US3573541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistor-controlled emergency exit unit
Assignee: Individual
•
Filing: 1969-04-21
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Granted: 1971-04-06
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Expires: 1989-04-21
Abstract
Abstract A changeover device for an emergency exit unit having lamps with AC filaments normally operated by a main power supply and normally unenergized DC filaments for operation by a standby battery, which is normally kept charged by a charger circuit. A transistor circuit, when conductive, sends power from the battery to the DC filaments, but the circuit provides for reverse-biasing the base of the transistor while the main power supply is on. An electric charge is created and stored while the main power supply is on, and upon discharge sends bias voltage to the transistor to make it conductive. Self-holding means is energized by the same discharge through said transistor, for retaining the connection between the battery and the DC filaments, and the self-holding means is released when the voltage of the battery drops a predetermined amount below normal, thereby disconnecting the battery from said DC filaments and preventing further battery discharge.
Inventors
- 👤 Robert O Dunn
- 👤 David C Wilton
- 👤 Joseph R Dydynski
- 👤 Jerry D Haney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:47
CPC Classifications
G; G08; G08B; G08B7/00; G08B7/06; G08B7/062; H; H02; H02J; H02J7/00; H02J7/90; H02J7/96; H02J9/00; H02J9/02
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
157 words
A changeover device for an emergency exit unit having lamps with AC filaments normally operated by a main power supply and normally unenergized DC filaments, and having a standby battery, including in combination: transistor means, which, when conductive, sends power from said battery to said DC filaments; bias means for reverse-biasing the base of said transistor means while said main power supply is on, to render it nonconducting; charge means for creating and storing an electric charge while said main power supply is on, said charge means upon discharge sending bias voltage to said transistor means to make it conductive; self-holding means energized by discharge of said charge means through said transistor means for retaining said connection between the battery and said DC filaments; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said DC filaments and preventing further battery discharge.
Claim 2
Dependent Claim
157 words
A changeover device for an emergency exit unit having lamps with AC filaments normally operated by a main power supply and normally unenergized DC filaments, and having a standby battery, including in combination: transistor means, which, when conductive, sends power from said battery to said DC filaments; bias means for reverse-biasing the base of said transistor means while said main power supply is on, to render it nonconducting; charge means for creating and storing an electric charge while said main power supply is on, said charge means upon discharge sending bias voltage to said transistor means to make it conductive; self-holding means energized by discharge of said charge means through said transistor means for retaining said connection between the battery and said DC filaments; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said DC filaments and preventing further battery discharge.
Claim 3
Dependent Claim
30 words
The device of claim 1 having battery-charging means connected to said battery and to said main power supply for keeping said battery charged while said main power supply is operative.
Claim 4
Dependent Claim
39 words
The device of claim 2 wherein said battery-charging means includes a silicon-controlled rectifier SCR in series with and between said battery and said main power supply and having a gate bias provided across a zener diode and resistance means.
Claim 5
Dependent Claim
23 words
The device of claim 3 wherein a diode protects the SCR gate from reverse voltages in excess of the SCR gate-cathode threshold voltage.
Claim 6
Dependent Claim
69 words
The device of claim 1 wherein said transistor means comprises a main transistor and said self-holding means comprises a pair of transistors comprising a complementary regenerative circuit with latcHing action for said main transistor to provide base current to said main transistor sufficient to saturate said main transistor when said main power supply is off and thereby to provide a low-resistance path from said battery to said DC filaments.
Claim 7
Dependent Claim
43 words
The device of claim 1 having release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below the normal voltage of said battery, thereby disconnecting said battery from said DC filaments and preventing further battery discharge.
Claim 8
Dependent Claim
186 words
A changeover device for an emergency exit unit having lamps with AC filaments normally operated by a main power supply and normally unenergized DC filaments, and having a standby battery, including in combination: a battery charger for said battery for retaining the strength of said battery when the main power supply is on, and a complementary bistable circuit comprising; a transistor for sending power from said battery to said DC filaments when its base is forwardly biased; reverse-bias means connected to the base of said transistor while said main power supply is on to render said transistor nonconductive; capacitor means for creating and storing an electric charge while said main power supply is on, said capacitor means upon discharge sending forward bias voltage to said transistor to make it conductive; self-holding means energized by discharge of said capacitor means through said transistor for retaining the connection between the battery and said DC filaments; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said DC filaments and preventing further battery discharge.
Claim 9
Dependent Claim
186 words
A changeover device for an emergency exit unit having lamps with AC filaments normally operated by a main power supply and normally unenergized DC filaments, and having a standby battery, including in combination: a battery charger for said battery for retaining the strength of said battery when the main power supply is on, and a complementary bistable circuit comprising; a transistor for sending power from said battery to said DC filaments when its base is forwardly biased; reverse-bias means connected to the base of said transistor while said main power supply is on to render said transistor nonconductive; capacitor means for creating and storing an electric charge while said main power supply is on, said capacitor means upon discharge sending forward bias voltage to said transistor to make it conductive; self-holding means energized by discharge of said capacitor means through said transistor for retaining the connection between the battery and said DC filaments; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said DC filaments and preventing further battery discharge.
Claim 10
Dependent Claim
44 words
The device of claim 7 wherein said self-holding means comprises a pair of additional transistors comprising a complementary regenerative circuit to provide base current to the aforesaid transistor sufficient to saturate it and thereby latch it on when said main power supply is off.
Claim 11
Dependent Claim
144 words
An automatic changeover device for a unit normally operated by a main AC power supply and having a standby battery, including in combination: transistor means, which, when conductive, sends power from said battery to said unit; bias means for reverse-biasing the base of said transistor means while said main power supply is on, to render it nonconducting; charge means for creating and storing an electric charge while said main power supply is on, said charge means upon discharge sending bias voltage to said transistor means to make it conductive; self-holding means energized by discharge of said charge means through said transistor means for retaining said connection between the battery and said unit; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said unit and preventing further battery discharge.
Claim 12
Dependent Claim
144 words
An automatic changeover device for a unit normally operated by a main AC power supply and having a standby battery, including in combination: transistor means, which, when conductive, sends power from said battery to said unit; bias means for reverse-biasing the base of said transistor means while said main power supply is on, to render it nonconducting; charge means for creating and storing an electric charge while said main power supply is on, said charge means upon discharge sending bias voltage to said transistor means to make it conductive; self-holding means energized by discharge of said charge means through said transistor means for retaining said connection between the battery and said unit; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said unit and preventing further battery discharge.
Claim 13
Dependent Claim
29 words
The device of claim 9 having battery-charging means connected to said battery and to said main power supply for keeping said battery charged while main power supply is operative.
Claim 14
Dependent Claim
39 words
The device of claim 10 wherein said battery-charging means includes a silicon-controlled rectifier SCR in series with and between said battery and said main power supply and having a gate bias provided across a zener diode and resistance means.
Claim 15
Dependent Claim
23 words
The device of claim 11 wherein a diode protects the SCR gate from reverse voltages in excess of the SCR gate-cathode threshold voltage.
Claim 16
Dependent Claim
68 words
The device of claim 9 wherein said transistor means comprises a main transistor and said self-holding means comprises a pair of transistors comprising a complementary regenerative circuit with latching action for said main transistor to provide base current to said main transistor sufficient to saturate said main transistor when said main power supply is off and thereby to provide a low-resistAnce path from said battery to said unit.
Claim 17
Dependent Claim
42 words
The device of claim 9 having release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below the normal voltage of said battery, thereby disconnecting said battery from said unit and preventing further battery discharge.
Claim 18
Dependent Claim
171 words
A changeover device for a unit normally operated by a main AC power supply having a standby battery, including in combination: a battery charger for said battery for retaining the strength of said battery when the main power supply is on, and a complementary bistable circuit comprising; a transistor for sending power from said battery to said unit when its base is forwardly biased; reverse-bias means connected to the base of said transistor while said main power supply is on to render said transistor nonconductive; capacitor means for creating and storing an electric charge while said main power supply is on, said capacitor means upon discharge sending forward bias voltage to said transistor to make it conductive; self-holding means energized by discharge of said capacitor means through said transistor for retaining the connection between the battery and said unit; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said unit, and preventing further battery discharge.
Claim 19
Dependent Claim
171 words
A changeover device for a unit normally operated by a main AC power supply having a standby battery, including in combination: a battery charger for said battery for retaining the strength of said battery when the main power supply is on, and a complementary bistable circuit comprising; a transistor for sending power from said battery to said unit when its base is forwardly biased; reverse-bias means connected to the base of said transistor while said main power supply is on to render said transistor nonconductive; capacitor means for creating and storing an electric charge while said main power supply is on, said capacitor means upon discharge sending forward bias voltage to said transistor to make it conductive; self-holding means energized by discharge of said capacitor means through said transistor for retaining the connection between the battery and said unit; and release means for releasing said self-holding means when the voltage of said battery drops a predetermined amount below normal, thereby disconnecting said battery from said unit, and preventing further battery discharge.
Claim 20
Dependent Claim
44 words
The device of claim 15 wherein said self-holding means comprises a pair of additional transistors comprising a complementary regenerative circuit to provide base current to the aforesaid transistor sufficient to saturate it and thereby latch it on when said main power supply is off.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |