Patent US3742829A successfully refreshed from Google Patents.
US3742829A
Expired / Lapsed
US
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Mechanical differential for an exposure meter at photographic cameras
Assignee: HASSELBLAD
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Filing: 1972-02-18
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Granted: 1973-07-03
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Expires: 1992-02-18
Abstract
Abstract A camera, of the type provided with interchangeable lenses having preset diaphragms and also provided with exchangeable film magazines, includes an exposure meter which incorporates a differential, e.g., of the cable or articulated type. Correction values for two exposure factors are applied as inputs to the differential through the agency of two axially movable rods which sense adjustable stop members which are, in turn, positioned in accordance with said correction values; and the correction value for a third exposure factor is supplied to the exposure meter independently of the differential. The differential is provided with a release device operative to engage the differential to permit automatic exposure measurement when the two adjustable stop members are available for sensing, and operative to disengage the differential when at least one of the adjustable stop members is not available for sensing, thereby to permit the necessary correction factors to be manually set into a control box forming a portion of the mechanism. A signal device, responsive to the position of the release device, indicates whether automatic or manual exposure measurement is to be effected.
Inventors
- 👤 L Johansson
- 👤 L Tenne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:54
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/24
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
190 words
In a camera adapted to be provided with lenses having preset diaphragms and also to be provided with exchangeable film magazines, and wherein said camera includes an exposure meter of the trough-the-lens type having a mechanical differential provided with two inputs taking the form of axially movable rods adapted to sense the positions of adjustable stop members forming portions of said lenses and magazines respectively, to jointly adjust a variable resistor in accordance with two preselected exposure factors, and wherein the correction value of a third exposure factor is adapted to be supplied to said exposure meter independently of said differential, the improvement wherein said differential includes a release device for selectively engaging and disengaging said differential, said release device including means responsive to the presence of said two adjustable stop members for setting said differential into its engaged condition to permit automatic setting of said exposure meter in accordance with the positions of said adjustable stop members, and means responsive to the absence of at least one of said adjustable stop members for disengaging said differential to permit said correction values to be manually set into said exposure meter.
Claim 2
Dependent Claim
190 words
In a camera adapted to be provided with lenses having preset diaphragms and also to be provided with exchangeable film magazines, and wherein said camera includes an exposure meter of the trough-the-lens type having a mechanical differential provided with two inputs taking the form of axially movable rods adapted to sense the positions of adjustable stop members forming portions of said lenses and magazines respectively, to jointly adjust a variable resistor in accordance with two preselected exposure factors, and wherein the correction value of a third exposure factor is adapted to be supplied to said exposure meter independently of said differential, the improvement wherein said differential includes a release device for selectively engaging and disengaging said differential, said release device including means responsive to the presence of said two adjustable stop members for setting said differential into its engaged condition to permit automatic setting of said exposure meter in accordance with the positions of said adjustable stop members, and means responsive to the absence of at least one of said adjustable stop members for disengaging said differential to permit said correction values to be manually set into said exposure meter.
Claim 3
Dependent Claim
124 words
The structure of claim 1 wherein said axially movable rods project outwardly of the camera box when the exposure meter is not actuated, means for resiliently urgiNg each of said rods to its outwardly projecting position, and coupling means for coupling each rod to said differential with an axial play which corresponds substantially to the extent by which said rods project outwardly of said camera box, whereby said rods can be pressed inwardly toward said camera box to the extent of their axial plays without causing the differential to vary said variable resistor, said release device including means operative to disengage said differential when at least one of said rods is pressed inwardly toward said camera box to the extent of its axial play.
Claim 4
Dependent Claim
30 words
The structure of claim 1 including indicator means responsive to the condition of said release device for indicating whether said differential is in condition for automatic or manual exposure measurement.
Claim 5
Dependent Claim
13 words
The structure of claim 2 wherein said differential is of the cable type.
Claim 6
Dependent Claim
60 words
The structure of claim 4 wherein said coupling means, between each of said rods and said differential, comprises a structural member at said differential having an elongated hole therein, and a sleeve connected to said rod and passing through said elongated hole for axial movement relative to said hole to provide said axial play between said rod and said differential.
Claim 7
Dependent Claim
68 words
The structure of claim 4 including an elongated release arm mounted for pivotal movement adjacent a central position thereof, the free ends of said arm on opposite sides of its pivot being disposed adjacent the innermost ends of said axially movable rods to control the positions of said rods, said release arm being provided with a laterally extending locking arm for controlling the release device of said differential.
Claim 8
Dependent Claim
67 words
The structure of claim 6 including a pivotally mounted spring-loaded balancing arm for the cable of said differential, said balancing arm being located adjacent and coacting with said laterally extending locking arm to lock said balancing arm in position at the time of automatic exposure measurement, and to release said balancing arm for movement with the cable of said differential at the time of manual exposure measurement.
Claim 9
Dependent Claim
23 words
The structure of claim 7 including a cable adjusting device for stretching the cable of said differential at the time of exposure measurement.
Claim 10
Dependent Claim
82 words
The structure of claim 8 including a cable adjusting device disposed adjacent each of said rods, a pair of carrier members disposed adjacent said adjusting devices, said carrier members being provided with holes through which the cable of said differential passes, said holes being arranged to lock said carrier members in position relative to said cable when said cable is taut, and to release said carrier members relative to one another when said cable is slackened temporarily at the time of adjustment.
Claim 11
Dependent Claim
13 words
The structure of claim 1 wherein said differential is of the articulated type.
Claim 12
Dependent Claim
18 words
The structure of claim 10 including means for mounting said rods with axial play relative to said differential.
Claim 13
Dependent Claim
97 words
The structure of claim 10 including a spring-loaded release catch pivotally supported on a journal located between the ends of said catch, means coupling said rods to portions of said catch on opposite sides of said journal, a release arm having a recess therein, and a lateral arm extending from said release catch into locking engagement with said recess when both of said rods project outwardly of the camera box, said lateral arm being disengaged from said recess when at least one of said rods is pressed inwardly toward the camera box to permit manual exposure measurement.
Claim 14
Dependent Claim
42 words
The structure of claim 12 including a rack fastened to one of said rods for operating the release device of said differential, said release arm being pivotally mounted on a journal and having a cog wheel thereon which meshes with said rack.
Claim 15
Dependent Claim
82 words
The structure of claim 13 including a toothed sector attached to said release arm and in mesh engagement with said cog wheel, a link connected between said toothed sector and the other one of said rods, a further rack fastened to said link and operative to assume a position related to the sum of the correction values transferred by both of said rods, and means responsive to the position of said further rack for adjusting the variable resistor of said exposure meter.
Claim 16
Dependent Claim
54 words
The structure of claim 14 wherein said last-named means comprises a further cog wheel in mesh engagement with said further rack, said further cog wheel being mounted on an axle, a rotatable resistance element supported on said axle, and an electrical contact driven by said axle and in slidable engagement with said resistance element.
Claim 17
Dependent Claim
50 words
The structure of claim 12 including a signalling device connected to said release catch for indicating whether said differential is in condition for automatic or manual exposure measurement, said signalling device comprising a movable member bearing symbols which are visible selectively through a window in a wall of said camera.
Claim 18
Dependent Claim
31 words
The structure of claim 3 wherein said indicator means comprises a pivotally mounted member bearing symbols thereon which are selectively visible through a window in an exterior wall of said camera.
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) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |