US3833913A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Closed-loop diaphragm adjustment mechanism for a camera
Assignee: Agfa Gevaert AG
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Filing: 1973-08-29
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Granted: 1974-09-03
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Expires: 1993-08-29
Abstract
Abstract An arrangement is described for automatically adjusting the shutter opening in a camera in accordance with the quantity of light incident on a photosensitive detector of the camera. A pulse generator is triggered when the excitation voltage developed by the detector and applied to the pulse generator input exceeds the latter''s threshold. An electromagnet energized by the triggered pulse generator incrementally advances a springloaded diaphragm via a modified panel and ratchet mechanism in a first direction at the pulse rate, thereby progressively decreasing the shutter opening. A light blocking member in the detector moves in synchronism with the diaphragm to progressively decrease the excitation voltage for the pulse generator as the shutter opening decreases. When such decreasing voltage falls below the pulse generator threshold, the electromagnet is disabled. The diaphragm thereupon retracts at a rate slower than the pulse rate until the corresponding movement of the light blocking member again permits the excitation voltage to exceed the pulse generator threshold, thereby establishing a stable size for the shutter opening.
Inventors
- 👤 R Wick
- 👤 A Winkler
- 👤 E Wagensonner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:43
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/085; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
167 words
In an arrangement for adjusting the shutter opening of a camera in accordance with the quantity of light impinging on a photosensitive detector portion of the camera, wherein a succession of pulses derived from a first voltage proportional to the quantity of the impinging light effects the incremental positioning of a diaphragm over the shutter opening, the improvement which comprises: first means operable in response to the succession of pulses for moving the diaphragm over the shutter opening in a first direction at the pulse rate to vary the size of such opening in a first sense; second means operable during intervals when the first moving means are unoperated for moving the diaphragm over the shutter opening in the opposite direction at a rate slow with respect to the pulse rate to vary the size of such opening in the opposite sense; and means movable in synchronism with the diaphragm for varying the first voltage in accordance with the variations in the size of the shutter opening.
Claim 2
Dependent Claim
167 words
In an arrangement for adjusting the shutter opening of a camera in accordance with the quantity of light impinging on a photosensitive detector portion of the camera, wherein a succession of pulses derived from a first voltage proportional to the quantity of the impinging light effects the incremental positioning of a diaphragm over the shutter opening, the improvement which comprises: first means operable in response to the succession of pulses for moving the diaphragm over the shutter opening in a first direction at the pulse rate to vary the size of such opening in a first sense; second means operable during intervals when the first moving means are unoperated for moving the diaphragm over the shutter opening in the opposite direction at a rate slow with respect to the pulse rate to vary the size of such opening in the opposite sense; and means movable in synchronism with the diaphragm for varying the first voltage in accordance with the variations in the size of the shutter opening.
Claim 3
Dependent Claim
63 words
An arrangement as defined in claim 1, in which the camera has a film-driving motor, and in which the arrangement further comprises, in combination, first externally operable switching means for energizing the photosensitive detector portion, second switching means operable to energize the motor, and delay means for operating the second switching means a predetermined time after the operation of the first switching means.
Claim 4
Dependent Claim
196 words
An arrangement for adjusting the shutter opening of a camera in accordance with the quantity of light impinging on a photosensitive detector portion of the camera, wherein a first voltage proportional to the quantity of the impinging light effects the incremental positioning of a diaphragm over the shutter opening, the improvement which comprises: normally disabled, threshold-controlled means for generating pulses at a first rate when a voltage applied to its input exceeds the threshold; first means for coupling the first voltage to the input of the pulse generating means; first means rendered effective when the pulse generating means are enabled for moving the diaphragm over the shutter opening in a first direction at the first rate to vary the size of such opening in a first sense; second means rendered effective when the pulse generating means are disabled for moving the diaphragm over the shutter opening in the opposite direction at a rate slow with respect to the first rate to vary the size of such opening in the opposite sense; and means movable in synchronism with the diaphragm for varying the first voltage in accordance with the variations in the size of the shutter opening.
Claim 5
Dependent Claim
196 words
An arrangement for adjusting the shutter opening of a camera in accordance with the quantity of light impinging on a photosensitive detector portion of the camera, wherein a first voltage proportional to the quantity of the impinging light effects the incremental positioning of a diaphragm over the shutter opening, the improvement which comprises: normally disabled, threshold-controlled means for generating pulses at a first rate when a voltage applied to its input exceeds the threshold; first means for coupling the first voltage to the input of the pulse generating means; first means rendered effective when the pulse generating means are enabled for moving the diaphragm over the shutter opening in a first direction at the first rate to vary the size of such opening in a first sense; second means rendered effective when the pulse generating means are disabled for moving the diaphragm over the shutter opening in the opposite direction at a rate slow with respect to the first rate to vary the size of such opening in the opposite sense; and means movable in synchronism with the diaphragm for varying the first voltage in accordance with the variations in the size of the shutter opening.
Claim 6
Dependent Claim
70 words
An arrangement as defined in claim 3, in which the first coupling means comprises in combination a differential amplifier having first and second inputs, second means for coupling the first voltage to the first input of said amplifier, third means for coupling a reference voltage to the second input of the amplifier, and fourth means for coupling the output of the amplifier to the input of the pulse generating means.
Claim 7
Dependent Claim
247 words
In an arrangement for adjusting the shutter opening of a camera in accordance with the quantity of light impinging on a photosensitive detector portion of the camera, wherein a normally disabled electromagnet responsive to a first voltage proportional to the quantity of the impinging light effects the incremental positioning of a diaphragm over the shutter opening, the improvement which comprises: a differential amplifier for producing a second voltage proportional to the difference between the first voltage and a reference voltage; threshold-controlled means operable for generating pulses at a first rate when a voltage applied to its input exceeds the threshold; first means for coupling the second voltage to the input of the pulse generating means; second means for coupling the output of the pulse geneRating means to the electromagnet for enabling the electromagnet at the first rate when the pulse generating means are operated; first means rendered effective when the electromagnet is enabled for moving the diaphragm over the shutter opening in a first direction at the first rate to vary the size of such opening in a first sense; second means rendered effective when the electromagnet is disabled for moving the diaphragm over the shutter opening in the opposite direction at a rate slow with respect to the first rate to vary the size of such opening in the opposite sense; and means movable in synchronism with the diaphragm for varying the first voltage in accordance with the variations in the size of the shutter opening.
Claim 8
Dependent Claim
247 words
In an arrangement for adjusting the shutter opening of a camera in accordance with the quantity of light impinging on a photosensitive detector portion of the camera, wherein a normally disabled electromagnet responsive to a first voltage proportional to the quantity of the impinging light effects the incremental positioning of a diaphragm over the shutter opening, the improvement which comprises: a differential amplifier for producing a second voltage proportional to the difference between the first voltage and a reference voltage; threshold-controlled means operable for generating pulses at a first rate when a voltage applied to its input exceeds the threshold; first means for coupling the second voltage to the input of the pulse generating means; second means for coupling the output of the pulse geneRating means to the electromagnet for enabling the electromagnet at the first rate when the pulse generating means are operated; first means rendered effective when the electromagnet is enabled for moving the diaphragm over the shutter opening in a first direction at the first rate to vary the size of such opening in a first sense; second means rendered effective when the electromagnet is disabled for moving the diaphragm over the shutter opening in the opposite direction at a rate slow with respect to the first rate to vary the size of such opening in the opposite sense; and means movable in synchronism with the diaphragm for varying the first voltage in accordance with the variations in the size of the shutter opening.
Claim 9
Dependent Claim
70 words
An arrangement as defined in claim 5, in which the first moving means comprises a magnetic panel attractable when the electromagnet is enabled, a toothed wheel incrementally rotatable by the panel about a first axis when the panel is attracted, and third means for coupling the diaphragm to the toothed wheel for movement of the diaphragm in the first direction in synchronism with the incremental rotation of the toothed wheel.
Claim 10
Dependent Claim
43 words
An arrangement as defined in claim 6, in which the second moving means comprises resilient means for urging the diaphragm in the opposite direction, and unidirectional means associated with the toothed wheel for retarding the movement of the diaphragm in the opposite direction.
Claim 11
Dependent Claim
74 words
An arrangement as defined in claim 6, in which the pulse generating means comprises, in combination, a pair of normally open contacts interconnecting the output of the amplifier and the input of the electromagnet, and a contact arm affixed to the panel, the contact arm being movable between a first position in engagement with the contacts when the electromagnet is disabled and a second position spaced from the contacts when the electromagnet is enabled.
Claim 12
Dependent Claim
27 words
An arrangement as defined in claim 6, in which the third coupling means rigidly associates the diaphragm with the toothed wheel for rotation about the first axis.
Claim 13
Dependent Claim
86 words
An arrangement as defined in claim 6, in which the diaphragm comprises a pair of arms pivotable about a second axis offset from the first axis and having a pair of opposed bosses, and in which the third coupling means comprises camming means affixed to the toothed wheel for rotation about the first axis and engageable with the opposed bosses of the diaphragm arms to pivot the arms away from each other about the second axis when the toothed wheel is rotated in the first direction.
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) | 1977-09-02 | 1978-03-04 | 1978-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-02 | 1982-03-04 | 1982-09-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-02 | 1986-03-04 | 1986-09-03 | $7700.00 | Window Closed / Lapsed |