US3662383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Security alarm system
Assignee: Systron Donner Corp
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Filing: 1970-08-07
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Granted: 1972-05-09
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Expires: 1990-08-07
Abstract
Abstract Security alarm system of the McCulloh loop type in which the polarity of the voltage applied to one end of the loop is automatically reversed when abnormal conditions exist in the loop, thus maintaining the loop in an operable condition despite the occurrence of openings and/or shorts to ground in the loop. The voltage is automatically restored to its normal polarity upon correction of the opening and/or grounding.
Inventors
- 👤 Mohan Ajmani
- 👤 Larry K De Lowe
- 👤 Thomas C Hankins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:50
CPC Classifications
G; G08; G08B; G08B25/00; G08B25/01; G08B25/04; G08B25/045
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
156 words
In a security alarm system, an electrically conductive loop having first and second ends, at least one transmitter connected intermediate said ends for transmitting alarm signals through said loop by alternately opening and grounding the same, first recording means operably connected to the first end of said loop for recording alarm signals received at said first end, second recording means operably connected to the second end of said loop for recording alarm signals received at said second end, a direct current power source having a first terminal connected to said first end and a second terminal connected to ground, said terminals being of opposite electrical polarities, and automatic conditioning means at the second end of said loop for monitoring the condition of said loop and connecting said second end to said second terminal when said condition is normal and connecting said second end to said first terminal in response to opening and/or grounding of said loop
Claim 2
Dependent Claim
156 words
In a security alarm system, an electrically conductive loop having first and second ends, at least one transmitter connected intermediate said ends for transmitting alarm signals through said loop by alternately opening and grounding the same, first recording means operably connected to the first end of said loop for recording alarm signals received at said first end, second recording means operably connected to the second end of said loop for recording alarm signals received at said second end, a direct current power source having a first terminal connected to said first end and a second terminal connected to ground, said terminals being of opposite electrical polarities, and automatic conditioning means at the second end of said loop for monitoring the condition of said loop and connecting said second end to said second terminal when said condition is normal and connecting said second end to said first terminal in response to opening and/or grounding of said loop
Claim 3
Dependent Claim
20 words
A security alarm system as in claim 1 wherein said automatic conditioning means includes at least one electronic switching element.
Claim 4
Dependent Claim
29 words
A security alarm system as in claim 1 together with indicator means connected to said automatic conditioning means for giving a visual indication of the condition of said loop.
Claim 5
Dependent Claim
34 words
A security alarm system as in claim 1 wherein said automatic conditioning means includes means for reconnecting said second end to said second terminal upon correction of an opening and/or grounding of said loop.
Claim 6
Dependent Claim
30 words
A security alarm system as in claim 1 wherein said power source includes means for maintaining the magnitude of the current flowing in said loop at a predetermined constant level.
Claim 7
Dependent Claim
143 words
In a monitoring station for use with a protective loop comprising an electrically conductive line and at least one transmitter located remotely of said monitoring station for transmitting pulse coded alarm signals over said line by alternately grounding and opening the same, a direct current power source having a first terminal connected to the first end of said line and a second terminal connected to ground, said first and second terminals being of opposite electrical polarities, and automatic line conditioning means connected to the second end of said line for monitoring the condition of said line and connecting said second end to the second terminal of said power source in the absence of an opening and/or grounding of said line and for connecting said second end to the first terminal of said source in response to an opening and/or grounding of said line.
Claim 8
Dependent Claim
143 words
In a monitoring station for use with a protective loop comprising an electrically conductive line and at least one transmitter located remotely of said monitoring station for transmitting pulse coded alarm signals over said line by alternately grounding and opening the same, a direct current power source having a first terminal connected to the first end of said line and a second terminal connected to ground, said first and second terminals being of opposite electrical polarities, and automatic line conditioning means connected to the second end of said line for monitoring the condition of said line and connecting said second end to the second terminal of said power source in the absence of an opening and/or grounding of said line and for connecting said second end to the first terminal of said source in response to an opening and/or grounding of said line.
Claim 9
Dependent Claim
49 words
A monitoring station as in claim 6 further including a recording tape driveN by a motor adapted to be actuated in response to said pulse coded alarm signal and recording means connected to each end of said line for recording alarm signals received at each end on said tape.
Claim 10
Dependent Claim
41 words
A monitoring station as in claim 7 further including timing capacitor means connected to said motor for maintaining said motor in its actuated condition for a predetermined period of time after the receipt of the first pulse in said alarm signal.
Claim 11
Dependent Claim
139 words
A monitoring station as in claim 6 wherein said automatic line conditioning means includes an electronic switching device and a relay switch, said electronic switching device having first and second terminals and a control element connected to the second end of said line for controlling the conductivity between said terminals in accordance with the condition of said line, said terminals being connected for controlling the flow of current from said source to the operating coil of said relay switch, said relay switch having a pair of terminals each connected to one of the terminals of said power source and a contact member connected to the second end of said line movable between said pair of terminals for connecting said second end to one of said pair of terminals in accordance with the state of energization of said operating coil.
Claim 12
Dependent Claim
15 words
A monitoring station as in claim 9 wherein said electronic switching element is a transistor.
Claim 13
Dependent Claim
42 words
A monitoring station as in claim 6 together with constant current regulating means at both ends of said loop for maintaining the current supplied to all portions of the line at a predetermined constant level regardless of the condition of the line.
Claim 14
Dependent Claim
43 words
A security alarm system as in claim 1 further including a recording chart and motive means for moving said chart in a first direction, said first and second recording means each including a recording pin for recording the alarm signals on said chart.
Claim 15
Dependent Claim
34 words
A security alarm system as in claim 12 further including means for engaging said motive means for a predetermined period of time upon receipt of an alarm signal at either end of said loops.
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) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |