US3774191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity alarm circuit for entrance annunciators
Assignee: EL SIG LAB Inc
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Filing: 1972-02-14
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Granted: 1973-11-20
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Expires: 1992-02-14
Abstract
Abstract A household alarm circuit, when switched on during night hours, responds to the touch or proximity of a human body to the house door knob or lock by sounding the existing door bell or chime. The alarm circuit utilizes the low voltage supply for the door chime and has a proximity sensing lead for connection to the striker plate of the door latch. When the door knob or lock is approached or touched, the alarm circuit repeatedly sounds the door chime. The alarm circuit includes a rectifier for connection to the AC door chime supply, a transistor cut off by a potential change transmitted to its gate by the sensing lead, an SCR switch closed by the transistor, and a relay in series with the SCR switch with a contact for closing the door chime circuit.
Inventors
- 👤 R Enemark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:10
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/22; G08B13/26; H; H03; H03K; H03K17/00; H03K17/94; H03K17/945; H03K17/955; H03K17/96; H03K17/962
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
198 words
A proximity circuit for connection between the key terminals of an annunciator circuit carrying alternating current comprising: electronic valve meAns for sensing an adjacent mass to alter the conductive state of the valve means, a storage capacitor, a rectifier having two terminals for connection to the key terminals and for rectification of the alternating currant, and having a charging circuit to the storage capacitor, said two rectifier terminals comprising the only connection from the proximity circuit to the annunciator circuit, and controlled switching means connected to the rectifier having a power supply connection from the capacitor and input means connected to said valve means, the switching means having a switching element connected across the rectifier and across the connection to the key terminals and being responsive to the change of state of the valve means to close a circuit between the key terminals each time the valve means alters state thereby to actuate the annunciator and disable said charging circuit allowing discharge of the storage capacitor and interruption of power supply to the switching means until the charging circuit is restored, whereby successive charge and discharge cycles of the storage capacitor cause repeated actuation cycles of the annunciator.
Claim 2
Dependent Claim
198 words
A proximity circuit for connection between the key terminals of an annunciator circuit carrying alternating current comprising: electronic valve meAns for sensing an adjacent mass to alter the conductive state of the valve means, a storage capacitor, a rectifier having two terminals for connection to the key terminals and for rectification of the alternating currant, and having a charging circuit to the storage capacitor, said two rectifier terminals comprising the only connection from the proximity circuit to the annunciator circuit, and controlled switching means connected to the rectifier having a power supply connection from the capacitor and input means connected to said valve means, the switching means having a switching element connected across the rectifier and across the connection to the key terminals and being responsive to the change of state of the valve means to close a circuit between the key terminals each time the valve means alters state thereby to actuate the annunciator and disable said charging circuit allowing discharge of the storage capacitor and interruption of power supply to the switching means until the charging circuit is restored, whereby successive charge and discharge cycles of the storage capacitor cause repeated actuation cycles of the annunciator.
Claim 3
Dependent Claim
26 words
A circuit according to claim 1 wherein said rectifier comprises a bridge having alternating current inputs for connection to said key terminals and direct current outputs.
Claim 4
Dependent Claim
16 words
A circuit according to claim 2 wherein the storage capacitor is connected between the bridge outputs.
Claim 5
Dependent Claim
16 words
A circuit according to claim 2 wherein the valve means is connected between the bridge outputs.
Claim 6
Dependent Claim
16 words
A circuit according to claim 2 wherein the switching means is connected between the bridge outputs.
Claim 7
Dependent Claim
16 words
A circuit according to claim 2 wherein the switching means is connected between the bridge inputs.
Claim 8
Dependent Claim
26 words
A circuit according to claim 6 wherein the switching means comprises a relay coil connected between the bridge outputs with a contactor connected between the inputs.
Claim 9
Dependent Claim
24 words
A circuit according to claim 1 wherein the switching means comprises a first solid state switch having primary electrodes connected between the bridge outputs.
Claim 10
Dependent Claim
20 words
A circuit according to claim 8 wherein the switching means includes a relay coil in series with said primary electrodes.
Claim 11
Dependent Claim
33 words
A circuit according to claim 8 wherein the switching means comprises a second solid state switch having a control electrode connected to one of the primary electrodes of the first solid state switch.
Claim 12
Dependent Claim
107 words
A circuit according to claim 1 wherein the switching means comprises a switching device and a second electronic valve for controlling closing of the switching device, characterized by a second storage capacitor connected to the second valve and having a second charging path from the rectifier and a discharge path through the second valve with a substantially longer time constant than the discharge cycle of the first said storage capacitor, the second valve means being responsive to discharge of the second storage capacitor to hold the switching device closed thereby to cause repeated cycling of the first storage capacitor during the time constant of the second capacitor.
Claim 13
Dependent Claim
16 words
A circuit according to claim 11 wherein said switching device comprises a solid state latching switch.
Claim 14
Dependent Claim
18 words
A circuit according to claim 12 wherein the latching switch and the second electronic valve are in series.
Claim 15
Dependent Claim
91 words
A circuit according to claim 8 characterized by a second capacitor connected to a second electronic valve in series with the first solid state switch, said second valve forming a discharge path for the second capacitor with a time constant substantially longer than the discharge cycle of the storage capacitor, and said second valve being responsive to discharge of the second capacitor to complete the power supply connection to the first solid state switch, thereby to cause repeated cycling of the storage capacitor during the time constant of the second capacitor.
Claim 16
Dependent Claim
26 words
A circuit according to claim 14 characterized by a manual switch operable to disable said second electronic valve and allow unlimited cycling of the storage capacitor.
Claim 17
Dependent Claim
36 words
A circuit according to claim 1 wherein said electronic valve means comprises an output electrode connected to the input means of the controlled switching means, input means, and a conductive lead connected to said input means.
Claim 18
Dependent Claim
39 words
A circuit according to claim 12 wherein the switching means comprises a second solid state switch connected between the bridge outputs and having a control electrode connected to the valve means and output electrodes connected between the bridge outputs.
Claim 19
Dependent Claim
16 words
A circuit according to claim 16 wherein the valve means is connected between the bridge outputs.
Claim 20
Dependent Claim
24 words
A circuit according to claim 16 wherein the switching means comprises a first solid state switch having primary electrodes connected between the bridge outputs.
Claim 21
Dependent Claim
16 words
A circuit according to claim 16 wherein said switching device comprises a solid state latching switch.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |