Patent US1286058A successfully refreshed from Google Patents.
Patent US3777570A successfully refreshed from Google Patents.
US3777570A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid pressure transducers
Assignee: ZF International UK Ltd
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Filing: 1972-03-22
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Granted: 1973-12-11
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Expires: 1992-03-22
Abstract
Abstract A fluid pressure transducer is disclosed, said transducer includes a differential capacitor with one plate movable by a pressure sensing device. This capacitor is part of a resonant radio frequency a.c. bridge circuit, which produces an a.c. signal, and dependent on the displacement of the movable plate. A phase discriminator circuit is coupled to the bridge circuit to produce a d.c. signal the polarity and magnitude of which depend on the position of the movable plate. The output of the phase discriminator circuit is used to drive an electromagnetic force applying device which is mechanically coupled to the movable plate and to provide an output signal dependent on the position of the movable plate.
Inventors
- 👤 A Thomas
- 👤 R Heath
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:35
CPC Classifications
G; G01; G01L; G01L11/00; G01L11/004; G01L11/008; G01L9/00; G01L9/0033; G01L9/0038; G01L9/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
196 words
A fluid pressure transducer comprising: a body; a pair of spaced capacitor plates each having a planar surface, said plates being mounted on said body; a further capacitor plate; means for mounting said further capacitor plate between said pair of spaced capacitor plates for movement in a direction transverse to said planar surfaces; said pair of spaced capacitor plates and said further capacitor plate forming capacitors in two arms of a radio frequency resonant a.c. circuit; two inductors forming the other two arms of the bridge circuit, saId further capacitor plate and the inter-connection of said two inductors being coupled to the output terminals of a radio frequency oscillator, said pair of spaced capacitor plates and said inductors being connected to form the output terminals of the bridge circuit; a pressure sensitive means on said body connected to said further capacitor plate for applying a force thereto for displacing said plate in said transverse direction from a balanced position thereof; and means sensitive to said displacement of said further capacitor plate from said balanced position for applying a restoring balancing force thereto, said means further producing an electrical output signal dependent on the restoring force applied.
Claim 2
Dependent Claim
196 words
A fluid pressure transducer comprising: a body; a pair of spaced capacitor plates each having a planar surface, said plates being mounted on said body; a further capacitor plate; means for mounting said further capacitor plate between said pair of spaced capacitor plates for movement in a direction transverse to said planar surfaces; said pair of spaced capacitor plates and said further capacitor plate forming capacitors in two arms of a radio frequency resonant a.c. circuit; two inductors forming the other two arms of the bridge circuit, saId further capacitor plate and the inter-connection of said two inductors being coupled to the output terminals of a radio frequency oscillator, said pair of spaced capacitor plates and said inductors being connected to form the output terminals of the bridge circuit; a pressure sensitive means on said body connected to said further capacitor plate for applying a force thereto for displacing said plate in said transverse direction from a balanced position thereof; and means sensitive to said displacement of said further capacitor plate from said balanced position for applying a restoring balancing force thereto, said means further producing an electrical output signal dependent on the restoring force applied.
Claim 3
Dependent Claim
29 words
A transducer as claimed in claim 1 including a resistance chain connected acorss a d.c. supply and applying a known d.c. voltage level to the interconnection of said inductors.
Claim 4
Dependent Claim
31 words
A transducer as claimed in claim 1 including a radio frequency amplifier stage comprising a pair of transistors having their bases connected respectively to the output terminals of the bridge circuit.
Claim 5
Dependent Claim
29 words
A transducer as claimed in claim 3 including a capacitor interconnecting the emitters of said transistors and a transformer having its primary winding connected in parallel with said capacitor.
Claim 6
Dependent Claim
21 words
A transducer as claimed in claim 4 including a phase discrimination circuit driven by said transformer and coupled to said oscillator.
Claim 7
Dependent Claim
86 words
A transducer as claimed in claim 1, wherein said phase discrimination circuit comprises a pair of diodes connecting the ends of the secondary winding of said transformer to a pair of resistors interconnected by a pair of capacitors in series and each capacitor being in parallel with a further resistor, a center-tapping of the secondary winding of said transformer and the interconnection of said capacitors being coupled to said oscillator, and the output of said phase discrimination circuit being the voltage across said capacitors in series.
Claim 8
Dependent Claim
27 words
A transducer as claimed in claim 6 including a d.c. amplifier stage driven by said phase discrimination circuit, said d.c. amplifier driving an electromagnetic force applying device.
Claim 9
Dependent Claim
43 words
A transducer as claimed in claim 7 wherein said electromagnetic force applying device has two pairs of windings one of which is connected in a circuit with a constant current source and the other winding is in a circuit with said d.c. amplifier.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |