Patent US3864541A successfully refreshed from Google Patents.
US3864541A
Expired / Lapsed
US
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System for the controlling of an apparatus for the electric discharge machining etc.
Assignee: Japan Kinoko Research Center Foundation
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Filing: 1973-10-23
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Granted: 1975-02-04
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Expires: 1993-10-23
Abstract
Abstract Discrete electric-discharge pulses are applied across a dielectric-swept gap between an electrode and a workpiece by triggering an ON-OFF switch between its conductive and nonconductive states in accordance with parameters of the gap so that per pulse adaptive control of the individual machining discharges is effected. An integrator responsive to the gap current, may be used to operate the switch means which may be turned on upon the detection of a pilot discharge. The number of unsatisfactory discharges is detected and, if this number exceeds a predetermined level, is used to control a gap parameter. The integrator signal may be digitalized for accumulation in a counter controlling pulse duration and other parameters.
Inventors
- 👤 Kiyoshi Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:39
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/022; B23H1/024; B23H7/00; B23H7/14; B23H7/16; B23H7/18; B23H2300/00; B23H2300/20
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
161 words
In an electric discharge machining apparatus in which a tool electrode is spacedly juxtaposed with a workpiece electrode across a dielectric-swept gap, the improvement which comprises: a source of machining current connected to said electrodes; on-off switch means in circuit with said source and said electrodes and adapted to be rendered conductive and nonconductive selectively by a gating signal to apply a voltage pulse to said gap, thereby effecting an electrical discharge between said electrodes; means for deriving an analog signal representing the current traversing said gap; converter circuit means for transforming said analog signal into a train of digital pulses of a frequency proportional to said analog signal; a counter for counting said digital pulses and producing an output signal upon the number of digital pulses detected by said counter attaining a predetermined number; and a gate circuit connected to said counter and operated by said signal for terminating said gating signal to said switch means to terminate the discharge.
Claim 2
Dependent Claim
161 words
In an electric discharge machining apparatus in which a tool electrode is spacedly juxtaposed with a workpiece electrode across a dielectric-swept gap, the improvement which comprises: a source of machining current connected to said electrodes; on-off switch means in circuit with said source and said electrodes and adapted to be rendered conductive and nonconductive selectively by a gating signal to apply a voltage pulse to said gap, thereby effecting an electrical discharge between said electrodes; means for deriving an analog signal representing the current traversing said gap; converter circuit means for transforming said analog signal into a train of digital pulses of a frequency proportional to said analog signal; a counter for counting said digital pulses and producing an output signal upon the number of digital pulses detected by said counter attaining a predetermined number; and a gate circuit connected to said counter and operated by said signal for terminating said gating signal to said switch means to terminate the discharge.
Claim 3
Dependent Claim
30 words
The improvement defined in claim 1, further comprising means for selecting the number of such pulses to be accumulated in said counter prior to the formation of said output signal.
Claim 4
Dependent Claim
60 words
The improvement defined in claim 1, further comprising a timer establishing a predetermined duration representing a time interval between successive voltage pulses and means responsive to said timer and the rate of accumulation of pulses in said counter for increasing said interval upon said rate of accumulation of pulses exceeding predetermined value indicating the development of an unsatisfactory gap condition.
Claim 5
Dependent Claim
66 words
The improvement defined in claim 3, wherein the last-mentioned means includes a second timer establishing a second predetermined duration representing a minimum duration for discharge normally sufficient to enable said gap to recover from a previous discharge, a delay circuit connected between the first-mentioned timer and said gating means, and further gating means connected between said counter and said second timer for controlling said delay circuit.
Claim 6
Dependent Claim
128 words
In a system for the electric discharge machining of a workpiece by an electrode juxtaposed therewith across a dielectric-filled gap, the improvement which comprises, in combination: an electric-current source; ON-OFF switch means connected in circuit with said source, said workpiece and said electrode and triggerable to apply a substantially rectangular-wave machining current pulse to said gap to effect electrical discharge thereacross; detector means responsive to a current flow through said gap for producing an analog voltage; an analog-digital converter connected to said detector for producing a train of pulses and of a frequency determined by said voltage; a counter for registering said pulses; and means responsive to sAid counter for controlling said switch means to terminate the machining current pulse upon the registered count reaching a preset value.
Claim 7
Dependent Claim
128 words
In a system for the electric discharge machining of a workpiece by an electrode juxtaposed therewith across a dielectric-filled gap, the improvement which comprises, in combination: an electric-current source; ON-OFF switch means connected in circuit with said source, said workpiece and said electrode and triggerable to apply a substantially rectangular-wave machining current pulse to said gap to effect electrical discharge thereacross; detector means responsive to a current flow through said gap for producing an analog voltage; an analog-digital converter connected to said detector for producing a train of pulses and of a frequency determined by said voltage; a counter for registering said pulses; and means responsive to sAid counter for controlling said switch means to terminate the machining current pulse upon the registered count reaching a preset value.
Claim 8
Dependent Claim
19 words
The improvement defined in claim 5 wherein a frequency divider is provided between said analog-digital converter and said counter.
Claim 9
Dependent Claim
89 words
The improvement defined in claim 6, further comprising a second counter for controlling one of the states of said switch means, a clock-pulse generator for producing a train of clock pulses, and a second frequency divider between said clock-pulse generator and said second counter for resetting the first-mentioned counter upon the number of clock pulses registered in said second counter attaining a preset value, said first counter being connected to said second counter for resetting same upon the counts registered in said first counter attaining the value preset therein.
Claim 10
Dependent Claim
57 words
The improvement defined in claim 6 wherein last-mentioned means is a flip-flop having a reset terminal connected to said counter, further comprising a delay circuit connected between said counter and a set terminal of said flip-flop for switching the state of said flip-flop upon the lapse of a predetermined interval following the switching thereof by said counter.
Claim 11
Dependent Claim
18 words
The improvement defined in claim 6 wherein said detector is a resistor connected in series with said gap.
Claim 12
Dependent Claim
20 words
The improvement defined in claim 9 wherein said resistor is connected in series with said gap and said electric-current source.
Claim 13
Dependent Claim
29 words
The improvement defined in claim 9, further comprising an auxiliary direct-current source connected in parallet with said electric current source and in series with said resistor across said gap.
Claim 14
Dependent Claim
52 words
The improvement defined in claim 11 wherein said auxiliary current source has direct-current output voltage sufficient to effet dielectric breakdown of the machining gap and initiating machining discharge, further comprising means responsive to gap voltage for shunting the auxiliary source from said gap upon the gap voltage falling below a predetermined value.
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) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |