US3906292A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for controlling lighting time of lamp
Assignee: Ricoh Co Ltd
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Filing: 1973-11-02
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Granted: 1975-09-16
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Expires: 1993-11-02
Abstract
Abstract A series circuit consiting of a device for obtaining a constant voltage and a resistor, a series circuit consisting of a resistor and a charging-discharging circuit adapted to be charged to a predetermined level when a trigger switch is closed and then gradually discharged, and a circuit consisting of a lamp, a switching circuit and its output circuit, are connected in parallel to each other and to a DC power source. The control voltage and the reference voltage of the switching circuit are derived from the junction between the charging-discharging circuit and the resistor connected in series thereto and the junction between the device for obtaining a constant voltage and the resistor connected in series thereto, respectively. When the voltage of the DC power source drops below the rated voltage, the voltage difference between said two junctions is increased so that the ''''on'''' time of the switching circuit is increased, thereby increasing the lighting time of the lamp.
Inventors
- 👤 Akira Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:16
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/02; H02M3/04; H02M3/10; H02M3/145; H02M3/155; H02M3/156; H02M3/1563
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
270 words
A Device for controlling a lighting time interval of a lamp, comprising; a. a DC power source having a nonconstant voltage output; b. a charging-discharging circuit and a trigger switch connected in series, the series combination being connected in parallel with said DC power source and charged to a constant predetermined voltage when the trigger switch is closed, and then discharged when the trigger switch is opened; c. a switching circuit having two states connected to said charging-discharging circuit; d. a lamp connected to said switching circuit so as to be turned on and off in response to the state of said switching circuit; e. a series circuit comprising a resistor and means for obtaining a constant voltage, said series circuit being connected in parallel with said DC power source to obtain a voltage at the junction of the resistor and the constant voltage means which is the voltage of the DC power source less the constant voltage drop of said constant voltage means; and f. a switching element having a control terminal and a reference terminal in said switching circuit, said control terminal being connected to said charging-discharging circuit and said reference terminal being connected to the junction between said means for obtaining a constant voltage and said resistor, the difference between the voltage at the control terminal and the voltage at the reference terminal being an inverse function of said DC power source voltage output and the voltage difference controlling the state of said switching circuit such that said switching circuit turns on said lamp for a longer time interval as said DC power source voltage output decreases.
Claim 2
Independent Claim
270 words
A Device for controlling a lighting time interval of a lamp, comprising; a. a DC power source having a nonconstant voltage output; b. a charging-discharging circuit and a trigger switch connected in series, the series combination being connected in parallel with said DC power source and charged to a constant predetermined voltage when the trigger switch is closed, and then discharged when the trigger switch is opened; c. a switching circuit having two states connected to said charging-discharging circuit; d. a lamp connected to said switching circuit so as to be turned on and off in response to the state of said switching circuit; e. a series circuit comprising a resistor and means for obtaining a constant voltage, said series circuit being connected in parallel with said DC power source to obtain a voltage at the junction of the resistor and the constant voltage means which is the voltage of the DC power source less the constant voltage drop of said constant voltage means; and f. a switching element having a control terminal and a reference terminal in said switching circuit, said control terminal being connected to said charging-discharging circuit and said reference terminal being connected to the junction between said means for obtaining a constant voltage and said resistor, the difference between the voltage at the control terminal and the voltage at the reference terminal being an inverse function of said DC power source voltage output and the voltage difference controlling the state of said switching circuit such that said switching circuit turns on said lamp for a longer time interval as said DC power source voltage output decreases.
Claim 3
Dependent Claim
45 words
A device as defined in claim 1 wherein said charging-discharging circuit comprises: a capacitor; a variable resistor; and a second means for obtaining a constant voltage, said capacitor, said resistor and said means for obtaining a constant voltage being connected in parallel with each other.
Claim 4
Dependent Claim
40 words
A device as defined in claim 1 wherein said trigger switch comprises a switch and circuit means for providing a differentiated output pulse, the duration of said pulse being substantially independent of the duration of activation of said trigger switch.
Claim 5
Dependent Claim
30 words
A device as defined in claim 3 wherein said circuit means comprises: a transistor; and a differentiating circuit activated by said switch and connected to the base of said transistor.
Claim 6
Dependent Claim
18 words
A device as in claim 2 wherein said means for obtaining a constant voltage is a zener diode.
References Cited (Backward Citations)
US2923863A
Cited
US3192449A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |