| (19) |
 |
|
(11) |
EP 0 518 685 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
12.05.1993 Bulletin 1993/19 |
| (43) |
Date of publication A2: |
|
16.12.1992 Bulletin 1992/51 |
| (22) |
Date of filing: 12.06.1992 |
|
| (51) |
International Patent Classification (IPC)5: G08B 29/10 |
|
| (84) |
Designated Contracting States: |
|
BE DE ES FR GB GR NL PT SE |
| (30) |
Priority: |
14.06.1991 GB 9112878
|
| (71) |
Applicant: CQR SECURITY COMPONENTS LIMITED |
|
Wirral,
Merseyside L46 4TH (GB) |
|
| (72) |
Inventors: |
|
- Macey, John Dennis
Willaston,
Cheshire (GB)
- Johnson, Christopher Russell
Wallasey,
Merseyside (GB)
|
| (74) |
Representative: Dempster, Benjamin John Naftel et al |
|
Withers & Rogers
4 Dyer's Buildings,
Holborn
London EC1N 2JT
London EC1N 2JT (GB) |
|
| |
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(57) s An alarm assembly 10 comprises a housing attached to a back plate 12 to define
a cavity occupied by a bell or siren and a tamper detection device. The tamper detection
device 14 comprises a member 16 mounted for free movement in the cavity in more than
one direction in response to a body entering the cavity or movement of the housing.
The member 16 comprises a magnet 22 which is repelled by another magnet 40 so as to
be movable between a metastable rest position and a disturbed position. A sensor 42
senses when the member 10 is in the disturbed position and causes the bell or siren
to be set off.