US4015477A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linear displacement transducer
Assignee: Fischer and Porter Co
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Filing: 1975-12-22
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Granted: 1977-04-05
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Expires: 1995-12-22
Abstract
Abstract A displacement transducer capable of accurately measuring small displacements. The transducer includes a magnetostrictive wire exposed to a stationary magnetic field and having an S-shape, one arc forming one section of the wire and the reverse arc the adjacent section. One end of the wire is fixed, whereas the other end is attached to a displaceable element whereby movement of the element changes the radius of curvature of the arcs. An amplifier whose input is connected to one section of the wire and whose output is connected to the other section thereof yields electrical pulses in the output to produce torsional vibration of the two sections, creating a sinusoidal electrical signal which is fed back to the amplifier input, thereby sustaining oscillations therein whose frequency depends on the radius of curvature and is therefore a function of the extent of displacement. Means are provided to linearize the relationship between displacement and frequency.
Inventors
- 👤 W. Jorge Sitkewich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:02
CPC Classifications
G; G01; G01L; G01L13/00; G01L13/02; G01L13/025; G01L11/00; G01L11/004; G01L11/008; G01L9/00; G01L9/16
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
185 words
A displacement transducer capable of accurately measuring a small movement of a displaceable element, said transducer comprising: A. an S-shaped wire formed of magnetostrictive material and having two arc sections, one end of the wire being fixed and the other being linked to said element, whereby movement of the element results in a change in the curvature of the arcs; B. means subjecting the wire to a stationary magnetic field; C. an amplifier whose input is connected to one section of the wire and whose output is connected to the other section thereof, whereby electrical pulses yielded in the amplifier output produce torsional vibration in the two sections to create a sinusoidal electrical signal which is fed back to the input of the amplifier, thereby sustaining oscillations in the amplifier to produce an output signal whose frequency depends on the radius of curvature of the wire sections and is therefore a function of displacement, the relationship between the output signal and displacement exhibiting non-linear deviations; and D. means associated with the wire to linearize the relationship between displacement and the frequency of the output signal.
Claim 2
Dependent Claim
185 words
A displacement transducer capable of accurately measuring a small movement of a displaceable element, said transducer comprising: A. an S-shaped wire formed of magnetostrictive material and having two arc sections, one end of the wire being fixed and the other being linked to said element, whereby movement of the element results in a change in the curvature of the arcs; B. means subjecting the wire to a stationary magnetic field; C. an amplifier whose input is connected to one section of the wire and whose output is connected to the other section thereof, whereby electrical pulses yielded in the amplifier output produce torsional vibration in the two sections to create a sinusoidal electrical signal which is fed back to the input of the amplifier, thereby sustaining oscillations in the amplifier to produce an output signal whose frequency depends on the radius of curvature of the wire sections and is therefore a function of displacement, the relationship between the output signal and displacement exhibiting non-linear deviations; and D. means associated with the wire to linearize the relationship between displacement and the frequency of the output signal.
Claim 3
Dependent Claim
20 words
A transducer as set forth in claim 1, wherein said linearization means is constituted by means mechanically preloading the wire.
Claim 4
Dependent Claim
47 words
A transducer as set forth in claim 2, wherein said arcs are 180°, and said linearization means is constituted by an adjustable fixture holding said one end of said wire to adjust the normal axial distance between said one end and the other end of the wire.
Claim 5
Dependent Claim
39 words
A transducers as set forth in claim 1, wherein said means is constituted by a reduction in the arcs of said wire to an extent less than 180°, at which the response characteristic of the transducer is substantially linear.
Claim 6
Dependent Claim
13 words
A transducer as set forth in claim 4, wherein said arcs are 170°.
Claim 7
Dependent Claim
21 words
A transducer as set forth in claim 1, wherein said displaceable element is the force beam of an open-loop differential-pressure transmitter.
Claim 8
Dependent Claim
40 words
A transducer as set forth in claim 6, wherein said beam is coupled to a pair of transducers of the type set forth in claim 1, differentially-arranged whereby a deflection of said beam expands one wire and compresses the other.
References Cited (Backward Citations)
US3371536A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-04 | 1980-10-04 | 1981-04-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-04 | 1984-10-04 | 1985-04-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-04 | 1988-10-04 | 1989-04-05 | $7700.00 | Window Closed / Lapsed |