US3602047A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Servo pressure transducer
Assignee: Kistler Instrument Corp
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Filing: 1969-06-24
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Granted: 1971-08-31
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Expires: 1989-06-24
Abstract
Abstract Disclosed is a servo- or force-balance-type pressure transducer incorporating as the sensing element a bending beam comprising at least one bellows having a flat, flexible metal strip along one side. The beam is cantilevered at the open end of the bellows and the opposite closed end of the bellows carries a movable capacitor plate and a forcer coil. The moving assembly is balanced about the sensitive axis of the beam which coincides with its center of gravity. The forcer coil applies a restoring torque to the beam which balances out the bending forces due to pressure within the bellows, and the amount of current through the coil is an indication of this pressure.
Inventors
- 👤 Walter P Kistler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:27
CPC Classifications
G; G01; G01L; G01L13/00; G01L13/02; G01L13/023; G01L11/00; G01L11/004; G01L11/008; G01L7/00; G01L7/02; G01L7/06; G01L7/061; G01L9/00; G01L9/0033; G01L9/0038
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
102 words
A servo pressure transducer comprising a pressure-sensitive bending beam, means coupled to said bending beam for developing an electrical signal indicative of the deflection of said beam in response to a pressure fluid acting on said beam, and torquing means coupled to said beam for applying a torque to said beam in such a direction as to resist said deflection, said torquing means acting in a force balance servo loop to maintain said beam substantially straight, said bending beam being cantilevered at one end and having its other end free, said electrical-signaldeveloping means being coupled to the free end of said beam.
Claim 2
Dependent Claim
102 words
A servo pressure transducer comprising a pressure-sensitive bending beam, means coupled to said bending beam for developing an electrical signal indicative of the deflection of said beam in response to a pressure fluid acting on said beam, and torquing means coupled to said beam for applying a torque to said beam in such a direction as to resist said deflection, said torquing means acting in a force balance servo loop to maintain said beam substantially straight, said bending beam being cantilevered at one end and having its other end free, said electrical-signaldeveloping means being coupled to the free end of said beam.
Claim 3
Dependent Claim
106 words
A servo pressure transducer comPrising a pressure-sensitive bending beam, means coupled to said bending beam for developing an electrical signal indicative of the deflection of said beam in response to a pressure fluid acting on said beam, and torquing means coupled to said beam for applying a torque to said beam in such a direction as to resist said deflection, said torquing means acting in a force balance servo loop to maintain said beam substantially straight, said beam comprising a bellows open at one end and closed at the other, and a flat flexible strip secured to the successive corrugations along one side of said bellows.
Claim 4
Dependent Claim
106 words
A servo pressure transducer comPrising a pressure-sensitive bending beam, means coupled to said bending beam for developing an electrical signal indicative of the deflection of said beam in response to a pressure fluid acting on said beam, and torquing means coupled to said beam for applying a torque to said beam in such a direction as to resist said deflection, said torquing means acting in a force balance servo loop to maintain said beam substantially straight, said beam comprising a bellows open at one end and closed at the other, and a flat flexible strip secured to the successive corrugations along one side of said bellows.
Claim 5
Dependent Claim
21 words
A servo pressure transducer according to claim 2 including a second bellows symmetrically secured to the other side of said strip.
Claim 6
Dependent Claim
80 words
A servo pressure transducer comprising a pressure-sensitive bending beam cantilevered at one end and having its other end free, a variable electrical impedance adjacent said free end of said beam and variable in accordance with the deflection of said beam, a forcer coil carried by the free end of said beam and an electrical power source coupled to said impedance and to said forcer coil for feeding a signal to said forcer coil indicative of the value of said impedance.
Claim 7
Dependent Claim
80 words
A servo pressure transducer comprising a pressure-sensitive bending beam cantilevered at one end and having its other end free, a variable electrical impedance adjacent said free end of said beam and variable in accordance with the deflection of said beam, a forcer coil carried by the free end of said beam and an electrical power source coupled to said impedance and to said forcer coil for feeding a signal to said forcer coil indicative of the value of said impedance.
Claim 8
Dependent Claim
15 words
A servo pressure transducer according to claim 4 wherein said impedance comprises a capacitive pickoff.
Claim 9
Dependent Claim
147 words
A servo pressure transducer comprising a flat, flexible metal strip, a pair of bellows each having an open end and a closed end symmetrically secured to opposite sides of said strip, said bellows and strip being cantilevered at the open end of said bellows and being free at the closed end of said bellows, a cup forming a movable capacitor plate mounted on the free end of said bellows, a forcer coil carried by said cup, at least one fixed capacitor plate adjacent to but spaced from said cup, a permanent magnet adjacent said coil, a portion of said coil lying in the flux path of said permanent magnet, an electrical power source coupled to said forcer coil and said capacitor plates, and means for feeding an electrical signal from said capacitor plates to said forcer coil proportional to the change of capacitance formed by said plates.
Claim 10
Dependent Claim
147 words
A servo pressure transducer comprising a flat, flexible metal strip, a pair of bellows each having an open end and a closed end symmetrically secured to opposite sides of said strip, said bellows and strip being cantilevered at the open end of said bellows and being free at the closed end of said bellows, a cup forming a movable capacitor plate mounted on the free end of said bellows, a forcer coil carried by said cup, at least one fixed capacitor plate adjacent to but spaced from said cup, a permanent magnet adjacent said coil, a portion of said coil lying in the flux path of said permanent magnet, an electrical power source coupled to said forcer coil and said capacitor plates, and means for feeding an electrical signal from said capacitor plates to said forcer coil proportional to the change of capacitance formed by said plates.
Claim 11
Dependent Claim
34 words
A servo pressure transducer according to claim 6 wherein said bellows, cup and coil are all balanced to have a center of gravity in the plane of said strip approximately midway of its length.
Claim 12
Dependent Claim
37 words
A servo transducer according to claim 7 including a support, and a pair of crossed springs mounting said movable capacitor plate to said support, said springs being flexible about an axis passing through said center of gravity.
Claim 13
Dependent Claim
32 words
A servo pressure transducer according to claim 6 wherein said permanent magnet comprises a linear magnetized annular magnet within said coil, and an annular magnetic keeper of soft iron surrounding said coil.
Claim 14
Dependent Claim
18 words
A servo pressure transducer according to claim 6 including a plurality of permanent bar magnets within said coil.
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) | 1974-08-30 | 1975-03-01 | 1975-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-30 | 1979-03-01 | 1979-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-30 | 1983-03-01 | 1983-08-31 | $7700.00 | Window Closed / Lapsed |