US5247253A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Eddy current proximity sensing means and method useful for determining throttle position
Assignee: Curtis Instruments Inc
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Filing: 1990-11-09
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Granted: 1993-09-21
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Expires: 2010-11-09
Abstract
Abstract In a preferred embodiment, an inductor excited by a square-wave alternating current to produce a magnetic field in the inductor. A member movable in proximity to the inductor causes losses in the magnetic energy, which losses are directly related to the position of the member with respect to the coil. In another aspect of the invention, there is provided an inductor excited by an alternating current and a moving member which includes a ferromagnetic core having disposed thereon a thin sleeve of high resistivity material. In a further aspect of the invention, there is provided an inductor excited by an alternating current and a moving member, the excitation circuit including an oscillator having a positive temperature coefficient of frequency.
Inventors
- 👤 Scott A. Bowman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:26
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/14; G01B7/02; G01B7/023; H; H03; H03K; H03K17/00; H03K17/94; H03K17/945; H03K17/95; H03K17/952; H03K17/9525; H03K4/00; H03K4/06
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
58 words
A proximity sensor, comprising: (a) inductor means; (b) excitation means to provide an alternating bipolar square-wave current to said inductor means to produce magnetic energy therein; (c) a moving member movable in proximity to said inductor means to produce losses in said magnetic energy; and (d) means to provide an output from said sensor proportional to said losses.
Claim 2
Dependent Claim
58 words
A proximity sensor, comprising: (a) inductor means; (b) excitation means to provide an alternating bipolar square-wave current to said inductor means to produce magnetic energy therein; (c) a moving member movable in proximity to said inductor means to produce losses in said magnetic energy; and (d) means to provide an output from said sensor proportional to said losses.
Claim 3
Dependent Claim
22 words
A proximity sensor, as defined in claim 1, wherein said square-wave current to said inductor is produced by an "H" bridge driver.
Claim 4
Dependent Claim
33 words
A proximity sensor, as defined in claim 1, wherein said moving member comprises: (a) a ferromagnetic core; and (b) a relatively thin sleeve of a relatively high resistivity metal disposed upon said core.
Claim 5
Dependent Claim
26 words
A proximity sensor, as defined in claim 3, wherein said core is constructed from mild steel and said sleeve is constructed from stainless steel or brass.
Claim 6
Dependent Claim
109 words
A temperature compensated proximity sensor, comprising: (a) inductor means; (b) excitation means to provide a bipolar square-wave alternating current to said inductor means to produce magnetic energy therein, said excitation means comprising: (i) input means to receive a DC voltage; (ii) driver means to provide said alternating current to said inductor; and (iii) oscillator means, having a positive temperature coefficient with frequency, connected to said input means and connected to provide an input to said driver means; (c) a moving member movable in proximity to said inductor means to produce losses in said magnetic energy; and (d) means to provide an output from said sensor proportional to said losses.
Claim 7
Dependent Claim
109 words
A temperature compensated proximity sensor, comprising: (a) inductor means; (b) excitation means to provide a bipolar square-wave alternating current to said inductor means to produce magnetic energy therein, said excitation means comprising: (i) input means to receive a DC voltage; (ii) driver means to provide said alternating current to said inductor; and (iii) oscillator means, having a positive temperature coefficient with frequency, connected to said input means and connected to provide an input to said driver means; (c) a moving member movable in proximity to said inductor means to produce losses in said magnetic energy; and (d) means to provide an output from said sensor proportional to said losses.
Claim 8
Independent Claim
65 words
A method of measuring the proximity of a moving member to an inductor, comprising: (a) exciting said inductor with an alternating bipolar square-wave current to said inductor means to produce magnetic energy therein; and (b) measuring losses in said magnetic energy caused by the proximity of said moving member to said inductor means, the magnitude of said losses indicating the position of said moving member.
Claim 9
Independent Claim
65 words
A method of measuring the proximity of a moving member to an inductor, comprising: (a) exciting said inductor with an alternating bipolar square-wave current to said inductor means to produce magnetic energy therein; and (b) measuring losses in said magnetic energy caused by the proximity of said moving member to said inductor means, the magnitude of said losses indicating the position of said moving member.
Claim 10
Dependent Claim
21 words
A method, as defined in claim 6, further comprising providing said square-wave current to said inductor with an "H" driver bridge.
Claim 11
Dependent Claim
44 words
A method of measuring the proximity of a moving member to an inductor, as defined in claim 6, further providing said moving member comprising: (a) a ferromagnetic core; and (b) a relatively thin sleeve of a relatively high resistivity metal disposed upon said core.
Claim 12
Dependent Claim
26 words
A method, as defined in claim 8, further comprising providing said core constructed from mild steel and providing said sleeve constructed from stainless steel or brass.
Claim 13
Independent Claim
108 words
A method of measuring the proximity of a moving member to an inductor, comprising: (a) exciting said inductor with a bipolar square-wave alternating current to produce magnetic energy therein by providing: (i) input means to receive a DC voltage; (ii) driver means to provide said bipolar alternating current to said inductor; and (iii) oscillator means, having a positive temperature coefficient with frequency, connected to said input means and connected to provide an input to said driver means; and (b) measuring loses in said magnetic energy caused by the proximity of said moving member to said inductor, the magnitude of said losses indicating the position of said moving member.
Claim 14
Independent Claim
108 words
A method of measuring the proximity of a moving member to an inductor, comprising: (a) exciting said inductor with a bipolar square-wave alternating current to produce magnetic energy therein by providing: (i) input means to receive a DC voltage; (ii) driver means to provide said bipolar alternating current to said inductor; and (iii) oscillator means, having a positive temperature coefficient with frequency, connected to said input means and connected to provide an input to said driver means; and (b) measuring loses in said magnetic energy caused by the proximity of said moving member to said inductor, the magnitude of said losses indicating the position of said moving member.
Claim 15
Dependent Claim
32 words
A proximity sensor, as defined in claim 1, wherein said means to provide an output from said sensor proportional to said losses comprises means to measure the current drawn by said sensor.
Claim 16
Dependent Claim
32 words
A proximity sensor, as defined in claim 5, wherein said means to provide an output from said sensor proportional to said losses comprises means to measure the current drawn by said sensor.
Claim 17
Dependent Claim
20 words
A proximity sensor, as defined in claim 1, wherein said inductor is operatively connected to the throttle of a vehicle.
Claim 18
Dependent Claim
20 words
A proximity sensor, as defined in claim 5, wherein said inductor is operatively connected to the throttle of a vehicle.
Claim 19
Dependent Claim
24 words
A method, as defined in claim 6, wherein said step of measuring losses comprises measuring the current drawn by the components of element (a).
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) | 1996-09-20 | 1997-03-22 | 1997-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-09-20 | 2001-03-22 | 2001-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-09-20 | 2005-03-22 | 2005-09-21 | $7700.00 | Window Closed / Lapsed |