US5086293A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Line interruption supervisory device for a fire alarm system
Assignee: Nohmi Bosai Ltd
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Filing: 1990-06-22
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Granted: 1992-02-04
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Expires: 2010-06-22
Abstract
Abstract A line interruption supervisory device for a fire alarm system is capable of reliably carrying out the line supervision even if the line length is long and/or there is a large number of connected fire detectors. To this end, a terminating capacitor is connected across the terminal of a pair of power/signal lines to which fire detectors are connected. A memory first stores the voltage available on the power/signal lines when the line supervision is requested, immediately followed by the interruption by a cut-off circuit of the power supply to a pair of power/signal lines, and further followed by a comparison of the voltage available on the power/signal lines before the power supply interruption with a line voltage available after a lapse of a predetermined time from the power supply interruption by a line interruption discriminating circuit to determine, according to any difference between these voltages, whether there is an open power/signal line.
Inventors
- 👤 Kaoru Takahashi
- 👤 Akio Tsumuji
- 👤 Ryuji Shutoku
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:34
CPC Classifications
G; G08; G08B; G08B29/00; G08B29/02; G08B29/06
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
134 words
A line interruption supervisory device for a fire alarm system, comprising: a terminating capacitor connected across a terminal of a pair of power/signal lines to which fire detectors are connected; a cut-off means for cutting off a power supply to the power/signal lines; a discharge means for causing the terminating capacitor to discharge upon interruption of the power supply to the power/signal lines; a memory means for storing a first voltage available on the power/signal lines immediately before interruption of the power supply; and a line interruption discriminating means for determining, according to any difference between a second voltage available on the power/signal lines after a lapse of a predetermined time from the interruption of the power supply and the first voltage stored in said memory means, whether there is an open power/signal line.
Claim 2
Dependent Claim
134 words
A line interruption supervisory device for a fire alarm system, comprising: a terminating capacitor connected across a terminal of a pair of power/signal lines to which fire detectors are connected; a cut-off means for cutting off a power supply to the power/signal lines; a discharge means for causing the terminating capacitor to discharge upon interruption of the power supply to the power/signal lines; a memory means for storing a first voltage available on the power/signal lines immediately before interruption of the power supply; and a line interruption discriminating means for determining, according to any difference between a second voltage available on the power/signal lines after a lapse of a predetermined time from the interruption of the power supply and the first voltage stored in said memory means, whether there is an open power/signal line.
Claim 3
Dependent Claim
35 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1) wherein the cut-off means, discharge means, memory means and line interruption discriminating means are provided in a control panel.
Claim 4
Dependent Claim
34 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1) wherein the cut-off means, discharge means, memory means and line interruption discriminating means are provided in a repeater.
Claim 5
Dependent Claim
30 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1), (2), or (3) wherein the terminating capacitor is charged through a constant current circuit.
Claim 6
Dependent Claim
34 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1), (2), or (3) wherein the discharge means causes the terminating capacitor to discharge through a constant current circuit.
Claim 7
Dependent Claim
45 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1), (2), or (3) wherein the terminating capacitor is charged through a constant current circuit, and the discharge means causes the terminal capacitor to discharge through the constant current circuit.
Claim 8
Dependent Claim
45 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1), (2), or (3) wherein the line interruption discriminating means determine that there is an open power/signal line when the line interrupted state has been detected a plurality of times.
Claim 9
Dependent Claim
59 words
A line interruption supervisory device for a fire alarm system as set forth in claim (1), (2), or (3) wherein the line interruption discriminating means is equipped with a restoration discriminating means to determine whether the line interruption state has been restored to a normal state, and initiates a line interruption restoration signal upon restoration from the line interruption.
Claim 10
Dependent Claim
56 words
A line interruption supervisory device for a fire alarm system as set forth in claim (7) wherein the line interruption discriminating means is equipped with a restoration discriminating means to determine whether the line interruption state has been restored to a normal state, and initiates a line interruption restoration signal upon restoration from the line interruption.
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) | 1995-02-03 | 1995-08-05 | 1996-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-03 | 1999-08-05 | 2000-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-03 | 2003-08-05 | 2004-02-04 | $7700.00 | Window Closed / Lapsed |