Patent US5941122A successfully refreshed from Google Patents.
US5941122A
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Liquid level sensor incorporating a capacitive rotary position encoder
Assignee: Delphi Technologies Inc
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Filing: 1997-12-04
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Granted: 1999-08-24
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Expires: 2017-12-04
Abstract
Abstract A circuit board has an arcuate array of conductor segments each subject to a digital waveform differing in phase for the various segments, and a concentric pickup conductor. A rotary encoder disk has a conductive pattern which sums and couples the waveforms from selected segments, depending on rotary position, to the pickup conductor. A synchronous phase detector generates a phase signal from the summed waveforms and the zero crossing of the phase signal is detected. A counter develops count signals used to generate the digital waveforms. The count signals are input to a latch which is clocked at the zero crossing point to latch the count value which is a digital measure of the encoder angle.
Inventors
- 👤 James Edward Nelson
- 👤 Ronald Kenneth Selby
- 👤 Raymond Lippmann
- 👤 Michael John Schnars
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:47
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/24; G01D5/241; G01D5/2412; G01D5/2415
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
202 words
A liquid level sensor having a capacitive rotary position encoder comprising: a circuit board having a plurality of conductive segments in a circular array and a pickup conductor concentric with the array; an encoder disk mounted adjacent the circuit board for rotation about an axis concentric with the array; means for supplying a pattern of digital signals to the conductive segments, the signal patterns differing in phase for each segment; an encoder conductor on the disk capacitively coupled with the pickup conductor and with some of the segments as a function of the rotary position of the encoder disk for summing selective signals and coupling the summed signals to the pickup conductor; a detector circuit connected to the pickup conductor for producing a phase signal; a circuit for determining the phase of the phase signal wherein the phase is a measure of the rotational position of the encoder disk; and a float arm having a float at one end buoyed on the liquid surface and pivoted at the other end to the encoder, the float arm being connected to the encoder disk for positioning the disk in accordance with liquid level, whereby the measured phase is a function of the liquid level.
Claim 2
Dependent Claim
202 words
A liquid level sensor having a capacitive rotary position encoder comprising: a circuit board having a plurality of conductive segments in a circular array and a pickup conductor concentric with the array; an encoder disk mounted adjacent the circuit board for rotation about an axis concentric with the array; means for supplying a pattern of digital signals to the conductive segments, the signal patterns differing in phase for each segment; an encoder conductor on the disk capacitively coupled with the pickup conductor and with some of the segments as a function of the rotary position of the encoder disk for summing selective signals and coupling the summed signals to the pickup conductor; a detector circuit connected to the pickup conductor for producing a phase signal; a circuit for determining the phase of the phase signal wherein the phase is a measure of the rotational position of the encoder disk; and a float arm having a float at one end buoyed on the liquid surface and pivoted at the other end to the encoder, the float arm being connected to the encoder disk for positioning the disk in accordance with liquid level, whereby the measured phase is a function of the liquid level.
Claim 3
Dependent Claim
59 words
The liquid level sensor as defined in claim 1 wherein: the encoder conductor includes at least one region coupled to selected segments depending on rotary position of the disk and a region capacitively coupled with the pickup conductor, so that for segments coupled to the encoder conductor the respective signals will be summed and coupled to the pickup conductor.
Claim 4
Dependent Claim
49 words
The liquid level sensor as defined in claim 1 wherein: the detector circuit comprises a synchronous detector connected to the pickup conductor for receiving the summed signals and producing a differential phase signal; and a differential amplifier is coupled to the detector circuit for amplifying the differential phase signal.
Claim 5
Dependent Claim
45 words
The liquid level sensor as defined in claim 1 wherein the means for supplying a pattern of digital signals comprises: a counter for generating a plurality of count outputs; and a logic circuit coupled to the count outputs for generating the pattern of digital signals.
Claim 6
Dependent Claim
68 words
The liquid level sensor as defined in claim 4 wherein the circuit for determining the phase of the phase signal includes: a zero crossing detector coupled to the phase signal for producing a zero crossing signal; and a latch clocked by the zero crossing signal and having data inputs comprising the count outputs, whereby the count latched by the zero crossing signal is a measure of the phase.
Claim 7
Dependent Claim
55 words
The liquid level sensor as defined in claim 5 wherein the counter comprises: a main counter providing count outputs to the logic circuit and to the latch; and a prescaler providing count outputs to the latch, whereby the count latched by the zero crossing signal is expanded to increase the resolution of the phase measurement.
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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) | 2002-08-23 | 2003-02-22 | 2003-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-23 | 2007-02-22 | 2007-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-23 | 2011-02-22 | 2011-08-24 | $7700.00 | Window Closed / Lapsed |