Patent US3822393A successfully refreshed from Google Patents.
US3822393A
Expired / Lapsed
US
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Electronic strobe
Assignee: Berkey Photo Inc
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Filing: 1972-10-11
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Granted: 1974-07-02
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Expires: 1992-10-11
Abstract
Abstract An electronic strobe circuit for flash cameras or flash attachments in which a capacitive energy storage circuit is discharged into a flash tube to provide illumination in synchronism with the opening of the camera shutter. The strobe includes a charging circuit for gradually charging the storage circuit toward a predetermined charge level sufficient for illuminating the flash tube to a desired intensity upon opening of the shutter and a charge limiting circuit including a balanceable bridge coupled to the storage circuit and a detecting device for inhibiting operation of the charging circuit whenever the voltage across the flash tube reaches a desired level. The charge limiting circuit causes the storage circuit to be operated in an intermittent or pulsating manner when it reaches the desired flash voltage, the pulsating nature of the limiting circuit being additionally utilized to provide an audio-visual indication to the operator when the storage circuit is fully charged.
Inventors
- 👤 Z Karpol
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:45
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/05; G03B2215/00; G03B2215/05; G03B2215/0503
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
In an electronic camera flash unit having a capacitive energy storage circuit which is discharged into a flash tube in synchronism with the opening of the camera shutter, the combination comprising: a direct current source; a charging circuit coupled to said source for gradually charging said storage circuit toward a predetermined charge level sufficient for illuminating said flash tube to a desired intensity upon opening of said shutter; charging limiting means including: a) a balanceable bridge circuit having opposite corners thereof coupled across said storage circuit and adapted to be unbalanced to produce an output signal whenever the charge in said storage circuit rises past said predetermined level and b) means operatively associated with said bridge circuit for alternately deactivating and reactivating said charging circuit in response to the presence or absence, reSpectively, of said output signal; and charge monitoring means operatively associated with said charging circuit for providing an audible tone whenever said charging circuit is active.
Claim 2
Dependent Claim
158 words
In an electronic camera flash unit having a capacitive energy storage circuit which is discharged into a flash tube in synchronism with the opening of the camera shutter, the combination comprising: a direct current source; a charging circuit coupled to said source for gradually charging said storage circuit toward a predetermined charge level sufficient for illuminating said flash tube to a desired intensity upon opening of said shutter; charging limiting means including: a) a balanceable bridge circuit having opposite corners thereof coupled across said storage circuit and adapted to be unbalanced to produce an output signal whenever the charge in said storage circuit rises past said predetermined level and b) means operatively associated with said bridge circuit for alternately deactivating and reactivating said charging circuit in response to the presence or absence, reSpectively, of said output signal; and charge monitoring means operatively associated with said charging circuit for providing an audible tone whenever said charging circuit is active.
Claim 3
Dependent Claim
68 words
In an electronic camera flash unit the combination according to claim 1 further including means for leaking charge from said storage circuit during deactivation of said charging means so as to effect alternating deactivation and reactivation of said charging circuit after the charge level of said storage circuit reaches said predetermined charge level, whereby said audible tone pulsates in synchronism with the charge-discharge cycle of said storage circuit.
Claim 4
Dependent Claim
41 words
In an electronic camera flash unit, the combination according to claim 2 wherein said charge monitoring means includes an auxiliary light means coupled to said charging circuit and operative to provide a repetitive visual signal in synchronism with said audible tone.
Claim 5
Dependent Claim
36 words
In an electronic camera flash unit, the combination according to claim 3 wherein the repetition rate of pulsating tone and light is approximately 1/2 - 5 Hz after said storage circuit achieves said predetermined charge level.
Claim 6
Dependent Claim
94 words
In an electronic camera flash unit, the combination according to claim 1 wherein said charging includes a D.C. to A.C. converter consisting of a) an oscillator selectively coupled to said direct current source for providing an A.C. signal, b) step-up transformer means associated with said oscillator for providing a high voltage A.C. signal of a peak amplitude at least an order of magnitude greater than the voltage of said direct current source, and c) means for coupling said high voltage A.C. signal to said storage circuit so as to increase the charge level thereof.
Claim 7
Dependent Claim
31 words
In an electronic camera flash unit, the combination according to claim 21 wherein said step-up transformer means is a magnetostrictive transducer providing an audible tone during operation of said charging circuit.
Claim 8
Dependent Claim
161 words
In an electronic camera flash unit having a capacitive energy storage circuit which is discharged into a flash tube in synchronism with the opening of the camera shutter, the combination comprising: a direct current source; a charging circuit coupled to said source for gradually charging said storage circuit toward a predetermined charge level sufficient for illuminating said flash tube to a desired intensity upon opening of said shutter; and charge limiting means including: a) a zener regulated balanceable bridge circuit having opposite corners thereof coupled across said storage circuit and adapted to be unbalanced to produce an output which goes to a first polarity from a second polarity as the charge in said storage circuit rises past said predetermined level, b) means responsive to said unbalance of a first polarity for deactivating said charging circuit, and c) means associated with said deactivating means for reactivating said charging circuit when the charge level of said storage circuit falls below said predetermined level.
Claim 9
Dependent Claim
161 words
In an electronic camera flash unit having a capacitive energy storage circuit which is discharged into a flash tube in synchronism with the opening of the camera shutter, the combination comprising: a direct current source; a charging circuit coupled to said source for gradually charging said storage circuit toward a predetermined charge level sufficient for illuminating said flash tube to a desired intensity upon opening of said shutter; and charge limiting means including: a) a zener regulated balanceable bridge circuit having opposite corners thereof coupled across said storage circuit and adapted to be unbalanced to produce an output which goes to a first polarity from a second polarity as the charge in said storage circuit rises past said predetermined level, b) means responsive to said unbalance of a first polarity for deactivating said charging circuit, and c) means associated with said deactivating means for reactivating said charging circuit when the charge level of said storage circuit falls below said predetermined level.
References Cited (Backward Citations)
US2977524A
Cited
US3162786A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-01 | 1977-12-31 | 1978-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-01 | 1981-12-31 | 1982-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-01 | 1985-12-31 | 1986-07-02 | $7700.00 | Window Closed / Lapsed |