GB1397796A - Intruder alarm systems - Google Patents
Intruder alarm systemsInfo
- Publication number
- GB1397796A GB1397796A GB2267072A GB2267072A GB1397796A GB 1397796 A GB1397796 A GB 1397796A GB 2267072 A GB2267072 A GB 2267072A GB 2267072 A GB2267072 A GB 2267072A GB 1397796 A GB1397796 A GB 1397796A
- Authority
- GB
- United Kingdom
- Prior art keywords
- flash
- bulbs
- trigger
- photo
- pulse
- 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
- G08B1/00—Systems for signalling characterised solely by the form of transmission of the signal
- G08B1/08—Systems for signalling characterised solely by the form of transmission of the signal using electric transmission ; transformation of alarm signals to electrical signals from a different medium, e.g. transmission of an electric alarm signal upon detection of an audible alarm signal
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Burglar Alarm Systems (AREA)
Abstract
1397796 Photo-electric burglar alarms A L LITMAN 15 May 1972 22670/72 Heading G1A [Also in Division G4] A burglar alarm comprises a plurality of sources (e.g. flash-bulbs 15A, 15B) of visible or non-visible light each operated in response to an intrusion to generate a pulse and at least one detector capable of responding to said pulse but being substantially unresponsive to continuous lighting or pulsed lighting of lower level. As described, each source comprises a cube of four flash-bulbs 15A, 15B triggered in pairs by means of pyrotechnic initiators operated by firing pins 17A, 17B in response to the impact of a lever 18 powered by a spring 19 when a trigger 20 is released when tension is applied to a chain 11 due to opening of a window or actuation of a treadle. The flash-bulbs 15A, 15B may be in optical communication with a single central station or may irradiate a plurality of receivers each operating further flash-bulbs so as to provide a light-relay system. Fig.4 shows such a receiver in which the ambient light on a photo-cell 25 is insufficient to trigger a thyristor 28, but when a flash-bulb 15A, 15B is fired as the result of an intrusion, the resulting electrical pulse will pass capacitor 26, trigger thyristor 28 and operate an alarm 32 or a further flash-bulb 33. In Fig.5 (not shown) a photo transistor is employed which turns on two further transistors so as to feed a circuit similar to that shown in Fig.4. The system may operate with infrared by use of optical filters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2267072A GB1397796A (en) | 1972-05-15 | 1972-05-15 | Intruder alarm systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2267072A GB1397796A (en) | 1972-05-15 | 1972-05-15 | Intruder alarm systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1397796A true GB1397796A (en) | 1975-06-18 |
Family
ID=10183204
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2267072A Expired GB1397796A (en) | 1972-05-15 | 1972-05-15 | Intruder alarm systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1397796A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2224146A (en) * | 1988-10-22 | 1990-04-25 | Roy Kenneth Hammond | Intruder alarm system |
-
1972
- 1972-05-15 GB GB2267072A patent/GB1397796A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2224146A (en) * | 1988-10-22 | 1990-04-25 | Roy Kenneth Hammond | Intruder alarm system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PLNP | Patent lapsed through nonpayment of renewal fees |