US4606231A
Expired / Lapsed
US
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Strain gauge measuring system
Assignee: Sigma Instruments Inc
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Filing: 1985-03-06
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Granted: 1986-08-19
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Expires: 2005-03-06
Abstract
Abstract In the disclosed measuring system, the strain in opposingly stressed strain gauges is measured by alternately driving currents through the gauges, and measuring the resulting differences in the alternate currents. Two reversely poled transistors, or two FETs, form low impedance switches that alternately drive the currents through the gauges. A constant current source or a resistor provides a current path to both gauges.
Inventors
- 👤 Thomas E. Beling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:13
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/16
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
57 words
A strain guage arrangement, comprising: a pair of strain gauges arranged mechanically for achieving opposite impedance effects in response to a strain; said gauges having predetermined impedances; driver means for driving current alternately through one of said gauges and then the other of said gauges; measuring means for measuring differences in the alternating currents through said gauges.
Claim 2
Dependent Claim
57 words
A strain guage arrangement, comprising: a pair of strain gauges arranged mechanically for achieving opposite impedance effects in response to a strain; said gauges having predetermined impedances; driver means for driving current alternately through one of said gauges and then the other of said gauges; measuring means for measuring differences in the alternating currents through said gauges.
Claim 3
Dependent Claim
39 words
A device as in claim 1, wherein said driver means includes a pair of switches each in series with one of said gauges and having impedances more than two orders of magnitude lower than the impedances of said gauges.
Claim 4
Dependent Claim
20 words
A device as in claim 2, wherein said switches are transistors with emitters connected to oppose currents through the gauges.
Claim 5
Dependent Claim
24 words
A device as in claim 3, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 6
Dependent Claim
28 words
A device as in claim 3, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 7
Dependent Claim
13 words
A device as in claim 2, wherein said switches are field effect transistors.
Claim 8
Dependent Claim
24 words
A device as in claim 6, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 9
Dependent Claim
28 words
A device as in claim 6, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 10
Dependent Claim
24 words
A device as in claim 2, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 11
Dependent Claim
28 words
A device as in claim 2, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 12
Dependent Claim
24 words
A device as in claim 1, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 13
Dependent Claim
28 words
A device as in claim 1, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 14
Dependent Claim
55 words
For a pair of gauges arranged mechanically to achieve opposite impedance effects in response to a strain, a circuit for measuring the strain, comprising: driver means for driving current alternately through one of said gauges and then the other of said gauges, and measuring means for measuring the differences in alternating currents through said gauges.
Claim 15
Dependent Claim
55 words
For a pair of gauges arranged mechanically to achieve opposite impedance effects in response to a strain, a circuit for measuring the strain, comprising: driver means for driving current alternately through one of said gauges and then the other of said gauges, and measuring means for measuring the differences in alternating currents through said gauges.
Claim 16
Dependent Claim
39 words
A device as in claim 13, wherein said driver means includes a pair of switches each in series with one of said gauges and having impedance more than two orders of magnitude lower than the impedance of said gauges.
Claim 17
Dependent Claim
20 words
A device as in claim 14, wherein said switches are transistors with emitters connected to oppose currents through the gauges.
Claim 18
Dependent Claim
24 words
A device as in claim 15, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 19
Dependent Claim
27 words
A device in claim 15, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 20
Dependent Claim
13 words
A device as in claim 14, wherein said switches are field effect transistors.
Claim 21
Dependent Claim
24 words
A device as in claim 18, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 22
Dependent Claim
28 words
A device as in claim 18, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 23
Dependent Claim
24 words
A device as in claim 14, wherein said driver means includes a resistor, said resistor being connected in series with each of said gauges.
Claim 24
Dependent Claim
28 words
A device as in claim 14, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
Claim 25
Dependent Claim
22 words
A device as in claim 13, wherein said driver means includes a resistor, said resistor being connected in series with said gauges.
Claim 26
Dependent Claim
28 words
A device as in claim 13, wherein said driver means includes a constant current source, said constant current source being connected in series with each of said gauges.
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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) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |