US3710157A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of monitoring airport runway end identification lamps
Assignee: Crouse Hinds Canada Ltd
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Filing: 1972-02-23
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Granted: 1973-01-09
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Expires: 1992-02-23
Abstract
Abstract A control device for a pair of flashing airport runway end identification lamps which automatically shuts down both lamps when either lamp ceases to flash, and thereby avoids the pilot confusion which could result from a single flashing lamp. This device monitors the surges of line current which flow due to flashing of the lamps and compares a signal, which varies according to the magnitude of the surges, with a threshold, and, if the comparison indicates that both lamps are not flashing, automatically disconnects the power to both lamps.
Inventors
- 👤 D Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:07
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/12; B; B64; B64F; B64F1/00; B64F1/18; B64F1/20; G; G08; G08G; G08G1/00; G08G1/097; H02H7/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
154 words
A control device for simultaneously flashing lamps which constitute part of an airport runway lighting system, said device operable to disconnect said flashing lamps when one of said flashing lamps fail, said control device comprising: a. surge current detection means which monitors surges of current flowing from a power source to said flashing lamps and produces a signal which varies according to the magnitude of said surges of current; b. a means for producing a control value indicative of said flashing lamps operating properly; c. comparator means which receives said surge current signal and compares said surge current signal to said control value and generates a disconnect condition when said surge current signal differs from said control value in a predetermined manner; and d. disconnecting means which is electrically connected between said power source and said flashing lamps and which, when actuated by said disconnect condition, disconnects said flashing lamps from said power source.
Claim 2
Dependent Claim
154 words
A control device for simultaneously flashing lamps which constitute part of an airport runway lighting system, said device operable to disconnect said flashing lamps when one of said flashing lamps fail, said control device comprising: a. surge current detection means which monitors surges of current flowing from a power source to said flashing lamps and produces a signal which varies according to the magnitude of said surges of current; b. a means for producing a control value indicative of said flashing lamps operating properly; c. comparator means which receives said surge current signal and compares said surge current signal to said control value and generates a disconnect condition when said surge current signal differs from said control value in a predetermined manner; and d. disconnecting means which is electrically connected between said power source and said flashing lamps and which, when actuated by said disconnect condition, disconnects said flashing lamps from said power source.
Claim 3
Dependent Claim
60 words
The control device as specified in claim 1, wherein said control device is designed to be energized from said power source and said surge current detection means has a low impedance and is effectively in series with said lamps, whereby said control device can be conveniently added to existing installations, and wherein said control device is designed to be failsafe.
Claim 4
Dependent Claim
45 words
The control device as specified in claim 2, including a starting means which, when power first becomes available, causes said disconnecting means to connect said lamps to said power source, and for a predetermined time thereafter prevents said disconnect condition from actuating said disconnecting means.
Claim 5
Dependent Claim
78 words
The control device as specified in claim 3, wherein: a. a set of electrical contacts which operate simultaneously with said disconnecting means is provided to facilitate remote indication of the status of said flashing lamps; b. said flashing lamps are two capacitor discharge lamps; and c. said surge current detector comprises a current transformer and said surge current signal is produced as a result of energy from said current transformer passing through a diode into a resistor-capacitor network.
Claim 6
Dependent Claim
121 words
The control device as specified in claim 3, wherein failsafe operation is provided by: a. said disconnect condition being generated from the absence of an AC signal coupled through a capacitor to the gate of an SCR; b. a flow of power from an AC supply to the actuating coil of said disconnecting means being controlled by said SCR; and c. a fuse being provided in series with said actuating coil of said disconnecting means and a diode being provided in parallel with said actuating coil of said disconnecting means, which diode is connected anode to anode with said SCR, said fuse being sized to blow if said SCR shorts and subjects said fuse to half-wave current without any series load.
References Cited (Backward Citations)
US3503062A
Cited
US3648105A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |