Patent US3574470A successfully refreshed from Google Patents.
US3574470A
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Method and device for detecting voids in low-density material
Assignee: National Aeronautics and Space Administration
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Filing: 1969-07-02
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Granted: 1971-04-13
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Expires: 1989-07-02
Abstract
Abstract A method and device for detecting abnormal voids in a lowdensity material such as polyurethane foam insulation wherein light is beamed into the material and the light reflected from the material is received by a photodetector which converts the light into a voltage level proportional to the light intensity received by the detector. The intensity of the reflected light decreases when the light is beamed into low-density material having an abnormal void therein and the void is indicated by resultant reduction in voltage output of the photodetector.
Inventors
- 👤 Edward K Vukelich
- 👤 William D Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:57
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
54 words
The method of claim 1 including scanning a predetermined area of said low-density material by moving said light source and said photodetector over said material while continuously transmitting a beam of light directly from said light source into said material and continuously detecting significant variations in the intensity of light reflected from said material.
Claim 2
Dependent Claim
22 words
The method of claim 2 including producing a recording indicating abnormal voids in said material and delineating the location of such voids.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein said low-density material is polyurethane foam material and said opaque backing is metal.
Claim 4
Independent Claim
228 words
A device for detecting abnormal voids in a low-density, spray-on foam material comprising: a. a housing containing a light source and a photodetector; b. said housing having a flat exterior surface adapted to contact and move over the surface of the material being inspected; c. a plurality of spaced openings in said housing extending from the interior of said housing to said exterior surface; d. said light source being mounted in alignment with one of said openings and said photodetector being mounted in alignment with another of said openings; e. said light source and said photodetector being directed outwardly of said exterior surface whereby said light source is adapted to transmit light into said material and the said photodetector is adapted to receive light reflected from said material; f. means for adjusting the spacing between said light source and said photodetector; g. means for amplifying a signal from said photodetector; h. a recorder associated with said amplifier; i. means including said amplifying means for applying a predetermined voltage to said recorder when said light source is transmitting light into sound material and applying a zero voltage to said recorder when said light source is transmitting light into a material having an abnormal void therein; and j. an arm attached to said housing for moving said housing in a scanning motion over the surface of the material being inspected.
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) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |