US3745902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-timer circuit and self timer-device incorporating said self timer circuit
Assignee: Canon Inc
•
Filing: 1972-07-31
•
Granted: 1973-07-17
•
Expires: 1992-07-31
Abstract
Abstract This invention provides a self-timer circuit for a camera including an electronic circuit. The electronic circuit is capable of generating a signal at a predetermined time before the actuation of the timer is completed. To this end, the self-timer device includes a time-constant circuit having resistor and capacitor, a first switching circuit operable between two states in response to a voltage across the capacitor and the output terminal of this switching circuit is coupled to an electromagnet for releasing the shutter, and a display circuit for giving said signal.
Inventors
- 👤 T Taguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:26
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
136 words
A self-timer device for releasing a shutter of a camera comprising a time-constant circuit comprising resistor means having a voltage division point and capacitor, a first switching circuit for switching between two states in response to a voltage across said capacitor, the output terminal of said first switching circuit being coupled to an electromagnet means for releasing the shutter of the camera, and a display circuit means whose input terminal is connected to the voltage division point of said resistor means, said display circuit means comprising a second switching circuit whose input terminal is connected to said voltage division point of said resistor means, and display means connected to the output terminal of said second switching circuit, whereby said display means may give the warning signal before said electromagnet means is energized to release the shutter.
Claim 2
Dependent Claim
136 words
A self-timer device for releasing a shutter of a camera comprising a time-constant circuit comprising resistor means having a voltage division point and capacitor, a first switching circuit for switching between two states in response to a voltage across said capacitor, the output terminal of said first switching circuit being coupled to an electromagnet means for releasing the shutter of the camera, and a display circuit means whose input terminal is connected to the voltage division point of said resistor means, said display circuit means comprising a second switching circuit whose input terminal is connected to said voltage division point of said resistor means, and display means connected to the output terminal of said second switching circuit, whereby said display means may give the warning signal before said electromagnet means is energized to release the shutter.
Claim 3
Dependent Claim
27 words
A self-timer device as set forth in claim 1 wherein said resistor means comprises a variable resistor and a divided voltage is derived from its sliding arm.
Claim 4
Dependent Claim
34 words
A self-timer device as set forth in claim 1 wherein said display circuit further comprises an oscillator whose operation is controlled by the output of said second switching circuit so that display means flashes.
Claim 5
Dependent Claim
66 words
A self-timer device as set forth in claim 1 wherein said switching circuit comprises a differential amplifier one of the input terminals of which is coupled to said capacitor and the other terminal of which is coupled to said resistor means, whereby the self-timer time may be set to a desired time in response to the resistance of said resistor means having a voltage division point.
Claim 6
Dependent Claim
162 words
A camera incorporating a self-timer device foR releasing a shutter of said camera comprising resistor means and a photoelectric cell for measuring the brightness of a subject, switching means for selecting either of said resistor means or said photoelectric cell, a capacitor coupled to said switching means for setting a time, a first switching circuit whose input terminal is connected to said resistor means and whose output terminal is connected to electromagnet means for releasing the shutter of said camera, a second switching circuit means whose input terminal is connected to said photoelectric cell and whose output terminal is connected to control means which controls the closure of said shutter, and a display circuit means whose input terminal is connected to the voltage division point of said resistor means and which comprises a third switching circuit whose input is connected to the voltage division point of said resistor means, and display means connected to the output terminal of said third switching circuit.
Claim 7
Dependent Claim
162 words
A camera incorporating a self-timer device foR releasing a shutter of said camera comprising resistor means and a photoelectric cell for measuring the brightness of a subject, switching means for selecting either of said resistor means or said photoelectric cell, a capacitor coupled to said switching means for setting a time, a first switching circuit whose input terminal is connected to said resistor means and whose output terminal is connected to electromagnet means for releasing the shutter of said camera, a second switching circuit means whose input terminal is connected to said photoelectric cell and whose output terminal is connected to control means which controls the closure of said shutter, and a display circuit means whose input terminal is connected to the voltage division point of said resistor means and which comprises a third switching circuit whose input is connected to the voltage division point of said resistor means, and display means connected to the output terminal of said third switching circuit.
References Cited (Backward Citations)
US3608461A
Cited
US3672267A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |