Patent US5679894A successfully refreshed from Google Patents.
Patent US3668987A successfully refreshed from Google Patents.
US3668987A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric shutter control circuitry
Assignee: Minolta Co Ltd
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Filing: 1970-08-25
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Granted: 1972-06-13
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Expires: 1990-08-25
Abstract
Abstract First and second switches each having respective first and second switch positions establish shutter control by either a fixed timing circuit or a brightness measuring circuit in accordance with the setting of a distance adjustment ring. The contacts of the switches are mounted on a rotatable change over ring and the distance adjustment ring. The change over ring includes means for setting the flash guide number.
Inventors
- 👤 Toshio Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:46
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
169 words
A shutter control circuit for a photographic camera, comprising: a distance adjusting member; an automatic changeover member mounted adjacent said distance adjusting member; a brightness measuring circuit including a photoconductive element and a condenser connected in series with one another; a resistance connected to said condenser in series for establishing a shutter speed suitable for flash photography; a first switch and a second switch each having first and second contact positions, said first positions of said first and second switches actuating said resistance and condenser to establish a fixed shutter delay; said first switch in said first position and said second switch in said second position actuating said brightness measuring circuit to control the actuation of said shutter in accordance with the brightness of the object; said first switch in said second position controlling the actuation of said shutter in accordance with the brightness of the object; said first switch is actuated manually and said second switch is positioned by said automatic changeover member and said distance adjusting member.
Claim 2
Dependent Claim
169 words
A shutter control circuit for a photographic camera, comprising: a distance adjusting member; an automatic changeover member mounted adjacent said distance adjusting member; a brightness measuring circuit including a photoconductive element and a condenser connected in series with one another; a resistance connected to said condenser in series for establishing a shutter speed suitable for flash photography; a first switch and a second switch each having first and second contact positions, said first positions of said first and second switches actuating said resistance and condenser to establish a fixed shutter delay; said first switch in said first position and said second switch in said second position actuating said brightness measuring circuit to control the actuation of said shutter in accordance with the brightness of the object; said first switch in said second position controlling the actuation of said shutter in accordance with the brightness of the object; said first switch is actuated manually and said second switch is positioned by said automatic changeover member and said distance adjusting member.
Claim 3
Dependent Claim
66 words
A shutter control circuit as set forth in claim 1, wherein said automatic changeover member includes means for setting a flash guide number, and further including a contact connected to said photoconductive element and a contact connected to said resistance; and said distance adjusting member includes a movable coNtact engageable with said contacts of said change over member for establishing said first and second switch positions.
Claim 4
Dependent Claim
46 words
A shutter control circuit as set forth in claim 1, further comprising: a pilot lamp connected to said photoconductive element and actuated with said first switch and said second switches in said second positions and said distance adjustment member set to a distance indicating flash ineffectiveness.
Claim 5
Dependent Claim
70 words
A shutter control circuit as set forth in claim 1, wherein said distance adjusting member is composed of a distance adjusting ring rotatable about the fixed lens barrel of the camera, and said automatic changeover member is rotatable about said fixed lens barrel and composed of a ring having a guide number indicator, and contact members mounted on said changeover ring respectively connected to said photoconductive element and said resistance.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |