US4269496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power supply circuit for camera
Assignee: Nikon Corp
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Filing: 1979-05-30
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Granted: 1981-05-26
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Expires: 1999-05-30
Abstract
Abstract A power supply circuit is so designed that the power supply is interrupted to the load after a predetermined period from a switch closing signal generated when the power switch is closed. The power supply circuit is capable of preventing unnecessary consumption of the battery power resulting from defective insulation of the power switch.
Inventors
- 👤 Ryuzo Motoori
- 👤 Sakuji Watanabe
- 👤 Yoshiaki Ohtsubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:01
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/38; G03B17/40; G03B17/18
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
120 words
In a power supply circuit for use in a photographic camera and provided with a power switch for connecting a load such as an exposure display device to a power source, the improvement comprising: a differentiating circuit for differentiating a switch closing signal generated when said power switch is closed; a timer circuit responsive to the output of said differentiating circuit for initiating a timing operation upon the closing of said power switch, said timing operation terminating after the lapse of a predetermined period which is independent of the length of time said power switch is closed; and means responsive to the output of said timer circuit for connecting said load to the power source only during said timing operation.
Claim 2
Dependent Claim
120 words
In a power supply circuit for use in a photographic camera and provided with a power switch for connecting a load such as an exposure display device to a power source, the improvement comprising: a differentiating circuit for differentiating a switch closing signal generated when said power switch is closed; a timer circuit responsive to the output of said differentiating circuit for initiating a timing operation upon the closing of said power switch, said timing operation terminating after the lapse of a predetermined period which is independent of the length of time said power switch is closed; and means responsive to the output of said timer circuit for connecting said load to the power source only during said timing operation.
Claim 3
Dependent Claim
45 words
A power supply circuit according to claim 1, wherein said timer circuit comprises: a capacitor; means for connecting said capacitor to the power source in response to the output of said differentiating circuit; and means for discharging said capacitor according to a predetermined time constant.
Claim 4
Dependent Claim
52 words
A power supply circuit according to claim 2, further comprising reset means connected to said capacitor and operable in cooperation with the shutter mechanism of said camera to enable charging of said capacitor at shutter charging and operable to disharge said capacitor at the completion of an exposure operable of said camera.
Claim 5
Dependent Claim
31 words
A power supply circuit according to claim 3, wherein said reset means comprises switch means operable in cooperation with said shutter mechanism, said switch means being connected parallel to said capacitor.
Claim 6
Dependent Claim
15 words
A power supply circuit according to claim 1, wherein said power switch is a touch-switch.
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) | 1984-05-25 | 1984-11-24 | 1985-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-25 | 1988-11-24 | 1989-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-25 | 1992-11-24 | 1993-05-26 | $7700.00 | Window Closed / Lapsed |