Patent US3681690A successfully refreshed from Google Patents.
US3681690A
Expired / Lapsed
US
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Optical angular accelerometer
Assignee: United States Department of the Army
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Filing: 1970-11-10
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Granted: 1972-08-01
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Expires: 1990-11-10
Abstract
Abstract An optical system for determining the angular velocity of a rotating member. The system consists of two major optical assemblies. One assembly in a catadioptric retroreflector attached to the rear end of the projectile. The other assembly is a sensor box comprising a lamp, photodetector, beam splitter, and collimating lens. The sensor box projects a collimated beam of light onto the retroreflector. Light returned by the retroreflector reenters the sensor box and is directed to the photodetector. The retroreflector contains a mirror with alternate reflecting and nonreflecting sectors. As the retroreflector rotates with the spinning member, the light returned to the sensor box is amplitude modulated. The photodetector responds to the modulation of the returning light and generates a corresponding electrical signal whose frequency is in direct proportion to the rotational rate of the spinning member.
Inventors
- 👤 Donald J Mary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:58
CPC Classifications
G; G01; G01P; G01P15/00; G01P15/16; G01P15/165; G01P3/00; G01P3/42; G01P3/44; G01P3/48; G01P3/481; G01P3/486
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
87 words
Apparatus for measuring the angular acceleration of a rotating member, comprising: a. a source of light; b. means for directing an incident beam of light from said source towards said rotating member at an oblique angle to the spin axis of said rotating member; c. a catadioptric retroreflector mounted on said rotating member for periodically reflecting said incident light beam back in a direction parallel to itself; and d. means remote from said rotating member for measuring the frequency of reception of said reflected beams of light.
Claim 2
Dependent Claim
87 words
Apparatus for measuring the angular acceleration of a rotating member, comprising: a. a source of light; b. means for directing an incident beam of light from said source towards said rotating member at an oblique angle to the spin axis of said rotating member; c. a catadioptric retroreflector mounted on said rotating member for periodically reflecting said incident light beam back in a direction parallel to itself; and d. means remote from said rotating member for measuring the frequency of reception of said reflected beams of light.
Claim 3
Dependent Claim
24 words
The apparatus of claim 1 wherein the optical axis of said catadioptric retroreflector is positioned parallel to said spin axis of said rotating member.
Claim 4
Dependent Claim
62 words
The apparatus of claim 2 wherein said catadioptric retroreflector comprises: a. an objective lens for collecting said incident beam of light; b. means located in the focal plane of said objective lens for periodically reflecting said incident beam of light; and c. means located between said objective lens and said reflecting means for miNimizing the loss of light in the reflected beams.
Claim 5
Dependent Claim
36 words
The apparatus of claim 3 wherein said means located between said objective lens and said reflecting means comprises a field lens that refracts said incident beam of light prior to its impingement upon said reflecting means.
Claim 6
Dependent Claim
30 words
The apparatus of claim 4 wherein said reflecting means comprises a reticle centered on said optical axis and having a plurality of alternating reflective and nonreflective sectors radially disposed thereon.
Claim 7
Dependent Claim
12 words
The apparatus of claim 5 wherein said light source comprises a laser.
Claim 8
Dependent Claim
55 words
The apparatus of claim 5 wherein said means for directing an incident beam of light towards said rotating member comprises: a. a lens for transforming the light from said source into a collimated beam; and b. means positioned between said light source and said lens for redirecting said reflected beams towards said frequency measuring means.
Claim 9
Dependent Claim
13 words
The apparatus of claim 7 wherein said redirecting means comprises a beam splitter.
Claim 10
Dependent Claim
13 words
The apparatus of claim 7 wherein said redirecting means comprises a half-silvered mirror.
Claim 11
Dependent Claim
26 words
The apparatus of claim 7 wherein said measuring means comprises a photosensitive device that produces an electrical pulse upon the receipt of each reflected light beam.
References Cited (Backward Citations)
DE1018660B
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |