US3564339A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for rapid shutoff of electrochemical machining apparatus
Assignee: KMS Industries Inc
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Filing: 1969-10-31
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Granted: 1971-02-16
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Expires: 1989-10-31
Abstract
Abstract A circuit for the rapid turnoff of the load current in an electrochemical machining apparatus is disclosed. The approach employed is to shunt the load current through an SCR after a short circuit has been detected. The circuit operates to induce an additional voltage in the load circuit to reduce the load current to zero for a sufficient length of time to permit the SCR''s in series with the load to recover their blocking capability.
Inventors
- 👤 Harold W Katz
- 👤 Murray H Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:30
CPC Classifications
B; B23; B23H; B23H3/00; B23H3/02; H; H02; H02H; H02H3/00; H02H3/02; H02H3/021; H02H3/023
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
96 words
A circuit for the rapid shutoff of load current to a machine, comprising: a. means for detecting a short circuit condition in the machine and producing a triggering output; b. electronic switch means connected in shunt with the machine and responsive to said triggering output of said detecting means to be triggered ''''on'''' when a short circuit is detected; and c. means responsive to said triggering output for producing an additional voltage in the load circuit to reduce the load current to the machine to zero thereby establishing the shunt circuit through said electronic switch means.
Claim 2
Dependent Claim
96 words
A circuit for the rapid shutoff of load current to a machine, comprising: a. means for detecting a short circuit condition in the machine and producing a triggering output; b. electronic switch means connected in shunt with the machine and responsive to said triggering output of said detecting means to be triggered ''''on'''' when a short circuit is detected; and c. means responsive to said triggering output for producing an additional voltage in the load circuit to reduce the load current to the machine to zero thereby establishing the shunt circuit through said electronic switch means.
Claim 3
Dependent Claim
57 words
A circuit as recited in claim 1 wherein said electronic switch means is an SCR and further comprising a second SCR connected in series with said machine and normally conducting the load current, and wherein the voltage produced by said voltage producing means has a duration sufficient to enable said second SCR to recover its blocking capabilities.
Claim 4
Dependent Claim
62 words
A circuit as recited in claim 1 wherein said voltage producing means comprises: a. transformer means having at least first and second windings, said first winding being connected in series with said machine; and b. pulse producing means connected to said second winding for inducing a voltage pulse in said first winding in response to the triggering output of said detecting means.
Claim 5
Dependent Claim
47 words
A circuit as recited in claim 3 wherein said transformer means includes a core of square hysteresis loop material and a third winding wound thereon, and further comprising biasing means connected to said third winding for biasing the core towards saturation in opposition to the load current.
Claim 6
Dependent Claim
28 words
A circuit as recited in claim 3 wherein said pulse producing means comprises: a. pulse forming means; and b. a discharge circuit connected to said pulse forming means.
Claim 7
Dependent Claim
34 words
A circuit as recited in claim 5 wherein said pulse forming means comprises a plurality of parallel-connected inductors and capacitors connected in series between one end of said second winding and said discharge circuit.
Claim 8
Dependent Claim
58 words
A circuit as recited in claim 6 wherein said discharge circuit comprises: a. a capacitor connected across a source of charging current; and b. an SCR connected between said source of charging current and the other end of said second winding and responsive to said triggering output to cause said capacitor to discharge through said pulse forming means.
Claim 9
Dependent Claim
66 words
A circuit as recited in claim 1 wherein said detecting means comprises: a. a voltage divider connected across the machine, b. normally nonconducting means connected to said voltage divider and responsive to a short circuit condition in said machine to become fully conductive, and c. triggering means connected to said normally nonconducting means for initiating said trigering output when said normally nonconducting means becomes fully conductive.
Claim 10
Dependent Claim
92 words
A circuit as recited in claim 1 further comprising: a. pulse generating means responsive to said triggering output for generating two series of pulses, one of said series being connected to said electronic switch means and means for producing an additional voltage; and b. means responsive to the other one of said two series of pulses for producing a second voltage connected in series with said electronic switch means and in shunt with the machine whereby the load current is pulsed back and forth between the machine and the electronic switch means.
Claim 11
Dependent Claim
91 words
A circuit as recited in claim 9 wherein said electronic switch means is an SCR and further comprising a second SCR connected in series with said machine and connected to triggered ''''on'''' by said other one of said two series of pulses, and wherein the voltage produced by said additional voltage producing means has a duration sufficient to enable said second SCR to recover its blocking capabilities and the voltage produced by said second voltage producing means has a duration sufficient to enable the first SCR to recover its blocking capabilities.
Claim 12
Dependent Claim
31 words
A circuit as recited in claim 10 wherein said additional voltage producing means and said second voltage producing means are magnetic circuits comprising transformers including cores of square hysteresis loop material.
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) | 1974-02-15 | 1974-08-17 | 1975-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-15 | 1978-08-17 | 1979-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-15 | 1982-08-17 | 1983-02-16 | $7700.00 | Window Closed / Lapsed |