Patent US3825820A successfully refreshed from Google Patents.
US3825820A
Expired / Lapsed
US
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Gate circuit for non-destructive testing systems for indicating when test signals lie within predetermined limits
Assignee: Magnaflux Corp
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Filing: 1972-10-31
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Granted: 1974-07-23
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Expires: 1992-10-31
Abstract
Abstract Box gate circuit is disclosed for non-destructive testing systems such as eddy current testing systems in which first and second signals in phase quadrature relation are developed. The circuit preferably includes first and second adjustable limit circuits and first and second comparator circuits coupled to a gate circuit to develop an output signal only when the amplitude of the first signal is between limits set by the first limit circuit and the amplitude of the second signal is concurrently between limits set by the second limit circuit. Monitoring means are provided preferably including an oscilloscope and a multiplexer arrangement alternately applies the first and second signals and slow and fast sawtooth signals to the horizontal and vertical inputs of the oscilloscope with intensity of the oscilloscope spot being controlled from the output of the box gate circuit.
Inventors
- 👤 E Strauts
- 👤 J Flaherty
- 👤 E Grove
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:43
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/82; G01N27/90; G01N27/9046
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
210 words
In a non-destructive testing system, testing means operative to develop first and second signals in response to the testing of a part with the amplitude of said first signal being between a first pair of lower and upper limits and the amplitude of said second signal being concurrently between a second pair of lower and upper limits only iN response to a certain part characteristic to be detected, gate means having first and second inputs and arranged for developing an output signal only when the amplitude of a signal applied to said first input is between a first set of lower and upper limits and the amplitude of a signal applied to said second input is concurrently between a second set of lower and upper limits, said gate means including limit adjustment means for adjusting both of said first set of lower and upper limits and both of said second set of lower and upper limits to respectively correspond to said first and second pairs of lower and upper limits, means for applying said first and second signals from said testing means to said first and second inputs of said gate means, and an indicating circuit responsive to said output signal from said gate means for developing an indicating signal.
Claim 2
Dependent Claim
210 words
In a non-destructive testing system, testing means operative to develop first and second signals in response to the testing of a part with the amplitude of said first signal being between a first pair of lower and upper limits and the amplitude of said second signal being concurrently between a second pair of lower and upper limits only iN response to a certain part characteristic to be detected, gate means having first and second inputs and arranged for developing an output signal only when the amplitude of a signal applied to said first input is between a first set of lower and upper limits and the amplitude of a signal applied to said second input is concurrently between a second set of lower and upper limits, said gate means including limit adjustment means for adjusting both of said first set of lower and upper limits and both of said second set of lower and upper limits to respectively correspond to said first and second pairs of lower and upper limits, means for applying said first and second signals from said testing means to said first and second inputs of said gate means, and an indicating circuit responsive to said output signal from said gate means for developing an indicating signal.
Claim 3
Dependent Claim
44 words
In a system as defined in claim 1, monitoring means coupled to said testing means and to said limit adjustment means for indicating the amplitudes of said first and second signals in relation to said first and second sets of lower and upper limits.
Claim 4
Dependent Claim
41 words
In a system as defined in claim 2, said monitoring means including oscilloscope means including a screen and having horizontal and vertical inputs, and means for applying said first and second signals to said horizontal and vertical inputs of said oscilloscope.
Claim 5
Dependent Claim
92 words
In a system as defined in claim 3, said monitoring means further including circuit means coupled to said oscilloscope means for producing on said screen an indication of the boundaries of a rectangular area corresponding to said first and second sets of lower and upper limits, the positions of one pair of opposite boundaries of said area corresponding to said lower and upper limits of said first set and the positions of the other pair of opposite boundaries of said area corresponding to said lower and upper limits of said second set.
Claim 6
Dependent Claim
47 words
In a system as defined in claim 4, wherein said oscilloscope includes an intensity control input, said circuit means including intensity control means coupled to said intensity control input for controlling the brightness of said area in relation to the brightness of remaining areas of said screen.
Claim 7
Dependent Claim
55 words
In a system as defined in claim 5, said circuit means including slow and fast sawtooth circuit means for developing sawtooth signals at slow and fast rates, and multiplexer means for alternately applying said first and second signals and said slow and fast sawtooth signals to said horizontal and vertical inputs of said oscilloscope means.
Claim 8
Dependent Claim
41 words
In a system as defined in claim 6, said intensity control means being responsive to said output signal from said gate means during application of said slow and fast sawtooth signals to said horizontal and vertical inputs of said oscilloscope means.
Claim 9
Dependent Claim
33 words
In a system as defined in claim 6, means for disabling said indicating circuit during application of said slow and fast sawtooth signals to said horizontal and vertical inputs of said oscilloscope means.
Claim 10
Dependent Claim
46 words
In a system as defined in claim 6, means providing a synchronizing connection between said slow and fast sawtooth circuit means to operate said slow sawtooth circuit means at a rate equal to a sub-multiple of the rate of operation of said fast sawtooth circuit means.
Claim 11
Dependent Claim
30 words
In a system as defined in claim 6, flip-flop means for controlling said multiplexer means, and means for applying triggering signals from said slow sawtooth means to said flip-flop means.
Claim 12
Dependent Claim
40 words
In a system as defined in claim 6, switch means for selectively placing said multiplexer means in a condition in which only said first and second test signals are applied to said horizontal and vertical inputs of said oscilloscope means.
Claim 13
Dependent Claim
186 words
In a system as defined in claim 1, said limit adjustment means comprising a first limit adjustment circuit having a pair of output terminals at different potentials, and a second limit adjustment circuit having a pair of output terminals at different potentials, and said Gate means further comprising a first signal comparator responsive to a signal applied to said first input and coupled to said output terminals of said first limit adjustment circuit for developing a first control signal only when the amplitude of said first signal is between the potentials of said output terminals of said first limit circuit, a second signal comparator responsive to a signal applied to said second input and coupled to said output terminals of said second limit adjustment circuit for developing a second control signal only when the amplitude of said second signal is between the potentials of said output terminals of said second limit adjustment circuit, and gate circuits responsive to said first and second control signals and arranged to develop said output signal only in response to concurrence of said first and second control signals from said comparators.
Claim 14
Dependent Claim
43 words
In a system as defined in claim 12, each of said limit adjustment circuits comprising a pair of ganged adjustable resistors coupled between said output terminals and positive and negative voltage supply terminals, and a third adjustable resistor connected between said output terminals.
Claim 15
Dependent Claim
57 words
In a system as defined in claim 1, said testing means comprising AC supply means, part inspection means coupled to said AC supply means and arranged for developing a test signal having a wave shape corresponding to characteristics of the part, and signal developing means responsive to said test signal for developing said first and second signals.
Claim 16
Dependent Claim
49 words
In a system as defined in claim 14, said signal developing means comprising first and second phase detector means coupled to said AC supply means and responsive to said test signal for developing said first and second signals proportion to components of said test signal in phase quadrature relation.
Claim 17
Dependent Claim
25 words
In a system as defined in claim 15, adjustable phase rotation means coupled between said AC supply means and said first and second phase detectors.
Claim 18
Dependent Claim
36 words
In a system as defined in claim 14, said part inspection means comprising an inspection coil unit including a primary coil coupled to said AC supply means and secondary coil means for developing said test signal.
Claim 19
Dependent Claim
32 words
In a system as defined in claim 17, said secondary coil means including a pair of differentially connected secondary coils in spaced relation for inductive association with spaced portions of the part.
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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |