GB1230373A - - Google Patents
Info
- Publication number
- GB1230373A GB1230373A GB1230373DA GB1230373A GB 1230373 A GB1230373 A GB 1230373A GB 1230373D A GB1230373D A GB 1230373DA GB 1230373 A GB1230373 A GB 1230373A
- Authority
- GB
- United Kingdom
- Prior art keywords
- detector
- bias
- alarm
- proximity
- oscillator
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/26—Electrical actuation by proximity of an intruder causing variation in capacitance or inductance of a circuit
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Burglar Alarm Systems (AREA)
Abstract
1,230,373. Intruder alarms, proximity detectors. K. G. R. SMITHYES. April 3, 1968 [Jan. 3, 1967], No. 391/67. Heading G1N. [Also in Division G4] A burglar alarm system is also triggered by a proximity detector in the alarm casing to prevent tampering with the unit. As shown the detector comprises a Colpitts oscillator including T9, an antenna K and a coil L3 coupled to L4 to provide cut-off bias to T10. Approach of a conducting body stops the oscillator and removes bias from T10 which conducts to provide an output pulse through C16. Alternatively a capacitative bridge or inductive detector may be used. The associated alarm may be light beam, contact type, radar detector, or pressurized room type.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB39167 | 1967-01-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1230373A true GB1230373A (en) | 1971-04-28 |
Family
ID=9703585
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1230373D Expired GB1230373A (en) | 1967-01-03 | 1967-01-03 |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1230373A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2152721A (en) * | 1984-01-14 | 1985-08-07 | John Michael Loftus | Intruder alarm apparatus |
| US4760295A (en) * | 1985-04-17 | 1988-07-26 | Geoquip Security Systems Ltd. | Vibration-sensitive transducer |
-
1967
- 1967-01-03 GB GB1230373D patent/GB1230373A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2152721A (en) * | 1984-01-14 | 1985-08-07 | John Michael Loftus | Intruder alarm apparatus |
| US4760295A (en) * | 1985-04-17 | 1988-07-26 | Geoquip Security Systems Ltd. | Vibration-sensitive transducer |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed |