US3852791A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Viewfinder mirror buffer device for a single-lens reflex camera
Assignee: Fujifilm Holdings Corp
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Filing: 1973-08-31
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Granted: 1974-12-03
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Expires: 1993-08-31
Abstract
Abstract In a single-lens reflex camera having a viewfinder mirror a buffer device for the mirror comprising a magnet which is moved together with the mirror and an electromagnetic means which is actuated when said mirror is moved to approach the electromagnetic means to produce a force opposing the movement of the mirror, thereby to make it possible to effectively eliminate impact and noise in the high-speed rotation of the mirror.
Inventors
- 👤 S Eukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:10
CPC Classifications
G; G03; G03B; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
149 words
In a single-lens reflex camera having a body, a film plane, a viewfinder and a mirror which is moved relative to the body simultaneously with shutter operation from a first position for introducing light to the viewfinder to a second position for introducing light to the film plane, an improved buffer device for the mirror, comprising: a. a magnet, b. electromagnetic means, c. switch means for energizing said electromagnetic means when said mirror is moved, and d. mechanical linkage means coupling said mirror to one of said magnet and electromagnetic means and arranged to cause relative movement between said magnet and said electromagnetic means in response to movement of said mirror, means mounting the other of said magnet and electromagnet to the camera body, to thereby produce a restraining force opposing such relative movement and hence opposing the relative movement of said mirror when said electromagnetic means is energized.
Claim 2
Dependent Claim
149 words
In a single-lens reflex camera having a body, a film plane, a viewfinder and a mirror which is moved relative to the body simultaneously with shutter operation from a first position for introducing light to the viewfinder to a second position for introducing light to the film plane, an improved buffer device for the mirror, comprising: a. a magnet, b. electromagnetic means, c. switch means for energizing said electromagnetic means when said mirror is moved, and d. mechanical linkage means coupling said mirror to one of said magnet and electromagnetic means and arranged to cause relative movement between said magnet and said electromagnetic means in response to movement of said mirror, means mounting the other of said magnet and electromagnet to the camera body, to thereby produce a restraining force opposing such relative movement and hence opposing the relative movement of said mirror when said electromagnetic means is energized.
Claim 3
Dependent Claim
22 words
A camera mirror buffer device as defined in claim 1, wherein said magnet is stationarily positioned and said electromagnetic means is movable.
Claim 4
Dependent Claim
22 words
A camera mirror buffer device as defined in claim 1, wherein said electromagnetic means is stationarily positioned and said magnet is movable.
Claim 5
Dependent Claim
26 words
A camera mirror buffer device as defined in claim 1, wherein said switch means deenergizes said electromagnetic means when the mirror reaches a position of rest.
Claim 6
Dependent Claim
18 words
A camera mirror buffer device as defined in claim 1, wherein said electromagnetic means is a solenoid coil.
Claim 7
Dependent Claim
50 words
A camera mirror buffer device as defined in claim 1, wherein said electromagnetic means is a printed coil having increasing coil density in the direction of travel of said magnet relative to said printed coil for increasing the magnitude of the restraining force imposed on the movement of said mirror.
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) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |