US3790276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct measurement of ship body distortion using a laser beam
Assignee: United States Department of the Navy
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Filing: 1971-04-07
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Granted: 1974-02-05
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Expires: 1991-04-07
Abstract
Abstract A laser light beam is directed to a cruciform target containing a series array of photo detectors on each arm. The light beam is perpendicular to the cruciform and is orbited about the cruciform center. A differential pulse width modulated (DPWM) wave is generated by the signals emitted from the photo detectors each time they are illuminated by the light beam, as the output of the photo detectors are connected to bi-stable flip-flops which are triggered into positive and negative states and whose pulse width depends upon the time for the rotating laser beam to travel between two arms displaced from each other by a 180* of arc. Angular distortions in the X axis and the Y axis are separately measured by two pairs of arms, the arms of each pair being displaced 180* from each other. The width of the pulse is proportional to the angular distortion.
Inventors
- 👤 G Cook
- 👤 D Milne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:16
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/08; G01M11/081; G01B; G01B11/00; G01B11/26; G01B11/27; G01B11/272; G01M5/00; G01M5/0041; G01M5/0091
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
180 words
A system for measuring distortion of a body comprising: a source of radiant energy mounted on the body for establishing a measuring reference beam of coherent light; a target for receiving and detecting said radiation fixedly mounted on the body in linear spaced relationship to said source including a plurality of photo detector banks each equally radially spaced around the reference axis of said beam and aligned therewith, thus defining a target center; a differential pulse width modulated wave generator electrically connected to said photo detector banks of said target producing pulses of equal width when said body is undistorted and therefore said source and said target are aligned on the reference axis, and producing pulses of unequal width when said body is distorted, the relative width of said pulses being indicative of the degree of distortion; and a reflective surface mounted at a 45* angle on a shaft rotatable coaxial with the reference axis of said beam and being at the target center to deflect and orbit said beam radially onto said photo detector banks surrounding the target center.
Claim 2
Independent Claim
180 words
A system for measuring distortion of a body comprising: a source of radiant energy mounted on the body for establishing a measuring reference beam of coherent light; a target for receiving and detecting said radiation fixedly mounted on the body in linear spaced relationship to said source including a plurality of photo detector banks each equally radially spaced around the reference axis of said beam and aligned therewith, thus defining a target center; a differential pulse width modulated wave generator electrically connected to said photo detector banks of said target producing pulses of equal width when said body is undistorted and therefore said source and said target are aligned on the reference axis, and producing pulses of unequal width when said body is distorted, the relative width of said pulses being indicative of the degree of distortion; and a reflective surface mounted at a 45* angle on a shaft rotatable coaxial with the reference axis of said beam and being at the target center to deflect and orbit said beam radially onto said photo detector banks surrounding the target center.
Claim 3
Dependent Claim
90 words
The system of claim 1 wherein: said banks include at least four, each positioned at the 12 o''clock, 3 o''clock, and 9 o''clock positions relative to the reference axis of said beam; each of said banks spaced 180* apart, being designated a pair; a bistable flip-flop electrically connected to each pair and changing state in response to a signal from each of said banks of said pair; whereby the output of said flip-flop is a pulse wave of equal pulse widths when said target is aligned with said reference axis.
Claim 4
Dependent Claim
51 words
The system of claim 2, wherein: the time interval for said orbiting light beam to illuminate successive semi-circular arcs of 180* are unequal when said body is distorted relative to said reference axis, said flip-flop responsive to the said signal producing a differential pulse width modulated wave indicative degree said distortion.
Claim 5
Independent Claim
140 words
A method of measuring distortion of a body comprising the steps of: projecting a beam of coherent radiant energy to illuminate and to define a reference axis to a target; arranging detectors, responsive to said radiant energy, spaced about the center of said target; driving the radiant energy in an orbital path about the center of said target when no distortion is present; distorting said projected beam from said orbital path about the center of said target in response to distortion of the body; producing a differential pulse width modulated signal proportionally responsive to the degree of distortion from said target detectors; detecting the differential pulse width modulated signals; and comparing the pulse widths of the differential pulse width modulated wave when distortion is present to the pulse width when no distortion is present, to measure the degree of distortion.
Claim 6
Independent Claim
140 words
A method of measuring distortion of a body comprising the steps of: projecting a beam of coherent radiant energy to illuminate and to define a reference axis to a target; arranging detectors, responsive to said radiant energy, spaced about the center of said target; driving the radiant energy in an orbital path about the center of said target when no distortion is present; distorting said projected beam from said orbital path about the center of said target in response to distortion of the body; producing a differential pulse width modulated signal proportionally responsive to the degree of distortion from said target detectors; detecting the differential pulse width modulated signals; and comparing the pulse widths of the differential pulse width modulated wave when distortion is present to the pulse width when no distortion is present, to measure the degree of distortion.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |