US4249111A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic lamp shutdown circuit
Assignee: Pitney Bowes Inc
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Filing: 1979-08-20
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Granted: 1981-02-03
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Expires: 1999-08-20
Abstract
Abstract An automatic lamp shutdown circuit, which comprises a lamp, a line-voltage compensation control circuit for the lamp, and an automatic shutdown circuit operatively connected to the line-voltage compensation control circuit for turning the lamp off after the lamp has been on for a pre-determined amount of time.
Inventors
- 👤 Julius Gluck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:08
CPC Classifications
H; H05; H05B; H05B47/00; H05B47/10; H05B47/16; Y; Y02; Y02B; Y02B20/00; Y02B20/40
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
71 words
In an electrophotocopying machine having a reciprocating carriage for supporting original documents to be copied, a lamp for illuminating said original documents, an automatic lamp shutdown circuit, comprising: a line-voltage compensation control circuit for said lamp, said control circuit including a voltage source; and an automatic shutdown circuit operatively connected to said voltage source for turning the lamp off after the lamp has been on for a pre-determined amount of time.
Claim 2
Dependent Claim
71 words
In an electrophotocopying machine having a reciprocating carriage for supporting original documents to be copied, a lamp for illuminating said original documents, an automatic lamp shutdown circuit, comprising: a line-voltage compensation control circuit for said lamp, said control circuit including a voltage source; and an automatic shutdown circuit operatively connected to said voltage source for turning the lamp off after the lamp has been on for a pre-determined amount of time.
Claim 3
Dependent Claim
26 words
The circuit of claim 1, wherein the automatic shutdown circuit comprises a timer and a switch activated by the timer for shorting out the voltage source.
Claim 4
Dependent Claim
17 words
The circuit of claim 2, wherein the timer comprises a network of resistors and operatively connected capacitors.
Claim 5
Dependent Claim
12 words
The circuit of claim 3, wherein the switch is a Darlington transistor.
Claim 6
Dependent Claim
55 words
The circuit of claim 4, wherein the timer consists of a first resistor operatively connected to the voltage source, a timing capacitor connected in series to said first resistor, and a voltage divider connected in parallel with said capacitor, and wherein the output of said voltage divider drives the base emitter of the Darlington transistor.
Claim 7
Dependent Claim
14 words
The circuit of claim 5, wherein the voltage divider comprises a pair of resistors.
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) | 1984-02-03 | 1984-08-04 | 1985-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-03 | 1988-08-04 | 1989-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-03 | 1992-08-04 | 1993-02-03 | $7700.00 | Window Closed / Lapsed |