US3696290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic non-contact thickness gauge with means to compensate the effects of stray fields on the gauge
Assignee: HAYS-REPUBLIC Corp A SUBSIDIARY OF OPTIMUM CONTROL CORPORATION AN OH CORP
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Filing: 1970-07-22
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Granted: 1972-10-03
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Expires: 1990-07-22
Abstract
Abstract A thickness measuring device wherein means are positioned at opposite sides of and in selected spacing relative to a work piece being measured and respectively include magnet responsive means supported by one positioning means and a magnet supported by the other positioning means, said magnet and magnet responsive means defining a flux circuit intercepted by said work piece. The magnet responsive means include spaced parts and a third relatively small part between said spaced parts at which flux in said circuit is concentrated. A flux sensitive resistor is positioned to respond to flux variations at said third part and is connected in a Wheatstone bridge meaSuring circuit which indicates variations in the thickness of the work piece. Temperature control means including a heater and sensor means compensate for temperature variations acting on the magnetic parts, said sensor means being connected in another Wheatstone bridge measuring circuit. The sensor means may include cooperating sensors located respectively adjacent to the work piece and adjacent to the heater.
Inventors
- 👤 Hubert Dreckmann
- 👤 Charles B Wilson
- 👤 Richard K Wagenblast
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:46
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/107
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
228 words
In a device for measuring the thickness of a non-magnetic work piece and having follower means shiftable to maintain a selected spacing from one surface of said work piece, magnetically responsive means carried by said follower means, a second follower shiftable to maintain a selected spacing from the opposite surface of said work piece, magnet means carried by said second follower means for magnetically influencing said magnetically responsive means whereby magnetic flux in the responsive means is changed proportionally to variations in the space between the magnet means and the magnet responsive means occurring with changes in the thickness of said work, said magnet means having pole faces confronting said work piece, the improvement wherein said magnetically responsive means constitutes a pair of spaced magnetically susceptible parts having faces confronting said work piece and a third magnetically susceptible part smaller than said spaced parts and positioned therebetween, said spaced parts and third part cooperating with said magnet means to define a magnetic circuit in which magnetic flux is concentrated at said third part, a flux sensor carried by said third part electrical measuring means responsive to said sensor, and means for compensating for the effects of stray magnetic fields on the sensor including a stray magnetic flux sensitive means connected to said electrical measuring means to modify the output of said electrical measuring means responsive to said sensor.
Claim 2
Dependent Claim
228 words
In a device for measuring the thickness of a non-magnetic work piece and having follower means shiftable to maintain a selected spacing from one surface of said work piece, magnetically responsive means carried by said follower means, a second follower shiftable to maintain a selected spacing from the opposite surface of said work piece, magnet means carried by said second follower means for magnetically influencing said magnetically responsive means whereby magnetic flux in the responsive means is changed proportionally to variations in the space between the magnet means and the magnet responsive means occurring with changes in the thickness of said work, said magnet means having pole faces confronting said work piece, the improvement wherein said magnetically responsive means constitutes a pair of spaced magnetically susceptible parts having faces confronting said work piece and a third magnetically susceptible part smaller than said spaced parts and positioned therebetween, said spaced parts and third part cooperating with said magnet means to define a magnetic circuit in which magnetic flux is concentrated at said third part, a flux sensor carried by said third part electrical measuring means responsive to said sensor, and means for compensating for the effects of stray magnetic fields on the sensor including a stray magnetic flux sensitive means connected to said electrical measuring means to modify the output of said electrical measuring means responsive to said sensor.
Claim 3
Dependent Claim
22 words
The combination defined in claim 1, wherein said measuring means is a Wheatstone bridge measuring circuit responsive to and including said sensor.
Claim 4
Dependent Claim
173 words
A thickness measuring device comprising magnet means located at a selected distance from one face of a non-magnetic work piece, follower means positioned at a selected distance from the opposite face of said work piece, magnetically responsive means carried by said follower means and influenced by said magnet means to vary the flux intensity in said responsive means as variations in the thickness of the work piece occur, said magnetically responsive means including a pair of spaced magnetically susceptible members and a third magnetically susceptible member between and smaller than the members of said pair, said magnet means and said magnetically responsive members defining a magnetic circuit in which flux is concentrated at said third member, a resistor responsive to the flux in said third member, electrical measuring means responsive to said resistor, and means for compensation of the effects of stray magnetic fields on the resistor including a stray magnetic flux sensitive sensor connected to said electrical measuring means to modify the output of said electrical measuring means responsive to said resistor.
Claim 5
Dependent Claim
173 words
A thickness measuring device comprising magnet means located at a selected distance from one face of a non-magnetic work piece, follower means positioned at a selected distance from the opposite face of said work piece, magnetically responsive means carried by said follower means and influenced by said magnet means to vary the flux intensity in said responsive means as variations in the thickness of the work piece occur, said magnetically responsive means including a pair of spaced magnetically susceptible members and a third magnetically susceptible member between and smaller than the members of said pair, said magnet means and said magnetically responsive members defining a magnetic circuit in which flux is concentrated at said third member, a resistor responsive to the flux in said third member, electrical measuring means responsive to said resistor, and means for compensation of the effects of stray magnetic fields on the resistor including a stray magnetic flux sensitive sensor connected to said electrical measuring means to modify the output of said electrical measuring means responsive to said resistor.
Claim 6
Dependent Claim
37 words
A device as defined in claim 3, wherein said pair of magnetically susceptible members located adjacent said work have surfaces adjacent said work piece of larger area than surfaces of said magnet means located adjacent said work.
Claim 7
Dependent Claim
23 words
A device as defined in claim 1, and means for maintaining at least part of said magnetically responsive means at substantially constant temperature.
Claim 8
Dependent Claim
39 words
A device as defined in claim 1, and means for heating at least part of said magnetically responsive means, a temperature sensing means adjacent said heating means, and means responsive to said sensing means and controlling said heating means.
Claim 9
Dependent Claim
46 words
A device as defined in claim 1, and means for heating at least part of said magnetically responsive means, means sensing the temperature of said magnetically responsive means, means sensing ambient temperature, and means responsive to both of said sensing means for controlling said heating means.
Claim 10
Dependent Claim
34 words
A device as defined in claim 3, wherein said measuring means includes a Wheatstone bridge circuit, and a temperature compensating resistor, said bridge circuit including said flux responsive resistor and said temperature compensating resistor.
Claim 11
Dependent Claim
57 words
A device as defined in claim 3, wherein said measuring means includes a Wheatstone bridge circuit, a temperature compensating resistor adjacent said magnetically responsive means, and a resistor adjacent to the work piece and responsive to the temperature thereof, said flux responsive resistor, temperature compensating resistor and work temperature responsive resistor being connected in said bridge circuit.
Claim 12
Dependent Claim
62 words
A device as defined in claim 1, wherein pneumatic means control the positions of said respective follower means, said pneumatic means including nozzles located adjacent to and discharging air under pressure against opposite surfaces of the work piece and means positioning said nozzles and including resilient parts accommodating lateral deviation of the nozzles from selected positions and return thereof to selected positions.
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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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |