US4039898A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic flash apparatus
Assignee: West Electric Co Ltd
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Filing: 1974-09-23
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Granted: 1977-08-02
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Expires: 1994-09-23
Abstract
Abstract An electronic photographic flash apparatus which is useful as an artificial light source for taking photographs. The apparatus of this invention does not use an AC charger or the like as its power source, but it uses a plurality of secondary batteries normally held in a charged state by a primary battery, whereby when the flash apparatus is to be used, the connection of the plurality of the secondary batteries is changed to quickly charge a main discharge capacitor of the flash apparatus. By virtue of the ability of the apparatus to quickly charge its main discharge capacitor, the electronic flash apparatus in accordance with the present invention can effectively associate its operation with the operation of the shutter release of a photographic camera when it is incorporated in the latter.
Inventors
- 👤 Hiroshi Iwata
- 👤 Satoru Misaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:12
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/30; H05B41/32; H05B41/325
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
206 words
A photographic flash apparatus comprising: a power supply means including a plurality of rechargeable secondary cells for supplying a large discharging current to a load, a primary cell, connectable to said plurality of secondary cells, havig a small self-discharging factor and a terminal voltage higher than a final charge voltage of said secondary cells, and a first switching means for connecting said primary cell to said plurality of secondary cells; a DC-DC converter circuit including an oscillating transistor having base, emitter and collector terminals, an oscillation transformer connected to said oscillating transistor and a second switching means connected to said oscillating transistor; said power supply means being connected to an input of said DC-DC converter circuit; a primary discharging capacitor connected to an output of said DC-DC converter circuit; and a flashing discharge lamp connected in parallel with said primary discharging capacitor; said first switching means serving to connect said primary cell and said plurality of secondary cells in parallel before said DC-DC converter circuit is operated in order to charge said plurality of secondary cells with said primary cell while connecting said plurality of secondary cells in series during the operation of said DC-DC converter circuit in order to rapidly charge said primary discharging capacitor.
Claim 2
Dependent Claim
206 words
A photographic flash apparatus comprising: a power supply means including a plurality of rechargeable secondary cells for supplying a large discharging current to a load, a primary cell, connectable to said plurality of secondary cells, havig a small self-discharging factor and a terminal voltage higher than a final charge voltage of said secondary cells, and a first switching means for connecting said primary cell to said plurality of secondary cells; a DC-DC converter circuit including an oscillating transistor having base, emitter and collector terminals, an oscillation transformer connected to said oscillating transistor and a second switching means connected to said oscillating transistor; said power supply means being connected to an input of said DC-DC converter circuit; a primary discharging capacitor connected to an output of said DC-DC converter circuit; and a flashing discharge lamp connected in parallel with said primary discharging capacitor; said first switching means serving to connect said primary cell and said plurality of secondary cells in parallel before said DC-DC converter circuit is operated in order to charge said plurality of secondary cells with said primary cell while connecting said plurality of secondary cells in series during the operation of said DC-DC converter circuit in order to rapidly charge said primary discharging capacitor.
Claim 3
Dependent Claim
24 words
A photographic flash apparatus according to claim 1 wherein said secondary cells comprise nickel cadmium cells and said primary cell comprises a manganese cell.
Claim 4
Dependent Claim
30 words
A photographic flash apparatus according to claim 1 wherein said second switching means comprises a semiconductor switching device which controls current flowing into the base terminal of said oscillating transistor.
Claim 5
Dependent Claim
16 words
A photographic flash apparatus according to claim 3 wherein said semiconductor switching device comprises a thyristor.
Claim 6
Dependent Claim
22 words
A photographic flash apparatus according to claim 3 wherein said oscillation transformer is connected to the collector terminal of said oscillating transistor.
Claim 7
Dependent Claim
25 words
A photographic flash apparatus according to claim 1, wherein said first switch means comprises a sliding contact associated with the shutter release of a 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) | 1980-08-01 | 1981-01-31 | 1981-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-01 | 1985-01-31 | 1985-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-01 | 1989-01-31 | 1989-08-02 | $7700.00 | Window Closed / Lapsed |