US3645189A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flashguns
Assignee: Hittech Prontor GmbH
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Filing: 1969-03-11
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Granted: 1972-02-29
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Expires: 1989-03-11
Abstract
Abstract A flashgun using flashbulbs is provided for taking photographs by artificial light. The ignition of the flashbulb is initiated by the flash contact of the camera and an ignition circuit is connected to a primary coil of a transformer. The secondary coil of the transformer is connected to the firing circuit of a thyristor which on conduction energizes an electromagnet of a locking device for holding a shutter in front of the flashbulb in the open position. An electronic switching device including a photosensitive resistor controls a holding magnet cooperating with the drive of the shutter for releasing the shutter at the end of a time interval formed by the electronic switching device in order to allow the shutter to close.
Inventors
- 👤 Waldemar T Rentschler
- 👤 Winfried Espig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:18
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; H05B41/325; G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/04; G03B15/0452
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
119 words
A flashgun using flashbulbs for taking photographs by artificial light including ignition means for the flashbulb initiated by the flash contact of a camera, the ignition circuit for the flashbulb being connected to a primary coil of a transformer, a secondAry coil of said transformer being connected in the firing circuit of a thyristor which on conduction, energizes an electromagnet of locking means for holding a shutter in front of a flashbulb in the open position, and electronic switching means including a photosensitive resistor which controls a holding magnet cooperating with drive means of the shutter to release said shutter at the end of a time interval formed by said electronic switching means to allow said shutter to close.
Claim 2
Dependent Claim
119 words
A flashgun using flashbulbs for taking photographs by artificial light including ignition means for the flashbulb initiated by the flash contact of a camera, the ignition circuit for the flashbulb being connected to a primary coil of a transformer, a secondAry coil of said transformer being connected in the firing circuit of a thyristor which on conduction, energizes an electromagnet of locking means for holding a shutter in front of a flashbulb in the open position, and electronic switching means including a photosensitive resistor which controls a holding magnet cooperating with drive means of the shutter to release said shutter at the end of a time interval formed by said electronic switching means to allow said shutter to close.
Claim 3
Dependent Claim
25 words
The flashgun according to claim 1, wherein said locking means serving to hold said shutter open is engageable with a drive member of said shutter.
Claim 4
Dependent Claim
36 words
The flashgun of claim 1 wherein said locking means serving to hold said shutter in the open position is engageable with a cocking member connected to said shutter for moving said shutter into the cocked position.
Claim 5
Dependent Claim
47 words
The flashgun of claim 3 wherein an armature cooperating with said holding magnet is arranged on an intermediate lever resiliently mounted on said cocking member, said cocking member being a pivotally mounted lever connected to said shutter for moving said shutter into the opened and closed position.
Claim 6
Dependent Claim
17 words
The flashgun of claim 4 wherein said electromagnet cooperating with said locking device is a tractor magnet.
Claim 7
Dependent Claim
144 words
A flashgun using flashbulbs for taking photographs by artificial light including circuit means for igniting the flashbulb by the flash contact of a cooperating camera, said circuit means having an ignition circuit for the flashbulb connected to the primary coil of a transformer, and a secondary coil of said transformer connected in the firing circuit of a thyristor, locking means having an electromagnet energized when said thyristor conducts, said locking means having spring members engageable with a drive member of shutter means for the flashbulb to hold said shutter means in the open position when said electromagnet is energized, electronic timing circuit means including a photosensitive resistor, said electronic timing circuit means controlling a holding magnet cooperating with said drive member of said shutter means to release said shutter means at the end of the time interval formed by said electronic timing circuit means.
Claim 8
Dependent Claim
144 words
A flashgun using flashbulbs for taking photographs by artificial light including circuit means for igniting the flashbulb by the flash contact of a cooperating camera, said circuit means having an ignition circuit for the flashbulb connected to the primary coil of a transformer, and a secondary coil of said transformer connected in the firing circuit of a thyristor, locking means having an electromagnet energized when said thyristor conducts, said locking means having spring members engageable with a drive member of shutter means for the flashbulb to hold said shutter means in the open position when said electromagnet is energized, electronic timing circuit means including a photosensitive resistor, said electronic timing circuit means controlling a holding magnet cooperating with said drive member of said shutter means to release said shutter means at the end of the time interval formed by said electronic timing circuit means.
Claim 9
Dependent Claim
55 words
The flashgun of claim 6 wherein an armature cooperating with said holding magnet is mounted on an intermediate lever, said intermediate lever being resiliently mounted on said drive member, and wherein said drive member is a spring-biased pivotally mounted lever connected to said shutter means for moving said shutter into the open and closed position.
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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |