US3655936A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for electroerosively etching a workpiece
Assignee: Mitsubishi Electric Corp
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Filing: 1971-01-25
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Granted: 1972-04-11
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Expires: 1991-01-25
Abstract
Abstract A circuit for an electroerosive etching apparatus is disclosed which includes first and second direct current sources controlled by first and second switching circuits, respectively. The first switching circuit includes a plurality of switching elements, all of which are connected in parallel to facilitate the delivery of large currents and a pulse source for controlling the switching elements. The second switching circuit may include only one switching element, and is designed to supply only small currents. In operation, the first and second switching circuits initially cooperate to apply a potential nearly equal to the combined potentials of the two direct current sources across a working gap. Once a discharge is achieved using this high potential, the second switching circuit is automatically cut off, leaving the first switching circuit operative to supply the large current needed in the etching operation. A protective circuit is also included to prevent damage of the first switching circuit due to overloading.
Inventors
- 👤 Nagao Saito
- 👤 Kazuhiko Kobayashi
- 👤 Susumu Niwa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:36
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/022
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
185 words
A circuit for an electroerosive etching apparatus comprising: main circuit means, said main circuit means including first power source means, first switching means coupled to said first power source means, first diode means coupled in series with said first switching means, electrode means, and, said first power source means and said first switch means adapted to be coupled to a workpiece, said electrode means arranged to be separated from said workpiece by a working gap, auxiliary circuit means coupled to said main circuit means, said auxiliary circuit means including second power source means, and, second switching means coupled to said second power source means, said intercoupled second power source means and second switch means coupled in parallel with said first diode means, whereby said combined main and auxiliary circuits are automatically responsive to conditions existing at said working gap such that when said first switch means is in its conductive state, said second switch means is in its conductive state until a current flows in said working gap but when a current flows in said gap said second switch means switches to its non-conductive state.
Claim 2
Dependent Claim
185 words
A circuit for an electroerosive etching apparatus comprising: main circuit means, said main circuit means including first power source means, first switching means coupled to said first power source means, first diode means coupled in series with said first switching means, electrode means, and, said first power source means and said first switch means adapted to be coupled to a workpiece, said electrode means arranged to be separated from said workpiece by a working gap, auxiliary circuit means coupled to said main circuit means, said auxiliary circuit means including second power source means, and, second switching means coupled to said second power source means, said intercoupled second power source means and second switch means coupled in parallel with said first diode means, whereby said combined main and auxiliary circuits are automatically responsive to conditions existing at said working gap such that when said first switch means is in its conductive state, said second switch means is in its conductive state until a current flows in said working gap but when a current flows in said gap said second switch means switches to its non-conductive state.
Claim 3
Dependent Claim
34 words
A circuit as in claim 1, wherein: said first and second power source means are coupled in series across said working gap when said first and second switch means are in their conductive states.
Claim 4
Dependent Claim
23 words
A circuit as in cLaim 1, wherein: means are provided in said main circuit means for protecting said first switching means against overloads.
Claim 5
Dependent Claim
13 words
A circuit as in claim 3, wherein: said protecting means comprises a diode.
Claim 6
Dependent Claim
34 words
A circuit as in claim 1, wherein: said first switching means includes a plurality of transistors, and a pulse source coupled to said transistors for switching said transistors between their conductive and non-conductive states.
Claim 7
Dependent Claim
24 words
A circuit as in claim 1, wherein: said second switching means switches in response to the magnitude of the voltage across said working gap.
Claim 8
Dependent Claim
40 words
A circuit as in claim 6, wherein: said second switching means includes a transistor, and a zener diode, said zener diode coupled between said transistor and said working gap for sensing the magnitude of the voltage across said working gap.
Claim 9
Dependent Claim
40 words
A circuit as in claim 1, wherein said first power source means has a first output voltage and said second power source means has a second output voltage, and said second output voltage is larger than said first output voltage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |