US4687925A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Belt speed measurement using an optical fiber reflectometer
Assignee: Xerox Corp
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Filing: 1985-09-06
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Granted: 1987-08-18
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Expires: 2005-09-06
Abstract
Abstract The present invention is concerned with directly measuring belt speed by placing two high resolution single fiber optical reflectometers a known distance apart on a line parallel to the belt motion. The signal from the first reflectometer is delayed and the cross correlation function of the two signals is calculated in real time. The cross correlation function can be maximized by varying the delay. When the maximum is observed, the belt velocity may be found by dividing the reflectometer separation by the delay.
Inventors
- 👤 Raymond W. Huggins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:51
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/64; G01P3/80; G01P3/806
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
165 words
A device for measuring the speed of a moving belt, the belt including molded weft fibers, comprising a first optical reflectometer having a sense disposed adjacent to the belt for sensing a portion of the belt, a first signal provided by said first optical reflectometer, a second optical reflectometer having a sense head disposed adjacent to the belt for sensing said portion of the belt, the first optical reflectometer sense head being spaced from the second optical reflectometer a sense head a given distance on a line substantially parallel to the direction of movement of the belt, a second signal provided by said second optical reflectometer, a delay circuit for delaying said first signal, cross correlation circuitry for determining the cross correlation function of said first and second signals, the cross correlation function including a multiplicity of peaks, means to maximize the cross correlation function by varying the delay, and means to divide said given distance between the reflectometers by the amount of time delay.
Claim 2
Independent Claim
165 words
A device for measuring the speed of a moving belt, the belt including molded weft fibers, comprising a first optical reflectometer having a sense disposed adjacent to the belt for sensing a portion of the belt, a first signal provided by said first optical reflectometer, a second optical reflectometer having a sense head disposed adjacent to the belt for sensing said portion of the belt, the first optical reflectometer sense head being spaced from the second optical reflectometer a sense head a given distance on a line substantially parallel to the direction of movement of the belt, a second signal provided by said second optical reflectometer, a delay circuit for delaying said first signal, cross correlation circuitry for determining the cross correlation function of said first and second signals, the cross correlation function including a multiplicity of peaks, means to maximize the cross correlation function by varying the delay, and means to divide said given distance between the reflectometers by the amount of time delay.
Claim 3
Dependent Claim
24 words
The device of claim 1 wherein the molded weft fibers are randomly varied for reducing the multiplicity of peaks in the cross correlation function.
Claim 4
Independent Claim
139 words
A device for measuring the speed of a moving belt comprising a first optical reflectometer having a sense head disposed adjacent to the belt for sensing a portion of the belt, a first signal provided by said first optical reflectometer, a second optical reflectometer having a sense head disposed adjacent to the belt for sensing said portion of the belt, the first optical reflectometer sense head being spaced from the second optical reflectometer a sense head on a line substantially parallel to the direction of movement of the belt, a second signal provided by said second optical reflectometer, a delay circuit for delaying said first signal, cross correlation circuitry for determining the cross correlation function of said first and second signals, said cross correlation function including a multiplicity of peaks, and means for reducing the multiplicity of the peaks.
Claim 5
Independent Claim
139 words
A device for measuring the speed of a moving belt comprising a first optical reflectometer having a sense head disposed adjacent to the belt for sensing a portion of the belt, a first signal provided by said first optical reflectometer, a second optical reflectometer having a sense head disposed adjacent to the belt for sensing said portion of the belt, the first optical reflectometer sense head being spaced from the second optical reflectometer a sense head on a line substantially parallel to the direction of movement of the belt, a second signal provided by said second optical reflectometer, a delay circuit for delaying said first signal, cross correlation circuitry for determining the cross correlation function of said first and second signals, said cross correlation function including a multiplicity of peaks, and means for reducing the multiplicity of the peaks.
Claim 6
Dependent Claim
17 words
The device of claim 3, including means to maximize the cross correlation function by varying the delay.
Claim 7
Dependent Claim
21 words
The device of claim 4, including the means to divide the distance between the reflectometers by the amount of time delay.
Claim 8
Dependent Claim
81 words
In a device having first and second spaced reflectometers disposed adjacent to a belt, the belt including molded weft fibers, the spacing between individual fibers being varied randomly, the method of measuring the speed of the belt comprising the steps of the first reflectometer providing a first signal, the second reflectometer providing a second signal, delaying one of said first and second signals, determining the cross correlation function of the signals, and maximizing the cross correlation function by varying the delay.
Claim 9
Dependent Claim
81 words
In a device having first and second spaced reflectometers disposed adjacent to a belt, the belt including molded weft fibers, the spacing between individual fibers being varied randomly, the method of measuring the speed of the belt comprising the steps of the first reflectometer providing a first signal, the second reflectometer providing a second signal, delaying one of said first and second signals, determining the cross correlation function of the signals, and maximizing the cross correlation function by varying the delay.
Claim 10
Dependent Claim
22 words
The method of claim 6, including a step of to dividing the distance between the reflectometers by the amount of time delay.
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) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |