US3815016A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measuring thickness of nonmetallic paving material with compensation for properties of the material
Assignee: Individual
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Filing: 1971-10-08
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Granted: 1974-06-04
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Expires: 1991-10-08
Abstract
Abstract A method and apparatus for nondestructively measuring the thickness of a non-metallic layer, or wall, which utilizes a metallic sheet-like structure placed in the plane of one surface of the layer, or wall, so that apparatus to propagate an electromagnetic radiation field can be positioned against the opposite surface of the layer, or wall, and the thickness determined as a function of changes in the radiation field caused by changes in the distance between the source of the field and the metallic structure; the apparatus being calibrated remotely from the location of the metallic structure by utilizing a second metallic structure and observing the effects when positioned at known distances from the radiation field.
Inventors
- 👤 W Koob
- 👤 H Nix
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:25
CPC Classifications
G; G01; G01B; G01B15/00; G01B15/02; G01B7/00; G01B7/02; G01B7/06; G01B7/10; G01B7/105
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
147 words
Method of nondestructively measuring the thickness of a layer of essentially non-metallic building construction or paving material, comprising the steps of placing a first reflector of metallic material in contact with one surface of said layer at the location where said measuring is to be done, connecting a search coil and an indicating instrument in a circuit with the source of electrical energy to generate a high frequency electromagnetic field associated with said search coil, measuring the influence of the magnetic and electrical properties of said layer on said search coil as indicated by said indication instrument when the search coil is placed over a portion of the layer remote from said first reflector of metallic material and eliminating said influence by adjusting said circuit until the indicating instrument indicates a predetermined electrical value, then placing the search coil adjacent said measuring location and measuring said thickness.
Claim 2
Dependent Claim
147 words
Method of nondestructively measuring the thickness of a layer of essentially non-metallic building construction or paving material, comprising the steps of placing a first reflector of metallic material in contact with one surface of said layer at the location where said measuring is to be done, connecting a search coil and an indicating instrument in a circuit with the source of electrical energy to generate a high frequency electromagnetic field associated with said search coil, measuring the influence of the magnetic and electrical properties of said layer on said search coil as indicated by said indication instrument when the search coil is placed over a portion of the layer remote from said first reflector of metallic material and eliminating said influence by adjusting said circuit until the indicating instrument indicates a predetermined electrical value, then placing the search coil adjacent said measuring location and measuring said thickness.
Claim 3
Dependent Claim
110 words
The method as claimed in claim 1, including the calibration step of placing a second reflector of metallic material in the high frequency electromagnetic field of said search coil and at a predetermined distance from the search coil while in said remote location, adjusting said circuit until the indication of the instrument corresponds to an electrical value corresponding to the distance of said second reflector from the search coil, removing said second reflector and placing said search coil on said layer to be measured and at the location of said first reflector of metallic material to obtain an indication from said indicating instrument corresponding to the thickness of said layer.
Claim 4
Dependent Claim
38 words
The method of claim 2, wherein said calibration step includes the steps of positioning said second reflector at at least two different distances from said search coil to obtain two different electrical values corresponding to said two distances.
Claim 5
Dependent Claim
24 words
The method of claim 3, which includes the steps of operating said source of electrical energy at a frequency of at least 2 megahertz.
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) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |