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US4429575A
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Method for inspecting a non-metallic object by means of impact elastic waves and its apparatus
Assignee: KYOEI GIKEN Co Ltd
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Filing: 1981-09-03
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Granted: 1984-02-07
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Expires: 2001-09-03
Abstract
Abstract This invention relates to a method and apparatus for inspecting a non-metallic object by means of impact elastic waves to measure the thickness of the non-metallic object such as a concrete structure, solid, etc. or to detect foreign matter contained therein. Impact elastic waves are propagated into the non-metallic object by striking an impact plate mounted thereupon with a hammer or the like.
Inventors
- 👤 Tameyuki Akishika
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 02:53
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/04; G01N29/045; G01N2291/00; G01N2291/02; G01N2291/023; G01N2291/0232; G01N2291/028; G01N2291/02854
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
184 words
Method for inspecting a non-metallic object by means of impact elastic waves comprising: propagating impact elastic waves into the non-metallic object by giving a mechanical impact to an impact plate mounted on the non-metallic object; receiving selectively a frequency exceeding several MHz out of the impact elastic waves immediately by a thickness piezoelectric element; detecting and memorizing electrically a generating time of the impact elastic waves by converting into pulse signals a specified higher frequency extracted from the selectively received frequency exceeding several MHz; receiving selectively by a deflection piezoelectric element a frequency exceeding several KHz out of the elastic waves propagated into the non-metalic object and reflected from an opposite boundary thereof or from any foreign mater contained therefrom; detecting and memorizing electrically the propagated and reflected impact elastic waves by converting into pulse signals a specified higher frequency extracted from the selectively received frequency; and the memorized generating time of the impact elastic waves being compared with a receiving time of the reflected impact waves, thereby a thickness of the non-metallic object being measured or any foreign matter contained therein being detected.
Claim 2
Dependent Claim
184 words
Method for inspecting a non-metallic object by means of impact elastic waves comprising: propagating impact elastic waves into the non-metallic object by giving a mechanical impact to an impact plate mounted on the non-metallic object; receiving selectively a frequency exceeding several MHz out of the impact elastic waves immediately by a thickness piezoelectric element; detecting and memorizing electrically a generating time of the impact elastic waves by converting into pulse signals a specified higher frequency extracted from the selectively received frequency exceeding several MHz; receiving selectively by a deflection piezoelectric element a frequency exceeding several KHz out of the elastic waves propagated into the non-metalic object and reflected from an opposite boundary thereof or from any foreign mater contained therefrom; detecting and memorizing electrically the propagated and reflected impact elastic waves by converting into pulse signals a specified higher frequency extracted from the selectively received frequency; and the memorized generating time of the impact elastic waves being compared with a receiving time of the reflected impact waves, thereby a thickness of the non-metallic object being measured or any foreign matter contained therein being detected.
Claim 3
Dependent Claim
194 words
Apparatus for inspecting a non-metallic object by means of impact elastic waves comprising: an impact plate mounted on a surface of the non-metallic object; a thickness piezoelectric element having a proper frequency exceeding several MHz, which is connected to the impact plate; a first electric circuit for converting into pulse signals the impact elastic waves responding to the thickness piezoelectric element as a result of striking the impact plate; memory and indication means for memorizing and indicating a generating time of the impact elastic waves by means of the pulse signals; a deflection piezoelectric element responding to a frequency exceeding several KHz in the impact elastic waves propagated into the non-metallic object and reflected from an opposite boundary thereof or from any foreign matter contained therein; the deflection piezoeletric element being mounted on an other surface of the non-metallic object, and a second electric circuit for converting into pulse signals the reflected waves responding to the deflection piezoelectric element; the second electric circuit being connected to the memory and indication means in which a generating time of the impact elastic waves is able to be compared with a receiving time of the reflected waves.
Claim 4
Dependent Claim
194 words
Apparatus for inspecting a non-metallic object by means of impact elastic waves comprising: an impact plate mounted on a surface of the non-metallic object; a thickness piezoelectric element having a proper frequency exceeding several MHz, which is connected to the impact plate; a first electric circuit for converting into pulse signals the impact elastic waves responding to the thickness piezoelectric element as a result of striking the impact plate; memory and indication means for memorizing and indicating a generating time of the impact elastic waves by means of the pulse signals; a deflection piezoelectric element responding to a frequency exceeding several KHz in the impact elastic waves propagated into the non-metallic object and reflected from an opposite boundary thereof or from any foreign matter contained therein; the deflection piezoeletric element being mounted on an other surface of the non-metallic object, and a second electric circuit for converting into pulse signals the reflected waves responding to the deflection piezoelectric element; the second electric circuit being connected to the memory and indication means in which a generating time of the impact elastic waves is able to be compared with a receiving time of the reflected waves.
Claim 5
Dependent Claim
39 words
Apparatus as claimed in claim 2, wherein the first electric circuit comprises a frequency tuning circuit, a single frequency tuning circuit, a wave-form correcting circuit and an output terminal, all of which are connected to each other in series.
Claim 6
Dependent Claim
42 words
Apparatus as claimed in claims 2 or 3, wherein the thickness piezoelectric element is connected to the frequency tuning circuit by way of a wire and the memory and indication means is connected to the output terminal by way of a wire.
Claim 7
Dependent Claim
32 words
Apparatus as claimed in claim 2, wherein the second electric circuit is a single frequency selecting amplifying circuit which is connected to the memory and indication means by way of a wire.
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) | 1987-02-06 | 1987-08-08 | 1988-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-06 | 1991-08-08 | 1992-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-06 | 1995-08-08 | 1996-02-07 | $7700.00 | Window Closed / Lapsed |