US3744303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pure fluidic strain gage
Assignee: United States Department of the Army
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Filing: 1971-11-23
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Granted: 1973-07-10
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Expires: 1991-11-23
Abstract
Abstract A pure fluidic strain gage is disclosed which comprises a conduit or duct constructed of deformable material through which a fluid is caused to flow. The conduit is adapted to receive an external stress and be deformed thereby in a predetermined manner such as by a change in length or the like of the conduit. This deformation produces a change in fluid resistance in the channel and thus effects a variation in the flow characteristics of the fluid through the conduit. A monitoring device, such as a fluidic proportional amplifier, is provided to detect such variations in flow characteristics, these variations being indicative of the value of the external stress received by the conduit and the strain of the conduit.
Inventors
- 👤 T Drzewiecki
- 👤 F Manion
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:35
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/02; G01B; G01B5/00; G01B5/30; Y; Y10; Y10T; Y10T137/00; Y10T137/206; Y10T137/218; Y10T137/2202; Y10T137/2207
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
122 words
A fluidic strain gage comprising a conduit means constructed of deformable material through which a fluid is caused to flow, said conduit means being adapted to receive external stress and be deformed thereby in a predetermined manner, said conduit means comprising a hollow elongated duct having at least one lateral orifice therein of a given shape and cross-sectional area communicating with the fluid flow and through which orifice at least a portion of the fluid flow exits and monitoring means for detecting variations and flow characteristics of the fluid through said orifice, said variations being effected by the conduit deformation and thus being indicative of the value of external stress received by said conduit means and the strain of said conduit means.
Claim 2
Dependent Claim
122 words
A fluidic strain gage comprising a conduit means constructed of deformable material through which a fluid is caused to flow, said conduit means being adapted to receive external stress and be deformed thereby in a predetermined manner, said conduit means comprising a hollow elongated duct having at least one lateral orifice therein of a given shape and cross-sectional area communicating with the fluid flow and through which orifice at least a portion of the fluid flow exits and monitoring means for detecting variations and flow characteristics of the fluid through said orifice, said variations being effected by the conduit deformation and thus being indicative of the value of external stress received by said conduit means and the strain of said conduit means.
Claim 3
Dependent Claim
72 words
A fluidic strain gage as defined in claim 1, wherein said conduit means comprises a hollow elongated duct of given length and internal cross-sectional area, and wherein at least a portion of the external stress is received along the longitudinal axis of the said duct whereby a variation in the length and cross-sectional area of said orifice is effected, said variation resulting in a change of the fluid resistance of said orifice.
Claim 4
Dependent Claim
147 words
A fluidic strain gage comprising a conduit means constructed of deformable material through which a fluid is caused to flow, said conduit means being adapted to receive external stress and be deformed thereby in a predetermined manner; and monitoring means detecting variations in flow characteristics of the fluid through said conduit means, said variations being effected by the conduit deformation and thus being indicative of the value of external stress received by said conduit means, wherein said conduit Means comprises a hollow tube exhibiting a plurality of bends therein of predetermined radius of curvature throughout a given longitudinal run of said tube, and wherein at least a portion of the external stress is received along the longitudinal axis of said tube, whereby a variation in the radius of curvature of said bends is effected, said variation resulting in a change of the fluid resistance of said tube.
Claim 5
Dependent Claim
147 words
A fluidic strain gage comprising a conduit means constructed of deformable material through which a fluid is caused to flow, said conduit means being adapted to receive external stress and be deformed thereby in a predetermined manner; and monitoring means detecting variations in flow characteristics of the fluid through said conduit means, said variations being effected by the conduit deformation and thus being indicative of the value of external stress received by said conduit means, wherein said conduit Means comprises a hollow tube exhibiting a plurality of bends therein of predetermined radius of curvature throughout a given longitudinal run of said tube, and wherein at least a portion of the external stress is received along the longitudinal axis of said tube, whereby a variation in the radius of curvature of said bends is effected, said variation resulting in a change of the fluid resistance of said tube.
Claim 6
Dependent Claim
51 words
A fluidic strain gage as defined in claim 1 wherein said conduit means has a plurality of lateral orifices formed therein and the external stress received by said duct effects a variation in the area of said orifices, said variation resulting in a change of the fluid resistance of said orifices.
Claim 7
Dependent Claim
49 words
A fluidic strain gage as defined in claim 4, wherein said monitoring means comprises a fluid amplifier means having control inputs communicating with said orifices, and having receiver outputs for generating a fluid output signal in dependence upon the fluid signal applied to said control inputs through said orifices.
References Cited (Backward Citations)
US2576221A
Cited
US2592569A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-09 | 1977-01-08 | 1977-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-09 | 1981-01-08 | 1981-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-09 | 1985-01-08 | 1985-07-10 | $7700.00 | Window Closed / Lapsed |