US3770970A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shaft angle encoder
Assignee: LUCAS LEDEX Inc
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Filing: 1972-03-15
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Granted: 1973-11-06
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Expires: 1992-03-15
Abstract
Abstract An optical shaft encoder comprising a drum adapted to rotate with the shaft and having light transmissive slots. Light from a source positioned within the drum passes radially through the slots, and is projected upon a slotted stator element positioned outside the drum. A plurality of photoelectric cells, operating as pairs in push-pull, are positioned exterior to the stator element for receiving light beams passing through slots in the stator element and for providing an electrical signal representative of shaft parameters.
Inventors
- 👤 D Trump
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:59
CPC Classifications
H; H03; H03M; H03M1/00; H03M1/12; H03M1/22; H03M1/24; H03M1/28; H03M1/30
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
175 words
An encoder responsive to rotation of a shaft, and comprising in combination; a cylindrical drum adapted to be mounted on said shaft for rotation coaxially with said shaft, said drum having a plurality of light-transmitting portions spaced substantially equiangularly about the cylindrical surface of said drum; a light source disposed within said drum to one side of the axis of rotation of said drum; a stator element having at least one array of alternately lighttransmissive and light-opaque sections, said light-transmissive sections being spaced apart by substantially the same angular increment as said portions of said drum, said element being fixedly disposed with respect to said drum such that upon rotation of said drum said light-transmissive sections are registerable radially with a like number of light-transmitting portions; means for projecting light from said source radially through a plurality of said light-transmitting portions and hence through those light-transmissive sections; as may be registered with any of said portions; and means for providing an electrical signal responsively to light transmitted through said light-transmitting portions and said light-transmissive sections.
Claim 2
Dependent Claim
175 words
An encoder responsive to rotation of a shaft, and comprising in combination; a cylindrical drum adapted to be mounted on said shaft for rotation coaxially with said shaft, said drum having a plurality of light-transmitting portions spaced substantially equiangularly about the cylindrical surface of said drum; a light source disposed within said drum to one side of the axis of rotation of said drum; a stator element having at least one array of alternately lighttransmissive and light-opaque sections, said light-transmissive sections being spaced apart by substantially the same angular increment as said portions of said drum, said element being fixedly disposed with respect to said drum such that upon rotation of said drum said light-transmissive sections are registerable radially with a like number of light-transmitting portions; means for projecting light from said source radially through a plurality of said light-transmitting portions and hence through those light-transmissive sections; as may be registered with any of said portions; and means for providing an electrical signal responsively to light transmitted through said light-transmitting portions and said light-transmissive sections.
Claim 3
Dependent Claim
37 words
An encoder as defined in claim 1 wherein said light-transmitting portions are shaped with a pair of parallel elongated straight sides, disposed with their axes of elongation parallel to one another and to said axis of rotation.
Claim 4
Dependent Claim
16 words
An encoder as defined in claim 2 wherein said portions are shaped as elongated, substantially rectangles.
Claim 5
Dependent Claim
22 words
An encoder as defined in claim 2 wherein said portions are openings through said surface, the remainder of said surface being opaque.
Claim 6
Dependent Claim
14 words
An encoder as defined iN claim 1 wherein said light-transmitting portions are lenticular elements.
Claim 7
Dependent Claim
53 words
An encoder as defined in claim 5 wherein each of said elements is shaped for focussing light projected from said source as an elongated image, each axis of elongation of each of said images being parallel to the axes of elongation of the others of said images and to said axis of rotation.
Claim 8
Dependent Claim
32 words
An encoder as defined in claim 1 wherein said light-transmitting portions are segments of cylindrical lenses all disposed with their cylindrical axes parallel to one another and to said axis of rotation.
Claim 9
Dependent Claim
22 words
An encoder as defined in claim 5 wherein at least the rim of said drum is formed substantially of a light-transparent material.
Claim 10
Dependent Claim
25 words
An encoder as defined in claim 1 wherein said stator element is at least a segment of a cylinder disposed substantially coaxially with said drum.
Claim 11
Dependent Claim
29 words
An encoder as defined in claim 9 wherein said stator element is formed of a substantially light-opaque material and said light-transmissive sections are substantially slotted openings in said material.
Claim 12
Dependent Claim
19 words
An encoder as defined in claim 1 wherein said array subtends an angle less than 90* about said drum.
Claim 13
Dependent Claim
36 words
An encoder as defined in claim 1 including a second array of alternately light-transmissive and light-opaque sections substantially similar to said first array, said two arrays subtending a total angle less than 180* about said drum.
Claim 14
Dependent Claim
63 words
An encoder as defined in claim 12 wherein said two arrays are disposed such that when the joint transmission of light through said portions of said drum and the light-transmissive sections of one of said arrays is at a maximum, the joint transmission of light through said portions and the light transmissive sections of the other of said arrays is at a minimum.
Claim 15
Dependent Claim
24 words
An encoder as defined in claim 1 wherein said means for projecting comprises a reflector positioned between said source and said axis of rotation.
Claim 16
Dependent Claim
36 words
The encoder as defined in claim 1 wherein said means for projecting comprises a substantially plane reflector positioned approximately halfway between said source and said axis of rotation substantially normally to a radius through said source.
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) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |