EP0518685A2 - Dispositif d'alarme - Google Patents

Dispositif d'alarme Download PDF

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Publication number
EP0518685A2
EP0518685A2 EP92305419A EP92305419A EP0518685A2 EP 0518685 A2 EP0518685 A2 EP 0518685A2 EP 92305419 A EP92305419 A EP 92305419A EP 92305419 A EP92305419 A EP 92305419A EP 0518685 A2 EP0518685 A2 EP 0518685A2
Authority
EP
European Patent Office
Prior art keywords
assembly
cavity
pendulum
movement
magnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92305419A
Other languages
German (de)
English (en)
Other versions
EP0518685A3 (en
Inventor
John Dennis Macey
Christopher Russell Johnson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CQR SECURITY COMPONENTS Ltd
Original Assignee
CQR SECURITY COMPONENTS Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by CQR SECURITY COMPONENTS Ltd filed Critical CQR SECURITY COMPONENTS Ltd
Publication of EP0518685A2 publication Critical patent/EP0518685A2/fr
Publication of EP0518685A3 publication Critical patent/EP0518685A3/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/10—Monitoring of the annunciator circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H35/00—Switches operated by change of a physical condition
    • H01H35/14—Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch
    • H01H35/147—Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch the switch being of the reed switch type

Definitions

  • This invention relates to an alarm assembly and particularly, though not exclusively, to an alarm assembly of the type which is mounted on the exterior of a building.
  • Such alarm assemblies comprise an externally- mounted housing, which contains an audible device such as a bell or siren which is activated if the housing is tampered with, connected to an internally-contained control panel.
  • external alarm housings are susceptible to being disabled through physical attack followed by injection of compressed polyurethane foam into the cavity of the housing containing the audible device. The injected foam rapidly expands to fill the cavity and quickly dries as a solid mass which reduces the sound emitted by the audible device activated by the initial physical attack. In most cases the sound output is attenuated to such a degree that the audible device is rendered ineffective.
  • One approach to indicating tampering with alarm assemblies is an alarm assembly housing having a solid state electronic circuit incorporating an infra red beam transmitter and detector whereby foam, or any other object, entering the cavity breaks an infra red beam to generate an alarm signal.
  • a disadvantage of such an arrangement is that in time, dirt builds up over the infra red detector which may cause the infra red beam to be broken and cause a false alarm signal.
  • An alternative approach has been a mechanical system incorporating a unidirectionally movable flap connected to a microswitch mounted in the alarm bell housing in which ingress of foam into the housing moves the flap which trips the microswitch to generate an alarm signal at the host control panel.
  • a disadvantage of such a system is that it does not detect physical attack on the housing or the entry of foam from all directions.
  • an assembly comprising a housing defining a cavity occupied by an audible device and a tamper detection device comprising a member mounted for free movement in the cavity in more than one plane in response to a body entering the cavity or movement of the housing to permit an alarm signal to be generated.
  • the invention provides an alarm assembly which indicates any attempt at tampering orsabotage.
  • the body may be foam injected into the cavity.
  • the member may be in the form of a pendulum.
  • the member may be in the form of an upwardly-projecting stalk.
  • the member may be ordinarily in a rest position and moved to a disturbed position by entry of a body into the cavity or movement of the housing. Preferably, the member is moved by contact with the body.
  • the member is a pendulum it may be mounted for movement in two or more planes.
  • the pendulum is mounted to permit movement in any direction.
  • the pendulum may be supported by means of a ball mounted in a circular seat defined by a pendulum support.
  • Movement of the member may cause operation of a switch to permit an alarm signal to be generated.
  • the switch may be for example a reed switch.
  • the switch is generated by the proximity of the member.
  • the member may contain a magnet which switches the switch either on or off when the member is in the rest position and oppositely switches the switch when the member is in the disturbed position.
  • the member may be held into a metastable rest position.
  • the member is held in such a position by magnetic forces.
  • Afirst magnet may be mounted on the member which interacts with a second magnet mounted in the cavity.
  • the second magnet is ring shaped or comprises several magnets arranged to hold the member in the rest position.
  • the member may be held in the disturbed position until reset.
  • the member is held in the disturbed position by magnetic forces, and especially magnetic monitor interaction between the aforesaid first and second magnets.
  • a detection device comprising two members, the members being capable of magnetically repelling each other and being capable of relative movement between a rest position and a disturbed position, and a sensor arranged to sense when the members are in the disturbed position.
  • the strength of the magnetic repulsion and shape of the magnetic field can be adjusted to allow the device to be sensitive to positive disturbance forces of an appropriate magnitude or greater.
  • the sensor preferably actuates an alarm and the alarm and the device may be provided in a housing.
  • the alarm assembly 10 shown in Figs. 1-3 comprises a conventional housing (removed for clarity) which is attached to a back plate 12.
  • the back plate is in turn fixed to the exterior of a building.
  • the housing and back plate 12 together define a cavity which contains an audible device (not shown), such as a bell or siren, connected to a host control panel (also not shown).
  • the cavity also contains a tamper detection device 14.
  • the tamper detection device 14 comprises a pendulum 16 supported for free movement by a ball 18 mounted in a circular chamfered seat 20.
  • the pendulum is free to swing in for example in the plane of the paper, or at any angle to that plane below the seat 20.
  • the pendulum 16 comprises a vertically-mounted bar magnet 22 the polarity of which is indicated in the drawings, and fins 24-38 (36, 38 not shown) which extend outwardly from the magnet 22.
  • a ring-shaped magnet 40 is mounted below the pendulum 16.
  • the polarity of the magnet 40 is shown in the drawings and it will be seen that magnetic repulsion between the adjacent south poles of magnets 22 and 40 causes the pendulum to be maintained in the position shown in Figs. 1 and 2.
  • a proximity reed switch 42 is mounted below the pendulum 16.
  • the reed switch is co-axial with the ring magnet 40 and is connected by a cable 44 to a host control panel (not shown) which is typically mounted inside the building to which the alarm assembly housing is attached.
  • the pendulum assembly 16 When sufficient pressure is applied to the pendulum assembly 16, either by vibration of the housing or through the flow of injected polyurethane foam into the cavity, to overcome the centralising effect of the magnetic interaction between the magnets 22 and 40, the pendulum is displaced to the position ("the disturbed position") shown in Fig. 3. Although the pendulum 16 is shown as having moved in the plane of the paper it can move in any direction by virtue of the ball mounting 18, 20.
  • the fins 24-38 serve to increase the surface of area of the pendulum 16against which the flow of foam entering the cavity can act.
  • Movement of the pendulum to the position shown in Fig. 3 causes the reed switch to revert its open circuit state which signals to the host control panel a sabotage attempt on the alarm assembly.
  • Magnetic repulsion between the opposed poles of magnets 22 and 40 holds the pendulum 16 in the position shown in Fig. 3 maintaining the alarm signal until the pendulum 16 is manually re-set by an engineer to the position shown in Figs. 1 and 2.
  • the alarm assembly of the present invention is advantageous over known mechanical tampered detection devices for alarm assemblies in that vibration in most directions, or entry of flow into the cavity of the alarm assembly in any direction will be readily be detected by the pendulum, and that it is resistant to adverse environmental conditions.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
EP19920305419 1991-06-14 1992-06-12 Alarm assembly Withdrawn EP0518685A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9112878 1991-06-14
GB919112878A GB9112878D0 (en) 1991-06-14 1991-06-14 Alarm assembly

Publications (2)

Publication Number Publication Date
EP0518685A2 true EP0518685A2 (fr) 1992-12-16
EP0518685A3 EP0518685A3 (en) 1993-05-12

Family

ID=10696699

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920305419 Withdrawn EP0518685A3 (en) 1991-06-14 1992-06-12 Alarm assembly

Country Status (3)

Country Link
EP (1) EP0518685A3 (fr)
GB (2) GB9112878D0 (fr)
IE (1) IE67629B1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH699852A1 (it) * 2008-11-12 2010-05-14 Flii Albertolli Sa Dispositivo anti-intrusione per recinzioni.

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2366080A (en) * 2000-08-09 2002-02-27 Herga Electric Switch assembly

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012611A (en) * 1975-03-03 1977-03-15 Cega, Inc. Inertia switch for anti-intrusion sensing systems
DE8627987U1 (de) * 1986-10-21 1986-12-04 Sonax-Alarmanlagen GmbH & Co KG, 49477 Ibbenbüren Schutzgehäuse für einen akustischen Signalgeber
US4945347A (en) * 1988-03-17 1990-07-31 Perry John C Motion and orientation responsive device for seismic, intrusion, and tilt alarms and the like

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB688402A (en) * 1950-06-30 1953-03-04 Trist & Co Ltd Ronald Improvements relating to magnetic devices
GB741484A (en) * 1953-01-29 1955-12-07 John Kenrick Haynes Improvements in or relating to gas flow responsive electric switch devices
FR1410249A (fr) * 1963-06-18 1965-09-10 Garde-temps électrique, à pendule ou à oscillateur tourant, en particulier montre pour automobile
GB1010862A (en) * 1963-07-31 1965-11-24 Ass Elect Ind Improvements relating to electric switching devices responsive to abnormal level or flow conditions in a container
US3721956A (en) * 1971-02-08 1973-03-20 V Hamann Theft alarm operable by vibration
US4247847A (en) * 1978-08-16 1981-01-27 Sprague Electric Company Vibration-detecting intrusion alarm
US4227188A (en) * 1978-09-25 1980-10-07 Petersen Christian C Intrusion alarm control system
US4282518A (en) * 1979-07-09 1981-08-04 Bonner Edgar L Vibration responsive door alarm
NL8100236A (nl) * 1980-05-02 1981-12-01 Beta Bv Door een mediumstroom bediende schakelinrichting.
CA1167132A (fr) * 1980-10-16 1984-05-08 Aaron V. Farr Detecteur de vitesse de descente
US4381504A (en) * 1981-01-30 1983-04-26 Fifth Dimension Inc. Switch and alarm system responsive to sudden movement, angular tilt and vibration
US4385288A (en) * 1981-05-04 1983-05-24 Fifth Dimension, Inc. Motion responsive alarm system
DE3338287C1 (de) * 1983-10-21 1985-05-02 W. Günther GmbH, 8500 Nürnberg Beschleunigungs- und Verzoegerungs-Sensor
US4575713A (en) * 1984-04-23 1986-03-11 Piper Bert W Disturbance alarm
DE8806240U1 (de) * 1988-05-11 1988-08-18 W. Günther GmbH, 8500 Nürnberg Beschleunigungs- oder Verzögerungs-Sensor
GB2225470A (en) * 1988-10-14 1990-05-30 Grant Design Limited Alarm tamper detection device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012611A (en) * 1975-03-03 1977-03-15 Cega, Inc. Inertia switch for anti-intrusion sensing systems
DE8627987U1 (de) * 1986-10-21 1986-12-04 Sonax-Alarmanlagen GmbH & Co KG, 49477 Ibbenbüren Schutzgehäuse für einen akustischen Signalgeber
US4945347A (en) * 1988-03-17 1990-07-31 Perry John C Motion and orientation responsive device for seismic, intrusion, and tilt alarms and the like

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH699852A1 (it) * 2008-11-12 2010-05-14 Flii Albertolli Sa Dispositivo anti-intrusione per recinzioni.

Also Published As

Publication number Publication date
GB2258934B (en) 1995-05-10
IE921904A1 (en) 1992-12-16
GB9112878D0 (en) 1991-07-31
EP0518685A3 (en) 1993-05-12
GB9212440D0 (en) 1992-07-22
IE67629B1 (en) 1996-04-17
GB2258934A (en) 1993-02-24

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