US3678737A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tubular transducer and dry couplant therefor
Assignee: Boeing North American Inc
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Filing: 1969-06-12
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Granted: 1972-07-25
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Expires: 1989-06-12
Abstract
Abstract A probe for nondestructive testing to identify internal structural defects comprises a tubular piezoelectric element adapted for low frequency vibration while moving in rolling contact over a workpiece surface. A dry adhesive couplant forms a mechanical bond between the piezoelectric element and the workpiece surface, and is also useful with disc-type probes known to the prior art, especially when the adhesive is coated with a layer of minute glass beads.
Inventors
- 👤 Darrow L Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:49
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/22; G01N29/28; B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0644; B06B1/0655; G01N29/24; G01N29/2493
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
83 words
In a probe system for nondestructively testing a workpiece to locate internal structural defects therewithin: a tubular substantially cylindrical transducer element having a length less than its diameter, and adapted to vibrate in the diametral mode in a single parabolic wave form when impressed by an electrical voltage, and support means for moving said transducer element in rolling contact with a surface of said workpiece during said vibration and along a line of movement transverse to the roll axis of said tubular tranSducer.
Claim 2
Dependent Claim
83 words
In a probe system for nondestructively testing a workpiece to locate internal structural defects therewithin: a tubular substantially cylindrical transducer element having a length less than its diameter, and adapted to vibrate in the diametral mode in a single parabolic wave form when impressed by an electrical voltage, and support means for moving said transducer element in rolling contact with a surface of said workpiece during said vibration and along a line of movement transverse to the roll axis of said tubular tranSducer.
Claim 3
Dependent Claim
43 words
The structure set forth in claim 1 abOve, further including: means for inducing a varying voltage potential between the radial innermost surface and the radial outermost surface of said tubular transducer element, said variation being at the hoop resonant frequency of said transducer.
Claim 4
Independent Claim
88 words
A method for nondestructively inspecting a workpiece to determine the presence or absence of internal structural defects therewithin, comprising: placing a tubular transducer crystal at a first location on an outer surface of said workpiece, inducing diametrical vibration in a single parabolic wave form in said tubular crystal at a predetermined frequency, moving said crystal across said workpiece surface to a second location thereon while maintaining said crystal in rolling contact with said surface, and noting any changes in said vibrations of said crystal during said movement thereof.
Claim 5
Independent Claim
88 words
A method for nondestructively inspecting a workpiece to determine the presence or absence of internal structural defects therewithin, comprising: placing a tubular transducer crystal at a first location on an outer surface of said workpiece, inducing diametrical vibration in a single parabolic wave form in said tubular crystal at a predetermined frequency, moving said crystal across said workpiece surface to a second location thereon while maintaining said crystal in rolling contact with said surface, and noting any changes in said vibrations of said crystal during said movement thereof.
Claim 6
Dependent Claim
114 words
A rotatable crystal for use in nondestructively testing a workpiece to determine the presence or absence of internal structural defects therein by acoustical vibration of said crystal during contact with said workpiece, said crystal having: a substantially cylindrical outer surface concentric with the axis of said rotation, said outer surface having a predetermined diameter, a substantially cylindrical inner surface concentric with said outer surface and defining a predetermined wall thickness therebetween, and a length sufficient to produce resonant vibration of said crystal in the diametral mode at the lowest possible frequency and in a single parabolic wave form when said crystal is impressed with a discontinuous voltage potential between said inner and outer surfaces.
Claim 7
Dependent Claim
114 words
A rotatable crystal for use in nondestructively testing a workpiece to determine the presence or absence of internal structural defects therein by acoustical vibration of said crystal during contact with said workpiece, said crystal having: a substantially cylindrical outer surface concentric with the axis of said rotation, said outer surface having a predetermined diameter, a substantially cylindrical inner surface concentric with said outer surface and defining a predetermined wall thickness therebetween, and a length sufficient to produce resonant vibration of said crystal in the diametral mode at the lowest possible frequency and in a single parabolic wave form when said crystal is impressed with a discontinuous voltage potential between said inner and outer surfaces.
Claim 8
Dependent Claim
44 words
The structure set forth in claim 4 above, further including: support means connected with said crystal and adapted to move said crystal in rolling contact with said workpiece in a direction transverse to the line of contact between said outer surface and said workpiece.
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) | 1975-07-25 | 1976-01-24 | 1976-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-25 | 1980-01-24 | 1980-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-25 | 1984-01-24 | 1984-07-25 | $7700.00 | Window Closed / Lapsed |