US3846729A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current limiter
Assignee: TOKYO HOSHIDEN KK
•
Filing: 1973-03-27
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Granted: 1974-11-05
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Expires: 1993-03-27
Abstract
Abstract A current limiter is provided comprising a casing housing a first and a second terminal, the first terminal being electrically connected with a thin blade-shaped bimetal. The bimetal is energized with a bias force acting lengthwise thereof so that it assumes a pair of stable positions in which its plane lies on opposite sides of a critical line. In one stable position, a contact attached to the bimetal is held in abutment against the second terminal. When the current flow through the bimetal across the first and second terminals exceeds a given value, Joule heat from the bimetal causes it to deform, inducing its snap action movement to the other stable position located on the opposite side of the critical line.
Inventors
- 👤 M Sorimachi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:08
CPC Classifications
H; H01; H01H; H01H73/00; H01H73/22; H01H73/30
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
160 words
A current limiter comprising a first and a second terminal mounted in a casing, a thin blade-shaped bimetal electrically connected with the first terminal within the casing and incapable of providing a contact pressure by itself, bias means for energizing the bimetal with a bias force acting lengthwise thereof to cause it to assume either of two stable positions in which the plane of the bimetal is respectively located on opposite sides of a critical line, said bias means serving to provide a contact pressure, a contact mounted on the surface of the bimetal and adapted to be urged against the second terminal in one of the stable positions and to move away from the second terminal in the other stable position, said bimetal when located in said other stable position being incapable of returning to said one stable position by itself, and reset means for selectively returning the bimetal from said other stable position to said one stable position.
Claim 2
Dependent Claim
160 words
A current limiter comprising a first and a second terminal mounted in a casing, a thin blade-shaped bimetal electrically connected with the first terminal within the casing and incapable of providing a contact pressure by itself, bias means for energizing the bimetal with a bias force acting lengthwise thereof to cause it to assume either of two stable positions in which the plane of the bimetal is respectively located on opposite sides of a critical line, said bias means serving to provide a contact pressure, a contact mounted on the surface of the bimetal and adapted to be urged against the second terminal in one of the stable positions and to move away from the second terminal in the other stable position, said bimetal when located in said other stable position being incapable of returning to said one stable position by itself, and reset means for selectively returning the bimetal from said other stable position to said one stable position.
Claim 3
Dependent Claim
43 words
A current limiter according to claim 1 in which one end of the blade-shaped bimetal is secured to the first terminal, said bias means supplying a bias force which acts from the other end of the blade-shaped bimetal toward the secured end thereof.
Claim 4
Dependent Claim
66 words
A current limiter according to claim 2 in which the bias means comprises a semi-elliptic spring of plate-like configuration engaging the casing at its one end and engaging the free end of the bimetal at its other end, said critical line being defined by a line extending from the point of engagement of the spring with the casing and to the secured end of the bimetal.
Claim 5
Dependent Claim
35 words
A current limiter according to claim 1 in which the bimetal is hooked onto the first terminal, the bias means being operative to exert a bias force upon the bimetal which maintains the hooked engagement.
Claim 6
Dependent Claim
66 words
A current limiter according to claim 4 in which one end of the bimetal is formed with a slot through which the first terminal extends, the bimetal being formed with an opening through which extends a column integral with the casing, said bias means comprising a semi-elliptic spring extending resiliently between the column and an edge of thE opening located nearer the contact on the bimetal.
Claim 7
Dependent Claim
75 words
A current limiter according to claim 1 wherein said reset means comprises a manually operable reset button extending through the casing wall and adapted to be advanced to and retracted from the bimetal, and second bias means for normally urging the reset button away from the bimetal, whereby the reset button can be depressed against the resilience of the second bias means to urge the bimetal toward a position of contact with the second terminal.
Claim 8
Dependent Claim
32 words
A current limiter according to claim 1, further including a third terminal mounted in the casing for abutment with the contact on the bimetal as it moves away from the second terminal.
Claim 9
Dependent Claim
23 words
A current limiter according to claim 1, further including a stop which is engaged by the bimetal moving away from the second terminal.
Claim 10
Dependent Claim
16 words
The current limiter of claim 1 wherein the bimetal has a thickness of substantially 0.15 mm.
References Cited (Backward Citations)
US2475038A
Cited
US2790046A
Cited
US3555479A
Cited
US3546650A
Cited
US3624354A
Cited
US3733571A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |