US3729610A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical discharge machining device using logical control
Assignee: Individual
•
Filing: 1971-11-22
•
Granted: 1973-04-24
•
Expires: 1991-11-22
Abstract
Abstract An automatic electrical discharge machining device, including a logic circuit and detecting units monitoring voltages and currents at different parts of the machining device circuit. The detecting units deliver their outputs to the logic circuit, for determining the short -circuit, large gap conductance, sustained arcing, and other detrimental conditions at the discharge gap, by suitably combining the outputs from the detecting units. Automatic control is made in response to the output from the logic circuit for regulating an electrode or various voltage pulses.
Inventors
- 👤 I Kondo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:59
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02; B23H1/024
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
120 words
Device for machining a conductive workpiece by means of intermittent discharge of a relatively large electric pulse added to a relatively small electric pulse for insulation breakingthrough to be applied across a gap between said workpiece and a movable electrode, comprising at least two means for detecting high voltage and low current of said small pulse for breakthrough and low output voltage and high output current of said large pulse for machining separately and independently in the discharge machining circuit, and logic circuit means for analyzing the detected values in combination to produce at least one signal representing any of normal machining condition, nondischarge condition, short circuit condition and gap conductance condition to be utilized for controlling the machining automatically.
Claim 2
Dependent Claim
120 words
Device for machining a conductive workpiece by means of intermittent discharge of a relatively large electric pulse added to a relatively small electric pulse for insulation breakingthrough to be applied across a gap between said workpiece and a movable electrode, comprising at least two means for detecting high voltage and low current of said small pulse for breakthrough and low output voltage and high output current of said large pulse for machining separately and independently in the discharge machining circuit, and logic circuit means for analyzing the detected values in combination to produce at least one signal representing any of normal machining condition, nondischarge condition, short circuit condition and gap conductance condition to be utilized for controlling the machining automatically.
Claim 3
Dependent Claim
31 words
Device as claimed in claim 1, including means for detecting gap conductance, and means responsive to detected conductance for withdrawing said electrode from the workpiece so as to eliminate said conductance.
Claim 4
Dependent Claim
119 words
Device as claimed in claim 1, further comprising means for superimposing high voltage pulses providing for insulation breakthrough on low voltage pulses for machining in phase, said means being adapted to produce intermittently interrupted pulses to generate m pulses in every n successive actuating pulses, wherein n is a positive integer of at least 2 and m is a positive integer of (n - 1) at the most, consisting only of said low voltage pulses, and logic circuit means for subjecting to logic analysis the detected value of said intermittently lacking pulses together with said separately and independently detected values to produce a further signal representing undesirable sustained arcing condition to be utilized for controlling the machining more precisely.
Claim 5
Dependent Claim
64 words
Device as claimed in claim 1, further comprising means for superimposing high voltage pulses on low voltage pulses out of phase, and logic circuit means for subjecting to logic analysis the detected value of said resulting pulses together with said separately and independently detected values to produce a further signal representing undesirable sustained arcing condition to be utilized for controlling the machining more precisely.
Claim 6
Dependent Claim
38 words
Device as claimed in claim 4, further comprising means for narrowing the pulse width of the subsequent pulses applied across the gap in response to the detection of the undesirable arcing condition in respect to the preceding pulses.
Claim 7
Dependent Claim
50 words
Device as claimed in claim 4, further comprising means for preventing at least each one of subsequently occuring high and low voltage pulses from entering said superimposing means to form intermittently lacking pulses in response to the detection of the undesirable sustained arcing condition in respect to the preceding pulses.
Claim 8
Dependent Claim
39 words
Device as claimed in claim 4, further comprising means for lowering the maximum current value of low voltage electric pulses for machining in response to the detection of the undesirable sustained arcing condition in respect to the preceding pulses.
Claim 9
Dependent Claim
85 words
Device as claimed in claim 1, further comprising means for counting the number of discharges per unit of time only during the normal machining condition to be detected by said logic circuit means, means for determining an electrode Feed during said unit time period, and means for subjecting to logic analysis the value of said determined electrode feed to produce a further signal of the value as a function of the effective area of the electrode to be utilized for controlling the machining more precisely.
Claim 10
Dependent Claim
32 words
Device as claimed in claim 8, in which any of the maximum value of peak pulse current and the duty factor thereof is automatically determined depending on said electrode area function value.
References Cited (Backward Citations)
US3604885A
Cited
US3590205A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-23 | 1976-10-23 | 1977-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-23 | 1980-10-23 | 1981-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-23 | 1984-10-23 | 1985-04-24 | $7700.00 | Window Closed / Lapsed |