Patent US151315A successfully refreshed from Google Patents.
US3746930A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for detecting arcs
Assignee: US Philips Corp
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Filing: 1971-06-14
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Granted: 1973-07-17
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Expires: 1991-06-14
Abstract
Abstract Apparatus for detecting the occurrence of an arc during a spark erosion process is based upon the principle that the noise component of the voltage across the discharge gap disappears when an arc occurs. The noise voltage is detected and compared with a reference voltage in a discriminator circuit. A signal from a logic circuit is also applied to the discriminator which determines the presence of a current through, and of a voltage across, the spark discharge gap.
Inventors
- 👤 Zeeuw J De
- 👤 Best J Van
- 👤 E Avenarius
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:34
CPC Classifications
B; B23; B23H; B23H1/00; B23H1/02
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
123 words
EDM apparatus having means for the detection of arcs during a spark erosion process in which spark diScharges are produced in a discharge space constituted by a workpiece and a tool electrode comprising, means for connecting said workpiece and tool electrode to a supply source, means connecting the discharge space defined by said workpiece and electrode to the input terminals of a noise detection circuit for detecting the noise component of the voltage developed across the discharge space during a spark erosion operation, a discriminator circuit, means connecting the output terminals of the noise detection circuit to the input circuit of said discriminator circuit, a reference voltage supply, and means connecting the input circuit of the discriminator circuit to said reference voltage supply.
Claim 2
Dependent Claim
123 words
EDM apparatus having means for the detection of arcs during a spark erosion process in which spark diScharges are produced in a discharge space constituted by a workpiece and a tool electrode comprising, means for connecting said workpiece and tool electrode to a supply source, means connecting the discharge space defined by said workpiece and electrode to the input terminals of a noise detection circuit for detecting the noise component of the voltage developed across the discharge space during a spark erosion operation, a discriminator circuit, means connecting the output terminals of the noise detection circuit to the input circuit of said discriminator circuit, a reference voltage supply, and means connecting the input circuit of the discriminator circuit to said reference voltage supply.
Claim 3
Dependent Claim
48 words
Apparatus as claimed in claim 1 further comprising a logic circuit having input terminals coupled to receive the voltage set up across, and the current flowing through, the discharge space, and means connecting the output of the logic circuit to the output terminals of the noise detection circuit.
Claim 4
Dependent Claim
38 words
Apparatus as claimed in claim 2 further comprising a controlled switch connected between the output terminals of the noise detection circuit, and means connecting a control circuit of the switch to the output terminals of the logic circuit.
Claim 5
Dependent Claim
39 words
Apparatus as claimed in claim 1 wherein the discriminator circuit comprises an operational amplifier having one input terminal connected to an output terminal of the noise detection circuit and the other input terminal connected to said reference voltage supply.
Claim 6
Dependent Claim
69 words
Apparatus as claimed in claim 1 with a protection device for suppressing arcs during a spark erosion process including an apparatus as claimed in any of the preceding Claims, and comprising a switching device for disconnecting the supply source from the workpiece and electrode, and means connecting the output terminals of the discriminator circuit to said switching device for switching off the supply source when an arc is detected.
Claim 7
Dependent Claim
34 words
A protection device as claimed in claim 5 further comprising a pulse counter with its input connected to the output terminals of the discriminator circuit and its output coupled to control said switching device.
Claim 8
Dependent Claim
45 words
A protection device as claimed in claim 5 further comprising an integrating network with an input circuit connected to the output terminals of the discriminator circuit and an output circuit, said switching device comprising a relay connected to the output circuit of the integrating network.
Claim 9
Dependent Claim
80 words
Apparatus as claimed in claim 1 further comprising a gating circuit having an input and an output, means for coupling first and second signals to said gating circuit input that are determined respectively by the voltage across and the current flowing through the discharge space, and means connecting the gate output to the output terminals of the noise detection circuit in a manner such that the discriminator circuit is jointly controlled by the gate circuit and the noise detection circuit.
Claim 10
Dependent Claim
39 words
Apparatus as claimed in claim 8 wherein the discriminator circuit comprises an operational amplifier having one input terminal connected to an output terminal of the noise detection circuit and a second input terminal connected to said reference voltage supply.
Claim 11
Dependent Claim
75 words
Apparatus as claimed in claim 8 further comprising arc suppression means including a switching device for controlling the supply of electric energy from the supply source to the discharge space, and means connecting the output of the discriminator circuit to an input of the switching device whereby the switching device is operated to block the energy flow to said discharge space when the discriminator output signals the presence of an arc across said discharge space.
Claim 12
Dependent Claim
30 words
Apparatus as claimed in claim 10 wherein said last-named connecting means comprises an integrating network coupled between the output of the discriminator circuit and the input of the switching device.
Claim 13
Dependent Claim
53 words
Apparatus as claimed in claim 8 further comprising a controlled switching element connected across tHe output terminals of the noise detection circuit, and means connecting a control terminal of the switching element to the output of the gating circuit whereby the condition of the gating circuit controls the state of the switching element.
Claim 14
Dependent Claim
31 words
Apparatus as claimed in claim 8 wherein said noise detection circuit comprises an RC differentiating network and a diode coupling said RC network to the input circuit of the discriminator circuit.
Claim 15
Dependent Claim
104 words
A spark erosion apparatus having means for detecting the presence of an arc between a workpiece and a tool electrode comprising, an electric power supply coupled to the workpiece and tool electrode for producing electric spark discharges across the gap formed by the workpiece and tool electrode, first means connected to the workpiece and tool for detecting the noise component of the gap voltage, second means for detecting the presence or absence of a current flow across said gap, and control means coupled to said first and second detecting means for producing a control signal determined by the noise voltage and the gap current.
Claim 16
Dependent Claim
104 words
A spark erosion apparatus having means for detecting the presence of an arc between a workpiece and a tool electrode comprising, an electric power supply coupled to the workpiece and tool electrode for producing electric spark discharges across the gap formed by the workpiece and tool electrode, first means connected to the workpiece and tool for detecting the noise component of the gap voltage, second means for detecting the presence or absence of a current flow across said gap, and control means coupled to said first and second detecting means for producing a control signal determined by the noise voltage and the gap current.
Claim 17
Dependent Claim
46 words
Apparatus as claimed in claim 14 further comprising a controlled switching element responsive to said second detecting means and connected in circuit with said first detecting means to control the level of the noise voltage as a function of the presence or absence of gap current.
Claim 18
Dependent Claim
49 words
Apparatus as claimed in claim 14 further comprising third means connected to the workpiece and tool electrode for detecting the gap voltage, and means for coupling the output of said third detecting means to the control means so that said control signal is further determined by the gap voltage.
References Cited (Backward Citations)
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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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |