EP0011451A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Security alarm systems
Assignee: Individual
•
Filing: 1979-11-09
•
Granted: —
•
Expires: 1999-11-09
Abstract
Abstract An alarm system uses piezo electric crystals (2) which when vibrated produce an electrical signal that can be amplified and used to generate an alarm or perform some other action. Each crystal and amplifier (3) are in a sensor unit (1) with a latch circuit (7) and indicator (9). Vibrations latch the indicator on, and the signal is also passed to a central control unit (15). This responds with an alarm or other action, relay (25) controlled, and an energised indicator (24). The control unit also has a re-set facility (20) and an indicator (22) for showing that the system is active. If the cable connection between any sensor unit and the control unit is cut, the effect at the control unit is that of a disturbed sensor unit.
Inventors
- 👤 Jack Youens
- 👤 Rodney Edward Charles White
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:48
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/12; G08B13/126; G08B13/16; G08B13/1654
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
44 words
A security alarm system comprising a piezo electric crystal responsive to stress to produce an electrical signal, amplifying means for such a signal, and means responsive to the amplified signal to give an indication and/or perform a physical action when the crystal is vibrated.
Claim 2
Dependent Claim
44 words
A security alarm system comprising a piezo electric crystal responsive to stress to produce an electrical signal, amplifying means for such a signal, and means responsive to the amplified signal to give an indication and/or perform a physical action when the crystal is vibrated.
Claim 3
Dependent Claim
28 words
A system as claimed in claim 1, wherein the amplified signal is applied to the responsive means via a latch circuit which stays latched after vibrations have ceased.
Claim 4
Dependent Claim
35 words
A system as claimed in claim 1 or 2, wherein the amplifier has associated sensitivity adjusting means whereby only vibrations of a selected magnitude and above can generate a signal to activate the responsive means.
Claim 5
Dependent Claim
34 words
A system as claimed in claim 1, 2 or 3, wherein the crystal and amplifying means are in a sensor unit remote from, and cable connected to, a control unit housing the responsive means.
Claim 6
Independent Claim
29 words
A system as claimed in claims 2 and 4, wherein the sensor unit also contains the latch circuit and an indicator governed thereby to show if vibrations have occurred.
Claim 7
Dependent Claim
23 words
A system as claimed in claim 4 or 5, wherein the control unit has an indicator to show whether the system is active.
Claim 8
Dependent Claim
23 words
A system as claimed in claim 4,5 or 6,wherein at least part of the responsive means is an indicator on the control unit.
Claim 9
Dependent Claim
26 words
A system as claimed in claim 7, wherein means are provided for neutralising another part of the responsive means, after activation, without affecting the indicator part.
Claim 10
Independent Claim
31 words
A system as claimed in any one of claims 4 to 8, wherein the control unit has reset means by which the system can be restored to its active, pre-vibrated state.
Claim 11
Independent Claim
44 words
A system as claimed in any one of claims 4 to 9, wherein the control unit and the cable connection are such that if the latter is cut or otherwise removed while the system is active there is a response from said responsive means.
Claim 12
Independent Claim
27 words
A system as claimed in any preceding claim, wherein there is a plurality of crystals and associated amplifying means connected in parallel to common said responsive means.
Claim 13
Dependent Claim
14 words
A security alarm system substantially as hereinbefore described with reference to the accompanying drawing.
Claim 14
Dependent Claim
14 words
A security alarm system substantially as hereinbefore described with reference to the accompanying drawing.
References Cited (Backward Citations)
US3863250A
Cited
DE2611692A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.