US3757073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark erosion constant current density method of machining a work piece by means of
Assignee: US Philips Corp
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Filing: 1971-01-21
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Granted: 1973-09-04
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Expires: 1991-01-21
Abstract
Abstract A method and a device for machining a work-piece by means of spark erosion are described, in which a breakdown is produced in a discharge space formed by the work-piece and a tool electrode which are connected to a supply source. It is shown that the current density in the discharge space may be maintained substantially constant by switching a stabilized voltage source across the discharge space at the instant of breakdown.
Inventors
- 👤 Osenbruggen C Van
- 👤 Der Veeke A Van
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:30
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/022; B23H2300/00; B23H2300/20
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
73 words
A method of machining a work-piece by means of spark erosion comprising the steps of first producing a voltage breakdown in the discharge space between the workpiece and a spark electrode by applying a voltage across said discharge space, and thereafter connecting a stabilized voltage source to the discharge space at the instant of breakdown so that the electric current density through a discharge channel in the discharge space is maintained substantially constant.
Claim 2
Independent Claim
73 words
A method of machining a work-piece by means of spark erosion comprising the steps of first producing a voltage breakdown in the discharge space between the workpiece and a spark electrode by applying a voltage across said discharge space, and thereafter connecting a stabilized voltage source to the discharge space at the instant of breakdown so that the electric current density through a discharge channel in the discharge space is maintained substantially constant.
Claim 3
Dependent Claim
74 words
A spark erosion device for electrically machining a workpiece comprising, an electrode adapted to be positioned adjacent the workpieCe to define therewith a spark discharge space, a stabilized source of voltage, means for producing a breakdown in said discharge space, and means for connecting said stabilized voltage source across the discharge space at the instant of breakdown whereby the electric current density through a discharge channel in the discharge space is maintained substantially constant.
Claim 4
Dependent Claim
74 words
A spark erosion device for electrically machining a workpiece comprising, an electrode adapted to be positioned adjacent the workpieCe to define therewith a spark discharge space, a stabilized source of voltage, means for producing a breakdown in said discharge space, and means for connecting said stabilized voltage source across the discharge space at the instant of breakdown whereby the electric current density through a discharge channel in the discharge space is maintained substantially constant.
Claim 5
Dependent Claim
53 words
A device as claimed in claim 2 further comprising means for deriving a control signal from the voltage across the discharge space, and control circuit means responsive to the control signal for operating said connecting means to cause the voltage supplied by the stabilized voltage source to be applied across the discharge space.
Claim 6
Dependent Claim
45 words
A device as claimed in claim 3 wherein said connecting means comprises a switching member connected in circuit with the stabilized voltage source and the discharge space, and said control circuit means comprises a monostable multivibrator connected between the switching member and the discharge space.
Claim 7
Dependent Claim
22 words
A device as claimed in claim 4, characterized in that an amplifier is connected between the monostable multivibrator and the switching member.
Claim 8
Dependent Claim
20 words
A device as claimed in claim 5, characterized in that the amplifier comprises two cascaded transistors connected as emitter followers.
Claim 9
Dependent Claim
26 words
A device as claimed in claim 4 wherein said control circuit means further comprises a bistable multivibrator connected between the discharge space and the monostable multivibrator.
Claim 10
Dependent Claim
49 words
A device as claimed in claim 3 further comprising means for deriving a second control signal from the voltage across the discharge space, and means responsive to the second control signal for controlling the amplitude of the voltage set up across the discharge space by the stabilized voltage source.
Claim 11
Dependent Claim
57 words
A device as claimed in claim 8 further comprising a differential amplifier connected between the monostable multivibrator and the switching member and one input of which is connected to a reference voltage source, and means connecting a second input of said amplifier to a voltage divider connected across the discharge space to derive said second control signal.
Claim 12
Dependent Claim
43 words
A device as claimed in claim 8 wherein said connecting means comprises a switching member connected between the stabilized voltage source and the discharbe space, and said control circuit means comprises a monostable multivibrator connected between the switching member and the discharge space.
Claim 13
Dependent Claim
17 words
A device as claimed in claim 3 wherein said control signal deriving means includes a differentiating network.
Claim 14
Dependent Claim
68 words
A device as claimed in claim 2 wherein said connecting means comprises a controlled switching member connected in series circuit with said stabilized voltage source and said discharge space, said device further comprising means responsive to the voltage across the discharge space for producing a control signal that operates said switching member at the instant of breakdown and maintains said switching member operated for a predetermined time period.
Claim 15
Dependent Claim
54 words
A device as claimed in claim 12 further comprising means responsive to the voltage across the discharge space for deriving a second control signal that varies the impedance of the switching member as a function thereof thereby to control the amplitude of the voltage developed across the discharge space by the stabilized voltage source.
Claim 16
Dependent Claim
60 words
A device as claimed in claim 13 wherein said breakdown producing means comprises a pulse generator that supplies voltage pulses that are of short duration relative to said predetermined time period, and wherein the input circuit of said second control signal deriving means includes means for limiting the amplitude of the input signal applied thereto from across the discharge space.
Claim 17
Dependent Claim
87 words
A spark erosion device for electrically machining a workpice comprising, an electrode adapted to be positioned adjacent the workpice to define therewith a spark discharge gap, a stabilized source of constant voltage, means for applying a predetermined voltage to said discharge gap to produce a breakdown therein, and means for selectively connecting said stabilized voltage source across the discharge gap in response to and at the instant of gap breakdown whereby the electric current density through a discharge channel in the discharge gap is maintained substantially constant.
Claim 18
Dependent Claim
87 words
A spark erosion device for electrically machining a workpice comprising, an electrode adapted to be positioned adjacent the workpice to define therewith a spark discharge gap, a stabilized source of constant voltage, means for applying a predetermined voltage to said discharge gap to produce a breakdown therein, and means for selectively connecting said stabilized voltage source across the discharge gap in response to and at the instant of gap breakdown whereby the electric current density through a discharge channel in the discharge gap is maintained substantially constant.
Claim 19
Dependent Claim
25 words
A device as claimed in claim 15 wherein said stabilized voltage source comprises a capacitor and means for charging the capacitor in a non-resonant manner.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |