Patent US3978299A successfully refreshed from Google Patents.
US3978299A
Expired / Lapsed
US
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Liquid-level detecting device
Assignee: Denso Corp
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Filing: 1975-05-29
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Granted: 1976-08-31
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Expires: 1995-05-29
Abstract
Abstract A liquid-level detecting device comprises a float for moving in accordance with the liquid level, a permanent magnet mounted in said float and a reed switch which is fixed to a stationary member and arranged for opening and closing in accordance with the movement of said permanent magnet and a thermoferrite member which is provided near said permanent magnet. The thermoferrite member has a Curie point at a critical temperature where it loses its magnetism thereby cutting an affection of said permanent magnet to said reed switch.
Inventors
- 👤 Norio Takai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:16
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/30; G01F23/64; G01F23/68; G01F23/70
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
83 words
A liquid-level detecting device comprising: a supporting member, a float for moving in accordance with liquid-level with respect to said supporting member, a permanent magnet mounted in said float, a reed switch fixed to said supporting member and arranged to open and close in accordance with the movement of said permanent magnet thereby to detect the liquid-level, and a thermoferrite member, provided near said permanent magnet, for cutting an effect of said permanent magnet to said reed switch in a definite temperature range.
Claim 2
Dependent Claim
83 words
A liquid-level detecting device comprising: a supporting member, a float for moving in accordance with liquid-level with respect to said supporting member, a permanent magnet mounted in said float, a reed switch fixed to said supporting member and arranged to open and close in accordance with the movement of said permanent magnet thereby to detect the liquid-level, and a thermoferrite member, provided near said permanent magnet, for cutting an effect of said permanent magnet to said reed switch in a definite temperature range.
Claim 3
Dependent Claim
69 words
A liquid-level detecting device as claimed in claim 1, wherein said permanent magnet and said thermoferrite member are placed side by side with said thermoferrite member being upperside of said permanent magnet with respect to a moving direction of said float, whereby said reed switch is closed when the temperature is below said Curie point, while said reed switch is opened when the temperature is above said Curie point.
References Cited (Backward Citations)
US3750064A
Cited
US3846747A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-31 | 1980-03-01 | 1980-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-31 | 1984-03-01 | 1984-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-31 | 1988-03-01 | 1988-08-31 | $7700.00 | Window Closed / Lapsed |