US4014613A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for determining changes in spacing between two positions of interest
Assignee: United States Department of the Air Force
•
Filing: 1975-09-10
•
Granted: 1977-03-29
•
Expires: 1995-09-10
Abstract
Abstract The method of determining the change in the spacing between two positions on a single object or a position on each of two objects, by affixing two linear scatterers at the two positions; illuminating the scatterers with coherent monochromatic light from a source such as a He-Ne laser and obtaining an indication of the relative movement from changes in the interference pattern. In one apparatus, linear scatterers are positioned on opposite sides of an adhesive in a lap joint. The scatterers are illuminated with light from a He-Ne laser to produce an interference pattern on a screen. Movement of a preselected fringe on the screen will provide an indication of strain in the adhesive lap joint. In another apparatus, fibers are attached to the ends of a standard bar specimen and a test bar specimen which are placed in a furnace. The fibers are then illuminated with light from a helium neon laser to produce an interference pattern. A slit in a mask is positioned at a predetermined angle with respect to the zero order fringe. A photodetector is placed behind the mask. The output of the photodetector is displayed on a strip chart recorder together with a temperature signal.
Inventors
- 👤 William N. Sharpe, Jr.
- 👤 Glenn W. Hollenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:40
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
137 words
An apparatus for obtaining data for determining the thermal coefficient of expansion of a test block of material having a predetermined length, comprising: a furnace; means for supporting said test block within said furnace; a standard block of material on said supporting means spaced a predetermined distance from said test block; said standard block having a length slightly different than said test block; a linear light scatterer fiber secured to the end of each of said blocks with the diameter of the fibers being less than the spacing between the fibers; means for passing coherent monochromtic light past said fibers to thereby produce an interference pattern; means for providing an indication of charges in said interference pattern in response to changes in temperature in said furnace; means for providing an indication of the temperature within said furnace.
Claim 2
Independent Claim
137 words
An apparatus for obtaining data for determining the thermal coefficient of expansion of a test block of material having a predetermined length, comprising: a furnace; means for supporting said test block within said furnace; a standard block of material on said supporting means spaced a predetermined distance from said test block; said standard block having a length slightly different than said test block; a linear light scatterer fiber secured to the end of each of said blocks with the diameter of the fibers being less than the spacing between the fibers; means for passing coherent monochromtic light past said fibers to thereby produce an interference pattern; means for providing an indication of charges in said interference pattern in response to changes in temperature in said furnace; means for providing an indication of the temperature within said furnace.
Claim 3
Dependent Claim
77 words
The device as recited in claim 1 wherein said means for providing an indication of changes in said interference pattern includes a mask having a slit positioned at a predetermined angle with respect to the zero order frings; a photodetector adjacent said slit; a strip chart recorder connected to said photodetector; said means for providing an indication of temperature within said furnace including a thermocouple within said furnace having its output connected to said strip chart recorder.
Claim 4
Independent Claim
121 words
The method of determining the changes of relative lengths between a test bar of material and a standard bar specimen, having a length slightly different than the length of the test bar specimen, on a support within a furnace; securing a first linear polycrystalline alumina fiber scatterer to the end, of the test bar specimen, remote from said support; securing a second linear polycrystalline alumina fiber scatterer to the end, of the standard bar specimen, remote from said support; directing a beam of coherent monochromatic light past the two linear scatterers; measuring the movement of interference fringes, past a predetermined point, resulting from the changes in spacing between the linear scatterers in response to changes in the temperature within the furnace.
Claim 5
Independent Claim
121 words
The method of determining the changes of relative lengths between a test bar of material and a standard bar specimen, having a length slightly different than the length of the test bar specimen, on a support within a furnace; securing a first linear polycrystalline alumina fiber scatterer to the end, of the test bar specimen, remote from said support; securing a second linear polycrystalline alumina fiber scatterer to the end, of the standard bar specimen, remote from said support; directing a beam of coherent monochromatic light past the two linear scatterers; measuring the movement of interference fringes, past a predetermined point, resulting from the changes in spacing between the linear scatterers in response to changes in the temperature within the furnace.
References Cited (Backward Citations)
GB1134086A
Cited
US3884581A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-28 | 1980-09-27 | 1981-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-28 | 1984-09-27 | 1985-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-28 | 1988-09-27 | 1989-03-29 | $7700.00 | Window Closed / Lapsed |