US5144846A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Minimal structure magnetostrictive stress and torque sensor
Assignee: Sensortech LP
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Filing: 1990-05-02
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Granted: 1992-09-08
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Expires: 2010-05-02
Abstract
Abstract A noncontacting method for sensing stress and torque based on the principle of magnetostriction comprises inducing a magnetic flux in a shaft (20) via such means as a single core/coil(58/60) placed close to the shaft (20) which detects torque by means of voltage or current changes in the coil (60). Another embodiment comprises two single core/coils (58/60 and 59/61) and signal processing circuitry which produces a signal minimally affected by material property inhomogeneities. An additional embodiment employs a plurality of sensors (66A/66B) strategically located around the shaft (20) to eliminate spurious signals which are due to bending stress and shaft misalignment.
Inventors
- 👤 Robert D. Klauber
- 👤 Erik B. Vigmostad
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:10
CPC Classifications
G; G01; G01L; G01L3/00; G01L3/02; G01L3/04; G01L3/10; G01L3/101; G01L3/102; G01L3/105; Y; Y10; Y10S; Y10S73/00; Y10S73/02
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
73 words
Apparatus for sensing torque in a torque transmitting member, consisting of: an electrically conductive coil for inducing a magnetic induction field flux in the torque transmitting member when said coil is energized; means for supplying constant current through said coil to energize said coil; and means for sensing the voltage across said coil which is produced by the constant current energization of said coil, to thereby determine torque in the torque transmitting member.
Claim 2
Dependent Claim
73 words
Apparatus for sensing torque in a torque transmitting member, consisting of: an electrically conductive coil for inducing a magnetic induction field flux in the torque transmitting member when said coil is energized; means for supplying constant current through said coil to energize said coil; and means for sensing the voltage across said coil which is produced by the constant current energization of said coil, to thereby determine torque in the torque transmitting member.
Claim 3
Dependent Claim
21 words
The torque sensing apparatus of claim 1 wherein said constant current supplying means supplies a constant alternating current to said coil.
Claim 4
Dependent Claim
65 words
A torque sensing method of the steps of: providing an electrically conductive coil for inducing a magnetic induction field flux in a torque transmitting member when said coil is energized; supplying constant current through said coil to energize said coil; and sensing the voltage across said coil produced by the constant current energization of said coil, to thereby determine torque in the torque transmitting member.
Claim 5
Dependent Claim
65 words
A torque sensing method of the steps of: providing an electrically conductive coil for inducing a magnetic induction field flux in a torque transmitting member when said coil is energized; supplying constant current through said coil to energize said coil; and sensing the voltage across said coil produced by the constant current energization of said coil, to thereby determine torque in the torque transmitting member.
Claim 6
Dependent Claim
20 words
The torque sensing method of claim 3 wherein said constant current supplying step a constant alternating current to said coil.
Claim 7
Dependent Claim
67 words
Apparatus for sensing stress in a member, consisting of: an electrically conductive coil for inducing a magnetic induction field flux in the member when said coil is energized; means for supplying constant current through said coil to energize said coil; and means for sensing the voltage across said coil which is produced by the constant current energization of said coil, to thereby determine stress in the member.
Claim 8
Dependent Claim
67 words
Apparatus for sensing stress in a member, consisting of: an electrically conductive coil for inducing a magnetic induction field flux in the member when said coil is energized; means for supplying constant current through said coil to energize said coil; and means for sensing the voltage across said coil which is produced by the constant current energization of said coil, to thereby determine stress in the member.
Claim 9
Dependent Claim
62 words
A stress sensing method consisting of the steps of: providing an electrically conductive coil for inducing a magnetic induction field flux in a member when said coil is energized; supplying constant current through said coil to energize said coil; and sensing the voltage across said coil produced by the constant current energization of said coil, to thereby determine stress in the member.
Claim 10
Dependent Claim
62 words
A stress sensing method consisting of the steps of: providing an electrically conductive coil for inducing a magnetic induction field flux in a member when said coil is energized; supplying constant current through said coil to energize said coil; and sensing the voltage across said coil produced by the constant current energization of said coil, to thereby determine stress in the member.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |