US4221129A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Humidity sensor
Assignee: General Electric Co
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Filing: 1979-05-07
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Granted: 1980-09-09
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Expires: 1999-05-07
Abstract
Abstract A humidity sensor utilizing the electrical output of a piezoelectric crystal held in compressive stress at one end of a lever arm, the fulcrum at the other end of the lever arm consisting of a flexure hinge of moisture sensitive material with a thickness under 10 mils. The crystal is nested in a frame to which the flexure hinge is attached and the frame hinge and lever arm may be molded out of the same moisture sensitive material. A moisture sensitive form of Nylon may be used for the flexure hinge. The signal output of the crystal is a function of the compressive stress which in turn varies as the modulus of the flexure hinge varies as caused by changes in ambient humidity.
Inventors
- 👤 Donald L. Sidebottom
- 👤 Richard L. Stottmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:35
CPC Classifications
G; G01; G01N; G01N19/00; G01N19/10; G01B; G01B17/00; G01B17/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
39 words
A humidity sensor comprising a piezoelectric crystal held in compressive stress by one end of an elongated lever arm, the other end of which comprises a fulcrum section consisting of a substantially thin flexure hinge of moisture sensitive material.
Claim 2
Dependent Claim
39 words
A humidity sensor comprising a piezoelectric crystal held in compressive stress by one end of an elongated lever arm, the other end of which comprises a fulcrum section consisting of a substantially thin flexure hinge of moisture sensitive material.
Claim 3
Dependent Claim
23 words
The humidity sensor of claim 1 in which the thickness of the flexure hinge is less than 10 mils at its thinnest point.
Claim 4
Dependent Claim
19 words
The humidity sensor of claim 2 in which said hinge thickness is approximately in the range of 2-5 mils.
Claim 5
Dependent Claim
14 words
The humidity sensor of claim 1 in which the lever arm is substantially inflexible.
Claim 6
Dependent Claim
34 words
The humidity sensor of claim 1 in which the crystal is nested within a frame and the flexure hinge is attached to the frame at a point remote from the location of the crystal.
Claim 7
Dependent Claim
23 words
The humidity sensor of claim 5 in which the frame, lever arm, and flexure hinge are integrally molded of the same material throughout.
Claim 8
Dependent Claim
23 words
The humidity sensor of claim 1 or 6 in which the material used for at least the flexure hinge is moisture sensitive nylon.
Claim 9
Dependent Claim
22 words
The humidity sensor of claim 1 or 6 in which the material used for at least the flexure hinge is cellulose acetate.
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) | 1983-09-09 | 1984-03-10 | 1984-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-09 | 1988-03-10 | 1988-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-09 | 1992-03-10 | 1992-09-09 | $7700.00 | Window Closed / Lapsed |