US3581306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Trigonometric encoder
Assignee: Individual
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Filing: 1969-08-08
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Granted: 1971-05-25
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Expires: 1989-08-08
Abstract
Abstract In a trigonometric encoder for providing a digital indication of a trigonometric function of the angle of rotation of a shaft. A rotatable disc, attached to the shaft, whose rotation is to be measured, has alternate lines of differing flux transmissive ability, which lines are parallel with each other and with the diameter of the disc. There are two sources of flux on one side on the disc and two detectors on the opposite side. Each of the detectors is aligned with its source of flux and is arranged to detect the number of times the lines interrupt the flux from the source during rotation of the disc. The number of detected interruptions along with the number of lines are utilized to provide a trigonometric indication of the angle of rotation of the disc.
Inventors
- 👤 Clark E Johnson Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:36
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/22
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
223 words
In a means for translating angular rotation into a digital value, a rotatable disc, said disc having a given number of alternate lines of constant width and of differing flux transmissive ability, with said alternate lines being parallel with each other and parallel with a diameter of said disc, a first source of flux on one side of said disc and a first detector on the opposite side of said disc in alignment with said first source, with said first detector being arranged to detect the number of times the flux from the first source is interrupted by said alternate lines during rotation of said disc, a second source of flux on one side of said disc and spaced the same distance from the center of said disc as said first source, said second source being angularly displaced a predetermined distance from said first source, and a second detector on the opposite side of the disc from said second source and aligned therewith, said second detector bEing arranged to detect the number of times the flux from the second source is interrupted by said lines during rotation of said disc, and means for using the number of interruptions detected by said first and second detectors and the number of alternate lines to provide an indication of the angle of rotation of said disc.
Claim 2
Dependent Claim
223 words
In a means for translating angular rotation into a digital value, a rotatable disc, said disc having a given number of alternate lines of constant width and of differing flux transmissive ability, with said alternate lines being parallel with each other and parallel with a diameter of said disc, a first source of flux on one side of said disc and a first detector on the opposite side of said disc in alignment with said first source, with said first detector being arranged to detect the number of times the flux from the first source is interrupted by said alternate lines during rotation of said disc, a second source of flux on one side of said disc and spaced the same distance from the center of said disc as said first source, said second source being angularly displaced a predetermined distance from said first source, and a second detector on the opposite side of the disc from said second source and aligned therewith, said second detector bEing arranged to detect the number of times the flux from the second source is interrupted by said lines during rotation of said disc, and means for using the number of interruptions detected by said first and second detectors and the number of alternate lines to provide an indication of the angle of rotation of said disc.
Claim 3
Dependent Claim
20 words
The structure of claim 1 further characterized in that said second source is angularly displaced 90* from said first source.
Claim 4
Dependent Claim
26 words
The structure of claim 1 further characterized in that said alternate lines have differing light flux transmissive ability, with each of said sources providing light flux.
Claim 5
Dependent Claim
20 words
The structure of claim 3 further characterized in that said alternate lines are provided by opaque lines on said disc.
Claim 6
Dependent Claim
76 words
The structure of claim 4 further characterized in that each of said sources includes a reflecting surface on the opposite side of said disc from its aligned detector, a light source on the same side of the disc as the detector and diammetrically positioned therefrom, and a second reflecting surface positioned on the same side of the disc as the first-named reflecting surface and positioned to reflect light from the source to the first-named reflecting surface.
Claim 7
Dependent Claim
53 words
The structure of claim 4 further characterized in that each of said detectors includes a pair of photoelectric cells, with each photoelectric cell in a pair being positioned on either side of a line drawn through the axis of rotation of said disc and generally equally between the photoelectric cells of said pair.
Claim 8
Dependent Claim
63 words
The structure of claim 4 further characterized by and including a pair of idler discs having alternate lines identical with said first-named disc and arranged for rotation in the same direction as said first-named disc at the areas of said light sources and detectors, and with the alternate lines on said idler discs being parallel to the alternate lines on said first-named disc.
Claim 9
Dependent Claim
40 words
The structure of claim 7 further characterized in that said idler discs are angularly displaced 90* apart, with the axes of rotation of said idler discs being spaced the same distance from the axis of rotation of said first-named disc.
Claim 10
Dependent Claim
63 words
The structure of claim 1 further characterized in that the cosine of the angle of rotation of said disc is determined by the formula 2N2-n12-n2 2 /2N2 where N equals the number of lines on said disc in a given distance, n1 equals the number of interruptions detected at one detector and n2 equals the number of interruptions detected at the second detector.
Claim 11
Dependent Claim
44 words
The structure of claim further characterized in that the means for using the number of interruptions detected at said first and second detectors and the number of alternate lines provides digital indication of a trigonometric function of the angle of rotation of said disc.
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) | 1974-05-24 | 1974-11-23 | 1975-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-24 | 1978-11-23 | 1979-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-24 | 1982-11-23 | 1983-05-25 | $7700.00 | Window Closed / Lapsed |