US4126841A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overcurrent switch
Assignee: Fujitsu Ltd
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Filing: 1977-06-30
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Granted: 1978-11-21
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Expires: 1997-06-30
Abstract
Abstract An overcurrent switch is described, comprising a reed switch for series connection in an electric circuit to break the flow of an overcurrent therethrough. A magnetizing element applies a magnetic field to the reed switch, and a setting device controls the magnetic field so that at least two levels of magnetic field intensity are selectively applied to the reed switch.
Inventors
- 👤 Chiaki Maeno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:25
CPC Classifications
H; H01; H01H; H01H77/00; H01H77/02; H01H77/06; H01H77/08; H01H71/00; H01H71/10; H01H71/12; H01H71/24; H01H71/2445
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
225 words
In an overcurrent switch serially connected in a circuit for interrupting the flow of current therethrough when an overcurrent is detected, the switch comprising: a pair of electrically conductive contacts actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level; and first means for initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position, and for subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain said pair of contacts in said closed position; the improvement wherein said pair of electrically conductive contacts are selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; said overcurrent switch comprising second means for applying said flow of current solely and directly to said pair of contacts whereby, when said overcurrent occurs, said dropout level rises to said intermediate level and said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 2
Dependent Claim
225 words
In an overcurrent switch serially connected in a circuit for interrupting the flow of current therethrough when an overcurrent is detected, the switch comprising: a pair of electrically conductive contacts actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level; and first means for initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position, and for subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain said pair of contacts in said closed position; the improvement wherein said pair of electrically conductive contacts are selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; said overcurrent switch comprising second means for applying said flow of current solely and directly to said pair of contacts whereby, when said overcurrent occurs, said dropout level rises to said intermediate level and said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 3
Dependent Claim
92 words
In an overcurrent switch as recited in claim 1 wherein said first means comprises a permanent magnet, and means for advancing said permanent magnet to a first position of sufficient proximity to said pair of contacts so as to apply said magnetic field of intensity equal to at least said predetermined pull-in level, and for withdrawing said permanent magnet to a second position less proximate to said pair of contacts than said first position so as to apply a magnetic field of said intensity intermediate between said drop-out and said pull-in levels.
Claim 4
Dependent Claim
86 words
In an overcurrent switch as recited in claim 1 wherein said first means comprises a permanent magnet fixedly located in proximity to said pair of contacts for providing thereto a magnetic field of said intensity intermediate between said drop-out and said pull-in levels, and means for applying to said pair of contacts a magnetic field of additional intensity, said additional intensity plus said intensity intermediate between said drop-out and said pull-in levels equaling said magnetic field of intensity equal to at least said predetermined pull-in level.
Claim 5
Dependent Claim
221 words
In an overcurrent switch serially connected in a circuit for interrupting the flow of current therethrough when a overcurrent is detected, the switch comprising: a pair of electrically conductive contacts actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level; and first means for initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position, and for subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain said pair of contacts in said closed position; the improvement wherein said pair of electrically conductive contacts are selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; said overcurrent switch comprising second means for raising said drop-out level to said intermediate level by applying said flow of current solely and directly to said pair of contacts, whereby said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 6
Dependent Claim
221 words
In an overcurrent switch serially connected in a circuit for interrupting the flow of current therethrough when a overcurrent is detected, the switch comprising: a pair of electrically conductive contacts actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level; and first means for initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position, and for subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain said pair of contacts in said closed position; the improvement wherein said pair of electrically conductive contacts are selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; said overcurrent switch comprising second means for raising said drop-out level to said intermediate level by applying said flow of current solely and directly to said pair of contacts, whereby said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 7
Dependent Claim
92 words
In an overcurrent switch as recited in claim 4 wherein said first means comprises a permanent magnet, and means for advancing said permanent magnet to a first position of sufficient proximity to said pair of contacts so as to apply said magnetic field of intensity equal to at least said predetermined pull-in level, and for withdrawing said permanent magnet to a second position less proximate to said pair of contacts than said first position so as to apply a magnetic field of said intensity intermediate between said drop-out and said pull-in levels.
Claim 8
Dependent Claim
86 words
In an overcurrent switch as recited in claim 4 wherein said first means comprises a permanent magnet fixedly located in proximity to said pair of contacts for providing thereto a magnetic field of said intensity intermediate between said drop-out ans said pull-in levels, and means for applying to said pair of contacts a magnetic field of additional intensity, said additional intensity plus said intensity intermediate between said drop-out and said pull-in levels equaling said magnetic field of intensity equal to at least said predetermined pull-in level.
Claim 9
Independent Claim
218 words
A method of interrupting the flow of current through a circuit when an overcurrent is detected, comprising the steps of: (a) providing a pair of electrically conductive contacts serially connected in said circuit and actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level, said pair of electrically conductive contacts being selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; (b) initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position; (c) subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain the pair of contacts in said closed position; and (d) applying said flow of current solely and directly to said pair of contacts whereby, when said overcurrent occurs, said drop-out level is increased to said intermediate level and said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 10
Independent Claim
218 words
A method of interrupting the flow of current through a circuit when an overcurrent is detected, comprising the steps of: (a) providing a pair of electrically conductive contacts serially connected in said circuit and actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level, said pair of electrically conductive contacts being selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; (b) initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position; (c) subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain the pair of contacts in said closed position; and (d) applying said flow of current solely and directly to said pair of contacts whereby, when said overcurrent occurs, said drop-out level is increased to said intermediate level and said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 11
Independent Claim
213 words
A method of interrupting the flow of current through a circuit when an overcurrent is detected, comprising the steps of: (a) providing a pair of electrically conductive contacts serially connected in said circuit and actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level, said pair of electrically conductive contacts being selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; (b) initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position; (c) subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain the pair of contacts in said closed position; and (d) raising said drop-out level to said intermediate level by applying said flow of current solely and directly to said pair of contacts, whereby said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
Claim 12
Independent Claim
213 words
A method of interrupting the flow of current through a circuit when an overcurrent is detected, comprising the steps of: (a) providing a pair of electrically conductive contacts serially connected in said circuit and actuable to an open position by application of a magnetic field of intensity equal to or less than a predetermined drop-out level and actuable to a closed position by application of a magnetic field of intensity equal to or greater than a predetermined pull-in level, said pair of electrically conductive contacts being selected so as to have a drop-out level which increases substantially with increasing flow of current therethrough; (b) initially applying to said pair of contacts a magnetic field of intensity equal to at least said predetermined pull-in level so as to actuate said pair of contacts to said closed position; (c) subsequently reducing the intensity of said applied magnetic field to an intensity intermediate between said drop-out and said pull-in levels so as to maintain the pair of contacts in said closed position; and (d) raising said drop-out level to said intermediate level by applying said flow of current solely and directly to said pair of contacts, whereby said pair of contacts is actuated to said open position so as to interrupt the flow of current therethrough.
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) | 1981-11-20 | 1982-05-22 | 1982-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-11-20 | 1986-05-22 | 1986-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-11-20 | 1990-05-22 | 1990-11-21 | $7700.00 | Window Closed / Lapsed |