US3553469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement for measuring angular rotation using two moiree patterns
Assignee: Rheinmetall Air Defence AG
•
Filing: 1968-02-23
•
Granted: 1971-01-05
•
Expires: 1988-02-23
Abstract
Abstract For measuring the angular rotation between a first and second member a disc having a ringlike grating is mounted on each member. The gratings are identical, but the centers are displaced from each other. Light shining through the superimposed gratings generates Moiree patterns which are received by two groups of photocells situated diametrically opposite one another. Each group generates polyphase currents whose magnitude varies in synchronism with the motion between the gratings. The two groups of currents are evaluated to yield an angle.
Inventors
- 👤 Theo Stutz
- 👤 Peter Glauser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:24
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/36; G01D5/38
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
220 words
Arrangement for measuring angular rotation between a first member and a second member, comprising, in combination, first disc means having a first grating symmetrically placed around a first center in a first plane and mounted on said first member; second disc means having a second grating symmetrically placed around a second center in a second plane and mounted on said second member, said second plane being parallel to said first plane and a short distance therefrom, said first and second gratings each comprising a plurality of opaque lines of predetermined width alternating with transparent lines, said first and second gratings having the same grating constant and orientation, said first center being located a determined distance and direction from said second center, said first and second gratings being superimposed in a first region and a second region diametrically opposite to said first region; first and second illuminating means for illuminating said superimposed gratings, thus causing Moiree patterns to be generated upon relative motion of said first and second members; first and second readout means mounted to receive said first and second sequence of Moiree patterns, respectively, said first and second readout means being adapted, respectively, to generate electrical signals as a function of received light; and means for receiving said electrical signals and yielding an angle measurement as a function thereof.
Claim 2
Dependent Claim
220 words
Arrangement for measuring angular rotation between a first member and a second member, comprising, in combination, first disc means having a first grating symmetrically placed around a first center in a first plane and mounted on said first member; second disc means having a second grating symmetrically placed around a second center in a second plane and mounted on said second member, said second plane being parallel to said first plane and a short distance therefrom, said first and second gratings each comprising a plurality of opaque lines of predetermined width alternating with transparent lines, said first and second gratings having the same grating constant and orientation, said first center being located a determined distance and direction from said second center, said first and second gratings being superimposed in a first region and a second region diametrically opposite to said first region; first and second illuminating means for illuminating said superimposed gratings, thus causing Moiree patterns to be generated upon relative motion of said first and second members; first and second readout means mounted to receive said first and second sequence of Moiree patterns, respectively, said first and second readout means being adapted, respectively, to generate electrical signals as a function of received light; and means for receiving said electrical signals and yielding an angle measurement as a function thereof.
Claim 3
Dependent Claim
24 words
An arrangement as set forth in claim 1, wherein the width of said transparent lines is equal to the width of said opaque lines.
Claim 4
Dependent Claim
24 words
An arrangement as set forth in claim 1, wherein said first member is a stationary member and said second member is a rotating member.
Claim 5
Dependent Claim
22 words
An arrangement as set forth in claim 3, wherein said second member rotates, alternatively, in a forward and in a reverse direction.
Claim 6
Dependent Claim
27 words
An arrangement as set forth in claim 2, further comprising means for adjusting said determined distance and direction, said first center is located from said second center.
Claim 7
Dependent Claim
24 words
An arrangement as set forth in claim 5, wherein said first and second readout means, respectively, comprise a first and second group of photocells.
Claim 8
Dependent Claim
83 words
An arrangement as set forth in claim 6, wherein said first and second group of photocells each comprise at least three photocells, said first and second group of photocells thus furnishing, respectively, a first and second group of polyphase currents, the magnitude of said currents varying in synchronism with the relative motion between said first and second disc, the phase shift between current in said first group of currents being equal to the phase shift between current in said second group of currents.
Claim 9
Dependent Claim
136 words
An arrangement as set forth in claim 1, wherein said readout means comprise a first and second group of photocells, mounted in such a manner as to receive the light passing through said first and second superimposed grating regions respectively, each of said groups of photocells consisting of a plurality of photocell strips arranged substantially parallel to each other, each of said groups having a width measured in a direction substantially perpendicular to the direction of the length of said strips; and wherein the relative location of said first and second centers is such that the dark and light bands of the Moiree pattern extend in the same direction as the length of said photocell strips, and that the period of luminance change between adjacent bands corresponds to one-half the width of each of said groups.
References Cited (Backward Citations)
US2877356A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-04 | 1974-07-06 | 1975-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-04 | 1978-07-06 | 1979-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-04 | 1982-07-06 | 1983-01-05 | $7700.00 | Window Closed / Lapsed |