US3847475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric shutter control
Assignee: Seiko Koki KK
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Filing: 1974-01-18
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Granted: 1974-11-12
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Expires: 1994-01-18
Abstract
Abstract An electric shutter having an armature operable to an unattracted position for allowing closing of the shutter blades. The armature is biased by a pressure-applying spring toward the attracted position by a greater force than a force applied biasing it away from the attracted position. The pressureapplying spring force is rendered ineffective after the shutter blades have been opened thereby avoiding premature closing of the shutter in the event that the energized electromagnet cannot hold the armature in an attracted position.
Inventors
- 👤 K Kitai
- 👤 Y Nakamura
- 👤 H Ishida
- 👤 S Nagaoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:34
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
176 words
An electric shutter comprising, a plurality of shutter blades operable from a closed position to an open position and back to the closed position, an electromagnet controlling closing of the shutter blades at termination of an exposure time, an armature releasably held mechanically to the electromagnet and attracted by said electromagnet when energized, a holding lever releasably applying a biasing force to the armature biasing it against said electromagnet, means comprising a main driving cam for driving the shutter blades to an open and closed position, an intermediate lever having a pressure-applying spring for applying a pressure to bias the armature toward engaging the electromagnet, an armature lever having an armature-lever spring for biasing the armature away from said electromagnet, the pressure-applying spring having a greater force than the force of the armature-lever spring, said main driving cam having means for engaging the intermediate lever and rendering the pressureapplying spring ineffective to apply force to said armature only after said shutter blades have been opened, and means energizing the electromagnet after said shutter blades are opened.
Claim 2
Dependent Claim
176 words
An electric shutter comprising, a plurality of shutter blades operable from a closed position to an open position and back to the closed position, an electromagnet controlling closing of the shutter blades at termination of an exposure time, an armature releasably held mechanically to the electromagnet and attracted by said electromagnet when energized, a holding lever releasably applying a biasing force to the armature biasing it against said electromagnet, means comprising a main driving cam for driving the shutter blades to an open and closed position, an intermediate lever having a pressure-applying spring for applying a pressure to bias the armature toward engaging the electromagnet, an armature lever having an armature-lever spring for biasing the armature away from said electromagnet, the pressure-applying spring having a greater force than the force of the armature-lever spring, said main driving cam having means for engaging the intermediate lever and rendering the pressureapplying spring ineffective to apply force to said armature only after said shutter blades have been opened, and means energizing the electromagnet after said shutter blades are opened.
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |