US3721168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic camera
Assignee: Pentacon GmbH Foto und Feinwerktechnik
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Filing: 1971-08-02
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Granted: 1973-03-20
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Expires: 1991-08-02
Abstract
Abstract The photographic camera is provided with a photoelectric exposure-measuring apparatus which functions in dependance upon the light passing through the objective lens. The measurement may be made with the diaphragm fully open or stopped down to an aperture at which an exposure is to be made. A change-over switch is provided by which either the variable resistor, which is variable together with the diaphragm-setting member in the case of open aperture measurement, or a substitute resistor lying in parallel therewith in the case of working aperture measurement, is connectible into the measurement circuit. For the optional measurement either with open aperture or with working aperture, measuring key means are provided coupled with the change-over switch so that on selection of open aperture measurement the variable resistor is connectible into the measurement circuit and on selection of working aperture measurement the substitute resistor is connectible into the measurement circuit.
Inventors
- 👤 R Noack
- 👤 H Schulze
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:42
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
170 words
In a photographic camera having a housing, a diaphragm aperture in the housing and a diaphragm aperture setting member positioned on the housing, the provision of an exposure measuring circuit including a photo-electric measuring device mounted on the housing in the path of light passing through the diaphragm aperture, a first resistor connected with the photo-electric measuring device and variable by adjustment of the diaphragm setting member, a second resistor connected with the photoelectric measuring device, a change over switch connected in circuit with the first and second resistors and the photoelectric measuring device and measuring key means positioned on the housing and adapted to select open or working aperture exposure measurement whereby with the change over switch in its first position for the purpose of open aperture measurement the first resistor is connected into the measuring circuit whereas with the change over switch in its second position for the purpose of working aperture measurement the second resistor is connected into the measuring circuit in place of the first resistor.
Claim 2
Dependent Claim
170 words
In a photographic camera having a housing, a diaphragm aperture in the housing and a diaphragm aperture setting member positioned on the housing, the provision of an exposure measuring circuit including a photo-electric measuring device mounted on the housing in the path of light passing through the diaphragm aperture, a first resistor connected with the photo-electric measuring device and variable by adjustment of the diaphragm setting member, a second resistor connected with the photoelectric measuring device, a change over switch connected in circuit with the first and second resistors and the photoelectric measuring device and measuring key means positioned on the housing and adapted to select open or working aperture exposure measurement whereby with the change over switch in its first position for the purpose of open aperture measurement the first resistor is connected into the measuring circuit whereas with the change over switch in its second position for the purpose of working aperture measurement the second resistor is connected into the measuring circuit in place of the first resistor.
Claim 3
Dependent Claim
51 words
In a photographic camera according To claim 1 having a preselector diaphragm having diaphragm blades closeable to an aperture presettable by the diaphragm aperture setting member, the provision of spring means adapted to urge the diaphragm blades into the preset position when the measuring key means selects working aperture exposure measurement.
Claim 4
Dependent Claim
147 words
In a photographic camera according to claim 2 the provision of operating switch means connected in the measuring circuit and closeable to enable operation of the measuring circuit, measuring key means having first and second independantly operable keys positioned on the housing for selecting working aperture or open aperture measurement respectively, a first coupling means connected between the change over switch, the operating switch means and the spring means which first coupling means is moveable by the first key to effect change over of the change over switch from its first position to its second position, to effect closure of the operating switch means and movement of the diaphragm aperture to the value set by the diaphragm aperture setting member, a second coupling means connected between the second key and the operating switch means movable by the second key to effect closure of the operating switch means.
Claim 5
Dependent Claim
154 words
In a photographic camera according to claim 2 the provision of operating switch means connected in the measuring circuit and closeable to enable operation of the measuring circuit, measuring key means having first and second independantly operable keys positioned on the housing for selecting working aperture or open aperture measurement respectively, a first coupling means connected between the operating switch means and the spring means which first coupling means is moveable by the first key to effect closure of the operating switch means and movement of the diaphragm aperture to the value set by the diaphragm aperture setting member and a second coupling means connected between the second key, the change over switch and the operating switch means which second coupling means is moveable by the second key to effect closure of the operating switch means and change over of the change over switch from its second normal rest position to its first position.
Claim 6
Dependent Claim
54 words
In a photographic camera according to claim 4 the provision of a return spring coupled to the change over switch urging the switch into its second position and the second coupling means moves the change over switch against the action of the return spring into its first position when the second key is operated.
References Cited (Backward Citations)
US3470805A
Cited
US3545351A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |