provided on the cover 12. Thus, the cover 12 is restrained from sliding movement, relative to the chassis 10 which, in turn, means that the displaceable element 11 is trapped within the assembly.

As explained above, this state of affairs relates to an "alarm set" l O condition, with it being necessary, to activate the alarm, to allow the plunger 20 to move relative to the microswitch actuator 19 which, in turn, requires movement of the displaceable element 11 that is held in abutting relationship with the nose 29 of the plunger 20. In order to activate the alarm, the displaceable element, which is flexible but non- frangible, is depressed, using manual (finger) pressure in an inwards direction, into the body of the call point.

This causes the element 11 to flex inwardly, allowing the lower edge 38 thereof to move free of the engagement posts 50 of the cover 12 and thus allowing the plate 11 to move downwardly, under the influence of the springers, until the edge 38 of the element 11 comes into contact with the inturned walls 35 of the chassis 10.

This generally downwards movement of the element 11 allows the plunger 20 also to move in that direction, which in turn changes the condition of the microswitch actuator 19, so as to cause the alarm, to which the call point is connected, to be triggered. In hand with that, the flag 52, having dropped free of the housing assembly 53, becomes visible, thus providing a visual indication that the call point has been activated.

The displaceable element ll is also provided with a pair of ramped formations 68 which, in use, bear upon the concave surface 55 of the chassis 10, so as to encourage deformation of the element 11 to occur towards a lower part thereof, and thus to facilitate the engagement between the parts 56 and 57, by hindering any such inward flexing towards the upper part of the element 11.

In this (activated) condition, the displaceable element 11 is trapped between the cover 12 and a somewhat concave surface 55 of the call point chassis. The element 11 is provided, on its rear surface, with a shelflike protrusion 56 which, when the element l l adopts its inwardly-flexed condition, mates with the distal end of a resilient finger 57, thus preventing upward sliding movement of the element 11. Thus, the element 11 is prevented from upwards movement by engagement of the protrusion 56 with the finger 57, with it not being possible to disengage these components without the element 11 returning to its unflexed (flat) condition. This, however, is prevented by the engagement posts 50 which now press upon a lower part 58 of the element 11, keeping it in its flexed condition.

It will thus be appreciated that to release the element 11, it is first necessary to release the cover 12.

To release the cover 12 from the chassis 10, it is necessary to disengage the resilient limbs 73 from the ramped catches 54 of the cover 12. To effect this, the key 26 iintroduced through a keyhole 59, so that ramped key surfaces may be brought into sliding engagement with barbed formations 61 of the resilient limbs 73. This engagement results in the resilient limbs 73 being deflected inwardly (i.e. into the body of the call point) which, in turn, frees the barbs 61 from their engagement with the engagement shoulders 54 of the cover 12. At that point, the cover 12 is free to move in a generally downwards direction, with this movement being assisted by the sprung-fork nature of the key 26. Specifically, referring to Figure 5A, it can be seen that the key 26 comprises a pair of splayed but resilient limbs 62 which are able to flex away from each other upon introduction of the key 26 into the keyhole 59, with a somewhat hexagonal guide element 63 assisting in this splaying separation.

The key is also provided with a pair of shoulder-like catch formations 64 which, once the key is fully introduced, engage with a pair of suitably configured engagement elements 65 provided on the cover 12. This engagement allows the key to be used to pull the cover 12 away from (and generally downwardly in relation to) the chassis 10, subsequent to which the key may be removed.

To reset the call point, all that is required is for the cover 12 to be slid, under manual pressure, in a generally upwards direction, whereby the engagement posts 50 will come into contact with the lower edge 38 of the element l l, thus causing the element 11 to move upwardly, with the cover.

Continued movement of this type will eventually result in re-engagement of the barbed limbs 73 with the engagement shoulders 54 of the cover, thus snap- fitting the cover back into a "set" position ready for re-activation.

In order to invoke a test procedure, it is also necessary to effect sliding movement of the cover, to allow the displaceable element 11 to move downwardly, under the action of the spring 23. To do this, all that is required is for the key to be introduced into the keyhole 59, thus freeing the cover 12 from the barbed chassis clips 73, and allowing the cover 12 to move downwardly, in hand with the element 11. During this operation, it will be understood that no inward deformation of the element 11 need occur, meaning that, throughout the sliding movement of the element 11, the lower edge 38 may remain in abutting contact with the engagement posts 50. Downward travel of the cover 12 is limited by engagement of the cover lugs 42 with the upstanding stop walls 43 of the chassis 10, although the degree of movement to which this corresponds is sufficient to allow a change to occur in the condition of the microswitch 19, thus allowing a test procedure to be initiated. To reset the call point, following a test procedure, all that is required is for the cover 12 to be moved back, in a generally upwardly direction, against the action of the spring 23, in the same manner as that described above.

It will be appreciated from the foregoing that the operative relationship between the cover 12 and the displaceable element l l allows the call point of the present invention to operate in a substantially tamper proof manner, as it is very difficult - if not impossible - to remove the cover 12 from a "set" call point without allowing the displaceable element 11 to be released under the influence of the spring 23. Thus, tampering is likely to result not only in activation of the alarm itself but also in a visual indication of that fact, by virtue of the flag 52 coming into view, under the action of the spring 23.

What will also be understood is that the call point testing and reset procedure is largely simplified, in that a single key is required both to perform the test procedure and to remove the cover 12 from the call point chassis. It should be noted, in that regard, that the end of the key 26 remote from the splayed limbs 62 has a hooked configuration so that it may be used to test other call points currently on the market. This hooked configuration plays no part in the present invention, with it thus being clear that just one end of the key is needed to perform the reset and cover-release operations. It should also be noted that the key is only, in fact, required to release the cover 12 from the chassis 10; the key ismot needed to reset the mechanism, as all that is required is for sliding movement of the cover 12 to be effected, which can be done manually, by a user.

In the present specification "comprises" 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

1. A call point having a chassis, a displaceable element movable between set and activated positions so as to trigger an alarm, a flag to provide a visual indication of such activation and a cover, the displacement element and flag being operatively associated with the cover, in that removal of the cover from the chassis results in activation of the call point and the provision of a visual indication thereof.

2. A call point according to claim 1 wherein the displacement element is biased towards the activated position, the cover having an engagement part which, when the cover is attached to the chassis, restricts movement of the displaceable element towards said activated position.

3. A call point according to claim 1 or claim 2 wherein the displaceable element comprises a plate, an edge of which, in the set position, bears upon an engagement part of the cover.

4. A call point according to claim 3 wherein the plate is deformable, such that inwardly-directed pressure exerted thereupon allows the edge thereof to move free of the engagement part, thus allowing the plate to move towards the activated position.

5. A call point according to any one of the preceding claims, wherein the flag is integral with or attached to the displaceable element.

6. A call point according to any one of the preceding claims, wherein the flag comprises a part of the displaceable element which is visually distinct from the remainder thereof.

7. A call point according to any one of the preceding claims, wherein the cover is mounted on the chassis such that limited sliding movement therebetween may be effected. s

8. A call point according to claim 7 wherein the chassis has a catch which engages with the cover to restrict said sliding movement.

9. A call point according to claim 8 wherein the catch is releasable using an appropriately-configured key.

10. A call point according to claim 8 or claim 9 wherein the catch comprises a resilient limb and wherein the key, in use, is operative to urge part of the limb out of engagement with the cover.

11. A call point according to any one of the preceding claims wherein the displaceable element is provided with a restraining formation which, when the displaceable element is in the activated position, is operative to restrict movement of the element back towards the set position.

12. A call point according to claim 11 wherein the restraining formation comprises a protrusion which, in use, abuts against a co-operating formation of the chassis.

13. A call point according to claim 12 wherein the co-operating formation comprises a resilient finger.

14. A call point according to any one of the preceding claims wherein sliding movement of the cover allows the displaceable element to move between set and test positions.

15. A call point according to claim 14 wherein an appropriately configured key is required to allow movement of the displaceable element towards the test position, but wherein the key is not so required to return the element to the set position.

16. An alarm call point having a chassis, a displaceable element movable between set and test positions so as to test the alarm and a cover, the cover being mounted for sliding movement on the chassis and being operatively associated with the displaceable element such that an alarm test procedure may be invoked by bringing about sliding movement of the cover.

17. A trigger mechanism for a call point comprising a displaceable element adapted for movement, in use, between set and activated positions so as to trigger an alarm, a flag to provide a visual indication of such activation and a_ i cover, the displaceable element and flag being operatively associated with the cover whereby removal of the cover from a chassis of the call point results in activation of the call point and the provision of a visual indication thereof.

18. A call point substantially as hereinbefore described and/or as shown in the accompanying drawings.

19. A trigger mechanism for a call point substantially as hereinbefore described and/or as shown in the accompanying drawings.

20. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.